Search

As the most abundant small RNAs, piwi-interacting RNAs (piRNAs) have been identified as a new class of non-coding RNAs with 24-32 nucleotides in length, and they are expressed at high levels in male germ cells. PiRNAs have been implicated in the regulation of several biological processes, including cell differentiation, development, and male reproduction. In this review, we focused on the functions and molecular mechanisms of piRNAs in controlling spermatogenesis, including genome stability, regulation of gene expression, and male germ cell development. The piRNA pathways include two major pathways, namely the pre-pachytene piRNA pathway and the pachytene piRNA pathway. In the pre-pachytene stage, piRNAs are involved in chromosome remodeling and gene expression regulation to maintain genome stability by inhibiting transposon activity. In the pachytene stage, piRNAs mediate the development of male germ cells via regulating gene expression by binding to mRNA and RNA cleavage. We further discussed the correlations between the abnormalities of piRNAs and male infertility and the prospective of piRNAs' applications in reproductive medicine and future studies. This review provides novel insights into mechanisms underlying mammalian spermatogenesis and offers new targets for diagnosing and treating male infertility., (© 2024. The Author(s).)

Plant-derived extracellular vesicles (EVs), containing a myriad of bioactive proteins, microRNAs, lipids, and secondary metabolites, have recently become the focus of rising interest due to their important roles in various applications. The widely accepted method for isolating plant EVs is differential ultracentrifugation plus density gradient centrifugation. However, the combination of differential ultracentrifugation and density gradient centrifugation for the isolation of plant EVs is time-consuming and labor-intensive. Hence, there is a need for more efficient methods to perform the separation of plant EVs. In this study, EVs were separated from Arabidopsis thaliana leaves by a cost-effective polyethylene glycol (PEG)-based precipitation approach. The mean size of purified Arabidopsis thaliana EVs determined by dynamic light scattering was 266 nm, which is consistent with nanoparticle tracking analysis. The size was also confirmed via transmission electron microscopy with morphology of a cup-shaped appearance which is the typical mammalian exosome's morphology. Additionally, Western blotting of the purified Arabidopsis thaliana EVs, using commercially available mammalian exosomal kits, displayed surface marker tetraspanin proteins (CD9, CD63, and CD81), and endosomal sorting complexes required for transport (ESCRT)-associated proteins (TSG101 and ALIX). This demonstrates that the purified Arabidopsis thaliana EVs reveal the typical proteins reported in mammalian exosomes., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Short-, medium-, and long-chain chlorinated paraffins (CPs) (SCCPs, MCCPs, and LCCPs) and dechloranes are chemicals of emerging concern; however, little is known of their bioaccumulative potential compared to legacy contaminants in marine mammals. Here, we analyzed SCCPs, MCCPs, LCCPs, 7 dechloranes, 4 emerging brominated flame retardants, and 64 legacy contaminants, including polychlorinated biphenyls (PCBs), in the blubber of 46 individual marine mammals, representing 10 species, from Norway. Dietary niche was modeled based on stable isotopes of nitrogen and carbon in the skin/muscle to assess the contaminant accumulation in relation to diet. SCCPs and dechlorane-602 were strongly positively correlated with legacy contaminants and highest in killer ( Orcinus orca ) and sperm ( Physeter macrocephalus ) whales (median SCCPs: 160 ng/g lw; 230 ng/g lw and median dechlorane-602: 3.8 ng/g lw; 2.0 ng/g lw, respectively). In contrast, MCCPs and LCCPs were only weakly correlated to recalcitrant legacy contaminants and were highest in common minke whales ( Balaenoptera acutorostrata ; median MCCPs: 480 ng/g lw and LCCPs: 240 ng/g lw). The total contaminant load in all species was dominated by PCBs and legacy chlorinated pesticides (63-98%), and MCCPs dominated the total CP load (42-68%, except 11% in the long-finned pilot whale Globicephala melas ). Surprisingly, we found no relation between contaminant concentrations and dietary niche, suggesting that other large species differences may be masking effects of diet such as lifespan or biotransformation and elimination capacities. CP and dechlorane concentrations were higher than in other marine mammals from the (sub)Arctic, and they were present in a killer whale neonate, indicating bioaccumulative properties and a potential for maternal transfer in these predominantly unregulated chemicals.

Clathrin-coated vesicles (CCVs), generated by clathrin-mediated endocytosis (CME), are essential eukaryotic trafficking organelles that transport extracellular and plasma membrane-bound materials into the cell. In this Review, we explore mechanisms of CME in mammals, yeasts and plants, and highlight recent advances in the characterization of endocytosis in plants. Plants separated from mammals and yeast over 1.5 billion years ago, and plant cells have distinct biophysical parameters that can influence CME, such as extreme turgor pressure. Plants can therefore provide a wider perspective on fundamental processes in eukaryotic cells. We compare key mechanisms that drive CCV formation and explore what these mechanisms might reveal about the core principles of endocytosis across the tree of life. Fascinatingly, CME in plants appears to more closely resemble that in mammalian cells than that in yeasts, despite plants being evolutionarily further from mammals than yeast. Endocytic initiation appears to be highly conserved across these three systems, requiring similar protein domains and regulatory processes. Clathrin coat proteins and their honeycomb lattice structures are also highly conserved. However, major differences are found in membrane-bending mechanisms. Unlike in mammals or yeast, plant endocytosis occurs independently of actin, highlighting that mechanistic assumptions about CME across different systems should be made with caution., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

In mammals, seasonal opportunities and challenges are anticipated through programmed changes in physiology and behavior. Appropriate anticipatory timing depends on synchronization to the external solar year, achieved through the use of day length (photoperiod) as a synchronizing signal. In mammals, nocturnal production of melatonin by the pineal gland is the key hormonal mediator of photoperiodic change, exerting its effects via the hypothalamopituitary axis. In this review/perspective, we consider the key developments during the history of research into the seasonal synchronizer effect of melatonin, highlighting the role that the pars tuberalis-tanycyte module plays in this process. We go on to consider downstream pathways, which include discrete hypothalamic neuronal populations. Neurons that express the neuropeptides kisspeptin and (Arg)(Phe)-related peptide-3 (RFRP-3) govern seasonal reproductive function while neurons that express somatostatin may be involved in seasonal metabolic adaptations. Finally, we identify several outstanding questions, which need to be addressed to provide a much thorough understanding of the deep impact of melatonin upon seasonal synchronization., (© 2024 The Author(s). Journal of Pineal Research published by John Wiley & Sons Ltd.)

In this last article of the trilogy, the unified biothermokinetic theory of ATP synthesis developed in the previous two papers is applied to a major problem in comparative physiology, biochemistry, and ecology-that of metabolic scaling as a function of body mass across species. A clear distinction is made between intraspecific and interspecific relationships in energy metabolism, clearing up confusion that had existed from the very beginning since Kleiber first proposed his mouse-to-elephant rule almost a century ago. It is shown that the overall mass exponent of basal/standard metabolic rate in the allometric relationship [Formula: see text] is composed of two parts, one emerging from the relative intraspecific constancy of the slope (b), and the other (b ' ) arising from the interspecific variation of the mass coefficient, a(M) with body size. Quantitative analysis is shown to reveal the hidden underlying relationship followed by the interspecific mass coefficient, a(M)=P 0 M 0.10 , and a universal value of P 0 =3.23 watts, W is derived from empirical data on mammals from mouse to cattle. The above relationship is shown to be understood only within an evolutionary biological context, and provides a physiological explanation for Cope's rule. The analysis also helps in fundamentally understanding how variability and a diversity of scaling exponents arises in allometric relations in biology and ecology. Next, a molecular-level understanding of the scaling of metabolism across mammalian species is shown to be obtained by consideration of the thermodynamic efficiency of ATP synthesis η, taking mitochondrial proton leak as a major determinant of basal metabolic rate in biosystems. An iterative solution is obtained by solving the mathematical equations of the biothermokinetic ATP theory, and the key thermodynamic parameters, e.g. the degree of coupling q, the operative P/O ratio, and the metabolic efficiency of ATP synthesis η are quantitatively evaluated for mammals from rat to cattle. Increases in η (by ∼15%) over a 2000-fold body size range from rat to cattle, primarily arising from an ∼3-fold decrease in the mitochondrial H + leak rate are quantified by the unified ATP theory. Biochemical and mechanistic consequences for the interpretation of basal metabolism, and the various molecular implications arising are discussed in detail. The results are extended to maximum metabolic rate, and interpreted mathematically as a limiting case of the general ATP theory. The limitations of the analysis are pointed out. In sum, a comprehensive quantitative analysis based on the unified biothermokinetic theory of ATP synthesis is shown to solve a central problem in biology, physiology, and ecology on the scaling of energy metabolism with body size., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

There is global demand for novel ecotoxicity testing tools that are based on alternative to animal models, have high throughput potential, and may be applicable to a wide diversity of taxa. Here we scaled up a microplate-based cell-free neurochemical testing platform to screen 800 putative endocrine disrupting chemicals from the U.S. Environmental Protection Agency's ToxCast e1k library against the glutamate (NMDA), muscarinic acetylcholine (mACh), and dopamine (D2) receptors. Each assay was tested in cellular membranes isolated from brain tissues from a representative bird (zebra finch = Taeniopygia castanotis), mammal (mink = Neogale vison), and fish (rainbow trout = Oncorhynchus mykiss). The primary objective of this short communication was to make the results database accessible, while also summarising key attributes of assay performance and presenting some initial observations. In total, 7200 species-chemical-assay combinations were tested, of which 453 combinations were classified as a hit (radioligand binding changed by at least 3 standard deviations). There were some differences across species, and most hits were found for the D2 and NMDA receptors. The most active chemical was C.I. Solvent Yellow 14 followed by Diphenhydramine hydrochloride, Gentian Violet, SR271425, and Zamifenacin. Nine chemicals were tested across multiple plates with a mean relative standard deviation of the specific radioligand binding data being 24.6%. The results demonstrate that cell-free assays may serve as screening tools for large chemical libraries especially for ecological species not easily studied using traditional methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Human brain aging is characterized by the production and deposition of β-amyloid (Aβ) in the form of senile plaques and cerebral amyloid angiopathy and the intracellular accumulation of hyper-phosphorylated tau (Hp-tau) to form neurofibrillary tangles (NFTs) and dystrophic neurites of senile plaques. The process progresses for years and eventually manifests as cognitive impairment and dementia in a subgroup of aged individuals. Aβ is produced and deposited first in the neocortex in most aged mammals, including humans; it is usually not accompanied by altered behavior and cognitive impairment. Hp-tau is less frequent than Aβ pathology, and NFTs are rare in most mammals. In contrast, NFTs are familiar from middle age onward in humans; NFTs first appear in the paleocortex and selected brain stem nuclei. NFTs precede for decades or years Aβ deposition and correlate with dementia in about 5% of individuals at the age of 65 and 25% at the age of 85. Based on these comparative data, (a) Aβ deposition is the most common Alzheimer's disease neuropathological change (ADNC) in the brain of aged mammals; (b) Hp-tau is less common, and NFTs are rare in most aged mammals; however, NFTs are the principal cytoskeletal pathology in aged humans; (c) NFT in aged humans starts in selected nuclei of the brain stem and paleocortical brain regions progressing to the most parts of the neocortex and other regions of the telencephalon; (d) human brain aging is unique among mammalian species due to the early appearance and dramatic progression of NFTs from middle age onward, matching with cognitive impairment and dementia in advanced cases; (e) neither mammalian nor human brain aging supports the concept of the amyloid cascade hypothesis.

Proton-coupled oligopeptide transporters (POTs) are of great pharmaceutical interest owing to their promiscuous substrate binding site that has been linked to improved oral bioavailability of several classes of drugs. Members of the POT family are conserved across all phylogenetic kingdoms and function by coupling peptide uptake to the proton electrochemical gradient. Cryo-EM structures and alphafold models have recently provided new insights into different conformational states of two mammalian POTs, SLC15A1, and SLC15A2. Nevertheless, these studies leave open important questions regarding the mechanism of proton and substrate coupling, while simultaneously providing a unique opportunity to investigate these processes using molecular dynamics (MD) simulations. Here, we employ extensive unbiased and enhanced-sampling MD to map out the full SLC15A2 conformational cycle and its thermodynamic driving forces. By computing conformational free energy landscapes in different protonation states and in the absence or presence of peptide substrate, we identify a likely sequence of intermediate protonation steps that drive inward-directed alternating access. These simulations identify key differences in the extracellular gate between mammalian and bacterial POTs, which we validate experimentally in cell-based transport assays. Our results from constant-PH MD and absolute binding free energy (ABFE) calculations also establish a mechanistic link between proton binding and peptide recognition, revealing key details underpining secondary active transport in POTs. This study provides a vital step forward in understanding proton-coupled peptide and drug transport in mammals and pave the way to integrate knowledge of solute carrier structural biology with enhanced drug design to target tissue and organ bioavailability., Competing Interests: SL, JP, SN, PB No competing interests declared, (© 2024, Lichtinger et al.)

Autophagy is a self-catabolic process through which cellular components are delivered to lysosomes for degradation. There are three types of autophagy, i.e., macroautophagy, chaperone-mediated autophagy (CMA), and microautophagy. In macroautophagy, a portion of the cytoplasm is wrapped by the autophagosome, which then fuses with lysosomes and delivers the engulfed cytoplasm for degradation. In CMA, the translocation of cytosolic substrates to the lysosomal lumen is directly across the limiting membrane of lysosomes. In microautophagy, lytic organelles, including endosomes or lysosomes, take up a portion of the cytoplasm directly. Although macroautophagy has been investigated extensively, microautophagy has received much less attention. Nonetheless, it has become evident that microautophagy plays a variety of cellular roles from yeast to mammals. Here we review the very recent updates of microautophagy. In particular, we focus on the feature of the degradative substrates and the molecular machinery that mediates microautophagy., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Oxytocin (OXT), a neuropeptide consisting of only nine amino acids, is synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Although OXT is best known for its role in lactation and parturition, recent research has shown that it also has a significant impact on social behaviors in mammals. However, a comprehensive review of this topic is still lacking. In this paper, we systematically reviewed the effects of OXT on social behavior in mammals. These effects of OXT from the perspective of five key behavioral dimensions were summarized: parental behavior, anxiety, aggression, attachment, and empathy. To date, researchers have agreed that OXT plays a positive regulatory role in a wide range of social behaviors, but there have been controversially reported results. In this review, we have provided a detailed panorama of the role of OXT in social behavior and, for the first time, delved into the underlying regulatory mechanisms, which may help better understand the multifaceted role of OXT. Levels of OXT in previous human studies were also summarized to provide insights for diagnosis of mental disorders., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The white shrimp Penaeus (Litopenaeus) vannamei is the most cultivated shrimp worldwide. Compared to other shrimp species, it has higher resistance to adverse conditions. During hypoxia, the shrimp reduces oxygen consumption and adjusts energy metabolism via anaerobic glycolysis, among other strategies. Hexokinase (HK) is the first enzyme of glycolysis and a key regulation point. In mammals and other vertebrates, there are several tissue-specific HK isoforms with differences in expression and enzyme activity. In contrast, crustacean HKs have been relatively little studied. We studied the P. vannamei HK isoforms during hypoxia and reoxygenation. We cloned two HK1 sequences named HK1-long (1455 bp) and HK1-short (1302 bp), and one HK2 (1344 bp). In normoxia, total HK1 expression is higher in hepatopancreas, while HK2 is higher in gills. Severe hypoxia (1 mg/L of DO) after 12 h exposure and 1 h of reoxygenation increased HK1 expression in both organs, but HK2 expression changed differentially. In hepatopancreas, HK2 expression increased in 6 and 12 h of hypoxia but diminished to normoxia levels after reoxygenation. In gills, HK2 expression decreased after 12 h of hypoxia. HK activity increased in hepatopancreas after 12 h hypoxia, opposite to gills. These results indicate that shrimp HK isoforms respond to hypoxia and reoxygenation in a tissue-specific manner. Intracellular glucose levels did not change in any case, showing the shrimp ability to maintain glucose homeostasis during hypoxia., Competing Interests: Declaration of competing interest The authors declare no competing or financial interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Respiratory syncytial virus (RSV) is a highly contagious virus that affects the lungs and respiratory passages of many vulnerable people. It is a leading cause of lower respiratory tract infections and clinical complications, particularly among infants and elderly. It can develop into serious complications such as pneumonia and bronchiolitis. The development of RSV vaccine or immunoprophylaxis remains highly active and a global health priority. Currently, GSK's Arexvy™ vaccine is approved for the prevention of lower respiratory tract disease in older adults (>60 years). Palivizumab and currently nirsevimab are the approved monoclonal antibodies (mAbs) for RSV prevention in high-risk patients. Many studies are ongoing to develop additional therapeutic antibodies for preventing RSV infections among newborns and other susceptible groups. Recently, additional antibodies have been discovered and shown greater potential for development as therapeutic alternatives to palivizumab and nirsevimab. Plant expression platforms have proven successful in producing recombinant proteins, including antibodies, offering a potential cost-effective alternative to mammalian expression platforms. Hence in this study, an attempt was made to use a plant expression platform to produce two anti-RSV fusion (F) mAbs 5C4 and CR9501. The heavy-chain and light-chain sequences of both these antibodies were transiently expressed in Nicotiana benthamiana plants using a geminiviral vector and then purified using single-step protein A affinity column chromatography. Both these plant-produced mAbs showed specific binding to the RSV fusion protein and demonstrate effective viral neutralization activity in vitro . These preliminary findings suggest that plant-produced anti-RSV mAbs are able to neutralize RSV in vitro .

Transient gene expression (TGE) in mammalian cells is a well-known approach to the fast expression of recombinant proteins. The human cell line HEK (human embryonic kidney) 293F is widely used in this field, due to its adaptability to grow in suspension to high cell densities in serum-free media, amenability to transfection, and production of recombinant proteins in satisfactory quantities for functional and structural analysis. Amounts of plasmid DNA (pDNA) required in transfections for TGE remain high (usually 1 µg pDNA/mL, or even higher), representing a noticeable proportion of the overall cost. Thus, there is an economic need to reduce amounts of coding pDNA in TGE processes. In this work, amounts of both pDNA and transfecting agent used for TGE in HEK 293F cells have been explored in order to reduce them without compromising (or even improving) the productivity of the process in terms of protein yield. In our hands, minimal polyethyleneimine (PEI) cytotoxicity and optimum protein yields were obtained when transfecting at 0.5 µg pDNA/mL (equal to 0.5 µg pDNA/million cells) and a DNA-to-PEI ratio of 1:3, a trend confirmed for several unrelated recombinant proteins. Thus, carefully tuning pDNA and transfecting agent amounts not only reduces the economic costs but also results in higher recombinant protein yields. These results surely have a direct application and interest for the biopharmaceutical industry, always concerned in increasing productivity while decreasing economic costs. KEY POINTS: • Mammalian cells are widely used to produce recombinant proteins in short times. • Tuning DNA and transfecting agent are of great interest to optimize economic costs. • Reducing DNA and transfecting agent amounts result in higher protein yields., (© 2024. The Author(s).)

The view on nuclear filaments formed by non-skeletal β-actin has significantly changed over the decades. Initially, filamentous actin was observed in amphibian oocyte nuclei and only under specific cell stress conditions in mammalian cell nuclei. Improved labeling and imaging technologies have permitted insights into a transient but microscopically apparent filament network that is relevant for chromatin organization, biomechanics of the mammalian cell nucleus, gene expression, and DNA damage repair. Here, we will provide a historical perspective on the developing insight into nuclear actin filaments.

In Brief: Chromosome missegregation and declining energy metabolism are considered to be unrelated features of oocyte ageing that contribute to poor reproductive outcomes. Given the bioenergetic cost of chromosome segregation, we propose here that altered energy metabolism during ageing may be an underlying cause of age-related chromosome missegregation and aneuploidy., Abstract: Advanced reproductive age in women is a major cause of infertility, miscarriage and congenital abnormalities. This is principally caused by a decrease in oocyte quality and developmental competence with age. Oocyte ageing is characterised by an increase in chromosome missegregation and aneuploidy. However, the underlying mechanisms of age-related aneuploidy have not been fully elucidated and are still under active investigation. In addition to chromosome missegregation, oocyte ageing is also accompanied by metabolic dysfunction. In this review, we integrate old and new perspectives on oocyte ageing, chromosome segregation and metabolism in mammalian oocytes and make direct links between these processes. We consider age-related alterations to chromosome segregation machinery, including the loss of cohesion, microtubule stability and the integrity of the spindle assembly checkpoint. We focus on how metabolic dysfunction in the ageing oocyte disrupts chromosome segregation machinery to contribute to and exacerbate age-related aneuploidy. More specifically, we discuss how mitochondrial function, ATP production and the generation of free radicals are altered during ageing. We also explore recent developments in oocyte metabolic ageing, including altered redox reactions (NAD+ metabolism) and the interactions between oocytes and their somatic nurse cells. Throughout the review, we integrate the mechanisms by which changes in oocyte metabolism influence age-related chromosome missegregation.

Ethnopharmacological Relevance: The Moutan cortex (MC), the root bark of Paeonia suffruticosa Anderws (Paeoniaceae), has been historically employed in traditional herbal medicine for addressing women's ailments by replenishing kidney Yin., Aim of the Study: We aimed to explore if paeonol, an active constituent of MC, could ameliorate neuropsychiatric symptoms, such as anxiety, depression, and cognitive impairments, associated with post-menopausal syndrome (PMS) in an ovariectomized (OVX) mouse model., Materials and Methods: The experimental design comprised 6 groups, including a sham group, OVX group, paeonol administration groups (3, 10 or 30 mg/kg, p.o.), and an estradiol (E2)-treated positive control group. Behavioral tests including the open field, novel object recognition, Y-maze, elevated plus-maze, splash, and forced swimming tests were conducted. In addition, we investigated the effets of paeonol on the phosphorylated levels of phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR), as well as on the expression levels of G protein-coupled receptor (GPR30) and brain-derived neurotrophic factor (BDNF) in the prefrontal cortex and hippocampus., Results: Paeonol treatment (10 and 30 mg/kg, p.o.) effectively reversed the cognitive decline in OVX mice, measured by the novel object recognition and Y-maze tests, similar to that in the positive control group. Additionally, it alleviated anxiety- and depressive-like behaviors, as evaluated by the elevated plus-maze test, splash test, and forced swimming test. Paeonol restored GPR30 expression levels in the prefrontal cortex and hippocampus, mirroring the effects of E2 administration. Furthermore, it reversed the reduced expression levels of the PI3K-Akt-mTOR signaling pathway in the prefrontal cortex and hippocampus and increased BDNF expression in the hippocampus of OVX mice., Conclusion: This research suggests that paeonol would be beneficial for alleviating PMS-associated cognitive impairment, anxiety and depression., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The essential Golgi protein Sly1 is a member of the Sec1/mammalian Unc-18 (SM) family of SNARE chaperones. Sly1 was originally identified through remarkable gain-of-function alleles that bypass requirements for diverse vesicle tethering factors. Employing genetic analyses and chemically defined reconstitutions of ER-Golgi fusion, we discovered that a loop conserved among Sly1 family members is not only autoinhibitory but also acts as a positive effector. An amphipathic lipid packing sensor (ALPS)-like helix within the loop directly binds high-curvature membranes. Membrane binding is required for relief of Sly1 autoinhibition and also allows Sly1 to directly tether incoming vesicles to the Qa-SNARE on the target organelle. The SLY1-20 mutation bypasses requirements for diverse tethering factors but loses this ability if the tethering activity is impaired. We propose that long-range tethers, including Golgins and multisubunit tethering complexes, hand off vesicles to Sly1, which then tethers at close range to initiate trans-SNARE complex assembly and fusion in the early secretory pathway., (© 2024 Duan et al.)

The soft epidermis of mammals derives from the accumulation of keratohyaline granules in the granular layer, before maturing into corneocytes. Main proteins accumulated in the granular layer are pro-filaggrin and filaggrin that determine keratin clumping and later moisturization of the stratum corneum that remains flexible. This soft epidermis allows the high sensitivity of mammalian skin. Presence and thickness of the stratum granulosum varies among different species of mammals and even between different body regions of the same animal, from discontinuous to multilayered. These variations are evident using antibodies for filaggrin, a large protein that share common epitopes among placentals. Here we have utilized filaggrin antibodies (8959 and 466) and an acidic keratin antibody (AK2) for labeling placental, marsupial and monotreme epidermis. AK2 labeling appears mainly to detect K24 keratin, and less likely other acidic keratins. Immunoreactivity for filaggrin is absent in platypus, discontinuous in Echidna and in the tested marsupials. In placentals, it is inconstantly or hardly detected in the thin epidermis of bat, rodents, and lagomorphs with a narrow, mono-stratified and/or discontinuous granular layer. In contrast, where the granular layer is continuous or even stratified, both filaggrin and AK2 antibodies decorate granular cells. The ultrastructural analysis using the AK2 antibody on human epidermis reveals that a weak labeling is associated with keratohyalin granules and filamentous keratins of transitional keratinocytes and corneocytes. This observation suggests that basophilic filaggrin interacts with acidic keratins like K24 and determines keratin condensation into corneocytes of the stratum corneum., Competing Interests: Declaration of Competing Interest I declare no competing/conflict of interest in the MS., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Declining flesh quality has drawn considerable attention in the farmed large yellow croaker (LYC; Larimichthys crocea) industry. Inosine monophosphate (IMP) is the primary flavor substance in aquatic animals. Adenosine monophosphate deaminase 1 (AMPD1) plays a critical role in IMP formation by catalyzing the deamination of AMP to IMP in the purine nucleotide cycle. To further evaluate the correlation between ampd1 mRNA expression levels and IMP content in the LYC muscle tissue, the relevant open reading frame (ORF) of L. crocea (Lcampd1) was cloned, and the IMP content and Lcampd1 mRNA expression in the muscles of LYCs of different sizes were examined. The ORF cDNA of Lcampd1 was 2211 bp in length and encoded a polypeptide of 736 amino acids (AAs). The deduced protein, LcAMPD1, possesses conserved AMPD active regions (SLSTDDP) and shows high homology with AMPD proteins of other teleost fishes. The genomic DNA sequence of Lcampd1 exhibits a high degree of evolutionary conservation in terms of structural organization among species. Phylogenetic analysis of the deduced AA sequence revealed that teleost fish and mammalian AMPD1 were separate from each other and formed a cluster with AMPD3, suggesting that AMPD1 and AMPD3 arose by duplication of a common primordial gene. In healthy LYC, Lcampd1 mRNA was expressed only in the muscle tissue. The IMP content in the muscle of LYCs with different average body weights was measured by high-performance liquid chromatography; the results showed that the IMP content in the muscle of LYCs with greater body weight was significantly higher than that in LYC with lower body weight. Moreover, a similar trend in Lcampd1 expression was observed in these muscle tissues. The Pearson correlation analysis further showed that the Lcampd1 mRNA expression was positively correlated with IMP content in the muscles of different-sized LYCs. These results suggest the potential function of Lcampd1 in determining the IMP content in LYC and provide a theoretical basis for flesh quality improvement, as well as a scientific basis for the development of the molecular breeding of LYC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Molecular oxygen and its thermodynamic transformation drive nearly all life processes. Quantitative measurement and imaging of oxygen in living systems is of fundamental importance for the study of life processes and their aberrations-disease- many of which are affected by hypoxia, or low levels of oxygen. Cancer is among the disease processes profoundly affected by hypoxia. Electron paramagnetic resonance has been shown to provide remarkably accurate images of normal and cancerous tissue. In this review, we emphasize the reactivity of molecular oxygen particularly highlighting the metabolic processes of living systems to store free energy in the reactants. The history of hypoxic resistance of living systems to cytotoxic therapy, particularly radiation therapy is also reviewed. The measurement and imaging of molecular oxygen with pulse spin lattice relaxation (SLR) electron paramagnetic resonance (EPR) is reviewed briefly. This emphasizes the advantages of the spin lattice relaxation based measurement paradigm to reduce the sensitivity of the measurement to the presence of the oxygen sensing probe itself. The involvement of a novel small mammal external beam radiation delivery system is described. This enables an experimental paradigm based on control by radiation of the last resistant clonogen. This is much more specific for tumor cure than growth delay assays which primarily reflects control of tumor cells most sensitive to therapy., (© 2024. The Author(s), under exclusive licence to World Molecular Imaging Society.)

The daily light-dark cycle is a key zeitgeber (time cue) for entraining an organism's biological clock, whereby light sensing by retinal photoreceptors, particularly intrinsically photosensitive retinal ganglion cells, stimulates the suprachiasmatic nucleus of the hypothalamus, a central pacemaker that in turn orchestrates the rhythm of peripheral metabolic activities. Non-rhythmic effects of light on metabolism have also been long known, and their transduction mechanisms are only beginning to unfold. Here, we summarize emerging evidence that, in mammals, light exposure or deprivation profoundly affects glucose homeostasis, thermogenesis and other metabolic activities in a clock-independent manner. Such light regulation could involve melanopsin-based, intrinsically photosensitive retinal ganglion cell-initiated brain circuits via the suprachiasmatic nucleus of the hypothalamus and other nuclei, or direct stimulation of opsins expressed in the hypothalamus, adipose tissue, blood vessels and skin to regulate sympathetic tone, lipolysis, glucose uptake, mitochondrial activation, thermogenesis, food intake, blood pressure and melanogenesis. These photic signalling events may coordinate with circadian-based mechanisms to maintain metabolic homeostasis, with dysregulation of this system underlying metabolic diseases caused by aberrant light exposure, such as environmental night light and shift work., (© 2024. Springer Nature Limited.)

The stress-inducible mammalian heat shock protein Hsp70 and its bacterial orthologue DnaK are highly conserved molecular chaperones and a crucial part of the machinery responsible for protein folding and homeostasis. Hsp70 is a three-domain, 70 kDa protein that cycles between an ATP-bound state in which all three domains are securely coupled into one unit and an ADP-bound state in which they are loosely attached via a flexible interdomain linker. The Hsp70 presents an alluring novel therapeutic target since it is crucial for maintaining cellular proteostasis and is particularly crucial to cancer cells. We have performed molecular dynamics simulations of the SBD (substrate binding domain) along with the Lid domain in response to experimental efforts to identify small molecule inhibitors that impair the functioning of Hsp70. Our intent has been to characterize the motion of the SBD/Lid allosteric machinery and in, addition, to identify the effect of the PET16 molecule on this motion. Interestingly, we noticed the opening of the entire Lid domain in the apo-form of the dimer. The configuration of the open structure was very different from previously published structures (PDB 4JN4) of the open and docked conformation of the ATP bound form. MD simulations revealed the Lid to be capable of far greater dynamical excursions than has been anticipated by experimental structural biology. This is of value in future drug discovery efforts targeted to modulating Hsp70 activity. The PET16 molecule appears to be weakly bound and its effect on the dynamics of the complex is yet to be elucidated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

A vast array of challenging environments are inhabited by mammals, such as living in confined spaces where oxygen levels are likely to be low. Species can exhibit adaptations in basal metabolic rate (BMR) to exploit such unique niches. In this study we use 801 species to determine the relationship between BMR and burrow use in mammals. We included pre-existing data for mammalian BMR and 16 life history traits. Overall, mammalian BMR is dictated primarily by environmental ambient temperature. There were no significant differences in BMR of terrestrial, semi-fossorial and fossorial mammals, suggesting that species occupying a subterranean niche do not exhibit baseline metabolic costs on account of their burrowing lifestyle. Fossorial mammals likely show instantaneous metabolic responses to low oxygen in tunnels, rather than exhibit adaptive long-term responses in their BMR., (© 2024. The Author(s).)

As in most cells, intracellular pH regulation is fundamental for sperm physiology. Key sperm functions like swimming, maturation, and a unique exocytotic process, the acrosome reaction, necessary for gamete fusion, are deeply influenced by pH. Sperm pH regulation, both intracellularly and within organelles such as the acrosome, requires a coordinated interplay of various transporters and channels, ensuring that this cell is primed for fertilization. Consistent with the pivotal importance of pH regulation in mammalian sperm physiology, several of its unique transporters are dependent on cytosolic pH. Examples include the Ca 2+ channel CatSper and the K + channel Slo3. The absence of these channels leads to male infertility. This review outlines the main transport elements involved in pH regulation, including cytosolic and acrosomal pH, that participate in these complex functions. We present a glimpse of how these transporters are regulated and how distinct sets of them are orchestrated to allow sperm to fertilize the egg. Much research is needed to begin to envision the complete set of players and the choreography of how cytosolic and organellar pH are regulated in each sperm function.

The key postulate of the prion paradigm is that some proteins can take on unconventional conformations and pass these conformations to newly synthesized protein molecules with the same primary structure [...].

Background: The role of gut microbiota in human health has been intensively studied and more recently shifted from emphasis on composition towards function. Function is partly mediated through formed metabolites. Short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate as well as their branched analogues represent major products from gut fermentation of dietary fibre and proteins, respectively. Robust and high-throughput analysis of SCFAs in small volume blood samples have proven difficult. Major obstacles come from the ubiquitous presence of SCFAs that leads to contaminations and unstable analytical results because of the high volatility of these small molecules. Comprehensive and comparable data on the variation of SCFAs in blood samples from different blood matrices and mammal species including humans is lacking. Therefore, our aim was to develop and evaluate a stable and robust method for quantitation of 8 SCFAs and related fermentation products in small volume blood plasma samples and to investigate their variation in humans and different animal species., Results: Derivatization was a successful approach for measurement of SCFAs in biological samples but quenching of the derivatization reaction was crucial to obtain long-term stability of the derivatized analytes. In total 9 compounds (including succinic acid) were separated in 5 min. The method was linear over the range 0.6-3200 nM formic (FA), acetic (AA), 0.3-1600 nM propionic (PA), and 0.16-800 nM for butyric (BA)-, isobutyric (IBA)-, valeric (VA)-, isovaleric (IVA)-, succinic (SA) and caproic acid (CA). The precision ranged ≤12 % within days and ≤28 % between days (except for CA and VA) in three different plasma quality control (QC) samples (29 batches analyzed over 3 months). The extraction recovery was on average 94 % for the different SCFAs. Typical interquartile range (IQR) concentrations (μM) of SCFAs in human plasma samples were 168 μM (FA), 64 μM (AA), 2.2 μM (PA), 0.54 μM (BA), 0.66 μM (IBA), 0.18 μM (VA), 0.40 μM (IVA), and 0.34 μM (CA). In total, 55 samples per batch/day were successfully analyzed and in total 5380 human plasma samples measured over a 3-year timespan., Significance: The developed UHPLC-MS based method was suitable for measuring SCFAs in small blood volume samples and enabled robust quantitative data., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Milk oligosaccharides (MOs), complex carbohydrates prevalent in human breast milk, play a vital role in infant nutrition. Serving as prebiotics, they inhibit pathogen adherence, modulate the immune system, and support newborn brain development. Notably, MOs demonstrate significant variations in concentration and composition, both across different species and within the same species. These characteristics of MOs lead to several compelling questions: (i) What distinct beneficial functions do MOs offer and how do the functions vary along with their structural differences? (ii) In what ways do MOs in human milk differ from those in other mammals, and what factors drive these unique profiles? (iii) What are the emerging applications of MOs, particularly in the context of their incorporation into infant formula? This review delves into the structural characteristics, quantification methods, and species-specific concentration differences of MOs. It highlights the critical role of human MOs in infant growth and their potential applications, providing substantial evidence to enhance infant health and development., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Intestinal development takes places in two phases, the initial formation of neonatal (mammals)/larval (anurans) intestine and its subsequent maturation into the adult form. This maturation occurs during postembryonic development when plasma thyroid hormone (T3) level peaks. In anurans such as the highly related Xenopus laevis and Xenopus tropicalis, the larval/tadpole intestine is drastically remodeled from a simple tubular structure to a complex, multi-folded adult organ during T3-dependent metamorphosis. This involved complete degeneration of larval epithelium via programmed cell death and de novo formation of adult epithelium, with concurrent maturation of the muscles and connective tissue. Here, we will summarize our current understanding of the underlying molecular mechanisms, with a focus on more recent genetic and genome-wide studies., Competing Interests: Declaration of competing interest There is nothing to declare., (Published by Elsevier B.V.)

Fenvalerate (FEN), a type II pyrethroid pesticide, finds extensive application in agriculture, graziery and public spaces for pest control, resulting in severe environmental pollution. As an environmental endocrine disruptor with estrogen-like activity, exposure to FEN exhibited adverse effects on ovarian functions. Additionally, the presence of the metabolite of FEN in women's urine shows a positive association with the risk of primary ovarian insufficiency (POI). In mammals, the primordial follicle pool established during the early life serves as a reservoir for storing all available oocytes throughout the female reproductive life. The initial size of the primordial follicle pool and the rate of its depletion affect the occurrence of POI. Nevertheless, there is very limited research about the impact of FEN exposure on primordial folliculogenesis. In this study, pregnant mice were orally administrated with 0.2, 2.0 and 20.0 mg/kg FEN from 16.5 to 18.5 days post-coitus (dpc). Ovaries exposed to FEN exhibited the presence of large germ-cell cysts that persist on 1 days post-parturition (1 dpp), followed by a significant reduction in the total number of oocytes in pups on 5 dpp. Moreover, the levels of m6A-RNA and its associated proteins METTL3 and YTHDF2 were significantly increased in the ovaries exposed to FEN. The increased YTHDF2 promoted the assembly of the cytoplasmic processing bodies (P-body) in the oocytes, accompanied with altered expression of transcripts. Additionally, when YTHDF2 was knocked-down in fetal ovary cultures, the primordial folliculogenesis disrupted by FEN exposure was effectively restored. Further, the female offspring exposed to FEN displayed ovarian dysfunctions reminiscent of POI in early adulthood, characterized by decreases in ovarian coefficient and female hormone levels. Therefore, the present study revealed that exposure to FEN during late pregnancy disrupted primordial folliculogenesis by YTHDF2-mediated P-body assembly, causing enduring adverse effects on female fertility., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The comparative studies of aging have established a negative correlation between Gompertz postnatal growth constant and maximum lifespan across mammalian species, but the underlying physiological mechanism remains unclear. This study shows that the Gompertz growth constant can be decomposed into two energetic components, mass-specific metabolic rate and the energetic cost of biosynthesis, and that after controlling the former as a confounder, the negative correlation between growth constant and lifespan still exists due to a 100-fold variation in the latter, revealing that the energetic cost of biosynthesis is a link between growth and longevity in mammals. Previously, the energetic cost of biosynthesis has been thought to be a constant across species and therefore was not considered a contributor to the variation in any life history traits, such as growth and lifespan. This study employs a recently proposed model based on energy conservation to explain the physiological effect of the variation in this energetic cost on the aging process and illustrates its role in linking growth and lifespan. The conventional life history theory suggested a tradeoff between growth and somatic maintenance, but the findings in this study suggest that allocating more energy to biosynthesis may enhance the somatic maintenance and extend lifespan and, hence, reveal a more complex nature of the tradeoff., Competing Interests: Competing interests statement:The author declares no competing interest.

The 2,4-Dichlorophenoxyacetic acid (2,4-D) is a low-cost herbicide to eradicate broadleaf weeds. Since the development of 2,4-D resistant transgenic crops, it has been described as one of the most widely distributed pollutants in the world, increasing concern about its environmental impacts. This study aimed to elucidate the antioxidant system response in animals exposed to 2,4-D by different routes of exposure. It focused on determining if tissue, phylogenetic group, and herbicide formulation would influence the antioxidant mechanisms. A careful literature search of Scopus, WoS, and Science Direct retrieved 6983, 24,098, and 20,616 articles, respectively. The dataset comprised 390 control-treatment comparisons and included three routes of exposure: transgenerational, oral, and topical. The data set for transgenerational and oral exposure revealed oxidative stress through a decrease in enzymatic activities and the level of molecules of the antioxidant system. In contrast, topical exposure increased the oxidative stress. Tissue-specific analyses revealed that the transgenerational effects reduced hepatic catalase (CAT) activity. Oral exposure caused a variety of effects, including increased CAT activity in the prostate and decreased activity in various tissues. Mammals predominate in the transgenerational and oral groups, showing a significantly reduced activity of the antioxidant system. In contrast, in the topical exposure, an increased activity of oxidative stress biomarkers was observed in fish, earthworms, and mollusks. The effects of the 2,4-D formulation on oxidative stress responses showed significant differences between pure and commercial formulations, with oral exposure resulting in decreased activity and topical exposure increasing responses. In summary, orally exposed animals exhibited a clear decrease in enzyme activities, transgenerational exposure elicited tissue-specific prompted biochemical reductions, and topical exposure induced increased responses, emphasizing the need for unbiased exploration of the effects of 2,4-D on biomarkers of oxidative stress while addressing publication bias in oral and topical datasets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Invertebrates are primary contributors to fluxes of nutrients, energy, and contaminants in terrestrial food webs, but the trophodynamic of contaminants in invertebrate food chains is not fully understood. In this study, occurrence and biomagnification of persistent organic pollutants (POPs) were assessed in detritivorous, phytophagous, and predatory invertebrate food chains. Detritivorous species (earthworm and dung beetle) have higher concentrations of POPs than other species. Different composition patterns and biomagnification factors (BMFs) of POPs were observed for invertebrate species. Negative correlations were found between BMFs and log K OW of POPs for detritivorous and most phytophagous species. In contrast, parabolic relationships between BMFs and log K OW were observed in snails and predatory species, possibly attributed to the efficient digestion and absorption of diet and POPs for them. Bioenergetic characteristics are indicative of the biomagnification potential of POPs in terrestrial wildlife, as suggested by the significant and positive correlation between basal metabolic rates (BMRs) and BMFs of BDE 153 for invertebrates, amphibians, reptiles, birds, and mammals. The estimations of dietary exposure suggest that the terrestrial predators, especially feeding on the underground invertebrates, could be exposed to high level POPs from invertebrates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

JM-20 is a 1,5-benzodiazepine compound fused to a dihydropyridine fraction with different pharmacological properties. However, its potential toxic effects on blood cells have not yet been reported. Thus, the present study aimed to investigate, for the first time, the possible cytotoxicity of JM-20 through cell viability, cell cycle, morphology changes, reactive species (RS) to DCFH-DA, and lipid peroxidation in human leukocytes, its hemolytic effect on human erythrocytes, and its potential DNA genotoxicity using plasmid DNA in vitro. Furthermore, the compound's ability to reduce the DPPH radical was also measured. Human blood was obtained from healthy volunteers (30 ± 10 years old), and the leukocytes or erythrocytes were immediately isolated and treated with different concentrations of JM-20. A cytoprotective effect was exhibited by 10 μM JM-20 against 1 mM tert-butyl hydroperoxide (t-but-OOH) in the leukocytes. However, the highest tested concentrations of the compound (20 and 50 μM) changed the morphology and caused a significant decrease in the cell viability of leukocytes (p < 0.05, in comparison with Control). All tested concentrations of JM-20 also resulted in a significant increase in intracellular RS as measured by DCFH-DA in these cells (p < 0.05, in comparison with Control). On the other hand, the results point out a potent antioxidant effect of JM-20, which was similar to the classical antioxidant α-tocopherol. The IC 50 value of JM-20 against the lipid peroxidation induced by (FeII) was 1.051 μM ± 0.21, while the IC 50 value of α-tocopherol in this parameter was 1.065 μM ± 0.34. Additionally, 50 and 100 μM JM-20 reduced the DPPH radical in a statistically similar way to the 100 μM α-tocopherol (p < 0.05, in comparison with the control). No significant hemolysis in erythrocytes, no cell cycle changes in leukocytes, and no genotoxic effects in plasmid DNA were induced by JM-20 at any tested concentration. The in silico pharmacokinetic and toxicological properties of JM-20, derivatives, and nifedipine were also studied. Here, our findings demonstrate that JM-20 and its putative metabolites exhibit similar characteristics to nifedipine, and the in vitro and in silico data support the low toxicity of JM-20 to mammals., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Microbial exopolysaccharides (EPSs) are traditionally known as prebiotics that foster colon health by serving as microbiota nutrients, while remaining undigested in the small intestine. However, recent findings suggest that α-glucan structures in EPS, with their varied α-linkage types, can be hydrolyzed by mammalian α-glucosidases at differing rates. This study explores α-glucan-type EPSs, including dextran, alternan, and reuteran, assessing their digestive properties both in vitro and in vivo. Notably, while fungal amyloglucosidase - a common in vitro tool for carbohydrate digestibility analysis - shows limited efficacy in breaking down these structures, mammalian intestinal α-glucosidases can partially degrade them into glucose, albeit slowly. In vivo experiments with mice revealed that various EPSs elicited a significantly lower glycemic response (p < 0.05) than glucose, indicating their nature as carbohydrates that are digested slowly. This leads to the conclusion that different α-glucan-type EPSs may serve as ingredients that attenuate post-prandial glycemic responses. Furthermore, rather than serving as mere dietary fibers, they hold the potential for blood glucose regulation, offering new avenues for managing obesity, Type 2 diabetes, and other related-chronic diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The protective action of melatonin (MLT) against the harmful effects of cadmium (Cd) on testicular activity in rats has been documented previously; however, the involved molecular mechanisms have yet to be elucidated. Herein, we investigate the involvement of the mammalian target of rapamycin (mTOR) on the ability of MLT to counteract the damage induced by Cd on the rat testicular activity. Our study confirmed that Cd has harmful effects on the testes of rats and the protective action exerted by MLT. We reported, for the first time, that the addition of rapamycin (Rapa), a specific mTOR inhibitor, to animals co-treated with Cd and MLT completely abolished the beneficial effects exerted by MLT, indicating that the mTOR pathway partially modulates its helpful effects on Cd testicular toxicity. Interestingly, Rapa-alone treatment, provoking mTOR inhibition, produced altered morphological parameters, increased autophagy of germ and somatic cells, and reduced serum testosterone concentration. In addition, mTOR inhibition also reduced protein levels of markers of steroidogenesis (3β-Hydroxysteroid dehydrogenase) and blood-testis barrier integrity (occludin and connexin 43). Finally, Rapa altered sperm parameters as well as the ability of mature spermatozoa to perform a proper acrosome reaction. Although further investigation is needed to better clarify the molecular pathway involved in MLT action, we confirm that MLT alleviating Cd effects can be used as a supplement to enhance testicular function and improve male gamete quality., (© 2024 Wiley Periodicals LLC.)

This study aimed to investigate the effects of exercise on muscle fiber conversion, muscle development and meat quality in the biceps femoris (BF) muscle of Sunit sheep. Twelve Sunit sheep with similar body weight were divided into two groups: control group (C group) and exercise group (E group), E group lambs underwent 6 km of exercise training per day for 90 d. The findings revealed that compared with the C group, exercise training enhanced the expression of MyHC IIa mRNA, decreased the number ratio of type IIB muscle fibers and the expression of MyHC IIb mRNA (P < 0.05). Furthermore, the E group lamb displayed higher creatine kinase (CK) activity, and lactic acid levels (P < 0.05), while glycogen content and lactic dehydrogenase (LDH) activity showed opposite trends (P < 0.05). Exercise significantly up-regulated the mRNA expression of AMP-activated protein kinase α1 (AMPKα1), sirtuin1 (SIRT1), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α), cytochrome c oxidase IV (COX IV), protein kinase B (Akt), mammalian target of rapamycin (mTOR) and p70 Ribosomal S6 Kinase 1 (p70s6k1) (P < 0.05), suggesting exercise promoted muscle fiber conversion by mediating AMPK/PGC-1α pathway, and improved skeletal muscle development via Akt/mTOR pathway. Besides, backfat thickness and pH 45min value in the E group decreased significantly, while the pH 24 , a*, and shear force value increased significantly (P < 0.05). To conclude, this study suggested that exercise training can be used to alter muscle fiber characteristics and muscle development in lamb production., Competing Interests: Declaration of competing interest It is declared that the authors have no competing financial interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Iron protoporphyrin IX (heme) is a redox-active cofactor that is bound in mammalian cells by GAPDH and allocated by a process influenced by physiologic levels of NO. This impacts the activity of many heme proteins including indoleamine dioxygenase-1 (IDO1), a redox enzyme involved in immune response and tumor growth. To gain further understanding we created a tetra-Cys human GAPDH reporter construct (TC-hGAPDH) which after labeling could indicate its heme binding by fluorescence quenching. When purified or expressed in a human cell line, TC-hGAPDH had properties like native GAPDH and heme binding quenched its fluorescence by 45-65%, allowing it to report on GAPDH binding of mitochondrially-generated heme in live cells in real time. In cells with active mitochondrial heme synthesis, low-level NO exposure increased heme allocation to IDO1 while keeping the TC-hGAPDH heme level constant due to replenishment by mitochondria. When mitochondrial heme synthesis was blocked, low NO caused a near complete transfer of the existing heme in TC-hGAPDH to IDO1 in a process that required IDO1 be able to bind the heme and have an active hsp90 present. Higher NO exposure had the opposite effect and caused IDO1 heme to transfer back to TC-hGAPDH. This demonstrated: (i) flow of mitochondrial heme through GAPDH is tightly coupled to target delivery, (ii) NO up- or down-regulates IDO1 activity by promoting a conserved heme exchange with GAPDH that goes in either direction according to the NO exposure level. The ability to drive a concentration-dependent, reversible protein heme exchange is unprecedented and reveals a new role for NO in biology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Regulation of the luminal pH of late endocytic compartments in continuously fed mammalian cells is poorly understood. Using normal rat kidney fibroblasts, we investigated the reversible assembly/disassembly of the proton pumping V-ATPase when endolysosomes are formed by kissing and fusion of late endosomes with lysosomes and during the subsequent reformation of lysosomes. We took advantage of previous work showing that sucrosomes formed by the uptake of sucrose are swollen endolysosomes from which lysosomes are reformed after uptake of invertase. Using confocal microscopy and subcellular fractionation of NRK cells stably expressing fluorescently tagged proteins, we found net recruitment of the V1 subcomplex during sucrosome formation and loss during lysosome reformation, with a similar time course to RAB7a loss. Addition of invertase did not alter mTORC1 signalling, suggesting that the regulation of reversible V-ATPase assembly/disassembly in continuously fed cells differs from that in cells subject to amino acid depletion/refeeding. Using live cell microscopy, we demonstrated recruitment of a fluorescently tagged V1 subunit during endolysosome formation and a dynamic equilibrium and rapid exchange between the cytosolic and membrane bound pools of this subunit. We conclude that reversible V-ATPase assembly/disassembly plays a key role in regulating endolysosomal/lysosomal pH in continuously fed cells.

Melanin and the process of melanin synthesis or melanogenesis have central roles in the immune system of insects, and production of melanin-synthesizing enzymes from their haemocytes may be induced following activation through danger signals. Melanin-containing macrophage-like cells have been extensively studied in amphibians and they are also present in reptiles. In fish, melano-macrophages are especially recognized with respect to melano-macrophage centres (MMCs), hypothesized to be analogues of germinal centres in secondary lymphoid organs of mammals and some birds. Melano-macrophages are in addition present in several inflammatory conditions, in particular melanised focal changes, or black spots, in the musculature of farmed Atlantic salmon, Salmo salar. Melanins are complex compounds that may be divided into different forms which all have the ability to absorb and scatter light. Other functions include the quenching of free radicals and a direct effect on the immune system. According to the common view held in the pigment cell community, vertebrate melanin synthesis with melanosome formation may only occur in cells of ectodermal origin. However, abundant information suggests that also myeloid cells of ectothermic vertebrates may be classified as melanocytes. Here, we discuss these opposing views and review relevant literature. Finally, we review the current status on the research concerning melanised focal muscle changes that represent the most severe quality problem in Norwegian salmon production, but also other diseases where melano-macrophages play important roles., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Autophagosomes are double-membraned vesicles that engulf cytoplasmic contents, which are ultimately degraded after autophagosome-lysosome fusion. The prevailing view, largely inferred from EM-based studies, was that mammalian autophagosomes evolved from disc-shaped precursors that invaginated and then were closed at the single opening. Many site(s) of origin of these precursors have been proposed. Using superresolution structured illumination microscopy and electron microscopy, we find that mammalian autophagosomes derive from finger-like outgrowths from the recycling endosome. These "fingers" survey a large cell volume and then close into a "fist" and the openings are sealed in an ESCRT-dependent fashion, while the precursors are still attached to the recycling endosome. We call this transient recycling endosome-attached, closed, autophagic structure an "autophago-dome". DNM2-dependent scission of the autophago-dome from the recycling endosomes liberates free autophagosomes from this compartment. These data reveal unexpected morphologies of autophagosome precursors and raise new questions about the control of this process.

Chicken single-chain fragment variable (IgY-scFv) is a functional fragment and an emerging development in genetically engineered antibodies with a wide range of biomedical applications. However, scFvs have considerably shorter serum half-life due to the absence of antibody Fc region compared with the full-length antibody, and usually requires continuous intravenous administration for efficacy. A promising approach to overcome this limitation is to fuse scFv with immunoglobulin G (IgG) Fc region, for better recognition and mediation by the neonatal Fc receptor (FcRn) in the host. In this study, engineered mammalian ΔFc domains (CH2, CH3, and intact Fc region) were fused with anti-canine parvovirus-like particles avian IgY-scFv to produce chimeric antibodies and expressed in the HEK293 cell expression system. The obtained scFv-CH2, scFv-CH3, and scFv-Fc can bind with antigen specifically and dose-dependently. Surface plasmon resonance investigation confirmed that scFv-CH2, scFv-CH3, and scFv-Fc had different degrees of binding to FcRn, with scFv-Fc showing the highest affinity. scFv-Fc had a significantly longer half-life in mice compared with the unfused scFv. The identified ΔFcs are promising for the development of engineered Fc-based therapeutic antibodies and proteins with longer half-lives. The avian IgY-scFv-mammalian IgG Fc region opens up new avenues for antibody engineering, and it is a novel strategy to enhance the rapid development and screening of functional antibodies in veterinary and human medicine., (© 2024 John Wiley & Sons Ltd.)

DNA N 6 -methyladenine (6 mA) has recently been discovered as a novel DNA modification in animals and plants. In mammals, AlkB homolog 1 (ALKBH1) has been identified as a DNA 6 mA demethylase. ALKBH1 tightly controls the DNA 6 mA methylation level of mammalian genomes and plays important role in regulating gene expression. DNA 6 mA methylation has also been reported to exist in plant genomes, however, the plant DNA 6 mA demethylases and their function remain largely unknown. Here we identify homologs of ALKBH1 as DNA 6 mA demethylases in Arabidopsis. We discover that there are four homologs of ALKBH1, AtALKBH1A, AtALKBH1B, AtALKBH1C and AtALKBH1D, in Arabidopsis. In vitro enzymatic activity studies reveal that AtALKBH1A and 1D can efficiently erase DNA 6 mA methylation. Loss of function of AtALKBH1A and AtALKBH1D causes elevated DNA 6 mA methylation levels in vivo. atalkbh1a/1d mutant displays delayed seed gemination. Based on our RNA-seq data, we find some regulators of seed gemination are dysregulated in atalkbh1a/1d, and the dysregulation is correlated with changes of DNA 6 mA methylation levels. This study identifies plant DNA 6 mA demethylases and reports the function of DNA 6 mA methylation in regulating seed germination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The membrane-abundant NCX proteins mediate an electrogenic ion exchange (3Na + :1Ca 2+ ) in the Ca 2+ -exit or Ca 2+ -entry mode. The structurally related isoform/splice variants of NCX are expressed in a tissue-specific manner to shape Ca 2+ signalling/homeostasis in diverse cell types. The lack of mammalian NCX structure hampered the functional and regulatory resolution of tissue-specific NCX variants and their pharmacological targeting. Recently unveiled Cryo-EM structures of human cardiac NCX1.1[1] and kidney NCX1.3[2] provide new opportunities for resolving structure/functional divergences among NCX variants and their pharmacological targeting., Competing Interests: Declaration of competing interest The author declares no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Primary cilia are rod-like sensory organelles that protrude from the surface of most mammalian cells, including the cells of the islet, and mounting evidence supports important roles of these structures in the regulation of beta cell function and insulin secretion. The sensory abilities of the cilium arise from local receptor activation that is coupled to intrinsic signal transduction, and ciliary signals can propagate into the cell and influence cell function. Here, we review recent advances and studies that provide insights into intra-islet cues that trigger primary cilia signalling; how second messenger signals are generated and propagated within cilia; and how ciliary signalling affects beta cell function. We also discuss the potential involvement of primary cilia and ciliary signalling in the development and progression of type 2 diabetes, identify gaps in our current understanding of islet cell cilia function and provide suggestions on how to further our understanding of this intriguing structure., (© 2024. The Author(s).)

Following ingestion of fruits, vegetables and derived products, (poly)phenols that are not absorbed in the upper gastrointestinal tract pass to the colon, where they undergo microbiota-mediated ring fission resulting in the production of a diversity of low molecular weight phenolic catabolites, which appear in the circulatory system and are excreted in urine along with their phase II metabolites. There is increasing interest in these catabolites because of their potential bioactivity and their use as biomarkers of (poly)phenol intake. Investigating the fate of dietary (poly)phenolics in the colon has become confounded as a result of the recent realisation that many of the phenolics appearing in biofluids can also be derived from the aromatic amino acids, l-phenylalanine and l-tyrosine, and to a lesser extent catecholamines, in reactions that can be catalysed by both colonic microbiota and endogenous mammalian enzymes. The available evidence, albeit currently rather limited, indicates that substantial amounts of phenolic catabolites originate from phenylalanine and tyrosine, while somewhat smaller quantities are produced from dietary (poly)phenols. This review outlines information on this topic and assesses procedures that can be used to help distinguish between phenolics originating from dietary (poly)phenols, the two aromatic amino acids and catecholamines., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.None, (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The in vitro fertilization (IVF) is the first choice of infertile couples worldwide to plan for conception. Besides having a significant advancement in IVF procedure, the success rate is still poor. Although several approaches have been tested to improve IVF protocol, minor changes in culture conditions, physical factors and/or drug treatment generate reactive oxygen species (ROS) in oocytes. Due to large size and huge number of mitochondria, oocyte is more susceptible towards ROS-mediated signalling under in vitro culture conditions. Elevation of ROS levels destabilize maturation promoting factor (MPF) that results in meiotic exit from diplotene as well as metaphase-II (M-II) arrest in vitro. Once meiotic exit occurs, these oocytes get further arrested at metaphase-I (M-I) stage or metaphase-III (M-III)-like stage under in vitro culture conditions. The M-I as well as M-III arrested oocytes are not fit for fertilization and limits IVF outcome. Further, the generation of excess levels of ROS cause oxidative stress (OS) that initiate downstream signalling to initiate various death pathways such as apoptosis, autophagy, necroptosis and deteriorates oocyte quality under in vitro culture conditions. The increase of cellular enzymatic antioxidants and/or supplementation of exogenous antioxidants in culture medium protect ROS-induced deterioration of oocyte quality in vitro. Although a growing body of evidence suggests the ROS and OS-mediated deterioration of oocyte quality in vitro, their downstream signalling and related mechanisms remain poorly understood. Hence, this review article summarizes the existing evidences concerning ROS and OS-mediated downstream signalling during deterioration of oocyte quality in vitro. The use of various antioxidants against ROS and OS-mediated impairment of oocyte quality in vitro has also been explored in order to increase the success rate of IVF during assisted reproductive health management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this review article., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Circular RNAs are highly enriched in the synapses of the mammalian brain and play important roles in neurological function by acting as molecular sponges of microRNAs. circAnk3 is derived from the 11th intron of the ankyrin-3 gene, Ank3, a strong genetic risk factor for neuropsychiatric disorders; however, the function of circAnk3 remains elusive. In this study, we investigated the function of circAnk3 and its downstream regulatory network for target genes in the hippocampus of mice., Methods: The DNA sequence from which circAnk3 is generated was modified using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/Cas9) technology, and neurobehavioral tests (anxiety and depression-like behaviors, social behaviors) were performed in circAnk3 +/- mice. A series of molecular and biochemical assays were used to investigate the function of circAnk3 as a microRNA sponge and its downstream regulatory network for target genes., Results: circAnk3 +/- mice exhibited both anxiety-like behaviors and social deficits. circAnk3 was predominantly located in the cytoplasm of neuronal cells and functioned as a miR-7080-3p sponge to regulate the expression of Iqgap1. Inhibition of miR-7080-3p or restoration of Iqgap1 in the hippocampus ameliorated the behavioral deficits of circAnk3 +/- mice. Furthermore, circAnk3 deficiency decreased the expression of the NMDA receptor subunit GluN2a and impaired the structural plasticity of dendritic synapses in the hippocampus., Conclusions: Our results reveal an important role of the circAnk3/miR-7080-3p/IQGAP1 axis in maintaining the structural plasticity of hippocampal synapses. circAnk3 might offer new insights into the involvement of circular RNAs in neuropsychiatric disorders., (Copyright © 2023 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Peroxisomes are highly plastic organelles that are involved in several metabolic processes, including fatty acid oxidation, ether lipid synthesis and redox homeostasis. Their abundance and activity are dynamically regulated in response to nutrient availability and cellular stress. Damaged or superfluous peroxisomes are removed mainly by pexophagy, the selective autophagy of peroxisomes induced by ubiquitylation of peroxisomal membrane proteins or ubiquitin-independent processes. Dysregulated pexophagy impairs peroxisome homeostasis and has been linked to the development of various human diseases. Despite many recent insights into mammalian pexophagy, our understanding of this process is still limited compared to our understanding of pexophagy in yeast. In this Cell Science at a Glance article and the accompanying poster, we summarize current knowledge on the control of mammalian pexophagy and highlight which aspects require further attention. We also discuss the role of ubiquitylation in pexophagy and describe the ubiquitin machinery involved in regulating signals for the recruitment of phagophores to peroxisomes., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. Published by The Company of Biologists Ltd.)

Gonadotropin-inhibitory hormone (GnIH) was the first reported hypothalamic neuropeptide inhibiting reproduction in vertebrates. Since its discovery in the quail brain, its orthologs have been identified in a variety of vertebrate species and even protochordates. Depending on the species, the GnIH precursor polypeptides comprise two, three or four mature peptides of the RFamide family. It has been well documented that GnIH inhibits reproduction at the brain-pituitary-gonadal levels and participates in metabolism, stress response, and social behaviors in birds and mammals. However, most studies in fish have mainly been focused on the physiological roles of GnIH in the control of reproduction and results obtained are in some cases conflicting, leaving aside its potential roles in the regulation of other functions. In this manuscript we summarize the information available in fish with respect to the structural diversity of GnIH peptides and functional roles of GnIH in reproduction and other physiological processes. We also highlight the molecular mechanisms of GnIH actions on target cells and possible interactions with other neuroendocrine factors., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)