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Duckweeds (Spirodela polyrrhiza) are free-floating macrophytes that grow profusely in nutrient-rich waters. Under ideal conditions, they exhibit a rapid growth rate and can absorb a substantial amount of nutrients, macromolecules, and pollutants from bodies of water. Zinc oxide nanoparticles (ZnO NPs) synthesized from plant extracts, particularly under stress conditions, have opened new research avenues in the field of nanotechnology. Under salinity stress, the accumulation of flavonoids in duckweeds can affect the structure of ZnO NPs, helping researchers ascertain their antimicrobial role. In our study, we exposed mid-log phase duckweed monocultures to 75 mM NaCl in a full-strength Murashige and Skoog medium for 7 days, followed by a 15-day recovery period. We observed significant overexpression of superoxide and hydrogen peroxide as reactive oxygen species. As a result, chlorophyll and certain metabolites were produced in lesser amounts, while flavonoid and phenol content increased by 12% and 8%, respectively. This overproduction persisted up to 10 days into the recovery treatment period but dropped by 8% and 5%, respectively, by the 15th day. The flavonoid coating transformed the NPs into rosette clusters, which exhibited reduced antimicrobial activity against Aeromonas hydrophila, a Gram-negative, fish-pathogenic bacterium. Herein, we discuss potential mechanisms for the conformational transformation of ZnO NPs into finer dimensions in response to NaCl-induced oxidative stress in duckweed. In this study, the azo dye degradation capacity of salinity-treated plants increased as the flavonoid profile became enriched. Zinc oxide nanoparticles, both prior to and after salinity treatment, were found to be efficient in scavenging azo dye and mitigating its toxicity, as evidenced by improved germination, growth, and overall plant morphometry., (© 2024. The Author(s).)

Base metal catalyzed transfer hydrogenation reactions using methanol is highly challenging. Employing a single N-heterocyclic carbene (NHC)-based pincer (CNC)Mn I complex, chemoselective single and double transfer hydrogenation of α, β-unsaturated ketones to saturated ketones or alcohols by utilizing methanol as the hydrogen source is disclosed. The protocol was tolerant towards the selective transfer hydrogenation of C=C or C=O bonds in the presence of several other reducible functional groups and led to the synthesis of several biologically relevant molecules and natural products. Notably, this is the first report of a Mn-catalyzed transfer hydrogenation of carbonyl groups with methanol. Several control experiments, kinetic studies, Hammett studies, and density functional theory (DFT) calculations were carried out to understand the mechanistic details of this catalytic process., (© 2023 Wiley-VCH GmbH.)

Indolyl fragment containing phenanthroline based new ligands and their corresponding Ru(II) complexes were synthesized and fully characterized by various spectroscopic techniques. The catalytic activity of these newly synthesized cyclometalated (NNC)Ru(II) complexes was explored towards the β-methylation of alcohols using methanol. Notably, these complexes displayed superior reactivity compared to various (NNN)Ru(II) complexes. Utilizing this strategy, a wide range of primary, secondary, and aliphatic straight chain alcohols were selectively methylated. This protocol was further employed for the methylation of a few natural products and the gram scale synthesis of β-methylated alcohols. A series of control experiments and kinetic studies were performed to understand the plausible reaction mechanism.

Background: Necrotizing enterocolitis (NEC), a necrotic inflammation of the intestine, represents a major health problem in the very premature infant. Although prevention is difficult, the combination of ingestion of maternal-expressed breastmilk in conjunction with a probiotic provides the best protection. In this study, we establish a mechanism for breastmilk/probiotic protection., Methods: Ultra-high-performance liquid chromatography-tandem mass spectrometry of Bifidobacterium longum subsp. infantis (B. infantis) secretions was used to identify an anti-inflammatory molecule. Indole-3-lactic acid (ILA) was then tested in an established human immature small intestinal cell line, necrotizing colitis enterocytes, and other immature human enteroids for anti-inflammatory effects and to establish developmental function. ILA was also examined in immature and mature enterocytes., Results: We have identified ILA, a metabolite of breastmilk tryptophan, as the anti-inflammatory molecule. This molecule is developmentally functional in immature but not mature intestinal enterocytes; ILA reduces the interleukin-8 (IL-8) response after IL-1β stimulus. It interacts with the transcription factor aryl hydrocarbon receptor (AHR) and prevents transcription of the inflammatory cytokine IL-8., Conclusions: This molecule produced by B. infantis (ATCC No. 15697) interaction with ingested breastmilk functions in a complementary manner and could become useful in the treatment of all at-risk premature infants for NEC if safety and clinical studies are performed.

The synthesis and reactivity of Mn(i) complexes bearing bifunctional ligands comprising both the amine N-H and benzimidazole fragments are reported. Among the various ligands, the N-((1H-benzimidazol-2-yl)methyl)aniline ligand containing Mn(i) complex presented higher reactivity in the transfer hydrogenation (TH) of ketones in 2-propanol. Experimentally, it was established that both the benzimidazole and amine N-H proton played a vital role in the enhancement of the catalytic activity. Utilizing this system a wide range of aldehydes and ketones were reduced efficiently. Notably, the TH of several imines, as well as chemoselective reduction of unsaturated ketones, was achieved in the presence of this catalyst. DFT calculations were carried out to understand the plausible reaction mechanism which disclosed that the transfer hydrogenation reaction followed a concerted outer-sphere mechanism.

A new phosphine-free Co(ii) complex-catalyzed synthesis of various quinoxalines via dehydrogenative coupling of vicinal diols with both o-phenylenediamines and 2-nitroanilines is reported. This complex was also effective for the synthesis of quinolines. The practical aspect of this catalytic system was revealed by the one-pot synthesis of 2-alkylaminoquinolines.

Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability, expressive speech impairment, movement disorder, epilepsy, and a happy demeanor. Children with AS are frequently reported to be poor feeders during infancy and as having gastrointestinal issues such as constipation, reflux, and abnormal food related behaviors throughout their lifetime. To assess the prevalence of gastrointestinal disorders in individuals with AS, we retrospectively analyzed medical records of 120 individuals seen at the Angelman Syndrome Clinic at Massachusetts General Hospital and 43 individuals seen at the University of North Carolina Comprehensive Angelman Clinic. The majority of patients' medical records indicated at least one symptom of gastrointestinal dysfunction, with constipation and gastroesophageal reflux disease (GERD) the most common. Other gastrointestinal issues reported were cyclic vomiting episodes, difficulty swallowing, excessive swallowing, and eosinophilic esophagitis. Upper gastrointestinal symptoms such as GERD, swallowing difficulties, cyclic vomiting, and eosinophilic esophagitis were more common in those with deletions and uniparental disomy, likely related to the involvement of multiple genes and subsequent hypotonia. The frequency of constipation is consistent among all genetic subtypes while early feeding issues appear to mainly affect those with deletions. Caregivers and healthcare providers should be aware of the high prevalence of these issues, as proper treatment may improve not only gastrointestinal dysfunction but also sleep and behavioral issues., (© 2017 Wiley Periodicals, Inc.)

Objectives: The secreted metabolites of probiotics are cytoprotective to intestinal epithelium and have been shown to attenuate inflammation and reduce gut permeability. The present study was designed to determine the protective effects of probiotic conditioned media (PCM) from Bifidobacterium infantis (BCM) and Lactobacillus acidophilus (LCM) on interleukin (IL)-1β-induced intestinal barrier compromise., Methods: The epithelial barrier was determined by measuring the transepithelial electrical resistance (TER) across a Caco-2 cell monolayer using a Transwell model. The paracellular permeability was determined by fluorescein isothiocyanate-labeled dextran flux. The expression of tight junction (TJ) proteins and nuclear factor-kappa B (NF-κB) p65 were determined using Western blot and the distribution of NF-κB p65 was determined by immunofluorescence staining., Results: BCM and LCM induced a dose-dependent increase in Caco-2 TER after 4 and 24 hours of incubation (P < 0.05). The maximal increase of Caco-2 TER occurred at 4 hours of treatment with a PCM concentration of 15%. Preincubation with BCM and LCM for 4 hours significantly prevented the decrease of Caco-2 TER induced by 24 hours of stimulation with 10 ng/mL IL-1β. BCM and LCM decreased paracellular permeability in both stimulated and unstimulated Caco-2 monolayers (P < 0.05). IL-1β stimulation decreased occludin expression and increased claudin-1 expression in Caco-2 cells (P < 0.05), which was prevented in cells treated with BCM or LCM. The changes of claudin-1 expression in H4 cells were similar to Caco-2 cells in response to PCM treatment and IL-1β stimulation; however, a similar response in occludin was not demonstrated. The IL-1β-induced nuclear translocation of NF-κB p65 in Caco-2 cells was prevented by pretreatment with both PCMs., Conclusions: BCM and LCM protected the intestinal barrier against IL-1β stimulation by normalizing the protein expression of occludin and claudin-1 and preventing IL-1β-induced NF-κB activation in Caco-2 cells, which may be partly responsible for the preservation of intestinal permeability.

The therapeutic and preventive application of probiotics for necrotizing enterocolitis (NEC) has been supported by more and more experimental and clinical evidence in which Toll-like receptor 4 (TLR-4) exerts a significant role. In immune cells, probiotics not only regulate the expression of TLR-4 but also use the TLR-4 to modulate the immune response. Probiotics may also use the TLR-4 in immature enterocytes for anti-inflammation. Here we demonstrate that probiotic conditioned media (PCM) from Bifidobacterium longum supp infantis but not isolated organisms attenuates interleukin-6 (IL-6) induction in response to IL-1β by using TLR-4 in a human fetal small intestinal epithelial cell line (H4 cells), human fetal small intestinal xenografts, mouse fetal small intestinal organ culture tissues, and primary NEC enterocytes. Furthermore, we show that PCM, using TLR-4, downregulates the mRNA expression of interleukin-1 receptor-associated kinase 2 (IRAK-2), a common adapter protein shared by IL-1β and TLR-4 signaling. PCM also reduces the phosphorylation of the activator-protein 1 (AP-1) transcription factors c-Jun and c-Fos in response to IL-1β stimulation in a TLR-4-dependent manner. This study suggests that PCM may use TLR-4 through IRAK-2 and via AP-1 to prevent IL-1β-induced IL-6 induction in immature enterocytes. Based on these observations, the combined use of probiotics and anti-TLR-4 therapy to prevent NEC may not be a good strategy., (Copyright © 2016 the American Physiological Society.)

Background: Evidence suggests that excessive inflammation of the immature intestine may predispose premature infants to necrotizing enterocolitis (NEC). We investigated the anti-inflammatory effects of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) in human fetal and adult intestinal epithelial cells (IEC) in primary culture., Methods: Human fetal IEC in culture were derived from a healthy fetal small intestine (H4) or resected small intestine of a neonate with NEC (NEC-IEC). Intestinal cell lines Caco2 and NCM460 in culture were used as models for mature IEC. IEC in culture were pretreated with 100 µmol/l palmitic acid (PAL), DHA, EPA, ARA, or ARA+DHA for 48 h and then stimulated with proinflammatory IL-1β., Results: DHA significantly attenuated IL-1β induced proinflammatory IL-8 and IL-6 protein and mRNA in fetal H4, NEC-IEC, and mature Caco2, NCM460 IEC, compared to control and PAL treatment. DHA downregulated IL-1R1 (IL-1β receptor) and NFk β1 mRNA expression in fetal and adult IEC. ARA had potent anti-inflammatory effects with lower IL-8 and IL-6 (protein and mRNA) in fetal H4 but not in NEC-IEC or adult IEC., Conclusion: The present study provides evidence that DHA and ARA may have important anti-inflammatory functions for prevention of NEC in premature infants.

Combination regimens of Bifidobacterium infantis and Lactobacillus acidophilus have been demonstrated to prevent necrotizing enterocolitis (NEC) in clinical trials. However, the molecular mechanisms responsible for this protective effect are not well understood. Additionally, conditioned media from individual cultures of these two probiotics show strain specific modulation of inflammation using in vitro human intestinal NEC models. Here we report a transcription profiling analysis of gene expression in immature human fetal intestinal epithelial cells (H4 cells) pretreated with conditioned media from B. infantis (BCM) or L. acidophilus (LCM) prior to IL-1β stimulation. Compared with control media, the two probiotic-conditioned media (PCM) treatments altered the expression of hundreds of genes involved in the immune response, apoptosis and cell survival, cell adhesion, the cell cycle, development and angiogenesis. In IL-1β-stimulated cells, PCM treatment decreased the upregulation of genes in the NF-κB activation pathway and downregulated genes associated with extracellular matrix (ECM) remodeling. Compared with LCM, BCM showed more significant modulatory effects on ECM remodeling, reflected by a lower p value. IL-6 and IL-8 production was significantly reduced in IL-1β-stimulated cells pretreated with PCM (p<0.05), which was consistent with their altered gene expression. Western blot analysis showed that compared with IL-1β stimulation alone, PCM treatment attenuated the decrease of cytoplasmic IκBα and NF-κB p65 levels as well as the increase of nuclear NF-κB p65 levels in the stimulated cells (p<0.05). In conclusion, PCM treatment exerted anti-inflammatory effects in immature human fetal enterocytes primarily by modulating genes in the NF-κB signaling and ECM remodeling pathways. Additionally, some components of these signaling pathways, particularly the ECM remodeling pathway, were more profoundly affected by BCM than LCM.

Background: Bacterial contact in utero modulates fetal and neonatal immune responses. Maternal probiotic supplementation reduces the risk of immune-mediated disease in the infant. We investigated the immunomodulatory properties of live Lactobacillus rhamnosus GG and its SpaC pilus adhesin in human fetal intestinal models., Methods: Tumor necrosis factor (TNF)-α mRNA expression was measured by qPCR in a human fetal intestinal organ culture model exposed to live L. rhamnosus GG and proinflammatory stimuli. Binding of recombinant SpaC pilus protein to intestinal epithelial cells (IECs) was assessed in human fetal intestinal organ culture and the human fetal intestinal epithelial cell line H4 by immunohistochemistry and immunofluorescence, respectively. TLR-related gene expression in fetal ileal organ culture after exposure to recombinant SpaC was assessed by qPCR., Results: Live L. rhamnosus GG significantly attenuates pathogen-induced TNF-α mRNA expression in the human fetal gut. Recombinant SpaC protein was found to adhere to the fetal gut and to modulate varying levels of TLR-related gene expression., Conclusion: The human fetal gut is responsive to luminal microbes. L. rhamnosus GG significantly attenuates fetal intestinal inflammatory responses to pathogenic bacteria. The L. rhamnosus GG pilus adhesin SpaC binds to immature human IECs and directly modulates IEC innate immune gene expression.

Necrotizing enterocolitis (NEC) is associated with a high morbidity and mortality in very low birth weight infants. Several hypotheses regarding the pathogenesis of NEC have been proposed but to date no effective treatment is available. Previous studies suggest that probiotic supplementation is protective. We recently reported that probiotic (Bifidobacterium infantis) conditioned medium (PCM) has an anti-inflammatory effect in cultured fetal human intestinal cells (H4) and fetal intestine explants. In this study, we tested in vivo whether PCM protects neonatal mice from developing intestinal inflammation induced by exposure to Cronobacter sakazakii (C. sakazakii), an opportunistic pathogen associated with NEC. We found that infected neonatal mice had a significantly lower body weight than control groups. Infection led to ileal tissue damage including villous rupture, disruption of epithelial cell alignment, intestinal inflammation, apoptotic cell loss, and decreased mucus production. Pretreatment with PCM prevented infection caused decrease in body weight, attenuated enterocyte apoptotic cell death, mitigated reduced mucin production, and maintained ileal structure. Infected ileum expressed reduced levels of IκBα, which could be restored upon pretreatment with PCM. We also observed a nuclear translocation of NF-κB p65 in H4 cells exposed to C. sakazakii, which was prevented in PCM-pretreated cells. Finally, treatment of neonatal mice with PCM prior to infection sustained the capacity of ileal epithelial proliferation. This study suggests that an active component(s) released into the culture medium by B. infantis may prevent ileal damage by a pathogen linked to NEC.

Necrotizing enterocolitis (NEC), an extensive intestinal inflammatory disease of premature infants, is caused, in part, by an excessive inflammatory response to initial bacterial colonization due to the immature expression of innate immune response genes. In a randomized placebo-controlled clinical trial, supplementation of very low birth weight infants with probiotics significantly reduced the incidence of NEC. The primary goal of this study was to determine whether secreted products of these two clinically effective probiotic strains, Bifidobacterium infantis and Lactobacillus acidophilus, prevented NEC by accelerating the maturation of intestinal innate immune response genes and whether both strains are required for this effect. After exposure to probiotic conditioned media (PCM), immature human enterocytes, immature human intestinal xenografts, and primary enterocyte cultures of NEC tissue (NEC-IEC) were assayed for an IL-8 and IL-6 response to inflammatory stimuli. The latter two models were also assayed for innate immune response gene expression. In the immature xenograft, PCM exposure significantly attenuated LPS and IL-1β-induced IL-8 and IL-6 expression, decreased TLR2 mRNA and TLR4 mRNA, and increased mRNA levels of specific negative regulators of inflammation, SIGIRR and Tollip. In NEC-IEC, PCM decreased TLR2-dependent IL-8 and IL-6 induction and increased SIGIRR and Tollip expression. The attenuated inflammatory response with PCM was reversed with Tollip siRNA-mediated knockdown. The anti-inflammatory secreted factor is a 5- to 10-kDa molecule resistant to DNase, RNase, protease, heat stress, and acid exposure. B. infantis-conditioned media showed superior anti-inflammatory properties to that of L. acidophilus in immature human enterocytes, suggesting a strain specificity to this effect. We conclude that PCM promotes maturation of innate immune response gene expression, potentially explaining the protective effects of probiotics in clinical NEC.

Necrotizing enterocolitis (NEC) is a devastating condition characterized by diffuse intestinal inflammation and necrosis in preterm infants. It is the most common gastrointestinal emergency in the neonatal intensive care unit and is associated with significant morbidity and mortality. Primary risk factors include prematurity and low birth weight. Although the pathogenesis of NEC is complex and not entirely understood, it is known that an interplay between immature intestinal immune responses and the process of bacterial colonization is required for the development of this disease., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Necrotizing enterocolitis (NEC) is a common gastrointestinal inflammatory necrosis affecting almost exclusively premature infants usually after oral nutrition has been started, for example, 10 day plus postpartum. Although the pathogenesis is incompletely understood, major risk factors include prematurity and incomplete bacterial colonization. Evidence has been shown that the premature infant because of rapid passage through the birth canal or because of delivery by cesarean section has an inadequate initial ingestion of maternal colonic and vaginal flora and therefore, an inadequate initial colonization with less diversity of bacteria phylla and fewer species of bacteria in the microbiota. As a result, they are more susceptible to environmental pathogens. In addition, prematures have immature intestinal defenses (glycocalyx, tight junctions, innate immune response, etc.) resulting in excessive inflammation in response to luminal stimuli. Recently, we reported that genes mediating the innate inflammatory immune response are developmentally expressed with an increase in toll-like receptors, signaling molecules and transgenic factors and decreased negative regulators of inflammation, which undoubtedly contribute to an excessive inflammatory response. Several clinical studies have suggested that the use of probiotics and ingestion of expressed maternal breast milk containing probiotics can help to stabilize colonization and to reduce the incidence and severity of NEC when given to premature infants at risk. Meta-analyses of multiple small studies strongly suggest a protective effect in the use of probiotics. A multicenter study in Taiwan suggests that Bifidobacteria infantis and Lactobacillus acidophilus in combination may prevent NEC. These meta-analyses suggest that these probiotics should be used in routine care of premature infants. Other clinicians, however, suggest caution, holding out for a single protocol multicenter trial before routine use can be suggested.