Search

Deseeded sunflower is a heterogeneous lignocellulosic biomass that has not been well utilized due to the incomplete understanding of its biological structure. In this study, deseeded sunflower was fractioned into the stalk rind, stalk pith, receptacle, bract, bractlet, leaf blade, and petiole, and their anatomy, cell morphology, and fiber dimension were studied using light microscope, environmental scanning electron microscope, and fiber quality analyzer. The results showed that the major fractions were the stalk rind and receptacle (49.4 wt% and 28.1 wt%, respectively) and each of the other fractions was less than 10 wt% of the total biomass. The pith was only composed of parenchyma tissue, and the other fractions were composed of epidermal, parenchyma, and vascular tissues. The arrangement and number of vascular tissues were different among fractions. The fiber length in the stalk rind was 0.823 mm, the width was 21.3 μm, and the aspect ratio was 38.6. The content of fiber fines in other fractions was higher than 50%, and these fractions should be developed for other uses. Fractionation was judged to be an effective way to achieve high value utilization of deseeded sunflower.

Abstract Airborne viruses are ubiquitous and play critical roles in maintaining ecosystem balance, however, they remain unexplored. Here, it is aimed to demonstrate that highly diverse airborne viromes carry out specific metabolic functions and use different transmission modes under different air quality conditions. A total of 263.5‐Gb data are collected from 13 air samples for viral metagenomic analysis. After assembly and curation, a total of 12 484 viral contigs (1.5–184.2 kb) are assigned to 221 genus‐level clades belonging to 47 families, 19 orders, and 15 classes. The composition of viral communities is influenced by weather conditions, with the main biomarker being Caudoviricetes. The most dominant viruses in these air samples belong to the dsDNA Caudoviricetes (54.0%) and ssDNA Repensiviricetes (31.2%) classes. Twelve novel candidate viruses are identified at the order/family/genus levels by alignment of complete genomes and core genes. Notably, Caudoviricetes are highly prevalent in cloudy and smoggy air, whereas Repensiviricetes are highly dominant in sunny and rainy air. Diverse auxiliary metabolic genes of airborne viruses are mainly involved in deoxynucleotide synthesis, implying their unique roles in atmosphere ecosystem. These findings deepen the understanding of the meteorological impacts on viral composition, transmission mode, and ecological roles in the air that we breathe.

Abstract Earth’s lower mantle is a potential water reservoir. The physical and chemical properties of the region are in part controlled by the Fe3+/ΣFe ratio and total iron content in bridgmanite. However, the water effect on the chemistry of bridgmanite remains unclear. We carry out laser-heated diamond anvil cell experiments under hydrous conditions and observe dominant Fe2+ in bridgmanite (Mg, Fe)SiO3 above 105 GPa under the normal geotherm conditions corresponding to depth > 2300 km, whereas Fe3+-rich bridgmanite is obtained at lower pressures. We further observe FeO in coexistence with hydrous NiAs-type SiO2 under similar conditions, indicating that the stability of ferrous iron is a combined result of H2O effect and high pressure. The stability of ferrous iron in bridgmanite under hydrous conditions would provide an explanation for the nature of the low-shear-velocity anomalies in the deep lower mantle. In addition, entrainment from a hydrous dense layer may influence mantle plume dynamics and contribute to variations in the redox conditions of the mantle.

Psoriasis vulgaris is a chronic dermatological disease with a high global prevalence. It significantly reduces patients' quality of life and is associated with a substantial economic burden. Conventional therapies for mild-to-moderate psoriasis are often associated with insufficient long-term symptomatic relief and side effects. Chinese herbal medicine (CHM) is commonly used for psoriasis management. A CHM formula, namely Fu zheng he fu zhi yang (FZHFZY), has shown promising treatment effects in clinical practice when used as a bath therapy. However, its efficacy and safety has not been evaluated by a rigorous randomized controlled trial (RCT). Therefore, we designed a double-blinded pilot RCT embedded with a qualitative study on CHM formula FZHFZY plus topical urea for mild-to-moderate psoriasis vulgaris to advance the evidence development and practice of CHM external application for psoriasis. This will be a mixed-method design consisting of a pilot RCT and a qualitative study. The pilot RCT is a two-arm, parallel, placebo-controlled, double-blinded trial. Sixty eligible participants will be randomized at a 1:1 ratio to receive eight weeks' treatment of either FZHFZY plus 10% urea cream, or placebo plus 10% urea cream, with 12-week follow-up visits after the treatment phase. The CHM or placebo will be administered externally as a bath therapy. Outcome measures include trial feasibility, efficacy and safety. The primary efficacy outcome will be Psoriasis Area Severity Index (PASI). Secondary efficacy outcomes include Physician Global Assessment, PASI-75, PASI-50, Body Surface Area, Dermatology Life Quality Index, Skindex-16, itch visual analogue scale and relapse. The qualitative study will be conducted to collect participants' feedback on CHM external application and their experience with the pilot RCT. This study will advance the evidence-based clinical practice of using CHM for psoriasis vulgaris and then to support translation of findings into clinical practice in the future. Trial registration number: ChiCTR2200064092.

It is important to understand the mechanism of travel location choices, since the dynamic individual behavior would lead to the evolution of the network. The existing location choice researches usually based on the static and perfect information, and analyzed each step of the travel independently. This research considers the interaction between individuals on a series of trips in the travel chain by incorporating the spatial-temporal bounded rationality estimation. The Indifference Zone and information sharing in the travel process are defined to explore the spatial and temporal sides. A within-day location choice model is developed based on the spatial benefit and temporal cost. The proposed spatial-temporal bounded rationality LSTM model is verified in five cities networks in China, and it shows the 8.65% and 20.30% improvement, respectively, compared to the spatial bounded rationality LSTM models and perfect rationality LSTM models. In addition, the improvement becomes more pronounced when more alternative locations (the largest city improve 31.65%), more serious congestion (improve 27.45%), more complex chain (improve 13.85%), and more stable weight (improve 22.88%). The proposed dynamic decision model with bounded rationality would provide insights for travel chain prediction in the complex urban network.

The dinoflagellate Noctiluca scintillans is a globally distributed bloom-forming species. Previous studies have shown that the primary reason for the frequent occurrence of N. scintillans blooms may be the proliferation of microalgae due to eutrophication, which provides a sufficient source of food. Meanwhile, N. scintillans may release nutrients into the environment, thus affecting the population dynamics of microalgae. Thus, to investigate the interaction between N. scintillans and co-occurring microalgae, this study examined the population dynamics of N. scintillans and their interaction with three representative microalgae species in response to varying nutrient levels. The findings indicate that the growth of N. scintillans is slow when co-cultured with diatom Skeletonema costatum. Moreover, a high density and rapid growth rate of S. costatum may have an inhibitory effect on the growth of N. scintillans. Conversely, the population abundance of N. scintillans increased with the rise in the population density and nutritional level of Heterocapsa steinii (dinoflagellate) and Heterosigma akashiwo (raphidophyceae). Notably, N. scintillans can discharge specific nutrients into the aquatic environment, which can subsequently be assimilated and exploited by H. steinii. Thus, the interaction between the species and population dynamics of plankton, as well as changes in nutrient levels within the ecosystem, played a significant role in influencing the growth and population dynamics of N. scintillans. The mutualistic association between N. scintillans and microalgae may establish a transient closed loop, thereby fostering the sustained proliferation and subsequent expansion of N. scintillans.

Abstract Background Purine nucleosides play essential roles in cellular physiological processes and have a wide range of applications in the fields of antitumor/antiviral drugs and food. However, microbial overproduction of purine nucleosides by de novo metabolic engineering remains a great challenge due to their strict and complex regulatory machinery involved in biosynthetic pathways. Results In this study, we designed an in silico-guided strategy for overproducing purine nucleosides based on a genome-scale metabolic network model in Bacillus subtilis. The metabolic flux was analyzed to predict two key backflow nodes, Drm (purine nucleotides toward PPP) and YwjH (PPP–EMP), to resolve the competitive relationship between biomass and purine nucleotide synthesis. In terms of the purine synthesis pathway, the first backflow node Drm was inactivated to block the degradation of purine nucleotides, which greatly increased the inosine production to 13.98–14.47 g/L without affecting cell growth. Furthermore, releasing feedback inhibition of the purine operon by promoter replacement enhanced the accumulation of purine nucleotides. In terms of the central carbon metabolic pathways, the deletion of the second backflow node YwjH and overexpression of Zwf were combined to increase inosine production to 22.01 ± 1.18 g/L by enhancing the metabolic flow of PPP. By switching on the flux node of the glucose-6-phosphate to PPP or EMP, the final inosine engineered strain produced up to 25.81 ± 1.23 g/L inosine by a pgi-based metabolic switch with a yield of 0.126 mol/mol glucose, a productivity of 0.358 g/L/h and a synthesis rate of 0.088 mmol/gDW/h, representing the highest yield in de novo engineered inosine bacteria. Under the guidance of this in silico-designed strategy, a general chassis bacterium was generated, for the first time, to efficiently synthesize inosine, adenosine, guanosine, IMP and GMP, which provides sufficient precursors for the synthesis of various purine intermediates. Conclusions Our study reveals that in silico-guided metabolic engineering successfully optimized the purine synthesis pathway by exploring efficient targets, which could be applied as a superior strategy for efficient biosynthesis of biotechnological products.

IntroductionGranulomatous mastitis (GM) is a chronic inflammatory breast disease. In recent years, the role of Corynebacterium in GM onset has received more and more attention. This study aims to detect the dominant bacterium in GM patients and analyze the association between clinical characteristics and infectious factors.MethodsIn this study, 88 samples from 44 GM patients, six acute lactation mastitis (ALM) patients, and 25 non-inflammatory breast disease (NIB) patients were divided into a GM pus group, a GM tissue group, an ALM pus group, and a NIB tissue group; then, 16S ribosomal DNA sequencing was used to explore their microbiota. The clinical data of all 44 GM patients were also retrospectively collected and analyzed to determine their relationship with infection.ResultsThe median age of the 44 GM patients was 33 years, and 88.6% of patients had primary-onset cases, while 11.4% were recurrences; additionally, 89.5% of patients were postpartum and 10.5% were nulliparous. The serum prolactin level was abnormal in nine patients (24.3%). Samples from 15 GM patients (34.1%) had a Corynebacterium abundance of >1% (1.08–80.08%), with eight (53.3%) displaying an abundance of >10%. Corynebacterium was the only genus with significant differences between the GM pus group and the other three groups (p < 0.05). Corynebacterium kroppenstedtii was the predominant Corynebacterium species. Among clinical characteristics, a statistical difference in breast abscess formation was observed according to Corynebacterium abundance in Corynebacterium-positive and- negative patients (p < 0.05).DiscussionThis study explored the relationship between Corynebacterium infection and GM, compared the clinical characteristics between Corynebacterium-positive and- negative patients, and provided support for the role of Corynebacterium species-in particular, C. kroppenstedtii-in the pathogenesis of GM. The detection of Corynebacterium can predict GM onset, especially in patients with high prolactin levels or a history of recent lactation.

The dinoflagellate Noctiluca scintillans is a harmful algal species that is globally distributed and poses a certain threat to marine ecosystems. Recent research has shown that the application of algicidal bacteria is a promising method to prevent and control such harmful algal blooms (HABs), given its advantages of safety and efficiency. In this study, a strain of algicidal bacterium LD-B6 with high efficiency against N. scintillans was isolated from the coastal waters of Lianyungang, China. 16S rDNA sequence analysis showed that the strain LD-B6 belongs to the genus Pseudoalteromonas. Furthermore, the algicidal effect of LD-B6 on N. scintillans was investigated. The results showed that strain LD-B6 exerted strong algicidal activity against N. scintillans. After 12 h of bacterial culture addition to algal cultures at a 2% final volume rate, the algicidal activity reached 90.5%, and the algicidal activity of LD-B6 was influenced by the density of N. scintillans. In addition, the algicidal bacterium LD-B6 was found to indirectly lyse algal cells by secreting extracellular compounds. These algicidal compounds were stable, indicating that they are not proteins. Importantly, strain LD-B6 was broadly general, showing varying degrees of lysing effects against five of the six algal species tested. On the basis of the described studies above, the algicidal powder was also initially developed. In summary, the isolated bacterial strain LD-B6 shows the potent algicidal capability to serve as a candidate algicidal bacterium against N. scintillans blooms.

The advancement in technology has changed the workflow and the role of human translator in recent years. The impact from the trend of technology-mediated translation prompted the ratification of technology literacy as a major competence for modern translators. Consequently, teaching of translation technology including but not limited to Computer-aided Translation (CAT) and Machine Translation (MT) became part of comprehensive curricula for translation training programs. However, in many institutions, the teaching of translation technology was haunted by issues such as: narrow scope of curriculum design, outdated technologies, and unbalance between theories and practices in teaching. The study was the pilot evaluation of a tailored course to foster translation trainees’ knowledge and abilities of data science. The course was designed to be a fundamental step toward sophisticated translation technologies. During the pilot evaluation of the 8-week course, 85 students (n = 85) were recruited as participants. The study adopted a mix-method design by employing a survey to investigate student’s level of satisfaction toward the course and focus group discussion to understand students’ attitudes and perceptions of key aspects of the course. By interpreting the results from statistical analysis of the survey (5.39/7) and thematic analysis of the focus group discussion, the course of data science for translators was well received among participants. The evaluation project manifested the feasibility and effectiveness of a translator-oriented data science course.

Abstract The sound velocities of water in the Hugoniot states are investigated by laser shock compression of precompressed water in a diamond anvil cell. The obtained sound velocities in the off-Hugoniot region of liquid water at precompressed conditions are used to test the predictions of quantum molecular dynamics (QMD) simulations and the SESAME equation-of-state (EOS) library. It is found that the prediction of QMD simulations agrees with the experimental data while the prediction of SESAME EOS library underestimates the sound velocities probably due to its improper accounting for the ionization processes.

The ichthyotoxic raphidophyte Heterosigma akashiwo is associated with harmful algal blooms (HABs). Although the influence of H. akashiwo on fish has been reported, little is known of its effects on other marine organisms, such as shellfish. In this study, the physiological and transcriptomic responses of the Asiatic hard clam Meretrix meretrix to H. akashiwo were investigated. The results showed that clam survival was not influenced by H. akashiwo (at a concentration of 2 × 104 cells/mL), and M. meretrix eliminated the alga effectively after 48 h in co-culture. H. akashiwo did not alter the antioxidant capacity of the clams. However, 544 unigenes were found to be differentially expressed between the control and H. akashiwo-treated clams. Interestingly, the significant up-regulation of lysosome-related genes and transport proteins suggested remodeling of the clam metabolism possibly for digestion of H. akashiwo. In summary, our results indicate that the clam M. meretrix can effectively feed on H. akashiwo, and intensification of shellfish farming may be helpful to control and mitigate H. akashiwo blooms.

Abstract Background Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) causes bloody diarrhea and hemolytic-uremic syndrome. EHEC O157 encounters varied microenvironments during infection, and can efficiently adapt to these using the two-component system (TCS). Recently, a functional TCS, RstAB, has been implicated in the regulation of virulence of several bacterial pathogens. However, the regulatory function of RstAB in EHEC O157 is poorly understood. This study aimed at providing insights into the global effects of RstA on gene expression in EHEC O157. Results In the present study, we analyzed gene expression differences between the EHEC O157 wild-type strain and a ΔrstA mutant using RNA-seq technology. Genes with differential expression in the ΔrstA mutant compared to that in the wild-type strain were identified and grouped into clusters of orthologous categories. RstA promoted EHEC O157 LEE gene expression, adhesion in vitro, and colonization in vivo by indirect regulation. We also found that RstA could bind directly to the promoter region of hdeA and yeaI to enhance acid tolerance and decrease biofilm formation by modulating the concentration of c-di-GMP. Conclusions In summary, the RstAB TCS in EHEC O157 plays a major role in the regulation of virulence, acid tolerance, and biofilm formation. We clarified the regulatory function of RstA, providing an insight into mechanisms that may be potential drug targets for treatment of EHEC O157-related infections.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 (O157) is a major foodborne pathogen that causes severe illness in humans worldwide. The genome of O157 contains 177 genomic islands known as O islands (OIs), including Shiga toxin-converting phages (OI-45 and OI-93) and the locus for enterocyte effacement (LEE) pathogenicity island (OI-148). However, most genes in OIs are uncharacterized and code for unknown functions. In this study, we demonstrated, for the first time, that OI-9 encodes a novel transcriptional activator, Z0346 (named OvrB), which is required for bacterial adherence to host cells and LEE gene expression in O157. OvrB directly binds to the promoter region of LEE1 and activates the transcription of ler (encoding a master regulator of LEE genes), which in turn activates LEE1–5 genes to promote O157 adherence. Furthermore, mouse oral infection assays showed that OvrB promotes O157 colonization in the mouse intestine. Finally, OvrB is shown to be a widespread transcriptional activator of virulence genes in other enterohemorrhagic and enteropathogenic Escherichia coli serotypes. Our work significantly expands the understanding of bacterial virulence control and provides new evidence suggesting that horizontally transferred regulator genes mediate LEE gene expression.

Owing to the limitations of printed stereoacuity tests, the effects of luminance and contrast on stereopsis have not yet been sufficiently investigated, despite its important implications in designing stereoacuity measuring instruments, particularly for electronic devices. A stereopsis measurement system was established using two 4 K smartphones and a phoropter to evaluate the effects of luminance and contrast variations on the stereoacuity test. Seventeen young subjects with normal visual acuity and stereopsis were recruited. Two types of test symbols, contour-based and random-dot-based, were used in the experiment. Four series tests were established with different maximum brightness values, including 240 lux, 120 lux, 60 lux, and 30 lux. Each series test contained 19 pages with different contrasts between 95% and 5% and was calculated using the Michelson contrast formula. No significant difference was found for both contour-based and random-dot-based stereograms in any of the contrast groups with different maximum brightness. Similarly, no significant difference was found between contour-based and random-dot-based patterns under different contrasts of above 35%. As the contrast decreased below 30%, the stereopsis was significantly better in the contour-based pattern than in the random-dot-based pattern for some degrees of contrast. The luminance and contrast of the digital display are not critical factors for stereoacuity under normal circumstances. This implies that a standard monitor with a certain 3D technology can be used to measure the stereoacuity threshold without calibrating the luminance and contrast.

ABSTRACT The large intestinal pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 detects host cues to regulate virulence gene expression during colonization and infection. However, virulence regulatory mechanisms of EHEC O157:H7 in the human large intestine are not fully understood. Herein, we identified a virulence-regulating pathway where the PhoQ/PhoP two-component regulatory system senses low magnesium levels and signals to the O island 119-encoded Z4267 (LmiA; low magnesium-induced regulator A), directly activating loci of enterocyte effacement genes to promote EHEC O157:H7 adherence in the large intestine. Disruption of this pathway significantly decreased EHEC O157:H7 adherence in the mouse intestinal tract. Moreover, feeding mice a magnesium-rich diet significantly reduced EHEC O157:H7 adherence in vivo. This LmiA-mediated virulence regulatory pathway is also conserved among several EHEC and enteropathogenic E. coli serotypes; therefore, our findings support the use of magnesium as a dietary supplement and provide greater insights into the dietary cues that can prevent enteric infections. IMPORTANCE Sensing specific gut metabolites is an important strategy for inducing crucial virulence programs by enterohemorrhagic Escherichia coli (EHEC) O157:H7 during colonization and infection. Here, we identified a virulence-regulating pathway wherein the PhoQ/PhoP two-component regulatory system signals to the O island 119-encoded low magnesium-induced regulator A (LmiA), which, in turn, activates locus of enterocyte effacement (LEE) genes to promote EHEC O157:H7 adherence in the low-magnesium conditions of the large intestine. This regulatory pathway is widely present in a range of EHEC and enteropathogenic E. coli (EPEC) serotypes. Disruption of this pathway significantly decreased EHEC O157:H7 adherence in the mouse intestinal tract. Moreover, mice fed a magnesium-rich diet showed significantly reduced EHEC O157:H7 adherence in vivo, indicating that magnesium may help in preventing EHEC and EPEC infection in humans.

Diamond anvil cell techniques have been improved to allow access to the multimegabar ultrahigh-pressure region for exploring novel phenomena in condensed matter. However, the only way to determine crystal structures of materials above 100 GPa, namely, X-ray diffraction (XRD), especially for low Z materials, remains nontrivial in the ultrahigh-pressure region, even with the availability of brilliant synchrotron X-ray sources. In this work, we perform a systematic study, choosing hydrogen (the lowest X-ray scatterer) as the subject, to understand how to better perform XRD measurements of low Z materials at multimegabar pressures. The techniques that we have developed have been proved to be effective in measuring the crystal structure of solid hydrogen up to 254 GPa at room temperature [C. Ji et al., Nature 573, 558–562 (2019)]. We present our discoveries and experiences with regard to several aspects of this work, namely, diamond anvil selection, sample configuration for ultrahigh-pressure XRD studies, XRD diagnostics for low Z materials, and related issues in data interpretation and pressure calibration. We believe that these methods can be readily extended to other low Z materials and can pave the way for studying the crystal structure of hydrogen at higher pressures, eventually testing structural models of metallic hydrogen.

Citrobacter species are opportunistic bacterial pathogens that have been implicated in both nosocomial and community-acquired infections. Among the genus Citrobacter, Citrobacter koseri is often isolated from clinical material, and has been known to cause meningitis and brain abscess in neonates and immunocompromised individuals. The virulence determinants of Citrobacter, however, remain largely unknown. Based on traditional methods, the genus Citrobacter has been divided into 11 species, but this has been problematic. Here, we determined an improved, detailed, and more accurate phylogeny of the genus Citrobacter based on whole genome sequence (WGS) data from 129 Citrobacter genomes, 31 of which were sequenced in this study. A maximum likelihood (ML) phylogeny constructed with core genome single-nucleotide polymorphisms (SNPs) classified all Citrobacter isolates into 11 distinct groups, with all C. koseri strains clustering into a single group. For comprehensive and systematic comparative genomic analyses, we investigated the distribution of virulence factors, resistance genes, and macromolecular secretion systems among the Citrobacter genus. Moreover, combined with group-specific genes analysis, we identified a key gene cluster for iron transport, which is present in the C. koseri group, but absent in other the groups, suggesting that the high-pathogenicity island (HPI) cluster may be important for the pathogenicity of C. koseri. Animal experiments showed that loss of the HPI cluster significantly decreased C. koseri virulence in mice and rat. Further, we provide evidence to explain why Citrobacter freundii is less susceptible than C. koseri to several antibiotics in silico. Overall, our data reveal novel virulence clusters specific to the predominantly pathogenic C. koseri strains, which form the basis for elucidating the virulence mechanisms underlying these important pathogens.

In the title complex, [MnIIMnIII2(C11H13NO4)2(CH3CO2)4(H2O)2]·2CH3CN·2H2O, there are two MnIII and one MnII atoms. The MnII atom lies on an inversion center and the MnIII—MnII—MnIII angle is therefore 180°, as required by crystallographic symmetry. The MnIII and MnII atoms are six-coordinated in a distorted octahedral geometry. In the crystal, complex molecules and solvent molecules are linked into a three-dimensional network by O—H...O and O—H...N hydrogen-bonding interactions.

Copyright of INMATEH - Agricultural Engineering is the property of INMATEH - Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)