Novel insights into dimethylsulfoniopropionate cleavage by deep subseafloor fungi.

Dimethylsulfoniopropionate (DMSP), a key organic sulfur compound in marine and subseafloor sediments, is degraded by phytoplankton and bacteria, resulting in the release of the climate-active volatile gas dimethylsulfide (DMS). However, it remains unclear if dominant eukaryotic fungi in subseafloor sediments possess specific abilities and metabolic mechanisms for DMSP degradation and DMS formation. Our study provides the first evidence that fungi from coal-bearing sediments ∼2 km below the seafloor, such as Aspergillus spp., Chaetomium globosum, Cladosporium sphaerospermum, and Penicillium funiculosum, can degrade DMSP and produce DMS. In Aspergillus sydowii 29R-4-F02, which exhibited the highest DMSP-dependent DMS production rate (16.95 pmol/µg protein/min), two DMSP lyase genes, dddP and dddW, were identified. Remarkably, the dddW gene, previously observed only in bacteria, was found to be crucial for fungal DMSP cleavage. These findings not only extend the list of fungi capable of degrading DMSP, but also enhance our understanding of DMSP lyase diversity and the role of fungi in DMSP decomposition in subseafloor sedimentary ecosystems.

Enhancing the expression of the unspecific peroxygenase in Komagataella phaffii through a combination strategy.

The unspecific peroxygenase (UPO) from Cyclocybe aegerita (AaeUPO) can selectively oxidize C-H bonds using hydrogen peroxide as an oxygen donor without cofactors, which has drawn significant industrial attention. Many studies have made efforts to enhance the overall activity of AaeUPO expressed in Komagataella phaffii by employing strategies such as enzyme-directed evolution, utilizing appropriate promoters, and screening secretion peptides. Building upon these previous studies, the objective of this study was to further enhance the expression of a mutant of AaeUPO with improved activity (PaDa-I) by increasing the gene copy number, co-expressing chaperones, and optimizing culture conditions. Our results demonstrated that a strain carrying approximately three copies of expression cassettes and co-expressing the protein disulfide isomerase showed an approximately 10.7-fold increase in volumetric enzyme activity, using the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as the substrate. After optimizing the culture conditions, the volumetric enzyme activity of this strain further increased by approximately 48.7%, reaching 117.3 U/mL. Additionally, the purified catalytic domain of PaDa-I displayed regioselective hydroxylation of R-2-phenoxypropionic acid. The results of this study may facilitate the industrial application of UPOs. KEY POINTS: • The secretion of the catalytic domain of PaDa-I can be significantly enhanced through increasing gene copy numbers and co-expressing of protein disulfide isomerase. • After optimizing the culture conditions, the volumetric enzyme activity can reach 117.3 U/mL, using the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as the substrate. • The R-2-phenoxypropionic acid can undergo the specific hydroxylation reaction catalyzed by catalytic domain of PaDa-I, resulting in the formation of R-2-(4-hydroxyphenoxy)propionic acid.

Ginkgo biloba and Its Chemical Components in the Management of Alzheimer's Disease.

The pathogenesis of Alzheimer's disease (AD), a degenerative disease of the central nervous system, remains unclear. The main manifestations of AD include cognitive and behavioral disorders, neuropsychiatric symptoms, neuroinflammation, amyloid plaques, and neurofibrillary tangles. However, current drugs for AD once the dementia stage has been reached only treat symptoms and do not delay progression, and the research and development of targeted drugs for AD have reached a bottleneck. Thus, other treatment options are needed. Bioactive ingredients derived from plants are promising therapeutic agents. Specifically, Ginkgo biloba (Gb) extracts exert anti-oxidant, anticancer, neuroplastic, neurotransmitter-modulating, blood fluidity, and anti-inflammatory effects, offering alternative options in the treatment of cardiovascular, metabolic, and neurodegenerative diseases. The main chemical components of Gb include flavonoids, terpene lactones, proanthocyanidins, organic acids, polysaccharides, and amino acids. Gb and its extracts have shown remarkable therapeutic effects on various neurodegenerative diseases, including AD, with few adverse reactions. Thus, high-quality Gb extracts are a well-established treatment option for AD. In this review, we summarize the insights derived from traditional Chinese medicine, experimental models, and emerging clinical trials on the role of Gb and its chemical components in the treatment of the main clinical manifestations of AD.

Outdoor gardening activity with different frequency and duration may be associated with reduction of total and cause-specific mortality risk for general U.S. adults: Findings from the NHANES.

BACKGROUND AND AIMS: Engaging in recommended levels of physical activity (PA) is associated with reduced overall and cause-specific mortality rates. Our study aims to examine the relationship between gardening-specific PA and all-cause and cause-specific mortality based on representative U.S. adults. METHODS AND RESULTS: A total of 13,812 adults representing 663.5 million non-institutionalized U.S. adults were included in the National Health and Nutrition Examination Survey. Self-reported gardening activity (GA) was assessed by a validated questionnaire, and outcomes of interest were all-cause mortality and mortality specific to certain causes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using survey-multivariable Cox proportional hazards models. During a median follow-up period of 16.8 years (Interquartile range = 14.8-18.7), there were 3,476 deaths. After adjusting for potential covariates, we found that participants exposed to GA were more likely to have a lower risk of total mortality [HR (95% CI): 0.76 (0.68, 0.85), P-value < 0.001], cancer-specific mortality [HR (95% CI): 0.81 (0.67, 0.99), P-value < 0.05], cardiovascular disease mortality [HR (95% CI): 0.65 (0.53, 0.80), P-value < 0.001], and respiratory disease mortality [HR (95% CI): 0.66 (0.45, 0.98), P-value < 0.05], compared to those without GA exposure. Furthermore, engaging in GA more frequently and for longer durations was significantly associated with a lower total mortality risk. CONCLUSION: Our study provides evidence that engaging in GA is associated with a decreased risk of overall and cause-specific mortality. However, further longitudinal or interventional studies are needed to investigate the potential benefits of GA.

Maximizing the potential of nitrilase: Unveiling their diversity, catalytic proficiency, and versatile applications.

Nitrilases represent a distinct class of enzymes that play a pivotal role in catalyzing the hydrolysis of nitrile compounds, leading to the formation of corresponding carboxylic acids. These enzymatic entities have garnered significant attention across a spectrum of industries, encompassing pharmaceuticals, agrochemicals, and fine chemicals. Moreover, their significance has been accentuated by mounting environmental pressures, propelling them into the forefront of biodegradation and bioremediation endeavors. Nevertheless, the natural nitrilases exhibit intrinsic limitations such as low thermal stability, narrow substrate selectivity, and inadaptability to varying environmental conditions. In the past decade, substantial efforts have been made in elucidating the structural underpinnings and catalytic mechanisms of nitrilase, providing basis for engineering of nitrilases. Significant breakthroughs have been made in the regulation of nitrilases with ideal catalytic properties and application of the enzymes for industrial productions. This review endeavors to provide a comprehensive discourse and summary of recent research advancements related to nitrilases, with a particular emphasis on the elucidation of the structural attributes, catalytic mechanisms, catalytic characteristics, and strategies for improving catalytic performance of nitrilases. Moreover, the exploration extends to the domain of process engineering and the multifarious applications of nitrilases. Furthermore, the future development trend of nitrilases is prospected, providing important guidance for research and application in the related fields.

Plantaginis semen ameliorates diabetic kidney disease via targeting the sphingosine kinase 1/sphingosine-1-phosphate pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Plantaginis Semen (PS) is widely utilized as a common herb in several Asian countries, particularly China, due to its diuretic, anti-hypertensive, anti-hyperlipidemic, and anti-hyperglycemic properties. Furthermore, it is acknowledged for its ability to mitigate renal complications associated with metabolic syndrome. Despite its extensive usage, there is limited systematic literature elucidating its therapeutic mechanisms, thus emphasizing the necessity for comprehensive investigations in this field. AIM: This study aims to comprehensively evaluate the therapeutical potential of PS in treating diabetic kidney disease (DKD) and to elucidate the underlying mechanisms through in vivo and in vitro models. METHODS: The main composition of PS were characterized using the UPLC-QTOF-MS method. For the in vivo investigation, a mouse model mediated by streptozocin (STZ) associated with a high-fat diet (HFD) and unilateral renal excision was established. The mice were split into 6 groups (n = 8): control group (CON group), DKD group, low-dose of Plantago asiatica L. seed extract group (PASE-L group, 3 g/kg/d), medium-dose of PASE group (PASE-M, 6 g/kg/d), high-dose of PASE group (PASE-H, 9 g/kg/d), and positive drug group (valsartan, VAS group, 12 mg/kg/d). After 8 weeks of treatment, the damage induced by DKD was evaluated by using relevant parameters of urine and blood. Furthermore, indicators of inflammation and factors associated with the SphK1-S1P signaling pathway were investigated. For the in vitro study, the cell line HBZY-1 was stimulated by high glucose (HG), they were then co-cultured with different concentrations of PASE, and the corresponding associated inflammatory and sphingosine kinase 1/sphingosine-1-phosphate (SphK1-S1P) factors were examined. RESULTS: A total of 59 major components in PS were identified, including flavonoids, iridoids, phenylethanol glycosides, guanidine derivatives, and fatty acids. In the mouse model, PS was found to significantly improve body weight, decrease fasting blood glucose (FBG) levels, increased glucose tolerance and insulin tolerance, improved kidney-related markers compared to the DKD group, pathological changes in the kidneys also improved dramatically. These effects showed a dose-dependent relationship, with higher PASE concentrations yielding significantly better outcomes than lower concentrations. However, the effects of the low PASE concentration were not evident for some indicators. In the cellular model, the high dose of PASE suppressed high glucose (HG) stimulated renal mesangial cell proliferation, suppressed inflammatory factors and NF-κB, and decreased the levels of fibrillin-1(FN-1) and collagen IV(ColIV). CONCLUSION: Our results indicate that PS exerts favorable therapeutic effects on DKD, with the possible mechanisms including the inhibition of inflammatory pathways, suppression of mRNA levels and protein expressions of SphK1 and S1P, consequently leading to reduced overexpression of FN-1 and ColIV, thereby warranting further exploration.

Cumulative inequality in social determinants of health in relation to depression symptom: An analysis of nationwide cross-sectional data from U.S. NHANES 2005-2018.

Social determinants of health (SDoH) have been linked to a higher likelihood of experiencing mental health problems. This study aimed to investigate whether the accumulation of unfavorable SDoH is associated with depression symptom. Data was gathered from a representative population participating in the U.S. National Health and Nutrition Examination Survey spanning from 2005 to 2018. Self-reported SDoH were operationalized according to the criteria outlined in Healthy People 2030, with a cumulative measure of unfavorable SDoH calculated for analysis. The presence of depression symptom was identified using the Patient Health Questionnaire in a representative sample of 30,762 participants (49.2 % males) representing 1,392 million non-institutionalized U.S. adults, with 2,675 (8.7 %) participants showing depression symptom. Unfavorable SDoH were found to be significantly and independently associated with depression symptom. Individuals facing multiple unfavorable SDoHs were more likely to experience depression symptom (P for trend < 0.001). For instance, a positive association was observed in participants exposed to six or more unfavorable SDoHs with depression symptom (AOR = 3.537, 95 % CI: 1.781, 7.075, P-value < 0.001). The findings emphasize that the likelihood of developing depression symptom significantly increases when multiple SDoHs are present, compared to just a single SDoH.

Not exclusively the activity, but the sweet spot: a dehydrogenase point mutation synergistically boosts activity, substrate tolerance, thermal stability and yield.

Catalytic activity is undoubtedly a key focus in enzyme engineering. The complicated reaction conditions hinder some enzymes from industrialization even though they have relatively promising activity. This has occurred to some dehydrogenases. Hydroxysteroid dehydrogenases (HSDHs) specifically catalyze the conversion between hydroxyl and keto groups, and hold immense potential in the synthesis of steroid medicines. We underscored the importance of 7α-HSDH activity, and analyzed the overall robustness and underlying mechanisms. Employing a high-throughput screening approach, we comprehensively assessed a mutation library, and obtained a mutant with enhanced enzymatic activity and overall stability/tolerance. The superior mutant (I201M) was identified to harbor improved thermal stability, substrate susceptibility, cofactor affinity, as well as the yield. This mutant displayed a 1.88-fold increase in enzymatic activity, a 1.37-fold improvement in substrate tolerance, and a 1.45-fold increase in thermal stability when compared with the wild type (WT) enzyme. The I201M mutant showed a 2.25-fold increase in the kcat/KM ratio (indicative of a stronger binding affinity for the cofactor). This mutant did not exhibit the highest enzyme activity compared with all the tested mutants, but these improved characteristics contributed synergistically to the highest yield. When a substrate at 100 mM was present, the 24 h yield by I201M reached 89.7%, significantly higher than the 61.2% yield elicited by the WT enzyme. This is the first report revealing enhancement of the catalytic efficiency, cofactor affinity, substrate tolerance, and thermal stability of NAD(H)-dependent 7α-HSDH through a single-point mutation. The mutated enzyme reached the highest enzymatic activity of 7α-HSDH ever reported. High enzymatic activity is undoubtedly crucial for enabling the industrialization of an enzyme. Our findings demonstrated that, when compared with other mutants boasting even higher enzymatic activity, mutants with excellent overall robustness were superior for industrial applications. This principle was exemplified by highly active enzymes such as 7α-HSDH.

Improvement of an enzymatic cascade synthesis of nicotinamide mononucleotide via protein engineering and reaction-process reinforcement.

Enzymatic synthesis of ß-nicotinamide mononucleotide (NMN) from D-ribose has garnered widespread attention due to its cheap material, the use of mild reaction conditions, and the ability to produce highly pure products with the desired optical properties. However, the overall NMN yield of this method is impeded by the low activity of rate-limiting enzymes. The ribose-phosphate diphosphokinase (PRS) and nicotinamide phosphoribosyltransferase (NAMPT), that control the rate of the reaction, were engineered to improve the reaction efficacy. The actives of mutants PRS-H150Q and NAMPT-Y15S were 334% and 57% higher than that of their corresponding wild-type enzymes, respectively. Furthermore, by adding pyrophosphatase, the byproduct pyrophosphate which can inhibit the activity of NAMPT was degraded, leading to a 6.72% increase in NMN yield. Following with reaction-process reinforcement, a high yield of 8.10 g L-1 NMN was obtained after 3 h of reaction, which was 56.86-fold higher than that of the stepwise reaction synthesis (0.14 g L-1 ), indicating that the in vitro enzymatic synthesis of NMN from D-ribose and niacinamide is an economical and feasible route.

An angel or a devil? Current view on the role of CD8+ T cells in the pathogenesis of myasthenia gravis.

BACKGROUND: Myasthenia gravis (MG) and the experimental autoimmune MG (EAMG) animal model are characterized by T-cell-induced and B-cell-dominated autoimmune diseases that affect the neuromuscular junction. Several subtypes of CD4+ T cells, including T helper (Th) 17 cells, follicular Th cells, and regulatory T cells (Tregs), contribute to the pathogenesis of MG. However, increasing evidence suggests that CD8+ T cells also play a critical role in the pathogenesis and treatment of MG. MAIN BODY: Herein, we review the literature on CD8+ T cells in MG, focusing on their potential effector and regulatory roles, as well as on relevant evidence (peripheral, in situ, cerebrospinal fluid, and under different treatments), T-cell receptor usage, cytokine and chemokine expression, cell marker expression, and Treg, Tc17, CD3+CD8+CD20+ T, and CXCR5+ CD8+ T cells. CONCLUSIONS: Further studies on CD8+ T cells in MG are necessary to determine, among others, the real pattern of the Vß gene usage of autoantigen-specific CD8+ cells in patients with MG, real images of the physiology and function of autoantigen-specific CD8+ cells from MG/EAMG, and the subset of autoantigen-specific CD8+ cells (Tc1, Tc17, and IL-17+IFN-γ+CD8+ T cells). There are many reports of CD20-expressing T (or CD20 + T) and CXCR5+ CD8 T cells on autoimmune diseases, especially on multiple sclerosis and rheumatoid arthritis. Unfortunately, up to now, there has been no report on these T cells on MG, which might be a good direction for future studies.

Sustainable management and valorization of biomass wastes using synthetic microbial consortia.

In response to the persistent expansion of global resource demands, considerable attention has been directed toward the synthetic microbial consortia (SMC) within the domain of microbial engineering, aiming to address the sustainable management and valorization of biomass wastes. This comprehensive review systematically encapsulates the most recent advancements in research and technological applications concerning the utilization of SMC for biomass waste treatment. The construction strategies of SMC are briefly outlined, and the diverse applications of SMC in biomass wastes treatment are explored, with particular emphasis on its potential advantages in waste degradation, hazardous substances control, and high value-added products conversion. Finally, recommendations for the future development of SMC technology are proposed, and prospects for its sustainable application are discussed.

Biosynthesis of Nicotinamide Mononucleotide: Synthesis Method, Enzyme, and Biocatalytic System.

Nicotinamide mononucleotide (NMN) has garnered substantial interest as a functional food product. Industrial NMN production relies on chemical methods, facing challenges in separation, purification, and regulatory complexities, leading to elevated prices. In contrast, NMN biosynthesis through fermentation or enzyme catalysis offers notable benefits like eco-friendliness, recyclability, and efficiency, positioning it as a primary avenue for future NMN synthesis. Enzymatic NMN synthesis encompasses the nicotinamide-initial route and nicotinamide ribose-initial routes. Key among these is nicotinamide riboside kinase (NRK), pivotal in the latter route. The NRK-mediated biosynthesis is emerging as a prominent trend due to its streamlined route, simplicity, and precise specificity. The essential aspect is to obtain an engineered NRK that exhibits elevated activity and robust stability. This review comprehensively assesses diverse NMN synthesis methods, offering valuable insights into efficient, sustainable, and economical production routes. It spotlights the emerging NRK-mediated biosynthesis pathway and its significance. The establishment of an adenosine triphosphate (ATP) regeneration system plays a pivotal role in enhancing NMN synthesis efficiency through NRK-catalyzed routes. The review aims to be a reference for researchers developing green and sustainable NMN synthesis, as well as those optimizing NMN production.

Identification of a novel growth-associated promoter for biphasic expression of heterogenous proteins in Pichia pastoris.

Pichia pastoris (P. pastoris) is one of the most popular cell factories for expressing exogenous proteins and producing useful chemicals. The alcohol oxidase 1 promoter (PAOX1) is the most commonly used strong promoter in P. pastoris and has the characteristic of biphasic expression. However, the inducer for PAOX1, methanol, has toxicity and poses risks in industrial settings. In the present study, analyzing transcriptomic data of cells collected at different stages of growth found that the formate dehydrogenase (FDH) gene ranked 4960th in relative expression among 5032 genes during the early logarithmic growth phase but rose to the 10th and 1st during the middle and late logarithmic growth phases, respectively, displaying a strict biphasic expression characteristic. The unique transcriptional regulatory profile of the FDH gene prompted us to investigate the properties of its promoter (PFDH800). Under single-copy conditions, when a green fluorescent protein variant was used as the expression target, the PFDH800 achieved 119% and 69% of the activity of the glyceraldehyde-3-phosphate dehydrogenase promoter and PAOX1, respectively. After increasing the copy number of the expression cassette in the strain to approximately four copies, the expression level of GFPuv driven by PFDH800 increased to approximately 2.5 times that of the strain containing GFPuv driven by a single copy of PAOX1. Our PFDH800-based expression system exhibited precise biphasic expression, ease of construction, minimal impact on normal cellular metabolism, and high strength. Therefore, it has the potential to serve as a new expression system to replace the PAOX1 promoter.IMPORTANCEThe alcohol oxidase 1 promoter (PAOX1) expression system has the characteristics of biphasic expression and high expression levels, making it the most widely used promoter in the yeast Pichia pastoris. However, PAOX1 requires methanol induction, which can be toxic and poses a fire hazard in large quantities. Our research has found that the activity of PFDH800 is closely related to the growth state of cells and can achieve biphasic expression without the need for an inducer. Compared to other reported non-methanol-induced biphasic expression systems, the system based on the PFDH800 offers several advantages, including high expression levels, simple construction, minimal impact on cellular metabolism, no need for an inducer, and the ability to fine-tune expression.

Contribution of individual and cumulative social determinants of health underlying gender disparities in periodontitis in a representative US population: A cross-sectional NHANES study.

AIM: To examine the impact of both individual and cumulative social determinants of health (SDoH) on the likelihood of developing periodontitis, while also exploring any gender disparities in this relationship. MATERIALS AND METHODS: Data of self-reported SDoH domains and sub-items based on Healthy People 2030 were obtained from the U.S. National Health and Nutrition Examination Surveys between 1999 and 2014. Logistic regression models, weighted by survey responses, were used to examine the relationship between SDoH (including eight sub-items and the cumulative number of unfavourable SDoH) and periodontitis. The results were further analysed by gender. RESULTS: A total of 18,075 participants (8867 males and 9208 females) were included in the main analysis, of which 5814 (32.2%) had periodontitis. The study found that certain unfavourable SDoH were individually associated with higher odds of periodontitis, and the cumulative number of unfavourable SDoH was positively linked to the odds of developing periodontitis. Furthermore, males exposed to more unfavourable SDoH appeared to be more susceptible to developing periodontitis than females. CONCLUSIONS: The findings suggest that unfavourable SDoH, especially when they accumulate, are associated with an increased odds of periodontitis and contribute to gender disparities within the U.S.

Lewis-acid-catalyzed phosphorylation of alcohols.

An efficient method has been developed for reacting dialkyl H-phosphonates or diarylphosphine oxides with alcohols for constructing C-P bonds. This reaction was catalyzed by Lewis acid and involved nucleophilic substitution. A series of diphenylphosphonates and diphenylphosphine oxides were obtained, from the phosphorylation of alcohols, with good-to-excellent yields.

Identification of a novel thermostable transaminase and its application in L-phosphinothricin biosynthesis.

Transaminase (TA) is a crucial biocatalyst for enantioselective production of the herbicide L-phosphinothricin (L-PPT). The use of enzymatic cascades has been shown to effectively overcome the unfavorable thermodynamic equilibrium of TA-catalyzed transamination reaction, also increasing demand for TA stability. In this work, a novel thermostable transaminase (PtTA) from Pseudomonas thermotolerans was mined and characterized. The PtTA showed a high specific activity (28.63 U/mg) towards 2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid (PPO), with excellent thermostability and substrate tolerance. Two cascade systems driven by PtTA were developed for L-PPT biosynthesis, including asymmetric synthesis of L-PPT from PPO and deracemization of D, L-PPT. For the asymmetric synthesis of L-PPT from PPO, a three-enzyme cascade was constructed as a recombinant Escherichia coli (E. coli G), by co-expressing PtTA, glutamate dehydrogenase (GluDH) and D-glucose dehydrogenase (GDH). Complete conversion of 400 mM PPO was achieved using only 40 mM amino donor L-glutamate. Furthermore, by coupling D-amino acid aminotransferase (Ym DAAT) from Bacillus sp. YM-1 and PtTA, a two-transaminase cascade was developed for the one-pot deracemization of D, L-PPT. Under the highest reported substrate concentration (800 mM D, L-PPT), a 90.43% L-PPT yield was realized. The superior catalytic performance of the PtTA-driven cascade demonstrated that the thermodynamic limitation was overcome, highlighting its application prospect for L-PPT biosynthesis. KEY POINTS: • A novel thermostable transaminase was mined for L-phosphinothricin biosynthesis. • The asymmetric synthesis of L-phosphinothricin was achieved via a three-enzyme cascade. • Development of a two-transaminase cascade for D, L-phosphinothricin deracemization.

Microstructure characterization of different types of chlamydospores in Arthrobotrys flagrans.

The morphological and structural differences of different types of chlamydospore of Arthrobotrys flagrans, a nematophagous fungus, were studied under light microscope and electron microscope to provide a reference for the biological control of parasitic nematodiasis. In this study, A. flagrans isolate F088 dormant chlamydospore and nondormant chlamydospore were selected as the research objects. The structural differences of these spores were observed by optical microscopy through lactol cotton blue, Trypan blue, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) staining. FunXite -1, 4',6-diamidino-2-phenylindole, and calcofluor white staining were used to observe the metabolic activity, cell wall, and nucleus differences of the two types of spores under fluorescence microscope. Ultrastructure of the two kinds of spores was observed using scanning electron microscope (SEM) and transmission electron microscope (TEM). Since lacto phenol cotton blue, trypan blue staining cannot distinguish dormant spores from dead spores, MTT assay was performed. Fluorescence microscopy observation showed that the cytoplasmic metabolic activity of nondormant spores was stronger than that of dormant spores. The nucleus of dormant spores was bright blue, and their fluorescence was stronger than that of nondormant spores. The cell wall of nondormant spores produced stronger yellow-green fluorescence than that of dormant spores. Ultrastructural observation showed that there were globular protuberances on the surface of the two types of spores but with no significant difference between them. The inner wall of dormant spore possesses a thick zona pellucida with high electron density which was significantly thicker than that of nondormant spores, and their cytoplasm is also changed. In this study, the microstructure characteristics of dormant and nondormant chlamydospores of A. flagrans fungi were preliminarily clarified, suggesting that the state of cell wall and intracellular materials were changed after spores entered to dormancy.

Breeding of Saccharomyces cerevisiae with a High-Throughput Screening Strategy for Improvement of S-Adenosyl-L-Methionine Production.

S-adenosyl-l-methionine (SAM), a vital physiologically active substance in living organisms, is produced by fermentation over Saccharomyces cerevisiae. The main limitation in SAM production was the low biosynthesis ability of SAM in S. cerevisiae. The aim of this work is to breed an SAM-overproducing mutant through UV mutagenesis coupled with high-throughput selection. Firstly, a high-throughput screening method by rapid identification of positive colonies was conducted. White colonies on YND medium were selected as positive strains. Then, nystatin/sinefungin was chosen as a resistant agent in directed mutagenesis. After several cycles of mutagenesis, a stable mutant 616-19-5 was successfully obtained and exhibited higher SAM production (0.41 g/L vs 1.39 g/L). Furthermore, the transcript levels of the genes SAM2, ADO1, and CHO2 involved in SAM biosynthesis increased, while ergosterol biosynthesis genes in mutant 616-19-5 significantly decreased. Finally, building on the above work, S. cerevisiae 616-19-5 could produce 10.92 ± 0.2 g/L SAM in a 5-L fermenter after 96 h of fermentation, showing a 2.02-fold increase in the product yield compared with the parent strain. Paving the way of breeding SAM-overproducing strain has improved the good basis for SAM industrial production.

Sexual orientation disparities in the prevalence of suicidal ideation among U.S adults aged 20 to 59 years: Results from NHANES 2005-2016.

Existing studies have been limited in providing nationally representative data on the relationship between sexual orientation and suicidal ideation (SI) among adults in the U.S. particularly in terms of gender and racial differences. To fill this research gap, we conducted a study using data from the NHANES conducted between 2005 and 2016. Survey-weighted logistic regression models were used to investigate the relationship between sexual orientation and SI risk. Additionally, we performed further analysis by stratifying the data based on demographic variables and performed sensitivity analysis to ensure the reliability of our findings. This study included a weighted sample of 16,564 adults, representing a noninstitutionalized U.S population of 840.1 million. The overall age-adjusted prevalence of SI was found to be 3.5 %. After adjusting for relevant covariates, the study revealed that individuals who identified as something else, homosexual, and bisexual had a higher prevalence risk of suicidal ideation (SI) compared to heterosexual participants. Additionally, the study found that heterosexual participants were 74.4 % less likely to experience SI compared to bisexual individuals. These findings highlight the urgent requirement for inclusive and supportive prevention strategies to effectively address SI among adult sexual minorities in the U.S.

Cardiac-specific deletion of BRG1 ameliorates ventricular arrhythmia in mice with myocardial infarction.

Malignant ventricular arrhythmia (VA) after myocardial infarction (MI) is mainly caused by myocardial electrophysiological remodeling. Brahma-related gene 1 (BRG1) is an ATPase catalytic subunit that belongs to a family of chromatin remodeling complexes called Switch/Sucrose Non-Fermentable Chromatin (SWI/SNF). BRG1 has been reported as a molecular chaperone, interacting with various transcription factors or proteins to regulate transcription in cardiac diseases. In this study, we investigated the potential role of BRG1 in ion channel remodeling and VA after ischemic infarction. Myocardial infarction (MI) mice were established by ligating the left anterior descending (LAD) coronary artery, and electrocardiogram (ECG) was monitored. Epicardial conduction of MI mouse heart was characterized in Langendorff-perfused hearts using epicardial optical voltage mapping. Patch-clamping analysis was conducted in single ventricular cardiomyocytes isolated from the mice. We showed that BRG1 expression in the border zone was progressively increased in the first week following MI. Cardiac-specific deletion of BRG1 by tail vein injection of AAV9-BRG1-shRNA significantly ameliorated susceptibility to electrical-induced VA and shortened QTc intervals in MI mice. BRG1 knockdown significantly enhanced conduction velocity (CV) and reversed the prolonged action potential duration in MI mouse heart. Moreover, BRG1 knockdown improved the decreased densities of Na+ current (INa) and transient outward potassium current (Ito), as well as the expression of Nav1.5 and Kv4.3 in the border zone of MI mouse hearts and in hypoxia-treated neonatal mouse ventricular cardiomyocytes. We revealed that MI increased the binding among BRG1, T-cell factor 4 (TCF4) and ß-catenin, forming a transcription complex, which suppressed the transcription activity of SCN5A and KCND3, thereby influencing the incidence of VA post-MI.