Observations on the ultrastructure of the oral appendages of Glenea cantor Fabricius (Coleoptera: Lamiinae).

Using scanning electron microscopy, we examined the gross and ultrastructure morphology of the mandibles, labial palpi, and mandibular palpi of adult male and female Glenea cantor beetles. The morphology of these parts, both in their gross and ultrastructure, varied significantly between males and females. The lengths of the mandible, labial palpi, and mandibular palpi were clearly noticeably longer in females than in men, which is mostly related to the oviposition mechanism. In terms of the ultrastructural morphology of the mandibles, labial palpi, and mandibular palpi, seven types of sensilla were found on these parts: sensilla twig basiconica (STB I, II, III, and IV), sensilla chaetica (Scheme IV and V), Böhm's bristles (Bb), sensilla placodea (SP), sensilla trichodea (ST II), sensilla plate (SP), sensilla coeloconica (SC), and sensilla campaniformia (SCa). Females have significantly more ST I and Scheme III on their mandibles than males. The mechanical sensors SCh and Bb, olfactory sensor ST II, taste sensor STB IV, and carbon dioxide sensor and temperature and humidity sensors SC, SP, and SCa were much more developed on the labial and maxillary palpi of females compared to those of males, which further clarified the significance of the oral appendages in oviposition behavior. These findings will advance information-based technique design and the creation of information-based pest control strategies by assisting in our understanding of the host preference and oviposition behavior of adult G. cantor. RESEARCH HIGHLIGHTS: The external morphology and distribution of the oral appendages of Glenea cantor between sexes has been researched through scanning electron microscopy (SEM) for the first time. Several significant differences between males and females have been found by analyzing the oral appendages of G. cantor with SEM. The differences in the structure of oral appendages of G. cantor between sexes reflect functional differences in reproductive behaviors.

MAL31, a sugar transporter involved in pullulan biosynthesis in Aureobasidium pullulans.

To investigate the role of the sugar transporter MAL31 on pullulan biosynthesis, the coding gene mal31 was respectively disrupted and overexpressed in the parental strain A. pullulans CCTCC M 2012259 to construct mutants of A. pullulans Δmal31 and A. pullulans Mal31. Batch pullulan production significantly decreased by 69.1 % in A. pullulans Δmal31 but increased by 15.9 % in A. pullulans Mal31, as compared to the parental strain. We performed kinetics analysis, assays of key enzymes, determination of intracellular UDPG, NADH, and ATP contents, and measurement of transcriptional levels of genes associated with pullulan biosynthesis and excretion. The results confirmed that the mal31 disruption decreased the glucose consumption rate, decreased the formation rate and titer of pullulan, but increased the intracellular UDPG supply for ß-glucan accumulation. In contrast, the mal31 overexpression increased the transcriptional levels of genes associated with pullulan biosynthesis, and accelerated the rates of glucose consumption and pullulan formation, thereby increased pullulan production. Our findings revealed that MAL31 is involved in the transport of precursors for pullulan biosynthesis. This study provides an accurate operating site for genetic modification of A. pullulans for improving pullulan production and also presents a feasible technique route for the overproduction of other polysaccharides.

The efficacy and safety of acupuncture in nonalcoholic fatty liver disease: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The aim of this study was to determine the efficacy and safety of acupuncture treatment (AT) or acupuncture plus conventional medicine (CM) versus CM alone using a meta-analysis of all published randomized controlled trials (RCTs) for nonalcoholic fatty liver disease (NAFLD). METHODS: Eight databases were searched independently from inception to April 30, 2020. RCTs were included if they contained reports on the use acupuncture or the use of acupuncture combined with CM and compared with the use of CM. Summary odds ratio (OR) and 95% confidence intervals (CIs) were used to calculate the overall clinical efficacy. Secondary outcomes, namely aspartate aminotransferase, alanine aminotransferase, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and body mass index, were calculated by mean difference with 95% CIs. RESULTS: After the final screening, 8 RCTs with 939 patients were included. This meta-analysis showed that AT was superior to CM in improving overall clinical efficacy (OR = 3.19, 95% CI: 2.06-4.92, P  < .00001). In addition, AT plus CM could significantly improve overall clinical efficacy compared to treatment with CM alone (OR = 5.11, 95% CI: 2.43-10.75, P  < .0001). Moreover, the benefits were also demonstrated in other outcomes, including alanine aminotransferase, aspartate aminotransferase, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol indexes. However, AT plus CM could not decrease body mass index levels in comparison with CM. The safety profile of Acupuncture therapy was satisfactory. Taichong, Zusanli, Fenglong, and Sanyinjiao were major acupoints on NAFLD treatment. CONCLUSION: Acupuncture may be effective and safe for treatment of NAFLD. However, due to insufficient methodological quality and sample size, further high-quality studies are needed.

Improved production of ß-glucan by a T-DNA-based mutant of Aureobasidium pullulans.

To improve ß-1,3-1,6-D-glucan (ß-glucan) production by Aureobasidium pullulans, an Agrobacterium tumefaciens-mediated transformation method was developed to screen a mutant A. pullulans CGMCC 19650. Based on thermal asymmetric-interlaced PCR detection, DNA sequencing, BLAST analysis, and quantitative real-time PCR assay, the T-DNA was identified to be inserted in the coding region of mal31 gene, which encodes a sugar transporter involved in pullulan biosynthesis in the mutant. The maximal biomass and ß-glucan production under batch fermentation were significantly increased by 47.6% and 78.6%, respectively, while pullulan production was decreased by 41.7% in the mutant, as compared to the parental strain A. pullulans CCTCC M 2012259. Analysis of the physiological mechanism of these changes revealed that mal31 gene disruption increased the transcriptional levels of pgm2, ugp, fks1, and kre6 genes; increased the amounts of key enzymes associated with UDPG and ß-glucan biosynthesis; and improved intracellular UDPG contents and energy supply, all of which favored ß-glucan production. However, the T-DNA insertion decreased the transcriptional levels of ags2 genes, and reduced the biosynthetic capability to form pullulan, resulting in the decrease in pullulan production. This study not only provides an effective approach for improved ß-glucan production by A. pullulans, but also presents an accurate and useful gene for metabolic engineering of the producer for efficient polysaccharide production. KEY POINTS: • A mutant A. pullulans CGMCC 19650 was screened by using the ATMT method. • The mal31 gene encoding a sugar transporter was disrupted in the mutant. • ß-Glucan produced by the mutant was significantly improved.

Variation of rooftop thermal environment with roof typology: a field experiment in Kitakyushu, Japan.

While urban open spaces have been shrinking with the rapid urbanization, rooftop space use is an alternative solution to such problems. Rooftop thermal environment is a critical consideration under global warming and local warming. Although there have been studies on rooftop thermal environment, variation of rooftop thermal environment with roof typology has not been fully revealed to support rooftop space design. To fill this gap, a field experiment was conducted over green roof (GR), wooden roof (WR), and shaded roof (SR) in a temperate city of Kitakyushu, Japan. Environmental parameters such as solar radiation, air temperature, and relative humidity at different heights of these three roofs were recorded, to understand rooftop thermal environment and daily heat stress variation with rooftop types and the height above roof surface. The results indicate that WR had the highest diurnal near-surface temperature and the worst heat stress, where the near-surface heat stress could even reach the danger level. GR exhibited the lowest diurnal near-surface temperature and heat stress, where the heat stress was only under caution and almost safe condition. SR exhibited the lowest diurnal 1-m temperature and SR had the weakest heat stress, indicating the significance of installing shading devices for rooftop thermal environment improvement and heat stress alleviation. GR exhibited excellent performance in reducing air temperature and heat stress at the pedestrian level, where its worst heat stress was only in caution condition. Compared with that at 1-m height, moreover, 1-cm temperature and heat stress of WR and SR were generally higher, indicating that people may undergo worse heat stress when kneeling or sitting compared with upright activities. Moreover, GR suppressed near-surface heat stress due to its excellent cooling performance.

Regulatory molecule cAMP changes cell fitness of the engineered Escherichia coli for terpenoids production.

Terpenoids are a class of natural compounds with many important functions and applications. They are synthesized from a long synthetic pathway of isoprenyl unit coupling with the myriads of terpene synthases. Owing to the catalytic divergence of terpenoids synthesis, microbial production of terpenoids is compromised to the complexity of pathway engineering and suffers from the metabolic engineering burden. In this work, the adaptive Escherichia coli HP variant exhibited a general cell fitness in terpenoid synthesis. Especially, it could yield taxadiene of 193.2 mg/L in a test tube culture, which is a five-fold increase over the production in the wild type E. coli DH5α. Mutational analyses indicated that IS10 insertion in adenylate cyclase CyaA (CyaAHP) resulted in lowering intracellular cyclic AMP (cAMP), which could regulate its receptor protein CRP to rewire cell metabolism and contributed to the improved cell fitness. Our results suggested a way to manipulate cell fitness for terpenoids production and other products.

Efficacy and safety of Shenkang injection as adjuvant therapy in patients with diabetic nephropathy: A protocol for systematic review and meta-analysis.

BACKGROUND: Diabetic nephropathy is a frequent microvascular complication of diabetes mellitus that causes end-stage renal disease most of the time. In China, Shenkang injection is one of widely used traditional Chinese medicine for treating chronic kidney disease, but its efficacy and safety have not yet been clarified. We will systematically review the current randomized controlled trial (RCT) evidence to summarize the efficacy and safety of Shenkang injection in treating diabetic nephropathy. METHODS: We will search 7 literature databases including PubMed, EMBASE, Cochrane Library, Sinomed, Chinese National Knowledge Infrastructure, Wanfang, and VIP. Two trial registry platforms will also be searched. The time frame of the search will be from the inceptions of the databases to December 31, 2020. RCTs assessing Shenkang injection combined with basic treatments versus basic treatments alone for treating diabetic nephropathy will be included. The risk of bias within the individual RCTs will be evaluated using criteria proposed by the Cochrane Handbook 5.1.0. The primary outcomes to be investigated are glomerular filtration rate and serum creatinine; the secondary outcome will include 24-hour urine albumin excretion rate, blood urea nitrogen, fasting blood glucose, postprandial blood glucose, hemoglobin A1c, total cholesterol, triglyceride, response to treatment, and incidence of adverse events. The effect data of individual RCTs by performing random-effects model meta-analysis. Statistical heterogeneity will be measured by the Cochran Q test and I-squared statistics. Three subgroup analyses, set based on clinical experience, will be performed to explore the sources of heterogeneity. Sensitivity analyses excluding RCTs with high risk of bias and using fixed effect model will be done to test the robustness of the meta-analytic results. Publication bias across included RCTs will be evaluated by funnel plots and Egger test. RESULTS: This study will provide systematic review on the efficacy and safety of Shenkang Injection as adjuvant therapy in patients with diabetic nephropathy by rigorous quality assessment and reasonable data synthesis. The results will be submitted to a peer-reviewed journal for publication. CONCLUSION: This systematic review will provide the best evidence currently on Shenkang Injection as adjuvant therapy in patients with diabetic nephropathy. INPLASY REGISTRATION NUMBER: INPLASY2020110014.

Autophagy-Sirt3 axis decelerates hematopoietic aging.

Autophagy suppresses mitochondrial metabolism to preserve hematopoietic stem cells (HSCs) in mice. However, the mechanism by which autophagy regulates hematopoietic aging, in particular in humans, has largely been unexplored. Here, we demonstrate that reduction of autophagy in both hematopoietic cells and their stem cells is associated with aged hematopoiesis in human population. Mechanistically, autophagy delays hematopoietic aging by activating the downstream expression of Sirt3, a key mitochondrial protein capable of rejuvenating blood. Sirt3 is the most abundant Sirtuin family member in HSC-enriched population, though it declines as the capacity for autophagy deteriorates with aging. Activation of autophagy upregulates Sirt3 in wild-type mice, whereas in autophagy-defective mice, Sirt3 expression is crippled in the entire hematopoietic hierarchy, but forced expression of Sirt3 in HSC-enriched cells reduces oxidative stress and prevents accelerated hematopoietic aging from autophagy defect. Importantly, the upregulation of Sirt3 by manipulation of autophagy is validated in human HSC-enriched cells. Thus, our results identify an autophagy-Sirt3 axis in regulating hematopoietic aging and suggest a possible interventional solution to human blood rejuvenation via activation of the axis.

Heat-sensitive moxibustion self-administration in patients in the community with primary hypertension: A protocol for a multi-center, pragmatic, non-randomized trial.

BACKGROUND: Although the efficacy of antihypertensive drugs has been well established for primary hypertension, their effectiveness is always limited by side effects and poor compliance. Heat-sensitive moxibustion is an innovative acupoint stimulation therapy that is promising as a community health care intervention for hypertension. AIMS: This study aims to evaluate the pragmatic effectiveness and safety of heat-sensitive moxibustion self-administration by patients in the community with primary hypertension. METHODS: This study will adopt a multi-center, pragmatic, nonrandomized design. Six hundred patients with primary hypertension will be recruited from 4 communities. Each patient will choose to either receive heat-sensitive moxibustion self-administration + original antihypertensive drugs or maintain their original antihypertensive drugs without heat-sensitive moxibustion for 1 year. EXPECTED OUTCOMES: The primary outcome will be changes in systolic and diastolic blood pressures and the percentage changes in the doses of antihypertensive drugs. The secondary outcomes will be changes in quality of life assessed by a validated patient-reported outcome scale and the levels of fasting blood glucose, glycated hemoglobin, total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, urinary albumin, and serum creatinine. The proportion of patients with poor compliance with the heat-sensitive moxibustion regimen will also be evaluated as a secondary outcome. The safety of heat-sensitive moxibustion will be considered by analyzing the incidence of all and serious adverse events and their correlation with heat-sensitive moxibustion. DISCUSSION: The findings of this study will provide pragmatic evidence for heat-sensitive moxibustion self-administration in patients in the community with primary hypertension and may also establish an ethical basis for further randomized controlled trials. TRIAL REGISTRATION: The protocol of this trial was registered in ClinicalTrials.gov at May 11, 2020 (No. NCT04381520).

Metabolic flux and transcriptome analyses provide insights into the mechanism underlying zinc sulfate improved ß-1,3-D-glucan production by Aureobasidium pullulans.

The effects of zinc sulfate at various concentrations on ß-1,3-D-glucan (ß-glucan) and pullulan production were investigated in flasks, and 0.1 g/L zinc sulfate was found to be the optimum concentration favoring increased ß-glucan production. When batch culture of Aureobasidium pullulans CCTCC M 2012259 with 0.1 g/L zinc sulfate was carried out, the maximum dry biomass decreased by 16.9% while ß-glucan production significantly increased by 120.5%, compared to results obtained from the control without zinc sulfate addition. To reveal the mechanism underlying zinc sulfate improved ß-glucan production, both metabolic flux analysis and RNA-seq analysis were performed. The results indicated that zinc sulfate decreased carbon flux towards biomass formation and ATP supply, down-regulated genes associated with membrane part and cellular components organization, leading to a decrease in dry cell weight. However, zinc sulfate increased metabolic flux towards ß-glucan biosynthesis, up-regulated genes related to glycan biosynthesis and nucleotide metabolism, resulting in improved ß-glucan production. This study provides insights into the changes in the metabolism of A. pullulans in response to zinc sulfate, and can serve as a valuable reference of genetic information for improving the production of polysaccharides through metabolic engineering.

Correction: The lipogenic LXR-SREBF1 signaling pathway controls cancer cell DNA repair and apoptosis and is a vulnerable point of malignant tumors for cancer therapy.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The lipogenic LXR-SREBF1 signaling pathway controls cancer cell DNA repair and apoptosis and is a vulnerable point of malignant tumors for cancer therapy.

Cancer cells are defective in DNA repair, so they experience increased DNA strand breaks, genome instability, gene mutagenesis, and tumorigenicity; however, multiple classic DNA repair genes and pathways are strongly activated in malignant tumor cells to compensate for the DNA repair deficiency and gain an apoptosis resistance. The mechanisms underlying this phenomenon in cancer are unclear. We speculate that a key DNA repair gene or signaling pathway in cancer has not yet been recognized. Here, we show that the lipogenic liver X receptor (LXR)-sterol response element binding factor-1 (SREBF1) axis controls the transcription of a key DNA repair gene polynucleotide kinase/phosphatase (PNKP), thereby governing cancer cell DNA repair and apoptosis. Notably, the PNKP levels were significantly reduced in 95% of human pancreatic cancer (PC) patients, particularly deep reduction for sixfold in all of the advanced-stage PC cases. PNKP is also deficient in three other types of cancer that we examined. In addition, the expression of LXRs and SREBF1 was significantly reduced in the tumor tissues from human PC patients compared with the adjacent normal tissues. The newly identified LXR-SREBF1-PNKP signaling pathway is deficient in PC, and the defect in the pathway contributes to the DNA repair deficiency in the cancer. Strikingly, further diminution of the vulnerable LXR-SREBF1-PNKP signaling pathway using a small molecule triptonide, a new LXR antagonist identified in this investigation, at a concentration of 8 nM robustly activated tumor-suppressor p53 and readily elevated cancer cell DNA strand breaks over an apoptotic threshold, and selectively induced PC cell apoptosis, resulting in almost complete elimination of tumors in xenograft mice without obvious complications. Our findings provide new insight into DNA repair and apoptosis in cancer, and offer a new platform for developing novel anticancer therapeutics.

Transcriptome analysis reveals the mechanism underlying improved glutathione biosynthesis and secretion in Candida utilis during selenium enrichment.

The effect of sodium selenite on batch culture of Candida utilis CCTCC M 209298 was investigated. Cell growth was inhibited while glutathione biosynthesis and secretion were improved during selenium enrichment. To reveal the mechanism underlying the decrease in biomass and the increase in glutathione, both metabolic flux analysis of key intermediates involved in glutathione metabolic pathway and transcriptome analysis of C. utilis by RNA-seq were carried out for selenized cells and the control without selenium enrichment. Results indicated that sodium selenite decreased carbon fluxes towards biomass but increased fluxes towards amino acids for the biosynthesis of glutathione and related amino acids. Selenium enrichment down-regulated a large number of genes involved in cell components and the cell cycle, resulting in decreased biomass as well as increased cell permeability. Moreover, several genes associated with transportation, binding, and mitochondrial and ribosomal functions for energy metabolism and protein synthesis were up-regulated in the presence of sodium selenite. All of these results disclosed the physiological response of C. utilis to sodium selenite.

Changes in cerebral glucose metabolism after acupuncture at KI3 in spontaneously hypertensive rats: a positron emission tomography study.

OBJECTIVE: The aim of this study was to explore the effect of acupuncture stimulation at KI3 on brain glucose metabolism in spontaneously hypertensive rats (SHRs). METHODS: Brain glucose metabolism in SHRs after acupuncture stimulation at KI3 was detected using 18F-2-fluorodeoxy-D-glucose positron emission tomography (18F-FDG-PET). SHRs were randomly divided into three groups: no treatment (SHR group); acupuncture at KI3 (KI3 group); and sham acupuncture (Sham group). Wistar Kyoto (WKY) rats were used as a normal blood pressure (BP) control group. Rats were subjected to 10 min of acupuncture once a day for 7 days. BP and positron emission tomography-computed tomography (PET-CT) were measured after the first acupuncture session and after 7 days of treatment. RESULTS: The results showed that BP was lower in the KI3 group than in the SHR group, both 30-60 min after the first acupuncture session and 24-48 h after the 7-day treatment. Compared with the WKY group, the SHR group had lower glucose metabolism in the motor cortex, sensory cortex, basal ganglia, corpus callosum, caudate putamen, and visual cortex. Compared with the untreated/sham-treated SHR control groups, cerebral glucose metabolism was lower in the medulla oblongata, thalamus, dorsal thalamus, orbital cortex, and hypothalamus after acupuncture at KI3, while it was higher in the olfactory cortex and inferior phrenic muscle. CONCLUSION: Our results show that, in SHRs, needling at KI3 reduces high BP, most likely by altering the activation of cerebral regions.

Impact of Morphological Characteristics of Green Roofs on Pedestrian Cooling in Subtropical Climates.

Growing and densifying cities set a challenge for preserving and enhancing green spaces to cool urban spaces. Green roofs, involving the planting of vegetation on rooftops, are regarded as an alternative approach to enhancing urban greenery and urban cooling. For better cooling performances, it is essential to reasonably configure green roofs, especially in real and complex neighborhoods. Therefore, the aim of this paper is to investigate the impact of morphological characteristics of green roofs on pedestrian cooling in real and complex neighborhoods. In specific, based on an ENVI-met model, we studied the effect of greening layout, coverage ratio, vegetation height, and building height on pedestrian air temperature reduction in the tropical city of Hangzhou, China. Results indicate green roofs could generate moderate effects on pedestrian air temperature reduction (around 0.10⁻0.30 °C), while achieving a cooling performance of 0.82 °C. Green roofs in upwind zones were able to generate the most favorable cooling performance, while green roofs in downwind zones made slight differences to pedestrian thermal environments. Green roofs with a low coverage ratio were not useful for lowering pedestrian temperature, and a greening coverage ratio of 25⁻75% in upwind zones was cost-effective in real neighborhoods. Locations that were horizontally close to green roofs enjoyed better cooling performances. Increasing vegetation height could strengthen cooling effects of green roofs, while an increase in building height weakened the cooling performance. Nevertheless, higher building height could enhance pedestrian cooling performances because of building shading effects. In addition, because of wind effects and building shading, building height limits for the cooling performance of green roofs could be higher than 60 m.

Disruption of por1 gene in Candida utilis improves co-production of S-adenosylmethionine and glutathione.

The por1 gene encoding one of the mitochondrial porin channels in C. utilis CCTCC M 209298 was disrupted using a homologous recombination method. The co-production of S-adenosylmethionine (SAM) and glutathione (GSH) in the mutant C. utilis Δpor1 increased by 34.9% and 25.1%, respectively, during batch and fed-batch fermentation, relative to the parental strain. The average oxygen consumption rate, activities of key enzymes involved in SAM and GSH biosynthesis, levels of intracellular cofactors such as NADH and ATP, and carbon fluxes of key metabolites were compared between the parental strain and the Δpor1 mutant. The disruption of por1 gene increased the rate of mitochondrial respiration, increased the activities of both methionine adenosyltransferase and γ-glutamylcysteine synthetase, and enhanced the supply of energy and substrates for SAM and GSH biosynthesis, all of which favored the overproduction of SAM and GSH in the Δpor1 mutant.

Improved S-adenosylmethionine and glutathione biosynthesis by heterologous expression of an ATP6 gene in Candida utilis.

ATP is indispensable to the biosynthesis of both S-adenosylmethionine (SAM) and glutathione (GSH) in yeast cells. To improve ATP supply for overproduction of SAM and GSH in Candida utilis CCTCC M 209298, an exogenous ATP6 gene from Arabidopsis thaliana was expressed in the parental strain to construct the mutant C. utilis ATP6 by genomic integration. The maximal production of SAM and GSH in the mutant increased by 46.6 and 28.7%, respectively, when compared with those obtained in the parental strain. The mechanism underlying improved SAM and GSH biosynthesis by exogenous ATP6 gene expression revealed that the mutant had higher activities of key enzymes involved in SAM and GSH biosynthesis as well as energy metabolism. Increased NADH availability and F0 F1 -ATPase activity subsequently resulted in improved ATP regeneration and intracellular ATP supply for SAM and GSH overproduction. The present study not only developed an effective method for improving SAM and GSH biosynthesis by energy metabolism regulation, but also offered a novel approach for efficient production of similar energy-consuming products in eukaryotic cells.

Chinese C allele carriers of the ERCC5 rs1047768 polymorphism are more sensitive to platinum-based chemotherapy: a meta-analysis.

It is suspected that ERCC5 rs1047768 and rs17655 polymorphisms influence the response to platinum-based chemotherapy. This meta-analysis was performed to summarize the scattered evidence regarding the association between these two polymorphisms and sensitivity to platinum-based treatment. Thirteen studies were included after a comprehensive literature search. The pooled odds ratios and 95% confidence intervals suggested that the C allele of the ERCC5 rs1047768 polymorphism is associated with elevated sensitivity to platinating agents, especially for Chinese patients. However, no difference among rs17655 genotypes could be detected.

The mechanism of improved intracellular organic selenium and glutathione contents in selenium-enriched Candida utilis by acid stress.

Batch culture of Candida utilis CCTCC M 209298 for the preparation of selenium (Se)-enriched yeast was carried out under different pH conditions, and maximal intracellular organic Se and glutathione (GSH) contents were obtained in a moderate acid stress environment (pH 3.5). In order to elucidate the physiological mechanism of improved performance of Se-enriched yeast by acid stress, assays of the key enzymes involved in GSH biosynthesis and determinations of energy supply and regeneration were performed. The results indicated that moderate acid stress increased the activity of γ-glutamylcysteine synthetase and the ratios of NADH/NAD+ and ATP/ADP, although no significant changes in intracellular pH were observed. In addition, the molecular mechanism of moderate acid stress favoring the improvement of Se-yeast performance was revealed by comparing whole transcriptomes of yeast cells cultured at pH 3.5 and 5.5. Comparative analysis of RNA-Seq data indicated that 882 genes were significantly up-regulated by moderate acid stress. Functional annotation of the up-regulated genes based on gene ontology and the Kyoto Encyclopedia of Genes and Genome (KEGG) pathway showed that these genes are involved in ATP synthesis and sulfur metabolism, including the biosynthesis of methionine, cysteine, and GSH in yeast cells. Increased intracellular ATP supply and more amounts of sulfur-containing substances in turn contributed to Na2SeO3 assimilation and biotransformation, which ultimately improved the performance of the Se-enriched C. utilis.

Copper sulfate improves pullulan production by bioconversion using whole cells of Aureobasidium pullulans as the catalyst.

The effects of mineral salts on pullulan production by bioconversion using whole cells of Aureobasidium pullulans CCTCC M 2012259 as the catalyst were investigated. Copper sulfate (CuSO4) improved pullulan production by 36.2% and 42.3% when added at the optimum concentration of 0.2mg/L to the bioconversion broth or seed medium, respectively, as compared with controls without CuSO4 addition. Pullulan production was further enhanced when CuSO4 was added to both seed medium and bioconversion broth simultaneously. In order to probe the mechanism of CuSO4 improvement, cell viability, membrane integrity, intracellular adenosine triphosphate (ATP) levels and the activities of key enzymes involved in pullulan biosynthesis were determined. As a result, CuSO4 increased the activities of key biosynthetic enzymes, maintained intracellular ATP at a higher level, and accelerated the rate of pullulan secretion, all of which contributed to improved pullulan production by bioconversion.