Fermentation quality of herbal tea residue and its application in fattening cattle under heat stress.

BACKGROUND: Herbal tea residue (HTR) is generally considered to be the waste of herbal tea beverage production while it still retains rich nutrients and active substances. The main aim of the present study was to investigate the effect of fermentation technology on improving the quality of HTRs, and focus on the fermented HTR-induced alleviation of summer heat stress in fattening cattle. RESULTS: In this study, the waste HTR was fermented and then fed to a total of 45 fattening cattle that were divided into 3 groups (fermented HTR replaced 0, 15, 30% of the forage component of the diet), and the feeding experiment was lasted for 40 days. The physiological indexes, growth performance and fecal microbiota of fattening cattle were evaluated and results showed that fermented HTR could effectively reduce the respiratory rate and rectal temperature of fattening cattle under heat stress, increase the daily feed intake and daily gain, and improve the antioxidant content and blood immune index. In addition, we studied the fecal microbiota composition of 6 fattening cattle in control and 30% HTR substitution groups and found fermented HTR significantly changed the composition of fecal microbiota and increased microbial diversity, and correlation analysis suggested that the bacteria were closely related to fecal SCFA levels of fattening cattle under heat stress. CONCLUSIONS: In this study, fermented HTR replaced 30% of the forage component of the diet that can change the intestine microorganisms, maintain health and alleviate the heat stress of fattening cattle.

Responses of Escherichia coli and Listeria monocytogenes to ozone treatment on non-host tomato: Efficacy of intervention and evidence of induced acclimation.

Because of the continuous rise of foodborne illnesses caused by the consumption of raw fruits and vegetables, effective post-harvest anti-microbial strategies are necessary. The aim of this study was to evaluate the anti-microbial efficacy of ozone (O3) against two common causes of fresh produce contamination, the Gram-negative Escherichia coli O157:H7 and Gram-positive Listeria monocytogenes, and to relate its effects to potential mechanisms of xenobiosis by transcriptional network modeling. The study on non-host tomato environment correlated the dose × time aspects of xenobiosis by examining the correlation between bacterial survival in terms of log-reduction and defense responses at the level of gene expression. In E. coli, low (1 µg O3/g of fruit) and moderate (2 µg O3/g of fruit) doses caused insignificant reduction in survival, while high dose (3 µg/g of fruit) caused significant reduction in survival in a time-dependent manner. In L. monocytogenes, moderate dose caused significant reduction even with short-duration exposure. Distinct responses to O3 xenobiosis between E. coli and L. monocytogenes are likely related to differences in membrane and cytoplasmic structure and components. Transcriptome profiling by RNA-Seq showed that primary defenses in E. coli were attenuated after exposure to a low dose, while the responses at moderate dose were characterized by massive upregulation of pathogenesis and stress-related genes, which implied the activation of defense responses. More genes were downregulated during the first hour at high dose, with a large number of such genes getting significantly upregulated after 2 hr and 3 hr. This trend suggests that prolonged exposure led to potential adaptation. In contrast, massive downregulation of genes was observed in L. monocytogenes regardless of dose and exposure duration, implying a mechanism of defense distinct from that of E. coli. The nature of bacterial responses revealed by this study should guide the selection of xenobiotic agents for eliminating bacterial contamination on fresh produce without overlooking the potential risks of adaptation.

Effects of Ejiao peptide-iron chelates on intestinal inflammation and gut microbiota in iron deficiency anemic mice.

Iron deficiency is a global nutritional problem that adversely affects the functional regulation of the immune system. In the process of treatment through iron supplementation, the problem of excessive iron intake often occurs, which increases the level of inflammation in the body. Excessive iron can also lead to an increase in intestinal iron-requiring pathogenic bacteria and an imbalance of intestinal flora. In this study, we aim to explore the effect of Ejiao peptide-iron (EPI) chelates on the intestinal flora and inflammation of ICR mice having iron-deficiency anemia (IDA). The mice were given low, medium, and high doses of EPI and FeSO4 (1.0, 2.0 and 3.0 mg Fe per kg weight, respectively) daily for 4 weeks by intragastric administration. IDA mice showed increased inflammation levels and decreased sIgA secretion, which were restored after intervention with EPI at different doses. Intestinal mucosal ulcers, inflammatory cell infiltration, and oxidative stress in the colon tissue were reduced, and intestinal permeability was improved. Furthermore, 16S rDNA gene sequencing revealed that EPI increased microbial diversity and richness, changing the community structure, therefore, alleviating microbiota dysbiosis caused by IDA (e.g. the proportion of Firmicutes/Bacteroides). Different from the traditional iron supplement FeSO4, when the pathogenic bacteria (e.g. Helicobacter and Erysipelatoclostridium) increase and the beneficial bacteria (e.g. Bifidobacterium and Blautia) decrease at high doses, EPI shows higher safety at a high dose, thereby maintaining a healthier intestinal homeostasis.

Multiplex suppression of four quadruplet codons via tRNA directed evolution.

Genetic code expansion technologies supplement the natural codon repertoire with assignable variants in vivo, but are often limited by heterologous translational components and low suppression efficiencies. Here, we explore engineered Escherichia coli tRNAs supporting quadruplet codon translation by first developing a library-cross-library selection to nominate quadruplet codon-anticodon pairs. We extend our findings using a phage-assisted continuous evolution strategy for quadruplet-decoding tRNA evolution (qtRNA-PACE) that improved quadruplet codon translation efficiencies up to 80-fold. Evolved qtRNAs appear to maintain codon-anticodon base pairing, are typically aminoacylated by their cognate tRNA synthetases, and enable processive translation of adjacent quadruplet codons. Using these components, we showcase the multiplexed decoding of up to four unique quadruplet codons by their corresponding qtRNAs in a single reporter. Cumulatively, our findings highlight how E. coli tRNAs can be engineered, evolved, and combined to decode quadruplet codons, portending future developments towards an exclusively quadruplet codon translation system.

Probiotic supplements alleviate gestational diabetes mellitus by restoring the diversity of gut microbiota: a study based on 16S rRNA sequencing.

Probiotics effectively prevent and improve metabolic diseases such as diabetes by regulating the intestinal microenvironment and gut microbiota. However, the effects of probiotics in gestational diabetes mellitus are not clear. Here, we showed that probiotic supplements significantly improved fasting blood glucose in a gestational diabetes mellitus rat model. To further understand the mechanisms of probiotics in gestational diabetes mellitus, the gut microbiota were analyzed via 16S rRNA sequencing. We found that compared with the normal pregnant group, the gestational diabetes mellitus rats had decreased diversity of gut microbiota. Moreover, probiotic supplementation restored the diversity of the gut microbiota in gestational diabetes mellitus rats, and the gut microbiota structure tended to be similar to that of normal pregnant rats. In particular, compared with gestational diabetes mellitus rats, the abundance of Firmicutes and Actinobacteria was higher after probiotic supplementation. Furthermore, activating carbohydrate metabolism and membrane transport pathways may be involved in the potential mechanisms by which probiotic supplements alleviate gestational diabetes mellitus. Overall, our results suggested that probiotic supplementation might be a novel approach to restore the gut microbiota of gestational diabetes mellitus rats and provided an experimental evidence for the use of probiotic supplements to treat gestational diabetes mellitus.

Analysis of the Manganese and MntR Regulon in Corynebacterium diphtheriae.

Corynebacterium diphtheriae is the causative agent of a severe respiratory disease in humans. The bacterial systems required for infection are poorly understood, but the acquisition of metals such as manganese (Mn) is likely critical for host colonization. MntR is an Mn-dependent transcriptional regulator in C. diphtheriae that represses the expression of the mntABCD genes, which encode a putative ABC metal transporter. However, other targets of Mn and MntR regulation in C. diphtheriae have not been identified. In this study, we use comparisons between the gene expression profiles of wild-type C. diphtheriae strain 1737 grown without or with Mn supplementation and comparisons of gene expression between the wild type and an mntR deletion mutant to characterize the C. diphtheriae Mn and MntR regulon. MntR was observed to both repress and induce various target genes in an Mn-dependent manner. Genes induced by MntR include the Mn-superoxide dismutase, sodA, and the putative ABC transporter locus, iutABCD. DNA binding studies showed that MntR interacts with the promoter regions for several genes identified in the expression study, and a 17-bp consensus MntR DNA binding site was identified. We found that an mntR mutant displayed increased sensitivity to Mn and cadmium that could be alleviated by the additional deletion of the mntABCD transport locus, providing evidence that the MntABCD transporter functions as an Mn uptake system in C. diphtheriae. The findings in this study further our understanding of metal uptake systems and global metal regulatory networks in this important human pathogen. IMPORTANCE Mechanisms for metal scavenging are critical to the survival and success of bacterial pathogens, including Corynebacterium diphtheriae. Metal import systems in pathogenic bacteria have been studied as possible vaccine components due to high conservation, critical functionality, and surface localization. In this study, we expand our understanding of the genes controlled by the global manganese regulator, MntR. We determined a role for the MntABCD transporter in manganese import using evidence from manganese and cadmium toxicity assays. Understanding the nutritional requirements of C. diphtheriae and the tools used to acquire essential metals will aid in the development of future vaccines.

The biological regulatory activities of Flammulina velutipes polysaccharide in mice intestinal microbiota, immune repertoire and heart transcriptome.

The effects of a novel Flammulina velutipes polysaccharide (FVP) on intestinal microbiota, immune repertoire and heart transcriptome were investigated in this study. The results showed that FVP treatment could effectively regulate the abundance of colonic microbiota. And FVP exhibited obvious immunoregulatory effect by influencing V gene and J gene fragments usage on TCRα chain. The usage frequency of TRBV1, TRBJ1-6 and TRBJ1-5 were significantly altered, and 41 V-J pairs were identified with obvious difference after FVP treatment. Furthermore, the mRNA of mice heart was analyzed by transcriptome assay. Total 525 genes and 1587 mRNA were significantly changed after FVP treatment. KEGG annotation indicated that the up-regulated mRNA was enriched in 17 pathways including adherens junction, mTOR signaling pathway, insulin signaling pathway, mitophagy, tight junction, PPAR signaling pathway and TNF signaling pathway, etc. Meanwhile, the down-regulated mRNA was gathered in AMPK signaling pathway, metabolism of xenobiotics by cytochrome P450, apelin signaling pathway, PPAR signaling pathway, PI3K-Akt signaling pathway, insulin signaling pathway, cardiac muscle contraction, adrenergic signaling in cardiomyocytes, Fc gamma R-mediated phagocytosis, etc. The great potential exhibited by FVP could make it an ideal candidate as complementary medicine or functional food for promotion of health.

Carotenoid Nostoxanthin Production by Sphingomonas sp. SG73 Isolated from Deep Sea Sediment.

Carotenoids are used commercially for dietary supplements, cosmetics, and pharmaceuticals because of their antioxidant activity. In this study, colored microorganisms were isolated from deep sea sediment that had been collected from Suruga Bay, Shizuoka, Japan. One strain was found to be a pure yellow carotenoid producer, and the strain was identified as Sphingomonas sp. (Proteobacteria) by 16S rRNA gene sequence analysis; members of this genus are commonly isolated from air, the human body, and marine environments. The carotenoid was identified as nostoxanthin ((2,3,2',3')-ß,ß-carotene-2,3,2',3'-tetrol) by mass spectrometry (MS), MS/MS, and ultraviolet-visible absorption spectroscopy (UV-Vis). Nostoxanthin is a poly-hydroxy yellow carotenoid isolated from some photosynthetic bacteria, including some species of Cyanobacteria. The strain Sphingomonas sp. SG73 produced highly pure nostoxanthin of approximately 97% (area%) of the total carotenoid production, and the strain was halophilic and tolerant to 1.5-fold higher salt concentration as compared with seawater. When grown in 1.8% artificial sea salt, nostoxanthin production increased by 2.5-fold as compared with production without artificial sea salt. These results indicate that Sphingomonas sp. SG73 is an efficient producer of nostoxanthin, and the strain is ideal for carotenoid production using marine water because of its compatibility with sea salt.

Consumption of soybean or olive oil at recommended concentrations increased the intestinal microbiota diversity and insulin sensitivity and prevented fatty liver compared to the effects of coconut oil.

Diets rich in mono or polyunsaturated fats have been associated with a healthy phenotype, but there is controversial evidence about coconut oil (CO), which is rich in saturated medium-chain fatty acids. Therefore, the purpose of the present work was to study whether different types of oils rich in polyunsaturated (soybean oil, SO), monounsaturated (olive oil, OO), or saturated fatty acids (coconut oil, CO) can regulate the gut microbiota, insulin sensitivity, inflammation, mitochondrial function in wild type and PPARα KO mice. The group that received SO showed the highest microbial diversity, increase in Akkermansia muciniphila, high insulin sensitivity and low grade inflammation, The OO group showed similar insulin sensitivity and insulin signaling than SO, increase in Bifidobacterium, increase in fatty acid oxidation and low grade inflammation. The CO consumption led to the lowest bacterial diversity, a 9-fold increase in the LPS concentration leading to metabolic endotoxemia, hepatic steatosis, increased lipogenesis, highest LDL-cholesterol concentration and the lowest respiratory capacity and fatty acid oxidation in the mitochondria. The absence of PPARα decreased alpha diversity and increased LPS concentration particularly in the CO group, and increased insulin sensitivity in the groups fed SO or OO. These results indicate that consuming mono or polyunsaturated fatty acids produced health benefits at the recommended intake but a high concentration of oils (three times the recommended oil intake in rodents) significantly decreased the microbial alpha-diversity independent of the type of oil.

The Serine Biosynthesis of Paenibacillus polymyxa WLY78 Is Regulated by the T-Box Riboswitch.

Serine is important for nearly all microorganisms in protein and downstream amino acids synthesis, however, the effect of serine on growth and nitrogen fixation was not completely clear in many bacteria, besides, the regulatory mode of serine remains to be fully established. In this study, we demonstrated that L-serine is essential for growth and nitrogen fixation of Paenibacillus polymyxa WLY78, but high concentrations of L-serine inhibit growth, nitrogenase activity, and nifH expression. Then, we revealed that expression of the serA whose gene product catalyzes the first reaction in the serine biosynthetic pathway is regulated by the T-box riboswitch regulatory system. The 508 bp mRNA leader region upstream of the serA coding region contains a 280 bp T-box riboswitch. The secondary structure of the T-box riboswitch with several conserved features: three stem-loop structures, a 14-bp T-box sequence, and an intrinsic transcriptional terminator, is predicted. Mutation and the transcriptional leader-lacZ fusions experiments revealed that the specifier codon of serine is AGC (complementary to the anticodon sequence of tRNAser). qRT-PCR showed that transcription of serA is induced by serine starvation, whereas deletion of the specifier codon resulted in nearly no expression of serA. Deletion of the terminator sequence or mutation of the continuous seven T following the terminator led to constitutive expression of serA. The data indicated that the T-box riboswitch, a noncoding RNA segment in the leader region, regulates expression of serA by a transcription antitermination mechanism.

Effects of multi-species probiotic supplementation on alcohol metabolism in rats.

Probiotics are known to protect against liver damage induced by the alcohol and acetaldehyde accumulation associated with alcohol intake. However, there have been few studies of the direct effect of probiotics on alcohol metabolism, and the types of probiotics that were previously analyzed were few in number. Here, we investigated the effects of 19 probiotic species on alcohol and acetaldehyde metabolism. Four probiotic species that had a relatively high tolerance to alcohol and metabolized alcohol and acetaldehyde effectively were identified: Lactobacillus gasseri CBT LGA1, Lactobacillus casei CBT LC5, Bifidobacterium lactis CBT BL3, and Bifidobacterium breve CBT BR3. These species also demonstrated high mRNA expression of alcohol and acetaldehyde dehydrogenases. ProAP4, a mixture of these four probiotics species and excipient, was then administered to rats for 2 weeks in advance of acute alcohol administration. The serum alcohol and acetaldehyde concentrations were significantly lower in the ProAP4-administered group than in the control and excipient groups. Thus, the administration of ProAP4, containing four probiotic species, quickly lowers blood alcohol and acetaldehyde concentrations in an alcohol and acetaldehyde dehydrogenasedependent manner. Furthermore, the serum alanine aminotransferase activity, which is indicative of liver damage, was significantly lower in the ProAP4 group than in the control group. The present findings suggest that ProAP4 may be an effective means of limiting alcohol-induced liver damage.

16S rRNA gene-based microbiome analysis identifies candidate bacterial strains that increase the storage time of potato tubers.

In the past, the potato plant microbiota and rhizosphere have been studied in detail to improve plant growth and fitness. However, less is known about the postharvest potato tuber microbiome and its role in storage stability. The storage stability of potatoes depends on genotype and storage conditions, but the soil in which tubers were grown could also play a role. To understand the ecology and functional role of the postharvest potato microbiota, we planted four potato varieties in five soil types and monitored them until the tubers started sprouting. During storage, the bacterial community of tubers was analysed by next-generation sequencing of the 16S rRNA gene amplicons. The potato tubers exhibited soil-dependent differences in sprouting behaviour. The statistical analysis revealed a strong shift of the tuber-associated bacterial community from harvest to dormancy break. By combining indicator species analysis and a correlation matrix, we predicted associations between members of the bacterial community and tuber sprouting behaviour. Based on this, we identified Flavobacterium sp. isolates, which were able to influence sprouting behaviour by inhibiting potato bud outgrowth.

Staphylococcus aureus lacking a functional MntABC manganese import system has increased resistance to copper.

S. aureus USA300 isolates utilize the copBL and copAZ gene products to prevent Cu intoxication. We created and examined a ΔcopAZ ΔcopBL mutant strain (cop-). The cop- strain was sensitive to Cu and accumulated intracellular Cu. We screened a transposon (Tn) mutant library in the cop- background and isolated strains with Tn insertions in the mntABC operon that permitted growth in the presence of Cu. The mutations were in mntA and they were recessive. Under the growth conditions utilized, MntABC functioned in manganese (Mn) import. When cultured with Cu, strains containing a mntA::Tn accumulated less Cu than the parent strain. Mn(II) supplementation improved growth when cop- was cultured with Cu and this phenotype was dependent upon the presence of MntR, which is a repressor of mntABC transcription. A ΔmntR strain had an increased Cu load and decreased growth in the presence of Cu, which was abrogated by the introduction of mntA::Tn. Over-expression of mntABC increased cellular Cu load and sensitivity to Cu. The presence of a mntA::Tn mutation protected iron-sulfur (FeS) enzymes from inactivation by Cu. The data presented are consistent with a model wherein defective MntABC results in decreased cellular Cu accumulation and protection to FeS enzymes from Cu poisoning.

Analysis of the developing gut microbiota in young dairy calves-impact of colostrum microbiota and gut disturbances.

The aim of this study was to characterize the colostrum and fecal microbiota in calves and to investigate whether fecal microbiota composition was related to colostrum microbiota or factors associated with calf health. Colostrum samples were collected in buckets after hand milking of 76 calving cows from 38 smallholder dairy farms. Fecal samples were taken directly from the rectum of 76 calves at birth and at 14 days age. The bacterial community structure in colostrum and feces was analyzed by terminal restriction fragment length polymorphism for all samples, and the microbial composition was determined by 16S rRNA gene amplicon sequencing for a subset of the samples (8 colostrum, 40 fecal samples). There was a significant difference in fecal microbiota composition between day 0 and day 14 samples, but no associations between the microbiota and average daily gain, birth weight, or transfer of passive immunity. At 14 days of age, Faecalibacterium and Butyricicoccus were prevalent in higher relative abundances in the gut of healthy calves compared to calves with diarrhea that had been treated with antimicrobials. Colostrum showed great variation in composition of microbiota but no association to fecal microbiota. This study provides the first insights into the composition of colostrum and fecal microbiota of young dairy calves in southern Vietnam and can form the basis for future more detailed studies.

A polyphenol-rich cranberry extract protects against endogenous exposure to persistent organic pollutants during weight loss in mice.

The dramatic rise in the global occurrence of obesity and associated diseases calls for new strategies to promote weight loss. However, while the beneficial effects of weight loss are well known, rapid loss of fat mass can also lead to the endogenous release of liposoluble molecules with potential harmful effects, such as persistent organic pollutants (POP). The aim of this study was to evaluate the impact of a polyphenol-rich cranberry extract (CE) on POP release and their potential deleterious effects during weight loss of obese mice. C57BL/6 J mice were fed an obesogenic diet with or without a mixture of POP for 12 weeks and then changed to a low-fat diet to induce weight loss and endogenous POP release. The POP-exposed mice were then separated in two groups during weight loss, receiving either CE or the vehicle. Unexpectedly, despite the higher fat loss in the CE-treated group, the circulating levels of POP were not enhanced in these mice. Moreover, glucose homeostasis was further improved during CE-induced weight loss, as revealed by lower fasting glycemia and improved glucose tolerance as compared to vehicle-treated mice. Interestingly, the CE extract also induced changes in the gut microbiota after weight loss in POP-exposed mice, including blooming of Parvibacter, a member of the Coriobacteriaceae family which has been predicted to play a role in xenobiotic metabolism. Our data thus suggests that the gut microbiota can be targeted by polyphenol-rich extracts to protect from increased POP exposure and their detrimental metabolic effects during rapid weight loss.

The Interactive Effects of Crude Oil and Corexit 9500 on Their Biodegradation in Arctic Seawater.

The risk of petroleum spills coupled with the potential application of chemical dispersants as a spill response strategy necessitates further understanding of the fate of oil and dispersants and their interactive effects during biodegradation. Using Arctic seawater mesocosms amended with either crude oil, Corexit 9500, or both together, we quantified the chemical losses of crude oil and Corexit 9500 and identified microbial taxa implicated in their biodegradation based on shifts in the microbial community structure over a 30-day time course. Chemical analyses included total petroleum hydrocarbons (TPH), n-alkanes, branched alkanes, and polycyclic aromatic hydrocarbons (PAHs) for oil loss and the surfactant components dioctyl sodium sulfosuccinate (DOSS), Span 80, Tween 80, Tween 85, and the DOSS metabolite ethylhexyl sulfosuccinate (EHSS) for Corexit loss. Changes to the microbial communities and identification of key taxa were determined by 16S rRNA gene amplicon sequencing. The nonionic surfactants of Corexit 9500 (Span 80 and Tweens 80 and 85) biodegraded rapidly, dropping to below the limits of detection within 5 days and prior to any detectable initiation of oil biodegradation. This resulted in no observable suppression of petroleum biodegradation in the presence of Corexit compared to that of oil alone. In contrast, biodegradation of DOSS was delayed in the presence of oil, based on the prolonged presence of DOSS and accumulation of the degradation intermediate EHSS that did not occur in the absence of oil. Microbial analyses revealed that oil and Corexit enriched different overall microbial communities, with the presence of both resulting in a community composition that shifted from one more similar to that of Corexit only to one reflecting the oil-only community over time, in parallel with the degradation of predominantly Corexit and then oil components. Some microbial taxa (Oleispira, Pseudofulvibacter, and Roseobacter) responded to either oil or Corexit, suggesting that some organisms may be capable of utilizing both substrates. Together, these findings reveal interactive effects of crude oil and Corexit 9500 on chemical losses and microbial communities as they biodegrade, providing further insight into their fate when copresent in the environment.IMPORTANCE Chemical dispersants such as Corexit 9500 are commonly used in oil spill response and are currently under consideration for use in the Arctic, where their fate and effects have not been well studied. This research was performed to determine the interactive effects of the copresence of crude oil and Corexit 9500 on the degradation of components from each mixture and the associated microbial community structure over time in Arctic seawater. These findings will help yield a better understanding of the biodegradability of dispersant components applied to an oil spill, the temporal microbial community response to dispersed oil, and the fundamental microbial ecology of organic contaminant biodegradation processes in the Arctic marine environment.

Plant growth promoting Pseudomonas aeruginosa from Valeriana wallichii displays antagonistic potential against three phytopathogenic fungi.

The soil nature and characterstics are directly related to the micro-organisms present, bio-mineralization process, plant type and thus having harmonius and interdependent relationships. Soil bacteria having antagonistic activity against phytopathogens, play an important role in root growth, overall plant growth and also their composition depends upon the plant species. Population explosion across globe has resulted in indiscriminate use of chemical fertilizers, fungicides and pesticides, thus posing serious risk to plant productivity and soil flora. Plant growth promoting rhizobacteria (PGPRs) are considered safer than chemical fertilizers as they are eco-friendly and sustain longer after colonization in rhizospheric soil. PGPRs are preferred as a green choice and acts as a superior biocontrol agents against phytopathogens. In the present study, a potential rhizobacteria, Pseudomonas aeruginosa (isolate-2) was isolated from the rhizosphere of a medicinal plant, Valeriana wallichi. The bacterial isolate exhibited qualitative tests for plant growth promoting determinatives. It was also subjected to in-vitro biocontrol activity against potential phytopathogens viz. Alternaria alternata, Aspergillus flavus and F. oxysporum. The antagonistic efficacy against F. oxysporum was 56.2% followed by Alternaria alternata to be 51.02%. The maximum inhibition of radial growth of F. oxysporum was 69.2%, Alternaria alternata (46.4%) and Aspergillus flavus (15%). The Pseudomonas aeruginosa exhibited plant growth promotion rhizobacterial activity which can be expoited as biofertilizers. This study deals with microbial revitalization strategy and offers promising solution as a biocontrol agent to enhance crop yield. Further, PGPRs research using the interdisciplinary approaches like biotechnology, nanotechnology etc. will unravel the molecular mechanisms which may be helpful for maximizing its potential in sustainable agriculture.

Suppression of High-Fat Diet-Induced Obesity by Platycodon Grandiflorus in Mice Is Linked to Changes in the Gut Microbiota.

BACKGROUND: The root of Platycodon grandiflorus (PG) has a long-standing tradition in the Asian diet and herbal medicine, because of its anti-inflammatory and antiobesity effects. Changes in the gut microbiota can have dietary effects on host health, which suggests a relation between the 2. OBJECTIVES: The aim of our study was to investigate the relation between PG-mediated suppression of obesity and the composition and functioning of the gut microbiota. METHODS: Six-week-old male C57BL/6J mice were fed either a control diet (CON, 10% kcal from fat), a high-fat diet (HFD, 60% kcal from fat), or a PG-supplemented HFD for 18 wk. PG was administered by oral gavage at 2 g · kg body weight-1 · d-1. Body weight and food intake were monitored. Lipid metabolism, inflammation, and intestinal barrier function were determined. Amplicon sequencing of the bacterial 16S ribosomal RNA gene was used to explore gut microbiota structure, and nontargeted metabolomics analysis was performed to investigate metabolite concentrations in fecal samples. RESULTS: We found that PG significantly ameliorated HFD-induced inflammation, recovered intestinal barrier integrity (reduced permeability by 39% , P = 0.008), reduced fat accumulation by 26% (P = 0.009), and changed the expression of key genes involved in the development of white adipose tissue (P < 0.05) in HFD-fed mice to similar levels in CON mice. Moreover, PG attenuated HFD-induced changes in the gut microbiota; it especially increased Allobaculum (7.3-fold, P = 0.002) relative to HFD, whereas CON was 15.2-fold of HFD (P = 0.002). These changes by PG were associated with an increase in the production of SCFAs (butyrate and propionate, P < 0.001) and other carbohydrate-related metabolites known to have a major role in disease suppression. CONCLUSIONS: Our study demonstrated that PG beneficially changed the gut microbiota and the gut metabolome in HFD-fed mice, and suggests that the antiobesity effects of PG may be mediated via changes in gut microbiota composition and metabolic activity.

Dendrobium officinale Kimura et Migo and American ginseng mixture: A Chinese herbal formulation for gut microbiota modulation.

Dendrobium officinale Kimura et Migo (D. officinale) is a famous traditional Chinese medicine (TCM). A mixture of D. officinale and American ginseng has been shown to enhance cell-mediated immunity, humoral immunity, and monocyte/macrophage functions in mice. Here, the effects of a D. officinale and American ginseng mixture on the structure of gut microbial community in dogs were examined using high-throughput 16S rRNA gene amplicon sequencing. The data revealed that while the mixture did not change the diversity of gut microbial community significantly, differences among individuals were significantly reduced. Furthermore, the mixture-responsive operational taxonomic units (OTUs) exhibited a phase-dependent expression pattern. Fifty-five OTUs were found to exhibit a mixture-induced expression pattern, among which one third were short-chain fatty acid (SCFA)-producing genera and the others were probiotic genera included Lactobacillus spp., Sutterella, Alistipes, Anaerovorax, Bilophila, Coprococcus, Gordonibacter, Oscillibacter, among others. By contrast, 36% of the OTUs exhibiting a mixture-repressed expression pattern were disease-associated microorganisms, and six genera, namely Actinomyces, Escherichia/Shigella, Fusobacterium, Slackia, Streptococcus and Solobacterium, were associated with cancer. In addition, five genera were closely associated with diabetes, namely Collinsella, Rothia, Howardella, Slackia and Intestinibacter. Our results indicate that this D. officinale and American ginseng mixture may be used as a prebiotic agent to enhance SCFA-producing genera and prevent gut dysbiosis.

Characterization of a transcriptional TPP riboswitch in the human pathogen Neisseria meningitidis.

Increasing evidence has demonstrated that regulatory RNA elements such as riboswitches (RS) play a pivotal role in the fine-tuning of bacterial gene expression. In this study, we investigated and characterized a novel transcriptional thiamine pyrophosphate (TPP) RS in the obligate human pathogen N. meningitidis MC58 (serogroup B). This RS is located in the 5´ untranslated region upstream of thiC gene, encoding a protein involved in TPP biosynthesis, an essential cofactor for all living beings. Primer extension revealed the transcriptional start site of thiC. Northern blot analysis of thiC mRNA and reporter gene studies confirmed the presence of an active TPP-sensing RS. Expression patterns of the wild-type RS and site-specific mutants showed that it is an OFF switch that controls transcription elongation of thiC mRNA. Interestingly, the regulatory mechanism of the meningococcal thiC RS resembles the Gram-positive Bacillus subtilis thiC RS rather than the Gram-negative Escherichia coli thiC RS. Therefore, the meningococcal thiC RS represents a rare example of transcriptional RS in a Gram-negative bacterium. We further observed that the RS is actively involved in modulating gene expression in response to different growth media and to supplemented bacterial and eukaryotic cell lysates as possible sources of nutrients in the nasopharynx. Our results suggest that RS-mediated gene regulation could influence meningococcal fitness, through the fine-tuning of biosynthesis and scavenging of nutrients and cofactors, such as thiamine.