Label-free quantitative proteomic analysis of Lactobacillus fermentum NCDC 400 during bile salt exposure

Pre-clinical safety and toxicity assessment of Limosilactobacillus fermentum NCDC 400 in murine model

Comprehensive safety assessment of potential probiotic strains is crucial in the selection of risk-free strains for clinical translation. This study aimed to evaluate the biosafety of Limosilactobacillus fermentum NCDC 400, a potential probiotic strain, using oral toxicity tests in a Swiss albino mouse model. Mice were orally gavaged with low (108 CFU/mouse/day) and high (1010 CFU/mouse/day) doses of NCDC 400 for 14 (acute), 28 (subacute), and 90 (subchronic) days to assess behavioral, hematological, biochemical, immunological, and histological effects. The administration of NCDC 400 did not result in any observable adverse effects on general health parameters, including body weight, feed and water intake, and organ indices. Hematological and biochemical parameters, such as glucose, serum enzymes, urea, creatinine, serum minerals, total serum proteins, and lipid profile, remained largely unaffected by the test strain. Notably, NCDC 400 administration led to a significant reduction in harmful intestinal enzymes and improvement in gut health indices, as indicated by fecal pH, lactate, ammonia, and short-chain fatty acids. There were no instances of bacterial translocation of NCDC 400 to blood or extra-intestinal organs. Immune homeostasis was not adversely affected by repeated exposure to NCDC 400 in all three oral toxicity studies. Histopathological examination revealed no strain-related changes in various tissues. Based on these findings, a dose of 1010 CFU/mouse/day was considered as the No Observable Effect Level (NOEL) in healthy mice. In conclusion, this study demonstrates the safe and non-toxic behavior of L. fermentum NCDC 400. The results support and ensure the safety and suitability for clinical trials and eventual translation into clinical practice as potential probiotic.

Inorganic phosphate modifies stationary phase fitness and metabolic pathways in Lactiplantibacillus paraplantarum CRL 1905

Inorganic phosphate (Pi) concentration modulates polyphosphate (polyP) levels in diverse bacteria, affecting their physiology and survival. Lactiplantibacillus paraplantarum CRL 1905 is a lactic acid bacterium isolated from quinoa sourdough with biotechnological potential as starter, for initiating fermentation processes in food, and as antimicrobial-producing organism. The aim of this work was to evaluate the influence of the environmental Pi concentration on different physiological and molecular aspects of the CRL 1905 strain. Cells grown in a chemically defined medium containing high Pi (CDM + P) maintained elevated polyP levels up to late stationary phase and showed an enhanced bacterial survival and tolerance to oxidative stress. In Pi sufficiency condition (CDM-P), cells were ~ 25% longer than those grown in CDM + P, presented membrane vesicles and a ~ 3-fold higher capacity to form biofilm. Proteomic analysis indicated that proteins involved in the "carbohydrate transport and metabolism" and "energy production and conversion" categories were up-regulated in high Pi stationary phase cells, implying an active metabolism in this condition. On the other hand, stress-related chaperones and enzymes involved in cell surface modification were up-regulated in the CDM-P medium. Our results provide new insights to understand the CRL 1905 adaptations in response to differential Pi conditions. The adjustment of environmental Pi concentration constitutes a simple strategy to improve the cellular fitness of L. paraplantarum CRL 1905, which would benefit its potential as a microbial cell factory.

Acetyl-CoA Acetyltransferase 2 Confers Radioresistance by Inhibiting Ferroptosis in Esophageal Squamous Cell Carcinoma

PURPOSE

The overall survival of patients with esophageal squamous cell carcinoma (ESCC) is not high due to the lack of markers to evaluate concurrent chemoradiation therapy (CCRT) resistance. The aim of this study is to use proteomics to identify a protein related to radiation therapy resistance and explore its molecular mechanisms.

METHODS AND MATERIALS

Proteomic data for pretreatment biopsy tissues from 18 patients with ESCC who underwent CCRT (complete response [CR] group, n = 8; incomplete response [

RESULTS

Enrichment analysis of differentially expressed proteins (

CONCLUSION

ACAT2 overexpression confers radioresistance by inhibiting ferroptosis in ESCC, suggesting ACAT2 could be a potential biomarker of poor radiotherapeutic response and a therapeutic target for enhancing the radiosensitivity of ESCC.

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Affiliation(s)

Jinghua Heng Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China
Zhimao Li Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China
Luxin Liu The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, China
Zhenyuan Zheng Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China; The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, China; Guangdong Esophageal Cancer Research Institute, Shantou Subcenter, Cancer Research Center, Shantou University Medical College, Shantou, China
Yaqi Zheng Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China
Xiue Xu Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China
Liandi Liao Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China
Hongyao Xu Department of Radiation Oncology, Shantou Central Hospital, Shantou, China
Hecheng Huang Department of Radiation Oncology, Shantou Central Hospital, Shantou, China
Enmin Li The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, China.
Liyan Xu Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, China; Guangdong Esophageal Cancer Research Institute, Shantou Subcenter, Cancer Research Center, Shantou University Medical College, Shantou, China.

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Integrating Omics Technologies for a Comprehensive Understanding of the Microbiome and Its Impact on Cattle Production

Ruminant production holds a pivotal position within the global animal production and agricultural sectors. As population growth escalates, posing environmental challenges, a heightened emphasis is directed toward refining ruminant production systems. Recent investigations underscore the connection between the composition and functionality of the rumen microbiome and economically advantageous traits in cattle. Consequently, the development of innovative strategies to enhance cattle feed efficiency, while curbing environmental and financial burdens, becomes imperative. The advent of omics technologies has yielded fresh insights into metabolic health fluctuations in dairy cattle, consequently enhancing nutritional management practices. The pivotal role of the rumen microbiome in augmenting feeding efficiency by transforming low-quality feedstuffs into energy substrates for the host is underscored. This microbial community assumes focal importance within gut microbiome studies, contributing indispensably to plant fiber digestion, as well as influencing production and health variability in ruminants. Instances of compromised animal welfare can substantially modulate the microbiological composition of the rumen, thereby influencing production rates. A comprehensive global approach that targets both cattle and their rumen microbiota is paramount for enhancing feed efficiency and optimizing rumen fermentation processes. This review article underscores the factors that contribute to the establishment or restoration of the rumen microbiome post perturbations and the intricacies of host-microbiome interactions. We accentuate the elements responsible for responsible host-microbiome interactions and practical applications in the domains of animal health and production. Moreover, meticulous scrutiny of the microbiome and its consequential effects on cattle production systems greatly contributes to forging more sustainable and resilient food production systems, thereby mitigating the adverse environmental impact.

Transcriptome responses of lactic acid bacteria isolated from kimchi under hydrogen peroxide exposure

In this study, five species of lactic acid bacteria (LAB) isolated from kimchi were analyzed in terms of their potential antioxidant activity. Latilactobacillus curvatus WiKim38, Companilactobacillus allii WiKim39, and Lactococcus lactis WiKim0124 exhibited higher radical scavenging activity, reducing power, and lipid peroxidation inhibition than the reference strain and tolerated hydrogen peroxide (H₂O₂) exposure up to a concentration of 2.5 mM. To investigate the antioxidant mechanism of LAB strains, transcriptomic and proteomic signatures were compared between the H₂O₂-exposed and untreated group using RNA sequencing and two-dimensional protein gel electrophoresis. Across all LAB strains, cell membrane responses and metabolic processes were the most prominent in the main categories of gene ontology classification, indicating that cellular components and interactions play an important role in oxidative stress responses. Thus, LAB strains isolated from kimchi could be considered for potential use in functional food production and in antioxidant starter cultures.

Holistic analysis of lysine acetylation in aquaculture pathogenic bacteria Vibrio alginolyticus under bile salt stress

Lysine acetylation modification is a dynamic and reversible post-translational modification, which plays an important role in the metabolism and pathogenicity of pathogenic bacteria. Vibrio alginolyticus is a common pathogenic bacterium in aquaculture, and bile salt can trigger the expression of bacterial virulence. However, little is known about the function of lysine acetylation in V. alginolyticus under bile salt stress. In this study, 1,315 acetylated peptides on 689 proteins were identified in V. alginolyticus under bile salt stress by acetyl-lysine antibody enrichment and high-resolution mass spectrometry. Bioinformatics analysis found that the peptides motif ^****A^*Kac^**** and ^*******Kac^****A^* were highly conserved, and protein lysine acetylation was involved in regulating various cellular biological processes and maintaining the normal life activities of bacteria, such as ribosome, aminoacyl-tRNA biosynthesis, fatty acid metabolism, two-component system, and bacterial secretion system. Further, 22 acetylated proteins were also found to be related to the virulence of V. alginolyticus under bile salt stress through secretion system, chemotaxis and motility, and adherence. Finally, comparing un-treated and treated with bile salt stress lysine acetylated proteins, it was found that there were 240 overlapping proteins, and found amino sugar and nucleotide sugar metabolism, beta-Lactam resistance, fatty acid degradation, carbon metabolism, and microbial metabolism in diverse environments pathways were significantly enriched in bile salt stress alone. In conclusion, this study is a holistic analysis of lysine acetylation in V. alginolyticus under bile salt stress, especially many virulence factors have also acetylated.

Protective effect of probiotic and prebiotic fermented milk containing Lactobacillus fermentum against obesity-induced hepatic steatosis and inflammation

Obesity has reached epidemic proportions, with major economic and health implications. The complex pathophysiology of obesity explains the difficulty provided to health policy for its clinical management. Increasing data show that obesity and metabolic abnormalities are intimately connected to differences in consumption of probiotics, its relevance to gut microbiota activity and composition. The goal of this investigation was to assess the effect of oral delivery of indigenous probiotic Lactobacillus fermentum NCDC 400 and prebiotic fructo-oligosaccharide (FOS) on obesity-associated hepatic steatosis and inflammation produced by a high-fat diet (HFD). C57BL/6 mice treated with L. fermentum NCDC 400 either independently or in conjunction with FOS demonstrated reduced body weight and abdominal obesity after 24 weeks of treatment. Also, the anti-oxidative enzyme activity went down, and the inflammatory profile got better, with less fat getting into the hepatocytes. The lipid profile changed, with HDL cholesterol going up and LDL cholesterol and triglyceride levels going down. Further, L. fermentum NCDC 400 and FOS combinations decreased fasting glucose, gHbA1c, gastric inhibitory peptide, and insulin levels in mice fed with HFD, thus improving glucose homeostasis. Overall, consumption of L. fermentum NCDC 400 alone or its combinational effects had a protective role on obesity-associated hepatic steatosis. PRACTICAL APPLICATIONS: The potential indigenous probiotic Lactobacillus fermentum NCDC 400 and prebiotic FOS had a preventive role in obesity-induced hepatic steatosis and improves anti-oxidant and anti-inflammatory properties in HFD-fed obese mice. Our finding would be helpful to prevent obesity-associated hepatic steatosis and inflammation upon supplementation of pre- and pro-biotics (synbiotics).

Identification of Novel Bile Salt-Tolerant Genes in Lactobacillus Using Comparative Genomics and Its Application in the Rapid Screening of Tolerant Strains

Under bile salt treatment, strains display significant differences in their tolerance ability, suggesting the existence of diverse resistance mechanisms in Lactobacillus; however, the genes involved in this protective process are not fully understood. In this study, novel target genes associated with bile salt tolerance in Lactobacillus were identified using comparative genomics for PCR detection and the rapid screening of tolerant strains. The bile salt tolerance of 107 lactobacilli isolated from different origins was assessed, and 26 strains with comparatively large differences were selected for further comparative genomic analysis. Tolerant strains had 112 specific genes that were enriched in the phosphotransferase system, the two-component system, carbohydrate metabolism, and the ATP-binding cassette transporter. Six genes from Lactobacillus were cloned into the inducible lactobacillal expression vector pSIP403. Overexpression in the host strain increased its tolerance ability by 11.86-18.08%. The novel genes identified here can be used as targets to design primers for the rapid screening of bile salt-tolerant lactobacilli. Altogether, these results deepen our understanding of bile salt tolerance mechanisms in Lactobacillus and provide a basis for further rapid assessments of tolerant strains.

Dairy-Based Probiotic-Fermented Functional Foods: An Update on Their Health-Promoting Properties

Numerous studies have shown a link between the consumption of fermented dairy foods and improved health outcomes. Since the early 2000s, especially probiotic-based fermented functional foods, have had a revival in popularity, mostly as a consequence of claims made about their health benefits. Among them, fermented dairy foods have been associated with obesity prevention and in other conditions such as chronic diarrhea, hypersensitivity, irritable bowel syndrome, Helicobacter pylori infection, lactose intolerance, and gastroenteritis which all are intimately linked with an unhealthy way of life. A malfunctioning inflammatory response may affect the intestinal epithelial barrier’s ability to function by interfering with the normal metabolic processes. In this regard, several studies have shown that fermented dairy probiotics products improve human health by stimulating the growth of good bacteria in the gut at the same time increasing the production of metabolic byproducts. The fermented functional food matrix around probiotic bacteria plays an important role in the survival of these strains by buffering and protecting them from intestinal conditions such as low pH, bile acids, and other harsh conditions. On average, cultured dairy products included higher concentrations of lactic acid bacteria, with some products having as much as 109/mL or g. The focus of this review is on fermented dairy foods and associated probiotic products and their mechanisms of action, including their impact on microbiota and regulation of the immune system. First, we discussed whey and whey-based fermented products, as well as the organisms associated with them. Followed by the role of probiotics, fermented-product-mediated modulation of dendritic cells, natural killer cells, neutrophils, cytokines, immunoglobulins, and reinforcement of gut barrier functions through tight junction. In turn, providing the ample evidence that supports their benefits for gastrointestinal health and related disorders.

Dietary intake of probiotic fermented milk benefits the gut and reproductive health in mice fed with an obesogenic diet

Probiotics have been suggested as alternatives to pharmacological drugs in the treatment of a variety of medical problems, including obesity management, which is often linked to low sperm production. Also, probiotic fermented products are known to boost host immune response, immunosenescence, infection tolerance, and redox homeostasis, but their direct role in male fertility has been less investigated. This study assessed the effect of two probiotic strains, L. fermentum NCDC 400 and L. rhamnosus NCDC 610, and fructooligosaccharide (FOS) fermented milk supplementation. We identified the significantly reduced oxidative stress markers in the plasma and liver of HF diet-fed animals. We determined the role of key testicular enzymes of steroidogenic pathway genes StAR, P450scc, and 17βHSD in maintaining the testosterone concentration and restoring testicular structures. In conclusion, the present work illustrated the ability of both probiotics L. fermentum NCDC 400 and L. rhamnosus NCDC 610 as regulatory agents with beneficial effects on weight loss and endogenous testosterone with substantially improved sperm motility in male diet-induced obesity (DIO) models. Our findings indicate that fermented milk supplementation may be an alternative treatment for preventing obesity and other related metabolic syndromes.

Genome Sequence of Lacticaseibacillus rhamnosus Strain NCDC610, Isolated from a Traditional Cereal-Based Fermented Milk Product (Raabadi)

We announce the draft genome sequence of Lacticaseibacillus rhamnosus NCDC610, an isolate from an Indian traditional cereal-based fermented milk product (Raabadi). The genome size of Lacticaseibacillus rhamnosus NCDC610 is 2.91 Mb with the assembled sequence, and the genome consists of 67 contigs.

Comparative Genomic Analysis Determines the Functional Genes Related to Bile Salt Resistance in Lactobacillus salivarius

Lactobacillus salivarius has drawn attention because of its promising probiotic functions. Tolerance to the gastrointestinal tract condition is crucial for orally administrated probiotics to exert their functions. However, previous studies of L. salivarius have only focused on the bile salt resistance of particular strains, without uncovering the common molecular mechanisms of this species. Therefore, in this study, we expanded our research to 90 L. salivarius strains to explore their common functional genes for bile salt resistance. First, the survival rates of the 90 L. salivarius strains in 0.3% bile salt solutions were determined. Comparative genomics analysis was then performed to screen for the potential functional genes related to bile salt tolerance. Next, real-time polymerase chain reaction and gene knockout experiments were conducted to further verify the tolerance-related functional genes. The results indicated that the strain-dependent bile salt tolerance of L. salivarius was mainly associated with four peptidoglycan synthesis-related genes, seven phosphotransferase system-related genes, and one chaperone-encoding gene involved in the stress response. Among them, the GATase1-encoding gene showed the most significant association with bile salt tolerance. In addition, four genes related to DNA damage repair and substance transport were redundant in the strains with high bile salt tolerance. Besides, cluster analysis showed that bile salt hydrolases did not contribute to the bile salt tolerance of L. salivarius. In this study, we determined the global regulatory genes, including LSL_1568, LSL_1716 and LSL_1709, for bile salt tolerance in L. salivarius and provided a potential method for the rapid screening of bile salt-tolerant L. salivarius strains, based on PCR amplification of functional genes.

Insights into 6S RNA in lactic acid bacteria (LAB)

BACKGROUND

6S RNA is a regulator of cellular transcription that tunes the metabolism of cells. This small non-coding RNA is found in nearly all bacteria and among the most abundant transcripts. Lactic acid bacteria (LAB) constitute a group of microorganisms with strong biotechnological relevance, often exploited as starter cultures for industrial products through fermentation. Some strains are used as probiotics while others represent potential pathogens. Occasional reports of 6S RNA within this group already indicate striking metabolic implications. A conceivable idea is that LAB with 6S RNA defects may metabolize nutrients faster, as inferred from studies of Echerichia coli. This may accelerate fermentation processes with the potential to reduce production costs. Similarly, elevated levels of secondary metabolites might be produced. Evidence for this possibility comes from preliminary findings regarding the production of surfactin in Bacillus subtilis, which has functions similar to those of bacteriocins. The prerequisite for its potential biotechnological utility is a general characterization of 6S RNA in LAB.

RESULTS

We provide a genomic annotation of 6S RNA throughout the Lactobacillales order. It laid the foundation for a bioinformatic characterization of common 6S RNA features. This covers secondary structures, synteny, phylogeny, and product RNA start sites. The canonical 6S RNA structure is formed by a central bulge flanked by helical arms and a template site for product RNA synthesis. 6S RNA exhibits strong syntenic conservation. It is usually flanked by the replication-associated recombination protein A and the universal stress protein A. A catabolite responsive element was identified in over a third of all 6S RNA genes. It is known to modulate gene expression based on the available carbon sources. The presence of antisense transcripts could not be verified as a general trait of LAB 6S RNAs.

CONCLUSIONS

Despite a large number of species and the heterogeneity of LAB, the stress regulator 6S RNA is well-conserved both from a structural as well as a syntenic perspective. This is the first approach to describe 6S RNAs and short 6S RNA-derived transcripts beyond a single species, spanning a large taxonomic group covering multiple families. It yields universal insights into this regulator and complements the findings derived from other bacterial model organisms.

In-situ monitoring of xenobiotics using genetically engineered whole-cell-based microbial biosensors: recent advances and outlook

Industrialisation, directly or indirectly, exposes humans to various xenobiotics. The increased magnitude of chemical pesticides and toxic heavy metals in the environment, as well as their intrusion into the food chain, seriously threatens human health. Therefore, the surveillance of xenobiotics is crucial for social safety and security. Online investigation by traditional methods is not sufficient for the detection and identification of such compounds because of the high costs and their complexity. Advancement in the field of genetic engineering provides a potential opportunity to use genetically modified microorganisms. In this regard, whole-cell-based microbial biosensors (WCBMB) represent an essential tool that couples genetically engineered organisms with an operator/promoter derived from a heavy metal-resistant operon combined with a regulatory protein in the gene circuit. The plasmid controls the expression of the reporter gene, such as gfp, luc, lux and lacZ, to an inducible gene promoter and has been widely applied to assay toxicity and bioavailability. This review summarises the recent trends in the development and application of microbial biosensors and the use of mobile genes for biomedical and environmental safety concerns.

Transcriptome analysis of Cyclocarya paliurus flavonoids regulation of differently expressed genes in Enterococcus faecalis under low pH stress

Enterococcus faecalis (E. faecalis) is an indigenous intestinal bacterium and has potential to be applied as probiotic supplement. Low pH is one of the main stresses that E. faecalis has to deal with to colonize in the gastrointestinal tract. Previous study indicated low concentration of flavonoids may enhance the tolerance of probiotic to environmental stress. In the present research, transcriptome analysis was employed to investigate the influence of Cyclocarya paliurus flavonoids (CPF) on E. faecalis exposed to low pH environment. The results revealed that under the stress of low pH, genes related to cell wall and membrane, transmembrane transport, metabolism process, energy production, and conversion stress proteins were significantly differentially expressed. And certain undesired changes of which (such as genes for MFS transporter were downregulated) could be partially mitigated by CPF intervention, indicating their capacity to improve the low pH tolerance of E. faecalis. Results from this study deepened our understanding of the beneficial role of CPF on the probiotic in the gastrointestinal environment.

Combined transcriptomic and proteomic analysis of the response to bile stress in a centenarian-originated probiotic Lactobacillus salivarius Ren

Tolerance to bile stress is a crucial property for probiotics to survive in the gastrointestinal tract and exert their beneficial effects. In this work, transcriptomic analysis combined with two-dimensional electrophoresis revealed that the transcript levels of 129 genes and the abundance of 34 proteins were significantly changed in Lactobacillus salivarius Ren when exposed to 0.75 g/L ox-bile. Notably, carbohydrate metabolism shifted to the utilization of maltose and glycerol for energy production, suggesting that L. salivarius Ren expanded carbon sources profile for gut adaptation in response to bile. Moreover, the enzymes involved in cell surface charge modification and the cell envelope-located hemolysin-like protein were overproduced, which was supposed to hinder the penetration of bile. Then, the up-regulated ABC transporters could contribute to the extrusion of bile accumulated in the cytoplasm. Additionally, proteolytic system was activated to provide more amino acids for the synthesis and repair of proteins damaged by bile. Finally, γ-glutamylcysteine with antioxidant activity and oxidoreductases for redox homeostasis were increased to cope with the bile-induced oxidative stress. These findings provide new insights into the molecular mechanisms involved in bile stress response and adaptation in L. salivarius.

Proteomics fingerprints of systemic mechanisms of adaptation to bile in Lactobacillus fermentum

Lactobacillus fermentum is a natural resident of the human GIT and is used as a probiotic. A unique property of L. fermentum is its ability to tolerate, colonize, and survive in the harsh conditions of bile, which facilitates transient colonization of the host colon. In the current study, we investigated the key mechanisms of action involved in bacterial survival in the presence of bile, using high-resolution mass spectrometry. A total of 1071 proteins were identified, among which 378 were up-regulated and 368 down-regulated by ≥2-fold (t-test, p < .05). Differentially regulated proteins comprised both intracellular and surface-exposed (i.e., membrane) proteins (p < .01, t-test for total proteome analysis; p < .05, t-test for membrane proteome analysis). These alterations strengthen the cell envelope and also mediate bile efflux by adjusting carbohydrate metabolic pathways and prevention of protein misfolding. These processes are mainly involved in the active removal of bile salts or amelioration of its adverse effects on cells. Further investigation of mRNA transcript expression levels of selected proteins by quantitative reverse transcriptase-PCR verified the proteomic data. Together, our proteomics findings reveal the roles of post-stress recovery proteins and highlight the interacting pathways responsible for bacterial cell tolerance to bile stress. BIOLOGICAL SIGNIFICANCE: Our intestinal tract is a nutrient-rich milieu crowded with up to 100 trillion (10¹⁴) of microbes. The fact that we are born germ-free describes that these microbes must colonize our intestinal tract from outside. However, their survival is also complicated because of hazardous conditions in the gut due to the presence of bile acid and others, which exerts a deleterious effect on the beneficial microbial load. While there was limited information available describing the comprehensive mechanism of survival? Furthermore, the imbalance of these micro floras leads to numerous disease conditions. It explains the need for enhanced understanding of host-microbe interactions in the colon. The present study majorly focuses on identifying "how microbes respond to environmental stressors" in this context, particularly bile acid response. This work addresses a fascinating cellular mechanism involved in the complex changes of bile induction in the microbial system; in this case, L. fermentum NCDC 605 a well established probiotic organism. In this article, we decipher the characteristic adaptation mechanism adjusted by probiotics in the harsh condition of 1.2% bile. The generated new knowledge will also improve the potential therapeutic efficacy of probiotics strains in clinical trials for patients of inflammatory bowel diseases (IBD) and related disorders.

Cadmium tolerance pathway in Anopheles gambiae senso stricto

Cadmium is one of the widely used heavy metals (HM) in commercial and industrial products and contributes to environmental contamination in an urban setting. In our previous studies, we established that An. gambiae sensu stricto, a vector of malaria, had adapted to HM pollutants in nature despite their proclivity for unpolluted aquatic habitats. We further demonstrated that heavy metal tolerance adaptation process impacts a biological cost to the fitness of the mosquito and potentially involves the induction of specific HM-responsive transcripts and proteins. Here we interrogated differential proteomic profiles of the cadmium tolerant vs. naïve strains of An. gambiae to shed light on proteomic processes that underpinned biological cost to fitness. We identified a total of 1067 larval proteins and observed significant down-regulation of proteins involved in larval immune responses, energy metabolism, antioxidant enzymes, protein synthesis, and proton transport. Our results suggest that mosquitoes can adjust their biological program through proteome changes to counter HM pollution. Since our study was done in controlled laboratory settings, we acknowledge this may not wholly represent the conditions HM polluted environments. Nevertheless, mosquitoes deploying this strategy have the potential of creating an urban enclave for breeding and thrive and become agents of sporadic malaria epidemics.

Recombinant purified buffalo leukemia inhibitory factor plays an inhibitory role in cell growth

Leukemia Inhibitory Factor (LIF) is a polyfunctional cytokine, involved in numerous regulatory effects in vivo and in vitro, varying from cell proliferation to differentiation, and has therapeutic potential for treating various diseases. In the current study, a COS-1 cell line overexpressing recombinant Buffalo LIF (rBuLIF) was established. The rBuLIF was purified to homogeneity from the total cell lysate of COS-1 cells using a two-step affinity chromatography. The purified LIF was confirmed by western blot and mass spectrometer (MS/MS). Particularly, high-resolution MS has identified the rBuLIF with 73% of sequence coverage with highest confidence parameters and with the search engine score of 4580. We determined the molecular weight of rBuLIF protein to be 58.99 kDa and 48.9 kDa with and without glycosylation, respectively. Moreover, the purified rBuLIF was verified to be functionally active by measuring the growth inhibition of M1 myeloid leukemia cells, revealing a maximum inhibition at 72 hours and half-maximal effective concentration (EC50) of 0.0555 ng/ml, corresponding to a specific activity of >1.6×10⁷ units/mg. Next, we evaluated the effect of rBuLIF on buffalo mammary epithelial cell lines for its role in involution and also identified the IC50 value for BuMEC migrating cells to be 77.8 ng/ml. Additionally, the treatment of MECs (BuMEC and EpH4) displayed significant (P < 0.05) reduction in growth progression, as confirmed by qRT-PCR analysis, suggesting its strong involvement in the involution of the mammary gland in vivo. Thus, we conclude that the glycosylated rBuLIF, purified from COS-1 cells was found to be functionally active as its natural counterpart.

Evaluation of some in vitro probiotic properties of Lactobacillus fermentum Strains

This study aimed to check the in vitro probiotic properties of eleven Lactobacillus fermentum strains previously isolated from fermented dairy products and infant faeces. These cultures were tested for their tolerance to different pH such as 2.0, 2.5, 3.0, 3.5 and 6.5, bile salt hydrolysis and cell surface hydrophobicity. All the strains were persistent at pH 3.5 for 3 h whereas only faecal origin isolates such as L. fermentum BIF-19, BIF-20, BIF-18 and MTCC 8711 had shown considerable growth at pH 2.5. The strains NCDC-400, MTCC 8711, BIF-18, BIF-19 and BIF-20 showed slight to intense precipitation zone of bile salt hydrolase activity by agar plate assay. The strain L. fermentum BIF-19 exhibited best preliminary probiotic properties was selected for the adhesion to Caco-2 cell lines, which shows similar adhesion to that observed for standard probiotic Lactobacillus rhamnosus GG.

Draft Genome Sequence of Lactobacillus fermentum NCDC 400, Isolated from a Traditional Indian Dairy Product

We announce here the draft genome sequence of Lactobacillus fermentum NCDC 400, a potential probiotic strain isolated from a traditional Indian dairy product. The genome size of Lactobacillus fermentum NCDC 400 is 1.89 Mb, and the assembled sequence consists of 185 contigs joined into 138 scaffolds.