To overcome the economic losses associated with fungi and their toxic metabolites, environmentally safe and efficient approaches are needed. To this end, biological control using yeasts and safe bacterial strains and their products are being explored to replace synthetic fungicides. In the present study, the biocontrol effect of a yeast strain of Kluyveromyces marxianus , QKM-4, against the growth and mycotoxin synthesis potential of key toxigenic fungi was evaluated. In vitro assays were performed to find the application of yeast volatile organic compounds (VOCs) against fungal contamination on important agricultural commodities. The removal of ochratoxin A (OTA) and deoxynivalenol (DON) by living and heat-inactivated yeast cells was also explored. VOCs produced by strain QKM-4 were able to significantly limit the fungal growth of 17 fungal species belonging to genera Aspergillus , Penicillium , and Fusarium . Yeast VOCs were able to reduce OTA biosynthesis potential of Penicillium verrucosum and Aspergillus carbonarius by 99.6 and 98.7%, respectively. In vivo application of QKM-4 VOCs against Fusarium oxysporum and A. carbonarius infection on tomatoes and grapes, respectively, determined a complete inhibition of fungal spore germination. GC/MS-based analysis of yeast VOCs identified long-chain alkanes, including nonadecane, eicosane, docosane, heptacosane, hexatriacontane, and tetracosane. In vitro testing of the mycotoxin-binding potential of the living and heat-inactivated QKM-4 cells showed a reduction of OTA and DON up to 58 and 49%, respectively, from artificially contaminated buffers. Our findings clearly demonstrate the strong antifungal potential of K. marxianus QKM-4 and propose this strain as a strong candidate for application in agriculture to safeguard food and feed products.

Gut microbiota plays a major role in regulating the host metabolism and immune system. However, the structure of microbiome population is altered constantly by diverse factors including diet and environment. In particular, the gut microbiome dynamics is influenced by diet composition and their associated metabolites. Many studies in the recent past reported on diet induced dysbiosis in the gut microbiome, the modulating ratio between Firmicutes and Bacteroidetes plays a central role in maintaining the microbiome diversity in the gut and their abundance regulates obese conditions. Although there are several reports on gut microbial dysbiosis (Firmicutes/Bacteroidetes) at phylum level but only few of them highlight at the genera level. In the present study, we focused more on the impact of cafeteria diet (CAF) with respect to the gut microbiome richness at the genera level in SD rats. Three weeks old Sprague Dawley (SD) rats were fed with normal chow diet and cafeteria diet (CAF). After 10 weeks, serum, tissue samples (small intestine and cecum), cecum fecal and fecal pellet were collected. Biochemical analysis from serum, Gene expression analysis of pro-inflammatory markers from tissues and microbiome analysis from fecal samples were analysed. CAF diet fed rat in the present study developed obesity with increased body weight, few of them developed the resistance to weight gain (WGR) and these animal shows significantly increased abundance of Bacteriodetes-Prevotella compared to obese animals. This study suggests that detailed research needed to address the contribution of microbiota abundance at the genera level. We further explored the influence of diet induced microbiota changes on immune response; increase in Bacteroidetes leads to increased LPS and this in turn elicit immune reaction in the gut. Moreover, variation in gut microbiota also af-How to cite this paper: Alasmar, R.M., 776Advances in Microbiology fects the gut barrier function (Tight junction proteins) and increase metabolic endotoxemia that leads to activation of innate immune system and low-grade inflammation. Further studies on these lines targeting the microbiota changes in the gut at the genera level is warranted to gain more knowledge.

Mycotoxins, the secondary fungal metabolites are important contaminants of food and feed. Among the other contaminants, aflatoxin B1 (AFB1) and OTA are frequently detected in the animal feed product. In the present study, the mixed dairy cow feed products were collected from the supermarkets in Qatar and analyzed for the presence of AFB1 and OTA. Yeast strains were isolated and tested for their biological control activities against aflatoxigenic and ochratoxin fungi. We demonstrated that local 15 yeasts isolates have important antifungal potential activities through the synthesis of volatile organic compounds (VOC) that are able to act against the mycotoxigenic fungi and their synthesis of the mycotoxins. Two Yeast strains (4&2) isolated from fermented food, have shown a great antifungal inhibition growth in-vitro as well as spores inhibition and mycotoxins synthesis.

Microbiome now is considered as an organ within our system to regulate metabolism, cellular immune response and eventually maintain the health. Gut microbiota has been studied extensively in the recent past due to the possibility of high-resolution analysis by next-generation sequencing technology. As the gut microbiota, is essential for the host development and physiological function, a gut microbial community dominated by Firmicutes and Bacteroidetes and their relative abundance and dysbiosis influences obese conditions and various disease progression. The microbiota dysbiosis in the gut contributed mainly by diet as a carbon economy of the colon apart from genetic and environmental variations. Postgenomic era reveals the paradigm of the gut-brain axis and association of gut microbial metabolites such as short chain fatty acids (SCFA) and disease progression of inflammatory bowel disorder (IBD) and colon cancer. In addition, the landscape of gut microbiome is influenced by other factors such as pregnancy, smoking, alcohol consumption and stress. The functional consequence of gut microbial dysbiosis towards disease progression and understanding their mechanism in terms of the immune response through studies on rodent animal models also are discussed in this review.

Scope: The composition of the gut microbiota is influenced by the dietary nutrient. Sugar has been linked with many metabolic health disorders such as heart disease, metabolic syndrome, and immune disorders. Long-term consumption of sugar influences the landscape of gut microbiota by altering the gut microbial population called dysbiosis. This study aims to evaluate the impact of long-term consumption of high sugar diet (HSD) on the diversity of gut microbiota. Methods and results: CD1 mice are given high concentration of sugar for 15 weeks followed by a recovery period of 10 weeks. Real-time polymerase chain reaction and 16S rRNA next-generation sequencing methods employ to identify microbiome diversity. The results show that Firmicutes and Bacteroidetes are the predominant phyla in control, cecum, and fecal samples. Firmicutes population are gradually increased in treated samples even after the recovery period, whereas Bacteroidetes abundance slightly reduces throughout the study. Conclusion: The present study shows that the impact of long period of high sugar diet consumption alters the diversity of normal gut flora which can be restored after 10 weeks of sugar withdrawal. This indicates that the intervention of healthy and nutritious diet influences gut microbes and this can be beneficial in reducing the implication of early life metabolic disorders such as obesity.

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Teucrium polium (germander, Lamiaceae) is a local plant in Qatar that has been used in folk medicine to treat numerous illnesses. It is known for its antioxidant, analgesic, anticancer, and antibacterial activities. This study aimed to evaluate the anti-inflammatory activity of Teucrium polium (TP) extract by α-carrageen-induced paw edema in adult Sprague Dawley rats. The animals were randomly grouped into control, acute inflammation, and plant extract groups. Acute inflammation was induced by a sub-plantar injection of 100 µL of 1% α-carrageenan into the rat’s right hind paw. Three different doses of the ethanolic extract of TP were tested at different time periods (1, 3, and 5 hours). All doses of the TP ethanolic extract showed significant inhibition of α-carrageenan-induced rat paw edema in a dose-dependent manner in both early and late phases of edema formation. The size of the α-carrageen induced paw edema was significantly reduced one, three, and five hours after TP extract injection compared to the acute inflammation group. This inhibition was accompanied by high expression of interleukin 10 (IL-10) and low expression of monocyte chemoattractant protein 1 (MCP-1), IL-1β and tumor necrosis factor alpha (TNF-α). The results indicated that the ethanolic extracts of TP possess significant anti-inflammatory and potential pharmaceutical properties.