Exiguobacterium sp. is endowed with antibiotic properties against Gram positive and negative bacteria

Interaction of Acinetobacter sp. RIT 592 induces the production of broad-spectrum antibiotics in Exiguobacterium sp. RIT 594

Antimicrobial resistance (AMR) is one of the most alarming global public health challenges of the 21st century. Over 3 million antimicrobial-resistant infections occur in the United States annually, with nearly 50,000 cases being fatal. Innovations in drug discovery methods and platforms are crucial to identify novel antibiotics to combat AMR. We present the isolation and characterization of potentially novel antibiotic lead compounds produced by the cross-feeding of two rhizosphere bacteria, Acinetobacter sp. RIT 592 and Exiguobacterium sp. RIT 594. We used solid-phase extraction (SPE) followed by liquid chromatography (LC) to enrich antibiotic extracts and subsequently mass spectrometry (MS) analysis of collected fractions for compound structure identification and characterization. The MS data were processed through the Global Natural Product Social Molecular Networking (GNPS) database. The supernatant from RIT 592 induced RIT 594 to produce a cocktail of antimicrobial compounds active against Gram-positive and negative bacteria. The GNPS analysis indicated compounds with known antimicrobial activity in the bioactive samples, including oligopeptides and their derivatives. This work emphasizes the utility of microbial community-based platforms to discover novel clinically relevant secondary metabolites. Future work includes further structural characterization and antibiotic activity evaluation of the individual compounds against pathogenic multidrug-resistant (MDR) bacteria.

Diving into freshwater microbial metabolites: Pioneering research and future prospects

In practically every facet of life, especially nutrition, agriculture, and healthcare, microorganisms offer a prospective origin for abundant natural substances and products. Among these microorganisms, bacteria also possess the capability to rapidly acclimate to diverse environments, utilize varied resources, and effectively respond to environmental fluctuations, including those influenced by human activities like pollution and climate change. The ever-changing environment of freshwater bodies influences bacterial communities, offering opportunities for improving health and environmental conservation that remain unexplored. Herein, the study discusses the bacterial taxa along with specialised metabolites with antioxidant, antibacterial, and anticancer activity that have been identified from freshwater environments, thus achieving Sustainable Development Goals addressing health and wellbeing (SDG-3), economic growth (SDG-8) along with industrial development (SDG-9). The present review is intended as a compendium for research teams working in the fields of medicinal chemistry, organic chemistry, clinical research, and natural product chemistry.

Metabolic Profiling, Antiviral Activity and the Microbiome of Some Mauritian Soft Corals

Soft corals, recognized as sessile marine invertebrates, rely mainly on chemical, rather than physical defense, by secreting intricate secondary metabolites with plausible pharmaceutical implication. Their ecological niche encompasses a diverse community of symbiotic microorganisms which potentially contribute to the biosynthesis of these bioactive metabolites. The emergence of new viruses and heightened viral resistance underscores the urgency to explore novel pharmacological reservoirs. Thus, marine organisms, notably soft corals and their symbionts, have drawn substantial attention. In this study, the chemical composition of four Mauritian soft corals: Sinularia polydactya, Cespitularia simplex, Lobophytum patulum, and Lobophytum crassum was investigated using LC-MS techniques. Concurrently, Illumina 16S metagenomic sequencing was used to identify the associated bacterial communities in the named soft corals. The presence of unique biologically important compounds and vast microbial communities found therein was further followed up to assess their antiviral effects against SARS-CoV-2 and HPV pseudovirus infection. Strikingly, among the studied soft corals, L. patulum displayed an expansive repertoire of unique metabolites alongside a heightened bacterial consort. Moreover, L. patulum extracts exerted some promising antiviral activity against SARS-CoV-2 and HPV pseudovirus infection, and our findings suggest that L. patulum may have the potential to serve as a therapeutic agent in the prevention of infectious diseases, thereby warranting further investigation.

Chromatographic isolation of potentially novel antibiotic compounds produced by Yimella sp. RIT 621

OBJECTIVE

Antibiotic resistant infections have become a global health crisis causing 1.2 million deaths worldwide in 2019 [1]. In a previous study, we identified a bacterium from a rare genus, Yimella, and found in an initial antibiotic screening that they produce broad-spectrum bactericidal compounds [2]. Herein, we focus on the characterization of these potential novel antimicrobial compounds produced by Yimella sp. RIT 621.

RESULTS

We used solid-phase extraction and C18 reverse-phase chromatography to isolate the antibiotic-active compounds found in organic extracts from liquid cultures of Yimella sp. RIT 621. We tracked the antimicrobial activity by testing the extracts in disc diffusion inhibitory assays and observed its increase after each purification stage.

Valorization of biowastes as fermentative substrate for production of Exiguobacterium sp. GM010 pigment and toxicity effect in rats

Bioconversion of biowastes chicken feather (CF), prawn carapace (PC), fish scale (FS), and corncob (CC) were used for Exiguobacterium sp. GM010 pigment production to reduce environmental pollution. Maximum pigment was produced in 4 % PC hydrolysate medium at pH 8 and 30 °C (0.831 Absorption Unit-AUmL^-1) compared to other hydrolysate. Biomass (1061.19 ± 26.14 mg/100 mL) and pigment yield (34.26 ± 0.62 mg/100 mL) were higher in PC medium. In CF + PC hydrolysate combination, biomass and pigment yield was 890.58 ± 11.5 mg/100 mL and 13.94 ± 0.17 mg/100 mL, respectively. Carbon and nitrogen ratio in the medium influenced pigment production. The UV-visible spectrum showed absorption peak at 357, 466, and 491 nm. Further hue angle (77-72) and chroma values (8.68-11.38) distributed over yellowish-orange region of CIELAB spectrum indicated carotenoid like characteristics. Wistar rats fed with pigment (2000 mg/kg bw) did not show sign of toxicity in haematological, biochemical and histopathological analysis. Therefore, pigment produced by recycling the biowastes promotes sustainable bioprocess and circular bioeconomy.

Draft Genome Sequences of Three Antibiotic-Producing Soil Bacteria, Staphylococcus pasteuri WAM01, Peribacillus butanolivorans WAM04, and Micrococcus yunnanensis WAM06, with Growth-Inhibiting Effects against Commensal Neisseria Strains

We report the isolation, identification, and assemblies of three antibiotic-producing soil bacteria ( Staphylococcus pasteuri , Peribacillus butanolivorans , and Micrococcus yunnanensis ) that inhibit the growth of Neisseria commensals in coculture. With pathogenic Neisseria strains becoming increasingly resistant to antibiotics, bioprospecting for novel antimicrobials using commensal relatives may facilitate discovery of clinically useful drugs.

Comparative Analysis of Microbial Community Diversity and Dynamics on Diseased Tubers During Potato Storage in Different Regions of Qinghai China

Effective storage of potatoes is very important for the food industry. Given the problems involving rotten potatoes and low quality during storage, harvested potatoes from the main potato-producing areas in the Qinghai Plateau were treated by selection and air drying (Group "A") and the others were stored directly as controls (Group "C"). Then, the microbial community structure and diversity of diseased potato tubers from four main production areas were analyzed by high-throughput sequencing technology in different storage stages. The results showed that the community composition and diversity of microbes in different regions and storage periods were different, and the dominant fungi in diseased potato tubers were Boeremia in Huangyuan (HY), Maying (MY) and Zhongling (ZL) and Apiotrichum in Huangzhong (HZ) at the genus level. The dominant bacterial genus was Pseudomonas, but its abundance varied in samples from different regions and storage periods. In the analysis of indicator species, there were some common species and endemic species in each region and period, and the period with the largest number of different species was the third period. Among the four storage periods, the region with the largest number of different species was HZ. Some fungi, especially Fusarium and other potato pathogens, were more abundant in control Group "C" than in treatment Group "A." In the diversity analysis, the α diversity of fungi in Group "C" was higher than that in Group "A," but the α diversity of bacteria in Group "A" was higher than that in Group "C," and there was no obvious regularity with storage time. The β diversity varied significantly among different regions. In addition, through functional prediction analysis, it was found that a plant pathogen was one of the main nutritional types of fungi, which indicated that treatment by selection and drying could significantly reduce phytopathogenic microbe and other microorganisms and could be used as an effective measure for potato storage compared with the prevention and control by drugs that can cause environmental pollution. Further analysis of co-occurrence network showed that pathogenic fungi Fusarium was negatively correlated with pathogenic bacteria Erwinia, and there is also a negative correlation between pathogens and antagonistic microorganisms indicated that there were various symbiotic relationships among microorganisms in diseased potatoes. This study may provide a theoretical basis for biological control of potato cellar diseases and the maintenance of potato quality during long-term storage.