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The type VI secretion system (T6SS) is a powerful bacterial molecular weapon that can inject effector proteins into prokaryotic or eukaryotic cells, thereby participating in the competition between bacteria and improving bacterial environmental adaptability. Although most current studies of the T6SS have focused on animal bacteria, this system is also significant for the adaptation of plant-associated bacteria. This paper briefly introduces the structure and biological functions of the T6SS. We summarize the role of plant-associated bacterial T6SS in adaptability to host plants and the external environment, including resistance to biotic stresses such as host defenses and competition from other bacteria. We review the role of the T6SS in response to abiotic factors such as acid stress, oxidation stress, and osmotic stress. This review provides an important reference for exploring the functions of the T6SS in plant-associated bacteria. In addition, characterizing these anti-stress functions of the T6SS may provide new pathways toward eliminating plant pathogens and controlling agricultural losses. [ABSTRACT FROM AUTHOR]

Lakes are particularly vulnerable to environmental changes and thus considered sentinels and integrators of processes that occur in the atmosphere and terrestrial environments. Individual up to ecosystemic metabolic pathways and nutrient cycling in lakes respond to both natural and human disturbances. Disentangling the effect of such different forces is a particular challenge for lake ecological studies. Here we present a conference paper based on previous studies carried out in Andean-Patagonian lakes under two important events: the Puyehue–Cordón Caulle eruption in 2011 and the glacial recession with a glacial lake outburst flood (GLOF) in 2009. We discuss how biological variables responded to these two natural events that produced the input of minerogenic inorganic particles into the lakes. We present the combination of observational and experimental research, including new molecular methods, that contributed to understanding the effects of these inorganic particles on aquatic ecosystems. Both events involved changes in the transparency of the lakes that affected phytoplankton parameters (biomass vertical distribution), bacteria composition and community structuring process. Finally, both events had very contrasting effects on zooplankton, in the same range of particle concentrations. Particles from glacial melting are beneficial for daphnids reducing the impact of ultraviolet radiation and increasing the quality of the food. In contrast, volcanic ashes are abrasive materials that have a deleterious effect for filtering zooplankton. [ABSTRACT FROM AUTHOR]

Ticks are ectoparasites responsible for the transmission of various pathogens to vertebrates. They represent one of the major threats to livestock production worldwide due to their impact on the health, production and welfare of livestock destined for human consumption. The development of resistance to the main families of ixodicides used for their control has led to the search for new alternatives, where microbial control is an option. The use of microbial control agents against the tick Rhipicephalus microplus is reviewed in this paper. Bacteria such as Bacillus thuringiensis, Serratia marcescens and Staphylococcus spp. the nematodes Steinernema spp. and Heterorhabditis spp. as well as the fungi Metarhizium anisopliae and Beauveria bassiana are the most studied organisms for use as biological control agents against ticks. Laboratory, stable and field trials with free-living and parasitised ticks have shown that microbial agents can control both susceptible and ixodicide-resistant tick populations. However, multidisciplinary studies using novel tools like genomics, transcriptomics and proteomics should be carried out to understand the virulence factors which microbial agents use to induce pathogenesis and virulence in ticks. In addition, applied research will be carried out with the aim of improving techniques for large-scale application, as well as the improvement of cultivation, storage, formulation and application methods. [ABSTRACT FROM AUTHOR]

The vast majority of cultural heritage objects consist of materials that can be subjected to biodeterioration. Currently, there is significant number of publications showing which materials are capable of destroying certain organisms, and what conservation and restoration procedures are required. However, there is neither a clear classification of these diverse events nor their visual representation. In our review, for the first time, an attempt is made to compare the type of biodeterioration, based on the destruction of a particular material, with a specific color of the rainbow. In this regard, a cultural heritage objects made of a single material are designated as one color icon; and those made of composite materials are designated as pictogram consisting of several icons of corresponding colors. For example, a stone sculpture, in accordance with the rainbow code, is assigned a gray color, which was introduced to visualize stone materials. The drum corresponds to a pictogram consisting of violet (corresponds to leather) and brown (corresponds to wood). A work of easel painting on canvas corresponds to a pictogram consisting of a red color icon (corresponds to canvas) and a gold color icon (corresponds to painting materials). We used cold color shades to denote basic inorganic materials, and cold color shades to denote organic materials. The proposed rainbow code for biodetermination is an open platform that can be expanded by adding new colors for new materials introduced, and allows to translate potentially any cultural heritage object into a pictogram with colors that correspond to the materials used in its manufacture. Such a graphical interpretation can help both systematize the storage conditions of museum exhibits and facilitate understanding of the processes of biodeterioration of composite materials. [ABSTRACT FROM AUTHOR]

Currently, there are many different therapies available for inflammatory bowel disease (IBD), including engineered live bacterial therapeutics. However, most of these studies focus on producing a single therapeutic drug using individual bacteria, which may cause inefficacy. The use of dual drugs can enhance therapeutic effects. However, expressing multiple therapeutic drugs in one bacterial chassis increases the burden on the bacterium and hinders good secretion and expression. Therefore, a dual-bacterial, dual-drug expression system allows for the introduction of two probiotic chassis and enhances both therapeutic and probiotic effects. In this study, we constructed a dual bacterial system to simultaneously neutralize pro-inflammatory factors and enhance the anti-inflammatory pathway. These bacteria for therapy consist of Escherichia coli Nissle 1917 that expressed and secreted anti-TNF-α nanobody and IL-10, respectively. The oral administration of genetically engineered bacteria led to a decrease in inflammatory cell infiltration in colon and a reduction in the levels of pro-inflammatory cytokines. Additionally, the administration of engineered bacteria did not markedly aggravate gut fibrosis and had a moderating effect on intestinal microbes. This system proposes a dual-engineered bacterial drug combination treatment therapy for inflammatory bowel disease, which provides a new approach to intervene and treat IBD. Key points: • The paper discusses the effects of using dual engineered bacteria on IBD • Prospects of engineered bacteria in the clinical treatment of IBD [ABSTRACT FROM AUTHOR]

The paper deals with the fossil cyanobacterial films from the Lower Proterozoic (Livvian) shungite in Karelia, Russia. The films were previously described as a formal species Cyathotes nigoserica Makarikhin. They were formed by bacteria and possibly by fungi, which inhabited the littoral or supralittoral (the tidal zone). These organisms were adapted to the existence in temporally (possibly, long-lasting) dry conditions, which is proved by the development of dense coatings protecting their bodies from dehydration. This basically bacterial community influenced intensely the mineral substrate, changed its structure, and enriched it with biogenic constituents, thus forming an archaic soil microprofile. The research revealed the following signs of ancient soil formation: surface transformation of the mineral substrate texture by the vital activity of terrestrial organisms (bacteria, fungi) with the formation of a specific cellular topographic pattern,; changes in the internal structure of the substrate and the appearance of wedge-shaped fracture casts in the underlying matrix; redistribution of inorganic compounds during the formation of a paleosurface microprofile (the increasing content of silicon oxide in the upper part with a simultaneous reduction in the amount of iron oxides). [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are genotoxic, carcinogenic, and persistent in the environment and are therefore of great concern in the environmental protection field. Due to the inherent recalcitrance, persistence and nonreactivity of PAHs, they are difficult to remediate via traditional water treatment methods. In recent years, microbial remediation has been widely used as an economical and environmentally friendly degradation technology for the treatment of PAH-contaminated water. Various bacterial and microalgal strains are capable of potentially degrading or transforming PAHs through intrinsic metabolic pathways. However, their biodegradation potential is limited by the cytotoxic effects of petroleum hydrocarbons, unfavourable environmental conditions, and biometabolic limitations. To address this limitation, microbial communities, biochemical pathways, enzyme systems, gene organization, and genetic regulation related to PAH degradation have been intensively investigated. The advantages of algal–bacterial cocultivation have been explored, and the limitations of PAHs degradation by monocultures of algae or bacteria have been overcome by algal–bacterial interactions. Therefore, a new model consisting of a “microalgal–bacterial consortium” is becoming a new management strategy for the effective degradation and removal of PAHs. This review first describes PAH pollution control technologies (physical remediation, chemical remediation, bioremediation, etc.) and proposes an algal–bacterial symbiotic system for the degradation of PAHs by analysing the advantages, disadvantages, and PAH degradation performance in this system to fill existing research gaps. Additionally, an algal–bacterial system is systematically developed, and the effects of environmental conditions are explored to optimize the degradation process and improve its technical feasibility. The aim of this paper is to provide readers with an effective green and sustainable remediation technology for removing PAHs from aquatic environments. [ABSTRACT FROM AUTHOR]

Nowadays, emerging pollutants are widely used and exist in wastewater, such as antibiotics, heavy metals, nanoparticle and microplastic. As a green alternative for wastewater treatment, microalgal-bacterial symbiosis has been aware of owning multiple merits of low energy consumption and little greenhouse gas emission. Thus, the responses of microalgal-bacterial symbiosis to emerging pollutants in wastewater treatment have become a hotspot in recent years. In this review paper, the removal performance of microalgal-bacterial symbiosis on organics, nitrogen and phosphorus in wastewater containing emerging pollutants has been summarized. The adaptation mechanisms of microalgal-bacterial symbiosis to emerging pollutants have been analyzed. It is found that antibiotics usually have hormesis effects on microalgal-bacterial symbiosis, and that microalgal-bacterial symbiosis appears to show more capacity to remove tetracycline and sulfamethoxazole, rather than oxytetracycline and enrofloxacin. Generally, microalgal-bacterial symbiosis can adapt to heavy metals at a concentration of less than 1 mg/L, but its capabilities to remove contaminants can be significantly affected at 10 mg/L heavy metals. Further research should focus on the influence of mixed emerging pollutants on microalgal-bacterial symbiosis, and the feasibility of using selected emerging pollutants (e.g., antibiotics) as a carbon source for microalgal-bacterial symbiosis should also be explored. This review is expected to deepen our understandings on emerging pollutants removal from wastewater by microalgal-bacterial symbiosis. [ABSTRACT FROM AUTHOR]

Continuous directed evolution of base editors (BEs) has been successful in bacteria cells, but not yet in mammalian cells. Here, we report the development of a Continuous Directed Evolution system in Mammalian cells (CDEM). CDEM enables the BE evolution in a full-length manner with Cas9 nickase. We harness CDEM to evolve the deaminases of cytosine base editor BE3 and adenine base editors, ABEmax and ABE8e. The evolved cytidine deaminase variants on BE4 architecture show not only narrowed editing windows, but also higher editing purity and low off-target activity without a trade-off in on-targeting activity. The evolved ABEmax and ABE8e variants exhibit narrowed or shifted editing windows to different extents, and lower off-target effects. The results illustrate that CDEM is a simple but powerful approach to continuously evolve BEs without size restriction in the mammalian environment, which is advantageous over continuous directed evolution system in bacteria cells. Continuous directed evolution of base editors (BEs) has been successful in bacteria cells, but not yet in mammalian cells. Here, the authors report a Continuous Directed Evolution system in Mammalian cells (CDEM) enabling the BE evolution in a full-length manner with Cas9 nickase. [ABSTRACT FROM AUTHOR]

Aquilaria sinensis is a significant resin-producing plant worldwide that is crucial for agarwood production. Agarwood has different qualities depending on the method with which it is formed, and the microbial community structures that are present during these methods are also diverse. Furthermore, the microbial communities of plants play crucial roles in determining their health and productivity. While previous studies have investigated the impact of microorganisms on agarwood formation, they lack comprehensiveness, particularly regarding the properties of the microbial community throughout the entire process from seedling to adult to incense formation. We collected roots, stems, leaves, flowers, fruits and other tissues from seedlings, healthy plants and agarwood-producing plants to address this gap and assess the dominant bacterial species in the microbial community structures of A. sinensis at different growth stages and their impacts on growth and agarwood formation. The bacteria and fungi in these tissues were classified and counted from different perspectives. The samples were sequenced using the Illumina sequencing platform, and sequence analyses and species annotations were performed using a range of bioinformatics tools to assess the plant community compositions. An additional comparison of the samples was conducted using diversity analyses to assess their differences. This research revealed that Listeria, Kurtzmanomyces, Ascotaiwania, Acinetobacter, Sphingobium, Fonsecaea, Acrocalymma, Allorhizobium, Bacillus, Pseudomonas, Peethambara, and Debaryomyces are potentially associated with the formation of agarwood. Overall, the data provided in this article help us understand the important roles played by bacteria and fungi in the growth and agarwood formation process of A. sinensis, will support the theoretical basis for the large-scale cultivation of A. sinensis, and provide a basis for further research on microbial community applications in agarwood production and beyond. [ABSTRACT FROM AUTHOR]

The study of microorganism interactions is important for understanding the organization and functioning of microbial consortia. Additionally, the interaction between yeast and bacteria is of interest in the field of health and nutrition area for the development of probiotics. To investigate these microbial interactions at the cellular and molecular levels, a simple, reliable, and quantitative method is proposed. We demonstrated that flow cytometry enables the measurement of interactions at a single-cell level by detecting and counting yeast cells with bound fluorescent bacteria. Imaging flow cytometry revealed that the number of bacteria attached to yeast followed a Gaussian distribution whose maximum reached 14 bacterial cells using a clinical Escherichia coli strain E22 and the laboratory yeast strain BY4741. We found that the dynamics of adhesion resemble a Langmuir adsorption model, albeit it is a rapid and almost irreversible process. This adhesion is dependent on the mannose-specific type 1 fimbriae, as E. coli mutants lacking these appendages no longer adhere to yeast. However, this type 1 fimbriae-dependent adhesion could involve additional yeast cell wall factors, since the interaction between bacteria and yeast mutants with altered mannan content remained comparable to that of wild-type yeast. In summary, flow cytometry is an appropriate method for studying bacteria-yeast adhesion, as well as for the high-throughput screening of candidate molecules likely to promote or counteract this interaction. [ABSTRACT FROM AUTHOR]

Due to its nutritional value and health benefits, the date palm (Phoenix dactylifera L.) is an essential dietary food crop throughout Middle Eastern and African countries. Consumers are concerned about the possible microbial contamination of dates, especially since most dates arriving in local markets are unprocessed. The absence of processing increases the possibility of microbial contamination, which raises the probability of microbial contamination. This study aims to analyze and evaluate the variability of fungal and bacterial microbiota identified in the most popular date palm fruits in Saudi Arabia. The study assessed ten date variety fruits from the most popular date palm varieties for consumption in Saudi Arabia and analyzed the microbial count. Morphological and molecular characterization and comparison of nuclear ribosomal DNA internal transcribed spacer (ITS) sequences identified 78 fungi, including 36 distinct species across 15 fungal genera. Alternaria, Fusarium, Curvilaria, Aspergillus, and Penicillium were the most frequent genera among the ten fruit cultivars studied, according to ITS-rDNA sequence analysis. Furthermore, 36 bacterial isolates were obtained from ten date varieties studied, each with a unique colony morphology. These isolates were identified based on sequence alignment and comparison of their 16S rDNA internal spacer regions to those available in public databases. The results showed that the bacterial isolates included 15 species from five bacterial genera. The results suggested that Bacillus, Stenotrophomonas, and Brucella were the prevailing genera among the ten tested fruit varieties. Some bacterial genera, such as Brucella, Achromobacter, and Stenotrophomonas, are well-known potential human pathogens. Chaetomium globosum was also recognized as air pollution causing adverse health effects such as allergies and as the causal agent of human fungal infections among the tested date varieties; the Rashodiah type exhibited the highest fungal contamination, whereas the Sagai variety displayed the lowest fungal contamination. Conversely, the Sukkari, Barhi, and Mejdool varieties were the most contaminated with bacteria among the ten tested varieties, while the Khalas variety showed the least bacterial contamination. To the best of the authors' knowledge, this study provides the initial comprehensive account of the molecular and morphological identification of all fungal and bacterial genera associated with date palm (P. dactylifera) fruits. [ABSTRACT FROM AUTHOR]

Intensive care unit-acquired infections are complicating events in critically ill patients. In this study we analyzed the incidence, microbiological patterns, and outcome in patients with COVID-19 versus influenza in the intensive care unit (ICU). We included all adult patients treated with invasive mechanical ventilation due to (1) COVID-19 between January 2020 and March 2022, and (2) influenza between January 2015 and May 2023 at Sahlgrenska University Hospital, Sweden. Of the 480 participants included in the final analysis, 436 had COVID-19. The incidence rates of ICU-acquired infections were 31.6/1000 and 9.9/1000 ICU-days in the COVID-19 and influenza cohorts, respectively. Ventilator-associated lower respiratory tract infections were most common in both groups. In patients with COVID-19, corticosteroid treatment was associated with an increased risk of ICU-acquired infections and with higher 90-day mortality in case of infection. Furthermore, ICU-acquired infection was associated with a prolonged time in the ICU, with more difficult-to-treat gram-negative infections in late versus early ventilator-associated lower respiratory tract infections. Further research is needed to understand how the association between corticosteroid treatment and incidence and outcome of ICU-acquired infections varies across different patient categories. [ABSTRACT FROM AUTHOR]

IncX3 plasmids carrying the New Delhi metallo-β-lactamase-encoding gene, blaNDM-5, are rapidly spreading globally in both humans and animals. Given that carbapenems are listed on the WHO AWaRe watch group and are prohibited for use in animals, the drivers for the successful dissemination of Carbapenem-Resistant Enterobacterales (CRE) carrying blaNDM-5-IncX3 plasmids still remain unknown. We observe that E. coli carrying blaNDM-5-IncX3 can persist in chicken intestines either under the administration of amoxicillin, one of the largest veterinary β-lactams used in livestock, or without any antibiotic pressure. We therefore characterise the blaNDM-5-IncX3 plasmid and identify a transcription regulator, VirBR, that binds to the promoter of the regulator gene actX enhancing the transcription of Type IV secretion systems (T4SS); thereby, promoting conjugation of IncX3 plasmids, increasing pili adhesion capacity and enhancing the colonisation of blaNDM-5-IncX3 transconjugants in animal digestive tracts. Our mechanistic and in-vivo studies identify VirBR as a major factor in the successful spread of blaNDM-5-IncX3 across one-health AMR sectors. Furthermore, VirBR enhances the plasmid conjugation and T4SS expression by the presence of copper and zinc ions, thereby having profound ramifications on the use of universal animal feeds. Carbapenem-resistant Escherichia coli, carrying blaNDM-5-IncX3 plasmids, can persist in chickens either under the presence of amoxicillin or without any antibiotic. Transcriptional regulator VirBR can promote transmission of IncX3 plasmid and persistence of blaNDM-5 in zoonotic bacteria. [ABSTRACT FROM AUTHOR]

Bioethanol is a sustainable energy alternative and can contribute to global greenhouse-gas emission reductions by over 60%. Its industrial production faces various bottlenecks, including sub-optimal efficiency resulting from bacteria. Broad-spectrum removal of these contaminants results in negligible gains, suggesting that the process is shaped by ecological interactions within the microbial community. Here, we survey the microbiome across all process steps at two biorefineries, over three timepoints in a production season. Leveraging shotgun metagenomics and cultivation-based approaches, we identify beneficial bacteria and find improved outcome when yeast-to-bacteria ratios increase during fermentation. We provide a microbial gene catalogue which reveals bacteria-specific pathways associated with performance. We also show that Limosilactobacillus fermentum overgrowth lowers production, with one strain reducing yield by ~5% in laboratory fermentations, potentially due to its metabolite profile. Temperature is found to be a major driver for strain-level dynamics. Improved microbial management strategies could unlock environmental and economic gains in this US $ 60 billion industry enabling its wider adoption. Industrial bioethanol production is driven by ecological interactions within the microbial community rather than the interactions within yeast population. Here, the authors identify bacteria affecting ethanol production and reveal temperature as the major driving force for strain-level dynamics. [ABSTRACT FROM AUTHOR]

Bacteria-mediated cancer therapeutic strategies have attracted increasing interest due to their intrinsic tumor tropism. However, bacteria-based drugs face several challenges including the large size of bacteria and dense extracellular matrix, limiting their intratumoral delivery efficiency. In this study, we find that hyperbaric oxygen (HBO), a noninvasive therapeutic method, can effectively deplete the dense extracellular matrix and thus enhance the bacterial accumulation within tumors. Inspired by this finding, we modify Escherichia coli Nissle 1917 (EcN) with cypate molecules to yield EcN-cypate for photothermal therapy, which can subsequently induce immunogenic cell death (ICD). Importantly, HBO treatment significantly increases the intratumoral accumulation of EcN-cypate and facilitates the intratumoral infiltration of immune cells to realize desirable tumor eradication through photothermal therapy and ICD-induced immunotherapy. Our work provides a facile and noninvasive strategy to enhance the intratumoral delivery efficiency of natural/engineered bacteria, and may promote the clinical translation of bacteria-mediated synergistic cancer therapy. Delivering bacteria-based drug for cancer therapy is limited by their penetration into extracellular matrix (ECM). Here the authors report effective depletion of ECM with hyperbaric oxygen therapeutic strategy to enhance bacterial accumulation within tumors and to induce immunogenic cell death. [ABSTRACT FROM AUTHOR]

The emergence of bacterial species is rooted in their inherent potential for continuous evolution and adaptation to an ever-changing ecological landscape. The adaptive capacity of most species frequently resides within the repertoire of genes encoding the secreted proteome (SP), as it serves as a primary interface used to regulate survival/reproduction strategies. Here, by applying evolutionary genomics approaches to metagenomics data, we show that abundant freshwater bacteria exhibit biphasic adaptation states linked to the eco-evolutionary processes governing their genome sizes. While species with average to large genomes adhere to the dominant paradigm of evolution through niche adaptation by reducing the evolutionary pressure on their SPs (via the augmentation of functionally redundant genes that buffer mutational fitness loss) and increasing the phylogenetic distance of recombination events, most of the genome-reduced species exhibit a nonconforming state. In contrast, their SPs reflect a combination of low functional redundancy and high selection pressure, resulting in significantly higher levels of conservation and invariance. Our findings indicate that although niche adaptation is the principal mechanism driving speciation, freshwater genome-reduced bacteria often experience extended periods of adaptive stasis. Understanding the adaptive state of microbial species will lead to a better comprehension of their spatiotemporal dynamics, biogeography, and resilience to global change. Here, by applying evolutionary genomics approaches to metagenomics data of lake microbiomes, the authors reveal that freshwater species with small genomes face extended periods with their niche adaptation capabilities frozen. [ABSTRACT FROM AUTHOR]

Aquaculture is considered one of the fastest-growing food production sectors, which provides about 41% of the world's fish food. Different types of pathogens, including bacteria, viruses, amoebas, oomycetes, fungi, and ectoparasites, have emerged to cause serious fish diseases. Medicines such as antibiotics and chemicals as well as vaccines have been widely used to combat fish diseases. However, their undesirable use to treat fish in aquaculture develops drug resistance in the surrounding microbes, especially antibiotic resistance in fish-associated bacterial strains in the column water and sediment, is mostly the consequence of applying antibiotics in aquaculture. The rise of antibiotic resistance in aquaculture and multidrug-resistant pathogens in the food chain threatens public health, hampering infection treatment and compromising food safety. Addressing this challenge is vital to protect both public well-being and the aquaculture industry's future. Basic control measures for sustainable, disease-free aquaculture, including alteration of antibiotic resistance genes into other animal pathogens, have been driven by the potential development of antibiotics with respect to environmental impact and consumer safety. Anyhow, vaccination is an effective control measure that overcomes drug resistance conditions in aquaculture; even some therapeutic and prophylactic methods are being simultaneously applied for the treatment of fish diseases. Mostly, antibiotics and probiotics do not show strong effects after the development of new mutant strains and drug-resistant pathogens. Therefore, various types of vaccines have been developed to treat aquatic pathogens effectively by using advanced molecular techniques. Previous studies on fish vaccines have typically lacked comprehensive assessments of vaccine efficacy across varying environments and species, often focusing on single pathogens while neglecting the potential influence of pathogen interactions within complex aquatic ecosystems. This review focuses on advancements in technology and prospects of vaccines used in the aquaculture industries for reducing antibiotics usage. It also discussed the vaccination from traditional to modern new-generation ones including DNA, monovalent, and polyvalent vaccines. The objective is to provide an overview of aquaculture's major bacterial pathogens and how vaccines can substitute antibiotics to protect aquatic animals from various infectious diseases. [ABSTRACT FROM AUTHOR]

In this study, an attempt is made to analyze the published data regarding the effectors of bacterial lysis in the presence of various bacteriolytic enzymes. Despite the differences between such enzymes, it is possible to identify certain general patterns of their action on a highly complex substrate—a living bacterial cell protected by a cell wall and additional complexes of biopolymers associated with it. Chicken and human lysozymes are the best known of these enzymes. They have some structural differences but are generally very similar in properties. Understanding the characteristics of the antibacterial action of bacteriolytic enzymes present both in medications and in the human immune system is extremely important for the development of new approaches to combat bacterial infections, including antibiotic-resistant ones. Moreover, certain logical and methodological approaches used to study bacteriolytic enzymes can be extremely useful for studying and describing other enzymes that affect complex polymer substrates in real biological situations. [ABSTRACT FROM AUTHOR]

In the present study, ten (10) selected bacteria isolated from chasmophytic wild Chenopodium were evaluated for alleviation of drought stress in chickpea. All the bacterial cultures were potential P, K and Zn solubilizer. About 50% of the bacteria could produce Indole-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The bacteria showed wide range of tolerance towards pH, salinity, temperature and osmotic stress. Bacillus paralicheniformis L38, Pseudomonas sp. LN75, Enterobacter hormachei subsp. xiangfengensis LJ89, B. paramycoides L17 and Micrococcus luteus LA9 significantly improved growth and nutrient (N, P, K, Fe and Zn) content in chickpea under water stress during a green house experiment conducted following a completely randomized design (CRD). Application of Microbacterium imperiale LJ10, B. stercoris LN74, Pseudomonas sp. LN75, B. paralicheniformis L38 and E. hormachei subsp. xiangfengensis LJ89 reduced the antioxidant enzymes under water stress. During field experiments conducted following randomized block design (RBD), all the bacterial inoculations improved chickpea yield under water stress. Highest yield (1363 kg ha−1) was obtained in plants inoculated with Pseudomonas sp. LN75. Pseudomonas sp. LN75, B. paralicheniformis L38 and E. hormachei subsp. xiangfengensis LJ89 have potential as microbial stimulants to alleviate the water stress in chickpea. To the best of our knowledge this is the first report of using chasmophyte associated bacteria for alleviation of water stress in a crop plant. [ABSTRACT FROM AUTHOR]

Contractile injection systems (CISs) are prokaryotic phage tail-like nanostructures loading effector proteins that mediate various biological processes. Although CIS functions have been diversified through evolution and hold the great potential as protein delivery systems, the functional characterisation of CISs and their effectors is currently limited to a few CIS lineages. Here, we show that the CISs of Streptomyces davawensis belong to a unique group of bacterial CISs distributed across distant phyla and facilitate sporogenic differentiation of this bacterium. CIS loss results in decreases in extracellular DNA release, biomass accumulation, and spore formation in S. davawensis. CISs load an effector, which is a remote homolog of phage tapemeasure proteins, and its C-terminal domain has endonuclease activity responsible for the CIS-associated phenotypes. Our findings illustrate that CISs can contribute to the reproduction of bacteria through the action of the effector and suggest an evolutionary link between CIS effectors and viral cargos. Bacteria can use contractile injection systems, similar to viral tail structures, to deliver toxic proteins into other cells. Here, Nagakubo et al. identify a related system that modulates sporulation in multicellular Streptomyces bacteria. [ABSTRACT FROM AUTHOR]

Petroleum contamination constitutes a frequent incidence in various petroleum depots in Nigeria. In this study, the polycyclic aromatic hydrocarbons (PAHs) present in soil and water in communities around Petroleum Products Marketing Company (PPMC) Suleja, Nigeria, were evaluated and degraded using indigenous microorganisms. The samples sites were divided into 7 plots from where samples of water and soil were obtained: one within the PPMC depot, five from communities surrounding the depot, and the control 93,000 km from the depot. The microbial counts were determined using spread plate inoculation technique on minimal salt media. The microbial isolates were characterized and identified based on their cultural, biochemical, and molecular characteristics. The potential of the microbial isolates to utilize 0.05 mL of diesel, kerosene, engine oil, and crude oil was determined in a Bushnell Haas Broth, and the biodegradation was determined by total viable cell counts and spectrophotometry. The ability of the isolates to mineralize PAHs was also evaluated in a minimum salt media. The bacterial isolates were species of Streptococcus, Pseudomonas, Staphylococcus, Proteus, Escherichia, and Bacillus, while species of Penicillium, Aspergillus, Mucor, and Rhizopus were isolated among the fungi. Aspergillus niger strain ATCC 1015 and Bacillus thuringiensis strain M43 showed high capacity to utilize the 16 priority PAHs. The pahE1 gene was used by Bacillus thuringiensis, Pseudomonas aeruginosa and A. niger, while Penicillium notatum used pahE2 gene for the degradation of the PAH. The current study identified microbial isolates that can utilize priority PAHs, making them beneficial for oil spill bioremediation in tropical environments. [ABSTRACT FROM AUTHOR]

Background: Microbial communities are crucial for ecosystems. A central goal of microbial ecological research is to simplify the biodiversity in natural environments and quantify the functional roles to explore how the ecosystems respond under different environmental conditions. However, the research on the stability and dynamics of lake microbes in response to repeated warming stress is limited. Methods: To exclude confounding environmental factors, we conducted a 20-day repeated warming simulation experiment to examine the composition and function dynamics of lake microbial communities. Results: Experimental warming significantly altered the community structure of bacteria instead of fungi. Microbial community structure, together with microbial biomass, jointly regulated the function of microbial communities. The plummeting of aerobic denitrifiers Pseudomonadaceae decreased by 99% (P < 0.001) after high temperature, leading to reduced microbial nitrogen metabolism on nitrogen respiration and nitrate respiration. Under warming conditions, the microbial community with higher adaptability showed more positive correlations and less competitive relationships in co-occurrence networks to acclimate to warming. Conclusion: Microbiome composition controlled carbon and nitrogen metabolism, thus determining lake microbial communities' adaptability to heat stress. This study extended our insights on the lake microbial community response and adaptability under warming drivers. [ABSTRACT FROM AUTHOR]

The Himalayan composting toilets (CTs) offer a sustainable solution for converting human faeces (HF) into compost, supplementing the low-fertile land of the region. However, CTs face challenges such as delayed composting processes (6–8 months), increased heavy metal content, and foul odour. Therefore, the current study evaluated biochar-amended psychrotrophic bacteria for HF degradation under low-temperature conditions (10 ± 2 °C). Out of 153 psychrotrophic bacteria isolated from HF compost, 17 bacterial strains were selected based on highest and two or more hydrolytic activities. Furthermore, considering the isolation source, bacterial strains were examined for haemolytic activity, biofilm formation, cytotoxicity and seed germination assay. In total, 14 potential strains belonging to Pseudomonas, Microbacterium, Arthrobacter, Streptomyces, Glutamicibacter, Rhodococcus, Serratia, Exiguobacterium, and Jeotgalicoccus genera were considered safe for both human handling and plants. The composting process was conducted in modified plastic drums at 10 ± 2 °C for 90 days through two treatments: Treatment 1 (T1) involving HF, non-immobilized biochar and cocopeat, and Treatment 2 (T2) involving HF, consortium-immobilized biochar and cocopeat. The consortium-immobilized biochar (T2) degraded HF within 90 days with hemicellulose and cellulose degradation ratios of 73.9% and 62.4%, respectively (p ≤ 0.05). The compost maturation indices like C/N ratio (16.5 ± 1.85), total nitrogen (2.66 ± 0.07), total phosphate (0.4 ± 0.005), total potassium (1.8 ± 0.05) also improved in T2 treatment (p ≤ 0.05). Additionally, T2 was more effective in achieving safe levels of faecal coliforms (< 1000 MPN g−1) and reducing heavy metal content compared to T1. 16S rRNA amplicon-based analysis demonstrated an enhancement of bacterial community diversity in T2, with the presence of Rhodococcus, Pseudomonas, Arthrobacter, and Streptomyces at the end of the composting period promoting HF degradation. Furthermore, T2-fertilized soil showed a germination index (121 ± 0.4, p ≤ 0.05) and stimulated root, shoot and yield by 110%, 45.2%, and 288%, respectively, in pea (Pisum sativum var. AS-10) compared to T1 (49.6%, 19%, and 5.8%, respectively) (p ≤ 0.05). In conclusion, the developed biochar-based formulation proved effective in degrading HF at low temperatures, mitigating foul odours, reducing heavy metals, and enhancing the agronomic value of the final compost. This study presents a promising approach for the sustainable management of HF that can supplement the non-nutritive soil of high-altitude regions. [ABSTRACT FROM AUTHOR]

Gut microbiota can adapt to their host environment by rapidly acquiring new mutations. However, the dynamics of this process are difficult to characterize in dominant gut species in their complex in vivo environment. Here we show that the fine-scale dynamics of genome-wide transposon libraries can enable quantitative inferences of these in vivo evolutionary forces. By analyzing >400,000 lineages across four human Bacteroides strains in gnotobiotic mice, we observed positive selection on thousands of cryptic variants — most of which were unrelated to their original gene knockouts. The spectrum of fitness benefits varied between species, and displayed diverse tradeoffs over time and in different dietary conditions, enabling inferences of their underlying function. These results suggest that within-host adaptations arise from an intense competition between numerous contending variants, which can strongly influence their emergent evolutionary tradeoffs. Here, the authors characterize the fine-scale dynamics of genome-wide insertion libraries across four human Bacteroides strains in gnotobiotic mice, revealing rapid adaptation and fitness tradeoffs when commensal gut bacteria adapt to a new host. [ABSTRACT FROM AUTHOR]

Insects are distributed in many environments on Earth, due to the symbiotic relationships they maintain with various microorganisms. Evolutionary (natural selection, mutations, gene flow, and genetic drift) and ecological (environmental features affecting living things) factors have led to the establishment of a microbiota with domains in all species. Insect symbionts are involved in the production of metabolites throughout their life cycle due to defense and nutrition mechanisms. Therefore, the gut microbiota of insects represents an area of interest for obtaining enzymes, antimicrobial compounds, and probiotics with biotechnological potential. Although the study of insect gut microbiota has been hampered by limited isolation capabilities, several modern techniques now provide insight into their presence in hosts. This review describes advances in isolating insect microorganisms and explores their potential for biotechnological applications. The aim is to contribute to our knowledge of these microorganisms and, at the same time, to highlight the importance of continuing the study of their microbiome and the opportunity for substantial benefits to humankind. [ABSTRACT FROM AUTHOR]

Intraspecific variation in pheromone communication is largely unexplored in Tribolium, but tapping into population divergence in chemical communication will provide a baseline for identifying evolutionary mechanisms associated with insect choice behaviors. To reveal population divergence in pheromone communication for mate choice, the mating rhythm, mating preference and male volatile profiles of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae) were studied. During 10 days after emergence, six geographical populations of T. castaneum exhibited an identical daily or circadian mating rhythm. In the mate choice test, male attraction to females varied significantly within six populations of T. castaneum, while female preference to males did not. Furthermore, male attraction to females was positively correlated with their 4,8-dimethyldecanal (DMD) production. Antibiotic treatment significantly decreased male DMD production and its attraction to females. After gnotobiotic reinoculation of two gut bacteria, Citrobacter freundii and Escherichia coli, to antibiotic-treated males, male DMD production and its attraction to females were almost restored to the normal level. This indicates that: (1) there was detectable divergence in pheromone communication among six populations of T. castaneum, which could be mainly attributed to alterations in male pheromone production rather than changes in female pheromone perception; and (2) gut bacteria could modulate host pheromone communication by interfering with pheromone production. Such knowledge provides further insight into the function and evolution of microbe-insect symbioses and suggests that careful consideration of population divergence is key to understanding the attraction of lures in insect choice tests. [ABSTRACT FROM AUTHOR]