Natural Niche Research Articles

Bio-mimetic deconstruction of the digital business ecosystem

The advent of the Internet Plus era, digital technologies, and the digital economy has instigated profound transformations in the commercial landscape, particularly evident in the systematic reshaping of the Digital Business Ecosystem (DBE), encompassing innovations in business models, norms of commercial conduct, and the exploration of business value. This paper delves into the panoramic view of digital business operations of typical companies to uncover the fundamental structural framework of digital commerce. Through deductive reasoning and drawing upon the theoretical framework of natural niche, we construct a niche model for the digital business ecosystem, thereby achieving a bionic deconstruction of the digital business ecosystem. The significance of this research lies in offering a novel research perspective for enterprises, economic regulatory bodies, and scholars in the field of business management, proposing a systemic approach rooted in niche theory models to competition. This approach provides a fresh theoretical framework for enterprises to devise their own ecological and sustainable development strategies. The key findings are as follows: (1) Most business firms establish competitive advantages by constructing commercial cloud platforms that facilitate internal digital transformation and enable digital synergy with external economic entities; (2) Within the digital business ecosystem, enterprises extend their digital capabilities externally through four modalities: data development, data application, data services, and data manufacturing. Externally, six primary forces and roles shape the ecosystem: suppliers, governments, social institutions, consumers, as well as external and internal industry players; (3) The digital business niche is a multidimensional and hyper volumetric relationship positioning between enterprises and the digital business environment. The niche factors include six dimensions: market, personnel, resources, social relationships, technology, and institutions; (4) Given limited ecological factors, the non-exclusivity between static resource allocation and dynamic technological investments in digital enablement leads to the generalization of property rights boundaries and industrial values within the digital business ecosystem. Consequently, this fosters extensive business applications and diversified business models, thereby resulting in less competition and more cooperation, symbiosis, and complementarity within the digital business niche.

Scaffold-free 3D culture systems for stem cell-based tissue regeneration.

Recent advances in scaffold-free three-dimensional (3D) culture methods have significantly enhanced the potential of stem cell-based therapies in regenerative medicine. This cutting-edge technology circumvents the use of exogenous biomaterial and prevents its associated complications. The 3D culture system preserves crucial intercellular interactions and extracellular matrix support, closely mimicking natural biological niches. Therefore, stem cells cultured in 3D formats exhibit distinct characteristics, showcasing their capabilities in promoting angiogenesis and immunomodulation. This review aims to elucidate foundational technologies and recent breakthroughs in 3D scaffold-free stem cell engineering, offering comprehensive guidance for researchers to advance this technology across various clinical applications. We first introduce the various sources of stem cells and provide a comparative analysis of two-dimensional (2D) and 3D culture systems. Given the advantages of 3D culture systems, we delve into the specific fabrication and harvesting techniques for cell sheets and spheroids. Furthermore, we explore their applications in pre-clinical studies, particularly in large animal models and clinical trials. We also discuss multidisciplinary strategies to overcome existing limitations such as insufficient efficacy, hostile microenvironments, and the need for scalability and standardization of stem cell-based products.

Enterococcal-host interactions in the gastrointestinal tract and beyond.

The gastrointestinal tract (GIT) is typically considered the natural niche of enterococci. However, these bacteria also inhabit extraintestinal tissues, where they can disrupt organ physiology and cause life-threatening infections. Here, we discuss how enterococci, primarily Enterococcus faecalis, interact with the intestine and other host anatomical locations such as the oral cavity, heart, liver, kidney, and vaginal tract. The metabolic flexibility of these bacteria allows them to quickly adapt to new environments, promoting their persistence in diverse tissues. In transitioning from commensals to pathogens, enterococci must overcome harsh conditions such as nutrient competition, exposure to antimicrobials, and immune pressure. Therefore, enterococci have evolved multiple mechanisms to adhere, colonize, persist, and endure these challenges in the host. This review provides a comprehensive overview of how enterococci interact with diverse host cells and tissues across multiple organ systems, highlighting the key molecular pathways that mediate enterococcal adaptation, persistence, and pathogenic behavior.

Challenges faced by spotted seals born in captivity and released into the wild

The artificial reproduction of endangered marine species populations is becoming increasingly crucial. Determining the potential for reintegration into their natural ecological niche remains a persistent obstacle in conservation biology. Spotted seals (Phoca largha) are a flagship species in the Chinese marine ecosystem. Efforts have been made to artificially breed them to prevent local extinction. Our study monitored 18 captive-born (nine) and rehabilitated (nine) individuals released into the Bohai Sea between 2010 and 2020. We examined the ecological niche-seeking behavior of captive-born seals (CS) using rehabilitated wild seals (RS) as benchmarks. It encompassed three oceanic gradients, habitat patterns, and potential threats. The findings demonstrated that CS did not return to the appropriate latitudes, horizontals, and sea surface salinity gradients in the ocean. Despite a larger potential habitat area for CS, it exhibited high temporal variability (with an average monthly fluctuation of 53 %) and demonstrated limited spatial overlap with the RS habitat (27 % overlap in July), and four indices, including the Splitting and Global Moran's Indices indicated a higher level of habitat fragmentation. Additionally, the number of shipping hotspots and collision risk within the CS habitats were twice those of the RS. These findings suggest that the released CS did not fully integrate into its native ecological niche. Our objective is to offer a pragmatic approach and framework for monitoring and assessing marine species released into the ocean.

Testicular Cells Derived Conditioned Medium Supports Germ Cell Differentiation of Human Embryonic Stem Cells.

There are ethical and technical challenges in studying human germ cell development. Therefore, the aim of the study is in vitro differentiation of human embryonic stem cells (hESCs), as pluripotent cells, to the germ cells which is a valuable tool for studying molecular and cellular aspects of gametogenesis and understanding causes of infertility. In this experimental study, two different complete media [Dulbecco's Modified Eagle Medium (DMEM)+20% fetal bovine serum (FBS) and embryoid bodies (EBs) medium; KOSR/HES without basic fibroblast growth factor (bFGF)] were used in the both of test groups using testicular cells derived conditioned medium (TCCM) and control groups spontaneously differentiated (SD). Thereby, EBs from hESCs (Yazd2; 46XY) were cultured in different conditions EB medium; EB medium and conditioned EB medium; EB medium, DMEM, and FBS without conditioning; EB medium, conditioned DMEM, and FBS medium. EBs were collected after 4, 7, and 14 days and their gene expression profiles were assessed and compared to hESCs, as day 0, using IF and relative reverse transcription quantitative polymerase chain reaction (RT-qPCR). An increase in the gametogenesis gene expression level in TCCM groups was showed in comparison with SD groups. Additionally, immunostaining of differentiated cells in all groups showed in vitro gametogenesis (IVG). Our findings showed that human TCCM could be used as a natural niche for in vitro male and female germ cell development. However, further studies are needed to define the factors and metabolites within the human TCCM.

Infection of human organoids supports an intestinal niche for Chlamydia trachomatis.

Several reports suggest that intestinal tissue may be a natural niche for Chlamydia trachomatis infection and a reservoir for persistent infections in the human body. Due to the human specificity of the pathogen and the lack of suitable host models, there is limited knowledge on this topic. In our study, we modelled the course of the chlamydial infection in human primary gastrointestinal (GI) epithelial cells originating from patient-derived organoids. We show that GI cells are resistant to apical infection and C. trachomatis needs access to the basolateral membrane to establish an infection. Transmission electron microscopy analysis reveals the presence of both normal as well as aberrant chlamydial developmental forms in the infected cells, suggesting a possible cell-type specific nature of the infection. Furthermore, we show that the plasmid-encoded Pgp3 is an important virulence factor for the infection of human GI cells. This is the first report of C. trachomatis infection in human primary intestinal epithelial cells supporting a possible niche for chlamydial infection in the human intestinal tissue.

Native CRISPR-Cas-based programmable multiplex gene repression in Klebsiella variicola.

Klebsiella variicola is a Gram-negative bacterium that is frequently isolated from a wide variety of natural niches. It is a ubiquitous opportunistic pathogen that can cause diverse infections in plants, animals, and humans. It also has significant biotechnological potential. However, due to the lack of efficient genetic tools, the molecular basis contributing to the pathogenesis and beneficial activities of K. variicola remains poorly understood. In this study, we found and characterized a native type I-E CRISPR-Cas system in a recently isolated K. variicola strain KV-1. The system cannot cleave target DNA sequences due to the inactivation of the Cas3 nuclease by a transposable element but retains the activity of the crRNA-guided Cascade binding to the target DNA sequence. A targeting plasmid carrying a mini-CRISPR to encode a crRNA was designed and introduced into the KV-1 strain, which successfully repurposed the native type I-E CRISPR-Cas system to inhibit the expression of the target gene efficiently and specifically. Moreover, by creating a mini-CRISPR to encode multiple crRNAs, multiplex gene repression was achieved by providing a single targeting plasmid. This work provides the first native CRISPR-Cas-based tool for programmable multiplex gene repression in K. variicola, which will facilitate studying the pathogenic mechanism of K. variicola and enable metabolic engineering to produce valuable bioproducts.

Biogeographical distribution and community assembly of Myxococcota in mangrove sediments

BackgroundMyxococcota, characterized by their distinct social lifestyles, are widely distributed micro-predators in global sediments. They can feed on a wide range of bacterial, archaeal, and fungal prey. Myxococcota are capable of producing diverse secondary metabolites, playing key roles in microbial food webs, and regulating the microbial community structures in different ecosystems. However, Myxococcota are rarely pure cultured due to the challenging and stringent culturing conditions. Their natural distribution, niche differentiation, and predator–prey relationships in a specific habitat are poorly understood.ResultsIn this study, we conducted a comprehensive analysis of the 16S rRNA gene sequence data from public databases and our collection. We compared the abundance, diversity, and distribution patterns of Myxococcota in various habitats, with a specific focus on mangroves. We found that Myxococcota accounted for 1.45% of the total prokaryotes in global sediments based on the abundance of 16S rRNA genes. Myxococcota are abundant and diverse in mangrove sediments. They tend to be more generalistic in mangroves than in other habitats due to their wide niche breadth. Besides, the deterministic processes (variable selection) influenced the assembly of mangrove Myxococcota communities significantly more than stochastic processes. Further, we determined that environmental factors explained a greater amount of total community variation in mangrove Myxococcota than geographical variables (latitude and sediment depth). In the end, through the analysis of microbial co-occurrence networks, Myxococcota emerges as a key component and functions as a connector in the mangrove microbial community.ConclusionsOur study enhances comprehension of mangrove Myxococcota's biogeography, assembly patterns, driving factors, and co-occurrence relationships, as well as highlights their unique niche and ecological importance in mangrove sediments.

Unpacking Alternative Features of the Bacterial Chemotaxis System.

The bacterial chemotaxis system is one of the best-understood cellular pathways and serves as the model for signal transduction systems. Most chemotaxis research has been conducted with transmembrane chemotaxis systems from Escherichia coli and has established paradigms of the system that were thought to be universal. However, emerging research has revealed that many bacteria possess alternative features of their chemotaxis system, demonstrating that these systems are likely more complex than previously assumed. Here, we compare the canonical chemotaxis system of E. coli with systems that diverge in supramolecular architecture, sensory mechanisms, and protein composition. The alternative features have likely evolved to accommodate chemical specificities of natural niches and cell morphologies. Collectively, these studies demonstrate that bacterial chemotaxis systems are a rapidly expanding field that offers many new opportunities to explore this exceedingly diverse system.

Sphaerotilus uruguayifluvii sp. nov., a novel filamentous bacterium isolated from river water.

Strain C29T, a Gram-staining-negative, straight rod occurring singly, in pairs or short chains, was isolated from floating filamentous biomass of the Uruguay River. The strain was catalase and oxidase positive, chemoorganotrophic, strictly aerobic, non-motile, and grew at pH 6.0-9.0, 15-45°C, and 0-0.5% (w/v) NaCl. Polyhydroxybutyrate was accumulated in nutrient-limited conditions. Phylogenetic analysis based on the 16S rRNA gene revealed that strain C29T had the highest sequence similarity with Leptothrix discophora SS-1T (97.82%), Ideonella livida TBM-1T (97.82%), Vitreoscilla filiformis L1401-2T (97.52%), Sphaerotilus sulfidivorans D-501T (97.50%) and Sphaerotilus natans DSM6575T(97.46%). Other type strains with validly published names had similarities below 97.46%. Further phylogenomic analysis showed that strain C29T was affiliated to the family Sphaerotilaceae. Average nucleotide identity (ANI) and in silico DNA-DNA hybridization (dDDH) values with its phylogenetic relatives were lower than 91 and 41%, respectively, revealing that strain C29T represented a new species. The DNA G + C content of strain C29T was 70.9%. The annotation of the genome of the novel strain shows it possessed genes for the degradation of aromatic compounds. It also contained genes that encode sigma factors involved in response regulation of stress resistance, which is an important function for adaptation and survival in natural niches. Based on the results of the phylogenetic and phenotypic analyses, we propose that strain C29T represents a novel species, for which the name Sphaerotilus uruguayifluvii sp. nov. is proposed. The type strain is C29T (= CCM 9043T = DSM 113250T).

Engineered Cyanobacteria-Based Living Materials for Bioremediation of Heavy Metals Both In Vitro and In Vivo.

The pollution caused by heavy metals (HMs) represents a global concern due to their serious environmental threat. Photosynthetic cyanobacteria have a natural niche and the ability to remediate HMs such as cadmium. However, their practical application is hindered by a low tolerance to HMs and issues related to recycling. In response to these challenges, this study focuses on the development and evaluation of engineered cyanobacteria-based living materials for HMs bioremediation. Genes encoding phytochelatins (PCSs) and metallothioneins (MTs) were introduced into the model cyanobacterium Synechocystis sp. PCC 6803, creating PM/6803. The strain exhibited improved tolerance to multiple HMs and effectively removed a combination of Cd2+, Zn2+, and Cu2+. Using Cd2+ as a representative, PM/6803 achieved a bioremediation rate of approximately 21 μg of Cd2+/OD750 under the given test conditions. To facilitate its controllable application, PM/6803 was encapsulated using sodium alginate-based hydrogels (PM/6803@SA) to create "living materials" with different shapes. This system was feasible, biocompatible, and effective for removing Cd2+ under simulated conditions of zebrafish and mice models. Briefly, in vitro application of PM/6803@SA efficiently rescued zebrafish from polluted water containing Cd2+, while in vivo use of PM/6803@SA significantly decreased the Cd2+ content in mice bodies and restored their active behavior. The study offers feasible strategies for HMs bioremediation using the interesting biomaterials of engineered cyanobacteria both in vitro and in vivo.

Secondary sexual dimorphism and ontogenetic shifts in habitat use by the lesser guitarfish Zapteryx brevirostris.

Sexual dimorphisms are generated by divergent processes, such as natural or sexual selection and niche convergence. Males and females of the lesser guitarfish, Zapteryx brevirostris, present morphological differences in their discs, and the relationships with the species biology and ecology were unrecognized. Analysing the morphometry of 201 specimens and the influence of bottom features on the frequencies of 188 specimens among life stages and sexes, we found strong evidence that gonadal maturation leads to dimorphisms on discs, validating a concavity on male pectoral fins as a secondary sexual dimorphism and rejecting the hypothesis that such dimorphisms were related to ecological pressures. The principal component analysis (PCA) and permutational MANOVA (PERMANOVA) analyses revealed that males and females shared similar body aspects until they reached maturity, mainly due to lower variations in WD, WR, LD, DPRO, and LSC at younger life stages. The relationships of these variables with LT corroborate the former results, showing a changing point around LT > 30 cm where females started to attain larger measurements than males. Moreover, we revealed ontogenetic shifts, with adults from both sexes exploring different habitats than juveniles and subadults. Differences in frequencies of each life stage were best explained by organic matter (OM) with the adults exploring bottom habitats of higher concentrations of OM than juveniles and subadults, strengthening the assumption that body differences between sexes are not related to ecological pressures. These results bring not only new insights about the possible advantages that those morphometric differences provide to males while mating but also information about the abiotic influences on species distribution, which, along with knowledge of local oceanographic dynamics and benthic community patterns, would inform actions for species conservation.

Metataxonomic analysis of endophytic bacteria of blackberry (Rubus ulmifolius Schott) across tissues and environmental conditions

(1) Background: Endophytic bacteria represent an important component of plant wellness. They have been widely studied for their involvement in plant development and enhancement of stress tolerance. In this work, the endophytic communities of roots, stems, and leaves of blackberry (Rubus ulmifolius Schott) were studied in three different niches: natural, riverside, and human-impacted niches. (2) Results: The microbiome composition revealed that Sphingomonadaceae was the most abundant family in all samples, accounting for 9.4–45.8%. In contrast, other families seem to be linked to a specific tissue or niche. Families Microbacteriaceae and Hymenobacteraceae increased their presence in stem and leaf samples, while Burkholderiaceae abundance was important in riverside samples. Alpha and beta diversity analyses showed that root samples were the most diverse, and they gathered together in the same cluster, apart from the rest of the samples. (3) Conclusions: The analysis of the microbiome of R. ulmifolius plants revealed that the composition was essentially the same in different niches; the differences were primarily influenced by plant tissue factors with a core genome dominated by Sphingomonadaceae. Additionally, it was observed that R. ulmifolius can select its own microbiome, and this remains constant in all tissues evaluated regardless the niche of sampling.

Sweet dreams could be made of this: carbohydrate-responsive element-binding protein (ChREBP) as a target for hepatocellular carcinoma therapy.

Rewiring of cellular metabolism is now fully recognized as a hallmark of cancer. Tumor cells reprogram metabolic pathways to meet the energetic and macromolecular demands to support unrestricted growth and survival under unfavorable conditions. It is becoming apparent that these adaptations underpin most of the traits that define a cancer cell's identity, including the ability to avoid immune surveillance, endure nutrient and oxygen restrictions, detach and migrate from their natural histological niche, and avert human-made aggressions (i.e., therapy). In a recent study, Benichou and collaborators identify carbohydrate-responsive element-binding protein (ChREBP), a master regulator of physiological glucose metabolism, as an oncogene in hepatocellular carcinoma (HCC) development. Upregulation of ChREBP expression results in a self-stimulatory loop interconnecting PI3K/AKT signaling and glucose metabolism to feed fatty acid and nucleotide synthesis supporting tumorigenesis. Importantly, pharmacological inhibition of ChREBP activity quells in vivo HCC tumor growth without causing systemic toxicity. This study identifies novel oncometabolic pathways and open up new avenues to improve the treatment of a deadly tumor.

The Fe-S cluster biosynthesis in Enterococcus faecium is essential for anaerobic growth and gastrointestinal colonization

ABSTRACT The facultative anaerobic Gram-positive bacterium Enterococcus faecium is a ubiquitous member of the human gut microbiota. However, it has gradually evolved into a pathogenic and multidrug resistant lineage that causes nosocomial infections. The establishment of high-level intestinal colonization by enterococci represents a critical step of infection. The majority of current research on Enterococcus has been conducted under aerobic conditions, while limited attention has been given to its physiological characteristics in anaerobic environments, which reflects its natural colonization niche in the gut. In this study, a high-density transposon mutant library containing 26,620 distinct insertion sites was constructed. Tn-seq analysis identified six genes that significantly contribute to growth under anaerobic conditions. Under anaerobic conditions, deletion of sufB (encoding Fe-S cluster assembly protein B) results in more extensive and significant impairments on carbohydrate metabolism compared to aerobic conditions. Consistently, the pathways involved in this utilization-restricted carbohydrates were mostly expressed at significantly lower levels in mutant compared to wild-type under anaerobic conditions. Moreover, deletion of sufB or pflA (encoding pyruvate formate lyase-activating protein A) led to failure of gastrointestinal colonization in mice. These findings contribute to our understanding of the mechanisms by which E. faecium maintains proliferation under anaerobic conditions and establishes colonization in the gut.

The transcriptome response of Enterobacter sp. S-33 is modulated by low pH-stress.

Acidic environments naturally occur worldwide and uncontrolled use of agricultural practices may also cause acidification of soils. The development of acidic conditions disturbs the establishment of efficient microbial populations in their natural niches. The survival of Enterobacter species under acidic stress remains poorly understood. This study aimed to investigate the survival of an environmental isolate Enterobacter sp. S-33 under acidic stress and to identify the various genes involved in stress protection at the global gene transcription level. The obtained results provide new targets that will allow understanding the in-depth mechanisms involved in the adaptation of bacteria to environmental pH changes. We used the next-generation sequencing (NGS) method to analyze the expression (up-regulation & down-regulation) of genes under varying pH conditions. A total of 4214 genes were differentially expressed under acidic conditions (pH 5.0), with 294 up-regulated and 167 down-regulated. At pH 6.0, 50 genes were significantly expressed, of which 34 and 16 were identified as up-regulated and down-regulated, respectively. Many of the up-regulated genes were involved in carbohydrate metabolism, amino acid transport & metabolism, and the most down-regulated genes were related to post-translational modification, lipid transport & metabolism, etc. The observed transcriptomic regulation of genes and pathways identified that Enterobacter reduced its post-translational modification, lipid transport & metabolism, and increased carbohydrate metabolism, amino acid metabolism & transport, energy production & conversion to adapt and grow in acidic stress. The present work provides in-depth information on the characterization of genes associated with tolerance or adaptation to acidic stress of Enterobacter bacterium.

Exploiting Natural Niches with Neuroprotective Properties: A Comprehensive Review.

Natural products from mushrooms, plants, microalgae, and cyanobacteria have been intensively explored and studied for their preventive or therapeutic potential. Among age-related pathologies, neurodegenerative diseases (such as Alzheimer's and Parkinson's diseases) represent a worldwide health and social problem. Since several pathological mechanisms are associated with neurodegeneration, promising strategies against neurodegenerative diseases are aimed to target multiple processes. These approaches usually avoid premature cell death and the loss of function of damaged neurons. This review focuses attention on the preventive and therapeutic potential of several compounds derived from natural sources, which could be exploited for their neuroprotective effect. Curcumin, resveratrol, ergothioneine, and phycocyanin are presented as examples of successful approaches, with a special focus on possible strategies to improve their delivery to the brain.

Natural Diversity of Cuticular Pheromones in a Local Population of Drosophila after Laboratory Acclimation.

Experimental studies of insects are often based on strains raised for many generations in constant laboratory conditions. However, laboratory acclimation could reduce species diversity reflecting adaptation to varied natural niches. Hydrocarbons covering the insect cuticle (cuticular hydrocarbons; CHCs) are reliable adaptation markers. They are involved in dehydration reduction and protection against harmful factors. CHCs can also be involved in chemical communication principally related to reproduction. However, the diversity of CHC profiles in nature and their evolution in the laboratory have rarely been investigated. Here, we sampled CHC natural diversity in Drosophila melanogaster flies from a particular location in a temperate region. We also measured cis-Vaccenyl acetate, a male-specific volatile pheromone. After trapping flies using varied fruit baits, we set up 21 D. melanogaster lines and analysed their pheromones at capture and after 1 to 40 generations in the laboratory. Under laboratory conditions, the broad initial pheromonal diversity found in male and female flies rapidly changed and became more limited. In some females, we detected CHCs only reported in tropical populations: the presence of flies with a novel CHC profile may reflect the rapid adaptation of this cosmopolitan species to global warming in a temperate area.

IgA-mediated control of host-microbial interaction during weaning reaction influences gut inflammation.

The mechanisms of how host-microbe mutualistic relationships are established at weaning contingently upon B-cell surveillance remain inadequately elucidated. We found that CD138+ plasmacyte (PC)-mediated promotion of IgA response regulates the symbiosis between Bacteroides uniformis (B. uniformis) and the host during the weaning period. The IgA-skewed response of CD138+ PCs is essential for B. uniformis to occupy a defined gut luminal niche, thereby fostering stable colonization. Furthermore, B. uniformis within the natural gut niche was perturbed in the absence of IgA, resulting in exacerbated gut inflammation in IgA-deficient mice and weaned piglets. Thus, we propose that the priming and maintenance of intestinal IgA response from CD138+ PCs are required for host-microbial symbiosis, whereas the perturbation of which would enhance inflammation in weaning process.

AHL-Based Quorum Sensing Regulates the Biosynthesis of a Variety of Bioactive Molecules in Bacteria.

Bacteria are social microorganisms that use communication systems known as quorum sensing (QS) to regulate diverse cellular behaviors including the production of various secreted molecules. Bacterial secondary metabolites are widely studied for their bioactivities including antibiotic, antifungal, antiparasitic, and cytotoxic compounds. Besides playing a crucial role in natural bacterial niches and intermicrobial competition by targeting neighboring organisms and conferring survival advantages to the producer, these bioactive molecules may be of prime interest to develop new antimicrobials or anticancer therapies. This review focuses on bioactive compounds produced under acyl homoserine lactone-based QS regulation by Gram-negative bacteria that are pathogenic to humans and animals, including the Burkholderia, Serratia, Pseudomonas, Chromobacterium, and Pseudoalteromonas genera. The synthesis, regulation, chemical nature, biocidal effects, and potential applications of these identified toxic molecules are presented and discussed in light of their role in microbial interactions.