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Microbial Biotechnology Jun 2024The recently discovered Type 9 Secretion System (T9SS) is present in bacteria of the Fibrobacteres-Bacteroidetes-Chlorobi superphylum, which are key constituents of... (Review)
Review
The recently discovered Type 9 Secretion System (T9SS) is present in bacteria of the Fibrobacteres-Bacteroidetes-Chlorobi superphylum, which are key constituents of diverse microbiomes. T9SS is instrumental in the extracellular secretion of over 270,000 proteins, including peptidases, sugar hydrolases, metal ion-binding proteins, and metalloenzymes. These proteins are essential for the interaction of bacteria with their environment. This mini-review explores the extensive array of proteins secreted by the T9SS. It highlights the diverse functions of these proteins, emphasizing their roles in pathogenesis, bacterial interactions, host colonization, and the overall health of the ecosystems inhabited by T9SS-containing bacteria.
Topics: Bacterial Secretion Systems; Bacterial Proteins; Bacteria; Ecosystem; Microbial Interactions
PubMed: 38924452
DOI: 10.1111/1751-7915.14516 -
Science Advances Jun 2024Chronic wounds are a common and costly complication of diabetes, where multifactorial defects contribute to dysregulated skin repair, inflammation, tissue damage, and...
Chronic wounds are a common and costly complication of diabetes, where multifactorial defects contribute to dysregulated skin repair, inflammation, tissue damage, and infection. We previously showed that aspects of the diabetic foot ulcer microbiota were correlated with poor healing outcomes, but many microbial species recovered remain uninvestigated with respect to wound healing. Here, we focused on , a Gram-negative bacterium that is frequently recovered from chronic wounds but rarely causes infection. Treatment of diabetic wounds with accelerated healing during early stages. We investigated the underlying mechanisms and found that treatment promotes reepithelialization of diabetic keratinocytes, a process that is necessary for healing but deficient in chronic wounds. Overexpression of matrix metalloproteinases in diabetes contributes to failed epithelialization, and we found that treatment balances this overexpression to allow proper healing. This work uncovers a mechanism of bacterial-driven wound repair and provides a foundation for the development of microbiota-based wound interventions.
Topics: Alcaligenes faecalis; Wound Healing; Animals; Keratinocytes; Humans; Matrix Metalloproteinases; Diabetic Foot; Mice; Re-Epithelialization; Male
PubMed: 38924411
DOI: 10.1126/sciadv.adj2020 -
PloS One 2024The effects of turbidity and sedimentation stress on early life stages of corals are poorly understood, particularly in Atlantic species. Dredging operations, beach...
The effects of turbidity and sedimentation stress on early life stages of corals are poorly understood, particularly in Atlantic species. Dredging operations, beach nourishment, and other coastal construction activities can increase sedimentation and turbidity in nearby coral reef habitats and have the potential to negatively affect coral larval development and metamorphosis, reducing sexual reproduction success. In this study, we investigated the performance of larvae of the threatened Caribbean coral species Orbicella faveolata exposed to suspended sediments collected from a reef site in southeast Florida recently impacted by dredging (Port of Miami), and compared it to the performance of larvae exposed to sediments collected from the offshore, natal reef of the parent colonies. In a laboratory experiment, we tested whether low and high doses of each of these sediment types affected the survival, settlement, and respiration of coral larvae compared to a no-sediment control treatment. In addition, we analyzed the sediments used in the experiments with 16S rRNA gene amplicon sequencing to assess differences in the microbial communities present in the Port versus Reef sediments, and their potential impact on coral performance. Overall, only O. faveolata larvae exposed to the high-dose Port sediment treatment had significantly lower survival rates compared to the control treatment, suggesting an initial tolerance to elevated suspended sediments. However, significantly lower settlement rates were observed in both Port treatments (low- and high-dose) compared to the control treatment one week after exposure, suggesting strong latent effects. Sediments collected near the Port also contained different microbial communities than Reef sediments, and higher relative abundances of the bacteria Desulfobacterales, which has been associated with coral disease. We hypothesize that differences in microbial communities between the two sediments may be a contributing factor in explaining the observed differences in larval performance. Together, these results suggest that the settlement success and survival of O. faveolata larvae are more readily compromised by encountering port inlet sediments compared to reef sediments, with potentially important consequences for the recruitment success of this species in affected areas.
Topics: Animals; Anthozoa; Larva; Geologic Sediments; Coral Reefs; Endangered Species; RNA, Ribosomal, 16S; Florida; Microbiota
PubMed: 38923956
DOI: 10.1371/journal.pone.0292474 -
Microbial Biotechnology Jun 2024Beauveria bassiana is an entomopathognic fungus, which is widely employed in the biological control of pests. Gene disruption is a common method for studying the...
Beauveria bassiana is an entomopathognic fungus, which is widely employed in the biological control of pests. Gene disruption is a common method for studying the functions of genes involved in fungal development or its interactions with hosts. However, generating gene deletion mutants was a time-consuming work. The transcriptional factor OpS3 has been identified as a positive regulator of a red secondary metabolite oosporein in B. bassiana. In this study, we have designed a new screening system by integrating a constitutive OpS3 expression cassette outside one of the homologous arms of target gene. Ectopic transformants predominantly exhibit a red colour with oosporein production, while knockout mutants appear as white colonies due to the loss of the OpS3 expression cassette caused by recombinant events. This screening strategy was used to obtain the deletion mutants of both tenS and NRPS genes. Correct mutants were obtained by screening fewer than 10 mutants with a positive efficiency ranging from 50% to 75%. This system significantly reduces the workload associated with DNA extraction and PCR amplification, thereby enhancing the efficiency of obtaining correct transformants in B. bassiana.
Topics: Beauveria; Gene Knockout Techniques; Animals; Gene Deletion; Fungal Proteins; Insecta; Genetics, Microbial
PubMed: 38923821
DOI: 10.1111/1751-7915.14512 -
Microbial Biotechnology Jun 2024Pyruvate dehydrogenase (PDH) catalyses the irreversible decarboxylation of pyruvate to acetyl-CoA, which feeds the tricarboxylic acid cycle. We investigated how the loss...
Inactivation of Pseudomonas putida KT2440 pyruvate dehydrogenase relieves catabolite repression and improves the usefulness of this strain for degrading aromatic compounds.
Pyruvate dehydrogenase (PDH) catalyses the irreversible decarboxylation of pyruvate to acetyl-CoA, which feeds the tricarboxylic acid cycle. We investigated how the loss of PDH affects metabolism in Pseudomonas putida. PDH inactivation resulted in a strain unable to utilize compounds whose assimilation converges at pyruvate, including sugars and several amino acids, whereas compounds that generate acetyl-CoA supported growth. PDH inactivation also resulted in the loss of carbon catabolite repression (CCR), which inhibits the assimilation of non-preferred compounds in the presence of other preferred compounds. Pseudomonas putida can degrade many aromatic compounds, most of which produce acetyl-CoA, making it useful for biotransformation and bioremediation. However, the genes involved in these metabolic pathways are often inhibited by CCR when glucose or amino acids are also present. Our results demonstrate that the PDH-null strain can efficiently degrade aromatic compounds even in the presence of other preferred substrates, which the wild-type strain does inefficiently, or not at all. As the loss of PDH limits the assimilation of many sugars and amino acids and relieves the CCR, the PDH-null strain could be useful in biotransformation or bioremediation processes that require growth with mixtures of preferred substrates and aromatic compounds.
Topics: Pseudomonas putida; Catabolite Repression; Pyruvate Dehydrogenase Complex; Hydrocarbons, Aromatic; Biodegradation, Environmental; Acetyl Coenzyme A; Pyruvic Acid; Gene Deletion; Metabolic Networks and Pathways
PubMed: 38923400
DOI: 10.1111/1751-7915.14514 -
Anais Da Academia Brasileira de Ciencias 2024Klebsiella pneumoniae (K. pneumoniae) is a major cause of healthcare-associated infections and plays a prominent role in the widespread antibiotic resistance crisis....
Klebsiella pneumoniae (K. pneumoniae) is a major cause of healthcare-associated infections and plays a prominent role in the widespread antibiotic resistance crisis. Accurate identification of carbapenemases is essential to facilitate effective antibiotic treatment and reduce transmission of K. pneumoniae. This study aimed to detect carbapenemase production in carbapenem-resistant K. pneumoniae strains using phenotypic and genotypic methods. A total of 67 carbapenem-resistant K. pneumoniae strains obtained from various clinical samples were utilized for identification and antimicrobial susceptibility by the Vitek 2 Compact system (Biomerieux, France). Carbapenemase production was determined by using the Polymerase chain reaction, Blue-carba test (BCT) and Carbapenem inactivation method (CIM). Out of the isolates, 59 (88.1%) were positive bla OXA-48, 16 (23.9%) bla IMP, and five (7.5%) were positive bla NDM. No bla KPC genes were detected. The CIM identified 62 (92.5%), BCT identified 63 (94%) of PCR-positive isolates. The sensitivity and specificity of the BCT and the CIM were determined to be 96.7%, 40%, and 96.7%, 25% respectively. The bla OXA-48 gene was found to be the most prevalent in K. pneumoniae isolates. Early identification of carbapenem resistance plays a vital role in designing effective infection control strategies and mitigating the emergence and transmission of carbapenem resistance, thus reducing healthcare-associated infections.
Topics: Klebsiella pneumoniae; Humans; Phenotype; Microbial Sensitivity Tests; Genotype; Anti-Bacterial Agents; Carbapenems; beta-Lactamases; Polymerase Chain Reaction; Bacterial Proteins; Klebsiella Infections; Carbapenem-Resistant Enterobacteriaceae
PubMed: 38922280
DOI: 10.1590/0001-3765202420231322 -
Toxins Jun 2024Pierisin-1 was serendipitously discovered as a strong cytotoxic and apoptosis-inducing protein from pupae of the cabbage butterfly against cancer cell lines. This... (Review)
Review
Pierisin-1 was serendipitously discovered as a strong cytotoxic and apoptosis-inducing protein from pupae of the cabbage butterfly against cancer cell lines. This 98-kDa protein consists of the N-terminal region (27 kDa) and C-terminal region (71 kDa), and analysis of their biological function revealed that pierisin-1 binds to cell surface glycosphingolipids on the C-terminal side, is taken up into the cell, and is cleaved to N- and C-terminal portions, where the N-terminal portion mono-ADP-ribosylates the guanine base of DNA in the presence of NAD to induce cellular genetic mutation and apoptosis. Unlike other ADP-ribosyltransferases, pieisin-1 was first found to exhibit DNA mono-ADP-ribosylating activity and show anti-cancer activity in vitro and in vivo against various cancer cell lines. Pierisin-1 was most abundantly produced during the transition from the final larval stage to the pupal stage of the cabbage butterfly, and this production was regulated by ecdysteroid hormones. This suggests that pierisn-1 might play a pivotal role in the process of metamorphosis. Moreover, pierisin-1 could contribute as a defense factor against parasitization and microbial infections in the cabbage butterfly. Pierisin-like proteins in butterflies were shown to be present not only among the subtribe Pierina but also among the subtribes Aporiina and Appiadina, and pierisin-2, -3, and -4 were identified in these butterflies. Furthermore, DNA ADP-ribosylating activities were found in six different edible clams. Understanding of the biological nature of pierisin-1 with DNA mono-ADP-ribosylating activity could open up exciting avenues for research and potential therapeutic applications, making it a subject of great interest in the field of molecular biology and biotechnology.
Topics: Animals; Butterflies; Insect Proteins; Apoptosis; ADP Ribose Transferases; Humans; Antineoplastic Agents
PubMed: 38922164
DOI: 10.3390/toxins16060270 -
Toxins May 2024Aflatoxin B (AFB) contamination is a food safety issue threatening human health globally. Biodegradation is an effective method for overcoming this problem, and many...
Aflatoxin B (AFB) contamination is a food safety issue threatening human health globally. Biodegradation is an effective method for overcoming this problem, and many microorganisms have been identified as AFB-degrading strains. However, the response mechanisms of these microbes to AFB remain unclear. More degrading enzymes, especially of new types, need to be discovered. In this study, a novel AFB-degrading strain, DDC-4, was isolated using coumarin as the sole carbon source. This strain was identified as through physiological, biochemical, and molecular methods. The strain's degradation activity was predominantly attributable to thermostable extracellular proteins (degradation rate remained approximately 80% at 90 °C) and was augmented by Cu (95.45% AFB was degraded at 48 h). Alpha/beta hydrolase (arylesterase) was selected as candidate AFB-degrading enzymes for the first time as a gene encoding this enzyme was highly expressed in the presence of AFB. Moreover, AFB inhibited many genes involved in the nucleotide synthesis of strain DDC-4, which is possibly the partial molecular mechanism of AFB's toxicity to microorganisms. To survive under this stress, sporulation-related genes were induced in the strain. Altogether, our study identified a novel AFB-degrading strain and explained its response mechanisms to AFB, thereby providing new insights for AFB biodegradation.
Topics: Aflatoxin B1; Bacillus; Biodegradation, Environmental; Bacterial Proteins
PubMed: 38922150
DOI: 10.3390/toxins16060256 -
Toxins May 2024, a Gram-positive anaerobic bacterium, is the leading cause of hospital-acquired antibiotic-associated diarrhea worldwide. The severity of infection (CDI) varies,... (Review)
Review
, a Gram-positive anaerobic bacterium, is the leading cause of hospital-acquired antibiotic-associated diarrhea worldwide. The severity of infection (CDI) varies, ranging from mild diarrhea to life-threatening conditions such as pseudomembranous colitis and toxic megacolon. Central to the pathogenesis of the infection are toxins produced by , with toxin A (TcdA) and toxin B (TcdB) as the main virulence factors. Additionally, some strains produce a third toxin known as transferase (CDT). Toxins damage the colonic epithelium, initiating a cascade of cellular events that lead to inflammation, fluid secretion, and further tissue damage within the colon. Mechanistically, the toxins bind to cell surface receptors, internalize, and then inactivate GTPase proteins, disrupting the organization of the cytoskeleton and affecting various Rho-dependent cellular processes. This results in a loss of epithelial barrier functions and the induction of cell death. The third toxin, CDT, however, functions as a binary actin-ADP-ribosylating toxin, causing actin depolymerization and inducing the formation of microtubule-based protrusions. In this review, we summarize our current understanding of the interaction between toxins and host cells, elucidating the functional consequences of their actions. Furthermore, we will outline how this knowledge forms the basis for developing innovative, toxin-based strategies for treating and preventing CDI.
Topics: Clostridioides difficile; Bacterial Toxins; Host Microbial Interactions; Clostridium Infections; Gene Order; Inflammation; Humans; Animals
PubMed: 38922136
DOI: 10.3390/toxins16060241 -
Toxins May 2024produces fumonisins, which are mycotoxins inhibiting sphingolipid biosynthesis in humans, animals, and other eukaryotes. Fumonisins are presumed virulence factors of...
produces fumonisins, which are mycotoxins inhibiting sphingolipid biosynthesis in humans, animals, and other eukaryotes. Fumonisins are presumed virulence factors of plant pathogens, but may also play a role in interactions between competing fungi. We observed higher resistance to added fumonisin B (FB) in fumonisin-producing than in nonproducing , and likewise between isolates of and differing in production of sphinganine-analog toxins. It has been reported that in , ceramide synthase encoded in the fumonisin biosynthetic gene cluster is responsible for self-resistance. We reinvestigated the role of and by generating a double mutant strain in a background. Nearly unchanged resistance to added FB was observed compared to the parental strain. A recently developed fumonisin-sensitive baker's yeast strain allowed for the testing of candidate ceramide synthases by heterologous expression. The overexpression of the yeast gene, but not , increased fumonisin resistance. High-level resistance was conferred by , but not by . Likewise, strong resistance to FB was caused by overexpression of the presumed "housekeeping" ceramide synthases , , and , located outside the fumonisin cluster, indicating that possesses a redundant set of insensitive targets as a self-resistance mechanism.
Topics: Fumonisins; Fusarium; Oxidoreductases; Drug Resistance, Fungal; Fungal Proteins; Aspergillus; Alternaria
PubMed: 38922130
DOI: 10.3390/toxins16060235