MicrobZoo®

🦠 MicrobZoo® ✨The mitochondrial respiratory chain from Rhodotorula mucilaginosa, an extremophile yeast Rhodotorula mucilaginosa survives extreme conditions through several mechanisms, among them its carotenoid production and its branched mitochondrial respiratory chain (RC). Here, the branched RC composition was analyzed by biochemical and complexome profiling approaches. Expression of the different RC components varied depending on the growth phase and the carbon source present in the medium. R. mucilaginosa RC is constituted by all four orthodox respiratory complexes (CI to CIV) plus several alternative oxidoreductases, in particular two type-II NADH dehydrogenases (NDH2) and one alternative oxidase (AOX). Unlike others, in this yeast the activities of the orthodox and alternative respiratory complexes decreased in the stationary phase. We propose that the branched RC adaptability is an important factor for survival in extreme environmental conditions; thus, contributing to the exceptional resilience of R. mucilaginosa. __________________________________________ #genetics #Instagram #hospital #teacher #pharmacy #medical #medicine #HD #researcher #student #university #Harvard #microbiology #cell #biology #molecular

🔬 MicrobZoo® ✨Control of Escherichia coli in Poultry Using the In Ovo Injection Technique Pathogens, such as Escherichia coli (E. coli), have been identified as significant causes of poultry mortality. Poultry can serve as potential sources of E. coli transmission, even when asymptomatic, posing a substantial threat to food safety and human health. The in ovo administration of antimicrobials is crucial for preventing and/or effectively combating acute and chronic infections caused by poultry pathogens. To achieve this goal, it is critical that antimicrobials are properly injected into embryonic fluids, such as the amnion, to reach target tissues and trigger robust antimicrobial responses. Several protocols based on antimicrobials were evaluated to meet these requirements. This review analyzed the impacts of antimicrobial substances injected in ovo on the control of E. coli in poultry. The reduction in infection rates, resulting from the implementation of in ovo antimicrobials, combined with efforts aimed at hygienic-sanitary action plans in poultry sheds, reinforces confidence that E. coli can be contained before causing large scale damage. For example, antimicrobial peptides and probiotics have shown potential to provide protection to poultry against infections caused by E. coli. Issues related to the toxicity and bacterial resistance of many synthetic chemical compounds represent challenges that need to be overcome before the commercial application of in ovo injection protocols focused on microbiological control. __________________________________________________________ #Instagram #hospital #teacher #pharmacy #genetics #medicine #medical #microbiology #cell #biology #molecular #university #studentlife #Harvard #bacteria #research #researcher #science

🦠 MicrobZoo® 🎯Heyndrickxia coagulans (formerly Bacillus coagulans) is a lactic acid–forming bacterial species. This species was transferred to Weizmannia in 2020, then to Heyndrickxia in 2023. H. coagulans is a Gram-positive, catalase-positive, spore-forming, motile, facultative anaerobe rod that measures approximately 0.9 μm by 3.0 μm to 5.0 μm. It may appear Gram negative when entering the stationary phase of growth. The species was first isolated and described in 1915 by B.W. Hammer at the Iowa Agricultural Experiment Station as a cause of an outbreak of coagulation in evaporated milk packed by an Iowa condensary. Separately isolated in 1935 and described as Lactobacillus sporogenes in the fifth edition of Bergey's Manual of Systematic Bacteriology, it exhibits characteristics typical of both genera Lactobacillus and Bacillus; its taxonomic position between the families Lactobacillaceae and Bacillaceae was often debated. However, in the seventh edition of Bergey's, it was finally transferred to the genus Bacillus. DNA-based technology was used in distinguishing between the two genera of bacteria, which are morphologically similar and possess similar physiological and biochemical characteristics. In 2020, further genetic evidence shows that it is sufficiently different from other members of Bacillus to be transferred into its own genus. As a result, it became the type species of Weizmannia. In 2023, even further genetic evidence shows that Weizmannia was not sufficiently distinct from Heyndrickxia to be an independent genus; as a result, all members of Weizmannia was moved to Heyndrickxia.

🌿 MicrobZoo® 🍃 #Pseudomonas fluorescens is a common Gram-negative, rod-shaped bacterium. It belongs to the Pseudomonas genus; 16S rRNA analysis as well as phylogenomic analysis has placed P. fluorescens in the P. fluorescens group within the genus, to which it lends its name. Pseudomonas fluorescens is increasingly recognized for its #biocontrol properties in #agriculture. Recent studies have demonstrated its effectiveness in controlling a variety of #plant #pathogens, including #fungi, nematodes, and bacteria. The bacterium’s ability to produce secondary metabolites, such as antibiotics and phytohormones, contributes to its #biocontrol efficacy. These metabolites not only inhibit the growth of pathogens but also induce systemic #resistance in plants, enhancing their #natural #defense #mechanisms. Moreover, the application of P. fluorescens as a biocontrol agent has been shown to be a sustainable alternative to #chemical #pesticides, promoting #environmental #health and reducing the #ecological footprint of agricultural practices. The ongoing #research in this field is focused on optimizing the use of P. fluorescens for biocontrol and understanding the underlying #mechanisms that enable it to protect crops from #diseases.

🦠 MicrobZoo® 🧫Plasmodium falciparum Plasmodium falciparum is the etiological agent of malaria tropica, the leading cause of death due to a vector-borne infectious disease, claiming 0.5 million lives every year. The single-cell eukaryote undergoes a complex life cycle and is an obligate intracellular parasite of hepatocytes (clinically silent) and erythrocytes (disease causing). An infection can progress to a wide range of pathologies, including severe anemia and cerebral malaria, which can lead to death. P. falciparum repeatedly replicates over the course of 48 h inside erythrocytes, resulting in exponential growth and rapid disease progression. As the single most important infectious disease afflicting children, no other pathogen has exerted a higher selection pressure on the human genome. Over 20 polymorphisms, including the sickle-cell trait, have been selected in human populations, despite severe fitness costs, since they offer protection against fatal P. falciparum infections. No effective vaccine exists, but several curative treatments are available. __________________________________________________ #biology #microorganism #laboratory #agar #fungi #biotech #microbzoo #virus #medicine #medical #student #microbial #instagram #biotech #university #researcher #research #article #RNA #technology

🦠 MicrobZoo® ✨Pseudomonas aeruginosa ExoS and ExoT ExoS and ExoT are bi-functional type-III cytotoxins of Pseudomonas aeruginosa that share 76% primary amino acid homology and contain N-terminal RhoGAP domains and C-terminal ADP-ribosylation domains. The Rho GAP activities of ExoS and ExoT appear to be biochemically and biologically identical, targeting Rho, Rac, and Cdc42. Expression of the RhoGAP domain in mammalian cells results in the disruption of the actin cytoskeleton and interference of phagocytosis. Expression of the ADP-ribosyltransferase domain of ExoS elicits a cytotoxic phenotype in cultured cells, while expression of ExoT appears to interfere with host cell phagocytic activity. Recent studies showed that ExoS and ExoT ADP-ribosylate different substrates. While ExoS has poly-substrate specificity and can ADP-ribosylate numerous host proteins, ExoT ADP-ribosylates a more restricted subset of host proteins including the Crk proteins. Protein modeling predicts that electrostatic interactions contribute to the substrate specificity of the ADP-ribosyltransferase domains of ExoS and ExoT. _________________________________________________ #biology #microorganism #laboratory #agar #fungi #biotech #university #researcher #research #chemist #laborant #scientist #micology #pharmacy #science #microbzoo #virus #medicine #medical #student

🦠 MicrobZoo® 🧫Mitochondrial respiratory supercomplexes of the yeast Saccharomyces cerevisiae The functional and structural relationship among the individual components of the mitochondrial respiratory chain constitutes a central aspect of our understanding of aerobic catabolism. This interplay has been a subject of intense debate for over 50 years. It is well established that individual respiratory enzymes associate into higher-order structures known as respiratory supercomplexes, which represent the evolutionarily conserved organizing principle of the mitochondrial respiratory chain. In the yeast Saccharomyces cerevisiae, supercomplexes are formed by a complex III homodimer flanked by one or two complex IV monomers, and their high-resolution structures have been recently elucidated. Despite the wealth of structural information, several proposed supercomplex functions remain speculative and our understanding of their physiological relevance is still limited. Recent advances in the field were made possible by the construction of yeast strains where the association of complex III and IV into supercomplexes is impeded, leading to diminished respiratory capacity and compromised cellular competitive fitness. Here, we discuss the experimental evidence and hypotheses relative to the functional roles of yeast respiratory supercomplexes. Moreover, we review the current models of yeast complex III and IV assembly in the context of supercomplex formation and highlight the data scattered throughout the literature suggesting the existence of cross talk between their biogenetic processes. ______________________________________________________ #biology #microorganism #laboratory #agar #fungi #biotech #microbzoo #virus #medicine #medical #student #microbial #instagram #biotech #university #researcher #research #chemist #germs #fungi

🦠 MicrobZoo® 🧫Hemolysis is the breakdown of red blood cells. The ability of bacterial colonies to induce hemolysis when grown on blood agar is used to classify certain microorganisms. This is particularly useful in classifying streptococcal species. A substance that causes hemolysis is a hemolysin. 🔗Alpha-hemolysis When alpha-hemolysis (α-hemolysis) is present, the agar under the colony is light and greenish. Streptococcus pneumoniae and a group of oral streptococci display alpha hemolysis. This is sometimes called green hemolysis because of the color change in the agar. Other synonymous terms are incomplete hemolysis and partial hemolysis. Alpha hemolysis is caused by hydrogen peroxide produced by the bacterium, oxidizing hemoglobin producing the green oxidized derivative methemoglobin. 🔗Beta-hemolysis Beta-hemolysis (β-hemolysis), sometimes called complete hemolysis, is a complete lysis of red cells in the media around and under the colonies: the area appears lightened (yellow) and transparent. Streptolysin, an exotoxin, is the enzyme produced by the bacteria which causes the complete lysis of red blood cells. There are two types of streptolysin: Streptolysin O (SLO) and streptolysin S (SLS). Streptolysin O is an oxygen-sensitive cytotoxin, secreted by most Group A streptococcus (GAS) and Streptococcus dysgalactiae, and interacts with cholesterol in the membrane of eukaryotic cells (mainly red and white blood cells, macrophages, and platelets), and usually results in β-hemolysis under the surface of blood agar. 🔗Gamma-hemolysis If an organism does not induce hemolysis, the agar under and around the colony is unchanged, and the organism is called non-hemolytic or said to display gamma-hemolysis. Enterococcus faecalis, Staphylococcus saprophyticus, and Staphylococcus epidermidis display gamma hemolysis. ___________________________________________________ #biology #microorganism #laboratory #agar #fungi #biotech #microbzoo #virus #medicine #medical #student #microbial #instagram #biotech #university #researcher #research #Chile #India #Mexico #Germany #scientist #micology

🛸 MicrobZoo® ✨Staphylococcus aureus mutants resistant to the feed-additive monensin show increased virulence and altered purine metabolism Ionophores are antibacterial compounds that affect bacterial growth by changing intracellular concentrations of the essential cations, sodium and potassium. They are extensively used in animal husbandry to increase productivity and reduce infectious diseases, but our understanding of the potential for and effects of resistance development to ionophores is poorly known. Thus, given their widespread global usage, it is important to determine the potential negative consequences of ionophore use on human and animal health. In this study, we demonstrate that exposure to the ionophore monensin can select for resistant mutants in the human and animal pathogen Staphylococcus aureus, with a majority of the resistant mutants showing increased growth rates in vitro and/or in mice. Whole-genome sequencing and proteomic analysis of the resistant mutants show that the resistance phenotype is associated with de-repression of de novo purine synthesis, which could be achieved through mutations in different transcriptional regulators including mutations in the gene purR, the repressor of the purine de novo synthesis pathway. This study shows that mutants with reduced susceptibility to the ionophore monensin can be readily selected and highlights an unexplored link between ionophore resistance, purine metabolism, and fitness in pathogenic bacteria. __________________________________________________ #biology #microorganism #laboratory #agar #fungi #biotech #microbzoo #virus #medicine #medical #student #microbial #tv

🦠 MicrobZoo® 🛸Staphylococcus aureus colonisation and strategies for decolonisation Staphylococcus aureus is a leading cause of death by infectious diseases worldwide. Treatment of S aureus infections is difficult due to widespread antibiotic resistance, necessitating alternative approaches and measures for prevention of infection. Because S aureus infections commonly arise from asymptomatic colonisation, decolonisation is considered a key approach for their prevention. Current decolonisation procedures include antibiotic-based and antiseptic-based eradication of S aureus from the nose and skin. However, despite the widespread implementation and partial success of such measures, S aureus infection rates remain worrisome, and resistance to decolonisation agents is on the rise. In this Review we outline the epidemiology and mechanisms of S aureus colonisation, describe how colonisation underlies infection, and discuss current and novel approaches for S aureus decolonisation, with a focus on the latest findings on probiotic strategies and the intestinal S aureus colonisation site. ____________________________________________________ #biology #microorganism #laboratory #agar #fungi #biotech #microbzoo #virus #medicine #medical #student #microbial #instagram #biotech #university #researcher #research #chemist #germs #fungi