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Marine Algal Secondary Metabolites Are a Potential Pharmaceutical Resource for Human Society Developments
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Somasundaram Ambiga, Raja Suja Pandian, Lazarus Vijune Lawrence, Arjun Pandian, Ramu Arun Kumar, Bakrudeen Ali Ahmed Abdul
Proteases enzymes, commonly known as biological catalysts, are responsible for a wide range of biochemical processes. They’ve been used in a variety of fields, especially therapeutics. The properties of molecules produced from the marine differ from those of their terrestrial counterparts. Marine microbes (epibionts and endosymbionts), which are abundant in unique environments, produce a plethora of medically and industrially essential molecules. These microbes secrete enzymes with specific characteristics like pH, metal, heat and cryo-tolerance and so on. Proteases are enzymes that break down lengthy chains of proteins into smaller fragments. Endopeptidases and exopeptidases are the two large families of proteases depending on their method of action. Exopeptidases degrade terminal amino acid positions attached to polypeptide chains, while endopeptidases catalyze the breakdown of peptide bonds in the middle portion of polypeptide chains. A further way of classifying proteases is by their optimum pH, which might be neutral, acidic, or alkaline. In terms of the active centers involved, enzymes can be classed as cysteine proteases, metalloproteases, serine proteases and aspartyl proteases.
23S rRNA-Derived Small Ribosomal RNAs: Their Structure and Evolution with References to Plant Phylogeny
Published in S. K. Dutta, DNA Systematics, 2019
A plant cell has a more complex genetic organization than cells of other organisms. The plant genome is represented by three genetic compartments localized in the nucleus, mitochondria, and chloroplasts. Cytoplasmic ribosomes encoded by the nuclear genome are ribosomes of eukaryotic type and contain two low molecular weight rRNAs, 5.8S and 5S rRNA. Ribosomes of plant mitochondria and chloroplasts are quite close to those of bacteria; they contain 5S rRNA and are free of 5.8S rRNA.25,26 Chloroplast ribosomes also possess a component which is designated 4.5S rRNA; it has been observed thus far only in higher plants (see below). According to the widely accepted endosymbiotic hypothesis,27–30 chloroplasts and mitochondria are prokaryote-symbiont secondary intruders of a protoeukaryotic cell. This endosymbiosis, however, is very ancient; it must date back to the appearance of primary eukaryotic organisms. The organelle genome later evolved as the part of the eukaryotic total genetic system. A parallel analysis of macromolecule evolution from organelle and cytoplasm allows one to make more precise phylogenetic analyses and to specify the evolution of individual genetic compartments.
The Azolia-Anabaena Symbiosis
Published in Peter M. Gresshoff, Molecular Biology of Symbiotic Nitrogen Fixation, 2018
Robins et al.56 have observed that the surface of cells of A. azollae (isolated from Azolla filiculoides) was covered in a layer of hydrated mucilage. This mucilage was observed in the A. azollae cells adhering to plant cells in the cavity of the frond. The authors proposed that the cyanobacterial cells were held attached to the surface on which they were growing by the layer of hydrated mucilage which adhered to both the cell surfaces and a variety of support matrices. The mucilage, in the authors' opinion, allows a firmer, long-term attachment of the endosymbiont. Since the mucilage production occurred on inert surfaces, it seemed to be produced by the endophyte, and most probably the adhesion did not depend on specific interactions involving lectins as previously proposed.57,58
An antimicrobial metabolite n- hexadecenoic acid from marine sponge-associated bacteria Bacillus subtilis effectively inhibited biofilm forming multidrug-resistant P. aeruginosa
Published in Biofouling, 2023
Arya Sajayan, Amrudha Ravindran, Joseph Selvin, Prathiviraj Ragothaman, George Seghal Kiran
The ability of endosymbionts of Callyspongia diffusa to produce antibacterial molecules has already been reported (Gandhimathi et al. 2008; Kiran et al. 2018). In the present study, a total of 39 different bacterial strains were isolated from C. diffusa and screened for antimicrobial activity against MDR P. aeruginosa FP012. The occurrence of Bacillus species with antimicrobial potential in marine sponge endosymbiont systems has been reported previously (Pabel et al. 2003; Kiran et al. 2018). MSI38 showed a MIC of 31.33 ± 5.67 mg L−1 against P. aeruginosa FP012, which was lower than the value reported for bacteriocin produced by B. subtilis against S. epidermidis at 1.44 mg/mL and E. coli at 2.88 mg mL−1 (Sharma et al. 2018). MSI38 n-hexadecenoic acid was found to be bactericidal based on the MBC/MIC ratio. IIf the ratio MBC/MIC was less than 4, the effect was considered bactericidal; whereas, if the ratio MBC/MIC was greater than 4, the effect was termed bacteriostatic (Levison 2004; Thomas et al. 2012; Mogana et al. 2020).
Identification of Gut Bacteria such as Lactobacillus johnsonii that Disseminate to Systemic Tissues of Wild Type and MyD88–/– Mice
Published in Gut Microbes, 2022
Sreeram Udayan, Panagiota Stamou, Fiona Crispie, Ana Hickey, Alexandria N. Floyd, Chyi-Song Hsieh, Paul D. Cotter, Orla O’Sullivan, Silvia Melgar, Paul W. O’Toole, Rodney D. Newberry, Valerio Rossini, Ken Nally
Many of the bacteria that we recovered from systemic tissues, have been reported to have beneficial host immunomodulatory effects. L. johnsonii in particular has been reported to reduce proinflammatory responses in murine liver,32 restore normal levels of CD4+ and CD8+ T cells in spleen,33 and trigger differentiation of splenic CD4+ T cells into tumoricidal Th17 cells in cyclophosphamide treated tumor mice.34 Given that we have also found viable L. johnsonii residing in cells and tissues systemically it is tempting to speculate that gut symbionts, such as L. johnsonii, could also function as endosymbionts in order to exert their immunomodulatory effects. For the first time we show that, different bacterial members of the murine gut microbiota, predominantly L. johnsonii, can translocate from the GIT to systemic tissues in WT and MyD88−/− mice. Our stringent and validated culture-dependent approach will be beneficial to identify the cellular and molecular mechanisms underpinning the gut and systemic immunomodulatory effects of gut symbionts and pathobionts, their systemic dissemination, and their contribution to health and disease.
The relevance of studying insect–nematode interactions for human disease
Published in Pathogens and Global Health, 2022
Zorada Swart, Tuan A. Duong, Brenda D. Wingfield, Alisa Postma, Bernard Slippers
Wolbachia bacteria also colonize many insect species and other arthropods, either as mutualists or pathogens [33,34,60]. Wolbachia endosymbionts influence the host insect’s reproductive fitness and can increase the fertility of infected females or cause sterility in males [61]. Artificial infection of previously uninfected insects can be lethal or reduce the capability to vector certain pathogens [62–64]. The ability of Wolbachia to alter insect reproduction earns them a place in vector control and these bacteria are already being investigated for use against malaria, dengue fever, and lymphatic filariasis [65–67]. As in the case of insect vectors and nematode parasites, the molecular mechanisms underlying these interspecific interactions are in need of further investigation [33].