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Streptomyces: A Potential Source of Natural Antimicrobial Drug Leads
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Mahmoud A. Elfaky, Hanaa Nasr, Ilham Touiss, Mohamed L. Ashour
In the early 1940s, Waksman and Henrici first described the genus Streptomyces (Williams et al. 1983). It was included in the family Streptomycetaceae (Arai 1997) based on physiological and morphological characteristics. Furthermore, some other features, such as the cell wall chemical composition, including the phospholipids/peptidoglycan type, fatty acid chains and the 16S rRNA sequence, are very useful in the taxonomy of this genus (Kämpfer et al. 2008). The genus Streptomyces represents the only member of the family Streptomycetaceae that belongs to Actinobacteria phylum and is classified in Actinomycetales order placed in the class Actinobacteria (Anderson and Wellington 2001). However, Streptomyces is among the richest taxonomic components of known actinomycetes in terms of the number of discovered species (Bhattacharyya et al. 1998), with more than 500 species producing approximately two thirds of the known natural antibiotics (Mohanraj and Sekar 2013). Streptomyces are aerobic, Gram-positive, but not acid-fast bacteria that are also characterized by high guanine/cytosine content (> 70%) (Reza Dehnad et al. 2010) and can grow in different environments (Maleki et al. 2013).
Quantitative insights into effects of intrapartum antibiotics and birth mode on infant gut microbiota in relation to well-being during the first year of life
Published in Gut Microbes, 2022
Roosa Jokela, Katri Korpela, Ching Jian, Evgenia Dikareva, Anne Nikkonen, Terhi Saisto, Kirsi Skogberg, Willem M. de Vos, Kaija-Leena Kolho, Anne Salonen
We compared the birth modes while controlling for IP antibiotic exposure, including only cephalosporin-exposed CS and VD, to understand the effect of birth mode independently of antibiotic treatment, and vice versa (including only VD infants with different IP exposures) (Supplementary Figures 6, 7). Several bacterial families differed in absolute abundance between the VD-cep and CS-cep groups. In the CS-cep group, we observed enrichment of Verrucomicrobiaceae (3.8-fold difference, P < .001 at 6 weeks), Bifidobacteriaceae (18- and 12-fold differences, P < .05 at 4 and 12 weeks, respectively), Streptomycetaceae (7.0- and 62-fold differences, P < .001 at 4 weeks and 9 months), Lactobacillaceae (8.3- and 12-fold differences, P < .05 at 12 weeks and 9 months), Bacillaceae (3.8- and 8.5-fold differences, P < .001 at 6 weeks and 6 months), Peptostreptococcaceae (fold change range 7.5–5900, P < .01 at 4 and 12 weeks and 6 months), Lachnospiraceae (20- and 99-fold differences, P < .01 at 12 weeks and 6 months), Clostridiaceae (23-fold difference, P < .001 at 4 weeks), and Christensenellaceae (210-fold difference, P < .001 at 6 months). In contrast, Bacteroidaceae was reduced in CS-cep in comparison to VD-cep during weeks 4–12 (fold change 0.07, P < .01 at 6 weeks).
Integrated fecal microbiome–metabolome signatures reflect stress and serotonin metabolism in irritable bowel syndrome
Published in Gut Microbes, 2022
Zlatan Mujagic, Melpomeni Kasapi, Daisy MAE Jonkers, Isabel Garcia-Perez, Lisa Vork, Zsa Zsa R.M. Weerts, Jose Ivan Serrano-Contreras, Alexandra Zhernakova, Alexander Kurilshikov, Jamie Scotcher, Elaine Holmes, Cisca Wijmenga, Daniel Keszthelyi, Jeremy K Nicholson, Joram M Posma, Ad AM Masclee
A lower microbial alpha biodiversity is considered less beneficial for human health26 and has previously been shown in IBS;12,27,28 here, we again find it was decreased in IBS patients. However, other than microbiota composition, different gut microbes also frequently share similar metabolic capacities. Despite temporal differences in microbiota composition, the microbiome’s metabolic function has been shown to be quite stable over time,29 indicating that microbial metabolic function may be superior to microbial composition when studying the relationship between the microbiome and pathophysiology of disorders.26 When considering the most pronounced differences in the combined microbiome–metabolome analysis between IBS and HC in the current study, we found relevant indications for altered microbiota–host interactions. There was an increased relative abundance of Streptomycetaceae in IBS, a family in the phylum of Actinobacteria. The members in this family are known for their ability to produce important secondary metabolites in the arginine and BCAA-pathways.30 BCAA valine and isoleucine, both increased in fecal water of IBS, can serve as a substrate for valine N-monooxygenase, found in some species within the Mycobacteriaceae family, which were also increased in IBS. Previously, both these bacterial families were shown to be increased in oral mucosa of IBS patients and were associated with visceral sensitivity.31 Proton pump inhibitors (PPI), frequently used by IBS patients, can alter the fecal microbiome by increasing abundances of oropharyngeal microbes.32 In the present study, medication use, including PPI, was taken into account, and none of the identified clusters of IBS patients based on the microbiome–metabolome data were significantly associated with PPI use.
Nanotoxicity of engineered nanomaterials (ENMs) to environmentally relevant beneficial soil bacteria – a critical review
Published in Nanotoxicology, 2019
Ricky W. Lewis, Paul M. Bertsch, David H. McNear
Ge et al. (2011) found soils amended with 10.5, 21, or 42 mmol kg−1 of TiO2 ENMs or 8, 15, or 31 mmol kg−1 ZnO ENMs had decreased substrate-induced respiration (SIR) (up to 13%) and extractable DNA (up to 70%). At 15 and 60 d of exposure, extractable DNA reductions were concentration dependent, but were linear for TiO2 ENMs, and exponential for ZnO ENMs. Both particle types were found to result in shifts in microbial community structure, but the impact of ZnO ENMs was much more pronounced. Pyrosequencing revealed that ZnO and TiO2 led to a reduction in Rhizobiales, Bradyrhizobiaceae, Bradyrhizobium, and Methylbacteriaceae while increases were observed for Sphingomonadaceae, Streptomycetaceae, and Streptomyces (Ge et al. 2012). Interestingly, others have noted that copper and zinc nanoparticles decreased the abundance of Sphingomonadales and Flavobacteriales abundance (Collins et al. 2012). Nogueira et al. (2012) also found shifts in soil microbial community structure in response to TiO2 ENMs or Au nanorods. A study examining the effects of soil properties on TiO2 ENM toxicity found only one of six tested soils had decreased SIR (a soil with silty clay texture and high organic matter) (Simonin et al. 2015). Shifts in microbial community structure resulting from TiO2 ENMs exposure were also found to be more pronounced as soil moisture decreased, and may occur even though there are no changes in organic matter content, total N or C, C/N ratios, or bioavailable C (Ge et al. 2013). Soil amendment with biosolids containing mixtures of ENMs (Ag, Zn, and Ti) led to unique shifts in microbial community structure compared with bulk/dissolved metal controls; where ENM treatment yielded significant reductions in most microbial groups as assessed via phospholipid fatty acid analysis (PLFA) analysis compared with metal free controls (Judy, McNear, et al. 2015). These results, along with those discussed in the previous section, show that a variety of ENMs can influence soil microbial communities which can be influenced by soil and ENM type.