China
Africa
Explore chapters and articles related to this topic
Genetic Engineering of Clostridial Strains for Cancer Therapy
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Maria Zygouropoulou, Aleksandra Kubiak, Adam V. Patterson, Nigel P. Minton
CPG2 expression and secretion have been attempted twice in C. sporogenes using a codon-optimized version of the CPG2 gene from Variovorax paradoxus. The native signal peptide of the protein was substituted for the eglA signal peptide from C. saccharobutylicum, which would be more suitable for use in a gram-positive organism. Unfortunately, in both instances, there was almost no CPG2 activity detected in the culture supernatants, presumably due to proteolytic cleavage of the enzyme as a result of proteases secreted by C. sporogenes. CPG2 activity was higher in the soluble fraction of cell lysates, indicating that protein export might have been defective [42, 43]. In view of the above shortcomings, the implementation of CPG2 in CDEPT has not been pursued further.
Quorum sensing pathways in Gram-positive and -negative bacteria: potential of their interruption in abating drug resistance
Published in Journal of Chemotherapy, 2019
Shafiul Haque, Dinesh K. Yadav, Shekhar C. Bisht, Neelam Yadav, Vineeta Singh, Kashyap Kumar Dubey, Arshad Jawed, Mohd Wahid, Sajad Ahmad Dar
QS signal degradation in Gram-negative bacteria is mostly caused by various AHL degrading enzymes which are categorized into two classes: AHL acylases and AHL lactonases.177 Enzymatic activity of AHL acylases and lactonases involves the cleavage of amide linkage of AHLs and inactivation of lactone ring, respectively.178 Syntheses of acylases were first reported in Variovorax paradoxus178 which degrades the AHL through alkaline hydrolysis of acyl group as an energy source. Xu et al.179 reported a porcine acylase I showing hydrolytic activity for both, the C4-HSL and C8-HSL. An enzyme with potent AHL lactonase activity has been isolated from B. thuringiensis, which displays the ability to attenuate pathogenicity of Erwinia carotova.180
Graphene oxide influence in soil bacteria is dose dependent and changes at osmotic stress: growth variation, oxidative damage, antioxidant response, and plant growth promotion traits of a Rhizobium strain
Published in Nanotoxicology, 2022
Tiago Lopes, Paulo Cardoso, Diana Matos, Ricardo Rocha, Adília Pires, Paula Marques, Etelvina Figueira
The first hypothesis that GO nanosheets could influence bacterial growth under osmotic stress was confirmed. Drought has several impacts on soil properties, being water potential the most relevant. With the decrease of water potential, nutrient uptake is hampered, limiting bacterial activity, decreasing carbon and nitrogen mineralization, and affecting soil properties (Ilstedt, Nordgren, and Malmer 2000; Pulleman and Tietema 1999). Exposure of bacteria to water potentials lower than −1 MPa may induce alterations in several cellular functions, being −0.5 to −0.8 MPa the best range for bacteria growth (Siddiqi and Husen 2017; Wilson and Griffin 1975; Chowdhury, Marschner, and Burns 2011). Differences among bacteria genera were reported with Rhizobium, Erwinia, Xanthomonas, Flavobacterium, Pseudomonas, Paenibacillus, Variovorax and Achromobacter being able to tolerate −4 MPa (Harris 1981; Sá, Cardoso, and Figueira 2019). In our study the addition of 10% PEG to the medium lowered the water potential −4.1 MPa, inducing a decrease in the growth of E20-8 by around 50%. Sá, Cardoso, and Figueira (2019) classified as medium tolerant those bacteria capable to tolerate 10% PEG, highlighting the ability of bacteria with this osmotolerance level to survive and grow in environments with water restriction. Other studies also evidenced the inhibitory effect of osmotic stress on different plant growth-promoting bacteria (Fierer and Schimel 2002; Chang et al. 2007; Patel, Jinal, and Amaresan 2017; Benabdellah et al. 2011; Omara and Elbagory 2018). Omara and Elbagory (2018) reported the inhibitory effect of a range of PEG concentrations (0–40%) on different PGPR, and only the most tolerant bacteria (Bacillus and Pseudomonas) were able to grow at the highest PEG concentrations. Abdel-Salam et al. (2010) and Uma, Paramasivam, and Sangeetha (2013) reported that various bradyrhizobial isolates did not respond positively to the decrease of osmotic potential induced by PEG (0–0%), pointing to the possible unknown consequences for their abilities to promote pant growth and other services they provide.
Citizen-science based study of the oral microbiome in Cystic fibrosis and matched controls reveals major differences in diversity and abundance of bacterial and fungal species
Published in Journal of Oral Microbiology, 2021
Jesse R. Willis, Ester Saus, Susana Iraola-Guzmán, Elena Cabello-Yeves, Ewa Ksiezopolska, Luca Cozzuto, Luis A. Bejarano, Nuria Andreu-Somavilla, Miriam Alloza-Trabado, Andrea Blanco, Anna Puig-Sola, Elisabetta Broglio, Carlo Carolis, Julia Ponomarenko, Jochen Hecht, Toni Gabaldón
Among the matched control samples, the co-occurrence networks primarily support our speculations on the underlying mechanisms that might lead to lower incidence of periodontitis and greater damage to enamel in CF patients as compared to non-CF controls. Prevotella and Veillonella are among the four most abundant genera in our dataset and were significantly associated in 92 of the matched control networks. Prevotella, Veillonella, and Solobacterium are all periodontal pathogens [98,145,146], and Prevotella melaninogenica and Solobacterium moorei, whose genera were significantly associated in 61 matched control networks, utilize cysteine to produce hydrogen sulfide (H2S), resulting in halitosis [147,148]. Cysteine is a precursor to glutathione [149], a peptide that helps to protect the lung from oxidants, and is found at lower levels in the lungs of CF patients [150], and acetylcysteine, a prodrug to cysteine, has been used to improve lung function in CF patients [151]. So perhaps there is a connection between greater overall availability of cysteine in non-CF individuals and the production of H2S by organisms like P. melaninogenica and S. moorei. Veillonella species also produce volatile sulfur compounds that cause halitosis [146]. Streptococcus and Gemella are among the most abundant taxa present in the oral microbiome (Figure 1(a)) so it is not strange that they would have a significant association in 92 of the 100 control networks, though it is curious that they did not in the CF network. As mentioned above, Streptococcus was significantly more abundant in our CF samples and has been associated with CF lung infections [21,68–71], and Gemella may play a role in exacerbations of CF infections [152]. Nonetheless, they both have some involvement in periodontitis as well [130,131,153,154], and species of Streptococcus in particular make up the ‘yellow-complex’ of periodontal pathogens, which are early colonizers in that disease [145,155]. Somewhat unexpected associations also occurred exclusively in the matched control networks between Gemella and Granulicatella (occurs in 72 of the 100 matched control networks), and between Rothia and Granulicatella (55 of the 100 control networks), as Granulicatella has also been associated with CF [73,156,157] and caries due to its acidogenic nature [158]. The significant associations seen exclusively in our matched control networks involving Ralstonia and Variovorax [159–162], Atopobium [163,164], Bradyrhizobium [165], Hyphomicrobium [166], Actinomyces [167], Stomatobaculum [168], Rothia [102,163,164], Clostridiales Family_XIII [101], Parvimonas [97,101,169], Treponema [97,101], Filifactor [101,170,171], and Dialister [172,173], all relate to organisms implicated in periodontitis.