China
Africa
Explore chapters and articles related to this topic
The Aedes Fauna: Different Aedes Species Inhabiting the Earth
Published in Jagriti Narang, Manika Khanuja, Small Bite, Big Threat, 2020
Annette Angel, Bennet Angel, Neelam Yadav, Jagriti Narang, Surender Singh Yadav, Vinod Joshi
Nad4 gene was used for identification of the species in Germany and Liguria (Pfitzner et al., 2018; Ballardini et al., 2019). A total of 62 proteins are enlisted in the NCBI database that includes COX 1 subunit, NAD 4, and β tubulin. Microbiota present in Aedes koreicus has been demonstrated by Alfano and his team (2019) using 16srRNA for characterizing purposes. V3 and V4 regions of the 16s rDNA was used for sequencing of microbiota. The results showed presence of Proteobacteria species in the observed adults (84%) and larvae (66%), specifically Gammaproteobacteria followed by Bacteroidetesand Actinobacteria in the water, larvae, and pupae collected and Alphaproteobacteria in the adult forms collected. Firmicutes were also observed in all, except water samples. Pseudomonas, Gilliamella, Dyella and Pantoea, and Enterobacteriacea family were also seen in adults. When the trend of microbial fauna in the water samples and the larval and adult forms were compared, it was seen that only 10% of those found in water reached the larval gut and established themselves there, and as the life cycle continued, only few microbial fauna were able to invade the pupal and then the adult system (Alfani et al., 2019).
Structure, Function and Evolutionary Aspects of Mitochondria
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Puja Agarwal, Mehali Mitra, Sujit Roy
It is hypothesised that at least one thousand million years ago, the ancestor of modern bacteria collided with an ancestral eukaryote and evolved to form mitochondria. Initially the alphaproteobacteria contained all the genes necessary for its survival. But gradually with the establishment of the organelle genome modification of the endosymbiont took place. According to sequence homology, mitochondria and chloroplast evolved from free living eubacteria via symbiosis but by different pathways (Margulis, 1970). Mitochondria share its origin with purple bacteria while chloroplast shares it with cyanobacteria. Studies of mitochondrial DNA sequences and its expression confirm that mitochondria are direct descendants of alpha-division of the proteobacterial ancestors. Members of Rickettsial subdivision, a group of obligate parasites that includes the genera Anaplasma, Ehrlichia and Rickettsia are closest eubacterial relative of mitochondria. Phylogenetic reconstructions and distance measurements carried out on the basis of sequences of cytochrome c oxidase and cytochrome b posits that mitochondria diverged from bacteria between 1.5 and 2.0 billion years ago (Sicheritz-Ponten et al., 1998). Accordingly, this supports the idea that oxidative respiratory system that was introduced into the eukaryotic lineages was an endosymbiotic alphaproteobacterium (Gray and Doolittle, 1982; Gray et al., 1989, Gray, 1999; Andersson et al., 1998; Sicheritz-Ponten et al., 1998).
Brucella: A Foodborne Pathogen
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Members of the genus Brucella are small (0.4–3 um), gram-negative, cocco-bacillary organisms within the bacterial class Alphaproteobacteria that exist as intracellular pathogens in mammalian hosts. Most Brucella species are obligate pathogens in that they do not occur as commensals and are not found free-living in the environment. However, a recently identified Brucella species in voles, B. microti, may have genetic differences that support a free-living as compared to a host-associated lifestyle.9 Although classic species of Brucella may be temporarily recovered from the environment of infected animals, environmental persistence is generally not believed to be of epidemiologic importance. Because direct or close contact is often required for transmission, maintenance of brucellosis in animal populations depends on continual infection of susceptible hosts. As humans are essentially dead-end hosts, infection in humans requires exposure to brucellosis from animal reservoirs.
Epibiotic bacteria on the carapace of hawksbill and green sea turtles
Published in Biofouling, 2023
Javad Loghmannia, Ali Nasrolahi, Sergey Dobretsov
At the class level, a total of 66 classes were identified in all samples. The major bacterial classes with a relative abundance > 0.9% were composed of 21 classes (Figure 4). The classes Gammaproteobacteria (16–40%) and Alphaproteobacteria (27–32%) dominated all samples. In addition, Deltaproteobacteria (6–10%) and Actinobacteria (2–11%) were relatively abundant (Figure 4). Alphaproteobacteria (27–32%) and Gammaproteobacteria (18–19%) dominated biofilms on hawkheads, while Deinococci (2–1.7%) and Planctomycetia (2%) were less abundant. The class Holophagae (2%) was present only on hawksbill turtles from Ommolgorm (HO, Figure 4). Biofilms on green sea turtles from Dokoohak (GD) were dominated by Gammaproteobacteria (40%), whereas biofilms on green sea turtles from Shibderaz (GS) were dominated by Alphaproteobacteria (25%). The most abundant bacterial class in all samples of stones was Alphaproteobacteria (28–32%) and the second most abundant class was Gammaproteobacteria (16–22%), while Verrucomicrobiae was the least abundant (1%). The classes Dehalococcoidia and Gemmatimonadetes occurred only in biofilms on stones from Ommolgorm (Figure 4).
Periodontitis pathogen Porphyromonas gingivalis promotes pancreatic tumorigenesis via neutrophil elastase from tumor-associated neutrophils
Published in Gut Microbes, 2022
Qin Tan, Xiao Ma, Bing Yang, Ye Liu, Yibin Xie, Xijun Wang, Wei Yuan, Jie Ma
To explore the human intrapancreatic microbiome composition, we performed 16s Ribosomal RNA Gene Sequencing (16s rRNA) on resected cancer tissue and matched normal adjacent tissues (NAT), employed from 20 pancreatic patients (Clinical characteristics are shown in Sup Table S1). Refraction curves of each sample were found approached saturation, indicating the adequate sequencing depth and the abundant presence of bacteria (Sup Figure S1a). We first sought to determine the landscape of the microbial composition between PC tumor and their NAT, which presented a similar community at various taxonomic levels (Figure 1a, Sup Figure S1b). 150 distinct classes were detected in human PC tumor and NAT. Gammaproteobacteria (31.2%), Bacteroidia (14.1%), Clostridia (12.8%), Bacilli (12.2%), Alphaproteobacteria (11.7%) were most prevalent in all PC specimens (Figure 1b, Sup Table S2). Although the overall microbial composition was relatively similar, we explored the differential taxonomic prevalence in tumors and their NAT. By visualizing the operational taxonomic units (OTUs) abundance at the genus level with comparison heatmap, 44 genera were found significantly different between PC and NAT (p<0.05, Figure 1c and Sup Table S3).
The effect of different carbon sources on biofouling in membrane fouling simulators: microbial community and implications
Published in Biofouling, 2022
Johny Cabrera, Hao-yu Guo, Jia-long Yao, Xiao-mao Wang
The relative abundance of bacteria at the phylum and class levels is shown in Figure 10. The ten most abundant taxa were selected for this analysis since they include most of the OTUs identified (Yao et al. 2020). At the phylum level, the most abundant taxa identified was proteobacteria, followed by Bacteroidetes. At the phylum level, more than 95% of the bacteria in the samples analyzed were proteobacteria when a single carbon source (acetate, glucose, or fructose) was used. In the control samples and samples with more than a single carbon source, the abundance of the bacterial community increased, while proteobacteria was still the most abundant at more than 60%. Bacteroides and other phylum were present in the samples. Several studies have also shown proteobacteria to be the most abundant phylum in the biofilm on membranes used for water treatment (Zodrow et al. 2014; Sánchez 2018; Yu et al. 2018; Vries et al. 2019; Yao et al. 2020), especially those belonging to the alpha, beta and gamma classes (Ayache et al. 2013; Belila et al. 2016; Nagaraj et al. 2017). At the class level, the most abundant class in the current experiments was gammaproteobacteria, followed by alphaproteobacteria. In most studies analyzing the microbial abundance of RO membranes, the alphaproteobacteria class is the most abundant, although there are a few cases where gammaproteobacteria have been reported to be the dominant class (Nagaraj et al. 2017; Sánchez 2018).