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Structure, Function and Evolutionary Aspects of Mitochondria
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Puja Agarwal, Mehali Mitra, Sujit Roy
Phylogenetic studies proved a robust connection between mitochondria and Rickettsiales. Both Rickettsia and mitochondria depends on pyruvate for ATP production and both contains a similar cohort of proteins involved in the pyruvate dehydrogenase complex, the TCA cycle, the respiratory chain complex, and the ATP synthase complex. However, ATP transport is somewhat different in these two systems (Fig. 7). Definitive genome sequencing and data defining mitochondrial proteome of yeast identified 50 mitochondrial proteins that are closely related to alphaproteobacteria. This supports the identification of alphaproteobacteria as ancestor of mitochondria (Degli Esposti et al., 2016). Functional profiling of mitochondrial protein in alphaproteobacteria and eukaryotic homologue explains that bacterial homologues seem to be mainly involved in energy metabolism and translation. In contrast, the eukaryotic proteins participate in transport and regulatory functions. The proteins contributed by the alpha-proteobacteria to the eukaryotes are encoded in both the nuclear and mitochondrial genomes of serving direct and indirect roles in aerobic respiration (Gabaldon and Huynen, 2007; Wang and Wu, 2014).
Rickettsia spp.
Published in Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward, Case Studies in Infectious Disease, 2010
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward
The patient has a rickettsial infection. The taxonomy and nomenclature of the Rickettsiaceae have undergone a major revision based upon 16S rRNA sequences. Currently the Rickettsiales contain the Rickettsia, Orientia, Ehrlichia, Anaplasma, Wolbachia, and Neorickettsia. Coxiella burnetti is now included in the γ-proteobacteria along with Legionella and Francisella. Frequently Rickettsia are given species names relating to their original geographic location. There are many species of Rickettsia found in nature, only some of which have been linked to illness (Table 1) and present clinically as spotted fevers or typhus (see later).
Altered composition of the oral microbiome in integrin beta 6-deficient mouse
Published in Journal of Oral Microbiology, 2022
Osamu Uehara, Jiarui Bi, Deshu Zhuang, Leeni Koivisto, Yoshihiro Abiko, Lari Häkkinen, Hannu Larjava
Next, we used the QIIME 2 database to analyze the genus-level alterations in the bacterial composition between the Itgb6−/− and WT mice at two different ages. All 24 samples were sequenced using MiSeq, and 7,542,554 total sequences were amplified, ranging from a minimum of 91,349 to a maximum of 409,155 sequences per sample, with a mean of 314,273 sequences per sample. QIIME2 detected a total of 86 different bacterial genera. The oral microbial composition between each individual mouse in different groups was remarkably similar (Figure 5a) with the phylum Proteobacteria dominating the samples at 70–90% in all samples (Figure 5). At the family level, Pasteurellaceae was the dominating family, followed by Streptococcaceae (Figure 5). Members of the Streptococcaceae family, considered early colonizers in the dental plaque biofilm [25], showed little differences among the four mouse groups (Figure 5). Supporting the observed differences from the PCoA analyses, the bacterial composition at the genus level showed differences among the four mouse groups (Figure 5). Interestingly, an unidentified bacterial genus from Rickettsiales was increased in 6-month-old WT mice but decreased in 6-month-old Itgb6−/− mice (Figure 5). The Lactobacillus from Lactobacillaceae family had higher abundance in 3-month-old WT mice compared to others (Figure 5).
Scrub typhus and antibiotic-resistant Orientia tsutsugamushi
Published in Expert Review of Anti-infective Therapy, 2021
Chin-Te Lu, Lih-Shinn Wang, Po-Ren Hsueh
The earliest clinical reports of suspected scrub typhus can be traced back to the Chinese medical manual, ‘Zhouhofang,’ by Hong Ge in 313 BCE. The causative agent of scrub typhus, Orientia tsutsugamushi, is a gram-negative obligate intracellular rickettsiae [1]. According to the World Health Organization, ‘scrub typhus is probably one of the most underdiagnosed and under-reported febrile illnesses requiring hospitalization’ [2]. The agents of the order Rickettsiales are transmitted to humans via the bite or contamination of mucous membranes or lesions by ectoparasites or arthropods, such as hard and soft ticks, fleas, mosquitoes, mites, lice, and fleas [3–5]. In the past, cases of scrub typhus were primarily reported in Southeast and East Asia and the Pacific Islands, in an area referred to as the ‘Tsutsugamushi Triangle’; however, emerging reports of Orientia species and clinical cases from other regions, such as India, Africa, Europe, and the western coast of South America, suggest a much wider global distribution across tropical to subtropical regions [6–8]. This review summarizes the ecology, epidemiology, pathogenesis, clinical manifestations, laboratory diagnosis, and treatment of scrub typhus and discusses the role of antibiotic resistance of O. tsutsugamushi in therapy failure.
Emerging and threatening vector-borne zoonoses in the world and in Europe: a brief update
Published in Pathogens and Global Health, 2019
Bacterial order Rickettsiales causes wide range of related diseases spread by ticks, fleas, chiggers and lice. Spreading abilities, morbidity and mortality rates of Rickettsiales are high. Typhus fever caused by Rickettsia prowazekii was classified as the category B on the list of bioterrorism agents [81]. The most common rickettsiosis in Europe is Mediterranean spotted fever caused by Rickettsia conorii. Even though the disease had been endemic to Southern Italy for many years [82], it has been spreading recently [83]. This infection may represent a severe threat, as its mortality rate is about 32% [84]. Anaplasmosis caused by Anaplasma phagophytophila has also a strongly increasing and widespread occurrence in Europe [85,86]. Recently, new human rickettsial infections have been recognized in Europe [82,87]. In general, rickettsioses occurrence increases in northern countries, which had been traditionally Rickettsia free [88]. It is supposed that this increasing occurrence is associated with the rise of temperature and decreasing number of frosty days [83,89,90]. Several rickettsial vaccines were developed; however, they were difficult, expensive and very hazardous to produce [91]. There is still no approved vaccine available yet [92].