China
Africa
Explore chapters and articles related to this topic
Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
There are presently considered to be two distinct Prokaryotic Kingdoms: (1) True Bacteria (Eubacteria) and (2) Archaebacteria; both of which are distinct from a third Kingdom: Eucarya (i.e., the eucaryotes), that includes all plants, animals, fungi, ciliates, cellular slime molds, flagellates, and microsporidia. However, some disagreement exists about the taxonomy and spelling as some authors divide the Eucarya into four separate kingdoms: (3) Protista, which includes water molds, slime molds, protozoa, and primitive eukaryotic algae; (4) Fungi, which includes yeast, multicellular molds including some with macroscopic forms; (5) Plants, and (6) Animals. If the three kingdom taxonomy is adhered to, then the four eukaryote kingdoms would be Phyla or Divisions within Eucarya. Note that the Protista and Fungi are comprised primarily of microorganisms.
Transcriptionally Regulatory Sequences of Phylogenetic Significance
Published in S. K. Dutta, DNA Systematics, 2019
The sharing of common sequences between functionally related genes from prokaryotes and eukaryotes has also been shown. Heat shock genes produce proteins of an apparent molecular weight of 70,000 that are antigenically similar throughout eukaryotes, from man to yeast. Detailed sequence analysis of a major Drosophila heat shock gene, HSP 70, shows that it is 48% identical to a heat inducible gene, dnaK, from E. coli.8 It is interesting to note that such a sequence is also present in Methanosarcia barberi, an archaebacteria. One of the E. coli heat shock regulatory genes, htpr, as predicted from its cloned gene sequence, actually resembles the σ factor of E. coli polymerase.9
Structure and Evolution of the Small Blue Proteins
Published in René Lontie, Copper Proteins and Copper Enzymes, 1984
In bacterial phylogeny, based on ribosomal RNA sequences, the Az-containing genera Pseudomonas, Alcaligenes, and Paracoccus are found in three of the four branches of the purple photosynthetic bacteria.87 These constitute in turn one of the four major groupings of the eubacteria, one of the three kingdoms of living cells (the other two being the archaebacteria and the urkaryotes or ancestral eukaryotes). The origin of the Az’s would thus be located in an ancestral purple photosynthetic bacterium. The origin of the Pc’s would be expected to be found among the cyanobacteria, which form one of the other major groupings of the eubacteria. The relationship of the cyanobacteria to higher plant chloroplasts remains unclear, especially with regard to the Pc’s.103 These have so far only been isolated from heterocyst-forming filamentous cyanobacteria, while none of the investigated unicellular species contained the protein.103 Still it is the latter which are assumed to be the ancestors of the chloroplasts via an endosymbiotic relationship with a eukaryotic cell.104 The data are at present inconclusive. Fossil evidence suggests that the major cyanobacterial lines were established at least 3,000 million years ago.105 The common ancestor of the blue copper-containing proteins would then have existed before this date. It is clear that the blue proteins represent an ancient line of metalloproteins that later has evolved into a great diversity of forms participating both in the evolution of oxygen — in oxygenic photosynthesis — and in the reduction of oxygen for efficient energy production — in mitochondrial and bacterial redox chains — as well as in many other metabolic roles, only some of which are known. The relationships between these proteins are delineated in Figure 10.
Three-way interaction model with switching mechanism as an effective strategy for tracing functionally-related genes
Published in Expert Review of Proteomics, 2019
Nasibeh Khayer, Mehdi Mirzaie, Sayed-Amir Marashi, Mostafa Rezaei-Tavirani, Fatemeh Goshadrou
While there are numerous studies by 2WI approach so far [19–22], studies focusing on 3WI approach are limited. The main reason for such an unpopularity is presumably large number of possible interactions for more than two genes at the genome scale, which hampers the applicability of 3WI analysis [17]. In addition, it should be noted that so far all of the studies that considered on 3WIs have used eukaryotic datasets such as human [17,23], mouse [24] and yeast [11,13] gene expression data. Therefore, it is not yet known whether this model is applicable to prokaryotic data. However, because of the evolutionary relationships that exists between archaebacteria and eukaryotic organisms [25], the observation of 3WIs in the prokaryotic (and especially archaeal) gene expression data is not unexpected.
Targeting the GPI biosynthetic pathway
Published in Pathogens and Global Health, 2018
GPI anchor discovered in 1976 [1] is a complex glycolipid synthesized in the endoplasmic reticulum by a conserved pathway involving at least 19 gene products with a common core structure of EtNP-6Manα1-2Manα1-6Manα1-4GlcNα1-6myo-inositol-phospholipid [Figure 1] [2,3]. After its synthesis, GPI anchor is post-translationally transferred to the proteins carrying specific C-terminal GPI signal sequences (GPI-APs) in the endoplasmic reticulum. This is followed by their targeting to the cell membrane/cell wall through the secretory pathway. GPI-APs make up approximately 0.5% of cellular proteins in organisms as diverse as Saccharomyces cerevisiae, Caenorhabditis elegans and Plasmodium falciparum [4]. These are widely distributed in eukaryotes ranging from protozoans to mammals [5–7] and a few are reported even in some species of archaebacteria [4,8]. The GPI anchor as such and the GPI-APs play many vital and diverse roles in eukaryotes, owing to which GPI biosynthesis is either essential or important in eukaryotes [2,9,10]. Perhaps more noteworthy is the fact that GPI anchors and the GPI-APs have been used as virulence tools by pathogens especially protozoans and fungi to evade human immune response [11–14], and as such are the determining factors for various human diseases and disorders. Therein lies the great scope for specific targeting of the GPI pathway as there are species-specific differences in the GPI pathway among eukaryotes [Figure 2] which can be exploited for the development of antiprotozoan/antifungal drugs.
In vitro evaluation of archaeosome vehicles for transdermal vaccine delivery
Published in Journal of Liposome Research, 2018
Yimei Jia, Michael J. McCluskie, Dongling Zhang, Robert Monette, Umar Iqbal, Maria Moreno, Janelle Sauvageau, Dean Williams, Lise Deschatelets, Zygmunt J. Jakubek, Lakshmi Krishnan
A number of studies have indicated that archaeosome made of different archaebacteria species are surprisingly stable under various stresses (Patel et al.2000, Barbeau et al.2011, McCluskie et al.2017). Additonally, bipolar tetraether cardarchaeal exhibited unusual stability in terms of withholding their content at temperatures above 100 °C (McCluskie et al.2017). Therefore, it was not surprising that in our study M. smithii TPL archaeosomes showed the least leakage of incorporated OVA over 24 h. Likewise, if these archaeosomes are the most stable, it is not surprising that they are able to deliver antigen more effectively to depper cells layers.