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Gardnerella is a genus of Gram-variable-staining facultative anaerobic bacteria of which Gardnerella vaginalis is the only species. The organisms are small non-spore-forming, nonmotile coccobacilli.
Listeria monocytogenes is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the host's cells and is one of the most virulent foodborne pathogens: 20 to 30% of foodborne listeriosis infections in high-risk individuals may be fatal. Responsible for an estimated 1,600 illnesses and 260 deaths in the United States annually, listeriosis ranks third in total number of deaths among foodborne bacterial pathogens, with fatality rates exceeding even Salmonella spp. and Clostridium botulinum. In the European Union, listeriosis follows an upward trend that began in 2008, causing 2,161 confirmed cases and 210 reported deaths in 2014, 16% more than in 2013. Listeriosis mortality rates are also higher in the EU than for other foodborne pathogens.
Listeria is a genus of bacteria that acts as an intracellular parasite in mammals. Until 1992, 10 species were known, each containing two subspecies. By 2020, 21 species had been identified. The genus received its current name, after the British pioneer of sterile surgery Joseph Lister, in 1940. Listeria species are Gram-positive, rod-shaped, and facultatively anaerobic, and do not produce endospores. The major human pathogen in the genus Listeria is L. monocytogenes. It is usually the causative agent of the relatively rare bacterial disease listeriosis, an infection caused by eating food contaminated with the bacteria. Listeriosis can cause serious illness in pregnant women, newborns, adults with weakened immune systems and the elderly, and may cause gastroenteritis in others who have been severely infected.
Ectopic is a word used with a prefix, ecto, meaning “out of place.” Ectopic expression is an abnormal gene expression in a cell type, tissue type, or developmental stage in which the gene is not usually expressed. The term ectopic expression is predominately used in studies using metazoans, especially in Drosophila melanogaster for research purposes.
Shewanella is the sole genus included in the marine bacteria family Shewanellaceae. Some species within it were formerly classed as Alteromonas. Shewanella consists of facultatively anaerobic Gram-negative rods, most of which are found in extreme aquatic habitats where the temperature is very low and the pressure is very high. Shewanella bacteria are a normal component of the surface flora of fish and are implicated in fish spoilage.
The OmrA-B RNA gene family is a pair of homologous OmpR-regulated small non-coding RNA that was discovered in E. coli during two large-scale screens. OmrA-B is highly abundant in stationary phase, but low levels could be detected in exponentially growing cells as well. RygB is adjacent to RygA a closely related RNA. These RNAs bind to the Hfq protein and regulate gene expression by antisense binding. They negatively regulate the expression of several genes encoding outer membrane proteins, including cirA, CsgD, fecA, fepA and ompT by binding in the vicinity of the Shine-Dalgarno sequence, suggesting the control of these targets is dependent on Hfq protein and RNase E. Taken together, these data suggest that OmrA-B participates in the regulation of outer membrane composition, responding to environmental conditions.
In molecular biology the ArcZ RNA is a small non-coding RNA (ncRNA). It is the functional product of a gene which is not translated into protein. ArcZ is an Hfq binding RNA that functions as an antisense regulator of a number of protein coding genes.
An Hfq binding sRNA is an sRNA that binds the bacterial RNA binding protein called Hfq. A number of bacterial small RNAs which have been shown to bind to Hfq have been characterised . Many of these RNAs share a similar structure composed of three stem-loops. Several studies have expanded this list, and experimentally validated a total of 64 Hfq binding sRNA in Salmonella Typhimurium. A transcriptome wide study on Hfq binding sites in Salmonella mapped 126 Hfq binding sites within sRNAs. Genomic SELEX has been used to show that Hfq binding RNAs are enriched in the sequence motif 5′-AAYAAYAA-3′. Genome-wide study identified 40 candidate Hfq-dependent sRNAs in plant pathogen Erwinia amylovora. 12 of them were confirmed by Northern blot.
Bacterial small RNAs (sRNA) are small RNAs produced by bacteria; they are 50- to 500-nucleotide non-coding RNA molecules, highly structured and containing several stem-loops. Numerous sRNAs have been identified using both computational analysis and laboratory-based techniques such as Northern blotting, microarrays and RNA-Seq in a number of bacterial species including Escherichia coli, the model pathogen Salmonella, the nitrogen-fixing alphaproteobacterium Sinorhizobium meliloti, marine cyanobacteria, Francisella tularensis, Streptococcus pyogenes, the pathogen Staphylococcus aureus, and the plant pathogen Xanthomonas oryzae pathovar oryzae. Bacterial sRNAs affect how genes are expressed within bacterial cells via interaction with mRNA or protein, and thus can affect a variety of bacterial functions like metabolism, virulence, environmental stress response, and structure.
Solemya velum, the Atlantic awning clam, is a species of marine bivalve mollusc in the family Solemyidae, the awning clams. This species is found along the eastern coast of North America, from Nova Scotia to Florida.
Clostridium sticklandii is an anaerobic, motile, gram-positive bacterium. It was first isolated in 1954 from the black mud of the San Francisco Bay Area by T.C. Stadtman, who also named the species. Cl. sticklandii is not pathogenic in humans.
An overlapping gene is a gene whose expressible nucleotide sequence partially overlaps with the expressible nucleotide sequence of another gene. In this way, a nucleotide sequence may make a contribution to the function of one or more gene products. Overprinting refers to a type of overlap in which all or part of the sequence of one gene is read in an alternate reading frame from another gene at the same locus. Overprinting has been hypothesized as a mechanism for de novo emergence of new genes from existing sequences, either older genes or previously non-coding regions of the genome. Overprinted genes are particularly common features of the genomic organization of viruses, likely to greatly increase the number of potential expressible genes from a small set of viral genetic information.
Geobacter sulfurreducens is a gram-negative metal and sulphur-reducing proteobacterium. It is rod-shaped, obligately anaerobic, non-fermentative, has flagellum and type four pili, and is closely related to Geobacter metallireducens. Geobacter sulfurreducens is an anaerobic species of bacteria that comes from the family of bacteria called Geobacteraceae. Under the genus of Geobacter, G. sulfurreducens is one out of twenty different species. The Geobacter genus was discovered by Dr. Derek R. Lovley in 1987. G. sulfurreducens was first isolated in Norman, Oklahoma, USA from materials found around the surface of a contaminated ditch.
Brucella microti is a species of bacteria first isolated from the common vole, Microtus arvalis. Its genome has been sequenced. It is Gram-negative, non-motile, non-spore-forming, and coccoid, with the type strain CCM 4915T. It is pathogenic.
Pelobacter carbinolicus is a species of bacteria that ferments 2,3-butanediol and acetoin. It is Gram-negative, strictly anaerobic and non-spore-forming. Gra Bd 1 is the type strain. Its genome has been sequenced.
Listeria marthii is a species of bacteria. It is a Gram-positive, motile, facultatively anaerobic, non-spore-forming bacillus. It is non-pathogenic, and non-hemolytic. The species was first isolated from Finger Lakes National Forest in New York. It is named after Elmer H. Marth, a researcher of L. monocytogenes, and was first published in 2010. L. marthii was the first new species of Listeria proposed since 1985.
Geobacter bemidjiensis is a Fe(III)-reducing bacteria. It is Gram-negative, slightly curved rod-shaped and is motile via means of monotrichous flagella. Its type strain is BemT.
Geobacter psychrophilus is a Fe(III)-reducing bacterium. It is Gram-negative, slightly curved, rod-shaped and motile via means of monotrichous flagella. Its type strain is P35T.
Several small RNAs have been identified in Francisella tularensis, pathogenic bacterium that causes the disease tularaemia. Very little is known about Francisella's regulatory networks that allow this bacterium to survive in many environments.
Fungal genomes are among the smallest genomes of eukaryotes. The sizes of fungal genomes range from less than 10 Mbp to hundreds of Mbp. The average genome size is approximately 37 Mbp in Ascomycota, 47 Mbp in Basidiomycota and 75 Mbp in Oomycota. The sizes and gene numbers of the smallest genomes of free-living fungi such as those of Wallemia ichthyophaga, Wallemia mellicola or Malassezia restricta are comparable to bacterial genomes. The genome of the extensively researched yeast Saccharomyces cerevisiae contains approximately 12 Mbp and was the first completely sequenced eukaryotic genome. Due to their compact size fungal genomes can be sequenced with less resources than most other eukaryotic genomes and are thus important models for research. Some fungi exist as stable haploid, diploid, or polyploid cells, others change ploidy in response to environmental conditions and aneuploidy is also observed in novel environments or during periods of stress.
References
- ↑ Leclercq, A.; Clermont, D.; Bizet, C.; Grimont, P. A. D.; Le Fleche-Mateos, A.; Roche, S. M.; Buchrieser, C.; Cadet-Daniel, V.; Le Monnier, A.; Lecuit, M.; Allerberger, F. (2010). "Listeria rocourtiae sp. nov". International Journal of Systematic and Evolutionary Microbiology. 60 (9): 2210–2214. doi: 10.1099/ijs.0.017376-0 . ISSN 1466-5026. PMID 19915117.
