scholarly journals Characterization of the β-Ketoadipate Pathway in Sinorhizobium meliloti

2006 ◽  
Vol 72 (8) ◽  
pp. 5403-5413 ◽  
Author(s):  
Allyson M. MacLean ◽  
Gordon MacPherson ◽  
Punita Aneja ◽  
Turlough M. Finan
Keyword(s):  
Aromatic Compounds ◽  
Related Species ◽  
Sinorhizobium Meliloti ◽  
Transcriptional Regulator ◽  
Transferase Activity ◽  
Catabolic Pathway ◽  
Closely Related Species ◽  
Coa Transferase ◽  
Transcriptional Units

ABSTRACT Aromatic compounds represent an important source of energy for soil-dwelling organisms. The β-ketoadipate pathway is a key metabolic pathway involved in the catabolism of the aromatic compounds protocatechuate and catechol, and here we show through enzymatic analysis and mutant analysis that genes required for growth and catabolism of protocatechuate in the soil-dwelling bacterium Sinorhizobium meliloti are organized on the pSymB megaplasmid in two transcriptional units designated pcaDCHGB and pcaIJF. The pcaD promoter was mapped by primer extension, and expression from this promoter is demonstrated to be regulated by the LysR-type protein PcaQ. β-Ketoadipate succinyl-coenzyme A (CoA) transferase activity in S. meliloti was shown to be encoded by SMb20587 and SMb20588, and these genes have been renamed pcaI and pcaJ, respectively. These genes are organized in an operon with a putative β-ketoadipyl-CoA thiolase gene (pcaF), and expression of the pcaIJF operon is shown to be regulated by an IclR-type transcriptional regulator, SMb20586, which we have named pcaR. We show that pcaR transcription is negatively autoregulated and that PcaR is a positive regulator of pcaIJF expression and is required for growth of S. meliloti on protocatechuate as the carbon source. The characterization of the protocatechuate catabolic pathway in S. meliloti offers an opportunity for comparison with related species, including Agrobacterium tumefaciens. Differences observed between S. meliloti and A. tumefaciens pcaIJ offer the first evidence of pca genes that may have been acquired after speciation in these closely related species.

The Ornithodoros capensis group (Acari: Argasidae): a morphological diagnosis and molecular characterization of O. capensis sensu stricto from Queimada Grande Island, Brazil 

2017 ◽  
Vol 22 (1) ◽  
pp. 28 ◽  
Author(s):  
Sebastián Muñoz-Leal ◽  
Ricardo A. Dias ◽  
Carlos R. Abrahão ◽  
Marcelo B. Labruna
Keyword(s):  
Molecular Characterization ◽  
Related Species ◽  
Morphological Analysis ◽  
Bacterial Pathogens ◽  
Sensu Stricto ◽  
Closely Related Species ◽  
Paulo State ◽  
Morphological Diagnosis ◽  
First Time

Ornithodoros capensis sensu lato (s. l.) is a worldwide-distributed group of soft ticks that parasitize birds in insular and continental lands. It is currently composed of 11 morphologically closely related species. Several viral and bacterial pathogens, and particularly Coxiella-like endosymbiont organisms have been described coexisting with ticks of this group. Since it last report in 1983, the presence of O. capensis s. l. in Brazil has remained undocumented. By a morphological analysis of larvae and a molecular characterization of ticks and Coxiella genes we describe for the first time O. capensis sensu stricto in Brazil from specimens collected on Queimada Grande Island, in São Paulo state.

scholarly journals Evolutionary characterization of a Y chromosomal sequence conserved in the genus Mus

1988 ◽  
Vol 52 (2) ◽  
pp. 145-150 ◽  
Author(s):  
Yutaka Nishioka
Keyword(s):  
Related Species ◽  
Rattus Norvegicus ◽  
Phylogenetic Relationships ◽  
Repetitive Sequence ◽  
Repetitive Sequences ◽  
Closely Related Species ◽  
Specific Hybridization ◽  
Male Specific ◽  
Chromosomal Sequence

SummaryThe extent of accumulation of mouse Y chromosomal repetitive sequences generally correlates with the known phylogenetic relationships in the genus Mus. However, we describe here a M. musculus Y chromosomal repetitive sequence, designated as ACClfl, whose accumulation patterns among eight Mus species do not correspond to their phylogenetic relationships. Although male-specific hybridization bands were present in all the species examined, significant accumulation (> 200 copies) in the Y chromosomes was found in M. minutoides (subgenus Nannomys), M. pahari (subgenus Coelomys) and M. saxicola (subgenus Pyromys) as well as in the three closely related species M. hortulanus, M. musculus and M. spretus that belong to the subgenus Mus. Unexpectedly, the Y chromosomes of M. caroli and M. cookii (both subgenus Mus) had considerably reduced amounts of ACClfl-related sequences. Furthermore, in rats (Rattus norvegicus) the major accumulation sites appear to be autosomal. These observations suggest that caution must be taken in the interpretation of data obtained with repetitive sequences that have evolved quickly.

scholarly journals An antimicrobial Staphylococcus sciuri with broad temperature and salt spectrum isolated from the surface of the African social spider, Stegodyphus dumicola

2021 ◽  
Author(s):  
Seven Nazipi ◽  
Sofie Gerdes Vangkilde-Pedersen ◽  
Mette Marie Busck ◽  
Dorthe Kirstine Lund ◽  
Ian P.G. Marshall ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Related Species ◽  
Phenotypic Characterization ◽  
Phylogenomic Analysis ◽  
Closely Related Species ◽  
Social Spider ◽  
Social Spiders ◽  
Mutualistic Symbiosis ◽  
The Social

Abstract Some social arthropods engage in mutualistic symbiosis with antimicrobial compound-producing microorganisms that provide protection against pathogens. Social spiders live in communal nests and contain specific endosymbionts with unknown function. Bacteria are also found on the spiders' surface, including prevalent staphylococci, which may have protective potential. Here we present the genomic and phenotypic characterization of strain i1, isolated from the surface of the social spider Stegodyphus dumicola. Phylogenomic analysis identified i1 as novel strain of Staphylococcus sciuri within subgroup 2 of three newly defined genomic subgroups. Further phenotypic investigations showed that S. sciuri i1 is an extremophile that can grow at a broad range of temperatures (4°C-45°C), high salt concentrations (up to 27%), and has antimicrobial activity against closely related species. We identified a lactococcin 972-like bacteriocin gene cluster, likely responsible for the antimicrobial activity, and found it conserved in two of the three subgroups of S. sciuri. These features indicate that S. sciuri i1, though not a specific symbiont, is well-adapted to survive on the surface of social spiders and may gain a competitive advantage by inhibiting closely related species.

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