The Specificity of ParR Binding Determines the Incompatibility of Conjugative Plasmids in Clostridium perfringens.

Plasmids that encode the same replication machinery are generally unable to coexist in the same bacterial cell. However, Clostridium perfringens strains often carry multiple conjugative toxin or antibiotic resistance plasmids that are closely related and encode similar Rep proteins. In many bacteria, plasmid partitioning upon cell division involves a ParMRC system; in C.

An Early Pandemic Analysis of SARS-CoV-2 Population Structure and Dynamics in Arizona.

In December of 2019, a novel coronavirus, SARS-CoV-2, emerged in the city of Wuhan, China, causing severe morbidity and mortality. Since then, the virus has swept across the globe, causing millions of confirmed infections and hundreds of thousands of deaths. To better understand the nature of the pandemic and the introduction and spread of the virus in Arizona, we sequenced viral genomes from clinical samples tested at the TGen North Clinical Laboratory, the Arizona Department of Health Services, and those collected as part of community surveillance projects at Arizona State University and the University of Arizona.

The ever-expanding tcp conjugation locus of pCW3 from Clostridium perfringens.

The spore-forming, anaerobic Gram positive pathogen Clostridium perfringens encodes many of its disease-causing toxins on closely related conjugative plasmids. Studies of the tetracycline resistance plasmid pCW3 have identified many of the genes involved in conjugative transfer, which are located in the tcp conjugation locus. Upstream of this locus is an uncharacterised region (the cnaC region) that is highly conserved.

A near full-length HIV-1 genome from 1966 recovered from formalin-fixed paraffin-embedded tissue.

With very little direct biological data of HIV-1 from before the 1980s, far-reaching evolutionary and epidemiological inferences regarding the long prediscovery phase of this pandemic are based on extrapolations by phylodynamic models of HIV-1 genomic sequences gathered mostly over recent decades. Here, using a very sensitive multiplex RT-PCR assay, we screened 1,645 formalin-fixed paraffin-embedded tissue specimens collected for pathology diagnostics in Central Africa between 1958 and 1966. We report the near-complete viral genome in one HIV-1 positive specimen from Kinshasa, Democratic Republic of Congo (DRC), from 1966 ("DRC66")-a nonrecombinant sister lineage to subtype C that constitutes the oldest HIV-1 near full-length genome recovered to date.

Virulence Plasmids of the Pathogenic Clostridia.

The clostridia cause a spectrum of diseases in humans and animals ranging from life-threatening tetanus and botulism, uterine infections, histotoxic infections and enteric diseases, including antibiotic-associated diarrhea, and food poisoning. The symptoms of all these diseases are the result of potent protein toxins produced by these organisms. These toxins are diverse, ranging from a multitude of pore-forming toxins to phospholipases, metalloproteases, ADP-ribosyltransferases and large glycosyltransferases.

pCP13, a representative of a new family of conjugative toxin plasmids in Clostridium perfringens.

Conjugative transfer is a major contributor to the dissemination of antibiotic resistance and virulence genes in the human and animal pathogen, Clostridium perfringens. The C. perfringens plasmid pCW3 is the archetype of an extensive family of highly related conjugative toxin and antibiotic resistance plasmids found in this bacterium.

Pathogenicity Locus Plasmid pCS1-1 Encodes a Novel Clostridial Conjugation Locus.

A major virulence factor in -mediated infection is the toxin TcsL, which is encoded within a region of the genome called the pathogenicity locus (PaLoc). isolates carry the PaLoc on the pCS1 family of plasmids, of which there are four characterized members. Here, we determined the potential mobility of pCS1 plasmids and characterized a fifth unique pCS1 member.

Evidence that compatibility of closely related replicons in Clostridium perfringens depends on linkage to parMRC-like partitioning systems of different subfamilies.

Clostridium perfringens produces an extensive repertoire of toxins and extracellular enzymes, many of which are intimately involved in the progression of disease and are encoded by genes on conjugative plasmids. In addition, many C. perfringens strains can carry up to five of these conjugative toxin or antimicrobial resistance plasmids, each of which has a similar 35kb backbone.

1970s and 'Patient 0' HIV-1 genomes illuminate early HIV/AIDS history in North America.

The emergence of HIV-1 group M subtype B in North American men who have sex with men was a key turning point in the HIV/AIDS pandemic. Phylogenetic studies have suggested cryptic subtype B circulation in the United States (US) throughout the 1970s and an even older presence in the Caribbean. However, these temporal and geographical inferences, based upon partial HIV-1 genomes that postdate the recognition of AIDS in 1981, remain contentious and the earliest movements of the virus within the US are unknown.

Plasmid partitioning systems of conjugative plasmids from Clostridium perfringens.

Many pathogenic strains of Clostridium perfringens carry several highly similar toxin or antibiotic resistance plasmids that have 35 to 40 kb of very closely related syntenous sequences, including regions that carry the genes encoding conjugative transfer, plasmid replication and plasmid maintenance functions. Key questions are how are these closely related plasmids stably maintained in the same cell and what is the basis for plasmid incompatibility in C. perfringens.

Density dynamics of diverse Spiroplasma strains naturally infecting different species of Drosophila.

Facultative heritable bacterial endosymbionts can have dramatic effects on their hosts, ranging from mutualistic to parasitic. Within-host bacterial endosymbiont density plays a critical role in maintenance of a symbiotic relationship, as it can affect levels of vertical transmission and expression of phenotypic effects, both of which influence the infection prevalence in host populations. Species of genus Drosophila are infected with Spiroplasma, whose characterized phenotypic effects range from that of a male-killing reproductive parasite to beneficial defensive endosymbiont.

Proteomic analysis of Drosophila mojavensis male accessory glands suggests novel classes of seminal fluid proteins.

Fruit-flies of the genus Drosophila are characterized by overwhelming variation in fertilization traits such as copulatory plug formation, sperm storage organ use, and nutritional ejaculatory donation. Despite extensive research on the genetic model Drosophila melanogaster, little is known about the molecular underpinnings of these interspecific differences. This study employs a proteomic approach to pin-point candidate seminal fluid proteins in Drosophila mojavensis, a cactophilic fruit-fly that exhibits divergent reproductive biology when compared to D.

Desiccation resistance in four Drosophila species: sex and population effects.

Desiccation resistance and body mass were measured in multiple populations of each of four species of Drosophila: two desert endemic species (D. nigrospiracula and D. mojavensis), and two with more widespread distributions (D.

Functional genomics of cactus host shifts in Drosophila mojavensis.

Understanding the genetic basis of adaptation to novel environments remains one of the major challenges confronting evolutionary biologists. While newly developed genomic approaches hold considerable promise for addressing this overall question, the relevant tools have not often been available in the most ecologically interesting organisms. Our study organism, Drosophila mojavensis, is a cactophilic Sonoran Desert endemic utilizing four different cactus hosts across its geographical range.