Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families

In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA.     

Phylogeography of Australian and New Zealand spray zone spiders (Anyphaenidae: Amaurobioides): Moa's Ark loses a few more passengers

Amaurobioides are restricted to the spray zone of southern continents, where they live in small, isolated populations and hunt from silk retreats built in rock crevices. A Star BEAST species tree based on ITS1 nuclear and ND1 mitochondrial genes did not support the hypothesis that this unusual niche linked the evolutionary history of these spiders to geological events reshaping Gondwana into present‐day Australia and New Zealand. Instead, it showed that Amaurobioides reached Australia approximately 4.5 Mya and dispersed twice to New Zealand. Approximately 2.37 Mya, spiders from Tasmania colonized the Deep South of the South Island and, approximately 0.38 Mya, those from South Australia colonized more northern regions. Thus, the present study further limits the scope of the Moa's Ark hypothesis of vicariant New Zealand biogeography.     

The hitchhiker's guide to becoming invasive: exotic mosquitoes spread across a US state by human transport not autonomous flight

Not all exotic species establish and expand aggressively (i.e. become invasive). As potential vectors of disease agents, invasive mosquitoes can have considerable impact on public health, livestock and wildlife; therefore, understanding the species characteristics and ecological circumstances promoting their invasiveness is important. The mosquito Aedes japonicus japonicus, originally from north‐east Asia, was introduced at least two separate times to the north‐eastern USA, as surmised from the initial existence of two populations with distinct nuclear and mitochondrial genetic signatures that later intermixed. Since these original introductions in the late 1990s, Ae. j. japonicus has expanded across 31 US states, two Canadian provinces and five European countries. Although some of the expanded range was due to other independent introductions, to understand what drove the postintroduction expansion of Ae. j. japonicus within the north‐eastern USA, we performed a high‐resolution landscape genetic analysis of 461 specimens collected across Virginia, a state south of the original introductions. All specimens were genotyped at seven pre‐optimized microsatellite loci, and a subsample was sequenced at one mitochondrial locus. We concluded that throughout Virginia this species has primarily expanded in association with humans: genetic distance and distance along roads remained correlated after controlling for geographic distance, and proximity to I‐95, a major interstate highway, strongly predicted nuclear ancestry. In contrast, there was very limited evidence of diffusion even at distances potentially suitable for autonomous mosquito flight. This implies that its association with humans (rather than innate species characteristics) is the single most important determinant of invasiveness in this mosquito.     

Studies of esterase 6 in Drosophila melanogaster. XVIII. Biochemical differences between the slow and fast allozymes

Most natural populations of Drosophila melanogaster are polymorphic for two major electrophoretic variants at the esterase-6 locus. The frequency of the EST 6F allozyme is greatest in populations in warmer latitudes, whereas the EST 6S allozyme is predominant in colder latitudes. Latitudinal clines in electromorph frequencies are found on three continents. Purified preparations of the allozymes have been characterized for their pH optimum, substrate specificity, organophosphate inhibition, alcohol activation, thermal stability, and kinetic parameters. These and previous analyses of the EST 6 allozymes reveal that the two variants have differences in their physical and kinetic properties that may provide a basis for the selective maintenance of the polymorphisms and an explanation of the clinal variation observed in natural populations.      

Sweat gland density and response during high-intensity exercise in athletes with spinal cord injuries

Sweat production is crucial for thermoregulation. However, sweating can be problematic for individuals with spinal cord injuries (SCI), as they display a blunting of sudomotor and vasomotor responses below the level of the injury. Sweat gland density and eccrine gland metabolism in SCI are not well understood. Consequently, this study examined sweat lactate (S-LA) (reflective of sweat gland metabolism), active sweat gland density (SGD), and sweat output per gland (S/G) in 7 SCI athletes and 8 able-bodied (AB) controls matched for arm ergometry VO₂peak. A sweat collection device was positioned on the upper scapular and medial calf of each subject just prior to the beginning of the trial, with iodine sweat gland density patches positioned on the upper scapular and medial calf. Participants were tested on a ramp protocol (7 min per stage, 20 W increase per stage) in a common exercise environment (21±1°C, 45-65% relative humidity). An independent t-test revealed lower (p<0.05) SGD (upper scapular) for SCI (22.3 ±14.8 glands · cm⁻²) vs. AB. (41.0 ± 8.1 glands · cm⁻²). However, there was no significant difference for S/G between groups. S-LA was significantly greater (p<0.05) during the second exercise stage for SCI (11.5±10.9 mmol · l⁻¹) vs. AB (26.8±11.07 mmol · l⁻¹). These findings suggest that SCI athletes had less active sweat glands compared to the AB group, but the sweat response was similar (SLA, S/G) between AB and SCI athletes. The results suggest similar interglandular metabolic activity irrespective of overall sweat rate.     

Rapid purification of native SecA fromEscherichia coli: Development of a new affinity chromatography procedure

The SecA protein occupies a pivotal position in the public protein export pathway inEscherichia coli. The multifunctional SecA protein recognizes cytoplasmic factors associated with export including the presecretory protein and targets the complex to the inner membrane, where it acts in the early stages of protein translocation. The ability of SecA to bind ATP was the basis for the development of a novel, rapid purification scheme involving a single chromatographic step. Affinity chromatography was carried out on Red Sepharose CL-6B. The SecA present in crude extracts ofE. coli binds strongly to this dye-ligand matrix, and active protein was purified to greater than 90% homogeneity. The protein isolated by this procedure retained the previously described ATPase and RNA-binding activities of SecA. This approach should permit the rapid purification of SecA homologs from a variety microorganisms.