Spatiotemporal Distribution and Environmental Drivers of Barley yellow dwarf virus and Vector Abundance in Kansas.

Several aphid species transmit barley yellow dwarf, a globally destructive disease caused by viruses that infect cereal grain crops. Data from >400 samples collected across Kansas wheat fields in 2014 and 2015 were used to develop spatiotemporal models predicting the extent to which landcover, temperature and precipitation affect spring aphid vector abundance and presence of individuals carrying Barley yellow dwarf virus (BYDV). The distribution of Rhopalosiphum padi abundance was not correlated with climate or landcover, but Sitobion avenae abundance was positively correlated with fall temperature and negatively correlated to spring temperature and precipitation. The abundance of Schizaphis graminum was negatively correlated with fall precipitation and winter temperature. The incidence of viruliferous (+BYDV) R. padi was positively correlated with fall precipitation but negatively correlated with winter precipitation. In contrast, the probability of +BYDV S. avenae was unaffected by precipitation but was positively correlated with fall temperatures and distance to forest or shrubland. R. padi and S. avenae were more prevalent at eastern sample sites where ground cover is more grassland than cropland, suggesting that grassland may provide over-summering sites for vectors and pose a risk as potential BYDV reservoirs. Nevertheless, land cover patterns were not strongly associated with differences in abundance or the probability that viruliferous aphids were present.

Reduction in the cumulative effect of stress-induced inbreeding depression due to intragenerational purging in Drosophila melanogaster.

Environmental stress generally exacerbates the harmful effects of inbreeding and it has been proposed that this could be exploited in purging deleterious alleles from threatened inbred populations. However, understanding what factors contribute to variability in the strength of inbreeding depression (ID) observed across adverse environmental conditions remains a challenge. Here, we examined how the nature and timing of stress affects ID and the potential for purging using inbred and outbred Drosophila melanogaster larvae exposed to biotic (larval competition, bacteria infection) and abiotic (ethanol, heat) stressors compared with unstressed controls. ID was measured during (larval survival) and after (male mating success) stress exposure. The level of stress imposed by each stressor was approximately equal, averaging a 42% reduction in outbred larval survival relative to controls. All stressors induced on average the same ID, causing a threefold increase in lethal equivalents for larval survival relative to controls. However, stress-induced ID in larval success was followed by a 30% reduction in ID in mating success of surviving males. We propose that this fitness recovery is due to 'intragenerational purging' whereby fitness correlations facilitate stress-induced purging that increases the average fitness of survivors in later life history stages. For biotic stressors, post-stress reductions in ID are consistent with intragenerational purging, whereas for abiotic stressors, there appeared to be an interaction between purging and stress-induced physiological damage. For all stressors, there was no net effect of stress on lifetime ID compared with unstressed controls, undermining the prediction that stress enhances the effectiveness of population-level purging across generations.

Sex-specific effects of inbreeding in wild-caught Drosophila melanogaster under benign and stressful conditions.

In animal populations, sib mating is often the primary source of inbreeding depression (ID). We used recently wild-caught Drosophila melanogaster to test whether such ID is amplified by environmental stress and, in males, by sexual selection. We also investigated whether increased ID because of stress (increased larval competition) persisted beyond the stressed stage and whether the effects of stress and sexual selection interacted. Sib mating resulted in substantial cumulative fitness losses (egg to adult reproduction) of 50% (benign) and 73% (stressed). Stress increased ID during the larval period (23% vs. 63%), but not during post-stress reproductive stages (36% vs. 31%), indicating larval stress may have purged some adult genetic load (although ID was uncorrelated across stages). Sexual selection exacerbated inbreeding depression, with inbred male offspring suffering a higher reproductive cost than females, independent of stress (57% vs. 14% benign, 49% vs. 11% stress).

Evolution of sex-specific wing shape at the widerwing locus in four species of Nasonia.

How do morphological differences between species evolve at the genetic level? This study investigates the genetic basis of recent divergence in male wing size between species of the model parasitoid wasp Nasonia. The forewings of flightless Nasonia vitripennis males are 2.3 times smaller than males of their flighted sister species N. giraulti. We describe a major genetic contributor to this difference: the sex-specific widerwing (wdw) locus, which we have backcrossed from N. giraulti into N. vitripennis and mapped to an 0.9 megabase region of chromosome 1. This introgression of wdw from large-winged N. giraulti into small-winged N. vitripennis increases male but not female forewing width by 30% through wing region-specific size changes. Indirect evidence suggests that cell number changes across the wing explain the majority of the wdw wing-size difference, whereas changes in cell size are important in the center of the wing. Introgressing the same locus from the other species in the genus, N. longicornis and N. oneida, into N. vitripennis produces intermediate and large male wing sizes. To our knowledge, this is the first study to introgress a morphological quantitative trait locus (QTL) from multiple species into a common genetic background. Epistatic interactions between wdw and other QTL are also identified by introgressing wdw from N. vitripennis into N. giraulti. The main findings are (1) the changes at wdw have sex- and region-specific effects and could, therefore, be regulatory, (2) the wdw locus seems to be a co-regulator of cell size and cell number, and (3) the wdw locus has evolved different wing width effects in three species.

The genetic basis of interspecies host preference differences in the model parasitoid Nasonia.

The genetic basis of host preference has been investigated in only a few species. It is relevant to important questions in evolutionary biology, including sympatric speciation, generalist versus specialist adaptation, and parasite-host co-evolution. Here we show that a major locus strongly influences host preference in Nasonia. Nasonia are parasitic wasps that utilize fly pupae; Nasonia vitripennis is a generalist that parasitizes a diverse set of hosts, whereas Nasonia giraulti specializes in Protocalliphora (bird blowflies). In laboratory choice experiments using Protocalliphora and Sarcophaga (flesh flies), N. vitripennis shows a preference for Sarcophaga, whereas N. giraulti shows a preference for Protocalliphora. Through a series of interspecies crosses, we have introgressed a major locus affecting host preference from N. giraulti into N. vitripennis. The N. giraulti allele is dominant and greatly increases preference for Protocalliphora pupae in the introgression line relative to the recessive N. vitripennis allele. Through the utilization of a Nasonia genotyping microarray, we have identified the introgressed region as 16 Mb of chromosome 4, although a more complete analysis is necessary to determine the exact genetic architecture of host preference in the genus. To our knowledge, this is the first introgression of the host preference of one parasitoid species into another, as well as one of the few cases of introgression of a behavioral gene between species.

Etiology of musician's dystonia: familial or environmental?

OBJECTIVE: To test the hypothesis that there is familial aggregation of dystonia and other movement disorders in relatives of patients with musician's dystonia (MD) and to identify possible environmental triggers. METHODS: The families of 28 index patients with MD (14 with a reported positive family history of focal task-specific dystonia [FTSD] and 14 with no known family history [FH-]) underwent a standardized telephone screening interview using a modified version of the Beth Israel Dystonia Screen. Videotaped neurologic examinations were performed on all participants who screened positive and consensus diagnoses established. All patients were investigated for DYT1 dystonia and suitable families were tested for linkage to DYT7. All family members were administered questionnaires covering potential triggers of FTSD. RESULTS: A diagnosis of dystonia was established in all 28 index patients and in 19/97 examined relatives (MD: n = 8, other FTSD: n = 9, other dystonias: n = 2), 5 of whom were members of FH- families. In 27 of the 47 affected individuals, additional forms of dystonia were seen; other movement disorders were observed in 23 patients. In total, 18 families were multiplex families with two to four affected members. Autosomal dominant inheritance was compatible in at least 12 families. The GAG deletion in DYT1 was absent in all patients. Linkage to DYT7 could be excluded in 1 of the 11 informative families. With respect to potential environmental triggers, there was no significant difference between patients with MD/FTSD compared to unaffected family members. CONCLUSION: Our results suggest a genetic contribution to musician's dystonia with phenotypic variability including focal task-specific dystonia.

Factors associated with balance deficits on admission to rehabilitation after traumatic brain injury: a multicenter analysis.

OBJECTIVE: To evaluate how demographics, measures of injury severity, and acute care complications relate to sitting and standing balance in patients with traumatic brain injury (TBI). DESIGN: Multicenter analysis of consecutive admissions to designated TBI Model Systems of Care (TBIMS). SETTING: Ten National Institute for Disability and Rehabilitation Research TBI Model System centers for coordinated acute and rehabilitation care. PARTICIPANTS: 908 adults with TBI were included in the study. MAIN OUTCOME MEASURES: Sitting and standing balance were assessed within 72 hours of admission to inpatient rehabilitation. RESULTS: Age less than 50 years had a significant association with normal sitting and standing balance (P =.001 and.05, respectively). Measures of severity of traumatic brain injury, including admission Glasgow Coma Score, length of posttraumatic amnesia (PTA), length of coma, and acute care length of stay were each significantly related to impaired sitting and standing balance ratings (P <.01). Initial abnormalities in pupillary response had a significant relationship with impairment of sitting (P =.009) but not standing balance. Incidence of respiratory failure, pneumonia, soft tissue infections, and urinary tract infections were all related to impaired sitting balance (P <.01). Presence of intracranial hemorrhages did not have a significant relationship with either sitting or standing balance. Intracranial compression had a significant relationship with standing (P =.05) but not sitting balance. A discriminant function analysis, which included neuroradiological findings, injury severity, and medical complications, could not accurately predict impaired balance ratings. CONCLUSIONS: This study demonstrated that rehabilitation admission balance ratings have a significant relationship with age, multiple measures of severity, and acute care medical complications after TBI. Prospective studies are indicated to evaluate the role balance at rehabilitation admission plays in the functional prognosis of patients with TBI.

Treating chemical dependency: the need for including the family.

Regression analysis was used to test Family Systems Therapy as a fruitful approach in chemical dependency treatment. Results indicate that the concerned person's perceptions of family life are critical in determining whether a family completes therapy or terminates early. Using both family and individual level variables, the significance and direction of the coefficients are consistent with the Family Systems Therapy model. Results support the importance of including the family in chemical dependency treatment.

Tetraethylene glycol diacrylate. A cause of delayed cutaneous irritant reaction and allergic contact dermatitis.

A woman who worked as a materials handler in a plant manufacturing acrylated chemicals developed allergic contact allergy to tetraethylene glycol diacrylate (TTEGDA). Four co-workers experienced skin irritation 12 to 36 hours after skin contact with TTEGDA but had no immediate reaction at the time of exposure. The chemical sensitized the albino guinea pig in the guinea pig maximization test. By varying parameters such as the administration of Freund's complete adjuvent, the intradermal concentration injected for induction, and the diluent used for the injections, it was possible to alter the apparent sensitization potential of TTEGDA.

Kinetics of viral replication and local and systemic immune responses in experimental rotavirus infection.

Rotavirus-seronegative mice were orally inoculated with murine rotavirus in order to study the kinetics of rotavirus replication and the relationship of viral replication to immunity and disease and to assess the effects of local and systemic antibodies on viral clearance and disease resolution.