RNAi-mediated silencing of vitellogenin gene function turns honeybee (Apis mellifera) workers into extremely precocious foragers

The switch from within-hive activities to foraging behavior is a major transition in the life cycle of a honeybee (Apis mellifera) worker. A prominent regulatory role in this switch has long been attributed to juvenile hormone (JH), but recent evidence also points to the yolk precursor protein vitellogenin as a major player in behavioral development. In the present study, we injected vitellogenin double-stranded RNA (dsVg) into newly emerged worker bees of Africanized genetic origin and introduced them together with controls into observation hives to record flight behavior. RNA interference-mediated silencing of vitellogenin gene function shifted the onset of long-duration flights (> 10 min) to earlier in life (by 3-4 days) when compared with sham and untreated control bees. In fact, dsVg bees were observed conducting such flights extremely precociously, when only 3 days old. Short-duration flights (< 10 min), which bees usually perform for orientation and cleaning, were not affected. Additionally, we found that the JH titer in dsVg bees collected after 7 days was not significantly different from the controls. The finding that depletion of the vitellogenin titer can drive young bees to become extremely precocious foragers could imply that vitellogenin is the primary switch signal. At this young age, downregulation of vitellogenin gene activity apparently had little effect on the JH titer. As this unexpected finding stands in contrast with previous results on the vitellogenin/JH interaction at a later age, when bees normally become foragers, we propose a three-step sequence in the constellation of physiological parameters underlying behavioral development.

Structural shifts of aldehyde dehydrogenase enzymes were instrumental for the early evolution of retinoid-dependent axial patterning in metazoans

Aldehyde dehydrogenases (ALDHs) catabolize toxic aldehydes and process the vitamin A-derived retinaldehyde into retinoic acid (RA), a small diffusible molecule and a pivotal chordate morphogen. In this study, we combine phylogenetic, structural, genomic, and developmental gene expression analyses to examine the evolutionary origins of ALDH substrate preference. Structural modeling reveals that processing of small aldehydes, such as acetaldehyde, by ALDH2, versus large aldehydes, including retinaldehyde, by ALDH1A is associated with small versus large substrate entry channels (SECs), respectively. Moreover, we show that metazoan ALDH1s and ALDH2s are members of a single ALDH1/2 clade and that during evolution, eukaryote ALDH1/2s often switched between large and small SECs after gene duplication, transforming constricted channels into wide opened ones and vice versa. Ancestral sequence reconstructions suggest that during the evolutionary emergence of RA signaling, the ancestral, narrow-channeled metazoan ALDH1/2 gave rise to large ALDH1 channels capable of accommodating bulky aldehydes, such as retinaldehyde, supporting the view that retinoid-dependent signaling arose from ancestral cellular detoxification mechanisms. Our analyses also indicate that, on a more restricted evolutionary scale, ALDH1 duplicates from invertebrate chordates (amphioxus and ascidian tunicates) underwent switches to smaller and narrower SECs. When combined with alterations in gene expression, these switches led to neofunctionalization from ALDH1-like roles in embryonic patterning to systemic, ALDH2-like roles, suggesting functional shifts from signaling to detoxification.

Psychosocial pathways to inconsistent condom use among male sex workers: personality, drug misuse and criminality

Background: This research compared street male sex workers in Santo Andre, Brazil, that reported consistent condom use with those that revealed inconsistent condom use with their clients, concerning personality aspects, impulsiveness, alcohol and drug consumption, depressive symptoms, sociodemographic data and criminal involvement. Methods: Eighty-six male sex workers were evaluated in face-to-face interviews at their place of work. A `snowball` sampling procedure was used to access this hard-to-reach population. Findings: Male sex workers with inconsistent condom use showed greater involvement with criminal activities, higher reward dependence level and more frequent self-report of being HIV-positive. Conclusions: Conceptualisation of male sex workers` psychological characteristics may be required where HIV risk is not only attributed to sex work per se, but to other aspects such as personality-related factors and negative identity.

Rate of occupational leg swelling is greater in the morning than in the afternoon

The aim of this study was to investigate the rate of occupational leg swelling depending on the time period of the working day Volumetric variations of the legs of 70 hospital employees, enrolled in three groups, were evaluated. Group I: 35 morning shift workers; Group II: 35 afternoon shift workers; and Group III: 15 individuals randomly selected from Groups I and II, who were evaluated on the day they worked 12 hours consecutively. Volumetry was performed before and after each shift for both legs of the participants in Groups I and II. For Group III volumetry was performed early in the morning, at noon and in the evening, For statistical analysis, the Student`s t-test and Mann-Whitney test were used with an alpha error of 5%. being considered acceptable (P value < 0.05). Significant increases in volume were recorded for the limbs in all three groups (P value < 0.001). On comparing Groups I and II, the accumulation of fluids was significantly higher in the morning than in the afternoon (P value < 0.003). Asymptomatic workers may present with oedema of the legs during their work with the rate of oedema being different for morning and afternoon shifts. The possibility of wearing compression stockings should be considered for this type of work.

Tuberculosis among health care workers in a Brazilian tertiary hospital emergency unit

The Brazilian emergency system is being reorganized as a hierarchy in the region of Ribeirao Preto, state of Sao Paulo. We found increased occupational risk for tuberculosis in this region tertiary reference center-a nurse technician (Incidence rate [IR] 526.3/100000 inhabitants) had a risk of tuberculosis 12.6 (95% confidence interval [CI], 2.57-37.23) greater than the city population (41.8/100000 inhabitants). The system reorganization will have to make the centers adequate to deal with this problem. (C) 2008 Elsevier Inc. All rights reserved.

Inquiry of antibodies anti-Neospora caninum in dairy cattle, dogs and rural workers of the south-west region of Mato Grosso State

Considering the importance of neosporosis in the animal health and production, the frequency of antibodies to Neospora caninum was evaluated in dairy cattle of the Southwestern region of Mato Grosso State, Brazil, in addition to serum samples obtained from dogs and humans living in the farms. A total of 1036 serum samples were analyzed, from which 932 were from dairy bovine females, 37 from dogs and 67 from humans, from 24 farms and examined by the indirect fluorescent antibody test (IFAT). Reactive human scrum samples were retested by Western-blotting to confirm the results. Antibodies to N. caninum were found in 499 cattle sera (53.5 %), with at least one positive in each farm, 25 dog sera (67.6 %) and seven human sera (10.5 %). There was no significant difference in the number of positive cattle sera according to age group. The results indicate a wide dissemination of N caninum in the studied region.

Seroprevalence of Antibodies to Chlamydophila psittaci in Zoo Workers in Brazil

P>To evaluate the prevalence of antibodies to Chlamydophila psittaci 364 serum samples were collected from veterinarians, biologists, animal scientists, veterinary students, animal keepers and others employees in 20 zoos, and from veterinary practitioners in 10 Brazilian states. Subjects ranged from 15 to 64 years of age, with 268 (74%) males and 96 (26%) females. Chlamydial antibodies were determined by the complement fixation test (CFT) and specific anti-C. psittaci IgG antibodies were determined by the microimmunoflurescence (MIF) test. Complement fixation test showed 23.9% (87/364) and MIF test showed 4.7% (17/364) positive serum samples. Titres ranged from 16 to 256 in both assays, demonstrating evidence of recent or current infection. Although chlamydial antibodies were detected in workers of seventeen zoos, MIF test only detected specific C. psittaci antibodies in seven of them. Previous psittacosis infection was suspected in eight workers of two zoos, five of whom reported having pneumonia, while employed at the zoos. However, diagnosis was not established in any of these cases in the past. Results indicated the occurrence of infection and previous contact of Brazilian zoo workers with C. psittaci, as well as the zoonotic potential of psittacosis in this risk population. Other studies are necessary to evaluate the risk factors of infection in this population. This seroepidemiological survey confirmed the need to adopt preventive measures to control avian chlamydiosis and protect the health of zoo workers in the country.

Factors that prevent or assist the integration of assistive technology into the workplace for people with spinal cord injuries: Perspectives of the users and their employers and co-workers

Examined the barriers faced by people with Spinal Cord Injuries (SCI) when integrating their Assistive Technology (AT) into the workplace, as well as factors that contribute to successful integration. In-depth interviews were taken with 5 men (aged 37-50 yrs) with SCI, 3 of their employers and 2 co-workers. Results indicate that in addition to the barriers previously outlined in the literature related to funding the technology, time delays, information availability, training and maintenance, other issues were highlighted. Implications for service providers are considered in relation to these barriers and the factors that prompted successful integration. The author discusses limitations of the study and makes recommendations for future research. (PsycINFO Database Record (c) 2007 APA, all rights reserved)