Yeast communities associated with stingless bees

The yeast communities associated with the stingless bees Tetragonisca angustula, Melipona quadrifasciata and Frieseomelitta varia were studied. The bees T. angustula and F. varia showed a strong association with the yeast Starmerella meliponinorum. M. quadrifasciata more frequently carried a species related to Candida apicola, but also vectored low numbers of S. meliponinorum. Some of the yeasts isolated from adult bees were typical of species known to occur in flowers. Other yeast species found in adult bees were more typical of those found in the phylloplane. S. meliponinorum and the species in the C. apicola complex, also part of the Starmerella clade, may have a mutualistic relationship with the bees studied. Many yeasts in that group are often found in bees or substrates visited by bees, suggesting that a mutually beneficial interaction exists between them.     

Sleep disorders and demand for medical services: evidence from a population-based longitudinal study

Background

The aim of this study was to investigate whether insomnia and obstructive sleep apnea (OSA) were predictors of hospitalizations or emergency department visits during two years following the Sao Paulo Epidemiologic Sleep Study (EPISONO) sample.

Methods and Findings

All participants (n = 1,101) who underwent a baseline evaluation between July and December 2007 were contacted in December 2009 and asked to fill out a questionnaire about body weight changes, number of hospitalizations and visits to the emergency department. Participants lost during the follow-up period represented 3.2% (n = 35) and 7 subjects had died. Hospitalizations were reported by 116 volunteers (10.5%) and emergency department visits were reported by 136 participants (12.4%). The average body mass index (BMI) did not vary significantly between the first and the second assessment [26.7(95%CI:26.3–27.1) vs. 26.9(26.5–27.4) kg/m2]. After adjusting for confounders, a multiple logistic regression model revealed that female gender [1.4(1.0–1.9)], age ≥40 years, insomnia diagnosed according to the DSM-IV criteria [1.6(1.0–2.6)], and apnea-hypopnea index ≥15 [1.5(1.0–2.2)] were predictors of hospitalizations and/or demand for emergency services.

Conclusion

Our study of a probabilistic sample of the Sao Paulo inhabitants shows that over a period of two years, insomnia and OSA were both associated with health impairment. Considering the high prevalence and public health burden of sleep disorders, the consequences of untreated disease for both the individual and society are undeniable and should be addressed.     

Should symptomatic menopausal women be offered hormone therapy?

Many physicians remain uncertain about prescribing hormone therapy for symptomatic women at the onset of menopause. The American Society for Reproductive Medicine (ASRM) convened a multidisciplinary group of healthcare providers to discuss the efficacy and risks of hormone therapy for symptomatic women, and to determine whether it would be appropriate to treat women at the onset of menopause who were complaining of menopausal symptoms. MAJOR FINDINGS: Numerous controlled clinical trials consistently demonstrate that hormone therapy, administered via oral, transdermal, or vaginal routes, is the most effective treatment for vasomotor symptoms. Topical vaginal formulations of hormone therapy should be preferred when prescribing solely for the treatment of symptoms of vulvar and vaginal atrophy. Data from the Women's Health Initiative indicate that the overall attributable risk of invasive breast cancer in women receiving estrogen plus progestin was 8 more cases per 10,000 women-years. No increased risk for invasive breast cancer was detected for women who never used hormone therapy in the past or for those receiving estrogen only. Hormone therapy is not effective for the treatment of cardiovascular disease and that the risk of cardiovascular disease with hormone therapy is principally in older women who are considerably postmenopause. CONCLUSIONS: Healthy symptomatic women should be offered the option of hormone therapy for menopausal symptoms. Symptom relief with hormone therapy for many younger women (at the onset of menopause) with menopausal symptoms outweighs the risks and may provide an overall improvement in quality of life. Hormone therapy should be individualized for symptomatic women. This involves tailoring the regimen and dose to individual needs.     

Dispersal and Burial Behavior in Larvae of <Emphasis Type=Italic>Chrysomya megacephala</Emphasis> and <Emphasis Type=Italic>Chrysomya albiceps</Emphasis> (Diptera,Calliphoridae)

Blowflies use discrete and ephemeral substrates to feed their larva. After they run out of food, the larvae begin to disperse in order to find adequate places for pupation or additional food sources, a process named post-feeding larval dispersal. Briefly state the aspects and why they are important were studied in a circular arena of 25 cm in diameter and covered with wood shavings to a height of 40 cm allowing post-feeding dispersal from the center of the arena. Larvae of both Chrysomya albiceps and C. megacephala were used in five experiments for each species. For each pupa location, determined as distance from the center, depth, and weight were evaluated. Statistical tests were done to verify the relation between weight, depth and distance for pupation and for larvae of two species shows that the media distance is significantly different for two species and for C. megacephala this distance is greater than the distance for C. albiceps. The depth too is different for each species, as the larvae of C. megacephala buries deeper than C. albiceps. With relation of weight, there is no statistic evidence that have any difference between weights for pupation for each species.     

First host record of Epipompilus (Hymenoptera: Pompilidae) from Brazil and discussion of prey carriage mechanism

We register for first time the occurrence of Epipompilus tucumanus Evans, 1967 in Brazil, and record the spider Ariadna boliviana Simon, 1907 as its host. The observations were made in the National Park of Chapada dos Guimarães, Mato Grosso, Brazil. The prey carriage mechanism is described for first time for this genus, and we provide a video showing this behavior.     

Monocyte-Derived Dendritic Cells from Patients with Dermatophytosis Restrict the Growth of Trichophyton rubrum and Induce CD4-T Cell Activation

Dermatophytes are the most common agents of superficial mycoses that are caused by mold fungi. Trichophyton rubrum is the most common pathogen causing dermatophytosis. The immunology of dermatophytosis is currently poorly understood. Recently, our group investigated the interaction of T. rubrum conidia with peritoneal mouse macrophages. We found that macrophages phagocytose T. rubrum conidia resulted in a down-modulation of class II major histocompatibility complex (MHC) antigens and in the expression of co-stimulatory molecules. Furthermore, it induced the production of IL-10, and T. rubrum conidia differentiated into hyphae that grew and killed the macrophages after 8 hrs of culture. This work demonstrated that dendritic cells (DCs) and macrophages, from patients or normal individuals, avidly interact with pathogenic fungus T. rubrum. The dermatophyte has two major receptors on human monocyte-derived DC: DC-SIGN and mannose receptor. In contrast macrophage has only mannose receptor that participates in the phagocytosis or bound process. Another striking aspect of this study is that unlike macrophages that permit rapid growth of T. rubrum, human DC inhibited the growth and induces Th activation. The ability of DC from patients to interact and kill T. rubrum and to present Ags to T cells suggests that DC may play an important role in the host response to T. rubrum infection by coordinating the development of cellular immune response.     

Role of an invariant lysine residue in folate binding on Escherichia coli thymidylate synthase: calorimetric and crystallographic analysis of the K48Q mutant

Thymidylate synthase (TS) catalyzes the reductive methylation of deoxyuridine monophosphate (dUMP) using methylene tetrahydrofolate (CH(2)THF) as cofactor, the glutamate tail of which forms a water-mediated hydrogen bond with an invariant lysine residue of this enzyme. To understand the role of this interaction, we studied the K48Q mutant of Escherichia coli TS using structural and biophysical methods. The k(cat) of the K48Q mutant was 430-fold lower than wild-type TS in activity, while the K(m) for the (R)-stereoisomer of CH(2)THF was 300 microM, about 30-fold larger than K(m) from the wild-type TS. Affinity constants were determined using isothermal titration calorimetry, which showed that binding was reduced by one order of magnitude for folate-like TS inhibitors, such as propargyl-dideazafolate (PDDF) or compounds that distort the TS active site like BW1843U89 (U89). The crystal structure of the K48Q-dUMP complex revealed that dUMP binding is not impaired in the mutant, and that U89 in a ternary complex of K48Q-nucleotide-U89 was bound in the active site with subtle differences relative to comparable wild-type complexes. PDDF failed to form ternary complexes with K48Q and dUMP. Thermodynamic data correlated with the structural determinations, since PDDF binding was dominated by enthalpic effects while U89 had an important entropic component. In conclusion, K48 is critical for catalysis since it leads to a productive CH(2)THF binding, while mutation at this residue does not affect much the binding of inhibitors that do not make contact with this group.     

A short proregion of trialysin, a pore-forming protein of Triatoma infestans salivary glands, controls activity by folding the N-terminal lytic motif

Triatoma infestans (Hemiptera: Reduviidae) is a hematophagous insect that transmits the protozoan parasite Trypanosoma cruzi, the etiological agent of Chagas' disease. Its saliva contains trialysin, a protein that forms pores in membranes. Peptides based on the N-terminus of trialysin lyse cells and fold into alpha-helical amphipathic segments resembling antimicrobial peptides. Using a specific antiserum against trialysin, we show here that trialysin is synthesized as a precursor that is less active than the protein released after saliva secretion. A synthetic peptide flanked by a fluorophore and a quencher including the acidic proregion and the lytic N-terminus of the protein is also less active against cells and liposomes, increasing activity upon proteolysis. Activation changes the peptide conformation as observed by fluorescence increase and CD spectroscopy. This mechanism of activation could provide a way to impair the toxic effects of trialysin inside the salivary glands, thus restricting damaging lytic activity to the bite site.