Low Temperature Reveals Genetic Variability Against Male-Killing Spiroplasma in Drosophila melanogaster Natural Populations

Spiroplasma endosymbionts are maternally inherited microorganisms which infect many arthropod species. In some Drosophila species, it acts as a reproductive manipulator, spreading in populations by killing the sons of infected mothers. Distinct Drosophila melanogaster populations from Brazil exhibit variable male-killing Spiroplasma prevalences. In this study, we investigated the presence of variability for the male-killing phenotype among Drosophila and/or Spiroplasma strains and verified if it correlates with the endosymbiont prevalence in natural populations. For that, we analyzed the male-killing expression when Spiroplasma strains from different populations were transferred to a standard D. melanogaster line (Canton-S) and when a common Spiroplasma strain was transferred to different wild-caught D. melanogaster lines, both at optimal and challenging temperatures for the bacteria. No variation was observed in the male-killing phenotype induced by different Spiroplasma strains. No phenotypic variability among fly lines was detected at optimal temperature (23 °C), as well. Conversely, significant variation in the male-killing expression was revealed among D. melanogaster lines at 18.5 °C, probably caused by imperfect transmission of the endosymbiont. Distinct lines differed in their average sex ratios as well as in the pattern of male-killing expression as the infected females aged. Greater variation occurred among lines from one locality, although there was no clear correlation between the male-killing intensity and the endosymbiont prevalence in each population. Imperfect transmission or male killing may also occur in the field, thus helping to explain the low or intermediate prevalences reported in nature. We discuss the implications of our results for the dynamics of male-killing Spiroplasma in natural populations.     

Biochemical properties of Candida parapsilosis ecto-5'-nucleotidase and the possible role of adenosine in macrophage interaction

Candida parapsilosis is considered to be an emerging fungal pathogen because it is associated with an increasing range of infections. In this work, we biochemically characterized ecto-5'-nucleotidase activity on the surface of living, intact C. parapsilosis cells. At a pH of 4.5, intact cells were able to hydrolyze 5'-AMP at a rate of 52.44 ± 7.01 nmol Pi h(-1) 10(-7) cells. 5'-AMP, 5'-IMP and 5'-UMP were hydrolyzed at similar rates, whereas 5'-GMP and 5'-CMP hydrolyzed at lower rates. Enzyme activity was increased by about 42% with addition of Mg(2+) or Ca(2+), and the optimum pH was in the acidic range. An inhibitor of phosphatase activities, sodium orthovanadate, showed no effect on AMP hydrolysis; however, as expected, ammonium molybdate, a classical nucleotidase inhibitor, inhibited the activity in a dose-dependent manner. The results indicated that the existence of an ecto-5'-nucleotidase could play a role in the control of extracellular nucleotide concentrations.     

Knockdown of the Rhipicephalus microplus Cytochrome c Oxidase Subunit III Gene Is Associated with a Failure of Anaplasma marginale Transmission

Rhipicephalus microplus is an obligate hematophagous ectoparasite of cattle and an important biological vector of Anaplasma marginale in tropical and subtropical regions. The primary determinants for A. marginale transmission are infection of the tick gut, followed by infection of salivary glands. Transmission of A. marginale to cattle occurs via infected saliva delivered during tick feeding. Interference in colonization of either the tick gut or salivary glands can affect transmission of A. marginale to naïve animals. In this study, we used the tick embryonic cell line BME26 to identify genes that are modulated in response to A. marginale infection. Suppression-subtractive hybridization libraries (SSH) were constructed, and five up-regulated genes {glutathione S-transferase (GST), cytochrome c oxidase sub III (COXIII), dynein (DYN), synaptobrevin (SYN) and phosphatidylinositol-3,4,5-triphosphate 3-phosphatase (PHOS)} were selected as targets for functional in vivo genomic analysis. RNA interference (RNAi) was used to determine the effect of tick gene knockdown on A. marginale acquisition and transmission. Although RNAi consistently knocked down all individually examined tick genes in infected tick guts and salivary glands, only the group of ticks injected with dsCOXIII failed to transmit A. marginale to naïve calves. To our knowledge, this is the first report demonstrating that RNAi of a tick gene is associated with a failure of A. marginale transmission.     

Piperine,a Natural Bioenhancer,Nullifies the Antidiabetic and Antioxidant Activities of Curcumin in Streptozotocin-Diabetic Rats

Knowing that curcumin has low bioavailability when administered orally, and that piperine has bioenhancer activity by inhibition of hepatic and intestinal biotransformation processes, the aim of this study was to investigate the antidiabetic and antioxidant activities of curcumin (90 mg/kg) and piperine (20 or 40 mg/kg), alone or co-administered, incorporated in yoghurt, in streptozotocin (STZ)-diabetic rats. The treatment for 45 days of STZ-diabetic rats with curcumin-enriched yoghurt improved all parameters altered in this experimental model of diabetes: the body weight was increased in association with the weight of skeletal muscles and white adipose tissues; the progressive increase in the glycemia levels was avoided, as well as in the glycosuria, urinary urea, dyslipidemia, and markers of liver (alanine and aspartate aminotransferases and alkaline phosphatase) and kidney (urinary protein) dysfunction; the hepatic oxidative stress was decreased, since the activities of the antioxidant enzymes superoxide dismutase, catalase and gluthatione peroxidase were increased, and the levels of malondialdehyde and protein carbonyl groups were reduced. The dose of 20 mg/kg piperine also showed antidiabetic and antioxidant activities. The treatment of STZ-diabetic rats with both curcumin and 20 mg/kg piperine in yoghurt did not change the antidiabetic and antioxidant activities of curcumin; notably, the treatment with both curcumin and 40 mg/kg piperine abrogated the beneficial effects of curcumin. In addition, the alanine aminotransferase levels were further increased in diabetic rats treated with curcumin and 40 mg/kg piperine in comparison with untreated diabetic rats. These findings support that the co-administration of curcumin with a bioenhancer did not bring any advantage to the curcumin effects, at least about the antidiabetic and antioxidant activities, which could be related to changes on its biotransformation.     

Genomic Characterization of Novel Circular ssDNA Viruses from Insectivorous Bats in Southern Brazil

Circoviruses are highly prevalent porcine and avian pathogens. In recent years, novel circular ssDNA genomes have recently been detected in a variety of fecal and environmental samples using deep sequencing approaches. In this study the identification of genomes of novel circoviruses and cycloviruses in feces of insectivorous bats is reported. Pan-reactive primers were used targeting the conserved rep region of circoviruses and cycloviruses to screen DNA bat fecal samples. Using this approach, partial rep sequences were detected which formed five phylogenetic groups distributed among the Circovirus and the recently proposed Cyclovirus genera of the Circoviridae. Further analysis using inverse PCR and Sanger sequencing led to the characterization of four new putative members of the family Circoviridae with genome size ranging from 1,608 to 1,790 nt, two inversely arranged ORFs, and canonical nonamer sequences atop a stem loop.     

Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons

The herbaceous shrub Tetradenia riparia has been traditionally usedto treat inflammatory and infectious diseases. Recently, a study showed thatT. riparia essential oil (TrEO) obtained in summer hasantileishmanial effects, although these results could be influenced by seasonalvariation. This study evaluated the activity of the TrEO obtained in differentseasons against Leishmania (Leishmania) amazonensis, in vitro and invivo. The compounds in the TrEO were analysed by gas chromatography-massspectrometry; terpenoids were present and oxygenated sesquiterpenes were the majoritycompounds (55.28%). The cytotoxicity and nitric oxide (NO) production were alsotested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitoryconcentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEOreduced intracellular amastigote infection, independently of season. The TrEO fromplants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mLfor J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NOproduction did not change in samples of the TrEO from different seasons. Theantileishmanial effect in vivo consisted of a reduction of the parasite load in thespleen. These results suggest that the TrEO has potential effects on L. (L.)amazonensis, consonant with its traditional use to treat parasiticdiseases.     

Sleep quality in chronic kidney patients: a systematic review

The maintenance of sleep quality improves an individual’s quality of life and reduces the risk of death associated with disease, such as chronic kidney disease (CKD) (progressive and irreversible loss of kidney function). Poor sleep quality can negatively affect immunity, cognitive functions, and emotional manifestations. CKD patients have poor sleep quality in approximately 80% of cases. A systematic literature review was undertaken using online data bases. 73,734 studies were found, 21 of which met our inclusion criteria and were subject to detailed analysis. Although renal transplantation appears to be promising with regard to improving the quality of sleep of kidney patients, there is still a high prevalence of poor sleep even after the operation. Longitudinal studies are needed to understand better the risk factors that are involved and to indicate possible treatments that may improve the overall quality of life in this section of the population.     

Better to Be in Bad Company than to Be Alone? Aedes Vectors Respond Differently to Breeding Site Quality in the Presence of Others

This study focuses on two competing species, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), both invasive mosquitoes of the New World. Context-specific competition between immature forms inside containers seems to be an important determinant of the coexistence or displacement of each species in different regions of the world. Here, competition experiments developed at low density (one, two or three larvae) and receiving four different resource food concentration, were designed to test whether Ae. albopictus and Ae. aegypti respond differently to competition, and whether competition can be attributed to a simple division of resources. Three phenotypic traits - larval development, adult survival under starvation and wing length - were used as indicators of performance. Larvae of neither species were limited by resource concentration when they were alone, unlike when they developed with competitors. The presence of conspecifics affected Ae. aegypti and Ae. albopictus, inducing slower development, reduced survival and wing length. The response to resource limitation was different when developing with heterospecifics: Ae. aegypti developing with one heterospecific showed faster development, producing smaller adults with shorter lives, while in the presence of two competitors, development increased and adults lived longer. Aedes albopictus demonstrated a better performance when developing with heterospecifics, with no loss in their development period and improved adult survival. Overall, our results suggest that response to competition can not simply be attributed to the division of resources, and that larvae of both species presented large phenotypic plasticity in their response to the presence or absence of heterospecifics and conspecifics.