Genetic studies on hexokinase in the mosquitoAedes togoi

Hexokinases (EC 2.7.1.1) were genetically analyzed in the mosquitoAedes togoi by agar gel electrophoresis. Enzyme activity was observed anodally in one major banding region (HK-1) on the gel and in another faintly stained region (HK-2). A total of six bands was detected in the HK-1 region. All six bands could be detected in three body parts, head, thorax, and abdomen, of adults with different banding intensities. The third and fourth bands, numbered from the more anodal side, showed the broadest substrate specificity and the greatest enzyme activity throughout development. Genetic analysis of the six HK-1 bands was undertaken on the hypothesis of a single gene locus (or three extremely tightly linked loci). The analysis gave the following gene order:HK-1—4.2±1.8 (recombination units±SE)—To-2—Odh-2—29.5±2.5—sex (M/m)—s. A comparison is made of gene loci for hexokinases among the mosquito speciesCulex pipiens, Aedes aegypti, and this species, along with a comment on linkage relationships betweenHk andOdh (octanol dehydrogenase) loci in threeAedes species.This research was supported by National Institutes of Health Grant AI 16983 and a Grant-in-Aid for Co-operative Research (57340033) from the Ministry of Education, Science and Culture, Japan.     

Influence of a long-term powdered diet on the social interaction test and dopaminergic systems in mice

It is well known that the characteristics of mastication are important for the maintenance of our physical well-being. In this study, to assess the importance of the effects of food hardness during mastication, we investigated whether a long-term powdered diet might cause changes in emotional behavior tests, including spontaneous locomotor activity and social interaction (SI) tests, and the dopaminergic system of the frontal cortex and hippocampus in mice. Mice fed a powdered diet for 17 weeks from weaning were compared with mice fed a standard diet (control). The dopamine turnover and expression of dopamine receptors mRNA in the frontal cortex were also evaluated. Spontaneous locomotor activity, SI time and dopamine turnover of the frontal cortex were increased in powdered diet-fed mice. On the other hand, the expression of dopamine-4 (D4) receptors mRNA in the frontal cortex was decreased in powdered diet-fed mice. Moreover, we examined the effect of PD168077, a selective D4 agonist, on the increased SI time in powdered diet-fed mice. Treatment with PD168077 decreased the SI time. These results suggest that the masticatory dysfunction induced by long-term powdered diet feeding may cause the increased SI time and the changes in the dopaminergic system, especially dopamine D4 receptor subtype in the frontal cortex.     

Development of a micro-neutralization test for chikungunya virus

A rapid, micro-scale focus reduction neutralization test for chikungunya virus was developed. In the test, cell monolayers are prepared in a 96-well tissue culture plate and the PAP (peroxidase-antiperoxidase) staining technique is used for detection of foci of chikungunya virus infected cells. This test is suitable for rapid diagnosis and epidemiological studies of the virus.     

An improved micromethod for infectivity assays and neutralization tests of dengue viruses

An improved micromethod for infectivity assays and neutralization (N) tests of dengue (DEN) type 1-4 viruses was developed, using 96-well plates and the PAP (peroxidase-antiperoxidase) staining technique. The foci formed on BHK-21 cell monolayers in wells of the plate were readily countable under an ordinary stereomicroscope. This micromethod has the advantages over the micromethod of the Lab-Tek 8 chamber slide system of lower cost, requirement for smaller volumes of test sera and applicability to larger number of serum specimens for N tests of DEN viruses.     

Six-Year Trend Analysis of Nosocomial Candidemia and Risk factors in Two Intensive Care Hospitals in Mato Grosso, Midwest Region of Brazil

We conducted this cross-sectional retrospective study using clinical and laboratory data from two tertiary hospitals in Cuiabá, Mato Grosso, Brazil, in order to explore the risk factors and estimate mortality, prevalence and lethality of candidemia between 2006 and 2011. A total of 130 episodes of candidemia were identified. The prevalence of candidemia was 1.8 per 1,000 admissions, the mortality rate was 0.9 per 1,000 admissions, and the lethality was 49.2 %. The main agent in this population was Candida parapsilosis (n = 50), followed by C. albicans (n = 45). Comparison between the numbers of episodes in the two triennia revealed that the non-albicans group grew by 48.2 %. The distribution of yeast species of Candida per hospital unit revealed that C. albicans was more prevalent than C. parapsilosis in the adult ICU and C. parapsilosis was more prevalent than C. albicans in the neonatal ICU. Patients remained hospitalized for an average of 53.5 days. Central venous catheters, parenteral nutrition and age were the variables that proved to be independent in the multivariate analysis and that maintained a statistically significant association with the incidence of death in patients with candidemia. The annual prevalence of candidemia showed a significant increase in the second triennium (2009–2011) compared with the first (2006–2008) probably due to increased exposure to risk factors: central venous catheter, H2 blockers, nutrition parenteral corticosteroids and mean hospital duration.     

Genetics of octanol and α-glycerophosphate dehydrogenases in the mosquito Aedes (Finlaya) togoi

Genetic studies were performed on octanol dehydrogenase (EC 1.1.1.73) and alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) in the mosquito Aedes (Finlaya) togoi by agar gel electrophoresis. The electrophoretic survey revealed two octanol dehydrogenase loci (Odh-1, Odh-2) and one alpha-glycerophosphate dehydrogenase locus (alpha-Gpdh) in this species. Five alleles were observed at the Odh-2 locus in seven laboratory strains, whereas the alpha-Gpdh locus was completely monomorphic in six of seven strains examined and the second allele at this locus was detected in only one strain at a frequency of 0.14. Both loci code for dimeric enzymes. Linkage studies on Odh-2 and alpha-Gpdh suggested that the gene arrangement and recombination units were Odh-2--(25.8)--M (sex locus)--(30.5)--s (strawcolored larva) and M--(25.6)--alpha-Gpdh--(15.4)--s. These results, together with linkage data previously reported, give the following gene linkage on the sex chromosome: Odh-2--Est-3 (carboxylesterase)--Acph (acid phosphatase)--M--alpha-Gpdh--s--Est-2 (carboxylesterase). The total map length of this arrangement is approximately 75 map units.