Dengue and Zika virus infection patterns vary among Aedes aegypti field populations from Belo Horizonte,a Brazilian endemic city

Dengue virus (DENV) and Zika virus (ZIKV) belong to the same viral family, the Flaviviridae. They cause recurring threats to the public health systems of tropical countries such as Brazil. The primary Brazilian vector of both viruses is the mosquito Aedes aegypti. After the mosquito ingests a blood meal from an infected person, the viruses infect and replicate in the midgut, disseminate to secondary tissues and reach the salivary gland (SG), where they are ready to be transmitted to a vertebrate host. It is thought that the intrinsic discrepancies among mosquitoes could affect their ability to deal with viral infections. This study confirms that the DENV and ZIKV infection patterns of nine Ae. aegypti field populations found in geographically separate health districts of an endemic Brazilian city vary. We analyzed the infection rate, disseminated infection, vector competence, and viral load through quantitative PCR. Mosquitoes were challenged using the membrane-feeding assay technique and were tested seven and fourteen days post-infection (early and late infection phases, respectively). The infection responses varied among the Ae. aegypti populations for both flaviviruses in the two infection phases. There was no similarity between DENV and ZIKV vector competencies or viral loads. According to the results of our study, the risk of viral transmission overtime after infection either increases or remains unaltered in ZIKV infected vectors. However, the risk may increase, decrease, or remain unaltered in DENV-infected vectors depending on the mosquito population. For both flaviviruses, the viral load persisted in the body even until the late infection phase. In contrast to DENV, the ZIKV accumulated in the SG over time in all the mosquito populations. These findings are novel and may help direct the development of control strategies to fight dengue and Zika outbreaks in endemic regions, and provide a warning about the importance of understanding mosquito responses to arboviral infections.     

Photoinhibition and recovery in a herbicide-resistant mutant from<Emphasis Type="Italic"> Glycine max</Emphasis> (L.) Merr. cell cultures deficient in fatty acid unsaturation

Photoinhibition and recovery were studied in two photosynthetic cell suspensions from soybean (Glycine max L. Merr): the wild type (WT) and the herbicide-resistant D1 mutant STR7. This mutant also showed an increase in saturated fatty acids from thylakoid lipids. STR7 was more sensitive to photoinhibition under culture conditions. In vivo photoinhibition experiments in the presence of chloramphenicol, in vitro studies in isolated thylakoid membranes, and immunoblot analysis indicated that the process of light-induced degradation of the D1 protein was not involved in the response of STR7 to light. At growth temperature (24°C), the recovery rate of photoinhibited photosystem II (PSII) was slower in STR7 relative to WT. Photoinhibition and recovery were differentially affected by temperature in both cell lines. The rates of photoinhibition were faster in STR7 at any temperature below 27°C. The rates of PSII recovery from STR7 were more severely affected than those of WT at temperatures lower than 24°C. The photoinhibition and recovery rates of WT at 17°C mimicked those of STR7 at 24°C. In organelle translation studies indicated that synthesis and elongation of D1 were substantially similar in both cell lines. However, sucrose gradient fractionation of chloroplast membranes demonstrated that D1 and also other PSII proteins such as D2, OEE33, and LCHII had a reduced capability to incorporate into PSII to yield a mature assembled complex in STR7. This effect may become the rate-limiting step during the recovery of photoinhibited PSII and may explain the increased sensitivity to high light found in STR7. Our data may hint at a possible role of fatty acids from membrane lipids in the assembly and dynamics of PSII.Abbreviations DCBQ 2,6-Dichloro p-benzoquinone - DM Dodecyl--d-maltoside - DTT Dithiothreitol - HL High light - LHCII Light-harvesting complex II - LL Low light - OEE Oxygen-evolving extrinsic proteins - PAGE Polyacrylamide gel electrophoresis - PG Phosphatidylglycerol - PSII Photosystem II - Q_A and Q_B Secondary quinone electron acceptors from PSII - RC Reaction center - SDS Sodium dodecyl sulfate - WT Wild type     

Vitamin E or coenzyme Q10 administration is not fully advantageous for heart mitochondrial function in diabetic goto kakizaki rats

The heart is one of the organs affected during the later stages of diabetes. Mitochondrial function has already been proposed to be affected during the course of diabetes. Nevertheless, little information is known concerning the impact of antioxidants in heart mitochondria of a milder model for diabetes, such as the Goto-Kakizaki (GK) rat, where mitochondrial function appears ameliorated. The objective of this work was to test if injections of Vitamin E and Coenzyme Q10, alone and in combination, were able to modify mitochondrial performance in the hearts of GK rats. Several aspects of mitochondrial function were measured, such as the respiratory control ratio and the electric potential, as well as the mitochondrial accumulation of Vitamin E and Coenzymes Q9 and Q10. We observed that only Vitamin E appeared to have a positive impact on the mitochondrial phosphorylation efficiency and on mitochondrial performance, namely on the ability to generate the electric transmembrane potential in the presence of supra-physiological calcium concentrations. Vitamin E administration also increased the mitochondrial concentration of Coenzyme Q10. None of the treatments was able to reverse the diabetic phenotype in GK rats. We conclude that in this model of mild hyperglycemia, administration of antioxidants may have a marginal positive impact on mitochondrial function.     

Eurasian otters modify their trophic niche after the introduction of non-native prey in Mediterranean fresh waters

Biological invasions are a major driver behind disturbances in freshwater community structure. We investigated how the foraging strategy of the Eurasian otter Lutra lutra (L.) has responded to this change in a Mediterranean catchment of the Iberian Peninsula, over a 30-year time span (1980 vs. 2010). We found that, despite continuing to feed on a considerable amount of native fish, this carnivore has adapted its trophic niche to accommodate non-native species. Prior to the massive introductions of these new food items (1980), otters diversified their diet during the limiting season (i.e. summer drought). However, otters had largely incorporated non-native prey into their diet in 2010, with red-swamp crayfish being their main food resource, especially in the summer. This increased crayfish consumption reflects a narrowing of trophic niche during the summer drought in 2010. We discuss how this heavy specialisation may compromise the conservation of otters and their endemic fish prey.     

Intermittent Preventive Treatment of Malaria in Pregnancy with Mefloquine in HIV-Infected Women Receiving Cotrimoxazole Prophylaxis: A Multicenter Randomized Placebo-Controlled Trial

Background

Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended for malaria prevention in HIV-negative pregnant women, but it is contraindicated in HIV-infected women taking daily cotrimoxazole prophylaxis (CTXp) because of potential added risk of adverse effects associated with taking two antifolate drugs simultaneously. We studied the safety and efficacy of mefloquine (MQ) in women receiving CTXp and long-lasting insecticide treated nets (LLITNs).

Methods and Findings

A total of 1,071 HIV-infected women from Kenya, Mozambique, and Tanzania were randomized to receive either three doses of IPTp-MQ (15 mg/kg) or placebo given at least one month apart; all received CTXp and a LLITN. IPTp-MQ was associated with reduced rates of maternal parasitemia (risk ratio [RR], 0.47 [95% CI 0.27–0.82]; p = 0.008), placental malaria (RR, 0.52 [95% CI 0.29–0.90]; p = 0.021), and reduced incidence of non-obstetric hospital admissions (RR, 0.59 [95% CI 0.37–0.95]; p = 0.031) in the intention to treat (ITT) analysis. There were no differences in the prevalence of adverse pregnancy outcomes between groups. Drug tolerability was poorer in the MQ group compared to the control group (29.6% referred dizziness and 23.9% vomiting after the first IPTp-MQ administration). HIV viral load at delivery was higher in the MQ group compared to the control group (p = 0.048) in the ATP analysis. The frequency of perinatal mother to child transmission of HIV was increased in women who received MQ (RR, 1.95 [95% CI 1.14–3.33]; p = 0.015). The main limitation of the latter finding relates to the exploratory nature of this part of the analysis.

Conclusions

An effective antimalarial added to CTXp and LLITNs in HIV-infected pregnant women can improve malaria prevention, as well as maternal health through reduction in hospital admissions. However, MQ was not well tolerated, limiting its potential for IPTp and indicating the need to find alternatives with better tolerability to reduce malaria in this particularly vulnerable group. MQ was associated with an increased risk of mother to child transmission of HIV, which warrants a better understanding of the pharmacological interactions between antimalarials and antiretroviral drugs.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT 00811421","term_id":"NCT00811421"}}NCT 00811421; Pan African Clinical Trials Registry PACTR 2010020001813440 Please see later in the article for the Editors'' Summary     

Tuberculosis caused by Mycobacterium africanum: Knowns and unknowns

Tuberculosis (TB), one of the deadliest threats to human health, is mainly caused by 2 highly related and human-adapted bacteria broadly known as Mycobacterium tuberculosis and Mycobacterium africanum. Whereas M. tuberculosis is widely spread, M. africanum is restricted to West Africa, where it remains a significant cause of tuberculosis. Although several differences have been identified between these 2 pathogens, M. africanum remains a lot less studied than M. tuberculosis. Here, we discuss the genetic, phenotypic, and clinical similarities and differences between strains of M. tuberculosis and M. africanum. We also discuss our current knowledge on the immune response to M. africanum and how it possibly articulates with distinct disease progression and with the geographical restriction attributed to this pathogen. Understanding the functional impact of the diversity existing in TB-causing bacteria, as well as incorporating this diversity in TB research, will contribute to the development of better, more specific approaches to tackle TB.     

Sandhoff disease in Argentina: high frequency of a splice site mutation in the HEXB gene and correlation between enzyme and DNA-based tests for heterozygote detection

The level of -hexosaminidase activity in plasma and leukocytes and the frequency of three known HEXB mutations were studied in an Argentinean deme with high incidence of infantile Sandhoff disease. Two mutations were previously identified in one of two Sandhoff patients from the region, a splice mutation, IVS-2+1 GA, and a 4-bp deletion, CTTT_782–785. These mutations, and a 16kb deletion from the 5' end of the HEXB gene common in non-Argentineans, were screened in 9 Sandhoff patients (all unrelated), 24 obligate heterozygotes, 33 additional individuals belonging to families with affected members, and 64 randomly ascertained individuals from the high risk region. Of 31 independent alleles examined, including those of the two patients previously reported, 30 had the IVS-2 splice mutation and only the originally reported patient had the CTTT deletion. The 16-kb deletion was not observed. Further, among the 57 unaffected members of families with a previous history of Sandhoff disease, and absolute correlation was found between carrier diagnosis by enzyme assay of leukocytes and the DNA-based tests for mutation. One of the 64 controls was classified as a carrier by enzyme assay but did not have one of the three mutations screened. We conclude that a single mutation predominates in this Argentinean population and that the DNA-based test can be an effective supplement or alternative to enzyme-based testing.     

Mutation patterns and structural correlates in human immunodeficiency virus type 1 protease following different protease inhibitor treatments

Although many human immunodeficiency virus type 1 (HIV-1)-infected persons are treated with multiple protease inhibitors in combination or in succession, mutation patterns of protease isolates from these persons have not been characterized. We collected and analyzed 2,244 subtype B HIV-1 isolates from 1,919 persons with different protease inhibitor experiences: 1,004 isolates from untreated persons, 637 isolates from persons who received one protease inhibitor, and 603 isolates from persons receiving two or more protease inhibitors. The median number of protease mutations per isolate increased from 4 in untreated persons to 12 in persons who had received four or more protease inhibitors. Mutations at 45 of the 99 amino acid positions in the protease-including 22 not previously associated with drug resistance-were significantly associated with protease inhibitor treatment. Mutations at 17 of the remaining 99 positions were polymorphic but not associated with drug treatment. Pairs and clusters of correlated (covarying) mutations were significantly more likely to occur in treated than in untreated persons: 115 versus 23 pairs and 30 versus 2 clusters, respectively. Of the 115 statistically significant pairs of covarying residues in the treated isolates, 59 were within 8 A of each other-many more than would be expected by chance. In summary, nearly one-half of HIV-1 protease positions are under selective drug pressure, including many residues not previously associated with drug resistance. Structural factors appear to be responsible for the high frequency of covariation among many of the protease residues. The presence of mutational clusters provides insight into the complex mutational patterns required for HIV-1 protease inhibitor resistance.     

Cryptic species of Paracoccidioides brasiliensis: impact on paracoccidioidomycosis immunodiagnosis

We aimed to evaluate whether the occurrence of cryptic species of Paracoccidioides brasiliensis, S1, PS2, PS3 and Paracoccidioides lutzii, has implications in the immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen gp43 were found in culture filtrates of P. lutzii strains and this molecule appeared to be more variable within P. lutzii because the synonymous-nonsynonymous mutation rate was lower, indicating an evolutionary process different from that of the remaining genotypes. The production of gp43 also varied between isolates belonging to the same species, indicating that speciation events are important, but not sufficient to fully explain the diversity in the production of this antigen. The culture filtrate antigen AgEpm83, which was obtained from a PS3 isolate, showed large quantities of gp43 and reactivity by immunodiffusion assays, similar to the standard antigen (AgB-339) from an S1 isolate. Furthermore, AgEpm83 was capable of serologically differentiating five serum samples from patients from the Botucatu and Jundiaí regions. These patients had confirmed PCM but, were non-reactive to the standard antigen, thus demonstrating an alternative for serological diagnosis in regions in which S1 and PS2 occur. We also emphasise that it is not advisable to use a single antigen preparation to diagnose PCM, a disease that is caused by highly diverse pathogens.