Pyrethroid-Acarophenax lacunatus interaction in suppressing the beetle Rhyzopertha dominica on stored wheat

Any biocontrol agent used against stored grain insects will have to interact with insecticides used as grain protectants due to their heavy use especially in tropical areas. Therefore, the interaction between the pyrethroid insecticides bifenthrin and deltamethrin and Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae), an egg parasite of the stored cereal pest Rhyzopertha dominica(F.) (Coleoptera: Bostrichidae), was assessed in a range of mite densities and insecticide doses for each compound. Despite the mite species presence on all insecticide doses, the lowest instantaneous rate of increase of A.lacunatus was recorded with the highest doses of insecticides. The presence of the biological control agent at all doses of both insecticides suggests its tolerance to these compounds. A. lacunatusshowed higher parasitism rate with bifenthrin than with deltamethrin indicating a higher selectivity of the first compound to the biocontrol agent. This revised version was published online in August 2006 with corrections to the Cover Date.     

Role of the prosegment of Fasciola hepatica cathepsin L1 in folding of the catalytic domain

The N-terminal propeptides of cysteine proteinases play regulatory roles in the folding and stability of their catalytic domains, as well as being potent and highly specific inhibitors of their parental mature enzymes. Cysteine proteinases play a major role in the biology of the parasitic trematode Fasciola hepatica; in particular, this organism secretes significant amounts of cathepsin L enzymes. The isolated propeptide of F. hepatica cathepsin L1 functioned as a chaperone for the mature enzyme in renaturation experiments. A double point mutation (N701/F721) within the GxNxFxD motif of the propeptide affected its conformation and markedly decreased its affinity for the mature enzyme. When this mutation was introduced into preprocathepsin L1 expressed in yeast, the secretion of active enzyme dropped dramatically. However, significant enzyme activity was recovered from the culture supernatants after denaturation and renaturation in the presence of native propeptide. Thus, the variant prosegment gave rise to an enzyme with altered conformation, which could be refolded to the active form with the assistance of the native propeptide.     

Repressor Mutant Forms of the Azospirillum brasilense NtrC Protein

The Azospirillum brasilense mutant strains FP8 and FP9, after treatment with nitrosoguanidine, showed a null Nif phenotype and were unable to use nitrate as their sole nitrogen source. Sequencing of the ntrC genes revealed single nucleotide mutations in the NtrC nucleotide-binding site. The phenotypes of these strains are discussed in relation to their genotypes.     

Sesquiterpenes and a phenylpropanoid from Cordia trichotoma

Two new secondary metabolites, the phenylpropanoid 3-(2',4',5'-trimethoxyphenyl)propanoic acid (1) and the sesquiterpene (+)-1beta,4beta,6alpha-trihydroxyeudesmane (2) were isolated from the heartwood of Cordia trichotoma Vell., along with the known sesquiterpenes (-)-1beta,4beta,7alpha-trihydroxyeudesmane (3) and (+)-1beta,4beta,11-trihydroxyoppositane (4). Their structures were elucidated by means of spectroscopic data interpretation, mainly 1D and 2D NMR and mass spectrometry.     

Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae); and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.     

The Absence of CYP3A5*3 Is a Protective Factor to Anticonvulsants Hypersensitivity Reactions: A Case-Control Study in Brazilian Subjects

Although aromatic anticonvulsants are usually well tolerated, they can cause cutaneous adverse drug reactions in up to 10% of patients. The clinical manifestations of the antiepileptics-induced hypersensitivity reactions (AHR) vary from mild skin rashes to severe cutaneous drug adverse reactions which are related to high mortality and significant morbidity. Genetic polymorphisms in cytochrome P450 genes are associated with altered enzymatic activity and may contribute to the risk of AHR. Here we present a case-control study in which we genotyped SNPs of CYP2C19, 2C9 and 3A5 of 55 individuals with varying severities of AHR, 83 tolerant, and 366 healthy control subjects from São Paulo, Brazil. Clinical characterization was based on standardized scoring systems and drug patch test. All in vivo investigation followed the ENDA (European Network of Drug Allergy) recommendations. Genotype was determined by real time PCR using peripheral blood DNA as a template. Of all 504 subjects, 65% were females, 45% self-identified as Afro-American, 38% as Caucasian and 17% as having non-African mixed ascendancy. Amongst 55 subjects with AHR, 44 had severe cutaneous drug adverse reactions. Of the 46 drug patch tests performed, 29 (63%) were positive. We found a strong association between the absence of CYP3A5*3 and tolerant subjects when compared to AHR (p = 0.0002, OR = 5.28 [CI95% 2.09–14.84]). None of our groups presented positive association with CYP2C19 and 2C9 polymorphisms, however, both SNPs contributed to separation of cases and tolerants in a Classification and Regression Tree. Our findings indicate that drug metabolism genes can contribute in the tolerability of antiepileptics. CYP3A5*3 is the most prevalent CYP3A5 allele associated with reduced enzymatic function. The current study provides evidence that normal CYP3A5 activity might be a protective factor to aromatic antiepileptics-induced hypersensitivity reactions in Brazilian subjects.     

HIV Drug Resistance Surveillance in Honduras after a Decade of Widespread Antiretroviral Therapy

Introduction

We assessed HIV drug resistance (DR) in individuals failing ART (acquired DR, ADR) and in ART-naïve individuals (pre-ART DR, PDR) in Honduras, after 10 years of widespread availability of ART.

Methods

365 HIV-infected, ART-naïve, and 381 ART-experienced Honduran individuals were enrolled in 5 reference centres in Tegucigalpa, San Pedro Sula, La Ceiba, and Choluteca between April 2013 and April 2015. Plasma HIV protease-RT sequences were obtained. HIVDR was assessed using the WHO HIVDR mutation list and the Stanford algorithm. Recently infected (RI) individuals were identified using a multi-assay algorithm.

Results

PDR to any ARV drug was 11.5% (95% CI 8.4–15.2%). NNRTI PDR prevalence (8.2%) was higher than NRTI (2.2%) and PI (1.9%, p<0.0001). No significant trends in time were observed when comparing 2013 and 2014, when using a moving average approach along the study period or when comparing individuals with >500 vs. <350 CD4+ T cells/μL. PDR in recently infected individuals was 13.6%, showing no significant difference with PDR in individuals with longstanding infection (10.7%). The most prevalent PDR mutations were M46IL (1.4%), T215 revertants (0.5%), and K103NS (5.5%). The overall ADR prevalence in individuals with <48 months on ART was 87.8% and for the ≥48 months on ART group 81.3%. ADR to three drug families increased in individuals with longer time on ART (p = 0.0343). M184V and K103N were the most frequent ADR mutations. PDR mutation frequency correlated with ADR mutation frequency for PI and NNRTI (p<0.01), but not for NRTI. Clusters of viruses were observed suggesting transmission of HIVDR both from ART-experienced to ART-naïve individuals and between ART-naïve individuals.

Conclusions

The global PDR prevalence in Honduras remains at the intermediate level, after 10 years of widespread availability of ART. Evidence of ADR influencing the presence of PDR was observed by phylogenetic analyses and ADR/PDR mutation frequency correlations.     

Loss of Expression of Reprimo,a p53-induced Cell Cycle Arrest Gene,Correlates with Invasive Stage of Tumor Progression and p73 Expression in Gastric Cancer

Reprimo (RPRM), a downstream effector of p53-induced cell cycle arrest at G2/M, has been proposed as a putative tumor suppressor gene (TSG) and as a potential biomarker for non-invasive detection of gastric cancer (GC). The aim of this study was to evaluate the epigenetic silencing of RPRM gene by promoter methylation and its tumor suppressor function in GC cell lines. Furthermore, clinical significance of RPRM protein product and its association with p53/p73 tumor suppressor protein family was explored. Epigenetic silencing of RPRM gene by promoter methylation was evaluated in four GC cell lines. Protein expression of RPRM was evaluated in 20 tumor and non-tumor matched cases. The clinical significance of RPRM association with p53/p73 tumor suppressor protein family was assessed in 114 GC cases. Tumor suppressor function was examined through functional assays. RPRM gene expression was negatively correlated with promoter methylation (Spearman rank r = -1; p = 0.042). RPRM overexpression inhibited colony formation and anchorage-independent growth. In clinical samples, RPRM gene protein expression was detected in 75% (15/20) of non-tumor adjacent mucosa, but only in 25% (5/20) of gastric tumor tissues (p = 0.001). Clinicopathological correlations of loss of RPRM expression were significantly associated with invasive stage of GC (stage I to II-IV, p = 0.02) and a positive association between RPRM and p73 gene protein product expression was found (p<0.0001 and kappa value = 0.363). In conclusion, epigenetic silencing of RPRM gene by promoter methylation is associated with loss of RPRM expression. Functional assays suggest that RPRM behaves as a TSG. Loss of expression of RPRM gene protein product is associated with the invasive stage of GC. Positive association between RPRM and p73 expression suggest that other members of the p53 gene family may participate in the regulation of RPRM expression.