Antifungal effect of different methyl and propyl paraben mixtures on the treatment of paper biodeterioration

With many important artistic works and documents made of paper, and thus susceptible to biodeterioration by fungi, research is required in an effort to replace toxic chemical products with other more benign ones. In this work the antifungal effect of methyl and propyl paraben mixtures at different concentrations was evaluated. The fungi used in the experiments were a Cladosporium species and Penicillium corylophilum, both of which are well known as paper-biodeteriorating fungi. The results demonstrate that a mixture of 0.5% methyl paraben and 1% propyl paraben, in 85% ethanolic solution, is the lowest concentration necessary to provide an efficient antifungal action. A deacidification agent, 5% calcium propionate, was added to this mixture to produce a multi-purpose formulation to treat acidification and fungal contamination of paper documents. Tests carried out on paper samples before and after application of this mixture showed only a minor increase in yellowing and a slight decrease in tensile strength, while substantially raising the pH, and thus the alkaline reserve, and also a slight increase in the percentage of deformation.     

Apparatus for measuring rat body volume: a methodological proposition.

We propose a communicating-vessels system to measure body volume in live rats through water level detection by hydrostatic weighing. The reproducibility, accuracy, linearity, and reliability of this apparatus were evaluated in two tests using previously weighed water or six aluminum cylinders of known volume after proper system calibration. The applicability of this apparatus to measurement of live animals (Wistar rats) was tested in a transversal experiment with five rats, anesthetized and nonanesthetized. We took 18 measurements of the volume under each condition (anesthetized and nonanesthetized), totaling 90 measurements. The addition of water volumes (50-700 ml) produced a regression equation with a slope of 1.0006 +/- 0.0017, intercept of 0.75 +/- 0.81 (R(2) = 0.99999, standard error of estimate = 0.58 ml), and bias of approximately 1 ml. The differences between cylinders of known volumes and volumes calculated by the system were <0.4 ml. Mean volume errors were 0.01-0.07%. Among the live models, the difference between the volumes obtained for anesthetized and nonanesthetized rats was 0.31 +/- 2.34 (SD) ml (n = 90). These data showed that animal movement does not interfere with the volume measured by the proposed apparatus, and neither anesthesia nor fur shaving is needed for this procedure. Nevertheless, some effort should be taken to eliminate air bubbles trapped in the apparatus or the fur. The proposed apparatus for measuring rat body volume is inexpensive and may be useful for a range of scientific purposes.     

Evidence of Field-Evolved Resistance of Spodoptera frugiperda to Bt Corn Expressing Cry1F in Brazil That Is Still Sensitive to Modified Bt Toxins

Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.     

Reference Ranges for Uterine Artery Pulsatility Index during the Menstrual Cycle: A Cross-Sectional Study

Background

Cyclic endometrial neoangiogenesis contributes to changes in local vascular patterns and is amenable to non-invasive assessment with Doppler sonography. We hypothesize that the uterine artery (UtA) impedance, measured by its pulsatility index (PI), exhibits a regular pattern during the normal menstrual cycle. Therefore, the main study objective was to derive normative new day-cycle-based reference ranges for the UtA-PI during the entire cycle from days 1 to 34 according to the isolated time effect and potential confounders such as age and parity.

Methods

From January 2009 to December 2012, a cross-sectional study of 1,821 healthy women undergoing routine gynaecological ultrasound was performed. The Doppler flow of the right and left UtA-PI was studied transvaginally by colour and pulsed Doppler imaging. The mean right and left values and the presence or absence of a bilateral protodiastolic notch were recorded. Reference intervals for the PI according to the cycle day were generated by classical linear regression.

Results

The majority of patients (97.5%) presented unilateral or bilateral UtA notches. The crude 5th, 50th, and 95th reference percentile curves of the UtA-PI at 1–34 days of the normal menstrual cycle were derived. In all curves, a progressive significant decrease occurred during the first 13 days, followed by an increase and recovery in the UtA-PI. The adjusted 5th, 50th, and 95th reference percentile curves for the effects of age and parity were also obtained. These two conditions generated an approximately identical UtA-PI pattern during the cycle, except with small but significant reductions at the temporal extremes.

Conclusions

The median, 5th, and the 95th percentiles of the UtA-PI decrease during the first third of the menstrual cycle and recover to their initial values during the last two thirds of the cycle. The rates of decrease and recovery depend significantly on age and parity.     

Variation in Plasmodium falciparum Histidine-Rich Protein 2 (Pfhrp2) and Plasmodium falciparum Histidine-Rich Protein 3 (Pfhrp3) Gene Deletions in Guyana and Suriname

Guyana and Suriname have made important progress in reducing the burden of malaria. While both countries use microscopy as the primary tool for clinical diagnosis, malaria rapid diagnostic tests (RDTs) are useful in remote areas of the interior where laboratory support may be limited or unavailable. Recent reports indicate that histidine-rich protein 2 (PfHRP2)-based diagnostic tests specific for detection of P. falciparum may provide false negative results in some parts of South America due to the emergence of P. falciparum parasites that lack the pfhrp2 gene, and thus produce no PfHRP2 antigen. Pfhrp2 and pfhrp3 genes were amplified in parasite isolates collected from Guyana and Suriname to determine if there were circulating isolates with deletions in these genes. Pfhrp3 deletions were monitored because some monoclonal antibodies utilized in PfHRP2-based RDTs cross-react with the PfHRP3 protein. We found that all 97 isolates from Guyana that met the inclusion criteria were both pfhrp2- and pfhrp3-positive. In Suriname (N = 78), 14% of the samples tested were pfhrp2-negative while 4% were pfhrp3-negative. Furthermore, analysis of the genomic region proximal to pfhrp2 and pfhrp3 revealed that genomic deletions extended to the flanking genes. We also investigated the population substructure of the isolates collected to determine if the parasites that had deletions of pfhrp2 and pfhrp3 belonged to any genetic subtypes. Cluster analysis revealed that there was no predominant P. falciparum population substructure among the isolates from either country, an indication of genetic admixture among the parasite populations. Furthermore, the pfhrp2-deleted parasites from Suriname did not appear to share a single, unique genetic background.     

A chalcid wasp acts chiefly as a hyperparasitoid by mostly using small uncommon hosts

Although ovipositing insects may predominantly use resources that lead to high offspring quality, exceptions to this rule have considerably aided understanding of oviposition decisions. We report the frequency of host species use by a solitary facultative hyperparasitoid, Brachymeria subrugosa Blanchard (Hymenoptera: Chalcididae). In our samples, the wasp attacks the large pupae of the moth Gonioterma indecora Zeller (Lepidoptera: Elachistidae), as well as the considerably smaller, and rarer, pupae of two of its other parasitoids. Consistent with conditional sex allocation models, the wasp produced mainly female offspring on the largest (moth) host, an unbiased sex ratio on the middle‐sized (parasitoid) host, and only males on the smallest (parasitoid) host. Adult offspring size was correlated with the size of the host attacked. These features strongly suggest that the two smaller, primary parasitoid, hosts produce lower‐quality offspring. Despite being more common, the proportion of hosts from which parasitoids emerged was lowest (14%) on the largest host species, and highest on the rarer middle‐sized (34%) and smallest (30%) hosts. This suggests that costs or constraints on attacking high‐quality primary hosts may be a selective force favouring the evolution of hyperparasitism.     

Experimental Evidence that Sexual Displays are Costly for Nest Survival

Nest predation is one of the most significant limitations for successful breeding of tropical passerines. Thus, parental strategies may include choosing appropriate nest sites and behaving in ways that minimize predation. Habitat characteristics that may influence nest success include degree of nest concealment, proximity to habitat edge, plant architecture as well as several others cited in the literature. However, few studies have examined display behavior as a factor that could also influence nest survival. We experimentally tested whether sexual motor displays served as a cue for visually oriented predators to locate artificial nests in a population of blue‐black grassquits Volatinia jacarina, a Neotropical passerine that exhibits a complex sexual display and is subjected to elevated rates of nest predation. We also evaluated the effect of nest substrate on survival. Predation rate was higher for nests within territories of displaying males relative to areas without displaying males and for nests placed in shrubs relative to grasses. Predation increased sharply in the third experimental replicate, at the end of the breeding season, which suggests that predators may develop a search image for nests or may become more abundant during specific periods of the season. Avian predators appear to be the most important nest predators. Results suggest that there may be a trade‐off between the increase in fitness derived from sexual displays of males to attract potential mates and the decrease owing to predation of active nests within their territories.     

Sylvatic and peridomestic populations of Triatoma pseudomaculata are not significantly structured by habitat,as revealed by two genetic markers

Chagas disease remains a public health concern in Brazil and other Latin American countries, mainly due to the potential domiciliation of native triatomine species. We analyzed the genetic variability of Triatoma pseudomaculata in sylvatic and peridomestic ecotopes throughout three localities in the northeastern state of Bahia, Brazil. We studied polymorphisms generated by random amplified polymorphic DNA (RAPD) and isoenzyme electrophoresis analyses. Based on RAPD analysis, each specimen was assigned to one of three genetic clusters. Although all sylvatic specimens from one locality were grouped into the same cluster, sylvatic and peridomestic specimens from the other two localities were broadly distributed between the remaining two clusters, suggesting that geographic population structuring was not occurring. Furthermore, isoenzyme analysis suggested that distinct populations were in Hardy‐Weinberg equilibrium. Low statistical values for Wright's Fst index also supported the absence of population structuring and suggested the occurrence of panmixia. We conclude that genetic flow occurs between sylvatic and peridomestic T. pseudomaculata populations, probably as a consequence of passive and active dispersion of the insects, associated with deforestation and anthropic transformations.