Assessment of therapeutic responses to gametocytocidal drugs in Plasmodium falciparum malaria

Background

Effective mating between laboratory-reared males and wild females is paramount to the success of vector control strategies aiming to decrease disease transmission via the release of sterile or genetically modified male mosquitoes. However mosquito colonization and laboratory maintenance have the potential to negatively affect male genotypic and phenotypic quality through inbreeding and selection, which in turn can decrease male mating competitiveness in the field. To date, very little is known about the impact of those evolutionary forces on the reproductive biology of mosquito colonies and how they ultimately affect male reproductive fitness.

Methods

Here several male reproductive physiological traits likely to be affected by inbreeding and selection following colonization and laboratory rearing were examined. Sperm length, and accessory gland and testes size were compared in male progeny from field-collected females and laboratory strains of Anopheles gambiae sensu stricto colonized from one to over 25 years ago. These traits were also compared in the parental and sequentially derived, genetically modified strains produced using a two-phase genetic transformation system. Finally, genetic crosses were performed between strains in order to distinguish the effects of inbreeding and selection on reproductive traits.

Results

Sperm length was found to steadily decrease with the age of mosquito colonies but was recovered in refreshed strains and crosses between inbred strains therefore incriminating inbreeding costs. In contrast, testes size progressively increased with colony age, whilst accessory gland size quickly decreased in males from colonies of all ages. The lack of heterosis in response to crossing and strain refreshing in the latter two reproductive traits suggests selection for insectary conditions.

Conclusions

These results show that inbreeding and selection differentially affect reproductive traits in laboratory strains overtime and that heterotic ‘supermales’ could be used to rescue some male reproductive characteristics. Further experiments are needed to establish the exact relationship between sperm length, accessory gland and testes size, and male reproductive success in the laboratory and field settings.     

Disintegration of Dung Pats from Cattle Treated with the Ivermectin Anthelmintic Bolus,or the Biocontrol Agent Duddingtonia flagrans

An experiment was performed during the grazing seasons of 1998, 1999 and 2000 to study the influence of the antiparasitic drug ivermectin and the nematophagous fungus Duddingtonia flagrans on cattle dung disintegration. The faeces originated from groups of animals that were part of a separate grazing experiment where different control strategies for nematode parasite infections were investigated. Each group consisted of 10 first-season grazing cattle that were either untreated, treated with the ivermectin sustained-release bolus, or fed chlamydospores of D. flagrans. Faeces were collected monthly on 4 occasions and out of pooled faeces from each group, 4 artificial 1 kg dung pats were prepared and deposited on nylon mesh on an enclosed pasture and protected from birds. The position of the new set of pats was repeated throughout the 3 years of the study. Each year, the dung pats were weighed 4, 6, 8 and 10 weeks after deposition and immediately afterwards replaced to their initial positions.

Results showed that there was no difference in faecal pat disintegration between groups. However, the time-lag between deposition and complete disintegration of the faeces varied significantly between deposition occasions. Dung pats disappeared within 2 weeks (visual observation) when subjected to heavy rainfall early after deposition, whereas an extended dry period coincided with faeces still remaining 12 months after deposition.

     

How weekly monitoring variables influence players’ and teams’ match performance in elite futsal players

This study aimed to investigate how weekly training load constrains the performance of players and teams in official futsal competitions. Data from a professional male team were collected during two seasons (46 weeks). The applied monitoring system analysed the training load (as measured by session perceived exertion, sRPE), the total recovery status (TQR), the well-being score (WBs) and the variability of neuromuscular performance during each week (CMJ-cv). In addition, the performance was assessed for all the matches. A path analysis model was performed to test the associations across variables. Results from the path analysis model revealed that it explains 31% of the teams’ performance. In general, the results show that previous team performance has no significant effects on the training week. A significant negative relationship was found between CMJ-cv and match performance (β = -.34; CI95% -.359 to -.070), as well as a significant negative relationship between players’ match performance and the team’s match performance (β = -.55; CI95% -.292 to .740). Regarding indirect effects, only a negative association between CMJ-cv and team match performance via players’ match performance (β = -.19; CI95% -.342 to -.049) was identified. The small variation of the weekly CMJ (CMJ-cv) seems to be a key variable to monitor and explain both player and team performance. Based on this model, and only looking at the physical variables, it was possible to explain 31% of the team’s performance. Longitudinal and multi-team studies should be conducted to integrate other technical, tactical and psychological variables that allow the level of understanding of players’ and teams’ performance to be improved.     

Chloroplast Proteome of <Emphasis Type="Italic">Nicotiana benthamiana</Emphasis> Infected by Tomato Blistering Mosaic Virus

Tymovirus is a genus of plant pathogenic viruses that infects several dicotyledonous plants worldwide, causing serious diseases in economically important crops. The known cytopathic effect on the host cell organelles involves chloroplast membrane deformation and the induction of vesicles in its periphery. These vesicles are known to be the location where tymoviral genomic RNA replication occurs. Tomato blistering mosaic virus (ToBMV) is a tymovirus recently identified in tomato plants in Brazil, which is able to infect several other plants, including tobacco. In this work, we investigated the chloroplast proteomic profile of ToBMV-infected N. benthamiana using bidimensional electrophoresis (2-DE) and mass spectrometry, aiming to study the virus-host interaction related to the virus replication and infection. A total of approximately 200 spots were resolved, out of which 36 were differentially abundant. Differential spots were identified by mass spectrometry including photosynthesis-related and defense proteins. We identified proteins that may be targets of a direct interaction with viral proteins, such as ATP synthase β subunit, RNA polymerase beta-subunit, 50S ribosomal protein L6 and Trigger factor-like protein. The identification of these candidate proteins gives support for future protein–protein interaction studies to confirm their roles in virus replication and disease development.     

Vulnerability to longline fisheries of three hammerhead shark Sphyrna species in the south‐western and equatorial Atlantic Ocean

Catch and effort data from 29 418 longline sets from Brazilian tuna longline vessels operating in the south‐western and equatorial Atlantic Ocean between 2004 and 2011 were analysed to investigate the distribution, catch rate and size of three species of hammerhead sharks (Sphyrna lewini, Sphyrna mokarran and Sphyrna zygaena). During that period, 6172 hammerhead sharks were caught. Among the elasmobranchs, the highest percentage of hammerhead sharks were caught in 2007, when they accounted for 3·90% of the group, while the lowest value of 0·40% was recorded in 2010. In general, the spatial distribution of the mean catch per unit effort (CPUE) by years and quarters showed a trend of higher catches near the equatorial region and in southern Brazil. The nominal mean CPUE was 0·12 Sphyrna spp. 1000⁻¹ hooks, with the highest value being recorded in 2007 (0·30 Sphyrna spp. 1000⁻¹ hooks). The standardized yearly CPUE estimated by a generalized linear model assuming a zero inflated negative binomial (ZINB) distribution were not much different from nominal values. Of the 205 sexed specimens, 117 were females and 88 were males, resulting in a sex ratio with a predominance of females (1·30:1·00), although not statistically significant. The total length of females ranged from 1200 to 2800 mm and of males from 1100 to 3100 mm. Juvenile hammerhead sharks represented 82 and 54% of the sexed female and male specimens, respectively.     

Metabolism of Ethionine in Ethionine-Sensitive and Ethionine-Resistant Cells of the Enteric Yeast Candida slooffii

In a defined medium with added ethionine plus low methionine, phenylalanine, tryptophan, tyrosine, adenine, and additional methionine reversed inhibition of the enteric yeast Candida slooffii by ethionine. Isoleucine and 7-methylguanine restored half-maximal growth. Choline but not triethylcholine inhibited C. slooffii. 6-Mercaptopurine reversed ethionine inhibition and also synergistic inhibition by ethionine plus choline. Protection against ethionine by adenine plus aromatics was also evident with log-phase cells in the absence of methionine. Incorporation of ethionine-ethyl-1-(14)C by resting cells was partially inhibited by aromatic amino acids and methionine. Ethionine depressed incorporation of (3)H-phenylalanine but not of (3)H-adenine. Ethionine-resistant mutants were isolated which incorporated ethionine efficiently and degraded it to yet unidentified substances not including 5'-ethylthioadenosine. Ethionine-sensitive cells accumulated more S-adenosylethionine (SAE) than resistant mutants. Adenine was a good precursor of SAE. Radioactivity from ethionine-ethyl-1-(14)C was recovered from cell fractions of ethionine-sensitive cells with the following distribution: cold trichloroacetic acid-soluble > hot trichloroacetic acid-insoluble > lipids > deoxyribonucleic acid > ribonucleic acid. Total radioactivity recovered from ethionine-sensitive cells was twice as much as that from ethionine-resistant mutants.     

Characterization of Fonsecaea pedrosoi melanin.

The constituents of the melanin complex from mycelial forms of Fonsecaea pedrosoi were partially characterized. The pigment was mainly accumulated on large alkali-extractable, electron-dense cytoplasmic bodies (melanosomes) and, apparently, on the outer layer of the cell wall as external deposits within verrucose outgrowths. Using electron microscopy and Thiéry's periodate/thiosemicarbazide/silver proteinate staining method, glycogen-like particles were also detected at the periphery of the cells. Melanin constituents comprised aromatic and aliphatic/glycosidic structures with a predominance of the latter. Infrared spectra showed the presence of hydroxyl, carbonyl and carboxyl groups. The aliphatic/glycosidic moiety consisted of fatty acids and polysaccharides with protein, in a ratio protein/polysaccharide 1:15. Rhamnose, mannose, galactose and glucose (in the ratio 1:2:4:3.5) were the constituents of the polysaccharide. Lipid components included even-numbered, saturated and unsaturated fatty acids (in the ratio 2:1) ranging from C16 to C18. Palmitic and oleic acids were the prominent fatty acids. Aspartic and glutamic acids, leucine, glycine and alanine were the major amino acids. Non-pigmented cells of F. pedrosoi were studied for comparison with the pigmented forms: they did not accumulate acid-insoluble precursors of melanin.     

Complement-mediated lysis of Trypanosoma cruzi trypomastigotes by human anti-alpha-galactosyl antibodies.

Antibodies that lyse trypomastigotes in a complement-mediated reaction are believed to be the main participants in the protection against virulent Trypanosoma cruzi. Antibodies with a specificity for alpha-galactosyl-containing determinants--generally called antiGal--were studied to determine their role in the lysis of trypomastigote forms. The titers of antiGal markedly increase in Chagas's disease. In the present study we demonstrate binding of this antibody to T. cruzi and the complement-mediated lysis of trypomastigotes by antiGal. Lysis of metacyclic trypomastigotes by whole Chagasic (Ch) serum or isolated antiGal fractions was equally inhibited by alpha- but not by beta-galactosides. Most of the lytic power of the Ch antiGal as well as of the whole Ch serum was removed by absorption on Synsorb-linked Gal alpha 1, 3Gal beta 1, 4GlcNAc followed by rabbit erythrocyte absorption. The Ch antiGal had a lower affinity for melibiose bound to agarose than for the trisaccharide linked to Synsorb, and was several times more effective in the immunolysis of trypomastigotes than the corresponding antiGal from normal human serum. Lytic antibodies were partly absorbed by Serratia marcescens but not by Escherichia coli O111. A human volunteer immunized with an S. marcescens vaccine elicited a specific antiGal response that was lytic to trypomastigotes (70% lysis). We suggest that in vivo high-affinity antiGal antibody clones, as occur in Ch patients, may significantly contribute to the destruction of the parasite, whereas low-affinity antiGal clones are much less effective in the protection against T. cruzi infection.