Discrepancies between Aedes aegypti identification in the field and in the laboratory after collection with a sticky trap

Currently, sticky traps are regularly employed to assist in the surveillanceof Aedes aegypti infestation. We tested two alternativeprocedures for specimen identification performed by local health agents: directly inthe field, as recommended by certain manufacturers, or after transportation to thelaboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly duringone year in four geographically representative Brazilian municipalities. When thesame samples were inspected in the field and in the laboratory, large differenceswere noted in the total number of mosquitoes recorded and in the number of specimensidentified as Ae. aegypti by both procedures. Although fieldidentification has the potential to speed vector surveillance, these results point touncertainties in the evaluated protocol.     

The importance of the Abn2 calcium cluster in the endo-1,5-arabinanase activity from Bacillus subtilis

Arabinanase is a glycosyl hydrolase that is able to cleave the glycosidic bonds of α-1,5-l-arabinan, releasing arabino-oligosaccharides and l-arabinose. The enzyme has two domains, an N-terminal catalytic domain with a characteristic β-propeller fold and a C-terminal domain whose function is unknown. A calcium ion, located near the catalytic site, serves to stabilize the N-terminal domain, but it has also been proposed to play a key role in the enzyme mechanism. The present work describes the structure of an inactive mutant of the wild-type enzyme (H318Q) and in which the calcium ion has been adventitiously replaced by nickel. These structural studies, together with functional and modelling studies, clearly support the role of the calcium ion in the overall reaction mechanism.     

Long-Term CO2 Variability in Two Shallow Tropical Lakes Experiencing Episodic Eutrophication and Acidification Events

Here we report the long-term (13-year) dynamics of surface pCO₂ and its response to episodic eutrophication and acidification events in two contrasting tropical coastal lakes, one clear-water and the other humic. A short-term nutrient addition experiment was also conducted in mesocosms in the humic lake where in situ eutrophication was moderate. Our objective was to elucidate the response of pCO₂ to interannual changes in key limnological conditions, such as nutrient concentrations and pH. The humic waters showed a median pCO₂ almost ninefold higher across the 13-year study than the clear waters, supporting pCO₂ values about tenfold above atmospheric equilibrium. Eutrophication of the clear-water lake resulted in a decrease in pCO₂ to median values below atmospheric equilibrium, producing a strong sink for atmospheric CO₂. In contrast, pCO₂ increased by over tenfold in both lakes during the acidification phase, resulting in very large CO₂ emissions to the atmosphere. Experimental nutrient additions in the humic lake showed a strong persistence of high pCO₂. The extreme variability in pCO₂ observed here might be a characteristic of tropical lakes and may have important consequences for regional carbon budgets.     

Pasteurella canis infection in a non-human primate black-tailed marmoset (Mico melanurus)—A case report

This study reports the pathological and microbiological findings of pneumonia in a Mico melanurus caused by Pasteurella canis, confirmed for molecular analyses. It demonstrated the importance that wild species represent in the epidemiology of pasteurellosis in anthropic environments, when inserted into urban areas.     

Simplified 2,4-dinitrophenylhydrazine spectrophotometric assay for quantification of carbonyls in oxidized proteins

This work proposes a modification of the 2,4-dinitrophenylhydrazine (DNPH) spectrophotometric assay commonly used to evaluate the concentration of carbonyl groups in oxidized proteins. In this approach NaOH is added to the protein solution after the addition of DNPH, shifting the maximum absorbance wavelength of the derivatized protein from 370 to 450 nm. This reduces the interference of DNPH and allows the direct quantification in the sample solution without the need for the precipitation, washing, and resuspension steps that are carried out in the traditional DNPH method. The two methods were compared under various conditions and are statistically equivalent.     

Protein kinase C modulates synaptic vesicle acidification in a ribbon type nerve terminal in the retina

The driving force for neurotransmitter accumulation into synaptic vesicles is provided by the generation of a transmembrane electrochemical gradient (DeltamicroH+) that has two components: a chemical gradient (DeltapH, inside acidic) and an electrical potential across the vesicular membrane (DeltaPsi, inside positive). This gradient is generated in situ by the electrogenic vacuolar H(+)-ATPase, which is responsible for the acidification and positive membrane potential of the vesicle lumen. Here, we investigate the modulation of vesicle acidification by using the acidic-organelle probe LysoTracker and the pH-sensitive probe LysoSensor at goldfish Mb-type bipolar cell terminals. Since phosphorylation can modulate secretory granule acidification in neuroendocrine cells, we investigated if drugs that affect protein kinases modulate LysoTracker staining of bipolar cell terminals. We find that protein kinase C (PKC) activation induces an increase in LysoTracker-fluorescence. By contrast, protein kinase A (PKA) or calcium/calmodulin kinase II (CaMKII) activation or inhibition did not change LysoTracker-fluorescence. Using a pH-dependent fluorescent dye (LysoSensor) we show that the PKC activation with PMA induces an increase in LysoSensor-fluorescence, whereas the inactive analog 4alpha-PMA was unable to cause the same effect. This increase induced by PMA was blocked by PKC inhibitors, calphostin C and staurosporine. These results suggest that phosphorylation by PKC may increase synaptic vesicle acidification in retinal bipolar cells and therefore has the potential to modulate glutamate concentrations inside synaptic vesicles.     

Rat LINE1: The origin and evolution of a family of long interspersed middle repetitive DNA elements

Summary We present approximately 7.0 kb of composite DNA sequence of a long interspersed middle repetitive element (LINE1) present in high copy number in the rat genome. The family of these repeats, which includes transcribing members, is the rat homologue of the mouse MIF-Bam-R and human Kpn I LINEs. Sequence alignments between speciments from these three species define the length of a putative unidentified open reading frame, and document extensive recombination events that, in conjunction with retroposition, have generated this large family of pseudogenes and pseudogene fragments. Comparative mapping of truncated elements indicates that a specific endonucleolytic activity might bei involved in illegitimate (nonhomologous) recombination events. Sequence divergence analyses provide insights into the origin and molecular evolution of these elements.     

Molecular basis for redox-Bohr and cooperative effects in cytochrome c3 from Desulfovibrio desulfuricans ATCC 27774: crystallographic and modeling studies of oxidized and reduced high-resolution structures at pH 7.6

The tetraheme cytochrome c3 is a small metalloprotein with ca. 13,000 Da found in sulfate-reducing bacteria, which is believed to act as a partner of hydrogenase. The three-dimensional structure of the oxidized and reduced forms of cytochrome c3 from Desulfovibrio desulfuricans ATCC 27774 at pH 7.6 were determined using high-resolution X-ray crystallography and were compared with the previously determined oxidized form at pH 4.0. Theoretical calculations were performed with both structures, using continuum electrostatic calculations and Monte Carlo sampling of protonation and redox states, in order to understand the molecular basis of the redox-Bohr and cooperativity effects related to the coupled transfer of electrons and protons. We were able to identify groups that showed redox-linked conformational changes. In particular, Glu61, His76, and propionate D of heme II showed important contributions to the redox-cooperativity, whereas His76, propionate A of heme I, and propionate D of heme IV were the key residues for the redox-Bohr effect. Upon reduction, an important movement of the backbone region surrounding hemes I and II was also identified, that, together with a few redox-linked conformational changes in side-chain residues, results in a significant decrease in the solvent accessibility of hemes I and II.