Enantiomeric selectivity in behavioural and electrophysiological responses of Aedes aegypti and Culex quinquefasciatus mosquitoes

1-Octen-3-ol is a kairomone for many haematophagous insects including mosquitoes. Numerous studies have examined the effects of racemic 1-octen-3-ol; however, few studies have investigated the role of individual enantiomers in relation to mosquito attraction. In the present study, we investigated the behavioural and electrophysiological responses of two mosquito species, Aedes aegypti and Culex quinquefasciatus, to individual enantiomers and mixtures of 1-octen-3-ol, employing a laboratory Y-tube olfactometer and single sensillum recordings. The olfactory receptor neurons of both Ae. aegypti and Cx. quinquefasciatus had a significantly higher response to the (R)-1-octen-3-ol enantiomer compared to the (S)-1-octen-3-ol enantiomer at 10-9 g μl-1 to 10-6 g μl-1. Behaviourally, Ae. aegypti was more responsive to the (R)-1-octen-3-ol enantiomer, showing an increase in flight activity and relative attraction compared to Cx. quinquefasciatus. The (R)-1-octen-3-ol enantiomer caused an increase in activation for Cx. quinquefasciatus. However, the most notable effect was from an (R:S)-1-octen-3-ol mixture (84:16) that caused significantly more mosquitoes to sustain their flight and reach the capture chambers (demonstrated by a reduced non-sustained flight activity), suggesting that it may have a behaviourally excitatory effect. For Cx. quinquefasciatus, a reduced relative attraction response was also observed for all treatments containing the (R)-1-octen-3-ol enantiomer, either on its own or as part of a mixture, but not with the (S)-1-octen-3-ol enantiomer. This is the first time enantiomeric selectivity has been shown for Ae. aegypti using electrophysiology in vivo. The implications of these results for exploitation in mosquito traps are discussed.     

Analysis of various physiological salines for heart rate, CNS function, and synaptic transmission at neuromuscular junctions in Drosophila melanogaster larvae

Drosophila serves as a playground for examining the effects of genetic mutations on development, physiological function and behavior. Many physiological measures that address the effects of mutations require semi-intact or cultured preparations. To obtain consistent physiological recordings, cellular function needs to remain viable. Numerous physiological salines have been developed for fly preparations, with emphasis on nervous system viability. The commonly used saline drifts in pH and will cause an alteration in the heart rate. We identify a saline that maintains a stable pH and physiological function in the larval heart, skeletal neuromuscular junction, and ventral nerve cord preparations. Using these common assays, we screened various pH buffers of differing concentrations to identify optimum conditions. Buffers at 25 mM produce a stable heart rate with minimal variation in pH. Excitatory junction potentials evoked directly on larval muscles or through sensory-CNS-motor circuits were unaffected by at buffers at 25 mM. The salines examined did not impede the modulatory effect of serotonin on heart rate or neural activity. Together, our results indicate that the higher buffer concentrations needed to stabilize pH in HL3 hemolymph-like saline do not interfere with the acute function of neurons or cardiac myocytes.     

Production of exotoxins by Aeromonas spp. at 5 degrees C

The ability of 60 strains of Aeromonas to produce enterotoxin and haemolysin after cultivation at 5 degrees C for 7-10 d was investigated. The strains were isolated from lamb meat, offal, carcasses and faeces, and had previously been tested for their ability to produce these exotoxins at 37 degrees C. The results showed that some strains of Aeromonas hydrophila and A. sobria were capable of producing enterotoxin and haemolysin at 5 degrees C, but none of the A. caviae strains tested produced these two factors. Of the 30 A. hydrophila strains investigated 25 and 27 were enterotoxigenic and haemolytic respectively. Likewise, of the 24 A. sobria strains investigated 16 and 18 were enterotoxigenic and haemolytic respectively. The results indicate that certain strains of Aeromonas species, in particular A. hydrophila and A. sobria, are of potential public health significance in meats stored at refrigeration temperature.     

Strategies for Tobacco Control in India: A Systematic Review

Background

Tobacco control needs in India are large and complex. Evaluation of outcomes to date has been limited.

Aim

To review the extent of tobacco control measures, and the outcomes of associated trialled interventions, in India.

Methods

Information was identified via database searches, journal hand-searches, reference and citation searching, and contact with experts. Studies of any population resident in India were included. Studies where outcomes were not yet available, not directly related to tobacco use, or not specific to India, were excluded. Pre-tested proformas were used for data extraction and quality assessment. Studies with reliability concerns were excluded from some aspects of analysis. The Framework Convention on Tobacco Control (FCTC) was use as a framework for synthesis. Heterogeneity limited meta-analysis options. Synthesis was therefore predominantly narrative.

Results

Additional to the Global Tobacco Surveillance System data, 80 studies were identified, 45 without reliability concerns. Most related to education (FCTC Article 12) and tobacco-use cessation (Article 14). They indicated widespread understanding of tobacco-related harm, but less knowledge about specific consequences of use. Healthcare professionals reported low confidence in cessation assistance, in keeping with low levels of training. Training for schoolteachers also appeared suboptimal. Educational and cessation assistance interventions demonstrated positive impact on tobacco use. Studies relating to smoke-free policies (Article 8), tobacco advertisements and availability (Articles 13 and 16) indicated increasingly widespread smoke-free policies, but persistence of high levels of SHS exposure, tobacco promotions and availability—including to minors. Data relating to taxation/pricing and packaging (Articles 6 and 11) were limited. We did not identify any studies of product regulation, alternative employment strategies, or illicit trade (Articles 9, 10, 15 and 17).

Conclusions

Tobacco-use outcomes could be improved by school/community-based and adult education interventions, and cessation assistance, facilitated by training for health professionals and schoolteachers. Additional tobacco control measures should be assessed.     

The association of nutritional profile and prognosis of degenerative diseases associated with carbohydrate and lipid metabolism at high altitude of district Ziarat,Pakistan

Objective

In the present study the physiological parameters, their comparative analysis with carbohydrate and lipid metabolism were studied. This study suggests life style, environmental and genetic adaptations in the studied population.

Method

One hundred and ninety eight subjects were selected from different towns of District Ziarat. General characteristics of the population according to their nutritional habits including, age, body mass index(BMI), systolic blood pressure, diastolic blood pressure, glycemia, triglycerides, serum low density lipoprotein (LDL), high density lipoprotein (HDL), very low density lipoprotein (VLDL), triglycerides (TG) were measured.

Results

Mean cholesterol, LDL, VLDL and triglyceride values were significantly higher in men than women and the values increased with increasing age in both men and women. HDL and glucose values were significantly higher in females than males. In men with various nutritional groups such as A, B and C, the mean cholesterol (P < 0.001), LDL (P < 0.014), VLDL (P < 0.031) and triglyceride (P < 0.025) levels were significantly observed among comparable groups. However, in women with various nutritional groups such as A, B and C, the mean age (P < 0.047) and triglyceride values (P < 0.033) display statistically significant results.     

Salt-dependent binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and dipyrido[3,2-a:2',3'-c]phenazine to calf thymus DNA

The salt-dependent binding of racemic iron(II) mixed-ligand complex containing 1,10-phenanthroline (phen) and dipyrido[3,2-a:2',3'-c]phenazine (dppz), [Fe(phen)2(dppz)]2+ to calf thymus DNA (ct-DNA) has been characterized by UV-VIS spectrophotometric titration. The equilibrium binding constant (Kb) of the iron(II) complex to ct-DNA decreases with the salt concentration in the solution. The slope, SK=(deltalog Kb/deltalog [Na2+]) has been found to be 0.49, suggesting that, in addition to intercalation, considerable electrostatic interaction is also involved in the ct-DNA binding of [Fe(phen)2(dppz)]2+. The calculation of non-electrostatic binding constant (Kt(o)) based on polyelectrolyte theory has revealed that the non-electrostatic contribution to the total binding constant (Kb) increases significantly with the increase in [Na+] and reaches 36% at 0.1 M NaCl. On the other hand, the contribution of the non-electrostatic binding free energy (DeltaGt(o)) to the total binding free energy change (DeltaGo) is considerably large, i.e. 87% at [Na+]=0.1 M, suggesting that the stabilization of the DNA binding is mostly due to the contribution of non-electrostatic process. Moreover, the effect of specific ligand substitutions on DeltaGo has been rigorously evaluated using the quantity DeltaDeltaGt(o), i.e. the difference in DeltaGt(o) relative to that of the parent iron(II) complex, [Fe(phen)3]2+, indicating that each substitution of phen by dip and dppz contributes 7.5 and 17.5 kJ mol(-1), respectively to more favorable ct-DNA binding.     

Pregnenolone sulphate-independent inhibition of TRPM3 channels by progesterone

Transient Receptor Potential Melastatin 3 (TRPM3) is a widely expressed calcium-permeable non-selective cation channel that is stimulated by high concentrations of nifedipine or by physiological steroids that include pregnenolone sulphate. Here we sought to identify steroids that inhibit TRPM3. Channel activity was studied using calcium-measurement and patch-clamp techniques. Progesterone (0.01-10μM) suppressed TRPM3 activity evoked by pregnenolone sulphate. Progesterone metabolites and 17β-oestradiol were also inhibitory but the effects were relatively small. Dihydrotestosterone was an inhibitor at concentrations higher than 1μM. Corticosteroids lacked effect. Overlay assays indicated that pregnenolone sulphate, progesterone and dihydrotestosterone bound to TRPM3. In contrast to dihydrotestosterone, progesterone inhibited nifedipine-evoked TRPM3 activity or activity in the absence of an exogenous activator, suggesting a pregnenolone sulphate-independent mechanism of action. Dihydrotestosterone, like a non-steroid look-alike compound, acted as a competitive antagonist at the pregnenolone sulphate binding site. Progesterone inhibited endogenous TRPM3 in vascular smooth muscle cells. Relevance of TRPM3 or the progesterone effect to ovarian cells, which have been suggested to express TRPM3, was not identified. The data further define a chemical framework for competition with pregnenolone sulphate at TRPM3 and expand knowledge of steroid interactions with TRPM3, suggesting direct steroid binding and pregnenolone sulphate-independent inhibition by progesterone.     

Recovery of functionally active recombinant human phospholipid scramblase 1 from inclusion bodies using N-lauroyl sarcosine

Human phospholipid scramblase (hPLSCR1) is a transmembrane protein involved in rapid bidirectional scrambling of phospholipids across the plasma membrane in response to elevated intracellular calcium (Ca(2+)) levels. Overexpression of recombinant hPLSCR1 in Escherichia coli BL21 (DE3) leads to its deposition in inclusion bodies (IBs). N-lauroyl sarcosine was used to solubilize IBs and to recover functionally active hPLSCR1 from them. Protein was purified to homogeneity by nickel-nitrilotriacetic acid (Ni(2+)-NTA) affinity chromatography and was >98% pure. Functional activity of the purified protein was validated by in vitro reconstitution studies, ~18% of 7-nitrobenz-2-oxa-1, 3-diazol-4-yl-phosphatidylcholine (NBD-PC) phospholipids was translocated across the lipid bilayer in the presence of Ca(2+) ions. Far ultraviolet circular dichroism (UV-CD) studies reveal that the secondary structure of protein is predominantly an α-helix, and under nondenaturing conditions, the protein exists as a monomer. Here we describe a method to purify recombinant membrane protein with higher yield than previously described methods involving renaturation techniques.     

Nortriterpenoids from the roots of Paeonia emodi

Chemical investigation of chloroform–ethyl acetate extract from the roots of Paeonia emodi yielded four hitherto unknown noroleanane triterpenoids (1–4) together with four known compounds (5–8). Their structures were established by analysis of spectroscopic data. Compounds 1–8 were evaluated for cytotoxic activities against human cancer cell lines A549, HL-60, HCT116 and ZR-75-30. Compounds 1, 2, 3, 6 and 7 showed modest cytotoxicity against HL-60, HCT116 and ZR-75-30.