The Association between Multiple Sources of Information and Risk Perceptions of Tuberculosis,Ntcheu District,Malawi

Background

Tuberculosis (TB) is one of the main causes of death in developing countries. Awareness and perception of risk of TB could influence early detection, diagnosis and care seeking at treatment centers. However, perceptions about TB are influenced by sources of information.

Aim

This study aimed to determine the association between multiple sources of information, and perceptions of risk of TB among adults aged 18–49 years.

Methods

A cross-sectional study was conducted in Ntcheu district in Malawi. A total of 121 adults were sampled in a three-stage simple random sampling technique. Data were collected using a structured questionnaire. Perceptions of risk were measured using specific statements that reflected common myths and misconceptions. Low risk perception implied a person having strong belief in myths and misconceptions about TB and high risk perception meant a person having no belief in myths or misconceptions and demonstrated understanding of the disease.

Results

Females were more likely to have low risk perceptions about TB compared to males (67.7% vs. 32.5%, p = 0.01). The higher the household asset index the more likely an individual had higher risk perceptions about TB (p = 0.006). The perception of risk of TB was associated with sources of information (p = 0.03). Use of both interpersonal communication and mass media was 2.8 times more likely to be associated with increased perception of risk of TB (Odds Ratio [OR] = 2.8; 95% Confidence interva1[CI]: 3.1–15. 6; p = 0.01). After adjusting for sex and asset ownership, use of interpersonal communication and mass media were more likely to be associated with higher perception of risk of TB (OR, 2.0; 95% CI: 1.65–10.72; p = 0.003) compared with interpersonal communication only (OR 1.6, 95%; CI: 1.13–8.98, p = 0.027).

Conclusion

The study found that there was association between multiple sources of information, and higher perceptions of risk of TB among adults aged 18–49 years.     

Sex allocation theory reveals a hidden cost of neonicotinoid exposure in a parasitoid wasp

Sex allocation theory has proved to be one the most successful theories in evolutionary ecology. However, its role in more applied aspects of ecology has been limited. Here we show how sex allocation theory helps uncover an otherwise hidden cost of neonicotinoid exposure in the parasitoid wasp Nasonia vitripennis. Female N. vitripennis allocate the sex of their offspring in line with Local Mate Competition (LMC) theory. Neonicotinoids are an economically important class of insecticides, but their deployment remains controversial, with evidence linking them to the decline of beneficial species. We demonstrate for the first time to our knowledge, that neonicotinoids disrupt the crucial reproductive behaviour of facultative sex allocation at sub-lethal, field-relevant doses in N. vitripennis. The quantitative predictions we can make from LMC theory show that females exposed to neonicotinoids are less able to allocate sex optimally and that this failure imposes a significant fitness cost. Our work highlights that understanding the ecological consequences of neonicotinoid deployment requires not just measures of mortality or even fecundity reduction among non-target species, but also measures that capture broader fitness costs, in this case offspring sex allocation. Our work also highlights new avenues for exploring how females obtain information when allocating sex under LMC.     

Mechanism of sulfide-quinone reductase investigated using site-directed mutagenesis and sulfur analysis

Biological sulfide oxidation is a reaction occurring in all three domains of life. One enzyme responsible for this reaction in many bacteria has been identified as sulfide:quinone oxidoreductase (SQR). The enzyme from Rhodobacter capsulatus is a peripherally membrane-bound flavoprotein with a molecular mass of approximately 48 kDa, presumably acting as a homodimer. In this work, SQR from Rb. capsulatus has been modified with an N-terminal His tag and heterologously expressed in and purified from Escherichia coli. Three cysteine residues have been shown to be essential for the reductive half-reaction by site-directed mutagenesis. The catalytic activity has been nearly completely abolished after mutation of each of the cysteines to serine. A decrease in fluorescence on reduction by sulfide as observed for the wild-type enzyme has not been observed for any of the mutated enzymes. Mutation of a conserved valine residue to aspartate within the third flavin-binding domain led to a drastically reduced substrate affinity, for both sulfide and quinone. Two conserved histidine residues have been mutated individually to alanine. Both of the resulting enzymes exhibited a shift in the pH dependence of the SQR reaction. Polysulfide has been identified as a primary reaction product using spectroscopic and chromatographic methods. On the basis of these data, reaction mechanisms for sulfide-dependent reduction and quinone-dependent oxidation of the enzyme and for the formation of polysulfide are proposed.     

Effects of injury and progesterone treatment on progesterone receptor and progesterone binding protein 25-Dx expression in the rat spinal cord

Progesterone provides neuroprotection after spinal cord injury, but the molecular mechanisms involved in this effect are not completely understood. In this work, expression of two binding proteins for progesterone was studied in intact and injured rat spinal cord: the classical intracellular progesterone receptor (PR) and 25-Dx, a recently discovered progesterone membrane binding site. RT-PCR was employed to determine their relative mRNA levels, whereas cellular localization and relative protein levels were investigated by immunocytochemistry. We observed that spinal cord PR mRNA was not up-regulated by estrogen in contrast to what is observed in many brain areas and in the uterus, but was abundant as it amounted to a third of that measured in the estradiol-stimulated uterus. In male rats with complete spinal cord transection, levels of PR mRNA were significantly decreased, while those of 25-Dx mRNA remained unchanged with respect to control animals. When spinal cord-injured animals received progesterone treatment during 72 h, PR mRNA levels were not affected and remained low, whereas 25-Dx mRNA levels were significantly increased. Immunostaining of PR showed its intracellular localization in both neurons and glial cells, whereas 25-Dx immunoreactivity was localized to cell membranes of dorsal horn and central canal neurons. As the two binding proteins for progesterone differ with respect to their response to lesion, their regulation by progesterone, their cellular and subcellular localizations, their functions may differ under normal and pathological conditions. These observations point to a novel and potentially important role of the progesterone binding protein 25-Dx after injury of the nervous system and suggest that the neuroprotective effects of progesterone may not necessarily be mediated by the classical progesterone receptor but may involve distinct membrane binding sites.     

HPLC-NMR/HPLC-MS analysis of the bark extract of Stauranthus perforatus

A combination of HPLC-MS and HPLC-NMR techniques has been used to analyse the cytotoxic fractions of the dichloromethane extract of bark of Stauranthus perforatus. Six furanocoumarins (byakangelicol, heraclenin, heraclenol, imperatorin, isopimpinellin and xanthotoxin) and nine quinoline alkaloids (two known compounds, veprisine and 5-hydroxy-1-methyl-2-phenyl-4-quinolone, along with seven novel compounds, stauranthine, 3',4'-dihydroxy-3',4'-dihydroveprisine, 3',4'-dihydroxy-3',4'-dihydrostauranthine, 3',6'-dihydroxy-3',6'-dihydroveprisine, 3',6'-dihydroxy-3',6'-dihydrostauranthine, 6'-hydroxy-3'-ketoveprisine and 6'-hydroxy-3'-ketostauranthine) have been identified in the fractions.     

Cu(II) ion interaction with teicoplanin-vancomycin’s analog

Teicoplanin, a member of the “last chance” antibiotic family has a similar structure and the same mechanism of action as parent drug vancomycin, which is proved to be an effective binder of Cu(II) ions. However, the potentiometric and spectroscopic studies (UV-visible, CD, NMR) have shown that the modification of the N-terminal structure of the peptide backbone in teicoplanin affects considerably the binding ability towards Cu(II) ions. While vancomycin forms almost instantly the stable 3 N complex species involving the N-terminal and two amide nitrogen donors, in case of teicoplanin only two nitrogen donors derived from the N-terminal amino group and adjacent peptide bond are coordinated to Cu(II) ion within the whole pH range studied. The major factor influencing the binding mode is most likely the structure of the N-terminus of the peptide unit in the antibiotic ligand.     

Effect of FKBP65, a putative elastin chaperone, on the coacervation of tropoelastin in vitro

FKBP65 is a protein of the endoplasmic reticulum that is relatively abundant in elastin-producing cells and is associated with tropoelastin in the secretory pathway. To test an earlier suggestion by Davis and co-workers that FKBP65 could act as an intracellular chaperone for elastin, we obtained recombinant FKBP65 (rFKBP65) by expressing it in E.?coli and examined its effect on the coacervation characteristics of chicken aorta tropoelastin (TE) using an in vitro turbidimetric assay. Our results reveal that rFKBP65 markedly promotes the initiation of coacervation of TE without significantly affecting the temperature of onset of coacervation. This effect shows saturation at a 1:2 molar ratio of TE to rFKBP65. By contrast, FKBP12, a peptidyl prolyl isomerase, has a negligible effect on TE coacervation. Moreover, the effect of rFKBP65 on TE coacervation is unaffected by the addition of rapamycin, an inhibitor of peptidyl prolyl isomerase (PPIase) activity. These observations rule out the involvement of the PPIase activity of rFKBP65 in modulating the coacervation of TE. Additional experiments using a polypeptide model of TE showed that rFKBP65, while promoting coacervation, may retard the maturation of this model polypeptide into larger aggregates. Based on these results, we suggest that FKBP65 may act as an elastin chaperone in vivo by controlling both the coacervation and the maturation stages of its self-assembly into fibrils.     

Internal desynchronization of circadian rhythms and tolerance of shift work

Fifteen male subjects including 12 shift workers (oil refinery operators) volunteered to document circadian rhythms in sleep-wake, grip strength of both hands, peak expiratory flow, heart rate, self-rated drowsiness, fatigue and attention. Each of these variables was measured 4 to 6 times/day for 2 to 3 weeks. In addition, both axillary temperature (with a shielded probe) and wrist activity were almost continuously recorded at 15 min intervals during the same time span. Individual time series were analyzed according to several statistical methods (power spectrum, cosinor, chi 2, etc.), in order to estimate the prominent circadian period tau and to evaluate both individual and subgroup differences with regard to tolerance of shift work, age, duration of shift work. The present study confirms for continuously recorded temperature and wrist activity, grip strength of both hands, heart rate and peak expiratory flow that intolerance of shift work is frequently associated with an internal desynchronization. However, this conclusion cannot be extended to circadian rhythms in self-rated drowsiness, fatigue and attention. The internal desynchronization among several circadian rhythms supports the hypothesis that these latter are driven by several oscillators, with presumable differences between right and left hemispheres as suggested by unequal values of tau in rhythms of both hand grip strength. Since an internal desynchronization can be observed in tolerant shift workers having no complaint, it is likely that symptoms of intolerance are related to the subject's sensitivity to internal desynchronization rather than to the desynchronization itself.     

Bacillus thuringiensis protein production, signal transduction, and insect control in chemically inducible PR-1a/cry1Ab broccoli plants

In an effort to develop a chemically inducible system for insect management, we studied production of Cry1Ab Bacillus thuringiensis (Bt) protein and control of the diamondback moth (DBM), Plutella xylostella L., in inducer-treated and untreated tissues of a broccoli line transformed with a PR-1a/cry1Ab expression cassette. Spraying leaves of these plants with the inducer acibenzolar-S-methyl (= 1,2,3 benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester) (ASM) triggered expression of the cry1Ab gene and produced a high level of Cry1Ab protein within 2–3 days. Cry1Ab protein persisted in leaves for at least 8 weeks, providing prolonged protection from P. xylostella attack. Signals generated in inducer-treated leaves were transferred to untreated newly emerged leaves or heads, as seen by production of Cry1Ab protein and/or protection from insect damage in these plant parts. Signal transduction proceeded in an attenuated manner up to the sixth newly emerged leaf. No Cry1Ab protein was detectable by ELISA in uninduced young leaves, but small amounts of the protein were present in uninduced leaves older than 3 weeks and caused some insect mortality. Such basal expression of Bt genes without induction may favor the evolution of resistant insect populations and therefore limits the application of the PR-1a/cry1Ab system for insect management. However, the rapid production and steady maintenance of a high level of transgenic protein upon induction, the signal transduction observed, and the fact that the chemical inducer can be used in field conditions make the PR-1a promoter attractive for chemical regulation of other agriculturally or pharmaceutically important genes for which low expression in the absence of induction is not a concern.     

Role of the autonomic nervous system in generating non-linear dynamics in short-term heart period variability.

We evaluated the role played by the autonomic nervous system in producing non-linear dynamics in short heart period variability (HPV) series recorded in healthy young humans. Non-linear dynamics are detected using an index of predictability based on a local non-linear predictor and a surrogate data approach. Different types of surrogates are utilized: (i) phase-randomized Fourier-transform based (FT) data; (ii) amplitude-adjusted FT (AAFT) data; and (iii) iteratively refined AAFT (IAAFT) data of two types (IAAFT-1 and IAAFT-2). The approach was applied to experimental protocols activating or blocking the sympathetic or parasympathetic branches of the autonomic nervous system or periodically perturbing cardiovascular control via paced respiration at different breathing rates. We found that short-term HPV was mostly linear at rest. Experimental protocols activating the sympathetic or parasympathetic nervous system did not produce non-linear dynamics. In contrast, paced respiration, especially at slow breathing rates, elicited significantly non-linear dynamics. Therefore, in short-term HPV ( approximately 300 beats) the use of non-linear models is not supported by the data, except under conditions whereby the subject is constrained to a slow respiratory rate.