Effect of Far Red Light on Drought Resistance of Cotton

The resistance of cotton (Gossypium hirsutum L.) to droughtstress was increased when plants, grown under a 9 h light period,received a 30 min far red (FR) illumination at the beginningof the dark period. With the addition of FR light, the plantsdisplayed higher stomatal resistance and lower rate of transpiration.Therefore, with the addition of FR, the plants remained at higherleaf turgor potential during the period of drought stress whencompared to plants stressed without the FR illumination. ThusFR illumination improved the water economy of the plants. (Received April 20, 1982; Accepted August 30, 1982)     

Importance of temperature and seed water content on the induction of imaginal polymorphism in Callosobruchus maculatus

Callosobruchus maculatus (F.) is a tropical insect (Coleoptera: Bruchidae) that develops in Vigna unguiculata (Walp) seeds. In this beetle, there are two distinct adult forms that differ in their morphology, physiology and behaviour, the flight form and the flightless form. The development of C. maculatus is analyzed in a traditional store in Niger. During the dry season, 6 to 7 generations of the flightless form develop in the store. When the atmospheric water content increases during the rainy season, adults of the flight form appear and escape from the store. Experimental studies have shown that the adult polymorphism is induced during post-embryonic development and depends on prevailing abiotic factors during this period. The proportion of flight from adults is high when larvae develop in moist seeds (14–15% of water content). Under dry conditions (6–7% of water content) only flightless adult forms emerge from the seeds. Temperatures during development also influence adult polymorphism. In thermoperiodic conditions with 12–13% seed water content, the proportion of flight from adults increases with increasing duration of the thermophase. However, at low temperatures, a high proportion of flightless adult forms emerge, regardless of seed water content. The adaptive importance of these two abiotic factors on polymorphism induction is examined in this study.

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Résumé Callosobruchus maculatus (F.) est un Coléoptère Bruchidae tropical qui se développe aux dépens des graines de Vigna unguiculata. Les adultes présentent un polymorphisme; il y a en effet deux formes, la forme voilière et la forme non voilière, distinctes par des critères morphologiques, physiologiques et comportementaux. L'évolution des populations de C. maculatus a été suivie pendant toute la saison sèche et le début de la saison des pluies dans la région de Niamey au Niger (13° LN) à l'intérieur d'un grenier traditionnel. Pendant toute la saison sèche, 6 à 7 générations de C. maculatus de la forme non voilière se succèdent à l'intérieur du grenier. Les adultes de la forme voilière, très actifs, apparaissent surtout au cours de la saison des pluies lorsque la teneur en eau de l'atmosphère et la teneur en eau des graines augmentent. Les études expérimentales réalisées au laboratoire montrent que le polymorphisme imaginal est induit au cours du développement post-embryonnaire et dépend des conditions climatiques dans lesquelles celui-ci a lieu. Le taux d'adultes de la forme voilière est élevé lorsque les larves se développent dans des graines à forte teneur en eau (14 ou 15%). Lorsque la teneur en eau des graines est faible (6 à 7%), il n'y a émergence que d'adultes de la forme non voilière. Lorsque la teneur en eau des graines est comprise entre 12 et 13%, le taux d'adultes de la forme voilière s'accroit et varie avec la durée de la thermophase. A basse température il y a toujours émergence d'adultes de la forme non voilière, quelle que soit la teneur en eau des graines. L'influence de ces deux facteurs abiotiques sur l'induction du polymorphisme imaginal joue probablement un rôle important dans les mécanismes adaptatifs permettant le maintien de cette espèce en zone tropicale.

     

Biological Status and Dietary Intakes of Iron,Zinc and Vitamin A among Women and Preschool Children in Rural Burkina Faso

Background

Food-based approaches such as biofortification are meant to sustainably address micronutrient deficiencies in poor settings. Knowing more about micronutrient intakes and deficiencies is a prerequisite to designing and evaluating interventions.

Objective

The objectives of the study were to assess biological status and dietary intakes of iron, zinc and vitamin A among women and children aged 36–59 months in rural Burkina Faso and to study relationships between intake and status to better inform future food-based interventions.

Design

A cross-sectional survey was carried out in two rural provinces of Burkina Faso on a random cluster sample of 480 mother-child pairs. Dietary data was obtained by 24-hour recalls repeated on a random sub-selection of 37.5% of subjects to allow calculation of nutrient’s probability of adequacy (PA). Biomarkers were measured on a sub-sample of 180 mother-child pairs. Blood samples were analyzed for hemoglobin, serum ferritin, soluble transferrin receptors (sTfR), C-reactive protein, alpha-1-glycoprotein, serum zinc concentration (SZnC) and retinol. For each micronutrient the relationship between biomarker and dietary intake was investigated by multiple linear regression models accounting for inflammatory biomarkers.

Results

Mean PA for iron, zinc and vitamin A was 0.49, 0.87 and 0.21 among women and 0.61, 0.95 and 0.33 among children, respectively. Prevalence of anemia, corrected low serum ferritin and high sTfR was 37.6%, 4.0% and 77.5% among women and 72.1%, 1.5% and 87.6% among children, respectively. Prevalence of low SZnC and corrected low serum retinol was 39.4% and 12.0% among women and 63.7% and 24.8% among children, respectively. There was a tendency for a positive relationship between vitamin A intakes and serum retinol among women (β = 0.0003, P = 0.06). Otherwise, no link was found between micronutrients biomarkers and intakes.

Conclusion

Our study depicted different images of micronutrient deficiencies when based on dietary intakes or biomarkers results, thus highlighting the need for more suitable biomarkers and more precise measures of absorbable micronutrient intakes at the individual level. It thus points to challenges in the design and evaluation of future biofortification or other food-based interventions in rural areas of Burkina Faso.     

2-alkyl-3-Alkylamino-2H-Benzo- and pyridothiadiazine 1,1-dioxides: from K+ATP channel openers to Ca++ channel blockers?

A series of 2-alkyl-3-alkylamino-2H-benzo- and 2-alkyl-3-alkylamino-2H-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxides, structurally related to BPDZ 44 and BPDZ 73, two potent pancreatic B-cells K+ATP channel openers, were synthesized and tested on rat pancreatic islets (endocrine tissue) as well as on rat aorta rings (vascular smooth muscle tissue). Alkylation of the 2-position led to double bond tautomerization and formation of compounds with a 2H-conformation. In contrast to the previously described pyridothiadiazine dioxides, such as BPDZ 44, and 7-chlorobenzothiadiazine dioxides, such as BPDZ 73, the 2-alkyl-substituted analogs were found to be poorly active on the insulin releasing process although most drugs exhibited a vasorelaxant activity. As a result, the new 2-alkyl-substituted pyridinic compounds expressed a selectivity profile (vascular smooth muscle tissue vs pancreatic tissue) opposite to that of their non-alkyl-substituted counterparts, i.e. BPDZ 44. Additional investigations revealed that, in contrast to their non 2-alkyl-substituted analogs, the most interesting 2-methyl-substituted derivatives did not express the pharmacological profile of classical K+ATP channel openers. The pharmacological results rather suggest that alkylation of the 2-position of the thiadiazine ring led to drugs that could act as Ca2+ channel blockers rather than as potassium channel openers.     

Prevalence of the dhfr and dhps Mutations among Pregnant Women in Rural Burkina Faso Five Years after the Introduction of Intermittent Preventive Treatment with Sulfadoxine-Pyrimethamine

Background

The emergence and spread of drug resistance represents one of the biggest challenges for malaria control in endemic regions. Sulfadoxine-pyrimethamine (SP) is currently deployed as intermittent preventive treatment in pregnancy (IPTp) to prevent the adverse effects of malaria on the mother and her offspring. Nevertheless, its efficacy is threatened by SP resistance which can be estimated by the prevalence of dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr) mutations. This was measured among pregnant women in the health district of Nanoro, Burkina Faso.

Methods

From June to December 2010, two hundred and fifty six pregnant women in the second and third trimester, attending antenatal care with microscopically confirmed malaria infection were invited to participate, regardless of malaria symptoms. A blood sample was collected on filter paper and analyzed by PCR-RFLP for the alleles 51, 59, 108, 164 in the pfdhfr gene and 437, 540 in the pfdhps gene.

Results

The genes were successfully genotyped in all but one sample (99.6%; 255/256) for dhfr and in 90.2% (231/256) for dhps. The dhfr C59R and S108N mutations were the most common, with a prevalence of 61.2% (156/255) and 55.7% (142/255), respectively; 12.2% (31/255) samples had also the dhfr N51I mutation while the I164L mutation was absent. The dhps A437G mutation was found in 34.2% (79/231) isolates, but none of them carried the codon K540E. The prevalence of the dhfr double mutations NRNI and the triple mutations IRNI was 35.7% (91/255) and 11.4% (29/255), respectively.

Conclusion

Though the mutations in the pfdhfr and pfdhps genes were relatively common, the prevalence of the triple pfdhfr mutation was very low, indicating that SP as IPTp is still efficacious in Burkina Faso.     

Molecular dynamics simulation approach for the prediction of transmembrane helix–helix heterodimers assembly

Computational methods are useful to identify favorable structures of transmembrane (TM) helix oligomers when experimental data are not available or when they cannot help to interpret helix-helix association. We report here a global search method using molecular dynamics (MD) simulations to predict the structures of transmembrane homo and heterodimers. The present approach is based only on sequence information without any experimental data and is first applied to glycophorin A to validate the protocol and to the HER2-HER3 heterodimer receptor. The method successfully reproduces the experimental structures of the TM domain of glycophorin A (GpA(TM)) with a root mean square deviation of 1.5 A. The search protocol identifies three energetically stable models of the TM domain of HER2-HER3 receptor with favorable helix-helix arrangement, including right-handed and left-handed coiled-coils. The predicted TM structures exhibit the GxxxG-like motif at the dimer interface which is presumed to drive receptor oligomerization. We demonstrate that native structures of TM domain can be predicted without quantitative experimental data. This search protocol could help to predict structures of the TM domain of HER heterodimer family.     

Emergence of epidemic Neisseria meningitidis serogroup X meningitis in Togo and Burkina Faso

Serogroup X meningococci (NmX) historically have caused sporadic and clustered meningitis cases in sub-Saharan Africa. To study recent NmX epidemiology, we analyzed data from population-based, sentinel and passive surveillance, and outbreak investigations of bacterial meningitis in Togo and Burkina Faso during 2006-2010. Cerebrospinal fluid specimens were analyzed by PCR. In Togo during 2006-2009, NmX accounted for 16% of the 702 confirmed bacterial meningitis cases. Kozah district experienced an NmX outbreak in March 2007 with an NmX seasonal cumulative incidence of 33/100,000. In Burkina Faso during 2007-2010, NmX accounted for 7% of the 778 confirmed bacterial meningitis cases, with an increase from 2009 to 2010 (4% to 35% of all confirmed cases, respectively). In 2010, NmX epidemics occurred in northern and central regions of Burkina Faso; the highest district cumulative incidence of NmX was estimated as 130/100,000 during March-April. Although limited to a few districts, we have documented NmX meningitis epidemics occurring with a seasonal incidence previously only reported in the meningitis belt for NmW135 and NmA, which argues for development of an NmX vaccine.     

Genetic diversity and population structure of the secondary symbiont of tsetse flies, Sodalis glossinidius, in sleeping sickness foci in Cameroon

Background

Previous studies have shown substantial differences in Sodalis glossinidius and trypanosome infection rates between Glossina palpalis palpalis populations from two Cameroonian foci of human African trypanosomiasis (HAT), Bipindi and Campo. We hypothesized that the geographical isolation of the two foci may have induced independent evolution in the two areas, resulting in the diversification of symbiont genotypes.

Methodology/Principal Findings

To test this hypothesis, we investigated the symbiont genetic structure using the allelic size variation at four specific microsatellite loci. Classical analysis of molecular variance (AMOVA) and differentiation statistics revealed that most of the genetic diversity was observed among individuals within populations and frequent haplotypes were shared between populations. The structure of genetic diversity varied at different geographical scales, with almost no differentiation within the Campo HAT focus and a low but significant differentiation between the Campo and Bipindi HAT foci.

Conclusions/Significance

The data provided new information on the genetic diversity of the secondary symbiont population revealing mild structuring. Possible interactions between S. glossinidius subpopulations and Glossina species that could favor tsetse fly infections by a given trypanosome species should be further investigated.     

The Duplicated Genes Database: Identification and Functional Annotation of Co-Localised Duplicated Genes across Genomes

Background

There has been a surge in studies linking genome structure and gene expression, with special focus on duplicated genes. Although initially duplicated from the same sequence, duplicated genes can diverge strongly over evolution and take on different functions or regulated expression. However, information on the function and expression of duplicated genes remains sparse. Identifying groups of duplicated genes in different genomes and characterizing their expression and function would therefore be of great interest to the research community. The ‘Duplicated Genes Database’ (DGD) was developed for this purpose.

Methodology

Nine species were included in the DGD. For each species, BLAST analyses were conducted on peptide sequences corresponding to the genes mapped on a same chromosome. Groups of duplicated genes were defined based on these pairwise BLAST comparisons and the genomic location of the genes. For each group, Pearson correlations between gene expression data and semantic similarities between functional GO annotations were also computed when the relevant information was available.

Conclusions

The Duplicated Gene Database provides a list of co-localised and duplicated genes for several species with the available gene co-expression level and semantic similarity value of functional annotation. Adding these data to the groups of duplicated genes provides biological information that can prove useful to gene expression analyses. The Duplicated Gene Database can be freely accessed through the DGD website at http://dgd.genouest.org.