The Effect of Rye Chromosomes on Callus Induction and Regeneration in Callus Cultures of Immature Embryos of Wheat–Rye Substitution Lines,Triticum aestivum L. Cultivar Saratovskaya 29–Secale cereale L. Cultivar Onokhoiskaya

The effect of individual rye chromosomes on the induction of callus and the character of its regenerating capacity was studied with cultured immature embryos of wheat–rye (Triticum aestivum L. cv. Saratovskaya 29–Secale cereale L. cv. Onokhoiskaya) substitution lines. The genotypic diversity of the substitution lines proved to significantly affect variation of parameters characterizing the major types of callus cultures, that is, frequencies of embryogenic calli, which are capable of shoot regeneration, and of morphogenic calli, which produce root structures. Functioning in the genotypic background of common wheat cultivar Saratovskaya 29, chromosomes 2R and 3R of rye cultivar Onokhoiskaya stimulated significantly the induction of embryogenic callus highly capable of shoot regeneration. Rye chromosome 2R present in place of chromosome 2D in the common wheat genome suppressed the induction of callus producing root structures. Rye chromosomes 1R and 6R suppressed the induction of embryogenic callus capable of shoot regeneration.     

Spectrum of CFTR mutations on Réunion Island: impact on neonatal screening

The large heterogeneity in the cystic fibrosis (CF) gene is the main difficulty for genotype characterization. Numerous studies have reported considerable variations in frequencies of CF transmembrane conductance regulator (CFTR) mutations in different populations, such as African, Asian, or European populations. To completely characterize the spectrum of mutations in the CFTR gene in the Réunion Island population, we screened 228 CF chromosomes using denaturing high-pressure liquid chromatography and denaturing gradient gel electrophoresis following by direct sequencing. We identified 27 mutations, accounting for 93% of CF chromosomes. They included three novel mutations (M1T, 3121-3C-->G, and L1324P), which are described in this paper. The detection of such a high proportion of Réunion Island CFTR mutations is important for improving neonatal screening of CF on Réunion Island.     

The Effect of Rye Chromosomes on the Characteristic Features of Androgenesis in Wheat–Rye Substitution Lines Triticum aestivumL. (cv. Saratovskaya 29)/Secale cerealeL. (cv.Onokhoiskaya) and Triticale

The characteristic features of androgenesis in six wheat–rye substitution lines Triticum aestivumL. (cv. Saratovskaya 29)/Secale cerealeL. (cv. Onokhoiskaya) and triticale (2n= 56) using anther culture at different concentrations of 2,4-D in the growth medium were studied. Under variable cultivation conditions, the significant effect of genotypic diversity on the variability of such androgenesis parameters as the frequency of productive anthers, the frequency of embryoid formation, and the frequency of total regenerated plantlets, was shown. It was demonstrated that chromosomes 1R, 3R, and 7R stimulated the formation of androgenous embryoids, while chromosome 5R produced an opposite effect. In triticale and substitution lines, the regeneration ability of androgenous embryoids induced by elevated 2.4-D concentrations was inhibited. Chromosome 1R of the Onokhoiskaya cultivar was suggested to contain genes suppressing regeneration of green plantlets, while chromosome 3R, conversely, stimulated their formation. Chromosomes 1R, 2R, 3R, and 7R of the Onokhoiskaya cultivar did not inhibit the spontaneous formation of androgenous hexaploids in the substitution lines.     

Rye chromosome arm 3RS encodes a homodimeric inhibitor of insect α-amylase

A new inhibitor of insect -amylase, designated RDAI-1, has been purified from rye (Secale cereale L.) endosperm. RDAI-1 is homologous to wheat homodimeric inhibitors. This homology is supported by their similar N-terminal amino-acid sequences, inhibitory activities towards amylases from Tenebrio molitor (Coleoptera) and human saliva, and aggregative properties in gel-filtration chromatography. The gene encoding RDAI-1, IdhaR1, is located on the short arm of chromosome 3R, which is homoeologous with wheat chromosome arms 3BS and 3DS, where the genes for homodimeric inhibitors have been previously mapped.     

Mechanisms of Meiotic Restitution and Their Genetic Regulation in Wheat–Rye Polyhaploids

Meiosis has been studied in partially fertile wheat–rye F₁ hybrids yielded by crosses Triticum aestivum (Saratovskaya 29 variety) × Secale cereale L. (Onokhoiskaya variety) (4x =28). Hybrid self-fertility proved to be caused by formation of restituted nuclei, which appear after equational segregation of univalent chromosome in AI and sister chromatid non-separation in AII of meiosis, as well as after AI blockage in three different ways. Both types of meiotic restitution were found in each hybrid plant. Expression of the meiotic restitution trait varied significantly in polyhaploids of the same genotype (ears of the same plants, anthers of the same ear, microsporocytes of the same anther). Chromatin condensation in prophase proved to be related to the division type and univalent segregation in AI. During reduction segregation of univalents in AI, sister chromatid cohesion and chromosome supercondensation remained unchanged. The results obtained suggest that in the remote hybrids with haploid karyotype of the parental origin (polyhaploids), the program of two-stage meiosis may be fundamentally transformed to ensure one instead of two divisions. We propose that meiotic restitution is a result of special genetic regulation of the kinetochore organization (both structural and functional) and chromatin condensation, i.e. of major meiotic mechanisms.     

Household-Level Expenditure on Protective Measures Against Mosquitoes on the Island of La Réunion,France

Background

For decades La Réunion has experienced a number of epidemics that have resulted in efforts to control the density of Aedes species on this Island. This study was conducted to assess household-level expenditure on protective measures against mosquito nuisance on the Island of La Réunion in 2012.

Methodology/Principal Findings

Data was collected during a cross-sectional survey of 1024 households and used to determine the relationship between the use of chemically-based protective measures and subjective and objective indicators of the density of Aedes albopictus. The average household expenditure in July 2012 was USD 9.86 and the total household-level expenditure over a one-year period was extrapolated to USD 28.05million (range: USD 25.58 million to USD 30.76 million). Much of this money was spent on measures thought to be relatively ineffective against Aedes mosquitoes. Expenditure on protective measures was not influenced by the level of knowledge on mosquitoes or by the visual nuisance they generated at home, but rather by the perception of risk related to a future epidemic of chikungunya and socioeconomic factors. Most importantly, household spending on protective measures was found to be influenced by a measure of zone-level mosquito density (the Breteau index), but not by objective indicators of the presence of mosquitoes within or around the house.

Conclusions/Significance

Household-level expenditure on chemically-based protective measures is high when compared to the investment made by public entities to achieve vector control, and it is differentially influenced by subjective and objective measures of mosquito density. The current situation could be improved, firstly by ensuring that the public is well-informed about mosquitoes and the effectiveness of various protective measures, and secondly by implementing interventions that could either complement current vector-control strategies and improve their effectiveness on a country-level, or that would steer the population toward the appropriate behaviours.     

Spatial pattern of size distribution of four fish species on Réunion coral reef flats

A comparative study of the size distribution of four fish species was performed on three geomorphological zones (back reef, inner reef flat and outer reef flat) on two comparable fringing reef areas (disturbed and non-disturbed) of Reunion Island, S. W. Indian Ocean. The species chosen Chaetodon trifasciatus, Dascyllus aruanus, Stethojulis albovittata and Ctenochaetus striatus were selected both for their abundance and their diverse diets. The method used is based on the estimation of fish size directly underwater by comparison to a graduated table, i.e. photographs of the species for which different size-classes were previously determined. For the two areas, the size of fishes increases from the back reef zone to the outer reef flat, except for D. aruanus which is not present in sufficient numbers on the outer reef flat to allow a statistical analysis. This suggests the existence of a nursery zone in the back reef from which these species might colonize the reef flat. On the back reef zone and the inner reef flat, there is a significant difference in the size distribution of fishes between the disturbed and non-disturbed areas, except for S. albovittata. The number of juveniles is significantly lower in the disturbed area, probably due to environmental perturbations.

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Résumé Une étude de la distribution des tailles de quatre espéces de poissons coralliens a été réalisée sur trois zones géomorphologiques (arriére récif, platier interne et platier externe) de deux secteurs récifaux comparables (dégradé et non dégradé) de l'île de la Réunion, océan Indien occidental. Les espéces étudiées, Chaetodon trisfaciatus, Dascyllus aruanus, Stethojulis albovittata et Ctenochaetus striatus ont été choisies pour leur abondance et leur diversité de régime alimentaire. La technique utilisée consiste á estimer la longueur du poisson directement sous l'eau á l'aide d'une tablette graduée. Des photographies de poissons de différentes tailles, préalablement définies, y ont été fixées, et ceci pour les quatre espéces. Pour les deux secteurs, une augmentation réguliére de la taille des poissons depuis l'arriére récif jusqu' au platier externe est apparue, sauf pour D. Aruanus ui n'est apas suffisamment abondante sur le platier externe pour permettre une analyse statistique. Ces observations suggérent l'existence d'une nurserie dans l'arriére récif á partir duquel pourrait s' opérer la colonisation du platier récifal. Dans les zones d' arriére récif et de platier interne, il y a par ailleurs une différence significative dans la distribution des tailles des poissons entre le secteur dégradé et le secteur non dégradé, sauf pour S. albovittata. Le nombre des juvéniles est significativement plus faible dans le secteur dégradé, ce qui pourrait être dû aux dégradations de l'environment corallien.

     

Multidisciplinary prospective study of mother-to-child chikungunya virus infections on the island of La Réunion

Background

An outbreak of chikungunya virus affected over one-third of the population of La Réunion Island between March 2005 and December 2006. In June 2005, we identified the first case of mother-to-child chikungunya virus transmission at the Groupe Hospitalier Sud-Réunion level-3 maternity department. The goal of this prospective study was to characterize the epidemiological, clinical, biological, and radiological features and outcomes of all the cases of vertically transmitted chikungunya infections recorded at our institution during this outbreak.

Methods and Findings

Over 22 mo, 7,504 women delivered 7,629 viable neonates; 678 (9.0%) of these parturient women were infected (positive RT-PCR or IgM serology) during antepartum, and 61 (0.8%) in pre- or intrapartum. With the exception of three early fetal deaths, vertical transmission was exclusively observed in near-term deliveries (median duration of gestation: 38 wk, range 35–40 wk) in the context of intrapartum viremia (19 cases of vertical transmission out of 39 women with intrapartum viremia, prevalence rate 0.25%, vertical transmission rate 48.7%). Cesarean section had no protective effect on transmission. All infected neonates were asymptomatic at birth, and median onset of neonatal disease was 4 d (range 3–7 d). Pain, prostration, and fever were present in 100% of cases and thrombocytopenia in 89%. Severe illness was observed in ten cases (52.6%) and mainly consisted of encephalopathy (n = 9; 90%). These nine children had pathologic MRI findings (brain swelling, n = 9; cerebral hemorrhages, n = 2), and four evolved towards persistent disabilities.

Conclusions

Mother-to-child chikungunya virus transmission is frequent in the context of intrapartum maternal viremia, and often leads to severe neonatal infection. Chikungunya represents a substantial risk for neonates born to viremic parturients that should be taken into account by clinicians and public health authorities in the event of a chikungunya outbreak.     

Effects of altered FcγR binding on antibody pharmacokinetics in cynomolgus monkeys

Antibody interactions with Fcγ receptors (FcγRs), like FcγRIIIA, play a critical role in mediating antibody effector functions and thereby contribute significantly to the biologic and therapeutic activity of antibodies. Over the past decade, considerable work has been directed towards production of antibodies with altered binding affinity to FcγRs and evaluation of how the alterations modulate their therapeutic activity. This has been achieved by altering glycosylation status at N297 or by engineering modifications in the crystallizable fragment (Fc) region. While the effects of these modifications on biologic activity and efficacy have been examined, few studies have been conducted to understand their effect on antibody pharmacokinetics (PK). We present here a retrospective analysis in which we characterize the PK of three antibody variants with decreased FcγR binding affinity caused by amino acid substitutions in the Fc region (N297A, N297G, and L234A/L235A) and three antibody variants with increased FcγRIIIA binding affinity caused by afucosylation at N297, and compare their PK to corresponding wild type antibody PK in cynomolgus monkeys. For all antibodies, PK was examined at a dose that was known to be in the linear range. Since production of the N297A and N297G variants in Chinese hamster ovary cells results in aglycosylated antibodies that do not bind to FcγRs, we also examined the effect of expression of an aglycosylated antibody, without sequence change(s), in E. coli. All the variants demonstrated similar PK compared with that of the wild type antibodies, suggesting that, for the six antibodies presented here, altered FcγR binding affinity does not affect PK.     

Discovery of stereospecific cytotoxicity of (8R,8′R)-trans-arctigenin against insect cells and structure-activity relationship on aromatic ring

One of the arctigenin stereoisomers, (8R,8′R)-trans-form 1, showed stereospecific cytotoxicity against insect cells, Sf9 and NIAS-AeAl-2 cells. By the comparison with other stereoisomers, the most importance of the 8′R stereochemistry for the higher activities was clarified. On the other hand, the wider range of activity level among stereoisomers against cancer cells, HL-60, was not observed. The structure-activity relationship research using derivatives bearing (8R,8′R)-trans-form was performed to show the same level of activities of 3-iodo, 4-iodo, and 3,4-methylenedioxy derivatives 28, 29, and 36 as (8R,8′R)-trans-arctigenin 1. In the examination of thiono derivatives, 4-iodo thiono and 3,4-methylenedioxy thiono derivatives 66, 67 showed similar level of activities to that of (8R,8′R)-trans-arctigenin 1. The expression of ribosomal 28S rRNA gene of Sf9 cells was increased by (8R,8′R)-trans-arctigenin 1, whereas a degradation of DNA was not observed.     

Rye cytology,cytogenetics and genetics — current status

Summary Progress in rye karyology is reviewed with respect to chromosome structure, recognition and chromosome nomenclature. Considerable contributions have been brought about by molecular techniques which have even revealed nucleotide sequences of some of the ribosomal DNA. DNA sequence organization correlates with the distribution of major Giemsa C-band regions as well as with N-bands and the binding sites of fluorescent dyes. The several banding patterns permit the classification of rye chromosomes. The increased data and widespread application of banding analysis require a consistent system of chromosome and/or band designation. Therefore, a standard band nomenclature is proposed with reference to the recommendations of the Paris Conference on Standardization in Human Cytogenetics. In addition, advances in genetics are summarized and discussed. Based on the original accepted standard karyogram and banding patterns of the rye chromosomes, meanwhile, 120 genes determining several characters have been associated with individual chromosomes and/or chromosome arms, including linkage studies for about 19 arrangements. Most results were obtained using wheat-rye addition lines as well as test crosses with defined translocations. Moreover, genetical studies based on appropriate trisomic and telotrisomic material resulted in the localization of 19 genes, including their linkage relationships.     

Effects of the H6R and D7H Mutations on the Heparin-Dependent Modulation of Zinc-Induced Aggregation of Amyloid β

Molecular Biology - Zinc ions and glycosaminoglycans (GAGs) are found in amyloid deposits and are known to modulate the β-amyloid peptide (Аβ) aggregation, which is thought to be a...     

Mycorrhizal colonizations of ferns and lycophytes on the island of La Réunion in relation to nutrient availability

Very little is known about the degree and ecological correlates of mycorrhization of lycophytes and ferns, although mycorrhizae are believed to be crucial for the majority of land plants. We screened the degree of mycorrhizal colonization for all 75 fern species recorded in nine survey plots across a wide range of soil conditions on the island of La Réunion, including five plots on lava flows of different age. Overall, 66% of all samples had mycorrhizae, but ground-dwelling species had significantly higher colonization levels (78%) than epiphytes (58%). Among ground-dwelling species, 98% of the individuals belonged to species with mycorrhizae, which was significantly higher than at the species level. Most samples had glomeromycetes as fungal partners, but septate endophytes were found in 41% of the colonized samples. While we found no significant relationship between the percentage of fern species with mycorrhizae per plot and seven ecological parameters, the percentage of fern individuals with mycorrhizal colonizations per plot significantly increased on shallow soils with high pH values and high base-saturation. This supports the idea that mycorrhizal colonizations confer an ecological advantage to colonized individuals, and that this advantage is more pronounced on nutrient-deficient sites. Our study thus provides evidence for an ecological advantage of mycorrhizae for ferns, but raises the question why, despite this advantage, species level mycorrhization among ferns (68%) is so much lower than the average for land plants (85%).     

Biallelic Mutations of Methionyl-tRNA Synthetase Cause a Specific Type of Pulmonary Alveolar Proteinosis Prevalent on Réunion Island

Methionyl-tRNA synthetase (MARS) catalyzes the ligation of methionine to tRNA and is critical for protein biosynthesis. We identified biallelic missense mutations in MARS in a specific form of pediatric pulmonary alveolar proteinosis (PAP), a severe lung disorder that is prevalent on the island of Réunion and the molecular basis of which is unresolved. Mutations were found in 26 individuals from Réunion and nearby islands and in two families from other countries. Functional consequences of the mutated alleles were assessed by growth of wild-type and mutant strains and methionine-incorporation assays in yeast. Enzyme activity was attenuated in a liquid medium without methionine but could be restored by methionine supplementation. In summary, identification of a founder mutation in MARS led to the molecular definition of a specific type of PAP and will enable carrier screening in the affected community and possibly open new treatment opportunities.     

Effect of Infection with Ribonucleic Acid Bacteriophage R23 on the Inducible Synthesis of β-Galactosidase in Escherichia coli

Infection by ribonucleic acid (RNA) bacteriophage R23 inhibited the synthesis of beta-galactosidase in Escherichia coli. The inhibition, although not complete, was apparent shortly after infection and was maximal after the first 20 min of infection. R23 diminished the beta-galactosidase-synthesizing capacity when inducer was added after phage infection, but not when infection followed inducer removal. These findings suggested that the primary effect of R23 on enzyme-forming capacity was limitation of synthesis of enzyme-specific messenger RNA. Studies with ultraviolet irradiated phage and amber mutants of R23 indicated that the inhibitory process could be separated into two phases. Early inhibition did not require the expression of the viral genome, whereas late inhibition required the expression of the viral RNA synthetase cistron.     

Effect of the Disease-Causing R266K Mutation on the Heme and PLP Environments of Human Cystathionine β-Synthase

Cystathionine β-synthase (CBS) is an essential pyridoxal 5'-phosphate (PLP)-dependent enzyme of the transsulfuration pathway that condenses serine with homocysteine to form cystathionine; intriguingly, human CBS also contains a heme b cofactor of unknown function. Herein we describe the enzymatic and spectroscopic properties of a disease-associated R266K hCBS variant, which has an altered hydrogen-bonding environment. The R266K hCBS contains a low-spin, six-coordinate Fe(III) heme bearing a His/Cys ligation motif, like that of WT hCBS; however, there is a geometric distortion that exists at the R266K heme. Using rR spectroscopy, we show that the Fe(III)-Cys(thiolate) bond is longer and weaker in R266K, as evidenced by an 8 cm(-1) downshift in the ν(Fe-S) resonance. Presence of this longer and weaker Fe(III)-Cys(thiolate) bond is correlated with alteration of the fluorescence spectrum of the active PLP ketoenamine tautomer. Activity data demonstrate that, relative to WT, the R266K variant is more impaired in the alternative cysteine-synthesis reaction than in the canonical cystathionine-synthesis reaction. This diminished cysteine synthesis activity and a greater sensitivity to exogenous PLP correlate with the change in PLP environment. Fe-S(Cys) bond weakening causes a nearly 300-fold increase in the rate of ligand switching upon reduction of the R266K heme. Combined, these data demonstrate cross talk between the heme and PLP active sites, consistent with previous proposals, revealing that alteration of the Arg(266)-Cys(52) interaction affects PLP-dependent activity and dramatically destabilizes the ferrous thiolate-ligated heme complex, underscoring the importance of this hydrogen-bonding residue pair.     

Molecular Cloning and Expression of an α-Amylase Inhibitor from Rye with Potential for Controlling Insect Pests

Alpha-amylase inhibitors have important roles in plant defense mechanisms, particularly against insects, and several of these inhibitors have been expressed in different crops to increase their resistance to particular insects. In this work, we report the cloning and expression of a gene encoding for a new -amylase inhibitor (BIII) from rye (Secale cereale) seeds. The BIII gene contains 354 nucleotides that encode for 118 amino acids sequence. A 313 bp fragment of the gene was expressed in Escherichia coli and resulted in a functional inhibitor that reduced the activity of -amylases of larvae of the coleopteran pests Acanthoscelides obtectus, Zabrotess subfasciatus and Anthonomus grandis. In contrast, the inhibitor did not inhibit the activity of porcine pancreatic -amylase. Although the amino acid sequence of BIII showed high identity with those of bifunctional inhibitors, the recombinant protein was unable to inhibit trypsin-like serine proteinases. The effects of recombinant BIII were evaluated in vivo against A. grandis. When first instar larvae were reared on an artificial diet containing four different concentrations of BIII, a reduction in larval weight and a mortality of 83% were observed at the highest concentration.     

Spontaneous and Divergent Hexaploid Triticales Derived from Common Wheat × Rye by Complete Elimination of D-Genome Chromosomes

Background

Hexaploid triticale could be either synthesized by crossing tetraploid wheat with rye, or developed by crossing hexaploid wheat with a hexaploid triticale or an octoploid triticale.

Methodology/Principal Findings

Here two hexaploid triticales with great morphologic divergence derived from common wheat cultivar M8003 (Triticum aestivum L.) × Austrian rye (Secale cereale L.) were reported, exhibiting high resistance for powdery mildew and stripe rust and potential for wheat improvement. Sequential fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) karyotyping revealed that D-genome chromosomes were completely eliminated and the whole A-genome, B-genome and R-genome chromosomes were retained in both lines. Furthermore, plentiful alterations of wheat chromosomes including 5A and 7B were detected in both triticales and additionally altered 5B, 7A chromosome and restructured chromosome 2A was assayed in N9116H and N9116M, respectively, even after selfing for several decades. Besides, meiotic asynchrony was displayed and a variety of storage protein variations were assayed, especially in the HMW/LMW-GS region and secalins region in both triticales.

Conclusion

This study confirms that whole D-genome chromosomes could be preferentially eliminated in the hybrid of common wheat × rye, “genome shock” was accompanying the allopolyploidization of nascent triticales, and great morphologic divergence might result from the genetic variations. Moreover, new hexaploid triticale lines contributing potential resistance resources for wheat improvement were produced.     

A Mathematical Model of Chikungunya Dynamics and Control: The Major Epidemic on Réunion Island

Chikungunya is a re-emerging arboviral disease transmitted by Aedes spp. mosquitoes. Although principally endemic to Africa and Asia, recent outbreaks have occurred in Europe following introductions by returning travellers. A particularly large outbreak occurred on Réunion Island in 2006, the published data from which forms the basis of the current study. A simple, deterministic mathematical model of the transmission of the virus between humans and mosquitoes was constructed and parameterised with the up-to-date literature on infection biology. The model is fitted to the large Réunion epidemic, resulting in an estimate of 4.1 for the type reproduction number of chikungunya. Although simplistic, the model provided a close approximation of both the peak incidence of the outbreak and the final epidemic size. Sensitivity analysis using Monte Carlo simulation demonstrated the strong influence that both the latent period of infection in humans and the pre-patent period have on these two epidemiological outcomes. We show why separating these variables, which are epidemiologically distinct in chikungunya infections, is not only necessary for accurate model fitting but also important in informing control.