Nerve growth factor β polypeptide (NGFB) genetic variability: association with the methadone dose required for effective maintenance treatment

Opioid addiction is a chronic disease with high genetic contribution and a large inter-individual variability in therapeutic response. The goal of this study was to identify pharmacodynamic factors that modulate methadone dose requirement. The neurotrophin family is involved in neural plasticity, learning, memory and behavior and deregulated neural plasticity may underlie the pathophysiology of drug addiction. Brain-derived neurotrophic factor (BDNF) was shown to affect the response to methadone maintenance treatment. This study explores the effects of polymorphisms in the nerve growth factor (β polypeptide) gene, NGFB, on the methadone doses required for successful maintenance treatment for heroin addiction. Genotypes of 14 NGFB polymorphisms were analyzed for association with the stabilizing methadone dose in 72 former severe heroin addicts with no major co-medications. There was significant difference in methadone doses required by subjects with different genotypes of the NGFB intronic single-nucleotide polymorphism rs2239622 (P=0.0002). These results may have clinical importance.

Association of polymorphisms of the cannabinoid receptor (CNR1) and fatty acid amide hydrolase (FAAH) genes with heroin addiction: impact of long repeats of CNR1

Alterations in expression of a cannabinoid receptor (CNR1, CB1), and of fatty acid amide hydrolase (FAAH) that degrades endogenous ligands of CB1, may contribute to the development of addiction. The 385C>A in the FAAH gene and six polymorphisms of CNR1 were genotyped in former heroin addicts and control subjects (247 Caucasians, 161 Hispanics, 179 African Americans and 19 Asians). In Caucasians, long repeats (>or=14) of 18087-18131(TAA)(8-17) were associated with heroin addiction (P=0.0102). Across three ethnicities combined, a highly significant association of long repeats with heroin addiction was found (z=3.322, P=0.0009). Point-wise significant associations of allele 1359A (P=0.006) and genotype 1359AA (P=0.034) with protection from heroin addiction were found in Caucasians. Also in Caucasians, the genotype pattern, 1359G>A and -6274A>T, was significantly associated with heroin addiction experiment wise (P=0.0244). No association of FAAH 385C>A with heroin addiction was found in any group studied.

Physical mapping of rDNA and heterochromatin in chromosomes of 16 Coffea species: a revised view of species differentiation

The chromosome organization among 15 wild diploid Coffea species and cultivated tetraploid C. arabica was determined by fluorochrome banding (CMA, DAPI) and double fluorescence in-situ hybridization (FISH) of 5S and 18S rDNA achieved on the same chromosome plates. Two to five chromosome pairs (plus one putative chromosome B) are marked. Overall, there are two SAT-chromosome pairs for East African species and one for the Malagasy and the West and Central African species. 18S rDNA loci are telomeric and strongly marked the SAT-chromosome pairs. Generally, only one pericentromeric 5S rDNA locus characterized East African species, while an additional minor locus co-localized with the 18S rDNA-SAT locus for the Malagasy species and West and Central African species. A combination of rDNA FISH plus CMA and DAPI banding patterns enables identification of almost all the species, even those for which the genetic or botanical status is still being discussed. C. arabica clearly appears to be an allotetraploid species, including one genome from East Africa and one from West and Central Africa. However, since the minor 5S rDNA-SAT locus present in West/Central African genomes is not detected, two evolutionary hypotheses could be put forward for C. arabica. Considering only the diploid species, global trends are obvious in rDNA signal patterns, genome size variations, and geographic distribution of the species, but there are no clear evolutionary trends. However, complex interactions between these factors and environmental growing conditions exist, which have resulted in loss and gain of rDNA loci and probably also in copy repeat number variations in each rDNA family.

MHC fine mapping of human type 1 diabetes using the T1DGC data

AIM

The human Major Histocompatibility Complex (MHC) is a highly polymorphic genomic region occupying approximately 4 Mb on chromosome 6p21.3. The relationship between human MHC and type 1 diabetes (T1D) has been previously investigated. To fine map the disease locus in this region, we carried out both linkage and association analyses using the Type 1 Diabetes Genetics Consortium data.

METHODS

Two-point linkage analysis was performed with a set of microsatellite markers assuming a fully recessive inheritance model, where we found clustering of high LOD (logarithm of the odds) scores across the MHC region. To narrow down the linkage region, we performed association analyses using both microsatellite and two sets of single nucleotide polymorphism (SNP) markers. We focused on the nuclear families containing a discordant sib-pair (an affected and unaffected sib). For the microsatellite markers, we computed the average repeat length for each individual and carried out a paired t-test.

RESULTS

Microsatellite marker D6S2884 showed the highest association in a sharp peak with a p value of 3.15E-24. We confirmed this finding when using also SNP markers performing a McNemar's test for association. The SNPs that showed the most significant evidence of association mapped to almost the same location as the microsatellite markers.

CONCLUSIONS

Besides the main goal of fine mapping of T1D genes, our results also illustrated the differences and the advantage of using both linkage and association analyses. After the identification of a wide peak with linkage analysis, we were able to dramatically narrow down the region by performing association analysis.

Experimental and modeling study of the ion-molecule association reaction H3O++H2O(+M)→H5O2+(+M)

Experimental results for the rate of the association reaction H3O+ + H2O (+M) --> H5O2(+) (+M) obtained with the Cinetique de Reactions en Ecoulement Supersonique Uniforme flow technique are reported. The reaction was studied in the bath gases M=He and N2, over the temperature range of 23-170 K, and at pressures between 0.16 and 3.1 mbar. At the highest temperatures, the reaction was found to be close to the limiting low-pressure termolecular range, whereas the limiting high-pressure bimolecular range was approached at the lowest temperatures. Whereas the low-pressure rate coefficients can satisfactorily be reproduced by standard unimolecular rate theory, the derived high-pressure rate coefficients in the bath gas He at the lowest temperatures are found to be markedly smaller than given by simple ion-dipole capture theory. This result differs from previous observations on the related reaction NH4(+) + NH3 (+M) --> N2H7(+) (+M). This observation is tentatively attributed to more pronounced contributions of the valence part of the potential-energy surface to the reaction in H5O2(+) than in N2H7(+). Falloff curves of the reaction H3O+ + H2O (+M) --> H5O2(+) (+M) are constructed over wide ranges of conditions and represented in compact analytical form.

SSR cross-amplification and variation within coffee trees (Coffea spp.)

Primer sets were developed from 85 Coffea arabica sequences in addition to 25 already published primer sets. They were subsequently used for amplification in six African Coffea species: Coffea canephora (CAN), Coffea eugenioides (EUG), Coffea heterocalyx (HET), Coffea liberica (LIB), Coffea sp. Moloundou (MOL) and Coffea pseudozanguebariae (PSE). The amplification percentages for these 110 primer pairs ranged from 72.7% for LIB to 86.4% for PSE. Good transferability was thus obtained within the Coffea genus. When focusing on the two species CAN and PSE, high genetic diversity, high polymorphic locus rates (above 80%) and a mean allele number per polymorphic locus of more than 3 were noted. The estimated null allele percentage was -11% for PSE and -9% for CAN. Sixty three percent (CAN) and 79.5% (PSE) of the fixation index (Fis) values were positive. The within-species polymorphism information content (PIC) distribution showed two modes for both species. Although the two species shared 30 polymorphic loci, no correlation between CAN and PSE PIC values was obtained. All of these data are discussed in relation to the polymorphism level and the potential use of these SSRs for subsequent analysis of genetic diversity or genetic mapping.

Base Composition of Coffea AFLP Sequences and Their Conservation Within the Genus

Amplified fragment length polymorphism (AFLP) is often used for genetic mapping and diversity analysis, but very little information is currently available on their sequence characteristics. Species-specific sequences were analyzed from a single Coffea genome (Coffea pseudozanguebariae) associated with clustered or nonclustered AFLP loci of known genetic position. Compared with the expressed sequence tag (EST) sequence composition, their AT content exhibited a bimodal distribution with AT-poor sequences corresponding mainly to putative coding sequences. AT-rich sequences, apart from the EST distribution, were usually clustered on the genetic map and might correspond to noncoding sequences. Conversion of these AFLP markers into sequence-characterized amplified region (SCAR) anchor markers allowed us to assess sequence conservation within Coffea species with respect to species relatedness.

Genome size variations in diploid African Coffea species

Flow cytometry was conducted to evaluate genome size diversity among African diploid species of the Coffea genus. The study included 15 species and six new taxa from Congolese and Cameroonian forest regions which have yet to be botanically characterized. Between-population differences were also recorded in some cases. These evaluations using an internal standard were highly correlated with previous results obtained with an external standard, but differences of up to 18 % existed for some species, involving stoichiometric errors. Consequently, genome size variation between species and within species are discussed as true genome size differences or stoichiometric errors. Environmental and phenotypic correlations with genome size are also discussed.

Gene flow estimation with microsatellites in a Malagasy seed orchard of Eucalyptus grandis

Eucalyptus grandis has a mixed-mating reproductive system. Malagasy Eucalyptus seed orchards were established 15 years ago with two aims both based on panmixia: open-pollinated seed production and genetic improvement. The panmixia hypothesis has never been confirmed in the seed orchard. From a seedling seed-orchard stand comprising 349 trees and using data obtained with six selected microsatellite markers, paternity analysis was performed for 724 offspring collected on 30 adult trees. Paternity assignment, based on exclusion procedures and likelihood-ratio method, was achieved with high accuracy; the exclusion probability value was 0.997. The outcrossing rate was very high (96.7%). More than 50% of potential male trees (199 out of 349) in the seed orchard contributed to pollination for 440 offspring of 30 progenies (8.6% of the basic population). The pollination rate from outside the seed orchard was high (39.2%), but might be due to the small size of this seed orchard. This study showed that "panmixia-like pollination" can be assumed.

Genetic mapping of a caffeoyl-coenzyme A 3-O-methyltransferase gene in coffee trees. Impact on chlorogenic acid content

Chlorogenic acids (CGA) are involved in the bitterness of coffee due to their decomposition in phenolic compounds during roasting. CGA mainly include caffeoyl-quinic acids (CQA), dicaffeoyl-quinic acids (diCQA) and feruloyl-quinic acids (FQA), while CQA and diCQA constitute CGA sensu stricto (CGA s.s.). In the two cultivated species Coffea canephora and Coffea arabica, CGA s.s. represents 88% and 95% of total CGA, respectively. Among all enzymes involved in CGA biosynthesis, caffeoyl-coenzyme A 3-O-methyltransferase (CCoAOMT) is not directly involved in the CGA s.s. pathway, but rather in an upstream branch leading to FQA through feruloyl-CoA. We describe how a partial cDNA corresponding to a CCoAOMT encoding gene was obtained and sequenced. Specific primers were designed and used for studying polymorphism and locating the corresponding gene on a genetic map obtained from an interspecific backcross between Coffea liberica var. Dewevrei and Coffea pseudozanguebariae. Offspring of this backcross were also evaluated for the chlorogenic acid content in their green beans. A 10% decrease was observed in backcross progenies that possess one C. pseudozanguebariae allele of the CCoAOMT gene. This suggests that CGA s.s. accumulation is dependent on the CCoAMT allele present and consequently on the activity of the encoded isoform, whereby CGA accumulation increases as the isoform activity decreases. Possible implications in coffee breeding are discussed.

Effects of caffeine and chlorogenic acid on propidium iodide accessibility to DNA: consequences on genome size evaluation in coffee tree

Estimates of genome size using flow cytometry can be biased by the presence of cytosolic compounds, leading to pseudo-intraspecific variation in genome size. Two important compounds present in coffee trees-caffeine and chlorogenic acid-modify accessibility of the dye propidium iodide to Petunia DNA, a species used as internal standard in our genome size evaluation. These compounds could be responsible for intraspecific variation in genome size since their contents vary between trees. They could also be implicated in environmental variations in genome size, such as those revealed when comparing the results of evaluations carried out on different dates on several genotypes.

Identification and mapping of a major gene (Ft1) involved in fructification time in the interspecific cross Coffea pseudozanguebariae x C. liberica var. Dewevrei: impact on caffeine content and seed weight

Fructification time was studied in the interspecific cross Coffea pseudozanguebariae x C. liberica var. Dewevrei (PSE x DEW). Parental species, F(1) hybrids and offspring of the first backcross generation (BC(1)), consisting of F(1) x PSE (BCPSE) and F(1) x DEW (BCDEW) plants, were observed. Fructification time can be split into two independent visual phases: the full-growth period, from blooming up to the end of fruit growth, and the maturation phase, defined by the green to red color change. Fructification time was found to be an additive trait. The full-growth period showed a bimodal distribution in the BCDEW hybrid, suggesting the involvement of Ft1, a major gene that was mapped on linkage group E. The main effects of Ft1 were to lower caffeine content and 100-seed weight, without any impact on chlorogenic acid, trigonelline and sucrose contents. Two molecular markers were identified that bracket Ft1 and which could be used for early marker-assisted selection.

Pollen viability restoration in a Coffea canephora P. and C. heterocalyx Stoffelen backcross. QTL identification for marker-assisted selection

Male fertility of interspecific hybrids was analysed in one F1 and two backcrossed progenies originating from a cross between Coffea canephora and Coffea heterocalyx. Male fertility was tested using pollen stainability with acetic carmine. The results showed a marked decline in fertility at the F1 level, and fertility was almost fully restored after two backcrosses. The computed broad-sense heritability represented 47% of the variance. Quantitative trait loci (QTLs) locations and effects on pollen viability were estimated using an amplified fragment length polymorphism (AFLP) genetic linkage map constructed in the segregating BC1 population. Three significant QTLs (LOD>3 and p < 0.001 by ANOVA) were detected for pollen viability, two of which were responsible for the bimodal distribution of pollen viability in the segregating population. One QTL was involved in fertility variations among fertile BC1 plants. Fertility inheritance is discussed in relation with previously demonstrated chromosomal sterility in Coffea hybrids and the effect of detected QTLs. The potential use of genetic markers to overcome sterility in interspecific hybrids is also discussed.

Introgression of self-compatibility from Coffea heterocalyx to the cultivated species Coffea canephora

Self-compatibility segregation was assessed in two successive backcross progenies originating from an interspecific cross between Coffea canephora (self-incompatible) and Coffea heterocalyx (self-compatible). After self- and cross-pollination, pollen tube behaviour in styles was observed under ultraviolet fluorescence microscopy and fruit-set was determined at harvesting time. Segregation ratios in the two progenies were consistent with monofactorial control of self-compatibility. Self-compatible plants exhibited higher fruit-set than self-incompatible ones in open-pollination conditions. Segregation of AFLP markers was scored in the first backcross progeny. By molecular linkage analysis, the S locus could be mapped to a short linkage group.

Various levels of cross-resistance to Bacillus sphaericus strains in Culex pipiens (Diptera: Culicidae) colonies resistant to B. sphaericus strain 2362

We studied the cross-resistance to three highly toxic Bacillus sphaericus strains, IAB-59 (serotype H6), IAB-881 (serotype H3), and IAB-872 (serotype H48), of four colonies of the Culex pipiens complex resistant to B. sphaericus 2362 and 1593, both of which are serotype H5a5b strains. Two field-selected highly resistant colonies originating from India (KOCHI, 17,000-fold resistance) and France (SPHAE, 23,000-fold resistance) and a highly resistant laboratory-selected colony from California (GeoR, 36,000-fold resistance) showed strong cross-resistance to strains IAB-881 and IAB-872 but significantly weaker cross-resistance to IAB-59 (3- to 43-fold resistance). In contrast, a laboratory-selected California colony with low-level resistance (JRMM-R, 5-fold resistance) displayed similar levels of resistance (5- to 10-fold) to all of the B. sphaericus strains tested. Thus, among the mosquitocidal strains of B. sphaericus we identified a strain, IAB-59, which was toxic to several Culex colonies that were highly resistant to commercial strains 2362 and 1593. Our analysis also indicated that strain IAB-59 may possess other larvicidal factors. These results could have important implications for the development of resistance management strategies for area-wide mosquito control programs based on the use of B. sphaericus preparations.

Beneficial effect of post -thawing osmoconditioning on the recovery of cryopreserved coffee (Coffea arabica L.) seeds

Osmoconditioning-controlled rehydration of seeds in a solution with low osmotic potential -has been shown to reinvigorate aged seeds. The present work aimed at investigating the effect of osmoconditioning on the germination of cryopreserved seeds of Coffea arabica, whose viability and vigour are drastically affected by cryopreservation. For cryopreservation, seeds were desiccated to 0.21 g H2O/g dw, cooled at 1 degree C/min to -50 degree C, then immersed rapidly in liquid nitrogen. After rapid rewarming, seeds were osmoconditioned for 1 to 6 weeks using solutions with osmotic potentials between -1 and -4 MPa. The time to produce half of the final percentage of normal seedlings, T50, was about three fold lower with osmoconditioned seeds than with non-osmoconditioned seeds (12-14 d vs 36 d). Moreover, after a 6-week osmoconditioning treatment with solutions with osmotic potential of -1 and -1.25 MPa, the percentage of seedlings recovered from cryopreserved seeds was 64-74%, against 13-16% only for cryopreserved seeds which were not osmoconditioned.

Uniform Supersonic Expansion for FTIR Absorption Spectroscopy: The nu(5) Band of (NO)(2) at 26 K

A high-resolution Fourier transform interferometer (Bruker IFS 120 HR) was combined with a uniform supersonic expansion produced by means of axisymmetric Laval nozzles. The geometry profile of the nozzle enabled us to work under precise thermodynamic and kinetic conditions. The effect of the cooling rate of different nozzles on cluster nucleation is illustrated. The experimental sensitivity was tested by recording the nu(5) band of (NO)(2) at 26 K. Copyright 2000 Academic Press.

Two skeletal alpha-tropomyosin transcripts with distinct 3'UTR have different temporal and spatial patterns of expression in the striated muscle lineages of Xenopus laevis

The Xenopus laevis alpha-tropomyosin (TM) gene, like its vertebrates counterparts, encodes muscle and non-muscle isoforms through two promoters and alternatively spliced exons. In the present study we describe a cDNA clone (XTMalpha7) encoding a skeletal muscle isoform of the gene that differs from the previously described skeletal TM transcript (XTMalpha2) by its 3'UTR sequence. The two skeletal alpha-TM encoding mRNAs are generated through distinct 3'end processing using different polyA signals and distinct patterns of exon splicing. Using RNAse protection and RNA in situ hybridization, we have analysed the developmental and spatial expression of the two transcripts. Both are expressed in the embryo, but XTMalpha7 is by far the most prevalent of the two. In contrast, only XTMalpha2 is expressed in adult striated muscle tissues. In the embryo, the spatial expression of XTMalpha7 is restricted to the somites whereas XTMalpha2 is expressed in both somites and embryonic heart.

Production of Cry11A and Cry11Ba toxins in Bacillus sphaericus confers toxicity towards Aedes aegypti and resistant Culex populations

Cry11A from Bacillus thuringiensis subsp. israelensis and Cry11Ba from Bacillus thuringiensis subsp. jegathesan were introduced, separately and in combination, into the chromosome of Bacillus sphaericus 2297 by in vivo recombination. Two loci on the B. sphaericus chromosome were chosen as target sites for recombination: the binary toxin locus and the gene encoding the 36-kDa protease that may be responsible for the cleavage of the Mtx protein. Disruption of the protease gene did not increase the larvicidal activity of the recombinant strain against Aedes aegypti and Culex pipiens. Synthesis of the Cry11A and Cry11Ba toxins made the recombinant strains toxic to A. aegypti larvae to which the parental strain was not toxic. The strain containing Cry11Ba was more toxic than strains containing the added Cry11A or both Cry11A and Cry11Ba. The production of the two toxins together with the binary toxin did not significantly increase the toxicity of the recombinant strain to susceptible C. pipiens larvae. However, the production of Cry11A and/or Cry11Ba partially overcame the resistance of C. pipiens SPHAE and Culex quinquefasciatus GeoR to B. sphaericus strain 2297.

Updating the H-antigen classification of Bacillus thuringiensis

The classification of Bacillus thuringiensis strains has been revised and updated based on flagellar antigens which have been in use for many years. Sixty-nine serotypes and 13 sub-antigenic groups have now been identified, giving 82 serovars among the 3500 B. thuringiensis isolates of the IEBC Collection. The number of serovars has gradually increased with the total number of strains. The biochemical characters used have also been investigated and their value assessed for identification of B. thuringiensis at the subspecies level. A crystal analysis was carried out in terms of morphology, delta-endotoxin profiles and larvicidal activity for the newly identified serovars. It was found that atypical crystals, some with novel components, are becoming more common. No insect susceptible to these serovars has been discovered among known target species. The number of cross-reacting H-antigens among B. cereus strains is increasing and may be of biological significance.

Bacterial control of mosquito larvae: investigation of stability of Bacillus thuringiensis var. israelensis and Bacillus sphaericus standard powders

Bacillus thuringiensis var. israelensis and Bacillus sphaericus products were assayed against their respective reference powders IPS82 and SPH88. Since their production in 1982 and 1988, the potency and larvicidal activity of these standard powders have been regularly checked on their test insects Aedes aegypti (for IPS82) or Culex pipiens (for SPH88). Over the 16-year evaluation period of IPS82 and 10-year evaluation period of SPH88, their potencies were considered stable. The global mean of each year's mean showed a coefficient of variation of less than 20%. Larval rearing was the most important factor in the reproducibility of the bioassay, although some variation also originated from the person performing the bioassay. This study demonstrated that the SPH88 standard could be kept in a stock suspension at 4 degrees C for 3 years without loss of potency. Moreover, after 9 years of storage in suspension, only a 2-fold decrease in the potency of SPH88 was detected.

The introduction into bacillus sphaericus of the Bacillus thuringiensis subsp. medellin Cyt1Ab1 gene results in higher susceptibility of resistant mosquito larva populations to B. sphaericus

The fragment containing the gene encoding the cytolytic Cyt1Ab1 protein from Bacillus thuringiensis subsp. medellin and its flanking sequences (I. Thiery, A. Delécluse, M. C. Tamayo, and S. Orduz, Appl. Environ. Microbiol. 63:468-473, 1997) was introduced into Bacillus sphaericus toxic strains 2362, 2297, and Iab872 by electroporation with the shuttle vector pMK3. Only small amounts of the protein were produced in recombinant strains 2362 and Iab872. The protein was detected in these strains only by Western blotting and immunodetection with antibody raised against Cyt1Ab1 protein. Large amounts of Cyt1Ab1 protein were produced in B. sphaericus recombinant strain 2297, and there was an additional crystal, other than that of the binary toxin, within the exosporium. The production of the Cyt1Ab1 protein in addition to the binary toxin did not increase the larvicidal activity of the B. sphaericus recombinant strain against susceptible mosquito populations of Culex pipiens or Aedes aegypti. However, it partially restored (10 to 20 times) susceptibility of the resistant mosquito populations of C. pipiens (SPHAE) and Culex quinquefasciatus (GeoR) to the binary toxin. The Cyt1Ab1 protein produced in recombinant B. thuringiensis SPL407(pcyt1Ab1) was synthesized in two types of crystal-one round and with various dense areas, surrounded by an envelope, and the other a regular cuboid crystal, very similar to that found in the B. sphaericus recombinant strain.

Phylogenetic analysis of chloroplast DNA variation in Coffea L

The trnL-trnF intergenic spacer of cpDNA has been sequenced from 38 tree samples representing 23 Coffea taxa and the related genus Psilanthus. These sequences were used for phylogenetic reconstruction using parsimony analyses. The results suggest a radial mode of speciation and a recent origin in Africa for the genus Coffea. Phylogenetic relationships inferred from the cpDNA analysis suggest several major clades, which present a strong geographical correspondence (i.e., west Africa, central Africa, east Africa, and Madagascar). The overall results agree well with the phylogeny previously inferred from nuclear genome data. However, several inconsistencies are observed among taxa endemic to west Africa, suggesting the occurrence of introgressive hybridization. Evidence is also obtained for the genetic origin of the allotetraploid species C. arabica.

Comparative flow cytometric estimation of nuclear DNA content in oil palm (Elaeis guineensis Jacq) tissue cultures and seed-derived plants

Flow cytometric analysis performed on two different crosses of dura×pisifera oil palm gave an accurate estimation of nuclear DNA content. The genome size of Elaeis guineensis was found to be 2C=3.76±0.09 pg and therefore ca. 3.4×10⁹ bp. Embryogenic calli and plants showed the same ploidy level, but the measured 2C DNA values differed significantly. No variation in the ploidy level between three different types of calli originating from foliar explants, namely nodular compact callus, fast-growing callus and friable callus was observed. Since fast-growing callus (FGC), already identified as a source of `mantled' phenotype variants, did not show any difference in their ploidy level, these results are consistent with the hypothesis of an epigenetic origin for this type of somaclonal variant.

Inheritance and restriction fragment length polymorphism of chloroplast DNA in the genus Coffea L

CpDNA variation among 52 tree samples belonging to 25 different taxa of Coffea and two species of Psilanthus was assessed by RFLP analysis on both the total chloroplast genome and the atpB-rbcL intergenic region. Twelve variable characters were distinguished allowing the identification of 12 different plastomes. The low sequence divergence observed might suggest that Coffea is a young genus. The results were in contradiction with the present classification into two genera. Additionally, cpDNA inheritance was studied in interspecific hybrids between C. arabica and C. canephora, and in an intraspecific progeny of C. canephora, using PCR-based markers. Both studies showed exclusively maternal inheritance of cpDNA.

Reliable flow cytometric estimation of nuclear DNA content in coffee trees

Flow cytometry gave high resolution of genome size in two coffee taxa (Coffea liberica dewevrei and C. pseudozanguebariae). Propidium iodide (PI) and Petunia hybrida were used as dye and internal standard, respectively. Proportionally between the DNA content and the digitized fluorescence signal was checked. Five main results were evident. First, optimal experimental conditions were established for peak location estimation (mean or mode), staining time (at least 2 minutes), high voltage (557 V) for the photomultiplier tube (PMT), and PI concentration (333 micrograms/ml). Second, a parameterization of the effects of high voltage and PI concentration were deduced from curve fitting. Third, two biases in DNA content estimation were recorded for high voltage and PI concentration, and were minimized. Fourth, the genome sizes of C. liberica dewevrei and C. pseudozanguebariae were estimated with accuracy 2C = 1.421 +/- 0.005 pg and 2C = 1.129 +/- 0.005 pg, respectively. Fifth, between-genotype variance was emphasized within each taxon.

Nuclear DNA content in the subgenus Coffea (Rubiaceae): inter- and intra-specific variation in African species

Flow cytometry has been used to estimate nuclear DNA content of 13 Coffea species (Rubiaceae) native to Africa. Twelve diploid (2n = 22) and one tetraploid (C. arabica, 2n = 44) species were investigated. Isolated nuclei from 77 genotypes were stained with propidium iodide (PI; not base specific). Thirty-nine genotypes were stained with 4′,6-diamidino-2-phenylindole (DAPI; AT specific). Nuclear DNA content (2C values), estimated with PI, ranged from 0.95 to 1.78 pg. By aggregative clustering, three groups of accessions with increasing DNA content were identified. Three species, namely C. sessiliflora, C. racemosa, and C. pseudozanguebariae, had a low DNA content (0.90 – 1.30 pg). Three species, namely C. eugenioides, C. stenophylla, and C. sp. F, were exclusively found in the intermediate group (1.31 – 1.60 pg). The remaining species were distributed between the intermediate group and the last group (1.61 – 1.80 pg). The values determined for the Coffea species are compared, inter- and intra-specifically, to those of other angiosperm species. The observed differences are discussed according to the ecogeographic origin of the species, their phenological characteristics, and the fertility of the F1 interspecific hybrids. Key words: Africa, Coffea, flow cytometry, nuclear DNA content, genome evolution.

First controlled progenies checked by isozymic markers in cultivated yams Dioscorea cayenensis-rotundata

As tested progeny have never been obtained, breeding studies on African yams (Dioscorea cayenensisrotundata) are scarce. We report here the first progenies checked by isoenzyme markers. This was made possible by the choice of well-known genitors [one male (cv Zrezrou) and three females (cvs 'Sopéré', 'Dahomey' and 'C 20')] and special hybridization conditions. Six enzymatic systems [esterase (EST), isocitrate dehydrogenase (ICD), malate dehydrogenase (MDH), 6-phosphogluconate dehydrogenase (6PGD), shikimate dehydrogenase (SDH), and phosphoglucoisomerase (PGI)] were used to check the progenies and detect outbreeding. Despite the small number of progeny, it was possible to provide information on the genetics of the isoenzymatic systems.

Inclusion bodies and crystals of Bacillus sphaericus mosquitocidal proteins expressed in various bacterial hosts

Mosquitocidal proteins of 42 and 51 kDa from Bacillus sphaericus were produced in acrystallogenic B. sphaericus and B. subtilis strains. In both species, transformants containing each protein expressed individually were non-toxic for mosquito larvae and produced small inclusions which did not have a crystalline ultrastructure. When both components of the binary toxin were expressed together, toxicity was restored: oval and round amorphous inclusions were produced in B. subtilis, and typical native-type crystals were synthesized in B. sphaericus. In B. subtilis, native-type crystals were produced only when the two components of the binary toxin were synthesized as a 93-kDa fusion protein.

Characterization and toxicity to mosquito larvae of four Bacillus sphaericus strains isolated from Brazilian soils

Four Bacillus sphaericus strains, S1, S2, S5, and L2, isolated from Brazilian soils, were found to be toxic to larvae of the mosquitoes Culex pipiens and Anopheles stephensi at a level similar to that of strain 2362 which is now used operationally. Like strain 2362, the four strains belonged to the serotype H5 and produced major proteins of apparent molecular weights of 125, 110, 56, and 43 kDa. These latter two proteins were immunologically related to toxins of the same molecular weight as B. sphaericus 2362. Although the four Brazilian strains were very similar to strain 2362, gas chromatography analysis of the fatty acids revealed that these strains were different from strain 2362 and from each other, except for a possible similarity between strains S1 and S5.

Cellular fatty acid analysis as a potential tool for predicting mosquitocidal activity of Bacillus sphaericus strains

Gas-liquid chromatography of fatty acid methyl esters and numerical analysis were carried out with 114 Bacillus sphaericus strains. Since only two clusters harbored mosquitocidal strains, this technique could be developed in screening programs to limit bioassays on mosquito larvae. It also allows differentiation of highly homologous strains.

Serum lipid abnormalities in heart transplant recipients: predominance of HDL2-like particles in the HDL pattern

Accelerated coronary atherosclerosis is a major risk limiting long-term survival after heart transplantation and is commonly associated with dyslipoproteinemia even in subjects who were not dyslipoproteinemic before intervention. The purpose of this study was to analyse the abnormalities in the lipid profiles of 2 different groups of heart-transplanted males: 18 subjects with underlying ischemic heart disease (IHD) and 19 subjects with non-obstructive cardiomyopathy of unknown aetiology (CM). Both groups were compared to 33 healthy males. All patients were under immunosuppressive therapy including prednisone, cyclosporin A and azathioprine. A moderate hyperlipidemia was found in all transplant recipients, associated with high HDL-cholesterol concentrations in the CM group (1.80 +/- 0.37 vs. 1.29 +/- 0.23 mmol/l) and normal HDL-cholesterol levels in the IHD group (1.40 +/- 0.23 mmol/l). HDL subfractionation showed a marked increase in HDL2-cholesterol (CM: 1.12 +/- 0.32; IHD: 0.69 +/- 0.28; control: 0.40 +/- 0.17 mmol/l) while HDL3-cholesterol was significantly lower than in the control group. Analysis of HDL particle sizes showed in all transplant subjects an increase of an intermediate size particle HDL2a (diameter 9.0 +/- 0.10 nm) which is a minor form in control subjects. In the CM group, both the common HDL2b (10.2 +/- 0.13 nm) and HDL2a were abundant in 13 of 17 patients. The pattern was more heterogeneous in the IHD group but witnessed to a high frequency of HDL2a particles either alone (5/14) or associated with larger HDL2b (4/14) or with small HDL3 (4/14).(ABSTRACT TRUNCATED AT 250 WORDS)

Another Bacillus sphaericus serotype harbouring strains very toxic to mosquito larvae: serotype H6

Ten isolates of Bacillus sphaericus from Ghana, very toxic to mosquito larvae, have been identified as belonging to serotype H6. These isolates can be represented by the head-group strain IAB59. They form crystals at the sporulation stage. Their larvicidal effect on Culex pipiens and Anopheles stephensi larvae is as high as that of the most toxic strains already known, e.g. 1593 and 2362 (serotype H5a,5b) and 2297 (serotype H25). Spore-crystal extracts of all these strains contain a 43-Kd polypeptide immunologically related to the 43-Kd polypeptide from strain 2362 described by other authors.