Stable resistance against the leaf miner <Emphasis Type="Italic">Leucoptera coffeella</Emphasis> expressed by genetically transformed <Emphasis Type="Italic">Coffea canephora</Emphasis> in a pluriannual field experiment in French Guiana

Summary A pluriannual field trial of transgenic clones of Coffea canephora (the Robusta coffee tree) transformed for resistance to the lepidopteran coffee leaf miner Leucoptera coffeella was installed in French Guiana. Fifty-eight transformed clones produced by transformation of the C. canephora clone 126 were planted. They were harbouring the pEF1α constitutive promoter of Arabidopsis thaliana controlling either the Bacillus thuringiensis native gene for the cry1Ac insecticidal protein (eight clones) or a synthetic cry1Ac gene (53 clones). The vectors for the transformation were a strain of the bacterium Agrobacterium tumefaciens and one of Agrobacterium rhizogenes. The transformed clones were generally independent, presenting different integration patterns of the genetic construct. Four randomly distributed groups of five plants per transformed clone were planted along with 60 untransformed control trees. Over a 4-year period after plantation six releases of L. coffeella were performed. Mines on the leaves are the marks of larvae development and were counted on plants. A majority of the independent transformed clones harbouring the synthetic gene and transformed by the strain of A. tumefaciens displayed constantly much less mines than the control, therefore expressing a stable resistance. The need for complementary research is presented.     

Environmental drivers of community diversity in a neotropical urban landscape: a multi-scale analysis

Context

Many aquatic communities are linked by the aerial dispersal of multiple, interacting species and are thus structured by processes occurring in both the aquatic and terrestrial compartments of the ecosystem.

Objectives

To evaluate the environmental factors shaping the aquatic macroinvertebrate communities associated with tank bromeliads in an urban landscape.

Methods

Thirty-two bromeliads were georeferenced to assess the spatial distribution of the aquatic meta-habitat in one city. The relative influence of the aquatic and terrestrial habitats on the structure of macroinvertebrate communities was analyzed at four spatial scales (radius = 10, 30, 50, and 70 m) using redundancy analyses.

Results

We sorted 18,352 aquatic macroinvertebrates into 29 taxa. Water volume and the amount of organic matter explained a significant part of the taxa variance, regardless of spatial scale. The remaining variance was explained by the meta-habitat size (i.e., the water volume for all of the bromeliads within a given surface area), the distance to the nearest building at small scales, and the surface area of buildings plus ground cover at larger scales. At small scales, the meta-habitat size influenced the two most frequent mosquito species in opposite ways, suggesting spatial competition and coexistence. Greater vegetation cover favored the presence of a top predator.

Conclusions

The size of the meta-habitat and urban landscape characteristics influence the structure of aquatic communities in tank bromeliads, including mosquito larval abundance. Modifications to this landscape will affect both the terrestrial and aquatic compartments of the urban ecosystem, offering prospects for mosquito management during urban planning.

     

小麦EST—SSRs分子标记的特性及其遗传作图

为了解普通小麦EST来源的微卫星的多样性,从大约1000个包含微卫星的ESTs中设计了300对引物,研究和评估了它们的多态性水平,并且将多态性标记加入到现有的遗传图谱中。在五种不同类型的重复单元中,三个碱基的重复单元出现最多,占到77％。几乎所有的EST—SSRs标记（99．3％）的重复单元都含有G-C碱基对。37．4％的微卫星都是四次重复。对于扩增和多态性,300对引物中有60对没有扩增,21．3％的扩增引物没能产生预期的扩增片断。58％的标记至少在所用8个材料的一个中显示出多态性。W7984和Opata组合表现出最高的多态性水平。大多数普通小麦EST—SSRs标记的重复次数小于10,并且4次重复是最为普遍的。81个新的EST—SSR位点被添加到两个已有的参照遗传图谱中（62个加到ITMI,19个加到CTCS）。研究结果表明小麦EST-SSRs标记展示了一些不同于基因组微卫星的特异特征,在标记发展和其他遗传应用中,这就使得它们能够成为一种非常有价值的资源。     

Spirometric performance in Belgian Blue calves: I. Effects on economic losses due to the bovine respiratory disease complex

The aim of this study was to determine whether high spirometric performances in calves are associated with low economic losses due to the bovine respiratory disease complex (BRDC). Five spirometric variables (SV) were measured in 909 double-muscled Belgian Blue calves from 15 to 60 d of age. Afterward, calves were monitored for 6 mo to determine whether they developed BRDC and to determine the costs due to BRDC (i.e., medicine costs and veterinarians' fees, plus estimated financial losses due to mortality in case of death). To analyze the effects of spirometric performances on BRDC cost, a fixed linear model was used for each SV. In addition to SV, each model included the effects of sex, dam's parity, vaccination status, muscular development score, herd-period, and BW. Only herd-period and the maximal ventilation and the vital capacity had significant effects on costs due to BRDC, indicating that these two SV are major physiological determinants of economic losses associated with BRDC. Accordingly, it is assumed that an amelioration of maximal ventilation and vital capacity could result in increased resistance to BRDC in calves.     

Hormonal and Metabolic Profiles of High-yielding Dairy Cows Prior to Ovarian Cyst formation or First Ovulation Post Partum

The present study aimed to investigate the pathogenesis of cystic ovarian disease (COD) in high-yielding dairy cows postpartum (pp). Hormonal and metabolic profiles during the first 3 weeks pp as well as during the final week prior to ovulation/cyst formation, were compared between dairy cows that developed either an ovulatory follicle (OV) or a cyst (CYST) < day 60 pp. Thirty-four lactations of 28 high-yielding (9500 kg/305 days) Holstein-Friesian dairy cows were studied. Ovaries of cows were scanned twice a week from day 10 pp on, until ovulation/cyst formation. Milk yield data, body condition scores and blood samples, for determination of oestradiol-17beta, insulin, beta-OH-butyrate and non-esterified fatty acids, were collected simultaneously. Milk samples for progesterone analysis were collected daily. Four lactations were excluded from further analysis because of irregular pp ovarian cyclicity, excluding COD. Eight lactations (26.7%) developed a cyst, while 22 lactations ovulated < days 60 pp. Ovulation and cyst formation occurred at similar times pp. Metabolic and hormonal profiles did not differ between CYST and OV lactations during the first 3 weeks pp. In the final week prior to cyst formation/ovulation, insulin concentrations were lower in CYST than in OV lactations while no differences were observed for any of the other parameters tested. In two lactations, cyst formation was preceded by suprabasal progesterone and increased oestradiol-17beta concentrations. These results suggest that cyst formation in high-yielding dairy cows pp is associated with lower insulin levels but not with other distinct hormonal and metabolic alterations. However from this study, we cannot exclude the involvement of subtle hormonal and metabolic changes in the pathogenesis of ovarian cysts. Suprabasal progesterone, and altered oestradiol-17beta concentrations, seem to play a minor role in cyst formation.     

RAPD Characterization of Single Females of the Root-knot Nematodes, Meloidogyne Spp.

Random amplified polymorphic DNA fingerprinting was performed on single females of root-knot nematodes, Meloidogyne spp., using a new procedure for DNA isolation. One-fourth of the total DNA amount isolated from a single female proved to be sufficient as a template in a polymerase chain reaction. Electrophoretic patterns of the amplified fragments were reproducible between replicates from a single female or sister females from the same progeny, and identical to those obtained with genomic DNA purified from a large number of nematodes. Moreover, a comparative analysis over three successive generations showed stability of the amplification patterns, thus demonstrating the utility of this procedure for epidemiological and ecological studies on root-knot nematodes.     

Prepartum teat apex colonization with Staphylococcus chromogenes in dairy heifers is associated with low somatic cell count in early lactation

A high number of dairy heifers freshen with udder health problems. The prevalence of teat apex colonization (TAC) with Staphylococcus chromogenes, one of the most widespread coagulase-negative staphylococci (CNS) in milk samples from freshly calved dairy heifers, was measured cross-sectionally in non-lactating heifers on eight commercial dairy farms in Belgium. The influence of age on this prevalence, and the association between teat apex colonization with S. chromogenes prepartum and quarter milk somatic cell count (SCC) in early lactation were studied. In total, 492 teat apices were sampled from 123 heifers. The age of the heifers varied from 8 to 34 months. Overall, 20% of the heifers had at least one teat apex colonized with S. chromogenes. Of all teats sampled, 10% were colonized with S. chromogenes. The chance of having at least one teat apex colonized with S. chromogenes increased with age of the heifer. The presence of prepartum teat apex colonization with S. chromogenes was not associated with intramammary infection (IMI) early postpartum with the same bacterium. On the contrary, teat apex colonization with S. chromogenes prepartum appeared to protect quarters in the first few days of lactation from having somatic cell count >or=200000cells/ml milk, commonly accepted as the threshold for intramammary infection.     

Genetic variability in French dog breeds assessed by pedigree data

Pedigree data of nine French dog breeds, namely Barbet (BAR), Basset fauve de Bretagne (BAF), Beauceron (BEN), Berger des Pyrénées (BRP), Bouledogue Français (BUF), Braque Saint‐Germain (BQG), Dogue de Bordeaux (DOB), Epagneul Breton (EPB) and Montagne des Pyrénées (MOP), were analysed. The effective numbers of ancestors of dogs born from 1997 to 2001 were equal to 6.7 (BAR), 40.2 (BAF), 36.5 (BEN), 16.0 (BRP), 37.0 (BUF), 13.1 (BQG), 28.9 (DOB), 33.3 (EPB) and 34.0 (MOP). The expected contributions of the major ancestors were found to be highly unbalanced in the EPB and BRP. The average coefficient of inbreeding of dogs born from 1997 to 2001 with both parents known was equal to 12.4% (BAR), 3.9% (BAF), 5.4% (BEN), 7.2% (BRP), 3.3% (BUF), 6.0% (BQG), 4.1% (DOB), 4.5% (EPB) and 4.0% (MOP). These values were found to be significantly higher than the average coefficient of kinship between the male and the female parents of these animals, except in the BAR and BQG, revealing an usual practice of mating between related animals. The results are discussed in relation with the demographic situation and the use of each breed. The method used to class an endangered breed and the ways to preserve the genetic variability, when necessary, are evoked.     

Characterisation of camel breeding practices in the Ansongo Region,Mali

Despite its importance in Mali’s economy, camel breeding in the country remains poorly documented, impeding effective policy-making in this regard. This study consisted in a 3-month survey and aimed at characterising camel breeding systems in Ansongo, in the region of Gao, Mali. It highlights the diversity of strategies adopted by breeders and their evolutions. Supplementary feeding and veterinary care were seldom practised. In zones close to the Niger River, cattle were substituted to camels. Transhumance routes also are modified but mobility keeps its vital role in the breeding system. Important differences within the study region in the classification of camel breeds have been reported that will influence the implementation of a collective action for animal genetic improvement. The improvement goals should take the actual management, including mobility and the mixed nature of the herds into account.     

An insight into population structure and gene flow within pure‐bred cats

Investigation of genetic structure on the basis of pedigree information requires indicators adapted to the specific context of the populations studied. On the basis of pedigree‐based estimates of diversity, we analysed genetic diversity, mating practices and gene flow among eight cat populations raised in France, five of them being single breeds and three consisting of breed groups with varieties that may interbreed. When computed on the basis of coancestry rate, effective population sizes ranged from 127 to 1406, while the contribution of founders from other breeds ranged from 0.7 to 16.4%. In the five breeds, F_IS ranged between 0.96 and 1.83%, with this result being related to mating practices such as close inbreeding (on average 5% of individuals being inbred within two generations). Within the three groups of varieties studied, F_IT ranged from 1.59 to 3%, while values were estimated between 0.04 and 0.91%, which was linked to various amounts of gene exchanges between subpopulations at the parental level. The results indicate that cat breeds constitute populations submitted to low selection intensity, contrasting with relatively high individual inbreeding level caused by close inbreeding practices.