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71.
H. Benbouza J. M. Lacape J. M. Jacquemin B. Courtois F. B. H. Diouf D. Sarr N. Konan J. P. Baudoin G. Mergeai 《Molecular breeding : new strategies in plant improvement》2010,25(2):273-286
In order to select genotypes of Gossypium hirsutum genetically balanced and expressing the low-gossypol seed & high-gossypol plant trait introgressed from the Australian wild diploid species G. sturtianum, the [(G. hirsutum × G. raimondii)2 × G. sturtianum] triple hybrid was backcrossed to G. hirsutum and autopollinated to produce backcross and selfed progenies. Two hundred and six mapped SSR markers of G. hirsutum were used to monitor the introgression of SSR alleles specific to G. sturtianum and G. raimondii in the selected progenies. A high level of heterozygosity, varying from 25 to 100%, was observed for all G. sturtianum-specific SSR markers conserved in the most advanced progenies. These results indicate the existence of segregation distortion
factors that are associated with the genes controlling the researched trait. This study represents a starting point to map
the genes involved in the expression of the trait and better understand its genetic determinism. 相似文献
72.
In Situ Dynamics of Microbial Communities during Decomposition of Wheat, Rape, and Alfalfa Residues 总被引:4,自引:0,他引:4
Noémie Pascault Lauric Cécillon Olivier Mathieu Catherine Hénault Amadou Sarr Jean Lévêque Pascal Farcy Lionel Ranjard Pierre-Alain Maron 《Microbial ecology》2010,60(4):816-828
Microbial communities are of major importance in the decomposition of soil organic matter. However, the identities and dynamics of the populations involved are still poorly documented. We investigated, in an 11-month field experiment, how the initial biochemical quality of crop residues could lead to specific decomposition patterns, linking biochemical changes undergone by the crop residues to the respiration, biomass, and genetic structure of the soil microbial communities. Wheat, alfalfa, and rape residues were incorporated into the 0–15 cm layer of the soil of field plots by tilling. Biochemical changes in the residues occurring during degradation were assessed by near-infrared spectroscopy. Qualitative modifications in the genetic structure of the bacterial communities were determined by bacterial-automated ribosomal intergenic spacer analysis. Bacterial diversity in the three crop residues at early and late stages of decomposition process was further analyzed from a molecular inventory of the 16S rDNA. The decomposition of plant residues in croplands was shown to involve specific biochemical characteristics and microbial community dynamics which were clearly related to the quality of the organic inputs. Decay stage and seasonal shifts occurred by replacement of copiotrophic bacterial groups such as proteobacteria successful on younger residues with those successful on more extensively decayed material such as Actinobacteria. However, relative abundance of proteobacteria depended greatly on the composition of the residues, with a gradient observed from alfalfa to wheat, suggesting that this bacterial group may represent a good indicator of crop residues degradability and modifications during the decomposition process. 相似文献
73.
Sarr JB Pelleau S Toly C Guitard J Konaté L Deloron P Garcia A Migot-Nabias F 《Microbes and infection / Institut Pasteur》2006,8(5):1260-1268
The evidence of protection afforded by red blood cell polymorphisms against either clinical malaria or Plasmodium falciparum blood levels varies with the study site and the type of malaria transmission. Nevertheless, no clear implication of an antibody-related effect has yet been established in the protection related to red blood cell polymorphisms. We performed a prospective study, where plasma IgG and IgG subclasses directed to recombinant proteins from the merozoite surface protein 2 (MSP2/3D7 and MSP2/FC27) and the ring-infected erythrocyte surface antigen (RESA) were determined in a cohort of 413 Senegalese children before the annual malaria transmission season. The antibody response was dependent on age, and to a lesser extent, on the village of residence. IgG3 responders to all proteins, IgG responders to RESA and MSP2/3D7, as well as IgG2 to RESA and IgG1 responders to MSP2/3D7, presented enhanced mean values of parasite density, as evaluated during an 18-month follow-up. The levels of IgG and IgG3 to MSP2/3D7 were negatively associated with the risk of occurrence of a malaria attack during the following transmission season. Compared to normal children, sickle cell trait carriers presented lower levels of IgG to MSP2/3D7. Similarly, G6PD A- girls had lower levels of IgG and IgG3 to MSP2/FC27 than did G6PD normal girls. The impact of these particular genetic polymorphisms on the modulation of the antibody response is discussed. 相似文献
74.
Eric Sylvain Badji Aly Diallo Moustapha Bassimb Sagna Oumar Sarr Mariama Dalanda Diallo Daouda Ngom Aliou Guiss 《African Journal of Ecology》2021,59(1):178-189
This work consisted of analysing the impact of protection on the Widou Thiengoly's grasslands structure. Data were collected from three selected sites by the quadrat point methodology, consisting of reading the herbaceous on a 10 m line. These sites were the 2013 defended plot (site A), the 2009 semi‐protected plot (site B) and the unprotected grazing areas or off plot (site C). The results revealed a floristic composition of 45 species, belonging to 34 genera and 17 botanical families. The number of species identified was 28 in site A, 31 in site B and 29 in site C. Despite a certain similarity noted in the number of species, the herbaceous vegetation was more balanced in 2013 plot than in 2009 plot and in off plot where it tended to be homogeneous. The herbaceous cover in October 2015 was 99.8% in the 2013 plot; 98.8% in the 2009 plot; and 96.8% in the unprotected sites. The vertical stratification of herbaceous cover showed a better development at the intermediate strata (between 20 cm and 50 cm) in all the sites except in off plot where small grasses dominated. In this study, protection improved the specific balance, while semi‐protection had a positive effect on the specific richness and growth of the grasses. 相似文献
75.
C. Parisod C. Definod A. Sarr N. Arrigo F. Felber 《Journal of evolutionary biology》2013,26(1):223-228
Introgression of sequences from crop species in wild relatives is of fundamental and practical concern. Here, we address gene flow between cultivated wheat and its widespread polyploid relative, Aegilops triuncialis, using 12 EST‐SSR markers mapped on wheat chromosomes. The presence of wheat diagnostic alleles in natural populations of the barbed goatgrass growing in proximity to cultivated fields highlights that substantial gene flow occurred when both species coexisted. Furthermore, loci from the A subgenome of wheat were significantly less introgressed than sequences from other subgenomes, indicating differential introgression into Ae. triuncialis. Gene flow between such species sharing nonhomeologous chromosomes addresses the evolutionary outcomes of hybridization and may be important for efficient gene containment. 相似文献
76.
Inter-laboratory evaluation of the ISO standard 11063 "Soil quality - Method to directly extract DNA from soil samples" 总被引:1,自引:0,他引:1
Petric I Philippot L Abbate C Bispo A Chesnot T Hallin S Laval K Lebeau T Lemanceau P Leyval C Lindström K Pandard P Romero E Sarr A Schloter M Simonet P Smalla K Wilke BM Martin-Laurent F 《Journal of microbiological methods》2011,84(3):454-460
Extracting DNA directly from micro-organisms living in soil is a crucial step for the molecular analysis of soil microbial communities. However, the use of a plethora of different soil DNA extraction protocols, each with its own bias, makes accurate data comparison difficult. To overcome this problem, a method for soil DNA extraction was proposed to the International Organization for Standardization (ISO) in 2006. This method was evaluated by 13 independent European laboratories actively participating in national and international ring tests. The reproducibility of the standardized method for molecular analyses was evaluated by comparing the amount of DNA extracted, as well as the abundance and genetic structure of the total bacterial community in the DNA extracted from 12 different soils by the 13 laboratories. High quality DNA was successfully extracted from all 12 soils, despite different physical and chemical characteristics and a range of origins from arable soils, through forests to industrial sites. Quantification of the 16S rRNA gene abundances by real time PCR and analysis of the total bacterial community structure by automated ribosomal intergenic spacer analysis (A-RISA) showed acceptable to good levels of reproducibility. Based on the results of both ring-tests, the method was unanimously approved by the ISO as an international standard method and the normative protocol will now be disseminated within the scientific community. Standardization of a soil DNA extraction method will improve data comparison, facilitating our understanding of soil microbial diversity and soil quality monitoring. 相似文献
77.
Cowpea [Vigna unguiculata (L.) Walp.] is an important legume crop and yet its rhizobia have not been well characterized in many areas. In the present study, sequence analysis of the bacterial 16S-23S rRNA internal transcribed spacer (ITS) region was performed to characterize genetically 76 indigenous cowpea rhizobia from five different geographic regions (Okinawa, Miyazaki, Kyoto, Fukushima and Hokkaido) of Japan. The sequence analysis clustered all isolates in the genus Bradyrhizobium. They were conspecific with B. japonicum, B. yuanmingense, B. elkanii and Bradyrhizobium sp., although none of them grouped with B. liaoningense, B. canariense, B. betae or B. iriomotense. B. yuanmingense was only isolated from the southern region (Okinawa) where it achieved the highest frequency of 69%. B. japonicum was predominant at Miyazaki, Fukushima and Hokkaido with more than 60% of the isolates. B. elkanii was mainly recorded in the southern (Okinawa: 31%, Miyazaki: 33%) and middle (Kyoto: 33%) regions. This species was present at a very low frequency in Fukushima and absent in Hokkaido in the northern area. Bradyrhizobium sp. like-strains were absent in the southern part (Okinawa, Miyazaki) but were concentrated either in the middle regions with 67% of Kyoto isolates and 28% of Fukushima isolates, and in the northern region with 40% of the Hokkaido isolates. This study revealed a geographical distribution of cowpea bradyrhizobia which seemed to be related to the differences in the environmental characteristics (soil type and soil pH, temperature, climate, moisture) of the different regions in Japan. 相似文献
78.
Marima Sarr Maryam Tidjani Alou Jeremy Delerce Saber Khelaifia Nafissatou Diagne Aldiouma Diallo Hubert Bassene Ludivine Brchard Vincent Bossi Babacar Mbaye Jean-Christophe Lagier Anthony Levasseur Cheikh Sokhna Matthieu Million Didier Raoult 《PLoS neglected tropical diseases》2021,15(6)
BackgroundSevere acute malnutrition (SAM) is a major public health problem affecting children under the age of five in many low- and middle-income countries, and its resolution would contribute towards achieving the several sustainable development goals. The etiology of SAM is pluri-factorial, including delayed maturation of the gut microbiota, suboptimal feeding practices and dysfunctional breastfeeding. The recent serendipitous detection of Listeria monocytogenes in the breast milk of Malian women, in contrast to French women, suggests a possible association with SAM.Methodology/ Principal findingsTo investigate the possible association of L. monocytogenes carriage in breast milk and SAM, a case-control study was performed in Senegal, with subjects recruited from two areas. Using 16S amplicon sequencing, a culture independent method, 100% (152/152) of the mothers were positive for L. monocytogenes in their breast milk while qPCR analysis gave lower recovery rates. Interestingly, after enrichment in Fraser broth and seeding on PALCALM agar, all 10 isolated strains were isolated from the milk of 10 mothers who had SAM children which also had a significantly increased relative abundance of L. monocytogenes (0.34 (SD 0.35) vs 0.05 (SD 0.07) in controls, p<0.0001). The high genomic similarity between these strains and Malian breast milk strains from a previous study supports the hypothesis of endemic clone carriage in West Africa. Moreover, the in vitro growth inhibition of L. monocytogenes using breast milk samples was obtained from only 50% of the milk of mothers who had SAM children, in contrast to control samples which systematically inhibited the growth of L. monocytogenes with a higher inhibition diameter (15.7 mm (SD 2.3) in controls versus 3.5 mm (SD 4.6) in SAM, p = 0.0001). Lactobacillus and Streptococcus isolated from the breast milk of controls inhibit L. monocytogenes in a species-dependent manner.Conclusions/SignificanceOur study reveals a previously unsuspected carriage of L. monocytogenes in the breast milk of West African women, which is associated with SAM. The inhibitory effect of human selected lactic acid bacterial species against L. monocytogenes might provide new therapeutic and inexpensive options to prevent and treat this neglected public health issue. 相似文献
79.
Mamadou O. Traore Moussa D. Sarr Alioune Badji Yiriba Bissan Lamine Diawara Konimba Doumbia Soula F. Goita Lassana Konate Kalifa Mounkoro Amadou F. Seck Laurent Toe Seyni Toure Jan H. F. Remme 《PLoS neglected tropical diseases》2012,6(9)
Background
Mass treatment with ivermectin controls onchocerciasis as a public health problem, but it was not known if it could also interrupt transmission and eliminate the parasite in endemic foci in Africa where vectors are highly efficient. A longitudinal study was undertaken in three hyperendemic foci in Mali and Senegal with 15 to 17 years of annual or six-monthly ivermectin treatment in order to assess residual levels of infection and transmission, and test whether treatment could be safely stopped. This article reports the results of the final evaluations up to 5 years after the last treatment.Methodology/Principal Findings
Skin snip surveys were undertaken in 131 villages where 29,753 people were examined and 492,600 blackflies were analyzed for the presence of Onchocerca volvulus larva using a specific DNA probe. There was a declining trend in infection and transmission levels after the last treatment. In two sites the prevalence of microfilaria and vector infectivity rate were zero 3 to 4 years after the last treatment. In the third site, where infection levels were comparatively high before stopping treatment, there was also a consistent decline in infection and transmission to very low levels 3 to 5 years after stopping treatment. All infection and transmission indicators were below postulated thresholds for elimination.Conclusion/Significance
The study has established the proof of principle that onchocerciasis elimination with ivermectin treatment is feasible in at least some endemic foci in Africa. The study results have been instrumental for the current evolution from onchocerciasis control to elimination in Africa. 相似文献80.
Y. Sow A. Thiam B. Fall M. Coulibali A. Sarr B. Diao P. A. Fall A. K. Ndoye M. Ba B. A. Diagne 《Andrologie》2012,22(2):102-107