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71.
Impacts of a mineral lick‐centred land use system on woody vegetation cover in an East African Savannah
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Habtamu Teka I.C. Madakadze Abubeker Hassen Ayana Angassa Mohammed Mussa 《African Journal of Ecology》2018,56(3):591-600
Evaluation of woody vegetation changes with distance from a salt crater was conducted in the semi‐arid rangelands of southern Ethiopia. Data on live woody plants were collected over three seasons at 0, 1, 4, 6, 9 and 12 km from the salt crater. The density and diversity of woody plants differed significantly (p < .01) along the distance gradient. Six woody plant families were identified of which Fabaceae and Burseraceae were the dominant families. Acacia drepanolobium, Acacia nilotica, Commiphora africana and Acacia mellifera were among the severely encroaching woody species. There were high proportions of seedlings and saplings recorded closer to the salt crater showing a vigorous recruitment by woody plants. Woody plant encroachment along the 12‐km transect ranged from a low to severe encroachment, which could be translated into poor rangeland condition. Changes in soil characteristics increased grazing pressure and sedentary settlement around the salt crater, and the breakdown of traditional institutions seems to be major contributing factors to these vegetation changes. We suggest that severely encroached areas could be improved through a combination of methods such as bush clearing, prescribed fire, browsing animals and proper grazing management. 相似文献
72.
Population structure from NOS genes correlates with geographical differences in coronary incidence across Europe
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73.
A Hassen N Filali N Jedidi N Kallali A Beji A Mougou 《Archives de l'Institut Pasteur de Tunis》1992,69(3-4):307-325
The present study aim was to valorize the treated waste water as source of fertilizers for vegetables seed production and to assess the eventual bacteriological contamination risks of soil, plant and phreatic ground water table. The bacteriological analysis of drained water did not reveal any fecal coliforms vertical migration in depth and a low fecal contamination (thermotolerant coliforms) is limited to the levels of superficial horizons. The seed produced by using waste water showed a slightly fecal contamination which disappeared following treatment with a (5% chloride solution. The treated waste water improve the onion seeds production per hectare in spite of the increases of the phytopathogenic hazards. 相似文献
74.
Ronan Le HyaricCaroline Chardin Hassen BenbelkacemJulien Bollon Rémy BayardRenaud Escudié Pierre Buffière 《Bioresource technology》2011,102(2):822-827
The objective of this study was to evaluate the influence of substrate concentration and moisture content on the specific methanogenic activity (SMA) of a fresh dry mesophilic digestate from a municipal solid waste digester plant. For this purpose, SMA tests were performed under mesophilic conditions into glass bottles of 500 mL volume used as batch reactors, during a period of 20-25 days. Propionate was used as substrate at concentrations ranging from 1 to 10 gCOD/kg. Four moisture contents were studied: 65%, 75%, 80% and 82%. Experimental results showed that propionate concentration and moisture content strongly influenced the SMA. The highest SMA was observed at a substrate concentration of 10 gCOD/kg (11.3 mgCOD gVS−1 d−1 for the second dose of propionate) and at a moisture content of 82% (7.8 mgCOD gVS−1 d−1 for the second dose of propionate, at a concentration of 5 gCOD/kg). SMA was found to decrease linearly when decreasing the moisture content. 相似文献
75.
Arij Mechergui Wafa Achour Assia Ben Hassen 《World journal of microbiology & biotechnology》2014,30(8):2181-2188
We aimed to compare accuracy of genus and species level identification of Neisseria spp. using biochemical testing and 16S rRNA sequence analysis. These methods were evaluated using 85 Neisseria spp. clinical isolates initially identified to the genus level by conventional biochemical tests and API NH system (Bio-Mérieux®). In 34 % (29/85), more than one possibility was given by 16S rRNA sequence analysis. In 6 % (5/85), one of the possibilities offered by 16S rRNA gene sequencing, agreed with the result given by biochemical testing. In 4 % (3/85), the same species was given by both methods. 16S rRNA gene sequencing results did not correlate well with biochemical tests. 相似文献
76.
Ghada Ben Salah Ikhlas Hadj Salem Abderrahmen Masmoudi Fakhri Kallabi Hamida Turki Faiza Fakhfakh Hamadi Ayadi Hassen Kamoun 《Molecular biology reports》2014,41(11):7373-7380
The Bloom syndrome (BS) is an autosomic recessive disorder comprising a wide range of abnormalities, including stunted growth, immunodeficiency, sun sensitivity and increased frequency of various types of cancer. Bloom syndrome cells display a high level of genetic instability, including a 10-fold increase in the sister chromatid exchanges (SCE) level. Bloom syndrome arises through mutations in both alleles of the BLM gene, which was identified as a member of the RecQ helicase family. In this study, we screened a Tunisian family with three BS patients. Cytogenetic analysis showed several chromosomal aberrations, and an approximately 14-fold elevated SCE frequency in BS cells. A significant increase in SCE frequency was observed in some family members but not reaching the BS patients values, leading to suggest that this could be due to the heterozygous profile. Microsatellite genotyping using four fluorescent dye-labeled microsatellite markers revealed evidence of linkage to BLM locus and the healthy members, sharing higher SCE frequency, showed heterozygous haplotypes as expected. Additionally, the direct BLM gene sequencing identified a novel homozygous frameshift mutation c.3617–3619delAA (p.K1207fsX9) in BS patients and a heterozygous BLM mutation in the family members with higher SCE frequency. Our findings suggest that this latter mutation likely leads to a reduced BLM activity explaining the homologous recombination repair defect and, therefore, the increase in SCE. Based on the present data, the screening of this mutation could contribute to the rapid diagnosis of BS. The genetic confirmation of the mutation in BLM gene provides crucial information for genetic counseling and prenatal diagnosis. 相似文献
77.
Panday N Benz J Blum-Kaelin D Bourgeaux V Dehmlow H Hartman P Kuhn B Ratni H Warot X Wright MB 《Bioorganic & medicinal chemistry letters》2006,16(19):5231-5237
A series of branched and unbranched anilinohexafluoroisopropanols related to the known sulfonamide T0901317 were prepared and evaluated as activators/modulators of both LXRalpha and LXRbeta. A structure-activity relationship was established and compounds with high potency on both the receptors were identified. Many compounds showed a tendency toward selectivity for LXRbeta versus LXRalpha. Several analogues were evaluated for effects on plasma lipoprotein levels in mice. A few of these significantly raised HDL-cholesterol levels in plasma but showed markedly different effects on liver triglyceride content, suggesting that this series may yield candidates with improved efficacy/safety profiles compared to existing molecules. 相似文献
78.
Pearson MS Saad RO Dintinger T Amri H Mathé-Allainmat M Lebreton J 《Bioorganic & medicinal chemistry letters》2006,16(12):3262-3267
Adenophorine and its 5-deoxy analogue have been identified as natural iminosugars with efficient glycosidase inhibitory effects. The syntheses and biological evaluation of two new series of 5-deoxyadenophorine analogues in their racemic form are reported. The compounds 12e and 13d bearing a C11 and C7 alkyl chain, respectively, were found to be potent inhibitors of the beta-glucosidase from almond with Ki near to 60 microM. The compounds 13a,d which possess a 3,4-cis stereochemistry were efficient on glucosidases but also on the beta-galactosidase, what was not observed with the 3,4-trans series 12. 相似文献
79.
Ghada Ben Salah Hassen Kamoun Ahmed Rebai Rafika Hajji Mohamed-Elaarbi Masmoudi Hamadi Ayadi 《人类与生态风险评估》2013,19(4):1089-1101
Gasoline constitutes a mixture of chemicals that contain well-known genotoxicants. Thus, chronic occupational exposure to gasoline may be considered to possess genotoxic risk. In this study, the frequencies of total chromosomal aberrations (TCA), aberrant cells (Ab.c.), sister chromatid exchanges (SCE), high-frequency cells (HFC), and high-frequency cell individual (HFI) were investigated in peripheral blood lymphocytes from 17 gasoline-exposed workers (10 smokers and 7 non-smokers) and 22 unexposed reference subjects (12 smokers and 10 non-smokers). The exposed subjects were gasoline truck loaders at a gasoline company from Tunis City, north of Tunisia. The results indicate multiple CA, such as dicentrics (DIC), chromatid breaks (SB), and chromosome breaks (DB). A significant difference was observed in TCA and Ab.c. frequencies between exposed and unexposed groups (p < 0.01). A significant difference was found in frequencies of SCE (p < 0.01) and HFI (p < 0.05) between exposed and unexposed groups. SCE and TCA frequencies of smokers were found to be significantly higher than those of non-smokers in both groups. There was an interaction between gasoline exposure and smoking habit for TCA (p = 0.020), but not for SCE. Our findings indicate that gasoline truck loaders were under risk of significant cytogenetic damage that was enhanced by their smoking habit. 相似文献
80.
We have synthesized the fully unsymmetrical [(6-bromo 2-pyridylmethyl) (6-fluoro 2-pyridylmethyl) (2-pyridylmethyl)] amine tripod FBrTPA. The synthesis involves preparation of the already known [(6-bromo 2-pyridylmethyl) (2-pyridylmethyl)] amine BrDPA, which is obtained either by classical condensation of α-substituted pyridine carboxaldehyde with aminomethyl pyridine, or by a pathway involving the protection/deprotection sequence of this primary amine. This second way is useful for syntheses of monosubstituted DPAs in the cases where α-substituted pyridine carboxaldehydes are unavailable. The crystal structure of the FeCl2 complex shows that the ligand binds in a κ4-N fashion, with however relatively long ligand-to-metal distances. The spectroscopic and electrochemical studies support decoordination of the bromopyridyl substituent in solution, with κ3-N coordination mode of the tripod within a complex displaying a trigonal bipyramidal geometry at the metal centre. This complex reacts easily with dry oxygen to yield an unsymmetrical μ-oxo diferric complex, the structure of which is also reported. 相似文献