Isolation and characterisation of local strains of Chlamydophila abortus (Chlamydia psittaci serotype 1) from Tunisia

Chlamydiosis is one of the major diseases that can lead to abortion in ewes. Since 1997, in 5 regions of Tunisia, Chlamydia-related abortions have been reported in 15 sheep and goat flocks. One hundred and sixty-six sera and 50 vaginal swab samples were collected from adult ewes. Chlamydial antigens were detected in 29 (58%) of the vaginal swabs using Enzyme Linked Immunosorbent Assay (ELISA) while 9 (18%) were positive by cell culture. Five strains were recovered from 4 different sheep flocks. Monoclonal antibody profiles and restriction fragment length polymorphism (RFLP) analysis of the 16S-23S rRNA spacer region showed that these isolates were C. abortus. Using amplified fragment length polymorphism (AFLP), these Tunisian strains were shown to exhibit the same pattern as strains isolated in France.     

中坝村退耕还林效益分析

笔者通过对秭归县茅坪镇中坝村退耕还林的现场详细调查,主要是水土保持经济林的单位面积效益进行评价,并使之与退耕还林前的农业生产效益相比较,阐明退耕还林的经济可行性和采取合理的相应措施。     

高铜日粮及补硒对瘦肉型生长肥育猪生长性能及组织结构的影响

选用35日龄杜施杂1代断奶仔猪40头,随机分成4组进行高铜及补硒试验.结果表明,Cu 125 ppm+Se 0.3 ppm(Ⅱ组)效果最佳,日增重比 Cu 4.36 ppm+Se 0.3 ppm(Ⅰ组)约提高15.9%(P<0.05);全期耗料较Ⅰ组下降12.6%.Cu 250 ppm+Se 0.3 ppm(Ⅲ组)与Ⅰ组的日增重差异不显著(P>0.05),耗料较Ⅰ组下降8.0%.但Ⅱ组与Ⅲ组日增重差异不显著(P>0.05).补 Cu250 ppm 不加 Se(Ⅳ组)与Ⅲ组相比,日增重约减少27.2%(P<0.01),耗料则较Ⅲ组高23.7%.屠体组织切片观察表明,添加高剂量铜(125或250 ppm)对机体组织均不产生病变,但各组的骨骼肌纤维粗细与十二指肠杯状细胞大小有明显的不同,均为Ⅱ>Ⅲ>Ⅰ>Ⅳ.     

Changes in chemical composition of Phoenix canariensis Hort. Ex Chabaud palm seed oil during the ripening process

The aim of this investigation is to compare the physicochemical properties and chemical composition of Phoenix canariensis seed oil at different stages of seed date ripening. It was demonstrated that the saponification number of the oil increases during the maturation from 179.24 to 191.28 (mg KOH/g of oil), whereas the seed oil yield, the iodine number, the p-anisidine value, the peroxide value, the acidity and the unsaponifiable matter decrease from 14.73% to 10.36%, from 89.37 to 76.66 (g/100 g of oil), from 5.51 to 3.67, from 17.66 to 3.62 (mequiv. O₂/kg of oil), from 1.49% to 0.59% and from 2.72% to 1.77%, respectively. The tocol content increases as the maturity advanced. The percentages of sterols show continuous changes during ripening. The saturated fatty acid content increases throughout the ripening process. The oleic fatty acid content decreases during the seeds maturation, but increases at the end, whereas linoleic acid content initially shows an increase, and then a decrease. The total phosphorus content decreases during the period of ripening. The three samples of the seed oil show a high kinetic stability during the heating and cooling, as characterised by the differential scanning calorimetry (DSC). The DSC curves reveal an increase in the melting point from −7.73 °C to 3.71 °C but the melting enthalpy remains the same, 62.06 J/g, during the ripening of the dates.     

Cultivar-based fruit size in olive depends on different tissue and cellular processes throughout growth

In drupe fruits, in addition to fruit size, the proportions of mesocarp and endocarp tissues are critical objectives for fruit quality, crop production and management. The olive fruit is a typical drupe, with cultivars which show a wide range in both fruit size and the proportions of mesocarp and endocarp. Characterizing the roles of tissue and cellular processes in producing genetically based fruit size variability is necessary for crop improvement, as well as deepening our understanding of fruit developmental physiology. This study used microscope image analysis to evaluate cell number and size, the growth of mesocarp and endocarp tissues, and their developmental timing in producing fruit size among six olive cultivars with a large range of fruit size. We found that cultivar mesocarp and endocarp size increased linearly with fruit size, with larger sizes favoring an increasingly greater mesocarp/endocarp ratio. Within the mesocarp, cultivar-based fruit size related directly to cell number and was established soon after bloom by cell division rate. In spite of different cell division rates, all cultivars showed similar timing of cell division activity, with the majority of cells produced in the two months after bloom but, surprisingly, a substantial number of cells formed during the following 6 months. Cell expansion was high throughout fruit growth and an important factor in achieving final fruit size, but cell size did not differ among cultivars at any time. We can conclude that fruit size differences among olive cultivars are due at the tissue level to both mesocarp and endocarp sizes and at the cellular level to cell division throughout fruit growth. Furthermore, since cell size is consistent among cultivars in spite of variable cell division, it is likely that cultivar differences in cell expansion accompany those in cell division.     

Activin‐A receptor expression patterns in prepubertal goat oocytes and derived embryos

This study examines the presence of activin IIA and IIB receptors (ActR‐IIA and ActR‐IIB) by Western blotting and immunocytochemistry in immature and IVM‐oocytes, 2 to 8‐cells embryos and blastocysts from prepubertal goats. Western blotting revealed that activin receptors are synthesized during oocyte maturation and embryo development. In the immunocytochemistry experiments, no immunostaining for either receptor was detected in oocytes while both receptors were immunolabelled in all the cells of cleaved embryos. In blastocysts, while ActR‐IIA expression appeared evenly distributed in the two cell lineages, inner cell mass and trophectoderm, the ActR‐IIB immunosignal was restricted mainly to the inner cell mass. Our findings reveal the presence of activin type II receptors (ActR‐IIA and ActR‐IIB) in in vitro matured prepubertal goat oocytes and blastocyst‐stage embryos. The expression of these receptors could be a key factor in understanding differences between competent and incompetent oocytes.     

Olive mill wastewater effects on the microbial communities as studied in the field of olive trees by analysis of fatty acid signatures

The aim of this work was to study the effects of spreading olive mill wastewater (OMW) on the soil surface of an olive grove on the soil microbial communities. Analyses of ester-linked fatty acid methyl esters (EL-FAME) were used to assess variations in the soil microbial community structure following land spreading of OMW. Our data provide evidence that agronomic application of OMW has important effects on soil microbial community. Bacteria were relatively more reduced by these treatments than fungi and actinomycetes as revealed by an increased index of fungal/bacterial FAME and actinomycetes/bacterial FAME. Specific FAME markers indicated a significant reduction in the Gram-positive bacteria. However, the relative proportion of the Gram-negative bacteria was not significantly different after agronomic application of OMW. The ratios of cyclopropyl/monoenoic precursors decreased and the total monounsaturated/total saturated fatty acids increased in the OMW amended soils, suggesting that the microbes inhabiting the control soil are more carbon limited than the OMW amended soils. The changes in the FAME pattern of the soil organisms possibly were related (i) to an altered substrate quantity, that is the availability of substrates after the treatments, (ii) the complex nature of OMW which also contains high molecular-mass recalcitrant polyphenols.     

Characteristics, composition and thermal stability of Acacia senegal (L.) Willd. seed oil

The chemical composition, main physicochemical properties and thermal stability of oil extracted from Acacia senegal seeds were evaluated. The oil, moisture and the ash contents of the seeds were 9.80%, 6.92% and 3.82%, respectively. Physicochemical properties of the oil were iodine value, 106.56 g/100 g of oil; saponification value, 190.23 mg KOH/g of oil; refractive index (25 °C), 1.471; unsaponifiable matter, 0.93%; acidity, 6.41% and peroxide value, 5.43 meq. O₂/kg of oil. The main fatty acids in the oil were oleic acid (43.62%) followed by linoleic acid (30.66%) and palmitic acid (11.04%). The triacylglycerols (TAGs) with equivalent carbon number ECN 44 (34.90%) were dominant, followed by TAGs ECN 46 (28.19%), TAGs ECN 42 (16.48%) and TAGs ECN 48 (11.23%). The thermal stability analysed in a normal oxidizing atmosphere showed that the oil decomposition began at 268.6 °C and ended at 618.5 °C, with two stages of decomposition at 401.5 °C and 576.3 °C. According to these results, A. senegal seed oil has physicochemical properties, fatty acids composition and thermal characteristics that may become interesting for specific applications in several segments of food and non-food industries.     

不同光质条件下马铃薯光响应曲线拟合模型的比较

为了研究不同光质处理下马铃薯的光合作用能力、光响应曲线,以及数据拟合模型的适用性,通过盆栽试验,利用蓝光(B)和红光(R)光源,设置B、B∶R=1∶3(B1R3)、B∶R=1∶5(B1R5)、B∶R=1∶7(B1R7)和R共5种不同的光质组合,测定马铃薯的光合色素、光合作用强度和光响应曲线,并用指数模型、直角双曲模型、非直角双曲模型、叶子飘模型和指数修正模型拟合光响应曲线,计算不同光质处理下的马铃薯光合参数。结果表明:B1R7处理下的光合色素含量和光合作用能力在5种处理中最高;叶子飘模型和指数修正模型的拟合效果整体较好,尤其是对P_nmax、LSP和R_d的拟合,指数模型、直角双曲模型和非直角双曲模型拟合效果较差;B1R7处理下马铃薯的光补偿点、光饱和点和最大净光合速率在5种光质处理中最高。综上,B1R7的光质组合可以增强马铃薯的光合作用,叶子飘模型和指数修正模型比较适合马铃薯光响应曲线的拟合。