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81.
Tatiana Fioravanti Filippo Bargnesi Andrea Splendiani Massimo Giovannotti Francesca Renzi Vincenzo Caputo Barucchi 《水产资源保护:海洋与淡水生态系统》2020,30(5):892-902
- The sand tiger shark (Carcharias taurus) is a coastal species distributed in temperate and sub‐tropical waters, classified as ‘Vulnerable’ at global level and ‘Critically endangered’ in eastern Australia, south‐western Atlantic Ocean, and Mediterranean Sea. Six populations (north‐western Atlantic, Brazil, South Africa, Japan, eastern Australia, and western Australia) with low genetic diversity and limited gene flow were identified worldwide, but genetic information for many other geographic areas are still missing. Specifically, this species is listed in several reports as part of the Mediterranean fauna, even if there has been a lack of catches and sightings in recent years in this basin. To clarify the origin of C. taurus individuals caught in the past in the Mediterranean Sea, historical samples were genetically analysed.
- Nine samples with certain Mediterranean origin were collected from different European museums. DNA was extracted and ~600 bp of the mitochondrial DNA control region were amplified using eight overlapping species‐specific primer pairs. Sequences obtained were aligned with all the haplotypes globally known so far.
- Genetic analysis revealed the misidentification of one museum specimen. Among the remaining Mediterranean historical samples, three different haplotypes were recovered. Two of them previously observed only in South Africa and one described in both South African and Brazilian populations.
- Results suggest a genetic relationship between Mediterranean sand tiger sharks and those from the western Indian Ocean. According to previous studies, we hypothesized that, during the Pleistocene, the cold Benguela upwelling barrier was temporarily reduced allowing the passage of C. taurus individuals from the Indian to Atlantic Ocean. After the restoration of this phylogeographic barrier some individuals were trapped in the Atlantic Ocean and probably migrated northward colonizing the western African coasts and the Mediterranean Sea.
82.
Disentangling effects of habitat diversity and area on orthopteran species with contrasting mobility
Loss of semi-natural grasslands and reduction of habitat diversity are considered major potential threats to arthropod diversity in agricultural landscapes. The main aim of this study was to investigate how area and habitat diversity, mediated by shrub encroachment after grassland abandonment, affect species richness of orthopterans in island-like grasslands, and how contrasting mobility might alter species richness response to both factors. We selected 35 isolated patches in landscapes dominated by arable land (durum wheat) in order to obtain two statistically uncorrelated gradients: (i) one in habitat area ranging from 0.2 to 55 ha and (ii) one in habitat diversity ranging from patches dominated by one habitat (either open grasslands or shrublands) to patches with a mosaic of different habitats. Habitat loss due to land-use conversion into arable fields was associated with a substantial loss of species with a positive species-area relationship (SAR), with sedentary species having a steeper and stronger SAR than mobile species. Halting habitat loss is, therefore, needed to avoid further species extinctions. Shrub encroachment, triggered by abandonment, presented a hump-shaped relationship with habitat diversity. An increase in habitat diversity enhanced species richness irrespective of patch area and mobility. Maintaining or enhancing habitat diversity, by cutting or burning small sectors and by reintroducing extensive sheep grazing into abandoned grassland, are suggested as complementary strategies to mitigate further decline of orthopteran diversity in the remnant patches. This would be equally important in both small and large patches. 相似文献
83.
围产奶牛饲养要点 总被引:1,自引:0,他引:1
AndreaMurphy 《乳业科学与技术》2002,25(1):44-50
在有效的饲养操作下,奶牛的产奶量、健康状况及繁殖性能可达到良好平衡。获得高的经济回报的关键在于上述三方面性能都能保持良好。围产期是奶牛在泌乳周期中进行泌乳和确保良好的健康、繁殖状况的一个关键契机。围产期指产犊前60天至产犊后60天。而围产期中最为关键的时间是产犊前21天至产犊后21天。围产期的饲喂及管理操作的正确性对于奶牛的干物质 相似文献
84.
意大利冷冻精液质量的官方监控 总被引:1,自引:0,他引:1
1991年1月15日,意大利政府公布了动物生产法,即法律30(legge30),全面介绍了动物生殖细胞生产中心应具备的条件、建立养殖场的要求和动物繁殖的规章制度。1994年1月13日,意大利农业部依据法律30发布了第172号部长令,详细说明了自然交配、人工授精和胚胎移植的规章制度。部长令规定,意大利任何冻精生产中心(简称中心)生产的冻精或从国外引入的冻精,必须至少取出精液生产批次10%的样品,进行官方检测。司拜伦谨尼研究所(简称研究所)是意大利农业部委托的唯一的执行机构,检测的最后结果是:比较研究所… 相似文献
85.
86.
Elena?Zini Franco?Biasioli Flavia?Gasperi Daniela?Mott Eugenio?Aprea Tilmann?D.?M?rk Andrea?Patocchi Cesare?Gessler Matteo?KomjancEmail author 《Euphytica》2005,145(3):269-279
The availability of genetic linkage maps enables the detection and analysis of QTLs contributing to quality traits of the
genotype. Proton Transfer Reaction Mass Spectrometry (PTR-MS), a relatively novel spectrometric technique, has been applied
to measure the headspace composition of the Volatile Organic Compounds (VOCs) emitted by apple fruit genotypes of the progeny
‘Fiesta’ × ‘Discovery’. Fruit samples were characterised by their PTR-MS spectra normalised to total area. QTL analysis for
all PTR-MS peaks was carried out and 10 genomic regions associated with the peaks at m/z = 28, 43, 57, 61, 103, 115 and 145 were identified (LOD > 2.5). We show that it is possible to find quantitative trait loci
(QTLs) related to PTR-MS characterisation of the headspace composition of single whole apple fruits indicating the presence
of a link between molecular characterisation and PTR-MS data. We provide tentative information on the metabolites related
to the detected QTLs based on available chemical information. A relation between apple skin colour and peaks related to carbonyl
compounds was established.
The two authors contributed equally to this work. 相似文献
87.
Nine populations of rye (Secale cereale L.; the cultivars ‘Kustro’, ‘Danko’ and ‘Carokurz’. a breeding population PA 14/75 and five Iranian primitive ryes) were tested with three or two pathotypes of powder)’ mildew (Erysiphe graminis DC. f. sp. secalis Marchal) to determine the frequencies of vertical resistances. Similarly, three populations of powder)’ mildew isolated from the above eultivars were tested with two rye pathodemes to estimate the frequencies of vertical virulences. Tests were carried out on leaf segments cultivated in vitro. To explain the pattern of the host-parasite interaction, a model with at least four resistance and virulence genes was required. In the rye populations the genotypes of most plants could be determined unambiguously whereas in the powdery mildew populations no unique classification of one-postule isolates was possible due to the limited number of rye differentials. Both the host and the pathogen populations were polymorphic for resistance and virulence, respectively. In all lye populations except PA 14/75 the resistance frequencies were low. In the mildew populations the virulence frequencies were high and complex races occurred rather frequently. The virulence frequencies were related to the resistance frequencies of the respective host population. Results were compared with mathematical host-parasite models accounting for gene-for-gene interaction and balancing natural selection. Observations agree well with theory. 相似文献
88.
Angioni A Barra A Russo MT Coroneo V Dessi S Cabras P 《Journal of agricultural and food chemistry》2003,51(10):3073-3078
The composition of the essential oil from ripe and unripe berries and leaves of Juniperus oxycedrus L. ssp. oxycedrus, Juniperus phoenicea ssp. turbinata and Juniperus communis ssp. communis was analyzed by GC-MS, and microbiological assays were carried out. Samples were collected in different localities (Sardinia, Italy) and hydro distilled. The yields ranged between 2.54% +/- 0.21 (v\w dried weight) and 0.04% +/- 0.00. A total of 36 components were identified. The major compounds in the essential oils were alpha-pinene, beta-pinene, delta-3-carene, sabinene, myrcene, beta-phellandrene, limonene, and D-germacrene. Both qualitative and quantitative differences between species and between different parts of the plant were observed. The essential oils and their major compounds were tested against Candida albicans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and the minimum inhibitory concentration and minimum bactericidal concentration were determined. The results obtained led to a nonsignificant inhibitory effect, although all the essential oils from Juniperus phoenicea ssp. turbinata and the essential oil from leaves of Juniperus oxycedrus ssp. oxycedrus exhibited rather good or weak activity against Candida albicans and Staphylococcus aureus. 相似文献
89.
Cocchi M Franchini G Manzini D Manfredini M Marchetti A Ulrici A 《Journal of agricultural and food chemistry》2004,52(13):4047-4056
A comparison of different digestion procedures has been carried out for the analysis of metal concentration in samples of vinegars and Aceto Balsamico Tradizionale of Modena (ABTM) coming from an unique barrel set. In particular, classical wet, dry ashing, and closed vessel microwave digestion procedure have been utilized and compared for each investigated species. In a few cases, direct metal determination on ABTM (without treatment procedure) is proposed as possible alternative to sample manipulation. Flame atomic absorption spectrometry was used for the quantification of iron and zinc, while graphite furnace atomic absorption spectrometry was used for all the other elements (i.e., chromium, manganese, cobalt, nickel, copper, cadmium, and lead). The comparison among the different sample treatments was carried out by the use of statistical and chemometric tools. In particular, principal component analysis and ANOVA approaches were used to discriminate between the diverse analytical methods. Furthermore, for all the dissolving techniques, the analytical metal recovery was always evaluated by the application of the recovery function on the same sample matrix. In general, the recoveries were fairly good, ranging from 90 to 103%, except for Cd and Pb with dry ashing, which showed recovery values close to 55% and 67%, respectively. As regards the metals concentration of the investigated samples, the experimental data reveal for some species the presence of concentration slightly over the legal limit fixed for wine and wine vinegar. 相似文献
90.
Tancredi Caruso Francesca Borghini Andrea Colacevich 《Soil biology & biochemistry》2007,39(11):2949-2956
Soil fauna in the extreme conditions of Antarctica consists of a few microinvertebrate species patchily distributed at different spatial scales. Populations of the prostigmatic mite Stereotydeus belli and the collembolan Gressittacantha terranova from northern Victoria Land (Antarctica) were used as models to study the effect of soil properties on microarthropod distributions. In agreement with the general assumption that the development and distribution of life in these ecosystems is mainly controlled by abiotic factors, we found that the probability of occurrence of S. belli depends on soil moisture and texture and on the sampling period (which affects the general availability of water); surprisingly, none of the analysed variables were significantly related to the G. terranova distribution. Based on our results and literature data, we propose a theoretical model that introduces biotic interactions among the major factors driving the local distribution of collembolans in Antarctic terrestrial ecosystems. 相似文献