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21.
Hepatitis E is a rare human disease in Central Europe commonly imported from endemic regions. For autochthonous infections a zoonotic transmission from pigs, deer and wild boar is assumed. Using three different RT-PCR protocols, hepatitis E virus (HEV) RNA was detected in 10 out of 189 (5.3%) serum samples collected in 1995/1996 from wild boars in Germany. Sequence analysis indicates a close relationship with genotype 3 isolates of pigs and humans from the Netherlands and Japan. The results indicate that HEV is present in Germany since more than 10 years and that wild boar may function as a reservoir for HEV. 相似文献
22.
The effects of different planting densities (250,000, 500,000 and 750,000 plants ha−1) and cutting frequencies (45, 60 and 75 days) on the biomass production and chemical composition of Moringa oleifera was studied in a completely randomised split plot design with four blocks, in Managua, Nicaragua, located geographically
at 12°08′15′′ N and 86°09′36′′ E. The 75 day cutting frequency produced the highest fresh matter yield, 100.7 and 57.4 Mg ha−1 year−1, and dry matter (DM) yield, 24.7 and 10.4 Mg ha−1 year−1, during the first and second year, respectively. All planting densities produced the highest DM yield at 75 day cutting frequency.
In the first year, the density of 750,000 plants ha−1 produced the highest fresh matter yield, 88.0 Mg ha−1 and highest DM yield, 18.9 Mg ha−1, but in the second year the density of 500,000 plants ha−1 gave the highest yields, 46.2 Mg ha−1 and 8.1 Mg ha−1, respectively. During the first year, DM (22.8%), neutral detergent fibre (NDF) (30.8%) and ash (9.14%) contents were highest
and in vitro DM digestibility (IVDMD) (68.2%) was lowest in the longest cutting interval, while contents of crude protein (CP) (22.8%)
and acid detergent fibre (ADF) (22.8%) were not affected significantly by cutting frequency. In the second year, DM and CP
contents and IVDMD were not significantly affected by cutting frequency, whereas NDF, ADF and ash contents were lowest in
the 60 day cutting frequency. Planting density had no significant effect on chemical composition or IVDMD. These data suggest
that Moringa forage could be an interesting protein supplement for ruminants. 相似文献
23.
In many traditionally managed agroecosystems, populations of domesticated plants maintain high levels of genetic diversity. The threat of erosion of this diversity is a current conservation concern, motivating studies of how diversity can be maintained by in situ conservation measures. Precisely how the biological traits of plants and the cultural practices of farmers act on fundamental evolutionary forces - drift, migration, selection, and mutation - to create and maintain crop plant diversity has been little investigated in detail. We develop some elements of the framework required for studying such biocultural interactions, focusing on one component of management: farmers' decisions on what to plant, and the structure of germplasm exchange among farmers. We illustrate the approach with a study of Duupa farmers in northern Cameroon. Our results suggest that sorghum populations managed by the Duupa function like source-sink metapopulations. Fields of older farmers, larger and containing a greater number of varieties, act as sources, whereas fields of younger farmers act as sinks, becoming sources as their owners mature. In each field, seeds for sowing are selected from a small number of plants. The frequent exchange of germplasm among fields may counteract the genetic bottlenecks associated with the small number of genitors within each field. Identifying key processes and key individuals should facilitate the design of in situ conservation measures to maintain crop plant diversity against the threat of genetic erosion. 相似文献
24.
Dipta DEY Tanzila Ismail EMA Partha BISWAS Sharmin AKTAR Shoeba ISLAM Urmi Rahman RINIK Mahmudul FIROZ Shahlaa Zernaz AHMED Salauddin AL AZAD Ahsab RAHMAN Sadia AFRIN Rezwan Ahmed MAHEDI Md. Nasir Uddin BADAL 《农业科学与工程前沿(英文版)》2021,8(4):603
25.
Genetic and Phenotypic Diversity in the Graminaceous Cyst Nematode Complex, Inferred from PCR-RFLP of Ribosomal DNA and Morphometric Analysis 总被引：3，自引：0，他引：3
Roger Rivoal Sylvie Valette Sadia Bekal Jean-Pierre Gauthier Amor Yahyaoui 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(3):227-241
Graminaceous cyst nematodes form a group of eleven valid species including Heterodera avenae, Heterodera filipjevi and Heterodera latipons and constitute major pests to cereals. They are widely spread in circum-mediterranean areas where they are presumed to cause yield losses on bread and durum wheat. The objective was to document the diversity of these cereal cyst nematodes, in particular samples from Mediterranean regions, in comparison to species which develop on cultivated or wild grasses (H. arenaria, H. hordecalis, H. mani) and on rice or sugarcane (H. sacchari). Studies involved PCR-RFLP of ITS and morphometrics of the juvenile and cyst characters. UPGMA analysis of molecular data showed that the isolates segregated in two main clusters which seem to represent different evolutionary lineages. The H. avenae sensu lato cluster (I) contained H. arenaria, H. avenae, H. filipjevi and H. mani. The second cluster (II) contained isolates of H. hordecalis and H. latipons. Within H. avenae sensu lato, H. filipjevi was separated from the other related species with significant bootstrap value. The differentiation of H. arenaria, recognized for the first time based on molecular data, and H. mani with few restriction enzymes were the least significant. Intraspecific polymorphism allowed differentiation of isolates originating from Australia within H. avenae sensu stricto. The group H. hordecalis–H. latipons showed the greatest genetic variability between and within isolates. Two representatives of Heterodera sacchari, taxonomically included in the schachtiigrave group, were genetically as distant to this group as to the other graminaceous species belonging to either H. avenae sensu lato or H. hordecalis–H. latipons group. Results inferred from multivariate analysis applied on morphometrics of the cysts and juveniles showed agreement between genetic and phenotypic classifications. This study demonstrates the utility of combined molecular and classical methods to enhance our knowledge about the diversity within the complex of graminaceous cyst nematodes and to establish robust techniques to identify a wider set of nematode species. 相似文献
26.
Coir fiber reinforced polypropylene composite panel for automotive interior applications 总被引：1，自引：0，他引：1
Nadir Ayrilmis Songklod Jarusombuti Vallayuth Fueangvivat Piyawade Bauchongkol Robert H. White 《Fibers and Polymers》2011,12(7):919-926
In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite
panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were
mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and
the internal bond strength of the composites were negatively influenced by increasing coir fiber content. However, the flexural
strength, the tensile strength, and the hardness of the composites improved with increasing the coir fiber content up to 60
wt %. The flame retardancy of the composites improved with increasing coir fiber content. The results suggest that an optimal
composite panel formulation for automotive interior applications is a mixture of 60 wt % coir fiber, 37 wt % PP powder, and
3 wt % MAPP. 相似文献
27.
Kayani S Zia M Sarwar S Riaz-ur-Rehman Chaudhary MF 《Pakistan journal of biological sciences: PJBS》2008,11(6):950-952
With the objective to promote in vitro callus induction, leaf segments of Achyranthes aspera were inoculated on basal MS medium supplemented with 3.0% sucrose and 0.8% agar with different concentrations of 2,4-D alone and in combination with NAA, BAP, IAA, IBA and Zeatin. The explants were maintained in growth room at 25 +/- 1 degrees C and 16 h light cycle. The best callus induction was obtained with 2,4-D (1.0 and 2.0 mg L(-l)) in combination with NAA (0.5 mg L(-1)). Callus induction and good texture from leaf explant was also observed at 2,4-D with BAP. On these combinations morphologically, light green, soft, compact and non-embryogenic callus (Type III callus) was observed. While morphology of callus and callogenic response was poor at 2,4-D alone or in combination with other hormones at different concentrations. 相似文献
28.
不同沙棘籽提取物的抗氧化和抗菌活性研究 总被引：6，自引：0，他引：6
使用Soxhlet提取装置,用氯仿、乙酸乙酯、丙酮、甲醇4种不同溶剂对沙棘籽分别进行8小时萃取。粗提物被用来进行抗氧化和抗菌活性筛选。在离体模型(清除DPPH自由基和脂质体模型系统)中的粉末减少和抗氧化活性评价显示在各种提取物中使用甲醇作为萃取剂的提取物具有最高的抗氧化活性。甲醇提取物也具有最高的抗菌活性。最低抑制浓度(MIC)评价显示,在加入甲醇提取物对蜡状芽孢杆菌、凝结芽孢杆菌、枯草芽孢杆菌、单核细胞增生利斯特菌、小肠结肠炎耶尔森氏菌进行培养,MIC浓度分别为200,300,300,300,和350ppm。研究结果表明,沙棘种子应用于医药和食品储藏。 相似文献
29.
Rafiq Ahmad Mahmood-ul- Hassan Ghanan B. Akhtar Sadia Saeed Sabaz A. Khan Muhammad Kausar Nawaz Shah Nadeem Khan 《Plant Breeding》2020,139(5):988-995
Onion is one of the major vegetable crops in terms of production as well as consumption. In the current research, available onion genetic stock was evaluated to identify male-sterile lines and produce high-yielding F1 hybrids for future breeding programmes. A mitochondrial DNA-based marker was mapped and correlated with phenotypic traits to isolate male-sterile plants. Based on the floral and pollen structure, nine putative male-sterile lines were identified. On the other hand, for nuclear marker identification at Ms locus, two sets of primers were used, one for Ms dominant allele and another for sterile and maintainer plants. Results revealed that 70% of open pollinated varieties (OPVs) possess plants with sterile cytoplasm coupled with genetic sterility at Ms locus, called sterile “A” line. Approximately 20% of plants in some genotypes were identified with normal (N) cytoplasm having recessive fertility gene at Ms locus, called maintainer “B” line. Based on the present findings, “A”, “B” and “R” (restorer line), future F1 hybrid seed production systems in onion is discussed. 相似文献
30.
Variations in compression strength and surface roughness of heat-treated Turkish river red gum (Eucalyptus camaldulensis) wood 总被引：1，自引：0，他引：1
This article reports the effects of heat treatment on compression strength parallel to the grain, the surface roughness [average roughness (Ra)], and the air-dry den-sity of wood from the river red gum tree (Eucalyptus camaldulensis Dehn.) planted in Turkey. Eucalyptus wood was heat-treated at temperatures varying from 120° to 180°C for durations of 2–10 h. Samples cut from the heat-treated wood were tested for air-dry density, compression strength parallel to grain, and surface roughness properties. Roughness measurements by the stylus method were made in the direction perpendicular to the fiber. Based on the findings in this study, the results showed that density, compression strength, and surface roughness values decreased with increasing treatment temperature and treatment times. Eucalyptus wood could be utilized by using proper heat treatment techniques without any losses in strength values in areas where working, stability, and surface smoothness, such as in window frames, are important factors. 相似文献