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81.
【目的】在前期筛选获得对草地贪夜蛾高效致病真菌球孢白僵菌(Beauveria bassiana)菌株GZSL-1和玫烟色虫草(Cordyceps fumosorosea)菌株IFCF01的基础上,进一步明确2株菌株在草地贪夜蛾体表的侵染模式,为阐明菌株致病机理,提高昆虫病原真菌对草地贪夜蛾的防效提供理论依据。【方法】利用扫描电镜观察草地贪夜蛾2龄幼虫分别接种菌株GZSL-1和IFCF01(孢子悬浮液浓度为1.0×107孢子/mL)后分生孢子在幼虫体表附着、萌发、穿透和增殖的过程。【结果】菌株GZSL-1和IFCF01萌发后均可形成附着胞,草地贪夜蛾幼虫体表结构对2株菌株分生孢子萌发、附着和穿透芽管长度有不同程度的影响。2株菌株在各结构区均有较高的萌发率(> 90.00%)和附着胞率(> 80.00%),在平缓结构区比瘤状突起结构区观察到更短的穿透芽管。在各结构区,菌株GZSL-1形成的穿透芽管长度均短于菌株IF-CF01相应的芽管长度,在平缓结构区,菌株GZSL-1的穿透芽管长度显著短于菌株IFCF01(P<0.05)。菌株GZSL-1和IFCF01分生孢子接种后分别在16和8 h内萌发,在24和32 h内普遍出现穿透结构穿透草地贪夜蛾幼虫体壁。2株菌株的初级和次级分生孢子分别在接种后72和96 h内出现。【结论】扫描电镜观察证实球孢白僵菌菌株GZSL-1和玫烟色虫草菌株IFCF01对草地贪夜蛾具有高致病性,揭示了病原真菌分生孢子在草地贪夜蛾虫体上的侵染过程,结果为后续2株菌株的改良及田间应用打下理论基础。 相似文献
82.
Hasan B Faruque R Drobni M Waldenström J Sadique A Ahmed KU Islam Z Parvez MB Olsen B Alam M 《Avian diseases》2011,55(4):689-692
Antibiotic resistance in avian bacterial pathogens is a common problem in the Bangladesh poultry industry. The aim of the present study was to provide information on the present status of antibiotic resistance patterns in avian pathogenic Escherichia coli in Bangladesh. Of 279 dead or sick poultry of different ages, 101 pathogenic E coli strains isolated from broilers and layer hens with colibacillosis infections were screened to determine phenotypic expression of antimicrobial resistance against 13 antibiotics used in both veterinary and human medicine in Bangladesh. Of 101 pathogenic E. coli isolates, more than 55% were resistant to at least one or more of the tested compounds, and 36.6% of the isolates showed multiple-drug-resistant phenotypes. The most common resistances observed were against tetracycline (45.5%), trimethoprim-sulphamethoxazole (26.7%), nalidixic acid (25.7%), ampicillin (25.7%), and streptomycin (20.8%). Resistance to ciprofloxacin (12.9%), chlormaphenicol (8.9%), nitrofurantoin (2%), and gentamicin (2%) was also observed, and none of the isolates were resistant to tigecycline as well as extended spectrum beta-lactamase (ESBL) producers. One isolate was resistant to cefuroxime (1%), cefadroxil (1%), and mecillinam (1%) but was not an ESBL producer. Resistance rates, although significant in Bangladeshi isolates, were found to be lower than those reported for avian isolates from the Republic of Korea and clinical, avian, and environmental isolates from Bangladesh. The high level of antibiotic resistance in avian pathogens from Bangladesh is worrisome and indicates that widespread use of antibiotics as feed additives for growth promotion and disease prevention could have negative implications for human and animal health and the environment. 相似文献
83.
Ansar Mahmood Dr.Asma Hassan Iram Maqsood Tang Li-jie Syed Mohsin Bukhari Khalil-Ur-Rehman and Shahla Andleeb 《东北农业大学学报(英文版)》2014,21(1):45-51
An experiment was carried out to assess the phosphorus status of free grazing goats at Faisalabad,Pakistan.Samples were collected fortnightly during summer and winter seasons of 2010 from soil and plants.The highest(118±0.54 mg·kg-1)levels of feces phosphorus were recorded in lactating goats during winter and(9.87±0.99 mg·kg-1)in urine of male during winter.Similarly maximum(71.0±0.88 mg·kg-1)phosphorus concentration was observed in the plasma of lactating animals.Milk contained(31.0±0.36)mg·L-1 in winter while during the months of summer the highest values recorded in forages,soils,canal and tube well waters were(755±1.98)mg·kg-1,(785±4.98)mg·kg-1,(0.97±8.78)mg·L-1 and(4.12±0.55)mg·L-1,respectively.It was revealed from the current results that fecal matter,forage,milk,tube well and canal water contained lower amounts of P,while P levels in blood plasma was found within the critical limits.Therefore,phosphorus supplementations were required in the area under experimentation to meet the requirements of the animals for their normal growth. 相似文献
84.
Effect of dietary prebiotic inulin on histology,immuno‐haematological and biochemical parameters of Asian seabass (Lates calcarifer) 下载免费PDF全文
Sajjad Syed Raffic Ali Kondusamy Ambasankar Peter Ezhil Praveena Sambasivam Nandakumar Mohamed Saiyad Musthafa 《Aquaculture Research》2018,49(8):2732-2740
The present study was carried out to investigate the effect of supplementation of inulin on histology, immuno‐haematological and biochemical parameters of Asian seabass (Lates calcarifer) fingerlings with an initial average body weight of 7.14 ± 0.05 g. Inulin was supplemented at four different concentrations (control) 0, 5, 10, 15, and 20 g/kg in the L. calcarifer diet containing 400 g/kg protein and 90 g/kg lipid. At the end of the 60 days feeding trial, the absorptive surface area of the intestine and glycogen deposition in liver were increased in fish fed inulin supplemented diets. The immune parameters lysozyme, alternative complement pathway, superoxide dismutase and nitroblue tetrazolium assay showed significant (p < 0.05) difference between control and treatment groups. Haematological parameters showed that red blood cells, white blood cells, haemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration levels increased significantly (p < 0.05) in the fish fed with inulin supplemented diets. The analysis of biochemical parameters revealed that glucose, urea, cholesterol, triglyceride, aspartate aminotransferase, alkaline phosphatase, alanine aminotransferase, and lactate dehydrogenase showed significant differences (p < 0.05) between control and treatments groups. No significant difference (p > 0.05) was observed for total protein among different treatments. The results of the study revealed that 15–20 g/kg inulin supplementation has a beneficial effect in the histology, immuno‐haematological, and biochemical parameters in L. calcarifer juveniles. 相似文献
85.
Jose A. Cristancho Syed R. Syed Omar Mohamed Y. Rafii 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(6):487-498
Abstract Soil acidity is one of the main factors that limit profitable and sustained agricultural production. Oil palm (Elaeis guineensis Jacq.) is mainly planted in acidic soils. In the last years, there has been a stagnated yield and increases in disease incidence and severity worldwide that could be attributed in some extent to soil acidity. This study was conducted to determine the effects of soil acidity alleviation on oil palm seedlings. The effects of ground magnesium limestone or dolomite and magnesium carbonate (0, 1.1, 2.2, 3.3 and 4.4 t ha?1) applied to an Ultisol dominated by kaolinite (pH in water 4.4) were evaluated on selected morphological, physiological and nutritional characteristics of hybrid (Deli dura × AVROS pisifera) and clonal (clone 366) oil palm progenies under nursery conditions for 8 months. Increasing rates of ground magnesium limestone and magnesium carbonate showed a significant effect on improving soil pH and lowering exchangeable aluminium. The hybrid oil palm showed significant either linear or quadratic trends for most of the parameters evaluated, indicating that the best responses for morphological and physiological traits were achieved from 2.5 to 4.23 t ha?1 with ground magnesium limestone and 2.87 to 3.45 t ha?1 with magnesium carbonate. Positive effects of increasing rates of ground magnesium limestone and magnesium carbonate were observed on nitrogen and magnesium uptake. Aluminium concentration in the third frond decreased significantly with increasing ground magnesium limestone rate. A significant reduction of manganese uptake was also observed with increasing rates of both ameliorants. The clonal oil palm progeny exhibited a better performance on un-amended treatment. This may be explained by the significant higher root growth of this progeny. Soil acidity alleviation improved the oil palm seedling growth. These results are important for the oil palm industry and could be applied in the nursery stage as well as extended to the immature stage. 相似文献
86.
Sairah Syed Zammurad Iqbal Ahmed Muhammad Imran Al-Haq Ashiq Mohammad Yoshiharu Fujii 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(6):511-517
Tamarindus indica L. is well known for its acidic nature and allelopathic potential, but to date, little is known about its organic acids playing their role as allelochemicals. Hence, in the present study, identification, quantification, and contribution of organic acids present in its leaf extract were conducted using the principle of bioassay-guided procedure. High pressure liquid chromatography identified four organic acids, viz. citric, malic, oxalic, and tartaric acids, in its leaf aqueous extract with the predominance of oxalic acid (7.5 g kg?1 leaves fresh weight) followed by tartaric acid (7.3 g kg?1). The allelopathic activity of identified acids and aqueous extract was evaluated on lettuce seedlings growth based on the specific activity (EC50). The crude extract reduced radicle growth more adversely than hypocotyl at the concentration of 2.5 g L?1 (EC50). It hindered the normal physiological growth process through weak and curly seedlings, and necrosis of their tips. Among the identified acids, oxalic acid had the highest specific activity (40 mg L?1) and citric acid had the lowest (>1000 mg L?1). As a consequence of its high contents, the total activity, a function of specific activity and concentration, of oxalic acid (188) was found higher followed by tartaric acid (146). The contribution of both acids influencing the specific activity of the crude extract was then turned out to be 74%. To the best of our knowledge, this is the first report identifying the oxalic and tartaric acids as growth inhibitors in tamarind leaves and quantifying their contribution in its allelopathic expression. Based on the total activity, the results suggested that oxalic and tartaric acids are the major allelochemicals in tamarind leaves. The allelopathic potential of these acids might promote the development of natural herbicides as an alternative to the synthetic ones in a most sustainable manner. 相似文献
87.
Levels of genetic variation using 6 enzyme systems for a total of 11 interpretable loci were examined in chickpea (Cicer arietinum) originating from 9locations in Bangladesh. The measurement of genetic variation at enzyme loci was carried out on the seed
embryo, on the early leaves of seedlings and on the mature leaves at the vegetative stage. A total of 592individuals, including
240 seeds, 200 seedlings and152 mature leaves were investigated. Using electrophoretic data, chickpea was found to express
higher percentages of polymorphic loci at the seed stage (36–64%) than at seedling (22–56%) or the vegetative stage (11–44%).
The proportion of mean number of alleles and the average mean observed heterozygosity also were higher at the seed stage when
compared to the seedling and vegetative stages. Unique alleles were absent, and only differences infrequencies could be noticed.
Positive values of the fixation index were noted for pgm-1 and 6pg-1 for all stages and in both mnr loci for the seed embryo's.
A trend towards lower genetic distances of all possible pairs of populations could be observed when comparing those of seed
embryo's with seedlings or mature leaves. This trend was even more pronounced when pooling the data of 9 populations into
their 3regions. Slight differences in genetic distances caused a separative clustering of population 3 at seed embryo, of
population 2 at seedling and of population5 at vegetative stages. It is suggested that careful examination of enzyme polymorphisms
at different developmental stages is a prerequisite before drawing conclusions on the genetic distance between germplasm collections
from different origins since small differences in the data entry for clustering results in ties that may affect tree topologies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
88.
L. P. Kiær F. Felber A. Flavell R. Guadagnuolo D. Guiatti T. P. Hauser A. M. Olivieri I. Scotti N. Syed M. Vischi C. van de Wiel R. B. Jørgensen 《Genetic Resources and Crop Evolution》2009,56(3):405-419
Spontaneous gene flow between wild and cultivated chicory, Cichorium intybus L., may have implications for the genetic structure and evolution of populations and varieties. One aspect of this crop-wild
gene flow is the dispersal of transgenes from genetically modified varieties, e.g. gene flow from GM chicory to natural chicory
could have unwanted consequences. With the purpose to identify and quantify crop-wild gene flow in chicory, we analysed introgression
in 19 wild chicory populations and 16 accessions of chicory varieties and landraces distributed across Northern, Central and
Mediterranean Europe. The analysis used 281 AFLP markers and 75 SSAP markers giving a total of 356 polymorphic markers. Results
from model based assignments with the program STRUCTURE indicated many incidents of recent gene flow. Gene flow was observed
both between cultivars and wild populations, between landraces and wild populations, between different wild populations as
well as between cultivars. Population structure visualized by distance-based clustering showed a North–South geographical
structuring of the wild populations, and a general grouping of the cultivars corresponding to known origin. The results indicated,
however, that the structuring between the two groups of wild and cultivated types was weak. As crop and wild recipients are
genetically close and genes are transferred between the two types rather frequently, focus on mitigating crop-wild gene flow
should be increased, before transgenic varieties are cultivated openly. 相似文献
89.
Glenn GM Klamczynski AK Holtman KM Shey J Chiou BS Berrios J Wood D Orts WJ Imam SH 《Journal of agricultural and food chemistry》2007,55(10):3936-3943
A heat expansion process similar to that used for expanded bead polystyrene was used to expand starch-based compositions. Foam beads made by solvent extraction had the appearance of polystyrene beads but did not expand when heated due to an open-cell structure. Nonporous beads, pellets, or particles were made by extrusion or by drying and milling cooked starch slurries. The samples expanded into a low-density foam by heating 190-210 degrees C for more than 20 s at ambient pressures. Formulations containing starch (50-85%), sorbitol (5-15%), glycerol (4-12%), ethylene vinyl alcohol (EVAL, 5-15%), and water (10-20%) were studied. The bulk density was negatively correlated to sorbitol, glycerol, and water content. Increasing the EVAL content increased the bulk density, especially at concentrations higher than 15%. Poly(vinyl alcohol) (PVAL) increased the bulk density more than EVAL. The bulk density was lowest in samples made of wheat and potato starch as compared to corn starch. The expansion temperature for the starch pellets decreased more than 20 degrees C as the moisture content was increased from 10 to 25%. The addition of EVAL in the formulations decreased the equilibrium moisture content of the foam and reduced the water absorption during a 1 h soaking period. 相似文献
90.
Shabir A. Bangroo Nayar A. Kirmani Mohammad A. Bhat Javaid A. Wani Asif M. Iqbal Zahoor A. Dar Syed Sheraz Mahdi Ajaz A. Malik 《植物养料与土壤学杂志》2021,184(1):112-122
Background : Potassium (K) availability in soil and plant uptake is restrained by the dynamic interactions among the different pools of K. Aims : To understand these interactions, a study was undertaken to assess the quantity–intensity (Q/I) and buffering characteristics of rainfed maize (Zea mays L.) growing soils. Ten contrasting soils were evaluated for K partitioning changes in exchangeable K (ΔEK) and non‐exchangeable K (ΔNEK) pools in the soil‐solution phase and buffering characteristics using a modified version of Q/I approach. Results : The partitioned Q/I isotherms showed strong adsorption with the increase in K concentration ratio (CRK) and the changes due to ΔEK were higher than changes due to ΔNEK. Total buffering capacity (PBCK) significantly correlated (r = 0.92, p <0.01) with clay content with a major share contributed by buffering capacity owing to non‐exchangeable K ( ) rather than exchangeable K ( ). The fixation capacity (β) factor, the magnitude of added K converted into a non‐exchangeable pool, ranged from 41 to 63%, whereas release (α) factor, the magnitude of added K converted to the exchangeable pool, ranged from 19 to 36%. Both threshold solution K (CKr) and threshold exchangeable K (EKr) values were found to be high in Satran clay loam (S2) and lower in Doon silty clay loam (S3) soils. The equilibrium exchangeable K (EKo) was found close to minimum exchangeable K (Emin) in Doon silty clay loam (S3) and Babaweyl sandy clay loam (S1) soils and overall Emin constituted about 8.94 to 0.57% of the EKo. Conclusion : It may be concluded that K Q/I isotherm partitioning provides a valuable insight to assess the dynamic relations. The ratio of α/β (K recharge index) could be used to evaluate the K enrichment capacity of soil to K additions while EKr and Emin can be potentially useful in the elucidation of exchangeable K as K fertility index especially in soils with poor K fertilizer management. 相似文献