Effects of fertilizer application and fire regime on soil microbial biomass carbon and nitrogen,and nitrogen mineralization in an Australian subalpine eucalypt forest   总被引：3，自引：0，他引：3  

A. K. M. A. Hossain  R. J. Raison  P. K. Khanna 《Biology and Fertility of Soils》1995,19(2-3):246-252

The effects of a range of fertilizer applications and of repeated low-intensity prescribed fires on microbial biomass C and N, and in situ N mineralization were studied in an acid soil under subalpine Eucalyptus pauciflora forest near Canberra, Australia. Fertilizer treatments (N, P, N+P, line + P, sucrose + P), and P in particular, tended to lower biomass N. The fertilizer effects were greatest in spring and smaller in summer and late actumn. Low-intensity prescribed fire lowered biomass N at a soil depth of 0–5 cm with the effect being greater in the most frequently burnt soils. No interactions between fire treatments, season, and depth were significant. Only the lime + P and N+P treatments significantly affected soil microbial biomass C contents. The N+P treatment increased biomass C only at 0–2.5 cm in depth, but the soil depth of entire 0–10 cm had much higher (>doubled) biomass C values in the line + P treatment. Frequent (two or three times a year) burning reduced microbial boomass C, but the reverse was true in soils under forest burn at intervals of 7 years. Soil N mineralization was increased by the addition of N and P (alone or in combination), line + P, and sucrose + P to the soil. The same was true for the ratio of N mineralization to biomass N. Soil N mineralization was retarded by repeated fire treatments, especially the more frequent fire treatment where rates were only about half those measured in unburnt soils. There was no relationship between microbial biomass N (kg N ha^-1) and the field rates of soil N mineralization (kg N ha^-1 month^-1). The results suggest that although soil microbial biomass N represents a distinct pool of N, it is not a useful measure of N turnover.  相似文献   

High prevalence of antibiotic resistance in pathogenic Escherichia coli from large- and small-scale poultry farms in Bangladesh     

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   

Contribution of the polymerization of protein by disulfide bonding to increased gel strength of walleye pollack surimi gel with preheating time     

Mohammed Ismail Hossain  Yoshiaki Itoh  Katsuji Morioka  Atsushi Obatake 《Fisheries Science》2001,67(4):710-717

ABSTRACT: To clarify the contribution of polymerization of myosin heavy chain (MHC) by disulfide bonding to increased gel strength of cooked gel via preheating, the pastes of walleye pollack surimi (SS and C grades) were preheated at 25°C and 40°C for a variety of hours prior to heating at 80°C for 20 min. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns of cooked gels were analyzed with and without reducing the samples, which were solubilized in 8 M urea–2% SDS solution. The formation of polymers by disulfide bonding in cooked gels was almost constant in each of the SS and C grade surimi gels despite the period of preheating. Therefore, it was suggested that polymerization by disulfide bonding occurred during cooking at 80°C and not during preheating.  相似文献   

Inhibiting effect of polymerization and degradation of myosin heavy chain during preheating at 30°C and 50°C on the gel-forming ability of walleye pollack surimi     

Mohammed Ismail Hossain  Yoshiaki Itoh  Katsuji Morioka  Atsushi Obatake 《Fisheries Science》2001,67(4):718-725

ABSTRACT: To confirm the contribution of polymerization and degradation of myosin heavy chain (MHC) during preheating to the gel-forming ability of fish meat paste, walleye pollack surimi paste was preheated at 30°C and 50°C prior to heating at 80°C in the presence of various inhibitors. At 30°C, ethyleneglycol bis(2-aminoethyl ether) -N,N,N ', N '-tetraacetic acid (EGTA) and ethylenediaminetetraacitic acid (EDTA) inhibited gel formation as well as the polymerization of MHC, whereas dithiothreitol (DTT) and leupeptin promoted gel formation, which was accompanied by the enhancement of MHC polymerization and decreased MHC degradation, respectively. At 50°C, leupeptin inhibited MHC degradation and improved gel strength, whereas EGTA, EDTA and DTT had no effect on MHC polymerization and degradation and did not affect gel formation. The results demonstrate that the gel strength of cooked gel (80°C) is not affected by preheating at 30°C and 50°C and does not inhibit polymerization and degradation. Results suggest that the gel strength of cooked gel is dependent on the polymerization and degradation of MHC during preheating.  相似文献   

Variations in the immune response to herpesvirus saimiri in squirrel and rhesus monkeys     

Giancarlo Pizza  Paul H Levine  Dharam V Ablashi  Gary Armstrong  Zakir Bengali  Grace B Cannon 《Comparative immunology, microbiology and infectious diseases》1982,5(4):437-446

Humoral and cell-mediated immunity (CMI) to herpesvirus saimiri (HVS), an oncogenic lymphotropic herpesvirus, was studied in squirrel and rhesus monkeys. Natural antibody to HVS was found in five of six squirrel monkeys but there was no evidence of specific CMI directed against HVS. Rhesus monkeys did not show natural antibody or CMI against HVS antigens. Immunization with HVS, however, produced both antibody and specific CMI in the rhesus monkeys, but no CMI developed in the squirrel monkeys. These findings are important in the development of animal models for the treatment of tumors associated with lymphotropic herpesviruses.  相似文献   

Participatory rural appraisal to identify needs and prospects of market-oriented dairy industries in Bangladesh     

Shamsuddin M  Alam MM  Hossein MS  Goodger WJ  Bari FY  Ahmed TU  Hossain MM  Khan AH 《Tropical animal health and production》2007,39(8):567-581

We assessed resources, challenges and prospects of the dairy industries in four districts of Bangladesh (Mymensingh, Satkhira, Chittagong and Sirajganj) with the participation of 8 to 12 dairy farm families in each district. We used ten participatory rural appraisal (PRA) tools, namely social mapping, semi-structured interview, activity profiles, seasonal calendar, pie charts, mobility diagram, matrix ranking, preference ranking and scoring, system analysis diagram and focus group discussion in 57 PRA sessions from September through October 2002. Dairying contributed more to family income (63 to 74%) and utilized a smaller portion of land than did crops. Twenty seven to 49% of cattle feed is rice straw. Only Sirajganj and Chittagong had limited, periodic grazing facilities. Fodder (Napier; Pennisetum purpureum) cultivation was practiced in Sirajganj and Satkhira. Fodder availability increased milk production and decreased disease occurrence. Friesian crossbred cows were ranked best as dairy cattle. The present utilization of veterinary and AI services was ranked highly. Farmers outside the milk union desired milk purchasing centres as the most required service in the future. They identified veterinary and AI services as inadequate and desired significant improvements. The PRA tools effectively identified resources, constraints, opportunities and farmers’ perspectives related to the dairy industries in Bangladesh.  相似文献   

GROWTH,PHOTOSYNTHESIS, CHLOROPHYLL CONTENT AND NUTRIENT PARTITIONING OF KENAF AS INFLUENCED BY DIFFERENT LEVELS OF CARBON     

M. D. Hossain  M. M. Hanafi  H. Jol  A. H. Hazandy 《Journal of plant nutrition》2014,37(1):65-75

The effects of carbon (C) levels on growth, photosynthesis, chlorophyll content, and nutrient partitioning on five kenaf varieties were investigated. Kenaf plants were grown in pots containing sandy beach ridges interspersed with swales (BRIS) soil. Organic carbon at levels of 0, 10, 20, 30, and 40 t ha^?1, were applied to the pots. The results showed that plant height, stem diameter, leaf number, leaf area, chlorophyll content and photosynthesis rate increased with an increase in carbon levels up to 20 t ha^?1but decreased with additional increase in carbon levels. The proportion of nitrogen in leaves was minimum at 0 and maximum at 20 t ha^?1carbon levels. In stem and roots, proportion of nitrogen (N) decreased after 10 t ha^?1carbon, while in leaves phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) increased after 20 t ha^?1. Variety HC2 showed maximum N, P, and K in leaves and total nutrient content.  相似文献   

Genetic Variance Estimates in Heterogeneous Potato Populations Propagated from True Potato Seed(TPS)     

M K Biswas  M A A Mondal  M Hossain  R Islam 《中国马铃薯》2005,19(2):65-69

Twenty nine cross populations developed according to line x tester mating design along with their twelve parents raised from true potato seeds, were used to study variability and correlation for seven characters. The range of variation for all the characters were found to be wide and pronounced which indicated that characters were quantitative in nature and were under polygenic control. For all the characters, greater portion of the total δ^2p was mostly contributed by the δ^2g. Among the seven characters, tuber weight per plant showed the highest δ^2g, PCV, GCV, H2b, GA and expected GA%.On the other hand, dry matter contents (%) showed the lowest H^2b. Phenotypic and genotypic correlation coefficients of plant height with no. of tubers per plant and tuber weight per plant; no. of branches per plant with no. of tubers per plant and tuber weight per plant were found to be significant and positive.  相似文献   

Estimating Electrical Conductivity for Soil Salinity Monitoring Using Various Soil-Water Ratios Depending on Soil Texture     

M. Shahadat Hossain  G. K. M. Mustafizur Rahman  A. R. M. Solaiman  M. Saiful Alam  M. Mizanur Rahman  M. A. Baset Mia 《Communications in Soil Science and Plant Analysis》2020,51(5):635-644

  相似文献   

Selection of Suitable Parents in the Development of Potato Hybrids in Bangladesh     

M K Biswas　M A A Mondal　M Hossain　R Islam 《中国马铃薯》2005,19(4):193-197

Potatoes(Solanum tuberosum L)are the thirdlargest food crop in Bangladesh following rice andwheat and make a major contribution to the total foodsupply of the country.Although in many westerncountries potato is the number one staple food,it is al-most entirely used as a vegetable in Bangladesh.Thepotato is a short duration crop that produces a largeamount of calories in a short period of time[1].Thepotato produces more protein and calories per unitarea per unit time than any other major food…  相似文献