印度的主要茶叶产区土壤的主要化学性质

Major chemical properties of tea-growing soils are of paramount importance for better management in a sustainable fashion.Therefore,this study was carried out to understand the major soil chemical properties of major tea（Camellia sinensis L.）-growing areas,Dibrugarh and Tinsukia districts,in the state of Assam,India.A total of 991 surface soil samples were collected from 15 large tea estates（TEs） for analysis of their major chemical properties.Soil pH ranged from 3.61 to 6.81.Total organic carbon and total nitrogen ranged from 2.4 to 47.3 and 0.24 to 3.60 g kg^-1,respectively.All soils were sufficiently rich in plant-available potassium（as K₂O）,which ranged from 127.71 to 252.33 mg kg^-1,exceeding the amount prescribed for optimum tea yield of > 100 mg kg^-1.Plant-available sulfur among soil samples widely varied from 4 to 129 mg kg^-1.Results of hierarchical clustering analysis for homogenous grouping of the 15 TEs based on soil chemical properties showed that the 15 TEs could be classified into three distinct groups which consisted of6,8 and 1 TEs,respectively.Based on the Kolmogorov-Smirnov（K-S） test,the best fitted theoretical probability distributions were found out for different soil chemical properties.It could be concluded that a balanced fertilizer application would be needed as a part of tea improvement program using soil chemical test.     

TUMOUR ASSOCIATED ANTIGENS IN BOVINE HORN CANCER

SUMMARY: Tumour associated antigens in bovine horn cancer (HC) were demonstrated by immunodiffusion in agar gel and by immuno-fluorescence. Antiserums raised in/rabbits against sonicated pooled horn cancer tissue extracts and absorbed with normal antigens, reacted only with HC extracts on agar gel diffusion. Preparations of normal antigen (skin, horn core epithelium, lymph node and liver) and extracts from other tumours (fibroma, fibrosarcoma and myxoma) did not show any reactivity against absorbed antiserum in this test, the absorbed antiserum showing specific reactivity to HC extracts in gel diffusion tests was conjugated to fluorescein isothiocyanate. Many different HC, normal cells and cells from other tumours were incubated with the conjugate and examined by fluorescent microscopy. HC cells showed specific beaded fluorescence on the surface whereas such fluorescence was not observed in normal cells or cells from other tumours.     

Susceptibility of Clostridium perfringens of animal origin to fifteen antimicrobial agents

The minimal inhibitory concentrations of fifteen antibacterial agents were determined by agar-dilution method against 121 strains of Clostridium perfringens isolated from pigs, cattle and poultry. All strains, regardless of host of origin, were susceptible to avoparcin, furazolidone, monensin, nitrovin, penicillin G, ronidazole and tiamulin and resistant to flavomycin. Poultry strains were also susceptible to carbadox, chloramphenicol, erythromycin and virginiamycin. Bacitracin-resistant poultry strains were susceptible to all tested antibacterial agents except tetracycline, but the bacitracin-resistant cattle strains were polyresistant. Porcine strains were susceptible to bacitracin and bovine strains to carbadox. Carbadox-resistant porcine strains were resistant to erythromycin, lincomycin and tetracycline and susceptible to chloramphenicol. Resistance to erythromycin was associated with resistance to lincomycin. High level erythromycin-lincomycin-resistant strains were susceptible to virginiamycin, but the intermediate level erythromycin-lincomycin-resistant cattle strains were resistant to virginiamycin. Resistance to chloramphenicol or erythromycin-lincomycin was always associated with resistance to tetracycline but the reverse was not always true.     

Traditional Parboiled Rice-Based Products Revisited＂ Current Status and Future Research Challenges

Parboiling is an age old technique carried out to improve rice quality. Different grain parboiling techniques have been traditionally followed and scientifically developed for preparation and industrialization of rice. The state of Assam, India produces a large number of rice varieties, some of which are traditionally processed into peculiar parboiled rice products like Hurum, Komal chaul, Bhoja chaul and Sandahguri, which are of both ethnic and possible commercial importances. In spite of extensive research carried out on parboiled rice, these products and their special parboiling techniques have not been sufficiently explored. The status of research on parboiled rice as a whole with special attention to these lesser known speciality products of Assam is extensively reviewed. Future scope of research on these products is also identified.     

Effects of erythromycin-inactivating Lactobacillus crop flora on blood levels of erythromycin given orally to chicks

Germ-free, day-old chickens were colonized with a Lactobacillus fermentum strain isolated from poultry which was able to inactivate in vitro erythromycin and other macrolide and lincosamide antibiotics. Similar control chickens were colonized with a non-degrading L. fermentum strain. Only in chickens colonized with the non-degrading strain were blood levels considered to be therapeutically active achieved with erythromycin in the drinking water. Five groups of broiler chickens of different age originating from three farms all possessed an erythromycin-degrading crop flora. In none of these were therapeutic blood levels attained when erythromycin was given in the drinking water.     

Actinobacteria-enhanced plant growth, nutrient acquisition, and crop protection: Advances in soil, plant, and microbial multifactorial interactions

Agricultural areas of land are deteriorating every day owing to population increase, rapid urbanization, and industrialization. To feed today’s huge populations, increased crop production is required from smaller areas, which warrants the continuous application of high doses of inorganic fertilizers to agricultural land. These cause damage to soil health and, therefore, nutrient imbalance conditions in arable soils. Under these conditions, the benefits of microbial inoculants (such as Actinobacteria) as replacements for harmful chemicals and promoting ecofriendly sustainable farming practices have been made clear through recent technological advances. There are multifunctional traits involved in the production of different types of bioactive compounds responsible for plant growth promotion, and the biocontrol of phytopathogens has reduced the use of chemical fertilizers and pesticides. There are some well-known groups of nitrogen-fixing Actinobacteria, such as Frankia, which undergo mutualism with plants and offer enhanced symbiotic trade-offs.In addition to nitrogen fixation, increasing availability of major plant nutrients in soil due to the solubilization of immobilized forms of phosphorus and potassium compounds, production of phytohormones, such as indole-3-acetic acid, indole-3-pyruvic acid, gibberellins, and cytokinins, improving organic matter decomposition by releasing cellulases, xylanase, glucanases, lipases, and proteases, and suppression of soil-borne pathogens by the production of siderophores, ammonia, hydrogen cyanide, and chitinase are important features of Actinobacteria useful for combating biotic and abiotic stresses in plants.The positive influence of Actinobacteria on soil fertility and plant health has motivated us to compile this review of important findings associated with sustaining plant productivity in the long run.