摘要:

The production of extracellular collagenase by Sreptomyces candidus 91 was strongly influenced by at least two mecanisms. The growth-rate dependent mecanism and part of nature of nitrogen source were suggested by the results obtained in batch cultures and shift-down experiments. Production of collagenase took place in batch culture during growth at intermediate growth rates and was delayed in media supporting high growth rates. Nitrogen source was interfered with collagenase production. Higher collagenase production was obtained with sodium nitrate as sole nitrogen source in nutritive medium. A partial characterization of the activity indicated that it was due to a single metalloprotease with an apparent molecular mass of 170 kDa.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818928

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

Several factors were tested for their influence on the yield and viability of mesophyll protoplasts isolated from P. cerasus L. cv. Montmorency. As optimal conditions were determinated the development of good plants on medium “e” for 10 days. Suitable age of leaves for protoplasts isolations is 10 days cultures. The best viability (95%) of mesophyll protoplasts were obtained using enzyme solution I—Cellulose Onozuca RS—1%; Rhozyme HP—150–1%; Pectolyase Y—23–0.1%. We observed increasing of protoplasts yield and viability after auxin pre-treatment of the leaves. Cultural media based on Murashige and Skoog's (MS) salts supplemented with NAA 0.05 mg/l, BAP -0.5 mg/1 and Z—1 mg/l promoted cell wall regeneration (7th day), the first mitotic division (10–14 days), cell colonies (35 days) and formation the microcalli (65–70 days).

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818915

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

Three species of Steinemema: Steinernema feltiae (Filipjev, 1934), Steinernema kraussei (Steiner, 1923), Steinernema sp. and Heterorhabditis bacteriophora (Poinar, 1976) were recorded from Bulgaria for the first time. Nematodes were isolated from soil samples taken from six natural ecosystems: three near Sofia and three from other parts of the country. Morphometric data are presented for juveniles and males of the studied species.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818916

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

An elctrophoretic analysis of 26 streptomyces strains by 10 enzymes has been performed. Seven enzyme loci assayed have been polymorphic. For each of the enzymes hexokinase and malatdehydrogenase one allele has been registered. The electrophoretic mobility for HEX have been the same for all the studied strains. The investigated streptomyces strains divide into two cluster groups—A and B according to their Rf values. The type strains of the well defined according to Williams four species S. albidoflavus, S. albus, S. fradiae and S. griseus, divide into different clusters. From the species with not definite taxonomic status, S. floridae and S. acrimicini, together with S. griseus (type strain), allocate in one cluster group, as well as the numeric-taxonomic investigation of Kampfer. S. gipsonii, S. rangoon, S. somaliensis also belong to group B. The rest six studied strains with not definite taxonomic status fall into group A, where the mostly heterogeneous subcluster is A2-l, including the type strain of S. albus.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818929

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

It is the Lact, diacetilactis and Lact, cremoris that form the largest amount of diacetyl in the pre-ferment mixed with separately added cultures of lactic acid bacteria and not adding yeast of Sacch. cerevisiae while the L. plantarum and Lact, diacetilactis form the largest amount of acetoin. In that semi-manufacture Lact, lactis and L. bulgaricus form a considerable amount of acetaldehyde. Greater amounts of diacetyl, acetoin and acetaldehyde are found in sour with singly added lactococci unlike the leavens prepared with lactobacilli. The dough showed less content of acetoin and higher of diacetyl. The quantity of the acetaldehyde increases in the dough and to the highest amount in the dough fermented with leaven composed of lactococci in mixture with lactobacilli. Acetoin is formed in the bread crumb as a result of the chemical changes in the acetaldehyde in the process of baking. Part of the diacetyl in the bread crumb originates during the thermal oxidation of acetoin.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818930

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

Ten cultivars of carnation were assessed for their ability to regenerate plants via direct organogenesis. As explants, leaf base of in vitro grown plants and flower buds from green house plants were used. Adventitious shoots apeared after 14 days of cultivation in induction media supplemented with (6-benzylaminopurin and 1-Naphthalenacetic acid). It was proved that the rate of the competence for organogenesis related to the genotype, phytohormone balance in culture media, season and the position of the leaf pairs on the donor plant used as a sourse of explant. The screened cultivars showed different regeneration capacity. Medium with 0.9 mg/l BAP and 0.3 mg/l NAA was suitable for most of the tested plant material. Using petal as an initial explant 8 of the 10 cultivars produced shoots. Regenerants of two cultivars were planted in soil but they showed premature flowering at greenhouse conditions. High regenerable genotype (Nasslada-DR) was selected.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818931

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

Herpesvirus infections in solipedes animals are some of the worst infections due to their more often chronicle course and longer period of virus carrying on the part of infected animals. With regard to making a quick and exact diagnosis the direct electron microscope and immunoelectron microscope methods were tried. The results lead to the conclusion that the direct electron microscope method is a particularly valuable and an exceptionally fast method for spotting and proving the existence of herpesviruses in horses in suspensions obtained from the organs of aborted mare foetuses or dead animals. Through it an early diagnosis may be made as soon as the third hour after the incoming of the material. The immunoelectron microscope method is more sensitive and exact, but requires a longer period of time and preliminary preparations of laboratories. It can be used successfully for making an exact diagnosis in cases where the results acquired by using other laboratory methods are doubtful.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818919

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

The anticarcinogenic activity of living standardized culture of Lactobacillus delbruescii sub. bulgaricus 51-L (LB) was studied on male rats “Whistar”, treated with diethylnitrosamine (DENA). The animals were divided into the following groups: I group—controls; II group—daily LB intake dose of 2 ml/animal with the drinking water; III group—treated with DENA at a dose 130 mg/kg body weight injected intraperitoneally once per week for 8 consecutive weeks; IV group—treated simultaneously with LB and DENA. The animals were monitored during a period of 16 weeks. Their general condition, weight increase, mortality rate and manifestation of tumours were observed. After the observation period the animals were killed and the following parameters were studied: glutathione-S-transferase (G-S-T) activity in liver, macroscopic examination of the animals, histomorphological and histochemical investigation of the suspected ones for tumours and precancerogenic formations as well as liver, kidneys, spleen, lymph nodes, lungs and other (if necessary) target organs. An electronic-microscopic study of liver and morphological-immunologic investigation of spleens were carried out. A high mortality rate was established in DENA treated animals as well as cirrhotic changes of their liver which in the IV group showed a tendency for restriction. Specific G-S-T activity (calculated on the basis of soluble proteins) of liver showed a general tendency for increase in all groups at statistical significance in the group with the combined effect of DENA and LB. The induced tumour genesis mainly hepatic one affected 98% of the animals belonging to the III group and 83% of the animals of the IV group. A diagnostic of the induced benign and malignant tumours was performed. In the IV group statistically significant decrease (p < 0.01) of the number of tumours in a single animal was established versus that of the III group (1.6 versus 3.26), which is an evidence for the inhibiting effect of LB in relation to the DENA-induced cancerogenesis. Immuno-morphometric study on the spleens showed that in the IV group there was certain stimulation of the zones of B-lymphocytes at a preserved suppressive effect of DENA on the zones of T-lymphocytes. The possible mechanisms of the inhibiting effect of LB, which probably include activation of the detoxification mechanisms of G-S-T were also discussed.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818932

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

摘要:

The two cytopatogenic strains of horse herpes virus—1 (KH9F and Vivac) reproduce successfully in primary cellular cultures of swine kidney, as well as in constant cellular lines of swine kidney—SPEV, of rabbit kidney—RK -13 and the line of calf trachea. When compared, RK—13 turned out to be the most sensitive line with quick and maximum accumulation of virus. However the rest of the lines prepared can also be used in the following order: SPEV, calf trachea, primary kidney, and PK—15. The peak moment of the reproduction of virions is the 18 Th. hour and not, as it has hither to been accepted, the 24th hour. After that, between the 24th and 48th hour a complete falling off of the cellular monolayer occurs due to the virus leaving the nucleus and its penetration into the cytoplasm of the contaminated cells.

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818920

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor

ISSN:1310-2818    

DOI:10.1080/13102818.1997.10818933

出版商:Taylor & Francis    

年代:1997

数据来源: Taylor