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71.
根据六年来的资料分析,在东北各地松苗立枯病发生的开始时期,一般多在5月中旬,北部则稍迟;流行盛期在5月下旬至6月上、中旬间,为期将近一个月;发病休止期约在7月初旬至8月中旬,差异比发病开始时期大。病害发生延续期约45—82天,平均发病期为61.4天。红松幼苗发病与流行盛期较晚,与樟子松和落叶松有所不同。三种立枯病菌病苗的出现时期受土壤温度的影响。丝核菌(Rhizoctonia)病苗发生最多在土温18—22℃,腐霉菌(Pythium)在17—22℃,镰刀菌(Fusarium)在23—28℃,所以一般早期发生的病苗主要为丝核菌侵染所致,其次为腐霉菌,在后期则多数为镰刀菌,但如早期土温较高时,亦有较多的镰刀菌病苗。总的发病土温范围是11—30℃,适温为18—25℃,红松幼苗的发病土壤适温还要高些。松苗立枯病在东北地区的流行主要受土壤含水量和降雨量的影响。松苗在生长感染期间,如遇雨量大和次数多或土壤含水量高时,则有利于发病,几天后在流行曲线上即可出现发病率的高峯。土壤温度不是病害流行的主要限制因素,因为在幼苗生长期间,土温范围都适宜于立枯病的发生。在同一地区的发病期间,苗床土壤 pH 值的变动并不显著,故在同一地区病害流行与 pH 值关系亦不大。当年病害发生总百分率的高低,除受气候因素的影响外,还受病害发生延续期长短的影响。如发病延续期久,则总的发病率较高。 相似文献
72.
Effects of dietary substitution of fishmeal with the combined dry microalgae,Nannochloropsis oceanica (NO) biomass residue and casein on growth and body composition of juvenile abalone (Haliotis discus)
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Sung Hyo Myung Won‐Gwan Jung Hee Sung Kim Ye Eun Kim Sung Hwoan Cho Min Seok Jwa Pil Youn Kim Mun Kwan Kim Min‐Woo Park Byeng‐Hak Kim 《Aquaculture Research》2016,47(1):341-348
The effects of dietary substitution of fishmeal with the combined dry Nannochloropsis oceanica (NO) biomass residue and casein on growth performance and carcass composition of juvenile abalone was determined. One thousand two hundred and sixty juvenile abalone were randomly distributed into the 18 L plastic rectangular containers. Five experimental diets in triplicate were prepared. The 28% fishmeal was included into the control (Con) diet. The 25%, 50%, 75% and 100% fishmeal were substituted with the combination of graded levels of dry NO biomass residue and casein, referred to as the NO25, NO50, NO75 and NO100 diets respectively. Finally, the salted sea tangle (ST), Laminaria japonica was prepared to compare the effect of the experimental diets on performance of abalone. The essential amino acids, such as isoleucine, leucine, phenylalanine, threonine and valine tended to increase with dietary substitution of fishmeal with NO biomass residue in the experimental diets. Arginine tended to decrease with dietary substitution of fishmeal with NO biomass residue. Survival of abalone fed the experimental diets was higher than that of abalone fed the ST diet for 16 weeks. Weight gain and specific growth rate (SGR) of abalone fed the NO100 diet were higher than those of abalone fed the all other diets. Weight gain and SGR of abalone linearly increased with dietary substation of fishmeal with NO. Shell length of abalone tended to increase with dietary substitution of fishmeal with the combined dry NO biomass residue and casein. The chemical composition of the soft body of abalone was different among treatments except for moisture content. In conclusion, fishmeal in the diets for abalone could be completely replaced with the combined dry NO biomass residue and casein when the 28% fishmeal was included. 相似文献
73.
Lee YS Lee MH Lee HS Lee SJ Kim YW Zhang R Withers SG Kim KS Lee SJ Park KH 《Journal of agricultural and food chemistry》2008,56(13):5324-5330
Here, we describe the enzymatic synthesis of novel inhibitors using acarviosine-glucose as a donor and 3-alpha-D-glucopyranosylpropen (alphaGP) as an acceptor. Maltogenic amylase from Thermus sp. (ThMA) catalyzed the transglycosylation of the acarviosine moiety to alphaGP. The two major reaction products were isolated using chromatographies. Structural analyses revealed that acarviosine was transferred to either C-7 or C-9 of the alphaGP, which correspond to C-4 and C-6 of glucose. Both inhibited rat intestine alpha-glucosidase competitively but displayed a mixed-type inhibition mode against human pancreatic alpha-amylase. The alpha-acarviosinyl-(1-->7)-3-alpha-D-glucopyranosylpropen showed weaker inhibition potency than acarbose against both alpha-glycosidases. In contrast, the alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen exhibited a 3.0-fold improved inhibition potency against rat intestine alpha-glucosidase with 0.3-fold inhibition potency against human pancreatic alpha-amylase relative to acarbose. In conclusion, alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen is a novel alpha-glucosidase-selective inhibitor with 10-fold enhanced selectivity toward alpha-glucosidase over alpha-amylase relative to acarbose, and it could be applied as a potent hypoglycemic agent. 相似文献
74.
75.
Lin WY Tsai SC Hung GU Kwan PC Lin CF Yuan CS Lin YC 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(1):43-49
In clinical medicine improved diagnostic methods for the detection of infection are needed. A good infectious animal model is very important for the development of a new diagnostic method or drug. The purpose of this study was to establish a good animal model with soft tissue infection. Twenty-four SD rats were divided into four groups (6 in each group). Various bacilli including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), and Escherichia coli (E. coli) were injected intramuscularly into the left caudal thighs of three groups of rats to create soft tissue infection. In addition, normal saline was injected into the left caudal thighs of ten rats which were used as controls. Before and 48 hr after inoculation of the bacilli, a blood sample (0.5 ml) was taken from each rat and analyzed to determine the white blood cell count and differentiated cell count. In addition, 48 hr after the inoculation, 0.2 mCi of gallium-67 was injected via the tail vein. Gallium scan was performed at 24 hr and 48 hr after administration of the radiotracer. The dorsal view of both hind legs was imaged and analyzed by computers to calculate the lesion-to-normal (L/N) ratio. After imaging, all rats were sacrificed and specimens from portions of the infected thigh muscle were sent for histopathologic investigation to confirm the infection. The increase in both the WBC counts and the segmented polymorphonuclear leukocytes (PMNs) were most significant in the S. aureus group, followed by the S. pneumoniae group, E. coli group and normal control groups. The rats with S. aureus infection had significant gallium uptake at the site of infection and the highest L/N ratio of 2.14 on the 24-hr image and 2.0 on the 48-hr image. The rats with S. pneumoniae had the second highest L/N ratio (1.41 at 24 hr, and 1.48 at 48 hr). The L/N ratio for the E. coli group was 1.27 at 24 hr and 1.35 at 48 hr. No obviously abnormal gallium uptake was demonstrated in the normal controls. We conclude that all three bacilli induced a soft tissue infection in SD rats. S. aureus resulted in the most significant infectious signs. 相似文献
76.
Phytoplankton succession in intensive marine shrimp culture ponds treated with a commercial bacterial product 总被引:6,自引:0,他引:6
Succession of phytoplankton dominance was studied in shrimp culture ponds treated with commercial bacterial products. Diatoms were dominant and the cyanobacteria were absent in both treated and control ponds at the beginning of the culture period. After 34 days, the diatoms significantly decreased whereas cyanobacteria increased in both ponds. Chlorophyll a increased from a mean of 35.56 mg m?3 in the first phase to 186.00 mg m?3 in the final phase, and from 42.12 mg m?3 to 242.81 mg m?3 in the treated and control ponds respectively. Cyanobacteria were significantly higher in the control compared with the treated ponds during the final phase of the culture. Algal bioassay showed that the addition of nitrogen either alone or with silica to pond water significantly increased the specific growth rate of Chaetoceros calcitrans. The specific growth rate of Oscillatoria sp. significantly increased when a combination of nitrogen, phosphorus and carbon was added to the pond water. Addition of silica seemed to depress the growth rate of Oscillatoria sp. Nutrient enrichment should be minimized and the supply of nitrogen and silica should be adequate for promoting the growth of beneficial phytoplankton in aquaculture systems. 相似文献
77.
The objectives of the present experiment were to determine the effects on growth factors and some haematological parameters in Korean rockfish, Sebastes schlegeil, after dietary 7,12‐dimethylbenz(a)anthracene (DMBA) exposure at 0.6, 1.2, 2.4 and 4.8 mg kg?1 diet for 8 weeks. The specific growth rate of the fish exposed to DMBA (≥1.2 mg kg?1) showed significantly lower performance than the control. Following 8 weeks of exposure, the DMBA‐exposed groups (2.4 and 4.8 mg kg?1) had a significantly higher mean hepatosomatic index. Condition factor of the fish exposed to DMBA did not show any statistically significant deviation from the control (P>0.05), although the mean values were somewhat lower than those of the control group. Observations on haematological parameters indicated DMBA treatment induced a severe anaemia. Total protein, albumin and total cholesterol concentrations decreased following exposure to DMBA at 2.4 and 4.8 mg kg?1. In contrast, serum bilirubin and blood urea nitrogen in fish exposed to DMBA increased. Significant decreases in serum electrolytes, chloride, phosphorus, magnesium and calcium, and osmolality were observed in all DMBA‐treatment groups. All DMBA‐treatment groups showed a significantly higher activity of lactate dehydrogenase and alkaline phosphatase. Serum transaminase activity after the highest level of 4.8 mg kg?1 DMBA was significantly increased. The key finding from this study is that rockfish exposed to dietary DMBA at concentrations of 1.2 and 2.4 mg kg?1 diet are likely to experience adverse impacts in growth and haematological property respectively. 相似文献
78.
Summary New types of diploids in Brassica crops were synthesized after three consecutive selfing of aneuploids derived from backcrossing of sesquidiploids (2n=29, AAC) with B. campestris (2n=20, AA). The cytogenetic and morphological characteristics of plants with 2n=22, 24 and 40 in the S3 generation were analyzed in order to establish the extent in which these addition and polyploid lines were stabilized. A high frequency of 11II (79.7%), 12II (84.6%) and 20II (100%), were observed at metaphase I of pollen mother cells in 2n=22, 24 and 40 plants, respectively. The chromosome configuration at methaphase II also indicates that a certain level of stability has been attained cytogenetically. Although pollen stainability was relatively high, the seed set percentage was still low. Variation in morphological characteristics indicate the incorporation of one or more chromosome pairs from the C genome of B. oleracea. Other diagnostic characters such as the formation of determinate inflorescence, branching from the base of the stem, and the shift from self-incompatibility to self-compatibility must have resulted from the interaction between A and C genomes. Thus plants with 2n=22, 24 and 40 have been stabilized to some extent and can be developed into new breeding lines of Brassica. It is suggested that limited pollination could be effective in increasing the seed fertility of these plants. 相似文献
79.
Amphotericin B potentiation of rifampicin as an antifungal agent against the yeast phase of Histoplasma capsulatum 总被引:17,自引:0,他引:17
G S Kobbayashi G Medoff D Schlessinger C N Kwan W E Musser 《Science (New York, N.Y.)》1972,177(50):709-710
Rifampicin, at high concentrations, inhibited growth and RNA synthesis in the yeast phase of Histoplasma capsulatum. These effects were potentiated by low concentrations of amphotericin B. The combination of the two agents was fungicidal, whereas each alone, at much higher concentrations, was only fungistatic. 相似文献
80.
Bertram TH Perring AE Wooldridge PJ Crounse JD Kwan AJ Wennberg PO Scheuer E Dibb J Avery M Sachse G Vay SA Crawford JH McNaughton CS Clarke A Pickering KE Fuelberg H Huey G Blake DR Singh HB Hall SR Shetter RE Fried A Heikes BG Cohen RC 《Science (New York, N.Y.)》2007,315(5813):816-820
We present a statistical representation of the aggregate effects of deep convection on the chemistry and dynamics of the upper troposphere (UT) based on direct aircraft observations of the chemical composition of the UT over the eastern United States and Canada during summer. These measurements provide unique observational constraints on the chemistry occurring downwind of convection and the rate at which air in the UT is recycled. These results provide quantitative measures that can be used to evaluate global climate and chemistry models. 相似文献