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71.
本试验以福氏志贺菌和印护突变体(敲除基因,mdoD的福氏志贺菌)为出发菌株,研究了福氏志贺菌基因叩护在低渗和正常渗透压条件下,在标准培养基和洗菜水中对细菌生长、耐热击及耐酸碱能力的影响。试验结果表明:在标准培养基中,opgD突变体生长效率比福氏志贺菌低,提高渗透压后突变体与福氏志贺菌生长曲线相似;在不同的洗菜水中,opgD突变体生长曲线不同,其生长速率明显比福氏志贺菌慢,加盐提高渗透压之后,福氏志贺菌和opgD突变体对数生长期均提前;福氏志贺菌和opgD突变体的抗性试验结果表明:opgD突变体抗热击的能力比福氏志贺菌显著降低,而opgD突变体的耐碱能力却比福氏志贺菌更强。  相似文献   
72.
Understanding variability in seed germination among populations is essential for planning an effective germplasm collection for restoration and conservation purposes.The knowledge of germination and dormancy patterns among populations of desert grasses is crucial for determining the potential of the species and populations to be used for restoration and conservation as well as forage production.Variability in seed germination of Panicum turgidum Forssk and Pennisetum divisum(Gmel.)Henr.in the desert of Kuwait was evaluated in different populations in May 2017.Experiment of seed germination(25 seeds and 4 replicates)was conducted for each population at night/day temperatures of 15℃/20℃and 20℃/30℃under the following light condition:continuous darkness or 12 h/12 h light/dark.Results showed that seed masses of both species strongly varied according to their seed provenances,and both species produced heavier seeds in population with a higher soil electrical conductivity.Seed germination percentage considerably varied between two species,and the variation in P.turgidum was greater(17%–49%)than that of P.divisum(72%–93%).Germination percentage in P.turgidum was greater at high temperature(20℃/30℃)than at low temperature(15℃/20℃).However,temperature regimes had no effect on germination percentage of P.divisum seeds.Mean germination time of both species exhibited significant inter-population variability.This result is especially relevant to assure the selection of the best population of each species and the regeneration success of the species.Besides this,inter-population variability also provides valuable information for enhancing our understanding of the mechanisms that regulate seed germination and how they might be related to seed provenance.  相似文献   
73.
Studies on development of eight species of flat fishes (Psettodes erumei, Brachypleura novae-zeelandiae, Pseudorhombus arsius, Bothus myriaster, Synaptura albomaculata, S. commersoniana, Cynoglossus arel and C. monopus) were carried out with plankton collections and with laboratory reared larvae. The development stages of Cynoglossus arel and C. monopus from egg to metamorphosis are described.  相似文献   
74.
Veterinarians working under remote field conditions are routinely presented with variety of surgical interventions in equines like castrations, management of wound, traumatic and congenital hernias and musculoskeletal disorders thus necessitating the use of general anaesthesia for management of these conditions. The present study was carried out to evaluate and recommend the suitable short term anaesthetic technique for Spiti ponies under field conditions. Seven clinically healthy male Spiti ponies presented for castration were evaluated for short term Total Intravenous Anaesthesia (TIVA) using detomidine (0.02 mg kg(-1)), butorphanol (0.01 mg kg(-1)), 5% guaifenesin (20 mg kg(-1)) and ketamine (2.0 mg kg(-1)). The studies conducted were open label trials and all the animals received same treatment. After proper tetanus prophylaxis and preanesthetic fasting, detomidine was administered intravenously. Subsequently at head down position the animals received butorphanol intravenously. Thereafter, guaifenesin was administered intravenously. As soon as the signs of ataxia developed, the induction of surgical anaesthesia was achieved by intravenous administration of ketamine hydrochloride. The onset of sedation was observed in 2.43 +/- 0.53 min following detomidine administration and the animals were ataxic in 1.43 +/- 0.43 min after butorphanol and guaifenesin administration when ketamine was injected. The ponies were in surgical plane of anaesthesia within 2.28 +/- 0.42 min following ketamine administration. During recovery the limb/head movement and sternal recumbency were attained in 18.71 +/- 1.98 and 26.14 +/- 1.62 min, respectively whereas standing ataxia and normal gait were seen at 29.42 +/- 3.21 and 71.14 +/- 4.74 min, respectively. There was excellent to good muscle relaxation. The surgical anaesthesia remained for 22.57 +/- 1.48 min. The recovery was smooth. Moderate to good suppression of palpebral and corneal reflexes were observed immediately after induction and during anaesthesia. The analgesia was excellent. A highly significant (p < 0.01) to significant (p < 0.05) decrease in respiration rate was observed after induction, during anaesthesia and after recovery. The mean SpO2 value in equines of this group was 76.50 +/- 4.14 and 83.33 +/- 4.18% after induction and during anaesthesia, respectively. Some of the blood biochemical parameters like plasma alanine amino transferase (ALT), total proteins and glucose showed significant increase without clinical consequence. It was concluded that detomidine (0.02 mg kg(-1)), butorphanol (0.01 mg kg(-1)), guaifenesin 5% (20 mg kg(-1)) and ketamine (2.0 mg kg(-1)) combination can safely be used for short term total intravenous anaesthesia in equines under field conditions where the monitoring facilities are meager.  相似文献   
75.
The study of genetic variability is a prerequisite for any tree improvement program. Screening of clones showing the effect of dominance in growth and tree form is essential to identify productive clones, matched to sites. Our study performed in a clonal seed orchard at Lacchiwala of India, represented by 31 clones of Dalbergia sissoo (Shisham) Roxb. from diverse locations revealed significant variability at the 0.1% level of significance in various morphological traits. At the age of 13 years, clone 196 (Gonda) revealed maximum height of 20.2 m and a girth at breast height of 74.2 cm. The five identified clones viz. 196, 198, 192, 123 and 235 were well adapted to the climatic conditions of this zone, hence survived well and showed good performance compared to other clones. Heritability estimates of 87%, 83% and 80% for height, crown width and crown length respectively coupled with high genetic gains indicated strong genetic control of these variables. A correlation matrix of various growth attributes revealed positive correlation among these attributes. On the basis of the entire set of growth variables, the clones were grouped into two major clusters with three subgroups.  相似文献   
76.
Since the dawn of the industrial era, the atmospheric concentrations of several radiatively active gases have been increasing as a result of human activities. The radiative heating from this inadvertent experiment has driven the climate system out of equilibrium with the incoming solar energy. According to the greenhouse theory of climate change, the climate system will be restored to equilibrium by a warming of the surfacetroposphere system and a cooling of the stratosphere. The predicted changes, during the next few decades, could far exceed natural climate variations in historical times. Hence, the greenhouse theory of climate change has reached the crucial stage of verification. Surface warming as large as that predicted by models would be unprecedented during an interglacial period such as the present. The theory, its scope for verification, and the emerging complexities of the climate feedback mechanisms are discussed.  相似文献   
77.
The Indian Ocean Experiment (INDOEX) was an international, multiplatform field campaign to measure long-range transport of air pollution from South and Southeast Asia toward the Indian Ocean during the dry monsoon season in January to March 1999. Surprisingly high pollution levels were observed over the entire northern Indian Ocean toward the Intertropical Convergence Zone at about 6 degrees S. We show that agricultural burning and especially biofuel use enhance carbon monoxide concentrations. Fossil fuel combustion and biomass burning cause a high aerosol loading. The growing pollution in this region gives rise to extensive air quality degradation with local, regional, and global implications, including a reduction of the oxidizing power of the atmosphere.  相似文献   
78.
The viscoelastic properties of high molecular weight polymeric liquids are dominated by topological constraints on a molecular scale. In a manner similar to that of entangled ropes, polymer chains can slide past but not through each other. Tube models of polymer dynamics and rheology are based on the idea that entanglements confine a chain to small fluctuations around a primitive path that follows the coarse-grained chain contour. Here we provide a microscopic foundation for these highly successful phenomenological models. We analyze the topological state of polymeric liquids in terms of primitive paths and obtain parameter-free, quantitative predictions for the plateau modulus, which agree with experiment for all major classes of synthetic polymers.  相似文献   
79.
Summary Generation of Simple Sequence Repeat (SSR) DNA markers was based on the construction of genomic DNA library of avocado (Persea americana M.). The library was screened with the four dinucleotide probes (AG), (AT), (GC) and (CA). Positive clones were sequenced to validate the presence of simple sequence repeats (SSR) and to generate polymerase chain reaction (PCR) primers based on the sequences flanking the simple sequence repeat. Twenty six different pairs of primers which yield a PCR product in the initial screening were synthesized. The SSR A1E11 was found to have eleven alleles while A3F8 has eight alleles. The SSRs in avocado were found to be inherited in a Mendelian fashion.Contribution from the Agricultural Research Organization, The Volcani Center, Bet-Dagan, Israel. No. 1335-E, 1994 series.  相似文献   
80.
Bovine brucellosis is endemic in many parts of the world including India. The disease diagnosis and surveillance are usually carried out by serological tests, which however have drawbacks. This study was undertaken to evaluate the potential of real-time PCR (RT-PCR) targeting bcsp31 gene for surveillance of bovine brucellosis. A total of 461 samples, which included 408 stored serum and 53 prospective blood samples, were used. It was found that 33 (7.15 %) samples were positive by RT-PCR, whereas 149 (32.32 %) and 132 (28.63 %) were positive by Rose Bengal plate test (RBPT) or standard agglutination test (STAT), respectively. The results of this study suggest that RT-PCR targeting bcsp31 gene carried out on DNA extracted from serum or blood may not be a suitable method for surveillance of brucellosis in bovines.  相似文献   
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