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1998年  第19卷  第2期

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研究论文
Snake venoms,especially those from the two subfamilies,Crotalinae and Viperinae,contained a lot of serine proteases.They were responsible for the hemorrhage,shock,or disorder of blood coagulation after envenomation.They acted,by activating,inactivating,or other converting effects,on almost all the components of hemostatic and fibrinolytic systems.Their sequences were homologous to trypsin-kallikrein serine proteases.Variation of primary sequences out of active center results in the difference of substrate specificities and the further difference of biological and pharmacological activities.Because of their common and unique properties compared to their physiological corresponding factors,snake venom proteases are proved to be an excellent model for the study of protease substrate discriminating mechanism.Furthermore,they have found an important position both in basic research and application of hemostasis and thrombosis in clinic.
The occurrence of calcitonin gene-related peptide(CGRP)and its mRNA was studied in lungs of Macaca mulatta using ABC-GDN immunohistochemistry and in situ hybridization.The results demonstrated that CGRP was located in neuroendocrine cells (NEC) and neuroepithelial bodies (NEB),including all airways from bronchi,bronchioles and alveolar ducts.The distribution of CGRP hybridization positive cells was similar to that previously discribed with immunohistochemistry.Labelling for CGRP mRNA was evenly distributed over the cytoplasm,whereas CGRP was usually of high intensity toward the base of neuroendocrine cells,suggesting basal accumulation of synthesized peptide.The nerve fibers in walls of the intrapulmonary bronchi and blood vessels were also CGRP positive.Adjacent sections immunostained with antibodies to CGRP and 5-hydroxytryptamin (5-HT) proved the coexistance of CGRP and 5-HT in NEC and NEB.This finding suggests the possibility of functional interaction of CGRP with 5-HT.
Aerial resting metabolic rates V [mlO[2]/(kg·h)] and respiratory gas exchange rates RE of 20-60 g juvenile soft-shelled turtles were measured under 23℃,25℃,28℃,30℃,33℃ and 35℃.The resting metabolic rate in air had a direct ratio with temperature T(℃)and their relationship could be described as:V=8.2217×10 [0.0459],R[2]=0.98.Q[10] value was 2.5 between 23-30℃ while it was 3.4 between 30-35℃.RE decreased slowly with increasing temperature between 23-30℃,while above 30℃,a sharp decrease in RE was found.Some metabolic characters of juvenile soft-shelled turtles were discussed.
In this study,the effect of high Ca[2+] level by injecting CaCl[2] into bilateral hippocampus on the learning and memory behavior of young mice was investigated,and the synaptic structural parameters in the hippocampal CA[3] area were quantitatively analysed.The main results were as follow,compared with control:(1) The STL(step-through latency)of CaCl[2] group was shortened in one trial passive avoidance response,and the descrimination learning capacity of CaCl[2] group in Y-maze was greatly attenuated (P<0.01),showing the severe impairment of learning and memory in this group.(2) The thickness of post-synaptic density (PSD)of CaCl[2] group was thinned significantly (P<0.001),while the width of synaptic cleft of this group was apparently increased (P<0.05).These results suggested that the learning and memory dysfunction caused by over-loaded calcium ions in hippocampus might based on the morphological changes of the synaptic interface stucture.
Restriction fragment length polymorphism (RFLP) of mitochondrial DNA (mtDNA) from Zhejiang native pigs and wild boars was analyzed by using 25 restriction endonucleases,I.e.ApaⅠ,AvaⅠ,Bam HⅠ,BclⅠ,BglⅠ,BglⅡ,ClaⅠ,DraⅠ,Eco RⅠ,Eco R V,Hae Ⅱ,Hin cⅡ,Hin dⅢ,HpaⅠ,KpnⅠ,PstⅠ,PvuⅠ,PvuⅡ,SacⅡ,SalⅠ,Sca Ⅰ,SmaⅠ,StuⅠ,XbaⅠand XhoⅠ,which recognize six nucleotides.In the 30 analyzed individuals,30 restriction morphs,which could be sorted into 3 haplotypes,were detected.Four new morphs,I.e.Bam HⅠ-B,BclⅠ-B,DraⅠ-B and XbaⅠ-C were detected.The average genetic distance (P) was 0.005,and the value of average nucleotide diversity (π) in pig population(including native pigs and wild boars)was 0.0008.This suggested that the genetic diversity of pigs was remarkably scarce.The pigs in Zhejiang might have originated from a late common ancester.Combining with the data from previously reports,it was suggested that the Jinhua strain Ⅲ pigs may have two female origins.
The secondary-structural features of TATA box is important for the initial process of RNA transcription in eukaryotic.After observing the secondary-structures of 142 genes promotor sequences,we proposed this structural model of the stems and loops for the nucleotide sequences of the TATA box in eukaryotic.Our results suggested that the structural features of TATA box in structural models of the stems and loops were closely associate with the recognition and interaction of the transcription factor and RNA polymerase.We got a consistent result by comparing with the corresponded secondary-structural features of E.coli.Among the distribution of hairpin,interloop,and single strand there was a difference.
Based on the comparison and analysis on the sequences of cytochrome c family and some domain fragments in immunoglobulin family,the protein amino acid residue accessibilities have been calculated,and the relationship between amino acid residue accessibilities,protein sequences and three-dimensional structural conservativeness has been analyzed and discussed.The results indicated that all conserved residues in sequences have lower accessibilities,and the conserved residues with lower accessibilities are close correlative to keeping protein specific threedimensional structures.It is suggested that protein structural conservativeness is mainly expressed in their three-dimensional structures between evolutionary distant various protein molecules within families of proteins,and the conserved residues in sequences play an important role to keep specific three-dimensional structure in whole protein molecule.In addition,it is found that the conserved residues in sequences are generally located in the interior of whole protein molecular structure.This is why their accessibilities are lower.Of course,not all lower accessible residues are conserved,but the conserved residues are those with lower accessibilities.
In this paper humerus and clavicula of adult Taihang Mountains Macaca mulatta were measured and observed.Five indexes were counted.Parts of the measured data and indexes in the provinces,Henan (M.m.tcheliensis),Sichuan (M.m.lasiotis),Yunnan (M.m.mulatta),Hubei and Hunan (M.m.littoralis) of China were clustered.The results of cluster analyses showed that morphology of Taihang Mountains Macaca mulatta was more suitable to locomotion of the ground than the others,and movement of Taihang Mountains Macaca mulatta on the ground was more than the others and its movement in trees was less than the others .
In this paper two new genera and two new species of Empriini,Allantinae from China are described:Blennallantus compressicornis gen.Et sp.nov.,Allanempria rufithoracica gen.Et sp.nov.The type specimens are deposited in the Insect Collection of the Central South Forestry University.
Two new species and a known species of Collembola are described or redescribed from Yunnan Province,southwest China,Hypogastrura xiaoi sp.nov.,H.zhangi sp.nov.and Paranurophorus simplex Denis,1928,respectively.The last species is the second record from China since 1928.
Two new ant species from the tropical rain forest of Xishuangbanna Nature Reserve in Yunnan Province,Mystrium oculatum sp.nov.and Cryptopone recticlypea sp.nov.,were described.The genus,Mystrium Roger,was first recorded in China.
Recent attempts to improve the recipients pregnancy rates via the improvement of embryo quality and the proper selection and management of recipients were discussed in this review.Embryo quality can be improved by two distinct pathways with regard to their origin.The quality of embryos produced by superstimulation can be improved by optimizing the dosage regimens and types of gonadotropin preparations and,recently,by monitoring the follicular dynamics and the quality of embryos produced by in vitro maturation,fertilization and development can be improved by co-culture with oviductal or granulosa cells,providing necessary nutrients,growth factors as well as optimizing the in vitro culture nvironment.The quality of the recipients can be guaranteed by following current guidelines regarding the genotypes,health,nutrition and physiology for proper selection and management of recipients.The future research trends in this endeavor were also considered in this review.