电刺激大鼠外侧缰核对延髓甩尾相关细胞的活动和甩尾反射的影响

在浅麻醉大鼠上,在延髓腹内侧结构内观察到三种具有不同放电类型的细胞,即乃尾前放电骤停的撤反应细胞,甩尾前放电骤增的给反应细胞和甩尾无关的中性细胞。电刺激外侧缰核可抑制撤反应细胞的自发放电,加强给反应细胞自发放电,从而易化两类细胞的甩尾相关反应,同时易化伤害刺激引起的甩尾反射。实验结果说明,外侧缰核对节段性防御反射有易化作用,这种易化作用可能是通过延髓内撤反应和反应细胞的协同活动而实现的。     

DNA fingerprint bands applied to linkage analysis with quantitative trait loci in chickens

Summary
An efficient approach to detect association between quantitative traits and bands of DNA fingerprint patterns uses intra-family tail analysis, which compares fingerprints of DNA mixes from individuals at the two tails of a phenotypic distribution. In analysis of 67 paternal half-sibs of a meat-type chicken family, of 57 sire bands generated by two probes, one sire-specific band (S6–6) was associated with abdominal fat deposition. The band effect was estimated by a linear model analysis to be 0–88 standard deviations, or about 30% of the family mean. The association between band S6–6 and abdominal fat was further examined by testing progeny of paternal half-sibs of the chickens which were used in the tail analysis, establishing genetic linkage between the DNA marker and a genetic locus affecting abdominal fat deposition.     

Normal rat kidney proximal tubule cells in primary and multiple subcultures

Summary Anin vitro model to establish primary and subcultures of rat kidney proximal tubule (RPT) cells is described. After excising the kidneys and separating the cortex, the cortical tissue is digested with the enzyme DNAse-collagenase (Type I) resulting in a high yield of viable RPT Cells. The isolated RPT cells are then seeded onto rat tail collagen-coated surfaces and grown to confluency in a serum-free, hormonally defined medium. The cell yield can be increased by transfering the conditioned medium on Day 1 to more rat tail collagen-coated surfaces. RPT cell attachment and morphology was better on rat tail collagen-coated surfaces than on bovine collagen Type I coated surfaces. The culture medium was a 1∶1 mixture of Ham’s F-12 and Dulbecco’s modified Eagle’s medium supplemented with bovine serum albumin, insulin, transferrin, selenium, hydrocortisone, triiodothyronine, epidermal growth factor, and glutamine. The RPT cells became confluent in 7–10 d, at which point they could be subcultured by trypsinizing and growth in the same medium. In some studies, 10 ng/ml cholera toxin was added to the culture medium. We could passage the RPT cells up to 14 times in the presence of cholera toxin. The cells were investigated for activity of several markers. The cells were histochemically positive for alkaline phosphatase and γ-glutamyl transpeptidase activity and synthesized the intermediate filament pankeratin. The RPT cells displayed apically directed sodium-dependent active glucose transport in culture. Hence, the RPT cells retain structural and functional characteristics of transporting renal epithelia in culture. This rat cell culture model will be a valuable tool for substrate uptake and nephrotoxicity studies.     

Role of water receptor in the frog

To elucidate the role of the water receptor in the frog (Rana catesbeiana), reflex activities elicited by its excitation were studied. Application of tap water to the oral mucosa depressed the rhythmical movement of gorge (buccal) respiration, accompanied by an elevation of the inner pressure of the oral cavity (buccal pressure). Tonic reflex discharges were elicited in the nerves innervating the submental and submaxillary muscles, which close the nostrils, the pterygoid and the profound portion of the major masseter muscles, which produce a strong bite, and the geniohyoid and hyoglossus muscles, which elevate buccal pressure. These muscles, except for the pterygoid, also participate in the rhythmical movement of gorge respiration as expiratory muscles. Rhythmical movements in the minor masseter and sternohyoid muscles, which act as inspiratory muscles in gorge respiration, were depressed by the water stimulation of the oral mucosa. These findings indicate that the water receptor plays a role in the interruption of gorge respiratory movements, accompanied by an elevation of buccal pressure.     

Entry of immotile spermatozoa into zona-free hamster ova

We studied six men whose spermatozoa were immotile and possessed a variety of sperm tail structural abnormalities by electron microscopy. The semen of all six subjects had a normal percentage of oval forms and sperm undergoing capacitation and acrosome reaction. Despite the absence of motility, when incubated sperm from these subjects was added to a microdrop of medium containing zona pellucida-free hamster ova, sperm penetration or entry into the cytoplasm of from 1–9% of the eggs was evident with phase contrast microscopy. This latter finding suggests that, at least in this system, oocytes actively facilitate sperm incorporation. Penetration was absent when sperm of fertile men were rendered immotile, though still viable, by heat treatment.     

Tail raising by baboon mothers toward immigrant males

Behavioral responses of adult females to recently immigrated adult males were examined in two groups of chacma baboons in the Moremi Wildlife Reserve, Botswana. Mothers carrying infants respond negatively by raising their tails, avoiding, and screaming when in proximity to immigrant males. These responses are not given by mothers when their infants are away from them or by females who do not have infants. Also, the negative responses by mothers carrying infants are given only to immigrant males and not to long-term resident males. These observations are in concordance with the growing evidence of infanticide in savanna baboon societies: mothers would be expected to show negative responses to potentially aggressive males, particularly immigrants. There was evidence to suggest that mothers respond negatively to immigrants only insofar as these males could not have sired their infants. If confirmed by subsequent observations, this result would lend support to the sexual selection model of infanticide.     

Expression of a gene encoding a rabbit sperm membrane protein in mammalian cells.

A general mammalian expression vector designated pSV2-EP was reconstructed by inserting an oligonucleotide fragment into pSV2-dhfr. This vector allowed insertion of cDNAs with EcoRI cohesive ends. The pSV2-EP contains a simian virus 40 (SV40) early promoter, origin for DNA replication, SV40 poly-A site, splicing site, an initiator ATG downstream from the promoter and an EcoRI site for the insertion of cDNA fragment screened from lambda gt11 expression libraries. A recombinant plasmid (pS-VRS-1) was constructed by inserting RSD-1, a cDNA encoding a rabbit sperm tail protein, into the EcoRI site of the pSV2-EP vector. Chinese hamster ovarian (CHO) dhfr-negative cells were cotransformed with pSV2-dhfr and pSVRS-1 by the calcium phosphate method. In selective culture medium without thymidine and hypoxanthine, several cell lines were obtained containing mRNA and DNA that hybridized with RSD-1. One of these transformed cell lines stained intensely with anti-rSMP-B antibodies, demonstrating that the RSD-1 was expressed in the transformed CHO cells.     

反萼银莲花的核型分析

本文报道反萼银莲花的染色体数目及核型。其核型公式为K(2n)=6m+4sm(1SAT)+4st(1SAT)+2t,按照Stebbins的核型对称性分类标准应属于“2A”型。同时对本属的进化等问题也作了初步讨论。     

Implementation of reflex loops in a biomechanical finite element model

In the field of biomechanics, the offer of models which are more and more realistic requires to integrate a physiological response, in particular, the controlled muscle bracing and the reflexes. The following work aims to suggest a unique methodology which couples together a sensory and motor loop with a finite element model. Our method is applied to the study of the oscillation of the elbow in the case of a biceps brachial stretch reflex. The results obtained are promising in the purpose of the development of reactive human body models.