密点麻蜥几种组织SDH和LDH活性对温度的适应

研究了密点麻蜥肝脏、骨骼肌、大脑组织中琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)活性对温度的依赖关系.结果表明:密点麻蜥3种组织中SDH在5～35℃范围内随温度的升高而升高,在35℃时达到峰值后随着温度的升高而下降,35℃可能为SDH的最适温度;3种组织的LDH活性随温度的升高而升高;大脑中的SDH和LDH活性最高.这表明SDH和LDH的活性与动物组织的能量代谢相适应.     

温度对白条锦蛇SDH、LDH活性及LD含量的影响

在不同温度条件下,测定了白条锦蛇Elaphe dione骨骼肌中琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)的活性以及骨骼肌、肝脏和肾脏中乳酸(LD)的含量.结果 表明,温度从10℃上升到35℃,SDH的活性先增高后降低,而LDH的活性和LD的含量随温度升高持续升高.说明白条锦蛇的能量供给方式与这种动物的喜好温度有密切关系.     

温度对虎斑颈槽蛇消化酶活性的影响

研究了不同温度下虎斑颈槽蛇胃、胰腺、小肠的蛋白酶、淀粉酶、脂肪酶的活性。结果表明,随着温度的升高,各种酶的活性在一定范围之内均表现为升高。在不同组织中同一种酶活性存在差异。3种组织中,蛋白酶的最适温度均为40℃;胃和胰腺淀粉酶的最适温度为35℃,小肠淀粉酶为30℃;胰腺脂肪酶的最适温度为30℃,小肠脂肪酶为35℃。     

虎斑颈槽蛇颈腺的解剖观察研究

虎斑颈槽蛇颈腺的解剖观察研究吴卯斌（安徽省黄山市屯溪毒蛇养殖研究所２４５０５１）关键词虎斑颈槽蛇，颈腺，解剖我所多年从事毒蛇的人工养殖研究工作，在进行蛇类饲养，观察过程中，一次偶尔触怒虎斑颈槽蛇（Ｒｈａｂｄｏｐｈｉｓｔｉｇｒｉｎｕｓ）［又名虎斑游蛇］...     

室温条件下虎斑颈槽蛇卵的孵化与幼蛇饲养

目的探讨室温条件下虎斑颈槽蛇的孵化及幼蛇饲养情况。方法选用同一条虎斑颈槽蛇产的同窝蛇卵31枚,随机为A组（实验组）、B组（对照组）,A组16枚,B组15枚。两组蛇卵分别置于2个完全相同的打孔整理箱中进行孵化,孵出幼蛇用小泽蛙饲养。结果在室温条件下,孵化期58天,孵化率为96．77％。出壳后7～9天,幼蛇第1次蜕皮,蜕皮周期在11～16天不等。结论对虎斑颈槽蛇进行工厂化人工养殖是切实可行的。     

一种有毒的游蛇——虎斑颈槽蛇

虎斑颈槽蛇是中国数量较多、分布最广的蛇类之一,但一直被当作无毒蛇而忽视。为了使人们对虎斑颈槽蛇有一个全面、正确的认识,也为以后的相关研究奠定一定的理论基础,从虎斑颈槽蛇的分布,形态,生活习性以及毒腺的研究等方面加以综述。     

肌酸对游泳大鼠乳酸、糖原含量和乳酸脱氢酶活性的影响

为探讨肌酸对提高大鼠运动能力的作用 ,观察了肌酸对游泳大鼠血清、心肌和骨骼肌乳酸、糖原含量和乳酸脱氢酶 (LDH)活性的影响。实验用雄性wistar大鼠 2 4只 ,随机分为正常组、游泳对照组和游泳补充肌酸组。两个游泳组每天游泳训练 1h,9天后 ,游泳 4h ,测定血清、心肌和骨骼肌乳酸水平 ,测定血清和骨骼肌乳酸脱氢酶活性以及心肌与骨骼肌糖原含量。结果显示 :肌酸可抑制游泳运动后大鼠血清、心肌和骨骼肌乳酸浓度以及血清LDH活性的升高幅度 ,抑制心肌和骨骼肌糖原含量及骨骼肌LDH活力的下降。以上结果表明 ,肌酸可改善运动后机体乳酸和糖原的代谢 ,降低运动性疲劳 ,提高大鼠的运动能力     

砷对兰州鲇组织中代谢酶活性及RNA和蛋白质含量影响

采用毒性试验方法,研究了安全浓度（1.288 mg/L）条件下亚砷酸钠（NaAsO2）对兰州鲇（Silurus lanzhouensis）脑、鳃、肝脏、肌肉4种组织中6-磷酸葡萄糖脱氢酶（G-6-PDH）和乳酸脱氢酶（LDH）活性,以及RNA和蛋白质含量的影响。结果表明,染毒21d时,As（Ⅲ）可显著降低4种组织中G-6-PDH和LDH活性、RNA和蛋白质含量（P0.05）。撤毒后21d,除脑和肝组织中蛋白质含量未恢复到对照组水平（P0.05）,肝脏中G-6-PDH活性超过了对照组水平（P0.05）外,其余各组织中G-6-PDH和LDH活性、RNA和蛋白质含量均可恢复到对照组水平（P0.05）。以上结果表明,As（Ⅲ）对兰州鲇组织中代谢酶活性具有明显的抑制作用,可致组织细胞RNA损伤和可溶性蛋白质减少,但这种影响是可逆的,撤毒后一定时间内可恢复到正常水平。       

虎斑颈槽蛇中国大陆亚种颈背腺毒液的研究

虎斑颈槽蛇中国大陆亚种（Rhabdophis tigrinus lateralis）具有已知蛇类中罕见的颈背腺及其毒液。肉眼观察发现腺体呈珠球状,8～13对腺体呈平行排列,腺体间隔分布;组织切片观察发现,腺体上无开口,无合成毒液的细胞器;实验表明毒液有神经毒性,对小白鼠的半致死量（LD50）为97．99mg／kg,SDS-PAGE电泳呈现4条蛋白条带。虎斑颈槽蛇中国大陆亚种颈背腺毒液很可能作为一种特殊辅助防御系统,增强DuvemoY腺毒液的防御作用。     

日本血吸虫性病兔肝纤维化的酶组织化学研究

目的观察日本血吸虫感染家兔导致肝脏发生纤维化后的肝组织酶学改变.方法将23只成年健康大耳白兔分为正常对照组(N)8只,模型组(M)15只,M组采用腹贴法(日本血吸虫尾蚴180条/只,持续15min)感染血吸虫,六周后服用吡喹酮行杀虫治疗.于实验的第13周将全部动物麻醉后剖腹取肝组织.肝组织行HE染色和电镜观察;酶组织化学方法检测单胺氧化酶(MAO)、一氧化氮合酶(NOS)、琥珀酰脱氢酶(SDH)、乳酸脱氢酶(LDH)在器官的表达活性.结果在血吸虫感染家兔的第13周可观察到肝组织明显纤维化;模型组中MAO、NOS、LDH活性明显高于正常对照组,而SDH活性则明显降低.结论慢性血吸虫感染引起的肝纤维化导致肝细胞缺血缺氧,影响NOS、SDH、LDH活性,加重肝细胞损伤.     

Implication of basal lamina dependency in survival of Nrf2-null muscle stem cells via an antioxidative-independent mechanism

Nuclear factor erythroid 2–related factor 2 (Nrf2) is a master regulator for the induction of antioxidative genes and plays roles in diverse cellular functions. The roles of Nrf2 in muscle regeneration have been investigated, and both important and unimportant roles of Nrf2 for muscle regeneration have been reported. Here, using aged Nrf2-null and Nrf2–dystrophic double-null mice, we showed nonsignificant phenotypes in the muscle regeneration ability of Nrf2-null mice. In contrast with these results, strikingly, almost all Nrf2-null muscle stem cells (MuSCs) isolated by fluorescence-activated cell sorting died in vitro of apoptosis and were not rescued by antioxidative reagents. Although their proliferation was still impaired, the Nrf2-null MuSCs attached to myofibers activated and divided normally, at least in the first round. To elucidate these discrepancies of MuSCs behaviors, we focused on the basal lamina, because both in vivo and single myofiber culture allow MuSCs within the basal lamina to become activated. In a basal lamina–disrupted model, Nrf2-null mice exhibited remarkable regeneration defects without increased levels of reactive oxidative species in MuSCs, suggesting that the existence of the basal lamina affects the survival of Nrf2-null MuSCs. Taken together, these results suggest that the basal lamina compensates for the loss of Nrf2, independent of the antioxidative roles of Nrf2. In addition, experimental conditions might explain the discrepant results of Nrf2-null regenerative ability.     

增加刺激频率不影响大鼠萎缩比目鱼肌强直收缩疲劳性

为观察模拟失重对大鼠比目鱼肌（soleus,SOL）与趾长伸肌（extensor digitorum longus,EDL）间断强直收缩功能的影响,以及对刺激频率的调节作用,采用离体骨骼肌条灌流技术,观测其产生强直收缩最大张力的最适刺激频率、疲劳性与疲劳后恢复过程。结果表明：对照组大鼠SOL强直收缩的最适刺激频率为60Hz,尾部悬吊1周大鼠SOL的最适刺激频率亦为60Hz,尾部悬吊2周后,其最适刺激频率增高为80Hz,4周后则为100Hz;在最适刺激频率作用下,悬吊大鼠SOL间断强直收缩的最大张力（Po）在悬吊1与2周未见改变,第4周才呈现显著性降低（P〈0．01）。间断强直收缩5min后,对照组大鼠SOL张力降低到22．8％Po：悬吊1、2与4周组疲劳性均增加,与其同步对照组相比均有显著性差异（P〈0．01）。疲劳性强直收缩后,在20min内对照大鼠SOL张力基本恢复到疲劳前水平,而悬吊1、2与4周组则不能完全恢复（P〈0．05）。对照组大鼠EDL的最适刺激频率为120Hz,悬吊1、2与4周组EDL的最适刺激频率、疲劳性以及疲劳后恢复过程均未发生改变。以上结果提示,增加刺激频率可对悬吊1与2周大鼠SOL强直收缩最大张力的降低有代偿作用,但不能代偿悬吊4周大鼠SOL最大收缩张力的降低,亦不影响悬吊大鼠SOL间断强直收缩疲劳性的增加与疲劳后恢复的减缓。     

Transgenic and tissue culture analyses of the muscle creatine kinase enhancer Trex control element in skeletal and cardiac muscle indicate differences in gene expression between muscle types

The muscle creatine kinase (MCK) gene is expressed at high levels only in differentiated skeletal and cardiac muscle. The activity of the cloned enhancer–promoter has previously been shown to be dependent on the Trex element which is specifically bound by a yet unidentified nuclear factor, TrexBF. We have further characterized the function of the Trex site by comparing wild-type and Trex-mutated MCK transgenes in five mouse skeletal muscles: quadriceps, extensor digitorum longus (EDL), soleus, diaphragm, and distal tongue, as well as in heart ventricular muscle. Several types of statistical analysis including analysis of variance (ANOVA) and rank sum tests were used to compare expression between muscle types and between constructs. Upon mutation of the Trex site, median transgene expression levels decreased 3- to 120-fold in the muscles examined, with statistically significant differences in all muscles except the EDL. Expression in the largely slow soleus muscle was more affected than in the EDL, and expression in the distal tongue and diaphragm muscles was affected more than in soleus. Median expression of the transgene in ventricle decreased about 18-fold upon Trex mutation. Transfections into neonatal rat myocardiocytes confirmed the importance of the Trex site for MCK enhancer activity in heart muscle, but the effect is larger in transgenic mice than in cultured cells.     

Water compartments in living,glycerinated and fixed skeletal muscles of the frog

Summary The kinetics of water replacement with heavy water (deuterium oxide) in the gastrocnemius and sartorius muscles of the frog under isotonic conditions, studied both gravimetrically and by infrared photometry, reveals three water compartments: (i) non-exchangeable ( 80 ml/kg fresh weight), (ii) slowly exchanging ( 500 ml/kg fresh weight), (iii) rapid exchanging — extracellular ( 200 ml/kg fresh weight). Exposure to both glycerol and glutaraldehyde increases the permeability coefficients and the amount of rapid exchanging water; glutaraldehyde also increases the amount of nonexchangeable water. Approximately 90% of the water is kept in the tissue only by weak intermolecular forces, the energies of which amount to 1 kcal/mol. The amount of non-exchangeable water is equivalent to about six continuous adsorption layers covering the myofilaments. Approximately 70 % of the tissue water appears to be replaced by glutaraldehyde during standard fixation.     

Electron microscopy and 3D reconstruction of F-actin decorated with cardiac myosin-binding protein C (cMyBP-C)

Myosin-binding protein C (MyBP-C) is an ∼ 130-kDa rod-shaped protein of the thick (myosin containing) filaments of vertebrate striated muscle. It is composed of 10 or 11 globular 10-kDa domains from the immunoglobulin and fibronectin type III families and an additional MyBP-C-specific motif. The cardiac isoform cMyBP-C plays a key role in the phosphorylation-dependent enhancement of cardiac function that occurs upon β-adrenergic stimulation, and mutations in MyBP-C cause skeletal muscle and heart diseases. In addition to binding to myosin, MyBP-C can also bind to actin via its N-terminal end, potentially modulating contraction in a novel way via this thick-thin filament bridge. To understand the structural basis of actin binding, we have used negative stain electron microscopy and three-dimensional reconstruction to study the structure of F-actin decorated with bacterially expressed N-terminal cMyBP-C fragments. Clear decoration was obtained under a variety of salt conditions varying from 25 to 180 mM KCl concentration. Three-dimensional helical reconstructions, carried out at the 180-mM KCl level to minimize nonspecific binding, showed MyBP-C density over a broad portion of the periphery of subdomain 1 of actin and extending tangentially from its surface in the direction of actin's pointed end. Molecular fitting with an atomic structure of a MyBP-C Ig domain suggested that most of the N-terminal domains may be well ordered on actin. The location of binding was such that it could modulate tropomyosin position and would interfere with myosin head binding to actin.     

Ciliary muscle contraction force and trapezius muscle activity during manual tracking of a moving visual target

Previous studies have shown an association of visual demands during near work and increased activity of the trapezius muscle. Those studies were conducted under stationary postural conditions with fixed gaze and artificial visual load. The present study investigated the relationship between ciliary muscle contraction force and trapezius muscle activity across individuals during performance of a natural dynamic motor task under free gaze conditions. Participants (N = 11) tracked a moving visual target with a digital pen on a computer screen. Tracking performance, eye refraction and trapezius muscle activity were continuously measured. Ciliary muscle contraction force was computed from eye accommodative response. There was a significant Pearson correlation between ciliary muscle contraction force and trapezius muscle activity on the tracking side (0.78, p < 0.01) and passive side (0.64, p < 0.05). The study supports the hypothesis that high visual demands, leading to an increased ciliary muscle contraction during continuous eye–hand coordination, may increase trapezius muscle tension and thus contribute to the development of musculoskeletal complaints in the neck–shoulder area. Further experimental studies are required to clarify whether the relationship is valid within each individual or may represent a general personal trait, when individuals with higher eye accommodative response tend to have higher trapezius muscle activity.     

Distinction between smooth muscle,fibroblasts and endothelial cells in culture by the use of fluoresceinated antibodies against smooth muscle actin

Summary FITC-labelled antibodies against native actin from chicken gizzard smooth muscle (Gröschel-Stewart et al., 1976) have been used to stain cultures of guinea-pig vas deferens and taenia coli, rabbit thoracic aorta, rat ventricle and chick skeletal muscle. The I-band of myofibrils of cardiac muscle cells and skeletal muscle myotubes stains intensely. In isolated smooth muscle cells, the staining is located exclusively on long, straight, non-interrupted fibrils which almost fill the cell. Smooth muscle cells which have undergone morphological dedifferentiation to resemble fibroblasts with both phase-contrast microscopy and electronmicroscopy still stain intensely with the actin antibody. In those muscle cultures which contain some fibroblasts or endothelial cells, the non-muscle cells are not stained with the actin antibody even when the reactions are carried out at 37° C for 1 h or after glycerination. Prefusion skeletal muscle myoblasts also do not stain with this antibody.It is concluded that the actin antibody described in this report is directed against a particular sequence of amino acids in muscle actin which is not homologous with non-muscle actin. The usefulness of this antibody in determining the origin of cells in certain pathological conditions such as atherosclerosis is discussed.This work was supported by the Life Insurance Medical Research Fund of Australia and New Zealand, the National Heart Foundation of Australia, the Deutsche Forschungsgemeinschaft and the Wellcome Trust (London). We thank Janet D. McConnell for excellent technical assistance     

The relationship of creatine kinase variability with body composition and muscle damage markers following eccentric muscle contractions

[Purpose]

The purpose of the study was to investigate the relationship between CK variability and body composition and muscle damage markers following eccentric exercise.

[Methods]

Total 119 healthy male subjects were recruited to perform 50 eccentric contractions consisted of 2 sets of 25 contractions. Then, blood creatine kinase (CK) activity was analyzed to divide into three groups based on their CK activity levels. Maximum isometric strength (MIS), muscle soreness (SOR) and body composition data were obtained before and after exercise.

[Results]

The results showed that high CK responders had a significant decrease in MIS (p<0.001) and greater SOR (p<0.01) following eccentric exercise compared to low CK responders. Percent body fat was also higher in high responders compared to low responders (p=0.014). Peak CK activity was significantly correlated with MIS and SOR but no correlation with % body fat, muscle mass, and body mass index.

[Conclusion]

CK variability following eccentric exercise is closely related to MIS and SOR and % body fat may be a potent factor for CK variability.     

Effect of incubation temperature on muscle growth of barramundi Lates calcarifer at hatch and post-exogenous feeding

Muscle morphology was investigated in newly hatched barramundi Lates calcarifer larvae incubated at set temperatures (26, 29 and 31° C) prior to hatching. Three days after hatching (the start of exogenous feeding), larvae from the 26 and 31° C treatments were each divided into two groups and reared at that temperature or transferred over the period of several hours to 29° C (control temperature). Incubation temperature significantly affected muscle cellularity in the developing embryo, with larvae incubated at 26° C (mean ±s .e . 223·3 ± 7·9) having on average 14·4% more inner muscle fibres than those incubated at 31° C (195·2 ± 8·8) and 4·8% more than those incubated at 29° C (213·5 ± 4·7). Conversely, inner muscle fibre cross‐sectional area significantly increased at the warm incubation temperature in L. calcarifer, so that the total cross‐sectional muscle area was not different between treatment groups. The total cross‐sectional area of superficial muscle fibres and the proportion of superficial to total fibre cross‐sectional area in just hatched L. calcarifer were also affected by incubation temperature, with incubation at the cool temperature (26° C) increasing both the total cross‐sectional area and proportion of superficial muscle fibres. By 9 days post‐hatch, the aforementioned differences were no longer significant. Similarly, there was no difference in total superficial fibre cross‐sectional area between any treatment groups of L. calcarifer, whereas incubation temperature still significantly affected the proportion of superficial to total muscle fibre cross‐sectional area. Larvae hatched and grown at 31° C had a significantly reduced percentage of superficial muscle cross‐sectional area (mean ±s .e . 5·11 ± 0·66%) compared with those incubated and grown at 29° C (8·04 ± 0·77%) and 26° C (9·32 ± 0·56%) and those incubated at 26° C and transferred to 29° C (7·52 ± 0·53%), and incubated at 31° C and transferred to 29° C (6·28 ± 0·69%). These results indicate that changes in muscle cellularity induced by raising or lowering the incubation temperature of L. calcarifer display varying degrees of persistence over developmental time. The significance of these findings to the culture of L. calcarifer is discussed.