Age-related changes in albumin and actin of human myocardium

Proteomic technologies revealed products of 2 genes (α-actin and albumin) in a human myocardium tissue. They exist as fragments and their appearance and increased content correlated with age. The age-related variants differ from the mature forms of these proteins by the absence of N-terminal fragments of the amino acid sequences. In the chronic ischemic heart disease (CIHD), these age-related proteins were found in 50% of cases (in the age group 31–40 years), whereas in the control group such combination was detected only in 10% of the examined individuals. Subsequent studies in this field would probably reveal molecular mechanisms responsible for impairment and/or ageing of the myocardium and also of adaptation/disadaptation mechanisms in the CIHD.     

猫小脑髓质胶质反应的年龄相关性变化

探讨青年猫和老年猫小脑髓质中胶质反应的年龄相关性变化及其意义。用改良的Holzer结晶紫染色显示所有胶质细胞,GFAP(胶质纤维酸性蛋白)免疫染色显示星形胶质细胞。光镜下对青年猫与老年猫小脑髓质中胶质细胞和GFAP免疫阳性(GFAP-IR)星形胶质细胞进行形态学观察和定量研究。与青年猫比较,老年猫小脑髓质中胶质细胞和GFAP-IR细胞密度均显著增加(P<0.01),胞体较大;GFAP阳性细胞阳性反应较强,突起稠密;星形胶质细胞占胶质细胞总数比例增加。这表明小脑髓质中胶质细胞随年龄增长明显增生,尤其星形胶质细胞具有明显的年龄相关性活动增强。提示胶质细胞及星形胶质细胞的增生可能对衰老的神经纤维起保护作用;星形胶质细胞对衰老较敏感。     

猪CFL2b基因在成肌细胞中的表达及对肌球蛋白重链基因表达的影响

猪CFL2b基因主要在骨骼肌中表达,对肌肉的发育和肌纤维的形成具有一定作用。为了解猪CFL2b基因与肌纤维性状的相关性,利用定向克隆和基因转染技术获得能稳定表达猪CFL2b基因的成肌细胞株,荧光显微镜观察及Western Blotting检测CFL2b基因在成肌细胞中的表达;应用实时定量PCR技术对细胞内肌球蛋白重链基因（MyHC）的表达变化进行检测。结果显示：CFL2b基因对MyHC的表达有明显影响,其中MyHC2x基因和MyHC26基因的表达明显上调,MyHCl／slow的表达变化不明显。表明CFL2b基因与猪的肌纤维性状密切相关,推测猪CFL2b基因的高表达可能导致猪的不良肉质性状,可以考虑将CFL2b基因作为猪肉质性状的候选基因[动物学报54（6）：1014—1019,2008]。     

Effects of active immunization against porcine Sox6 on meat quality and myosin heavy chain isoform expression in growing-finishing pigs

A feeding trial for 91 days was conducted to investigate effects of active immunization against porcine Sox6 (pSox6) on meat quality and myosin heavy chain (MyHC) isoform expression in growing-finishing pigs. Twenty-four castrated Duroc?×?Landrace?×?Yarkshire pigs were randomly divided into three groups: (1) Control group; (2) 1?mg/head pSox6 active immunity group; (3) 4?mg/head pSox6 active immunity group (4?mg/head group). The results showed that pigs in 4?mg/head group had a greater a* (Redness) and a higher marbling score, while no significant effect was observed in L* (Lightness), b* (Yellowness), intramuscular fat and cooking loss. Muscle succinic dehydrogenase activity in pSox6 active immunization groups was significantly increased, and muscle lactate dehydrogenase activity was significantly reduced. Meanwhile, active immunization against pSox6 upregulated the mRNA expression of MyHC I, while no effect was observed on the mRNA expressions of MyHC IIa, MyHC IIx, MyHC IIb. In addition, pigs in the 4?mg/head group exhibited lower Sox6 mRNA level and higher MyHC I protein level, while no significant influence was observed on MyHC IIb protein level. Together, our data imply that active immunization against pSox6 could improve the pork quality and promote the MyHC I expression in growing-finishing pigs.     

Venom gland of the ichneumonid Diadromus collaris： morphology, ultrastructure and age-related changes

Females of the solitary parasitoid Diadromus collaris （Insecta： Hymenoptera： Ichneumonidae） lay eggs in the pupae of Plutella xylostella （Lepidoptera： Plutellidae）, and the venom is synchronously injected into hosts. The venom apparatus consists of two glandular tubules terminating in a common reservoir, A ductule connects the reservoir with the sting apparatus, by which the reservoir content enters the latter. Secretory units line the two glandular tubules. All secretory cells belong to dermal gland type Ⅲ. Dermal gland cells in glandular tubules are more abundant and developed than those in the reservoir. There are extensive rough endoplasmic reticulum and electrondense vesicles, and the microvilli are well developed. By the cuticle-lined central funnel secretion products of secretory units reach the reservoir. Moreover, the secretory apparatus undergoes age-related changes. The secretory units in the venom gland are better developed and more vigorous 7 days after eclosion than those 1 day after eclosion; autolytic processes occur 15 days after eclosion, and the tissue of the reservoir is more prostrate 15 day after eclosion than those 1 day after eclosion. The ovipostion peak of this parasitoid, about 3-7 days after eclosion, corresponds with the period when the venom gland is highly developed in the life span of the wasp.     

Age-related changes in foraging in the German cockroach (Dictyoptera: Blattellidae)

The dynamics of exploitation of standard experimental food sources by the German cockroach, Blattella germanicaL. (Blattellidae), were analyzed in an urban habitat in relation to developmental stage. The data presented here stress differences in foraging capacities between small (first-and second-instar) larvae and animals of other developmental stages. The first animals to arrive in a food patch presented a developmental-stage distribution significantly different from that of the general population. Adults and large larvae (fifth and sixth instars) were the first to find food sources and, in particular, before small larvae. Significant differences appeared between developmental stages concerning givingup time and the time animals left a patch. Small larvae were significantly underrepresented in a patch just before food exhaustion but they were significantly more numerous than expected just after depletion. Small larvae remained in the vicinity of a depleted food dish longer than animals of other developmental stages. Adults left patches as soon as these were depleted, long before small larvae did. Developmental stage influenced rate of departure. These observations indicate that cockroaches improve their foraging performance as they grow larger.     

Repression of slow myosin heavy chain 2 gene expression in fast skeletal muscle fibers by muscarinic acetylcholine receptor and G(alpha)q signaling

Gene expression in skeletal muscle fibers is regulated by innervation and intrinsic fiber properties. To determine the mechanism of repression of slow MyHC2 expression in innervated fast pectoralis major (PM) fibers, we investigated the function of the muscarinic acetylcholine receptor (mAchR) and G(alpha)q. Both mAchR and G(alpha)q are abundant in medial adductor (MA) and PM fibers, and mAchR and G(alpha)q interact in these fibers. Whereas innervation of PM fibers was insufficient to induce slow MyHC2 expression, inhibition of mAchR activity with atropine in innervated PM fibers induced slow MyHC2 expression. Increased G(alpha)q activity repressed slow MyHC2 expression to nondetectable levels in innervated MA fibers. Reduced mAchR activity decreased PKC activity in PM fibers, and increased G(alpha)q activity increased PKC activity in PM and MA fibers. Decreased PKC activity in atropine-treated innervated PM fibers correlated with slow MyHC2 expression. These data suggest that slow MyHC2 repression in innervated fast PM fibers is mediated by cell signaling involving mAchRs, G(alpha)q, and PKC.     

Influence of α-tocopherol supplementation on trans-18:1 and conjugated linoleic acid profiles in beef from steers fed a barley-based diet

The current study was conducted to determine the effect of different α-tocopherol (vitamin E) inclusion levels on trans(t)-18:1 and conjugated linoleic acid (CLA) profiles in subcutaneous and intramuscular fat of steers fed a barley-based diet. Fifty-six feedlot steers were offered a barley-based finisher diet (73% steam rolled barley, 22% barley silage and 5% supplement as-fed basis) with four levels of supplementary dl-α-tocopheryl acetate (340, 690, 1040 or 1740 IU/steer per day) for 120 days. Adding vitamin E to the diet had little effect on the overall fatty acid composition of intramuscular fat. The proportion of individual and total t,t- and cis(c),t-CLA, n-3 fatty acids, total polyunsaturated fatty acids (PUFA), mono-unsaturated fatty acids and saturated fatty acids to PUFA ratio in subcutaneous fat were not influenced (P > 0.05) by dietary vitamin E supplementation. Increasing levels of vitamin E led to linear reductions in t6-/t7-/t8-18:1 and t10-18:1 (P < 0.05), and linear increase in t11-/t10-18:1 ratio (P < 0.05) in subcutaneous fat. The content of 20:3n-6 and total n-6 in subcutaneous fat decreased (P < 0.05) linearly with increasing amounts of vitamin E. The subcutaneous fat n-6:n-3 ratio showed a quadratic (P < 0.05) response to vitamin E. In conclusion, although vitamin E supplementation has some potential to reduce t10-18:1 formation and increase t11-/t10-18:1 ratio in subcutaneous fat of cattle fed barley-based diets, the changes in the present study were limited and may not have been sufficient to impact on human health.     

FoxO1抑制猪骨骼肌MyHC Ⅰ的表达

为研究FoxO1与骨骼肌纤维类型之间的关系,本试验以大白猪为实验材料,利用RT-PCR和Western印迹技术,检测了FoxO1与肌纤维类型标志基因MyHCⅠ、MyHCⅡa、MyHCⅡb和MyHCⅡx在特定骨骼肌中的表达规律,以及调控肌纤维类型关键基因Mef2c和NFAT的表达,并用Wortmannin处理原代培养的猪骨骼肌成肌细胞,检测了FoxO1与肌纤维类型相关基因的表达.结果显示,FoxO1在不同骨骼肌类型中mRNA表达差异不显著(P0.05),其蛋白表达与MyHC各亚型显著相关.Wortmannin处理结果显示,在处理的第3和5d,FoxO1蛋白与MyHCⅡb,MyHCⅡx和NFAT表达显著正相关,而与MyHCⅠ,MyHCⅡa和Mef2c表达显著负相关.结果表明,FoxO1通过抑制MyHCⅠ的表达调控肌纤维类型.     

The Effect of Passive Movement on Denervated Soleus Highlights a Differential Nerve Control on SERCA and MyHC Isoforms

The sarco-endoplasmic reticulum Ca²⁺ ATP-ase (SERCA) and myosin heavy chain (MyHC) levels were measured in hindlimb-denervated and selectively denervated rat soleus muscles. Selective denervation allowed passive movement of the soleus, whereas hindlimb denervation rendered it to passivity. To minimize chronic effects, we followed the changes only for 2 weeks. Selective denervation resulted in less muscle atrophy, a faster slow-to-fast transition of MyHC isoforms, and less coordinated expressions of the slow vs fast isoforms of MyHC and SERCA. Generally, expression of the slow-twitch type SERCA2a was found to be less dependent, whereas the slow-twitch type MyHC1 was the most dependent on innervation. Our study shows that passive movement is able to ameliorate denervation-induced atrophy of the soleus and that it also accentuates the dyscoordination in the expression of the corresponding slow and fast isoforms of MyHC and SERCA. (J Histochem Cytochem 56:1013–1022, 2008)