Muscle transcriptomic analyses in Angus cattle with divergent tenderness

Beef tenderness contributes significantly to variation of beef palatability, and is largely influenced by various genetic and environmental factors. To identify candidate genes and pathways related to beef tenderness, we analyzed the longissimus dorsi (LD) muscle of Angus cattle that had different degrees of tenderness, measured by Warner-Bratzler shear force (WBSF). Microarray and RT-PCR analyses identified 53 genes that were differentially expressed in LD samples categorized as either tough or tender, including myosin, heavy chain 3 skeletal muscle embryonic (MYH3), myosin heavy chain 8 skeletal muscle perinatal (MYH8), guanylate binding protein 5 (GBP5), fatty acid binding protein 4 (FABP4), Stearoyl-coenzyme A desaturase (SCD), Fatty acid synthase (FASN), ubiquitin-like with PHD and ring finger domains 1 (UHRF1). Most of these genes are involved in lipid metabolism and skeletal muscle contraction. Employing Gene ontology (GO) and Ingenuity Pathway Analysis (IPA), several GO terms and pathways were found to be related to hydrolase, peptidase and GTPase activity, lipid metabolism, small molecule biochemistry, molecular transport, and tissue development. Overall, this analysis provides insight into the metabolic relationships between muscle biology and beef quality.     

DNA-Protein Complex in Circular DNA from Phage ϕ29

THE DNA of the B. subtilis phage ?29 has been described as unpermuted linear duplex molecules¹ of molecular weight 11 × 10⁶, but the formation of circular molecules has also been indicated, suggesting the existence of cohesive ends^1,2.     

Structure and polymorphic map of human lipoprotein lipase gene

Lipoprotein lipase (LPL) catalyzes the key step for the removal of triacylglycerol-rich lipoproteins from the circulation. In this paper, we report the cloning and structure of the normal human LPL gene, which was isolated in three overlapping lambda phage clones that span about 35 kilo bases (kb) of the genetic locus. The peptide coding region of the gene is approx. 23 kb in length and contains nine exons with intron sizes ranging from 0.7 to 8.7 kb. The entire 3' untranslated region is in the tenth exon. Specific sequences in this region support the hypothesis that two mRNA species found for human LPL are generated by differential utilization of polyadenylation signals. The first exon occurs in the 5' untranslated region and the region coding for the signal peptide. The second exon includes the protein domain coding for the N-linked glycosylation site that is required for the expression of enzyme activity. The fourth exon contains the region that was proposed as a lipid binding domain, the sixth for one putative heparin binding domain, and the eighth codes for a domain containing another N-linked glycosylation site. These results suggest that the unique structural and functional domains are confined to specific exons. The PvuII polymorphic site was located within the intron between exon 6 and 7 and the HindIII polymorphic site to the 3' flanking region. The location of these polymorphic sites suggests that the PvuII restriction fragment length polymorphism (RFLP) associated with lipase deficiency in a few Japanese kindred may be a linkage marker for a functional defect of LPL, while the HindIII RFLP associated with hypertriglyceridemia may be important for gene regulation of LPL.     

两个苜蓿品种营养器官解剖结构特征比较

为了明确具有极强抗虫特性的‘草原4号紫花苜蓿’(Medicago sativa L.‘Caoyuan No.4’) 营养器官的解剖特征,该研究选择具有抗蓟马特性较强的‘草原2号杂花苜蓿’(Medicago varia Martin.‘Caoyuan No.2’)为对照,采用显微镜观察比较两品种的根、茎、叶解剖结构特征,为揭示‘草原4号紫花苜蓿’ 抗蓟马特性提供理论依据。结果显示：(1)‘草原4号紫花苜蓿’根部解剖结构的皮层薄壁细胞厚度、内皮层厚度、形成层厚度、木质部厚度和木射线宽度等5个指标均极显著高于(P＜0.01)‘草原2号杂花苜蓿’,其中木射线宽度(159.37 μm)是‘草原2号杂花苜蓿’的1.82倍。(2)‘草原4号紫花苜蓿’的茎部厚角组织厚度(21.4 μm)极显著高于‘草原2号杂花苜蓿’(P＜0.01),而韧皮部宽度、髓直径却均极显著低于‘草原2号杂花苜蓿’(P＜0.01)。(3)‘草原4号紫花苜蓿’叶片解剖构造的7个指标均极显著高于‘草原2号杂花苜蓿’(P＜0.01),其中栅栏组织层数(2～3层)极明显地高于‘草原2号杂花苜蓿’(1~2层)。研究表明,‘草原4号紫花苜蓿’的组织结构特征具有明显的抗虫特征,且其组织的抗虫特征比‘草原2号杂花苜蓿’更为突出。     

Assembly of the sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures: localization by immunofluorescence of sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures

Immunofluorescent staining techniques were used to study the distribution of the Ca(2) + Mg(2+)-dependent ATPase and calsequestrin in primary cultures of differentiating rat skeletal muscle cells, grown for different periods of time under various culture conditions. In mononucleated myoblasts calsequestrin was detected after 45 h in culture whereas the ATPase was not detected until 60 h. After cell fusion began, both proteins could be identified in all multinucleated cells. Myoblasts grown for longer than 60 h in low Ca(2+) medium contained calsequestrin and the ATPase, even though they were unable to fuse. These studies at the cellular level confirm biochemical findings on the biosynthesis of calsequestrin and the ATPase. Immunofluorescent staining of myoblasts showed that calsequestrin first appears in a well-defined region of the cell near one end of the nucleus. At later times, the staining occupied progressively larger regions adjacent to the nucleus and took on a fibrous appearance. This suggests that calsequestrin first accumulates in the Golgi region and then gradually spreads throughout the cell. In contrast, the ATPase appeared to be concentrated in many small patches or foci throughout the cytoplasm and was never confined to one particular region, although some parts of the cell often stained more intensely than others. In multinucleated cells, alternating dark and fluorescent strands parallel to the longitudinal axis of the cells were evident.     

Production of an enzymatically inactive analog of phospholipase D from Corynebacterium pseudotuberculosis.

The gene pld, encoding the phospholipase D (PLD) of Corynebacterium pseudotuberculosis, was mutagenized using formic acid and then expressed in Escherichia coli. Mutagenesis was targeted at the coding region of pld, so as to produce only one or a limited number of point mutations. Transformants were screened for the enzymatic and immunological properties of their PLD products. One clone was found to produce a protein which was enzymatically inactive, but which was comparable to the wild-type PLD in size and antigenicity. The sequence of the pld mutant revealed a single base change. As a consequence, the codon for His20 was converted to Tyr. These results suggest that His20 forms part of the active site of the PLD molecule. If this protein is immunogenic in sheep, it would form the basis of a genetically inactivated vaccine.