Expression of MMP-1, -2, and -8 in longissimus dorsi muscle and their relationship with meat quality traits in cattle.

The extracellular matrix (ECM) is the major macromolecule in skeletal muscle, which affects meat quality greatly. The remodeling of the ECM is mainly regulated by matrix metalloproteinases (MMPs). The expression patterns of MMP-1, -2, and -8 in longissimus dorsi muscle were explored using quantitative real-time polymerase chain reaction. The results show that the expression of MMP-1, -2, and -8 decreased significantly from 135 days of pregnancy to postnatal 30 months. While the expression of MMP-1, -2, and -8 showed no significant relationships with intramuscular fat contents, MMP-1 and -2 showed significant negative correlations with the shearing force of the longissimus dorsi muscle in cattle. The expression of MMP-1 also showed a significant negative correlation with cooking loss and a positive correlation with water holding capacity. The expression levels of MMP-1 and -2 were usually higher in fat than in skeletal muscle tissue. The expression of MMP-8 was significantly higher in the mammary fat pad and the longissimus dorsi muscle than in all other tissues. This study indicates that the remodeling of the ECM has important effects both on the development of postnatal skeletal muscle and on meat quality.

Construction of a full-length cDNA library and preliminary analysis of expressed sequence tags from lymphocytes of half-pipe snowboarding athletes.

The genes of top athletes are a valuable genetic resource for the human race, and could be exploited to identify novel genes related to sports ability, as well as other functions. We analyzed the expressed sequence tags from top half-pipe snowboarding athletes using the SMART complementary DNA (cDNA) library construction method to elucidate the characteristics of the athlete genome and the differential expression of the genes it contains. Overall, we established a full-length cDNA library from the lymphocytes of half-pipe snowboarding athletes and analyzed the inserted gene fragments. We also classified those genes according to molecular function, biological characteristics, cellular composition, protein types, and signal paths. A total of 201 functional genes were noted, which were distributed in 27 pathways. TXN, MDH1, ARL1, ARPC3, ACTG1, and other genes measured in sequence may be associated with physical ability. This suggests that the SMART cDNA library constructed from the genetic material from top athletes is an effective tool for preserving genetic sports resources and providing genetic markers of physical ability for athlete selection.

Cigarette smoking among tuberculosis patients increases risk of transmission to child contacts.

SETTING: Observational cohort study in Lima, Peru. OBJECTIVE: To determine the association between exposure to a smoking tuberculosis (TB) case and latent tuberculous infection (LTBI). METHOD: Between September 2009 and August 2012, we identified 2132 patients with drug-susceptible TB and their 2054 child household contacts. Data were collected on active and secondhand smoking status and other risk factors for infection specific to the index case, the household and the exposed contacts. Contacts underwent a tuberculin skin test (TST) to determine their tuberculous infection status at baseline, 6-month and 12-month follow-up. We estimated the association between exposure to a smoking index case and LTBI using a modified Poisson regression model. RESULTS: The 21 children (age â©¿15 years) exposed to smoking index TB patients were more likely to be TST-positive at baseline (RR 2.64, 95%CI 1.78-3.91), by 6 months (RR 1.91, 95%CI 1.40-2.60) and by 12 months (RR 1.48, 95%CI 1.07-2.06), than those who were not exposed. TST positivity among children at these time points did not vary with secondhand smoke exposure. CONCLUSIONS: TB patients who smoke may be more likely to transmit infection to their contacts. Interventions designed to reduce smoking among TB patients may minimise further spread of the disease.

Male infertility in Northeast China: molecular detection of Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome.

The prevalence of microdeletions of azoospermia factor (AZF) among azoospermic Klinefelter's syndrome (KFS) patients shows conflicting data. We aimed to detect this frequency in a Northeast Chinese population, and to investigate the possible association between AZF microdeletions and KFS by comparison with previous conflicting reports. Eighty men affected with KFS and a random healthy control group comprising 60 fertile men and women were recruited. AZF microdeletions were detected by multiplex polymerase chain reaction using 9 specific sequence-tagged sites. Karyotype analyses were performed on peripheral blood lymphocytes using standard G-banding. Finally, azoospermia was confirmed in 77 men affected with KFS and no AZF microdeletions were found. Karyotype analysis revealed 1 patient with karyotype 47,XXY,inv (9) (p11, q13), and 2 with mosaic karyotypes (46,XX/47,XXY and 46,XY/47,XXY). All other patients had karyotype 47,XXY. Review of the literature showed that these results were similar to those of other regions of Northeast Asia, but differed from those obtained from Caucasian populations. Our results supported the proposal that AZF microdeletions and KFS result from separate genetic defects. The prevalence of AZF in azoospermic KFS patients varies among populations, and it might result from genetic drift or selective pressure. These results suggest that routine screening for classical AZF microdeletions among infertile azoospermic men with a 47,XXY karyotype might not be necessary in Northeast Chinese individuals. However, it remains imperative for patients considering assisted reproductive treatments, particularly for those with mosaic karyotypes.

Novel splice variants of the bovine PCK1 gene.

Phosphoenolpyruvate carboxykinase 1 (PCK1), also named PEPCK-C, is a multiple-function gene that is involved in gluconeogenesis, glyceroneogenesis, reproduction, female fertility, and development of obesity and diabetes. How its many functions are regulated was largely unknown. Therefore, we investigated mRNA expression and possible splice variants of PCK1 by screening cDNA in nine tissues from Holstein bulls and cows. PCK1 mRNA was highly expressed in the liver, kidney, ovary and testis; expression levels were low in the heart, spleen, and lung tissues. Expression of this gene was not detected in skeletal muscle. This led to the discovery of five novel bovine splice variants, named PCK1-AS1-PCK1-AS5. In PCK1-AS1, 51 nucleotides in the interior of exon 2 were spliced out. In PCK1-AS2, exons 2 and 3 were altered by the alternative 3' and 5' splice sites, respectively. PCK1-AS3 was truncated from the 3' end of exon 2 to the 5' end of exon 4. In PCK1-AS4, exon 5 was completely spliced out. In PCK1-AS5, exons 5 and 6 and the 5' end of exon 7 were spliced out. These splice variants (PCK1-AS1-PCK1-AS5) potentially encoded shorter proteins (605, 546, 373, 246 and 274 amino acids, respectively), when compared to the complete protein (622 amino acids). Considering the functional domains of the PCK1 protein, it is likely that these splice variants considerably affect the function of this protein; alternative splicing could be one of the mechanisms by which the diverse functions of PCK1 are regulated.