The aim of this study was to evaluate the effect of genetic variants on candidate genes corresponding to the sterol recognition element-binding protein-1 (SREBP-1) signaling pathway and stearoyl-CoA desaturases (SCD1 and SCD5) on muscle fatty acid (FA) composition of Brangus steers fattened on grass. FA profiles were measured on Longissimus lumborum muscle samples using a gas chromatography-flame ionization detection technique. A total of 43 tag single-nucleotide polymorphisms on the SCD1, SCD5, SREBP-1, SCAP, INSIG1, INSIG2, MBTPS1, MBTPS2, and SRPR genes were genotyped on 246 steers to perform a marker-trait association study. To evaluate the influence of the Indicine breed in the composite breed, additional groups of 48 Angus, 18 Hereford, 75 Hereford x Angus, and 36 Limousin x Hereford-Angus steers were also genotyped. To perform the association analysis, FA data were grouped according to the number of carbon atoms and/or number of double bonds (i.e. SFA, MUFA, PUFA, etc.). In addition, different indexes that reflect the activity of FA desaturase and elongase enzymes were calculated. SCD1 markers significantly affected C14:1/(C14:0 + C14:1) and C18:1/(C18:0 + C18:1) indexes, whereas one SNP in SCD5 was correlated with the C16:1/(C16:0 + C16:1) index. Polymorphisms in the signal recognition particle receptor (SRPR) gene were associated with all the estimated desaturase indexes. Because the evaluated markers showed no effect on total lipid content of beef, this work supports the potential utilization of these markers for the improvement of grass-fed beef without undesirable side effects.

Medicinal value has been attributed to Larrea divaricata CAV. (Zygophylaceae family) by the Indian tribes from South America. 1,2) In Argentina, Hieronymus 3) mentioned the medicinal properties of L. divaricata for a variety of diseases such as venereal disease, tuberculosis, colds, bowel cramps, rheumatism, and also as an antiseptic, expectorant, emetic and diuretic. 2-4) L. divaricata presents abundant flavonoids, 5) mainly quercetine and kaempferol, which are considered to be anticancerigenic agents. [6][7][8] The lignane nordihydroguaiaretic acid (NDGA), isolated from L. divatricata in 1945 by Waller and Gisvold,9) is considered to be a powerful inhibitor of lipoxygenase enzymes, which play an important role in cardiac diseases, asthma, arteriosclerosis, viral infections and cancer. [10][11][12][13][14][15][16] Plant cell culture represents a useful production alternative to direct extraction of valuable secondary metabolites from wild plants. The major advantages of tissue culture techniques over traditional cultivation of wild plants are: (a) useful compounds can be produced under controlled conditions, (b) plants are free of microbes and insects, (c) plants can easily be multiplied to yield specific metabolites, (d) a stable and uniform year-round supply of selected medicinal plants is guaranteed, independent of seasonal variations. [17][18][19][20][21] The aim of this work was to evaluate the conditions for in vitro regeneration of L. divaricata plants as an alternative technique for active compound production. MATERIALS AND METHODSPlant Material L. divaricata seed collection was carried out at Santa María de Punilla, "Sierras de Córdoba," located at 45 km north of Córdoba city, Argentina. This region has a temperate Mediterranean climate, with warm summers and dry winters (not excessively hard). The annual mean temperature is 16°C (the mean maximum and minimum temperatures being 34°C in January and 6°C in July, respectively), with an average annual rainfall of 550 mm. The location's average altitude is 700 m above sea level. 22) A voucher specimen was deposited in the International Herbarium of the National University of Río Cuarto, Argentina (RIOC).Germination Germination rates were assessed in different conditions: 1) control, 2) washing seeds overnight in running tap water, 3) scarification, 4) washing overnight in running tap waterϩscarification, 5) soaking overnight with 0.3 mM gibberellic acid (GA 3 ), 6) soaking overnight with 3 mM GA 3 , 7) soaking overnight with 15 mM GA 3 , 8) soaking overnight with 0.3 mM GA 3 ϩscarification, 9) soaking overnight with 3 mM GA 3 ϩscarification, 10) soaking overnight with 15 mM GA 3 ϩscarification.Seed surfaces were disinfected with ethanol 70% (v/v) for 10 min, followed by sodium hypochlorite 1.5% (v/v) for 15 min, and finally washed three times with sterile distilled water. Sterilized seeds were transferred to culture tubes containing 15 ml of agarized (0.8% w/v) half-strength MS 23) major and minor salt medium with 3% (w/v) sucrose, without plant growth regu...

ABSTRACT. The somatotropic axis is a major regulatory pathway of energy metabolism during postnatal growth in mammals. Genes involved in this pathway influence many economically important traits. The association of selected SNPs in these genes with carcass traits was examined in grazing Brangus steers. These traits included final live weight, ultrasound backfat thickness (UBFT), rib-eye area, kidney fat weight, hot carcass weight, and intramuscular fat percentage (%IMF). Genomic DNA (N = 246) was genotyped for a panel of 15 tag SNPs located in the growth hormone receptor (GHR), insulin-like growth factor I, insulin-like growth factor-binding protein 6, pro-melanin- Genetic markers of carcass traits in grazing Brangus steers concentrating hormone, suppressor of cytokine signaling 2, and signal transducer and activator of transcription 6 (STAT6) genes. Allelic and haplotype frequencies were compared with those of a sample of European breeds (N = 177 steers). Two tag SNPs in the GHR affected %IMF; one of them (ss86273136) was also strongly associated with UBFT (P < 0.003). The frequency of the most favorable GHR haplotype for %IMF was lower in Brangus steers. Moreover, the haplotype carrying two unfavorable alleles was present at a frequency of 31% in this group. Four tag SNPs on STAT6 had a significant effect on UBFT. One of these, SNP ss115492467, was also associated with %IMF. The STAT6 haplotype, including all the alleles favoring UBFT, was the most abundant variant (34%) in the European cattle, while it had a frequency of 14% in the Brangus steers. The four less favorable variants (absent in the European cattle) were found at a frequency of 38% in the Brangus steers. These results support the association of GHR and STAT6 SNP with carcass traits in composite breeds, such as Brangus, under grazing conditions.

<p>El cambio dinámico en el suelo debido a diferentes usos puede monitorearse mediante el seguimiento de variables sensibles. Para el contenido de fósforo (P), no existe un consenso acerca de la variable de medición más adecuada. En este trabajo se evaluó la utilidad de técnicas que miden disponibilidad, pérdida y capacidad de retención de P (P-Bray1, P-CaCl2, P75, ISP y GSP) para diferenciar cambios en el contenido de P del suelo, relacionados al uso de la tierra, así como la relación entre dichas técnicas. Se analizaron dos profundidades de suelo en dos sitios del sudeste de la provincia de Buenos Aires con diferentes secuencias: agrícolas (A), pastizales nativos (PN), sistemas forestales (FO) y pastizales secundarios (PS). Todas las técnicas pudieron diferenciar entre sistemas de manejo; con diferencias variables según la profundidad del suelo. Se detectaron correlaciones estrechas entre las técnicas, resultando dependientes del uso del suelo, P-Bray1 y P-CaCl2 (R2 = 0.89), P75 e ISP (R2 = 0,79) y GSPP75 o GSPISP con P-CaCl2 (R2 = 0.82 y 0.83 respectivamente). Los sistemas A incrementaron la disponibilidad de P (P-Bray1), disminuyeron la capacidad de retención (P75 e ISP) y generaron mayor riesgo de pérdidas de P (P-CaCl2). El FO y la PS presentaron mejor disponibilidad de P respecto de PN, con mayor capacidad de retención y con menores riesgos de pérdidas por escurrimiento. En base a los resultados, podría estimarse una forma de P en función de la determinación analítica de otra, pero de forma diferencial según el uso del suelo.</p>