Felipe A. Rodríguez-Almeida

Effect of repeated suboptimal chlorate treatment on ruminal and fecal bacterial diversity.

The minimal effective dose of sodium chlorate as an intervention to reduce the carriage of pathogenic bacteria in food-producing animals has not been clearly established. The effect of low-level oral chlorate administration to ewes was assessed by comparing the diversity of prominent bacterial populations in their gastrointestinal tract. Twelve lactating crossed Pelibuey and Blackbelly-Dorper ewes (average body weight, 65 kg) were randomly assigned (four per treatment) to receive a control treatment (TC; consisting of 3 g of NaCl per animal per day) or one of two chlorate treatments (T3 or T9; consisting of 1.8 or 5.4 g of NaClO3 per animal per day, respectively). Treatments were administered twice daily via oral gavage for 5 days. Ruminal and fecal samples were collected daily, starting 3 days before and ending 6 days after treatment, and were subjected to denaturing gradient gel electrophoresis of the 16S rRNA gene sequence amplified from total population DNA. For ruminal microbes, percent similarity coefficients (SCs) between groups varied from 23.0 to 67.5% and from 39.4 to 43.3% during pretreatment and treatment periods, respectively. During the treatment period, SCs within groups ranged from 39.4 to 90.3%, 43.3 to 86.7%, and 67.5 to 92.4% for TC, T3, and T9, respectively. For fecal microbes, SCs between groups varied from 38.0 to 85.2% and 38.0 to 94.2% during pretreatment and treatment periods, respectively. SCs for fecal populations during treatment were most varied for TC (38.0 to 67.9%), intermediate for T9 (75.6 to 92.0%), and least varied for T3 (80.6 to 90.6%). Heterogeneity within and between groups provided no evidence of an effect of chlorate treatment on ruminal or fecal microbial populations.

Genome Sequence of Citrobacter sp. CtB7.12, Isolated from the Gut of the Desert Subterranean Termite Heterotermes aureus

ABSTRACT The draft genome of Citrobacter sp. CtB7.12, isolated from termite gut, is presented here. This organism has been reported as a cellulolytic bacterium, which is biotechnologically important because it can be used as a gene donor for the ethanol and biofuel industries.

Dicer gene expression during early bovine embryo development.

The transition from oocyte to embryo involves deactivation of the oocyte’s genome and activation of the embryo’s genome. During this process, maternal mRNAs stored during oogenesis are selectively degraded by microRNAs generated by a Dicer ribonuclease (Tang et al., 2007). The objective of this study was to evaluate Dicer gene expression in early bovine embryo development. For these studies, cumulus--oocyte complexes (COCs) were aspirated from antral follicles obtained from cow ovaries collected at a slaughterhouse. Immature oocytes were then extracted and subjected to maturation for in vitro fertilization. Using the Arcturus PicoPure extraction kit, total RNA was obtained from three independent samples of immature oocytes, oocytes matured for 24 hr, embryos of 2-, 4-, 8-, and 16-cell embryos, morulae, and blastocysts collected 32, 44, 90, 105, 120, and 168 hr post-fertilization. From each sample, 10 ng total RNA were used to synthesize cDNA, from which 1ml was used to amplify Dicer [(F)5 -CTGGTGTGCCGATAAAG3, (R)5 -GTTCCGAGGCTGATTCT3] and Histone H2A [(F)5 CAGCAAGGGACAACAA3, (R)5 -TCCTCTTTTCTCTGGG3] mRNAs. Amplification of the maternal gene, Mater [(F)5 -ACCTGGATTTGGTGAACTGC3, (R)5 -TCCAGCAGCCTTCTTACTCG3], was also performed as a control of maternal gene expression. Gene expression values were obtained using gel band optical densitometry (Fig. 1A) by ImageJ software (http:// rsbweb.nih.gov/ij/index.html), and values for Dicer and Mater were normalized to Histone H2A. An analysis of variance was performed using the GLM procedure of SAS while means separation was analyzed by Tukey’s test. An increase in Dicer expression was detected in the mature oocytes sampled (P< 0.05), implying that gene repression occurs during meiosis II. Expression of Dicer remained unchanged in embryos ranging from 2 to 8 cells, but decreased in embryos with 16 cells (P< 0.05). These results indicate that Dicer expression is repressed during activation of the embryonic genome, which is characteristic of a maternal gene (Fig. 1C). Correspondingly, when the embryonic genome was activated, expression of Dicer increased during the morula stage (P< 0.05), consistent with an induction of genetic reprogramming by the new organism (Fig. 1B). During the process of meiotic maturation, the oocyte is transcriptionally inactive until fertilization occurs. The transition from oocyte to embryo then involves the degradation of different maternal mRNAs stored during oogenesis, with the process involving the ribonuclease Dicer. Consistent with this, murine oocytes lacking Dicer are unable to complete meiosis due to defects in meiotic spindle organization and chromosome congression (Murchison et al., 2007; Liu et al., 2010). Here we find that bovine oocytes and embryos exhibited similar expression profiles for Dicer. Our results suggest that the bovine form of Dicer also plays an important role in meiotic processes during oocyte maturation, thereby identifying a role for Dicer in embryonic development and advancing our understanding of the reproductive processes in bovine.

Draft Genome Sequences for Five Strains of Trabulsiella odontotermitis, Isolated from Heterotermes sp. Termite Gut

ABSTRACT Trabulsiella odontotermitis represents a novel species in the genus Trabulsiella with no complete genome reported yet. Here, we describe the draft genome sequences of five isolates from termites present in the north of Mexico, which have an interesting pool of genes related to cellulose degradation with biotechnological application.

Effects of repeated-low level sodium chlorate administration on ruminal and fecal coliforms in sheep

Abstract The objective of this study was to evaluate the efficacy of oral sodium chlorate administration on reducing total coliform populations in ewes. A 30% sodium chlorate product or a sodium chloride placebo was administered to twelve lactating Dorper X Blackbelly or Pelibuey crossbred ewes averaging 65 kg body weight. The ewes were adapted to diet and management. Ewes were randomly assigned (4/treatment) to one of three treatments which were administered twice daily by oral gavage for five consecutive days: a control (TC) consisting of 3 g sodium chloride/animal/d, a T3 treatment consisting of 1.8 g of sodium chlorate/animal/d, and a T9 treatment consisting of 5.4 g sodium chlorate/animal/d; the latter was intended to approximate a lowest known effective dose. Ruminal samples collected by stomach tube and freshly voided fecal samples were collected daily beginning 3 days before treatment initiation and for 6 days thereafter. Contents were cultured quantitatively to enumerate total coliforms. There were no significant differences in total coliform numbers (log10 cfu/g) in the feces between treatments (P = 0.832). There were differences (P < 0.02) in ruminal coliform counts (log10 cfu/mL) between treatments (4.1, 4.3 and 5.0 log10/mL contents in TC, T3 and T9 Treatments, respectively) which tended to increase from the beginning of treatment until the 5th day of treatment (P < 0.05). Overall, we did not obtain the expected results with oral administration of sodium chloride at the applied doses. By comparing the trends in coliform populations in the rumen contents in all treatments, there was an increase over the days. The opposite trend occurred in the feces, due mainly to differences among rumen contents and feces in ewes administered the T9 treatment (P = 0.06). These results suggest that the low chlorate doses used here were suboptimal for the control of coliforms in the gastrointestinal tract of ewes.

Consanguinidad y estimación de parámetros genéticos para morfología del caballo Lusitano en México

The Lusitano horse breeders association in Mexico proposed the development of genetic evaluation for morphological traits (VM: head-neck (CC), withers (CR), chest (PC), back and loin (DR) and croup (GR)) considered in the selection criteria; however, in earlier studies found high levels of inbreeding (F; 6,6 % average), with constant trend. The objectives were to analyze the effects of F through three indicators (IDF: F of animal (IF); average correlation coefficient (CRP); and, change rate of F (DF)) on the average performance, the estimate of heritability (h2) and genetic correlation (rg) for the VM. Including alternately the IDF as covariate of first order were performed four univariate analysis (UNV) for each VM, and four multivariate analyses with the five VM. The covariate solutions of IDF were equal to zero (p>0,05). The h2 with the UNV ranged from 0,08 (DR) to 0,30 (CC), the general average was 0,18. The maximum change with IDF was 0,01. In the MUV, the h2 ranged from 0,11 to 0,35, the general average was 0,198; in the rg, the average without IDF was 0,53, in the interval of 0,01 to 0,97; with IDF the average was 0,59, with estimates above 0,20. The h2 of UNV vs. MUV without IDF were similar. For PC and GR the h2 decreased 0,03 of UNV to MUV with IDF; to contrast of CC, CR y DR with increments of 0,06. Inside MUV, for CC, CR and DR the h2 increased with IDF, with more effect CRP; however, in PC and GR decreased, with more effect of F.