Copy number variation and missense mutations of the agouti signaling protein (ASIP) gene in goat breeds with different coat colors

In goats, classical genetic studies reported a large number of alleles at the Agouti locus with effects on coat color and pattern distribution. From these early studies, the dominant A(Wt) (white/tan) allele was suggested to cause the white color of the Saanen breed. Here, we sequenced the coding region of the goat ASIP gene in 6 goat breeds (Girgentana, Maltese, Derivata di Siria, Murciano-Granadina, Camosciata delle Alpi, and Saanen), with different coat colors and patterns. Five single nucleotide polymorphisms (SNPs) were identified, 3 of which caused missense mutations in conserved positions of the cysteine-rich carboxy-terminal domain of the protein (p.Ala96Gly, p.Cys126Gly, and p.Val128Gly). Allele and genotype frequencies suggested that these mutations are not associated or not completely associated with coat color in the investigated goat breeds. Moreover, genotyping and sequencing results, deviation from Hardy-Weinberg equilibrium, as well as allele copy number evaluation from semiquantitative fluorescent multiplex PCR, indicated the presence of copy number variation (CNV) in all investigated breeds. To confirm the presence of CNV and evaluate its extension, we applied a bovine-goat cross-species array comparative genome hybridization (aCGH) experiment using a custom tiling array based on bovine chromosome 13. aCGH results obtained for 8 goat DNA samples confirmed the presence of CNV affecting a region of less that 100 kb including the ASIP and AHCY genes. In Girgentana and Saanen breeds, this CNV might cause the A(Wt) allele, as already suggested for a similar structural mutation in sheep affecting the ASIP and AHCY genes, providing evidence for a recurrent interspecies CNV. However, other mechanisms may also be involved in determining coat color in these 2 breeds.

Localization in the frontal plane is not susceptible to manipulation of afferent feedback via the Jendrassik Maneuver

We have previously shown that registered vergence eye position is altered while participants perform the Jendrassik Maneuver (JM). We proposed that the altered eye position signal registration is due to the effect of the JM which changes the gain of the sensory feedback from the eye muscles, possibly via the activity of non-twitch motoneurons. We conducted two studies to further extend and clarify one of our previous findings by examining whether the JM also affects registered eye position during localization in the frontal plane. Since the non-twitch motoneurons do not receive premotor input from areas involved in the programming of saccades, we hypothesized that localization responses associated with the saccadic system should not be affected by the JM. The data confirmed our prediction. We propose that the non-twitch motoneurons are involved in parametric adjustment of the proprioceptive feedback loops of the vergence but not the version eye movements.

Manipulation of extraocular muscle afference has no effect on higher order perceptual judgments

Observers perceive targets as farther while performing the Jendrassik Maneuver (JM) suggesting that eye position is registered as more divergent. We examined the effects of the JM perturbation in three studies of perceptual judgment that rely on accurate registration of absolute distance: size constancy, stereoscopic depth, and the magnitude of the Pulfrich illusion. The data showed no significant differences between the JM and control conditions. The lack of an effect may be due to the fact that vergence is not a perfect cue to distance. Furthermore, the relative contribution of extraocular muscle afference to registered eye position may be less significant for higher order perceptual judgments.

[Absorption of fat from three dietary sources in rats with lactose induced diarrhea]

Low energy intake is one the most important factors related to nutritional wasting during diarrheal episodes and fat is the macronutrient with the highest energy value. So we intended to seek dietary fat sources, with the highest bioavailability during diarrheal episodes. Three basal (control) and three 42.8% lactose containing diets, used to induce diarrhea, were prepared with corn oil, butterfat or lard. The assay included 48 Sprague-Dawley rats, 28 d of age, initial weights of 65.5 +/- 5.2 g, distributed in 6 groups that received the diets during 15 d. The different types of fat did not affect diet intake, weight gain or fecal losses in rats without diarrhea (control). Low weight gain was found in rats with diarrhea regardless of the type of fat consumed and was related to low diet consumption. Mean fat absorption during diarrhea was as follows: butterfat 84%, lard 87% and corn oil 91%. The latter was related to lower fecal losses and higher fat absorption during the 15 d study. Considering that the three fat sources evaluated are easily purchased and widely accepted, and that nutritional management of subjects with diarrhea includes the intake of energy dense diets, it seems that the use of corn oil in these formulations could offer greater advantages.

Egocentric localization: visually directed alignment to projected head landmarks in binocular and monocular observers

PURPOSE

To determine the accuracy and precision with which humans align moving, non-moving, point-like and linear stimuli to three head landmarks projected to a frontal plane. Monocularly enucleated and binocularly normal subjects, performing monocularly, were tested.

METHODS

Experimental tasks consisted of aligning the stimulus, a luminescent target, using a remote steering wheel control, to three projected landmarks; the nose, and the outside edge of each ear. Experiments were performed with a fixed [static] linear stimulus and a small dynamic stimulus, and then with a fixed stimulus at both a very close and an intermediate distance.

RESULTS

The data from the monocular enucleated observers showed better accuracy in some conditions but their variable errors were larger than those of the controls.

CONCLUSIONS

We propose that, for the alignments of the enucleated monocular subjects, a) the increase in accuracy is consistent with a shift of the egocenter in the direction of the remaining eye, and b) the decrease in precision may be due to the fact that the egocenter does not correspond to the mid-sagittal or median plane. This disparity would require adjustments to be learned in order to perform tasks involving visually directed alignments to the self.

Microbial sensor for new-generation cephalosporins based in a protein-engineered beta-lactamase

A protein-engineered beta-lactamase, constructed by site-directed mutagenesis in Escherichia coli (E104M/G238S), and having broadened specificity, was able to degrade cephalosporins of first, second, and third generations. Manipulations of culture conditions allowed an increase in beta-lactamase specific activity by up to twofold. The resultant bacteria were used to construct an immersable whole-cell biosensor for the detection of new-generation cephalosporins. Cells were immobilized on agar membranes, which in turn were attached to the surface of a flat pH electrode, thus constituting a biosensor based on the detection of pH changes. The sensor was able to detect second- and third-generation cephalosporins: cefamandole (0.4-4 mM), cefotaxime (0.4-3.5 mM), and cefoperazone (0.3-1.85 mM). Response times were between 3.5 and 11 min, depending on the kind of cephalosporin tested. The biosensor was stable for at least 7 d, time during which up to 100 tests were performed.