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J A Arias

Publications and source records attributed to J A Arias.

12 recordsLinked to original sources
PubMed2004

Identification of an ovulation rate QTL in cattle on BTA14 using selective DNA pooling and interval mapping.

Increased twinning incidence in beef cattle has the potential to improve production efficiency. However, phenotypic selection for twinning rate is difficult because of the trait's low heritability and the long time interval necessary to collect phenotypic records. Therefore, this trait and the correlated trait of ovulation rate are ideal candidates for marker-assisted selection. The objective of this study was to complete a genome-wide search for ovulation rate quantitative trait loci (QTL) in two related sire families. The families (paternal halfsib sires 839802 and 839803) were from a population of cattle selected for ovulation rate at the USDA Meat Animal Research Center, Clay Center, Nebraska. Putative ovulation rate QTL have previously been identified in the 839802 family on chromosomes 7 and 19; however, marker coverage in the original scan was not complete. This study fills the gaps in marker coverage of the earlier study by adding approximately 60 informative microsatellites to each sire family. Each family was genotyped using selective DNA pooling. Sons and daughters were included in either the high or low pool based on their estimated breeding value deviations from the mid-parent average (EBVMD) for ovulation rate. Approximately 40% (839802) and 26% (839803) of available progeny comprised the high and low pools combined. Pooled typing revealed possible associations (nominal P < 0.05) between ovulation rate and marker genotype for 11 and 15 microsatellites in the 839802 and 839803 families, respectively. Subsequent interval mapping strengthened support for the presence of an ovulation rate QTL on BTA14 (chromosome-wise P < 0.02).

Animals↗
PubMed1993

Dissection of the functional architecture of a plant defense gene promoter using a homologous in vitro transcription initiation system.

CHS15 is one of a family of bean genes encoding chalcone synthase, which catalyzes the first reaction in a branch pathway of phenylpropanoid biosynthesis for the production of flavonoid pigments and UV protectants and isoflavonoid-derived phytoalexins. The functional architecture of the CHS15 promoter was dissected by a novel homologous plant in vitro transcription initiation system in which whole-cell and nuclear extracts from suspension-cultured soybean cells direct accurate and efficient RNA polymerase II-mediated transcription from an immobilized promoter template. Authentic transcription from the CHS15 promoter template was also observed with whole-cell extracts from suspension-cultured cells of bean, tobacco, and the monocot rice, and the soybean whole-cell extract transcribed several other immobilized promoter templates. Hence, this procedure may be of general use in the study of plant gene regulation mechanisms in vitro. Assay of the effects of depletion of the soybean whole-cell extract by preincubation with small regions of the CHS15 promoter or defined cis elements showed that trans factors that bind to G-box (CACGTG, -74 to -69) and H-box (CCTACC, -61 to -56 and -121 to -126) cis elements, respectively, make major contributions to the transcription of the CHS15 promoter in vitro. Both cis element/trans factor interactions in combination are required for maximal activity. Delineation of these functional cis element/trans factor interactions in vitro provides the basis for study of the mechanisms underlying developmental expression of CHS15 in pigmented petal cells established by G-box and H-box combinatorial interactions, and for characterization of the terminal steps of the signal pathway for stress induction of the phytoalexin defense response.

Acyltransferases↗
PubMed1992

Long-term influence of anticonvulsant agents on calcitonin, parathyroid hormone and osteocalcin.

It has been reported that anticonvulsant drugs decrease serum calcitonin; this effect may be dose dependent and/or hypocalcemia dependent. The objective of the present study is to assess such a dependence and to evaluate other parameters in relation to calcitonin. Serum calcitonin, parathyroid hormone and osteocalcin were determined through RIA, and serum calcium, total protein and alkaline phosphatase through an autoanalyzer in 17 patients undergoing long-term treatment with phenytoin and phenobarbital. At the same time, 20 normal subjects were studied and served as controls. In the patients, no changes were observed in calcitonin, parathormone, osteocalcin and calcemia corrected for protein, and there was a statistically significant increase in alkaline phosphatase values (p < 0.001). Calcemia correlated positively with calcitonin (p < 0.01) and negatively with parathormone (p < 0.05). There was no calcitonin correlation with the anticonvulsant dosage or with the total doses ingested. Increased alkaline phosphatase levels in the presence of normal osteocalcin figures suggest a hepatic origin of the former. The fact that there were no calcitonin level changes but a correlation did exist between calcitonin and calcemia leads us to think that any hormonal changes induced by anticonvulsant agents may act indirectly through changes induced in serum calcium.

Adult↗
PubMed1991

Promoter-dependent phosphorylation of RNA polymerase II by a template-bound kinase. Association with transcriptional initiation.

The largest subunit of eukaryotic RNA polymerase II (RNAP II) has a serine- and threonine-rich C-terminal domain (CTD) that may interact both with DNA and with the activating region of transcription factors. It has been proposed, in one model, that a protein kinase phosphorylates the promoter-associated CTD, facilitating the transition between promoter-binding and RNA-elongating forms of RNAP II. An immobilized template transcription system was used to test the predictions of this model directly. A protein kinase that phosphorylated the CTD at multiple sites was detected. This activity was tightly bound to the template, as evidenced by continued association after multiple rounds of washing. Phosphorylation was promoter sequence-dependent and exhibited the same nucleotide substrate specificity as the previously characterized ATP-requiring step in initiation. It was necessary for [gamma-32P]ATP and initiating rNTPs to be present simultaneously in the reaction in order to efficiently chase-radiolabel into elongating RNAP II-containing complexes, consistent with the idea that initiation and phosphorylation are temporally associated reactions.

Adenosine Triphosphate↗
PubMed1991

Effect of the MN t(1;4) translocation on some economic traits of the chicken.

The F2 progeny from an original mating between chickens that were carriers of the MN t(1;4) chromosome translocation and the inbred WI-ES line were compared to determine if the translocation had any effect on selected economic traits. Homozygous translocation (TT), heterozygous translocation (TN), and karyotypically normal (NN) individuals were compared. Traits analyzed were body weight at 8, 18, 39, and 55 wk of age; shell deformation; Haugh units; egg weights at 32 and 55 wk of age; sexual maturity; egg production; and male fecundity. The TT group had greater body weights at 39 and 55 wk than the TN and NN groups, and at 55 wk the TN group was heavier than NN group. Shell deformation was greater for TT birds at 32 wk. At 32 wk, Haugh units of the TT and TN birds, and the TN and NN birds were not significantly different. The TT eggs were heavier than the TN eggs at 32 wk, which in turn were heavier than the NN eggs. Sexual maturity was reached in the order NN, TN, then TT. Eggs from TT males had the lowest fertility and highest percentage of late dead embryos. There were increased early deaths among embryos from heterozygous males. An unexplained higher number of pips among embryos from normal males was noted. No differences were noted among any other traits in either sex. Results suggest that this translocation may have some effect on production traits.

Animals↗
PubMed1989

Promoter-dependent transcription by RNA polymerase II using immobilized enzyme complexes.

DNA fragments containing the adenovirus 2 major late or simian virus 40 early promoters were attached to a solid support via a biotin-streptavidin linkage at one end of the fragment, upstream of the RNA start site. Templates immobilized in this manner were incubated with HeLa cell nuclear extracts to form preinitiation complexes containing RNA polymerase II and accessory proteins required for faithful in vitro transcription. These complexes did not require ATP or dATP for assembly, were sensitive to 0.25% Sarkosyl, and were stable to extensive washing. Their incubation with specific combinations of nucleoside triphosphates resulted in the initiation of RNA chain polymerization in situ, while addition of the remaining nucleoside triphosphates was necessary to produce a full length runoff RNA. Transcriptional activity associated with preinitiation complexes was purified approximately 300-fold, relative to the unfractionated nuclear extract. The use of immobilized template permits considerable flexibility in experimental design, as substrates and inhibitors can be added and washed out of the reaction at each step. We exploited this property of the system to dissect the temporal substrate requirements for initiation of RNA synthesis. It is known from prior work that at least one step in the promoter-dependent RNA synthesis reaction requires an adenosine nucleotide that is hydrolyzable at the beta, gamma-position. This requirement is independent of the initiating nucleotide and can be satisfied by dATP, which is not ordinarily incorporated into the RNA product. We show here that the beta, gamma-hydrolyzable adenosine nucleotide must be present simultaneously with the initiating nucleoside triphosphates. No reaction occurred when complexes were incubated with dATP, washed to remove dATP, and incubated subsequently with the two initiating nucleotides.

Adenine Nucleotides↗
PubMed1988

Effects of prenatal and postnatal fraternity size on long-term reproduction in mice.

Effects of prenatal and postnatal fraternity size (size of litter in which an animal develops prior to birth or is reared following birth) on long-term reproduction were studied by rearing 178 female ICR mice in standardized prenatal and postnatal fraternities. Three levels of prenatal and postnatal fraternity sizes were used in a 3 x 3 factorial experiment. Prenatal fraternity size was standardized by selectively terminating fetal development in pregnant females carrying at least 14 conceptuses. Prenatal fraternities were standardized to either 6, 10 or 14 fetuses, and postnatal fraternities were standardized by randomly assigning individuals to nurse litters of 5, 10 or 15 pups. Prenatal fraternity size negatively affected average pup weight at birth (P less than .05) but had little subsequent effect on growth or reproduction. Postnatal fraternity size negatively affected weight at weaning (P less than .01), with mice reared in smaller postnatal fraternities being heavier than those reared in larger fraternities. Following weaning, mice reared in smaller fraternities gained weight less rapidly (P less than .01) but still tended to be heavier at maturity (P = .11). Vaginal opening occurred at older ages in females reared in larger postnatal litters (P less than .01). An interval mating system was used to examine fraternity size effects on long-term reproduction. Females were exposed to males six times at 8-wk intervals with initial mating at 7 wk of age. Postnatal fraternity size and age at mating jointly affected litter size (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Ultrastructural and cytochemical demonstration of peroxisomes in cultured fibroblasts from patients with peroxisomal deficiency disorders.

The oxidation of very long chain fatty acids and synthesis of ether glycerolipids (plasmalogens) occurs mainly in peroxisomes. Zellweger's cerebrohepatorenal syndrome (CHRS) is a rare, inherited metabolic disease characterized by an apparent absence of peroxisomes, an accumulation of very long chain fatty acids, and a decrease of plasmalogens in tissues and cultured fibroblasts from these patients. As peroxisomes are ubiquitous in mammalian cells, we examined normal and CHRS-cultured fibroblasts for their presence, using an electron microscopic histochemical procedure for the subcellular localization of catalase, a peroxisomal marker enzyme. Small (0.08-0.20 micron) round or slightly oval peroxisomes were seen in both normal and CHRS fibroblasts. The number of peroxisomes was analyzed morphometrically and found to be significantly reduced in all CHRS cell lines. These results are discussed in relation to the underlying defect in peroxisomal function and biogenesis in this disease.

Catalase↗
PubMedDate not supplied

[Cerebral activation during movement of both hands. A study with transcranial Doppler].

INTRODUCTION AND OBJECTIVE: In healthy persons, the force carried out by a group of muscles doing bilateral exercise with maximum effort is less than that done during unilateral exercise. The nervous control of movement is probably different in these two cases. Our objective was to study and compare cerebral activation on movement of one and of both hands by means of transcranial Doppler (TCD). MATERIAL AND METHODS: We studied 30 healthy volunteers (19 men and 11 women; average age 65.4 +/- 9.5 years). Using transtemporal TCD we assessed the relative changes in average velocity of flow in both middle cerebral arteries during the exercise of sequential opposition of the fingers of one hand and of both hands. RESULTS: The activity due to the exercise of the hand contralateral to the hemisphere being studied was greater than that due to exercise of both hands together, both on the right side (p < 0.001) and on the left (p < 0.001). CONCLUSIONS: The functional activity of each cerebral hemisphere is not necessarily greater when both hands are exercised than when the contralateral hand is used, and may even be less. The possible increase in activity due to the additional contribution to ipsilateral movement in the first case may be compensated by simultaneous transhemispherical inhibition.

Adult↗
PubMedDate not supplied

[The pyramidal tract: new pathways].

OBJECTIVE: To review some anatomofunctional aspects of the pyramidal tract which are relevant in clinical practice, especially the newer concepts. DEVELOPMENT: a) Although the motor function is best known, the pyramidal tract also has sensory functions, modulating the transmission of impulses in the spinal cord. In fact, motor function is a recent acquisition on the evolutionary scale. b) Other descending pathways, such as the cortico reticulospinal path, participate in voluntary movements. However, the pyramidal pathway is necessary for fine movements of the hand. c) Most of the pyramidal fibres control movements of the contralateral side of the body, but there are a few fibres which do not cross to the other side and play a part in ipsilateral body movements. These fibres seem to contribute to motor recovery following a brain lesion. d) Classically it is recognized that the motor cortex and pyramidal fibres follow a somatotopical distribution. Nevertheless territories corresponding to different parts of the body are superimposed to a considerable extent and may be modified on very diverse occasions. e) Experimentally it has been proved that a circumscribed lesion of the pyramidal pathway does not cause hyper reflexia or spasticity. The hyper reflexia and spasticity habitually seen in patients with pyramidal syndrome is due to lesions of other descending pathways. CONCLUSION: The pyramidal tract is anatomically and functionally related to other nerve structures and its activity is therefore integrated within the nervous system.

Animals↗