The essential Gcd10p-Gcd14p nuclear complex is required for 1-methyladenosine modification and maturation of initiator methionyl-tRNA

Gcd10p and Gcd14p are essential proteins required for the initiation of protein synthesis and translational repression of GCN4 mRNA. The phenotypes of gcd10 mutants were suppressed by high-copy-number IMT genes, encoding initiator methionyl tRNA (tRNAiMet), or LHP1, encoding the yeast homolog of the human La autoantigen. The gcd10-504 mutation led to a reduction in steady-state levels of mature tRNAiMet, attributable to increased turnover rather than decreased synthesis of pre-tRNAiMet. Remarkably, the lethality of a GCD10 deletion was suppressed by high-copy-number IMT4, indicating that its role in expression of mature tRNAiMet is the essential function of Gcd10p. A gcd14-2 mutant also showed reduced amounts of mature tRNAiMet, but in addition, displayed a defect in pre-tRNAiMet processing. Gcd10p and Gcd14p were found to be subunits of a protein complex with prominent nuclear localization, suggesting a direct role in tRNAiMet maturation. The chromatographic behavior of elongator and initiator tRNAMet on a RPC-5 column indicated that both species are altered structurally in gcd10Delta cells, and analysis of base modifications revealed that 1-methyladenosine (m1A) is undetectable in gcd10Delta tRNA. Interestingly, gcd10 and gcd14 mutations had no effect on processing or accumulation of elongator tRNAMet, which also contains m1A at position 58, suggesting a unique requirement for this base modification in initiator maturation.     

Determination of phosphine residues in whole grains and soybeans by ion chromatography via conversion to phosphate

An ion chromatographic (IC) method was developed for determining phosphine (PH3) in whole grains (barley, corn, oats, rice, rye, and wheat) and soybeans. The method converts phosphine to phosphate (i.e., orthophosphate) and isolates the phosphate by IC with eluent-suppressed conductivity detection. Recoveries of unbound phosphine by the method were similar to those obtained by an established colorimetric method for 7 different products fortified at 3 levels. Mean recoveries were low (i.e., 30-60%) and varied with product type and level of fortification. Recoveries of PH3 from previously fumigated products fortified with aluminum phosphide ranged from 19.0% for barley fortified at 0.734 ppm to 88.3% for corn fortified at 1.691 ppm. Precision data from 3 products based on replicate analyses (n = 4 or 5) gave relative standard deviations of 1.78-4.66% for mean laboratory-fumigated PH3 levels of 0.679-1.309 ppm. Estimated limits of detection (LOD) and quantitation (LOQ) for PH3 were 0.010 microgram/g (10 ppb) and 0.0275 microgram/g (27.5 ppb) at signal-to-noise ratios (S/N) of 4:1 and 10:1, respectively. These values were also determined for a nonchemically suppressed IC system with LOD of 0.02 microgram/g (20 ppb) and LOQ of 0.055 microgram/g (55 ppb) at S/N of 4:1 and 10:1, respectively. Phosphate response was linear over the concentration range equivalent to 0.30-10.0 micrograms P/mL, with a mean correlation coefficient of 0.9988 based on replicate standard curves. The relationship of product composition to recovery from various products was also examined.     

Genomic organization of a human cystine transporter gene (SLC3A1) and identification of novel mutations causing cystinuria

Cystinuria is a common inherited aminoaciduria that leads to recurrent cystine nephrolithiasis. Mutations in a gene encoding a renal amino acid transporter (SLC3A1) have been identified in patients with cystinuria establishing one molecular cause for the disease. To facilitate systematic screening of this gene for mutations, we have delineated the complete genomic organization of the SLC3A1 coding region using polymerase chain reaction strategies. The complete coding region of the gene is contained within a single yeast artificial chromosome clone and consists of 10 exons and 9 introns. Oligonucleotide primers capable of amplifying selected exons have been made and used in mutational analysis of DNA from 24 cystinuria probands. We illustrate the usefulness of this approach by identifying two novel SLC3A1 mutations. One novel mutation causes replacement of a highly conserved arginine residue (arginine-452) with tryptophan in the cytoplasmic loop between the putative third and fourth membrane spanning segments. A second previously unreported mutation results in replacement of a highly conserved tyrosine (tyrosine-461) residue with histidine in the same region of the protein. In addition, we detected three previously reported SLC3A1 mutations, R270X, 1500 +1/G to T, and M467T, the latter being present in approximately 20% of cystinuria chromosomes examined. Our findings provide a foundation for the development of more accessible diagnostic screening assays for detecting SLC3A1 mutations using patient genomic DNA, and also contribute to the emerging spectrum of cystinuria genotypes.     

Ferrihydrite in water wells and bacterial enrichment cultures

The chemical and mineralogical composition of Fe(III)-precipitates formed in water wells and laboratory cultures was examined. Ferrihydrite, a poorly ordered Fe(III)-oxide of bulk formula 5Fe₂O₃ · 9H₂O, was detected by X-ray diffraction analysis in all samples. The crystallinity varied from one sample to another. Fe was the only major element detected by energy-dispersive X-ray spectrometry; several other elements were present at minor levels reflecting the chemical composition of the medium. The results suggest that the biologically-catalyzed iron encrustation of water wells begins with the initial formation of ferrihydrite.     

Design considerations and operating characteristics of high-poweractive grating-surface-emitting amplifiers

An analysis of the characteristics and optimization of the design parameters of active-grating surface emitting amplifiers is presented. It is concluded that coherent power outputs of more than 1 W with ⩽30 dB of amplified spontaneous emission noise power contained in the far-field beam divergence of the coherent output are expected for amplifier lengths greater than 0.5 cm. The effects of end reflections on the active-grating amplifier power output are also considered, and it is found that end reflections of 10^-3 or less should have a negligible effect on the power output     

Criteria for family assessment in research and intervention contexts.

Highlights the distinctive family assessment needs of the family clinician and researcher. The family researcher's goal of validating scientific theory demands assessment measures that are amenable to statistical manipulation, possess construct validity, and are at least moderately reliable. The family-oriented clinician demands multiple compatible measures that demonstrate treatment utility for particular populations and phases of interventions. Critical aspects of psychometric standards of reliability and validity may vary depending on the use for which a measure is designed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

First year growth of preterm infants fed standard compared to marine oil n−3 supplemented formula

Very low birth weight (VLBW) infants (748–1390 g, n=65) were randomly assigned to receive control or marine oil-supplemented formula when they achieved intakes >454 kJ (110 kcal)/kg/d of a formula designed for VLBW infants. Study formulas with or without marine oil were provided until 79 wk of postconceptional age (PCA), first in a formula designed for preterm infants followed by a formula designed for term infants. Infants were studied at regular intervals through 92 wk PCA. Weight, length, and head circumference were determined by standardized prodedures and normalized to the National Center for Health Statistics figures for growth of infants born at term of the same age and gender. Mean normalized weight, weight-to-length, and head circumference were greatest at 48 wk and decreased thereafter. The decline in normalized weight was greater in infants fed the marine oil-supplemented formula. Beginning at 40 wk, marine oil-supplemented infants compared to controls had significantly poorer Z-scores for weight, length and head circumference. In addition, birth order (negatively) and maternal height (positively) influenced weight and length achievement in infancy as shown previously in infants born at term. Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Twenty-four-hour ambulatory blood pressure and heart rate monitoring in combat-related posttraumatic stress disorder

This study examined the cardiovascular correlates of posttraumatic stress disorder (PTSD) in Vietnam combat veterans using 24-hr ambulatory blood pressure and heart rate monitoring. Veterans with PTSD (n = 11) exhibited significantly higher heart rate and diastolic blood pressure across the 24 hr than veterans without PTSD (n = 7) (80.8 vs. 71.9 bpm, and 80.1 vs. 71.5 mm Hg, respectively). Heart rate during sleep was also significantly higher among veterans with PTSD, compared to veterans without PTSD (71.0 vs. 62.7 bpm). These results, based on a more naturalistic measurement methodology used outside the laboratory, support an association between PTSD and increased chronic cardiovascular arousal.