Blushing as a function of audience size

Almost no experimental analysis of blushing has been done since Darwin's observations in 1872. Forty-eight college women watched a videotape intended to elicit blushing, and a videotape not intended to elicit blushing, but elicit physiological responses. A subject was alone, or with one or four persons present. Blushing, which was measured directly with a photoplethysmograph probe on the cheek, was greater during the blushing than nonblushing stimulation. Blushing increased as audience size increased from one to four, but not from zero to one. Audience size and kind of stimulation interacted statistically. Similar results were obtained with ear coloration, cheek temperature, and skin conductance responses, although confidence levels were lower. Cheek coloration and temperature were significantly correlated during nonblushing stimulation, and the zero and one audience conditions, but not during the four audience condition, when blushing was greatest. These results may be placed within the context of emotional effects of audience size generally, including stuttering and speech disturbance, disruption of learning, and self-reported tension.

Yeast KRE2 defines a new gene family encoding probable secretory proteins, and is required for the correct N-glycosylation of proteins

We have cloned, sequenced and disrupted the KRE2 gene of Saccharomyces cerevisiae, identified by killer-resistant mutants with a defective cell wall receptor for the toxin. The KRE2 gene is close to PHO8 on chromosome 4, and encodes a predicted 49-kD protein, Kre2p, that probably enters the secretory pathway. Haploid cells carrying a disruption of the KRE2 locus grow more slowly than wild-type cells at 30 degrees, and fail to grow at 37 degrees. At 30 degrees, kre2 mutants showed altered N-linked glycosylation of proteins, as the average size of N-linked outer chains was reduced. We identified two other genes, YUR1 on chromosome 10, and KTR1 on chromosome 15, whose predicted products share 36% identity with Kre2p over more than 300 amino acid residues. Yur1p has an N-terminal signal sequence like Kre2p, while Ktr1p has a predicted topology consistent with a type 2 membrane protein. In all cases the conserved regions of these proteins appear to be on the lumenal side of secretory compartments, suggesting related function. KRE2, KTR1 and YUR1 define a new yeast gene family.

Marriage law and practice in the Sahel

The legal systems of Sahelian African countries combine customary law, Islamic law, French colonial law, and civil law introduced since independence in 1960. Utilizing a framework developed by the Faculty of Law, University of Dakar, Senegal, and the Development Law and Policy Program, Center for Population and Family Health, Columbia University, the Sahel Institute undertook a comprehensive study of the legal and social status of women in Burkina Faso, Mali, Niger, and Senegal. Since 1960, Burkina Faso, Mali, and Senegal have replaced French family law with national marriage codes. Niger has not yet adopted a family code; the laws on the family inherited from the French remain in force. The postindependence marriage codes have attempted to give young women more say in choosing a husband, to regulate the practice of bride price, and to limit the practice of polygyny. They have done this by integrating customary law and government-passed civil law. Mali, Niger, and Senegal have repealed provisions in their codes prohibiting the distribution of contraception, based on a 1920 French law. Although it has taken no formal legal action, Burkina Faso has adopted family planning policies that effectively nullify the 1920 law.

Dynamic interplay between two copper-titrating components in the transcriptional regulation of cyt c6

The algal plastidic cytochrome c (cyt c6) is a biochemical equivalent of the copper-containing protein plastocyanin in photosynthetic electron transfer. But generally, cyt c6 accumulates and functions only under conditions (e.g. Cu-deficiency) where holoplastocyanin cannot be synthesized. In studying the regulation of Chlamydomonas reinhardtii cyt c6 expression by Cu we have determined that repression of cyt c6 accumulation occurs at the transcriptional level, and specifically in response to Cu as the metal ion regulator. Complete and sustained repression of cyt c6 transcription requires approximately 9 x 10(6) Cu ions in the medium/cell. Based on the estimated plastocyanin content of algal cells (8 x 10(6) molecules/cell) and the observation that lower ratios of Cu per cell result in only transient repression of cyt c6 transcription, we propose that Cu-dependent transcriptional repression of the gene encoding cyt c6 requires a Cu-binding factor which is titrated by Cu only after the alternate electron transfer catalyst, plastocyanin, has accumulated to the stoichiometry required for photosynthesis. The precise and highly metal-specific, autoregulatory control of cyt c6 levels--directly by Cu, and indirectly by holoplastocyanin--is in keeping with the functional role of cyt c6 as an alternate, although perhaps less preferred, electron transfer catalyst.

Approaches to the measurement of childhood mortality: a comparative review

"In the developing world, measures of child mortality are needed for a variety of purposes, and estimates of child mortality can be obtained by a variety of approaches. In this paper, the author reviews the characteristics that child mortality measures should have for particular purposes, and then examines the available measurement approaches to determine the extent to which they provide accurate measures with the required characteristics. Particular emphasis is put on the comparative performance of different approaches in different settings to produce estimates of recent levels and trends in child mortality. He concludes that no single approach can satisfy all measurement purposes and that all approaches are sensitive to the quality of data collection, but that many needs can be met by relatively inexpensive data collection and analysis methods."

Seasonal variations in urinary risk factors among patients with nephrolithiasis

Twenty-four hour urine specimens from 5,677 stone-forming patients throughout the United States were analyzed for seasonal variations in urinary risk factors for nephrolithiasis. Determinations were performed for urine volume, pH, calcium, oxalate, phosphorus, sodium, magnesium, citrate, sulfate, uric acid, and the relative supersaturation (RS) of calcium oxalate, brushite, monosodium urate, and uric acid. Criteria for significant seasonal variation included a significant difference in monthly means of risk factors, seasonal grouping of the data by the Student-Newman-Keuls multiple range test, consistent year-to-year trends and a physiologically significant range. Minimum urine volume of 1.54 +/- 0.70 SD L/day occurred in October while a maximum urine volume of 1.76 +/- 0.78 SD L/day was observed during February. Minimum urine pH of 5.94 +/- 0.64 SD was observed during July and August while a maximum pH of 6.18 +/- 0.61 SD was observed during February. Daily urinary excretion of sodium was lowest during August, 158 +/- 74 SD mEq/day and highest during February 177 +/- 70 SD mEq/day. The RS of brushite and uric acid were found to display significant pH-dependent seasonal variation with a maximum RS of uric acid 2.26 +/- 1.98 SD in June and a low of 1.48 +/- 1.30 SD in February. Maximum RS of brushite 2.75 +/- 2.58 was observed during February. Minimum RS of brushite 1.93 +/- 1.70 SD was observed in June. Phosphorus excretion displayed seasonal variation about a spring-fall axis with a maximum value 1042 +/- 373 SD mg/day in April and a minimum value of 895 +/- 289 SD mg/day. Urine volume, sodium, and pH were significantly lower during the summer (June, July, August) than in the winter (December, January, February). The RS of uric acid was higher, but that of brushite and monosodium urate was lower in the summer than in the winter. The seasonal changes observed in urine volume, pH, sodium, and the RS of brushite and uric acid are consistent with summertime sweating and increased physical activity. Seasonal variations in phosphorus excretion are probably dietary in origin. The summertime was characterized by an increased propensity for the crystallization of uric acid but not of calcium oxalate or calcium phosphate.

A multicenter, prospective study of fetal outcome following accidental carbon monoxide poisoning in pregnancy

We report the results of the first prospective, multicenter study of acute carbon monoxide (CO) poisoning in pregnancy. We collected and followed cases of CO poisoning occurring during pregnancy between December 1985 and March 1989. The sources of CO were malfunctioning furnaces (n = 16), hot water heaters (n = 7), car fumes (n = 6), and methylene chloride inhalation (n = 3). Pregnancy outcome was adversely affected in 3 of 5 pregnancies with severe toxicity; two stillbirths, and one cerebral palsy with tomographic findings consistent with ischemic damage. All adverse outcome occurred in cases treated with high flow oxygen, whereas the 2 cases of severe toxicity with normal outcomes followed hyperbaric oxygen therapy. All 31 babies exposed in utero to mild or moderate CO poisoning exhibited normal physical and neurobehavioral development. Severe maternal CO toxicity was associated with significantly more adverse fetal cases when compared to mild maternal toxicity (P less than 0.001). It is concluded that while severe CO poisoning poses serious short- and long-term fetal risk, mild accidental exposure is likely to result in normal fetal outcome. Because fetal accumulation of CO is higher and its elimination slower than in the maternal circulation, hyperbaric oxygen may decrease fetal hypoxia and improve outcome.

Facial coloration and temperature responses in blushing

Little work on the psychophysiology of blushing has been done since Darwin's 1872 observations. Facial vascular and temperature changes have been largely ignored in psychophysiology. We had 16 female and 16 male undergraduate volunteers watch a videotape intended to produce blushing (the individual's singing recorded the previous day), and a videotape not intended to produce blushing, but elicit physiological responses for comparison (a segment from Hitchcock's movie Psycho). Four people were present as a subject watched these video segments. Cheek and ear coloration, measured photoplethysmographically, cheek temperature, and finger skin conductance responses were significantly greater during stimulation intended to elicit blushing than during comparison stimulation. Gender interacted statistically with kind of stimulation only in cheek temperature. Only video segments of the subject's face that coincided with maximal cheek coloration during stimulation intended to produce blushing were judged reliably as blushing, and then more often in females than in males.

Isolation and characterization of a complementary DNA clone for an algal pre-apoplastocyanin

We have isolated a cDNA clone for the Chlamydomonas reinhardtii pre-apoplastocyanin. The sequence contains codons for the complete pre-protein including a two-domain, lumen-targeting transit sequence and the mature apoprotein. The transit sequence (47 amino acids) is the shortest one described for chloroplast lumenal proteins, and like other C. reinhardtii lumen-targeting transit sequences appears to lack an uncharged amino-terminal domain usually present in plant lumen-directing sequences. The mature protein is deduced to be 98 amino acids in length and shows highest primary sequence similarity (74-76% identity) to other unicellular algal plastocyanins. Southern hybridization analysis of C. reinhardtii genomic DNA indicates the presence of a single nuclear gene, as is the case for all other plastocyanin genes characterized to date, although the algal gene might be interrupted. Codon usage in this gene reflects the high GC content of C. reinhardtii nuclear DNA, but is more highly biased than that found in the C. reinhardtii copper-repressible gene for the functionally equivalent pre-apocytochrome c552 (perhaps contributing to the more efficient synthesis in vivo of plastocyanin over cytochrome c552). The deduced physical properties of this plastocyanin are compared to those of the C. reinhardtii plastidic cytochrome c552.

The yeast KRE5 gene encodes a probable endoplasmic reticulum protein required for (1----6)-beta-D-glucan synthesis and normal cell growth

Yeast kre mutants define a pathway of cell wall (1----6)-beta-D-glucan synthesis, and mutants in genes KRE5 and KRE6 appear to interact early in such a pathway. We have cloned KRE5, and the sequence predicts the product to be a large, hydrophilic, secretory glycoprotein which contains the COOH-terminal endoplasmic reticulum retention signal, HDEL. Deletion of the KRE5 gene resulted in cells with aberrant morphology and extremely compromised growth. Suppressors to the KRE5 deletions arose at a frequency of 1 in 10(7) to 1 in 10(8) and permitted an analysis of deletions which were found to contain no alkali-insoluble (1----6)-beta-D-glucan. These results indicate a role for (1----6)-beta-D-glucan in normal cell growth and suggest a model for sequential assembly of (1----6)-beta-D-glucan in the yeast secretory pathway.

A nucleotide that enhances the charging of RNA minihelix sequence variants with alanine

We showed earlier that a single G3.U70 base pair within the amino acid acceptor helix is a major determinant of the identity of tRNA(Ala). In addition, we demonstrated that an RNA hairpin minihelix that recreates the 12 base pair acceptor-T psi C stem of tRNA(Ala) is also aminoacylated in a G3.U70-dependent manner. Determinants for efficient aminoacylation at pH 7.5 have been further investigated with minihelix substrates that have sequence variations at 3.70 and other locations. Although a U,U mismatch and other 3.70 nucleotide alternatives to G.U were recently proposed by others as also important for alanine acceptance, neither that mismatch nor any of four other 3.70 nucleotide combinations confer aminoacylation in vitro with alanine, even with substrate levels of enzyme. In contrast, permutations of the so-called discriminator nucleotide N73 (at position 73) strongly modulate, but do not block, aminoacylation of those substrates that encode G3.U70. In particular, the efficiency of G3.U70-dependent aminoacylation with alanine is strongly enhanced by having the wild-type A73. The effect of N73 alone can explain most of the difference in aminoacylation efficiency of a G3.U70-containing tRNA and a minihelix substrate whose sequences vary significantly from their tRNA(Ala) counterparts. Comparison with earlier work suggests that the substantial modulating effect of N73 is partly or completely obscured when N73 tRNA variants are expressed as amber suppressors in vivo.

Evidence that the 3' end of a tRNA binds to a site in the adenylate synthesis domain of an aminoacyl-tRNA synthetase

Aminoacylation requires that an enzyme-bound aminoacyladenylate is brought proximal to the 3' end of a specific transfer RNA. In Escherichia coli alanyl-tRNA synthetase, the first 368 amino acids encode a domain for adenylate synthesis while sequences on the carboxyl-terminal side of this domain are required for much of the enzyme-tRNAAla binding energy. The 3' end of E. coli tRNAAla has been cross-linked to the enzyme, and sequence analysis showed that Lys-73 is the major site of coupling. A mutant enzyme with a Lys-73----Gln replacement has a 50-fold reduced kcat/Km (with respect to tRNAAla) for aminoacylation but has a relatively small alteration of its kinetic parameters for ATP and alanine in the adenylate synthesis reaction. The data provide evidence that the 3' end of tRNAAla binds to a site in the enzyme domain responsible for adenylate synthesis and that a residue (Lys-73) in this domain is important for a tRNAAla-dependent step that is subsequent to the synthesis of the aminoacyladenylate intermediate.

Assessing applicants to the NASA flight program for their renal stone-forming potential

Spaceflight could provoke formation of kidney stones, in part by causing hypercalciuria and hyperphosphaturia. Applicants for spaceflight who have metabolic or environmental derangements to begin with might be particularly susceptible to stone formation in space. We, therefore, analyzed 24-h urine samples for stone-forming risk factors in 104 male applicants before their selection into the astronaut-mission specialist corps. The urinary environment was abnormally supersaturated with calcium oxalate in 25.0% of applicants, brushite in 36.5%, and monosodium urate in 66.3%, predisposing these applicants to crystallization of stone-forming calcium salts. This high level of supersaturation was caused by both "metabolic" and environmental disturbances. Thus, hypercalciuria was found in 11.5% of applicants, hyperoxaluria in 2.9%, hyperuricosuria in 18.3% and hypocitraturia in 5.8%. Environmental derangements were generally more prominent, as indicated by low urine volume of less than 2 L.d-1 in 84.6%, high urinary phosphate in 24.4%, and high urinary sodium in 10.6% of applicants. The results suggest that most of the abnormal stone risk factors disclosed among applicants for spaceflight programs were environmental in origin.

Rationale for engineering an enzyme by introducing a mutation that compensates for a deletion

Procedures are needed for the manipulation of enzymes to introduce improved catalytic efficiencies and substrate affinities, even in the absence of information on three-dimensional structure. We previously described a selection for amino acid replacements that compensate for a large polypeptide deletion in an enzyme. The rationale is that, because of the missing polypeptide sequence, compensatory replacements must create new enzyme-substrate contacts that are not present in the native protein. Here we introduce into an undeleted enzyme a mutation that compensates for a large deletion in the same enzyme. Binding and kinetic measurements show that this mutation has the same effect on the undeleted as on the deleted protein. The results suggest that a new enzyme-substrate interaction has been created by the mutation and that its contribution to the interaction energy is similar in both the deleted and undeleted molecules. Introduction of this class of mutations into enzymes may in general be useful for engineering them to have improved interactions with ligands and substrates.

Transcriptional regulation of a promoter in the men gene cluster of Bacillus subtilis

The control of men gene expression during growth and sporulation of Bacillus subtilis was examined at the transcriptional level. Two different approaches were used. (i) Steady-state levels of men-specific mRNA were measured directly. (ii) A men'-lacZ gene fusion was constructed. In both cases, it was observed that men promoter activity was maximal at the onset of sporulation and declined soon thereafter. These kinetics were similar to the pattern of menaquinone accumulation previously observed. Expression from the men promoter was independent of the presence of the products of the spo0A and spo0H genes and was enhanced by addition of glucose and glutamine to the culture medium. DNA sequence analysis of the promoter region revealed a potential recognition site for the principal vegetative form of RNA polymerase but not for any of the known minor polymerase forms. The functionality in vivo of the promoter sequence was confirmed by high-resolution S1 nuclease mapping of the transcript start site. An additional sequence element was identified that is shared by the sdhA, citG, and ctaA promoters and may indicate a common regulatory mechanism in the expression of these genes.

Modulation by calcium of the inhibitor activity of naturally occurring urinary inhibitors

The possibility that hypercalciuria could cause calcium stone formation through a mechanism other than by increasing urinary saturation of stone-forming calcium salts was explored. The effect of increasing calcium concentration on the inhibitor activity against the spontaneous precipitation of calcium oxalate was examined in whole urine (in the presence of naturally occurring inhibitors) and in synthetic media (with added inhibitors). In 11 patients with calcium nephrolithiasis, the induced hypercalciuria from calcium supplementation (600 mg/day) caused a significant fall in the urinary inhibitory activity against calcium oxalate precipitation, as shown by a decline in the formation product ratio from 12.6 +/- 1.1 SEM to 9.6 +/- 1.4 (P less than 0.005). In order to more fully explore this observation, the effect of increasing calcium concentration on the inhibitory activities of citrate (2 mM), chondroitin sulfate (0.05 mg/liter) and a heterogeneous group of naturally-occurring urinary inhibitors (1.0 mg/liter) against calcium oxalate precipitation was examined in vitro in synthetic solutions. The inhibitory actions of both citrate and chondroitin sulfate were significantly attenuated by increasing calcium concentration from 0.25 mM to 6.0 mM (P less than 0.01). However, raising the calcium concentration in synthetic media containing a mixture of partially purified urinary inhibitors produced a significant rise in the urinary inhibitory activity of this macromolecular mixture (P less than 0.01). We conclude that hypercalciuria can attenuate the inhibitory activities of citrate and chondroitin sulfate against calcium oxalate precipitation while at the same time accentuating the inhibitory activity of naturally-occurring urinary inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)