Mapping a quantitative trait locus for the concentration of beta-lactoglobulin in milk, and the effect of beta-lactoglobulin genetic variants on the composition of milk from Holstein-Friesian x Jersey crossbred cows.

AIM: To identify quantitative trait loci (QTL) affecting the concentration of beta-lactoglobulin in milk, and to evaluate the effect of beta-lactoglobulin genetic variants on the concentration of fat, protein and casein in bovine milk. METHODS: A herd of 850 F2 Holstein-Friesian x Jersey crossbred cows was produced through mating six Holstein-Friesian x Jersey F1 bulls of high genetic merit with F1 cows from the national herd. A total of 1,610 herd-test records from 556 second-parity crossbreds were analysed. The concentration of fat, protein and casein in milk was measured at peak, mid- and late lactation, during the production seasons of 2003-2004 and 2004-2005. Liveweight was measured daily. DNA from the F2 animals, their F1 dams and sires, and selected grandsires was genotyped across the genome, initially with 285 microsatellite markers, and subsequently with 6,634 single nucleotide polymorphisms (SNP). RESULTS: A highly significant QTL for the concentration of beta-lactoglobulin in milk was identified, which coincided with the position of the beta-lactoglobulin gene on bovine Chromosome 11. No other consistently significant QTL for the concentration of beta-lactoglobulin in milk were detected. Cows with the BB beta-lactoglobulin genotype produced milk with a 30% lower concentration of beta-lactoglobulin than cows with the AA genotype. The beta-lactoglobulin polymorphism also explained variation in the proportion of casein in total protein. In addition, the percentage of fat was higher for BB than AA animals, whereas the percentage of total protein, mean daily milk yield and liveweight did not differ between AA and BB animals. CONCLUSIONS: A significant QTL determining the concentration of beta-lactoglobulin in milk was identified. Selection of animals for the beta-lactoglobulin B-allele may enable the production of milk naturally enriched for casein, thus allowing a potential increase in the yield of cheese. There may be additional future value in production of bovine milk more like human milk, where decreasing the concentration of beta-lactoglobulin is desirable.

Effects of the menstrual cycle on measures of personality in women with premenstrual syndrome: a preliminary study.

BACKGROUND: Previous studies suggest that women with premenstrual syndrome (PMS) differ from those without PMS in measures of personality. The purpose of this study was to measure the effect of menstrual cycle phase on personality variables in women with and without PMS. METHOD: The Personality Diagnostic Questionnaire-Revised (PDQ-R) was administered in both the follicular and luteal phases to women with PMS (according to National Institute of Mental Health PMS Workshop Diagnostic Guidelines) (N = 40). An asymptomatic control group (N = 20) as well as a symptomatic group of women with DSM-IV-diagnosed recurrent, non-menstrual-cycle-related brief depression (N = 20) also completed the questionnaire in both phases. RESULTS: Only women with PMS demonstrated a significant increase in total PDQ-R score (reflecting overall personality disorder) from the follicular to the luteal phase (p < .01). Women with PMS had significantly higher total PDQ-R scores than the asymptomatic controls during both the follicular (p < .05) and luteal (p < .01) phases, whereas there was no significant difference between women with PMS and symptomatic controls during either phase. Subscale scores fit similar patterns, as did the number of women in each group meeting a cutoff score indicative of the presence of personality dysfunction. CONCLUSION: In this preliminary study, women with PMS were unique in demonstrating a menstrual cycle phase effect on PDQ-R score, while their scores in both phases were closer to symptomatic controls than asymptomatic controls. These findings suggest that personality disorder in women with PMS may have both state- and trait-related components.

Menstrual cycle effects on cortical excitability.

OBJECTIVE: To determine whether there are menstrual cycle-related effects on cortical excitability in normal women. BACKGROUND: Ovarian steroid hormones affect neurotransmission in the brain. Data from animal experiments have shown that progesterone metabolites enhance the action of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the cortex, producing benzodiazepine-like (e.g., diazepam and lorazepam) physiologic and behavioral effects. Estradiol has excitatory effects on measures of neuronal excitability, possibly acting through the glutamate system. These effects have been difficult to detect in women using conventional techniques. However, recently, paired transcranial magnetic stimulation (TMS) has been used to detect the effects of GABAergic and glutamatergic drugs in humans. We used this method to measure the effects of the menstrual cycle in normal women. METHODS: We tested 13 healthy women during the follicular (low-progesterone) and luteal (high-progesterone) phases of the menstrual cycle using paired TMS. The effect of a subthreshold conditioning pulse on the cortex was tested by measuring the response to a second suprathreshold test pulse and comparing it with the response elicited by the test pulse administered alone. RESULTS: Conditioning TMS produced more inhibition in the luteal phase than in the follicular phase (p = 0.01), of similar magnitude to the reported effect of benzodiazepine drugs. CONCLUSIONS: This study provides the first direct evidence of changes in the excitability of a cortical network with the menstrual cycle. The results also show a potential confound for studies using transcranial magnetic stimulation in populations that include menstruating women.

Dehydroepiandrosterone treatment of midlife dysthymia.

BACKGROUND: This study evaluated the efficacy of the adrenal androgen, dehydroepiandrosterone, in the treatment of midlife-onset dysthymia. METHODS: A double-blind, randomized crossover treatment study was performed as follows: 3 weeks on 90 mg dehydroepiandrosterone, 3 weeks on 450 mg dehydroepiandrosterone, and 6 weeks on placebo. Outcome measures consisted of the following. Cross-sectional self-ratings included the Beck Depression Inventory, and visual analogue symptom scales. Cross-sectional objective ratings included the Hamilton Depression Rating Scale, the Cornell Dysthymia Scale and a cognitive test battery. Seventeen men and women aged 45 to 63 years with midlife-onset dysthymia participated in this study. Response to dehydroepiandrosterone or placebo was defined as a 50% reduction from baseline in either the Hamilton Depression Rating Scale or the Beck Depression Inventory. RESULTS: In 15 patients who completed the study, a robust effect of dehydroepiandrosterone on mood was observed compared with placebo. Sixty percent of the patients responded to dehydroepiandrosterone at the end of the 6-week treatment period compared with 20% on placebo. A significant response was seen after 3 weeks of treatment on 90 mg per day. The symptoms that improved most significantly were anhedonia, loss of energy, lack of motivation, emotional "numbness," sadness, inability to cope, and worry. Dehydroepiandrosterone showed no specific effects on cognitive function or sleep disturbance, although a type II error could not be ruled out. CONCLUSIONS: This pilot study suggests that dehydroepiandrosterone is an effective treatment for midlife-onset dysthymia.

Differential behavioral effects of gonadal steroids in women with and in those without premenstrual syndrome.

BACKGROUND: The symptoms of women with premenstrual syndrome improve in response to suppression of ovarian function, although these women have no evidence of ovarian dysfunction. We undertook a study to determine the role of estrogen and progesterone in this syndrome. METHODS: We first studied the effect of ovarian suppression with leuprolide, an agonist analogue of gonadotropin-releasing hormone, or placebo on symptoms in 20 women with the premenstrual syndrome. Ten women whose symptoms improved during leuprolide treatment were given estradiol and progesterone in a double-blind, crossover design, each for four weeks, during continued leuprolide administration. Women without premenstrual syndrome (normal women) participated in a similar protocol. Outcomes were assessed on the basis of daily self-reports by the patients and biweekly rater-administered symptom-rating scales. RESULTS: The 10 women with premenstrual syndrome who were given leuprolide had a significant decrease in symptoms as compared with base-line values and with values for the 10 women who were given placebo. The 10 women with premenstrual syndrome who were given leuprolide plus estradiol or progesterone had a significant recurrence of symptoms, but no changes in mood occurred in 15 normal women who received the same regimen or in 5 women with premenstrual syndrome who were given placebo hormone during continued leuprolide administration. CONCLUSIONS: In women with premenstrual syndrome, the occurrence of symptoms represents an abnormal response to normal hormonal changes.

Elucidation of the mechanism of CryIIIA overproduction in a mutagenized strain of Bacillus thuringiensis var. tenebrionis.

NB176 is a Bacillus thuringiensis mutant derived by gamma-irradiation of NB125 Bacillus thuringiensis var. tenebrionis (Krieg). It exhibits two interesting phenotypes: (i) oligosporogeny and (ii) twofold to threefold overproduction of the CryIIIA protein. Southern profiles of the NB176 strain showed an additional copy(s) of the cryIIIA gene located on a 4 kb HindIII fragment, in addition to the expected cryIIIA gene on a 3 kb HindIII fragment. Each cryIIIA gene-bearing HindIII fragment was cloned from NB176. The restriction map of the 3 kb HindIII fragment was identical to that published by Donovan and coworkers. Sequencing of the 4 kb HindIII fragment showed no alterations in the promoter region of the cryIIIA gene but did show replacement of the region immediately following the cryIIIA open reading frame with a sequence encoding a transposase with 50% amino acid homology to that of Tn1000. These findings suggest that the overproduction phenotype of NB176 results from extra copies of the cryIIIA gene produced from a transposition event(s) induced or stabilized by gamma-irradiation. Integration of additional copies of the cryIIIA gene into the native 90 MDa plasmid of the wild-type B. thuringiensis var. tenebrionis strain resulted in strains that made enormous crystals, many possessing greatly enhanced insecticidal activity.

Molecular cloning and characterization of two genes encoding sigma factors that direct transcription from a Bacillus thuringiensis crystal protein gene promoter.

Two sigma factors, sigma 35 and sigma 28, direct transcription from the Bt I and Bt II promoters of the cryIA(a) gene of Bacillus thuringiensis; this gene encodes a lepidopteran-specific crystal protoxin. These sigma factors were biochemically characterized in previous work (K. L. Brown and H. R. Whiteley, Proc. Natl. Acad. Sci. USA 85:4166-4170, 1988; K. L. Brown and H. R. Whiteley, J. Bacteriol. 172:6682-6688, 1990). In this paper, we describe the cloning of the genes encoding these two sigma factors, as well as their nucleotide and deduced amino acid sequences. The deduced amino acid sequences of the sigma 35 and sigma 28 genes show 88 and 85% identity, respectively, to the sporulation-specific sigma E and sigma K polypeptides of Bacillus subtilis. Transformation of the sigma 35 and sigma 28 genes into B. subtilis shows that the respective B. thuringiensis sigma factor genes can complement spoIIG55 (sigma E) and spoIIIC94 (sigma K) defects. Further, B. thuringiensis core polymerase reconstituted with either the sigma 35 or sigma 28 polypeptide directs transcription from B. subtilis promoters recognized by B. subtilis RNA polymerase containing sigma E and sigma K, respectively. Thus, sigma 35 and sigma 28 of B. thuringiensis appear to be functionally equivalent to sigma E and sigma K of B. subtilis. However, unlike the situation for sigma K in B. subtilis, the homologous sigma 28 gene in B. thuringiensis does not result from a late-sporulation-phase chromosomal rearrangement of two separate, partial genes.

Effects of occupied and unoccupied bed making on myocardial work in healthy subjects.

Strict bed rest prescribed after acute myocardial infarction provides rest for the heart in an effort to lessen myocardial work. However, bed rest has been implicated as a threat to physical and psychosocial well-being. Nurses must question whether activities associated with bed rest, such as bed making by hospital personnel while the patient is occupying the bed, actually require less myocardial work than out-of-bed activities. In this study we examined cardiovascular function of 22 healthy individuals, 10 (45.5%) men and 12 (54.5%) women ranging in age from 34 to 69 years (mean 48 years), during occupied (side to side method) and unoccupied (patient up to chair) bed making. Cardiac output, heart rate, stroke volume, systolic blood pressure, diastolic blood pressure, mean arterial pressure, total peripheral resistance, and the ratio of preejection period to left ventricular ejection time were measured by using an impedance cardiograph and vital signs monitor. Although differences between these measurements during the two bed making procedures were statistically significant (p less than 0.001), they were not deemed clinically significant for healthy subjects because they represent transient reflexive responses to posturally induced changes in venous return rather than substantial increases in myocardial work. When the goal is minimal myocardial energy expenditure, making the bed when it is unoccupied may offer a sound alternative to making an occupied bed.

The nucleotide sequence of the luxE gene of Vibrio harveyi and a comparison of the amino acid sequences of the acyl-protein synthetases from V. harveyi and V. fischeri.

The luxE gene of bioluminescent bacteria encodes the acyl-protein synthetase component of the fatty acid reductase complex. The complex is responsible for converting tetradecanoic acid to the aldehyde which serves as a substrate in the luciferase-catalyzed reaction. The nucleotide sequence of the luxE gene of Vibrio harveyi was determined and the amino acid sequence of the acyl-protein synthetase deduced. The protein consists of 378 amino acid residues and has a molecular weight of 42,965 daltons. Alignment of the V. harveyi enzyme with the V. fischeri acyl-protein synthetase showed 62% identity.

A 20-kilodalton protein is required for efficient production of the Bacillus thuringiensis subsp. israelensis 27-kilodalton crystal protein in Escherichia coli.

The 27-kilodalton (kDa) mosquitocidal protein gene from Bacillus thuringiensis subsp. israelensis has been cloned as a 10-kilobase (kb) HindIII fragment from plasmid DNA; efficient expression in Escherichia coli KM1 depends on a region of DNA located approximately 4 kb upstream (K. McLean and H. R. Whiteley, J. Bacteriol. 169:1017-1023, 1987). We have cloned the upstream DNA region and show that it contains a complete open reading frame (ORF) encoding a protein with a molecular mass of 19,584 Da. Sequencing of adjacent stretches of DNA revealed two partial ORFs: one has 55.2% identity in an overlap of 319 amino acids to the putative transposase of IS231 of B. thuringiensis subsp. thuringiensis, and the other, a 78-codon partial ORF, may be the carboxyl terminus of the 67-kDa protein previously observed in maxicells of strain KM1. A 0.8-kb fragment containing only the 20-kDa protein gene greatly enhanced the expression of the 27-kDa protein in E. coli. The introduction of nonsense codons into the 20-kDa protein gene ORF abolished this effect, indicating that the gene product, not the mRNA or DNA, is required for the enhancement. The effect of the 20-kDa protein gene on various fusions of lacZ to the 27-kDa protein gene suggests that the 20-kDa protein acts after the initiation of translation of the 27-kDa protein gene.

Characterization of extracellular Mn2+-oxidizing activity and isolation of an Mn2+-oxidizing protein from Leptothrix discophora SS-1.

Supernatant fluid from Leptothrix discophora SS-1 cultures possessed high Mn2+-ozidizing activity. Studies of temperature and pH optima, chemical inhibition, and protease sensitivity suggested that the activity may be enzymatic. Kinetic studies of unconcentrated supernatant fluid indicated an apparent Km of 7 microM Mn2+ in the 1 to 200 microM Mn2+ range. The greatest Vmax value observed was 1.4 nmol of Mn2+ oxidized min-1 micrograms of protein-1 in unconcentrated samples. When the supernatant fluid was concentrated on DEAE-cellulose and the activity was eluted with MgSO4, an Mn2+-oxidizing protein was detected in the concentrate by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Mn2+-oxidizing protein appeared to have a molecular weight of 110,000 in 10% polyacrylamide gels and of 100,000 in 8% gels. Periodic acid-Schiff base staining of overloaded polyacrylamide gels showed that the DEAE-cellulose concentrate contained abundant high-molecular-weight polysaccharides; concurrent staining of the Mn2+-oxidizing band suggested that it too contained carbohydrate components. Isolation of the protein was achieved by subjecting the DEAE-cellulose concentrate to Sephacryl gel filtration in the presence of 1% sodium dodecyl sulfate, followed by preparative electrophoresis and reverse-polarity elution. However, these procedures resulted in loss of a large proportion of the activity, which precluded recovery of the protein in significant quality.

Influence of Manganese on Growth of a Sheathless Strain of Leptothrix discophora.

Mn exerted various effects on the growth of Leptothrix discophora strain SS-1 in batch cultures depending on the concentration added to the medium. Concentrations of 0.55 to 5.5 muM Mn, comparable to those in the environment from which strain SS-1 was isolated, decreased cell yield and prolonged stationary-phase survival, but did not affect growth rate. Elevated concentrations of 55 to 910 muM Mn also decreased cell yield and prolonged survival, but growth rate was decreased as well. The addition of 1,820 muM Mn caused a decline in cell numbers followed by an exponential rise after 80 h of incubation, indicating the development of a population of cells resistant to Mn toxicity. When 360 muM Mn or less was added to growth flasks, Mn was oxidized to manganese oxide (MnO(x), where x is approximately 2), which appeared as brown particles in the medium. Quantification of Mn oxidation during growth of cultures to which 55 muM Mn was added showed that nearly all of the Mn was oxidized by the beginning of the stationary phase of growth (15 to 25 h). This result suggested that the decrease in cell yield observed at low and moderate concentrations of Mn was related to the formation of MnO(x), which may have bound cationic nutrients essential to the growth of SS-1. The addition of excess Fe to cultures containing 55 muM Mn increased cell yield to levels near those found in cultures with no added Mn, indicating that iron deprivation by MnO(x) was at least partly responsible for the decreased cell yield.