Proteolytic processing of Blattella germanica vitellin during early embryo development

In the eggs of the cockroach Blattella germanica, vitellin (Vt) utilization is initiated 4 days postovulation by the proteolytic processing of its three subunits. These reactions yield a specific set of peptides that are consumed by the developing embryo. A yolk proteinase activity, believed central to this processing event, has been investigated. First expressed at day 3 postovulation, just prior to Vt's processing, its specific activity with synthetic substrates increased four-fold to 18-fold through day 6. In addition, a mixing experiment showed that these proteinases(s) can also process Vt's large subunits in vitro. A relationship between Vt processing and proteinase specific activity was also noted with two B. germanica translocation heterozygotes, which displayed differences in the extent of Vt processing. One group of eggs (group A) failed to process any Vt subunit. A second group (B) processed the M_r 102,000 subunit but not the M_r 95,000. A third group (C) processed their Vt normally. Proteinase specific activities in the yolk of translocant's eggs at day 6 mirrored the extent of processing, being highest in group C eggs and effectively absent from the yolk of group A eggs. Eggs defective in Vt processing also contained arrested embryos. It is concluded that the yolk proteinase activity described here participates in Vt processing at day 4 postovulation. Microscopic examination of yolk obtained from eggs of wild type females showed that, as processing began in vivo (day 4), the yolk granules also underwent an abrupt decrease in size from diameters of 15–30 μm to 3–10 μm. Yolk granules of those translocant's eggs that were defective in Vt processing did not undergo this size decrease, suggesting that granule reorganization and Vt proteolysis may be linked functionally.     

The effect of calcium supplements on plasma alkaline phosphatase and urinary hydroxyproline in postmenopausal women

Although calcium supplements are widely used in the treatment of osteoporosis, their beneficial effect is not conclusively established. We now report some effects of a calcium supplement (1 g/day) given for 6 to 12 weeks to 15 postmenopausal osteoporotic women. The mean fasting urinary hydroxyproline/creatinine ratio decreased from 0.021 +/- 0.002 to 0.015 +/- 0.001 (P less than 0.0025), indicating a significant reduction in bone resorption. The mean plasma alkaline phosphatase fell from 123 +/- 5 U/l to 104 +/- 3.1 U/l (P less than 0.01), probably representing some secondary reduction in bone formation following the inhibition of bone resorption. These results support the concept that calcium supplementation is useful in the treatment of postmenopausal osteoporosis.     

Abscisic acid deficiency prevents development of freezing tolerance in Arabidopsis thaliana (L.) Heynh.

Summary Abscisic acid (ABA) has been implicated as a regulatory factor in plant cold acclimation. In the present work, the cold-acclimation properties of an ABA-deficient mutant (aba) of Arabidopsis thaliana (L.) Heynh. were analyzed. The mutant had apparently lost its capability to cold acclimate: the freezing tolerance of the mutant was not increased by low temperature treatment but stayed at the level of the nonacclimated wild type. The mutational defect could be complemented by the addition of exogenous ABA to the growth medium, restoring freezing tolerance close to the wild-type level. This suggests that ABA might have a central regulatory function in the development of freezing tolerance in plants. Cold acclimation has been previously correlated to the induction of a specific set of proteins that have been suggested to have a role in freezing tolerance. However, these proteins were also induced in the aba mutant by low temperature treatment.     

Specific monitoring by PCR amplification and bioluminescence of firefly luciferase gene-tagged bacteria added to environmental samples

Abstract The firefly luciferase gene, luc , was demonstrated to hold promise as a specific marker for monitoring of genetically modified bacteria in the environment. PCR amplification and bioluminescence procedures were modified and compared for environmental monitoring of luc -tagged bacteria, using Escherichia coli as a model. The methods were used to track luc -tagged bacterial cells added to intact sediment core microcosms. Detection limits for the luc -tagged cells were the following, expressed as cells per 0.5 g of sediment: 10², by PCR amplification; 10³, by whole cell luminescence; and 10³−10⁴, by measurement of luminescence in cell extracts.     

Psychological complications after stillbirth--influence of memories and immediate management: population based study.

OBJECTIVE--To identify factors that may predict long term psychological complications among women who have had a stillborn child. DESIGN--Nationwide population based study using epidemiological methods. SUBJECTS--380 subjects and 379 controls who had had a stillborn or non-deformed live child in Sweden in 1991. RESULTS--Information was provided by 636 (84%) women. The ratio (95% confidence interval) of proportions of women with symptoms related to anxiety above the 90th centile for women who had had a stillborn child compared with those who had not was 2.1 (1.2 to 3.9). An interval of 25 hours or more from the diagnosis of death in utero to the start of delivery gave a ratio of 4.8 (1.5 to 15.9). The ratio was 2.3 (1.1 to 5.3) for not seeing the child as long as the mother had wished and 3.1 (1.6 to 6.0) for no possession of a token of remembrance. CONCLUSION--It is advisable to induce the delivery as soon as feasible after the diagnosis of death in utero. A calm environment for the woman to spend as much time as she wants with her stillborn child is beneficial, and tokens of remembrance should be collected.     

Relationship of scrotal circumference and testicular volume to age and body weight in the swamp buffalo (Bubalus bubalis)

Scrotal circumference (SC) and testicular volume (TV) were measured in 65 swamp buffalo bulls ranging in age from 7 to 60 months and weighing 130 kg to 560 kg. Ages and body weight (BW) were recorded for each male at the time of measurement to find out if they correlated with SC and TV. SC and TV increased linearly and correlated significantly with age and BW (SC vs age: r = 0.74, p<0.01; SC vs BW: r = 0.88, p<0.01; TV vs BW: r = 0.82, p<0.01). SC measurements ranged from 15.1 +/- 1.1 cm to 24.0 +/- 0.4 cm for ages ranging from 10.0 +/- 0.6 to 48.5 +/- 6.3 months, revealing that testicular size in swamp buffaloes was very much smaller than domestic cattle. The SC norms distributed with age would be useful in the evaluation of swamp buffalo males for breeding soundness.     

Distribution and conformation of crystalline nigeran in hyphal walls of Aspergillus niger and Aspergillus awamori.

Hyphal walls of Aspergillus awamori containing increased amount of the alpha-glucan, nigeran, became correspondingly more opaque when viewed in the electron microscope as shadowed preparations. However, increased polymer deposition was not accompanied by any significant change in wall thickness. The nigeran of both A. awamori and Aspergillus niger occurred in situ in a crystalline conformation identical to that of single crystals prepared with pure polysaccharide. Furthermore, this polymer was the dominant crystalline material in the hyphae whether or not they were enriched in nigeran. Enzymic digestion of nigeran in A. niger and A. awamori revealed that the bulk of the polymer was exposed to the cell's exterior. However, a certain fraction was accessible to enzymic attack only after the wall was treated with boiling water. A third portion, detectable only by x-ray diffraction, was associated with other components and could not be extracted, even with prolonged boiling. It was removed by hot, dilute alkali and was associated in the wall with another glucan fraction. Dry heating of A. niger walls altered their susceptibility to enzymic digestion of nigeran in situ. It is proposed that this treatment introduces interstices in the crystal surface that facilitate attack.     

Characterization of cell-surface glycopeptides from mouse cerebral cortex that inhibit cell growth and protein synthesis.

The occurrence of multiple forms of rat prolactin with different molecular weights (size heterogeneity) was studied with anterior pituitary extracts, purified rat prolactin and 125I-labelled rat prolactin. In each case, three main forms of the hormone were detected by gel filtration on Sephadex G-100: a major one (80--90%) corresponding to monomeric prolactin (mol.wt. 22000--25000), a peak (8--20%) that could be a dimer (mol.wt. 45000--50000) and a small quantity (1--5%) of a component of much greater molecular weight. On freezing and thawing of 125I-labelled rat prolactin, there was little interconversion of monomer and 'dimer' peaks, but both were converted substantially to very high-molecular-weight material. All three peaks of 125I-labelled rat prolactin could be precipitated by anti-(rat prolactin) serum and all three gave similar patterns of radioactive peptides after digestion with chymotrypsin followed by high-voltage paper electrophoresis. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the monomer peak of 125I-labelled prolactin migrated as a single component of mol.wt. 22000, the very high-molecular-weight peak largely dissociated to a component running in the same position as the monomer, and the 'dimer' peak migrated partly as a component of mol.wt. 45000 and partly as a component migrating with monomeric prolactin. No treatment was found that could dissociate the 'dimer' peak completely to monomeric prolactin.