Effect of individual and group rearing on age and size at maturity of male mosquitofish, Gambusia affinis

Age and size at sexual maturity were significantly greater for male mosquitofish, Gambusia affinis Baird and Girard, reared in sib-groups than for their sibs reared individually. Age at sexual maturity averaged 43.3 and 62.1 days for individually- and group-reared males, respectively, a 43% difference; final length and weight at maturity were 7.7 and 34.2% greater, respectively, for group-reared males than for their individually-reared sibs. The results were consistent among 30 families that represented the progeny of 30 wild-caught females. The observed differences may be attributable to behavioural interactions affecting the neuroendocrine control of the maturation process, as suggested by previous studies of Xiphophorus .     

Nuclear protein transitions in cuttle-fish spermiogenesis: Immunocytochemical localization of a protein specific for the spermatid stage

The changes in basic nuclear proteins throughout cuttle-fish spermiogenesis were investigated both by immunocytochemical procedures and by isolation of late spermatid nuclei (by virtue of their resistance to sonication). Antibodies were raised in rabbits to a protein, named protein T, isolated from testis chromatin. The anti-protein T immune serum was found to recognize protein T and not histones from the testis. Immunoperoxidase staining of sections or of smears of testis with anti-protein T antibodies showed that protein T appears in the nuclei of round spermatids, is abundant in elongating spermatid nuclei, but cannot be detected in elongated spermatids. Nuclei from these elongated spermatids were isolated by sonication treatment of testis cells. A protein, named protein Sp, with the characteristic mobility of a protamine, was isolated from elongated spermatid nuclei. This protein has the same mobility as the protamine present in mature spermatozoa. Taken together, the results indicate that in cuttle-fish, nuclear protein transitions involve the replacement of histones by a spermatid-specific protein (protein T), which is replaced at the end of elongation of the nucleus by a protamine (protein Sp). Thus, spermiogenesis of the cuttle-fish (and perhaps of other cephalopods), shows two basic nuclear protein transitions, which are similar to the transitions observed in higher vertebrates such as mammals.     

Variants of the anti-Müllerian hormone gene in a compound heterozygote with the persistent Müllerian duct syndrome and his family

Summary The human genome contains a large number of interspersed simple repeat sequences that are variable in length and can therefore serve as highly informative, polymorphic markers. Typing procedures include conventional multilocus and single locus probing, and polymerase chain reaction aided analysis. We have identified simple sequences in a cosmid clone stemming from the human Y chromosome and consisting of (gata)_n repeats. We have compared these with two equivalent simple repeat loci from chromosome 12. After amplifying the tandemly repeated motifs, we detected between four and eight different alleles at each of the three loci. Codominant inheritance of the alleles was established in family studies and the informativity of the simple repeat loci was determined by typing unrelated individuals. The polymorphisms are suitable for application in linkage studies, practical forensic case work, deficiency cases in paternity determination, and for studying ethnological questions. The mutational mechanisms that bring about changes in simple repeats located both on the autosomes and on the sex chromosomes, are discussed.Professor Dr. Otto Prokop (Humboldt-Universität Berlin) on the occasion of his 70th birthday     

The gene for X-linked hydrocephalus maps to Xq28, distal to DXS52.

We report the study of five independent X-linked hydrocephalus (HSAS1) families with polymorphic DNA markers of the Xq28 region. A total of 58 individuals, including 7 living affected males and 22 obligate carriers, have been studied. Maximum lod score was 7.21 at theta = 2.40% for DXS52 (St14-1). A single recombination event was observed between this marker and the HSAS1 locus. Other markers studied were DXS296 (Z = 2.02 at theta = 2.5%), DXS304 (Z = 4.37 at theta = 7.8%), DXS74 (Z = 3.50 at theta = 0%), DXS15 (Z = 1.96 at theta = 5.7%), DXS134 (Z = 3.31 at theta = 0%), and F8C (Z = 5.79 at theta = 0%). These data confirm the localization of the HSAS1 gene to Xq28 and provide evidence for genetic homogeneity of this syndrome. In addition, examination of two obligate recombinant meioses along with multipoint linkage analysis supports the distal localization of the HSAS1 locus with respect to the DXS52 cluster. These observations are of potential interest for future studies aimed at HSAS1 gene characterization.     

Stereoselective biliary elimination of disopyramide and mono-N-desisopropyldisopyramide in humans.

The results of a previous pharmacokinetic study of disopyramide (DP) enantiomers in humans suggested that DP and/or mono-N-desisopropyldisopyramide (MND) may show stereoselective extrarenal elimination. Thus, the present study investigates the biliary elimination of DP and MND enantiomers in three patients who had undergone cholecystectomy for cholelithiasis. DP and MND enantiomers displayed biliary elimination. In both subjects, this elimination pathway showed the same characteristics: (1) biliary elimination of DP and MND was stereoselective, (2) the stereoselectivity was opposite to that observed for the metabolic and renal elimination pathways, i.e., the elimination of the (-)-(R)-enantiomer was higher than that of the (+)-(S)-enantiomer, and (3) biliary elimination of MND was higher than that of DP, for both enantiomers. Estimates of the relative contribution of the biliary clearance in the total clearance of DP and MND indicated that this elimination pathway was secondary, especially for DP. The biliary clearance (expressed as % of total clearance) was 1.9 to 4.0% for (-)-(R)-DP, 1.2 to 1.7% for (+)-(S)-DP, 7.8 to 22.9% for (-)-(R)-MND, and 5.2 to 10.5% for (+)-(S)-MND.     

The effects of two novel objects on the behavior of singly caged adult rhesus macaques.

Six female and six male adult rhesus macaques were given sticks and nylon balls as an attempt at simple cage enrichment. A latin square design was used to compare behavior during separate 4-week periods with each object and during a control period with no object. Frequency and duration of 15 different behaviors were recorded. Resting was the most common activity which decreased slightly in duration when the stick or nylon ball was present (P less than 0.02). The mean duration of stick use was longer than that of the nylon ball (P less than 0.01). No other behaviors changed significantly, including the frequency of abnormal behaviors such as self-abuse, stereotypic acts, and bizarre postures. Generally, these objects were used infrequently and led to few changes in the behavior of singly-caged adult rhesus macaques. However, they did appear to stimulate activity for some individuals.     

Cross-coupling of signal transduction pathways: zinc finger meets leucine zipper.

Cell proliferation and cellular differentiation are often thought of as opposing phenomena. The molecular mechanisms by which steroid, retinoid and thyroid hormones inhibit cellular proliferation and by which growth factors stimulate this process are poorly understood. We discuss recent evidence suggesting that these two signal transduction pathways converge through a process referred to as 'cross-coupling', which involves a possible interaction between steroid hormone receptors and the c-Jun oncoprotein.     

Antibody responses of mice exposed to low-power microwaves under combined, pulse-and-amplitude modulation

Irradiation by pulsed microwaves (9.4 GHz, 1 microsecond pulses at 1,000/s), both with and without concurrent amplitude modulation (AM) by a sinusoid at discrete frequencies between 14 and 41 MHz, was assessed for effects on the immune system of Balb/C mice. The mice were immunized either by sheep red blood cells (SRBC) or by glutaric-anhydride conjugated bovine serum albumin (GA-BSA), then exposed to the microwaves at a low rms power density (30 microW/cm2; whole-body-averaged SAR approximately 0.015 W/kg). Sham exposure or microwave irradiation took place during each of five contiguous days, 10 h/day. The antibody response was evaluated by the plaque-forming cell assay (SRBC experiment) or by the titration of IgM and IgG antibodies (GA-BSA experiment). In the absence of AM, the pulsed field did not greatly alter immune responsiveness. In contrast, exposure to the field under the combined-modulation condition resulted in significant, AM-frequency-dependent augmentation or weakening of immune responses.     

Application of natural and amplification created restriction sites for the diagnosis of PKU mutations.

PCR amplification, either conventional, or as site directed mutagenesis using primers with mismatched 3'-ends, followed by restriction endonuclease digestion, provides rapid, non-isotope assays of known mutations in the human phenylalanine hydroxylase gene. Such assays were shown to have the potential to detect all of the 18 presently reported phenylketonuria mutations. The practical applicability of this approach was demonstrated for eight mutations in Norwegian phenylketonuria patients, among them the most common ones.