REPRODUCTIVE ISOLATION AND DISTINCT POPULATION STRUCTURES IN TWO TYPES OF THE FRESHWATER SHRIMP PALAEMON PAUCIDENS

Twenty local populations of the Japanese freshwater shrimp Palaemon paucidens were electrophoretically and morphologically surveyed. Based on the diagnostic distributions of some alleles at Gpi, Mpi, Mdh-1, and Mdh-2, these populations were largely classified into two types (A and B). The A type occurred in lakes, ponds, and rivers, while the B type was observed only in rivers. Average Nei's genetic distance (D) between the two types fell into the subspecies range . The coefficient of gene differentiation, G_ST, varied considerably between the two types. In 12 populations of the A type, with a G_ST value of 0.281, nine pond and lake populations showed a higher G_ST (0.246) than the three river populations (0.151). On the other hand, G_ST was 0.036 for the eight local populations of the B type. The lower rostrum tooth number had a mode of two in type A and three in type B. Type-A populations largely varied in the upper rostrum tooth number and egg size but type B did not. Under laboratory conditions, mating frequently occurred within each type, but not between types. Furthermore, no embryonic development was observed in the few cases of intertype mating. These results indicate that the A and B types had experienced cladogenic separation with pre- or postmating isolation, whereafter the A type, under geographic isolation, underwent genetic and phenotypic differentiation, while the B type, under extensive gene flow, did not undergo differentiation.     

Sexing of half-embryos produced by microsurgical bisection of mouse morulae and production of chimeric mouse of defined sex composition by aggregating two sexed half-embryos

Using the halved morulae of mice obtained with microsurgical technique, the following two experiments were performed. 1) Sexing of half-embryos by chromosomal analysis and transfer of the half-embryos after determining the sex of the other monozygotic half. One half of the bisected embryo was cultured in Colcemid solution (0.04 micrograms/ml) to be ensured for chromosomal preparation. More than 50% (152/270) of the blastulated embryos from the halves could be sexed by direct sex chromosome analysis. Thirty-nine of the half-embryos of which the co-twin halves were sexed, were transplanted in to the uterine horns of 18 pseudopregnant mice, and twelve became pregnant. The autopsies of them on Day 18 to 20 of pregnancy, revealed the presence of 16 fetuses. The morphological sex of these fetuses thus obtained coincided completely with the previous judgement based on the chromosomal sexing. 2) Production of chimeras of defined sex composition by aggregating two half-morulae of defined sex. Out of 147 pairs of half-morulae of two different strains (ICR and C3H/He), which were replaced in pairs into empty zona pellucidae, 107 (72.8%) were aggregated successfully and developed in vitro into full expanding blastocysts of typical form. Among the 107 aggregate blastocysts, 31 were sexed for both component embryos by chromosomal analysis on the co-twin half-embryos. When these 31 blastocysts were transferred, 11 living offspring including 4 chimeras were obtained. Transfer of 12 male-male and 5 female-female aggregate blastocysts resulted in 8 males and 1 female, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Complete 1H-NMR spectral assignments for globotriaosyl-Z- and isoglobotriaosyl-E-ceramide

Two-dimensional scalar-correlated (COSY) 1H-NMR spectra of the title compounds, and phase-sensitive COSY spectrum of lactosylceramide, have been fully assigned and some spectral reassignments for related structures suggested. Glycosylation-induced shifts, and shielding by Z- and E-ceramide residues are discussed.     

Provocation of a paradoxical growth hormone response to corticotropin-releasing hormone by pretreatment with metoclopramide in patients with acromegaly and normal subjects

Two of 7 patients with acromegaly and one of 7 normal subjects exhibited a paradoxical rise in growth hormone (GH) to human corticotropin-releasing hormone (CRH) when pretreated with metoclopramide, although CRH alone did not induce an increase in GH. In one of these two patients with acromegaly, the GH increase to metoclopramide alone also reached the criteria of a paradoxical response. These two acromegalic patients showed a GH increase to metoclopramide pretreatment before and up to two months after surgery. In another acromegalic patient, whose GH level remained high 5 months after surgery, metoclopramide induced an increase in GH level, while in a patient who had an above-normal GH level 18 months after surgery, the resumption of physiological GH secretion after surgery was evidenced by a postoperative absence of a GH response to metoclopramide. It is suggested from these results that the GH response to metoclopramide and the metoclopramide-provoked GH response to CRH in patients with acromegaly result from the secretion of GH from nonadenomatous cells of the pituitary.     

Synthesis of 2-deoxy-4-O-phosphono-3-O-tetradecanoyl-2-[(3R)- and (3S)-3-tetradecanoyloxytetradecanamido]-D-glucose: a diastereoisomeric pair of 4-O-phosphono-D-glucosamine derivatives (GLA-27) related to bacterial lipid A

The diastereoisomeric, 4-O-phosphono-D-glucosamine derivatives named in the title have been synthesized, starting from benzyl 2-amino-2-deoxy-4,6-O-isopropylidene-beta-D-glucopyranoside and (3RS)-3-hydroxytetradecanoic acid.     

Immunohistochemical evidence of progestin target cells in the pituitary gland of ovariectomized rat

Progestin (P) target cells were identified in the pituitary gland of gonadectomized female rats which had been primed with estrogen (E). P staining was localized using the immunohistochemical avidin-biotin-peroxidase (ABP) complex method. Dark brown precipitates were primarily found over the cytoplasm of cells in the pars distalis, but not in the pars intermedia nor in the pars nervosa. The majority of P-sensitive cells in the pars distalis were identical with luteotrophs, a few being lactotrophs. These observations suggest a role of P in the regulation of production and secretion of gonadotrophins in the pituitary glands of female rats.     

Isolation and characterization of a monoclonal nonspecific suppressor factor (MNSF) produced by a T cell hybridoma

By fusing Con A-activated BALB/c mice spleen cells with AKR thymoma BW5147 cells, we prepared a hybridoma producing a monoclonal nonspecific suppressor factor (MNSF). This factor inhibits a generation of LPS-induced immunoglobulin-secreting cells. We used ELISA for the bioassay of MNSF activity. With this method, a stable E17 hybridoma clone was selected, and its product in culture medium was isolated and characterized. MNSF fractionated on Sephadex G-100 in saline buffer shows a form with multiple m.w., but fractionated in 0.4 M pyridine-acetic buffer, it is limited to two species of approximately 24Kd and 16Kd. The MNSF was purified by hydroxyapatite chromatography, with marked effectiveness. MNSF activity was found exclusively in the 0.35 M sodium phosphate elution, and the content was further fractionated on subsequent gel filtration in the high ionic strength buffer described above. The purified factor exhibited two forms, of 24Kd and 16Kd, and showed peaks of pI 5.3 and 5.7, respectively, on isoelectric focusing. The MNSF preparation described here is stable at 56 degrees C and unaffected by 2-mercaptoethanol, but is unstable at pH 2.0 and is sensitive to tryptic proteolysis. We injected the hybridoma cells into the peritoneal cavity of pristane-primed F1 (AKR/J X BALB/c) mice, and a large amount of pure MNSF was obtained from the ascites, the characteristics of which were similar to those in the culture supernatant. Thus, the MNSF obtained from the E17 hybridoma consists of functionally identical but physicochemically different discrete proteins. This simple method of purification can serve as a probe for further characterization of MNSF and its application in in vivo experiments.     

Spontaneous Release of γ-Aminobutyric Acid Formed from Putrescine and Its Enhanced Ca2+-Dependent Release by High K+ Stimulation in the Brains of Freely Moving Rats

The spontaneous release of [3H] gamma-aminobutyric acid ([3H]GABA) in various areas of rat brain injected with [3H]putrescine was examined using a push-pull perfusion technique. The release in a 25-min perfusate was highest in the caudate-putamen. The effect of high K+ stimulation on the release of [3H]GABA formed from [3H]putrescine was examined in the caudate-putamen. The release was enhanced by high K+ solution in a Ca2+-dependent manner.     

The effect of quercetin, a mutagenicity-enhancing agent, on the metabolism of 2-acetylaminofluorene with mammalian metabolic activation systems

The effect of quercetin as the comutagen on 2-acetylaminofluorene (AAF) was investigated. AAF was metabolized with mammalian metabolic systems (S9 mix) in the presence or absence of quercetin in vitro, and its metabolites were determined by high-performance liquid chromatography. In the presence of quercetin, the total metabolic rate of AAF decreased compared with that in the absence of quercetin, whereas the formation of N-hydroxy-AAF (N-OH-AAF) and 2-aminofluorene (AF) increased. Since the main metabolic pathway of AAF is aryl-hydroxylation, it is suggested that the decrease of total metabolic rate of AAF is due to the inhibition of aryl-hydroxylation by quercetin. From these results, it seems probable that the comutagenic effect of quercetin on AAF is due to the inhibition of aryl-hydroxylation (the detoxifying pathway) and the promotion of N-hydroxylation and deacetylation (the activating pathway) in the AAF metabolism with S9 mix.