To investigate the effect of endocrine disruption of 4-nitro-3-phenylphenol (PNMPP) on immature male Wistar-Imamichi rats, the rat pituitary was exposed to PNMPP (10–5–10–9 M) for 24 h with or without gonadotropin-releasing hormone (GnRH) in experiment I. In addition, the Leydig cells (10–5–10–9 M) were exposed to PNMPP for 24 h with or without human chronic gonadotropin (hCG) in experiment II. Our results showed that the PNMPP at 10–5–10–7 M suppressed follicle-stimulating hormone (FSH) and luteinizing hormone (LH) productions from GnRH-stimulated pituitary cells. At the same time, PNMPP 10–5–10–7 M induced an increase in testosterone production from the Leydig cells treated with or without hCG. Based on our results, it can be concluded that that PNMPP might have both androgen agonist action by decreasing FSH and LH production in the pituitary and anti-androgenic action by increasing
testosterone production in the Leydig cell. 相似文献
Water management methods regulate water temperature in paddy fields, which affects rice growth and the environment. To understand the effect of irrigation conditions on water temperature in a paddy field, water temperature distribution under 42 different irrigation models including the use of ICT water management, which enables remote and automatic irrigation, was simulated using a physical model of heat balance. The following results were obtained: (1) Irrigation water temperature had a more significant effect on paddy water temperature close to the inlet. As the distance from the inlet increased, the water temperature converged to an equilibrium, which was determined by meteorological conditions and changes in water depth. (2) Increasing the irrigation rate with higher irrigation water amount increased the extent and magnitude of the effects of the irrigation water temperature. (3) When total irrigation water amount was the same, increasing the irrigation rate decreased the time-averaged temperature gradient effect over time across the paddy field. (4) Irrigation during the lowest and highest paddy water temperatures effectively decreased and increased the equilibrium water temperature, respectively. The results indicate that irrigation management can be used to alter and control water temperature in paddy fields, and showed the potential of ICT water management in enhancing the effect of water management in paddy fields. Our results demonstrated that a numerical simulation using a physical model for water temperature distribution is useful for revealing effective water management techniques under various irrigation methods and meteorological conditions.
Cesium-137 (137Cs) is strongly adsorbed on clay minerals, especially on illite. The adsorption of Cs+ on reference clay minerals, however, has not been fully investigated in relation to the presence of illite. The objective of this study was to clarify the effect of impurities (i.e., illite and vermiculite), present in reference smectite group minerals and kaolin minerals, on the retention of Cs+. The clay mineralogy of the reference minerals was characterized by X-ray diffraction (XRD). The radiocesium interception potential (RIP) was measured as an index of the Cs+ retention ability of clays. The content of illite in clay was represented by the total potassium (K) content given that illite is a major source of K in the clay fraction. The content of vermiculite in clay was represented by the Cs fixation capacity induced by Cs saturation followed by heating of samples at 110°C. Metabentonite and beidellite gave extremely high RIP values compared with other smectite group minerals, although a peak for illite (at 1.0 nm) was not observed in XRD analysis. The reference smectite and kaolin minerals showed a range of RIP values, even though their RIP values are theoretically zero. The RIP values had a significant positive correlation with the total K content of all the reference clay minerals (rs = 0.621*). This indicated that the retention ability for 137Cs depended more on the content of illite, as impurity, rather than the type of bulk mineral. Hence, the contribution of illite to the magnitude of the RIP was elucidated by the combination of measurement of total K content and XRD analysis. 相似文献
Effective preselection of sex has been accomplished in several species of livestock and
also in humans using the flow cytometric sperm sorting method. A guaranteed high sorting
accuracy is a key prerequisite for the widespread use of sperm sexing. The standard
validation method is flow cytometric remeasurement of the DNA content of the sexed sperm.
Since this method relies on the same instrument that produced the original sperm
separation, it is not truly independent. Therefore, to be able to specifically produce
either male or female offspring in the dog, we developed a method of direct visualization
of sex chromosomes in a single sperm using fluorescence in situ
hybridization (FISH) as a validation method. Denaturation of canine spermatozoa by
immersion in 1 M NaOH for 4 min yielded consistent hybridization results with over 97%
hybridization efficiency and a good preservation of sperm morphology. There was no
significant difference between the theoretical ratio (50:50) and the observed ratio of X-
and Y-chromosome-bearing spermatozoa in any of the three dogs. In addition, the mean
purities of flow-sorted sex chromosomes in spermatozoa of the three dogs were 90.8% for
the X chromosome fraction and 89.6% for the Y chromosome fraction. This sorting was
evaluated by using the dual color FISH protocol. Therefore, our results demonstrated that
the FISH protocol worked reliably for both unsorted and sexed sperm samples. 相似文献
Effects of supporting materials during vitrification procedure on the morphologies
of preantral follicles of pig ovaries were assessed. Ovarian cortical sections of
prepubertal pigs were randomly allocated to 5 groups. The sections were vitrified
ultrarapidly with 5 different vitrification devices. The sections were put on 4 fine
needles (Cryosupport), on a thin copper plate, or on a carbon graphite sheet or were
sandwiched between copper plates or between carbon graphite sheets before cooling.
The cooling and warming rates with the graphite sheets were significantly higher than
those with the copper plates (P<0.05). A total of 3,064 follicles were analyzed
following HE staining after vitrification with 5 different devices. The morphologies
follicles vitrified on the Cryosupport or on the graphite sheet were well preserved
compared with those vitrified on the copper plate or between copper plates
(P<0.01). The morphologies of follicles vitrified between copper plates were
mostly damaged (P<0.05). Taken together, good thermally conducting material
supports follicle morphologies of ovaries cryopreserved with ultrarapid
vitrification. 相似文献
Evaluation of a new chemiluminescent enzyme immunoassay, the PATHFAST assay system
(PATHFAST), for measurement of circulating progesterone in mares was performed. Five mares
at the mid-luteal stage were administrated a single i.m. injection of prostaglandin F2α
analog (PGF2α; cloprostenol 250 μg/ml), and then blood samples were collected from the
jugular vein at 0, 15, 30 and 45 min, at one-hour intervals until 24 and at 48 hr via a
catheter in the jugular vein. To monitor the physiological changes in circulating
progesterone in mares after induced luteolysis, concentrations of progesterone in whole
blood and serum samples were measured by PATHFAST. In addition, concentrations of
progesterone in serum samples measured by PATHFAST were compared with those measured by
radioimmunoassay (RIA) and enzyme immunoassay (EIA). Using PATHFAST, the serum
concentrations of progesterone in mares correlated highly with those of whole blood
samples (r=0.9672, n=88). The serum concentrations of progesterone as measured by PATHFAST
correlated well with RIA (r=0.9654, n=88) and EIA (r=0.9323, n=112). An abrupt decline in
circulating progesterone in whole blood samples was observed within 2 hr (50%), followed
by a gradual decline until 48 hr later. The results for progesterone in whole blood
samples correlated highly with those in serum samples, and the declining pattern
paralleled that of the serum samples. These results demonstrated that PATHFAST is useful
in the equine clinic as an accurate diagnostic tool for rapid assay of progesterone within
26 min, using unextracted whole blood. 相似文献
Based on sequences of two cosmid clones from Japanese quail (Coturnix japonica, Coja), we confirmed that the syntenic cluster, GNB2L1~BTN1~BTN2, is located in the quail TRIM subregion of the quail major histocompatibility complex (MHC Coja) region. These cosmids also included four CjBG loci and one CjLEC locus; therefore, the quail TRIM subregion was thought to be adjacent to the BG/LEC subregion. We then identified three polymorphic markers – CjHEP21, CjTRIM39.2 and CjBTN2 – in the TRIM subregion that may be useful for the functional analysis of the MHC‐Coja region. We examined MHC‐Coja sequences from 321 individual quails sampled from 11 inbred strains, and we found eight alleles for each of the three genes – CjHEP21, CjTRIM39.2 and CjBTN2. These polymorphisms represent the first avian DNA markers in the TRIM subregion. Additionally, we discovered a quail‐specific VNTR (variable number of long tandem repeats, 133–137 bp) in intron 7 of CjBTN2. We identified 25 haplotypes in the sample of 321 quail; these haplotypes comprised combinations of all 24 alleles of the three polymorphic genes. We suggest that there are two recombination hotspots, one between each pair of adjacent loci. All strains, except AMRP, contained multiple haplotypes; the AMRP strain contained a single, apparently fixed haplotype. 相似文献