半夏蛋白的抗兔胚泡着床作用

半夏蛋白有很强的抗兔胚泡着床作用,子宫内注射500μg,抗着床率达100%。经半夏蛋白作用后的子宫内膜能使被移植的正常胚泡不着床。在子宫内经半夏蛋白孵育的胚泡移植到同步的假孕子宫,着床率随孵育时间延长而降低。用辣根过氧化物酶标记半夏蛋白的定位实验表明该蛋白结合在子宫内膜腺管的上皮细胞膜上。已知半夏蛋白有类似凝集素的活性,能与甘露聚糖结合,它的抗着床作用可能是由于该蛋白结合了母体和(或)子体细胞膜上的某些糖结构,改变了细胞膜的生物学行为所致。     

Xylem exudate yield from detopped maize plants as an estimator of root pruning

Current methods of studying roots are either labour intensive or require expensive equipment. In 1986 and 1987 root pruning treatments were given to maize plants grown indoors. In both years the amount of xylem exudate collected from plant stumps shortly after root pruning increased with the dry weight of roots attached to the plant. The measurement of xylem exudation is presented as an alternative for conventional laborious root-study methods.     

Uterine specific antigens in the ewe

Uterine flushings from ewes on days 0, 3, 6, 9, 12 and 15 of the estrous cycle were analyzed for total protein content. Flushings from days 9, 12 and 15 had greater (P<.01) amounts of protein than those from 0, 3 and 6. Antisera to uterine fluids from ewes at day 10 to 12 or day 14 to 15 of pregnancy detected two uterine-specific antigens in uterine flushings at day 7, 11 and 15 but not at days 0 and 3 of the cycle. A third uterine antigen was also detected in kidney tissue extracts. All three antigens were present in endometrial extracts at each stage examined. Progesterone, or estrogen plus progesterone, administration to ovariectomized ewes induced the appearance of the two uterine-specific antigens. The third antigen was detectable even in ovariectomized ewes. No pregnancy-specific antigens were detected in flushings from days 7, 11 or 15 of gestation. The effect of pregnancy on endometrial protein synthesis was examined in vitro . No differences were seen in the incorporation of (3)H-leucine in day 11 pregnant or nonpregnant or in day 14 pregnant or nonpregnant endometrium. No differences in total uterine lumenal protein were observed. Endometrial secretions, obtained by conditioning media with endometrial explant cultures, were evaluated to assess their effect on protein synthesis in day 11 embryos cultured in vitro . No significant effects of endometrial secretions or serum were observed.     

Inhibitory action of estradiol on growth promoting activity in extract from uterine cancers

Extracts from uterine cervical and body cancers, but not from benign tumor or intact tissues tested, were found to contain a growth-promoting activity which induced the proliferation of human endometrial fibroblasts. Exposure of cultured fibroblasts to the cancer extracts increased the rate of [³H]thymidine incorporation in a dose-dependent manner. The activity was heat-labile, and not inactivated by removal of lipid-soluble material suggesting that the activity is associated with a protein. When the fibroblasts were preincubated with estradiol for 12 hours, but not for 1 hour, the extract-induced fibroblast proliferation was suppressed. The inhibitory effect of estradiol was dose related (EC₅₀: 10 nM) and non-competitive, suggesting that the steroid may reduce the sensitivity of fibroblasts to the extracts. This is the first report to provide direct evidence that estradiol may play an inhibitory role in the action of growth factor-like peptide produced from malignant tumors.     

Immunological characterization of soluble peroxidases from rat tissues including preputial gland

A highly active soluble peroxidase has been identified in the preputial gland of rats and characterized immunologically along with other soluble peroxidases of a number of rat tissues such as submaxillary gland, exorbital lacrimal gland and also of the uterine fluid of the estrogen treated rats. All these peroxidases have the native molecular weight around 73K as determined by gel filtration on Sephadex G-150. An antiserum raised against the pure bovine lactoperoxidase interacts with all these soluble peroxidases and immunoprecipitates the enzyme activity in a similar fashion when titrated against varied concentration of the antiserum. Following electrophoretic transfer to nitrocellulose by Western blotting, the antiserum crossreacts with the preputial, submaxillary and lacrimal gland protein of molecular weight around 73K and with the uterine fluid protein of molecular weight of 80K. An additional crossreacting protein of molecular weight of 80K is also evident in the lacrimal gland. All these enzyme preparations, however, contain another immunoreactive protein of molecular weight of about 64K. While 73–80K molecular weight interacting proteins may represent different forms of peroxidase, presumably with varied carbohydrate moieties, 64K molecular weight protein may be a precursor of the peroxidase which after posttranslational modification such as heme conjugation and glycosylation leads to formation of native enzyme. Rat harderian gland, unlike bovine origin, does not contain any detectable peroxidase activity. The immunoblot does not show the presence of any immunoreactive protein around 73K except the 64K molecular weight protein indicating that this gland can not synthesize the native peroxidase from this precursor probably due to some block in posttranslational modification.     

Effects of induced ovulation by pregnant mare's serum and human chorionic gonadotropin on the sex ratio of mouse fetuses

The sex ratio of the fetuses from mice treated with pregnant mare's serum (PMS)/human chorionic gonadotropin (HCG) to induce ovulation did not differ appreciably from that of spontaneously ovulated controls. Rather, an intriguing observation was that the sex ratio in the right uterine horns tended to be lower than that in the left horns in both spontaneously ovulated controls and PMS/HCG-treated groups. We speculate on its possible relation to the observed right-left asymmetry of horn sizes (number of fetuses in the horn).     

Influence of uterine secretions on the chromatin of ram spermatozoa at different stages of maturation: Cytophotometric study of Feulgen-DNA after in vitro incubation

Ram spermatozoa taken from the epididymal head, body, or tail or from the ejaculate were examined by microspectrometry after incubation in vitro with ewe uterine fluids at 37°C for 20 hours. Compared with incubation in Ringer's solution, uterine fluid incubation resulted in a decrease in nuclear Feulgen-DNA content. This decrease was greater for more immature spermatozoa (29.0 and 47.3% for spermatozoa from head and body, respectively) than for more mature spermatozoa (17.7 and 4.0% for spermatozoa from the tail and the ejaculate, respectively). In parallel with this decrease, there was a condensation of the chromatin which resulted in a decreased nuclear surface area, especially in spermatozoa taken from the epididymal body. Therefore, it would appear that, during epididymal maturation, changes in the ability of spermatozoa to maintain embryonic development as the spermatozoa mature are due to changes in chromatin structure.     

Cytoskeletal and contractile proteins in coelomic oocytes,unfertilized and fertilized eggs of discoglossus pictus (Anura)

The distribution of actin, myosin, and tubulin has been investigated in coelomic oocytes, unfertilized and fertilized eggs of Discoglossus pictus utilizing: (1) immunofluorescence; (2) electron microscopy; (3) incubation with heavy meromyosin (HMM), and (4) SDS-polyacrylamide gel electrophoresis (PAGE). In coelomic oocytes, the germinative area (GA) has long, irregular microvilli containing microfilaments. In the rest of the oocyte, the microvilli are shallow. During the transit of the oocyte in the oviduct, a dimple forms by the invagination of the GA. A palisade of microfialment bundles is present in the finger-shaped microvilli of the dimple and extends for about 10 μm in the cytoplasm. In the rest of the egg, microvilli are absent and only random filaments appear in the cortex. Following HMM incubation, the dimple microfilaments are decorated with arrowheads pointing toward the bulk of the cytoplasm. SDS-PAGE of egg extracts shows bands co-migrating with actin (43K), pyruvate kinase (57K), and phosphorylase (94K). As result fertilization, the pattern of microfilament bundles in the dimple disappers in parallel with the dimple invergination itself. Generally, the entire oocyte cortex is positive to immunofluorescent staining with anti-actin, antimyosin, and antitubulin antibodies. However, the pattern of distribution and intensity of immunofluorescent staining changes for each antiserum, during different stages. It is concluded that a contractile system is present in Discoglossus eggs, and it is particularly developed in the dimple. The dimple is probably a major compartment for the storage of unpolymerized tubulin.     

Effects of a larval antipredator response and larval diet on adult phenotype in an aposematic ladybird beetle

Many ladybird beetles respond to a potential predation event by `reflex bleeding' or secreting a noxious defensive chemical that is similar to hemolymph. Both adults and larvae show this response. Reflex bleeding is known to reduce predator attack rates and increase prey survival after an attack, especially when reflex bleeding is employed in combination with other cues such as odor and warning coloration. In this experiment, we examined how variability in the number of reflex bleeding events and food quality in the larval stage of the aposematic ladybird beetle Harmonia axyridis affected elytral color, development time, and terminal size in adults. Effects of reflex bleeding were subtle and may have been influenced by diet treatments. Adult color did not differ between bleed treatment groups but beetles that reflex bled tended to take longer to develop and grow to smaller sizes than control group beetles. There were clear and strong effects of larval diet on adult phenotype: an ad libitum pollen diet resulted in paler adult coloration, shorter development time, and larger adult size relative to a limited-availability aphid diet. Our results suggest that the best environment for producing bright-red coloration may not be the best environment for favorable expression of life history characters, especially under stressful conditions. Interactions between different life history stages of H. axyridis are also discussed. Received: 20 April 1997 / Accepted: 30 September 1997