Different aggregation properties of sea urchin embryonic cells at different developmental stages. II. Stage specific response to fibronectin and collagen

Fibronectin and collagen were added to cells dissociated from embryos at the blastula and at the 16 cell stages. Both molecules stimulate aggregation of cells dissociated from blastula but they do not affect aggregation of blastomeres dissociated from the 16 cell stage. The stage-specific response to fibronectin and collagen appears to be related to the onset of new functional role(s) of the two molecules at the blastula stage.     

Erythropoiesis in the fetal trisomy 19 mouse. I. Characterization of erythrocyte populations in peripheral blood

Changes in the type, size, and relative percentage of different erythrocyte populations in the peripheral blood of individual trisomy 19 and normal littermate mouse fetuses were studied from 12 gestational days to term. Large nucleated erythrocytes of yolk-sac origin comprise the first population of cells and are gradually diluted out of the circulation by nonnucleated erythrocytes of hepatic origin. This transition occurs between 12 and 16 gestational days. The rate of decline of the nucleated erythrocytes in the trisomic animals lagged by approximately 1 day behind the normal littermates, so that they did not completely disappear from the peripheral circulation until day 17. A slight decrease in size of the nonnucleated erythrocytes which occurs with increasing gestational age was also delayed by approximately 1 day in the trisomic fetuses. These observations are consistent with an hypothesis that one effect of the murine trisomy 19 genome is to retard by 1 day the growth and development of the affected animal.     

Epidermal growth factor potentiates cortisone-induced cleft palate in the mouse.

Epidermal growth factor (EGF) injected into pregnant mice increased the frequency of cleft palate (CP) in cortisone-treated mouse fetuses. EGF alone produced proliferation and thickening of the epithelium of the palatal processes, but CP was not significantly increased over saline injected controls. Cortisone alone produced thinning of the palatal epithelium and caused CP in 61 percent of formed fetuses. The combination of EGF and cortisone treatment induced CP in 100 percent of formed fetuses; epithelial thickening still occurred with the combination treatment. Thus, EGF may be teratogenic under special circumstances. These observations suggest that the relative thickness of the palatal shelf epithelium may not be a critical factor in the fusion of the palatal shelves.     

The porcine ovarian follicle: I. Selected chemical analysis of follicular fluid at different developmental stages.

Numerous parameters of the chemical composition of porcine follicular fluid, obtained at different stages of follicle development, were analyzed. The concentrations of electrolytes, glucose, uric acid, selected enzymes, lipids, amino acids, cyclic AMP, and steroid hormones were determined and compared with concentrations in serum. There were both quantitative and qualitative differences in the composition of follicular fluid and plasma. These differences are discussed with regard to follicular development.     

Enzyme patterns in trisomy 19 of the mouse

Activity patterns of cytosolic and mitochondrial enzymes of carbohydrate and amino acid metabolism have been measured in murine trisomy 19. In spite of marked hypoplasia, no significant alterations of the patterns (per gram of organ weight) were observed, with the exception of glutamate oxaloacetate transaminase (GOT-1), and phosphoglycerate mutase (PGAM). Clear-cut gene dosage effects in liver, brain, heart, skeletal muscle, and erythrocytes of fetal and newborn mice, confirm the assignment of GOT-1 to chromosome 19. Data obtained for PGAM demonstrate that one of the two different subunits leading to organ-specific isozyme patterns of the dimer enzyme protein is coded on chromosome 19 (gene Pgam-1). Dosage effects are fully expressed in liver, brain, and erythrocytes (AA-type isozyme), but not in skeletal muscle (BB-type isozyme). Dosage effects on the hybrid AA-AB-BB-isozyme pattern in the course of development of the heart muscle, were demonstrated by means of quantitative activity measurement after electrophoretic separation. The comparison of enzyme patterns of eusomic and trisomic erythrocytes, produced after injection of fetal stem cells into irradiated adult carriers (transplantation chimaeras), revealed enzyme activity ratios that were similar to those produced by erythrocytes of adult euploid and trisomic mice. This is in agreement with the chromosome assignments and dosage effects mentioned above.     

Two-dimensional protein maps of xenopus eggs and embryos at different developmental stages.

Protein expression during the early development of Xenopus has been followed by 2D-polyacrylamide gel electrophoresis (PAGE). The analysis of two-dimensional maps of eggs and embryos at different stages of development has allowed the separation of more than 2000 spots. Identification of numerous polypeptides was obtained in four different ways: (1) immuno-blotting; (2) amino terminal sequence after blotting on to PVDF membranes; (3) comigration; and (4) assignment in comparison with proteins separated by 2D techniques on reference maps such as human liver, red blood cells, plasma and cerebrospinal fluid reported in the Swiss 2D-PAGE Data Base. The maps presented in this report are a step toward the study of the protein expression in Xenopus eggs and embryos and may be a powerful working tool since Xenopus embryos are popular models for the study of development.     

Changes in the magnitude and distribution of forces at different Dictyostelium developmental stages

The distribution of forces exerted by migrating Dictyostelium amebae at different developmental stages was measured using traction force microscopy. By using very soft polyacrylamide substrates with a high fluorescent bead density, we could measure stresses as small as 30 Pa. Remarkable differences exist both in term of the magnitude and distribution of forces in the course of development. In the vegetative state, cells present cyclic changes in term of speed and shape between an elongated form and a more rounded one. The forces are larger in this first state, especially when they are symmetrically distributed at the front and rear edge of the cell. Elongated vegetative cells can also present a front-rear asymmetric force distribution with the largest forces in the crescent-shaped rear of the cell (uropod). Pre-aggregating cells, once polarized, only present this last kind of asymmetric distribution with the largest forces in the uropod. Except for speed, no cycle is observed. Neither the force distribution of pre-aggregating cells nor their overall magnitude are modified during chemotaxis, the later being similar to the one of vegetative cells (F(0) approximately 6 nN). On the contrary, both the force distribution and overall magnitude is modified for the fast moving aggregating cells. In particular, these highly elongated cells exert lower forces (F(0) approximately 3 nN). The location of the largest forces in the various stages of the development is consistent with the myosin II localization described in the literature for Dictyostelium (Yumura et al.,1984. J Cell Biol 99:894-899) and is confirmed by preliminary experiments using a GFP-myosin Dictyostelium strain.     

Study of the mechanisms of BUdR-induced cleft palate in the mouse

This study was designed to examine the pathogenesis of bromodeoxyuridine (BUdR)-induced clefts of the secondary palate in the LACA mouse. Intraperitoneal injections of BUdR (500 mg/kg body weight) were given at various days and combinations of days between E11 and E15 (plug day = E1). Treatment on E11 alone resulted in approximately 22% of fetuses with cleft palate when the latter were examined either on E16 or E19. Treatment on E11 and E12 approximately doubled the above incidence, and treatment on E11, 12 and 13 raised it to 100%. However, no treatment, either single or multiple, caused cleft palate when given later than E11. This suggests that the cellular changes caused by BUdR that lead to cleft palate must be inflicted during E11 and that such damage can be repaired in about 80% of embryos. All fetuses with cleft palate had severe micrognathia on E16 and E19, which skeletal staining showed to be the result of a bilateral sigmoid buckling of Meckel's cartilage. Studies with the scanning electron microscope (SEM) on E15, 16, and 19 suggested strongly that the micrognathia caused a relative macroglossia and hence mechanical interference with palatal shelf reorientation. Histological studies with the light microscope showed that BUdR caused cellular necrosis in many embryonic tissues during the 24 hours after its administration. This necrosis was strikingly more severe in the mandibular rudiment of the first branchial arch than in the maxillary. The latter observation accords well with findings by other workers that cell proliferation is more rapid in the mandibular blastema than in the maxillary. Transmission electron microscope (TEM) studies of the buckled region of Meckel's cartilage failed to reveal any ultrastructural differences from control Meckel's cartilage. Hence BUdR had only interfered with the shape of the cartilage but not with its histiogenesis. We conclude that BUdR, by its cytotoxicity or antidifferentiative effects, interfered with the formation of the anterior end of Meckel's cartilage, initiating a chain of events leading through micrognathia and relative macroglossia to failure of palatal shelf reorientation and cleft palate.     

Genetic independence of the embryonic reactivity difference to cortisone- and 6-aminonicotinamide-induced cleft palate in the mouse.

The A/J strain of mice is more reactive than C57BL/6J to both cortisone- and 6-aminonicotinamide-induced cleft palate. A breeding study was set up to determine the genetic control of the differences in embryonic reactivity between the two strains to the two teratogens. In this paper the test for possible association between the two response traits is presented. In the second-backcross generation of embryos where segregation of the two traits could be studied no association was found. Therefore, any embryonic genes making major contributions to differences in reactivity between the two strains are not the same for the two teratogens.     

不同发育期诸氏鲻虾虎鱼对钻井液的敏感性比较

目的筛选试验鱼适宜急性毒性试验的发育期。方法将诸氏鲻虾虎鱼早期仔鱼、中期仔鱼、晚期仔鱼、稚鱼、幼鱼及成鱼暴露于一定浓度的钻井液中,比较钻井液对不同发育期诸氏鲻虾虎鱼的急性毒性。结果早期仔鱼48 h LC50为157 mg/L,中期仔鱼48 h LC50大于500 mg/L;中期仔鱼96 h LC50为79 mg/L,晚期仔鱼96h LC50为625 mg/L,稚鱼、幼鱼、成鱼96 h LC50显著大于500 mg/L;卤虫无节幼体96 h LC50为105 mg/L;不同发育期诸氏鲻虾虎鱼对钻井液的敏感性顺序为：早期仔鱼〉中期仔鱼〉晚期仔鱼〉稚、幼、成鱼。结论诸氏鲻虾虎鱼的早期仔鱼适用于海洋污染物急性毒性评价。     

Brain and pituitary beta-endorphin levels at different developmental stages of the rat

beta-Endorphin-like immunoreactivity in whole brains of Sprague-Dawley rat fetuses of different gestational ages was measured by radioimmunoassay and found to increase throughout the gestational period studied. The immunoreactivity in various brain parts (forebrain, midbrain, hindbrain, hypothalamus and pituitary) of late prenatal, early postnatal, young mature and retired breeder rats was also determined. In all the brain parts studied, a maximum in the content and concentration of beta-endorphin-like immunoreactivity was attained when the rats were about 3-4 months old.     

Genetics of cleft lip and cleft palate in China.

During the past 10 years, 60 cases of cleft lip with or without cleft palate [CL(P)] were recorded among 45,072 newborns at Shanghai International Peace Maternity and Infant Hospital, China. The incidence was 1.33 per 1,000 births. The family histories of 163 CL(P) patients were analyzed. The incidences of CL(P) in the first-, second-, and third-degree relatives of CL(P) patients were 11/246 (4.47%), 10/1,032 (0.97%), and 6/1,727 (0.35%), respectively. Of the 163 probands, three had a history of consanguinity of the parents (1.8%), in contrast to 0.77% in the general population. These data are suggestive of multifactorial inheritance. The heritability of CL(P) in our study calculated by Falconer's formula was 77.6%.     

不同发育阶段的斑腿树蛙蝌蚪对敌敌畏遗传毒性的敏感性

敌敌畏是我国农田中使用最普遍的有机磷杀虫剂,它通过干扰对神经传导起重要作用的胆碱酯酶的活性,起到接触和摄入毒杀昆虫的作用,也对当地水生动物及种群造成很大威胁。本文以广泛分布于我国南方农田区域的斑腿树蛙蝌蚪为研究对象,用碱性单细胞电泳方法比较了暴露于不同浓度(2.08,4.16,6.24,8.32,10.40mg/L)的敌敌畏溶液中三个发育阶段的遗传毒性的差异。结果表明:敌敌畏溶液暴露24h,对早期和中期阶段的蝌蚪造成极显著的DNA损伤(P<0.01),甚至在敌敌畏浓度低达2.08mg/L的溶液中也产生显著的损伤(P<0.05);统计分析表明,DNA长宽比率与敌敌畏剂量之间呈显著的线性关系,早期阶段和中期阶段的相关系数分别为0.950(P<0.01)和0.954(P<0.01)。对于后期阶段的蝌蚪,所有浓度的敌敌畏溶液都未导致明显的DNA损伤,作者认为进入变态阶段的蝌蚪对敌敌畏的敏感性明显下降。结果同时也表明,早期和中期阶段的斑腿树蛙蝌蝌是一种监测环境遗传毒性的合适指示生物。     

Cell wall composition in the ascomycete sphaerostilbe repens at different developmental stages

Changes in the biochemical composition of isolated cell walls were analysed during the differentiation of coremia and rhizomorphs in Sphaerostilbe repens.Differentiation was accompanied by exclusively quantitative variations of the wall components: the content in carbohydrates, chitin and free amino sugars increased; on the contrary, amino acids, uronic acids, lipids and mineral substances decreased.Carbohydrates were composed of glucose, galactose and mannose; glucosamine was the main component of amino sugars. The predominant amino acid in the walls was cysteine the amount of which increased during hyphal aggregation, while quantities of the sixteen other determined amino acids decreased.Mineral matter was present in large quantities in the walls of the fungus, especially in vegetative mycelium. Iron, phosphorus and calcium were the most abundant elements.Possible relations between the variations in chemical composition of the wall and the capability of hyphae to aggregate are discussed.     

Carbon storage and fluxes in ponderosa pine forests at different developmental stages

We compared carbon storage and fluxes in young and old ponderosa pine stands in Oregon, including plant and soil storage, net primary productivity, respiration fluxes, eddy flux estimates of net ecosystem exchange (NEE), and Biome‐BGC simulations of fluxes. The young forest (Y site) was previously an old‐growth ponderosa pine forest that had been clearcut in 1978, and the old forest (O site), which has never been logged, consists of two primary age classes (50 and 250 years old). Total ecosystem carbon content (vegetation, detritus and soil) of the O forest was about twice that of the Y site (21 vs. 10 kg C m^?2 ground), and significantly more of the total is stored in living vegetation at the O site (61% vs. 15%). Ecosystem respiration (R_e) was higher at the O site (1014 vs. 835 g C m^?2 year^?1), and it was largely from soils at both sites (77% of R_e). The biological data show that above‐ground net primary productivity (ANPP), NPP and net ecosystem production (NEP) were greater at the O site than the Y site. Monte Carlo estimates of NEP show that the young site is a source of CO₂ to the atmosphere, and is significantly lower than NEP(O) by c. 100 g C m^?2 year^?1. Eddy covariance measurements also show that the O site was a stronger sink for CO₂ than the Y site. Across a 15‐km swath in the region, ANPP ranged from 76 g C m^?2 year^?1 at the Y site to 236 g C m^?2 year^?1 (overall mean 158 ± 14 g C m^?2 year^?1). The lowest ANPP values were for the youngest and oldest stands, but there was a large range of ANPP for mature stands. Carbon, water and nitrogen cycle simulations with the Biome‐BGC model suggest that disturbance type and frequency, time since disturbance, age‐dependent changes in below‐ground allocation, and increasing atmospheric concentration of CO₂ all exert significant control on the net ecosystem exchange of carbon at the two sites. Model estimates of major carbon flux components agree with budget‐based observations to within ± 20%, with larger differences for NEP and for several storage terms. Simulations showed the period of regrowth required to replace carbon lost during and after a stand‐replacing fire (O) or a clearcut (Y) to be between 50 and 100 years. In both cases, simulations showed a shift from net carbon source to net sink (on an annual basis) 10–20 years after disturbance. These results suggest that the net ecosystem production of young stands may be low because heterotrophic respiration, particularly from soils, is higher than the NPP of the regrowth. The amount of carbon stored in long‐term pools (biomass and soils) in addition to short‐term fluxes has important implications for management of forests in the Pacific North‐west for carbon sequestration.