3种玻璃化冷冻小鼠生发泡期卵母细胞效果比较

目的:比较3种玻璃化冷冻对小鼠生发泡期卵母细胞的存活及胚胎发育潜能的影响。方法:将小鼠生发泡期卵丘复合物(n=175、177、190)和裸卵(n=150、149、150)分别随机分为3组:采用一步乙二醇法、乙二醇加二甲基亚砜法、三步乙二醇法进行冷冻保存。解冻存活体外培养成熟后行卵胞浆内单精子显微注射受精,进一步评价胚胎发育潜能。结果:冻融小鼠生发泡期卵丘复合物,三步乙二醇法与一步乙二醇法的存活率、成熟率、受精率均高于乙二醇加二甲基亚砜组(P均<0.05);三步乙二醇法的优质胚胎和囊胚率均高于一步乙二醇法和乙二醇加二甲基亚砜法(P均<0.05)。冻融小鼠生发泡期裸卵,三步乙二醇法的存活率及三步乙二醇法、一步乙二醇法的受精率及卵裂率均高于乙二醇加二甲基亚砜法(P均<0.05)。三步乙二醇法中,卵丘复合物组的存活率、成熟率、受精率、卵裂率及优质胚胎率均高于裸卵组(P均<0.05)。结论:3种玻璃化冷冻中,三步乙二醇法可以获得高质量的冻融小鼠生发泡期卵母细胞,是一种理想的冷冻方法;带完整卵丘颗粒细胞的生发泡期卵母细胞的冻融效果更佳。

生物科学专业开设卵母细胞体外成熟实验

为了使学生更好地理解减数分裂和卵母细胞成熟过程,引入卵母细胞体外成熟实验。取青春期雌性小鼠卵巢,通过机械穿刺的方法,释放皮质区卵泡内的卵母细胞,收集生发泡期(Germinal Vesicle,GV)卵母细胞,进行成熟培养16~18 h后,观察并比较GV期、生发泡破裂期(GV Breakdown,GVBD)和MⅡ各时期卵母细胞的形态特征。收集MⅡ期卵母细胞,通过核染料Hoechst33342染核观察。荧光显微镜下排出第1极体的卵母细胞可见一大核(卵母细胞核)和一小核(极体核)。该实验项目的开设可以帮助学生更好地理解减数分裂的概念以及减数分裂Ⅰ的进程。

浅论五言诗的源流

五言诗的产生和发展经历了萌芽期、生发期和成熟期三个阶段。它起源于《诗经》和先秦民间谣谚,诞生于西汉成帝之时,成长于两汉,成熟于东汉末年的建安时期。

小鼠卵母细胞中14-3-3蛋白亚型的表达

目的对小鼠卵母细胞生发泡期(GV)、生发泡破裂期(GVBD)的14-3-3蛋白亚型表达进行鉴定。方法RT-PCR法检测GV、GVBD期卵母细胞中14-3-3蛋白7个亚型的mRNA水平,蛋白免疫印迹(Western blotting)法检测其蛋白表达水平。结果检测了7个14-3-3亚型(β,γ,ε,σ,ζ,τ和η)mRNA的表达水平,结果显示,在GV期只有14-3-3β和14-3-3ε两个亚型表达,并且14-3-3εmRNA水平显著高于14-3-3β(P<0.01)。在蛋白水平上,在小鼠卵母细胞GV期和GVBD期均检测到14-3-3ε亚型蛋白表达,未检测到14-3-3β蛋白表达。结论 14-3-3蛋白ε亚型在小鼠卵母细胞GV、GVBD期均稳定表达。

Effects of Different Intercropping Modes on Growth, Yields and Economic Benefit of Cassava and Peanut in Symbiotic Period

[Objective] This study was conducted to investigate effects of different intercropping modes on growth, yields and economic benefit of cassava and peanut in symbiotic period. [Method] With sole cropping of cassava （M1） and sole cropping of peanut （M2） as control groups, effects of intercropping of cassava with 1 row, 2 rows and 3 rows of peanut （M3, M4 and M5）on crop growth, yields and economic benefit were studied. [Result] Intercropping affected both growth and yields of cassava and peanut. Growth competition existed between cassava and peanut, and plant heights of cassava and peanut changed similarly. In late stages of intercropping, treatments M1, M2 and M5 showed higher plant heights under no nitrogen application, while treatment M3 and M4 exhibited higher plant heights under nitrogen application; intercropping improved leaf temperature, but no obvious law could be observed among different intercropping treatments; and intercropping improved total dry matter amount, which was the highest in M5 in root expanding stage and on the 30th day of the expanding stage, and the highest in M4 on the 60th day of the expanding stage. Intercropping reduced the yield of single plant, but improved the economic benefit of red upland soil; and under no nitrogen application and nitrogen application, cassava yields decreased by 25.35% and 14.55%, respectively, peanut yields decreased by 28.76% and 52.60%, respectively, while economic benefit increased by 72.90% and 56.82%, respectively. [Conclusion] Compared with sole cropping, interplanting cassava with 1 row, 2 rows or 3 rows of peanut could all improve economic benefit, and the economic benefit increased with number of rows of interplanted peanut increasing.

Screening and Evaluation of Salt Tolerant Varieties in Peanut

The selection and application of salt tolerance varieties in peanut is impor- tant for the exploitation of saline soil. In this study, 41 peanut varieties were select- ed for the evaluation of salt tolerance in both germination and young seedling stage. The results showed the germination and growth of peanut were significantly inhibited by salt stress, which were enhanced by salt concentration increasing. The 0.5% NaCI was selected as the most suitable concentration for further identification, and the characters in germination stage （including the relative germination potential, relative germination rate and germination index） and young seedling stage （including relative main root length, seedling height, fresh weight, dry weight, et aL） were measured. Cluster analysis showed the varieties could be divided into different groups, and 9 and 3 salt-tolerant varieties were identified in the two stages, respec- tively, including two varieties performed well in both two stages, which could be useful for the breeding of new salt tolerance varieties and the study of salt toler- ance mechanism.

Physio-Biochemical Changes in Jujube Fruits(Zizyphus jujuba Mill. cv. Lingwuchangzao) at Mature Stage

The changes of physiological and biochemical indices in jujube fruits during the late development were investigated from 6-year-old jujube trees （Zizyphus jujuba Mill. cv. Lingwuchangzao）. The results showed that the flesh firmness decreased slowly from white-green stage to full-red stage, being significantly related with the developmental maturity of jujube fruits negatively, the correlation coefficient reached -0.980 3^＊＊. The contents of ascorbic acid and titratable acid in jujube fruits were significantly related with the developmental process of jujube fruits negatively or positively, the correlation coef- ficients were -0. 973 1^＊＊and ＋ 0. 974 6^ ＊ ＊ , respectively. The contents of soluble solids, total sugar, and sucrose increased with jujube ripening, while the relative sweetness of jujube fruits showed the same variation pattern, the correlation coefficients were 0. 996 6 ^＊ ＊ , 0. 988 0^＊＊ , and 0. 982 8 ^＊ ＊ , respectively. Before white-green stage during fruit development, the accumulation of monosaccharide was predominant in jujube fruits, following a fast accumulation of sucrose, indicating that the main component of sugars is sucrose at the crisp-ripe stage. Furthermore, the starch content of the flesh reached the peak at about thirty percentage of jujube maturity, being 51,54 mg/100 g.FW. The respiratory rates varied between 10 mg/（ kg.h） and CO2 26 mg/（ kg.h） after fruit turning red and before softening, indicating a non-climacteric respiratory type.

Effect of a fermented milk containing Bifidobacterium lactis DN-173010 on Chinese constipated women

AIM: To investigate the effect of a fermented milk containing Bifidobacterium lactis DN-173010 and yogurt strains (BIO) on adult women with constipation in Beijing.METHODS: A total of 135 adult females with constipation were randomly allocated to consume for 2 wk either 100 g of the test fermented milk or 100 g of an acidified milk containing non-living bacteria (control).Stool frequency,defecation condition scores,stool consistency and food intake were recorded at baseline and after 1 and 2 wk in an intention-to-treat population of 126 subjects.In parallel,safety evaluation parameters were performed.RESULTS: At baseline,no differences were found between groups.Following consumption of test product,stool frequency was significantly increased after 1 wk (3.5 ± 1.5 vs 2.4 ± 0.6,P < 0.01) and 2 wk (4.1 ± 1.7 vs 2.4 ± 0.6,P < 0.01),vs baseline.Similarly,after 1 and 2 wk,of test product consumption,defecation condition (1.1 ± 0.9 vs 1.9 ± 1.2,P < 0.01 and 0.8 ± 1.0 vs 1.9 ± 1.2,P < 0.01,respectively) and stool consistency (1.0 ± 0.8 vs 1.5 ± 1.1,P < 0.01 and 0.6 ± 0.8 vs 1.5 ± 1.1,P < 0.01,respectively) were significantly improved.Compared with the control group,stool frequency was also significantly increased (3.5 ± 1.5 vs 2.5 ± 0.9,P < 0.01 and 4.1 ± 1.7 vs 2.6 ± 1.0,P < 0.01,respectively),and defecation condition (1.1 ± 0.9 vs 1.6 ± 1.1,P < 0.01 and 0.8 ± 1.0 vs 1.6 ± 1.1,P < 0.01,respectively) and stool consistency (1.0 ± 0.8 vs 1.4 ± 1.0,P < 0.05 and 0.6 ± 0.8 vs 1.3 ± 1.0,P < 0.01,respectively) significantly decreased after 1 and 2 wk of product consumption.During the same period,food intake did not change between the two groups,and safety parameters of the subjects were within normal ranges.CONCLUSION: This study suggests a beneficial effect of a fermented milk containing B.lactis DN-173010 on stool frequency,defecation condition and stool consistency in adult women with constipation constipated women after 1 and 2 wk of consumption.

Memory consolidation during sleep and adult hippocampal neurogenesis

In anticipation of the massive burden of neurodegenerative disease within super-aged societies, great efforts have been made to utilize neural stem and progenitor cells for regenerative medicine. The capacity of intrinsic neural stem and progenitor cells to regenerate damaged brain tissue remains unclear, due in part to the lack of knowledge about how these newly born neurons integrate into functional circuitry. As sizable integration of adult-born neurons naturally occurs in the dentate gyrus region of the hippocampus, clarifying the mechanisms of this process could provide insights for applying neural stem and progenitor cells in clinical settings. There is convincing evidence of functional correlations between adult-born neurons and memory consolidation and sleep; therefore, we describe some new advances that were left untouched in our recent review.

Joint Occurrence Period of Wind Speed and Wave Height Based on Both Service Term and Risk Probability

Return periods calculated for different environmental conditions are key parameters for ocean platform design.Many codes for offshore structure design give no consideration about the correlativity among multi-loads and over-estimate design values.This frequently leads to not only higher investment but also distortion of structural reliability analysis.The definition of design return period in existing codes and industry criteria in China are summarized.Then joint return periods of different ocean environmental parameters are determined from the view of service term and danger risk.Based on a bivariate equivalent maximum entropy distribution,joint design parameters are estimated for the concomitant wave height and wind speed at a site in the Bohai Sea.The calculated results show that even if the return period of each environmental factor,such as wave height or wind speed,is small,their combinations can lead to larger joint return periods.Proper design criteria for joint return period associated with concomitant environmental conditions will reduce structural size and lead to lower investment of ocean platforms for the exploitation of marginal oil field.

Developmental ecology of the American horseshoe crab Limulus polyphemus

During spawning events, horseshoe crab eggs are released from the female＇s oviducts, and fertilized by one or more males. Eggs are shaped by the female into discrete clutches deposited in nests at depths of 10-20 cm on intertidal estuarine beaches. Distinguishing between fxesh eggs and the early developmental stages is obfuscated by the large amount of dense, opaque yolk. The first unambiguous confirmation of development is the formation of the rudimentary prosomatie appendages at the ＂limb bud＂ stage. Several days thereafter, the outer chorion is shed and the developing embryo expands and undergoes a series of molts within the clear inner egg membrane. The trilobite （first iustar） stage thus attained may remain within the beach sedi- ments for several more weeks, until hatching is facilitated by environmental factors such as hydration, agitation, and osmotic shock that accompany the infiltration of seawater into the nests. Trilobites exhibit endogenous eirgatidal swimming rhythms that are entrained by mechanical agitation, suggesting that peaks in larval swimming are timed to coincide with periods of high water and the inundation of the nests. Larval swimming is limited and does not appear to result in long-distance dispersal. The limited dispersal of the larvae has important implications for the population dynamics of relatively isolated populations. The rate of larval development is highly plastic and is influenced by temperature, salinity, dissolved oxygen, and the presence of pollutants. The broad environmental tolerances of horseshoe crab embryos and larvae are important in understanding their current geographic distribution and their evolutionary persistence

Requirement for cyclin D3 in germinal center formation and function

Germinal centers （GC） of secondary lymphoid tissues are critical to mounting a high-affinity humoral immune response. B cells within the GC undergo rapid clonal expansion and selection while diversifying their antibody genes. Although it is generally believed that GC B cells employ a unique proliferative program to accommodate these processes, little is known about how the GC-associated cell cycle is orchestrated. The D-type cyclins constitute an important component of the cell cycle engine that enables the cells to respond to physiological changes. Cell type- and developmental stage-specific roles of D-type cyclins have been described but the cyclin D requirement during GC reaction has not been addressed. In this study, we report that cyclin D3 is largely dispensable for proliferation and Ig class switching of in vitro activated B cells. In contrast, GC development in Ccnd3^-/- mice is markedly impaired, as is the T cell-dependent antibody response. Within the GC, although both switched and unswitched B cells are affected by cyclin D3 inactivation, the IgM^- pool is more severely reduced. Interestingly, despite a compensatory increase in cyclln D2 expression, a significant number of Ccnd3^-/- GC B cells accumulate in quiescent GO state. Lastly, although cyclin D3 inactivation did not disrupt BCL6 expression in GC B cells, it completely blocked the GC promoting effect of BCL6 overexpression, suggesting that cyclin D3 acts downstream of BCL6 to regulate GC formation. This is the first demonstration that cyclin D3 plays an important and unique role at the GC stage of B cell development.

Inhomogeneous trends in the onset date of extreme hot days in China over the last five decades

Using a homogenized daily maximum temperature(T_(max))dataset across China,this study characterized the spatiotemporal variation of the onset date of extreme hot days in a year(i.e.,FirstEHD)during 1960-2018.Inhomogeneous trends of FirstEHD over China during 1960-2018 can be found,with the advanced trend of FirstEHD over most parts in China,while a number of stations in North-Central China(NC)show the delayed trend of FirstEHD.Moreover,there exist interdecadal changes of FirstEHD trend,with a remarkable difference in the trend magnitude before and after the 1990s over South China(SC),and the sign of trend can even reverse from negative to positive after the 1990s in Xinjiang(XJ)and Yangtze River Basin(YR),and from positive to negative in NC.The overall trends of FirstEHD over NC,YR,and XJ during 1960-2018 are dominated by the trends before the 1990s,while they are dominated by the sharp advance after the 1990s over SC.It is further found that the trend of FirstEHD can generally be explained by the long-term trend in T_(max) over most parts of China,but the contribution from T_(max) variabilities is also non-negligible and can even account for more than 75% of the overall trend over NC.The possible factors responsible for the decadal changes in FirstEHD trends are also discussed.

Life cycle assessment in the environmental impact evaluation of urbandevelopment--a case study of land readjustment project,Hyogo District, Japan

In this paper, the Life Cycle of Urban Development was firstly analyzed, and the phases of Life Cycle Assessment applied to Urban Development (ULCA) were described. As a case study, ULCA was applied in the environmental impact assessment of the land readjustment project of Hyogo District of Saga, Japan. In addition, mitigation proposals for reducing CO2 were also presented and the relevant environmental ef-fects were simulated.

Addition of hepatectomy decreases liver recurrence and leads to long survival in hilar cholangiocarcinoma

AIM： To evaluate hepatic recurrence and prognostic factors for survival in patients with surgically resected hilar cholangiocarcinoma in a single institution over the last 13 years. METHODS： From 1994 to 2007, all patients with hilar cholangiocarcinoma referred to a surgical clinic were evaluated. Demographic data, tumor characteristics, and outcome were analyzed retrospectively. Outcome was compared in patients who underwent additional liver resection with resection of the tumor. RESULTS： Of the 69 patients submitted to laparotomy for tumor resection, curative resection （Ro resection） was performed in 40 patients, and palliative resection in 29. Thirty-one patients had only duct resection, and 38 patients had combined duct resection with liver resection including 34 total or part caudate lobes. Curative rates with the combined hepatectomy were significantly improved compared with those without additional hepatectomy （27/38 vs 13/31; X^2 = 5.94, P 〈 0.05）. Concomitant liver resection was associated with a decreased incidence of initial recurrence in liver one year after surgery （11/38 vs 23/31; X^2 = 13.98, P 〈 0.01）. The 3-year survival rate after Ro resection was 30.7% and was 10.5% for palliative resection. R0 resection improved the 3-year survival rate （30.7% vs 10.5%; X^2 = 12.47, P 〈 0.01）.CONCLUSION： Hepatectomy, especially including the caudate lobe combined with bile duct resection should be considered standard treatment to cure hilar cholangiocarcinoma.

Alterations of glutathione S-transferase and matrix metalloproteinase-9 expressions are early events in esophageal carcinogenesis

AIM: To investigate the role of glutathione S-transferase (GST) and matrix metalloproteinase-9 (MMP-9) expres-sions in the development and progression of reflux es-ophagitis-Barrett’s metaplasia-dysplasia-adenocarcinoma sequence in the esophagus.METHODS: GST and MMP-9 expressions were analyzed in 51 paraffin-embedded tissue samples by immunohisto-chemistry including patients with reflux esophagitis (n = 7), Barrett’s metaplasia (n = 14), Barrett and esophagi-tis (n = 8), Barrett and dysplasia (n = 7), esophageal adenocarcinoma (n = 8) and a control group without any histological changes (n = 7). Immunostaining was determined semiquantitatively. Statistical analysis with one-way ANOVA, LSD test and correlation analysis were performed. P value of < 0.05 was considered significant.RESULTS: GST expression was significantly higher while MMP-9 expression was significantly lower in control group compared to Barrett’s metaplasia and the other groups. No major changes were observed between Bar-rett, esophagitis, and Barrett and concomitant esophagi-tis. Barrett and concomitant dysplasia, and adenocarci-noma revealed a significant lower expression of GST and higher levels of MMP-9 compared to all other groups. Adenocarcinoma showed almost no expression of GST and significantly higher levels of MMP-9 than Barrett and concomitant dysplasia. Alterations of GST and MMP-9 were inversely correlated (r = - 0.82).CONCLUSION: Decreased GST and increased ex-pression of MMP-9 in Barrett’s metaplasia-dysplasia-adenocarcinoma sequence as compared to normal tissue suggest their association with esophageal tumorigenesis. Loss of GST and gain of MMP-9 in Barrett with dyspla-sia compared to non-dysplastic metaplasia indicate that these alterations may be early events in carcinogenesis. Quantification of these parameters in Barrett’s esopha-gus might be useful to identify patients at higher risk for progression to cancer.

Effects of Elevated Seawater pCO2 on Early Development of Scallop Argopecten irradias (Lamarck, 1819)

To investigate the effects of elevated seawater p CO_2 on the early developmental stages of marine benthic calcifying organisms, we exposed the eggs and larvae of Argopecten irradias, an important bivalve species in Chinese aquaculture, in seawater equilibrated with CO_2-enriched(1000 ppm) gas mixtures. We demonstrated that elevated seawater pCO_2 significantly interfered with fertilization and larval development and resulted in an increased aberration rate. Fertilization in the treatment(pH 7.6) was 74.3% ± 3.8%, which was 9.7% lower than that in the control(p H 8.3)(84.0% ±3.0%). Hatching success decreased by 23.7%, and aberration rate increased by 30.3% under acidic condition. Larvae in acidified seawater still developed a shell during the post-embryonic phase. However, the shell length and height in the treatment were smaller than those in the control. The development of embryos differed significantly at 12 h after fertilization between the two experimental groups. Embryos developed slower in acidified seawater. Nearly half of the embryos in the control developed into D-shaped larvae at 48 h after fertilization, which were considerably more than those in the treatment(11.7%). Results suggest that future ocean acidification(OA) would cause detrimental effects on the early development of A. irradias.

Early development and the point of no return in pikeperch( Sander lucioperca L.) larvae

The objectives of the present study were to evaluate the yolk-sac and oil globule absorption and point of no return （PNR） ofpikeperch （Sander lucioperca L.） larvae. Artificial propagation ofpikeperch was performed at （15±2）℃. Yolk-sac absorption, oil globule absorption, larval growth and the first initial feeding rate were observed to analyze the early growth and to determine the PNR of pikeperch larvae. The total length of newly hatched （0 day after hatching, DAH） pikeperch larvae was （4.25±0.22） mm and the volume of the yolk-sac and the oil globule was （0.30±0.12）mm^3 and （5.14±2.28） 10-2 mm^3 respectively. The yolk-sac and the oil globule were exhausted at 11 DAH and 14 DAH, respectively. Pikeperch larvae began feeding at 8 DAH with an initial feeding rate about 10.0%. From 9 to 14 DAH, the initial feeding rate increased rapidly, and reached its highest （about 82.7%） at 14 DAH. It declined thereafter, 48.9% at 15 DAH and 35.6% at 16 DAH, thus the pikeperch larvae reached PNR by 15-16 DAH. The appropriate first feeding time for the pikeperch larvae is 11-12 DAH, when the initial feeding rate is higher than half of the maximum initial feeding rate.

Radiofrequency ablation of recurrent cholangiocarcinoma after orthotopic liver transplantation—a case report

AIM: To report the use of radiofrequency ablation in the treatment of recurrenct cholangiocarcinoma in the transplanted liver.METHODS: A lady who underwent orthotopic liver transplantation (OLT) for intrahepatic cholangiocarcinoma recurrence of tumour 13 mo after tralsplantation inspite of adjuvant chemotherapy. Her recurrent tumour was treated with radiofrequency ablation.RESULTS: She survived for 18 mo following the recurrence of her tumour.CONCLUSION: Radiofrequency ablation can be used safely in the transplanted liver to treat recurrent tumour.

Longevity,Capital Formation and Economic Development

Many researchers have concluded that longer life expectancies prompt increased investment in education,as a prolonged labor supply raises the rate of return on education.Besides explaining the empirical evidence behind this conclusion(at an absolute level),there is another issue to be discussed:does time spent studying and working increase proportionally with higher longevity? Building on an extended life-cycle model,this paper shows that prolonged life expectancy will cause individuals to increase their time in education but may not warrant rises in labor input.Later we show that higher improvement rate of longevity rather than initial life expectancy will promote economic growth,even we exclude the mechanism of human capital formation,and only consider growth effects of higher improvement rate of life expectancy from physical capital investment.