冻结猪肉解冻措施筛选及优化

为了较好地保持冻结猪肉解冻后的品质,对冻结猪肉采用空气解冻、超声波解冻和微波解冻处理,研究其对解冻猪肉品质的影响,并对较好的解冻方法进行工艺优化。研究结果表明:3种解冻方法中,微波解冻能较好地保持解冻猪肉的品质。对微波工艺进行温度和间歇时间的优化,结果显示采用25℃微波解冻处理10 m in后间歇10 m in交替进行的解冻方法较好。     

胶原合成介导的软骨细胞的光生物调节作用

目的:了解低强度激光照射对软骨细胞增殖的影响及其机制。方法:选取3周龄新西兰白兔分离培养软骨细胞,在2.5%新生牛血清中培养,用半导体激光(650 nm,2.96 mW/cm2)(sem iconductor laser irrad iation,SLI)照第4代软骨细胞,每天分别照射1 m in、3 m in、5 m in、7 m in、10 m in、20 m in,共6 d。收集激光照射后第2 d、4 d、6 d、8 d、10 d和12 d的细胞培养液,用氯胺T消化法检测羟脯氨酸(H rp)的含量。在培养至第13 d时,用XTT法检测细胞的活性,了解细胞的增殖情况。结果:在2.5%新生牛血清中,SLI对软骨细胞具有明显的光生物调节作用:(1)在培养至第13 d时,所有剂量组在照射后XTT吸光度值均有不同程度的增高,其中3 m in、5 m in、7 m in和10 m in组的增高较为明显(P<0.01);(2)两因素重复测定资料的方差分析结果显示,SLI照射后软骨细胞合成胶原的能力在逐步增加,而对照组在培养至第2周开始H rp含量明显下降。结论:SLI照射可促进2.5%新生牛血清中兔软骨细胞增殖,这个过程可能是通过促进胶原合成实现的。     

激光诱变在热稳定植酸酶筛选中的应用

应用1.06μm、0.53μm与1.06μm 0.53μm波长的高重复率Nd:YAG激光器,以连续式和脉冲式辐照方式对产植酸酶的黑曲霉(Aspergillus niger)进行诱变。统计诱变结果,比较正变率×正变辐度积数后确定:连续式诱变效果优于脉冲式;在连续式中,1.06μm激光诱变效果较显著,以辐照功率15 W,辐照时间1 m in最佳;0.53μm激光应适当提高诱变时间;在脉冲式中,1.06μm波长激光辐照效果较佳,脉冲次数以100~200为宜。筛选出一株变异菌株,所产植酸酶具有一定热稳定性,高温对其酶活影响有所下降,80℃保温10 m in剩余酶活44%。     

安徽短缝藻属一新种

Valvis arcuatis, 27—35 μm longis, 11—13 μm latis, margine ventrali distincte conca-vo, dorsuali medio valde convexo, projectura deltoidea, apicibus valvae capitatis vel sub-truncto-capitatis; striis transversis in medio valvae subradiatis, 11—13 in 10 μm, sed apical-ibus parallelis vel curvatis, 14—17 in 10 μm; striis intra marginem dorsualem paucis bre-     

N~6 -methyl-adenosine (m ~6A) in RNA: An Old Modification with A Novel Epigenetic Function

N6 -methyl-adenosine (m6A) is one of the most common and abundant modifications on RNA molecules present in eukaryotes. However, the biological significance of m6A methylation remains largely unknown. Several independent lines of evidence suggest that the dynamic regulation of m6A may have a profound impact on gene expression regulation. The m6A modification is catalyzed by an unidentified methyltransferase complex containing at least one subunit methyltransferase like 3 (METTL3). m6A modification on messenger RNAs (mRNAs) mainly occurs in the exonic regions and 3’-untranslated region (3’-UTR) as revealed by high-throughput m6A-seq. One significant advance in m6A research is the recent discovery of the first two m6A RNA demethylases fat mass and obesity-associated (FTO) gene and ALKBH5, which catalyze m6A demethylation in an a-ketoglutarate (a-KG)-and Fe2+-dependent manner. Recent studies in model organisms demonstrate that METTL3, FTO and ALKBH5 play important roles in many biological processes, ranging from development and metabolism to fertility. Moreover, perturbation of activities of these enzymes leads to the disturbed expression of thousands of genes at the cellular level, implicating a regulatory role of m6A in RNA metabolism. Given the vital roles of DNA and histone methylations in epigenetic regulation of basic life processes in mammals, the dynamic and reversible chemical m6A modification on RNA may also serve as a novel epigenetic marker of profound biological significances.     

The filling phase of Mazvikadei Reservoir,Zimbabwe

Limnological measurements during the first year of filling of the newly formed Mazvikadei Reservoir in Zimbabwe showed variations in dissolved oxygen as well as soluble forms of phosphorus and nitrogen. The ratios of calcium to other major cations were: Ca:Mg = 0.38, Ca:Na = 0.50 and Ca:K = 2.0. The low Ca:Mg ratio may suppress development of mollusc populations, thus keeping the reservoir snail free. Conductivity was 160 μScm^-1. Daytime pH was 6.95–7.8. The water was dark-brown in colour, 90% of incident light was attenuated in the top 0.75 m in May, and in the top 3.5 m in August. Positive net photosynthesis was only recorded above a depth of 0.1 m, at 0.5 m and 1.0 m depths, it was negative. Zooplankton consisted of nine rotifer, four cladoceran, two cyclopoid and one calanoid species.     

石蜡油对离子注入动物细胞真空环境的保护效应初探

利用石蜡油的高效护水功能进行动物细胞(HeLa细胞)的真空及注入保护,研究了不同的预处理时间对细胞活性的影响,并将石蜡油浸泡细胞2 m in~6 m in选为最佳保护时间。当细胞经过2 m in~6 m in的预处理后再进行真空、注入,结果显示成活率大幅度提高。     

104名藏族志愿者中细胞色素P450 2C19m1的基因多态性

细胞色素P450 2C19（CYP2C19）参与临床上许多重要药物的代谢。根据其代谢S－美芬妥英或其他CYP2C19底物的能力不同,有强代谢者（EMs）和弱代谢者（PMs）之分。PMs表型的频发率存在明显的种族差异。在本文中,我们主要报道了细胞色素P450 2C19 m1在中国藏族人群中的多态性分布。在104例无血缘关系藏族人群中,49人（47.1%）为CYP2C19野生型纯合子（wt/wt）,46人（44.2%）为CYP2C19m1杂合子（wt/m1）,9人（8.7%）为CYP2C19m1突变型纯合子（m1/m1）。CYP2C19野生型等位基因频率为0.692,CYP2C19m1等位基因频率为0.308。该结果与国内外报道的中国其余民族的CYP2C19m1等位基因频率相比具有一定可比性。 关键词：细胞色素P450 2C19;基因型;藏族;聚合酶链反应;限制性内切核酸酶片段长度多态（RFLP）Abstract: Cytochrome P 450 2C19（CYP2C19） is involved in the metabolism of a number of clinically used drugs. Individuals can be characterized as extensive metabolizers （EMs）or poor metabolizers（PMs）, according to the drugs-metabolized ability of CYP2C19 in population studies. The incidence of poor metabolizer phenotype shows marked interracial differences. In this article we report the gene polymorphism of CYP2C19 in Zang population. There were 49 wild-type homozygotes（wt/wt）, 46 were heterozygotes（wt/m1） and 9 were homozygotes（m1/m1） among 104 unrelated Zang subjects. The frequency of CYP2C19m1 allele was 0.308, which was in agreement with that in other published data.     

Seasonal variations in phytoplankton size structure in Lake Cromwell (Laurentian Shield), Quebec

Seasonal variation in phytoplankton size classes was studied over the period of a year in a small, mesotrophic, brown-water lake. Throughout the sampling period, species from 2–16 μm (GALD) dominated the phytoplankten community. Small phytoplankters (2–8 μm) were predominant in winter and early spring populations while algae of 8–16 μm became important in summer (phytoplankton < 2 μm was not counted). Principal coordinate analysis resulted in a cyclic pattern of dates in the reduced space, winter and early spring samples being well separated from the other dates. In multiple linear regressions between environmental parameters and size classes, temperature was always the most important variable.     

不同海拔下全程覆膜对烤烟光合功能和产量、质量的影响

以烤烟"云烟87"为材料,研究了在湖北省恩施州2种海拔下(1000、1300 m),全程覆膜和团棵期揭膜培土2种措施对烤烟光合功能和产量、质量的影响.结果表明:在2个海拔下,全程覆膜均会在烟株生育后期引起净光合速率和叶绿素含量快速下降,加速了光合功能的衰退,从而导致光合同化物分解加速;在海拔1000 m处,团棵期揭膜培土措施提高了烤烟总体光合功能,增加光合同化产物,明显提高产量和品质;在海拔1300 m处,虽然全程覆膜有早衰现象发生,但总体光合功能及其同化产物含量仍处于较高水平;在本试验条件下,在海拔1000 m处提倡采用团棵期揭膜培土的措施,在海拔1300 m处提倡采用全程覆膜的生产措施.

Abstract：

Field experiments were conducted at the elevations 1000 m and 1300 m in Enshi Autonomous Prefecture of Hubei to study the effects of plastic film mulching in whole growth period and of uncovering plastic film and hilling at rosette stage on the photosynthetic function,yield,and quality of flue-cured tobacco Yunyan 87.At the two elevations,plastic film mulching in whole growth period caused a rapid decrease of net photosynthetic rate and leaf chlorophyll content at the later growth stages of tobacco,and thus,accelcrated the decline of photosynthetic function,and induced the rapid decomposition of assimilation products.At the elevation 1000 m,uncovering plastic film and hilling at rosette stage enhanced the photosynthetic function,in creased the assimilation products,and improved tobacco yield and quality.At elevation 1300 m,plastic film mulching in whole growth period caused the premature senescence,but maintained the photosynthetic function and assimilation products at a higher level.It was advocated that in the study area,plastic film mulching in whole growth period and uncovering plastic film and hilling at rosette stage would be appropriate for cultivating flue-cured tobacco at the elevations 1300m and 1000 m,respectively.     

小肠腺三色染色法

我们采用三色染色的方法对小肠肠腺细胞进行染色,杯状细胞、潘氏细胞、胞质和肠腺基膜呈现三种不同的颜色。细胞形态清晰,对比鲜艳,收到了理想效果。材料和方法1·材料人小肠为手术切除新鲜标本。10%甲醛固定24-48h,常规脱水,石蜡包埋。2·方法石蜡切片厚4-6μm,切片脱蜡,蒸馏水洗2m in,复合染液染3-5m in,70%乙醇分色,蒸馏水洗1m in,阿利新蓝染5m in,蒸馏水轻洗;0·2%光绿复染胞质、肠腺基膜20s;70%盐酸乙醇分色;梯度乙醇脱水;二甲苯透明;中性树胶封固。3·染液配制(1)复合染液:1%伊红(1g伊红,70%乙醇100m l)40m l,2%偶氮桃红(2g偶氮桃红甲…     

Seasonal changes in the ranging area of Brown-eared pheasant and its affecting factors in Huanglong Mountains, Shaanxi Province

A study on the seasonal changes in the ranging area of Brown-eared pheasant and its affecting factors was conducted in the Huanglongshan Nature Reserve, Huanglong County, Shaanxi Province, China, from March 2006 to January 2007. Forty used sites and forty random plots were selected along 8–9 transects crossing the study area. Fifteen factors related to the changes of altitude were measured in each site. The results showed that the altitude of home range of Brown-eared pheasant varied with seasons: the highest home range was found in summer, and the lowest one was found in winter, while the home range in autumn was higher than that in spring. According to the frequency of occurrences of Brown-eared pheasant in different seasons, we found that its home range occurred mainly at an altitude below 1400 m in spring, above 1500 m in summer, between 1200 m and 1500 m in autumn and below 1300 m in winter. The possible reason that Brown-eared pheasants preferred to live at lower altitude in spring was to have access to water sources and the abundance of food, correlated to the slope locations, number of trees and number of shrubs; in summer, they tended to appear at highest altitude, and the average height of shrubs, average height of grasses, sheltering class and distance to edge of woods, and human disturbance were affecting factors; in autumn, they appeared at higher altitude which was correlated with the covers of trees, shrubs and grasses, and ultimately related to the abundance of food; in winter, they lived at lowest altitude, which was correlated to the distance from the edge of woods, cover of trees and sheltering class, and ultimately related to the abundance of food and shelter.     

Seasonal changes in the ranging area of Brown-eared pheasant and its affecting factors in Huanglong Mountains, Shaanxi Province

A study on the seasonal changes in the ranging area of Brown-eared pheasant and its affecting factors was conducted in the Huanglongshan Nature Reserve, Huanglong County, Shaanxi Province, China, from March 2006 to January 2007. Forty used sites and forty random plots were selected along 8–9 transects crossing the study area. Fifteen factors related to the changes of altitude were measured in each site. The results showed that the altitude of home range of Brown-eared pheasant varied with seasons: the highest home range was found in summer, and the lowest one was found in winter, while the home range in autumn was higher than that in spring. According to the frequency of occurrences of Brown-eared pheasant in different seasons, we found that its home range occurred mainly at an altitude below 1400 m in spring, above 1500 m in summer, between 1200 m and 1500 m in autumn and below 1300 m in winter. The possible reason that Brown-eared pheasants preferred to live at lower altitude in spring was to have access to water sources and the abundance of food, correlated to the slope locations, number of trees and number of shrubs; in summer, they tended to appear at highest altitude, and the average height of shrubs, average height of grasses, sheltering class and distance to edge of woods, and human disturbance were affecting factors; in autumn, they appeared at higher altitude which was correlated with the covers of trees, shrubs and grasses, and ultimately related to the abundance of food; in winter, they lived at lowest altitude, which was correlated to the distance from the edge of woods, cover of trees and sheltering class, and ultimately related to the abundance of food and shelter.     

mTOR regulates TLR-induced c-fos and Th1 responses to HBV and HCV vaccines

Although IL-12 plays a critical role in priming Th1 and cytotoxic T lymphocyte(CTL) responses, Toll-like receptor(TLR) signaling only induces low amounts of IL-12 in dendritic cells and macrophages, implying the existence of stringent regulatory mechanisms. In this study, we sought to uncover the mechanisms underlying TLR-induced IL-12 expression and the Th1 response. By systemic screening, we identified a number of protein kinases involved in the regulation of TLRinduced IL-12 expression. In particular, PI3 K, ERK, and m TOR play critical roles in the TLR-induced Th1 response by regulating IL-12 and IL-10 production in innate immune cells. Moreover, we identified c-fos as a key molecule that mediates m TOR-regulated IL-12 and IL-10 expression in TLR signaling. Mechanistically, m TOR plays a crucial role in c-fos expression, thereby modulating NFκB binding to promoters of IL-12 and IL-10. By controlling the expression of a special innate gene program, m TOR can specifically regulate the TLR-induced T cell response in vivo. Furthermore, blockade of m TOR by rapamycin efficiently boosted TLR-induced antigen-specific T and B cell responses to HBV and HCV vaccines. Taken together, these results reveal a novel mechanism through which m TOR regulates TLR-induced IL-12 and IL-10 production, contributing new insights for strategies to improve vaccine efficacy.     

沙蛤中牛磺酸的制备研究

以沙蛤提取液中牛磺酸含量为指标,考察乙醇回流法、水煮法和预处理方法,并采用单因素和正交实验法优化工艺条件,确定了沙蛤中提取牛磺酸的最佳工艺。结果:提取牛磺酸的最佳工艺条件为:超声波破碎15 m in,60℃下80%乙醇回流40 m in,该条件下所得牛磺酸质量分数达6.41 mg.g-1原料。结论:超声波破碎与乙醇回流方法相结合,利于牛磺酸溶出,其含量提高26.9%。     

Synthesis and degradation of the major allergens in developing and germinating soybean seed

Gly m Bd 28K,Gly m Bd 30K and Gly m Bd 60K are the major soybean(Glycine max(L.)Merr.)allergens limiting the consumption of a good protein source for sensitive individuals.However,little is known about their temporal-spatial expression during seed development and upon germination.The present data shows that soy allergens accumulated in both the embryonic axes and cotyledon,but expression patterns differed depending on the specific allergen.Allergens accumulated sooner and to a greater level in cotyledons than in embryonic axes.Gly m Bd 28 began at 14 d after flowering,7 to 14 d earlier than Gly m Bd 30K and Gly m Bd 60K.Comparatively,their degradation was faster and more profound in embryonic axes than in cotyledons.Gly m Bd 60K began to decline at 36 h after imbibition and remained detectable up to 108 h in cotyledons.In contrast,the Glym Bd 60K protein was reduced at 24 h,and eventually disappeared at 96 h.In cotyledons Gly m Bd 28K first declined at 24 h,then increased from 36 h to 48 h,followed by its large reduction at 72 h after seed germination.These findings provide useful information on soy allergen biosynthesis and will help move forward towards developing a hypoallergenic soybean for safer food.     

Anatomical and morphological parameters of leaves and leaf petioles of Actinidia deliciosa

Differences in anatomy and morphology of the kiwifruit leaves and leaf petioles might play a considerable role in the sex-determination. Three months after bud break (June), the kiwifruit leaves of both male and female plants, grown on the vegetative and generative shoots showed different leaf area (128.6 ± 13.45 cm2 in male and 104.5 ± 4.02 cm2 in female plants) and shape. The most frequently leaf shape was determined as "folium cordatum" and "folium rotundato-cordatum". Higher values of total leaf thickness of the female leaves (190 ± 3.84 μm) in comparison to male leaves (174 ± 3.52 μm) were estimated, resulting in the thicker adaxial leaf epidermis and especially in thicker palisade parenchyma in female leaves (136 ± 2.76 μm in comparison to 104 ± 1.61 μm in male leaves). Typically bifacial leaves were observed in both male and female leaves. Anomocytic stomata in hypostomatic leaves were found. The reticulate venation appears to be the main type of leaf venation. Stalked stellate multicellular trichomes on the abaxial leaf side were frequently observed in the leaves of both sexes. No important differences between male and female plants were found in the structures of vascular system in leaves and leaf petioles. Thus leaf thickness and surface morphology of adaxial leaf epidermis can be considered as important structural parameters in the sex determination. This revised version was published online in July 2006 with corrections to the Cover Date.     

刺槐叶绿素荧光特性的研究

用L I-6400光合仪对黄土高原常用造林树木刺槐的叶绿素荧光动力学曲线、淬灭分析、荧光光曲线以及荧光AC I曲线等生理特性进行测定和对比分析.结果表明:随着光照时间的加大,刺槐的荧光参数ETR、qP和N PQ逐渐上升并在21 m in左右达到稳定,与光合同步.最大荧光产量F m在叶片转入黑暗后逐渐上升,在44 m in左右趋于稳定;N PQ则开始下降,在35 m in左右达到稳定.当光强度>200μm o l.m-2.s-1时,Ph iPS2和Ph iCO2呈线性正相关,而当光强度<200μm o l.m-2.-s 1时,Ph iPS2和Ph iCO2呈线性负相关.CO2浓度和刺槐的荧光光合速率、Ph iPS2、Ph iCO2值存在着一定的正相关关系.     

Vertical and seasonal distribution of flying beetles in a suburban temperate deciduous forest collected by water pan trap

Vertical and seasonal distributions of flying beetles were investigated in asuburban temperate deciduous forest in Kanazawa, Japan using water pan traps to determine the abundance and composition among vertical strata, change in the abundance and composition through seasons and determinant factors in generating the distributions. Traps were placed at three levels (0.5 m, 10 m, and 20 m above ground) on a tower. Samplings were carried out seasonally from May to November in 1999 and 2000. Variations in the abundance of flying beetles were observed from different layers. The results showed that the abundance and composition of flying beetles varied among strata and seasons. In both 1999 and 2000,Elateridae was consistently most abundant in the bottom layer, while Attelabidae and Cantharidae were most abundant in the upper layer. In 1999, Eucnemidae and overall scavengers were most abundance in the bottom layer, but results were not consistent with those in 2000. In general, the abundance of herbivores reaches a peak in the early season(May/June) and decreases in the following months. Peaks of abundance in predators vary vertically. In the bottom layer a peak was observed in the early season (May/June), while in the upper layer this was observed in July. Scavengers had two peaks, in May/June and September. These patterns indicated that vertical distributions in the abundance of differentfeeding guilds varied through seasons.     

Monoclonal neutralizing antibodies against EV71 screened from mice immunized with yeast-produced virus-like particles

Periodic outbreaks of hand, foot and mouth disease(HFMD) occur in children under 5 years old, and can cause death in some cases. The C4 strain of enterovirus 71(EV71) is the main pathogen that causes HFMD in China. Although no drugs against EV71 are available, some studies have shown that candidate vaccines or viral capsid proteins can produce anti-EV71 immunity. In this study, female BABL/c mice(6–8 weeks old) were immunized with virus-like particles(VLPs) of EV71 produced in yeast to screen for anti-EV71 antibodies. Two hybridomas that could produce neutralizing antibodies against EV71 were obtained. Both neutralizing m Abs(D4 and G12) were confirmed to bind the VP1 capsid protein of EV71, and could protect 95% cells from 100 TCID50 EV71 infection at 25 μg/m L solution(lowest concentration). Those two neutralizing m Abs identified in the study may be promising candidates in development for m Abs to treat EV71 infection, and utilized as suitable reagents for use in diagnostic tests and biological studies.