The protective shell: sclereids and their mechanical function in corollas of some species of Camellia (Theaceae)

Studies of rain-wash effects on pollen have shown that flower structures can protect susceptible pollen from rain. It remains unclear, however, how a thin corolla can withstand external force and perform its protective function. The sclereids in petals of several species of Camellia (Theaceae) were anatomically investigated to determine their mechanical properties. To examine the effects of changing physical environment on the occurrence of sclereids in petals, sclereid density in petals of six species, including wild samples from different rainfall zones and samples from a greenhouse under mild conditions without wind and rain, were examined and statistically analysed. The results showed that the occurrence of sclereids in petals varied with physical environment. The number of sclereids in the same species increased with the increasing rainfall. There were abundant sclereids in petals of the wild species, but few or no sclereids in species cultivated in the greenhouse. Moreover, the anatomical features of sclereids, especially the unique distribution pattern that has not hitherto been described, were correlated with external environmental pressures. Our observations reveal a novel mechanical system in the corolla and provide further evidence for the hypothesis that flower structures may protect rain-susceptible pollen.     

茶树CsGME1基因的克隆与逆境胁迫响应分析

该研究基于茶树转录组和基因组信息,以茶树‘龙井43’为实验材料,从其cDNA中克隆获得茶树CsGME1基因,并对其蛋白序列特征、基因表达模式及其在不同非生物胁迫下的表达水平进行实时荧光定量分析。结果显示:(1)茶树CsGME1开放阅读框长度为1131 bp,编码376个氨基酸;该序列与多个相关物种的GME氨基酸序列一致性为94.25%,均含有NAD结合域。(2)进化树分析表明,茶树CsGME1基因与番茄SlGME1亲缘关系较近,与水稻OsGME2亲缘关系最远。(3)CsGME1蛋白属于亲水性蛋白,理论相对分子量为42046.84 Da,理论等电点为5.73,具有4个无序化区域,无序化程度较低;CsGME1蛋白二级结构由39.25%α-螺旋,13.26%延伸主链,5.84%β-转角和41.38%随机卷曲组成;三级结构分析结果显示,CsGME1包含螺旋和随机卷曲,与二级结构吻合。(4)荧光定量分析结果显示,在高温(38℃)、低温(4℃)、干旱(20%PEG)和高盐(200 mmol·L-1 NaCl)4种非生物胁迫处理下,茶树CsGME1基因均有响应,且表达存在差异,推测CsGME1参与了茶树的逆境胁迫响应过程。     

N-Acylation of N-Desulfated Heparin

We found that the epigallocatechin gallate (EGCG)/epigallocatechin (EGC) ratio in a green tea (Camellia sinensis L.) extract was affected by the extraction temperature. The EGCG/EGC ratio in the 4 °C extract was around 1:3-4, whereas in the 100 °C extract, it was around 1:0.7. Oral administration of the mixture with a high EGC ratio (1:2-3 = EGCG/EGC) resulted in greater IgA production by murine Peyer’s patch cells.     

Volatile Compounds Formed on Roasting dl-α-Alanine with d-Glucose

The mixture of dl-α-alanine and d-glucose was roasted at 250° for about an hour in nitrogen atmosphere. From the volatile condensates were isolated and identified alkyl and acyl pyrroles, alkyl pyrrole-2-aldehydes, furfuryl pyrroles, alkyl pyrazines and furanic compounds. The identification of these compounds was based on the spectroscopic methods (MS, GC-MS and IR) and gas chromatographic analysis.     

油茶芽苗砧嫁接口愈合过程解剖学研究

采用石蜡切片法对油茶（Camellia oleifera）芽苗砧嫁接口的愈合过程进行组织解剖学研究。观察结果表明：（1）在嫁接后的第4天,嫁接口产生隔离层;在嫁接后的第8天,嫁接口的砧木产生愈伤组织;在嫁接后的第16天,嫁接口的接穗产生愈伤组织;在嫁接后的第22天,嫁接口的砧木与接穗连接;在嫁接后的第29天,嫁接口的形成层分化形成;在嫁接后的第35天,嫁接口的愈伤组织维管束形成,接穗连接成功。（2）油茶芽苗砧嫁接部位愈伤组织形成前,芽苗砧木的解剖结构在短时间内加速发育,逐渐与接穗的组织结构相似。（3）嫁接口的形成层和其它薄壁细胞组织均能产生愈伤组织,但形成层是其主要来源。     

Effects of the aqueous extract of white tea (Camellia sinensis) in a streptozotocin-induced diabetes model of rats

White tea (WT) is very similar to green tea (GT) but it is exceptionally prepared only from the buds and young tea leaves of Camelia sinensis plant while GT is prepared from the matured tea leaves. The present study was investigated to examine the effects of a 0.5% aqueous extract of WT in a streptozotocin-induced diabetes model of rats. Six-week-old male Sprague-Dawley rats were divided into 3 groups of 6 animals in each group namely: normal control (NC), diabetic control (DBC) and diabetic white tea (DWT). Diabetes was induced by an intraperitoneal injection of streptozotocin (65 mg/kg BW) in DBC and DWT groups except the NC group. After 4 weeks feeding of 0.5% aqueous extracts of WT, the drink intake was significantly (P < 0.05) increased in the DWT group compared to the DBC and NC groups. Blood glucose concentrations were significantly decreased and glucose tolerance ability was significantly improved in the DWT group compared to the DBC group. Liver weight and liver glycogen were significantly increased and serum total cholesterol and LDL-cholesterol were significantly decreased in the DWT group compared to the DBC group. The food intake, body weight gain, serum insulin and fructosamine concentrations were not influenced by the consumption of WT. Data of this study suggest that the 0.5% aqueous extract of WT is effective to reduce most of the diabetes associated abnormalities in a steptozotocin-induced diabetes model of rats.     

Oxidative coupling of the pyrogallol B-ring with a galloyl group during enzymatic oxidation of epigallocatechin 3-O-gallate

In order to clarify the mechanism for formation of catechin oligomers during the fermentation stage of black tea manufacture, epigallocatechin-3-O-gallate, the most abundant tea flavanol in fresh tea leaves, was enzymatically oxidized and the resulting unstable quinone metabolites were converted to phenazine derivatives by treatment with o-phenylenediamine. In addition to formation of monomeric and dimeric derivatives, four trimeric derivatives were isolated whose structures were determined by application of spectroscopic methods. The derivatives differed from each other in the location of the phenazine moieties and in the atropisomerism of the biphenyl bond. The results suggested that oxidative coupling of the galloyl group with the B-ring proceeds by a quinone dimerization mechanism similar to that for production of theasinensins.     

陕西南部地区茶叶挥发性成分的研究

用水蒸气蒸馏法分别从陕西南部不同产地的茶叶中提取挥发油,利用气相色谱-质谱联用技术对挥发油中的化学成分进行分离和结构鉴定,运用气相色谱面积归一化法确定各个成分的相对百分含量。从南郑县茶叶挥发油中鉴出51种成分,从宁强县茶叶挥发油中鉴出47种成分,从西乡县茶叶挥发油中鉴出46种成分,各挥发油成分存在着一定的差异。对陕南不同产地茶叶的挥发油做了抗氧化试验,结果表明各挥发油对.OH均有明显的清除作用。     

山茶CjMYB1基因的克隆及表达分析

该研究通过序列比对分析,以野生红山茶和不同花色品种山茶为材料,采用PCR方法克隆CjMYB1基因,并通过生物信息学和表达分析对其进行初步研究,为深入研究山茶CjMYB1基因在花色形成和花发育过程的调控机理奠定理论基础。结果表明：(1)成功克隆获得山茶CjMYB1基因(GenBank登录号为OL347930),其开放阅读框长为879 bp,编码292个氨基酸,相对分子质量为33.17 kD;CjMYB1基因属于R2R3-MYB转录因子,且与拟南芥MYB基因家族的第7亚组处于同一分支。(2)荧光定量PCR分析发现,山茶CjMYB1基因在野生红山茶花芽中表达量最高,在萼片、花瓣、雄蕊和心皮中都有较高的表达量,推测其在山茶花器官发育中发挥着重要作用;在红色山茶品种中表达量较高,而在粉色、淡黄色、白色山茶品种中表达量较低,说明CjMYB1基因可能在红色山茶品种的花色苷合成途径中起到了关键作用。(3)亚细胞定位实验表明,CjMYB1蛋白定位在细胞核。