Microsatellite primers in the Chinese dove tree, Davidia involucrata (Cornaceae), a relic species of the Tertiary

? Premise of the study: The first microsatellite primers were developed for Davidia involucrata, an endangered relic species of the Tertiary in China, to further describe its genetic variability and population structure. ? Methods and Results: Using the Fast Isolation by AFLP of Sequences Containing Repeats (FIASCO) protocol, 15 polymorphic microsatellite loci were isolated and characterized in 20 individuals from the germplasm collections of D. involucrata at the Hunan Forest Botanical Garden. High levels of polymorphism were revealed, with the total number of alleles per locus and the number of alleles per locus per individual ranging from two to 13 and from one to six, respectively. ? Conclusions: The multibanded patterns of microsatellite loci obtained in the current study confirmed that D. involucrata might be a polyploid species. The primers will be useful for studies of genetic diversity and for guiding conservation strategies for D. involucrata.     

Phytochemical investigation on the fruits of Camptotheca acuminata and their chemotaxonomic significance

A phytochemical investigation on the fruits of Camptotheca acuminata led to the isolation of 13 compounds, including five coumarins (1–5), two alkaloids (6 and 7), two triterpenoids (8 and 9), three lactones (10–12) and a sesquiterpene (13). The structures of these compounds were elucidated by extensive spectroscopic methods and comparion with literature data. All compounds were isolated from the Nyssaceae family for the first time. Additionally, it should be noted that this is the first report of coumarins in the C. acuminata. The chemotaxonomic significance of the isolated compounds was summarised.     

Proteic toxin-antitoxin, bacterial plasmid addiction systems and their evolution with special reference to the pas system of pTF-FC2

Genes encoding toxin-antitoxin proteins are frequently found on plasmids where they serve to stabilize the plasmid within a bacterial population. The toxin-antitoxin proteins do not increase the likelihood of a progeny cell receiving a plasmid but rather function as post-segregational killing mechanisms which decrease the proportion of cells that survive after losing the plasmid. These toxin-antitoxin couples therefore act as plasmid addiction systems. Several new proteic toxin-antitoxin systems have been identified and these systems appear to be ubiquitous on the chromosomes of bacteria and archaea. When placed on plasmids, these chromosomal systems also have the ability to stabilize plasmids and in at least one case, chromosomal- and plasmid-based toxin-antitoxin systems have been shown to interact. Recent findings regarding toxin-antitoxin systems and questions that have arisen as a result of these findings are reviewed.     

不同色彩珙桐苞片与叶片的生理特性研究

以生长在同一生境下的粉红珙桐和普通珙桐植株为试材,比较两种珙桐苞片/叶片的色素、基础代谢物含量和酶活性,探讨粉红珙桐苞片与叶片的呈色机理。结果显示：粉红珙桐叶片的类黄酮含量是普通珙桐的1.52倍,两种珙桐苞片中的类黄酮含量都较低,且无显著差异（P>0.05）;粉红珙桐苞片和叶片的花色苷含量极显著高于普通珙桐（P<0.01）,分别是普通珙桐的1.68倍和3.67倍;粉红叶片的光合色素略低于绿色叶片,但无显著差异（P>0.05）。粉红珙桐苞片和叶片的可溶性糖、脯氨酸含量显著高于普通珙桐（P<0.05）,可溶性蛋白含量则相反;苞片的可溶性糖含量极显著低于叶片（P<0.01）,而可溶性蛋白和脯氨酸含量更高（P<0.01）。粉红珙桐苞片和叶片的苯丙氨酸解氨酶（PAL）、查尔酮异构酶（CHI）活性极显著高于普通珙桐（P<0.01）,过氧化物酶（POD）和超氧化物歧化酶（SOD）活性无显著差异（P>0.05）;苞片中的酶活性大多都显著高于叶片（P<0.05）,尤其是CHI活性。类黄酮、花色苷含量与可溶性糖、脯氨酸含量、PAL、CHI活性呈显著正相关,而与可溶性蛋白含量显著负相关。研究表明,花色苷是珙桐苞片转粉红的直接因素,而叶片转粉红受类黄酮和花色苷的共同影响,可溶性糖、可溶性蛋白、脯氨酸、PAL、CHI影响花色苷的合成。     

Pollen walls of Araceae,with special reference to their fossilization potential

The pollen grains, the pistil, growth of the pollen tube and its pathway are described in Borago officinalis and Heliotropium europaeum. The exine is thick in both taxa but it is covered with dense gemmae in Borago. The intine seems to be thicker and contains more proteins in Borago than in Heliotropium. Starch is very abundant in the latter while it is lacking in the former. The style is hollow in Borago with a stylar canal running from the stigma to the ovary, while in Heliotropium it is broadly cone‐shaped with papillae located at the base of the cone (the “stigmatic ring") and not at the top of the style as usual. In Borago stigmatic papillae are unicellular, skittle‐shaped and have a thick pectocellulosic wall and an equally thick cuticular layer, while in Heliotropium the stigmatic papillae are unicellular, elongated cone‐shaped with a thin pecto‐cellulosic wall and have an apparently reduced cuticular layer. The stigmatic exudate is very abundant on the stigmas of Heliotropium even before anthesis while it is absent on those of Borago except when allo‐pollination occurs. Pollen tube growth has been followed from stigma to ovules in both taxa.     

国产6种点地梅属植物的核型及其系统学意义

报道了点地梅属6种12个居群的染色体数目和核型。它们的染色体数目(2n)、核型公式(KF)、染色体相对长度组成(CRL)、核型不对称性系数(A．sK%)和核型类型(KT)分别为：点地梅在南京的2个居群都是2n=2x=20,KF=18m 2sm,CRL=2L 6M2 10M1 2S,核型KT属于1A型,但核型不对称性系数As．K%分别是55.04％和56．71％;北点地梅在内蒙古锡林郭勒和白音锡勒居群的2n=2x=20,KF分别为16m 2sm 2st 1b和16m 2sm 2st 4b,染色体相对长度组成分别是14M2 4M1 2S 1b和12M2 6M1 2S 4b,核型不对称性系数As．K％分别是57．65％和58．86％,属2A型和2B型;高原点地梅在青海玛沁县昌马河居群和兴海县温泉居群都是2n=2x=20,KF=10m 8sm 2st。但相对长度组成分别为12M2 8M1和4L 6M2 6M1 4S,As．K％分别是60．35％和62．57％,属2A型和2B型;雅江点地梅在青海玛多县巴颜喀拉山居群和大通县达坂山居群分别为2n=4x=40和2n=6x=60,KF=36m 2sm 2st和KF=46m 10sm 4st 2b,CRL=2L 20M2 14M1 4S和CRL=6L 30M2 16M1 8S 2b,As．K％分别为55．62％和58．31％,核型均属于2B;巴颜喀拉山北坡的鳞叶点地梅2n=40、60、80。西藏点地梅青海湖居群中有2种细胞型：①2n=2x=24,KF=12m 6sm 6st 4b,CRL=6L 6M2 8M1 4S 4b,As．K％=65．74％,核型属2B;②2n=2x=22,KF=14m 4sm(2SAT) 4st,CRL=4L 6M2 8M1(2sAT) 4S,As．K％=63．40％,核型也属于2B。西宁西山湾居群也有2种细胞型：①2n=3x=36,KF=36m,CRL=4L 12M2 20M1,As．K％=54．82％,核型属1A;②2n=3x=33,KF=33m,CRL=3L 12M2 18M1,As．K％=52．11％,核型属1A。点地梅属的染色体原始基数可能是x=10,在种间或种内观察到有3种核型变化：染色体非整倍性变化、多倍化和核型不对称性变化。将2倍体居群的核型和不对称性进行比较,可以看出点地梅是较对称的核型。因此,在研究的种中应是比较原始的类群。北点地梅的核型不对称性和进化程度高于点地梅而低于高原点地梅和西藏点地梅。染色体多倍化的雅江点地梅、鳞叶点地梅和西藏点地梅等在核型上也许是最进化的类群。     

The cephalic arterial system in carnivores, with special reference to the systematic classification

The cephalic arterial pattern in 53 fissipeds, representing all the classical families, is described on the basis of corrosion casts prepared by means of a special plastic injection and corrosion technique. The results are discussed on an ontogenetic and phylogenetic basis and related to current theories on the systematic classification of fissipeds at a higher taxonomic level (infraorders or superfamilies). In this respect, especially the systematic position of the canids and hyaenids in relation to the felids is discussed, the greatest importance being attached to the contribution of the external carotid artery system to the intracranial circulation. Also the very specific cephalic arterial pattern in the herpestines, one of the two viverrid subfamilies studied, is emphasized.     

大相岭自然保护区珙桐群落植物区系、结构及动态

在多次调查的基础上,对四川大相岭自然保护区珙桐(Davidia involucrata)群落的植物区系组成、群落结构、更新现状以及群落演替进行了探究。结果表明:(1)大相岭自然保护区的植被为亚热带向温带过渡的区系类型,大量古老孑遗属的存在反映出珙桐群落植物区系的孑遗性和古老性。(2)群落整体径级结构呈偏正态分布型,高度级结构呈倒J型,群落结构发展趋势较为稳定。(3)大相岭自然保护区珙桐种群整体年龄结构近似呈金字塔型,为增长型种群。总体来说,珙桐纯林(C类型群落)搭配优势度最优,处于后期稳定型演替阶段,是大相岭自然保护区珙桐群落中的顶极群落。研究认为,设立专门的珙桐保护区开展就地保护是针对此类珙桐原生群落有效的保护方法。     

Pancreatic APUD cells in older chick embryos,with special reference to their identity

Summary Pancreatic APUD cells showing formaldehyde-induced fluorescence in Black Australorp chick embryos of nine to eighteen days of incubation, proved, on subsequent staining and silver impregnation, to be A, B, D and, from sixteen days, enterochromaffin (EC) cells. EC and D cells were scattered in the exocrine parenchyma, the latter cells increasing with time. Some groups of B cells were associated with large A islets from the ninth day of incubation onwards. The composition of A islets (A and some D cells) and B islets (B and some D cells) and the distribution attained (A islets in the splenic and third lobes; B islets in all lobes), accords with the situation reported for adults.     

Spermatozoa of the Anomalodesmata (Bivalvia, Mollusca) with special reference to relationships within the group

Sperm ultrastructure in the marine bivalve order Anomalodesmata is considered in the light of new information for Australian Myochama anomioides and Cuspidaria latesulcata . In M. anomioides , the acrosomal complex lies posterior to the nucleus, in contact with the asymmetrical midpiece mitochondria – an unusual configuration reported from most of the studied Anomalodesmata. Spermatozoa of M. anomioides resemble those of Myadora brevis (both in family Myochamidae). Myochamid spermatozoa are considerably less modified than those of the Lyonsiidae or Laternulidae, and may prove a basal type within the non-septibranch anomalodesmatans. In contrast, C. latesulcata differs from other examined anomalodesmatans in having an anterior acrosomal complex and radial midpiece mitochondria (classic aquasperm features). Sperm data for the Anomalodesmata are limited but congruent with the most recent phylogenetic analyses that recognize distinct 'thraciid' and 'lyonsiid' clades. Results for C. latesulcata suggest septibranch origins before the development of a posteriorly positioned acrosomal complex and mitochondrial asymmetry.     

喜树幼苗中喜树碱和10-羟基喜树碱对热激的响应特点和意义

植物在长期的生态环境适应过程中,产生了包括生物碱在内的大量次生代谢物。本文以我国特有树种——喜树(Camptotheca acuminata Decaisne)为材料,研究其不同器官中喜树碱(camptothecin,CPT)和10-羟基喜树碱(10-hydroxycamptothecin,HCPT)在不同热激温度和时间情况下的含量变化。CPT和HCPT变化呈现出较好的相互消长关系,并且分别在38℃和40℃达到各自的峰值,比以丙二醛和叶绿素为指标的致死温度低了2-4℃：HCPT在热激过程中的变化较CPT活跃;极易受到攻击和伤害的嫩叶中的生物碱含量变化最大。由此推断,CPT和HCPT遵循“幼嫩和生殖器官优先保护”的原则,从而有效地缓解了高温胁迫,并且HCPT和CPT代表了不同的防御策略。     

The occurrence of vertical resin canals in Keteleeria, with reference to its systematic position in Pinaceae

The variation in the number of resin canals in the secondary xylem of Keteleeria fortunei (A. Murray bis) Carrière is determined. At all levels from base to top of a tree, resin canals are absent rearer the pith, but they (sporadically) appear after a certain cambial age. In addition, the occurrence of resin canals in seven named species of Keteleeria was surveyed. It was confirmed that normal vertical resin canals do occur in the mature parts of secondary xylem, but that they may be absent in the juvenile parts of secondary xylem of stems, as well as in branches and in seedlings or saplings. Earlier investigations reporting the absence of resin canals altogether in this genus may have been misled by the use of younger (immature) specimens instead of mature stems of trees. The distribution pattern of resin canals found in Keteleeria is systematically significant because it supports a new system of classification of Pinaceae, in which Keteleeria is believed to have a close relationship with Nothotsuga.     

喜树幼苗中喜树碱和10-羟基喜树碱对热激的响应特点和意义

植物在长期的生态环境适应过程中,产生了包括生物碱在内的大量次生代谢物.本文以我国特有树种--喜树(Camptotheca acuminata Decaisne)为材料,研究其不同器官中喜树碱(camptothecin,CPT)和10-羟基喜树碱(10-hydroxycamptothecin,HCPT)在不同热激温度和时间情况下的含量变化.CPT和HCPT变化呈现出较好的相互消长关系,并且分别在38℃和40℃达到各自的峰值,比以丙二醛和叶绿素为指标的致死温度低了2~4℃;HCPT在热激过程中的变化较CPT活跃;极易受到攻击和伤害的嫩叶中的生物碱含量变化最大.由此推断,CPT和HCPT遵循"幼嫩和生殖器官优先保护"的原则,从而有效地缓解了高温胁迫,并且HCPT和CPT代表了不同的防御策略.     

Cytogenetics of the Anopheles gambiae complex in Sudan, with special reference to An. arabiensis: relationships with East and West African populations

The species composition of malaria vector mosquitoes belonging to the Anopheles gambiae complex (Diptera: Culicidae) from >40 localities in Sudan, representing most ecological situations, was determined by analysis of ovarian polytene chromosomes. Of 2162 females, 93% were identified as An. arabiensis Patton and 7% were An. gambiae Giles sensu stricto. No hybrids were found between the two species. Anopheles arabiensis occurred in all but two sites, whereas An. gambiae s.s. was effectively limited to the southernmost, more humid localities. For chromosomal paracentric inversions, the degree of polymorphism was low in An. gambiae s.s. (inversions 2La, 2Rb and 2Rd), higher in An. arabiensis (inversions Xe, 2Ra, b, bc, d1, s; 3Ra, d). Anopheles gambiae samples from Sudan were all apparently panmictic, i.e. they did not show restricted gene flow such as observed among West African populations (interpreted as incipient speciation). Chromosomal inversion patterns of An. gambiae in southern Sudan showed characteristics of intergrading Savanna/Forest populations similar to those observed in comparable eco-climatic situations of West Africa. Anopheles arabiensis was polymorphic for inversion systems recorded in West Africa (2Ra, 2Rb, 2Rdl, 3Ra) and for a novel 2Rs polymorphism, overlapping with inversion systems 2Rb and 2Rd1. Samples carrying the 2Rs inversion were mostly from Khashm-el-Girba area in central-eastern Sudan. In the great majority of the samples all polymorphic inversions were found to be in Hardy-Weinberg equilibrium. Sudan populations of An. arabiensis should therefore be considered as generally panmictic. Anopheles arabiensis shows more inversion polymorphism in west than in east African populations. Sudan populations have more evident similarities with those from westwards than those from eastwards of the Great Rift Valley. The possible influence of the Rift on evolution of An. arabiensis is discussed.