Karyotype analyses in three Patagonian and S. Andean endemic genera ofNicotianeae (Solanaceae)

The somatic chromosomes and karyotypes of threeNicotianeae have been studied for the first time. All of them have 2n = 2x = 22 and symmetrical karyotypes.Benthamiella pycnophylloides has 9 m pairs + 1 sm pair + 1 st pair; pairs 2, 4, 5, and 11 bear microsatellites.Combera paradoxa andPantacantha ameghinoi have 9 m pairs + 2 sm pairs; pair 11 ofC. paradoxa is satellited, while pair 9 ofP. ameghinoi bears microsatellites and shows a pericentric inversion in heterozygous state in 20% of the seedlings. Results are compared with previous chromosome reports for the tribe. The cytological data support their present position in the family system. Besides,Benthamiella, Combera andPantacantha appear to be primitive genera ofNicotianeae, a comparatively advanced tribe within the family.Chromosome studies onNicotianeae (Solanaceae) 1.     

Functional significance of amylase polymorphism in Drosophila melanogaster. III. Ontogeny of amylase and some α-glucosidases

Changes in amylase (E.C. 3.2.1.1), maltase (E.C. 3.2.1.20), sucrase, and PNPGase activities in relation to changes in wet weight and protein content were studied during the development of larvae and adult flies from two strains of Drosophila melanogaster, homozygous for different amylase alleles. All -glucosidase activities increase exponentially during a large part of larval development, parallel to the increase in weight, and drop at the end of the third instar. Amylase activity of the Amy ¹ strain follows the same pattern. In contrast, amylase activity of the Amy ^4,6 strain continues its exponential increase longer. In the third larval instar amylase activity in the Amy ^4,6 strain becomes much higher than in the Amy ¹ strain. During the first hours of adult life amylase activity of the two strains does not differ. Then Amy ^4,6 activity starts to rise and becomes much higher (4–5 times) than Amy ¹ amylase activity, which remains approximately constant. All adult enzyme activities are much higher than in larvae. Comparison of enzyme activity of amylase and -glucosidases in larvae and adults confirms that differences in amylase activities can become important only when starch is a limiting factor in the food.The investigations were supported by the Foundation for Fundamental Biological Research (BION), which is subsidized by the Netherlands Organization for the Advancement of Pure Research (Z.W.O.).     

Leucocyanidin: Synthesis and properties of (2R,3S,4R)-(+)-3,4,5,7,3′,4′-hexahydroxyflavan

An isomer of leucocyanidin, (2R,3S,4R)-(+)-3,4,5,7,3′,4′-hexahydroxyflavan has been synthesized from (+)-taxifolin, isolated in its phe     

The phytochemistry of proanthocyanidin polymers

The structures of 38 proanthocyanidin polymers (condensed tannins) from 14 widely distributed families of plants are described. The polymers have been isolated from a wide variety of tissues including fruit (ripe and unripe), leaves, bark and phloem. They are all based on a common 4-8 (or 6) linked polyflavan-3-ol structure, analogous to B-type proanthocyanidin dimers.     

Triage of women with equivocal or low-grade cervical cytology results: a meta-analysis of the HPV test positivity rate

Consistent evidence underlines the utility of human papillomavirus (HPV) DNA testing in the management of women with equivocal cervical cytological abnormalities, but not in case of low-grade lesions. We performed a meta-analysis including studies where the high-risk probe of the Hybrid Capture-II is used to triage these two cytological categories. The triage test-positivity rate reflects the colposcopy referral workload.Data were pooled on the HPV test positivity rate in women with atypical squamous cells of undetermined significance (ASCUS/ASC-US) or low-grade squamous intraepithelial lesions (LSIL), derived from different cytological classification systems. The meta-analysis was restricted to studies, published between 1991 and 2007. A random-effect model was applied for meta-analytical pooling and the influence of covariates on the HPV positivity rate was analyzed by meta-regression. The variation by age was assessed within individual studies since age strata were not defined uniformly. On an average, 43% (95% CI: 40–46%) of women with ASCUS/ASC-US were high-risk HPV positive (range 23–74%). In women with LSIL, the pooled positivity rate was 76% (95% CI: 71–81%; range 55–89%). In spite of considerable inter-study heterogeneity, the difference in HPV positivity between the two triage groups was large and highly significant: 32% (95% CI: 27–38%). HPV rates dropped tremendously as age and cutoffs of test positivity increased. Other factors (cytological classification system, country, continent, collection method and year of publication) had no statistically significant impact, except in LSIL triage where HPV positivity was significantly lower in European compared to American studies. Women with LSIL, especially younger women, have high HPV positivity rates suggesting limited utility of reflex HPV triaging these cases. Research is needed to identify more specific methods to triage women with low-grade squamous cervical lesions.     

The retina of Psammodynastes pulverulentus (Boie, 1827) and Telescopus fallax (Fleischmann, 1831) with a discussion of their phylogenetic significance (Colubroidea, Serpentes)

The retinas of the rear-faned snakes Psammodynastes pulverulentus and Telescopus fallax have been examined. P.pulverulentus has a simplex retina in which the proportion between the numbers of outer and inner nuclear layers is 1:8 which means that P.pulverulentus has a typical diurnal retina. This is further stressed by the find of a shallow, temporal fovea until now only known from a single snake genus, Ahaetulla. T. fallax has a two-tier retina with double cones, with almost the same numbers of outer and inner nuclear layers (1:1.3) which means that T.fallax has a typical nocturnal retina. - The two species are usually regarded as belonging to the boigine (s. str.) snakes, but the presence of double cones in both species and not least the presence of a retinal fovea in Psammodynastes, makes this assignment dubious, and their probable relationships to other Colubroids are discussed.     

Conservation of Functionally Important Global Motions in an Enzyme Superfamily across Varying Quaternary Structures

The α‐d‐phosphohexomutase superfamily comprises enzymes involved in carbohydrate metabolism that are found in all kingdoms of life. Recent biophysical studies have shown for the first time that several of these enzymes exist as dimers in solution, prompting an examination of the oligomeric state of all proteins of known structure in the superfamily (11 different proteins; 31 crystal structures) via computational and experimental analyses. We find that these proteins range in quaternary structure from monomers to tetramers, with 6 of the 11 known structures being likely oligomers. The oligomeric state of these proteins not only is associated in some cases with enzyme subgroup (i.e., substrate specificity) but also appears to depend on domain of life, with the two archaeal proteins existing as higher‐order oligomers. Within the oligomers, three distinct interfaces are observed, one of which is found in both archaeal and bacterial proteins. Normal mode analysis shows that the topological arrangement of the oligomers permits domain 4 of each protomer to move independently as required for catalysis. Our analysis suggests that the advantages associated with protein flexibility in this enzyme family are of sufficient importance to be maintained during the evolution of multiple independent oligomers. This study is one of the first showing that global motions may be conserved not only within protein families but also across members of a superfamily with varying oligomeric structures.     

微RNA在卵巢上皮性癌发生发展中作用及其临床意义

研究表明,miRNA参与了胚胎发育、损伤修复、糖尿病、心脏病等许多重要生理病理过程,特别是在恶性肿瘤的发生发展中发挥了重要作用,并具有潜在的临床意义。本文比较详细地叙述了有关miRNA的重要基础研究成果,并就miRNA在卵巢癌组织及细胞中的表达、miRNA在卵巢癌发生发展中的作用、miRNA与卵巢癌早期诊断、化疗耐药及预后判断等方面的最新研究成果进行了综述。     

泌尿生殖道分泌物支原体培养临床分析

探讨泌尿生殖道分泌物支原体培养的临床意义.取泌尿生殖道感染的男性尿拭子和女性宫颈分泌物1 095份进行支原体培养和药敏试验,根据药敏结果进行治疗及疗效观察.1095例患者中支原体阳性365例(33.3％),其中解脲脲原体(Ureaplasma urealyticum,Uu)感染287例,人型支原体(Mycoplasma hominis,Mh)感染55例,Uu与Mh混合感染23例.药敏试验结果显示对强力霉素、米诺环素敏感率分别为90.4％和88.8％.对林可霉素、诺氟沙星、氧氟沙星的耐药率分别为86.8％、82.5％、81.1％.男性患者根据药敏结果分别进行强力霉素和米诺环素单药治疗,其治愈率为79.5％、76.9％,女性患者联合干扰素栓剂治疗,治愈率达83.6％和82.2％.鉴于泌尿生殖道分泌物支原体的高感染率以及并不理想的临床治愈率,广泛应用分泌物支原体培养法值得商榷.