Three new genera of the Asteraceae-Gnaphalieae from the Gape Region

Three new monotypic genera from the Cape Floral Region of South Africa are described. Calotesta Karis, a genus closely related to Metalasia and Alrichantha gemmifera (Karis, 1989) is characterized by its persistent, thick and strongly cutinized testa epidermis. The more distantly related Hydwidea has rather large, solitary white capitula and very thick-walled apical pappus cells. Planea Karis is a new genus established for Metalasia schlechteri L. Bol., a species which must be removed from Metalasia (Karis, 1989). Planea has strongly carinate leaves with involute but characteristically flat margins and narrowly ovate apical anther appendage with a peculiar marginal pattern. Discussions concerning morphology and systematic position as well as illustrations and distribution maps of all taxa are provided.     

几种念珠菌DNA总含量的流式细胞分析

应用流式细胞术(FCM)对处于稳定生长阶段的念珠菌属(Candida)的7种8株念珠菌进行了DNA总含量的流式细胞(FCM)分析。这8株念珠菌是:白念珠菌(C.albicans)2株,热带念珠菌(C.tropicalis),克柔念珠菌(C.krusei),近平滑念珠菌(C.parapsiolosis),乳酒念珠菌(C.kefyr),白念珠菌星形变种(C.stellatoidea),即血清B型白念珠菌,季也蒙念珠菌(C.guilliermondii)各一株。应用EB一步插入法染色,用鸡红细胞(CRBC)作为内参标准进行DNA总含量测定。分析结果表明:稳定生长阶段的组方图上,大多数念珠菌细胞处于DNA合成周期的G_0/G_1期;DNA总含量有明显的种间和种内差异。     

Genetic tagging: contemporary molecular ecology

Population genetic analyses have been highly successful in deciphering inter- and intra-specific evolutionary relationships, levels of gene flow, genetic divergence and effective population sizes. Parameters estimated by traditional population genetic analyses are evolutionary averages and thus not necessarily relevant for contemporary ecological or conservation issues. Molecular data can, however, also provide insight into contemporary patterns of divergence, population size and gene flow when a sufficient number of variable loci are analysed to focus subsequent data analyses on individuals rather than populations. Genetic tagging of individuals is an example of such individual-based approaches and recent studies have shown it to be a viable alternative to traditional tagging methods. Owing to the ubiquitous presence of hyper-variable DNA sequences in eukaryote genomes it is in principle possible to tag any eukaryote species and the required DNA can be obtained indirectly from substrates such as faeces, sloughed skin and hair. The purpose of this paper is to present the concept of genetic tagging and to further advocate the extension of individual-based genetic analyses beyond the identification of individuals to other kinds of relationships, such as parent-offspring relations, which more fully exploit the genetic nature of the data.     

Polymorphism hides cryptic species in Oerstedia dorsalis (Nemertea, Hoplonemertea)

The marine hoplonemertean Oerstedia dorsalis is considered to be a highly polymorphic species with extensive geographic distribution. We show, based on mitochondrial cytochrome c oxidase subunit I, 16S and nuclear internal transcribed spacer sequences, that there are genetic subsets withing this species. Seventy-one specimens of various colours from different geographic localities (in Europe) were sequenced and analysed using statistical parsimony and Bayesian analysis. Both analyses supported nine major clades. We conclude that O. dorsalis hides different species with geographic resolution. These species, however, appear to be polymorphic as well, and we find no diagnostic features in pigmentation or external characters to separate species within this complex.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 556–567.     

Multiphasic Uptake in Plants II. Mineral Cations, Chloride, and Boric Acid

Uptake of alkali cations, metal ions, chloride, and boric acid is shown by reanalysis of available data to be mediated by single, multiphasic mechanisms which may be fundamentally similar in a variety of plants and tissues.     

Effect of calcium on sulfate uptake by barley roots

Abstract Sulfate uptake by excised roots of barley (Hordeum vulgare L.) was maximal in the presence of about 3x10^-3M CaCl₂. Kinetic studies contraindicate a stoichiometric binding of calcium to the carrier for sulfate, in contrast to findings of Cuppoletti and Segel (Biochemistry 14: 471–4718, 1975) for the filamentous fungus Penicillium notatum. In barley, calcium affects the K_m but not the V_max for sulfate uptake, presumably by altering the conformation and, thereby, the affinity of the carrier. Calcium also affects the transition site for sulfate uptake.     

Isolation of six microsatellite loci in the pollinating fig wasp,Platyscapa awekei

Platyscapa awekei DNA was enriched for several repeat motifs. Sequencing of 48 transformed colonies showed that 22 contained microsatellite loci. Eleven of these loci were tested and six of them proved to be reliable and variable. As expected from these wasps’ biology, F_IS was high (= 0.423), indicating frequent sibmating. Notwithstanding, we estimate that dispersing males may secure as much as 8% of all matings.     

Constitutive Uptake of Choline Sulfate by Roots and Leaf Slices of Barley

Barley roots take up choline sulfate constitutively via 3 separate, homogeneous mechanisms which obey Michaelis-Menten kinetics and have, respectively, low, high, and very high affinity for the sulfate ester. Leaf slices possess only the low-and the high-affinity mechanism. These are both inhibited by dini-trophenol and NaF but are differently affected by solute analogues. Uptake via the high-affinity mechanism is active; the low-affinity mechanism has also characteristics of facilitated diffusion.     

Six new species of palaeonemerteans (Nemertea) from Hong Kong

One new genus and six new species of palaeonemerteans are described and illustrated from Hong Kong and the New Territories; these are Hubrechtella sinimarinus sp. nov. and Parahubrechtia jillae gen. et sp. nov. in the Hubrechtidae, and Callinera bergendali sp. nov., Carinina sinensis sp. nov., Tubulanus hylbomi sp. nov. and Tubulanus longivasculus sp. nov. in the Tubulanidae. These bring the known number of pa-laeonemertean species from Hong Kong to 11; a key to these species, based primarily upon features distinguishable in the living animals, is provided.     

Non-interactive effects of habitat complexity and adult crayfish on survival and growth of juvenile crayfish (Pacifastacus leniusculus)

1.  In a 1-month outdoor stream channel experiment, we investigated the relative importance of habitat complexity (i.e. cobbled area) and the presence of adult signal crayfish ( Pacifastacus leniusculus ) males on the survival and growth of juveniles.
2.  In treatments with high habitat complexity, more juveniles survived, more were newly moulted and they had a higher specific growth rate (SGR) at the end of the experiment than juveniles in treatments with low habitat complexity. The presence of adult males did not affect survival, moulting stage or growth of the juveniles.
3.  The presence of adult males decreased juvenile activity during night. Juveniles in treatments with low habitat complexity were more active than juveniles in high habitat complexity during both day and night.
4.  There was no difference in total invertebrate biomass between treatments. However, some invertebrate taxa, such as Chironomidae larvae, were affected by habitat complexity or the presence of adult crayfish. Juvenile crayfish in all channels had consumed detritus, algae and Chironomidae larvae and there were no differences in gut contents or stable isotope signals (carbon and nitrogen) between treatments, indicating a similar diet among the juveniles across treatments. However, the biomass of chironomids was significantly higher in channels with adult crayfish present, indicating a decreased consumption of chironomids by juveniles in the presence of adults.
5.  Our results suggest that the recruitment of juvenile crayfish is mostly affected by habitat complexity. The competition for food and shelter and aggressive interactions between the juveniles were most pronounced in low habitat complexity, indicating that habitats with a good access to shelter will enhance recruitment of juvenile crayfish in streams.