The Use of Acenaphthene in Pollen Tube Technic

A procedure is described for growing pollen tubes in such a manner that a large number of clearly analyzed figures can be obtained. The pollen grains are sown on an artificial medium of sugar, agar, gelatin, and water, the proportions of each varying with the species of pollen grain used. The medium is smeared on the slide while still hot to insure a thin covering, and the pollen grains are dusted on when the medium has sufficiently cooled and hardened. The slides are placed in a staining dish provided with slide slots and a cover, the inside of the cover and the bottom of the dish being lined with moist, but not wet, filter paper. Acenapthene crystals are lightly sprinkled on the bottom of the dish. The developing pollen tubes are thus exposed to the fumes given off by these crystals with consequent disturbance to the spindle mechanism. As a result, the chromosomes are not crowded on a metaphase plate but are widely separated in the tube facilitating any observations to be made.     

Surface fine structure of the subfornical organ in the Japanese quail,Coturnix coturnix japonica

The surface ultrastructure of the subfornical organ (SFO) was investigated in the Japanese quail. The SFO consists of a body and a stalk. The body of the SFO can be divided into rostral and caudal parts. On the rostral part, each ependymal cell possesses a short central solitary cilium; clustered cilia are also occasionally seen. Microvilli are abundant. On the caudal part, cells with a solitary cilium are fewer in number, and clustered cilia are rarely found. Microvilli are not as abundant as on the rostral part. In addition, large bulbous protrusions, tufts of small protrusions, deep funnel-shaped hollows, small pinocytotic invaginations and possible cerebrospinal fluid-contacting axons are sporadically observed on the surface of various regions of the body. Each ependymal cell of the stalk has a wide apical surface. A central solitary cilium, microvilli and other structures are observed more rarely on the stalk than on the body, while clustered cilia are not seen on the stalk. These structures are compared with those of the mammalian SFO and further discussed in relation to the possible dipsogenic receptor function for angiotensin II.     

Sphingomyelinases: enzymology and membrane activity

This paper reviews our present knowledge of sphingomyelinases as enzymes, and as enzymes acting on a membrane constituent lipid, sphingomyelin. Six types of sphingomyelinases are considered, namely acidic, secretory, Mg(2+)-dependent neutral, Mg(2+)-independent neutral, alkaline, and bacterial enzymes with both phospholipase C and sphingomyelinase activity. Sphingomyelinase assay methods and specific inhibitors are reviewed. Kinetic and mechanistic studies are summarized, a kinetic model and a general-base catalytic mechanism are proposed. Sphingomyelinase-membrane interactions are considered from the point of view of the influence of lipids on the enzyme activity. Moreover, effects of sphingomyelinase activity on membrane architecture (increased membrane permeability, membrane aggregation and fusion) are described. Finally, a number of open questions on the above topics are enunciated.     

Emergence of individual behaviour at the population level. Effects of density-dependent migration on population dynamics

The aim of this work is to study the effects of different individual behaviours on the overall growth of a spatially distributed population. The population can grow on two spatial patches, a source and a sink, that are connected by migrations. Two time scales are involved in the dynamics, a fast one corresponding to migrations and a slow one associated with the local growth on each patch. Different scenarios of density-dependent migration are proposed and their effects on the population growth are investigated. A general discussion on the use of aggregation methods for the study of integration of different ecological levels is proposed.     

Phoretic mites associated with animal and human decomposition

Phoretic mites are likely the most abundant arthropods found on carcases and corpses. They outnumber their scavenger carriers in both number and diversity. Many phoretic mites travel on scavenger insects and are highly specific; they will arrive on a particular species of host and no other. Because of this, they may be useful as trace indicators of their carriers even when their carriers are absent. Phoretic mites can be valuable markers of time. They are usually found in a specialised transitional transport or dispersal stage, often moulting and transforming to adults shortly after arrival on a carcase or corpse. Many are characterised by faster development and generation cycles than their carriers. Humans are normally unaware, but we too carry mites; they are skin mites that are present in our clothes. More than 212 phoretic mite species associated with carcases have been reported in the literature. Among these, mites belonging to the Mesostigmata form the dominant group, represented by 127 species with 25 phoretic mite species belonging to the family Parasitidae and 48 to the Macrochelidae. Most of these mesostigmatids are associated with particular species of flies or carrion beetles, though some are associated with small mammals arriving during the early stages of decomposition. During dry decay, members of the Astigmata are more frequently found; 52 species are phoretic on scavengers, and the majority of these travel on late-arriving scavengers such as hide beetles, skin beetles and moths. Several species of carrion beetles can visit a corpse simultaneously, and each may carry 1–10 species of phoretic mites. An informative diversity of phoretic mites may be found on a decaying carcass at any given time. The composition of the phoretic mite assemblage on a carcass might provide valuable information about the conditions of and time elapsed since death.     

Designing selective sites in templated polymers utilizing coordinative bonds

This review gives a survey over recent achievements on the design of selective sites in templated polymers. Particularly, coordinative bonds as driving force for the interaction between a substrate and a templated polymer are discussed. Recent achievements on the selective recognition of larger molecules, such as dipeptides and disaccharides, are highlighted that promise a fast development on biomolecule templated material towards enzyme-like catalysis in the up-coming years. Additionally, the achievements on the incorporation of catalytic centers based on transition metal complexes are summarized.     

Use of surname models in human population biology: a review of recent developments

Since 1985, when a bibliography concerning studies on surnames and genetic structure appeared, the number of publications on this subject has increased a thousandfold. New topics and uses have been added, but large gaps in knowledge remain. Only studies on isonymy in cities of nation states for recent times are well covered, and most studies are on populations that were selected because they are isolated and not because they are typical. This review, although not exhaustive, covers the literature published since 1985.     

An account of the Chalcidoidea (Hymenoptera) parasitising leaf-mining insects of deciduous trees in Britain

Data on the distribution and frequency of hymenopterous parasites of leaf-mining insects on deciduous trees show that Chalcidoidea of the family Eulophidae are the chief component of the parasite faunas. The regular parasite complement of a leaf-mining species is in the order of 10 to 20 species of parasitic Hymenoptera. Many of these are polyphagous, but in almost all instances a preference for a particular type of host is evident. The parasite faunas of tree leaf-mining Lepidoptera, Coleoptera and Hymenoptera are shown to be qualitatively similar, but those of Diptera are rather different. The parasite faunas of tree leaf-miners are different also from those of leaf gall-forming insects on trees and, to a lesser degree, from those of leaf-miners on herbaceous plants. The parasite fauna associated with a tree genus is quantitatively and qualitatively characteristic and, in general, it most resembles that found on allied tree genera. Congeneric leaf miners attacking the same tree species are attacked by very similar parasite faunas, although mine situation and season of development may exert some influence. These latter factors are considered especially in relation to leaf-miners of the genus Phyllonorycter for which most data are available.     

Robust indices of Hardy-Weinberg disequilibrium for QTL fine mapping

Hardy-Weinberg disequilibrium (HWD) measures have been proposed using dense markers to fine map a quantitative trait locus (QTL) to regions < approximately 1 cM. Earlier HWD measures may introduce bias in the fine mapping because they are dependent on marker allele frequencies across loci. Hence, HWD indices that do not depend on marker allele frequencies are desired for fine mapping. Based on our earlier work, here we present four new HWD indices that do not depend on marker allele frequencies. Two are for use when marker allele frequencies in a study population are known, and two are for use when marker allele frequencies in a study population are not known and are only known in the extreme samples. The new measures are a function of the genetic distance between the marker locus and a QTL. Through simulations, we investigated and compared the fine mapping performance of the new HWD measures with that of the earlier ones. Our results show that when marker allele frequencies vary across loci, the new measures presented here are more robust and powerful.     

Dose limits for occupational exposure to ionising radiation and genotoxic carcinogens: a German perspective

This paper summarises the view of the German Commission on Radiological Protection (“Strahlenschutzkommission”, SSK) on the rationale behind the currently valid dose limits and dose constraints for workers recommended by the International Commission on Radiological Protection (ICRP). The paper includes a discussion of the reasoning behind current dose limits followed by a discussion of the detriment used by ICRP as a measure for stochastic health effects. Studies on radiation-induced cancer are reviewed because this endpoint represents the most important contribution to detriment. Recent findings on radiation-induced circulatory disease that are currently not included in detriment calculation are also reviewed. It appeared that for detriment calculations the contribution of circulatory diseases plays only a secondary role, although the uncertainties involved in their risk estimates are considerable. These discussions are complemented by a review of the procedures currently in use in Germany, or in discussion elsewhere, to define limits for genotoxic carcinogens. To put these concepts in perspective, actual occupational radiation exposures are exemplified with data from Germany, for the year 2012, and regulations in Germany are compared to the recommendations issued by ICRP. Conclusions include, among others, considerations on radiation protection concepts currently in use and recommendations of the SSK on the limitation of annual effective dose and effective dose cumulated over a whole working life.     

Peculiarities of an electric discharge between an electrolytic cathode and a metal anode

Results from experimental studies of an electric discharge operating between a solid anode and an electrolytic cathode in a wide pressure range are presented. Specific features of the discharge ignition and discharge shape and peculiarities the structure of cathode spots on the electrolyte surface and anode spots on the surface of the solid electrode are revealed. The dependences of the current density on the electrolytic cathode and metal anode on the total current are measured, and the spatial distribution of the electric field is determined. A transition of a glow discharge into a multichannel discharge is investigated. The experimental data on the frequency and amplitude of the current and voltage pulsations are presented. Requirements for the maintenance of an electric discharge with an electrolytic cathode are formulated using the obtained experimental results.     

Phylogenetic position of the Strepsiptera: Review of molecular and morphological evidence

Molecular evidence of the monophyly of the Halteria (Strepsiptera + Diptera) is reviewed. The majority of morphological characters, which have classically been used to establish a Strepsiptera + Coleoptera sister group, are rejected, because they are based on erroneous interpretations of strepsipteran morphology. The scorings of 31 morphological characters, which directly relate to the phylogenetic position of Strepsiptera, are provided, and their distribution and optimization on the molecular + morphological tree is discussed. Of these, 13 characters specifically support the placement of Strepsiptera within the Mecopterida; seven of which are based on the optimization of inapplicable or missing data, and six of which are based on states that can be scored for Strepsiptera. Only a single character (posteromotorism) suggests a sister group relationship with the Coleoptera. The morphological and molecular data are largely congruent, and suggest that the Strepsiptera are sister group to the Diptera.     

Sensilla of the antennae and the labial and maxillary palps of Blattella germanica (L.) (Dictyoptera: Blattellidae): Their classification and distribution

The various sensilla on the antennae and on the labial and maxillary palps of Blattella germanica (L.) were studied. Thick-walled chemoreceptors with fluted shafts and articulated bases are located on the antennae and on the labial and maxillary palps. Thin-walled chemoreceptors, without fluted shafts or articulated bases, are restricted to the flagellar segments of the antennae and to the distal segments of the palps. Antennae of adult males have more thin-walled chemoreceptors than do those of females. Hair-plate sensilla are found at the scape-head and scape-pedicel joints, and at the joints of segments on the palps. Campaniform sensilla are concentrated as a ring around the distal margin of the pedicel, and are also scattered singly on the scape, pedicel, and flagellar segments of the antennae, and on the first segment of the maxillary palps. Occasionally, a few sensilla coeloconica and cold receptor sensilla are found on the antennal flagellum.     

The Bead blot: a method for selecting small molecule ligands for protein capture and purification

We present a new method for selecting peptide ligands that are useful for protein purification, protein targeting and exploring protein-ligand interactions, and which requires no prior protein purification or derivatization. In the Bead blot, a complex mixture containing the target protein, for example, plasma, is incubated with a combinatorial library of peptide ligands synthesized on beads. The proteins are fractionated and purified on their respective ligands and the beads with their bound proteins are immobilized in a gel. The proteins are eluted from the ligands by capillary action and captured on a membrane so that their position on the membrane corresponds to the position of the beads in the gel. The protein is detected on the membrane, generating spots on an autoradiography film, the spots on the film are aligned with the beads in the gel, and the beads that bound the protein are recovered. The ligand on the bead(s) can be sequenced and synthesized at large scale for protein purification. The Bead blot can be completed in several hours with overnight pause steps if desired. On average, 5 prospective ligands are selected per 50,000 beads screened using this method. Unlike other ligand identification methods, the target protein does not have to be purified or labeled, and the Bead blot allows ligands for multiple proteins to be selected in a single experiment.     

Rotary-Shadowed Freeze-Fracture Replicas: A Simple Method for the Analysis of Fracture Faces

In rotary-shadowed freeze-fracture replicas, intramembrane particles on the periphery of a membrane fracture face are not uniformly shadowed from all sides. Those eccentrically positioned intramembrane particles with a net centripetally directed shadowing are on a convex fracture face. In contrast, those eccentrically positioned intramembrane particles with a net centrifugally directed shadowing are on a concave fracture face. Centrally positioned intramembrane particles on convex faces are uniformly shadowed from all sides; however, central depressions of concave faces are often unshadowed.     

Rotary-shadowed freeze-fracture replicas: a simple method for the analysis of fracture faces

In rotary-shadowed freeze-fracture replicas, intramembrane particles on the periphery of a membrane fracture face are not uniformly shadowed from all sides. Those eccentrically positioned intramembrane particles with a net centripetally directed shadowing are on a convex fracture face. In contrast, those eccentrically positioned intramembrane particles with a net centrifugally directed shadowing are on a concave fracture face. Centrally positioned intramembrane particles on convex faces are uniformly shadowed from all sides; however, central depressions of concave faces are often unshadowed.     

睡眠研究中相关动物选择的进展

在睡眠研究使用的各种实验动物中,除了常用的啮齿类动物,还有猫、果蝇、猴和斑马鱼等.啮齿类动物因制作其睡眠相关的模型简便易行而得到广泛的应用,主要是采用各种物理化学方法制作失眠动物模型;转基因小鼠主要应用于药物干预睡眠及睡眠发生机制的研究;果蝇和斑马鱼多用于遗传学中睡眠的研究;猫用于睡眠研究的历史悠久,多用于体内试验,对内源性神经递质进行定量分析;猴睡眠结构与人相似,被广泛用于神经生物学,行为药理学等领域与睡眠的关系研究中.由于各种实验动物特殊的生理特征,在睡眠研究中多根据研究目的选择不同的实验动物.     

Phylogenetic study of transcortin using monoclonal antibodies

We produced monoclonal antibodies that recognise three distinct epitopes of human transcortin. These epitopes are present on transcortin of humans with normal and altered transcortin levels, as well as on a variant with lower affinity for cortisol. One epitope is present on transcortin of Old World Monkeys and apes, the others are only present on transcortin of apes. The epitopes are not present on transcortin of other species. These results indicate that human transcortin contains a highly evolved and a more conserved part.     

基因型错误对数量性状精细定位的哈迪-温伯格不平衡指数的效应

使用紧密相邻的标记位点且与标记基因频率无关的哈迪-温伯格不平衡(HWD)指数被用来对数量性状位点(QTL)进行精细定位.本文讨论了当存在基因型错误时HWD指数的性质.文章指出,当存在基因型错误时,对于在群体的标记基因频率已知的情形使用的两个HWD指数尽管受基因型错误的影响但仍然有效;而仅仅极端样本的标记基因频率已知的情形下使用的两个HWD指数同时与基因型错误和标记基因频率有关.计算机模拟表明,仅仅极端样本的标记基因频率已知的情形下使用的两个HWD指数在精细定位时会产生偏差,不适宜作精细定位.