The family Erinaceidae: a synthesis of its taxonomy, phylogeny, ecology and zoogeography

All species and higher taxa of Recent Erinaceidae are diagnosed, the character-states most useful in classification are tabulated and the most probable phylogenies presented. Four African species are included in the genus Atelerix. The desert-adapted Paraechinus is believed to be more closely related to Atelerix than to the convergent Hemiechinus. The ranges of all species are mapped, with emphasis upon areas of parapatry and sympatry. Marginal localities are listed if they are not derived from previously published maps. All nominal fossil species that have been allocated to Recent genera are listed. Ecological data relevant to the interpretations of species boundaries, e.g. relating to diet and habitat, are summarized, and the factors likely to determine the species boundaries are reviewed.     

Proposed new realignments in the angiosperms

Our attempt at putatively phylogenetic classifications of Angiospermae, considering our vast ignorance of more than 120 million years of evolution of the class, must be very tentative and elastic to make full use of the new approaches and new data constantly being made available to us. Some of the realignments thus required in my system of classification are here explained. Among others, the Paeoniales are recognized and include Glaucidiaceae; various shifts of families are made within Thei–florae–Violiflorae–Malviflorae; Thymelaeaceae and Simmondsiaceae are transferred to Euphorbiales; Emblingiaceae, Gyrostemonaceae and Bataceae are added to Sapindineae; Fabineae, with Connaraceae, Surianaceae and Fabaceae, are transferred to Rutiflorae; Proteiflorae are placed near Rutiflorae, especially Fabineae; the largely Australasian–African Pittosporales are explained; Cornaceae are severely pruned; Haemodoraceae and Velloziaceae are transferred to Commelinales; Arecales, Cyclanthales and Pandanales are separated into unrelated superorders; and Typhiflorae are moved into closer proximity with Commeliniflorae.     

中国缩颜蚜蝇族种类记述及地理分布(双翅目:食蚜蝇科)

本文记述了我国双翅目食蚜蝇科缩颜蚜蝇族6属23种,其中有5新种2新纪录属13新纪录种,列出了属、种检索表,并对新种进行了形态描述,同时,对此族的地理分布、区系及起源进行了初步探讨。     

Arteriovenous malformations of the brain: a teratologic challenge

Congenital arteriovenous malformations of the brain are lesions which are well-known to neurologists and neurosurgeons but are puzzling to teratologists because they occur sporadically and are unassociated with congenital malformations outside the central nervous system. They are recommended to teratologists as a field of etiologic and pathogenetic research.     

Scaling of Folding Properties in Go Models of Proteins

Insights about scaling of folding properties of proteins are obtained bystudying folding in heteropolymers described by Go-like Hamiltonians. Bothlattice and continuum space models are considered. In the latter case, themonomer-monomer interactions correspond to the Lennard-Jones potential.Several statistical ensembles of the two- and three-dimensional targetnative conformations are considered. Among them are maximally compactconformations which are confined to a lattice and those which are obtainedeither through quenching or annealing of homopolymers to their compactlocal energy minima. Characteristic folding times are found to grow aspower laws with the system size. The corresponding exponents are notuniversal. The size related deterioration of foldability is found to beconsistent with the scaling behavior of the characteristic temperatures:asymptotically, the folding temperature becomes much lower than thetemperature at which glassy kinetics become important. The helicalconformations are found to have the lowest overall scaling exponent andthe best foldability among the classes of conformations studied. Thescaling properties of the Go-like models of the protein conformationsstored in the Protein Data Bank suggest that proteins are not optimizedkinetically.     

Linear rank tests for interval-censored data with application to PCB levels in adipose tissue of transformer repair workers

Linear rank statistics are described for testing for differences between groups when the data are interval-censored. The statistics are closely related to those described by Prentice (1978, Biometrika 65, 167-179) for right-censored data. Problems in calculating the statistics are discussed and several approaches to computation including estimation of the efficient rank scores are described. Results from a small simulation study are presented. The methods are applied to data from a study relating tissue levels of PCBs to occupational exposure.     

Paraffin Embedding; a Graded-Temperature Table Used with Multiple Blocking for Enhanced Efficiency

Details are given for the construction of a graded-temperature table having a cool and hot side. Aluminum baking pans smeared with glycerol are used to cast the multiple paraffin blocks. These are loaded with paraffin wax from an electrically heated paraffin wax dispenser incorporated in the graded-temperature table and the pieces of tissue and labels orientated in them. The pans are then moved to the cool side of the table before finally floating them on cold water to harden the wax. Arranged above the heated side of the table are two infrared lamps which prevent premature solidification of the surface of the wax. After removing the solid, multiple-block slabs from the pans, the infrared lamps are used to soften the wax to a cheese-like consistency. Individual blocks are cut apart and trimmed around their sides with single strokes to produce smooth-sided blocks which are ready for attaching to wooden holders, adapted to the microtome chuck.     

峨眉山蕨类植物区系的初步研究

依据2004~2006年的野外调查和标本馆标本以及文献资料,初步分析了峨眉山蕨类植物区系的地理特征,结果表明:峨眉山共有蕨类植物46科110属425种,优势科为蹄盖蕨科、水龙骨科和鳞毛蕨科,共192种,占总种数45.2%,优势属为耳蕨属、鳞毛蕨属、凤尾蕨属和蹄盖蕨属等;在科、属的水平上,为热带分布型,以泛热带分布为主,而种的地理分布则以温带分布的中国特有和东亚成分占绝对优势,分别为36.5%和32.0%,揭示了峨眉山蕨类植物区系是以温带性质为主的亚热带类型,具有较强的热带亲缘;与大巴山关系密切,和云南哀牢山有一定的联系,而与秦岭、西藏和陕西天华山的关系较为疏远。     

Wood, bark and stem anatomy of New World species of Gnetum

Quantitative and qualitative data are presented for 11 collections of six species. The wide range of character states for the species is presented in the form of a key to emphasize their potential systematic correlations. Distinctive among these are phcllem characteristics. Fibre-tracheids are newly reported for lianoid Gnetum species. Cells previously thought to be like companion cells in secondary phloem are shown to be uniseriate rays, counterparts to uniseriate xylem rays. Laticifers are abundant in most of the species, and are newly described for secondary tissues of Gnetum. Presence of tyloses in laticifers of two species is apparently a new report for vascular plants. Tori are present in two New World Gnetum species, adding to the report in African species. Perforation plates are simple except near or in primary xylem, where they are simple or foraminate. Torus presence and foraminate perforation plate presence are features more reminiscent of Ephedra and other gymnosperms than of angiosperms. The bark of Gnetum is also very similar to that of Ephedra.     

A review of criticisms of phylogenetic nomenclature: is taxonomic freedom the fundamental issue?

The proposal to implement a phylogenetic nomenclatural system governed by the PhyloCode), in which taxon names are defined by explicit reference to common descent, has met with strong criticism from some proponents of phylogenetic taxonomy (taxonomy based on the principle of common descent in which only clades and species are recognized). We examine these criticisms and find that some of the perceived problems with phylogenetic nomenclature are based on misconceptions, some are equally true of the current rank-based nomenclatural system, and some will be eliminated by implementation of the PhyloCode. Most of the criticisms are related to an overriding concern that, because the meanings of names are associated with phylogenetic pattern which is subject to change, the adoption of phylogenetic nomenclature will lead to increased instability in the content of taxa. This concern is associated with the fact that, despite the widespread adoption of the view that taxa are historical entities that are conceptualized based on ancestry, many taxonomists also conceptualize taxa based on their content. As a result, critics of phylogenetic nomenclature have argued that taxonomists should be free to emend the content of taxa without constraints imposed by nomenclatural decisions. However, in phylogenetic nomenclature the contents of taxa are determined, not by the taxonomist, but by the combination of the phylogenetic definition of the name and a phylogenetic hypothesis. Because the contents of taxa, once their names are defined, can no longer be freely modified by taxonomists, phylogenetic nomenclature is perceived as limiting taxonomic freedom. We argue that the form of taxonomic freedom inherent to phylogenetic nomenclature is appropriate to phylogenetic taxonomy in which taxa are considered historical entities that are discovered through phylogenetic analysis and are not human constructs.     

Targeting of membrane proteins to endosomes and lysosomes

The pathways involved in targeting membrane proteins to lysosomes are extraordinarily complex. Newly synthesized proteins in the ER are transported to the Golgi complex, and upon arrival at the trans Golgi network (TGN) are targeted either directly to endosomes, or first to the cell surface from where they can be rapidly internalized into the endocytic pathway for delivery to lysosomes. The routes to endosomes are specified by sorting motifs in the cytoplasmic tails of the proteins that are recognized at the TGN or plasma membrane. The molecular details of these processes are just emerging.     

Estimates of a Treatment Effect Based on Censored Data Rank Tests

Linear rank test statistics are applied to the problem of estimating a treatment effect if two sets of censored failure time data are compared and the distributions of the log-failure times of the two samples are assumed to differ only in location. Rank tests for this accelerated failure time model are reviewed and Hodges-Lehmann type estimates for the shift parameter are proposed. Properties of these estimates are investigated, computational aspects are discussed and an example is presented.     

Two arms are better than one: parasite variation leads to combined inducible and constitutive innate immune responses

Parasites represent a major threat to all organisms which has led to the evolution of an array of complex and effective defence mechanisms. Common to both vertebrates and invertebrates are innate immune mechanisms that can be either constitutively expressed or induced on exposure to infection. In nature, we find that a combination of both induced and constitutive responses are employed by vertebrates, invertebrates and, to an extent, plants when they are exposed to a parasite. Here we use a simple within-host model motivated by the insect immune system, consisting of both constitutive and induced responses, to address the question of why both types of response are maintained so ubiquitously. Generally, induced responses are thought to be advantageous because they are only used when required but are too costly to maintain constantly, while constitutive responses are advantageous because they are always ready to act. However, using a simple cost function but with no a priori assumptions about relative costs, we show that variability in parasite growth rates selects for a strategy that combines both constitutive and induced defences. Differential costs are therefore not necessary to explain the adoption of both forms of defence. Clearly, hosts are likely to be challenged by variable parasites in nature and this is sufficient to explain why it is optimal to deploy both arms of the innate immune system.     

Nosocomial lung infections in adult intensive care units

Nosocomial respiratory tract infections are the leading type of nosocomial infections. Despite the development of new antibiotic therapies, they are associated with an increased morbidity and mortality. Patients with comorbidities are especially predisposed to acquire these infections, as are patients exposed to respiratory therapy. Aspiration of colonized secretions from the oropharynx is the main mechanism of infection development. Barrier techniques to reduce aspiration and antimicrobial agents to alter bacterial flora are important in preventing pneumonia episodes. The initial institution of an adequate antibiotic regimen is a determinant of outcome. Nosocomial pneumonias are often difficult to treat due to antibiotic-resistant bacteria. Antibiotic policies are crucial in avoiding a progression in antibiotic resistance.     

Cell surface proteins and malignant transformation

Many of the altered properties of malignant cells are thought to involve alterations in cell surface functions. In order to understand these alterations it is necessary to know more about the molecular structure of the surface. Methods for analyzing surface proteins are discussed and their application to normal and transformed tissue culture cells are reviewed. A number of surface proteins are observed to be altered by transformation. Most of the alterations are reductions in amounts of particular species, although a few proteins do increase. Evidence concerning the reasons for these alterations and the possible functions of some of the molecules is reviewed. Working hypotheses arising from these data are presented and prospects for understanding the physiological changes in terms of molecular effects are discussed. Particular emphasis is placed on the idea that surface molecules are associated in specific-non-covalent complexes which are important for their functions.     

Free and membrane-bound chloroplast polyribosomes Chlamydomonas reinhardtii.

Over half of the chloroplast ribosomes isolated from growing cultures of Chlamydomonas reinhardtii are bound to chloroplast thylakoid membranes if completion of nascent polypeptide chains is prevented by chloramphenicol. The free chloroplast ribosomes are recovered in homogenate supernatants, and presumably originate from the chloroplast stroma. Only about 10% of these free chloroplast ribosomes are polyribosomes, even under conditions when 70% of free cytoplasm ribosomes are recovered as polyribosomes. The nonionic detergent Nonidet P-40 liberates atypical polyribosomes (Type I), from membranes, which require both ribonuclease and proteases for complete conversion to monomeric ribosomes. Thus Type I particles are held together by mRNA but are also held together by peptide bonds. These Type I polyribosomes probably are not bound to intact membrane, but might be bound to some protein-containing sub-membrane particle. The Type I polyribosomes are dissociated to ribosomal subunits by puromycin and high salt, and contained 0.2 to 1 nascent chain per ribosome. If membranes are treated with Nonidet and proteases at the same time, polyribosomes which are digested to monomeric ribosomes by ribonuclease alone (Type II) are obtained. Type II polyribosomes are smaller than Type I, and probably represent the true size distribution of polyribosomes on the membranes. At least 50% of the membrane-bound ribosomes are polyribosomes, since that much membrane bound chloroplast RNA is recovered as Type I or Type II polyribosomes.     

Lipid-cholesterol interactions. Monte Carlo simulations and theory.

Results of Monte Carlo calculations of order parameter profiles of lipid chains interacting with cholesterol are presented. Cholesterol concentrations in the simulations are sufficiently large that it is possible to analyze profiles for chains which are near neighbors of two or more cholesterol molecules, chains which are neighbors to a single cholesterol, and chains which are not near any cholesterol molecules. The profiles, show that cholesterol acts to significantly decrease the ability of neighboring chains to undergo trans-gauche isomeric rotations, although these chains are not all forced into all-trans conformations. The effect is significantly greater for chains which are neighbors to more than one cholesterol. The Monte Carlo results are next used as a guide to develop a theoretical model for lipid-cholesterol mixtures. The properties of this model and the phase diagram which it predicts are described. The phase diagram is then compared with experimentally determined phase diagrams. The model calculations and the computer simulations upon which they are based yield a molecular mechanism for several of the observed phases exhibited by lipid-cholesterol mixtures. The theoretical model predicts that at low temperatures the system should exhibit solid phase immiscibility.     

Exclusion of chromosomal mosaicism: tables of 90%, 95% and 99% confidence limits and comments on use.

Tables specifically tailored to the exclusion of cytogenetic mosaicism at three confidence levels are presented. The consequences of the assumption of independence in application of the binomial theorem to this question are discussed. The tables are most applicable to the number of cells evaluated from cultures in which all mitoses are arrested in the first in vitro division. For long-term cultures the tables are conservatively applicable to the number of separate colonies evaluated. If n cells have been evaluated from phytohemagglutinin stimulated peripheral blood after 72 hr in cultures, the tables are applicable to between n/2 and n cells.     

Choosing plant cultivars based on the probability of outperforming a check

Summary A major consideration in most plant breeding programs is the development of cultivars that have high probabilities of outperforming the check cultivar in a broad range of environments. Methods are presented for estimating and testing hypotheses regarding these probabilities, which are termed reliabilities. Reliabilities are shown to be directly related to several commonly used stability parameters. Data from international maize yield trials are used to illustrate and evaluate the repeatability of the approach. Results indicate that reliabilities can be useful aids to plant breeders since they (1) are easy to understand and compute, (2) are indices that weigh the importance of the difference in performance relative to stability, and (3) are potentially useful as genetic parameters since they are generally repeatable across randomly sampled sets of environments.Contribution from the Agricultural Research Division, University of Nebraska, Lincoln, Neb., Paper no. 9653     

In vivo and ex vivo regulation of bacterial virulence gene expression

Bacteria are remarkably adaptable organisms that are able to survive and multiply in diverse and sometimes hostile environments. Adaptability is determined by the complement of genetic information available to an organism and by the mechanisms that control gene expression. In general, gene products conferring a growth or survival advantage in a particular situation are expressed, while unnecessary or deleterious functions are not. Expression of virulence gene products that allow pathogenic bacteria to multiply on and within host cells and tissues are no exception to this rule. Being of little or no use to the bacterium except during specific stages of the infectious cycle, these accessory factors are nearly always subject to tight and coordinate regulation. As a result of recent advances, we are beginning to appreciate the complexities of the interactions between bacteria and their hosts. The ability to probe virulence gene regulation in vivo has broadened our perspectives on pathogenesis.