Convenient solid-phase synthesis of oligopeptides using pentacoordinated phosphoranes with amino acid residue as building blocks

The reactive intermediates of pentacoordinated phosphoranes with amino acids (P(5)-AA) as building blocks, which were obtained by the reaction of O-phenylene phosphorochloridate with N,O-bis(trimethylsilyl)amino acids, were linked to a solid-phase support containing a hydroxymethyl polystyrene functional group. The first amino acid residue was coupled to the solid-phase support after washing the resin with organic solvent. Repeating the procedure led to oligopeptides linked on the resin. A series of free oligopeptides including tetra-Gly, di-Val, tri-Val, di-Leu, di-Phe, and Phe-Leu were obtained after cleavage from solid-phase support. The structure of these oligopeptides were determined by IR, (1)H NMR, FAB-MS, and HPLC.     

Biological life support systems for space crews: Some results and prospects

A set of problems of biomedical support for humans in the extreme environment of a space flight is a challenge for space biology and medicine. Designing robust and efficiently functioning life support systems (LSS) is among these problems. The paper gives an overview of the experiments with manned ground-based biological LSS (BLSS) performed in Russia and abroad. The basic data on the photoautotrophic components of BLSS (higher plants) were obtained in a series of experiments conducted on board the orbital complex Mir for 630 days in total and in the Russian segment of the International Space Station (ISS) (a series of experiments with total duration of 820 days). Analysis of the results obtained on Earth and during the space flights leads to the conclusion that some BLSS components, e.g., greenhouses, can be integrated even now into the systems that are currently used for the life support of space crews.     

Climate shifts the interaction web of a marine plankton community

Climatic effects in the ocean at the community level are poorly described, yet accurate predictions about ecosystem responses to changing environmental conditions rely on understanding biotic responses in a food‐web context to support knowledge about direct biotic responses to the physical environment. Here we conduct time‐series analyses with multivariate autoregressive (MAR) models of marine zooplankton abundance in the Northern California Current from 1996 to 2009 to determine the influence of climate variables on zooplankton community interactions. Autoregressive models showed different community interactions during warm vs. cool ocean climate conditions. Negative ecological interactions among zooplankton groups characterized the major warm phase during the time series, whereas during the major cool phase, ocean transport largely structured zooplankton communities. Local environmental conditions (sea temperature) and large‐scale climate indices (El Niño/Southern Oscillation) were associated with changes in zooplankton abundance across the full time series. Secondary environmental correlates of zooplankton abundance varied with ocean climate phase, with most support during the warm phase for upwelling as a covariate, and most support during the cool phase for salinity. Through simultaneous quantitation of community interactions and environmental covariates, we show that marine zooplankton community structure varies with climate, suggesting that predictions about ecosystem responses to future climate scenarios in the Northern California Current should include potential changes to the base of the pelagic food.     

1-Alkyl-2-aryl-4-(1-naphthoyl)pyrroles: new high affinity ligands for the cannabinoid CB1 and CB2 receptors

Two series of 1-alkyl-2-aryl-4-(1-naphthoyl)pyrroles were synthesized and their affinities for the cannabinoid CB(1) and CB(2) receptors were determined. In the 2-phenyl series (5) the N-alkyl group was varied from n-propyl to n-heptyl. A second series of 23 1-pentyl-2-aryl-4-(1-naphthoyl)-pyrroles (6) was also prepared. Several compounds in both series have CB(1) receptor affinities in the 6-30nM range. The high affinities of these pyrrole derivatives relative to JWH-030 (1, R=C(5)H(11)) support the hypothesis that these pyrroles interact with the CB(1) receptor primarily by aromatic stacking.     

Phylogeny and biogeography of the flowering plant genus Styrax (Styracaceae) based on chloroplast DNA restriction sites and DNA sequences of the internal transcribed spacer region

Phylogenetic relationships within the flowering plant genus Styrax were investigated with DNA sequence data from the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) and with chloroplast DNA restriction site data from the genes trnK, rpoC1, and rpoC2. The data sets from each genome were analyzed separately and in combination with parsimony methods. The results strongly support the monophyly of each of the four series of the genus but provide little phylogenetic resolution among them. Reticulate evolution may at least partly explain discordance between the molecular phylogenetic estimates and a prior morphological estimate within series Cyrta. The historical biogeography of the genus was inferred with unweighted parsimony character optimization of trees recovered from a combined ITS and morphological data set, after a series of combinability tests for data set congruence was conducted. The results are consistent with the fossil record in supporting a Eurasian origin of Styrax. The nested phylogenetic position of the South American members of the genus within those from southern North America and Eurasia suggests that the boreotropics hypothesis best explains the amphi-Pacific tropical disjunct distribution occurring within section Valvatae. The pattern of relationship recovered among the species of section Styrax ((western North America + western Eurasia) (eastern North America + eastern Eurasia)) is rare among north-temperate Tertiary forest relicts. The monophyly of the group of species from western North America and western Eurasia provides qualified support for the Madrean-Tethyan hypothesis, which posits a Tertiary floristic connection among the semiarid regions in which these taxa occur. A single vicariance event between eastern Asia and eastern North America accounts for the pattern of relationship among intercontinental disjuncts in series Cyrta.     

Binding of anti-fibronectin to early amphibian ectoderm does not result in inhibition of neural induction under in vitro conditions

Summary Antibodies directed to fibronectin (anti-FN) were injected into the blastocoel of late blastulae of Xenopus laevis. Two animal caps (ectoderm) were isolated, when control embryos reached the early gastrula stage, and were combined with untreated upper blastopore lip in the sandwich method. In two control series fibronectin or Holtfreter solution was injected into the blastocoel. The results of the experiments suggest that neural induction cannot be prevented by binding anti-FN to fibronectin, which covers the blastocoelic side of the ectoderm. The data support the view that extracellular matrix proteins are not themselves responsible for neural induction. However, in comparison with the control series a slight shift of the differentiation pattern in the spinocaudal direction could be observed in the anti-FN series. The possible role of extracellular proteins in the formation of a close juxtaposition of mesodermal and ectodermal target cells as a prerequisite for shortdistance transmission of neural inducers is discussed.     

Phylogenetic systematic assessment of the Aspidobothrea (Platyhelminthes, Neodermata, Trematoda)

Phylogenetic systematic analysis of 20 aspidobothrean taxa using 33 transformation series based in comparative morphology yields three most parsimonious trees with a consistency index of 62%. The trees agree with familial-level relationships of (Rugogastridae (Stichocotylidae (Multicalycidae + Aspidogastridae))) supported by previous phylogenetic systematic assessments, which were based on only 10 transformation series. The analysis does not support completely the current subfamilial classification of the Aspidogastridae: both the Aspidobothriinae [as ( Aspidogaster + Lobatostoma )] and the Cotylaspinae [as Cotylogasteroides + Cotylogaster basiri (( Cotylaspis + Lissemysia ) ( Rohdella ( Lophotaspis ( Multicotyle + Sychnocotyle )))))] are supported as monophyletic groups. Recognizing Rohdellinae, however, would make the Cotylaspinae paraphyletic. The trees support a basal trichotomy of Cotylogaster michaelis + Aspidobothriinae + Cotylaspinae. Within the Aspidogastrinae, Aspidogaster conchicola , type species of the genus, is the sister group of all other species currently placed in the genus + Lobatosoma spp., rendering Aspidogaster paraphyletic.     

Enantioselective synthesis of S-(+)-2beta-carboalkoxy-3alpha-[bis(4-fluorophenyl)methoxy]tropanes as novel probes for the dopamine transporter

Synthesis of a series of pure S-(+)-2beta-carboalkoxy-3alpha-[bis(4-fluorophenyl)methoxy]tropanes (>99% ee) was achieved by employing a chiral amine-induced asymmetric reaction of tropinone with methyl cyanoformate as the key step. In this series, all of the S-(+)-enantiomers were 2-fold more potent than their racemic mixtures and all displayed high-affinity binding for DAT (K(i)=13-40 nM). These data support previous findings of significant divergence in structural requirements for high-affinity DAT binding among tropane-based inhibitors. Furthermore, the 2-substituent in the 3alpha-[bis(4-fluorophenyl)methoxy]tropane series is well tolerated at the DAT but not at SERT (K(i)=690-2040 nM), or muscarinic M(1) receptors (K(i)=133-4380 nM) resulting in highly selective DAT ligands that may provide new leads toward a cocaine-abuse therapeutic.     

Improved activity retention of enzymes deposited on solid supports

Enzymes deposited on solid support usually show good stability when operated in organic solvents. Decreased stability of the enzyme preparations was noticed when low enzyme loadings were used (e.g., with Celite as support; less than 1 mg enzyme/g). It was possible to avoid the activity loss by the addition of an additive which protects the enzyme during the immobilization. Proteins (such as albumin, gelatin, and casein) and poly(ethylene glycol) were effective additives whereas amino acids, monomeric carbohydrates, and polysaccharides had no effect. The amount of additive needed for stabilization was shown to depend on the structure of the support, more additive being required for a support with high porosity. The stabilizing effect was investigated in a series of glyceryl-controlled-pore glass (CPG) with varying specific surface areas (9.5-180 m(2)/g). The minimum addition of albumin, giving full stabilization, on the different supports correlated to a monolayer coverage of the surface, approximately 2-3 mg protein/m(2). The effect of the additive was less pronounced when increasing amounts of enzyme were immobilized (5-40 mg enzyme/g Celite). The effect of the additives was studied using mandelonitrile lyase, but alpha-chymotrypsin and lipase P were also shown to be stabilized. (c) 1993 John Wiley & Sons, Inc.     

Synthesis, chiral separation, and absolute configuration of bis-(N-aryl) atropisomeric triads: 1,2-bis-[4-methyl-2-(thi)oxo-2,3-dihydrothiazol-3-yl]-benzene

In this work, a series of 1,2-bis-[4-methyl-2-(thi)oxo-2,3-dihydrothiazol-3-yl]-benzene has been prepared. These atropisomeric molecular triads were exclusively found to exist in the anti-form. They were separated into enantiomers by liquid chromatography on a chiral support. The absolute configurations of the enantiomers were determined using a chemical correlation method together with chiral chromatography. The barriers to interconversion of the enantiomers were determined.     

Phylogeny of western Mediterranean Leptodirini, with an emphasis on genital characters (Coleoptera: Leiodidae: Cholevinae)

Abstract The tribe Leptodirini (Leiodidae: Cholevinae) is one of the largest radiations of Coleoptera in the subterranean environment. Although subjected to systematic and evolutionary studies, the phylogeny remains poorly understood. We assessed the phylogeny of the western Mediterranean lineages (Iberian Peninsula, Pyrenees and Sardinia) based on a cladistic analysis of fourteen characters of external morphology and twenty characters of the male and female genitalia, studied in 182 species belonging to thirty‐nine genera. We tested the monophyly of the traditional two main divisions of the group (infraflagellates and supraflagellates), as well as that of some ‘phyletic series’. The final matrix contained fifty‐eight terminal taxa, twenty‐four of which had different character state combinations. The strict consensus of the sixty most parsimonious trees recovered a monophyletic Leptodirini, but not their separation into infraflagellates and supraflagellates. The supraflagellates formed a paraphyletic group with respect to the infraflagellates (corresponding to our sampled ‘Speonomus’ series), with Notidocharis sister to all other included Leptodirini, and Speonomidius sister to Leptodirini excluding Notidocharis. The series ‘Spelaeochlamys’, including the Sardinian genera but excluding Pseudochlamys, was recovered as monophyletic with weak support. The ‘Quaestus’ series formed a polytomy with Pseudochlamys plus the ‘Speonomus’ series (including Bathysciola), which was recovered as monophyletic with strong support. Speonomus, Bathysciola, Quaestus and Troglophyes were para‐ or polyphyletic. Our results suggested the respective monophyletic origin of the Leptodirini from the Pyrenees (Pseudochlamys plus the ‘Speonomus’ series) and the Mediterranean coast plus Sardinia (series ‘Spelaeochlamys’). On the contrary, the Leptodirini of the Atlantic north coast of the Iberian Peninsula (series ‘Quaestus’ and ‘Speonomidius’) were not monophyletic.     

Tooth replacement in the bowfin (Amia calva — Holostei)

The dissected tooth bearing bones of 20 specimens of Amia calva (Pisces:Holostei) ranging from the third to tenth season have been examined radiographically and in alizarin red S stained and cleared specimens. Although forms of alternate (1:1) tooth series replacement (sensu Edmund, '60) were frequently observed, even in the youngest, immature specimens, many examples of irregular replacement were recorded. In several bones, the maxillae in particular, series with every third (2:1) or fourth (3:1) tooth replacing were seen and possible patterns of 2:2, were recorded. It is concluded that these data are not consistent with the Zahnreihen concept but support a morphogenic field concept of tooth development.     

Biofiltration of methanol vapor

Biofiltration of solvent and fuel vapors may offer a costeffective way to comply with increasingly strict air emission standards. An important step in the development of this technology is to derive and validate mathematical models of the biofiltration process for predictive and scaleup calculations. For the study of methanol vapor biofiltration, an 8-membered bacterial consortium was obtained from methanol-exposed soil. The bacteria were immobilized on solid support and packed into a 5-cm-diameter, 60-cm-high column provided with appropriate flowmeters and sampling ports. The solid support was prepared by mixing two volumes of peat with three volumes of perlite particles (i.e., peat-perlite volume ratio 2:3). Two series of experiments were performed. In the first, the inlet methanol concentration was kept constant while the superficial air velocity was varied from run to run. In the second series, the air flow rate (velocity) was kept constant while the inlet methanol concentration was varied. The unit proved effective in removing methanol at rates up to 112.8 g h(-1) m(-3) packing. A mathematical model has been derived and validated. The model described and predicted experimental results closely. Both experimental data and model predictions suggest that the methanol biofiltration process was limited by oxygen diffusion and methanol degradation kinetics. (c) 1993 John Wiley & Sons, Inc.     

Kinetic and docking studies of the interaction of quinones with the quinone reductase active site

NAD(P)H/quinone acceptor oxidoreductase type 1 (QR1) protects cells from cytotoxic and neoplastic effects of quinones though two-electron reduction. Kinetic experiments, docking, and binding affinity calculations were performed on a series of structurally varied quinone substrates. A good correlation between calculated and measured binding affinities from kinetic determinations was obtained. The experimental and theoretical studies independently support a model in which quinones (with one to three fused aromatic rings) bind in the QR1 active site utilizing a pi-stacking interaction with the isoalloxazine ring of the FAD cofactor.     

An expanded plastid DNA phylogeny of Orchidaceae and analysis of jackknife branch support strategy

An expanded plastid DNA phylogeny for Orchidaceae was generated from sequences of rbcL and matK for representatives of all five subfamilies. The data were analyzed using equally weighted parsimony, and branch support was assessed with jackknifing. The analysis supports recognition of five subfamilies with the following relationships: (Apostasioideae (Vanilloideae (Cypripedioideae (Orchidoideae (Epidendroideae))))). Support for many tribal-level groups within Epidendroideae is evident, but relationships among these groups remain uncertain, probably due to a rapid radiation in the subfamily that resulted in short branches along the spine of the tree. A series of experiments examined jackknife parameters and strategies to determine a reasonable balance between computational effort and results. We found that support values plateau rapidly with increased search effort. Tree bisection-reconnection swapping in a single search replicate per jackknife replicate and saving only two trees resulted in values that were close to those obtained in the most extensive searches. Although this approach uses considerably more computational effort than less extensive (or no) swapping, the results were also distinctly better. The effect of saving a maximal number of trees in each jackknife replicate can also be pronounced and is important for representing support accurately.     

Complexity is costly: a meta‐analysis of parametric and non‐parametric methods for short‐term population forecasting

Short‐term forecasts based on time series of counts or survey data are widely used in population biology to provide advice concerning the management, harvest and conservation of natural populations. A common approach to produce these forecasts uses time‐series models, of different types, fit to time series of counts. Similar time‐series models are used in many other disciplines, however relative to the data available in these other disciplines, population data are often unusually short and noisy and models that perform well for data from other disciplines may not be appropriate for population data. In order to study the performance of time‐series forecasting models for natural animal population data, we assembled 2379 time series of vertebrate population indices from actual surveys. Our data were comprised of three vastly different types: highly variable (marine fish productivity), strongly cyclic (adult salmon counts), and small variance but long‐memory (bird and mammal counts). We tested the predictive performance of 49 different forecasting models grouped into three broad classes: autoregressive time‐series models, non‐linear regression‐type models and non‐parametric time‐series models. Low‐dimensional parametric autoregressive models gave the most accurate forecasts across a wide range of taxa; the most accurate model was one that simply treated the most recent observation as the forecast. More complex parametric and non‐parametric models performed worse, except when applied to highly cyclic species. Across taxa, certain life history characteristics were correlated with lower forecast error; specifically, we found that better forecasts were correlated with attributes of slow growing species: large maximum age and size for fishes and high trophic level for birds. Synthesis Evaluating the data support for multiple plausible models has been an integral focus of many ecological analyses. However, the most commonly used tools to quantify support have weighted models’ hindcasting and forecasting abilities. For many applications, predicting the past may be of little interest. Concentrating only on the future predictive performance of time series models, we performed a forecasting competition among many different kinds of statistical models, applying each to many different kinds of vertebrate time series of population abundance. Low‐dimensional (simple) models performed well overall, but more complex models did slightly better when applied to time series of cyclic species (e.g. salmon).     

Mowing during rainfall enhances the control of Cirsium arvense

Pastoral farmers in New Zealand have described dramatic demises in populations of the weed Cirsium arvense (L.) Scop., a perennial herb indigenous to Eurasia, following its mowing during rainfall. To test the hypotheses (1) that the mowing of C. arvense during rainfall increases the control of this weed and (2) that the causal organism in this ‘mowing-in-the-rain’ effect is the vascular wilt fungus Verticillium dahliae, two series of field experiments were carried out in C. arvense-infested pastures in New Zealand, one in autumn 2008 (Experiment series 1, 9 farms), and another in spring/summer 2008–2009 (Experiment series 2, 12 farms). The effect of mowing in the rain as compared to mowing in the dry was to reduce the % ground cover of the thistle in the spring following treatment by 21 and 32% in Experiment series 1 and 2, respectively. Correlations of this ‘rain versus dry’ effect with the incidence of V. dahliae in the subterranean parts of C. arvense shoots sampled in each of the two field experiment series provided no statistical evidence that the effect increased with V. dahliae incidence. Thus these experiments provide no support for the hypothesis that V. dahliae is the biological mechanism for the ‘mowing-in-the-rain’ effect. Nevertheless, they do support mowing during rainfall as a simple and effective management tactic for C. arvense.     

Cellular chemical indices of right ventricular protection in children

Summary Myocardial preservation during open heart surgery in children was studied using biopsies of the right ventricle taken at the beginning and end of a bypass with a Tru-Cut biopsy needle. Three assessments were used: (1) semi-quantitative cytochemical grading of Baker's acid haematein reaction, and the distribution of succinate dehydrogenase and myosin ATPase; (2) microdensitometry of the succinate dehydrogenase activity; and (3) quantitative birefringence measurements to assess the response of the myocardial fibres to ATP and calcium. For each assessment, the values at the beginning and end of the bypass were compared. In a series of 42 children, two died in low cardiac output and three others required substantial inotropic support. No patient showed deterioration in the overall cytochemical assessment. Two patients showed deterioration in birefringence, one died and one had low cardiac output. The remaining three patients who had post-operative problems had low birefringence values at the beginning of bypass. Thirty-two patients were used for the microdensitometric assays, one died and three required substantial inotropic support. Succinate dehydrogenase activity decreased significantly during bypass in only two patients. One of these died and the other required substantial inotropic support.