Comparative 3D quantitative analyses of trapeziometacarpal joint surface curvatures among living catarrhines and fossil hominins

Comparisons of joint surface curvature at the base of the thumb have long been made to discern differences among living and fossil primates in functional capabilities of the hand. However, the complex shape of this joint makes it difficult to quantify differences among taxa. The purpose of this study is to determine whether significant differences in curvature exist among selected catarrhine genera and to compare these genera with hominin¹ fossils in trapeziometacarpal curvature. Two 3D approaches are used to quantify curvatures of the trapezial and metacarpal joint surfaces: (1) stereophotogrammetry with nonuniform rational B‐spline (NURBS) calculation of joint curvature to compare modern humans with captive chimpanzees and (2) laser scanning with a quadric‐based calculation of curvature to compare modern humans and wild‐caught Pan, Gorilla, Pongo, and Papio. Both approaches show that Homo has significantly lower curvature of the joint surfaces than does Pan. The second approach shows that Gorilla has significantly more curvature than modern humans, while Pongo overlaps with humans and African apes. The surfaces in Papio are more cylindrical and flatter than in Homo. Australopithecus afarensis resembles African apes more than modern humans in curvatures, whereas the Homo habilis trapezial metacarpal surface is flatter than in all genera except Papio. Neandertals fall at one end of the modern human range of variation, with smaller dorsovolar curvature. Modern human topography appears to be derived relative to great apes and Australopithecus and contributes to the distinctive human morphology that facilitates forceful precision and power gripping, fundamental to human manipulative activities. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc. ¹ The term “hominin” refers to members of the tribe Hominini, which includes modern humans and fossil species that are related more closely to modern humans than to extant species of chimpanzees, Wood and Lonergan (2008). Hominins are in the family Hominidae with great apes.     

Monte Carlo integration over stepping stone models for spatial genetic inference using approximate Bayesian computation

Approximate Bayesian computation (ABC) substitutes simulation for analytic models in Bayesian inference. Simulating evolutionary scenarios under Kimura’s stepping stone model (KSS) might therefore allow inference over spatial genetic process where analytical results are difficult to obtain. ABC first creates a reference set of simulations and would proceed by comparing summary statistics over KSS simulations to summary statistics from localities sampled in the field, but: comparison of which localities and stepping stones? Identical stepping stones can be arranged so two localities fall in the same stepping stone, nearest or diagonal neighbours, or without contact. None is intrinsically correct, yet some choice must be made and this affects inference. We explore a Bayesian strategy for mapping field observations onto discrete stepping stones. We make Sundial, for projecting field data onto the plane, available. We generalize KSS over regular tilings of the plane. We show Bayesian averaging over the mapping between a continuous field area and discrete stepping stones improves the fit between KSS and isolation by distance expectations. We make Tiler Durden available for carrying out this Bayesian averaging. We describe a novel parameterization of KSS based on Wright’s neighbourhood size, placing an upper bound on the geographic area represented by a stepping stone and make it available as m Vector. We generalize spatial coalescence recursions to continuous and discrete space cases and use these to numerically solve for KSS coalescence previously examined only using simulation. We thus provide applied and analytical resources for comparison of stepping stone simulations with field observations.     

Spectrophotometric determination of peptide transport with chromogenic peptide mimetics

A spectrophotometric assay to determine peptide transport has been developed. Using two chromogenic peptide mimetics, L-phenylalanyl-L-2-sulfanilylglycine (PSG) and L-phenylalanyl-L-3-thiaphenylalanine (PSP), the peptide transport patterns in individual cell species can be evaluated effectively. After the addition of PSG to a HeLa cell suspension, sulfanilic acid accumulated progressively inside, but not outside, the cells, demonstrating that PSG was transported wholly intact. The addition of PSP to the same cell suspension was followed immediately by extracellular thiophenol production. Measurement of the rate of thiophenol release thereby provided direct determination of PSP transport. The thiophenol release was consistent with Michaelis-Menten kinetics, with a K(m) of 0.016 mM and a V(max) of 5.07 nmol/min (1 x 10(6) cells/ml, pH 7.4, 37 degrees C). The resulting kinetic constants estimated were in agreement with values determined by single-substrate enzyme kinetics. Using PSP, transport kinetics of various dipeptides was examined by competitive spectrophotometry. As a result, dipeptides tested could be ranked in order of kinetic power for their transport.     

The influence of artificial cranial vault deformation on the expression of cranial nonmetric traits: its importance in the study of evolutionary relationships

Nonmetric cranial traits have been commonly used in evolutionary relationship studies. They develop during the growth and development of an individual, and for this reason its expression presents different sources of genetic and nongenetic variation. However, the use of these features in evolutionary relationship studies carries the implicit assumption that much of the nonmetric trait variation is essentially genetic. Among the nonheritable factors, cranial vault deformation has been the most studied in human populations. Because of the widespread distribution and elevated rate of artificial cranial vault deformation found in America, and the importance of nonmetric traits in evolutionary relationship studies in this area, the objectives of this paper are as follows: (a) to study the influence of artificial cranial vault deformation on the presence of nonmetric traits within samples of human craniofacial remains; and (b) to establish artificial cranial vault deformation influence on evolutionary relationships between local populations on a regional scale. Our results indicate that artificial cranial vault deformations alter the variation and covariation of metric and nonmetric traits in some samples. Wormian bones, placed in cranial vault sutures, are the most influenced by this factor. However, our results suggest that when all nonmetric traits were used the artificial cranial vault deformation did not influence the basic pattern of variation among samples. The exclusion or inclusion of wormians bones in evolutionary relationships analysis did not modify the results, but using only wormians bones lead to inconsistent results indicating that these traits have little value on these kind of studies.     

纺织基人造血管几何特征表征的实验研究

人造血管的壁厚和松弛内径是其主要的几何特征参数。本文中首先依据国际标准ISO 7198的要求设计了测试人造血管松弛内径的测试定规,并对人造血管样品进行了测试。然后对人造血管壁厚的测试方法进行了初步探讨。     

Where do these bugs come from? Phenotypic structure of Triatoma infestans populations after control interventions in the Argentine Chaco

House re-invasion by native triatomines after insecticide-based control campaigns represents a major threat for Chagas disease vector control. We conducted a longitudinal intervention study in a rural section (Area III, 407 houses) of Pampa del Indio, northeastern Argentina, and used wing geometric morphometry to compare pre-spray and post-spray (re-infestant bugs) Triatoma infestans populations. The community-wide spraying with pyrethroids reduced the prevalence of house infestation by T. infestans from 31.9% to < 1% during a four-year follow-up, unlike our previous studies in the neighbouring Area I. Two groups of bug collection sites differing in wing shape variables before interventions (including 221 adults from 11 domiciles) were used as a reference for assigning 44 post-spray adults. Wing shape variables from post-spray, high-density bug colonies and pre-spray groups were significantly different, suggesting that re-infestant insects had an external origin. Insects from one house differed strongly in wing shape variables from all other specimens. A further comparison between insects from both areas supported the existence of independent re-infestation processes within the same district. These results point to local heterogeneities in house re-infestation dynamics and emphasise the need to expand the geographic coverage of vector surveillance and control operations to the affected region.     

基于几何形态测量学的五种稻蝗前后翅的形态变化研究

【目的】定量分析5种常见稻蝗属昆虫前后翅的形态变化规律。【方法】运用几何形态测量学方法对5种稻蝗雄性前、后翅进行量化分析,并结合主成分分析法(Principal component analysis,PCA)和薄片样条(Thin-plate spline,TPS)分析法探讨稻蝗前后翅的大小和形态变异。【结果】5种稻蝗前、后翅的大小和形态差异都比较显著,前、后翅的相似关系和5种稻蝗的系统发育关系一致。前翅差异的部位主要在缘前脉域、前缘脉域和臀脉域;后翅的差异主要在亚前缘脉域、前缘脉域及轭脉域。【结论】稻蝗前、后翅形态变化的几何形态测量学分析结果与稻蝗系统发育关系一致,可用于稻蝗属种的分类。稻蝗前、后翅发生变化的部位是其飞行时的受力部位,这些部位可以作为稻蝗物种分类特征。     

基于几何形态测量学的黄蜻翅的雌雄二态性研究

【目的】本研究运用几何形态测量学方法对黄蜻Pantala flavescens Fabricius前翅和后翅的雌雄二态性进行分析,探讨黄蜻雌雄性在翅上的形态差异。【方法】通过对黄蜻的前翅和后翅做数字化标点,获得翅的形态信息。经主成分分析(PCA)和薄片样条法(TPS)获得雌雄性在翅型和翅脉上的差异性。【结果】PCA结果表明,黄蜻雌雄性的前翅和后翅在翅型、翅脉结构上存在着明显差异,而且后翅间的差异更大。经TPS分析可知,雌雄性黄蜻前翅上的差异部位主要发生在亚翅结和三角室,后翅的差异部位主要发生在亚翅结、肘脉域和臀角区域。对黄蜻前后翅的大小分析(CS)可知,雌性黄蜻前后翅较大,雄性黄蜻前后翅较小。【结论】黄蜻雌雄性间的翅型结构差异性表明雌雄性在其各自生活史中履行不同的职责,特定的飞行模式逐渐形成特定的翅型、翅脉结构。     

Comparison of topological clustering within protein networks using edge metrics that evaluate full sequence,full structure,and active site microenvironment similarity

The development of accurate protein function annotation methods has emerged as a major unsolved biological problem. Protein similarity networks, one approach to function annotation via annotation transfer, group proteins into similarity-based clusters. An underlying assumption is that the edge metric used to identify such clusters correlates with functional information. In this contribution, this assumption is evaluated by observing topologies in similarity networks using three different edge metrics: sequence (BLAST), structure (TM-Align), and active site similarity (active site profiling, implemented in DASP). Network topologies for four well-studied protein superfamilies (enolase, peroxiredoxin (Prx), glutathione transferase (GST), and crotonase) were compared with curated functional hierarchies and structure. As expected, network topology differs, depending on edge metric; comparison of topologies provides valuable information on structure/function relationships. Subnetworks based on active site similarity correlate with known functional hierarchies at a single edge threshold more often than sequence- or structure-based networks. Sequence- and structure-based networks are useful for identifying sequence and domain similarities and differences; therefore, it is important to consider the clustering goal before deciding appropriate edge metric. Further, conserved active site residues identified in enolase and GST active site subnetworks correspond with published functionally important residues. Extension of this analysis yields predictions of functionally determinant residues for GST subgroups. These results support the hypothesis that active site similarity-based networks reveal clusters that share functional details and lay the foundation for capturing functionally relevant hierarchies using an approach that is both automatable and can deliver greater precision in function annotation than current similarity-based methods.