Restriction analysis of the plasmid and chromosomal DNA of the strain Streptomyces fradiae--a producer of neomycin

Plasmid DNA with a molecular weight of 53-55 Md was isolated from Streptomyces fradiae strain 676 producing neomycin on centrifugation of the DNA preparation at the density gradient of cesium chloride-ethidium bromide. The extrachromosomal DNA had 6 recognition sites for Bgl II, more than 13 recognition sites for Bam HI, more than 14 recognition sites for Kpn I, more than 18 recognition sites for Pst I, more than 20 recognition sites for Sac I, more than 21 recognition sites for Pvu II and no recognition sites for Eco RI, Eco RV, Hind III and Sla I.     

分支位点在真核基因受体位点识别中的作用

真核基因受体位点识别是剪接位点识别的一部分,也是基因识别中的重要环节,一直受到研究人员的关注。已有的研究结果显示受体位点的识别与分支位点有关,然而关于分支位点和受体位点识别的关系问题,目前还无人将其作为专门的问题予以深入研究。从受体位点识别出发,选取不同的受体位点序列长度,以神经网络为识别工具,对分支位点在受体位点识别中的作用做了深入研究和分析。实验结果表明,受体位点序列的特征信息集中在分支位点一例,因此分支位点在受体位点识别中具有重要作用。研究结果为受体位点识别问题中序列特征提取提供了依据。     

Nestmate recognition in social wasps: the origin and acquisition of recognition odours

Laboratory studies of nestmate recognition in gynes (potential queens) of the social wasp, Polistes fuscatus, indicate that recognition odours have both a heritable and an environmental component. In addition, both endogenous odours (acquired as brood) and adult-acquired odours appear to mediate nestmate recognition. Heritable and environmental, as well as endogenous and adult-acquired recognition odours, are not additive in their effect on tolerance, suggesting a ‘cue similarity threshold’ model of recognition rather than a model that postulates tolerance continuouusly increasing with increasing degree of similarity between the learned and perceived cue. Young gynes (1·7–71·8 h after emergence) clearly possess recognition odours and there is no evidence that the age of a young gyne affects its expression of recognition odours. The failure of a wasp, isolated from its natal nest at emergence, to recognize its nestmates is due to the disruption of its learning of recognition odours, not to its acquisition of recognition odours. Gynes appear not to learn recognition odours directly from themselves. Young gynes deprived of the opportunity to learn recognition odours from their natal nest treat all gynes as nestmates, regardless of relatedness. This latter result, together with additional evidence, suggests that the ontogeny of nestmate recognition ability involves the development of intolerance to unfamiliar odours rather than the development of tolerance to familiar odours.     

Agnosia.

Object recognition can break down in a variety of ways after brain damage. The resulting different forms of agnosia provide us with useful constraints on theories of normal object recognition. Recent studies suggest a division of labor for the recognition of different types of stimuli (common objects, words, faces, direction of eye gaze, spatial relations among parts of the human body), a high degree of interactivity in the processes underlying object recognition, and the possibility that recognition and awareness of recognition may be neurally distinct.     

Kin Recognition in the largely Solitary Bee,Manuelia postica (Apidae: Xylocopinae)

The recognition of conspecifics is a central issue to social behaviour. In eusocial hymenopterans, kin recognition has been clearly demonstrated. Manuelia postica is a largely solitary bee species in which larvae develop inside individual cells within a nest and remain isolated from conspecifics until the destruction of partitions by adults. Nestmate recognition in M. postica has been previously demonstrated under experimental conditions. Isolation between individuals during development and nestmate recognition ability in adult females make M. postica an ideal species for testing the occurrence of kin recognition capacity in females. Kin recognition was demonstrated through cross‐fostering field experiments involving the single transfer of recently enclosed larvae, and subsequent laboratory recognition bioassays with emerging females. Results suggest kin recognition occurs through self‐referent phenotype matching. Given the basal position of Manuelia in the phylogeny of the Apidae, kin recognition may represent an ancestral recognition mechanism in Apidae species phylogenetically more derived than M. postica.     

The cognitive neuroscience of memory distortion

Memory distortion occurs in the laboratory and in everyday life. This article focuses on false recognition, a common type of memory distortion in which individuals incorrectly claim to have encountered a novel object or event. By considering evidence from neuropsychology, neuroimaging, and electrophysiology, we address three questions. (1) Are there patterns of neural activity that can distinguish between true and false recognition? (2) Which brain regions contribute to false recognition? (3) Which brain regions play a role in monitoring or reducing false recognition? Neuroimaging and electrophysiological studies suggest that sensory activity is greater for true recognition compared to false recognition. Neuropsychological and neuroimaging results indicate that the hippocampus and several cortical regions contribute to false recognition. Evidence from neuropsychology, neuroimaging, and electrophysiology implicates the prefrontal cortex in retrieval monitoring that can limit the rate of false recognition.     

The evolution of species recognition in competitive and mating contexts: the relative efficacy of alternative mechanisms of character displacement

Sympatric divergence in traits affecting species recognition can result from selection against cross‐species mating (reproductive character displacement, RCD) or interspecific aggression (agonistic character displacement, ACD). When the same traits are used for species recognition in both contexts, empirically disentangling the relative contributions of RCD and ACD to observed character shifts may be impossible. Here, we develop a theoretical framework for partitioning the effects of these processes. We show that when both mate and competitor recognition depend on the same trait, RCD sets the pace of character shifts. Moreover, RCD can cause divergence in competitor recognition, but ACD cannot cause divergence in mate recognition. This asymmetry arises because males with divergent recognition traits may avoid needless interspecific conflicts, but suffer reduced attractiveness to conspecific females. Therefore, the key empirical issue is whether the same or different traits are used for mate recognition and competitor recognition.     

无脊椎动物先天免疫模式识别受体研究进展

免疫系统的基本功能是“自己”与“非己”识别.对入侵物的识别是免疫防御的起始,最终引发效应物反应系统,包括吞噬作用、包被作用、激活蛋白酶级联反应和黑化作用以及诱导抗菌肽的合成等,从而清除或消灭入侵物.研究证明,这种“非己”识别是因为存在某些特异性的、可溶的或与细胞膜结合的模式识别受体,可以识别或结合微生物表面保守的、而在宿主中又不存在的病原相关分子模式.模式识别受体通过对病原相关分子的识别启动先天免疫防御.近年来这方面的研究进展很快,已经在无脊椎动物中确定了多种模式识别受体,包括肽聚糖识别蛋白、含硫酯键蛋白、革兰氏阴性菌结合蛋白、清除受体、C型凝集素、硫依赖型凝集素、Toll样受体和血素等,并对其性质和功能进行了研究.     

Pattern recognition proteins in Manduca sexta plasma

Recognition of nonself is the first step in mounting immune responses. In the innate immune systems of both vertebrates and arthropods, such recognition, termed pattern recognition, is mediated by a group of proteins, known as pattern recognition proteins or receptors. Different pattern recognition proteins recognize and bind to molecules (molecular patterns) present on the surface of microorganisms but absent from animals. These molecular patterns include microbial cell wall components such as bacterial lipopolysaccharide, lipoteichoic acid and peptidoglycan, and fungal beta-1,3-glucans. Binding of pattern recognition proteins to these molecular patterns triggers responses such as phagocytosis, nodule formation, encapsulation, activation of proteinase cascades, and synthesis of antimicrobial peptides. In this article, we describe four classes of pattern recognition proteins, hemolin, peptidoglycan recognition protein, beta-1,3-glucan recognition proteins, and immulectins (C-type lectins) involved in immune responses of the tobacco hornworm, Manduca sexta.     

Gamete and immune cell recognition revisited

Fertilization is the result of a series of successful recognition and binding events mediated by gamete surface molecules. Recent advances in the identification and characterization of some of these recognition molecules provide extremely valuable information necessary to understand sperm-egg recognition and subsequent egg activation. We discuss these new data in the context of the model of gamete recognition first proposed by F.R. Lillie in the early part of the 20th century, and revisited periodically in the subsequent literature, which relates fortilization events to those of immune cell recognition and activation events. Here we discuss the principles underlying the molecular recognition and activation mechanisms of gametes and immune cells.     

A review of automatic recognition technology for bird vocalizations in the deep learning era

Birds are considered critical indicators of ecosystem condition. Automatic recording devices have emerged as a trending tool to assist field observations, contributing to biodiversity monitoring on large spatio-temporal scales. However, manually processing huge volumes of recordings is challenging. Consequently, there has been a growing interest in automatic bird vocalization recognition in recent years. Automatic bird vocalization recognition technology has advanced from classical pattern recognition to deep learning (DL), with significantly improved recognition performance. This paper reviews related works on DL-based automatic bird vocalization recognition technology in the last decade. In this review, we present the current state of research in the three key areas of pre-processing, feature extraction and recognition methods involved in automatic bird vocalization recognition. The related datasets, evaluation metrics and software are also summarized. Finally, existing challenges along with opportunities for future work are highlighted. We conclude that, while DL-based automatic bird vocalization recognition has made recent advances in specific species, more robust denoising approaches, larger public datasets, and stronger generalization capabilities of feature extraction and recognition are required to achieve reliable and general bird recognition in the wild. We expect that this review will serve as a firm foundation for new researchers working in the field of DL-based automatic bird vocalization recognition technologies, as well as become an insightful guide for computer science and ecology experts.     

Uniform Local Binary Pattern Based Texture-Edge Feature for 3D Human Behavior Recognition

With the rapid development of 3D somatosensory technology, human behavior recognition has become an important research field. Human behavior feature analysis has evolved from traditional 2D features to 3D features. In order to improve the performance of human activity recognition, a human behavior recognition method is proposed, which is based on a hybrid texture-edge local pattern coding feature extraction and integration of RGB and depth videos information. The paper mainly focuses on background subtraction on RGB and depth video sequences of behaviors, extracting and integrating historical images of the behavior outlines, feature extraction and classification. The new method of 3D human behavior recognition has achieved the rapid and efficient recognition of behavior videos. A large number of experiments show that the proposed method has faster speed and higher recognition rate. The recognition method has good robustness for different environmental colors, lightings and other factors. Meanwhile, the feature of mixed texture-edge uniform local binary pattern can be used in most 3D behavior recognition.     

The aminoacylation of transfer ribonucleic acid. Recognition of methionine by Escherichia coli methionyl-transfer ribonucleic acid synthetase.

The mechanism of the recognition of methionine by Escherichia coli methionyl-tRNA synthetase was examined by a kinetic study of the recognition of methionine analogues in the ATP-PPi exchange reaction and the tRNA-aminoacylation reaction. The results show that the recognition mechanism consists of three parts: (1) the recognition of the size, shape and chemical nature of the amino acid side chain at the methionine-binding stage of the reaction; (2) the recognition of the length of the side chain at the stage of aminoacyl-adenylate complex-formation; (3) the recognition of the sulphur atom in the side chain at the stage of methionyl-tRNA formation. It is proposed that the sulphur atom interacts with the enzyme to induce a conformational change. A model of the active site incorporating the mechanism of methionine recognition is presented.     

The human EEG in recognition of noisy visual images accompanied by music

The recognition of noisy visual images (Arabic numerals) carried out under the conditions of recognition accompanied by classical or rock music of a specified power improves the recognition. When music-accompanied recognition of visual images is carried out, the structure of coherent relations (their number and significance level) observed during recognition without musical accompaniment is activated and the left-sided asymmetry of the coherence values is also retained (instead of the right-sided asymmetry, which appears in response to music alone). In other words, when the recognition dominant is formed at the behavioral level, changes in the spatial organization of the neocortical electrical processes also seem to follow the dominant principle.     

Graded Effects of Social Conformity on Recognition Memory

Previous studies have shown that the opinion of confederates in a group influences recognition memory, but inconsistent results have been obtained concerning the question of whether recognition of items as old and new are affected similarly, possibly because only one or two confederates are present during the recognition phase. Here, we present data from a study where recognition of novel faces was tested in the presence of four confederates. In a long version of this experiment, recognition of items as old and new was similarly affected by group responses. However, in the short version, recognition of old items depended proportionally on the number of correct group responses, while rejection of new items only decreased significantly when all confederates gave an incorrect response. These findings indicate that differential effects of social conformity on recognition of items as old and new occur in situations with an intermediate level of group pressure.     

Innate visual object recognition in vertebrates: some proposed pathways and mechanisms

Almost all vertebrates are capable of recognizing biologically relevant stimuli at or shortly after birth, and in some phylogenetically ancient species visual object recognition is exclusively innate. Extensive and detailed studies of the anuran visual system have resulted in the determination of the neural structures and pathways involved in innate prey and predator recognition in these species [Behav. Brain Sci. 10 (1987) 337; Comp. Biochem. Physiol. A 128 (2001) 417]. The structures involved include the optic tectum, pretectal nuclei and an area within the mesencephalic tegmentum. Here we investigate the structures and pathways involved in innate stimulus recognition in avian, rodent and primate species. We discuss innate stimulus preferences in maternal imprinting in chicks and argue that these preferences are due to innate visual recognition of conspecifics, entirely mediated by subtelencephalic structures. In rodent species, brainstem structures largely homologous to the components of the anuran subcortical visual system mediate innate visual object recognition. The primary components of the mammalian subcortical visual system are the superior colliculus, nucleus of the optic tract, anterior and posterior pretectal nuclei, nucleus of the posterior commissure, and an area within the mesopontine reticular formation that includes parts of the cuneiform, subcuneiform and pedunculopontine nuclei. We argue that in rodent species the innate sensory recognition systems function throughout ontogeny, acting in parallel with cortical sensory and recognition systems. In primates the structures involved in innate stimulus recognition are essentially the same as those in rodents, but overt innate recognition is only present in very early ontogeny, and after a transition period gives way to learned object recognition mediated by cortical structures. After the transition period, primate subcortical sensory systems still function to provide implicit innate stimulus recognition, and this recognition can still generate orienting, neuroendocrine and emotional responses to biologically relevant stimuli.     

Deficits in long-term recognition memory reveal dissociated subtypes in congenital prosopagnosia

The study investigates long-term recognition memory in congenital prosopagnosia (CP), a lifelong impairment in face identification that is present from birth. Previous investigations of processing deficits in CP have mostly relied on short-term recognition tests to estimate the scope and severity of individual deficits. We firstly report on a controlled test of long-term (one year) recognition memory for faces and objects conducted with a large group of participants with CP. Long-term recognition memory is significantly impaired in eight CP participants (CPs). In all but one case, this deficit was selective to faces and didn't extend to intra-class recognition of object stimuli. In a test of famous face recognition, long-term recognition deficits were less pronounced, even after accounting for differences in media consumption between controls and CPs. Secondly, we combined test results on long-term and short-term recognition of faces and objects, and found a large heterogeneity in severity and scope of individual deficits. Analysis of the observed heterogeneity revealed a dissociation of CP into subtypes with a homogeneous phenotypical profile. Thirdly, we found that among CPs self-assessment of real-life difficulties, based on a standardized questionnaire, and experimentally assessed face recognition deficits are strongly correlated. Our results demonstrate that controlled tests of long-term recognition memory are needed to fully assess face recognition deficits in CP. Based on controlled and comprehensive experimental testing, CP can be dissociated into subtypes with a homogeneous phenotypical profile. The CP subtypes identified align with those found in prosopagnosia caused by cortical lesions; they can be interpreted with respect to a hierarchical neural system for face perception.     

Neural mechanisms of object recognition

Single-unit recordings from behaving monkeys and human functional magnetic resonance imaging studies have continued to provide a host of experimental data on the properties and mechanisms of object recognition in cortex. Recent advances in object recognition, spanning issues regarding invariance, selectivity, representation and levels of recognition have allowed us to propose a putative model of object recognition in cortex.     

基于多特征融合的多分类运动想象脑电信号识别研究

针对目前多分类运动想象脑电识别存在特征提取单一、分类准确率低等问题,提出一种多特征融合的四分类运动想象脑电识别方法来提高识别率。对预处理后的脑电信号分别使用希尔伯特-黄变换、一对多共空间模式、近似熵、模糊熵、样本熵提取结合时频—空域—非线性动力学的初始特征向量,用主成分分析降维,最后使用粒子群优化支持向量机分类。该算法通过对国际标准数据集BCI2005 Data set IIIa中的k3b受试者数据经MATLAB仿真处理后获得93.30%的识别率,均高于单一特征和其它组合特征下的识别率。分别对四名实验者实验采集运动想象脑电数据,使用本研究提出的方法处理获得了72.96%的平均识别率。结果表明多特征融合的特征提取方法能更好的表征运动想象脑电信号,使用粒子群支持向量机可取得较高的识别准确率,为人脑的认知活动提供了一种新的识别方法。     

Differential Transit Peptide Recognition during Preprotein Binding and Translocation into Flowering Plant Plastids

Despite the availability of thousands of transit peptide (TP) primary sequences, the structural and/or physicochemical properties that determine TP recognition by components of the chloroplast translocon are not well understood. By combining a series of in vitro and in vivo experiments, we reveal that TP recognition is determined by sequence-independent interactions and vectorial-specific recognition domains. Using both native and reversed TPs for two well-studied precursors, small subunit of ribulose-1,5-bis-phosphate carboxylase/oxygenase, and ferredoxin, we exposed these two modes of recognition. Toc34 receptor (34-kD subunit of the translocon of the outer envelope) recognition in vitro, preprotein binding in organellar, precursor binding in vivo, and the recognition of TPs by the major stromal molecular motor Hsp70 are specific for the physicochemical properties of the TP. However, translocation in organellar and in vivo demonstrates strong specificity to recognition domain organization. This organization specificity correlates with the N-terminal placement of a strong Hsp70 recognition element. These results are discussed in light of how individual translocon components sequentially interact with the precursor during binding and translocation and helps explain the apparent lack of sequence conservation in chloroplast TPs.