Deficient pheromone responses in mice lacking a cluster of vomeronasal receptor genes

The mammalian vomeronasal organ (VNO), a part of the olfactory system, detects pheromones--chemical signals that modulate social and reproductive behaviours. But the molecular receptors in the VNO that detect these chemosensory stimuli remain undefined. Candidate pheromone receptors are encoded by two distinct and complex superfamilies of genes, V1r and V2r (refs 3 and 4), which code for receptors with seven transmembrane domains. These genes are selectively expressed in sensory neurons of the VNO. However, there is at present no functional evidence for a role of these genes in pheromone responses. Here, using chromosome engineering technology, we delete in the germ line of mice an approximately 600-kilobase genomic region that contains a cluster of 16 intact V1r genes. These genes comprise two of the 12 described V1r gene families, and represent approximately 12% of the V1r repertoire. The mutant mice display deficits in a subset of VNO-dependent behaviours: the expression of male sexual behaviour and maternal aggression is substantially altered. Electrophysiologically, the epithelium of the VNO of such mice does not respond detectably to specific pheromonal ligands. The behavioural impairment and chemosensory deficit support a role of V1r receptors as pheromone receptors.     

Sex-specific peptides from exocrine glands stimulate mouse vomeronasal sensory neurons

In mammals, social and reproductive behaviours are modulated by pheromones, which are chemical signals that convey information about sex and strain. The vomeronasal organ, located at the base of the nasal septum, is responsible for mediating pheromone information in mice. Two classes of putative pheromone receptor gene families, V1R and V2R, are expressed by vomeronasal sensory neurons in mutually segregated epithelial zones of the vomeronasal organ. Although numerous studies have suggested that pheromones originate from urine, direct recordings of behaving mice have shown that neuronal firing in the vomeronasal system is modulated by physical contact with the facial area. Here we identify a male-specific 7-kDa peptide secreted from the extraorbital lacrimal gland. This peptide, which we named exocrine gland-secreting peptide 1 (ESP1), is encoded by a gene from a previously unrecognized large family clustered in proximity to the class I major histocompatibility complex (MHC) region. ESP1 is secreted from the eyes and is transferred to the female vomeronasal organ, where it stimulates V2R-expressing vomeronasal sensory neurons and elicits an electrical response. Our results indicate that mice respond to sex-specific peptides released from exocrine glands through the vomeronasal system during direct contact.     

基于超顶点交流策略的并行蚁群算法

通过分析影响并行蚁群算法性能的诸多因素,以提高算法效率减少通信量为主旨,提出了1种基于超顶点交流策略的并行蚁群算法.在该算法中,处理机之间交流的内容不再是最优解或信息素矩阵,而是由若干个顶点组合成的超顶点,从而改变了计算粒度;其次,又提出了1种更忠实于真实蚁群信息系统的基于信息素递减的信息素更新方法,减少了最优解对蚂蚁后选择路径上信息素的影响.通过对TSP进行的实验表明,与其他交流策略的并行蚁群算法相比,该算法有较强的全局收敛性和更快的寻优速度.     

基于超顶点交流策略的并行蚁群算法

通过分析影响并行蚁群算法性能的诸多因素，以提高算法效率减少通信量为主旨，提出了1种基于超顶点交流策略的并行蚁群算法．在该算法中，处理机之间交流的内容不再是最优解或信息素矩阵，而是由若干个顶点组合成的超顶点，从而改变了计算粒度；其次，又提出了1种更忠实于真实蚁群信息系统的基于信息素递减的信息素更新方法，减少了最优解对蚂蚁后选择路径上信息素的影响．通过对TSP进行的实验表明，与其他交流策略的并行蚁群算法相比，该算法有较强的全局收敛性和更快的寻优速度．     

Advances in research of mammalian vomeronasal pheromone perception and genetic components unique to vomeronasal signal transduction pathway

The recognition and perception of chemical signals from environments are very important for the survival of organisms. In mammals, general chemical signals are mainly detected by the main olfactory system (MOS), while pheromones are primarily perceived by the vomeronasal system (VNS). Pheromones are chemicals released and recognized by individuals within the same species, which then induce physiological and behavioral changes in social and sexual activities. In this review, we focus on the recent advances on research in mammalian vomeronasal pheromone perception and those genetic components unique to vomeronasal signal transduction pathway, including vomeronasal receptor V1R and V2R gene families as well as transient receptor potential channel 2 gene (TRPC2), trying to shed light on further study of the molecular mechanisms of mammalian pheromone perception.     

基于信息素改进的蚁群算法

蚁群算法是一种优秀的启发式算法,具有较强的鲁棒性。针对基本蚁群算法在求解过程中容易出现收敛时间过长以及容易陷入局部最优的不足。本文提出了一种改进的蚁群算法,该算法通过在信息素挥发系数上增加一个收敛函数,加快了收敛速度;通过信息素增量与优秀路径选择相结合,引导算法收敛到最优路径,实验结果表明,改进后的算法在收敛速度和全局寻优能力上有了较大的提高。     

Identification of protein pheromones that promote aggressive behaviour

Mice use pheromones, compounds emitted and detected by members of the same species, as cues to regulate social behaviours such as pup suckling, aggression and mating. Neurons that detect pheromones are thought to reside in at least two separate organs within the nasal cavity: the vomeronasal organ (VNO) and the main olfactory epithelium (MOE). Each pheromone ligand is thought to activate a dedicated subset of these sensory neurons. However, the nature of the pheromone cues and the identity of the responding neurons that regulate specific social behaviours are largely unknown. Here we show, by direct activation of sensory neurons and analysis of behaviour, that at least two chemically distinct ligands are sufficient to promote male-male aggression and stimulate VNO neurons. We have purified and analysed one of these classes of ligand and found its specific aggression-promoting activity to be dependent on the presence of the protein component of the major urinary protein (MUP) complex, which is known to comprise specialized lipocalin proteins bound to small organic molecules. Using calcium imaging of dissociated vomeronasal neurons (VNs), we have determined that the MUP protein activates a sensory neuron subfamily characterized by the expression of the G-protein Galpha(o) subunit (also known as Gnao) and Vmn2r putative pheromone receptors (V2Rs). Genomic analysis indicates species-specific co-expansions of MUPs and V2Rs, as would be expected among pheromone-signalling components. Finally, we show that the aggressive behaviour induced by the MUPs occurs exclusively through VNO neuronal circuits. Our results substantiate the idea of MUP proteins as pheromone ligands that mediate male-male aggression through the accessory olfactory neural pathway.     

Genomic organization and sequence analysis of the vomeronasal receptor V2R genes in mouse genome

Two multigene superfamilies, named V1R and V2R, encoding seven-transmembrane-domain G-protein coupled receptors (GPCRs) have been identified as pheromone receptors in mammals. Three V2R gene families have been described in mouse and rat. Here we screened the updated mouse genome se- quence database and finally retrieved 63 putative functional V2R genes including three newly identified genes which formed a new additional family. We described the genomic organization of these genes and also characterized the conservation of mouse V2R protein sequences. These genomic and se- quence information we described are useful as part of the evidence to speculate the functional domain of V2Rs and should give aid to the functionality study in the future.     

基于动态参数蚁群算法的寻源导热反问题研究

基于蚁群优化算法,求解含有未知内热源位置的导热逆问题.通过分析计算表明:信息素启发因子、能见度启发因子、信息素挥发率等蚁群参数对蚁群选择路径以及路径上信息素浓度更新有直接影响,其取值最终会影响求解结果的准确性及收敛速度.在计算过程中,路径上的信息素浓度不断改变,蚂蚁选择路径也趋于集中,采用定值蚁群参数不能满足在整个计算过程中都具有良好的性能,为此提出了动态参数蚁群算法,并根据计算分析结果确定蚁群参数值随全局循环次数而变的动态函数.计算结果证明,采用动态参数蚁群算法能有效提高求解反问题的质量及收敛速度.     

一种基于监工机制的改进蚁群算法

针对基本蚁群算法存在收敛速度慢、易陷入局部最优解等问题,受监工机制的启发,提出了监工蚁群算法,以监工距离作为评价标准,自适应地选择优良的蚂蚁更新信息素,提高了每次迭代中解的质量,指导之后的蚂蚁进行更好的学习。该算法选用优化的全局更新策略,使得信息素在进化前期增加较多,在后期增加较少;同时,自适应地将信息素的值限定在一定范围内,防止某条路径被选择的概率过大或者过小。该算法还添加了发散和收敛机制,当算法陷入局部最优解时,增加探索的概率,有助于跳出局部最优解。仿真结果表明,监工蚁群算法具有较高的全局寻优能力,减少了迭代次数,增强了算法的稳定性。     

大袋蛾性信息素研究初报

<正>大袋蛾不但具有独特的生活习性,而且雌虫性信息素的分泌部位和化学结构亦不同于一般鳞翅目蛾类。我们的初步工作证实,大袋蛾雌成虫的性引诱能力极强,其性信息素的分泌部位主要在胸部背板区。用漂洗法提取,可消除屏蔽物质的干扰和减少杂质的污染。大袋蛾性信息素的化学结构不同于一般鳞翅目蛾类的不饱和长碳链醇、乙酸酯或醛、酮之类。其主要活性组分的分子量为270,分子式C_(17)H_(34)O_2。此外,还有多元组分存在的可能性。结构鉴定的进一步工作正在进行。     

Synthesis and Properties of Novel Copolymers Based on Fluorene and Thiophene

1 Results In this contribution we present the synthesis and characterization of novel copolymers based on fluorene and thiophene (see Scheme 1).They were synthesized by the Pd-catalyzed Suzuki coupling reaction of 9,9-dihexylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester and 3-substituted (R=3-methylbutyl,hexyl,2-(pyren-1-yl)vinyl) 2,5-dibromothiophenes and characterized by GPC,IR and NMR techniques.UV-vis absorption,photoluminescence (PL) and electrochemical behavior of these polymers were also...     

红缘天牛对不同诱剂的EAG与行为反应及野外诱集效果

采用目前广泛应用的植物挥发性物质和性息素配制成25种引诱剂，对红缘天牛进行了行为、电生理测定及野外诱集实验．结果显示：诱剂W的诱集效果最好，相对诱捕率达21．8％，EAG值为4．116，亦最高．其次为诱剂T，相对诱捕率为17．2％，EAG值为3．714．诱剂X和V的相对诱捕率也较高，分别为9．2％和8．0％．另外，以青霉素注射剂药瓶作为诱芯的载体、以植物挥发性物质和性信息素作为诱剂研制而成的诱芯，缓释作用很好，具有应用推广价值．     

云杉红翅小蠹信息素Seudenone和(±)-Seudenol的简便合成

3-甲基环己-2-烯-1-酮(Seudenone)是云杉红翅小蠹的抑制信息素,3-甲基环己-2-烯-1-醇(±-Seudenol)却是一种聚集信息素.本合成利用乙酰乙酸乙酯和多聚甲醛为原料,通过缩合、水解脱羧和区域选择性还原三步反应合成了两个所需产物.     

团簇V3BP电子自旋密度的研究

基于密度泛函理论，对B3LYP/Lanl2dz赝势基组水平的V₃BP的11种优化构型通过分析其电子自旋密度分布进行稳定性的研究。结果表明：团簇V₃BP最稳定构型1^（4）外围电子自旋密度分布均匀，对称性好；内部原子间成键强弱均匀，对称性好；最不稳定构型8^（2）外围α电子和β电子交替分布且分布不均匀，对称性差且极不规整；内部原子间成键强度各不相同，同一类型键原子间成键强弱也不均匀；团簇V₃BP各优化构型的外围电子分布由α电子和β电子共同组成，且α电子所占比例较大；构型2^（4）、1^（2）、4^（2）、8^（2）内部原子间成键后均为β电子过剩，其余构型内部原子间成键后均为α电子过剩。     

硬蜱性信息素的研究

用气相色谱、X-射线微区分析、生物测定及电生理等方法,研究了硬蜱性信息素的成分、含量与吸血和交配的关系以及雄虫对性信息素的反应.硬蜱性信息素的主要成分为2,6-二氯酚.雌虫吸血后性信息素量明显增加,第3～5天达到高峰,交配后下降.雄虫哈氏器是感受性信息素的器官,其前窝感毛对2,6-二氯酚反应最灵敏,吸血7d时反应最强.     

CCN中一种非混合式蚁群路由优化策略

蚁群优化(ant colony optimization,ACO)近年来在信息中心网络(content centric networking,CCN)路由领域的应用逐渐增多,其中,将ACO与其他机制相混合以改善路由性能的策略得到较多研究,但基于蚁群优化的混合式算法通常存在可扩展性低下,动态性差,网络成本高等问题。为此提出一种高效的非混合式蚁群路由算法(irritant ant framework,IAF)。添加一个新维度—一种动态的、仿生物的信息素分层,将传统单级别信息素上升为多级别信息素,增强蚁群对于路径的探索程度,抑制算法过早收敛;并且考虑了节点状态的动态性,实时改变信息素等级以选择最佳转发路径;此外,首次考虑了节点缓存特性对信息素更新策略的影响,构造出全新的信息素更新公式,,减小算法的收敛时间。实验结果表明,该算法能够有效地降低内容请求时延,提升缓存命中率,以较低的开销获得良好的CCN路由性能。     

Cloning,expression and binding specificity analysis of odorant binding protein 3 of the lucerne plant bug, <Emphasis Type="Italic">Adelphocoris lineolatus</Emphasis> (Goeze)

Credible evidence shows that odorant binding proteins (OBPs) are required for insect olfaction perception and play a key role in transporting hydrophobic odorants across the sensillum lymph to the olfactory receptors (ORs). In the present study, a novel OBP (AlinOBP3) gene from the lucerne plant bug, Adelphocoris lineolatus, was cloned and expressed. The expression pattern of AlinOBP3 was evaluated by qPCR, which indicated that AlinOBP3 was dominantly expressed in antennae. The binding properties of AlinOBP3 with 9 cotton volatiles and 5 sex pheromone analogs were measured by fluorescence competitive binding assays with the fluorescence probe 1-NPN. The results revealed that of 9 cotton volatiles, Myrcene, β-Ocimene and α-Phellandrene can bind with AlinOBP3. α-Phellandrene especially bound to AlinOBP3 with a high binding affinity, with a dissociation constant of 56.68 μmol/L. Of the 5 sex pheromone analogs, Hexyl butyrate had the strongest binding affinity with AlinOBP3, with a dissociation constant as 59.53 μmol/L. Butyl butyrate, trans-2-Hexenyl butyrate and Ethyl butyrate had medium binding affinities with AlinOBP3, with dissociation constants of 227.39, 108.77 and 143.47 μmol/L, respectively. The results suggest that AlinOBP3 might be a pheromone binding protein (PBP) with a dual-function for the perception of sex pheromones and plant volatiles.     

基于二次退火机制的改进多态蚁群算法

利用多态蚁群算法和模拟退火算法的优点提出一种新的融合优化算法。研究结果表明:模拟退火用于优化每轮迭代后的路径,使得信息素释放更好的反映路径的质量;退火思想同时用于信息素更新机制,避免算法早熟、停滞,较差的路径按照退火竞争机制释放信息素;由于每轮迭代最优路径释放信息素最多,对其进行3-opt优化,提高搜索效率。同时,新发现的最优路径允许释放更多的信息素,使得蚂蚁在后续迭代中能够记住这条新路径。实验结果验证了算法的有效性。