Field response of Ips paraconfusus,Dendroctonus brevicomis,and their predators to 2-methyl-3-buten-2-ol,a novel alcohol emitted by ponderosa pine

Methylbutenol (MBO) is a major component of the aggregation pheromone of the European spruce beetle Ips typographus and also has been found to be emitted in large amounts by several species of pine native to western North America. This study investigates the influence this signal may have on the behavior of North American bark beetles and examines whether MBO functions as a defensive compound for emitting pines. The response of two North American bark beetles (Ips paraconfusus and Dendroctonus brevicomis) and their predaceous beetles (Trogositidae and Cleridae) to MBO, pheromone, and monoterpenes in varying release rates was investigated in the field using Lindgren funnel traps. MBO exhibited no repellent properties when tested alone, nor did MBO appear to have any effect on the aggregation response of these bark beetles and their predators to their pheromones. These results provide no support for a defensive function of MBO.     

Benzoic Acid Derivatives in a Hypogastrurid Collembolan: Temperature-Dependent Formation and Biological Significance as Deterrents

Two phenolic acids were identified in the collembolan Ceratophysella denticulata: 3-hydroxy-4,5 dimethoxy benzoic acid and 4-hydroxy-3,5-dimethoxybenzoic acid (syringic acid). These are localized on or in the integument of the springtail, in field-collected animals, in a ratio of 47:100 (v/v). Springtails kept under different temperature regimes showed differences in production and ratio of the benzoic acid derivatives. At 20 degrees C, C. denticulata produced only syringic acid, whereas at 10 degrees C both isomers in a ratio of 100:61 (v/v) were detected. Bioassays with C. denticulata as well as with the specialized collembolan predator Stenus comma (Staphylinidae) were carried out. Staphylinid beetles topically treated with the acids try to clean their mouthparts by rubbing them on the ground significantly more often than do control beetles. Both compounds individually and as a natural mixture have deterrent effects towards the predator S. comma.     

Predator odor-induced conditioned fear involves the basolateral and medial amygdala.

The basolateral (BLA) and medial nucleus (MeA) of the amygdala participate in the modulation of unconditioned fear induced by predator odor. However, the specific role of these amygdalar nuclei in predator odor-induced fear memory is not known. Therefore, fiber-sparing lesions or temporary inactivation of the BLA or MeA were made either prior to or after exposure to cat odor, and conditioned contextual fear behavior was examined the next day. BLA and MeA lesions produced significant reductions in cat odor-induced unconditioned and conditioned fear-related behavior. In addition, temporary pharmacological neural inactivation methods occurring after exposure to cat odor revealed subtle behavioral alterations indicative of a role of the BLA in fear memory consolidation but not memory retrieval. In contrast, the MeA appears to play a specific role in retrieval but not consolidation. Results show that the BLA participates in the conditioned and unconditioned cat odor stimulus association that underlies fear memory, underscore a novel role of the MeA in predator odor contextual conditioning, and demonstrate different roles of the BLA and MeA in modulating consolidation and retrieval of predator odor fear memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Defensive behavior and hippocampal cell proliferation: Differential modulation by naltrexone during stress.

The present study investigated the role of endogenous opioids in the expression of defensive behaviors (DBs) and the suppression of cell proliferation (CP) in the dentate gyrus (DG) induced by exposure to predator odor, trimethyl thiazoline (TMT). Adult male rats were injected with either naltrexone (an opioid antagonist, 5 mg/kg) or saline 30 min before exposure to either TMT or a control odor. Behavior was scored for the first 15 min of odor exposure. Bromodeoxyuridine (BrdU, 200 mg/kg) was then injected, and the rats were perfused 1 hr later. Exposure to TMT increased the expression of DBs and suppressed the number of proliferating cells in the DG. Pretreatment with naltrexone attenuated the effects of TMT on DB expression but did not attenuate the effects of TMT on CP. In addition, naltrexone administration suppressed CP in the absence of TMT. These results demonstrate a dissociation between DBs and regulation of CP in the DG. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于化学计量学分析堆青时间对白茶香气的影响

堆青是一种有利于茶叶香气转化的手段,本文研究了堆青时间对白茶香气的影响,并分析了感官香气与化合物变化间的联系。感官审评结果表明,堆青使白茶甜香增强而鲜度下降。通过顶空固相微萃取和气相色谱-串联质谱联仪从样品中表征出55种化合物,它们的组成受堆青影响甚微,但含量变化显著。基于化学计量学方法筛选并分析37种差异化合物;主成分分析和层次聚类分析均可区分不同堆青处理的样品,其中堆青前后样品间差异明显。苯乙醇、苯甲醛和苯乙醛等随堆青的总体上升,以及β-环柠檬醛、反-2-辛烯醛和α-紫罗兰酮在堆青后含量的普遍增加,可能是引起甜香增强的原因。而正己醇、反,反-2,4-己二烯醛和辛醛在堆青后含量的普遍减少,则可能与鲜度下降相关。32 h的堆青较有利于白茶香气的发展。化学计量学方法的引入使得样品间差异信息的获取更有效率。     

Olfactory Responses to Aphid and Host Plant Volatile Releases: (E)-β-Farnesene an Effective Kairomone for the Predator Adalia bipunctata

The volatiles released from several aphid and host plant species, alone or associated, were studied for their infochemical role in prey location. Using a four-arm olfactometer, the attraction of several combinations of three aphid (Myzus persicae, Acyrthosiphon pisum, and Brevicoryne brassicae) and three plant (Vicia faba, Brassica napus, and Sinapis alba) species toward Adalia bipunctata larvae and adults was observed. Both predatory larvae and adults were attracted only by A. pisum and M. persicae when they were crushed, whatever the host plant. (E)-beta-farnesene, the aphid alarm pheromone, was the effective kairomone for the ladybird. Plant leaves alone (V. faba, B. napus, and S. alba) or in association with nonstressed whole aphids (the three species) did not have any attraction for the predator. The B. brassicae specialist aphid is the only prey that was not attracted to A. bipunctata larvae and adults, even if they were crushed. Release of B. brassicae molecules similar to the host plant allelochemicals was demonstrated by GC-MS analysis. The lack of behavioral response of the ladybird at short distance toward the cruciferous specialist aphid was related only to the absence of (E)-beta-farnesene in the aphid prey volatile pattern.     

Engineered Bdellovibrio bacteriovorus: A countermeasure for biofilm-induced periodontitis

Periodontitis is caused by subgingival plaque biofilm mainly composed of Gram-negative bacteria, affecting human populations at a high prevalence. Antibiotics therapy is the traditional method for periodontitis, but its efficiency in removing plaque biofilm is limited. With the aim to find an effective therapeutic method to treat periodontitis, we reported a material-assistant micro-organism (MAMO) strategy to eradicate Gram-negative bacteria biofilm using ZnO nanorods engineered Bdellovibrio (ZnO@Bdello). Bdellovibrio bacteriovorus is a natural Gram-negative bacteria predator with strong motility. ZnO nanorods are a kind of common piezoelectric material that senses mechanical pressure and produces reactive oxygen species (ROS). During the predation process of Bdellovibrio, the collision of Bdellovibrio triggered ZnO nanorods to produce ROS to enhance the removal of plaque biofilm. Both in vitro and in vivo studies showed ZnO@Bdello could remove biofilm effectively. In addition, ZnO@Bdello possessed superior competence in alleviating inflammation and inhibiting bone resorption in rats and rabbit periodontitis models. Importantly, this strategy does not induce detectable pathogen resistance and side effects.     

From sustainability to sustainizability

Following the recent introduction of the Sustainability over Sets (SOS) concept as a sustainability analysis tool with broad flexibility in incorporating human input, in this work, the concepts of Sustainizability (SIZ) and Sustainizability over Sets (SIZOS) are introduced, as novel frameworks for sustainable system synthesis. Springing off the conceptual foundation of sustainability, SIZ (and SIZOS) refers to the existence of allowable external actions, and/or design changes that can render sustainable (sustainable over a set) an unsustainable (unsustainable over a set) system. Utilizing earlier mathematical results for SOS, rigorous necessary and sufficient conditions for SIZOS are presented. Two case studies, on a two-dimensional biological waste treatment system, and a three-dimensional food chain system, are then presented to illustrate the developed necessary and sufficient conditions for SIZOS.     

具有捕食者Allee效应的Leslie - Gower模型的动力学分析

研究了在Leslie - Gower模型中加入捕食者Allee效应后的模型动力学行为变化.研究表明:加入捕食者Allee效应后,模型的所有正解是一致有界的,唯一的正平衡点是全局渐近稳定的,但两个边界平衡点是不稳定的.Allee效应虽然不会改变正平衡点的稳定性,但其延长了正平衡点趋向稳定状态的时间,同时也改变了原点的性态,即Allee效应不利于系统的稳定性.     

Behavioral Changes Induced in Rats by Exposure to Trimethylthiazoline, a Component of Fox Odor.

Trimethylthiazoline (TMT), a component of fox feces, has been used in various studies as a natural predator stimulus to induce autonomic and behavioral signs of fear (e.g., higher levels of stress hormones, freezing, and risk assessment). The present study investigated whether 2 further behavioral signs of fear are induced in rats by TMT exposure: potentiation of the acoustic startle response and inhibition of appetitive behavior. In addition, the authors tested the rats for dose dependency of TMT-induced freezing behavior. The study confirmed that behavioral changes observed during TMT exposure are caused by TMT-induced fear and are dose dependent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)