<Emphasis Type="Italic">Alona alsafadii</Emphasis> n. sp. from Yemen,a primitive,groundwater-dwelling member of the <Emphasis Type="Italic">A. karua</Emphasis>-group

The effect of algae on the production of musty-smelling compounds by actinomycetes was studied. Streptomyces spp., causing intensive musty odor, were isolated from hypertrophic Lake Kasumigaura and cultured in association with algae from the same lake. Isolate E and I effectively utilized the cyanobacteria, Microcystis aeruginosa and Anabaena spiroides, and the diatom, Synedra acus, as a carbon source and produced a musty-smelling 2-methylisoborneol in the shaken sediment cultures. High populations of algae and actinomycetes, and aerobic condition in the sediment seem responsible for the occurrence of musty odor in Lake Kasumigaura.     

Behavioral responses to odorants in drosophila require nervous system expression of the beta integrin gene myospheroid

Integrins are cell adhesion molecules that mediate numerous developmental processes in addition to a variety of acute physiological events. Two reports implicate a Drosophila beta integrin, betaPS, in olfactory behavior. To further investigate the role of integrins in Drosophila olfaction, we used Gal4-driven expression of RNA interference (RNAi) transgenes to knock down expression of myospheroid (mys), the gene that encodes betaPS. Expression of mys-RNAi transgenes in the wing reduced betaPS immunostaining and produced morphological defects associated with loss-of-function mutations in mys, demonstrating that this strategy knocked down mys function. Expression of mys-RNAi transgenes in the antennae, antennal lobes, and mushroom bodies via two Gal4 lines, H24 and MT14, disrupted olfactory behavior but did not alter locomotor abilities or central nervous system structure. Olfactory behavior was normal in flies that expressed mys-RNAi transgenes via other Gal4 lines that specifically targeted the antennae, the projection neurons, the mushroom bodies, bitter and sweet gustatory neurons, or Pox neuro neurons. Our studies confirm that mys is important for the development or function of the Drosophila olfactory system. Additionally, our studies demonstrate that mys is required for normal behavioral responses to both aversive and attractive odorants. Our results are consistent with a model in which betaPS mediates events within the antennal lobes that influence odorant sensitivity.     

The influence of training on chemosensory event-related potentials and interactions between the olfactory and trigeminal systems

It is not possible to accurately predict the perceptual response to odorants and odorant mixtures without understanding patterns of suppression and facilitation that result from interactions between the olfactory and trigeminal systems. The current study extends previous findings by exploring the effect of intensive training on the interaction between these systems and also by using a different mixed chemosensory stimulus to examine whether the principles established in earlier studies generalize to different odorants. Stimuli were chosen so as to selectively activate the olfactory (H2S) and trigeminal (CO2) nerves. In addition, linalool was included as a stimulus that activated both systems. Thirty-five participants (19 men, 16 women) rated the intensity of each stimulus when presented both alone and in binary mixtures (linalool + H2S, and linalool + CO2). Chemosensory event-related potentials were obtained from three recording positions. Analysis of intensity ratings showed that linalool was significantly less intense than the other stimuli when presented alone. In binary mixtures, H2S was strongly suppressed by linalool. One week of intensive odor training produced significant and specific reductions in the intensity of linalool and H2S, both alone and in their mixture. Training with a different odor (champignol) had no effect. Chemosensory event-related potential data confirmed previous findings showing changes in topographical distribution that reflected the degree of trigeminal activity. Binary mixtures generally produced larger amplitudes than single stimuli. Latencies clearly differentiated between the three single stimuli and the binary mixtures. Changes were observed in event-related potentials that reflected those obtained for intensity ratings in that they were observed for linalool and H2S in the linalool trained group only. The amplitude of the late 'endogenous' component (P3) was significantly decreased for these odors at frontal recording sites. In summary, strong and specific training effects were observed in intensity ratings for participants trained with the test odor (linalool), but not for those trained with a different odor. This was supported by a significant decrease of amplitudes of the event-related potentials at frontal recording sites following training with the test odor only     

甘蔗、玉米气味对亚洲玉米螟成虫产卵和幼虫取食的影响

【目的】农作物间套作对害虫的影响很大程度上取决于害虫的行为反应,通过研究玉米/甘蔗套作系统中植物气味对亚洲玉米螟Ostrinia furnacalis(Guenee)行为的影响,将为利用化学生态手段防治套作田中的害虫提供依据。【方法】通过昆虫触角电位实验、成虫产卵和幼虫取食实验,测定了甘蔗、玉米植株及二氯甲烷漂洗物对亚洲玉米螟成虫产卵、幼虫取食的影响。【结果】亚洲玉米螟成虫在甘蔗植株上的落卵量(卵粒数、卵块数)与玉米植株差异不显著,取食甘蔗植株的幼虫数量显著低于玉米植株。亚洲玉米螟对甘蔗、玉米叶片漂洗物均可产生EAG反应,且在同一浓度下的反应值之间无显著差异。成虫产卵量(卵粒数、卵块数)在0.1 gE/mL浓度的甘蔗和玉米漂洗物间差异不显著;幼虫对经甘蔗叶片漂洗物处理过的饲料的相对取食率均低于65.00%,显著低于玉米漂洗物处理的饲料。【结论】甘蔗和玉米气味对亚洲玉米螟产卵的影响没有差异,但甘蔗气味会导致初孵幼虫表现出很强的逃逸行为。     

Fear-like behavioral responses in mice in different odorant environments: Trigeminal versus olfactory mediation under low doses

Odors can have repulsive effects on rodents based on two complementary adaptive behaviors: the avoidance of predator odors (potentially dangerous) and the avoidance of trigeminal stimulants (potentially noxious). The present study aimed to compare the behavioral effects on mice of odors according to their trigeminal properties and ecological significance. We used three different odors: 2,4,5-trimethylthiazoline (TMT: a fox feces odor frequently used to elicit fear-induced behaviors), toluene (a strong stimulant of the trigeminal system) and phenyl ethyl alcohol (PEA: a selective stimulant of the olfactory system). First, we checked preference and avoidance behaviors in mice with and without anosmia towards these odors to ensure their olfactory/trigeminal properties. Secondly, we used a standard test (open-field and elevated plus-maze) to assess the behaviors of mice when exposed to these odors. The results show that the anosmic and control mice both avoided TMT and toluene odors. In the open-field and the elevated plus-maze, mice exhibited "anxious" behaviors when exposed to TMT. Conversely, exposure to PEA induced "anxiolytic" effects confirmed by low blood corticosterone levels resulting from completion of the elevated plus-maze. Compared with TMT exposure, toluene exposure induced moderate "anxious" effects.     

狭叶坡垒传粉生物学初探

狭叶坡垒(Hopea chinensis)为常绿乔木,是我国热带季雨林的代表树种之一。它树型优美,具一定的耐寒性,是我国珍稀濒危保护植物。为阐明其传粉生物学特征和迁地保护的繁殖潜力,该文在引种地桂林植物园对狭叶坡垒的开花物候、花尺寸和花气味进行了观察和测量,运用杂交指数(OCI)、花粉胚珠比(P/O)、花粉活力、柱头活性检测和人工自交等方法对其繁育系统进行了检测,观察了访花昆虫并检验了其传粉效率,通过人工异交检验了繁殖潜力和可能的传粉限制。结果表明:(1)桂林植物园内狭叶坡垒的花期为7月底到9月底,持续60 d左右,一个花序花期约12 d,单花期约3 d,花朵开放时间为17:00—18:45。(2)雌雄同熟,雌蕊空间位置高于雄蕊,高花粉活力和高柱头可授性出现时间基本一致。(3) OCI等于4,P/O为10 788±984。(4)无自动自花授粉能力且自交不亲和,自然条件下和异交授粉能坐果且坐果率无显著差异。(5)蕈蚊是狭叶坡垒唯一的传粉者。(6)主要花香成分为β-榄香烯、(E)-7,11-二甲基-3-亚甲基-1,6,10-十二碳三烯和1-石竹烯。综上所述,狭叶坡垒繁育系统为异交,在迁地保...     

Evaluating Human Risk from Exposure to Alkylated PAHs in an Aquatic System

Polycyclic aromatic hydrocarbons (PAHs) are a large class of organic chemicals typically found as mixtures in the aquatic environment from natural, petrogenic, and pyrogenic sources. People can be exposed to PAHs through ingestion or dermal contact with contaminated sediments or through ingestion of finfish and shellfish exposed to contaminated sediments. Although more than 100 PAHs have been identified, human exposure and risk are commonly evaluated for 18 individual PAHs. Other PAHs, such as alkylated PAHs, likely contribute to biological activity of environmental PAH mixtures; however, insufficient toxicity data are available to quantify their potential risk. This article presents an initial evaluation of the potential for human health risk from exposure to alkylated PAHs in sediment and fish. Individual alkylated PAHs have been observed to have potentially mutagenic, tumor-promoting, or carcinogenic activity. However, except for 1-and 2-methylnaphthalene, insufficient toxicity data are available to quantify toxicity or cancer risk from exposure to individual alkylated PAHs or mixtures of alkylated PAHs. This article describes a proposed strategy to better understand the potential human health risk from exposure to alkylated PAHs. Implementation of this strategy will contribute to evaluations of human exposure to complex PAH mixtures in the environment.     

The interactive effects of elevated CO<Subscript>2</Subscript>, temperature and initial size on growth and competition between a native C<Subscript>3</Subscript> and an invasive C<Subscript>3</Subscript> grass

A controlled environment experiment was conducted to determine the impact of enhanced carbon dioxide and temperature on competition between the C₃ grasses Austrodanthonia eriantha and Vulpia myuros. Plants were grown in mixtures and monocultures to compare the responses both with and without an interspecific competitor. Temperature and CO₂ were set at current levels (350 ppm CO₂; 20 °C day and 10 °C night temperature), in factorial combination with enhanced levels (700 ppm CO₂; 23 °C day and 13 °C night temperature). To examine the potential impact of initial seedling size on competition under elevated CO₂ and temperature, the two species were combined in mixtures of differing initial sizes. Above-ground growth of all plants was enhanced by increased CO₂ and temperature alone, however the combined temperature and CO₂ treatment showed a sub-additive effect, where growth was less than expected based on the responses to each factor independently. Austrodanthonia in mixture with Vulpia plants of the same initial size experienced a 27 reduction in growth. Austrodanthonia grown in the presence of an initially larger Vulpia plant experienced a 58 reduction in growth. When the Vulpia plant was initially smaller than Austrodanthonia, growth of the Austrodanthonia was reduced by 16%. The growth of Vulpia appeared to be largely unaffected by the presence of Austrodanthonia. Variation in the CO₂ and temperature environment did not affect the pattern of these interspecific interactions, although there was some evidence to suggest that the degree of suppression of Austrodanthonia by Vulpia was less under elevated CO₂. These results do not support the initial advantage hypothesis, as Vulpia was always able to suppress Austrodanthonia, regardless of the initial relative sizes of the competitors. Furthermore, the lack of an effect of changing the CO₂ or temperature environment on the direction of interspecific competition suggests that the competitiveness of the invasive Vulpia will be minimally affected by changes in atmospheric CO₂ concentration or temperature.     

Male-Induced Sociosexual Behavior by Vaginal Secretions in Macaca arctoides

Odor communication in Old World monkeys and apes is controversial, because most females have evolved visual and behavioral cues to signal fertility, e.g., sexual swellings. Female stump-tailed macaques (Macaca arctoides) do not have swellings, and mediation of chemical communication likely occurs because males engage in sexual behavior mostly throughout the periovulatory phase of the menstrual cycle. We tested whether vaginal secretions from different cycle phases, with saline solution as a control, promote changes in the frequency of male genital exploration, copulation, and coercive behavior toward females different from the donors, while female donors were apart from the group. Males explored more female genitals when exposed to follicular, periovulatory, and early luteal secretions in comparison to saline or menstrual or late luteal secretions. The increase in coercive behavior after exposure to follicular and periovulatory secretions most likely was a male response to the lack of cooperation of target females in engaging in copulation, as the latter were not receptive during the tests. The strength of male response to vaginal secretions varied significantly as a result of individual variability between donor females, yet the variability does not correlate either to dominance rank or to female age. Exploratory behavior of males correlates significantly with their social rank. Our results suggest that vaginal secretions are among the cues that male Macaca arctoides use to acknowledge the reproductive status of females in the absence of visual signals.