Olfactory cues in discrimination among individuals in dominance hierarchies in the cockroach, Nauphoeta cinerea

ABSTRACT. The purpose of this study was to explore the olfactory recognition mechanisms used by individual subordinate male cockroaches, Nauphoeta cinerea (Olivier), in a dominance hierarchy. Results of two independent sets of experiments, one using an olfactometer and the other using an arena, suggest that olfactory cues are important to males. Subordinate males did not avoid dominant male odour in an olfactometer but could discriminate between the odours of familiar and unfamiliar individual dominant males, preferring the odour of the dominant male with which they had previous social contact. Since test subordinates did not avoid dominant male odours in the olfactometer, it is possible that the distance an individual remains from a dominant is important. To test this, individual dominant and subordinate males were tethered in the centre of an arena. Subordinate males were introduced into the arena and allowed to approach the tethered male. They approached tethered dominants and subordinates differently, and tended to keep away from the dominants. Tethered males unfamiliar to the test animals were avoided as well.     

Pheromone, juvenile hormone, and social status in the male lobster cockroach Nauphoeta cinerea

In this study, the major pheromone component, 3‐hydroxy‐2‐butanone (3H‐2B), released by dominants was measured during early scotophase. Both the JH III titer in the hemolymph and the 3H‐2B content of the sternal glands of the dominants and subordinates were then measured during late scotophase and late photophase. These investigations were performed on encounter days 1, 2, 3, 5, 7, 9, 12, and 20. The results showed that, for non‐aggressive posture (AP)‐adopting socially naïve males (SNMs), both the 3H‐2B release and the hemolymph JH III titer were maintained at a low level. Once a fight occurred, 3H‐2B release was raised significantly in the AP‐adopting dominants, but not in non‐AP‐adopting subordinates, and remained raised throughout the entire experimental period. At 30 min after the first encounter, the hemolymph JH III titer was significantly increased in dominants, but not in subordinates. A significantly higher hemolymph JH III titer was observed in dominants during late scotophase on days 3, 5, 12, and 20 and during late photophase on days 3, 5, and 20. After fighting, the sternal gland 3H‐2B content of the dominants or subordinates was significantly lower than in SNMs. In dominants, the sternal gland 3H‐2B content during late scotophase was significantly lower than that during late photophase in the first 9 domination days, while, in the subordinates, the 3H‐2B content during late scotophase was either similar to, or significantly higher than, that in late photophase. In the dominants, 3H‐2B release and JH III titer were positively correlated. In rank switchers, the switched social status was positively correlated with both 3H‐2B release and JH III titer. Comparison of 3H‐2B release and JH III titer in 1‐time, 3‐time, or 5‐time dominants showed that, although winning significantly increased both 3H‐2B release and JH III titer, there is no significant difference in 3H‐2B release between 3‐ and 5‐time winners, while the JH III titer was most significantly increased in the 3‐time winners. The possible relationship between pheromone release, JH III titer, and social status is discussed. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc.     

Sperm competition and male ejaculate investment in Nauphoeta cinerea: effects of social environment during development

Selective pressure arising from sperm competition has been predicted to influence evolutionary and behavioural adjustment of ejaculate investment, but also may influence developmental adjustment of ejaculate investment. Immature males able to target resources strategically based on the competitive environment they will experience when they become sexually mature should be at a selective advantage. In our study we investigated how the presence of potential competitors or mates affects ejaculate and testes investment during development in the cockroach Nauphoeta cinerea, a species where males control female remating via their ejaculate size (large spermatophores prevent females from remating and therefore function to avoid sperm competition for males) and females store sperm. Our aim was to determine whether the social environment influences developmental adjustment of ejaculate investment and the relative importance of ejaculate components with different functions; avoidance of or engagement in sperm competition. We conclude that the social environment can influence developmental and behavioural flexibility in specific ejaculate components that may function to avoid or engage in sperm competition.     

The influence of social experience on the behavior of male cockroaches,Nauphoeta cinerea

The influence of social experience on rates of agonistic behavior was investigated in a cockroach, Nauphoeta cinerea. Social experience was manipulated by establishing three types of groups of four identically aged males: (1) ran-domly chosen, socially naive males (control); (2) males of similar status and activity level (from treatment 1); and (3) males returned to their original hierarchy after experiencing treatment 2. In the control groups, we found stable hierarchies, significant differences in the rate of agonistic behaviors exhibited among different status males, and a significant relationship between social status and level of agonism. We also compare activity levels within and among groups after males had novel social experiences. Among similar status individuals, we found less activity than when they wereintheir original groups. When males were returned to their original groups, the level of activity increased compared to the level of activity before treatment. The social status of males was unstable after these treatments. Losing tended to result in relatively more subordinate behavior, and winning in relatively more dominant behavior by a male. Within groups, the rate of agonism also increased over 5 days in groups of males that had no previous interactions with each other, while the rate of agonism remained the same in groups of familiar males. We interpret these results in light of male-male assessment and the maintenance of social status in this species.     

Effect of the urease-derived peptide Jaburetox on the central nervous system of Triatoma infestans (Insecta: Heteroptera)

Background

Triatoma infestans is the main vector of Chagas'disease in Southern Cone countries. In triatomines, symptoms suggesting neurotoxicity were observed after treatment with Jaburetox (Jbtx), the entomotoxic peptide obtained from jackbean urease. Here, we study its effect in the central nervous system (CNS) of this species.

Methods

Immunohistochemistry, Western blots, immunoprecipitation, two-dimensional electrophoresis, tandem mass spectrometry and enzymatic assays were performed.

Results

Anti-Jbtx antibody labeled somata of the antennal lobe only in Jbtx-treated insects. Western blot assays of nervous tissue using the same antibody reacted with a 61 kDa protein band only in peptide-injected insects. Combination of immunoprecipitation, two-dimensional electrophoresis and tandem mass spectrometry identified UDP-N-acetylglucosamine pyrophosphorylase (UDP-GlcNAcP) as a molecular target for Jbtx. The activity of UDP-GlcNAcP increased significantly in the CNS of Jbtx-treated insects. The effect of Jbtx on the activity of nitric oxide synthase (NOS) and NO production was investigated as NO is a recognized messenger molecule in the CNS of T. infestans. NOS activity and NO levels decreased significantly in CNS homogenates of Jbtx-treated insects.

Conclusions

UDP-GlcNAcP is a molecular target of Jbtx. Jbtx impaired the activity of T. infestans nitrergic system, which may be related with early behavioral effects.

General Significance

We report that the CNS of Triatoma infestans is a target for the entomotoxic peptide and propose that a specific area of the brain is involved. Besides potentially providing tools for control strategies of Chagas' disease vectors our data may be relevant in various fields of research as insect physiology, neurobiology and protein function.     

一氧化氮在心肌缺血再灌注损伤中的调节作用 及相关治疗药物研究进展

一氧化氮 ( NO ) 是体内调节心血管系统功能的重要信号分子,在血管收舒、血小板活性调节、细胞增殖凋亡、氧化应激及炎症反 应等过程中发挥了不可或缺的作用。在心肌缺血再灌注过程中,随着一氧化氮合成酶表达和 NO 底物水平的动态变化,NO 生成的时间和 产量均会发生变化,导致其作用具有两面性。综述 NO 的产生与作用、在心肌缺血再灌注损伤中的作用和影响因素以及相关治疗药物及作 用机制的研究进展,为心肌缺血再灌注损伤的有效治疗和进一步研究提供参考     

Demonstration of a voltage dependent calcium current in follicles of the cockroach Nauphoeta cinerea

Summary

The electrical properties of vitellogenic cockroach follicles have been studied using a two-electrode voltage-clamp technique. The resting potential of freshly isolated follicles was usually between ?30 mV and ?45 mV. A voltage-dependent inward current could be activated when the follicles were placed in a medium containing high concentrations of either Ca²⁺ or Ba²⁺. Maximal current amplitudes were 0.8μA in a medium containing 30 mM Ca²⁺ and 2 μA in 30 mM Ba²⁺. Maximal amplitudes could be elicited with depolarizing pulses to about +15 mV. The steady-state inactivation curve indicated half maximal current at a holding potential of about ?20 mV. Co²⁺, Ni²⁺ and Mn²⁺ inhibited the divalent cation currents in a concentration dependent manner. Half maximal inhibition was observed at about 3 mM concentration for each of the inhibitory cations.     

Solubilization, identification, and localization of vitellogenin-binding sites in follicles of the cockroach, Nauphoeta cinerea

Binding sites for vitellogenin were solubilized and analyzed either with a filter assay or with ligand blotting. We tested sodium dodecylsulfate (SDS), Chaps, octyl-beta-D-glucoside, and sodium deoxycholate and found SDS and sodium deoxycholate to be most effective in solubilizing both high and low molecular weight binding sites. In the filter assay the sodium deoxycholate extracts, but not the SDS extracts, maintained binding activity after dilution of the solubilizer below its critical micellar concentration. In ligand blotting we consistently observed, in vitellogenic follicles, binding sites with an apparent Mr of approximately 200,000, 35,000, and three closely spaced bands between 14,000 and 20,000. Binding of vitellogenin to all binding sites was suppressed in the presence of the drug suramin. Analysis of corpora lutea and oothecae as well as of ovariole sheath, follicle cell/basal lamina, and oocyte plasma membrane preparations showed that the 35 and 14-20 kDa binding sites are located in the outer follicle compartments, and the 200 kDa binding site in the oocyte plasma membrane. In the latter we occasionally also observed binding sites with an apparent Mr of approximately 150,000, 95,000, 67,000 and 30,000, particularly at stages after ovulation. The 35 and 14-20 kDa binding sites, as visualized in stained gels and in ligand blotting, are rather abundant and were also seen in several other male and female tissues of Nauphoeta and even in other species. They also bound other 14C-labeled hemolymph proteins and thus appear to be rather unspecific. As binding analysis with nonsolubilized and sodium deoxycholate-solubilized membranes revealed that the quantity of vitellogenin bound by binding sites of the outer follicle compartments was low, it is conceivable that the abundance of the 14-20 kDa and 35 kDa binding sites in ligand blotting is merely an effect of SDS and does not reflect the in vivo situation. We suppose that the 200 kDa binding site of the oocyte plasma membrane represents the vitellogenin receptor involved in endocytosis.     

灰葡萄孢菌AUR1基因真核表达载体的构建、表达及酶活性分析

为了研究灰葡萄孢菌肌糖磷脂酰神经酰胺合成酶(BcAUR1基因)的表达及酶活性,采用RT-PCR方法,利用含有FLAG标签以及BamH Ⅰ、Xho Ⅰ酶切位点的AUR1特异引物从灰葡萄孢菌中扩增得到BcAUR1基因.将BcA UR1基因与穿梭质粒pYES2重组,得到pYES2-BcAUR1质粒采用醋酸锂转化法导入酿酒酵母尿嘧啶突变菌株△yor1中,Western blotting检测肌糖磷脂酰神经酰胺(IPC)合成酶表达,HPLC检测IPC合成酶活力.结果显示pYE S2-BcA UR1在酿酒酵母尿嘧啶突变菌株△yorl中获得表达,pYES2-BcA UR1转化子IPC合成酶活性显著增高,比空载转化子约提高1倍.低浓度的AbA能够抑制空载pYES2酵母转化子生长,但pYES2-BcA UR1酵母转化子能抵抗AbA对菌体生长的抑制.     

HIF-NOS信号通路对哺乳动物卵巢NO依赖性功能的调控作用

一氧化氮(NO)作为气体明星分子和信号分子,在哺乳动物体内不同的生理调节过程中具有非常重要的作用,尤其是哺乳动物卵巢功能的调控.一氧化氮合酶(NOS)是NO合成的限速酶,是调节NO合成的关键环节,也是NO依赖性功能调控的重要环节.因此,调节NOS转录/合成的信号通路对哺乳动物卵巢NO依赖性功能具有至关重要的调控作用.最近的研究发现,缺氧诱导因子(HIF)作为转录因子,参与许多与缺氧相关靶基因的转录调控,如NOS和血管内皮生长因子(VEGF)等.本文一方面描述了NO合成及其调控的分子机制,另一方面阐明了HIF作为转录因子对NOS的转录调控,从而揭示HIF在NO依赖性卵巢功能调控中的重要作用,同时为进一步研究哺乳动物卵巢功能的调控提供新的研究方向和理论基础.     

Effects of moderate hypothermia on constitutive and inducible nitric oxide synthase activities after traumatic brain injury in the rat

We investigated the effects of therapeutic hypothermia (30 degrees C) on alterations in constitutive (cNOS) and inducible (iNOS) nitric oxide synthase activities following traumatic brain injury (TBI). Male Sprague-Dawley rats were anesthetized with 0.5% halothane and underwent moderate (1.8-2.2 atm) parasagittal fluid-percussion (F-P) brain injury. In normothermic rats (37 degrees C) the enzymatic activity of cNOS was significantly increased at 5 min within the injured cerebral cortex compared with contralateral values (286.5+/-68.9% of contralateral value; mean+/-SEM). This rise in nitric oxide synthase activity was significantly reduced with pretraumatic hypothermia (138.8+/-17% of contralateral value; p < 0.05). At 3 and 7 days after normothermic TBI the enzymatic activity of cNOS was decreased significantly (30+/-8.4 and 28.6+/-20.9% of contralateral value, respectively; p < 0.05). However, immediate posttraumatic hypothermia (3 h at 30 degrees C) preserved cNOS activity at 3 and 7 days (69.5+/-23.3 and 78.6+/-7.6% of contralateral value, respectively; mean+/-SEM; p < 0.05). Posttraumatic hypothermia also significantly reduced iNOS activity at 7 days compared with normothermic rats (0.021+/-0.06 and 0.23+/-0.06 pmol/mg of protein/min, respectively; p < 0.05). The present results indicate that hypothermia (a) decreases early cNOS activation after TBI, (b) preserves cNOS activity at later periods, and (c) prevents the delayed induction of iNOS. Temperature-dependent alterations in cNOS and iNOS enzymatic activities may participate in the neuroprotective effect of hypothermia in this TBI model.     

Histological and cytological studies on the fat body of the cockroach Nauphoeta cinerea during the first reproductive cycle

Summary The central fat body of the ovoviviparous cockroach Nauphoeta cinerea was studied during the first reproductive cycle of the female by means of light microscopy, autoradiography and electron microscopy. Comparative studies in larval stages were also undertaken. The fat body of Nauphoeta contains a large amount of lipid droplets and the remaining cytoplasm is very scarce. The cytological cyclicity of the fat body is consistent with the known biochemical rhythms of vitellogenin production. The proteosynthetic apparatus appears about 3 days after imaginal ecdysis, along with vitellogenin. The ribosomal endoplasmic reticulum (RER) shows a tremendous increase by the 7th day of the first cycle. The most active period of vitellogenin production lasts from day 7 to day 12. The proteosynthetic apparatus then returns to an inactive stage and disappears. This inactive condition lasts to the end of the gestation period. The autoradiographic results are consistent with the cytological features.Work carried out under the scientific direction of Prof. M. Lüscher of the University of Bern and supported in part by a grant from the Swiss National Science Foundation (No 3. 633.71).     

Cellular mechanisms and intracellular signaling pathways for the modulation of eNOS in pulmonary arteries by 15-HETE

The 15-hydroxyeicosatetraenoic acid (15-HETE), a lipid metabolite and vasoconstrictor, plays an important role in hypoxic contraction of pulmonary arteries (PAs) through working on smooth muscle cells (SMCs). Previous studies have shown that vascular endothelium is also involved in PAs tone regulation. However, little is known as to how the pulmonary artery endothelial cells (PAECs) are related to the 15-HETE-induced vasoconstriction and that which intracellular signaling systems are critical. To test this hypothesis, we examined PAs constriction in isolated rat PAs rings, the expression and activity of endothelial nitric oxide synthase (eNOS) with western blot, and nitric oxide (NO) production using the DAF-FM DA fluorescent indicator. The results showed that the 15-HETE-induced PAs constriction was diminished in endothelium-intact rings. In the presence of the eNOS inhibitor L-NAME, vasoconstrictor responses to KCl were greater than the control. The activation of eNOS was activated by Ca²⁺ released from intracellular stores and the PI3K/Akt pathway. Phosphorylations of the eNOS at Ser-1177 and Akt at Ser-473 were necessary for their activity. A prolonged 15-HETE treatment (30?min) led to a decrease in NO production by phosphorylation of eNOS at Thr-495, leading to augmentation of PAs constriction. Therefore, 15-HETE initially inhibited the PAs constriction through the endothelial NO system, and both Ca²⁺ and the PI3K/Akt signaling systems are required for the effects of 15-HETE on PAs tone regulation.     

真菌激发子对桦褐孔菌多酚积累的影响

作者旨在阐明真菌激发子对桦褐孔菌多酚积累的影响。以摇瓶法培养桦褐孔菌,在其培养液中加入真菌激发子和一氧化氮合酶抑制剂氨基胍,观察桦褐孔菌多酚和一氧化氮的积累并测定菌丝体内一氧化氮合酶和苯丙氨酸解氨酶的活性。多酚以Folin-Ciocalteu法测定,一氧化氮的积累量用硝酸还原酶法测定,一氧化氮合酶和苯丙氨酸解氨酶活性均以分光光度计法测定。结果表明,添加45μg/mL的激发子可使桦褐孔菌菌丝体多酚的积累量达到46.5mg/g,显著地高于正常培养的菌丝体多酚积累量34.6mg/g;同时加入45μg/mL的激发子和10mmol/L氨基胍则使菌丝体多酚积累的最高水平降为34.8mg/g。此外,激发子的加入显著促进了一氧化氮的产生并提高了苯丙氨酸解氨酶活性,而这种促进和提升作用为氨基胍所抑制。这表明真菌激发子能显著地提升桦褐孔菌多酚类化合物的积累,而一氧化氮可能是这种提升作用的信号传导分子。     

胰岛素促进血管内皮细胞产生一氧化氮的实验研究

目的：探讨胰岛素对血管内皮细胞增殖、NO产生和NOS基因表达的影响。方法：培养牛主动脉内皮细胞,测定培养上清液中NO氧化产物NO2^－的水平并应用定量RT－PCR技术检测内皮细胞NOS mRNA的表达水平。结果：①胰岛素对大血管内皮细胞无细胞毒作用,也不影响细胞增殖;②在1－15μg/ml浓度范围内,胰岛素加强内皮细胞释放NO,且呈剂量依赖的方式,NOS特异性抑制剂L－NAME可阻抑之;③胰岛素轻度增加NOS mRNA表达水平,但无统计学意义。结论：胰岛素既不影响大血管内皮细胞增殖,也不影响内皮细胞NOS mRNA表达水平,但以剂量依赖的方式加强内皮细胞产生NO,推测其诱导NO产生的机制可能是通过酶活性的诱导,加速NO的合成。     

Alternative pathways of nitric oxide formation in Lactobacilli: Evidence for nitric oxide synthase activity by EPR

The study of the ability of Lactobacillus plantarum 8P-A3 to synthesize nitric oxide (NO) showed that this strain lacks nitrite reductase. However, analysis by the EPR method revealed the presence of nitric oxide synthase activity in this strain. Like mammalian nitric oxide synthase, lactobacillar NO synthase is involved in the formation of nitric oxide from L-arginine. L. plantarum 8P-A3 does not produce NO in the denitrification process. The regulatory role of NO in symbiotic bacteria is emphasixed.     

Effects of nitric oxide synthase inhibitors and a substrate,L-arginine,on the cardiac function of juvenile salmonid fish

Control of cardiac function was investigated juvenile brown trout (Salmo trutta L.) and rainbow trout (Oncorhynchus mykiss Walbaum) using inhibitors of nitric oxide synthase (NOS), (L-NAME, NG-nitro-L-arginine and L-NMMA, NG-monomethyl-L-arginine) and a substrate of NOS (L-arginine). Salmonid alevins are excellent models for such studies since they are transparent, the beating heart is easily observed, diffusing distances are small, and they respond within a few seconds to exogenously administered chemicals. The response to inhibitors of NOS (L-NAME or L-NMMA) was tachycardia interpreted as vasoconstriction through lowered capacity for synthesis of NO. This could be reversed by addition of L-arginine and the subsequent bradycardia was explained as a vasodilation resulting from increased synthesis of NO. Blood flow into the heart is mainly via the vitelline vein and changes of flow resulting from constriction or dilation of this vessel may be probably major determinants of heart rate. The results provide evidence for the presence NOS in juvenile fish and indicate a physiological role for NO in cardiovascular control.     

化湿液对湿阻证大鼠下丘脑AchE、NOS活性及NO含量的影响

目的研究化湿液对湿阻证模型大鼠下丘脑AchE、NOS活性及NO含量的影响。方法将50只SD大鼠随机分为正常组、模型组及模型组 化湿液低、中、高剂量组,每组10只。除正常组外,其余4组用改进后的环境加疲劳法制造湿阻证模型,连续造模6d。造模成功后,正常组和模型组大鼠按2ml/100g的剂量灌胃给予生理盐水;化湿液低、中、高剂量组分别按含生药0.4g/100g、0.8g/100g、1.6g/100g的剂量灌胃给予化湿液。每天1次,连续8d。取大鼠下丘脑,检测下丘脑AchE、NOS活性及NO含量。结果与正常组比较,模型组大鼠下丘脑AchE活性明显升高,NOS活性及NO含量明显降低(P<0.05);与模型组比较,化湿液可降低湿阻证模型大鼠下丘脑AchE的活性,提高下丘脑NOS活性及NO含量(P<0.05)。结论化湿液具有改善湿阻证大鼠下丘脑AchE、NOS活性及NO含量的作用,对研究化湿液治疗湿阻证的机制有一定价值。