A Novel Form of Phenotypic Plasticity of the Thermal Reaction Norms for Development in the Bug Graphosoma lineatum (L.) (Heteroptera,Pentatomidae)

Entomological Review - The temperature dependence of the developmental rate of ectothermic organisms may change under the influence of abiotic and biotic environmental factors that modify the...     

Effect of benzamide derivatives on rat brain monoamine oxidase activity in vitro

The ability of moclobamide and other benzamide derivatives to inhibit the activity of monoamine oxidase in the rat brain was studied. Distinct effects of these compounds on the deamination of serotonin and norepinephrine (MAO-A substrates); 2-phenylethylamine (selective MAO-B substrate); tyramine and dopamine (MAO-A and MAO-B substrates) are shown. It was demonstrated that among all the compounds studied moclobamide appeared to be the most active and selective inhibitor of MAO-A: at a concentration of 100 microM it caused a 100% inhibition of serotonin and norepinephrine deamination, which might be explained by the presence of C1 atom in the para-position of benzene ring in moclobamide molecule. Other benzamide derivatives were less active in inhibiting MAO-A and had but a negligible effect on dopamine- and 2-phenylethylamine deamination.     

Photoperiod modifies thermal reaction norms for growth and development in the red poplar leaf beetle Chrysomela populi (Coleoptera: Chrysomelidae)

Regression lines of development rate on temperature appeared significantly different between long (22 h) and short (12 h) day conditions and intersected each other at 23.8 °С. Thus, the rate of growth and development was higher at temperatures below the intersection point under short-day but above the intersection point it was higher under long day. Ecological relevance of this effect seems as follows: in autumn, as nights become longer and average daily temperature decreases, larvae have to speed up their development because it is only imago that overwinters. Conversely, midsummer offers long days and usually higher temperature, so again it is advantageous to develop as fast as possible in order to have at least one more generation per year. These results are compared with other studies showing interactions between photoperiod and temperature, and some possible general patterns are outlined. The lower thermal threshold for larval development depended on photoperiodic conditions; therefore rate isomorphy must be violated in this species. Development at higher temperatures generally resulted in smaller adults, as is usual with ectotherms according to the “temperature-size rule”, but body weight depended significantly on temperature only under short day. Our estimates of the lower temperature thresholds for growth and development in both cases did conform to the generalization made previously by Walters and Hassall (2006) in spite of another formula used by us. We briefly discuss this phenomenon and argue that relative position of these thresholds can be explained mathematically and per se may lack any biological sense.     

Temperature and photoperiodic control of diapase induction in the ant <Emphasis Type="Italic">Lepisiota semenovi</Emphasis> (Hymenoptera,formicidae) from Turkmenistan

The ants L. semenovi has been found to belong to species with endogenous-heterodynamic seasonal life cycles with the obligate diapause induced predominantly by factors internal for a colony, whereas external ecological factors (photoperiods and temperature) produce merely modifying effects by accelerating or delaying the diapause onset. The photoperiodic and temperature regulation of diapause induction in larvae and queens is shown. Under effect of short days and low temperature the periods of larval pupation and queen oviposition in a colony are shortened markedly, i.e., the diapause of larvae and queens occurs earlier. The daily rhythms of temperature 15/25°C and particularly 20/30°C as compared with constant temperatures 20 and 25°C that correspond to the mean circadian temperatures of the thermorhythm, inhibit manifestations of the short day effects by stimulating the non-diapause development and increasing duration of the seasonal development cycle of ant colonies. The L. semenovi photoperiodic reaction is quantitative, as development and pupation of larvae and egg-laying of queens cease sooner or later under both the short and the long days, but in the latter case significantly later. Thus L. semenovi is one more example among very rare ant species that are revealed to have the photoperiodic regulation of the colony development seasonal cycle.     

Metabotropic glutamate receptors in mechanisms of plasticity of the central nervous system in the honeybee <Emphasis Type="Italic">Apis mellifera</Emphasis>

Localization of metabotropic glutamate receptors (MGR) in head ganglion of honeybee Apis mellifera, and mechanisms of participation of activated MGR in CNS plasticity are investigated by means of complex approach using immunochemical, electrophysiological and behavioral methods. Influence of MGR activation on GABAergic system and inotropic glutamate receptors (IGR) of AMPA- and NMDA-subtypes is studied. MGR are revealed in lateral and medial calices of mushroom bodies. The inhibiting influence of MGR on AMPA- and NMDA receptors is shown using method of conditioned reflex. Previous activation of MGR neutralizes the inhibiting effect of GABA. Modulating role of heterogeneous MGR population in mechanisms of CNS plasticity on the level of glutamatergic synapse, and at interaction with GABAergic system is discussed.     

L-Glutamate in formation of long-term memory in the honeybee <Emphasis Type="Italic">Apis mellifera</Emphasis>

Participation of metabotropic glutamate receptors (mGluR) in associative learning of the honeybee Apis mellifera was studied in behavioral and electrophysiological experiments with use of pharmacological analysis. By the method of conditioned reflexes, effects of systemic injections of mGluR agonists and antagonists were studied on retention of elaborated conditioned reflexes in short-term and long-term memory. Injection of aminocyclopentandicarbonic acid (ACPD), ibotenate, and phosphoserine stimulated the memory in 3 h after the single learning procedure. The long- term memory was inhibited by mGluR antagonists — methylcarboxyphenylglycine and amino- phosphonopropionate as well as by non-competitive antagonists of mGluR₁(CPCCOEt) and of mGluR₅ (SIB 1757). Electrophysiological experiments demonstrated changes of characteristics of the action potential recorded from mushroom bodxies in response to stimulation of antennal lobes and during injections of mGluR III phosphoserine and the mGluR₁ antagonist CPCCOEt. The obtained data allow suggesting participation of different groups of metabotropic glutamate receptors in the process of the honeybee associative learning.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 40, No. 6, 2004, pp. 539–545.     

The study of mosquito fauna (Diptera, Culicidae) in Volgograd city in light of the outbreak of West Nile fever in Volgograd region, 1999

Mosquito sampling was carried out in Volgograd city and its vicinity in August 2001 and 2002. In total 16,000 individuals belonging to 6 genera and 12 species were collected. Nine species were anthropophilic. Culex modestus and Aedes vexans dominated in all outdoor samples collected in Volgograd city. In addition to these species, Coquillettidia richiardii and Ae. caspius were abundant in the vicinity of Volgograd. Autogenous Cx. popiens dominated among six species sampled indoors in Volgograd city. The possible role of different mosquito species in West Nile virus circulation in Volgograd city is discussed.     

Lanthanides induce neurotransmitter release from the vesicular pool in rat brain synaptosomes

The influence of lanthanoids on exocytosis was investigated. It was shown that gadolinium increases the spontaneous release of the glutamate nonmetabolizing analogue [3H]D-aspartate. It was established using the fluorescent dye acridine orange that gadolinium and lanthanum induce exocytosis. The effect was dose-dependent and was maximum at 300 microM Gd3+. The exocytosis induced by gadolinium was calcium-independent. It is suggested that lanthanides induce a vesicular release of neurotransmitters by the mechanisms common for all polyvalent cations.     

Changes in secretion of sex steroid hormones during stress in rats with various brain excitability

A stress procedure decreased the plasma progesterone faster in highly excitable rats than in the less excitable those. The decrease in gonadal and adrenal progesterone was still obvious in 24 hours in both groups of rats but more obvious in the former group in respect to the progesterone level. The data obtained may help to understand individual ability to respond to a stress in a different way depending on functional condition of the hypothalamo-pituitary-adrenal axis.