Ovipositional site selection by Anopheles gambiae: influences of substrate moisture and texture

The influence of substrate moisture (hydration) and grain size (texture) on oviposition was quantified in choice tests using Anopheles gambiae sensu stricto Giles (Diptera: Culicidae) laboratory strains and gravid An. gambiae sensu lato from a natural population in Western Kenya. A strong, positive correlation was found between moisture content and the degree of egg-laying, which peaked at saturation with standing water. Soil moisture quantified as surface conductivity, was measured with an electronic leaf-wetness sensor slightly modified from a unit available commercially. Although An. gambiae females were sensitive to measurable differences in substrate moisture, they distributed eggs on both fully hydrated and less hydrated substrates. In contrast, An. gambiae females showed little response to substrate texture: they oviposited with equal frequency on all silica substrates of eight particle size classes, ranging from small pebbles (850 microm diameter) to very fine grains (< 38 microm diameter), when all were moist. Female An. gambiae laid more eggs on dark than white substrates against a light background, but did not discriminate between moist, pulverized black soapstone and moist black Kenyan soil taken from typical An. gambiae larval habitats. We conclude that hydration and visual contrast are critical ovipositional site qualities for An. gambiae, but substrate texture is not.     

Growth analysis of wild-type and photomorphogenic-mutant tomato plants

A custom designed growth-measuring apparatus, controlled by a microcomputer has been used to study extension growth kinetics of wild-type and photomorphogenic-mutant tomato ( Lycopersicon esculentum Mill.) plants with and without end-of-day farred light (EODFR). The following photomorphogenic mutants were used. Far-red insensitive ( fri ^.1): deficient in phytochrome A (phyA); temporarily red light-insensitive ( tri ^.3): deficient in phytochrome Bl (phyB1), and their isogenic wild type (WT) cv. MoneyMaker. aurea (au) : deficient in phytochrome chromophore biosynthesis; high-pigment-1 ( hp-1 ): exhibiting exaggerated phytochrome responses, and their isogenic WT cv. Ailsa Craig. The stem elongation rate (SER) during a 24-h period of all the genotypes studied shows a similar pattern, having two dramatic transients, one shortly after the onset of the light period (a sharp decline in SER) and another shortly after the start of the dark period (a sharp increase in SER). These transients are probably associated with water relations as a consequence of opening and closure of the stomata. The fastest SER occurs during the dramatic oscillations early in the dark period. Between the genotypes there are large quantitative differences in SER. All the genotypes tested exhibited a strong EODFR response, resulting in a relative promotion of SER during the first period after the start of EODFR and in the subsequent light and dark periods. These results indicate that phyA, absent in the fri ^.1 mutant, does not play a major role in SER of light-grown tomato plants, whereas phyB 1, absent in the tri ^.3 mutant, is partly responsible for the compact stature of WT plants. An additional phytochrome other than phy A and phy B1 must therefore be capable of eliciting the EODFR response.     

手持密度仪检测鸡与鸭精子密度技术的研究

精子密度仪在哺乳动物中已推广应用,但在家禽中还研究很少。本文以黑凤鸡和攸县麻鸭精液为实验材料,手持精子密度仪与血细胞计数板为检测工具,对影响精子密度测定方法准确率因素进行分析,建立鸡、鸭精子密度-吸光度函数并进行验证。结果表明:用密度仪测定时的稀释液(简称"测试液")为3%NaCl时,精液稀释后应尽快检测吸光度;样液在比色皿中的混匀方式对吸光度测定有很大影响;精液用3%NaCl以及3种常用家禽精液稀释液进行10倍稀释后测定吸光度,B液吸光度显著高于与其它3组(P<0.05),其它3组间差异不显著(P>0.05)。用测试液为3.0%NaCl,鸡和鸭精子密度-吸光度呈三次函数关系,回归方程分别是Y_1=1.374X^3-0.786X^2+0.945X-0.002(R^2=0.997)、Y_2=1.283X^3-0.899X^2+0.994X-0.009(R^2=0.996);用0.9%NaCl代替3%NaCl作测试液简化精子密度测定方法可行,鸡精子密度-吸光度回归方程为Y_3=-0.264X^3+1.23X^2+0.468X+0.019(R^2=0.999)。鸡精液测试液为0.9%NaCl、3%NaCl时两种函数的吸光度最佳范围分别是0.035～0.692、0.069～0.624,在此范围内计数板与方程两种方法得到的密度差异不显著(P>0.05),以计数法为真实值,两种方法平均相对误差分别为6.95%、3.11%。以3%NaCl为测试液,鸭精液函数所测样品吸光度最佳范围小于鸡精液的,以计数板法为真实值,在吸光度0.054～0.123范围内的,函数与计数板两种方法所得的精子密度的平均相对误差为4.61%。本文将促进家禽手持精子密度仪研发,以及更好的使用哺乳动物精子密度仪。     

Estimation of whole‐body SAR from electromagnetic fields using personal exposure meters

In this article, personal electromagnetic field measurements are converted into whole‐body specific absorption rates for exposure of the general public. Whole‐body SAR values calculated from personal exposure meter data are compared for different human spheroid phantoms: the highest SAR values (at 950 MHz) are obtained for the 1‐year‐old child (99th percentile of 17.9 µW/kg for electric field strength of 0.36 V/m), followed by the 5‐year‐old child, 10‐year‐old child, average woman, and average man. For the 1‐year‐old child, whole‐body SAR values due to 9 different radiofrequency sources (FM, DAB, TETRA, TV, GSM900 DL, GSM1800 DL, DECT, UMTS DL, WiFi) are determined for 15 different scenarios. An SAR matrix for 15 different exposure scenarios and 9 sources is provided with the personal field exposure matrix. Highest 95th percentiles of the whole‐body SAR are equal to 7.9 µW/kg (0.36 V/m, GSM900 DL), 5.8 µW/kg (0.26 V/m, DAB/TV), and 7.1 µW/kg (0.41 V/m, DECT) for the 1‐year‐old child, with a maximal total whole‐body SAR of 11.5 µW/kg (0.48 V/m) due to all 9 sources. All values are below the basic restriction of 0.08 W/kg for the general public. 95th percentiles of whole‐body SAR per V/m are equal to 60.1, 87.9, and 42.7 µW/kg for GSM900, DAB/TV, and DECT sources, respectively. Functions of the SAR versus measured electric fields are provided for the different phantoms and frequencies, enabling epidemiological and dosimetric studies to make an analysis in combination with both electric field and actual whole‐body SAR. Bioelectromagnetics 31:286–295, 2010. © 2009 Wiley‐Liss, Inc.     

Dmt-Tic-NH-CH2-Bid (UFP-502), a potent DOP receptor agonist: in vitro and in vivo studies

Knockout and pharmacological studies demonstrated that the activation of delta opioid peptide (DOP) receptors produces antidepressant-like effects in rodents. Here we report the results obtained with the novel DOP ligand H-Dmt-Tic-NH-CH₂-Bid (UFP-502). UFP-502 bound with high affinity (pK_i 9.43) to recombinant DOP receptors displaying moderate selectivity over MOP and KOP. In CHO_hDOP [³⁵S]GTPγS binding and mouse vas deferens experiments, UFP-502 behaved as a potent (pEC₅₀ 10.09 and 10.70, respectively) full agonist. In these preparations, naloxone, naltrindole and N,N(CH₃)₂Dmt-Tic-OH showed similar pA₂ values against UFP-502 and DPDPE and the same rank order of potency. In vivo in mice, UFP-502 mimicked DPDPE actions, producing a significant reduction of immobility time after intracerebroventricular administration in the forced swimming test and a clear antinociceptive effect after intrathecal injection in the tail withdrawal assay. However, while the effects of DPDPE were fully prevented by naltrindole those evoked by UFP-502 were unaffected (tail withdrawal assay) or only partially reversed (forced swimming test). In conclusion, UFP-502 represents a novel and useful chemical template for the design of selective agonists for the DOP receptor.     

Are Sclerophylls and Malacophylls Hydraulically Different?

This work tests the hypothesis that sclerophylls (i.e. hard-leaved species) would be less efficient than malacophylls (i.e. soft-leaved species) in terms of water transport through the stem as well as within the leaf blade. Mean leaf surface area (A_L), leaf specific mass (LSM) as well as shoot (K_WL), stem (K_SL) and leaf (K_LL) hydraulic conductances were measured in eight Mediterranean evergreen sclerophylls and eight temperate deciduous malacophylls. No difference was observed between the two groups in terms of K_LL and of the contribution of leaves to the overall shoot hydraulic resistance. Leaves represented in all cases 48 to 90 % of the shoot hydraulic resistance, suggesting that the sclerophyllous habitus does not per se lead to low efficiency in water transport within the leaf blade. A weak negative relationship (r² = 0.252) appeared to exist between K_SL and LSM. This might provide an explanation for the lower growth rates of sclerophylls with respect to malacophylls.     

Proximate composition,lipid utilization and validation of a non‐lethal method to determine lipid content in migrating American shad Alosa sapidissima

Lipid content forms the most important energy reserve in anadromous fish and can limit survival, migration and reproductive success. A fat meter was evaluated and compared with a traditional extractive method of measuring available lipid for migrating American shad Alosa sapidissima in the Connecticut River, U.S.A. The fat meter gives rapid (<10 s) and non‐lethal lipid measurements, whereas traditional methods require lethal sampling that is both time consuming and expensive. The fat‐meter readings had a strong relationship to traditional lipid extractions for 60 fish, 30 whole body (R² = 0·72) and 30 fillet only (R² = 0·81). Additional validation showed that fat‐meter readings captured the gradual decrease of lipid in individual fish over time, were not affected by removal of gonads or scales and were stable for fish exposed to water or air for 24 h after death. These experiments indicate that the fat meter can be used as a reliable tool for future A. sapidissima energetic studies, allowing for larger sample sizes and non‐lethal sampling.     

Seasonal and diurnal patterns of population vocal activity in avian brood parasites

Patterns of vocal activity may involve information about vocalizations themselves as well as their function. In birds, vocal activity at the individual and population level is generally closely associated with breeding cycles, reaching the peak during territorial and mating competition, and decreasing with the onset of egg incubation and chick feeding. However, little is known about patterns of vocal activity in avian brood parasites that have unusual breeding cycles without parental care. Using passive acoustic monitoring, we determined the seasonal and diurnal patterns of population vocal activity in two avian brood parasites: the Common Cuckoo Cuculus canorus and the Lesser Cuckoo C. poliocephalus. We found that both species and both sexes showed a similarly highly structured pattern of seasonal vocal activity, reaching a sharp peak in the early breeding season when birds compete for territories and mates, although males sang more frequently than females. Likewise, the diurnal patterns of vocal activity were similar in both species and both sexes of cuckoos, with peak activity occurring around dawn. Nocturnal calls by male cuckoos were also detected in both species, but only in the early breeding season. Collectively, the observed patterns of population vocal activity may suggest that the absence of parental care may not extend the period of vocal activity in these two species of brood parasites.