Lipophorin uptake by the larval fat body and adult ovary in the wax moth Galleria mellonella

Lipophorin (Lp) acts in the circulation of insects to selectively deliver lipids to target tissues. In the present study, we wanted to show that Lp is taken up into larval fat body cells and the adult ovary in Galleria mellonella. Larval fat body and adult ovary tissues were incubated at room temperature for 30 min with fluorescein isothiocyanate (FITC)‐labeled Lp. Fluorescence microscopy and sodium dodecylsulfate (SDS)–polyacrylamide gel electrophoresis (PAGE) revealed that fat body and ovary tissues internalize fluorescence‐labeled Lp. The results suggest that both lipids and proteins are taken up by fat body cells and the ovary and also that large amounts of proteins and lipids taken up can serve as building blocks and as a source of energy. Immunological relationships with other insects were investigated using western blotting. The data showed that the Lp of Galleria mellonella is related to that of Hyphantria cunea.     

Energy Budgets for Eared Grebes on the Great Salt Lake and Implications for Harvest of Brine Shrimp

ABSTRACT About 1.5-million eared grebes (Podiceps nigricollis), representing half of the North American population, stage on Utah's Great Salt Lake, USA (GSL) during autumn migration to forage on brine shrimp (Artemia franciscana). Indirectly competing with birds for brine shrimp are commercial harvesters who annually collect >1 million kg (dry wt) of shrimp cysts (i.e., hardened eggs), an amount that during some years equals up to half of all brine shrimp cysts produced annually on the GSL. No information was available regarding what impact this commercial harvest was having on eared grebes. We determined daily energy requirements of eared grebes so that regulations governing brine shrimp cyst harvest would better reflect foraging needs of grebes. We measured basal metabolic rate (BMR) of eared grebes from June 2000 to October 2000. Mean BMR of 106 adult and subadult eared grebes was 0.023 kJ/g/hour (SD = 0.004), and mean BMR of 37 juveniles was 0.024 kJ/g/hour (SD = 0.003). Resting and preening metabolic rates were 1.2 times higher than BMR, whereas diving-bout metabolic rate was 1.7 times higher than BMR. Daily energy needs of an average-sized grebe (550 g) during November were 391 kJ. Meeting this energy need requires daily consumption of 24,400 adult brine shrimp. In addition, grebes must consume 2,100–5,200 adult shrimp daily to obtain enough energy reserves to continue their migration to California, USA, and Mexico. Hence, grebes need to consume 26,500–29,600 adult brine shrimp daily while staging on GSL. To achieve this high harvest rate, grebes need adult brine shrimp densities at >380 shrimp/m³during autumn. Commercial harvest of brine shrimp cysts from GSL should be curtailed when cyst densities fall below 20,000 cysts/m³to ensure enough adult brine shrimp for grebes during the subsequent year.     

Inhibition by kinetin of cell elongation and RNA synthesis in excised soybean hypocotyl M 2

The effects of kinetin on growth and RNA metabolism in excisedsoybean hypocotyl were investigated, and compared to the effectsof 5-fluorouracil. Kinetin inhibits auxin-induced growth, butnot control growth. RNA synthesis is also inhibited by kinetin,but in a differential fashion. Ribosomal RNA synthesis is almostcompletely inhibited, while TB-RNA synthesis is partially inhibited.D-RNA synthesis is apparently not affected. Base compositionanalysis of these fractions of RNA was carried out. The implicationsfor RNA-mediated auxin-induced growth are discussed. ¹The research was supported by NIH grant GM-10157 from the U.S. Public Health Service. ²Purdue University AES Paper No. 3334     

Agricultural land use and Skylark Alauda arvensis: a case study linking a habitat association model to spatially explicit change scenarios

The development of forward scenarios is a useful method of envisaging the environmental implications of potential changes in land use, as a tool for policy development. In this paper, a spatially explicit case study is used to provide insight into the environmental impacts of Common Agricultural Policy reform on Skylark Alauda arvensis, a species which is widespread on arable farmland, breeds in crops and has declined in recent decades. A generalized linear mixed model was used to estimate Skylark breeding population densities in different crops, using survey data collected from farms in the east of England, supplemented by the literature. Model outputs were then used to predict Skylark densities in an East Anglian Joint Character Area dominated by arable cropping. Predicted densities were mapped at field level using GIS, based on actual cropping derived from Integrated Administration and Control System data collected for the administration of subsidy payments. Three future scenarios were then created, based on expert opinion of potential changes in cropping over the next 5 years, and potential changes in Skylark density mapped on the basis of the predicted changes in cropping patterns. Overall, Skylark densities were predicted to decrease on average by 11–14% under ‘market‐led’ (increasing wheat and oilseed rape, reduced set‐aside) and ‘energy crop’ (5% area under short rotation coppice) scenarios, but remained virtually unchanged under an ‘environment‐led’ (diverse cropping) scenario. The ‘market‐led’ scenario is closest to short‐term agricultural trajectories, but wider cultivation of biomass energy crops as modelled under the ‘energy crop’ scenario could occur in the medium term if energy policies are favourable. Appropriate mitigation strategies therefore need to be implemented if a continued decline in the Skylark population on lowland arable farmland is to be averted. The results provide a readily accessible visualization of the potential impacts of land‐use change for policy‐makers; similar techniques could be applied to visualize effects of changes arising through other drivers, including climate change.     

Genetic patterns across multiple introductions of the globally invasive crab genus Carcinus

The European green crab Carcinus maenas is one of the world's most successful aquatic invaders, having established populations on every continent with temperate shores. Here we describe patterns of genetic diversity across both the native and introduced ranges of C. maenas and its sister species, C. aestuarii, including all known non‐native populations. The global data set includes sequences from the mitochondrial cytochrome c oxidase subunit I gene, as well as multilocus genotype data from nine polymorphic nuclear microsatellite loci. Combined phylogeographic and population genetic analyses clarify the global colonization history of C. maenas, providing evidence of multiple invasions to Atlantic North America and South Africa, secondary invasions to the northeastern Pacific, Tasmania, and Argentina, and a strong likelihood of C. maenas × C. aestuarii hybrids in South Africa and Japan. Successful C. maenas invasions vary broadly in the degree to which they retain genetic diversity, although populations with the least variation typically derive from secondary invasions or from introductions that occurred more than 100 years ago.     

Properties of Phenylalanyl-tRNA Synthetase and Phenylalanine Ammonia-lyase of Pine Suspension Cultures

Phenylalanyl-tRNA synthetase and phenylalanine ammonia-lyase activities were demonstrated in partially purified extracts of pine (Pinus elliottii) suspension cultures. The optimum pH for the phenylalanyl-tRNA synthetase reaction was 7.5 and the optimum ATP and Mg²⁺ concentrations were 1.0 and 15 mM respectively. Pine, calf liver and yeast tRNA were inadequate substitutes for pea tRNA in the synthetase reaction mixtures. The optimum pH for the phenylalanine ammonia-lyase reaction was 9.0. The K_m for phenylalanine was approximately 6.6 × 10^?5M. The activity of both enzymes in the partially purified extracts was unstable on storage.     

Chill-induced wilting and hydraulic recovery in mung bean plants

• 1 The hydraulic conductance of roots of chilling-sensitive mung bean plants is reduced markedly at low temperatures. When roots are chilled suddenly under high irradiance, or when plants with roots chilled in the dark are exposed to a natural dawn, the stomata remain open for several hours. During this period the plants may wilt severely if the evaporative demand is sufficiently large. Under lower evaporative demand and less severe wilting, the plants may subsequently rehydrate.
• 2 Following root chilling there is a rapid (> 30 min) initial change in root conductivity (3. 2- fold).
• 3 Within hours the hydraulic conductivity of the pathway from stem xylem to leaf tissue decreases dramatically.
• 4 Within 1 d, the hydraulic conductivity of the roots decreases further (4. 5-fold).
• 5 Over 5 d these large resistances disappear and conductivity recovers to a value greater than at the start of chilling. This response and stomatal closure allow the plant to rehydrate to a condition similar to that of controls.
• 6 There is no simple relation between this hydraulic recovery and the accumulation of abscisic acid in the roots.