Poleward increase in feeding efficiency of leafminer Stigmella lapponica (Lepidoptera: Nepticulidae) in a latitudinal gradient crossing a boreal forest zone

Damage to plant communities imposed by insect herbivores generally decreases from low to high latitudes. This decrease is routinely attributed to declines in herbivore abundance and/or diversity, whereas latitudinal changes in per capita food consumption remain virtually unknown. Here, we tested the hypothesis that the lifetime food consumption by a herbivore individual decreases from low to high latitudes due to a temperature-driven decrease in metabolic expenses. From 2016 to 2019, we explored latitudinal changes in multiple characteristics of linear (gallery) mines made by larvae of the pygmy moth, Stigmella lapponica, in leaves of downy birch, Betula pubescens. The mined leaves were larger than intact leaves at the southern end of our latitudinal gradient (at 60°N) but smaller than intact leaves at its northern end (at 69°N), suggesting that female oviposition preference changes with latitude. No latitudinal changes were observed in larval size, mine length or area, and in per capita food consumption, but the larval feeding efficiency (quantified as the ratio between larval size and mine size) increased with latitude. Consequently, S. lapponica larvae consumed less foliar biomass at higher latitudes than at lower latitudes to reach the same size. Based on space-for-time substitution, we suggest that climate warming will increase metabolic expenses of insect herbivores with uncertain consequences for plant–herbivore interactions.     

Urinary excretion of PGE2 and renal function in acute myocardial infarction

In 17 hospitalized patients affected by acute myocardial infarction (AMI) PGE2 urinary excretion, renal function and, furthermore, cortisol urinary excretion were tested during a 21 days trial. In 12 patients all the parameters under consideration underwent a similar trend: PGE2 urinary excretion exactly like glomerular filtration rate, Na+ excretion and diuresis tended to be reduced during the first 5 days and they rapidly recovered the normality after this period. Cortisol urinary excretion displayed a characteristic pattern: i.e. the highest values were observed in the first days, followed by a progressive decrease towards physiological levels since the 4th day. Different findings were obtained in 5 cases treated with an antiinflammatory drug (Indoprophen i.m. 200 mg x2 die). In fact the low levels of urinary PGE2 on the first days did not display any increasing and GFR, urinary flow, and Na+ tubular balance underwent irregular and not significant variations. These data suggest that an impaired Prostaglandin synthesis may be related to a compromised renal function often occurring in AMI.     

Regions of homology in small colicinogenic plasmids

Restriction maps have been constructed for the colicinogenic plasmids (ColA, ColD, and ColK. Their regions of homology with the ColE1 plasmid and its deletion derivative pAO3 carrying the region responsible for autonomous replication of ColE1 plasmid were determined by means of blotting hybridization and heteroduplex analysis. The plasmids ColA, ColD, and ColK were shown to contain DNA fragments homologous to the region of ColE1 involved in the regulation of replication.     

Imidazolic H2-agonists: importance of 2-amino substitution for pharmacological activity

The results of 2-aminohistamine (compound I) and 2-amino-5-methylhistamine (compound II) on cat acid secretion and on guinea pig gall-bladder motility are described and compared with those of Histamine or Dimaprit. The compound (I) showed a greater H2- than H1-receptor stimulating activity, while compound (II), inactive on H1, was effective on H2-receptors, being endowed with a less "potency" and "efficacy" than compound (I). The pharmacological activities of both compounds, related to their chemical structure, are discussed.     

Practical synthesis of O-β-d-mannopyranosyl-, O-α-d-mannopyranosyl-, and O-β-d-glucopyranosyl-(1→4)-O-α-l-rhamnopyranosyl-(1→3)-d-galactoses

The koenigs-Knorr glycosylation of 4,6-O-ethylidene-1,2-O-isopropylidene-3-O-(2,3-O-isopropylidene-α-l-rhamnopyranosyl)-α-d-galactopyranose (3) by 4,6-di-O-acetyl-2,3-O-carbonyl-α-d-mannopyranosyl bromide (10), as well as Helferich glycosylations of 3 by tetra-O-acetyl-α-d-mannopyranosyl and -α-d-glucopyranosyl bromides, proceeded smoothly to give high yields of trisaccharide derivatives (12, 16, and 17). An efficient procedure for the transformation of 12, 16, and 17 into the α-deca-acetates of the respective trisaccharides has been developed. Zemplén de-acetylation then afforded the title trisaccharides in yields of 53, 52, and 62 %, respectively, from 3. A new route to 1,4,6-tri-O-acetyl-2,3-O-carbonyl-α-d-mannopyranose is suggested.     

Glycosylation by d-fructofuranose thio-orthoesters

The capsular polysaccharide from Klebsiella type K54, containing both O-formyl and O-acetyl groups, has been investigated by using the techniques of methylation analysis (by gas-liquid chromatography), periodate oxidation-Smith degradation, and both ¹H- and ¹³C-n.m.r. spectroscopy. Degradation of the native polysaccharide with a bacteriophage-induced glucosidase generated a formylated, as well as a formylated and acetylated, tetrasaccharide, whereas similar depolymerization of the deacetylated polysaccharide yielded a single tetrasaccharide; the corresponding, O-acylated octasaccharides were also isolated and characterized. These oligosaccharides, utilized in chemical and spectroscopic studies in order to determine the location of the O-acyl substituents in the repeating sequence, indicated formylation at O-4 of each lateral d-glucosyl group and acetylation at O-2 of alternate l-fucosyl residues. A new structure for the repeating unit in the polysaccharide is proposed.     

Interaction of adrenergic and purinergic receptors in the regulation of rat myocardial contractility in postnatal ontogeny

β-Adrenergic receptor agonist isoproterenol and purinergic receptor agonist 2-methylthio-ATP have a positive effect on the myocardial contractile force and show different efficiencies depending on the age of animals. The maximum inotropic effect of agonists on the ventricular myocardial contractility was observed in 21-day-old rat pups. The study of a combined effect of isoproterenol and 2-methylthio-ATP showed that an increase in the sympathetic regulatory effects on the heart of 21-day-old animals, against the background of a high functional activity of β-adrenergic receptors and P2X receptors of the heart, a combined administration of the agonists led to a mutually complementing effect of an increase in the myocardial contractility.     

Decline of Eulia ministrana (Lepidoptera: Tortricidae) in polluted habitats is not accompanied by phenotypic stress responses

Environmental pollution is currently identified as one of the major drivers of rapid decline of insect populations, and this finding has revitalized interest in insect responses to pollution. We tested the hypothesis that the pollution-induced decline of insect populations can be predicted from phenotypic stress responses expressed as morphological differences between populations inhabiting polluted and unpolluted sites. We explored populations of the brassy tortrix Eulia ministrana in subarctic forests along an environmental disturbance gradient created by long-lasting severe impacts of aerial emissions of the copper–nickel smelter in Monchegorsk, northwestern Russia. We used pheromone traps to measure the population densities of this leafrolling moth and to collect specimens for assessment of three morphological stress indices: size, forewing melanization, and fluctuating asymmetry in wing venation. Wing length of E. ministrana increased by 10%, and neither forewing melanization nor fluctuating asymmetry changed from the unpolluted forest to the heavily polluted industrial barren. However, the population density of E. ministrana decreased 5 to 10 fold in the same pollution gradient. Thus, none of the studied potential morphological stress indicators signaled vulnerability of E. ministrana to environmental pollution and/or to pollution-induced environmental disturbance. We conclude that insect populations can decline without any visible signs of stress. The use of morphological proxies of insect fitness to predict the consequences of human impact on insect populations is therefore risky until causal relationships between these proxies and insect abundance are deciphered.