The control of Aphis fabae Scop, on spring-sown field beans (Vicia faba L.)

Disulfoton or phorate granules or demeton-S-methyl, menazon and vamidothion sprays, applied once in early June as preventive treatments before heavy aphid colonies developed, gave good control of Aphis fabae Scop, on field beans. Phosalone gave relatively poor results and DDT was ineffective. Applications in June to crops sown in February and early March were made with minimal wheel damage to the crop and are known to be less harmful to bees than sprays at flowering time. Eradicant treatments with demeton-S-methyl and dimethoate sprays or with disulfoton or phorate granules on heavily infested plants during flowering were also effective, but menazon was less satisfactory. These eradicant sprays are likely to be harmful to bees, and wheel damage in late June reduced yield by 1–2 cwt/acre (125–250 kg/ha). Peak populations of 3000 aphids/plant in early July reduced yield by 6 cwt/acre (750 kg/ha) in one trial.     

Population genetics and phylogenetics of DNA sequence variation at multiple loci within the Drosophila melanogaster species complex

Two regions of the genome, a 1-kbp portion of the zeste locus and a 1.1- kbp portion of the yolk protein 2 locus, were sequenced in six individuals from each of four species: Drosophila melanogaster, D. simulans, D. mauritiana, and D. sechellia. The species and strains were the same as those of a previous study of a 1.9-kbp region of the period locus. No evidence was found for recent balancing or directional selection or for the accumulation of selected differences between species. Yolk protein 2 has a high level of amino acid replacement variation and a low level of synonymous variation, while zeste has the opposite pattern. This contrast is consistent with information on gene function and patterns of codon bias. Polymorphism levels are consistent with a ranking of effective population sizes, from low to high, in the following order: D. sechellia, D. melanogaster, D.mauritiana, and D. simulans. The apparent species relationships are very similar to those suggested by the period locus study. In particular, D. simulans appears to be a large population that is still segregating variation that arose before the separation of D. mauritiana and D. sechellia. It is estimated that the separation of ancestral D. melanogaster from the other species occurred 2.5-3.4 Mya. The separations of D. sechellia and D. mauritiana from ancestral D. simulans appear to have occurred 0.58- 0.86 Mya, with D. mauritiana having diverged from ancestral D. simulans 0.1 Myr more recently than D. sechellia.      

Effects of different mesenchymal stromal cell sources and delivery routes in experimental emphysema

We sought to assess whether the effects of mesenchymal stromal cells (MSC) on lung inflammation and remodeling in experimental emphysema would differ according to MSC source and administration route. Emphysema was induced in C57BL/6 mice by intratracheal (IT) administration of porcine pancreatic elastase (0.1 UI) weekly for 1 month. After the last elastase instillation, saline or MSCs (1×10⁵), isolated from either mouse bone marrow (BM), adipose tissue (AD) or lung tissue (L), were administered intravenously (IV) or IT. After 1 week, mice were euthanized. Regardless of administration route, MSCs from each source yielded: 1) decreased mean linear intercept, neutrophil infiltration, and cell apoptosis; 2) increased elastic fiber content; 3) reduced alveolar epithelial and endothelial cell damage; and 4) decreased keratinocyte-derived chemokine (KC, a mouse analog of interleukin-8) and transforming growth factor-β levels in lung tissue. In contrast with IV, IT MSC administration further reduced alveolar hyperinflation (BM-MSC) and collagen fiber content (BM-MSC and L-MSC). Intravenous administration of BM- and AD-MSCs reduced the number of M1 macrophages and pulmonary hypertension on echocardiography, while increasing vascular endothelial growth factor. Only BM-MSCs (IV > IT) increased the number of M2 macrophages. In conclusion, different MSC sources and administration routes variably reduced elastase-induced lung damage, but IV administration of BM-MSCs resulted in better cardiovascular function and change of the macrophage phenotype from M1 to M2.     

Effect of the Shoot on the Transmembrane Potentials of Root Cortical Cells of Sunflower

Transmembrane potentials (PD) of root cortical cells were measuredbetween the vacuole and the external solution while the rootsremained attached to the plants. External solution concentrationwas varied by using a range of dilutions of a balanced nutrientsolution. In all cases the PD was more negative than that dueto diffusion alone indicating the presence of an electrogenicor metabolically derived component. This component contributedan additional –80 mV to the PD and was relatively independentof the external solution concentration. The metabolic componentwas eliminated by metabolic inhibitors, placing the shoot indarkness, ringing the phloem, or severing the rootlet from theshoot; it was restored again by removing the inhibitor, by light,or, in the case of severance, by adding 25 mM sucrose to themedium. The magnitude of the electrogenic component of the PDwas dependent on the antecedent light intensity in a way reminiscentof translocation itself.     

The diet and dentition of Smooth newt larvae (Triturus vulgaris)

This paper describes the dentition and diet of a population of Smooth newt larvae. The development of the teeth and their increase in number with age are discussed. The number of teeth on all five tooth-bearing bones appear to be controlled by a single developmental system. Young larvae eat chydorids, daphniids and cyclopoid copepods; after they reach a total length of about 15 mm, chironomid larvae comprise the greater part of the diet. In the study population, ostracods were not eaten, and cannibalism was not observed. There was no tendency for larger larvae to select larger individuals of a given species of prey.
It is suggested that the exponential rate of growth in weight forces larvae of more than about 15 mm total length to switch from passive to active hunting. This enables them to catch larger prey, at the expense of incurring a higher rate of mortality. This increase in mortality is associated with a reduction in the variation of morphological characters, including dentition, which is thought to be caused by natural selection. The function of different components of the dentition are discussed. It was found that larvae of a given age which have more teeth than average have in their guts fewer prey than average, and an explanation is suggested.