The use of weasels for natural control of mouse and vole populations in a coastal coniferous forest

Summary Nectar-feeding frequently occurs in male and female tabanids. 53% of the 7,002 females and 69% of the 2,436 males reacted positively to cold anthrone. Although there are seasonal fluctuations in rates of blood and nectar-feeding, the acquisition of sugars may be essential for tabanid survival during the summer. Differences in blood-feeding rates among the species may indicate different blood-sucking habits.This work is a part of Ph.D. thesis carried out at the Institut für Allgemeine und Spezielle Zoologie, Justus-Liebig-Universität Gießen     

Children seen frequently out of hours in one general practice.

OBJECTIVE--To identify reasons why some children receive more out of hours visits than most. DESIGN--A one year prospective study to identify the study group. This was followed by a case-control study involving a record search and personal interviews. SETTING--One three doctor urban general practice in West Lothian with 4812 patients. SUBJECTS--40 children aged under 10 years identified as high users of the out of hours service (more than two visits a year) and 40 age and sex matched controls. MAIN OUTCOME MEASURES--Numbers of visits; social factors such as lone motherhood, low educational attainment; score for management response to clinical vignette. RESULTS--147/756 (19%) out of hours visits in the study year were to children aged under 10 years; 109 (74%) to 41 children (6%). Problems seen were mainly minor, and little active management was required. Family and social factors which were significantly more common for the cases than for the controls included a lone mother (15 v 4), low educational attainment by the mother (25 v 14), receipt of income support (22 v 7), and non-ownership of the home (45 v 22) or a car (19 v 9). Mothers of the cases were more likely to choose to contact a doctor when presented with vignettes describing common childhood illnesses (median score for 16 vignettes 16.5 for cases v 14.5 for controls, Wilcoxon signed rank test, p = 0.01). CONCLUSIONS--Children seen more frequently than expected out of hours came from more socially disadvantaged families and their mothers were more likely to seek medical advice about minor childhood illness. Maternal education, to promote confidence in managing minor illness, may reduce their use of the out of hours service.     

The effect of rearing history and aphid density on volatile‐mediated foraging behaviour of Diaeretiella rapae

1. Parasitoid females foraging for hosts rely on cues derived from the insect host, the host plant and/or their interaction, and all of these can be learned during the immature and adult stages. 2. The present study investigated the importance of rearing history on foraging behaviour of Diaeretiella rapae, an endoparasitoid often associated with aphids feeding on brassicaceous plant species. 3. Parasitoids were reared on one of the four possible combinations, comprising two brassicaceous host plant species, Brassica nigra or Raphanus sativus, and two aphid species Brevicoryne brassicae or Myzus persicae. These parasitoids were tested in a Y‐tube olfactometer and given the choice between volatiles emitted by an aphid‐infested plant (25 or 100 aphids per plant) and an uninfested control plant. The parasitoid's responses were compared when offered: (i) the same plant–aphid combination as the one on which it had been reared; (ii) the same host plant infested with the alternative aphid species; or (iii) an alternative plant with the alternative aphid species. 4. Aphid density did affect the behavioural responses to the various odour sources, but rearing history did not. Diaeretiella rapae only preferred aphid‐induced to non‐induced plant volatiles at low aphid infestation level, whereas they did not discriminate between volatiles at high aphid infestation level. 5. It is concluded that aphid‐induced volatiles of brassicaceous plants play an important role during host habitat location, but seem less important for parasitoids to locate the aphid host itself. The data are discussed in the light of manipulation of host plant defences by aphids.     

NPC 15437 interacts with the C1 domain of protein kinase C. An analysis using mutant PKC constructs

We recently demonstrated that 2,6,diamino-N-[( 1-(oxotridecyl)-2-piperidinyl]methyl)-hexanamide (NPC 15437) is a selective inhibitor of PKC interacting at the regulatory domain of the enzyme. To further investigate the interaction of NPC 15437 with PKC we expressed a series of cDNAs encoding mutant PKC molecules in COS7 cells. NPC 15437 had no effect on the protein kinase activity of mutants lacking the N-terminal region of the C1 domain. Further, NPC 15437 was a competitive inhibitor of the activation of PKC alpha by phorbol ester and attenuated the binding of phorbol ester to the enzyme in intact cells. The present study demonstrates that mutant enzyme constructs can be used to localize the site of interaction of NPC 15437 with PKC to residues 12-42, which encodes the pseudosubstrate binding domain and part of the first cysteine-rich repeat sequence.     

In vivo hprt mutant frequencies in T-cells of normal human newborns

Mutation at the hypoxanthine-guanine phosphoribosyl transferase locus (hprt; HPRT enzyme) in the human fetus was studied by clonal assay of placental cord blood samples from full-term newborns. Conditions for determining hprt mutant frequencies, as defined for adults, were also optimal for studies in newborns. The mean mutant frequency for 45 normal human newborns (37 male, 8 female) was 0.64 X 10(-6) (SD = 0.41 X 10(-6); median value = 0.58 X 10(-6). These values are approx. 10-fold lower than corresponding adult hprt mutant frequency values. Factors such as limiting-dilution cloning efficiencies, delay prior to study of sample, sex, cryopreservation or technician performing the assay did not significantly affect assay results. Maternal smoking did not result in elevated mutant frequency values. Most wild-type and mutant clones studied were CD4 surface antigen positive (helper/inducer). All hprt mutants analyzed lacked HPRT activity.     

Cloning of a 16-kDa ubiquitin carrier protein from wheat and Arabidopsis thaliana. Identification of functional domains by in vitro mutagenesis.

Ubiquitin carrier proteins (E2s) are involved in the covalent attachment of ubiquitin to a variety of cellular target proteins in eukaryotes. Here, we report the cloning of genes from wheat and Arabidopsis thaliana that encode 16-kDa E2s and a domain analysis of E2s by in vitro mutagenesis. The genes for E216kDa, which we have designated wheat and At UBC1, encode proteins that are only 33% identical (58% similar) with a 23-kDa E2 from wheat (encoded by the gene now designated wheat UBC4), but are 63% identical (82% similar) with the E2 encoded by the Saccharomyces cerevisiae DNA repair gene, RAD6. Unlike the proteins encoded by RAD6 and wheat UBC4, the UBC1 gene products lack acidic C-terminal domains extending beyond the conserved core of the proteins and are incapable of efficient in vitro ligation of ubiquitin to histones. From enzymatic analysis of the UBC1 and UBC4 gene products mutagenized in vitro, we have identified several domains important for E2 function, including the active site cysteine and N-terminal and C-terminal domains. Cysteine residues 88 and 85 in the UBC1 and UBC4 gene products, respectively, are necessary for formation of the ubiquitin-E2 thiol ester intermediate. Whereas the UBC1 gene product does not require its additional cysteine residue at position 116 for thiol ester formation, alteration of cysteine 143 in the UBC4 gene product greatly diminishes this ability. The N terminus of UBC1 contains two domains that affect activity: a proximal region containing hydroxylated and uncharged residues whose removal increases the rate of thiol ester formation and a distal tract rich in basic residues. Deletion or substitution of these basic residues with neutral residues diminishes the rate of thiol ester formation. We have demonstrated also that C-terminal extensions can function to confer substrate specificity to E2s. When the acidic extension was deleted from UBC4, the protein was unable to efficiently conjugate ubiquitin to histones in vitro. Furthermore, fusion of the UBC4 acidic extension to the C terminus of UBC1 resulted in a chimeric protein capable of efficient histone conjugation, as did fusion of short tracts of alternating aspartate and glutamate residues. This result suggests that the target protein specificity of E2s can be altered by the addition of appropriate C-terminal extensions, thus providing a way to modify the selectivity of the ubiquitin system.