Molecular cloning of three cDNAs encoding aminopeptidases from the midgut of Helicoverpa punctigera, the Australian native budworm.

Three cDNAs encoding aminopeptidases HpAPN1, HpAPN2 and HpAPN3, were isolated from a 5th instar larval midgut cDNA library from Helicoverpa punctigera, the Australian native budworm. The sequences recovered contain open reading frames encoding proteins of 1011, 952, and 1013 amino acids, respectively. All three proteins share the consensus zinc binding/gluzincin motif HEXXHX(18)E and the sequence GAMEN common to gluzincin aminopeptidases. Furthermore, signal peptide sequences and C-terminal hydrophobic regions preceded by three small amino acids qualifying for cleavage and GPI anchor attachment are present in all three protein sequences. Northern blotting results indicate differences in the levels of expression and developmental regulation of all three aminopeptidases. HpAPN1, HpAPN2, and HpAPN3 are more closely related to APNs from other lepidopterans than they are to each other. This report of three different aminopeptidases N in Helicoverpa punctigera adds support to a recent suggestion that at least one gene duplication has taken place in ancestral lepidopterans. The full sequences of the aminopeptidases are available at GENBANK with the following accession numbers: HpAPN1: AF217248, HpAPN2: AF217249, HpAPN3: AF217250.     

Incidental Findings on Brain MR Imaging in Older Community-Dwelling Subjects Are Common but Serious Medical Consequences Are Rare: A Cohort Study

Objectives

Incidental findings in neuroimaging occur in 3% of volunteers. Most data come from young subjects. Data on their occurrence in older subjects and their medical, lifestyle and financial consequences are lacking. We determined the prevalence and medical consequences of incidental findings found in community-dwelling older subjects on brain magnetic resonance imaging.

Design

Prospective cohort observational study.

Setting

Single centre study with input from secondary care.

Participants

Lothian Birth Cohort 1936, a study of cognitive ageing.

Main Outcome Measures

Incidental findings identified by two consultant neuroradiologists on structural brain magnetic resonance imaging at age 73 years; resulting medical referrals and interventions.

Primary and Secondary Outcome Measures

Prevalence of incidental findings by individual categories: neoplasms, cysts, vascular lesions, developmental, ear, nose or throat anomalies, by intra- and extracranial location; visual rating of white matter hyperintensities and brain atrophy.

Results

There were 281 incidental findings in 223 (32%) of 700 subjects, including 14 intra- or extracranial neoplasms (2%), 15 intracranial vascular anomalies (2%), and 137 infarcts or haemorrhages (20%). Additionally, 153 had moderate/severe deep white matter hyperintensities (22%) and 176 had cerebral atrophy at, or above, the upper limit of normal (25%) compared with a normative population template. The incidental findings were unrelated to white matter hyperintensities or atrophy; about a third of subjects had both incidental findings and moderate or severe WMH and a quarter had incidental findings and atrophy. The incidental findings resulted in one urgent and nine non-urgent referrals for further medical assessment, but ultimately in no new treatments.

Conclusions

In community-dwelling older subjects, incidental findings, including white matter hyperintensities and atrophy, were common. However, many findings were not of medical importance and, in this age group, most did not result in further assessment and none in change of treatment.     

Palatability and efficacy to possums and rats of pest control baits containing bird repellents

Repellents used to reduce by-kill of birds during pest control must not compromise acceptance by target species. Two repellents combined, anthraquinone (AQ; 0.4 g kg^?1) and d-pulegone (DP; 1.0) did not reduce the palatability of blue-coloured carrot baits to laboratory rats (Rattus norvegicus); nor did DP (2.0). Green-coloured carrot baits coated with AQ, DP or AQ + DP were taken from bait stations by wild possums (Trichosurus vulpecula) and rats. Toxic (1080) bait coated with AQ (0.4) and peanut oil (0.1) had reduced palatability but was accepted by laboratory rats. However, laboratory rats did not consume enough baits coated with AQ and bacon, peanut butter, cinnamon or DP to be killed. Anthraquinone (0.4 or 0.8) plus cinnamon and DP (0.5) did not affect palatability or lethality to captive ship rats (R. rattus) or possums. Anthraquinone and DP as surface coatings on baits are therefore acceptable to possums and possibly rats, at concentrations that deter some bird species.     

Adult neurogenesis and cell cycle regulation in the crustacean olfactory pathway: from glial precursors to differentiated neurons

Adult neurogenesis is a characteristic feature of the olfactory pathways of decapod crustaceans. In crayfish and clawed lobsters, adult-born neurons are the progeny of precursor cells with glial characteristics located in a neurogenic niche on the ventral surface of the brain. The daughters of these precursor cells migrate during S and G₂ stages of the cell cycle along glial fibers to lateral (cluster 10) and medial (cluster 9) proliferation zones. Here, they divide (M phase) producing offspring that differentiate into olfactory interneurons. The complete lineage of cells producing neurons in these animals, therefore, is arranged along the migratory stream according to cell cycle stage. We have exploited this model to examine the influence of environmental and endogenous factors on adult neurogenesis. We find that increased levels of serotonin upregulate neuronal production, as does maintaining animals in an enriched (versus deprived) environment or augmenting their diet with omega-3 fatty acids; increased levels of nitric oxide, on the other hand, decrease the rate of neurogenesis. The features of the neurogenic niche and migratory streams, and the fact that these continue to function in vitro, provide opportunities unavailable in other organisms to explore the sequence of cellular and molecular events leading to the production of new neurons in adult brains.     

混合线性模型下猪群间遗传联系的度量

采用关联指数（IC）和决定系数（CD）两种方法,度量混合线性模型遗传评估下猪群体间的遗传关联性。结果表明,加拿大安大略省的大约克夏猪、长白猪、杜洛克猪和汉普夏猪4个主要品种群体间具有良好的遗传联系。CD法既组合了数据结构和信息量,又考虑了预测误差方差和遗传变异性,是一个选择判断遗传评估精度的好方法。     

Characterization of proteolytic and collagenolytic enzymes from the larvae of Lucilia cuprina, the sheep blowfly

Isoelectric focusing was used to characterize proteolytic enzymes in homogenate and excretory-secretory preparations of the larvae of L. cuprina, the sheep blowfly. Zymogram overlays showed that the larvae produce a number of highly active proteases which have a wide range of isoelectric points and molecular weights. The alkaline and neutral pI proteases were inhibited by phenylmethyl-sulfonylfluoride, leupeptin and aprotinin; this indicated the presence of serine in the active site. Pepstatin and the metal chelating agent ethylenediaminetetraacetic acid had no effect on the activity of any of the proteases. Optimal pH for activity of the proteases was between 7 and 8. In addition, the proteases were found to be heat labile. Digestion of collagen fibrils confirmed the existence of collagenolytic activity in the excretory-secretory enzyme preparations. It is suggested that these enzymes may be involved in the nutrition of the larvae and in the pathogenesis of the lesion on the skin.     

A requirement for trypsin-sensitive cell-surface components for cell-cell interactions of embryonic neural retina cells

A quantitative assay was used to measure the rate of collection of a population of embryonic neural retina cells to the surface of cell aggregates. The rate of collection of freshly trysinized cells was limited in the initial stages by the rate of replacement of trypsin-sensitive cell- surface components. When cells were preincubated, or "recovered," and then added to cell aggregates, collection occurred at a linear rate and was independent of protein and glycoprotein synthesis. The adhesion of recovered cells was temperature and energy dependent, and was reversibly inhibited by cytochalasin B. Colchicine had little effect on collection of recovered cells. Antiserum directed against recovered cell membranes was shown to bind to recovered cells by indirect immunofluorescence. The antiserum also was shown to inhibit collection of recovered cells to aggregates, suggesting that at least some of the antigens identified might be involved in the adhesion process. The inhibitory effect of the antiserum was dose dependent . Freshly trypsinized cells absorbed neither the immunofluorescence activity nor the adhesion-inhibiting activity. Recovered cells absorbed away both activities. In specificity studies, dorsal neural retina cells adhered to aggregates of ventral optic tectum in preference to aggregates of dorsal optic tectum. The adhesive specificity of the dorsal retina cells was less sensitive to trypsin than the adhesive specificity of ventral retina cells which adhered preferentially to dorsal tectal aggregates only after a period of recovery.     

Fasciola hepatica: some properties of a precipitate which forms when metacercariae are cultured in immune rat serum.

When Fasciola hepatica metacercariae are cultured in immune rat serum a precipitate forms on their teguments which is a complex of parasite metabolic antigen and rat immunoglobulin, possibly IgG. Continuous secretion of the antigen by the parasite and its precipitation with antibody leads to the eventual appearance of precipitate in the culture medium. Ouchterlony double diffusion tests indicate that only one antigen/antibody interaction appears to be involved in precipitate formation. When rats were vaccinated with precipitate emulsified with Freund's complete adjuvant then given an oral challenge with metacercariae, there was a reduction of as much as 50% in their worm burdens compared with controls. This evidence suggests that the precipitate contains a functional antigen of the parasite. The rat immunoglobulin component is therefore presumed to be protective antibody.     

Characterization of sheep antibodies involved in precipitate formation with surface antigens of Fasciola hepatica in vitro

Sandeman R. M. and Howell M. J. 1982. Characterization of sheep antibodies involved in precipitate formation with surface antigens of Fasciola hepatica in vitro. International Journal for Parasitology12: 467–471. The role of sheep antibodies which precipitate with surface antigens of Fasciola hepatica is unclear. In an attempt to clarify their function these antibodies were characterized as to their immunoglobulin class and ability to affect the survival of fluke in rats. The ability of fluke antigens complexed with sheep antibody to vaccinate rats against infection was also tested. IgM antibodies were involved in precipitate formation on the teguments of fluke 3 weeks after infection but IgG₁ predominated at later stages of infection. The decreased survival of fluke in rats after culture with increasing levels of sheep antibodies suggests that the antibodies exert some deleterious effect on the fluke in vitro. The fluke antigen-sheep antibody complex failed to immunize rats against infection. Since sheep antibodies to F. hepatica can impair the ability of fluke to resist further attack in rats but not sheep, it is suggested that some effector mechanism other than antibody is defective in the latter.