Chemoreception of an oviposition deterrent associated with eggs in pieris brassicae

Electro-antennograms (EAG) in Pieris brassicae butterflies showed graded responses to the odour of intact conspecific eggs, and also to leaf and flower volatiles. Contributing to this summated potential are at least two types of sensilla on each segment of the antenna, although the terminal 6–8 segments do not respond proportionately. Analysis of the activity profiles of single olfactory cells to these compounds shows a typical generalist spectrum, with 0–3 cells per sensillum responding to the stimulus by an increase or decrease in spike frequency. The pheromone associated with eggs and deterring other females from ovipositing is not present in ovaries, but is produced in the accessory glands. It is water-soluble, has a low volatility and causes an increase in spike frequency in tarsal contact chemoreceptors.Behavioural evidence for the presence of a three-tier discrimination (visual detection of eggs or larvae: olfactory detection of aversion pheromone during fluttering over the leaves: contact discrimination by tarsae after landing (Rothschild & Schoonhoven, 1977)) is supported by electrophysiological results, which indicate the involvement of olfactory and contact chemoreceptors in recognising the presence of eggs.

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Zusammenfassung Elektroantennogramme (EAG) von Pieris brassicae Faltern zeigten abgestufte Reaktionen auf den Geruch konspezifischer Eier und auch auf flüchtige Stoffe von Blättern und Blumen. Zu diesem summierten Potential tragen mindestens zwei Typen von Sensillen auf jedem Segment der Fühler bei, wobei allerdings die 6–8 Endglieder nicht proportional reagieren. Die Aktivitätsprofile einzelner Geruchszellen entsprechen einem typischen Spektrum eines generalist. 0–3 Zellen pro Sensille reagieren auf die Reizung mit erhöhter oder erniedrigter Impulsfrequenz. Die Markierung der Eier, welche andere Weibchen von der Eiablage abhält, ist in den Ovarien nicht vorhanden, wird jedoch in den akzessorischen Drüsen erzeugt. Sie ist wasserlöslich, hat eine geringe Flüchtigkeit und verursacht eine erhöhte Impulsfrequenz bei Kontaktrezeptoren der Tarsen.

     

Selective inhibition of prostaglandin biosynthesis by gold salts and phenylbutazone

Gold salts and phenylbutazone selectively inhibit the synthesis of PGF_2α and PGE₂ respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE₂ and PGF_2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function.     

Two silicone nontoxic fouling release coatings: Hydrosilation cured PDMS and CaCO3 filled,ethoxysiloxane cured RTV11

Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11^?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm^‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm^‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented.     

Inhibition of ADP-induced intracellular Ca2+ responses and platelet aggregation by the P2Y12 receptor antagonists AR-C69931MX and clopidogrel is enhanced by prostaglandin E1

P2Y(12) antagonists such as clopidogrel and AR-C69931MX inhibit aggregation by antagonizing the effects of ADP at P2Y(12) receptors on platelets. Agents such as PGE(1) also inhibit aggregation by stimulating adenylate cyclase to produce cAMP, which interferes with Ca(2+) mobilization within the cell. Since one facet of P2Y(12) receptors is that they mediate inhibition of adenylate cyclase by ADP, it might be expected that P2Y(12) antagonists would interact with PGE(1). We have explored the effects of PGE(1) and AR-C69931MX singly and in combination on ADP-induced intracellular Ca(2+) ([Ca(2+)](i)) responses and aggregation. PGE(1) alone caused parallel dose-dependent inhibition of [Ca(2+)](i) and aggregation responses. AR-C66931MX alone caused only partial inhibition of [Ca(2+)](i) despite a marked inhibitory effect on aggregation. Combinations of PGE(1) with AR-C66931MX were found to act in synergy to reduce both [Ca(2+)](i) and aggregation. This effect was confirmed in patients with acute coronary syndromes by studying the inhibitory effects of PGE(1) on [Ca(2+)](i) and aggregation before and after clopidogrel. In summary, we have shown that P2Y(12) antagonists interact with natural agents such as PGE(1) to provide more effective inhibition of [Ca(2+)](i) and platelet aggregation. This would contribute to the effectiveness of P2Y(12) antagonists as antithrombotic agents in man.     

The aging-associated enzyme CLK-1 is a member of the carboxylate-bridged diiron family of proteins

The aging-associated enzyme CLK-1 is proposed to be a member of the carboxylate-bridged diiron family of proteins. To evaluate this hypothesis and characterize the protein, we expressed soluble mouse CLK-1 (MCLK1) in Escherichia coli as a heterologous host. Using Mo?ssbauer and EPR spectroscopy, we established that MCLK1 indeed belongs to this protein family. Biochemical analyses of the in vitro activity of MCLK1 with quinone substrates revealed that NADH can serve directly as a reductant for catalytic activation of dioxygen and substrate oxidation by the enzyme, with no requirement for an additional reductase protein component. The direct reaction of NADH with a diiron-containing oxidase enzyme has not previously been encountered for any member of the protein superfamily.     

A field investigation of intra-cervical insemination with reduced sperm numbers in gilts

A novel insemination catheter with a smaller polyurethane tip for deeper insertion into the cervix of gilts was compared with the conventional catheter. The novel catheter could be inserted 31.4 mm deeper than the conventional catheter into the gilt cervix, but the difference diminished with parity until the sixth parity when there was no difference in penetration depth between the catheters. In Experiment 1, cyclic gilts were inseminated upon display of oestrus (back pressure test) in the presence of a boar (0 h) and 24 h later. The control group (n = 300) were inseminated with 2 x 10(9) total spermatozoa and the treatment group (n = 300) with 1 x 10(9) total spermatozoa per inseminate, in both cases utilising the novel insemination catheter. No significant differences were observed for farrowing rate and litter size, the values of which were those expected for natural mating. In Experiment 2, 66 cyclic gilts were subjected to the same heat detection and service regime as for Experiment 1 but were served with <1 x 10(9) total sperm cells per inseminate using the new device. Conception rates and embryo counts were recorded. Conception rate declined with <500 x 10(6) spermatozoa, and number of embryos (a reflection of potential litter size) was significantly reduced. Use of the new catheter for gilts with 1 x 10(9) total sperm cells per inseminate will achieve commercially acceptable fertility and fecundity levels, and offer substantial commercial benefits with more rapid genetic gains.     

Investigating the effects of dietary folic acid on sperm count, DNA damage and mutation in Balb/c mice

The cytokinesis-block micronucleus cytome (CBMN-Cyt) assay was originally developed as an ideal system for measuring DNA damage, cytostasis and cytotoxicity. The objective of the present study is to simultaneously evaluate the background levels of micronuclei (MN), nucleoplasmic bridges (NPBs), nuclear buds (NBUDs), cell death (necrosis or apoptosis) and nuclear division index (NDI) in the peripheral blood lymphocytes of non-occupationally exposed, healthy subjects living in the city of Kayseri in Turkey. We used the CBMN-Cyt assay, taking into account factors - age, gender, and smoking habits - that might affect MN frequency and also other CBMN-Cyt assay parameters. Ninety-six healthy subjects (48 female and 48 male) were selected with ages varying between 21 and 60 years. The parameters, except for the number of binucleated (BN) cells with NPBs, showed no statistically significant difference between smokers and non-smokers. There were significant differences between female and male groups in MN frequency (higher in females) and in the number of NPBs (lower in females), while the other parameters were not significantly different between genders. The correlations between years of age and MN frequency, number of NPBs and the frequency of necrotic cells were statistically significant, while the correlations between the years of age and the other parameters were not. The results of the correlation analysis between years of smoking and MN frequency were positive, although no statistically significant correlation was found between the years of smoking and the other parameters. Among the smokers, no correlation was found either between the pack-years of smoking and the parameters assessed in this group. The results of the present study provide evidence of increasing MN frequency, number of NPBs and frequency of necrotic cells with increasing age in the peripheral blood lymphocytes of healthy individuals and influencing MN frequency and number of NPBs by gender.     

Spatial and Temporal Analysis of Contact Rates in Female White-Tailed Deer

Abstract: White-tailed deer (Odocoileus virginianus) are important game mammals and potential reservoirs of diseases of domestic livestock; thus, diseases of deer are of great concern to wildlife managers. Contact, either direct or indirect, is necessary for disease transmission, but we know little about the ecological contexts that promote intrasexual contact among deer. Using pair-wise direct contacts estimated from Global Positioning System collar locations and joint utilization distributions (JUDs), we assessed habitats in which contacts occur to test whether direct contact rates among female white-tailed deer in different social groups differs among land-cover types. We also tested whether contact rates differed among seasons, lunar phases, and times of day. We obtained locations from 27 female deer for periods of 0.5–17 months during 2002–2006. We designated any simultaneous pair of locations for 2 deer <25 m apart as a direct contact. For each season, we used compositional analysis to compare land-cover types where 2 deer had contact to available land-cover weighted by their JUD. We used mixed-model logistic regression to test for effects of season, lunar phase, and time of day on contact rates. Contact rates during the gestation season were greater than expected from random use in forest and grassland cover, whereas contact rates during the fawning period were greater in agricultural fields than in other land-cover types. Contact rates were greatest during the rut and lowest in summer. Diel patterns of contact rates varied with season, and contact rates were elevated during full moon compared to other lunar periods. Both spatial and temporal analyses suggest that contact between female deer in different social groups occurs mainly during feeding, which highlights the potential impact of food distribution and habitat on contact rates among deer. By using methods to associate contacts and land-cover, we have created beneficial tools for more elaborate and detailed studies of disease transmission. Our methods can offer information necessary to develop spatially realistic models of disease transmission in deer.     

Immunological studies in pre-eclamptic toxaemia.

Although five patients with severe pre-eclamptic toxaemia (PET) had increased anticomplementary activity in their serum, there was no evidence of complement activation in the plasma of four of the five patients. These results are not implicated in the pathogenesis of PET. No significant correlation was found between anticomplementary activity and pregnancy-associated alpha2-glycoprotein.     

The recent evolution of a pseudogene: diversity and divergence of a mitochondria-localized small heat shock protein in Arabidopsis thaliana

In this study we examined the evolution of the genes for three organelle-localized small heat shock proteins in Arabidopsis thaliana: the chloroplast-localized (CP) protein HSP21 and two mitochondria-localized (MT) proteins, HSP23.5 and HSP23.6. We found that the CP protein and one of the MT proteins, HSP23.6, are evolving under purifying selection to maintain function. In contrast, the gene for HSP23.5, the other MT protein, is highly variable within A. thaliana, and in some accessions or ecotypes this gene may be a pseudogene. HSP23.5 and HSP23.6 are related via a segmental duplication event, and the presence of orthologs of each gene in other species within the Brassicaceae indicates that the duplication generating HSP23.5 and HSP23.6 may have occurred as much as 20 million years ago. This is considerably longer than the 4 million year half-life of gene duplicates (functional genes as well as pseudogenes) reported by some studies. Our results are consistent with the prediction that after gene duplication one gene duplicate can be maintained for some time under relaxed selection while it accumulates random mutations. By capturing a pseudogene in the making our study provides important information on how pseudogenes are formed.