Comment on "Divergent induced responses to an invasive predator in marine mussel populations"

Freeman and Byers (Reports, 11 August 2006, p. 831) presented evidence for the rapid evolution of antipredator defenses in the mussel Mytilus edulis. However, their analysis is confounded by three issues. Samples from some sites are likely to have included a second species, M. trossulus; their manipulation of chemical cues does not preclude other interpretations; and they failed to establish an adaptive significance to shell thickening.     

Blocking ELISA to distinguish pseudorabies virus-infected pigs from those vaccinated with a glycoprotein gIII deletion mutant

A blocking enzyme-linked immunosorbent assay (ELISA) test has been developed to distinguish pseudorabies virus (PRV)-infected pigs from those immunized with a glycoprotein g92(gIII) deletion mutant, PRV(dlg92dltk). The blocking ELISA utilizes 96-well microtiter test plates coated with a cloned PRV g92(gIII) antigen, a mouse monoclonal antibody against gIII antigen (moMCAgIII): horseradish peroxidase (HRPO) conjugate, and undiluted test sera. Analyses can be completed in less than 3 hours with results printed out by an automated plate reader. Analyses on over 300 pig sera from PRV-free farms, on sera from other species, and on control sera containing antibodies to microorganisms other than PRV showed that the ratio of the optical density at 405 nm for the test sample to the optical density at 405 nm for the negative control (S/N value) was greater than 0.7 for all sera. No false positives were identified. Likewise, the S/N values were greater than 0.7 for over 400 sera obtained from pigs vaccinated twice with more than 1,000 times the standard PRV (dlg92dltk) dose or 1-4 times with the standard dose (2 x 10(5) TCID50/pig). Following challenge exposure to virulent PRV, the S/N values of the vaccinates were 0.1, showing that g92(gIII) antibodies in the sera of experimentally challenged pigs strongly blocked the binding of the moMCAgIII:HRPO conjugate to the antigen-coated wells. Sera of 233 pigs from PRV-infected herds with virus neutralization (VN) titers of 1:4 or greater were tested. All except 2 of these sera had S/N values less than 0.7 and more than 175 had S/N values less than 0.1. Sixteen sera from fetal pigs with VN titers of 1:4 or greater had S/N values of 0.24 or less, but 2 sera with VN titers of 1:4 when tested 5 years prior to the PRV g92(gIII) blocking ELISA test gave false negative S/N values. Twenty-four of 29 pig sera from PRV-infected herds with VN titers less than 1:4 were positive for g92(gIII) antibodies, illustrating the sensitivity of the PRV g92(gIII) blocking ELISA test. Analyses on 7 sera with VN titers of 1:4-1:64 showed that titers obtained with the PRV g92(gIII) blocking ELISA test were from 2- to 16-fold greater than the VN titers. The accuracy and sensitivity of the PRV g92(gIII) blocking ELISA test was further demonstrated by analyses of 40 unknown sera supplied in the National Veterinary Services Laboratories 1988 PRV check test kit.     

Forensic DNA profiling of tropical timber species in Peninsular Malaysia

Illegal logging poses a significant threat to the sustainability of tropical forest ecosystems. By using Neobalanocarpus heimii (Dipterocarpaceae) as an example, the study assessed the feasibility of using short tandem repeats (STRs) as a tool to identify the source of illegally logged timber. Thirty natural populations of N. heimii were profiled using 12 STRs to develop the DNA profiling databases. As the cluster analysis divided the 30 populations into three genetic clusters, corresponding to three subregions within Peninsular Malaysia. The DNA databases were characterised at the levels of population, subregion and Peninsular Malaysia. Independence tests within and among loci were violated in all the databases due to significant levels of population differentiation and inbreeding. Thus, the effects of population substructure and inbreeding should be incorporated into the calculation of random match probability. The random match probabilities estimated using subpopulation and subpopulation-cum-inbreeding models were biased in favour of the defendant, whereas the random match probabilities estimated using product rule were biased in favour of the prosecutor. The conservativeness tests showed that the subregion and Peninsular Malaysia databases were conservative, and these databases should be able to provide legal evidence for court proceedings against illegal loggers in Peninsular Malaysia.     

Bioactivity-guided fractionation of the lipoxygenase and cyclooxygenase inhibiting constituents from Chisocheton polyandrus Merr

Lipoxygenase (LOX)-inhibiting compounds from the leaves of Chisocheton polyandrus Merr. were isolated in this study using a bioactivity-guided fractionation technique. Two dammarane triterpenoids, dammara-20,24-dien-3-one (1) (IC(50)=0.69±0.07 μM) and 24-hydroxydammara-20,25-dien-3-one (2) (IC(50)=1.11±0.38 μM), were isolated and identified based on the soybean LOX assay. Dammara-20,24-dien-3-one (1) exhibited dual inhibition of both human 5-LOX (IC(50)=24.27±2.92 μM) and cyclooxygenase-2 (COX-2) (IC(50)=3.17±0.90 μM), whereas 24-hydroxydammara-20,25-dien-3-one (2) did not exhibit any significant inhibitory effects. This report is the first to detail the inhibition of LOX and COX by both C. polyandrus and its isolated compounds.     

The cost of Border disease infection in a commercial flock

The performance of a flock of 203 crossbred ewes on a lowland farm was examined. Before lambing the ewes were run in two groups (A and B). Group A (124 ewes) produced significantly fewer marketable lambs as a consequence of neonatal and later losses. The associated clinical features were consistent with Border disease infection and the presence of the virus was demonstrated. These features were not evident in the progeny of group B (79 ewes). The market sale returns of both groups of sheep were compared and the flock performance was contrasted with that of the two previous years. The outbreak of Border disease resulted in a potential reduction of income in excess of 20 per cent. Such a loss supports the necessity for an effective control strategy for Border disease.     

Control of their environment reduces emotionality in rats

Rats reared from birth in a "contingent environment" in which they controlled lighting conditions and the delivery of food and water were compared as adults to rats reared in an environment in which they received the same food, water, and lighting conditions, but without control over their occurrence. Rats reared in the contingent environment were less emotional, as judged by activity and defecation scores in open-field testing.     

Structural Properties of Starch Fractions Isolated from Normal and Mutant Corn Genotypes Using Different Methods

The objectives of this research study were to isolate, evaluate, and compare the fine structures of starch fractions obtained from a wild‐type (normal) corn starch and amylose‐extender25, dull39, sugary2, and sugary1 corn mutants in the same genetic background using three different fractionation procedures based on gel‐permeation chromatography or alcohol‐precipitation methods. Starch fractions obtained from each of the three methods were enzymatically debranched and analyzed using high‐performance anion‐exchange chromatography with a postcolumn amyloglucosidase reactor and a pulsed amperometric detector. The separations were performed by fractionation on a GPC column, by precipitation with 1‐butanol, and by preferential precipitation with 1‐butanol and isoamyl alcohol. Using any of these methods, no apparent differences in the molecular weight distributions of amylopectin or of amylose among the different starches were observed. The proportions of branch chain lengths of the starch components obtained by the various fractionation methods were very similar among methods for each of the starch types analyzed, such as the predominance of long branch chains in ae25 corn and that of the short branch chains in su2 corn. Overall, the effect of the corn mutations was more important to the differences observed among the starch types than was the method of fractionation used.     

Determination of glucosinolates using their alkaline degradation and reaction with ferricyanide.

Glucosinolates, a group of naturally occurring thioglucosides, are significant factors impairing the nutritional quality of rapeseed and postextraction rapeseed meal, restricting its use as high-quality protein animal feed. Currently, the European Community standards and Canola definition are being brought in line recommending cultivation and marketing of rapeseed with a glucosinolate content below 18 micromol of total glucosinolates per gram of seeds. Furthermore, some glucosinolates are of increasing interest in Brassica vegetables due to their proven cancer-preventing activities. A novel approach to the analysis of total glucosinolates is reported in this paper based on their alkaline degradation and subsequent reaction of released 1-thioglucose with ferricyanide. The reaction was followed spectrophotometrically using sinigrin and glucotropeaolin as model glucosinolates. The applicability of the method was demonstrated using rapeseed extracts after reducing the interfering effect of phenolics by their adsorption onto polyvinylpolypyrrolidone. Good agreement with official ISO methods was shown.     

The nature of the 660-kilometer discontinuity in Earth's mantle from global seismic observations of PP precursors

The 660-kilometer discontinuity, which separates Earth's upper and lower mantle, has been detected routinely on a global scale in underside reflections of precursors to SS shear waves. Here, we report observations of this discontinuity in many different regions, using precursors to compressional PP waves. The apparent absence of such precursors in previous studies had posed major problems for models of mantle composition. We find a complicated structure, showing single and double reflections ranging in depth from 640 to 720 kilometers, that requires the existence of multiple phase transitions at the base of the transition zone. The results are consistent with a pyrolite mantle composition.