Population dynamics of soybean aphid and biotic mortality at the edge of its range

The soybean aphid, Aphis glycines Matsumura, was introduced to north central North America from Asia in 2000, and it has become a major pest of soybean, Glycine max (L.) Merr. Understanding how natural enemies impact aphid populations in the field is an important component in developing a comprehensive management plan. We examined the impact of naturally occurring predators in the field by using exclusion cages during July-August 2004 and 2005. Field cages of different mesh diameters were used to exclude different sizes of natural enemies from aphid-infested plots. Plots were surveyed twice weekly for A. glycines and natural enemies. Densities were recorded. Cage effects on mean temperature and soybean growth were found to be insignificant. Significant differences in aphid density were found between treatments in both years of the study (2004 and 2005); however, aphid densities between years were highly variable. Orius insidiosus (Say) was the most commonly occurring predator in the field. Other natural enemies were present in both years but not in high numbers. Parasitoids were present in both years, but their numbers did not suppress aphid densities. Treatment differences within years were related to the abundance of natural enemies. The large differences in aphid abundance between years were associated with the higher number of O. insidiosus found in the field in 2005 (416 total O. insidiosus) than in 2004 (149 total O. insidiosus). This study suggests that naturally occurring predators, primarily O. insidiosus, can have a large impact on A. glycines populations when predator populations are established before initial A. glycines colonization.     

White Matter Tract Damage in the Behavioral Variant of Frontotemporal and Corticobasal Dementia Syndromes

The phenotypes of the behavioral variant of frontotemporal dementia and the corticobasal syndrome present considerable clinical and anatomical overlap. The respective patterns of white matter damage in these syndromes have not been directly contrasted. Beyond cortical involvement, damage to white matter pathways may critically contribute to both common and specific symptoms in both conditions. Here we assessed patients with the behavioral variant of frontotemporal dementia and corticobasal syndrome with whole-brain diffusion tensor imaging to identify the white matter networks underlying these pathologies. Twenty patients with the behavioral variant of frontotemporal dementia, 19 with corticobasal syndrome, and 15 healthy controls were enrolled in the study. Differences in tract integrity between (i) patients and controls, and (ii) patients with the corticobasal syndrome and the behavioral variant of frontotemporal dementia were assessed with whole brain tract-based spatial statistics and analyses of regions of interest. Behavioral variant of frontotemporal dementia and the corticobasal syndrome shared a pattern of bilaterally decreased white matter integrity in the anterior commissure, genu and body of the corpus callosum, corona radiata and in the long intrahemispheric association pathways. Patients with the behavioral variant of frontotemporal dementia showed greater damage to the uncinate fasciculus, genu of corpus callosum and forceps minor. In contrast, corticobasal syndrome patients had greater damage to the midbody of the corpus callosum and perirolandic corona radiata. Whereas several compact white matter pathways were damaged in both the behavioral variant of frontotemporal dementia and corticobasal syndrome, the distribution and degree of white matter damage differed between them. These findings concur with the distinctive clinical manifestations of these conditions and may improve the in vivo neuroanatomical and diagnostic characterization of these disorders.     

In vitro antigen ELISA for quality control of tetanus vaccines

Consistency of production is recognised as an important aspect of vaccine manufacture and suitably validated in vitro assays are required for quality control testing of these products. For the manufacture and batch release of tetanus vaccines, antigen content and integrity, and degree of adsorption of antigen to the adjuvant are critical parameters that should be monitored for consistency. Here we describe the development and use of an Enzyme Linked Immunosorbent Assay (ELISA) to quantify tetanus antigen in combined vaccine products and to measure the degree of adsorption of antigen to adjuvant. Whilst the antigen assay cannot be assumed to predict potency for different products, it can be used as part of a panel of in vitro methods to provide a more informative product profile and to monitor trends in production. The antigen assay is particularly valuable for providing quantitative information on every final lot when modifications of in vivo potency tests, such as single dilution assays, are used.     

Checklist of the Caesalpinioideae (Leguminosae) of Equatorial Guinea (Annobón, Bioko and Río Muni)

This study provides a checklist of the Caesalpinioideae (Leguminosae) present in Equatorial Guinea, comprising 52 genera and 124 taxa. Seven species are known from Annobón, 33 from Bioko and 109 from Río Muni. The best represented genus is Senna with eight species. In addition, bibliographic references for Caesalpinioideae (Leguminosae) from Equatorial Guinea have been gathered and checked. Fourteen species are included based on literature records, because their distribution ranges suggest they may occur in Equatorial Guinea, 11 introduced species could be naturalized, and 45 taxa are recorded for the first time from the country. This represents an increase of over 35% in the floristic knowledge of Caesalpinioideae from Equatorial Guinea. A statistical summary is presented at the end of the checklist.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 541–562.     

Isolation and characterization of a large,neurite-associated glycoconjugate from neuroblastoma cells

A high molecular weight glycoconjugate has been isolated from neurite-producing neuronal tumor cells in culture and has been designated as I(0) based on its elution characteristics in gel filtration chromatography. This molecule cannot be found in a variety of nonneuronal cells. I(0) is found in the substratum-attached material or cell fraction of neurite-producing neuroblastoma cells, depending upon culture conditions. It is found in the substratum-bound fraction of B104 rat neuroblastoma cells during serum starvation and in the EGTA-detached cell fraction of B104 cells grown in chemically defined N2 medium. It occurs only in the cell fraction of the human neuroblastoma line Platt. Examination of behavioral variants of the B104 rat line further strengthens the association of I(0) with neurite production; the constitutive neurite-producing E(R)B9 variant contains I(0) while the non-neurite-producing E(R)A11 variant does not. I(0) is large, eluting in the void volume of sepharose-CL2B columns. Radioiodination of intact cells with lactoperoxidase shows I(0) to be a cell surface component. Metabolic radiolabeling studies show that it contains a high proportion of polysaccharide to protein, does not contain mannose, and is unsulfated. Alkaline borohydride reduction release two size classes of large polysaccharide chain. The alkaline reduction results, along with the mannose incorporation studies, show the presence of O-glycosidic linkages and few, if any, N-linkages. Resistance to nitrous acid deamination, insensitivity to glycosaminoglycan lyases, and the absence of sulfation, indicate that I(0) does not contain the glycosaminoglycans hyaluronic acid, chondroitin-, dermatan-, or heparin- sulfates. Affinity column chromatography reveals high binding affinity of I(0) to polyornithine and no binding to gelatin (collagen) or the glycosaminoglycans hyaluronate and heparin. These studies describe a unique high molecular weight glycoconjugate on the surface of neurite-producing neuroblastoma cell lines from two species.     

Deep-level diagnostic value of the rDNA-ITS region

The similarity of certain reported angiosperm rDNA internal transcribed spacer (ITS) region sequences to those of green algae prompted our analysis of the deep-level phylogenetic signal in the highly conserved but short 5.8S and hypervariable ITS2 sequences. We found that 5.8S sequences yield phylogenetic trees similar to but less well supported than those generated by a ca. 10-fold longer alignment from rDNA-18S sequences, as well as independent evidence. We attribute this result to our finding that, compared to 18S, the 5.8S has a higher proportion of sites subject to vary and greater among-site substitution rate homogeneity. We also determined that our phylogenetic results are not likely affected by intramolecular compensatory mutation to maintain RNA secondary structure nor by evident systematic biases in base composition. Despite historical homology, there appears to be no ITS2 primary sequence similarity shared sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that groups, however, share sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that ITS region sequences can diagnose organismal origins and phylogenetic relationships at many phylogenetic levels and provide a useful paradigm for molecular evolutionary study.