Gypsy moth parasitoids in the declining outbreak in Lithuania

A 3 year study was conducted on the parasitoids of gypsy moth larvae in two reducing outbreak areas in Lithuania. Overall parasitism of 25.0 ± 2.0% in the first post-culmination year was significantly lower than the 36.3 ± 1.4 and 35.2 ± 1.4% parasitism in the two subsequent years. When analysed in terms of the life stage at which the host was collected, the total parasitism over 3 years was constantly increasing from 3.1 ± 0.8 in the first to 72.5 ± 2.9% in the sixth instar. Parasetigena silvestris R.-D. dominated causing 48.7 ± 1.5% parasitism and 16.7 ± 0.6% larval mortality preferably in late instars. Phobocampe disparis Vier. contributed to 21.9 ± 1.2% parasitism and 7.5 ± 0.5% mortality recovering from early instar larvae. Meteorus pulchricornis Wes. parasitized 4.3 ± 0.6% gypsy moth larvae causing 1.5 ± 0.2% mortality and a few Apanteles species provided 2.8 ± 0.6% parasitism and 1.0 ± 0.2% mortality. The gypsy moth in Lithuania was reported to act as host for Rogas sp. (Hym., Braconidae) and Siphona boreata Mes. (Dipt., Tachinidae).     

Oxidants inhibit ERK/MAPK and prevent its ability to delay neutrophil apoptosis downstream of mitochondrial changes and at the level of XIAP

Normal spontaneous apoptosis in neutrophils is enhanced by "stress" stimuli such as tumor necrosis factor-alpha, Fas ligand, and oxidants, and this effect is inhibited by anti-apoptotic stimuli including granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, and formylmethionine-leucine-phenylalanine. In this report we demonstrate that anti-apoptotic stimuli protect neutrophils from stress-induced apoptosis via activation of the ERK/MAPK pathway. The protection occurs downstream of mitochondrial alterations assessed as a decrease in membrane potential concomitant with enhanced cytochrome c release. ERK activation was shown to inhibit apoptosis by maintaining levels of XIAP, which is normally decreased in the presence of the pro-apoptotic/stress stimuli. This report also demonstrates that potent intra- and extracellular oxidants inhibit the protective effect of ERK. Oxidant-dependent inhibition of ERK was because of activation of p38 MAPK and activation of the protein phosphatases PP1 and PP2A. Our data suggest that ERK suppresses stress-induced apoptosis downstream of mitochondrial alterations by maintaining XIAP levels and that oxidants block this effect through activation of p38 and protein phosphatases.     

The nematode Anisakis simplex in American shad (Alosa sapidissima) in two Oregon rivers

This paper represents the first report of the nematode Anisakis simplex in the American shad (Alosa sapidissima) in its introduced range in the American Pacific Northwest. All the adult shad sampled from spawning populations in the Willamette (n = 9) and Umpqua (n = 12) rivers were infected with A. simplex with intensities ranging from 6 to 89 worms per fish. This preliminary investigation contrasts sharply with previous studies in the native range of American shad and confirms that this fish may be an important intermediate host for A. simplex in the Pacific Northwest. It is suggested that this new parasite-host relationship has led to an ecological expansion into rivers and Anisakis may present an emerging health risk for wildlife and some human consumers.     

A cellular mechanism for prepulse inhibition

In prepulse inhibition (PPI), startle responses to sudden, unexpected stimuli are markedly attenuated if immediately preceded by a weak stimulus of almost any modality. This experimental paradigm exposes a potent inhibitory process, present in nervous systems from invertebrates to humans, that is widely considered to play an important role in reducing distraction during the processing of sensory input. The neural mechanisms mediating PPI are of considerable interest given evidence linking PPI deficits with some of the cognitive disorders of schizophrenia. Here, in the marine mollusk Tritonia diomedea, we describe a detailed cellular mechanism for PPI--a combination of presynaptic inhibition of startle afferent neurons together with distributed postsynaptic inhibition of several downstream interneuronal sites in the startle circuit.     

Ubiquitin hydrolase Uch-L1 rescues beta-amyloid-induced decreases in synaptic function and contextual memory

The neuronal ubiquitin/proteasomal pathway has been implicated in the pathogenesis of Alzheimer's disease (AD). We now show that a component of the pathway, ubiquitin C-terminal hydrolase L1 (Uch-L1), is required for normal synaptic and cognitive function. Transduction of Uch-L1 protein fused to the transduction domain of HIV-transactivator protein (TAT) restores normal enzymatic activity and synaptic function both in hippocampal slices treated with oligomeric Abeta and in the APP/PS1 mouse model of AD. Moreover, intraperitoneal injections with the fusion protein improve the retention of contextual learning in APP/PS1 mice over time. The beneficial effect of the Uch-L1 fusion protein is associated with restoration of normal levels of the PKA-regulatory subunit IIalpha, PKA activity, and CREB phosphorylation.     

Characterization of Hepatitis G Virus (GB-C Virus) Particles: Evidence for a Nucleocapsid and Expression of Sequences Upstream of the E1 Protein

Hepatitis G virus (HGV or GB-C virus) is a newly described virus that is closely related to hepatitis C virus (HCV). Based on sequence analysis and by evaluation of translational initiation codon preferences utilized during in vitro translation, HGV appears to have a truncated or absent core protein at the amino terminus of the HGV polyprotein. Consequently, the biophysical properties of HGV may be very different from those of HCV. To characterize HGV particle types, we evaluated plasma from chronically infected individuals with and without concomitant HCV infection by using sucrose gradient centrifugation, isopycnic banding in cesium chloride, and saline density flotation centrifugation. Similar to HCV, HGV particles included an extremely-low-density virion particle (1.07 to 1.09 g/ml) and a nucleocapsid of ~1.18 g/ml. One major difference between the particle types was that HGV was consistently more stable in cesium chloride than HCV. Plasma samples from chronically HGV-infected individuals and controls were assessed by a synthetic peptide-based immunoassay to determine if they contained HGV antibody specific for a conserved region in the coding region upstream of the E1 protein. Chronically HGV-infected individuals contained antibody to the HGV core protein peptide, whereas no binding to a hepatitis A virus peptide control was observed. Competitive inhibition of binding to the HGV peptide confirmed the specificity of the assay. These data indicate that HGV has a nucleocapsid and that at least part of the putative core region of HGV is expressed in vivo.     

Molecular dissection of variation in carbohydrate metabolism related to water-soluble carbohydrate accumulation in stems of wheat

Water-soluble carbohydrates (WSCs; composed of mainly fructans, sucrose [Suc], glucose [Glc], and fructose) deposited in wheat (Triticum aestivum) stems are important carbon sources for grain filling. Variation in stem WSC concentrations among wheat genotypes is one of the genetic factors influencing grain weight and yield under water-limited environments. Here, we describe the molecular dissection of carbohydrate metabolism in stems, at the WSC accumulation phase, of recombinant inbred Seri/Babax lines of wheat differing in stem WSC concentrations. Affymetrix GeneChip analysis of carbohydrate metabolic enzymes revealed that the mRNA levels of two fructan synthetic enzyme families (Suc:Suc 1-fructosyltransferase and Suc:fructan 6-fructosyltransferase) in the stem were positively correlated with stem WSC and fructan concentrations, whereas the mRNA levels of enzyme families involved in Suc hydrolysis (Suc synthase and soluble acid invertase) were inversely correlated with WSC concentrations. Differential regulation of the mRNA levels of these Suc hydrolytic enzymes in Seri/Babax lines resulted in genotypic differences in these enzyme activities. Down-regulation of Suc synthase and soluble acid invertase in high WSC lines was accompanied by significant decreases in the mRNA levels of enzyme families related to sugar catabolic pathways (fructokinase and mitochondrion pyruvate dehydrogenase complex) and enzyme families involved in diverting UDP-Glc to cell wall synthesis (UDP-Glc 6-dehydrogenase, UDP-glucuronate decarboxylase, and cellulose synthase), resulting in a reduction in cell wall polysaccharide contents (mainly hemicellulose) in the stem of high WSC lines. These data suggest that differential carbon partitioning in the wheat stem is one mechanism that contributes to genotypic variation in WSC accumulation.     

Factors influencing the sporulation and cyst formation of Aphanomyces invadans, etiological agent of ulcerative mycosis in Atlantic menhaden, Brevoortia tyrannus

Oomycete infections caused by Aphanomyces invadans occur in freshwater and estuarine fishes around the world. Along the east coast of the USA, skin ulcers caused by A. invadans are prevalent in Atlantic menhaden, Brevoortia tyrannus. From laboratory observations low salinities appear crucial to transmission of the pathogen. To better understand aspects of transmission, we characterized sporulation and cyst formation of secondary zoospores of two isolates of A. invadans at different salinities and temperatures. Sporulation occurred only at low salinities. At room temperature (ca. 20-22 C), using pond water augmented with artificial sea salts, the endemic strain WIC and the Thailand strain PA7 of A. invadans produced free-swimming secondary zoospores at salinities of 0, 1 and 2 psu (practical salinity unit = per thousand), but not at 4 psu or higher. Secondary zoospores of another species, ATCC-62427 (Aphanomyces sp.), were observed at 1, 2, 4 and 8 psu but not at 0 and 12 psu. Secondary zoospores of all three isolates, especially WIC, were abundant and motile 1-2 d postsporulation. Sporulation was temperature dependent and occurred over a relatively narrow range. No sporulation occurred at 4, 30 or 35 C for either WIC or PA7. For both strains zoospore production within 1-3 d after the initiation of sporulation was more prolific at 25 C than at 20 and 15 C. At 15 C production of zoospores was sustained over 11 d for WIC and 5 d for PA7. At room temperature single WIC secondary zoospores remained motile 12-18 h. Salinities exceeding 4 psu or vigorous shaking caused immediate cyst formation of WIC secondary zoospores. Exposure to menhaden tissue, but not tissues of other fishes to secondary zoospores (WIC), caused rapid (2 h) cyst formation. Cysts were capable of excysting when transferred to 1 psu water within 2-3 h of cyst formation. Cysts that had remained encysted in 6.5 psu for 24 h did not excyst when transferred to 1 psu water. Salinity and temperature requirements for sporulation indicate that juvenile menhaden must acquire infections during rain or in low salinity oligohaline waters.     

Production of extracellular phytase fromAspergillus ficuum on starch media

Summary Cultures grown on Hylon corn starch media produced the highest levels of phytase. Phospholipid extraction of Hylon starch did not change its effectiveness as a substrate. Cultures grown on phosphorylated dextrins from Hylon corn starch produced equivalent amounts of phytase.