Antigen-binding cells in the peripheral blood of sockeye salmon, Oncorhynchus nerka Walbaum, induced by immersion or intraperitoneal injectijon of Vibro anguillarum bacterin

We used an immunocytoadherence assay to monitor the response of antigen-binding cells (ABC) in the peripheral blood of sockeye salmon, Oncorhynchus nerka , after immersion in, or intraperitoneal injection of, Vibrio anguillarum LS 1–74 bacterin. Both methods initiated an elevated ABC response in less than one day; this response persisted one week longer in the injected than in the immersed fish.     

Selective Constraint on Copy Number Variation in Human Piwi-Interacting RNA Loci

Piwi-interacting RNAs (piRNAs) are a recently discovered class of small non-coding RNA found in animals. PiRNAs are primarily expressed in the germline where their best understood function is to repress transposable elements. Unlike previous studies that investigated the evolution of piRNA-generating loci at the level of nucleotide substitutions, here we studied the evolution of piRNA-generating loci at the level of copy number variation (i.e. duplications and deletions) using genome-wide copy number variation data from three human populations. Our analysis shows that at the level of copy number variation there is strong selective constraint and a very high mutation rate in human piRNA-generating loci. Our results differ from a model of positive selection on copy number variation in piRNA-generating loci previously proposed in rodents. We discuss possible reasons for this difference based on the transposable element insertion histories in the rodent and primate lineages.     

Functional role of anthocyanins in the leaves of Quintinia serrata A. Cunn

The protective functions that have been ascribed to anthocyanins in leaves can be performed as effectively by a number of other compounds. The possibility that anthocyanins accumulate most abundantly in leaves deficient in other phytoprotective pigments has been tested. Pigment concentrations and their histological distribution were surveyed for a sample of 1000 leaves from a forest population of Quintinia serrata, which displays natural polymorphism in leaf colour. Eight leaf phenotypes were recognized according to their patterns of red coloration. Anthocyanins were observed in almost all combinations of every leaf tissue, but were most commonly located in the vacuoles of photosynthetic cells. Red leaves contained two anthocyanins (Cy-3-glc and Cy-3-gal), epicuticular flavones, epidermal flavonols, hydroxycinnamic acids, chlorophylls, and carotenoids. Green leaves lacked anthocyanins, but had otherwise similar pigment profiles. Foliar anthocyanin levels varied significantly between branches and among trees, but were not correlated to concentrations of other pigments. Anthocyanins were most abundant in older leaves on trees under canopies with south-facing gaps. These data indicate that anthocyanins are associated with photosynthesis, but do not serve an auxiliary phytoprotective role. They may serve to protect shade-adapted chloroplasts from brief exposure to high intensity sunflecks.     

Natural and experimental West Nile virus infection in five raptor species

We studied the effects of natural and/or experimental infections of West Nile virus (WNV) in five raptor species from July 2002 to March 2004, including American kestrels (Falco sparverius), golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), barn owls (Tyto alba), and great horned owls (Bubo virginianus). Birds were infected per mosquito bite, per os, or percutaneously by needle. Many experimentally infected birds developed mosquito-infectious levels of viremia (>10(5) WNV plaque forming units per ml serum) within 5 days postinoculation (DPI), and/ or shed virus per os or per cloaca. Infection of organs 15-27 days postinoculation was infrequently detected by virus isolation from spleen, kidney, skin, heart, brain, and eye in convalescent birds. Histopathologic findings varied among species and by method of infection. The most common histopathologic lesions were subacute myocarditis and encephalitis. Several birds had a more acute, severe disease condition represented by arteritis and associated with tissue degeneration and necrosis. This study demonstrates that raptor species vary in their response to WNV infection and that several modes of exposure (e.g., oral) may result in infection. Wildlife managers should recognize that, although many WNV infections are sublethal to raptors, subacute lesions could potentially reduce viability of populations. We recommend that raptor handlers consider raptors as a potential source of WNV contamination due to oral and cloacal shedding.     

Genetic bases of estrogen-induced pituitary tumorigenesis: identification of genetic loci determining estrogen-induced pituitary growth in reciprocal crosses between the ACI and Copenhagen rat strains

Estrogens stimulate proliferation and enhance survival of the prolactin (PRL)-producing lactotroph of the anterior pituitary gland and induce development of PRL-producing pituitary tumors in certain inbred rat strains but not others. The goal of this study was to elucidate the genetic bases of estrogen-induced pituitary tumorigenesis in reciprocal intercrosses between the genetically related ACI and Copenhagen (COP) rat strains. Following 12 weeks of treatment with the synthetic estrogen diethylstilbestrol (DES), pituitary mass, an accurate surrogate marker of absolute lactotroph number, was increased 10.6-fold in ACI rats and 4.5-fold in COP rats. Composite interval mapping analyses of the phenotypically defined F(2) progeny from the reciprocal crosses identified six quantitative trait loci (QTL) that determine the pituitary growth response to DES. These loci reside on chromosome 6 [Estrogen-induced pituitary tumor (Ept)1], chromosome 3 (Ept2 and Ept6), chromosome 10 (Ept9), and chromosome 1 (Ept10 and Ept13). Together, these six Ept loci and one additional suggestive locus on chromosome 4 account for an estimated 40% of the phenotypic variance exhibited by the combined F(2) population, while 34% of the phenotypic variance was estimated to result from environmental factors. These data indicate that DES-induced pituitary mass behaves as a quantitative trait and provide information that will facilitate identification of genes that determine the tumorigenic response of the pituitary gland to estrogens.     

Well differentiated and small cell neuroendocrine carcinomas of the lung. Two related but distinct clinicopathologic entities

Twenty-two resected pulmonary well differentiated neuroendocrine carcinomas (WDNC) were re-evaluated histologically as were 28 resected intermediate-small cell neuroendocrine carcinomas (IC-SCNC). WDNC were distinguishable from IC-SCNC by their consistently recognizable organoid architecture, and by the absence or limited extent of necrosis. Furthermore, WDNC could be subclassified into 3 subsets based upon the degrees of pleomorphism, local and vascular invasion, and stromal fibrosis, the mitotic count, and the extent of tumor necrosis. Whereas all those parameters were important in discriminating between WDNC and IC-SCNC, the quality of the organoid architecture, and the extent and pattern of necrosis emerged as the most significant. WDNC with the more aggressive histologic features (subset III) had, as a group, a distinctly worse clinical course that those displaying blander features (subsets I and II). Nevertheless, even subset III of WDNC had, as a group, a longer survival than similarly treated Stages I and II IC-SCNC. We conclude that the histologic spectrum of WDNC is broader than generally recognized. Moreover, 3 subsets of WDNC are definable based on conventional histologic criteria provided sufficient, well preserved samples are examined. Even the most aggressive subset of WDNC can be thus histologically discriminated from IC-SCNC, and, given comparable stages, has a better prognosis than the latter.     

A re-examination of the reaction between ox liver glutamate dehydrogenase and 1-fluoro-2,4-dinitrobenzene.

Reaction of ox liver glutamate dehydrogenase with 1-fluoro-2,4-dinitrobenzene for 4 h at pH 8 caused 86% inactivation, almost complete desensitization to allosteric inhibition by GTP, but only partial desensitization to ADP activation. The enzyme remained hexameric after such treatment. NAD⁺, but not NADH or NADPH, partially protected activity. Protection was enhanced by GTP and decreased by ADP. GTP and NADH together protected effectively, although separately neither protected. GTP and NADPH gave partial protection of activity. Glutarate and succinate, inhibitors competitive with glutamate, gave substantial protection, slightly enhanced in the presence of NAD⁺. With glutarate, but not succinate, an initial activation was seen during chemical modification. The allosteric response to GTP was protected by GTP itself only when NAD⁺ or NAD(P)H was also present; other ligands failed to protect. Similarly ADP alone did not protect ADP sensitivity. NADH partially protected ADP sensitivity, although NADPH did not. ADP itself counteracted the protection given by NADH. GTP with NADH completely protected ADP sensitivity. This combination of ligands thus protects all the assayed properties. GTP with NADPH gave less complete protection of the ADP response. Observed protection patterns varied with the pH and coenzyme concentration of the assay mixture under constant conditions of chemical modification. Overall, the results are inconsistent with the view that dinitrophenylation directly blocks nucleotide binding sites, and suggest rather that it interferes with communication between sites.