Effects of urbanization on the population structure of freshwater turtles across the United States.

Landscape-scale alterations that accompany urbanization may negatively affect the population structure of wildlife species such as freshwater turtles. Changes to nesting sites and higher mortality rates due to vehicular collisions and increased predator populations may particularly affect immature turtles and mature female turtles. We hypothesized that the proportions of adult female and immature turtles in a population will negatively correlate with landscape urbanization.

Foliar injury, leaf gas exchange and biomass responses of black cherry (Prunus serotina Ehrh.) half-sibling families to ozone exposure.

Open pollinated families of black cherry seedlings were studied to determine genotypic differences in foliar ozone injury and leaf gas exchange in 1994 and growth response following three growing seasons. An O(3)-sensitive half-sibling family (R-12) and an O(3)-tolerant half-sibling family (MO-7) planted in natural soil were studied along with generic nursery stock (NS) seedlings. Ozone exposure treatments were provided through open top chambers and consisted of 50, 75, and 97% of ambient ozone, and open plots from May 9 to August 26, 1994.

Leaf morphology and ozone sensitivity of two open pollinated genotypes of black cherry (Prunus serotina) seedlings.

Two black cherry families differing in sensitivity to ozone (O(3)) were used to test the hypothesis that leaf morphology is related to foliar sensitivity to O(3). Two uninjured sections of leaf tissue were sampled from a single leaf collected from each of 12 open-grown O(3)-tolerant and 12 O(3)-sensitive seedlings. Standard histological techniques and light microscopy were used to examine 11 morphological characteristics.

Responses of pregnant women to potential preterm labor symptoms.

Objective: To examine the knowledge that healthy pregnant women have of appropriate actions to take in response to hypothetical symptoms of preterm labor.

Design: This was a descriptive, correlational study using a convenience sample.

Setting: Subjects were recruited from the private practices of obstetricians and nurse-midwives.

Predicting Ozone Uptake from Meteorological and Environmental Variables.

Predictions of foliar ozone uptake rates of seedling and canopy black cherry trees (Prunus serotina Ehrh.) were made using concurrent measurements of ambient ozone concentration and other environmental and meteorological data during two growing seasons in north-central Pennsylvania.

Light environment alters ozone uptake per net photosynthetic rate in black cherry trees.

Foliar ozone uptake rates of different-sized black cherry (Prunus serotina Ehrh.) trees were compared within a deciduous forest and adjacent openings in north-central Pennsylvania during one growing season. Study trees included open-grown seedlings and saplings, forest understory seedlings and saplings, and sunlit and shaded portions of mature canopy tree crowns.

Vertical gradients of ozone and carbon dioxide within a deciduous forest in Central Pennsylvania.

Ambient concentrations of ozone (O(3)) and carbon dioxide (CO(2)) were measured at locations from the forest floor to the top of the canopy in a deciduous forest at the Moshannon State Forest in northcentral Pennsylvania. O(3) concentrations were measured from May-September for three years (1993-1995) while CO(2) concentrations were measured only during July and August of 1994. O(3) concentrations increased steadily during the day at all locations, peaking during the middle to late afternoon hours.

Size-mediated foliar response to ozone in black cherry trees.

Local ozone concentration and visible foliar injury were measured over the 1994 growing season on open-grown black cherry (Prunus serotina Ehrh.) trees of varying size (age) within forest stands and adjacent openings at a site in north-central Pennsylvania. Relationships were determined between visible ozone injury and ozone exposure, as well as calculated between injury and ozone uptake expressed as the product of stomatal conductance and ozone concentration.

Physiology, morphology, and ozone uptake of leaves of black cherry seedlings, saplings, and canopy trees.

Patterns of ozone uptake were related to physiological, morphological, and phenological characteristics of different-sized black cherry trees (Prunus serotina Ehrh.) at a site in central Pennsylvania. Calculated ozone uptake differed among open-grown seedlings, forest gap saplings, and canopy trees and between leaves in the upper and lower crown of saplings and canopy trees.

Adaptation of the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay for the determination of virus-neutralizing antibodies using the virus-neutralization assay.

The tetrazolium salt MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] has been widely used for bioassays. Herein is described the use of the MTT dye with a virus-neutralization (VN) assay to titer infectious bursal disease virus (IBDV)-neutralizing antibodies. A standard VN assay using chicken embryo fibroblasts (CEFs) and IBDV was used for the assessment of IBDV-neutralizing antibodies.

Virus isolation accuracy: an evaluation of eight laboratories involved in poultry diagnostics.

A study was undertaken to evaluate the accuracy of diagnostic laboratories at isolation of common avian viral pathogens. Fourteen "unknown" samples were submitted to eight laboratories in seven states. All positive and negative samples were guaranteed pure by SPAFAS.

High-performance liquid chromatographic method for the determination of spectinomycin in turkey plasma.

A selective high-performance liquid chromatographic (HPLC) method with ultraviolet-visible (UV-VIS) detection was developed to measure therapeutic concentrations of spectinomycin in turkey plasma. Treatment of plasma samples with 3% trifluoroacetic acid in acetonitrile facilitated spectinomycin extraction and protein precipitation. After centrifugation, the stable derivatization reagent, 2,4-dinitrophenyl-hydrazine, was added to an aliquot of the supernatant, and the mixture was incubated for 30 min at 70 degrees C.

Purification of avian T cell growth factor and immune interferon using gel filtration high resolution chromatography.

A protocol was outlined to separate and purify chicken T cell growth factor or IL-2 and gamma interferon from conditioned medium of Con A activated spleen cells. IL-2 was associated primarily with a protein of 30 kDa in SDS-PAGE and in high resolution gel filtration chromatography. Chicken IL-2 was of low hydrophobicity.

Mechanism of T cell immunosuppression by infectious bursal disease virus of chickens.

Spleen cells of chickens infected with IBDV responded poorly to in vitro stimulation with Con A. The mitogenic hyporesponsiveness was due to the presence of suppressor cells that could be removed by pretreatment of IS cells with carbonyl iron or cytodex-3 microcarrier beads. Addition of suppressor cells to normal spleen cells prevented the normal cells from responding to mitogen.

Genetic interaction between non-MHC T- and B-cell alloantigens in response to Rous sarcomas in chickens.

Chickens of Regional Poultry Research Laboratory (RPRL) inbred line 6(3) regress sarcomas induced by Bryan high-titer Rous sarcoma virus to a greater extent than chickens of line RPRL 100, although these lines are identical for the major histocompatibility B complex. They differ, however, at three independent autosomal loci: Ly-4 and Th-1 determine the surface alloantigens of partly overlapping subsets of T lymphocytes, and Bu-1 determines a surface alloantigen of B lymphocytes. The association of genotypes at these loci with quantitative variation in their ability to regress Rous sarcomas was tested in segregating F4 generation progeny derived from crosses of lines 100 and 6(3).

Strong suppression by monocytes of T cell mitogenesis in chicken peripheral blood leukocytes.

Peripheral blood leukocytes (PBL) isolated from chicken blood by flotation on Ficoll-Hypaque (FH) have much lower proliferative responses to Con A and PHA than PBL isolated by slow-speed (SS) centrifuging at 60 X G. FH preparations contain all categories of blood cells except erythrocytes, whereas SS are almost devoid of nonlymphoid cells. FH responses approach SS levels after filtration through Sephadex G-10, which removes almost all monocytes detectable by neutral red and nonspecific esterase methods, while only partially depleting granulocytes and thrombocytes.

Influence of genotypes at a non-MHC B lymphocyte alloantigen locus (Bu-1) on expression of Ia (B-L) antigen on chicken bursal lymphocytes.

Two inbred lines of chickens known to be identical at the MHC differ in their expression of Ia antigen on cells of the bursa. Line 6 bursas had 23% of intensely staining Ia+ cells while line 7 bursas had a much higher level, 85%. Studies of F4 progeny of line 6(3) X 100 crosses showed that genetic control of the high bursal proportion of Ia+ cells was determined by the Bu-1 alloantigen system.

Tests of association of lymphocyte alloantigen genotypes with resistance to viral oncogenesis in chickens. 2. Rous sarcoma and lymphoid leukosis in progeny derived from 6(3) X 15(1) and 100 X 6(3) crosses.

Chickens from inbred line RPRL 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally induced Rous sarcomas. Line 6(3) chickens are homozygous for three independent loci determining surface alloantigens of lymphocytes, Th-1 and Ly-4 on thymus-derived (T) cells and Bu-1 on bursa-derived (B) cells. In contrast, RPRL Lines 100 and 15(1) are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than 6(3).

Ontogeny of con A and PHA responses of chicken blood cells in MHC-compatible lines 6(3) and 7(2).

The development of T cell responsiveness to Con A and PHA was examined in two MHC-compatible inbred chicken lines, RPRL 6(3) and 7(2), at ages 2 to 118 days posthatching. These lines are respectively resistant or susceptible to Marek's disease, a naturally occurring, virally induced T cell lymphoma. Between-line comparisons were made of optimal in vitro responses of diluted serum-free blood cells to each mitogen in two groups of chicks tested over ages 2 to 63 and 41 to 118 days.

Influence of non-MHC T lymphocyte alloantigens on regression of Rous sarcomas in the chicken.

Chickens of Regional Poultry Research Laboratory (RPRL) inbred line 6(3) regress sarcomas induced by Bryan high-titer Rous sarcoma virus to a greater extent than chickens of line 7(2), although these lines are identical for the major histocompatibility complex (MHC, B complex). They differ, however, at two independent autosomal loci, Ly-4 and Th-1, which determine surface alloantigens of partly overlapping subsets of T lymphocytes. Association of genotypes at these loci with quantitative variation in ability to regress Rous sarcomas was tested in segregating progeny derived from crosses of lines 6(3) and 7(2).

Tests of association of lymphocyte alloantigen genotypes with resistance to viral oncogenesis in chickens. 1. Marek's disease in F7 progeny derived from 6(3) X 15(1) crosses.

Marek's disease (MD)-susceptible progeny of the B5B5 genotype from the F7 generation derived from crosses of Regional Poultry Research Laboratory inbred lines 6(3) and 15(1) were tested for variation in MD resistance associated with the T lymphocyte antigen loci Ly-4 and Th-1. The four double homozygous genotypic classes of Ly-4 and Th-1 were tested in a 2 X 2 design. The Ly-4bb/Th-1aa chickens were significantly more resistant to MD oncogenesis than the other three genotypes.