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Biomedical subjects

D L Rowley

Publications and source records attributed to D L Rowley.

At least 19 recordsLinked to original sources
PubMed2005

Barcoding generalist predators by polymerase chain reaction: carabids and spiders.

Identification of arthropod predators is challenging when closely related species are found at a given locality. Identification of the immature stages is especially problematic, because distinguishing morphological features are difficult to use or have not been described. We used polymerase chain reaction (PCR) to distinguish closely related carabids and spiders, and to match eggs and larvae (or nymphs) with identified adult parents. Within the Carabidae, we amplified species-specific mitochondrial cytochrome oxidase I (COI) fragments for three species each in the genera Poecilus and Harpalus, and two each in Chlaenius and Bembidion. Within the Araneae, we amplified species-specific COI fragments for two Hibana species (Anyphaenidae), Pardosa milvina and Rabidosa rabida (Lycosidae), Frontinella communis and Grammonota texana (Linyphiidae), and Cheiracanthium inclusum (Miturgidae). We are able to correctly identify all immature stages tested--eggs, larvae (or nymphs) and pupae--by comparison of the amplified fragments with those of the adults. Using COI markers as species identifiers is a tenet of the Barcode of Life initiative, an international consortium to provide a molecular identifier for every animal species.

Animals↗
PubMed2001

A murine dopamine neuron-specific cDNA library and microarray: increased COX1 expression during methamphetamine neurotoxicity.

Due to brain tissue heterogeneity, the molecular genetic profile of any neurotransmitter-specific neuronal subtype is unknown. The purpose of this study was to purify a population of dopamine neurons, construct a cDNA library, and generate an initial gene expression profile and a microarray representative of dopamine neuron transcripts. Ventral mesencephalic dopamine neurons were purified by fluorescent-activated cell sorting from embryonic day 13.5 transgenic mice harboring a 4.5-kb rat tyrosine hydroxylase promoter-lacZ fusion. Nine-hundred sixty dopamine neuron cDNA clones were sequenced and arrayed for use in studies of gene expression changes during methamphetamine neurotoxicity. A neurotoxic dose of methamphetamine produced a greater than twofold up-regulation of the mitochondrial cytochrome c oxidase polypeptide I transcript from adult mouse substantia nigra at 12 h posttreatment. This is the first work to describe a gene expression profile for a neuronal subtype and to identify gene expression changes during methamphetamine neurotoxicity.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2001

Murine inter-strain polymorphisms alter gene targeting frequencies at the mu opioid receptor locus in embryonic stem cells.

Chromosomal regions near the mu opioid receptor gene are implicated in morphine preference by quantitative trait loci studies. Differences in expression of the mu opioid receptor are expected to contribute to differences in inter-individual (humans) or strain-specific (mice) responses to painful stimuli, opiate drugs, and addictive behaviors. The search for relevant genetic elements is hindered by a lack of inter-strain (or inter-individual) genomic sequence information. This work describes 9.3 kb of DNA sequence surrounding exons 2 and 3 of the murine mu opioid receptor gene from both 129/Sv and C57BL/6 strains. While the exons are perfectly conserved, intronic sequences demonstrate approximately a 2.5% divergence between the strains. Polymorphism within these intronic regions may effect either primary transcript stability or C-terminal splicing. Homologous recombination frequencies of targeting vectors harboring mu opioid receptor gene sequences have also been compared in embryonic stem cells derived from these strains. Non-isogenic targeting reduces homologous recombination in both 129/Sv and C57BL/6 embryonic stem cells by greater than 15-fold. These findings are the first to examine C57BL/6 embryonic stem cells for non-isogenic targeting frequencies and to define polymorphisms that exist between these mouse strains which might contribute to opioid behaviors.

Alleles↗
PubMed2001

Closing the gap, opening the process: why study social contributors to preterm delivery among black women.

In the United States, the excess rates of infant mortality, VLBW, and preterm delivery among African American families relative to white families are known as "the gap." A group of researchers in the Division of Reproductive Health at the Centers for Disease Control and Prevention proposed that the study of causes of the gap in preterm delivery and the potential interventions to eliminate this disparity required a multidisciplinary approach to elucidate the biologic pathways, stressors, and social environment associated with preterm birth. They encouraged studies that examined the social and political impact of being an African American woman in the United States, racism, and the combined effects of gender, racism, and relative social position, as potential unmeasured etiologic factors that contribute to the gap. The studies conducted represent the expertise of anthropologists, sociologists, medical researchers, and epidemiologists who study both individual and social causes and then also provide a theoretical interpretation by those who lived the experience, (e.g., the study participants) rather than just the researchers' interpretation of the causes of and prevention strategies for the gap.

Black or African American↗
PubMed1997

The upstream domain of soybean oleosin genes contains regulatory elements similar to those of legume storage proteins.

Seed reserve storage products consisting of proteins, oil and starch are accumulated in a developmentally coordinated pattern. The control of the vacuolar storage protein expression has been shown to be transcriptionally regulated and involves a series of positive and negative regulatory as well as enhancing gene elements. We have analyzed the upstream sequence of the genes encoding the soybean oleosins, the protein that encases the oil body. We have found that soybean oleosin genes possess regulatory elements in upstream domain that are similar to those found in vacuolar storage protein genes.

Amino Acid Sequence↗
PubMed1996

Phenotypic expression of Pseudomonas syringae avr genes in E. coli is linked to the activities of the hrp-encoded secretion system.

The specific recognition of elicitors produced by plant pathogenic bacteria carrying avirulence (avr) genes is postulated to initiate cellular defense responses in plants expressing corresponding resistance genes. The biochemical functions of most avr genes, however, are not known. A heterologous system was developed to phenotypically express Pseudomonas syringae avr genes in Escherichia coli cells that required the P. syringae hrp cluster. E. coli MC4100 transformants carrying the plasmic-borne P. syringae pv. syringae Pss61 hrp cluster and p. syringae pv. glycinea avrB expressed from a triple lacUV5 promoter gained the ability to elicit the hypersensitive response in soybean cultivars expressing Rpg1 and in an Arabidopsis thaliana accession expressing RPM1. Inactivation of energy transducing or outer membrane components of the hrp-encoded secretion system blocked phenotypic expression expression of avrB in E. coli, but deletions abolishing harpinPSS production had little effect on the production of the AvrB phenotype by the E. coli transformants. Phenotypic expression of avrA, AvrPto, avrRpm1, avrRpt2, and avrPph3 in E. coli was also shown to require the hrp cluster. The results indicate that generation of the Avr phenotype in P. syringae strains is specifically dependent on the secretion activities of the hrp cluster.

Base Sequence↗
PubMed1995

Binding-protein expression is subject to temporal, developmental and stress-induced regulation in terminally differentiated soybean organs.

Binding protein (BiP) is a widely distributed and highly conserved endoplasmic-reticulum luminal protein that has been implicated in cotranslational folding of nascent polypeptides, and in the recognition and disposal of misfolded polypeptides. Analysis of cDNA sequences and genomic blots indicates that soybeans (Glycine max L. Merr.) possess a small gene family encoding BiP. The deduced sequence of BiP is very similar to that of other plant BiPs. We have examined the expression of BiP in several different terminally differentiated soybean organs including leaves, pods and seed cotyledons. Expression of BiP mRNA increases during leaf expansion while levels of BiP protein decrease. Leaf BiP mRNA is subject to temporal control, exhibiting a large difference in expression in a few hours between dusk and night. The expression of BiP mRNA varies in direct correlation with accumulation of seed storage proteins. The hybridization suggests that maturing-seed BiP is likely to be a different isoform from vegetative BiPs. Levels of BiP protein in maturing seeds vary with BiP mRNA. High levels of BiP mRNA are detected after 3 d of seedling growth. Little change in either BiP mRNA or protein levels was detected in maturing soybean pods, although BiP-protein levels decrease in fully mature pods. Persistent wounding of leaves by whiteflies induces massive overexpression of BiP mRNA while only slightly increasing BiP-protein levels. In contrast single-event puncture wounding only slightly induces additional BiP expression above the temporal variations. These observations indicate that BiP is not constitutively expressed in terminally differentiated plant organs. Expression of BiP is highest during the developmental stages of leaves, pods and seeds when their constituent cells are producing seed or vegetative storage proteins, and appears to be subject to complex regulation, including developmental, temporal and wounding.

Adaptation, Psychological↗
PubMed1994

Research issues in the study of very low birthweight and preterm delivery among African-American women.

Very low birthweight and preterm delivery explain two thirds of the excess deaths experienced by African-American infants. Although comprehensive, good quality services for all African-American women will help to reduce the twofold higher rate of infant mortality experienced by African-American infants compared with white infants, the infant mortality gap will not be closed until prevention research is conducted that incorporates the social, cultural, and political context of life for African-American women; the environmental stressors and the physiologic responses associated with stress; and the protective mechanisms available in the community for responding to stress. Discrimination may be an important stressor that influences a woman's susceptibility to a poor pregnancy outcome. Strategies already exist in the community to cope with discrimination and other environmental stressors. To capture the effects of discrimination and other environmental factors and the protective factors important for prevention, the research approach must involve African-American women and their communities as collaborators in the research. Such collaboration will help to avoid problems with scientific racism.

Black or African American↗
PubMed1993

The epidemiology of placenta previa in the United States, 1979 through 1987.

OBJECTIVE: Placenta previa can cause serious, occasionally fatal complications for fetuses and mothers; however, data on its national incidence and sociodemographic risk factors have not been available. STUDY DESIGN: We analyzed data from the National Hospital Discharge Survey for the years 1979 through 1987 and from the Retrospective Maternal Mortality Study (1979 through 1986). RESULTS: We found that placenta previa complicated 4.8 per 1000 deliveries annually and was fatal in 0.03% of cases. Incidence rates remained stable among white women but increased among black and other minority women (p < 0.1). In addition, the risk of placenta previa was higher for black and other minority women than for white women (rate ratio 1.3, 95% confidence interval 1.0 to 1.7), and it was higher for women > or = 35 years old than for women <20 years old (rate ratio 4.7, 95% confidence interval 3.3 to 7.0). Women with placenta previa were at an increased risk of abruptio placentae (rate ratio 13.8), cesarean delivery (rate ratio 3.9), fetal malpresentation (rate ratio 2.8), and postpartum hemorrhage (rate ratio 1.7). CONCLUSION: Our findings support the need for improved prenatal and intrapartum care to reduce the serious complications and deaths associated with placenta previa.

Adult↗
PubMed1993

Is race a risk factor or a risk marker for preterm delivery?

Reasons for the persistent difference in rates of preterm delivery among black and white women are not clear. Known risk factors explain very little of the variance. Recent studies have shown that social class does not fully account for poor pregnancy outcomes among black women. Cultural and environmental factors that vary between the races, but not between the different socioeconomic levels within a race, may account for some of the unexplained ethnic differences in preterm delivery. Any potentially negative exposure that is distributed differentially between racial groups warrants particular attention. The major hypothesis of this research is that US black women are chronically exposed to specific stressors that adversely affect the outcomes of their pregnancies. A psychosocial stress model has been proposed to explain the complex interactions of social, environmental, and medical factors that are unique among women of color. To generate data for the stress model, a research strategy has been designed to identify psychosocial and behavioral risk factors that have a physiologic impact on pregnancy outcome. We propose that race is a marker for this stress but is not in itself a risk factor for preterm delivery.

Black or African American↗
PubMed1993

Interactive effect of race and marital status in low birthweight.

Although unmarried mothers are at risk of delivering low-birthweight (LBW) infants, the meaning and significance of this variable need to be explored in depth. With data on 216,285 infants born to white and black mothers aged 10 to 49 years in Atlanta, Georgia, between 1980 and 1987, we examined the association of LBW and marital status and the effect of race on the association. Education and age were controlled in the analysis in an attempt to isolate the effect of race on the marital status and birthweight association. The crude LBW rate among infants born to unmarried mothers was about twice the rate among infants born to married mothers (132.8 vs 63.9 per 1000 live births). Adjustment singly for maternal race, age, and education gave risk ratios (unmarried vs married) of 1.50, 2.03, and 1.78, respectively. Simultaneous control for all factors led to a hierarchy of education-adjusted risk: unmarried black adult mothers had the highest risk of delivering an LBW infant (2.49), followed by married black adults (1.93), unmarried black teenagers (1.90), married black teenagers (1.67), unmarried white adults (1.65), unmarried white teenagers (1.35), married white teenagers (1.08), and married white adults (1.0; reference group, with an LBW rate of 51.2/1000 live births). Thus, these data demonstrate both a consistently higher risk for black women and an interactive effect of age on the association of marital status and LBW: unmarried status appears to increase the risk of LBW much more among adult women than among younger women. This finding has implications for research and prevention of LBW.

Adolescent↗
PubMed1992

Preterm delivery and low birth weight among first-born infants of black and white college graduates.

Reproductive outcomes were investigated in black and white female college graduates, presumed to be of similar socioeconomic status and similar risk profile with respect to environmental factors. Data were gathered by mail survey from graduates (1973-1985) of four Atlanta, Georgia, colleges between February and June 1988. Of 6,867 alumnae to whom questionnaires were mailed, 3,084 responded. A follow-up study of black nonrespondents yielded responses from 14% (335) of those who did not respond to the mail survey. For all graduates with a first live born at the time of survey (n = 1,089), the rates of preterm delivery, low birth weight, and infant mortality were 80.8, 82.6, and 14.6 per thousand births (primigravida), respectively. Compared with white graduates, black graduates had 1.67 times the risk of preterm delivery and 2.48 times the risk of low birth weight. Measures of social and economic status differed significantly by race. However, adjustment for these variables did not reduce the estimated risk for black graduates compared with whites. Analysis of the nonresponder survey suggested that respondent data alone overestimates the incidence of adverse outcomes in blacks; using nonresponder data, relative risks of 1.28 (preterm delivery) and 1.75 (low birth weight) were calculated as lower limits of the increased risk for blacks.

Adult↗
PubMed1992

Molecular characterization of mutations affecting expression level and growth rate-dependent regulation of the Escherichia coli zwf gene.

We characterized three cis dominant mutations which elevate glucose 6-phosphate dehydrogenase level. Growth rate-dependent regulation and oxidative stress control of enzyme level were altered by the mutations. DNA sequencing and transcript mapping showed that the "up" mutations created new promoters whose hyperactive expression overrides the normal regulation of the native promoter.

Base Sequence↗
PubMed1991

Genetic and physical analyses of the growth rate-dependent regulation of Escherichia coli zwf expression.

Growth rate-dependent regulation of the level of Escherichia coli glucose 6-phosphate dehydrogenase, encoded by zwf, and 6-phosphogluconate dehydrogenase, encoded by gnd, is similar during steady-state growth and after nutritional upshifts. To determine whether the mechanism regulating zwf expression is like that of gnd, which involves a site of posttranscriptional control located within the structural gene, we prepared and analyzed a set of zwf-lacZ protein fusions in which the fusion joints are distributed across the glucose 6-phosphate dehydrogenase coding sequence. Expression of beta-galactosidase from the protein fusions was as growth rate dependent as that of glucose 6-phosphate dehydrogenase itself, indicating that regulation does not involve an internal regulatory region. The level of beta-galactosidase in zwf-lac operon fusion strains and the level of zwf mRNA from a wild-type strain increased with increasing growth rate, which suggests that growth rate control is exerted on the mRNA level. The half-life of the zwf mRNA mass was 3.0 min during growth on glucose and 3.4 min during growth on acetate. Thus, zwf transcription appears to be the target for growth rate control of the glucose 6-phosphate dehydrogenase level.

Base Sequence↗
PubMed1991

Molecular characterization of the Escherichia coli K-12 zwf gene encoding glucose 6-phosphate dehydrogenase.

In Escherichia coli K-12, expression of zwf, the gene for glucose 6-phosphate dehydrogenase, is coordinated with the cellular growth rate and induced by superoxide-generating agents. To initiate the study of the molecular mechanisms regulating its expression, the gene was cloned and its DNA sequence was determined. The 5' ends of zwf mRNA isolated from cells growing in glucose and acetate minimal media were mapped. The map was complex in that transcripts mapped to -45, -52, and -62, with respect to the beginning of the coding sequence. Three analytical methods were used to search the DNA sequence for putative promoters. Only one sequence for a promoter recognized by the sigma 70 form of RNA polymerase was found by all three search routines that could be aligned with a mapped transcript, indicating that the other transcripts arise by processing of the mRNA. A computer-assisted search did not reveal a thermodynamically stable long-range mRNA secondary structure that is capable of sequestering the translation initiation region, which suggests that growth-rate-dependent regulation of glucose 6-phosphate dehydrogenase level may not be carried out by a mechanism similar to the one for the gene (gnd) for 6-phosphogluconate dehydrogenase. The DNA segment between the -10 hexamer and the start point of transcription resembles the discriminator sequence of stable RNA genes, which has been implicated in stringent control and growth-rate-dependent regulation.

Amino Acid Sequence↗