Biomedical subjects

J J Stuart

Publications and source records attributed to J J Stuart.

At least 19 recordsLinked to original sources

PubMed2005

Expression of Cyp6g1 and Cyp12d1 in DDT resistant and susceptible strains of Drosophila melanogaster.

The Rst(2)DDT locus (loci) in Drosophila is associated with the over-expression of two cytochrome P450 genes, Cyp6g1 and Cyp12d1. Using northern and western blot analysis we observed the expression pattern of these two genes in two DDT susceptible (Canton-S and 91-C) and three DDT resistant strains (Wisconsin, 91-R and Hikone-R). In Canton-S and 91-R, the CYP6G1 protein was constitutively expressed throughout development. In the Wisconsin strain, CYP6G1 was not expressed in third instar larvae unless the larvae are exposed to DDT. CYP12D1 protein was only expressed in adults. Cyp12d1 mRNA is induced in DDT resistant strains post-exposure to DDT and the expression patterns of Cyp12d1 mRNA varied across DDT resistant strains. Our data support the hypothesis that there is evolutionary plasticity in the expression patterns of P450s associated with metabolic pesticide resistance.

Animals↗

PubMed2005

Molecular cloning and characterization of two digestive serine proteases from the Hessian fly, Mayetiola destructor.

Full-length cDNA and genomic sequences for two genes (designated mdesprot-I and mdesprot-II) encoding digestive serine proteases in Hessian fly, Mayetiola destructor, have been cloned and characterized. The deduced amino acid sequences revealed similarity with trypsin-like digestive serine proteases from other Dipterans. Both mdesprot-I and mdesprot-II encoded proteins with secretion signal peptides at the N-terminals, indicating the proteins are secreted proteases that should function as midgut digestive proteases. A cytological analysis with fluorescent in situ hybridization revealed the cytological localization of mdesprot-I and mdesprot-II on the long arm of Autosome 2. Results are discussed in the context of the efficacy of potential protease inhibitors to develop Hessian fly resistant wheat through genetic engineering approaches.

Amino Acid Sequence↗

PubMed2004

A group of related cDNAs encoding secreted proteins from Hessian fly [Mayetiola destructor (Say)] salivary glands.

A group of cDNAs has been isolated and characterized from Hessian fly [Mayetiola destructor (Say)] salivary glands. Members in this group appear to encode proteins with secretion signal peptides at the N-terminals. The mature putative proteins are small, basic proteins with calculated molecular weights that ranged from 8.5 to 10 kDa, and isoelectric points from 9.92 to 10.90. Sequence analysis indicated a strong selection for mutations that generate amino acid changes within the coding region. Northern blot analysis revealed that these genes are expressed only in the first instar larvae, a critical stage that determines if the interaction between a specific Hessian fly biotype and a specific wheat cultivar is compatible. Genomic analysis demonstrated that multiple copies of similar genes are clustered within a short region on chromosome 2A. This is the same arm in which two avirulence genes have been mapped.

Amino Acid Sequence↗

PubMed2002

Grasses and gall midges: plant defense and insect adaptation.

The interactions of two economically important gall midge species, the rice gall midge and the Hessian fly, with their host plants, rice and wheat, respectively, are characterized by plant defense via R genes and insect adaptation via avr genes. The interaction of a third gall midge species, the orange wheat blossom midge, with wheat defense R genes has not yet exhibited insect adaptation. Because of the simple genetics underlying important aspects of these gall midge-grass interactions, a unique opportunity exists for integrating plant and insect molecular genetics with coevolutionary ecology. We present an overview of some genetic, physiological, behavioral, and ecological studies that will contribute to this integration and point to areas in need of study.

Adaptation, Physiological↗

PubMed2000

The 3' UTR of human MnSOD mRNA hybridizes to a small cytoplasmic RNA and inhibits gene expression.

Human MnSOD localizes to the mitochondria and plays a key protective role by detoxifying oxygen free radicals. The MnSOD mRNA 3' UTR contains a 280-bp region (Alu-like element or Alu-E) that shows high homology to human Alu and 7SL sequences. MnSOD 3' UTR probes hybridize to a specific cytoplasmic RNA species of approximately 300 nucleotides. This antisense RNA is most likely 7SL RNA based on its size, ubiquitousness, high levels, and lack of inducibility. Hybridization of this small RNA to the MnSOD 3' UTR may modulate posttranscriptional MnSOD gene expression. This regulation could occur by several means including inhibition of translation and mRNA destabilization. Regulation at the level of translational initiation does not seem to occur as MnSOD mRNA containing the Alu-E is efficiently bound by ribosomes. To test the role of the MnSOD 3' UTR, and in particular the Alu-E in gene expression, luciferase reporter gene constructs were made containing various regions of the MnSOD 3' UTR including the Alu-E. These constructs were transfected into human A549 lung carcinoma cells and luciferase activity was measured. Reporter constructs containing the MnSOD 3' UTR and the Alu-E repress luciferase activity. Taken together, these results suggest that naturally occurring antisense RNA may bind MnSOD mRNA and repress its expression. These results also suggest that other mRNAs containing Alu elements may be similarly repressed.

3' Untranslated Regions↗

PubMed1999

Molecular genetic mapping of three X-linked avirulence genes, vH6, vH9 and vH13, in the Hessian fly.

Three X-linked avirulence genes, vH6, vH9, and vH13 in the Hessian fly, Mayetiola destructor, confer avirulence to Hessian fly resistance genes H6, H9, and H13 in wheat. We used a combination of two- and three-point crosses to determine the order of these genes with respect to each other, the white eye mutation and three X-linked molecular markers, G15-1, 020, and 021, developed from genomic lambda clones, lambda G15-1, lambda 020, and lambda 021. The gene order was determined to be vH9-vH6-G15-1-w-vH13-020-021. In situ hybridization of lambda G15-1, lambda 020, and lambda 021, on the polytene chromosomes of the Hessian fly salivary gland established their orientation on Hessian fly chromosome X1. Based on the size of the Hessian fly genome, and the genetic distances between markers, the relationship of physical to genetic distance was estimated at no more than 300 kb/cM along Hessian fly chromosome X1, suggesting that map-based cloning of these avirulence genes will be feasible.

Animals↗

PubMed1998

Genetic mapping of a major locus controlling pyrethroid resistance in Tribolium castaneum (Coleoptera: Tenebrionidae).

Tribolium castaneum (Herbst) strain QTC279 is highly resistant to deltamethrin and other synthetic pyrethroids. This strain was shown to carry at least 1 resistance gene, PyR-1, on linkage group 9, approximately 20 map units from the visible mutant marker, pearl. Three-point mapping involving pearl and another visible mutant marker, cola, indicated a gene order of pearl-cola-PyR-1. Evidence of a 2nd LG9-linked resistance factor (R) mapping in the gene order R-p-co was also observed. Other resistance factors were clearly present in QTC279, but were not genetically mapped. Piperonyl butoxide, an inhibitor of cytochrome P450-mediated oxidative metabolism, significantly increased the toxicity of deltamethrin to a strain derived from QTC279 that carries PyR-1, strain pR. Compared to susceptible beetles, QTC279 and pR had elevated and comparable levels of cytochrome P450 protein. The significance of pyrethroid resistance in T. castaneum is discussed.

Animals↗

PubMed1998

Genetic mapping of Hessian fly avirulence gene vH6 using bulked segregant analysis.

The Hessian fly, Mayetiola destructor (Say), an important insect pest of wheat, Triticum aestivum L., has a gene-for-gene relationship with wheat: single genes in the insect condition avirulence to specific resistance genes in wheat. We report the discovery of the first molecular genetic marker that is tightly linked to a Hessian fly avirulence gene. This dominant DNA polymorphism (OPG15-1) was identified using bulked segregant analysis and arbitrary primers in polymerase chain reactions. Bulked segregant analysis was modified to accommodate the anomalous chromosome cycle of the Hessian fly. It was used to identify DNA polymorphisms linked to the gene (vH6) that confers avirulence to the resistance gene H6 in wheat. OPG15-1 was cloned and sequenced, and a pair of site-specific primers were designed that converted it into a codominant single-stranded conformational polymorphism. Both OPG15-1 and vH6 were shown to be X-linked, and the genetic distance between the two loci was 2.5 +/- 2.5 cM. In situ hybridization to polytene chromosomes of larval salivary glands indicated that OPG15-1 resides near the centromere of Hessian fly chromosome X1.

Animals↗

PubMed1996

Useful DNA polymorphisms are identified by snapback, a midrepetitive element in Tribolium castaneum.

The red flour bettle, Tribolium castaneum, is both a pest of stored grain products and an important experimental organism. To improve its facility as a genetic model, we are developing DNA fingerprinting methods for this insect. A Tribolium DNA fragment, snapback-1 (SBI), identified among sequences that reassociate before a Cot of 0.03 mol.s/L, was found to produce a banding pattern in restriction endonuclease digested genomic DNA that is characteristic of a midrepetitive element. DNA fingerprints of individual beetles demonstrated that unvarying inherited DNA polymorphism is revealed, and that polymorphism is inherited in a dominant Mendelian fashion. Linkage between bands was minimal. The sequence of SBI was determined, and hybridization experiments indicated that SBI is a fragment of a larger midrepetitive element. Fingerprinting individuals with known inbreeding coefficients indicated that SBI loci have relatively high mutation rates. The possibility that SBI is a fragment of a transposable element is discussed.

Animals↗

PubMed1994

Predictive value of blood clotting tests in cardiac surgical patients.

This study prospectively evaluated numerous tests of clotting function in 897 consecutive adult cardiac surgical patients over 18 months. This included coronary operation, valve replacement, and reoperative patients. The tests included activated clotting time, activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, fibrin/fibrinogen degradation products, platelet count, and Duke's earlobe bleeding time. Other variables such as age, sex, and cardiopulmonary bypass duration were included in the multivariate analysis. Statistically significant correlations were found between 16-hour mediastinal drainage and activated partial thromboplastin time, fibrinogen, activated clotting time, fibrin/fibrinogen degradation products, platelet count, and prothrombin time. Scatter plots indicate that these relationships, although statistically significant, had little predictive value and were largely significant as a result of the large number of patients in each group, which permitted weak correlations to reach statistical significance. The best multivariate model constructed could explain only 12% of the observed variation in postoperative blood loss. Because the predictive values of the tests are so low, it does not appear sensible to screen patients routinely using these clotting tests shortly after cardiopulmonary bypass.

Adult↗

PubMed1993

Structure and function of the homeotic gene complex (HOM-C) in the beetle, Tribolium castaneum.

The powerful combination of genetic, developmental and molecular approaches possible with the fruit fly, Drosophila melanogaster, has led to a profound understanding of the genetic control of early developmental events. However, Drosophila is a highly specialized long germ insect, and the mechanisms controlling its early development may not be typical of insects or Arthropods in general. The beetle, Tribolium castaneum, offers a similar opportunity to integrate high resolution genetic analysis with the developmental/molecular approaches currently used in other organisms. Early results document significant differences between insect orders in the functions of genes responsible for establishing developmental commitments.

Animals↗

PubMed1993

The Tribolium homeotic gene Abdominal is homologous to abdominal-A of the Drosophila bithorax complex.

The Abdominal gene is a member of the single homeotic complex of the beetle, Tribolium castaneum. An integrated developmental genetic and molecular analysis shows that Abdominal is homologous to the abdominal-A gene of the bithorax complex of Drosophila. abdominal-A mutant embryos display strong homeotic transformations of the anterior abdomen (parasegments 7-9) to PS6, whereas developmental commitments in the posterior abdomen depend primarily on Abdominal-B. In beetle embryos lacking Abdominal function, parasegments throughout the abdomen are transformed to PS6. This observation demonstrates the general functional significance of parasegmental expression among insects and shows that the control of determinative decisions in the posterior abdomen by homeotic selector genes has undergone considerable evolutionary modification.

Amino Acid Sequence↗

PubMed1991

A deficiency of the homeotic complex of the beetle Tribolium.

In Drosophila, the establishment of regional commitments along most of the anterior/posterior axis of the developing embryo depends on two clusters of homeotic genes: the Antennapedia complex (ANT-C) and the bithorax complex (BX-C). The red flour beetle has a single complex (HOM-C) representing the homologues of the ANT-C and BX-C in juxtaposition. Beetles trans-heterozygous for two particular HOM-C mutations spontaneously generate a large deficiency, presumably by an exchange within the common region of two overlapping inversions. Genetic and molecular results indicate that this deficiency spans at least the interval between the Deformed and abdominal-A homologues. In deficiency homozygous embryos, all gnathal, thoracic and abdominal segments develop antennal appendages, suggesting that a gene(s) has been deleted that acts to distinguish trunk from head. There is no evidence that beetles have a homologue of the segmentation gene fushi tarazu of similar genomic location and function. On the basis of the genetic tractability, convenient genome size and organization of Tribolium, and its relatively long phylogenetic divergence from Drosophila (>300 million years), we have integrated developmental genetic and molecular analyses of the HOM-C. We isolated about 70 mutations in the complex representing at least six complementation groups. The homeotic phenotypes of adults and lethal embryos lead us to believe that these beetle genes are homologous with the Drosophila genes indicated in Fig. 1 (see text).

Animals↗

PubMed1991

Multicenter clinical trial of mitoxantrone in non-Hodgkin's lymphoma and Hodgkin's disease.

In this phase II multicenter trial, the efficacy and safety of mitoxantrone (Novantrone; Lederle Laboratories, Wayne, NJ) were evaluated in the treatment of 206 patients with relapsed non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) previously treated with other agents. Sixty-nine percent of the patients had received prior therapy with doxorubicin. The patients received 14 mg/m2 of mitoxantrone every 3 weeks. Nineteen (12%) of the NHL patients and two (7%) of the HD patients had complete responses (CRs). The combined CR and partial response (PR) rates were 37% (60 of 163) for NHL patients and 36% (10 of 28) for HD patients; the median duration of response was 323 days for NHL patients and 209 days for HD patients. The median survival times were 337 days for patients with NHL and 469 days for patients with HD. The median survival time for patients with low-grade NHL was 589 days compared with 298 days for patients with intermediate-grade NHL and 167 days for patients with high-grade NHL. The median time to treatment failure was 73 days for NHL patients and 98 days for HD patients. The major toxicity was myelosuppression, which was moderate and reversible. Nausea, vomiting, and alopecia were mild. There were two cases of congestive heart failure (CHF) considered related to treatment; both patients had received prior treatment with doxorubicin. In this group of heavily pretreated patients, mitoxantrone was effective and well tolerated. Responses were seen with mitoxantrone in patients who had relapsed after prior therapy with doxorubicin and in patients who had failed to respond to prior therapy with doxorubicin. Mitoxantrone should be evaluated in less heavily pretreated patients and should be considered for incorporation into combination chemotherapeutic regimens for the treatment of malignant lymphoma.

Drug Evaluation↗

PubMed1989

Genetic analysis of the homeotic gene complex (HOM-C) in the beetle Tribolium castaneum.

Our laboratories have undertaken both genetic and molecular studies of the homeotic gene complex (HOM-C) of the beetle Tribolium castaneum, and this paper discusses results from our genetic analyses. We describe here the adult phenotypes and complementation behavior of over 50 new mutations. Many of these homeotic phenotypes resemble those of Drosophila melanogaster, but few precisely parallel the segmental transformations seen in this fly. Analysis of putative loss-of-function mutations affecting the head and thorax suggests that the maxillopedia and Cephalothorax genes most closely resemble proboscipedia and Sex combs reduced of Drosophila. In the abdomen, putative loss-of-function alleles of Abdominal affect a domain corresponding to those of the combined abdominal-A and Abdominal-B genes of Drosophila. In contrast to the situation in flies, Abdominal loss-of-function variants in Tribolium cause anteriorward transformations in A3-A5a, but posteriorward transformations in A5p-A7. The implications of the differences in developmental strategies evolved in Tribolium vs Drosophila are discussed.

Abdomen↗

PubMed1987

Treatment of advanced colorectal carcinoma with actinomycin D, vincristine, methyl-CCNU, and methotrexate.

Twenty patients with advanced colorectal carcinoma were treated with combination chemotherapy consisting of actinomycin D, vincristine, methyl-CCNU, and methotrexate. Fourteen patients had received prior chemotherapy with 5-fluorouracil (5-FU). No complete responses and only one partial response were observed for an overall response rate of 5%. The combination of actinomycin D, vincristine, methyl-CCNU, and methotrexate at the doses and schedule used was of no value in the treatment of patients with metastatic colorectal carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1986

Recombinant gamma interferon in advanced breast cancer: a phase II trial.

Fifteen patients with advanced carcinoma of the breast who had failed prior chemotherapy, were treated with recombinant gamma interferon at a dose of 2mg/m2 (1mg = 2.4 X 10(7) international units) intravenously for five consecutive days every other week. The median patient age was 51 and all patients had a performance status of 0-2 (Karnofsky greater than or equal to 50). Thirteen patients had two or three sites of metastatic disease and seven were estrogen receptor positive. No complete or partial responses were noted. Although some patients had brief periods of stable disease, almost all patients progressed after one or two courses. Only one patient was able to receive six courses of induction therapy and a brief course of maintenance. Flu-like symptoms and nausea were seen in all patients; vomiting and anorexia were frequent. Hepatic toxicity manifested by enzyme elevation was common and was most severe in patients with liver metastases. In this study a highly purified biologically active gamma interferon was not associated with anti-tumor activity in previously treated women with metastatic breast cancer.

Adult↗

PubMed1986

Clinical trial of folinic acid to reduce vincristine neurotoxicity.

In a murine model system, folinic acid demonstrated host-protective properties during administration of repetitive and lethal doses of vincristine (VCR). Subsequently, folinic acid was evaluated in patients receiving VCR during an adjuvant chemotherapy program for stage II carcinoma of the breast. The toxicities, cumulative VCR dosage, and percentage of ideal dosage observed in 18 patients receiving folinic acid have been compared with those observed in 70 patients who previously received VCR without folinic acid in the same chemotherapy program. All patients ideally were intended to receive VCR 1.0 mg/m2 weekly for 6 weeks, with dose modification for neurotoxicity. Treatment patients received folinic acid 800 mg PO daily in three divided doses during the 6-week course. The degree of neurotoxic manifestations of VCR was similar in the treatment and comparison patients. Absent to mild neurotoxicity was observed in approximately 70% of patients in both groups; moderate or greater neurotoxicity occurred in about 30% of patients in both groups. Full dosage (6.0 mg/m2) was attained in 7 (39%) treatment patients and 17 (24%) comparison patients (P = 0.21). The mean percentage of the ideal dosage of VCR was 73.7 +/- 28.7 in patients receiving folinic acid and 76.1 +/- 20.5 in those given only VCR (P = 0.69). Hematologic toxicities were similar in both groups, but nausea occurred more frequently in the folinic acid group. Folinic acid in this dose and schedule afforded no protection from the neurotoxic side effects of VCR.

Adult↗