Permanent URI for this collection


Recent Submissions

Now showing 1 - 20 of 147
  • Item
    Arashi in Black and White
    (May 2024) Lauland, Nicholas; Nicholas Lauland; Nicholas Lauland
    After a great deal of hard work and experimentation, several changes were identified as necessary to enable Arashi to run in Black and White. Additionally, several optimisations were identified to improve the speed on lower performance black and white models.
  • Item
    Sex differences and the effects of stress on neuroanatomical structures involved in modulating inflammatory pain
    (December 2023) Cantu, Daisy Jacqueline; Averitt, Dayna L; Hynds, DiAnna; Lybrand, Zane; Brower, Christopher; Anne Murphy
    Approximately 1 in 5 people suffer from pain worldwide, and women experience more recurrent, severe, and longer-lasting pain. Pain conditions more prevalent in women include migraine, fibromyalgia, irritable bowel syndrome, and temporomandibular joint disorder. Stress can influence pain, and females are more susceptible to stress-exacerbated orofacial pain. As preclinical studies have largely been conducted in males, the mechanisms underlying the effects of stress on pain in females are understudied. Orofacial pain is relayed by sensory neurons in the trigeminal ganglia (TG) that synapse in the brainstem trigeminal nuclear complex (TnC). Ascending pain pathways relay pain signals to the cortex and can initiate descending pain modulation via emotive nuclei in the amygdala and hypothalamus that project to the periaqueductal gray. Our overarching hypothesis is that stress exacerbates orofacial pain to a greater degree in female rats, and there are sex differences in the trigeminal neurocircuitry that transmit somatosensory information to the brain. We utilized behavioral, neuroanatomical, pharmacological, and transcriptomic approaches to investigate sex differences in the effects of stress in a rat model of orofacial pain. We report that stress exacerbates orofacial pain to a greater degree in female rats. Neuroanatomical analyses of the TG and TnC implicate a sex-specific pain mechanism whereby females have dampened GABAergic neurotransmission during stress-exacerbated orofacial pain. In support, pain behaviors were reduced by treatment with a GABAB receptor agonist. Further, when we explored the pain-modulatory projections of the amygdala and hypothalamus to the periaqueductal gray, we uncovered sex differences in their organization and activation by pain, supporting a sexually dimorphic role of emotive brain areas in modulating pain. Overall, our data indicate that stress differentially alters sensory neuron input to the brainstem and is subject to sex-specific descending modulation from emotive centers in the brain. We postulate that women experiencing stress-exacerbated orofacial pain would benefit from a pain management regimen that includes a pharmacological intervention to boost GABA signaling concomitant with interventions that manage stress. Lastly, our transcriptomics data may indicate novel pain therapeutic targets related to the extracellular matrix, which may contribute to the effects of stress on pain chronification in the trigeminal system.
  • Item
    The role of Arginyltransferase 1 in body weight homeostasis
    (August 2023) Alkhatatbeh, Mosleh Ahmed 1977-; Brower, Christopher; Conrad-Webb, Heather; Mills, Nathaniel; Averitt, Dayna L; Na, Elisa
    Previous studies reported that systemic deletion of Arginyltransferase 1 (ATE1) in mice results in dramatic fat loss and resistance to diet-induced obesity. However, the mechanisms through which ATE1 influence energy metabolism remain unclear. Here, we investigated the hypothalamic role of ATE1 by examining the effects of the anorectic hormone leptin in wild type (WT) and ATE1-knockout (ATE1-KO) mice maintained on a normal chow diet, or a high fat diet. We found that on both diets, ATE1-KO mice weighed significantly less than WT mice despite consuming more food (hyperphagia). We also found that, similar to WT mice on normal chow, ATE1-KO mice remain responsive to leptin on NC. However, ATE1-KO mice had significantly lower circulating plasma leptin than wild type mice on both diets. This explains (at least in part) their hyperphagia. Interestingly, we also found that leptin reduces the expression of ATE1 in the hypothalamus, indicating that decreased ATE1 activity may be a component of the Leptin regulatory network driving a lean phenotype. In contrast to normal chow, we found that ATE1-KO mice became leptin resistant on high fat diet. Remarkably, we found that the loss of Ate1 gene function reverses high fat diet-induced obesity. Collectively, these results strongly suggest that the inhibition of ATE1 may offer an effective therapeutic strategy to combat obesity.
  • Item
    Estrogen and progesterone protect against the inhibitory effects of restraint stress
    (2003-08) White, Stacy; Uphouse, Lynda; Knesek, John; Rudick, Michael; Mills, Nathaniel; Gross, G.
    The effects of restraint stress on lordosis behavior were examined in ovariectomized (ovx), hormone-primed rats and in proestrous rats. In the first experiment progesterone (P) dose-dependently reduced the female rat's response to restraint. Ovx rats were primed with 10 μg estradiol benzoate (EB) followed 48 hr later with various doses of progesterone or sesame seed oil (oil). At 5 min after restraint, rats that were given oil or 2.5, 5.0, or 10 μg progesterone and restrained for 5 min showed a decline in lordosis behavior. By 10 min after restraint lordosis had increased; however at no time did the lordosis to mount (L/M) ratios (number of lordosis responses by the female divided by the number of mounts by the male) of rats given 25 μg or higher doses of progesterone decline. In the second experiment EB also acted dose-dependently to decrease the lordosis-inhibiting effects of restraint stress. Ovx rats were hormonally primed with various doses of EB followed 48 hr later with 250 μg P. An additional group received 50 μg EB and oil. The lordosis behavior of restrained rats given 0.5, 1.0, or 2.5 μg EB was reduced 5 min after restraint. This reduction in lordosis behavior lasted for 5 min, but by 10 min, L/M ratios had increased. In the third experiment, physiological levels of hormones protected against a stress-induced decline in lordosis behavior. Proestrous rats showed no decline in lordosis after 5 to 60 min of restraint. In the final experiment, after intraperitoneal treatment with ketanserin tartrate (ketanserin), 5 min of restraint reduced lordosis behavior of proestrous rats. Every rat given 1.0 mg/kg ketanserin and restrained for 5 min showed a decline in lordosis behavior by 5 min after restraint. With 0.50 or 0.75 mg/kg ketanserin, L/M ratios of proestrous rats were not reduced by 5 min of restraint. In conclusion these data are consistent with the suggestions that estrogen and progesterone contribute to facilitation of lordosis behavior and that 5-HT2A/2C receptors may attenuate the disruptive effects of stress.
  • Item
    Role Of G1P3-Induced Mitochondrial Reactive Oxygen Species In Cancer Cell Migration
    (May 2023) Davenport, Anne M 1968-; Hynds, DiAnna; Averitt, Dayna L; Hanson, Laura; Cheriyath, Venugopalan; Anderson, Mary; Hanson, Laura; Anderson, Mary; Cheriyath, Venugopalan
    Breast cancer remains the second leading cause of cancer-related deaths among U.S women with metastasis accounting for ˃ 90% of those deaths. G1P3 (IFI6/ISG6-16) is an interferon-stimulated gene encoding a 13 kDa protein with pleiotropic functions. We and others characterized G1P3 as an anti-apoptotic protein located in the mitochondria with a role in cancer progression and metastasis. In accordance with its mitochondrial location, ectopically expressed G1P3 in breast cancer cells (MCF-7G1P3), resulted in elevated levels of mitochondrial reactive species (mtROS) and remodeled actin, potentiating augmented migration. Both scavenging of mtROS and down-regulation of G1P3 expression significantly reduced the migration of MCF-7G1P3 cells. Comparative gene expression analysis identified the upregulation of Caveolin 1 (CAV1), a regulator of wound healing, by 4-fold (p ≤ 0.05) in MCF-7G1P3 cells. Knock-down of CAV1 with small interfering RNA (siRNA) resulted in reduced migration (p ≤ 0.05) and filopodia formation (p ≤ 0.01) in MCF-7G1P3 cells compared to MCF-7Vector cells. Considering filopodia is the predominant migratory structure in MCF-7G1P3 cells and CDC42 is a regulator of filopodia formation and can mediate cell motility, its role in cell migration was assessed. Relative to MCF-7Vector cells, suppression of CDC42 expression significantly reduced migration in MCF-7G1P3 cells (p ≤ 0.05). In G-Lisa assays, MCF-7G1P3 cells had increased GTP-bound CDC42 compared to MCF-7Vector cells which could be reversed with knockdown of Caveolin 1 and G1P3, as well as scavenging of mtROS with MitoTEMPO. In agreement with G1P3’s pleiotropic functions, in confocal microscopy studies, G1P3-FLAG co-occurred with mitochondria as well as organelles of the endomembrane system, including trans-Golgi, lysosomes, endoplasmic reticulum and endosomes. In particular, 52% of G1P3-FLAG co-occurred with RAB5 positive endosomes. RAB5 has been reported to locate to the mitochondria during events of cell stress. In MCF-7G1P3 cells, RAB5 co-occurred with mitochondria ~1.9-fold more than MCF-7Vector cells suggesting that RAB5 may play a role in conferring cell survival in MCF-7G1P3 cells. In conclusion, this study demonstrates that elevated mtROS generated in MCF-7G1P3 cells can alter gene expression to mediate formation of actin structures and augmented migration and metastatic potential in breast cancer cells.
  • Item
    Analyzing a calcium-dependent UV response that results in a global chromatin compaction in mammalian cells
    (May 2023) Sinha Roy, Rituparna; Bergel, Michael; Gumienny, Tina L; Everts, Helen B; Brower, Christopher; Conrad-Webb, Heather
    Genomic integrity is challenged every day by both endogenous and exogenous stresses. Once DNA gets damaged, a series of events follow, starting with recognizing the damage by accessing it, then processing and repairing the damaged DNA, and eventually restoring the lesion area to its pre-damage state. However, the structural change in the global chromatin in response to UV radiation and the etiology of these changes are not well known. To visualize a global chromatin structural changes upon UVB radiation, we used a fluorometric detection approach. We observed large-scale chromatin compaction immediately after UVB radiation in mouse embryonic fibroblasts, human cervical cancer cells (HeLa), and primary human epidermal melanocytes (HEMs). Using immunofluorescence we also demonstrated that UVB-induced chromatin compaction protects DNA from further UV damage. Using confocal microscopy, we demonstrated cellular calcium influx after UV radiation without external retinal addition. Our RNA-seq data identified two G-protein coupled receptors (GPCRs), SSTR4 and P2RY6, associated with calcium signaling, whose expression was upregulated after UVB radiation in HEMs. Chemical inhibition of P2RY6 and IP3 receptors resulted in a significant reduction in calcium influx and chromatin compaction after UV irradiation of cells. Inhibition on other candidate calcium channel, TRPA1, which mediates UVR-induced calcium influx and early melanin synthesis, did not lead to significant inhibition of chromatin compaction in HEMs after UVB radiation. Based on these findings, we propose that a non-retinal UVB phototransduction pathway is involved in an increase in intracellular calcium triggered by the opening of IP3 receptors which leads to activation of the P2RY6 receptor and then further Ca2+ influx. This increase in cellular Ca2+ concentration leads to an increase in nuclear chromatin compaction, which has a DNA protective role. We suggest that SSTR4 maintains the steady state of calcium by reducing the calcium level after UVB-induced calcium surge in primary human epidermal melanocytes. RNA-seq data revealed that the highest number of genes that upregulated was at 4 hours, and the lowest number of genes upregulated was at 20 minutes after UVB radiation. We suggest that UV-induced chromatin compaction reduces gene expression, and as time progresses, local unfolding of chromatin happens, which allows more gene to be expressed. However, some genes seem to be overexpressed despite the immediate global chromatin compaction and the general gene repression that follows UV radiation. This finding suggests that there are some mechanisms to keep the activation of essential genes after UV irradiation, despite the general gene repression. A detailed understanding of the molecular mechanisms that allow human skin cells to detect UV radiation and respond by compacting the chromatin and protecting the DNA will aid in the search for novel therapeutics to reduce sun-inflicted carcinogenesis.
  • Item
    Plasmid contains unique Helicobacter Pylori insertion sequence IS605
    (1998-08) Burnham, Kara; McIntire, Sarah A.; Knesek, John; Rudick, Michael; Conrad-Webb, Heather; Benjamin, Robert
    Helicobacter pylori is a human gastric pathogen that causes chronic gastritis, peptic ulcer disease and gastric adenocarcinoma. Other pathogenic bacteria, including Salmonella and Escherichia, contain stretches of sequence that encode pathogenicity genes, and are referred to as pathogenicity islands (PAI); a 40 kbp chromosomal PAI occurs in pathogenic strains of H. pylori. IS605, an insertion sequence unique to H. pylori is found in the PAI of some isolates and is thought to be involved in the deletion formations that are noted in these strains. Plasmids have been speculated to be responsible, in part, for the rearrangements of the H. pylori PAI. In this study, we describe a 13 kbp plasmid, pHPM186, which contains two copies of IS605. In addition, pHPM186 carries 1.6 kbp of DNA that show strong sequence identity to region 86 of the H. pylori chromosome, which encodes a PARA protein and 2 hypothetical proteins of unknown functions. Also pHPM 186 has a replication gene (repA) with strong sequence identity to repA genes found in pHPM180, pHPM179 and pHel. The sequence analysis of pHPM186 provided direct evidence that portions of the H. pylori chromosome can be carried by plasmids, making these plasmids possible vehicles for movement of chromosomal DNA between H. pylori strains. Creation of a shuttle vector between H. pylori and E. coli was also attempted in this study. Ligations of the repA region of pHPM186 and a kanamycin resistance gene were transformed into both E. coli and H. pylori. Transformants were recovered only when F$\sp+$ strains of E. coli were used as recipients. Two different sizes of recombinants were isolated that were resistant to kanamycin, but in both the repA region was rearranged. Small H. pylori transformants were initially recovered, but they failed to grow. Attempts to create a shuttle vector showed that the repA gene from H. pylori is not maintained in E. coli, it appears to undergo vast rearrangement. These results provide evidence that a creation of a shuttle vector between this two strains is not possible using this type of recombinant construct.
  • Item
    Effects of protein kinase C inhibitor on 5-HT1A and 5-HT2A/2C receptor interaction in the mediobasal hypothalamus
    (2005-12) Selvamani, Amutha
    Activation of 5-HT1A receptors within the mediobasal hypothalamus (MBH) inhibits female rat lordosis behavior and coinfusion with 5-HT 2A/2C receptor agonists attenuates this inhibition. The mechanism by which 5-HT2 receptors mediate the attenuation of 5-HT1A mediated inhibition of lordosis behavior is unknown. 5-HT1A and 5-HT2 receptors are coupled to Gi/o/z and Gq/11 proteins, respectively. It has been suggested that 5-HT2 receptors can induce heterologous desensitization via a protein kinase C (PKC)-induced phosphorylation of 5-HT 1A receptors. This investigation tests the hypothesis that PKC inhibitors can attenuate the ability of 5-HT2 receptor agonists to reduce the lordosis-inhibiting effects of 5-HT1A receptor agonists. In the first experiment, ovariectomized Fischer rats, hormonally primed with 10 μM estradiol benzoate and 500 μM progesterone, received bilateral MBH infusion with the 5-HT1A receptor agonist, 200 ng (±)-8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), or 200 ng 8-OH-DPAT, plus 2000 ng (+/-)1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2A/2C receptor agonist. DOI was able to attenuate the lordosis inhibiting effects of 8-OH-OH-DPAT. In the second experiment, following hormonal priming, rats were preinfused with either water or 1.0 x 10-1 nmol of the PKC inhibitor, bisindolylmaleimide I HCl (BIM), 30 min or 90 min before infusion with 8-OH-DPAT or with 8-OH-DPAT plus DOI. BIM prevented the DOI mediated attenuation of 8-OH-DPAT mediated inhibition. Varying doses of BIM (1.0 x 10-1 to 1.0 x 10-7 nmol) were used 90 min prior to infusion with 8-OH-DPAT plus DOI in order to see if BIM had a dose-dependent effect on DOI mediated attenuation. The data suggest that BIM dose dependently attenuated DOI's effect. The results of the present study suggest that PKC might play a role in DOI mediated attenuation of lordosis behavior.
  • Item
    Alterations in cerebellar protein synthesis in propylthiouracil-induced hypothyroid rats
    (1991-05) Jaworski, Diane
    Thyroid hormones play an important role in the regulation of gene expression and cerebellar development in the rat. The drug propylthiouracil was used to disrupt thyroid hormone synthesis. This permitted investigation of gene expression under three different states of hormonal deprivation: early in development (PTU 1), late in development (PTU 2), and continual deprivation (PTU 3). The effects of these deprivations on some aspects of the synthesis of two proteins known to be affected by T$\sb3$, apolipoprotein E (apo E) and transferrin (T$\sb{\rm f}$), were investigated. Thyroid hormone's permissive role on growth and development, morphological features as well as body and organ weights were analyzed and found to be significantly reduced in the hypothyroid state. The development of cerebellar cortical strata and cellular morphology was altered by prenatal, as well as postnatal PTU administration. To establish cerebellar synthesis of apo E and T$\sb{\rm f}$, total RNA was extracted, poly A$\sp+$ RNA isolated and translated in an in vitro reticulocyte lysate system. The specific proteins were immunoprecipitated and analyzed by SDS-PAGE. To correlate these results with the amounts of mRNA's for apo E and T$\sb{\rm f}$, northern hybridization was performed. Both apo E and T$\sb{\rm f}$ levels synthesized in vitro with RNA from control animals increased as development proceeded, with apo E produced in greater quantity. While hepatic apo E synthesis increases in the hypothyroid state (presumably as a result of regulation at the transcriptional level), cerebellar apo E translatable mRNA levels were not affected by PTU treatment. Like hepatic T$\sb{\rm f}$, cerebellar T$\sb{\rm f}$ levels were substantially reduced in the hypothyroid state, as compared to control values. Developmentally, apo E mRNA levels declined, while T$\sb{\rm f}$ mRNA levels and T$\sb{\rm f}$ synthesized in vitro were parallel in control animals. PTU 1 treated animals, in which free T$\sb3$ in the circulation increased after PN day 20, demonstrated increases in both apo E and T$\sb{\rm f}$ mRNA levels at the same time point. It appears that the regulation of apo E and T$\sb{\rm f}$ mRNA levels differ from each other within the cerebellum and may be regulated differently from those of the liver. The increase in in vitro protein synthesis and mRNA levels in PTU 1 treated animals may be a result of developmental recovery, rather than specific T$\sb3$ mediated gene regulation.
  • Item
    Studies of antibiotic resistant mutants of Bacteroides Fragilis obtained by Cs-137 ionizing radiation
    (1986-05) Azghani, Ali
    The genus Bacteroides is an obligate anaerobic bacillus normally found in the upper respiratory tract, the colon, and the genitourinary system. The project reported here was undertaken because of the high frequency of hospital infections attributed to B. fragilis, and the increased resistance of the bacteria to commonly used antibiotics. Cs-137 gamma irradiation was used to induce antibiotic resistant mutants in B. fragilis in the presence of Escherichia coli B/r membrane fragments, employed as reducing agent. Based on a dose-survival curve, an effective radiation dose of 1.54 x 10('4)R (3.99 C/Kg) was used to induce mutations to rifampicin and tetracycline resistance in the test organism. The antibiotic resistant mutants of B. fragilis were utilized to reveal the mechanism by which this group of organisms becomes resistant to select chemotherapeutic agents. Studies on tetracycline resistant mutants of B. fragilis isolated after irradiation, suggest that the resistance to this antibiotic is associated with the outer membrane permeability. The difference in inhibitory action of rifampicin on RNA polymerase activity, from rifampicin sensitive and resistant strains of B. fragilis, reveals that this enzyme is a possible suitable target for inhibition of bacterial growth in anaerobes by rifampicin.
  • Item
    Assessment of the role of testosterone in the rat gonads: Morphometrical and cytochemical analysis
    (1996-12) Shuttlesworth, Gladis
    Rat testes are composed of somatic cells, primarily Sertoli (SC), myoid (MC) and Leydig cells (LC), and germinal epithelium which gives rise to spermatozoa. Sertoli, myoid, and Leydig cells have androgen receptors, of which Sertoli and myoid cells are thought to be primarily responsive to testosterone. Adjacent to Sertoli and myoid cells are Leydig cells which are the primary source of testosterone (T). The aim of this study is to evaluate the effects of T on testicular somatic cell morphology and changes in protein synthesis profiles, using prenatally irradiated male rats (devoid of germ cells) that are, thus, Sertoli-cell enriched (SCE). Mature SCE rats were treated with Leuprolide (Leupr.) a GnRH agonist, for six weeks to prevent release of LH and FSH from the pituitary, thus, indirectly blocking T production from Leydig cells in the absence of LH. Some SCE rats were treated with testosterone propionate (T.P.) or in combination with Leupr. Testis weight (with and without tunica albuginea) of Leupr. treated groups were reduced to 53% of SCE controls. Seminiferous tubule diameter of Leupr. treated animals was reduced to 70% of the control. Neither testicular weight not tubule diameter were maintained by T replacement in Leupr. treated animals. Testosterone levels were reduced to 30% of SCE controls with Leupr. Androgen replacement with or without Leupr. increased T levels 17 and 13 fold respectively. With Leupr., Leupr. + T.P., or T.P. alone there was a two fold decrease of LH concentration as compared to the SCE control. FSH levels of groups treated with Leupr. alone and in combination with T.P. showed 94% and 81% higher and lower values, receptively, when compared to SCE controls. Leydig cells showed a severe morphological change in the Leupr. treated group and interstitial tissue had an abundance of unidentified cells. Myoid and Sertoli nuclear morphology was unaltered and no statistical difference in SC numbers were observed. Protein profiles of the testicular tissue were analyzed using SDS-PAGE. A newly synthesized protein (36kDa) was secreted into the medium with Leupr. treatment. This protein was not observed in control, or in T.P. treated animals, but it was found occasionally in the Leupr. + T.P. treated group. Results obtained in this study appear to indicate a direct effect of Leuprolide in somatic cell morphology and in changes of the protein synthetic profile.
  • Item
    Cloning and DNA sequence analysis of a plasmid from Helicobacter pylori
    (1994-08) Minnis, Jennifer
    Helicobacter pylori is a pathogenic bacterium that resides in the gastric epithelium of some individuals and is widely regarded as a cause of type B gastritis and duodenal ulcer. Many bacterial species contain plasmid DNA which encodes virulence factors. Little is known about the plasmid DNAs found in some isolates of H. pylori. The purpose of this study was to clone a plasmid from Helicobacter pylori and to determine and analyze the DNA sequence. A 3.5 kb plasmid (pHPM180) was isolated from a strain of H. pylori (HPM180) obtained from a patient with inactive duodenal ulcer. The plasmid was successfully cloned in both orientations in E. coli $\rm DH5\alpha F\sp\prime$ using the M13mp18 vector, and the DNA sequence was determined using the dideoxy chain termination method. Analysis of the sequence was performed with DNAsis and PC-Gene software packages. Two open reading frames (ORFs) were identified. ORF1 translated to 463 amino acids and a putative polypeptide with a molecular weight of 54517. ORF2 translated to 240 amino acids with a molecular weight of 28142. Ribosome binding consensus sequences were identified upstream from both ORFs, and promoter consensus sequences were identified upstream from ORF1. A 232 base pair direct repeat was also identified in the DNA sequence of pHPM180. Extensive DNA sequence homology was found between pHPM180 ORF1 and a 684 base pair HindIII fragment of a 7.2 kb H. pylori plasmid. Additionally, sequence identity was found between 142 bases in a 200 base pair overlap of pHPM180 DNA and a segment of H. pylori pHPK255; a plasmid that encodes a Gram-positive type replication protein. However, the area of homology was not contained within the ORF of pHPK255. A ribonuclease protection assay determined that ORF1 is transcribed in H. pylori HPM180.
  • Item
    Induction of viral resistance in plants by dsRNA interference
    (2005-12) DeLany, Thomas
    Double-stranded RNA (dsRNA) has been shown to promote interference of gene expression of endogenous genes that contain homologous sequences. This interference is referred to as post-transcriptional gene silencing or PTGS. PTGS appears to be a nucleotide sequence specific defense mechanism that can target both endogenous and exogenous messenger RNA (mRNA). PTGS employs a yet unexplained RNA degradation mechanism. In this research, in vitro synthesized dsRNA homologous to two different segments of the genome of the bean common mosaic necrosis virus (BCMNV) was applied to bean plants to determine if the dsRNA affected the susceptibility of the plant to BCMNV infection. The results indicated that the application of dsRNA reduced the number of local lesions per leaf and reduced plant death by approximately 20%. Using dsRNA that expressed homology to different regions of BCMNV did not result in any difference in the ability of dsRNA to inhibit viral replication. Within the parameters of concentration of dsRNA used, no difference in the effectiveness of viral inhibition of the dsRNA was observed. A relationship was observed between the time interval between the application of dsRNA and viral local lesions. The greater reduction of local lesions was observed on leaves that had the greater time interval between the application of the dsRNA and viral inoculation. Systemic viral resistance was observed when the primary leaf was treated with dsRNA and trifoliate leaf was inoculated with the virus. No viral resistance was observed in plants that developed from seeds produced by dsRNA treated plants that survived viral inoculation.
  • Item
    Effects of fluoxetine on estrous cycle and sexual behavior in female rats
    (2007-12) Sarkar, Jhimly
    Although highly effective for treatment of depression, antidepressants, such as fluoxetine (Prozac®), produce sexual dysfunction in a substantial number of patients. Mechanisms responsible for such sexual dysfunction were the focus of these studies. In a previous experiment, when female Fischer rats were treated daily with 10 mg/kg fluoxetine, both the estrous cycle and sexual behavior were disrupted. These results contrast with prior findings from which it has been suggested that fluoxetine does not disrupt estrous cyclicity. The current studies were designed to investigate explanations for the different outcomes and identify mechanisms for the cycle disruption. Fischer female rats received 15 days of 10 mg/kg fluoxetine with or without a 5 min daily exposure to a sexually active male. Male exposure delayed the onset of cycle disruption. Sprague-Dawley females were treated daily with 10 mg/kg fluoxetine to examine the generality of prior findings. Cycle disruption, though present, was less severe than in Fischer rats. A pair-fed group was added to the protocol to determine if reduced food intake contributed to the fluoxetine-induced sexual disruption in Fischer females. Pair-feeding mimicked the effect of fluoxetine on the estrous cycle. In the next experiment, we questioned if hormonal priming could prevent the effect of fluoxetine on sexual behavior as measured by the lordosis reflex. In spite of hormonal priming, fluoxetine still reduced lordosis behavior. However, the magnitude of disruption was less than that seen in intact females. Finally we examined the effects of repeated fluoxetine treatment on serum luteinizing hormone (LH) both in ovariectomized and intact rats. Fluoxetine treatment failed to show any significant effect on serum LH. These experiments reinforce the possibility that a fluoxetine-induced disruption of the estrous cycle contributes to the drug-induced sexual dysfunction.
  • Item
    Strain differences in 8-OH-DPAT-induced hyperphagia: Modulation by female gonadal hormones
    (2002-12) Shaheen, Farzana; Uphouse, Lynda; Rudnick, Michael; Droge, Michael; Maier, Camelia; Schwaim, Fritz; Gross, Gunter