Bacterial Stripe of Hog Millet Caused by Acidovorax avenae subsp. avenae, a New Disease in Korea

In July 2011, bacterial stripe was observed on a commercial field of hog millet (Panicum miliaceum L.) in Chuncheon, Korea, with a disease incidence of 37% in the field. Symptoms on leaves included reddish-brown, long, narrow stripes that varied in length and were sharply delineated by uninfected adjacent vascular bundles. Eleven bacterial isolates (BC3107, BC3214 to BC3223) were recovered on trypticase soy agar from lesions surface sterilized in 70% ethanol for 1 min. The isolates, all obtained from different plants, were gram negative, oxidase positive, aerobic rods with two to four flagella. The isolates produced circular, cream-colored, nonfluorescent, butyrous colonies with entire margins on King's B medium. Using the Biolog Microbial Identification System, Version 4.2 (Biolog Inc., Hayward, CA), the isolates were identified as Acidovorax avenae subsp. avenae with Biolog similarity indices ranging from 0.52 to 0.72 after 24 hr. Characters for differentiating between Acidovorax spp. were tested according to Schaad et al. (2). The isolates were positive for gelatin liquefaction, nitrate reduction, lipase production, utilization of D-mannitol, sodium citrate, and alkaline in litmus milk. The isolates were negative for utilization of D-arabitol and did not amplify with PCR primer sets Aaaf5, Aaaf3/Aaar2, and Aacf2/Aacr2. Colonies were V^-, V⁺, and V⁺ for utilization of D-fucose, maltose, and ethanol, respectively. Regions of the 16S rRNA (rrs) and the IGS were sequenced to aid in the identification of the isolates using reported PCR primer sets (1,4). A 1,426 bp fragment of the rrs region shared 100% similarity with all strains of A. avenae available in GenBank. Pathogenicity tests were separately performed for the 11 isolates in different greenhouses located in Suwon (National Academy of Agricultural Science), and Chuncheon (Gangwondo Agricultural Research and Extension Services) in Korea. Pathogenicity was confirmed by clip inoculation with sterilized scissors dipped into cell suspensions containing 10⁵ CFU/ml on three 8-day-old leaves of hog millet (two plants per isolate), rice (Oryza sativa L. cv. Hopyeong), and sweet corn (Zea mays L. cv. Daehak) in a greenhouse maintained at 28 to 32°C and 90% relative humidity. The isolates induced similar symptoms as those originally observed on hog millet 5 days after inoculation. No symptoms were observed on the control plants (hog millet, rice, and sweet corn), which were clipped with scissors dipped in sterilized distilled water. The identity of bacteria reisolated from the stripes on inoculated leaves was confirmed by analyzing sequences of the 16S-23S rRNA intergenic spacer region (IGS) (1). On the basis of physiological, pathological, and sequence data, the isolates were identified as A. avenae subsp. avenae. To our knowledge, this is the first report of bacterial stripe of hog millet caused by A. avenae subsp. avenae in Korea. The spread of the bacterial disease is expected to have a significant economic impact on hog millet culture in the fields of Gangwon Province in Korea. Nucleotide sequence data reported are available under accession numbers JQ743877 to JQ743887 for rrs of BC 3207 and BC3214 to BC3223, and JQ743877 to JQ743887 for IGS of BC3207 and BC3214 to BC3223. References: (1) T. Barry et al. The PCR Methods Appl. 1:51, 1991. (2) N. W. Schaad et al. Syst, Appl. Microbiol. 31: 434, 2008. (3) K. Tamura et al. Mol. Biol. Evol. 28:2731, 2011. (4) W. G. Weisburg et al. J. Bacteriol. 173: 697, 1991.

First Report of Zonate Leaf Spot of Glycine max Caused by Cristulariella moricola in Korea

Soybean (Glycine max (L.) Merr.) is native to East Asia including Korea and is widely grown and consumed as an edible seed. In August 2011, following a prolonged period of cool and moist weather, zonate leaf spots were observed in local soybean (cultivar unknown) planted in a mountainous area of Goseong, central Korea. A voucher specimen was collected and entered at the Korea University herbarium (KUS-F26049). Initial symptoms included grayish green-to-grayish brown spots without border lines. As the lesions enlarged, they coalesced, leading to leaf blight and premature defoliation. Sporophores on the leaf lesions were dominantly hypophyllous, rarely epiphyllous, solitary, erect, easily detachable, and as long as 750 μm. The upper portion of the sporophores consisted of a pyramidal head that was ventricose, 275 to 500 μm long, and 80 to 160 μm wide. The fungus was isolated from leaf lesions and maintained on potato dextrose agar (PDA). Sclerotia were produced on PDA after 4 to 5 weeks at 18°C without light, but conidia were not observed in culture. The morphological and cultural characteristics were consistent with those of Cristulariella moricola (Hino) Redhead (2,3). An isolate was preserved in the Korean Agricultural Culture Collection (KACC46401). Genomic DNA was extracted with the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 453 bp was deposited in GenBank (Accession No. JQ036182). A BLAST search in GenBank revealed that the sequence showed an exact match with that of C. moricola from Acer negundo (JQ036181) and >99% similarity with that of Grovesinia pyramidalis, teleomorph of C. moricola from Juglans sp. (Z81433). To determine the pathogenicity of the fungus, sporophores with the pyramidal head were carefully detached from a lesion on the naturally infected leaflet with fine needles. Each sporophore was transferred individually onto four places of six detached healthy soybean leaflets. The leaflets were placed in humid chambers at 100% relative humidity and incubated at 16 to 20°C (4). Symptoms were observed after 2 days on all inoculated leaflets (one to four lesions/leaflet). The lesions enlarged rapidly and reached ~20 mm diameter in a week. A number of sporulating structures and immature sclerotia were formed on the abaxial surface of the leaf 2 weeks after inoculation. The pathogen was reisolated from lesions on the inoculated leaflets, confirming Koch's postulates. No symptoms were observed on the control leaflets kept in humid chambers for 2 weeks. C. moricola was known to cause zonate leaf spots and defoliation on a wide range of woody and annual plants (1), but not on G. max. To our knowledge, this is the first report of Cristulariella infection in cultivated soybeans. Since the infections may be limited to the mountainous area with low night temperature and high humidity, economic losses seem to be negligible. However, the disease could be a potential threat to the safe production of soybeans in areas with prolonged periods of cool and moist weather. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.arsgrin.gov/fungaldatabases/ , January 7, 2012. (2) H. B. Lee and C. J. Kim. Plant Dis. 86:440, 2002. (3) S. A. Redhead. Can. J. Bot. 53:700, 1975. (4) H. J. Su and S. C. Leu. Plant Dis. 67:915, 1983.

Systems biology and epigenetic gene regulation

Epigenetics is the study of regulatory mechanisms that are not accompanied by the action of genetic elements. Recently, a system-wide extension of epigenetics has been driven by the rapid evolution of genomics technology. This means not simply profiling multiple genes together as gene expression microarrays, but also factoring in the crosstalk among various epigenetic components and extending our focus to relatively uncharted genomic areas, including intergenic and intragenic regions. Although this exciting extension provides many interesting research topics as described in this review, the future expansion of epigenomics to cover multiple samples will offer an even more profound opportunity for systems biology research.

Imaging brain regional and cortical laminar effects of selective D3 agonists and antagonists

RATIONALE

Dopamine D3 receptors (D3R) may be important therapeutic targets for both drug abuse and dyskinesias in Parkinson's disease; however, little is known about their functional circuitry.

OBJECTIVES

We wished to determine if D3R antagonists SB-277011 and PG-01037 and D3R-preferring agonist 7-OH-DPAT are D3R selective in vivo. We further wished to characterize the response to D3R drugs using whole brain imaging to identify novel D3R circuitry.

METHODS

We investigated D3R circuitry in rats using pharmacologic MRI and challenge with selective D3R antagonists and agonist at various doses to examine regional changes in cerebral blood volume (CBV). We compared regional activation patterns with D2R/D3R agonists, as well as with prior studies of mRNA expression and autoradiography.

RESULTS

D3R antagonists induced positive CBV changes and D3R agonist negative CBV changes in brain regions including nucleus accumbens, infralimbic cortex, thalamus, interpeduncular region, hypothalamus, and hippocampus (strongest in subiculum). All D3R-preferring drugs showed markedly greater responses in nucleus accumbens than in caudate/putamen consistent with D3R selectivity and contrary to what was observed with D2R agonists. At high doses of D3R agonist, functional changes were differentiated across cortical laminae, with layer V-VI yielding positive CBV changes and layer IV yielding negative CBV changes. These results are not inconsistent with differential D1R and D3R innervation in these layers respectively showed previously using post-mortem techniques.

CONCLUSIONS

MRI provides a new tool for testing the in vivo selectivity of novel D3R dopaminergic ligands where radiolabels may not be available. Further, the functional D3R circuitry strongly involves hypothalamus and subiculum as well as the limbic striatum.

Caudal epidural block in children: comparison of needle insertion parallel with caudal canal versus conventional two-step technique

This study compared the technique of inserting the needle for caudal epidural blockade in a single pass parallel to the caudal canal versus the conventional technique of approaching the caudal canal with the needle at a steeper angle. Seventy-five patients, aged 0 to 72 months, scheduled for urological surgery were prospectively enrolled in this study. Patients were randomly divided into two groups: a conventional method group (caudal block performed with conventional needle insertion, n=40) and a new method group (needle inserted into the skin at an angle of 200 and into the caudal space without redirection, n=35). Two anaesthetists (A, B) performed the caudal blocks. For anaesthetist A, the mean time required (standard deviation) to perform needle insertion in the conventional method group was 2.2 (0.8) minutes and in the new method group 1.1 (0.7) minutes (P = 0.03). For anaesthetist B the mean time (standard deviation) to perform needle insertion in the conventional method group was 2.1 (1.1) minutes and in the new method group 1.3 (0.8) minutes (P = 0.04). Successful block was considered as first pass placement of the needle in the caudal canal confirmed (after placement) by ultrasound imaging, and the absence of a bloody tap. Subcutaneous placement of the needle after the first attempt occurred in two cases in the conventional method group and three cases in the new method group. Bloody tap occurred in four cases, all in the conventional method group and none in the new method group. When required, the second pass was successful in all cases.

Pharmacologic neuroimaging of the ontogeny of dopamine receptor function

Characterization of the ontogeny of the cerebral dopaminergic system is crucial for gaining a greater understanding of normal brain development and its alterations in response to drugs of abuse or conditions such as attention-deficit hyperactivity disorder. Pharmacological MRI (phMRI) was used to determine the response to dopamine transporter (DAT) blockers cocaine and methylphenidate (MPH), the dopamine releaser D-amphetamine (AMPH), the selective D1 agonist dihydrexidine, and the D2/D3 agonist quinpirole in young (<30 days old) and adult (>60 days old) rats. In adult rats, cocaine (0.5 mg/kg i.v.) or MPH (2 mg/kg) induced primarily positive cerebral blood volume (rCBV) changes in the dopaminergic circuitry, but negative rCBV changes in the young animals. Microdialysis measurements in the striatum showed that young rats have a smaller increase in extracellular dopamine in response to cocaine than adults. The young rats showed little rCBV response to the selective D1 agonist dihydrexidine in contrast to robust rCBV increases observed in the adults, whereas there was a similar negative rCBV response in the young and adult rats to the D2 agonist quinpirole. We also performed a meta-analysis of literature data on the development of D1 and D2 receptors and the DAT. These data suggest a predominance of D2-like over D1-like function between 20 and 30 days of age. These combined results suggested that the dopamine D1 receptor is functionally inhibited at young age.

Detection of increased scyllo-inositol in brain with magnetic resonance spectroscopy after dietary supplementation in Alzheimer's disease mouse models

There is evidence that inositol isomers may help protect against formation of toxic fibrils of Abeta fragments in Alzheimer's disease mouse models. Scyllo-inositol is one of the more promising inositol isomers for the potential treatment of Alzheimer's disease (AD) and can be detected using MRS in human subjects. In this manuscript we demonstrate using MRS, in two different mouse models of AD (APP x PS1 and APP x PS1 x tau), that we could detect increased scyllo-inositol in the hippocampus and frontal cortex in mice fed water supplemented with 16.5 mg/L of scyllo-inositol equivalent to about 3.3 mg/kg/day. We used both brain extracts using solution MRS as well as intact brain tissue using high resolution magic angle spinning (HRMAS) to ensure that any membrane-associated scyllo-inositol would be detected. By brain extracts we detected a 3.0 fold increase in scyllo-inositol in the scyllo-fed AD mice compared to normal diet (p < 0.001). Using HRMAS we detected a 2.2-2.4-fold increase in scyllo-inositol (p < 0.001). Scyllo-inositol treatment was associated with an increase in glutamine in hippocampus. The concentrations of scyllo-inositol were higher in the hippocampus than in the frontal cortex. Mice have a smaller concentration of scyllo-inositol than humans (ca. 100 microM vs. 500 microM in humans). Given the ease with which scyllo-inositol can be measured in human MRS data with high signal to noise ratios, these data suggest that MRS will prove useful for evaluation of inositol treatment trials in AD subjects.

Longitudinal monitoring of motor neuron circuitry in FALS rats using in-vivo phMRI

Amyotrophic lateral sclerosis (ALS) presents challenges for diagnosis and objective monitoring of disease progression. We show, using pharmacologic MRI, that alterations in motor circuitry can be characterized using a passive stimulus in a rat model of familial ALS as a function of symptom progression. Presymptomatic familial ALS rats had a pattern of activation to amphetamine that was statistically indistinguishable from the wild-type controls. In contrast, symptomatic rats showed significantly decreased response in sensorimotor cortex and increased response in M2 motor cortex, caudate/putamen, and thalamus. These results are similar to findings in humans of altered response to motor tasks in ALS. It may be plausible to use a passive amphetamine challenge as a biomarker to assess progression of the disease and efficacy of potential treatments.

Moderate exercise delays the motor performance decline in a transgenic model of ALS

The relationship between exercise and amyotrophic lateral sclerosis (ALS), a neurodegenerative disorder characterized by motor neuron loss, rapidly progressive weakness and early death has been controversial. We studied the effect of a high (HEX) and moderate-level exercise (MEX) on body weight, motor performance and motor neuron counts in the ventral horn of spinal cords in a transgenic mouse model of ALS (G93A-SOD1) that overexpresses a mutated form of the human SOD1 gene that is a cause of familial ALS. These transgenic mice show several similarities to the human disease, including rapid progressive motor weakness from 100 days of age and premature death at around 135 days of age. Mice were exposed to high or mid-level exercise of left sedentary (SED). At 70, 95 and 120 days of age, spinal cords were processed following euthanasia. Motor neurons larger than 15 mum in diameter were counted with a design-based stereological protocol using an optical fractionator probe in the ventral horn of different regions of the cord and compared to wild-type littermates. Moderate exercise delayed the onset of motor deficit by over a week. High exercise slightly but significantly hastened the onset of motor performance deficits. Motor neuron density in the lumbar cord was significantly higher in MEX group compared to SED at 95 days of age. These results show the beneficial effects of moderate exercise on the preservation of motor performance that correlates with higher motor neuron density in the ventral horn of the lumbar spinal cord in G93A mice.

Magnetic resonance spectroscopy of regional brain metabolite markers in FALS mice and the effects of dietary creatine supplementation

We investigated the effects of disease progression on brain regional neurochemistry in a mutant mouse model of familial amyotrophic lateral sclerosis (FALS; the G93A model) using in vivo and in vitro magnetic resonance spectroscopy (MRS). There were numerous changes in the brain spectra that were brain region dependent. At early time points starting around 80 days of age there were increases in brain glutamate. At later time points there were more extensive changes including decreased N-acetyl aspartate and glutamate and increased glutamine, taurine and myo-inositol. The effects of the disease were most severe in spinal cord followed by medulla and then sensorimotor cortex. There were no changes noted in cerebellum as a control region. The effects of creatine supplementation in the diet (2%) were measured in wild-type and FALS animals in medulla, cerebellum and cortex. The increase in brain creatine was largest in cerebellum (25%) followed by medulla (11%) and then cortex (4%), reflecting the ordering of creatine kinase activity. There was a protective effect of creatine on N-acetyl aspartate loss in the medulla at late stages. Creatine supplementation had a positive effect on weight retention, leading to a 13% increase in weight between 120 and 130 days. MRS shows promise in monitoring multiple facets of neuroprotective strategies in ALS and ALS models.

Dopaminergic response to graded dopamine concentration elicited by four amphetamine doses

We studied the metabolic responses to different DA concentrations elicited by four doses of D-amphetamine (AMPH, 0, 0.25, 0.5, 1.0, or 3.0 mg/kg). We compared the degree of DA release (via microdialysis) with striatal cAMP activity and whole brain maps of cerebral blood volume (rCBV) changes (via pharmacological MRI, phMRI).

RESULTS

AMPH increased DA release in the caudate/putamen (CPu) and cAMP activity in the CPu, nucleus accumbens (NAc), and medial prefrontal cortex (mPFC) in a linear dose-dependent manner (P < 0.0001). The cAMP data suggest that, postsynaptically, signal transduction induced by D1 receptor is stronger than that of D2 receptor at the higher doses (1-3 mg/kg). phMRI showed that, while higher doses of AMPH (3 mg/kg (n = 7) and 1 mg/kg (n = 6)) induced significant rCBV increases in the CPu and NAc, the degree of rCBV increase was much smaller with AMPH of 0.5 mg/kg (n = 6). In contrast, AMPH of 0.25 mg/kg (n = 8) induced significant rCBV decreases in the anteromedial CPu and NAc. The sign switch of rCBV in response to AMPH from low to high doses likely reflects the switching in the balance of D2/D3 stimulation vs. D1/D5 stimulation. In conclusion, degree of postsynaptic signal transduction is linearly correlated to the extracellular DA concentration. However, the presynaptic binding may dominate the overall DA innervation at the lower range of DA concentration.

Anti-inflammatory treatment in AD mice protects against neuronal pathology

Prior studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may lower the incidence of Alzheimer's disease (AD) and delay onset or slow progression of symptoms in mouse models of AD. We examined the effects of chronic NSAID treatment in order to determine which elements of the pathological features might be ameliorated. We compared the effects of the NSAIDs ibuprofen and celecoxib on immunohistological and neurochemical markers at two different ages in APPxPS1 mice using measurements of amyloid plaque deposition, Abeta peptide levels, and neurochemical profiles using magnetic resonance spectroscopy (MRS). At 6 months of age, few neurochemical changes were observed between PSAPP mice and WT mice using MRS. Ibuprofen, but not celecoxib, treatment significantly decreased the Abeta(42/40) ratio in frontal cortex at 6 months, but overall amyloid plaque burden was unchanged. Consistent with prior findings in mouse models, at 17 months of age, there was a decrease in the neuronal markers NAA and glutamate and an increase in the astrocytic markers glutamine and myo-inositol in AD mice compared to WT. Ibuprofen provided significant protection against NAA and glutamate loss. Neither of the drugs significantly affected myo-inositol or glutamine levels. Both ibuprofen and celecoxib lowered plaque burden without a significant effect on Abeta(1-42) levels. NAA levels significantly correlated with plaque burden. These results suggest that selective NSAIDs (ibuprofen and possibly celecoxib) treatment can protect against the neuronal pathology.

A robust xenotransplantation model for acute myeloid leukemia

Xenotransplantation of human acute myeloid leukemia (AML) in immunocompromised animals has been critical for defining leukemic stem cells. However, existing immunodeficient strains of mice have short life spans and low levels of AML cell engraftment, hindering long-term evaluation of primary human AML biology. A recent study suggested that NOD/LtSz-scid IL2Rgammac null (NSG) mice have enhanced AML cell engraftment, but this relied on technically challenging neonatal injections. Here, we performed extensive analysis of AML engraftment in adult NSG mice using tail vein injection. Of the 35 AML samples analyzed, 66% showed bone marrow engraftment over 0.1%. Further, 37% showed high levels of engraftment (>10%), with some as high as 95%. A 2-44-fold expansion of AML cells was often seen. Secondary and tertiary recipients showed consistent engraftment, with most showing further AML cell expansion. Engraftment did not correlate with French-American-British subtype or cytogenetic abnormalities. However, samples with FLT3 mutations showed a higher probability of engraftment than FLT3 wild type. Importantly, animals developed organomegaly and a wasting illness consistent with advanced leukemia. We conclude that the NSG xenotransplantation model is a robust model for human AML cell engraftment, which will allow better characterization of AML biology and testing of new therapies.

The blood-brain barrier is intact after levodopa-induced dyskinesias in parkinsonian primates--evidence from in vivo neuroimaging studies

It has been suggested, based on rodent studies, that levodopa (L-dopa) induced dyskinesia is associated with a disrupted blood-brain barrier (BBB). We have investigated BBB integrity with in vivo neuroimaging techniques in six 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesioned primates exhibiting L-dopa-induced dyskinesia. Magnetic resonance imaging (MRI) performed before and after injection of Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) revealed an intact BBB in the basal ganglia showing that l-dopa-induced dyskinesia is not associated with a disrupted BBB in this model.

Efficacy of low-calorie, partial meal replacement diet plans on weight and abdominal fat in obese subjects with metabolic syndrome: a double-blind, randomised controlled trial of two diet plans - one high in protein and one nutritionally balanced

BACKGROUND

Little is known about the relative efficacy of high-protein vs. conventional diet plans that include partial meal replacements on body fat loss in obese subjects with metabolic syndrome.

OBJECTIVE

We aimed to evaluate the efficacy of two low-calorie diets with partial meal replacement plans-a high-protein plan (HP) and a nutritionally balanced conventional (C) plan-on reducing obesity in obese subjects with metabolic syndrome.

DESIGN

In a 12-week, double-blind study, we randomised 75 participants to either the HP- or the C-plan group. We recorded key metrics at 0 and 12 weeks.

RESULTS

The overall mean weight loss was 5 kg in the HP-plan group and 4.9 kg in the C-plan group (p = 0.72). Truncal fat mass decreased 1.6 kg in the HP-plan group (p < 0.05) and 1.5 kg in the C-plan group (p < 0.05), while whole body fat mass decreased 2.5 kg in the HP-plan group (p < 0.05) and 2.3 kg in the C-plan group (p < 0.05). Between-group losses did not differ significantly for truncal (p = 0.52) or whole body (p = 0.77) fat mass. Among subjects with > or = 70% dietary compliance, however, truncal and whole body fat mass decreased more in the HP-plan group (Delta 2.2 kg and Delta 3.5 kg respectively) than in the C-plan group (Delta 1.3 kg and Delta 2.3 [corrected] kg respectively) (p < 0.05).

CONCLUSION

The HP- and C-plans had a similar effect on weight and abdominal fat reduction, but the HP-plan was more effective in reducing body fat among compliant subjects.

Gamma c-signaling cytokines induce a regulatory T cell phenotype in malignant CD4+ T lymphocytes

In this study, we demonstrate that malignant mature CD4(+) T lymphocytes derived from cutaneous T cell lymphomas (CTCL) variably display some aspects of the T regulatory phenotype. Whereas seven cell lines representing a spectrum of primary cutaneous T cell lymphoproliferative disorders expressed CD25 and TGF-beta, the expression of FOXP3 and, to a lesser degree, IL-10 was restricted to two CTCL cell lines that are dependent on exogenous IL-2. IL-2, IL-15, and IL-21, all of which signals through receptors containing the common gamma chain, induced expression of IL-10 in the IL-2-dependent cell lines as well as primary leukemic CTCL cells. However, only IL-2 and IL-15, but not IL-21, induced expression of FOXP3. The IL-2-triggered induction of IL-10 and FOXP3 expression occurred by signaling through STAT3 and STAT5, respectively. Immunohistochemical analysis of the CTCL tissues revealed that FOXP3-expressing cells were common among the CD7-negative enlarged atypical and small lymphocytes at the early skin patch and plaque stages. Their frequency was profoundly diminished at the tumor stage and in the CTCL lymph node lesions with or without large cell transformation. These results indicate that the T regulatory cell features are induced in CTCL T cells by common gamma chain signaling cytokines such as IL-2 and do not represent a fully predetermined, constitutive phenotype independent of the local environmental stimuli to which these malignant mature CD4(+) T cells become exposed.

Heterocyclic Analogues of N-(4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)butyl)arylcarboxamides with Functionalized Linking Chains as Novel Dopamine D3 Receptor Ligands: Potential Substance Abuse Therapeutic Agents

Dopamine D3 receptor antagonists and partial agonists have been shown to modulate drug-seeking effects induced by cocaine and other abused substances. Compound 6 [PG01037, (N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)-trans-but-2-enyl)-4-pyridine-2-ylbenzamide)] and related analogues are currently being evaluated in animal models of drug addiction. In these studies, a discrepancy between in vitro binding affinity, in vivo occupancy, and behavioral potency has been observed. The purpose of this study was to examine (1) modifications of the 2-pyridylphenyl moiety of 6 and (2) hydroxyl, acetyl, and cyclopropyl substitutions on the butylamide linking chain systematically coupled with 2-fluorenylamide or 2-pyridylphenylamide and 2-methoxy- or 2,3-dichloro-substituted phenylpiperazines to measure the impact on binding affinity, D2/D3 selectivity, lipophilicity, and function. In general, these modifications were well tolerated at the human dopamine D3 (hD3) receptor (Ki = 1-5 nM) as measured in competition binding assays. Several analogues showed >100-fold selectivity for dopamine D3 over D2 and D4 receptors. In addition, while all the derivatives with an olefinic linker were antagonists, in quinpirole-stimulated mitogenesis at hD3 receptors, several of the hydroxybutyl-linked analogues (16, 17, 21) showed partial agonist activity. Finally, several structural modifications reduced lipophilicities while retaining the desired binding profile.

In vivo evidence of D3 dopamine receptor sensitization in parkinsonian primates and rodents with l-DOPA-induced dyskinesias

A growing body of evidence indicates a role for D(3) receptors in l-DOPA-induced dyskinesias. This involvement could be amenable to non-invasive in vivo analysis using functional neuroimaging. With this goal, we examined the hemodynamic response to the dopamine D(3)-preferring agonist 7-hydroxy-N,N-di-n-propyl-2 aminotetralin (7-OHDPAT) in naïve, parkinsonian and l-DOPA-treated, dyskinetic rodents and primates using pharmacological MRI (phMRI) and relative cerebral blood volume (rCBV) mapping. Administration of 7-OHDPAT induced minor negative changes of rCBV in the basal ganglia in naïve and parkinsonian animals. Remarkably, the hemodynamic response was reversed (increased rCBV) in the striatum of parkinsonian animals rendered dyskinetic by repeated l-DOPA treatment. Such increase in rCBV is consistent with D(1) receptor-like signaling occurring in response to D(3) stimulation, demonstrates a dysregulation of dopamine receptor function in dyskinesia and provides a potentially novel means for the characterization and treatment of l-DOPA-induced dyskinesia in patients.

Application of MRS to mouse models of neurodegenerative illness

The rapid development of transgenic mouse models of neurodegenerative diseases, in parallel with the rapidly expanding growth of MR techniques for assessing in vivo, non-invasive, neurochemistry, offers the potential to develop novel markers of disease progression and therapy. In this review we discuss the interpretation and utility of MRS for the study of these transgenic mouse and rodent models of neurodegenerative diseases such as Alzheimer's (AD), Huntington's (HD) and Parkinson's disease (PD). MRS studies can provide a wealth of information on various facets of in vivo neurochemistry, including neuronal health, gliosis, osmoregulation, energy metabolism, neuronal-glial cycling, and molecular synthesis rates. These data provide information on the etiology, natural history and therapy of these diseases. Mouse models enable longitudinal studies with useful time frames for evaluation of neuroprotection and therapeutic interventions using many of the potential MRS markers. In addition, the ability to manipulate the genome in these models allows better mechanistic understanding of the roles of the observable neurochemicals, such as N-acetylaspartate, in the brain. The argument is made that use of MRS, combined with correlative histology and other MRI techniques, will enable objective markers with which potential therapies can be followed in a quantitative fashion.

Infection of soybean by cucumber mosaic virus as determined by viral movement protein

To characterize the host range determinant of the soybean strain of Cucumber mosaic virus (CMV) we analyzed a series of pseudorecombinants and chimeric viruses between infectious transcripts from two soybean strains (CMV-SC and CMV-SD) and an ordinary strain (CMV-Y). CMV-Y could not infect soybeans, even locally. Systemic infection of the two soybean-adapted soybean isolates on soybean plants mapped to RNA3. Chimeric RNA3s from between CMV-SC and CMV-Y, and chimeric RNA3s from between CMV-SC and CMV-SD, were made and inoculated onto wild soybean Iwate and soybean cv. Tsurunoko. The 3a region determined the viral systemic movement in the plants. In the wild soybean ecotype Hyougo, cell-to-cell movement of two different CMV soybean strains, one of which infects systemically while the other does not, in the inoculated leaves were almost the same, suggesting that the resistance of soybean operates at the level of long-distance movement. Our results clearly suggest that movement protein is a host determinant of CMV soybean strains.

The complete genome sequence of pepper severe mosaic virus and comparison with other potyviruses

The complete nucleotide sequence of pepper severe mosaic virus (PepSMV) was determined. The viral genome consisted of 9890 nucleotides, excluding a poly (A) tract at the 3' end of the genome. The PepSMV RNA genome encoded a single polyprotein of 3085 amino acid residues, resulting in ten functionally distinct potyviral proteins. The lengths of the 5' nontranslated region (NTR) and the 3' NTR were 164 and 468 nucleotides, respectively. The genome organization of the virus was typical for members of the genus Potyvirus in the family Potyviridae. The coat protein amino acid sequence identity between PepSMV and the other 45 potyviruses ranged from 53.4 to 79.7%. Sequence alignments and phylogenetic analyses of the potyviral polyprotein sequences revealed that PepSMV was the closest to potato virus Y (PVY) and closely related to members of the PVY subgroup. Our genome sequence data clearly confirmed that PepSMV belongs to a separate species in the genus Potyvirus.

Brain hemodynamic changes mediated by dopamine receptors: Role of the cerebral microvasculature in dopamine-mediated neurovascular coupling

The coupling between neurotransmitter-induced changes in neuronal activity and the resultant hemodynamic response is central to the interpretation of neuroimaging techniques. In the present study, MRI experiments showed that dopamine transporter blockers such as cocaine and dopamine releasers such as amphetamine and D1 receptor agonists induced large positive increases in relative cerebral blood volume (rCBV) that were not sensitive to nitric oxide synthase inhibition. However, D1/D5 receptor antagonism with SCH-23390 prevented or blocked the hemodynamic response without any concomitant effect on dopamine release. Dopamine D2/D3 receptor agonists, in contrast, induced negative changes in rCBV in brain regions corresponding largely to those endowed with these receptors. D1 and D5 receptor mRNAs were expressed in microvessels of responsive brain areas, while D2 and D3 receptors were not consistently associated with the microvascular bed. D3 receptors had an astroglial localization. Together, these experiments show that direct effects of dopamine upon the vasculature cannot be ignored in measuring the hemodynamic coupling associated with dopaminergic drugs. These results further suggest that this coupling is partially mediated through D1/D5 receptors on the microvasculature leading to increased rCBV and through astroglial D3 receptors leading to decreased rCBV. These data provide additional support for the role of local post-synaptic events in neurovascular coupling and emphasize that the interpretation of fMRI signals exclusively in terms of neuronal activity may be incomplete.

Degradation kinetics and mechanism of RDX and HMX in TiO2 photocatalysis

This study was undertaken to examine the photocatalytic degradation of explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) with a circular photocatalytic reactor, using a UV lamp as a light source and TiO2 as a photocatalyst. The effects of various parameters, such as the RDX or HMX concentration, the amount of TiO, and the initial pH, on the photocatalytic degradation rates of explosives were examined. In the presence of both UV light and TiO2 RDX and HMX were more effectively degraded than with either UV or TiO2 alone. The degradation rates were found to obey pseudo-first-order kinetics represented by the Langmuir-Hinshelwood model. Increases in the RDX and HMX degradation rates were obtained with decreasing initial concentrations of the explosives. The RDX and HMX degradation rates were higher at pH 7 than at either pH 3 or pH 11. A dose of approximately 0.7 g l(-1) of TiO2 degraded HMX more rapidly than did higher or lower TiO2 doses. RDX (20 mg l(-1)) photocatalysis resulted in an approximately 20% decrease in TOC, and HMX (5 mg l(-1)) photocatalysis resulted in a 60%, decrease in TOC within 150 minutes. A trace amount of formate was produced as an intermediate that was further mineralized by RDX or HMX photocatalysis. The nitrogen byproducts from the photocatalysis of RDX and HMX were mainly NO3- with NO2-, and NH4+. The total nitrogen recovery was about 60% from RDX (20 mg l(-1)), and 70% from HMX (5 mg l(-1)), respectively. Finally, a mechanism for RDX/HMX photocatalysis was proposed, along with supporting qualitative and quantitative evidence.

High resolution spatial mapping of nicotine action using pharmacologic magnetic resonance imaging

Nicotine is one of the most addictive substances known. To better understand the mechanisms of action, we mapped the regional brain response to nicotine administration using pharmacologic magnetic resonance imaging (phMRI) in rats. We measured the regional response of relative cerebral blood volume (rCBV) in rats to a challenge of 0.07 mg/kg (0.43 micromol/kg) of nicotine. The areas of the brain with significant and reproducible changes in the rCBV response were (in descending order of magnitude) infralimbic cortex, hippocampus (subiculum), agranular insular/pyriform cortex, visual cortex, interpeduncular area, nucleus accumbens, cingulate cortex, thalamus, and septum. This pattern of response is consistent with stimulation of both cholinergic and dopaminergic neuronal pathways and is consistent with the known behavioral properties of nicotine. The peak CBV response to nicotine occurred between 9 and 13 min depending upon brain region, and the average full width half-maximum of the rCBV response was 27 min. The high spatial and temporal resolution of the phMRI technique lends itself well to further, more detailed, studies of nicotine dynamics.