Molecular phylogeny and morphology of Sporodiniella sinensis sp. nov. (Syzygitaceae, Mucorales), an invertebrate-associated species from Yunnan, China.

During investigations of invertebrate-associated fungi in Yunnan Province of China, a new species, Sporodiniella sinensis sp. nov., was collected. Morphologically, S. sinensis is similar to Sporodiniella umbellata; however, it is distinguished from S. umbellata by its greater number of sporangiophore branches, longer sporangiophores, larger sporangiospores, and columellae. The novel species exhibits similarities of 91.62 % for internal transcribed spacer (ITS), 98.66-99.10 % for ribosomal small subunit (nrSSU), and 96.36-98.22 % for ribosomal large subunit (nrLSU) sequences, respectively, compared to S. umbellata. Furthermore, phylogenetic analyses based on combined sequences of ITS, nrLSU and nrSSU show that it forms a separate clade in Sporodiniella, and clusters closely with S. umbellata with high statistical support. The phylogenetic and morphological evidence support S. sinensis as a distinct species. Here, it is formally described and illustrated, and compared with other relatives.

Genetic and genomic signatures in ethanol withdrawal seizure-prone and seizure-resistant mice implicate genes involved in epilepsy and neuronal excitability.

Alcohol withdrawal is a clinically important consequence and potential driver of Alcohol Use Disorder. However, susceptibility to withdrawal symptoms, ranging from craving and anxiety to seizures and delirium, varies greatly. Selectively bred Withdrawal Seizure-Prone (WSP) and Seizure-Resistant (WSR) mice are an animal model of differential susceptibility to withdrawal and phenotypes with which withdrawal severity correlates. To identify innate drivers of alcohol withdrawal severity, we performed a multi-omic study of the WSP and WSR lines and F2 mice derived from them, using genomic, genetic, and transcriptomic analyses. Genes implicated in seizures and epilepsy were over-represented among those that segregated between WSP and WSR mice and that displayed differential expression in F2 mice high and low in withdrawal. Quantitative trait locus (QTL) analysis of ethanol withdrawal convulsions identified several genome-wide significant loci and pointed to genes that modulate potassium channel function and neural excitability. Perturbations of expression of genes involved in synaptic transmission, including GABAergic and glutamatergic genes, were prominent in prefrontal cortex transcriptome. Expression QTL (eQTL) analysis fine mapped genes within the peak ethanol withdrawal QTL regions. Genetic association analysis in human subjects provided converging evidence for the involvement of those genes in severity of alcohol withdrawal and dependence. Our results reveal a polygenic network and neural signaling pathways contributing to ethanol withdrawal seizures and related phenotypes that overlap with genes modulating epilepsy and neuronal excitability.

Elevated transferrin saturation in individuals with alcohol use disorder: Association with HFE polymorphism and alcohol withdrawal severity.

Iron loading has been consistently reported in those with alcohol use disorder (AUD), but its effect on the clinical course of the disease is not yet fully understood. Here, we conducted a cohort study to examine whether peripheral iron measures, genetic variation in HFE rs1799945 and their interaction differed between 594 inpatient participants with alcohol use disorder (AUD) undergoing detoxification and 472 healthy controls (HC). We also assessed whether HFE rs1799945 was associated with elevated peripheral iron and can serve as a predictor of withdrawal severity. AUD patients showed significantly higher serum transferrin saturation than HC. Within the AUD group, transferrin saturation significantly predicted withdrawal symptoms (CIWA-Ar) and cumulative dose of benzodiazepine treatment during the first week of detoxification, which is an indicator of withdrawal severity. HFE rs1799945 minor allele carriers showed elevated transferrin saturation compared to non-carriers, both in AUD and healthy controls. Exploratory analyses indicated that, within the AUD cohort, HFE rs1799945 predicted CIWA withdrawal scores, and this relationship was significantly mediated by transferrin saturation. We provide evidence that serum transferrin saturation predicts alcohol withdrawal severity in AUD. Moreover, our findings replicated previous studies on elevated serum transferrin saturation in AUD and an involvement of HFE rs1799945 in serum transferrin saturation levels in both AUD and healthy controls. Future studies may use transferrin saturation measures as predictors for treatment or potentially treat iron overload to ameliorate withdrawal symptoms.

Exploratory locomotion, a predictor of addiction vulnerability, is oligogenic in rats selected for this phenotype.

Artificially selected model organisms can reveal hidden features of the genetic architecture of the complex disorders that they model. Addictions are disease phenotypes caused by different intermediate phenotypes and pathways and thereby are potentially highly polygenic. High responder (bHR) and low responder (bLR) rat lines have been selectively bred (b) for exploratory locomotion (EL), a behavioral phenotype correlated with novelty-seeking, impulsive response to reward, and vulnerability to addiction, and is inversely correlated with spontaneous anxiety and depression-like behaviors. The rapid response to selection indicates loci of large effect for EL. Using exome sequencing of HR and LR rats, we identified alleles in gene-coding regions that segregate between the two lines. Quantitative trait locus (QTL) analysis in F2 rats derived from a bHR × bLR intercross confirmed that these regions harbored genes affecting EL. The combined effects of the seven genome-wide significant QTLs accounted for approximately one-third of the total variance in EL, and two-thirds of the variance attributable to genetic factors, consistent with an oligogenic architecture of EL estimated both from the phenotypic distribution of F2 animals and rapid response to selection. Genetic association in humans linked APBA2, the ortholog of the gene at the center of the strongest QTL, with substance use disorders and related behavioral phenotypes. Our finding is also convergent with molecular and animal behavioral studies implicating Apba2 in locomotion. These results provide multilevel evidence for genes/loci influencing EL. They shed light on the genetic architecture of oligogenicity in animals artificially selected for a phenotype modeling a more complex disorder in humans.

Association of Superoxide Dismutase 2 (SOD2) Genotype with Gray Matter Volume Shrinkage in Chronic Alcohol Users: Replication and Further Evaluation of an Addiction Gene Panel.

BACKGROUND: Reduction in brain volume, especially gray matter volume, has been shown to be one of the many deleterious effects of prolonged alcohol consumption. High variance in the degree of gray matter tissue shrinkage among alcohol-dependent individuals and a previous neuroimaging genetics report suggest the involvement of environmental and/or genetic factors, such as superoxide dismutase 2 (SOD2). Identification of such underlying factors will help in the clinical management of alcohol dependence. METHODS: We analyzed quantitative magnetic resonance imaging and genotype data from 103 alcohol users, including both light drinkers and treatment-seeking alcohol-dependent individuals. Genotyping was performed using a custom gene array that included genes selected from 8 pathways relevant to chronic alcohol-related brain volume loss. RESULTS: We replicated a significant association of a functional SOD2 single nucleotide polymorphism with normalized gray matter volume, which had been reported previously in an independent smaller sample of alcohol-dependent individuals. The SOD2-related genetic protection was observed only at the cohort's lower drinking range. Additional associations between normalized gray matter volume and other candidate genes such as alcohol dehydrogenase gene cluster (ADH), GCLC, NOS3, and SYT1 were observed across the entire sample but did not survive corrections for multiple comparisons. CONCLUSION: Converging independent evidence for a SOD2 gene association with gray matter volume shrinkage in chronic alcohol users suggests that SOD2 genetic variants predict differential brain volume loss mediated by free radicals. This study also provides the first catalog of genetic variations relevant to gray matter loss in chronic alcohol users. The identified gene-brain structure relationships are functionally pertinent and merit replication.

Association of the OPRM1 Variant rs1799971 (A118G) with Non-Specific Liability to Substance Dependence in a Collaborative de novo Meta-Analysis of European-Ancestry Cohorts.

The mu1 opioid receptor gene, OPRM1, has long been a high-priority candidate for human genetic studies of addiction. Because of its potential functional significance, the non-synonymous variant rs1799971 (A118G, Asn40Asp) in OPRM1 has been extensively studied, yet its role in addiction has remained unclear, with conflicting association findings. To resolve the question of what effect, if any, rs1799971 has on substance dependence risk, we conducted collaborative meta-analyses of 25 datasets with over 28,000 European-ancestry subjects. We investigated non-specific risk for "general" substance dependence, comparing cases dependent on any substance to controls who were non-dependent on all assessed substances. We also examined five specific substance dependence diagnoses: DSM-IV alcohol, opioid, cannabis, and cocaine dependence, and nicotine dependence defined by the proxy of heavy/light smoking (cigarettes-per-day >20 vs. ≤ 10). The G allele showed a modest protective effect on general substance dependence (OR = 0.90, 95% C.I. [0.83-0.97], p value = 0.0095, N = 16,908). We observed similar effects for each individual substance, although these were not statistically significant, likely because of reduced sample sizes. We conclude that rs1799971 contributes to mechanisms of addiction liability that are shared across different addictive substances. This project highlights the benefits of examining addictive behaviors collectively and the power of collaborative data sharing and meta-analyses.

GABBR1 and SLC6A1, Two Genes Involved in Modulation of GABA Synaptic Transmission, Influence Risk for Alcoholism: Results from Three Ethnically Diverse Populations.

BACKGROUND: Animal and human studies indicate that GABBR1, encoding the GABAB1 receptor subunit, and SLC6A1, encoding the neuronal gamma-aminobutyric acid (GABA) transporter GAT1, play a role in addiction by modulating synaptic GABA. Therefore, variants in these genes might predict risk/resilience for alcoholism. METHODS: This study included 3 populations that differed by ethnicity and alcoholism phenotype: African American (AA) men: 401 treatment-seeking inpatients with single/comorbid diagnoses of alcohol and drug dependence, 193 controls; Finnish Caucasian men: 159 incarcerated alcoholics, half with comorbid antisocial personality disorder, 181 controls; and a community sample of Plains Indian (PI) men and women: 239 alcoholics, 178 controls. Seven GABBR1 tag single nucleotide polymorphisms were genotyped in the AA and Finnish samples; rs29220 was genotyped in the PI for replication. Also, a uniquely African, functional SLC6A1 insertion promoter polymorphism (IND) was genotyped in the AAs. RESULTS: We found a significant and congruent association between GABBR1 rs29220 and alcoholism in all 3 populations. The major genotype (heterozygotes in AAs, Finns) and the major allele in PIs were significantly more common in alcoholics. Moreover, SLC6A1 IND was more abundant in controls, that is, the major genotype predicted alcoholism. An analysis of combined GABBR1 rs29220 and SLC6A1 IND genotypes showed that rs29220 heterozygotes, irrespective of their IND status, had an increased risk for alcoholism, whereas carriers of the IND allele and either rs29220 homozygote were more resilient. CONCLUSIONS: Our results show that with both GABBR1 and SLC6A1, the minor genotypes/alleles were protective against risk for alcoholism. Finally, GABBR1 rs29220 might predict treatment response/adverse effects for baclofen, a GABAB receptor agonist.

Loss of metabotropic glutamate receptor 2 escalates alcohol consumption.

Identification of genes influencing complex traits is hampered by genetic heterogeneity, the modest effect size of many alleles, and the likely involvement of rare and uncommon alleles. Etiologic complexity can be simplified in model organisms. By genomic sequencing, linkage analysis, and functional validation, we identified that genetic variation of Grm2, which encodes metabotropic glutamate receptor 2 (mGluR2), alters alcohol preference in animal models. Selectively bred alcohol-preferring (P) rats are homozygous for a Grm2 stop codon (Grm2 *407) that leads to largely uncompensated loss of mGluR2. mGluR2 receptor expression was absent, synaptic glutamate transmission was impaired, and expression of genes involved in synaptic function was altered. Grm2 *407 was linked to increased alcohol consumption and preference in F2 rats generated by intercrossing inbred P and nonpreferring rats. Pharmacologic blockade of mGluR2 escalated alcohol self-administration in Wistar rats, the parental strain of P and nonpreferring rats. The causal role of mGluR2 in altered alcohol preference was further supported by elevated alcohol consumption in Grm2 (-/-) mice. Together, these data point to mGluR2 as an origin of alcohol preference and a potential therapeutic target.

Genetic variation in human NPY expression affects stress response and emotion.

Understanding inter-individual differences in stress response requires the explanation of genetic influences at multiple phenotypic levels, including complex behaviours and the metabolic responses of brain regions to emotional stimuli. Neuropeptide Y (NPY) is anxiolytic and its release is induced by stress. NPY is abundantly expressed in regions of the limbic system that are implicated in arousal and in the assignment of emotional valences to stimuli and memories. Here we show that haplotype-driven NPY expression predicts brain responses to emotional and stress challenges and also inversely correlates with trait anxiety. NPY haplotypes predicted levels of NPY messenger RNA in post-mortem brain and lymphoblasts, and levels of plasma NPY. Lower haplotype-driven NPY expression predicted higher emotion-induced activation of the amygdala, as well as diminished resiliency as assessed by pain/stress-induced activations of endogenous opioid neurotransmission in various brain regions. A single nucleotide polymorphism (SNP rs16147) located in the promoter region alters NPY expression in vitro and seems to account for more than half of the variation in expression in vivo. These convergent findings are consistent with the function of NPY as an anxiolytic peptide and help to explain inter-individual variation in resiliency to stress, a risk factor for many diseases.

Molecular phylogeny and morphology reveal two new entomopathogenic species of Ophiocordyceps (Ophiocordycipitaceae, Hypocreales) parasitic on termites from China.

Two new termite-pathogenic species, Ophiocordycepsglobiperitheciata and O.longistipes, are described from Yunnan Province, China. Six-locus (ITS, nrSSU, nrLSU, tef-1α, rpb1 and rpb2) phylogenetic analyses in combination with morphological observations were employed to characterize these two species. Phylogenetically, O.globiperitheciata is most closely related to Hirsutellacryptosclerotium and O.communis, whereas O.longistipes shares a sister relationship with O.fusiformis. However, O.globiperitheciata differs from H.cryptosclerotium by parasitizing Blattodea and producing clavate, unbifurcated stromata. Ophiocordycepsglobiperitheciata is distinguished from O.communis by multiple stromata, shorter asci and ascospores. Ophiocordycepslongistipes differs from O.fusiformis in producing larger stromata, perithecia, asci and ascospores, as well as smaller citriform or oval conidia. Morphological descriptions of the two new species and a dichotomous key to the 19 termite-pathogenic Ophiocordyceps species are presented.

A patient-based iPSC-derived hepatocyte model of alcohol-associated cirrhosis reveals bioenergetic insights into disease pathogenesis.

Only ~20% of heavy drinkers develop alcohol cirrhosis (AC). While differences in metabolism, inflammation, signaling, microbiome signatures and genetic variations have been tied to the pathogenesis of AC, the key underlying mechanisms for this interindividual variability, remain to be fully elucidated. Induced pluripotent stem cell-derived hepatocytes (iHLCs) from patients with AC and healthy controls differ transcriptomically, bioenergetically and histologically. They include a greater number of lipid droplets (LDs) and LD-associated mitochondria compared to control cells. These pre-pathologic indicators are effectively reversed by Aramchol, an inhibitor of stearoyl-CoA desaturase. Bioenergetically, AC iHLCs have lower spare capacity, slower ATP production and their mitochondrial fuel flexibility towards fatty acids and glutamate is weakened. MARC1 and PNPLA3, genes implicated by GWAS in alcohol cirrhosis, show to correlate with lipid droplet-associated and mitochondria-mediated oxidative damage in AC iHLCs. Knockdown of PNPLA3 expression exacerbates mitochondrial deficits and leads to lipid droplets alterations. These findings suggest that differences in mitochondrial bioenergetics and lipid droplet formation are intrinsic to AC hepatocytes and can play a role in its pathogenesis.

Leptin regulates dopamine responses to sustained stress in humans.

Neural systems that identify and respond to salient stimuli are critical for survival in a complex and changing environment. In addition, interindividual differences, including genetic variation and hormonal and metabolic status likely influence the behavioral strategies and neuronal responses to environmental challenges. Here, we examined the relationship between leptin allelic variation and plasma leptin levels with DAD2/3R availability in vivo as measured with [(11)C]raclopride PET at baseline and during a standardized pain stress challenge. Allelic variation in the leptin gene was associated with varying levels of dopamine release in response to the pain stressor, but not with baseline D2/3 receptor availability. Circulating leptin was also positively associated with stress-induced dopamine release. These results show that leptin serves as a regulator of neuronal function in humans and provides an etiological mechanism for differences in dopamine neurotransmission in response to salient stimuli as related to metabolic function. The capacity for leptin to influence stress-induced dopaminergic function is of importance for pathological states where dopamine is thought to play an integral role, such as mood, substance-use disorders, eating disorders, and obesity.

Striatal dopamine release and genetic variation of the serotonin 2C receptor in humans.

Mesoaccumbal and nigrostriatal projections are sensitive to stress, and heightened stress sensitivity is thought to confer risk for neuropsychiatric disorders. Serotonin 2C (5-HT(2C)) receptors mediate the inhibitory effects of serotonin on dopaminergic circuitry in experimental animals, and preclinical findings have implicated 5-HT(2C) receptors in motivated behaviors and psychotropic drug mechanisms. In humans, a common missense single-nucleotide change (rs6318, Cys23Ser) in the 5-HT(2C) receptor gene (HTR2C) has been associated with altered activity in vitro and with clinical mood disorders. We hypothesized that dopaminergic circuitry would be more sensitive to stress in humans carrying the Ser23 variant. To test this hypothesis, we studied 54 healthy humans using positron emission tomography and the displaceable D(2)/D(3) receptor radiotracer [(11)C]raclopride. Binding potential (BP(ND)) was quantified before and after a standardized stress challenge consisting of 20 min of moderate deep muscular pain, and reduction in BP(ND) served as an index of dopamine release. The Cys23Ser variant was genotyped on a custom array, and ancestry informative markers were used to control for population stratification. We found greater dopamine release in the nucleus accumbens, caudate nucleus, and putamen among Ser23 carriers, after controlling for sex, age, and ancestry. Genotype accounted for 12% of the variance in dopamine release in the nucleus accumbens. There was no association of Cys23Ser with baseline BP(ND). These findings indicate that a putatively functional HTR2C variant (Ser23) is associated with greater striatal dopamine release during pain in healthy humans. Mesoaccumbal stress sensitivity may mediate the effects of HTR2C variation on risk of neuropsychiatric disorders.

Prefrontal white matter impairment in substance users depends upon the catechol-o-methyl transferase (COMT) val158met polymorphism.

Individuals addicted to most chemical substances present with hypoactive dopaminergic systems as well as altered prefrontal white matter structure. Prefrontal dopaminergic tone is under genetic control and is influenced by and modulates descending cortico-striatal glutamatergic pathways that in turn, regulate striatal dopamine release. The catechol-O-methyltransferase (COMT) gene contains an evolutionarily recent and common functional variant at codon 108/158 (rs4680) that plays an important role in modulating prefrontal dopaminergic tone. To determine if the COMT val158met genotype influences white matter integrity (i.e., fractional anisotropy (FA)) in substance users, 126 healthy controls and 146 substance users underwent genotyping and magnetic resonance imaging. A general linear model with two between-subjects factors (COMT genotype and addiction status) was performed using whole brain diffusion tensor imaging (DTI) to assess FA. A significant Genotype × Drug Use status interaction was found in the left prefrontal cortex. Post-hoc analysis showed reduced prefrontal FA only in Met/Met homozygotes who were also drug users. These data suggest that Met/Met homozygous individuals, in the context of addiction, have increased susceptibility to white matter structural alterations, which might contribute to previously identified structural and functional prefrontal cortical deficits in addiction.

DRD2/ANKK1 Taq1A polymorphism (rs1800497) has opposing effects on D2/3 receptor binding in healthy controls and patients with major depressive disorder.

The A1 allele of the DRD2/ANKK1 Taq1A polymorphism (rs1800497) is associated with reduced striatal D(2/3) receptor binding in healthy individuals (Con) as well as depression and addiction. However, the effect of rs1800497 on D(2/3) receptor binding in depressed patients as well as the SNP's effect on D(2/3) binding during reward-associated dopamine release is unknown. Twelve unmedicated patients with major depressive disorder (MDD) and 24 Con completed PET scans with [(11)C]raclopride, once without receiving monetary rewards (baseline) and once while winning money. In Con, the A1 allele was associated with reduced baseline binding potential (BP(ND)) in the middle caudate and ventral striatum. However, in MDD patients the A1 allele was associated with increased baseline BP(ND) in these regions. There were no significant associations between rs1800497 and change in BP(ND) during reward-associated dopamine release. Conceivably, the A1 allele predisposes to depression and addiction via its effect on the post-synaptic D(2) receptor.

Estimating ancestral proportions in a multi-ethnic US sample: implications for studies of admixed populations.

This study was designed to determine the ancestral composition of a multi-ethnic sample collected for studies of drug addictions in New York City and Las Vegas, and to examine the reliability of self-identified ethnicity and three-generation family history data. Ancestry biographical scores for seven clusters corresponding to world major geographical regions were obtained using STRUCTURE, based on genotypes of 168 ancestry informative markers (AIMs), for a sample of 1,291 African Americans (AA), European Americans (EA), and Hispanic Americans (HA) along with data from 1,051 HGDP-CEPH 'diversity panel' as a reference. Self-identified ethnicity and family history data, obtained in an interview, were accurate in identifying the individual major ancestry in the AA and the EA samples (approximately 99% and 95%, respectively) but were not useful for the HA sample and could not predict the extent of admixture in any group. The mean proportions of the combined clusters corresponding to European and Middle Eastern populations in the AA sample, revealed by AIMs analysis, were 0.13. The HA subjects, predominantly Puerto Ricans, showed a highly variable hybrid contribution pattern of clusters corresponding to Europe (0.27), Middle East (0.27), Africa (0.20), and Central Asia (0.14). The effect of admixture on allele frequencies is demonstrated for two single-nucleotide polymorphisms (118A > G, 17 C > T) of the mu opioid receptor gene (OPRM1). This study reiterates the importance of AIMs in defining ancestry, especially in admixed populations.

Genome-wide association identifies candidate genes that influence the human electroencephalogram.

Complex psychiatric disorders are resistant to whole-genome analysis due to genetic and etiological heterogeneity. Variation in resting electroencephalogram (EEG) is associated with common, complex psychiatric diseases including alcoholism, schizophrenia, and anxiety disorders, although not diagnostic for any of them. EEG traits for an individual are stable, variable between individuals, and moderately to highly heritable. Such intermediate phenotypes appear to be closer to underlying molecular processes than are clinical symptoms, and represent an alternative approach for the identification of genetic variation that underlies complex psychiatric disorders. We performed a whole-genome association study on alpha (alpha), beta (beta), and theta (theta) EEG power in a Native American cohort of 322 individuals to take advantage of the genetic and environmental homogeneity of this population isolate. We identified three genes (SGIP1, ST6GALNAC3, and UGDH) with nominal association to variability of theta or alpha power. SGIP1 was estimated to account for 8.8% of variance in power, and this association was replicated in US Caucasians, where it accounted for 3.5% of the variance. Bayesian analysis of prior probability of association based upon earlier linkage to chromosome 1 and enrichment for vesicle-related transport proteins indicates that the association of SGIP1 with theta power is genuine. We also found association of SGIP1 with alcoholism, an effect that may be mediated via the same brain mechanisms accessed by theta EEG, and which also provides validation of the use of EEG as an endophenotype for alcoholism.

[Effects of Nitrogen Speciation Transformation on Microbial Community Succession in Input Rivers of Miyun Reservoir].

The Miyun Reservoir is the major source of surface drinking water in Beijing. However, the total nitrogen (TN) concentrations in the Miyun Reservoir and inflowing rivers have recently been increasing. In this study, the Mangniu River, a typical inflow river in the upper reaches of the Miyun Reservoir, was selected as the study area to investigate the spatial distribution and transformation of various nitrogen forms from the perspective of microbial community composition and predicting function, aimimg at providing a scientific reference for nitrogen pollution control of the Miyun Reservoir. The results indicated that except for TN, all the other physical and chemical water quality indicators in the upper reaches of the Miyun Reservoir met the Class II criteria of the environmental quality standards for surface water in China (GB 3838-2002). Additionally, NO3--N was the primary constituent of TN, ranging from 77.7% to 92.9%. Banchengzi Reservoir has a certain self-purification ability because its high C/N ratio promotes denitrification. Significant differences in microbial community structure were observed between the water and sediments of Mangniu River along with spatial distribution. High NO3--N concentration was the major environmental factor affecting the succession of microbial community structure. Many nitrification and denitrification microorganisms existed in Mengniu River, and the relative abundance of denitrification bacteria (DNB) was higher than that of nitrification bacteria, and that in the sediments was slightly higher than that in the water. Nitrosopumilus and Pseudomonas were the dominant nitrification and denitrification bacteria in Mengniuhe River, respectively. The results of phylogenetic investigation of communities by the reconstruction of unobserved states (PICRUSt2) showed that NO3--N reduction module was the major nitrogen metabolism module, which primarily occurred in water. The abundance of the functional genes for nitrification (i.e., narGH) was the highest in water, and the major functional gene involved in NO3--N reduction was nirBD of DNRA, which was primarily present in the sediments; however, the main functional gene involved in denitrification was nirK.

Low Dopamine D2 Receptor Expression Drives Gene Networks Related to GABA, cAMP, Growth and Neuroinflammation in Striatal Indirect Pathway Neurons.

Background: A salient effect of addictive drugs is to hijack the dopamine reward system, an evolutionarily conserved driver of goal-directed behavior and learning. Reduced dopamine type 2 receptor availability in the striatum is an important pathophysiological mechanism for addiction that is both consequential and causal for other molecular, cellular, and neuronal network differences etiologic for this disorder. Here, we sought to identify gene expression changes attributable to innate low expression of the Drd2 gene in the striatum and specific to striatal indirect medium spiny neurons (iMSNs). Methods: Cre-conditional, translating ribosome affinity purification (TRAP) was used to purify and analyze the translatome (ribosome-bound messenger RNA) of iMSNs from mice with low/heterozygous or wild-type Drd2 expression in iMSNs. Complementary electrophysiological recordings and gene expression analysis of postmortem brain tissue from human cocaine users were performed. Results: Innate low expression of Drd2 in iMSNs led to differential expression of genes involved in GABA (gamma-aminobutyric acid) and cAMP (cyclic adenosine monophosphate) signaling, neural growth, lipid metabolism, neural excitability, and inflammation. Creb1 was identified as a likely upstream regulator, among others. In human brain, expression of FXYD2, a modulatory subunit of the Na/K pump, was negatively correlated with DRD2 messenger RNA expression. In iMSN-TRAP-Drd2HET mice, increased Cartpt and reduced S100a10 (p11) expression recapitulated previous observations in cocaine paradigms. Electrophysiology experiments supported a higher GABA tone in iMSN-Drd2HET mice. Conclusions: This study provides strong molecular evidence that, in addiction, inhibition by the indirect pathway is constitutively enhanced through neural growth and increased GABA signaling.

Haplotype-based study of the association of alcohol-metabolizing genes with alcohol dependence in four independent populations.

BACKGROUND: Ethanol is metabolized by 2 rate-limiting reactions: alcohol dehydrogenases (ADH) convert ethanol to acetaldehyde that is subsequently metabolized to acetate by aldehyde dehydrogenases (ALDH). Approximately 50% of East Asians have genetic variants that significantly impair this pathway and influence alcohol dependence (AD) vulnerability. We investigated whether variation in alcohol metabolism genes might alter the AD risk in four non-East Asian populations by performing systematic haplotype association analyses to maximize the chances of capturing functional variation. METHODS: Haplotype-tagging SNPs were genotyped using the Illumina GoldenGate platform. Genotypes were available for 40 SNPs across the ADH genes cluster and 24 SNPs across the two ALDH genes in four diverse samples that included cases (lifetime AD) and controls (no Axis 1 disorders). The case control sample sizes were the following: Finnish Caucasians: 232, 194; African Americans: 267, 422; Plains American Indians: 226, 110; and Southwestern American (SW) Indians: 317, 72. RESULTS: In all four populations, as well as HapMap populations, 5 haplotype blocks were identified across the ADH gene cluster: (i) ADH5-ADH4; (ii) ADH6-ADH1A-ADH1B; (iii) ADH1C; (iv) intergenic; (v) ADH7. The ALDH1A1 gene was defined by 4 blocks and ALDH2 by 1 block. No haplotype or SNP association results were significant after correction for multiple comparisons; however, several results, particularly for ALDH1A1 and ADH4, replicated earlier findings. There was an ALDH1A1 block 1 and 2 (extending from intron 5 to the 3' UTR) yin yang haplotype (haplotypes that have opposite allelic configuration) association with AD in the Finns driven by SNPs rs3764435 and rs2303317, respectively, and an ALDH1A1 block 3 (including the promoter region) yin yang haplotype association in SW Indians driven by 5 SNPs, all in allelic identity. The ADH4 SNP rs3762894 was associated with AD in Plains Indians. CONCLUSIONS: The systematic evaluation of alcohol-metabolizing genes in four non-East Asian populations has shown only modest associations with AD, largely for ALDH1A1 and ADH4. A concentration of signals for AD with ALDH1A1 yin yang haplotypes in several populations warrants further study.