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Calcium-dependent nuclear export of histone deacetylase 1 (HDAC1) was shown previously to precede axonal damage in culture, but the in vivo relevance of these findings and the potential posttranslational modifications of HDAC1 remained elusive. Using acute hippocampal slices from mice of either sex with genetic conditional ablation of Hdac1 in CA1 hippocampal neurons (i.e., Camk2a-cre;Hdac1fl/fl), we show significantly diminished axonal damage in response to neurotoxic stimuli. The protective effect of Hdac1 ablation was detected also in CA3 neurons in Grik4-cre;Hdac1fl/f mice, which were more resistant to the excitotoxic damage induced by intraventricular injection of kainic acid. The amino acid residues modulating HDAC1 subcellular localization were identified by site-directed mutagenesis, which identified serine residues 421 and 423 as critical for its nuclear localization. The physiological phosphorylation of HDAC1 was decreased by neurotoxic stimuli, which stimulated the phosphatase enzymatic activity of calcineurin. Treatment of neurons with the calcineurin inhibitors FK506 or cyclosporin A resulted in nuclear accumulation of phospho-HDAC1 and was neuroprotective. Together, our data identify HDAC1 and the phosphorylation of specific serine residues in the molecule as potential targets for neuroprotection. [ABSTRACT FROM AUTHOR]

Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) can cause Parkinson's disease (PD), and the most common disease-associated mutation, G2019S, increases kinase activity. Because LRRK2 expression levels rise during synaptogenesis and are highest in dorsal striatal spiny projection neurons (SPNs), we tested the hypothesis that the LRRK2-G2019S mutation would alter development of excitatory synaptic networks in dorsal striatum. To circumvent experimental confounds associated with LRRK2 overexpression, we used mice expressing LRRK2-G2019S or D2017A (kinase-dead) knockin mutations. In whole-cell recordings, G2019S SPNs exhibited a fourfold increase in sEPSC frequency compared with wild-type SPNs in postnatal day 21 mice. Such heightened neural activity was increased similarly in direct- and indirect-pathway SPNs, and action potential-dependent activity was particularly elevated. Excitatory synaptic activity in D2017A SPNs was similar to wild type, indicating a selective effect of G2019S. Acute exposure to LRRK2 kinase inhibitors normalized activity, supporting that excessive neural activity in G2019S SPNs is mediated directly and is kinase dependent. Although dendritic arborization and densities of excitatory presynaptic terminals and postsynaptic dendritic spines in G2019S SPNs were similar to wild type, G2019S SPNs displayed larger spines that were matched functionally by a shift toward larger postsynaptic response amplitudes. Acutely isolating striatum from overlying neocortex normalized sEPSC frequency in G2019S mutants, supporting that abnormal corticostriatal activity is involved. These findings indicate that the G2019S mutation imparts a gain-of-abnormal function to SPN activity and morphology during a stage of development when activity can permanently modify circuit structure and function. [ABSTRACT FROM AUTHOR]

The dorsal subcoeruleus nucleus (SubCD) is involved in generating two signs of rapid eye movement (REM) sleep: muscle atonia and ponto-geniculo-occipital (PGO) waves. We tested the hypothesis that single cell and/or population responses of SubCD neurons are capable of generating gamma frequency activity in response to intracellular stimulation or receptor agonist activation. Whole cell patch clamp recordings (immersion chamber) and population responses (interface chamber) were conducted on 9- to 20-day-old rat brain stem slices. All SubCD neurons (n = 103) fired at gamma frequency when subjected to depolarizing steps. Two statistically distinct populations of neurons were observed, which were distinguished by their high (>80 Hz, n = 24) versus low (35-80 Hz, n = 16) initial firing frequencies. Both cell types exhibited subthreshold oscillations in the gamma range (n = 43), which may underlie the gamma band firing properties of these neurons. The subthreshold oscillations were blocked by the sodium channel blockers tetrodotoxin (TTX, n = 21) extracellularly and N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (QX-314) intracellularly (n = 5), indicating they were sodium channel dependent. Gamma frequency subthreshold oscillations were observed in response to the nonspecific cholinergic receptor agonist carbachol (CAR, n = 11, d = 1.08) and the glutamate receptor agonists N-methyl-d-aspartic acid (NMDA, n = 12, d = 1.09) and kainic acid (KA, n = 13, d = 0.96), indicating that cholinergic and glutamatergic inputs may be involved in the activation of these subthreshold currents. Gamma band activity also was observed in population responses following application of CAR (n = 4, P < 0.05), NMDA (n = 4, P < 0.05) and KA (n = 4, P < 0.05). Voltage-sensitive, sodium channel-dependent gamma band activity appears to be a part of the intrinsic membrane properties of SubCD neurons.

Bacteroidales are fecal anaerobic bacteria that are common in the digestive systems and feces of warm-blooded animals. Some strains of Bacteroidales have been reported to be host-specific. In this study, Bacteroidales strains from chicken feces were examined for their potential use as indicators of chicken fecal contamination. Bacteroidales 16S rRNA gene sequences from chicken feces were amplified, cloned and sequenced. Phylogenetic analysis was performed using these sequences and published Bacteroidales 16S rRNA gene sequences from human and bovine feces. Primers were designed based on putative chicken feces-specific 16S rRNA gene sequences and the primer pairs were tested for specificity in PCR assays. One set of primers, chBact F1 and chBact R16, specifically amplified DNA from chicken feces in a PCR assay, but did not amplify wild turkey, cat, bovine, or deer fecal DNAs. In addition, DNA from feces contaminated straw-based chicken litter produced a product in the PCR assay. However, DNA from feces contaminated wood shavings-based chicken litter was not amplified. The PCR assay described here may prove a useful tool for the detection of chicken feces and for source tracking in watersheds with fecal contamination.