Antidepressive and anxiolytic effects of ostruthin, a TREK-1 channel activator

We screened a library of botanical compounds purified from plants of Vietnam for modulators of the activity of a two-pore domain K+ channel, TREK-1, and we identified a hydroxycoumarin-related compound, ostruthin, as an activator of this channel. Ostruthin increased whole-cell TREK-1 channel currents in 293T cells at a low concentration (EC50 = 5.3 μM), and also activity of the TREK-2 channel (EC50 = 3.7 mM). In contrast, ostruthin inhibited other K+ channels, e.g. human ether-à-go-go-related gene (HERG1), inward-rectifier (Kir2.1), voltage-gated (Kv1.4), and two-pore domain (TASK-1) at higher concentrations, without affecting voltage-gated potassium channel (KCNQ1 and 3). We tested the effect of this compound on mouse anxiety- and depression-like behaviors and found anxiolytic activity in the open-field, elevated plus maze, and light/dark box tests. Of note, ostruthin also showed antidepressive effects in the forced swim and tail suspension tests, although previous studies reported that inhibition of TREK-1 channels resulted in an antidepressive effect. The anxiolytic and antidepressive effect was diminished by co-administration of a TREK-1 blocker, amlodipine, indicating the involvement of TREK-1 channels. Administration of ostruthin suppressed the stress-induced increase in anti-c-Fos immunoreactivity in the lateral septum, without affecting immunoreactivity in other mood disorder-related nuclei, e.g. the amygdala, paraventricular nuclei, and dorsal raphe nucleus. Ostruthin may exert its anxiolytic and antidepressive effects through a different mechanism from current drugs

Characterization of polyphenol oxidase in ginger (Zingiber officinale R.)

A polyphenol oxidase (PPO) isoform that showed expression at all developmental stages of rhizomes in 13 ginger (Zingiber officinale R.) accessions and the only one observed at full maturity of rhizome was characterized. The isoform is a non-covalent homo-dimeric protein of 66 kDa subunits. The native molecular mass was estimated at ~127 kDa using non- reducing SDS–PAGE (10%). Its activity after purification was confirmed by substrate staining both in native gel (7%) and non-reducing SDS gel (10%). The N-terminal amino acid sequence of the subunit of ginger rhizome polyphenol oxidase is ‘Glu-Gln-Gly-Val-Gly-Gly-Asp-Asp-Gly-Leu-.’ The enzyme showed maximum activity at pH 4.5 and 60°C. The PPO is thermo-tolerant and active in a broad pH range (pH 3.5 to 8). Heat inactivation studies showed a decrease in enzyme activity at 75°C and above. Lower concentrations of MgCl2 (1 mM) and CaCl2 (0.5 mM) activated the enzyme whereas higher concentrations (10 mM) reduced the activity. L- Cysteine HCl, L-ascorbic acid, potassium metabisulfite and NaCl inhibited PPO strongly. Western blot analysis of crude leaf extracts with polyclonal antiserum raised against purified PPO confirmed absence of its expression in leaves at different stages of development. Polyclonal anti-PPO antiserum cross reacted with Solanum tuberosum, Raphanus sativus and Dioscorea esculenta tuber extracts and Solanum melongena, Malus sylvestris and Musa paradisiaca fruit extracts but no cross reactivity was observed with Curcuma amada and Ipomoea batatas extracts. &nbsp

Characterization of polyphenol oxidase in ginger (Zingiber officinale R.)

A polyphenol oxidase (PPO) isoform that showed expression at all developmental stages of rhizomes in 13 ginger (Zingiber officinale R.) accessions and the only one observed at full maturity of rhizome was characterized. The isoform is a non-covalent homo-dimeric protein of 66 kDa subunits. The native molecular mass was estimated at ~127 kDa using non- reducing SDS–PAGE (10%). Its activity after purification was confirmed by substrate staining both in native gel (7%) and non-reducing SDS gel (10%). The N-terminal amino acid sequence of the subunit of ginger rhizome polyphenol oxidase is ‘Glu-Gln-Gly-Val-Gly-Gly-Asp-Asp-Gly-Leu-.’ The enzyme showed maximum activity at pH 4.5 and 60°C. The PPO is thermo-tolerant and active in a broad pH range (pH 3.5 to 8). Heat inactivation studies showed a decrease in enzyme activity at 75°C and above. Lower concentrations of MgCl2 (1 mM) and CaCl2 (0.5 mM) activated the enzyme whereas higher concentrations (10 mM) reduced the activity. L- Cysteine HCl, L-ascorbic acid, potassium metabisulfite and NaCl inhibited PPO strongly. Western blot analysis of crude leaf extracts with polyclonal antiserum raised against purified PPO confirmed absence of its expression in leaves at different stages of development. Polyclonal anti-PPO antiserum cross reacted with Solanum tuberosum, Raphanus sativus and Dioscorea esculenta tuber extracts and Solanum melongena, Malus sylvestris and Musa paradisiaca fruit extracts but no cross reactivity was observed with Curcuma amada and Ipomoea batatas extracts. &nbsp

Seed germination studies in Garcinia spp

Germination studies conducted at Padannakad (Kerala) on Garcinia gummi-gutta and Garciniacowa indicated that soaking seeds in hydrogen peroxide (30%) for 30 min and overnightsoaking in cow milk and kinetin (500 ppm) were effective in breaking the dormancy of seedsand resulted in 60.05%, 39.96% and 34.41% germination, respectively in G. gummi-gutta and65.33%, 69.33% and 54.67% germination in G. cowa at 7 months after sowing. In Garciniatinctoria, soaking in hydrogen peroxide (30%) for 30 min and overnight soaking in kinetin(500 ppm) and gibberellic acid (500 ppm) induced early germination resulting in 78.6%, 93.3%,and 64.0% germination respectively, at 2 months after sowing. &nbsp

Seroprevalence of Rubella IgG in Women of Reproductive Age Group in a Tertiary Care Teaching Hospital

Rubella is a highly contagious infection caused by the rubella virus. Mothers who develop rubella early in pregnancy have a 90% chance of transmitting the infection to their unborn babies. Adverse effects on the fetus include stillbirth and congenital rubella syndrome. Pregnant women are not regularly screened for rubella antibodies in government hospitals in Kerala. Therefore, to raise awareness of healthcare providers, it is necessary to collect epidemiological data on the seroprevalence of rubella in this vulnerable group. Several sociodemographic variables as potential predictors of immunity to rubella were also analyzed. A cross-sectional descriptive study was conducted at Govt TD Medical College in Alappuzha, Kerala, of 604 women of childbearing potential who attended the Out patient department of the Obstetrics and gynecology division for the year from June 2016 to June 2017. Rubella-specific IgG (Quantitative) ELISA was done on patients after obtaining informed consent and filling out a questionnaire through direct interview. The test sera were considered seropositive (>15 IU/ml), seronegative (<13 IU/ml), or intermediate (13 -15 IU/ml) as per the manufacturer’s instructions. Rubella seroprevalence in the study group was found to be 73.3%. Around 26.65% were nonimmune to rubella infection. About 27.4% of antenatal cases in the present study were susceptible to rubella. The primigravidae had lower seroprevalence(28.5%) than multigravidae. The percentage of seropositivity was found to increase with age. Our observations show that women of childbearing age are highly susceptible to rubella. High seroprevalence without regular childhood vaccination indicates continued infection transmission of the rubella virus in the community. Hence there is a need for proper sero surveillance in this group who has not been vaccinated, before conception to eradicate CRS and Rubella

Rre37 stimulates accumulation of 2-oxoglutarate and glycogen under nitrogen starvation in Synechocystis sp. PCC 6803

AbstractRre37 (sll1330) in a cyanobacterium Synechocystis sp. PCC 6803 acts as a regulatory protein for sugar catabolic genes during nitrogen starvation. Low glycogen accumulation in Δrre37 was due to low expression of glycogen anabolic genes. In addition to low 2-oxoglutarate accumulation, normal upregulated expression of genes encoding glutamate synthases (gltD and gltB) as well as accumulation of metabolites in glycolysis (fructose-6-phosphate, fructose-1,6-bisphosphate, and glyceraldehyde-3-phosphate) and tricarboxylic acid (TCA) cycle (oxaloacetate, fumarate, succinate, and aconitate) were abolished by rre37 knockout. Rre37 regulates 2-oxoglutarate accumulation, glycogen accumulation through expression of glycogen anabolic genes, and TCA cycle metabolites accumulation

Epigenomic regulation of human T-cell leukemia virus by chromatin-insulator CTCF

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes an aggressive T-cell malignancy and a variety of inflammatory conditions. The integrated provirus includes a single binding site for the epigenomic insulator, CCCTC-binding protein (CTCF), but its function remains unclear. In the current study, a mutant virus was examined that eliminates the CTCF-binding site. The mutation did not disrupt the kinetics and levels of virus gene expression, or establishment of or reactivation from latency. However, the mutation disrupted the epigenetic barrier function, resulting in enhanced DNA CpG methylation downstream of the CTCF binding site on both strands of the integrated provirus and H3K4Me3, H3K36Me3, and H3K27Me3 chromatin modifications both up- and downstream of the site. A majority of clonal cell lines infected with wild type HTLV-1 exhibited increased plus strand gene expression with CTCF knockdown, while expression in mutant HTLV-1 clonal lines was unaffected. These findings indicate that CTCF binding regulates HTLV-1 gene expression, DNA and histone methylation in an integration site dependent fashion