Impact of correlated inputs to neurons: modeling observations from in vivo intracellular recordings

In vivo recordings in rat somatosensory cortex suggest that excitatory and inhibitory inputs are often correlated during spontaneous and sensory-evoked activity. Using a computational approach, we study how the interplay of input correlations and timing observed in experiments controls the spiking probability of single neurons. Several correlation-based mechanisms are identified, which can effectively switch a neuron on and off. In addition, we investigate the transfer of input correlation to output correlation in pairs of neurons, at the spike train and the membrane potential levels, by considering spike-driving and non-spike-driving inputs separately. In particular, we propose a plausible explanation for the in vivo finding that membrane potentials in neighboring neurons are correlated, but the spike-triggered averages of membrane potentials preceding a spike are not: Neighboring neurons possibly receive an ongoing bombardment of correlated subthreshold background inputs, and occasionally uncorrelated spike-driving inputs.     

Gender Difference in the Association of Metabolic Syndrome and Its Components with Age-Related Cataract: The Korea National Health and Nutrition Examination Survey 2008-2010

Purpose

To explore the relationship of the metabolic syndrome (MetS) and its components with age-related cataract in a representative Korean population.

Methods

We analyzed the data from the Korea National Health and Nutrition Examination Surveys (2008–2010). A total of 11,076 adults (4,811 men and 6,265 women) aged 40 and over who completed ophthalmologic examination were evaluated. Cataract was defined as the presence of cortical, nuclear, anterior (sub)capsular or posterior subcapsular cataract, from slit-lamp examination or previous cataract surgery. MetS was defined according to the Joint Interim Statement proposed in 2009 from the International Diabetes Federation and the American Heart Association/National Heart, Lung, and Blood Institute.

Results

The prevalence of cataract and MetS in this population was 39.4% (37.1% for men and 41.6% for women) and 38.5% (37.6% for men and 39.4% for women), respectively. Cataract prevalence tended to increase with the number of MetS components in both genders (both P< 0.001). After being controlled for confounders, however, MetS was significantly associated with cataract only in women (adjusted odds ratio (aOR), 1.24; 95% confidence interval (CI), 1.02–1.50]. Reduced HDL cholesterol, elevated fasting glucose, and elevated triglycerides were also significantly associated with cataract in women (aOR, 95% CI; 1.27 (1.07–1.50), 1.23 (1.01–1.50), and 1.26 (1.04–1.52), respectively). In the subgroup analysis for cataract subtype, MetS and reduced HDL cholesterol were significantly associated with nuclear cataract in women (aOR, 95% CI; 1.25 (1.07–1.55) and 1.25 (1.03–1.52), respectively). However, such associations were not found in men.

Conclusions

Our results suggest that MetS and its components appear to be associated with age-related cataract only among Korean women, especially in nuclear cataract.     

Regulation of the final stage of mitosis by components of the pre-replicative complex and a polo kinase

The accurate division of duplicated DNA is essential for maintenance of genomic stability in proliferating eukaryotic cells. Errors in DNA replication and chromosomal segregation may lead to cell death or genomic mutations that lead to oncogenic properties. Thus, tight regulation of DNA replication and mitosis is essential for maintaining genomic integrity. Cell division cycle 6 (Cdc6) is an essential factor for initiating DNA replication. Recent work shows that phosphorylation of Cdc6 by pololike kinase 1 (Plk1), one of the essential mitotic kinases, regulates mitotic exit mediated by Cdk1 and separase. Here we discuss how pre-replicative complex factors are connected with Plk1 and affect mitotic exit.Key words: Plk1, Cdc6, DNA replication, mitotic exit, chromosomal segregation     

Callose Deposition Is Responsible for Apoplastic Semipermeability of the Endosperm Envelope of Muskmelon Seeds

Semipermeable cell walls or apoplastic “membranes” have been hypothesized to be present in various plant tissues. Although often associated with suberized or lignified walls, the wall component that confers osmotic semipermeability is not known. In muskmelon (Cucumis melo L.) seeds, a thin, membranous endosperm completely encloses the embryo, creating a semipermeable apoplastic envelope. When dead muskmelon seeds are allowed to imbibe, solutes leaking from the embryo are retained within the envelope, resulting in osmotic water uptake and swelling called osmotic distention (OD). The endosperm envelope of muskmelon seeds stained with aniline blue, which is specific for callose (β-1,3-glucan). Outside of the aniline-blue-stained layer was a Sudan III- and IV-staining (lipid-containing) layer. In young developing seeds 25 d after anthesis (DAA) that did not exhibit OD, the lipid layer was already present but callose had not been deposited. At 35 DAA, callose was detected as distinct vesicles or globules in the endosperm envelope. A thick callose layer was evident at 40 DAA, coinciding with development of the capacity for OD. Removal of the outer lipid layer by brief chloroform treatment resulted in more rapid water uptake by both viable and nonviable (boiled) seeds, but did not affect semipermeability of the endosperm envelope. The aniline-blue-staining layer was digested by β-1,3-glucanase, and these envelopes lost OD. Thus, apoplastic semipermeability of the muskmelon endosperm envelope is dependent on the deposition of a thick callose-containing layer outside of the endosperm cell walls.     

LSD and phenithylamine hallucinogens: New structural analogy and implications for receptor geometry

The hallucinogen analog $\text{trans}$-2-(2,5-dimethoxy-4-methylphenyl)-cyclopropylamine (DMCPA) was resolved into its two optical isomers. Examination of selected behavioral profiles in mice and cats clearly showed that the levorotatory isomer of DMCPA possesses stereoselective activity when compared with the dextro isomer. The results parallel those obtained using the isomers of the known hallucinogen, DOM (STP) in the same animal models. Comparison of the optical rotatory dispersion (ORD) curves for the N-(5-bromosalicylidene) derivatives of DMCPA and $\text{trans}$-2-phenylcyclopropylamine (tranylcypromine) of known absolute configuration established the configuration of DMCPA to be (-)-1R,2S. This stereoselective activity and proof of absolute configuration lend strong support to a new model of the hallucinogen receptor. The proposed model suggests possible structural similarities between LSD and phenethylamine hallucinogens.     

Revisiting the use of Iprodione and Trichoderma in the integrated management of onion white rot

The biocontrol properties of Trichoderma species are well documented, but their effectiveness in antagonism of the problematic Sclerotium cepivorum, the causal agent of white rot in Allium species, appears limited with reports of significant control only relating to deliberately-mutated strains of Trichoderma. Our previous studies have indicated the possibility of using selected naturally-occurring strains of the antagonist in the suppression of other diseases; now in vitro and controlled environment in vivo studies have indicated that a degree of control of Onion White Rot is possible, and that the selected antagonist strains can be used in integrated treatments with Iprodione to good effect. The possible value of such treatments is considered in light of other approaches to the suppression of this continuing problem.