Modulation of human time processing by subthalamic deep brain stimulation

Timing in the range of seconds referred to as interval timing is crucial for cognitive operations and conscious time processing. According to recent models of interval timing basal ganglia (BG) oscillatory loops are involved in time interval recognition. Parkinsońs disease (PD) is a typical disease of the basal ganglia that shows distortions in interval timing. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a powerful treatment of PD which modulates motor and cognitive functions depending on stimulation frequency by affecting subcortical-cortical oscillatory loops. Thus, for the understanding of BG-involvement in interval timing it is of interest whether STN-DBS can modulate timing in a frequency dependent manner by interference with oscillatory time recognition processes. We examined production and reproduction of 5 and 15 second intervals and millisecond timing in a double blind, randomised, within-subject repeated-measures design of 12 PD-patients applying no, 10-Hz- and ≥ 130-Hz-STN-DBS compared to healthy controls. We found under(re-)production of the 15-second interval and a significant enhancement of this under(re-)production by 10-Hz-stimulation compared to no stimulation, ≥ 130-Hz-STN-DBS and controls. Milliseconds timing was not affected. We provide first evidence for a frequency-specific modulatory effect of STN-DBS on interval timing. Our results corroborate the involvement of BG in general and of the STN in particular in the cognitive representation of time intervals in the range of multiple seconds.     

DNA algorithm for an unbounded fan-in Boolean circuit

In this paper, we present a new DNA-based evaluation algorithm for a Boolean circuit that employs standard bio-molecular techniques. The algorithm operates on an unbounded fan-in Boolean circuit consisting of AND and OR gates. The whole simulation of our algorithm is proposed in a single test tube in O(1) time complexity and is much easier to implement in the laboratory than previously described models. Furthermore, the algorithm allows for evaluating any number of Boolean circuits in parallel in a single test tube.     

Fed-batch Cultivation of Mucor indicus in Dilute-acid Lignocellulosic Hydrolyzate for Ethanol Production

Mucor indicus fermented dilute-acid lignocellulosic hydrolyzates to ethanol in fed-batch cultivation with complete hexose utilization and partial uptake of xylose. The fungus was tolerant to the inhibitors present in the hydrolyzates. It grew in media containing furfural (1 g/l), hydroxymethylfurfural (1 g/l), vanillin (1 g/l), or acetic acid (7 g/l), but did not germinate directly in the hydrolyzate. However, with fed-batch methodology, after initial growth of M. indicus in 500 ml enzymatic wheat hydrolyzate, lignocellulosic hydrolyzate was fermented with feeding rates 55 and 100 ml/h. The fungus consumed more than 46% of the initial xylose, while less than half of this xylose was excreted in the form of xylitol. The ethanol yield was 0.43 g/g total consumed sugar, and reached the maximum concentration of 19.6 g ethanol/l at the end of feeding phase. Filamentous growth, which is regarded as the main obstacle to large-scale cultivation of M. indicus, was avoided in the fed-batch experiments.     

NAD(P)H oxidase/nitric oxide interactions in peroxisome proliferator activated receptor (PPAR)alpha-mediated cardiovascular effects

Activation of peroxisome proliferator activated receptor (PPAR)alpha and its protective role in cardiovascular function has been reported but the exact mechanism(s) involved is not clear. As we have shown that PPARalpha ligands increased nitric oxide (NO) production and cardiovascular function is controlled by a balance between NO and free radicals, we hypothesize that PPARalpha activation tilts the balance between NO and free radicals and that this mechanism defines the protective effects of PPARalpha ligands on cardiovascular system. Systolic blood pressure (SBP) was greater in PPARalpha knockout (KO) mice compared with its wild type (WT) litter mates (130+/-10 mmHg versus 107+/-4 mmHg). L-NAME (100mg/L p.o.), the inhibitor of NO production abolished the difference between PPARalpha KO and WT mice. In kidney homogenates, tissue lipid hydroperoxide generation was greater in KO mice (11.8+/-1.4 pM/mg versus 8.3+/-0.6 pM/mg protein). This was accompanied by a higher total NOS activity (46+/-6%, p<0.05) and a approximately 3 fold greater Ca2+-dependent NOS activity in kidney homogenates of untreated PPARalpha WT compared with the KO mice. Clofibrate, a PPARalpha ligand, increased NOS activity in WT but not KO mice. Bezafibrate (30 mg/kg) reduced SBP in conscious rats (19+/-4%, p<0.05), increased urinary NO excretion (4.06+/-0.53-7.07+/-1.59 microM/24 h; p<0.05) and reduced plasma 8-isoprostane level (45.8+/-15 microM versus 31.4+/-8 microM), and NADP(H) oxidase activity (16+/-5%). Implantation of DOCA pellet (20mg s.c.) in uninephrectomized mice placed on 1% NaCl drinking water increased SBP by a margin that was markedly greater in KO mice (193+/-13 mmHg versus 130+/-12 mmHg). In the rat, DOCA increased SBP and NAD(P)H oxidase activity and both effects were diminished by clofibrate. In addition, clofibrate reduced ET-1 production in DOCA/salt hypertensive rats. Thus, apart from inhibition of ET-1 production, PPARalpha activation exerts protective actions in hypertension via a mechanism that involves NO production and/or inhibition of NAD(P)H oxidase activity.     

The structure and function of the outer coat protein VP9 of Banna virus

Banna virus (BAV: genus Seadornavirus, family Reoviridae) has a double-shelled morphology similar to rotavirus and bluetongue virus. The structure of BAV outer-capsid protein VP9 was determined by X-ray crystallography at 2.6 A resolution, revealing a trimeric molecule, held together by an N-terminal helical bundle, reminiscent of coiled-coil structures found in fusion-active proteins such as HIV gp41. The major domain of VP9 contains stacked beta sheets with marked structural similarities to the receptor binding protein VP8 of rotavirus. Anti-VP9 antibodies neutralize viral infectivity, and, remarkably, pretreatment of cells with trimeric VP9 increased viral infectivity, indicating that VP9 is involved in virus attachment to cell surface and subsequent internalization. Sequence similarities were also detected between BAV VP10 and VP5 portion of rotavirus VP4, suggesting that the receptor binding and internalization apparatus, which is a single gene product activated by proteoloysis in rotavirus, is the product of two separate genome segments in BAV.     

3-Hydrogenkwadaphnin targets inosine 5'-monophosphate dehydrogenase and triggers post-G1 arrest apoptosis in human leukemia cell lines

3-Hydrogenkwadaphnin (3-HK) is a recently characterized daphnane-type compound isolated from Dendrostellera lessertii with high anti-tumor activity in animal models. Herein, we report on time- and dose-dependent effects of this compound on growth, differentiation, IMPDH inhibition, cell cycle and apoptosis of a panel of human leukemia cell lines (HL-60, K562 and Molt4). The drug decreased the growth of leukemia cells in less than 24 h of treatment. However, longer exposure times and/or higher concentrations were required to promote cell apoptosis. Cell cycle analysis revealed the accumulation of cells in their G1 phase as early as 12 h after drug exposure but sub-G1 population was recorded after 24 h. Occurrence of apoptosis was constantly accompanied by morphological (staining with DNA-binding dyes) and biochemical (DNA fragments) variations among drug-treated cells. Despite these observations, non-activated normal human PBL were insensitive to the drug action. In addition, treatment of PHA-activated PBL, K562, Molt4 and HL-60 cells with a single dose of the drug for 24 h led to the inhibition of IMPDH activity by almost 37, 38, 44 and 50%, respectively. In contrast, no difference in IMPDH activities were seen between normal PBL and the drug treated PBL cells. Restoration of the depleted GTP concentration by exogenous addition of guanosine (25-50 microM) reversed the drug effects on cell growth, DNA fragmentation and apoptosis. Furthermore, the drug effects were potentiated by exogenous addition of hypoxanthine to the drug-treated cells. Reduction of the drug potency on the non-proliferative (retinoic acid treated) HL-60 cells by almost 40%, compared to the proliferative cells, clearly shows type II IMPDH as one of the main targets of the drug. These results suggest that 3-HK may be a powerful candidate for treatment of leukemia.     

Uncoupling of longevity and paraquat resistance in mutants of the nematode Caenorhabditis elegans

To analyze the relationship between resistance to oxidative stress and longevity, we isolated three novel paraquat-resistant mutants, mev-5, mev-6, and mev-7, from the nematode Caenorhabditis elegans. They all showed the Dyf (defective in dye filling) phenotype, but not always resistance to heat or UV. Life-span extension was observed only in the mev-5 mutant at 26 degrees C. These results indicate that longevity is uncoupled with the phenotype of paraquat resistance.