Metabolic communication between astrocytes and neurons via bicarbonate-responsive soluble adenylyl cyclase

Astrocytes are proposed to participate in brain energy metabolism by supplying substrates to neurons from their glycogen stores and from glycolysis. However, the molecules involved in metabolic sensing and the molecular pathways responsible for metabolic coupling between different cell types in the brain are not fully understood. Here we show that a recently cloned bicarbonate (HCO₃⁻) sensor, soluble adenylyl cyclase (sAC), is highly expressed in astrocytes and becomes activated in response to HCO₃⁻ entry via the electrogenic NaHCO₃ cotransporter (NBC). Activated sAC increases intracellular cAMP levels, causing glycogen breakdown, enhanced glycolysis, and the release of lactate into the extracellular space, which is subsequently taken up by neurons for use as an energy substrate. This process is recruited over a broad physiological range of [K⁺](ext) and also during aglycemic episodes, helping to maintain synaptic function. These data reveal a molecular pathway in astrocytes that is responsible for brain metabolic coupling to neurons.

Autistic-like behaviour in Scn1a+/- mice and rescue by enhanced GABA-mediated neurotransmission

Haploinsufficiency of the SCN1A gene encoding voltage-gated sodium channel Na_V1.1 causes Dravet Syndrome (DS), a childhood neuropsychiatric disorder including recurrent intractable seizures, cognitive deficit, and autism-spectrum behaviors. The neural mechanisms responsible for cognitive deficit and autism-spectrum behaviors in DS are poorly understood. Here we show that mice with Scn1a haploinsufficiency display hyperactivity, stereotyped behaviors, social interaction deficits, and impaired context-dependent spatial memory. Olfactory sensitivity is retained, but novel food odors and social odors are aversive to Scn1a^+/− mice. GABAergic neurotransmission is specifically impaired by this mutation, and selective deletion of Na_V1.1 channels in forebrain interneurons is sufficient to cause these behavioral and cognitive impairments. Remarkably, treatment with low-dose clonazepam, a positive allosteric modulator of GABA_A receptors, completely rescued the abnormal social behaviors and deficits in fear memory in DS mice, demonstrating that they are caused by impaired GABAergic neurotransmission and not by neuronal damage from recurrent seizures. These results demonstrate a critical role for Na_V1.1 channels in neuropsychiatric functions and provide a potential therapeutic strategy for cognitive deficit and autism-spectrum behaviors in DS.

[Distribution characteristics of polycyclic aromatic hydrocarbons in runoff from the middle line source area of south-to-north water diversion project]

The distribution characteristics of polycyclic aromatic hydrocarbons in runoff from the middle line source area of south-to-north water diversion project were studied. Five groups of artificial runoff fields were established to collect runoff based on the different types of land-use, the contents of 16 USEPA priority PAHs in the runoff were determined using GC/MS method. The results showed that the average concentrations of PAHs of the aqueous phase in the collected runoff samples of different land-use types decreased in the order:cultivated land (26.53 ng x L(-1)) > oak forest (20.91 ng x L(-1)) > orchard (17.59 ng x L(-1)), and the average concentrations of PAHs of the particle phase were cultivated land (1 073.72 ng x g(-1)) > orchard (652.29 ng x g(-1)) > oak forest (385.46 ng x g(-1)). The high carcinogenic components Bap were detected in both run off of cultivated land and orchard with a detected rate of 30%. According to National Recommended Water Quality Standards of priority toxic pollutants (2006 USEPA), it was found that Chr exceed standard 40%, with a detected rate of 100%. It was also found that the runoff volume and the total PAHs content in runoff increase with the slope, and PAHs loss and slope were closely related in same land-use types. Based on the Molecular Markers Indicative Law, it can be concluded that the dominant source of PAHs in runoff of study area was combustion of coal, and a small amount came from vehicle exhaust emissions. There is a certain degree of ecological risk about runoff PAHs pollution in the study area, which is worth further attention.

Two-stage utilization of corn straw by Rhizopus oryzae for fumaric acid production

Due to the abundant, low price characteristic, lots of efforts have been put into producing bulk chemical from lignocellulose biomass, but the low utility of xylose, which is the second main component in lignocellulose, becomes a bottleneck for efficient lignocellulose utilization. This study investigated a novel two-stage corn straw utilization strategy for fumaric acid production by Rhizopus oryzae. Fungal growth was approached in hydrolysates from acid hydrolysis of corn straw, contained 30 g/l xylose; and fumaric acid production was occurred in hydrolysates from enzymatic hydrolysis of the residue corn straw after acid hydrolysis, contained 80 g/l glucose. Under the optimal condition using this two-stage corn straw utilization strategy, the fumaric acid production, was up to 27.79 g/l, with the yield of 0.35 g/g, productivity of 0.33 g/l/h.

Chitosan production from hemicellulose hydrolysate of corn straw: impact of degradation products on Rhizopus oryzae growth and chitosan fermentation

AIMS

To examine the potential use of hemicellulose hydrolysate (HH) for the production of chitosan by Rhizopus oryzae and investigate the influence of contents in HH on mycelia growth and chitosan synthesis.

METHODS AND RESULTS

Compared to xylose medium, HH enhanced mycelia growth, chitosan content and production of R. oryzae by 10.2, 64.5 and 82.1%, respectively. During sulfuric acid hydrolysis of corn straw, sugars (glucose, galactose, etc) and inhibitors (formic acid, acetic acid and furfural) were generated. Acetic acid (2.14 g l(-1)) and formic acid (0.83 g l(-1)) were stimulative, while furfural (0.55 g l(-1)) was inhibitory. Inhibitors, at different concentrations, increased the mycelia growth and chitosan production by 24.5-37.8 and 60.1-207.1%.

CONCLUSIONS

HH of corn straw is a good source for chitosan production. Inhibitors in HH, at proper concentrations, can enhance chitosan production greatly.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work for the first time reported chitosan production from HH. Chitosan production can be greatly enhanced by cheap chemicals such as inhibitors in HH.

Efficacy and Safety Data of Taiwan Breast Cancer Patients Enrolled in the Lapatinib Expanded Access Program (LEAP)

Background: LEAP is a single-arm, open-label, expanded access study of lapatinib in combination with capecitabine in 42 countries. The primary objective of LEAP was to provide patients with pre-approval access to lapatinib based on positive clinical data from a pivotal Phase III trial.Methods: Enrolled patients had locally advanced or HER2 positive metastatic breast cancer (MBC), progressive disease (PD, by modified RECIST) following prior therapy with anthracycline-, taxane-, and trastuzumab-containing regimens, including some patients previously treated with capecitabine, and were ineligible for ongoing lapatinib trials. Patients received lapatinib (1250 mg/day) and capecitabine (2000 mg/m2/day, days 1-14, every 21 days). Baseline characteristics, including prior therapies, were collected. Response was assessed using RECIST criteria.Results: From Mar 2007 to Sep 2008, 238 patients were enrolled at 10 centers in Taiwan. At the 11 June 2009 data cut-off, data were collected and analyzed for 166 patients. Patients received an average of 5 prior cytotoxic therapies, including trastuzumab and capecitabine.Of 166 patients, 3 (2%) had complete response, 49 (30%) had partial response, 62 (37%) had stable disease, 42 (25%) had PD, and 10 (6%) were unknown. The median duration of treatment was 5.5 mo and the median time to progression was 5.3 mo, respectively. Per protocol, only serious adverse events (SAEs) were reported. Thirty SAEs were reported for 238 patients; 6 (20%) were considered treatment-related by investigators, were not fatal, and included stomatitis (2), vomiting (2), diarrhea (1), and cellulitis (1). As of 11 June 2009, 66 (40%) patients were alive and 149 withdrew from LEAP, the majority (85%) because of progressive disease.Conclusion: Although data were collected retrospectively via case report forms, these results reflect the real world setting in Taiwan for the treatment of erbB2+ MBC patients and confirms that lapatinib, in combination with capecitabine, demonstrates efficacy in this patient population including those who are heavily pretreated.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5093.

[Distribution characteristics of organochlorine pesticides in surface water and sediments from the Mengjin wetland]

The surface water and sediments from the Mengjin wetland were collected. After seperated and concentrated by solid phase extraction and Soxhlet extraction, twenty kinds of organochlorine pesticides (OCPs) in the samples from the Mengjin wetland were analyzed by gas chromatography. In the surface water, 7 kinds of OCPs (incluing alpha-HCH, beta-HCH, gamma-HCH, delta-HCH, 4,4-DDT, heptachor and aldrin) were detected, with the detected ratio of 4.2% -62.5% and the content range of ND-12.21 ng/L. In the sediments, 4,4-DDE and 4,4-DDT were detected, with the detected ratio of 50%-75% and the content range of ND-64.58 ng/g. HCHs and DDTs in the surface water were both lower than the limited value defined by Environmental Quality Standards for Surface Water in China, while the surface sediments in the Mengjin wetland pose a bit high risk comparing with ERL and ERM value of risk evaluation. Distribution characteristics of OCPs components showed that HCHs usually had higher residue levels in surface water, while sediment was the fate of DDTs in the transfer process of materials from water to sediment. OCPs content in the surface water and sediments both decreased in the order of high water period > level water period > low water period. OCPs in the low water seasons were mainly the early residue, but OCPs in the high seasons had some new input in near term in the surface water and sediments. The results suggested that non-point source was one of the important sources of OCPs entering Mengjin wetland.

Agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetlands: a case study in the Yellow River wetland in China

Riparian wetland is the major transition zone of matter, energy and information transfer between aquatic and terrestrial ecosystems and has important functions of water purification and non-point pollution control. Using the field experiment method and an isotope tracing technique, the agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetland was studied in the Kouma Section of the Yellow River. The results showed that the retention of agricultural non-point nitrogen pollution by riparian wetland soil occurs mainly in top 0-10 cm layer. The amount of nitrogen retained by surface soils associated with three types of vegetation are 0.045 mg/g for Phragmites communis Trin Linn, 0.036 mg/g for Scirpus triqueter Linn, and 0.032 mg/g for Typha angustifolia Linn, which account for 59.21%, 56.25%, and 56.14% of the total nitrogen interception, respectively. Exogenous nitrogen in 0-10 cm soil layer changes more quickly than in other layers. One month after adding K(15)NO3 to the tested vegetation, nitrogen content was 77.78% for P. communis Trin, 68.75% for T. angustifolia, and 8.33% for S. triqueter in the surface soil. After three months, nitrogen content was 93.33% for P. communis Trin, 72.22% for S. triqueter, and 37.50% for T. Angustifolia. There are large differences among vegetation communities respecting to purification of agricultural non-point nitrogen pollution. The nitrogen uptake amount decreases in the sequence: new shoots of P. communis Trin (9.731 mg/g) > old P. communis Trin (4.939 mg/g) > S. triqueter (0.620 mg/g) > T. angustifolia (0.186 mg/g). Observations indicated that the presence of riparian wetlands as buffers on and adjacent to stream banks could be recommended to control agricultural non-point pollution.

Glutamatergic stimulation triggers rapid Krüpple-like factor 4 expression in neurons and the overexpression of KLF4 sensitizes neurons to NMDA-induced caspase-3 activity

We report the first demonstration that Krüpple-like factor 4 (KLF4) mRNA is dramatically and rapidly upregulated by NMDA application in primary cortical neuron cultures. We also report that NMDA induced significant and transient upregulation of KLF4 protein expression, in both cortical neuron cultures and native brain slices. The increase of KLF4 mRNA and protein expression in response to NMDA was time-dependent, and required NMDA receptor-mediated Ca(2+) influx. In addition, AMPA exposure caused a time-dependent increase in KLF4 mRNA expression, which was also Ca(2+)-dependent and involved activation of AMPA/kainate receptors and L-type voltage-sensitive calcium channels. To assess the downstream signaling pathways and functions of KLF4 activation, we used lentiviral vectors to induce ectopic overexpression of KLF4 in cultured neurons. KLF4 overexpression induced the activation of caspase-3 after a normally subtoxic dose of NMDA (10 microM). KLF4 overexpression also increased both protein and mRNA levels of the cell cycle protein cyclin D1, but reduced p21(Waf1/Cip1) protein levels. After the NMDA treatment, cyclin D1 levels increased after a short delay (4 h), but fell back to control levels after 20 h. The effects of NMDA and KLF4 overexpression on cyclin D1 induction were additive. We conclude that glutamatergic stimulation can trigger rapid elevation of KLF4 mRNA and protein levels, and that the overexpression of KLF4 can regulate neuronal cell cycle proteins and sensitize neurons to NMDA-induced caspase-3 activity.

Debromination of decabrominated diphenyl ether by resin-bound iron nanoparticles

Nanoscale zerovalent iron, n-ZVI, was found to be highly effective in reductively debrominating decabromodiphenyl ether (BDE209) at ambient conditions and without the catalysis of noble metals. A method was developed to immobilize n-ZVI particles on a cation-exchange resin. The n-ZVI coated resin was then mixed with BDE209 in a water/ acetone (1:1) solution, and the reaction was allowed to proceed for up to 10 days. The first-order rate constant of BDE209 disappearance was estimated to be 0.28 - 0.04 h(-1). The debromination was found to be stepwise, and less-brominated congeners were produced with increasing reaction time. Dechlorination of decachlorobiphenyl (PCB209) was also investigated, but the reaction rate was much slower than the debromination of BDE209. Identification of the reaction products was highly challenging and was assisted by regression equations between experimental and reference gas chromatographic relative retention times, with confirmation by high-resolution mass spectrometry and reference to quantitative structure retention relationships. For randomly selected PBDE and PCB congeners, the net charges of individual atoms were calculated using the quantum chemical computation to explore the difference in relative vulnerability of halogens at different substitution positions between PBDEs and PCBs.

Origin of spontaneous activity in neonatal and adult rat bladders and its enhancement by stretch and muscarinic agonists

This study examined the origin of spontaneous activity in neonatal and adult rat bladders and the effect of stretch and muscarinic agonists and antagonists on spontaneous activity. Rats were anesthetized and their bladders were excised, cannulated, and loaded with voltage- and Ca(2+)-sensitive dyes. Intracellular Ca(2+) and membrane potential transients were mapped using photodiode arrays in whole bladders, bladder sheets, or cross-section preparations at 37 degrees C. Intravesical pressure was recorded from whole bladders. In neonatal bladders and sheets, spontaneous Ca(2+) and electrical signals arose at a site near the dome and spread in a coordinated manner throughout the bladder with different dome-to-neck conduction velocities (Ca(2+): 3.7 +/- 0.4 mm/s; membrane potential: 46.2 +/- 3.1 mm/s). In whole bladders, optical signals were associated with spontaneous contractions (10-20 cmH(2)O). By contrast, in adult bladders spontaneous Ca(2+) and electrical activity was uncoordinated, originating at multiple sites and was associated with smaller (2-5 cmH(2)O) contractions. Spontaneous contractions and optical signals were insensitive to tetrodotoxin (2 muM) but were blocked by nifedipine (10 muM). Stretch or low carbachol concentrations (50 nM) applied to neonatal whole bladders enhanced the amplitude (to 20-35 cmH(2)O) of spontaneous activity, which was blocked by atropine. Bladder cross sections revealed that Ca(2+) and membrane potential transients produced by stretch or carbachol began near the urothelial-suburothelial interface and then spread to the detrusor. In conclusion, spontaneous activity in neonatal bladders, unlike activity in adult bladders, is highly organized, originating in the urothelium-suburothelium near the dome. Activity is enhanced by stretch or carbachol and this enhancement is blocked by atropine. It is hypothesized that acetylcholine is released from the urothelium during bladder filling to enhance spontaneous activity.

Selection responses in duration of fertility and its consequences on hatchability in the intergeneric crossbreeding of ducks

1. From 1992 to 2003, selected (S) and control lines (C) of the laying Brown Tsaiya duck (Anas platyrhynchos) were simultaneously maintained under the same standardised conditions of feeding and management. 2. The selection objective was to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. From generations G1 to G11, 2452 and 2022 female ducks, in S and C lines, respectively, were measured and recorded. In the S line, the percentage selected varied between 20.2 and 34.3% in females and between 7.2 and 20.8% in males. 3. Selection for number of fertile eggs had a correlated effect of increasing the parameter tau of the logistic curves which fitted the daily variations (d 2 to 15) in fertility or hatchability on the basis of eggs set. The differences S-C for the estimates of the times of half maximal fertility and hatchability increased by 0.41 and 0.37 d per generation between G1 and G11, respectively. 4. The highest increases of fertility per day rates after a single AI were observed between d 5 and 11. Moreover, in the selected line, fertility rate was higher than, or equal to, 90% in d 2 from G8. The same tendencies were observed for the changes in the evolution of hatchability on the basis of eggs set. 5. Selection increased fertility and hatchability according to the egg set rates, especially for d 2 to 8 after AI. Hatchability of fertile eggs was not impaired, confirming that selection for one AI per week was possible in this strain of laying ducks.

Muscarinic enhancement of R-type calcium currents in hippocampal CA1 pyramidal neurons

The "toxin-resistant" R-type Ca2+ channels are expressed widely in the CNS and distributed mainly in apical dendrites and spines. They play important roles in regulating signal transduction and intrinsic properties of neurons, but the modulation of these channels in the mammalian CNS has not been studied. In this study we used whole-cell patch-clamp recordings and found that muscarinic activation enhances R-type, but does not affect T-type, Ca2+ currents in hippocampal CA1 pyramidal neurons after N, P/Q, and L-type Ca2+ currents selectively were blocked. M1/M3 cholinergic receptors mediated the muscarinic stimulation of R-type Ca2+ channels. The signaling pathway underlying the R-type enhancement was independent of intracellular [Ca2+] changes and required the activation of a Ca(2+)-independent PKC pathway. Furthermore, we found that the enhancement of R-type Ca2+ currents resulted in the de novo appearance of Ca2+ spikes and in remarkable changes in the firing pattern of R-type Ca2+ spikes, which could fire repetitively in the theta frequency. Therefore, muscarinic enhancement of R-type Ca2+ channels could play an important role in modifying the dendritic response to synaptic inputs and in the intrinsic resonance properties of neurons.

Interleukin-1beta downregulates the L-type Ca2+ channel activity by depressing the expression of channel protein in cortical neurons

Interleukin-1beta (IL-1beta), a proinflammatory cytokine, has been involved in various diseases of the central nervous system (CNS). Due to the diverse, "contradictory" effects of IL-1beta on neurons during insults to the brain, the mechanisms underlying these effects have not been elucidated. Calcium influx through the L-type Ca2+ channels (LCCs) is believed to play a critical role in the cascade of biochemical events leading to neuron death in these pathophysiological conditions. So far, the mechanism of the interaction of IL-1beta and LCCs in the initiation and progression of these diseases is unclear. In this study, we investigate systemically the effects of IL-1beta on the LCCs current, which are believed to be implicated in the cascade of biochemical events leading to neuron death in neuropathological conditions. Using patch clamp, we observe that IL-1beta treatment (10 ng/ml, 24 h) suppresses LCC currents by approximately 38%, which made up half of the whole-cell Ca2+ current determined by nifedipine. IL-1beta does not alter the characteristics of single LCC including current amplitude, open probability, and conductance, but decreases the number of the functioning channel by 40%. Moreover, immunoblot assay exhibits that IL-1beta reduces the expression of LCC proteins by 38 approximately 42% in both whole neuron and plasma membrane fraction, and demonstrates that IL-1beta downregulates the LCC activity via the reduction of LCC density. According to early research pretreatments longer than 12 h may play a crucial role in the neuroprotective effects of IL-1beta, our findings may establish an explanation for the protective effects of this interleukin on neurons in the late stage of injury, and could raise a new issue to clinical treatment for insults to brain.

Ionic liquid for high temperature headspace liquid-phase microextraction of chlorinated anilines in environmental water samples

Based on the non-volatility of room temperature ionic liquids (IL), 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) IL was employed as an advantageous extraction solvent for high temperature headspace liquid-phase microextraction (LPME) of chloroanilines in environmental water samples. At high temperature of 90 degrees C, 4-chloroaniline, 2-chloroaniline, 3,4-dichloroaniline, and 2,4-dichloroaniline were extracted into a 10 microl drop of [C4MIM][PF6] suspended on the needle of a high-performance liquid chromatography (HPLC) microsyringe held at the headspace of the samples. Then, the IL was injected directly into the HPLC system for determination. Parameters related to LPME were optimized, and high selectivity and low detection limits of the four chlorinated anilines were obtained because the extraction was performed at high temperature in headspace mode and the very high affinity between IL and chlorinated anilines. The proposed procedure was applied for the analysis of the real samples including tap water, river water and wastewater samples from a petrochemical plant and a printworks, and only 3,4-dichloroaniline was detected in the printworks wastewater at 88.2 microg l(-1) level. The recoveries for the four chlorinated anilines in the four samples were all in the range of 81.9-99.6% at 25 microg l(-1) spiked level.

Dechlorination and destruction of 2,4,6-trichlorophenol and pentachlorophenol using hydrogen peroxide as the oxidant catalyzed by molybdate ions under basic condition

The dechlorination and destruction of 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) under basic condition using hydrogen peroxide as the oxidant catalyzed by molybdate ions have been studied. Under ambient conditions of temperature and pressure, more than 95% of millimolar solutions of TCP and PCP can be converted to CO2 and CO, chlorinated and nonchlorinated carboxylic acid in 40 min. Up to 2.4 chloride ions per TCP and 3.5 chloride ions per PCP were released. TOC measurements indicated that 18% and 11% of the carbon was mineralized for TCP and PCP respectively after an hour of reaction. The results of ESR measurements suggested that the reaction possibly proceeded via the pathway with singlet oxygen.