Imaging of Evoked Cortical Depolarizations Using Either ASAP2s, or chi-VSFP, or Di-4-Anepps, or Autofluorescence Optical Signals.

BACKGROUND: Population voltage imaging is used for studying brain physiology and brain circuits. Using a genetically encoded voltage indicator (GEVI), "VSFP" or "ASAP2s", or a voltage-sensitive dye, Di-4-Anepps, we conducted population voltage imaging in brain slices. The resulting optical signals, optical local field potentials (LFPs), were used to evaluate the performances of the 3 voltage indicators. METHODS: In brain slices prepared from VSFP-transgenic or ASAP2s-transgenic mice, we performed multi-site optical imaging of evoked cortical depolarizations - compound excitatory postsynaptic potentials (cEPSPs). Optical signal amplitudes (ΔF/F) and cEPSP decay rates (OFF rates) were compared using analysis of variance (ANOVA) followed by unpaired Student's t test (31-104 data points per voltage indicator). RESULTS: The ASAP2s signal amplitude (ΔF/F) was on average 3 times greater than Di-4-Anepps, and 7 times greater than VSFP. The optical cEPSP decay (OFF rate) was the slowest in Di-4-Anepps and fastest in ASAP2s. When ASAP2s expression was weak, we observed slow, label-free (autofluorescence, metabolic) optical signals mixed into the ASAP2s traces. Fast hyperpolarizations, that typically follow depolarizing cortical transients (afterhyperpolarizations), were prominent in ASAP2s but not present in the VSFP and Di-4-Anepps experiments. CONCLUSIONS: Experimental applications for ASAP2s may potentially include systems neuroscience studies that require voltage indicators with large signal amplitude (ΔF/F), fast decay times (fast response time is needed for monitoring high frequency brain oscillations), and/or detection of brain patches in transiently hyperpolarized states (afterhyperpolarization).

Na+-K+-Cl- cotransporter (NKCC) maintains the chloride gradient to sustain pacemaker activity in interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) generate electrical slow waves by coordinated openings of ANO1 channels, a Ca2+-activated Cl- (CaCC) conductance. Efflux of Cl- during slow waves must be significant, as there is high current density during slow-wave currents and slow waves are of sufficient magnitude to depolarize the syncytium of smooth muscle cells and PDGFRα+ cells to which they are electrically coupled. We investigated how the driving force for Cl- current is maintained in ICC. We found robust expression of Slc12a2 (which encodes an Na+-K+-Cl- cotransporter, NKCC1) and immunohistochemical confirmation that NKCC1 is expressed in ICC. With the use of the gramicidin permeabilized-patch technique, which is reported to not disturb [Cl-]i, the reversal potential for spontaneous transient inward currents (ESTICs) was -10.5 mV. This value corresponds to the peak of slow waves when they are recorded directly from ICC in situ. Inhibition of NKCC1 with bumetanide shifted ESTICs to more negative potentials within a few minutes and reduced pacemaker activity. Bumetanide had no direct effects on ANO1 or CaV3.2 channels expressed in HEK293 cells or L-type Ca2+ currents. Reducing extracellular Cl- to 10 mM shifted ESTICs to positive potentials as predicted by the Nernst equation. The relatively rapid shift in ESTICs when NKCC1 was blocked suggests that significant changes in the transmembrane Cl- gradient occur during the slow-wave cycle, possibly within microdomains formed between endoplasmic reticulum and the plasma membrane in ICC. Recovery of Cl- via NKCC1 might have additional consequences on shaping the waveforms of slow waves via Na+ entry into microdomains.

Intracellular Ca(2+) release from endoplasmic reticulum regulates slow wave currents and pacemaker activity of interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) provide pacemaker activity in gastrointestinal muscles that underlies segmental and peristaltic contractions. ICC generate electrical slow waves that are due to large-amplitude inward currents resulting from anoctamin 1 (ANO1) channels, which are Ca(2+)-activated Cl(-) channels. We investigated the hypothesis that the Ca(2+) responsible for the stochastic activation of ANO1 channels during spontaneous transient inward currents (STICs) and synchronized activation of ANO1 channels during slow wave currents comes from intracellular Ca(2+) stores. ICC, obtained from the small intestine of Kit(+/copGFP) mice, were studied under voltage and current clamp to determine the effects of blocking Ca(2+) uptake into stores and release of Ca(2+) via inositol 1,4,5-trisphosphate (IP3)-dependent and ryanodine-sensitive channels. Cyclocpiazonic acid, thapsigargin, 2-APB, and xestospongin C inhibited STICs and slow wave currents. Ryanodine and tetracaine also inhibited STICs and slow wave currents. Store-active compounds had no direct effects on ANO1 channels expressed in human embryonic kidney-293 cells. Under current clamp, store-active drugs caused significant depolarization of ICC and reduced spontaneous transient depolarizations (STDs). After block of ryanodine receptors with ryanodine and tetracaine, repolarization did not restore STDs. ANO1 expressed in ICC has limited access to cytoplasmic Ca(2+) concentration, suggesting that pacemaker activity depends on Ca(2+) dynamics in restricted microdomains. Our data from studies of isolated ICC differ somewhat from studies on intact muscles and suggest that release of Ca(2+) from both IP3 and ryanodine receptors is important in generating pacemaker activity in ICC.

Myopia among children and adolescents: an epidemiological study in Fuzhou City.

Objective: To provide a reference for the prevention and control of myopia by analyzing and discussing the findings of an epidemiological survey of the prevalence of myopia among children and adolescents in Fuzhou City from 2019 to 2021. Methods: Participants for this cross-sectional study were drawn from Gulou District and Minqing County in Fuzhou City using cluster random sampling to account for differences in population density, economic development, and other environmental variables. Results: Myopia was more prevalent in 2020 than in 2019, but by 2021 it had dropped to about the same level as in 2019. Myopia was more prevalent among girls than boys during the course of the study period, with a three-year prevalence of 44.72% for boys and 52.16% for girls. Mild myopia accounted for 24.14% of all cases, followed by moderate myopia at 19.62%, and severe myopia at 4.58%. Students in urban regions had a prevalence of myopia equivalent to that of students in the suburbs, and this prevalence rose with age. Conclusion: Myopia was quite prevalent among children and adolescents in Fuzhou City, and was shown to be steadily rising as students progressed through the school system. This suggests that all levels of government, educational institutions, medical facilities, and concerned parents in Fujian Province should focus on the issue of myopia and collaborate to reduce the risk factors for the development of myopia in school-aged participants.

Anoctamins and gastrointestinal smooth muscle excitability.

Interstitial cells of Cajal (ICC) generate electrical pacemaker activity in gastrointestinal smooth muscles. We investigated whether Tmem16a, which encodes anoctamin 1 (ANO1), a Ca(2+)-activated Cl(-) channel, might be involved in pacemaker activity in ICC. The Tmem16a transcripts and ANO1 were expressed robustly in GI muscles, specifically in ICC in murine, non-human primate (Macaca fascicularis) and human GI tracts. Splice variants of Tmem16a, as well as other paralogues of the Tmem16 family, were expressed in gastrointestinal muscles. Calcium-activated Cl(-) channel blocking drugs, niflumic acid and DIDS blocked slow waves in intact muscles of mouse, primate and human small intestine and stomach. Slow waves failed to develop in Tmem16a knock-out mice (Tmem16a(tm1Bdh/tm1Bdh)). The pacemaker mechanism was investigated in isolated ICC from transgenic mice with constitutive expression of copepod super green fluorescent protein (copGFP). Depolarization of ICC activated inward currents due to a Cl(-)-selective conductance. Removal of extracellular Ca(2+), replacement of Ca(2+) with Ba(2+), or extracellular Ni(2+) (30 µM) blocked the inward current. Single Ca(2+)-activated Cl(-) channels with a unitary conductance of 7.8 pS were resolved in excised patches from ICC. The inward current was blocked in a concentration-dependent manner by niflumic acid (IC(50) = 4.8 µM). The role of ANO1 in cholinergic responses in ICC was also investigated. Carbachol activated Ca(2+)-activated Cl(-) currents in ICC, and responses to cholinergic nerve stimulation were blocked by niflumic acid in intact muscles. Anoctamin 1 is a prominent conductance in ICC, and these channels appear to be involved in pacemaker activity and in responses to enteric excitatory neurotransmitters.

Evoked Cortical Depolarizations Before and After the Amyloid Plaque Accumulation: Voltage Imaging Study.

BACKGROUND: In Alzheimer's disease (AD), synaptic dysfunction is thought to occur many years before the onset of cognitive decline. OBJECTIVE: Detecting synaptic dysfunctions at the earliest stage of AD would be desirable in both clinic and research settings. METHODS: Population voltage imaging allows monitoring of synaptic depolarizations, to which calcium imaging is relatively blind. We developed an AD mouse model (APPswe/PS1dE9 background) expressing a genetically-encoded voltage indicator (GEVI) in the neocortex. GEVI was restricted to the excitatory pyramidal neurons (unlike the voltage-sensitive dyes). RESULTS: Expression of GEVI did not disrupt AD model formation of amyloid plaques. GEVI expression was stable in both AD model mice and Control (healthy) littermates (CTRL) over 247 days postnatal. Brain slices were stimulated in layer 2/3. From the evoked voltage waveforms, we extracted several parameters for comparison AD versus CTRL. Some parameters (e.g., temporal summation, refractoriness, and peak latency) were weak predictors, while other parameters (e.g., signal amplitude, attenuation with distance, and duration (half-width) of the evoked transients) were stronger predictors of the AD condition. Around postnatal age 150 days (P150) and especially at P200, synaptically-evoked voltage signals in brain slices were weaker in the AD groups versus the age- and sex-matched CTRL groups, suggesting an AD-mediated synaptic weakening that coincides with the accumulation of plaques. However, at the youngest ages examined, P40 and P80, the AD groups showed differentially stronger signals, suggesting "hyperexcitability" prior to the formation of plaques. CONCLUSION: Our results indicate bidirectional alterations in cortical physiology in AD model mice; occurring both prior (P40-80), and after (P150-200) the amyloid deposition.

Muscarinic activation of Ca2+-activated Cl- current in interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) provide pacemaker activity and functional bridges between enteric motor nerve terminals and gastrointestinal smooth muscle cells. The ionic conductance(s) in ICC that are activated by excitatory neural inputs are unknown. Transgenic mice (Kit(copGFP/+)) with constitutive expression of a bright green fluorescent protein were used to investigate cellular responses of ICC to cholinergic stimulation. ICC displayed spontaneous transient inward currents (STICs) under voltage clamp that corresponded to spontaneous transient depolarizations (STDs) under current clamp. STICs reversed at 0 mV when E(Cl) = 0 mV and at -40 mV when E(Cl) was -40 mV, suggesting the STICs were due to a chloride conductance. Carbachol (CCh, 100 nm and 1 µm) induced a sustained inward current (depolarization in current clamp) and increased the amplitude and frequency of STICs and STDs. CCh responses were blocked by atropine (10 µm) or 4-DAMP (100 nm), an M(3) receptor antagonist. STDs were blocked by niflumic acid and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (both 100 µm), and CCh had no effect in the presence of these drugs. The responses of intact circular muscles to CCh and stimulation of intrinsic excitatory nerves by electrical field stimulation (EFS) were also compared. CCh (1 µm) caused atropine-sensitive depolarization and increased the maximum depolarization of slow waves. Similar atropine-sensitive responses were elicited by stimulation of intrinsic excitatory neurons. Niflumic acid (100 µm) blocked responses to EFS but had minor effect on responses to exogenous CCh. These data suggest that different ionic conductances are responsible for electrical responses elicited by bath-applied CCh and cholinergic nerve stimulation.

Studying Synaptically Evoked Cortical Responses ex vivo With Combination of a Single Neuron Recording (Whole-Cell) and Population Voltage Imaging (Genetically Encoded Voltage Indicator).

In a typical electrophysiology experiment, synaptic stimulus is delivered in a cortical layer (1-6) and neuronal responses are recorded intracellularly in individual neurons. We recreated this standard electrophysiological paradigm in brain slices of mice expressing genetically encoded voltage indicators (GEVIs). This allowed us to monitor membrane voltages in the target pyramidal neurons (whole-cell), and population voltages in the surrounding neuropil (optical imaging), simultaneously. Pyramidal neurons have complex dendritic trees that span multiple cortical layers. GEVI imaging revealed areas of the brain slice that experienced the strongest depolarization on a specific synaptic stimulus (location and intensity), thus identifying cortical layers that contribute the most afferent activity to the recorded somatic voltage waveform. By combining whole-cell with GEVI imaging, we obtained a crude distribution of activated synaptic afferents in respect to the dendritic tree of a pyramidal cell. Synaptically evoked voltage waves propagating through the cortical neuropil (dendrites and axons) were not static but rather they changed on a millisecond scale. Voltage imaging can identify areas of brain slices in which the neuropil was in a sustained depolarization (plateau), long after the stimulus onset. Upon a barrage of synaptic inputs, a cortical pyramidal neuron experiences: (a) weak temporal summation of evoked voltage transients (EPSPs); and (b) afterhyperpolarization (intracellular recording), which are not represented in the GEVI population imaging signal (optical signal). To explain these findings [(a) and (b)], we used four voltage indicators (ArcLightD, chi-VSFP, Archon1, and di-4-ANEPPS) with different optical sensitivity, optical response speed, labeling strategy, and a target neuron type. All four imaging methods were used in an identical experimental paradigm: layer 1 (L1) synaptic stimulation, to allow direct comparisons. The population voltage signal showed paired-pulse facilitation, caused in part by additional recruitment of new neurons and dendrites. "Synaptic stimulation" delivered in L1 depolarizes almost an entire cortical column to some degree.

Population imaging discrepancies between a genetically-encoded calcium indicator (GECI) versus a genetically-encoded voltage indicator (GEVI).

Genetically-encoded calcium indicators (GECIs) are essential for studying brain function, while voltage indicators (GEVIs) are slowly permeating neuroscience. Fundamentally, GECI and GEVI measure different things, but both are advertised as reporters of "neuronal activity". We quantified the similarities and differences between calcium and voltage imaging modalities, in the context of population activity (without single-cell resolution) in brain slices. GECI optical signals showed 8-20 times better SNR than GEVI signals, but GECI signals attenuated more with distance from the stimulation site. We show the exact temporal discrepancy between calcium and voltage imaging modalities, and discuss the misleading aspects of GECI imaging. For example, population voltage signals already repolarized to the baseline (~ disappeared), while the GECI signals were still near maximum. The region-to-region propagation latencies, easily captured by GEVI imaging, are blurred in GECI imaging. Temporal summation of GECI signals is highly exaggerated, causing uniform voltage events produced by neuronal populations to appear with highly variable amplitudes in GECI population traces. Relative signal amplitudes in GECI recordings are thus misleading. In simultaneous recordings from multiple sites, the compound EPSP signals in cortical neuropil (population signals) are less distorted by GEVIs than by GECIs.

In Vitro Testing of Voltage Indicators: Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, BeRST1, FlicR1, and Chi-VSFP-Butterfly.

Genetically encoded voltage indicators (GEVIs) could potentially be used for mapping neural circuits at the plane of synaptic potentials and plateau potentials-two blind spots of GCaMP-based imaging. In the last year alone, several laboratories reported significant breakthroughs in the quality of GEVIs and the efficacy of the voltage imaging equipment. One major obstacle of using well performing GEVIs in the pursuit of interesting biological data is the process of transferring GEVIs between laboratories, as their reported qualities (e.g., membrane targeting, brightness, sensitivity, optical signal quality) are often difficult to reproduce outside of the laboratory of the GEVI origin. We have tested eight available GEVIs (Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, FlicR1, and chi-VSFP-Butterfly) and two voltage-sensitive dyes (BeRST1 and di-4-ANEPPS). We used the same microscope, lens, and optical detector, while the light sources were interchanged. GEVI voltage imaging was attempted in the following three preparations: (1) cultured neurons, (2) HEK293 cells, and (3) mouse brain slices. Systematic measurements were successful only in HEK293 cells and brain slices. Despite the significant differences in brightness and dynamic response (ON rate), all tested indicators produced reasonable optical signals in brain slices and solid in vitro quality properties, in the range initially reported by the creator laboratories. Side-by-side comparisons between GEVIs and organic dyes obtained in HEK293 cells and brain slices by a "third party" (current data) will be useful for determining the right voltage indicator for a given research application.

Visual feedback therapy for restoration of upper limb function of stroke patients.

OBJECTIVE: To investigate the effects of mirror neuron theory-based visual feedback therapy (VFT) on restoration of upper limb function of stroke patients and motor-related cortical function using functional magnetic resonance imaging (fMRI). METHODS: Hemiplegic stroke patients were randomly divided into two groups: a VFT group and a control (CTL) group. Sixteen patients in the VFT group received conventional rehabilitation (CR) and VFT for 8 weeks, while 15 patients in the CTL group received only CR. The Barthel Index (BI) was used to assess the activities of daily living at baseline and the 8th week of the recovery training period. The Fugl-Meyer assessment (FMA) scale, somatosensory evoked potential (SEP), and fMRI were used to evaluate the recovery effect of the training therapies. The latencies and amplitudes of N9 and N20 were measured. Before recovery training, fMRI was performed for all patients in the VFT and CTL groups. In addition, 17 patients (9 in the VFT group and 8 in the CTL group) underwent fMRI for follow-up 2 months after treatment. Qualitative data were analyzed using the χ 2 test. The independent sample t-test was used to compare normally distributed data among different groups, the paired sample t-test was used to compare data between groups, and the non-parametric test was used to comparing data without normal distribution among groups. RESULTS: There were no significant differences between the VFT and CTL group in all indexes. However, after 8 weeks of recovery training, these indexes were all significantly improved (P < 0.05). As compared with the CTL group, the FMA scores, BI, and N9/N20 latencies and amplitudes of SEP in the VFT group were significantly improved (P < 0.05). Two months after recovery training, fMRI showed that the degree of activation of the bilateral central anterior gyrus, parietal lobe, and auxiliary motor areas was significantly higher in the VFT group than the CTL group (P < 0.05). CONCLUSIONS: VFT based on mirror neuron theory is an effective approach to improve upper extremity motor function and daily activity performance of stroke patients. The therapeutic mechanism promotes motor relearning by activating the mirror neuron system and motor cortex. SEP amplitudes increased only for patients who participated in visual feedback. VFT promotes sensory-motor plasticity and behavioral changes in both the motor and sensory domains.

Corrigendum: Na+/Ca2+ Exchange and Pacemaker Activity of Interstitial Cells of Cajal.

[This corrects the article DOI: 10.3389/fphys.2020.00230.].

Na+/Ca2 + Exchange and Pacemaker Activity of Interstitial Cells of Cajal.

Interstitial cells of Cajal (ICC) are pacemaker cells that generate electrical slow waves in gastrointestinal (GI) smooth muscles. Slow waves organize basic motor patterns, such as peristalsis and segmentation in the GI tract. Slow waves depend upon activation of Ca2+-activated Cl- channels (CaCC) encoded by Ano1. Slow waves consist of an upstroke depolarization and a sustained plateau potential that is the main factor leading to excitation-contraction coupling. The plateau phase can last for seconds in some regions of the GI tract. How elevated Ca2+ is maintained throughout the duration of slow waves, which is necessary for sustained activation of CaCC, is unknown. Modeling has suggested a role for Na+/Ca2+ exchanger (NCX) in regulating CaCC currents in ICC, so we tested this idea on murine intestinal ICC. ICC of small and large intestine express NCX isoforms. NCX3 is closely associated with ANO1 in ICC, as shown by immunoprecipitation and proximity ligation assays (PLA). KB-R7943, an inhibitor of NCX, increased CaCC current in ICC, suggesting that NCX, acting in Ca2+ exit mode, helps to regulate basal [Ca2+] i in these cells. Shifting NCX into Ca2+ entry mode by replacing extracellular Na+ with Li+ increased spontaneous transient inward currents (STICs), due to activation of CaCC. Stepping ICC from -80 to -40 mV activated slow wave currents that were reduced in amplitude and duration by NCX inhibitors, KB-R7943 and SN-6, and enhanced by increasing the NCX driving force. SN-6 reduced the duration of clustered Ca2+ transients that underlie the activation of CaCC and the plateau phase of slow waves. Our results suggest that NCX participates in slow waves as modeling has predicted. Dynamic changes in membrane potential and ionic gradients during slow waves appear to flip the directionality of NCX, facilitating removal of Ca2+ during the inter-slow wave interval and providing Ca2+ for sustained activation of ANO1 during the slow wave plateau phase.

A Ca(2+)-activated Cl(-) conductance in interstitial cells of Cajal linked to slow wave currents and pacemaker activity.

Interstitial cells of Cajal (ICC) are unique cells that generate electrical pacemaker activity in gastrointestinal (GI) muscles. Many previous studies have attempted to characterize the conductances responsible for pacemaker current and slow waves in the GI tract, but the precise mechanism of electrical rhythmicity is still debated. We used a new transgenic mouse with a bright green fluorescent protein (copGFP) constitutively expressed in ICC to facilitate study of these cells in mixed cell dispersions. We found that ICC express a specialized 'slow wave' current. Reversal of tail current analysis showed this current was due to a Cl(-) selective conductance. ICC express ANO1, a Ca(2+)-activated Cl(-) channel. Slow wave currents are not voltage dependent, but a secondary voltage-dependent process underlies activation of these currents. Removal of extracellular Ca(2+), replacement of Ca(2+) with Ba(2+), or extracellular Ni(2+) (30 microm) blocked the slow wave current. Single Ca(2+)-activated Cl() channels with a unitary conductance of 7.8 pS were resolved in excised patches of ICC. These are similar in conductance to ANO1 channels (8 pS) expressed in HEK293 cells. Slow wave current was blocked in a concentration-dependent manner by niflumic acid (IC(50) = 4.8 microm). Slow wave currents are associated with transient depolarizations of ICC in current clamp, and these events were blocked by niflumic acid. These findings demonstrate a role for a Ca(2+)-activated Cl(-) conductance in slow wave current in ICC and are consistent with the idea that ANO1 participates in pacemaker activity.

Direct activation of transient receptor potential vanilloid 1(TRPV1) by diacylglycerol (DAG).

The capsaicin receptor, known as transient receptor potential channel vanilloid subtype 1 (TRPV1), is activated by a wide range of noxious stimulants and putative ligands such as capsaicin, heat, pH, anandamide, and phosphorylation by protein kinase C (PKC). However, the identity of endogenous activators for TRPV1 under physiological condition is still debated. Here, we report that diacylglycerol (DAG) directly activates TRPV1 channel in a membrane-delimited manner in rat dorsal root ganglion (DRG) neurons. 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane-permeable DAG analog, elicited intracellular Ca2+ transients, cationic currents and cobalt uptake that were blocked by TRPV1-selective antagonists, but not by inhibitors of PKC and DAG lipase in rat DRG neurons or HEK 293 cells heterologously expressing TRPV1. OAG induced responses were about one fifth of capsaicin induced signals, suggesting that OAG displays partial agonism. We also found that endogenously produced DAG can activate rat TRPV1 channels. Mutagenesis of rat TRPV1 revealed that DAG-binding site is at Y511, the same site for capsaicin binding, and PtdIns(4,5)P2binding site may not be critical for the activation of rat TRPV1 by DAG in heterologous system. We propose that DAG serves as an endogenous ligand for rat TRPV1, acting as an integrator of Gq/11-coupled receptors and receptor tyrosine kinases that are linked to phospholipase C.

Developmental characteristics and response to iron toxicity of root border cells in rice seedlings.

To investigate the Fe2+ effects on root tips in rice plant, experiments were carried out using border cells in vitro. The border cells were pre-planted in aeroponic culture and detached from root tips. Most border cells have a long elliptical shape. The number and the viability of border cells in situ reached the maxima of 1600 and 97.5%, respectively, at 20-25 mm root length. This mortality was more pronounced at the first 1-12 h exposure to 250 mg/L Fe2+ than at the last 12-36 h. After 36 h, the cell viability exposed to 250 mg/L Fe2+ decreased to nought, whereas it was 46.5% at 0 mg/L Fe2+. Increased Fe2+ dosage stimulated the death of detached border cells from rice cultivars. After 4 h Fe2+ treatment, the cell viabilities were > or =80% at 0 and 50 mg/L Fe2+ treatment and were <62% at 150, 250 and 350 mg/L Fe2+ treatment; The viability of border cells decreased by 10% when the Fe2+ concentration increased by 100 mg/L. After 24 h Fe2+ treatment, the viabilities of border cells at all the Fe2+ levels were <65%; The viability of border cells decreased by 20% when the Fe2+ concentration increased by 100 mg/L. The decreased viabilities of border cells indicated that Fe2+ dosage and treatment time would cause deadly effect on the border cells. The increased cell death could protect the root tips from toxic harm. Therefore, it may protect root from the damage caused by harmful iron toxicity.

Acquisition of in vitro and in vivo functionality of Nurr1-induced dopamine neurons.

Neural precursor cells provide an expandable source of neurons and glia for basic and translational applications. However, little progress has been made in directing naive neural precursors toward specific neuronal fates such as midbrain dopamine (DA) neurons. We have recently demonstrated that transgenic expression of the nuclear orphan receptor Nurr1 is sufficient to drive dopaminergic differentiation of forebrain embryonic rat neural precursors in vitro. However, Nurr1-induced DA neurons exhibit immature neuronal morphologies and functional properties and are unable to induce behavioral recovery in rodent models of Parkinson's disease (PD). Here, we report on the identification of key genetic factors that drive morphological and functional differentiation of Nurr1-derived DA neurons. We show that coexpression of Nurr1, Bcl-XL, and Sonic hedgehog (SHH) or Nurr1 and the proneural bHLH factor Mash1 is sufficient to drive naive rat forebrain precursors into neurons exhibiting the biochemical, electrophysiological, and functional properties of DA neuron in vitro. On transplantation into the striatum of Parkinsonian rats, precursor cells engineered with Nurr1/SHH/Bcl-XL or Nurr1/Mash1 survived in vivo and differentiated into mature DA neurons that can reverse the behavioral deficits in the grafted animals.

[Relationship between children's motor coordination and their physical growth].

OBJECTIVE: To explore the relationship between children's motor coordination and their physical growth to provide clues for clarifying the causal relationship between them and to effectively enhance the children's physical growth. METHOD: Ten kindergartens were selected randomly from district of Hongkou, Putuo and Pudong in Shanghai, and 1099 children were included in the analysis. The children's motor coordination was assessed using Developmental Coordination Disorder Questionnaire (DCDQ). The relationship between the children's motor coordination and their physical growth were analyzed by Structural Equation Model (SEM). The above relationship by different gender, age and BMI (overweight or not) were analyzed with multi-group SEM. RESULTS: Of 1099 subjects, 561 were boys (51%), and 538 were girls (49%). Of the total subjects, 354 (32.2%) were children aged 3-years old, 441 (40.1%) were children aged 4-years, 276 (25.2%) were children aged 5-years, and 28 were children (2.5%) aged 6-years old. The result of SEM showed that the children's gross motor, fine motor and general motor ability was correlated positively with children's physical growth (P < 0.001), their standardized estimation of structural coefficient were 0.40, 0.36, 0.37 respectively. The result of multi-group SEM showed that there was no significant difference in the SEM between different gender and ages. The fine motor ability was positively correlated with child physical growth (P < 0.001). There was no inter-group difference in the structural model (each P > 0.05). However, there was difference in the structural model between overweight and normal group, of them, only the structural coefficient of gross motor and physical growth were different between the two groups (t = 1.697, P < 0.05). CONCLUSION: There is a relationship between children's motor coordination and physical growth. The degree of association between the gross moter and physical growth in overweight children were different from the normal children. Further study on the factors influencing the children's physical growth is needed.

[Associations of human leukocyte antigen-A, B, DRB1 genes with leukemia patients in Anhui province of China].

This study was aimed to investigate the relation of human leukocyte antigen-A, B, DRB1 genes with the susceptibility of population to leukemia in Anhui province of China. The HLA genotypes were analyzed by PCR-SSP in 140 patients with chronic myelocytic leukemia (CML), 84 patients with acute lymphoblastic leukemia (ALL), 90 patients with acute nonlymphocytic leukemia (ANLL) and 916 healthy unrelated donors of hematopoietic stem cell as normal control admitted to Anhui provincial hospital. The gene frequencies of HLA-A, B, DRB1 between patients and normal controls were compared, chi² test was used for statistical analysis. The results showed that as compared with normal controls, the gene frequencies of A2, A11, B58 and DR9 in CML patients all obviously increased, and gene frequency of DR7 decreased; the gene frequencies of All and B13 in ALL patients were significantly higher than that in normal controls; the gene frequencies of A24, B58 and DR9 in ANLL patients were significantly higher than that in normal controls. It is concluded that HLA-A2, A11, B58 and DR9 are predisposing genes of CML patients, DR7 is an antagonistic gene, HLA-A11 and B13 are predisposing genes of ALL patients, HLA-A24, B58 and DR9 are predisposing genes of ANLL patients.

Desensitization of canonical transient receptor potential channel 5 by protein kinase C.

The classic type of transient receptor potential channel (TRPC) is a molecular candidate for Ca(2+)-permeable cation channel in mammalian cells. TRPC5 is desensitized rapidly after activation by G protein-coupled receptor. Herein we report our investigation into the desensitization of mTRPC5 and localization of the molecular determinants of this desensitization using mutagenesis. TRPC5 was initially activated by muscarinic stimulation using 100 microM carbachol (CCh) and then decayed rapidly even in the presence of CCh (desensitization). Increased EGTA or omission of MgATP in the pipette solution slowed the rate of this desensitization. The protein kinase C (PKC) inhibitors, 1 microM chelerythrine, 100 nM GF109203X, or PKC peptide inhibitor (19-36), inhibited this desensitization of TRPC5 activated by 100 microM CCh. When TRPC5 current was activated by intracellular GTPgammaS, PKC inhibitors prevented TRPC5 desensitization and the mutation of TRPC5 T972 to alanine slowed the desensitization process dramatically. We conclude that the desensitization of TRPC5 occurs via PKC phosphorylation and suggest that threonine at residue 972 of mouse TRPC5 might be required for its phosphorylation by PKC.