Semi-implantable device based on multiplexed microfilament electrode cluster for continuous monitoring of physiological ions

Modern medicine is increasingly interested in advanced sensors to detect and analyze biochemical indicators.Ion sensors based on potentiometric methods are a promising platform for monitoring physiological ions in biological subjects.Current semi-implantable devices are mainly based on single-parameter detection.Miniaturized semi-implantable electrodes for multiparameter sensing have more restrictions on the electrode size due to biocompatibility considerations,but reducing the electrode surface area could potentially limit electrode sensitivity.This study developed a semi-implantable device system comprising a multiplexed microfilament electrode cluster(MMEC)and a printed circuit board for real-time monitoring of intra-tissue K^(+),Ca^(2+),and Na^(+)concentrations.The electrode surface area was less important for the potentiometric sensing mechanism,suggesting the feasibility of using a tiny fiber-like electrode for potentiometric sensing.The MMEC device exhibited a broad linear response(K^(+):2–32 mmol/L;Ca^(2+):0.5–4 mmol/L;Na^(+):10–160 mmol/L),high sensitivity(about 20–45 mV/decade),temporal stability(>2weeks),and good selectivity(>80%)for the above ions.In vitro detection and in vivo subcutaneous and brain experiment results showed that the MMEC system exhibits good multi-ion monitoring performance in several complex environments.This work provides a platform for the continuous real-time monitoring of ion fluctuations in different situations and has implications for developing smart sensors to monitor human health.

Preparation of Silk-Like PET Microfilament and Its Properties

The polyester microfilament was prepared by means ofnormal fully drawn yarn(FDY)equipment.The effectof water content in chips,the molecular weight of thechips,the jet stretch ratio and the lateral blow on thespinnability and the finest titre of filament that could bereach were discussed.Under convenient conditions,thefiber with linear density of about 1.4 dtex could be ob-tained.By means of wide angle X-ray diffractometer(WAXD),differential scanning calorimeter(DSC)andInstrontester,the structure and properties of the mi-crofilament were discussed.

The Distribution and Morphology Alterations of Microfilaments and Microtubules in Mesophyll Cells and Root-Tip Cells of Wheat Seedlings under Enhanced Ultraviolet-B Radiation

The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-1), were examined through the confocal laser scanning microscope (Model FV1000, Olympus, Japan). Microtubule was labeled with an indirect immunofluorescence staining method, and microfilament was labeled with fluorescein isothiocyanate-phalloidin (FITC-Ph) as probes. The results indicated that microtubules in mesophyll cells, compared with the controls, would be depolymerized significantly, and dispersed randomly showing some spots or short rods in the cytoplasm, under the enhanced UV-B radiation condition. The microtubule bundles tended to be diffused, and the fluorescence intensity of that significantly decreased. The distribution pattern of microfilaments, which usually arranged parallelly in control cells, was broken up by enhanced UV-B radiation. We further investigated the distribution and morphology of microtubules in root-tip cells during every stage of cell division, and found that these aberrant phenomena of microtubules were often associated with abnormal cell division. Our findings suggested that the distribution, morphology and structure of cytoskeleton in mesophyll cells and root-tip cells of wheat seedlings would be affected by enhanced UV-B radiation, which might be related to abnormal cell division caused by enhanced UV-B radiation as an extracellular signal.

The alkaline tolerance in Arabidopsis requires stabilizing microfilament partially through inactivation of PKS5 kinase

High soil pH is harmful to plant growth and development. The organization and dynamics of microfilament （MF） cytoskeleton play important roles in the plant anti-alkaline process. In the previous study, we determined that alkaline stress induces a signal that triggers MF dynamicsdependent root growth. In this study we identified that PKS5 kinase involves in this regulatory process to facilitate the signal to reach the downstream target ME Under pH 8.3 treatment, the depolymerization of MF was faster in pks5-4 （PKS5 kinase constitutively activated） than that in wild-type plants. The inhibition of wild-type, pks5-1, and pks5-4 root growth by pH 8.3 was correlated to their MF depolymerization rate. When the plants were treated with phalloidin to stabilize MF, the high pH sensitive phenotype of pks5-4 can be partially rescued. When the plants were treated with a kinase inhibitor Staurosporine, the MF depolymerization rate in pks5-4 was similar as that in wild-type under pH 8.3 treatment and the sensitivity of root growth was also rescued. However, when the plants were treated with LaC13, a calcium channel blocker, the root growth sensitivity ofpks5-4 under pH 8.3 was rescued but MF depolymerization was even faster than that of plants without LaC13 treatment. These results suggest that the PKS5 involves in external high pH signal mediated MF depolymerization, and that may be independent of calcium signal.

Effects of Microfilamentous Reorganization on DG-PKC Pathway

Breakdown of phosphotidylinositol-4, 5-bisphosphate （PIP2） activates two distinct signal systems:production of inositol-1, 4, 5-trisphosphate （IP3） triggers release of calcium from intracellular stores, and release of diacylglycerol （DG） activates

The effects of microfilament and microtubule inhibitors and periodic electrical impulses on phloem transport in pea seedling

In phloem transport, whether protoplasmic activity participates in assisting sap flow in sieve element_companion cell complex has long been in debate. The present investigation assumed microfilament (MF) and microtubule (MT), the two constituents of the protoplasmic cytoskeleton, as motive force, and employed germinating pea seedling suspended in moist chamber as experimental material: the seed being the source; the elongating root, the sink. 14 C_labeled sucrose was added to the seed as indicator. The amount of sap transported from source to sink was measured by the increase in root elongation. The transport phloem was within the cylinder of the peeled root in the middle. The exposed cylinder was treated with MF inhibitor (cytochalasin B), or microtubule inhibitor (amiphos_methyl). Results showed that the sap influx into the elongating root, and the 14 C activity as well, was reduced by about one half in treatment with cytochalasin B, and much less by amiphos_methyl treatment. Similar effect was shown in electrical impulse treatment, which seems to disrupt the MF and MT configuration.

Application of VIGS system to explore the function of common wheat TaADF7

As an allohexaploid plant,common wheat has a complex gene structure,making it difficult to study its gene function.Virus-induced gene silencing(VIGS)is an important tool for the rapid analysis of plant gene function.In this study,the gene silencing system,namely,barley stripe mosaic virus(BSMV)-VIGS induced by BSMV was used to silence the wheat phytoene desaturase(TaPDS)and actin depolymerization factor(TaADF7)genes and determine the effect of gene silencing on wheat.TaPDS was used as an indicator gene to determine the feasibility of VIGS system,while TaADF7 was used as a test gene to determine its effect on wheat growth.Results showed that the leaves of tobacco and wheat were bleached by the mixture of pCaBS-α,pCaBS-β,and pCaBS-γ::TaPDS,indicating that the TaPDS gene was silenced,and the bleached leaves had physiological activity as determined by trypan blue staining.Therefore,the VIGS system was efficient and available.After the tobacco was treated with pCaBS-α,pCaBS-β,and pCaBS-γ::TaADF7,the viral suspension was obtained.The expression of TaADF7 gene was downregulated after wheat leaves were infected by friction,indicating that the expression of TaADF7 was silenced.Laser confocal scanning microscopy showed that the silencing of TaADF7 enhanced the fluorescence of microfilament skeleton in mesophyll protoplasts and significantly reduced the plant height.Results showed that TaADF7 affected cell division and plant growth by inhibiting microfilament depolymerization.In conclusion,the BSMV-VIGS system was used to silence wheat TaPDS and TaADF7 genes.Bleaching phenomenon was observed in wheat leaves after TaPDS silencing.After TaADF7 silencing,microfilaments in wheat mesophyll cells gathered into coarse bundles,which affected the dynamics of microfilaments and inhibited plant growth.

Dancing to a somewhat different rhythm: Cell migration along thenatural basement membrane

Much of our understanding of the events which underlie cell migration has been derived from studies of cells intissue culture. One of the components that mediates this process is the dynamic actin-based microfilament system that canreorganize itself into so-called stress fibers that are considered essential components for cell motility. In contrast, relativelyfew studies have investigated cell movement along an extracellular matrix (ECM) which is known to influence both cellularorganization and behavior. This opinion/viewpoint article briefly reviews cell migration during corneal endothelial woundrepair along the tissue’s natural basement membrane, Descemet’s membrane. Because the tissue exists as a cell monolayer itaffords one an opportunity to readily explore the effect of cell/matrix influences on cell motility. As such, cell movementalong this substrate differs somewhat from that found in vitro and migrating endothelial cells also demonstrate an abilityto move along the ECM without the benefit of having an organized actin cytoskeleton.

Role of Calcium in Glucagon Secretion

The role of calcium ions in the process by which nutrients affect glucagon secretion by pancreatic islet α-cells remains the matter of an apparently endless debate. In the prolongation of recent articles dealing with this matter, the present review draws attention to the dual role of Ca2+ as revealed by prior publications. In such a perspective, emphasis is placed on the increase in glucagon output in response to the omission of extracellular Ca2+ as recorded in the presence of D-glucose or 2-ketoisocaproate, the permissive role of extracellular Ca2+ in the positive secretory response to arginine or a mixture of fumarate, glutamate and pyruvate, and the effects of an organic calcium-antagonist on glucagon output. Considering the role currently ascribed to Ca2+ in the activation of motile events involved in stimulus-secretion coupling, attention is also given to the effects of cytochalasin B, D2O and mitotic-spindle inhibitors upon the secretory response of α-cells exposed to D-glucose in the absence or presence of arginine.

嗜热四膜虫接合生殖后期皮层细胞骨架蛋白的研究(英文)

用秋水仙素和细胞松弛素B处理接合期的嗜热四膜虫 ,以观察其对接合生殖期 ,尤其是接合后期的嗜热四膜虫皮层细胞骨架蛋白的影响。用秋水仙素处理的试验组的皮层细胞骨架蛋白组分中 34KD、37KD、46KD和 5 7KD蛋白的含量有明显改变 ,而用细胞松弛素B处理的试验组中 40KD和 74KD蛋白的含量改变较大。根据相关文献 ,作者推测 34KD、37KD、46KD、5 7KD蛋白是微管蛋白 ,而 40KD和 74KD可能是微丝蛋白。这些蛋白对嗜热四膜虫接合过程中的形态发生的重要作用有待进一步研究。

SCAB1 coordinates sequential Ca^(2+) and ABA signals during osmotic stress induced stomatal closure in Arabidopsis

Hyperosmotic stress caused by drought is a detrimental threat to plant growth and agricultural productivity due to limited water availability.Stomata are gateways of transpiration and gas exchange,the swift adjustment of stomatal aperture has a strong influence on plant drought resistance.Despite intensive investigations of stomatal closure during drought stress in past decades,little is known about how sequential signals are integrated during complete processes.Here,we discovered that the rapid Ca^(2+) signaling and subsequent abscisic acid(ABA)signaling contribute to the kinetics of both F-actin reorganizations and stomatal closure in Arabidopsis thaliana,while STOMATAL CLOSURE-RELATED ACTIN BINDING PROTEIN1(SCAB1)is the molecular switch for this entire process.During the early stage of osmotic shock responses,swift elevated calcium signaling promotes SCAB1 phosphorylation through calcium sensors CALCIUM DEPENDENT PROTEIN KINASE3(CPK3)and CPK6.The phosphorylation restrained the microfilament binding affinity of SCAB1,which bring about the Factin disassembly and stomatal closure initiation.As the osmotic stress signal continued,both the kinase activity of CPK3 and the phosphorylation level of SCAB1 attenuated significantly.We further found that ABA signaling is indispensable for these attenuations,which presumably contributed to the actin filament reassembly process as well as completion of stomatal closure.Notably,the dynamic changes of SCAB1 phosphorylation status are crucial for the kinetics of stomatal closure.Taken together,our results support a model in which SCAB1 works as a molecular switch,and directs the microfilament rearrangement through integrating the sequentially generated Ca^(2+) and ABA signals during osmotic stress induced stomatal closure.

Nanomechanical vibration profiling of oocytes

The beginning of a mammalian life commences with a fertilized oocyte.The study of oocytes is certainly one of the most intriguing scientific questions of our time.Herein,we studied oocytes from a mechanical perspective and characterized the typical life activities of oocytes by nanomechanical vibrations.During the development of oocytes from the germinal vesicle(GV)stage to the zygotes,the GV stage oocytes induced a significant nanomechanical vibration,compared with the oocytes in meiosis I(MI)and meiosis II(MII)stages and zygotes.We analyzed the characteristics of mechanical vibrations of oocytes,including the amplitude as well as the frequency.It showed that the amplitude and frequency of nanomechanical vibrations induced by oocytes were caused by the cytoskeleton(microfilaments)and the distribution of metabolic characteristics(mitochondria)within oocytes.This work provides a new perspective for clinical quality assessment and basic research of oocytes,and can open new doors for development of life science.

Effects of nitrogen ion implantation on lily pollen germination and the distribution of the actin cytoskeleton during pollen germination

The effects of low energy nitrogen ion implantation on lily (Lilium davidii Duch.) pollen germination and the distribution of the actin cytoskeleton during pollen germination have been studied. Preliminary results showed that the ratio of pollen germination increased from (16.0±1.6)% to (27.0±2.1)% when implanted with nitrogen ions by 100 keV and a dose of 1013 ions/cm2. Further experiments were performed by staining the actin filaments in pollen with rhodamine-phalloidin and detected by using laser confocol microscopy. After hydration for 10 h, the actin filaments in ion implanted pollen grains tended to form thick bundles oriented in parallel or ring shape at the germinal furrow, indicating that the effect of nitrogen ion implantation on the germination of pollen might be mediated by reorganization of the actin cytoskeleton.

A Bi-Functional Xyloglucan Galactosyltransferase Is an Indispensable Salt Stress Tolerance Determinant in Arabidopsis

Salinity is an abiotic stress that substantially limits crop production worldwide. To identify salt stress tolerance determinants, we screened for Arabidopsis mutants that are hypersensitive to salt stress and designated these mutants as short root in salt medium （rsa）. One of these mutants, rsa3-1, is hypersensitive to NaCI and LiCI but not to CsCI or to general osmotic stress. Reactive oxygen species （ROS） over-accumulate in rsa3-1 plants under salt stress. Gene expression profiling with Affymetrix microarray analysis revealed that RSA3 controls expression of many genes including genes encoding proteins for ROS detoxification under salt stress. Map-based cloning showed that RSA3 encodes a xyloglucan galactosyltransferase, which is allelic to a gene previously named MUR3/KAM1. The RSA3/ MUR3/KAMl-encoded xylogluscan galactosyltransferase regulates actin microfilament organization （and thereby con- tributes to endomembrane distribution） and is also involved in cell wall biosynthesis. In rsa3-1, actin cannot assemble and form bundles as it does in the wild-type but instead aggregates in the cytoplasm. Furthermore, addition of phal- Ioidin, which prevents actin depolymerization, can rescue salt hypersensitivity of rsa3-1. Together, these results sug- gest that RSA3/MUR3/KAM1 along with other cell wall-associated proteins plays a critical role in salt stress tolerance by maintaining the proper organization of actin microfilaments in order to minimize damage caused by excessive ROS.

Localization of Vibrio vulnificus infection in dendritic cells and its effects on the cytoskeleton

Background Vibrio vulnificus （Vv） is an estuadne bacterium that can cause primary septicemia as well as serious wound infections. However, little is known about the mechanisms by which Vv infects dendritic cells （DCs） and its effects on cytoskeleton. In this study, we aimed to investigate the invasion, internalization, and the organelles damage of the cultured dendritic cells （a DC 2.4 strain） during Vv infection. Methods The study model was the cultured DCs infected by a Vv 1.758 strain. Electron microscopy was used to observe the localization of bacteria at the different time points of infection, cell morphology, and the process of organelles changes. The cytoskeleton structure including the microfilaments and the microtubules rearrangement was examined under a fluorescence microscope. Results The Vv were pinocytosised into the DC cells through double-sides, and localized at 1-2 μm of the inner side membrane. It took 1.3, 1.9, and 3.4 hours to reach the infection ratio of 25%, 50%, and 75%, respectively. Using electron microscopy, the DCs had been observed to have developed chromatin aggregation within 4.0 hours, and significant cytoskeleton structure disruption was noted within 6.0 hours.

Actomyosin is Involved in the Organization of the Microtubule Preprophase Band in Arabidopsis Suspension Cultured Cells

The microtubule preprophase bands （PPBs） participate in the sequence of events to position cell plates in most plants. However, the mechanism of PPB formation remains to be clarified. In the present study, the organization of PPBs in Arabidopsis suspension cultured cells was investigated by confocal laser scanning microscopy combined with pharmacological treatments of reagents specific for the cytoskeleton elements. Double staining of F-actin and microtubules （MTs） showed that actin filaments were arranged randomly and no colocalization with cortical MTs was observed in the interphase cells. However, cortical actin filaments showed colocalization with MTs during the formation of PPBs. A broad actin band formed with the broad MT band in the initiation of PPB and narrowed down together with the MT band to form the PPB. Nevertheless, broad MT bands were formed but failed to narrow down in cells treated with the F-actin disruptor latrunculin A. In contrast, in the presence of the F-actin stabilizer phalloidin, PPB formation did not exhibit any abnormality. Therefore, the integrity, but not the dynamics, of the actin cytoskeleton is necessary for the formation of normal PPBs. Treatment with 2, 3-butanedine monoxime, a myosin inhibitor, also resulted in the formation of broad MT bands, indicating that actomyosin may be involved in the rearrangement of MTs to form the PPBs. Double staining of MTs and myosin revealed that myosin concentrated on the PPB region during PPB formation. It is suggested that the actin cytoskeleton at the PPB site may serve as a rack to transport cortical MTs by using myosin when the broad MT band narrows down to form the PPB.

Effects of microfllamentous depolymerization by cytochalasin B on cAMP-PKA pathway

Diacylglycerol (DG) and cAMP, two intracellular second messengers, play importantroles in responding to the stimulation of extracellular signal. DG activates protein kinaseC (PKC), and cAMP activates protein kinase A (PKA). Activation of these

Active bleb formation is abated in Lytechinus variegatus red spherule coelomocytes after disruption of acto-myosin contractility

Red spherule coelomocytes are immune cells in the sea urchin Lytechinus variegatus that have been characterizedas motile O2 transport cells. Video microscopy of living red spherule coelomocytes reveals a constitutive, dynamicarray of cellular morphologies and movements. Cells continuously send out and retract membrane blebs all over thecell surface as part of their normal cellular physiology. Disruption of microtubules by perfusion with either nocodazoleor taxol had no effect on bleb formation or motility. Perfusion with cytochalasin B abated bleb formation andrevealed cells that exhibited multiple small spheres attached by short membrane extensions. Attenuation of blebbingand intracellular organelle motility were restored by washing out with cytochalasin B. Treatment with phalloidinalso abated bleb formation and revealed a smooth, spherical cellular morphology. The effects of phalloidin werecompletely reversible after washout. Red spherule coelomocytes treated with blebbistatin rounded up with anirreversible retraction of blebs into surface blebs that were greatly reduced in size, number and motility. Normal cellsurface bleb formation and intracellular organelle motility were not restored after washout of the drug. These resultsindicate that the acto-myosin contractile mechanism contributes to the dynamics of constitutive cell surface membraneblebbing in invertebrate immune cells.

烟草表皮细胞薄层培养中第一次无丝分裂时的核及核外微丝骨架变化的观察

通过Hoechst33258和TRITC－Phalloidin对烟草茎表皮薄层培养细胞的非固定染色观察，发现细胞无丝分裂过程中核及其外围微丝鞘发生了很大变化．染色质在分裂时形成卷曲拉裂状，此时核外微丝鞘完全消失．直至染色质分开后，两组染色质由伸张状态回缩时，微丝鞘才重新聚合排列，并最后形成两个子核的微丝鞘．