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1.
Phytochem Anal ; 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38572825

RESUMO

INTRODUCTION: Sicklepod [Cassia obtusifolia L. syn Senna obtusifolia (L.) H.S. Irwin & Barneby, Fabaceae] sprouts are promising ingredients with health-promoting benefits. Notwithstanding, the pharmacologically active compounds in sicklepod sprouts have not been studied or analysed in detail. OBJECTIVE: This study aimed to isolate and structurally identify phytochemicals showing α-glucosidase inhibitory activity in sicklepod sprouts and simultaneously quantify the compounds in the sprouts to determine the optimal cultivation method and germination time to maximise active compounds. METHOD: A simultaneous high-performance liquid chromatography-ultraviolet (HPLC-UV) method with high sensitivity and accuracy was developed and used to analyse time-dependent changes in anthraquinone content during sicklepod germination. RESULTS: Thirteen anthraquinones were isolated and identified, of which six-chrysoobtusin, emodin, 1-O-methyl-2-methoxychrysophanol, 7-O-methylobtusin, chrysophanol, and physcion-showed moderate α-glucosidase inhibitory activity. The maximum content of anthraquinones in a sprout was observed on Day 5 under both light and dark conditions. CONCLUSION: The findings of this study revealed that sicklepod sprouts which are promising functional food materials contain a variety of anthraquinones.

2.
Phys Rev E ; 108(4-2): 045207, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37978721

RESUMO

With the advancement in the understanding of plasma discontinuous structures and the progress of related research, numerical methods for simulating plasmas based on continuous medium approach have encountered significant challenges. In this paper, a numerical model is presented to simulate the motion trajectory of an atmospheric pressure plasma jet under an external nonuniform electric field. The method proposes to treat the plasma jet as equivalent particles with permittivity and conductivity, based on its dielectric properties and motion characteristics. The numerical model demonstrates short calculation times and excellent agreement between simulation results and experimental observations, validating its high efficiency and effectiveness. This work contributes to a deeper understanding of the collective effect of the plasma jet and provides an effective and efficient method for predicting the motion trajectory of the plasma jet, along with guidelines for controlling plasma using external nonuniform electric fields.

3.
J Neuroendovasc Ther ; 17(9): 202-208, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37731467

RESUMO

Objective: This is a report on the usefulness of 3D fusion imaging with susceptibility-weighted imaging (SWI) as preoperative imaging for mechanical thrombectomy (MT) for acute ischemic stroke (AIS). Case Presentations: Among 17 cases of patients who underwent MT in AIS between March 2021 and April 2022, 14 patients who underwent MRI with SWI (shortened SWI for stroke) and 3D T2-weighted sampling perfection with application-optimized contrasts using different flip angle evolution were targeted in the study. Three cases with motion artifacts due to body movement were excluded from the images.After imaging, 3D fusion images were constructed to visualize thrombi and occluded vessels. SWI for stroke obtained thrombus information in 11 of the 14 cases (78.5%) and 3D images of the thrombi could be created in all 11 cases. 3D fusion images could be created in nine of the 14 cases (64.2%). Conclusion: 3D fusion images, using SWI for stroke, can visualize thrombi and occluded vessels and may be effectively used as preoperative images for MT.

4.
Surg Neurol Int ; 14: 165, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37292402

RESUMO

Background: The ventriculus terminalis (VT) is a cystic embryological remnant of the conus medullaris that usually regresses after birth. This structure rarely persists into adulthood and may produce neurological symptoms. We recently encountered three cases of symptomatic enlarging VT. Case Description: The three female patients were 78, 64, and 67 years old. Symptoms included pain, numbness, motor weakness, and frequent urination that gradually worsened. Magnetic resonance imaging revealed cystic dilatations of slow growing VT. These patients showed marked improvement after cyst-subarachnoid shunt using a syringo-subarachnoid shunt tube. Conclusion: Symptomatic enlarging VT is an extremely rare cause of conus medullaris syndrome and the optimal treatment strategy remains unclear. Surgical management may thus be appropriate for patients with symptomatic enlarging VT.

5.
Cureus ; 14(2): e22484, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35371681

RESUMO

OBJECTIVE: To extend life expectancy after surgery, patients with hip fractures need to improve their mobility quickly through postoperative rehabilitation. Voluntary hip joint motion supported by the hybrid assistive limb (HAL) lumbar type, an exoskeleton robot suit characterized by its ability to detect the wearer's intentions through the bioelectrical signals and assist hip extension motions at an optimal timing, may be effective to improve mobility in patients with hip joint dysfunction after surgery. We aimed to introduce rehabilitation using the HAL lumbar type in the early period after hip fracture surgery. METHODS: Patients who underwent internal fixation for hip fracture at a single institution were prospectively enrolled. They received early postoperative rehabilitation (forward and backward bending of the lumbar spine, pelvic tilt forward and backward, standing up, and squatting) using the HAL lumbar type (six times a week for 15 min per session). Five-times-sit-to-stand (FTSS) and timed-up-and-go (TUG) tests were conducted at baseline before HAL rehabilitation (pre-HAL) and after the HAL rehabilitation (post-HAL) intervention. RESULTS: We enrolled 14 patients (one man, 13 women) in this study. There were no adverse events, and all patients were able to complete the entire rehabilitation program. Post-HAL FTSS showed significant improvement compared with pre-HAL and had a large effect size of 1.81 (95% CI = 0.93 to 2.66) and sufficient power. CONCLUSIONS: Robotic rehabilitation with HAL lumbar type could be introduced without adverse events, even in the early postoperative period following surgery for hip fracture. Further study is needed to develop an appropriate rehabilitation protocol using the HAL lumbar type.

6.
Childs Nerv Syst ; 38(9): 1803-1807, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35083514

RESUMO

The purpose of treatment for unilocular intracranial cysts (UICs) is to release elevated intracranial pressure. Neuroendoscopic fenestration (NF) is one of the most effective and minimally invasive options for treating UICs, especially in young children; however, the optimal location and number of fenestrations, the necessity of using endoscopic third ventriculostomy (ETV) in combination with fenestration, and the course of treatment are not well known. We retrospectively reviewed the hospital records between 2012 and 2019. The patients were studied in terms of sex, age at surgery, preoperative symptoms, cyst localization and size, course of treatment, ventricular diameter, developmental assessment, anatomical location, and the number of fenestrations. There were four eligible patients in the relevant period: two boys and two girls. The median age at the time of surgery was 16 months. With regard to the location of the cysts, there were two cases of cavum velum interpositum (CVI), one case of quadrigeminal cistern, and one case of an isolated lateral ventricle. The most common preoperative finding was an enlarged head circumference. All the patients were treated with NF, including one case of reoperation after open head surgery. Postoperatively, we used the frontal and occipital horn ratio (FOHR) to evaluate the ventricular size. The average reduction in the FOHR was 0.003. In the most recent developmental assessment or examination during the follow-up period, two patients showed normal development, and two patients showed developmental delay. Based on our past experience and reports, we believe that it is recommended to perform two fenestrations for a single cyst. This is because it creates a flow of cerebrospinal fluid (CSF) within the cyst into normal CSF reflux. For lesions with obstruction of the aqueduct, such as cysts in the quadrigeminal cistern, ETV should be considered if it can be performed safely, in preparation for the worsening of hydrocephalus due to obstruction by enlargement of the cyst.


Assuntos
Cistos , Hidrocefalia , Neuroendoscopia , Criança , Pré-Escolar , Cistos/cirurgia , Feminino , Humanos , Hidrocefalia/diagnóstico por imagem , Hidrocefalia/etiologia , Hidrocefalia/cirurgia , Ventrículos Laterais/patologia , Masculino , Estudos Retrospectivos , Resultado do Tratamento , Ventriculostomia
7.
J Neuroendovasc Ther ; 16(9): 452-457, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37502793

RESUMO

Objective: Determining the course of occluded vessels in advance will increase the success rate and safety of mechanical thrombectomy (MT). Herein, we evaluate the usefulness of MR fusion images created via 3D T2-weighted sampling perfection with application-optimized contrasts using different flip angle evolutions (T2-SPACE) and 3D time-of-flight (TOF)-MRA for visualization of occluded vessels in patients with acute ischemic stroke (AIS) before MT. Methods: We enrolled 26 patients with AIS caused by intracranial large vessel occlusion who presented at our hospital and underwent MRI with fusion images unaffected by motion artifacts in our study. All patients underwent T2-SPACE and TOF-MRA followed by MT. We created fusion images of the T2-SPACE and TOF-MRA by combining a translucent image of the occluded artery produced by the flow void effect in T2-SPACE with the same vessel in a TOF-MRA image. Fusion images were compared with post-recanalization angiography and post-recanalization MRA, respectively, and the degree of agreement in depiction of M1 runs and M2 branching beyond the occlusion on three levels was assessed. Imaging evaluations were performed independently by two endovascular specialists. Results: The interobserver agreement of the MRI findings about the concordance of the occluded vessel's run was excellent (kappa was 0.87 [confidence interval: 0.61-1.12]). In all, 21 patients (80.8%) had excellent imaging, four (15.4%) had fair imaging, and one (3.8%) had a divided opinion of the rating between excellent and fair imaging. No cases were judged to be poorly drawn. Even if there was a localized signal loss, its distal portion could be delineated, so it did not affect the estimation of the entire vessel run, and we found that the anatomical structures of the occluded vessels were distinctly visible in the fusion images. Conclusion: We demonstrated that MR fusion images derived using T2-SPACE and MRA methodologies could determine the courses of occluded vessels prior to MT performed for AIS. Fusion MR imaging may have potential as a preoperative test for ensuring effective and safe MT procedures.

8.
Plant Cell Physiol ; 62(12): 1874-1889, 2021 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-34197607

RESUMO

All land plants encode large multigene families of xyloglucan endotransglucosylase/hydrolases (XTHs), plant-specific enzymes that cleave and reconnect plant cell-wall polysaccharides. Despite the ubiquity of these enzymes, considerable uncertainty remains regarding the evolutionary history of the XTH family. Phylogenomic and comparative analyses in this study traced the non-plant origins of the XTH family to Alphaproteobacteria ExoKs, bacterial enzymes involved in loosening biofilms, rather than Firmicutes licheninases, plant biomass digesting enzymes, as previously supposed. The relevant horizontal gene transfer (HGT) event was mapped to the divergence of non-swimming charophycean algae in the Cryogenian geological period. This HGT event was the likely origin of charophycean EG16-2s, which are putative intermediates between ExoKs and XTHs. Another HGT event in the Cryogenian may have led from EG16-2s or ExoKs to fungal Congo Red Hypersensitive proteins (CRHs) to fungal CRHs, enzymes that cleave and reconnect chitin and glucans in fungal cell walls. This successive transfer of enzyme-encoding genes may have supported the adaptation of plants and fungi to the ancient icy environment by facilitating their sessile lifestyles. Furthermore, several protein evolutionary steps, including coevolution of substrate-interacting residues and putative intra-family gene fusion, occurred in the land plant lineage and drove diversification of the XTH family. At least some of those events correlated with the evolutionary gain of broader substrate specificities, which may have underpinned the expansion of the XTH family by enhancing duplicated gene survival. Together, this study highlights the Precambrian evolution of life and the mode of multigene family expansion in the evolutionary history of the XTH family.


Assuntos
Parede Celular/enzimologia , Embriófitas/enzimologia , Evolução Molecular , Família Multigênica , Proteínas de Plantas/genética , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Proteínas de Plantas/metabolismo
9.
Acta Radiol Open ; 10(3): 20584601211003233, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33815831

RESUMO

High-resolution vessel wall imaging techniques have been developed for clinical use in various types of intracranial artery disease. Numerous studies have described techniques for evaluating remodeling patterns and plaque character, but few have reported a method for outlining obstructed vessels in intracranial artery occlusion. The course of the vessel affects the success of recanalization and can cause complications in mechanical thrombectomy for acute ischemic stroke. We propose imaging with 3D T2-weighted sampling perfection with application optimized contrasts using different flip angle evolution (SPACE) as a useful tool for describing the course of an occluded artery in ischemic stroke due to intracranial artery occlusion.

10.
Front Plant Sci ; 11: 193, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32231674

RESUMO

The genus Cuscuta is stem parasitic angiosperms that parasitize a wide range of vascular plants via de novo formation of a distinctive parasitic organ called a haustorium. In the developing haustorium, meristematic cells, which are initiated from the stem cortical tissue, differentiate into haustorial parenchyma cells, which elongate, penetrate into the host tissues, and finally connect with the host vasculature. This interspecific vasculature connection allows the parasite to uptake water and nutrients from the host plant. Although histological aspects of haustorium development have been studied extensively, the molecular mechanisms underlying vasculature development and the interspecific connection with the host vasculature remain largely unknown. To gain insights into the interspecific cell-to-cell interactions involved in haustorium development, we established an in vitro haustorium induction system for Cuscuta campestris using Arabidopsis thaliana rosette leaves as the host plant tissue. The in vitro induction system was used to show that interaction with host tissue was required for the differentiation of parasite haustorial cells into xylem vessel cells. To further characterize the molecular events occurring during host-dependent xylem vessel cell differentiation in C. campestris, we performed a transcriptome analysis using samples from the in vitro induction system. The results showed that orthologs of genes involved in development and proliferation of vascular stem cells were up-regulated even in the absence of host tissue, whereas orthologs of genes required for xylem vessel cell differentiation were up-regulated only after some haustorial cells had elongated and contacted the host xylem. Consistent results were obtained by another transcriptome analysis of the haustorium development in C. campestris undergoing parasitization of an intact host plant. These findings suggest the involvement of host-derived signals in the regulation of non-autonomous xylem vessel differentiation and suggest that its connection to the host xylem during the haustorium development activates a set of key genes for differentiation into xylem vessel cells.

11.
Auris Nasus Larynx ; 47(5): 895-898, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31492578

RESUMO

OBJECTIVE AND IMPORTANCE: This is the first article regarding a transnasal Foreign bodies (FB) penetrating the spinal cord. We tried to remove it safely with a bilateral approach by performing a nasal endoscopy and partial laminectomy. CLINICAL PRESENTATION: During logging work, a tree hit the occipital region of a 47-year-old man, producing unconsciousness with left paresis. Although he did not remember his injuries due to traumatic amnesia, a computed tomography (CT) scan showed a metal rod lodged from the left side wall of the nasopharynx to the spinal column at the cranial-cervical transition. INTERVENTION: A C1 laminectomy, partial occipital bone resection, and endoscopic intranasal extirpation were done jointly by an otolaryngologist and neurosurgeon under general anesthesia to safely remove the FB. All procedures were performed in the right lateral decubitus position so we could approach both the nasopharynx and occipital sides. The otolaryngologist withdrew the FB from the nasal cavity using an endoscope while the neurosurgeon monitored the occipital bone side. The FB was safely removed. CONCLUSION: The site of penetration at the nasopharynx contracted gradually to a scar with no cerebrospinal fluid (CSF) leak. The patient was finally discharged 39 days after surgery with no motor/sensory paralysis.


Assuntos
Corpos Estranhos/cirurgia , Nasofaringe , Traumatismos da Medula Espinal/cirurgia , Medula Espinal/diagnóstico por imagem , Ferimentos Penetrantes/cirurgia , Acidentes de Trabalho , Corpos Estranhos/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Traumatismos da Medula Espinal/diagnóstico por imagem , Traumatismos da Medula Espinal/etiologia , Tomografia Computadorizada por Raios X , Artéria Vertebral/diagnóstico por imagem , Artéria Vertebral/lesões , Ferimentos Penetrantes/diagnóstico por imagem , Ferimentos Penetrantes/etiologia
12.
J Neuroendovasc Ther ; 14(10): 441-446, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-37502657

RESUMO

Objective: The course of the vessel affects the success of recanalization and can cause complications in mechanical thrombectomy (MT); however, no study has been reported a method for outlining vessel course prior to MT. We propose magnetic resonance (MR) fusion images as a useful tool in MT for acute ischemic stroke. Case Presentations: A 73-year-old woman and a 79-year-old man were admitted to our hospital with left hemiparesis. In both patients, MR revealed acute ischemic stroke due to right middle cerebral artery (MCA) occlusion. MR fusion images were created with 3D T2-weighted sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) and 3D time-of-flight (TOF) MRA acquired before MT clearly revealed the occluded right MCA. In both cases, the fusion image is enabled information about the course of the right MCA and its branches to be obtained prior to performing MT. The thrombi were removed with a stent retriever and reperfusion catheter with no complications, and there was remarkable resolution of symptoms in both patients immediately after the procedure. Conclusion: A fusion image of T2-weighted SPACE and 3D TOF MRA appears to be a simple and effective method for determining the course of the occluded vessel prior to MT for acute ischemic stroke. This technique will enable good recanalization in MT for acute ischemic stroke and should reduce complications.

13.
J Radiat Res ; 60(4): 417-423, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31197350

RESUMO

Millimeter waves are used in various fields, and the risks of this wavelength range for human health must be carefully evaluated. In this study, we investigated the effects of millimeter waves on genotoxicity and heat shock protein expression in human corneal epithelial (HCE-T) and human lens epithelial (SRA01/04) cells. We exposed the cells to 40-GHz millimeter waves at 1 mW/cm2 for 24 h. We observed no statistically significant increase in the micronucleus (MN) frequency or the level of DNA strand breaks in cells exposed to 40-GHz millimeter waves relative to sham-exposed and incubator controls. Heat shock protein (Hsp) expression also exhibited no statistically significant response to the 40-GHz exposure. These results indicate that exposure to 40 GHz millimeter waves under these conditions has little or no effect on MN formation, DNA strand breaks, or Hsp expression in HCE-T or SRA01/04 cells.


Assuntos
Córnea/citologia , Campos Eletromagnéticos , Células Epiteliais/citologia , Proteínas de Choque Térmico/metabolismo , Linhagem Celular , Ensaio Cometa , Dano ao DNA , Regulação da Expressão Gênica , Humanos , Testes para Micronúcleos
14.
World Neurosurg ; 129: e352-e360, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31132492

RESUMO

BACKGROUND: After aneurysmal subarachnoid hemorrhage (aSAH), crystalloid fluids with a relatively high sodium concentration have been used to maintain the cerebral blood flow. However, the prophylactic delivery of water and sodium by intravenous (IV) infusion will not necessarily improve the prognosis of patients after aSAH, and the excessive supply of water and sodium can negatively affect the outcome. We hypothesized that the delivery of an optimal amount of water and sodium separately might improve the outcome after aSAH. METHODS: We recruited 55 consecutive patients who had undergone clipping or endovascular coil embolization after aSAH. Group 1 (n = 33) received conventional therapy (i.e., prophylactic IV sodium and water [protocol 1]). Group 2 (n = 22) received the optimal amount of water and sodium separately (protocol 2). RESULTS: The median total of water and sodium chloride supplied in group 1 was significantly greater than that supplied in group 2 (P < 0.01). The modified Rankin scale score at discharge was 0-2 in 15 patients (95%) in group 2 and 23 patients (55%) in group 1 (P < 0.001). On multivariate logistic regression analysis, the odds ratio for a discharge modified Rankin scale score of 0-2 or 3-6 was significantly associated with the treatment protocol (P < 0.05) and the net fluid balance on days 4-8 (P < 0.05). CONCLUSION: The separate delivery of optimal amounts of water and sodium could be a promising therapeutic strategy to improve the prognosis after aSAH.


Assuntos
Embolização Terapêutica , Hidratação/métodos , Cuidados Pós-Operatórios/métodos , Hemorragia Subaracnóidea/terapia , Equilíbrio Hidroeletrolítico/fisiologia , Administração Intravenosa , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Hemorragia Subaracnóidea/fisiopatologia , Resultado do Tratamento
15.
IEEE Trans Nanobioscience ; 18(2): 257-260, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30892224

RESUMO

In the near future, electrification will be introduced to heavy-duty vehicles and passenger cars. However, the wireless power transfer (WPT) requires high energy levels, and the suitability of various types of WPT systems must be assessed. This paper describes a method for solving technical and safety issues associated with this technology. We exposed human corneal epithelial (HCE-T) cells derived from the human eye to 5.8-GHz electromagnetic fields for 24 h. We observed no statistically significant increase in micronucleus (MN) frequency in cells exposed to a 5.8-GHz field at 1 mW/cm2 (the general public level in ICNIRP) relative to sham-exposed or incubator controls. Similarly, the DNA strand breaks, and the expression of heat shock protein (Hsp) Hsp27, Hsp70, and Hsp 90α exhibited no statistically significant effects as a result of exposure. These results indicate that the exposure to 5.8-GHz electromagnetic fields at 1 mW/cm2 for 24 h has little or no effect on micronucleus formation, DNA strand breaks, and Hsp expression in human eye cells.


Assuntos
Quebras de DNA , Campos Eletromagnéticos , Epitélio Corneano/citologia , Proteínas de Choque Térmico/metabolismo , Micronúcleos com Defeito Cromossômico , Linhagem Celular , Epitélio Corneano/metabolismo , Humanos
16.
J Radiat Res ; 59(5): 547-554, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29961812

RESUMO

High-dose ionizing radiation is sufficient for breaking DNA strands, leading to cell death and mutations. By contrast, the effects of fractionated ionizing radiation on human-derived cells remain unclear. To better understand the genotoxic effects of fractionated ionizing radiation, as well as the cellular recovery rate, we investigated the frequency of micronucleus (MN) formation in various types of human cells. We irradiated cells with fractionated X-ray doses of 2 Gy at a rate of 0.0635 Gy/min, separated into two to eight smaller doses. After irradiation, we investigated the frequency of MN formation. In addition, we investigated the rate of decrease in MN frequency after irradiation with 1 or 2 Gy X-rays at various recovery periods. Fractionated irradiation decreased MN frequency in a dose-dependent manner. When the total dose of X-rays was the same, the MN frequencies were lower after fractionated X-ray irradiation than acute irradiation in every cell type examined. The rate of MN decrease was faster in KMST-6 cells, which were derived from a human embryo, than in the other cells. The rate of MN decrease was higher in cells exposed to fractionated X-rays than in those exposed to acute irradiation. Recovery rates were very similar among cell lines, except in KMST-6 cells, which recovered more rapidly than other cell types.


Assuntos
Linhagem Celular/efeitos da radiação , Fracionamento da Dose de Radiação , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Testes para Micronúcleos , Pré-Escolar , Dano ao DNA , Relação Dose-Resposta à Radiação , Fibroblastos/metabolismo , Células HeLa , Humanos , Lactente , Cinética , Doses de Radiação , Radiação Ionizante , Radiografia , Reprodutibilidade dos Testes , Raios X
17.
Materials (Basel) ; 11(1)2018 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-29361758

RESUMO

Microwave (MW) heating has received attention as a new heating source for various industrial processes. Some materials are expected to be a more effective absorber of MW, and graphite is observed as a possible candidate for high-temperature application. We investigated the dependence of the aspect ratio of graphite fibers on both their heating behavior and permittivity under a 2.45 GHz MW electric field. In these experiments, both loss tangent and MW heating behavior indicated that the MW absorption of conductive fibers increases with their aspect ratio. The MW absorption was found to be well accounted for by the application of a spheroidal model for a single fiber. The absorption of graphite fibers decreases with increasing aspect ratio when the long axis of the ellipsoid is perpendicular to the electric field, whereas it increases with the aspect ratio when the long axis is parallel to the electric field. The analytical model indicated that MW heating of the conductive fibers is expected to depend on both the shape and arrangement of the fibers in the electric field.

18.
Plant Cell ; 29(10): 2644-2660, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28899981

RESUMO

Ribosome-related mutants in Arabidopsis thaliana share several notable characteristics regarding growth and development, which implies the existence of a common pathway that responds to disorders in ribosome biogenesis. As a first step to explore this pathway genetically, we screened a mutagenized population of root initiation defective2 (rid2), a temperature-sensitive mutant that is impaired in pre-rRNA processing, and isolated suppressor of root initiation defective two1 (sriw1), a suppressor mutant in which the defects of cell proliferation observed in rid2 at the restrictive temperature was markedly rescued. sriw1 was identified as a missense mutation of the NAC transcription factor gene ANAC082 The sriw1 mutation greatly alleviated the developmental abnormalities of rid2 and four other tested ribosome-related mutants, including rid3 However, the impaired pre-rRNA processing in rid2 and rid3 was not relieved by sriw1 Expression of ANAC082 was localized to regions where phenotypic effects of ribosome-related mutations are readily evident and was elevated in rid2 and rid3 compared with the wild type. These findings suggest that ANAC082 acts downstream of perturbation of biogenesis of the ribosome and may mediate a set of stress responses leading to developmental alterations and cell proliferation defects.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Processamento Pós-Transcricional do RNA/fisiologia , Ribossomos/metabolismo
19.
Sci Rep ; 7: 46099, 2017 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-28443615

RESUMO

Cellulose is an economically important material, but routes of its industrial processing have not been fully explored. The plant cell wall - the major source of cellulose - harbours enzymes of the xyloglucan endotransglucosylase/hydrolase (XTH) family. This class of enzymes is unique in that it is capable of elongating polysaccharide chains without the requirement for activated nucleotide sugars (e.g., UDP-glucose) and in seamlessly splitting and reconnecting chains of xyloglucan, a naturally occurring soluble analogue of cellulose. Here, we show that a recombinant version of AtXTH3, a thus far uncharacterized member of the Arabidopsis XTH family, catalysed the transglycosylation between cellulose and cello-oligosaccharide, between cellulose and xyloglucan-oligosaccharide, and between xyloglucan and xyloglucan-oligosaccharide, with the highest reaction rate observed for the latter reaction. In addition, this enzyme formed cellulose-like insoluble material from a soluble cello-oligosaccharide in the absence of additional substrates. This newly found activity (designated "cellulose endotransglucosylase," or CET) can potentially be involved in the formation of covalent linkages between cellulose microfibrils in the plant cell wall. It can also comprise a new route of industrial cellulose functionalization.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Parede Celular/enzimologia , Celulose/metabolismo , Reagentes de Ligações Cruzadas/química , Glicosiltransferases/metabolismo , Oligossacarídeos/metabolismo , Células Vegetais/enzimologia , Biocatálise , Glicosilação , Concentração de Íons de Hidrogênio , Cinética , Especificidade por Substrato , Temperatura
20.
Plant Direct ; 1(6): e00021, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31245675

RESUMO

The network structure of cellulose fibrils provides mechanical properties to the primary cell wall, thereby determining the shapes and growth patterns of plant cells. Despite intensive studies, the construction process of the network structure in muro remains largely unknown, mainly due to the lack of a robust, straightforward technique to evaluate network configuration. Here, we developed a quantitative confocal imaging method for general use in the study of cell wall dynamics in protoplasts derived from Arabidopsis leaf mesophyll cells. Confocal imaging of regenerating cell walls in protoplasts stained with Calcofluor allowed us to visualize the cellulose network, comprising strings of bundled cellulosic fibrils. Using image analysis techniques, we measured several metrics including total length, which is a measure of the spread of the cellulose network. The total length increased during cell wall regeneration. In a proof-of-concept experiment using microtubule-modifying agents, oryzalin, an inhibitor of microtubule polymerization, inhibited the increase in total length and caused abnormal orientation of the network, as shown by the decrease in the average angle of the cellulose with respect to the cell long axis. Taxol, a microtubule stabilizer, stimulated the bundling of cellulose fibrils, as shown by the increase in skewness in the fluorescence intensity distribution of Calcofluor, and inhibited the increase in total length. These results demonstrate the validity of this method for quantitative imaging of the cellulose network, providing an opportunity to gain insight into the dynamic aspects of cell wall regeneration.

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