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Callose, a ß-(1,3)-d-glucan polymer, is essential for regulating intercellular trafficking via plasmodesmata (PD). Pathogens manipulate PD-localized proteins to enable intercellular trafficking by removing callose at PD or, conversely, by increasing callose accumulation at PD to limit intercellular trafficking during infection. Plant defense hormones like salicylic acid regulate PD-localized proteins to control PD and intercellular trafficking during immune defense responses such as systemic acquired resistance. Measuring callose deposition at PD in plants has therefore emerged as a popular parameter for assessing likely intercellular trafficking activity during plant immunity. Despite the popularity of this metric, there is no standard for how these measurements should be made. In this study, three commonly used methods for identifying and quantifying plasmodesmal callose by aniline blue staining were evaluated to determine the most effective in the Nicotiana benthamiana leaf model. The results reveal that the most reliable method used aniline blue staining and fluorescence microscopy to measure callose deposition in fixed tissue. Manual or semiautomated workflows for image analysis were also compared and found to produce similar results, although the semiautomated workflow produced a wider distribution of data points. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Glucanos , Nicotiana , Doenças das Plantas , Folhas de Planta , Plasmodesmos , Glucanos/metabolismo , Nicotiana/metabolismo , Plasmodesmos/metabolismo , Folhas de Planta/metabolismo , Doenças das Plantas/microbiologia , Compostos de Anilina/metabolismo , Imunidade Vegetal , Coloração e Rotulagem/métodosRESUMO
BACKGROUND: Androgen deprivation therapy (ADT) in prostate cancer (PCa) has been associated with development of insulin resistance. However, the predominant site of insulin resistance remains unclear. METHODS: The ADT & Metabolism Study was a single-center, 24-week, prospective observational study that enrolled ADT-naive men without diabetes who were starting ADT for at least 24 weeks (ADT group, n = 42). The control group comprised men without diabetes with prior history of PCa who were in remission after prostatectomy (non-ADT group, n = 23). Prevalent diabetes mellitus was excluded in both groups using all three laboratory criteria defined in the American Diabetes Association guidelines. All participants were eugonadal at enrollment. The primary outcome was to elucidate the predominant site of insulin resistance (liver or skeletal muscle). Secondary outcomes included assessments of body composition, and hepatic and intramyocellular fat. Outcomes were assessed at baseline, 12, and 24 weeks. RESULTS: At 24 weeks, there was no change in hepatic (1.2; 95% confidence interval [CI], -2.10 to 4.43; p = .47) or skeletal muscle (-3.2; 95% CI, -7.07 to 0.66; p = .10) insulin resistance in the ADT group. No increase in hepatic or intramyocellular fat deposition or worsening of glucose was seen. These changes were mirrored by those observed in the non-ADT group. Men undergoing ADT gained 3.7 kg of fat mass. CONCLUSIONS: In men with PCa and no diabetes, 24 weeks of ADT did not change insulin resistance despite adverse body composition changes. These findings should be reassuring for treating physicians and for patients who are being considered for short-term ADT.
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We present a case study detailing cognitive performance, functional neuroimaging, and effects of a hypothesis-driven treatment in a 10-year-old girl diagnosed with complete, isolated corpus callosum agenesis. Despite having average overall intellectual abilities, the girl exhibited profound surface dyslexia and dysgraphia. Spelling treatment significantly and persistently improved her spelling of trained irregular words, and this improvement generalized to reading accuracy and speed of trained words. Diffusion weighted imaging revealed strengthened intrahemispheric white matter connectivity of the left temporal cortex after treatment and identified interhemispheric connectivity between the occipital lobes, likely facilitated by a pathway crossing the midline via the posterior commissure. This case underlines the corpus callosum's critical role in lexical reading and writing. It demonstrates that spelling treatment may enhance interhemispheric connectivity in corpus callosum agenesis through alternative pathways, boosting the development of a more efficient functional organization of the visual word form area within the left temporo-occipital cortex.
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BACKGROUND: Hospital-acquired hyponatremia remains a feared event in patients receiving hypotonic fluid therapy. Our objectives were to assess post-operative plasma-sodium concentration and to provide a physiological explanation for plasma-sodium levels over time in children with acute appendicitis. METHODS: Thirteen normonatremic (plasma-sodium ≥135 mmol/L) children (8 males), median age 12.3 (IQR 11.5-13.5) years participated in this prospective observational study (ACTRN12621000587808). Urine was collected and analyzed. Blood tests, including renin, aldosterone, arginine-vasopressin, and circulating nitric oxide substrates were determined on admission, at induction of anesthesia, and at the end of surgery. RESULTS: On admission, participants were assumed to be mildly dehydrated and were prescribed 50 mL/kg of Ringer's acetate intravenously followed by half-isotonic saline as maintenance fluid therapy. Blood tests, urinary indices, plasma levels of aldosterone, arginine-vasopressin, and net water-electrolyte balance indicated that participants were dehydrated on admission. Although nearly 50% of participants still had arginine-vasopressin levels that would have been expected to produce maximum antidiuresis at the end of surgery, electrolyte-free water clearance indicated that almost all participants were able to excrete net free water. No participant became hyponatremic. CONCLUSIONS: The use of moderately hypotonic fluid therapy after correction of extracellular fluid deficit is not necessarily associated with post-operative hyponatremia. IMPACT: Our observations show that in acutely ill normonatremic children not only the composition but also the amount of volume infused influence on the risk of hyponatremia. Our observations also suggest that perioperative administration of hypotonic fluid therapy is followed by a tendency towards hyponatremia if extracellular fluid depletion is left untreated. After correcting extracellular deficit almost all patients were able to excrete net free water. This occurred despite nearly 50% of the cohort having high circulating plasma levels of arginine-vasopressin at the end of surgery, suggesting a phenomenon of renal escape from arginine-vasopressin-induced antidiuresis.
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Hiponatremia , Criança , Humanos , Masculino , Aldosterona , Arginina , Arginina Vasopressina , Sódio , Vasopressinas , Água , Equilíbrio Hidroeletrolítico , Estudos ProspectivosRESUMO
AIM: Pelvic exenteration surgery can improve survival in people with advanced colorectal cancer. This systematic review aimed to review pain intensity and other outcomes, for example the management of pain, the relationship between pain and the extent of surgery and the impact of pain on short-term outcomes. METHOD: Electronic databases were searched from inception to 1 May 2021. We included interventional studies of adults with any indication for pelvic exenteration surgery that also reported pain outcomes. Risk of bias was assessed using ROBINS-1. RESULTS: The search found 21 studies that reported pain following pelvic exenteration [n = 1317 patients, mean age 58.4 years (SD 4.8)]. Ten studies were judged to be at moderate risk of bias. Before pelvic exenteration, pain was reported by 19%-100% of patients. Five studies used validated measures of pain intensity. No study measured pain at all three time points in the surgical journey. The presence of pain before surgery predicted postoperative adverse pain outcomes, and pain is more likely to be experienced in those who require wider resections, including bone resection. CONCLUSION: Considering that pain following pelvic exenteration is commonly described by patients, the literature suggests that this symptom is not being measured and therefore addressed.
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Neoplasias Colorretais , Exenteração Pélvica , Adulto , Humanos , Pessoa de Meia-Idade , Exenteração Pélvica/efeitos adversos , Manejo da Dor , Neoplasias Colorretais/cirurgia , Dor Pós-Operatória/etiologia , Estudos Retrospectivos , Recidiva Local de Neoplasia/cirurgiaRESUMO
Under anaerobic stress, Arabidopsis thaliana induces the expression of a collection of core hypoxia genes that encode proteins for an adaptive response. Among these genes is NIP2;1, which encodes a member of the "Nodulin 26-like Intrinsic Protein" (NIP) subgroup of the aquaporin superfamily of membrane channel proteins. NIP2;1 expression is limited to the "anoxia core" region of the root stele under normal growth conditions, but shows substantial induction (up to 1,000-fold by 2-4 h of hypoxia) by low oxygen stress, and accumulation in all root tissues. During hypoxia, NIP2;1-GFP accumulates predominantly on the plasma membrane by 2 h, is distributed between the plasma and internal membranes during sustained hypoxia, and remains elevated in root tissues through 4 h of reoxygenation recovery. In response to hypoxia challenge, T-DNA insertion mutant nip2;1 plants exhibit elevated lactic acid within root tissues, reduced efflux of lactic acid, and reduced acidification of the external medium compared to wild-type plants. Previous biochemical evidence demonstrates that NIP2;1 has lactic acid channel activity, and our work supports the hypothesis that NIP2;1 prevents lactic acid toxicity by facilitating release of cellular lactic acid from the cytosol to the apoplast, supporting eventual efflux to the rhizosphere. In evidence, nip2;1 plants demonstrate poorer survival during argon-induced hypoxia stress. Expressions of the ethanolic fermentation transcript Alcohol Dehydrogenase1 and the core hypoxia-induced transcript Alanine Aminotransferase1 are elevated in nip2;1, and expression of the Glycolate Oxidase3 transcript is reduced, suggesting NIP2;1 lactic acid efflux regulates other pyruvate and lactate metabolism pathways.
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Adaptação Fisiológica/genética , Aquaporinas/genética , Aquaporinas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Hipóxia/metabolismo , Ácido Láctico/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Hipóxia/genética , Plantas Geneticamente ModificadasRESUMO
OBJECTIVE: The purpose of this paper is to define the microbiome of the head and neck by characterizing and distinguishing the commensal bacteria from pathogenic species. STUDY DESIGN: Literature review. METHODS: Pubmed and Google scholar databases were queried for relevant articles. Keywords such as "middle ear microbiome", "outer ear microbiome", "sinonasal microbiome", "tonsil microbiome", and "laryngeal microbiome" were utilized separately to identify articles pertaining to each topic of study. All applicable abstracts were chosen for initial review and relevant abstracts were then selected for review of the full texts. Articles that did not study the human microbiome, those not written primarily in English, those that were not readily available for full review, and case reports were excluded from the study. RESULTS: Limited studies that investigate the microbial environments of isolated anatomic subsites in the head and neck exist, however the comprehensive microbiome of the head and neck has yet to be completely defined. Based on this review, various studies of the ears, larynx, tonsils and sinus microbiomes exist and yield valuable information, however they are limited in scope and anatomic subsite. In this literature review, these studies are compiled in order to create a comprehensive text inclusive of the known microbial elements of the major anatomic subsites of the head and neck, namely the tonsils, larynx, sinus, outer ear and middle ear. CONCLUSIONS: The significance of the human microbiome in identifying and preventing disease has been established in various physiologic systems, however there is limited research on the microbiome of the head and neck. Understanding the microbiome of the head and neck can help differentiate disease-prone patients from normal patients and guide treatment regimens and antibiotic usage, to aid in resistance control and limit adverse effects of antibiotic overuse. Understanding the elements that lead to dysbiosis can help treat and even prevent common conditions as tonsillitis and rhinosinusitis. In this review, we provide a comprehensive review to serve as an initial background for future studies to define the head and neck microbiome distinguished by all relevant subsites.
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Orelha/microbiologia , Cabeça/microbiologia , Microbiota , Pescoço/microbiologia , Antibacterianos/uso terapêutico , Disbiose/microbiologia , HumanosRESUMO
Maize brown sheath spot (MBSS), a new disease of maize, was discovered while surveying for maize leaf and sheath blight diseases in the Indian states of Assam, Jharkhand, Meghalaya, Manipur, and Odisha. Maize is the third most important cereal after rice and wheat in India. Unlike banded leaf and sheath blight disease caused by Rhizoctonia solani, MBSS symptoms on maize were discrete and limited to sheaths only. Symptoms of MBSS in the field were initially water-soaked necrotic lesions of 1 to 2 cm in diameter on the lowermost leaf sheaths, which then progressed to the upper sheaths. Lesions coalesced and covered approximately 2 to 5% of the sheath area. Infected dried lower leaves were shed, whereas infected upper leaves remained on the stem. The pathogen was isolated, characterized morphologically, pathologically, and molecularly, and identified as Waitea circinata var. prodigus, a basidiomycete known to cause basal leaf blight of seashore paspalum. The internal transcribed spacer (ITS) sequence 2 (ITS2) of rDNA from MBSS isolates formed a well supported clade with known W. circinata var. prodigus isolates. Molecular morphometric analysis of the ITS2 regions of the five known varieties of W. circinata detected distinguishing variations in GC content, compensatory base changes (CBCs), hemi- CBCs, indels, and altered base-pairing of helices. Variation in these characteristics may indicate that varieties are distinct biological species within W. circinata sensu lato. The geographical distribution and potential impacts of MBSS on the maize crop in India necessitate further investigations of pathogen identification and disease management.
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Basidiomycota , Zea mays , Índia , Doenças das Plantas/genética , Zea mays/genéticaRESUMO
Picloram is an auxinic herbicide that is widely used for controlling broad leaf weeds. However, its mechanism of transport into plants is poorly understood. In a genetic screen for picloram resistance, we identified three Arabidopsis mutant alleles of PIC30 (PICLORAM RESISTANT30) that are specifically resistant to picolinates, but not to other auxins. PIC30 is a previously uncharacterized gene that encodes a major facilitator superfamily (MFS) transporter. Similar to most members of MFS, PIC30 contains 12 putative transmembrane domains, and PIC30-GFP fusion protein selectively localizes to the plasma membrane. In planta transport assays demonstrate that PIC30 specifically transports picloram, but not indole-3-acetic acid (IAA). Functional analysis of Xenopus laevis oocytes injected with PIC30 cRNA demonstrated PIC30 mediated transport of picloram and several anions, including nitrate and chloride. Consistent with these roles of PIC30, three allelic pic30 mutants are selectively insensitive to picolinate herbicides, while pic30-3 is also defective in chlorate (analogue of nitrate) transport and also shows reduced uptake of 15NO3- . Overexpression of PIC30 fully complements both picloram and chlorate insensitive phenotypes of pic30-3. Despite the continued use of picloram as an herbicide, a transporter for picloram was not known until now. This work provides insight into the mechanisms of plant resistance to picolinate herbicides and also shed light on the possible endogenous function of PIC30 protein.
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Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte/metabolismo , Herbicidas/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Ácidos Picolínicos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Transporte/genética , Cloratos/metabolismo , Resistência a Herbicidas/genética , Proteínas de Membrana Transportadoras/genética , Mutação , Nitratos/metabolismoRESUMO
BACKGROUND: Improved survival has led to increasing numbers of children with life-limiting conditions transitioning to adult healthcare services. There are concerns that transition may lead to a reduction in care quality and increases in emergency care. This review explores evidence for differences in health or social care use post- versus pre-transition to adult services. METHODS: MEDLINE, EMBASE, CINAHL, PsychINFO and Social Science Citation Index were searched. Studies published in English since 1990 including individuals with any life-limiting condition post- and pre-transition and reporting a health or social care use outcome were included. Data were extracted and quality assessed by one reviewer with 30% checked by an independent reviewer. RESULTS: Nineteen papers (18 studies) met the inclusion criteria. There was evidence for both increases and decreases (post- versus pre-transition) in outpatient attendance, inpatient admissions, inpatient bed days and health service costs; for increases in Emergency Department visits and for decreases in individuals receiving physiotherapy. CONCLUSIONS: Evidence for changes in healthcare use post- versus pre-transition is mixed and conflicting, although there is evidence for an increase in Emergency Department visits and a reduction in access to physiotherapy. More high-quality research is needed to better link changes in care to the transition. IMPACT: Evidence for changes in healthcare use associated with transition to adult services is conflicting. Emergency Department visits increase and access to physiotherapy decreases at transition. There are marked differences between care patterns in the United States and Canada.
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Continuidade da Assistência ao Paciente , Doente Terminal , Adolescente , Canadá , Criança , Serviço Hospitalar de Emergência , Humanos , Apoio Social , Estados UnidosRESUMO
Water and ligand binding play critical roles in the structure and function of proteins, yet their binding sites and significance are difficult to predict a priori. Multiple solvent crystal structures (MSCS) is a method where several X-ray crystal structures are solved, each in a unique solvent environment, with organic molecules that serve as probes of the protein surface for sites evolved to bind ligands, while the first hydration shell is essentially maintained. When superimposed, these structures contain a vast amount of information regarding hot spots of protein-protein or protein-ligand interactions, as well as conserved water-binding sites retained with the change in solvent properties. Optimized mining of this information requires reliable structural data and a consistent, objective analysis tool. Detection of related solvent positions (DRoP) was developed to automatically organize and rank the water or small organic molecule binding sites within a given set of structures. It is a flexible tool that can also be used in conserved water analysis given multiple structures of any protein independent of the MSCS method. The DRoP output is an HTML format list of the solvent sites ordered by conservation rank in its population within the set of structures, along with renumbered and recolored PDB files for visualization and facile analysis. Here, we present a previously unpublished set of MSCS structures of bovine pancreatic ribonuclease A (RNase A) and use it together with published structures to illustrate the capabilities of DRoP.
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Proteínas/química , Software , Solventes/química , Animais , Sítios de Ligação , Bovinos , Cristalografia por Raios X , Bases de Dados de Proteínas , Humanos , Ligantes , Modelos Moleculares , Compostos Orgânicos/química , Ligação Proteica , Conformação Proteica , Ribonuclease Pancreático/química , Água/químicaRESUMO
Cytomegalovirus (CMV) is a major cause of infection-related morbidity and mortality in kidney transplantation. The most significant risk for developing CMV infection after transplant depends upon donor (D) and recipient (R) CMV serostatus. In 2012, our Organ Procurement Organization (OPO) began a novel pretransplant CMV prevention strategy via matching deceased kidney donors and recipients by CMV serostatus. Prior to the matching protocol, our distribution of seropositive and seronegative donors and recipients was similar to the United States at large. After the matching protocol, high-risk D+R- were reduced from 18.5% to 2.9%, whereas low-risk D-R- were increased from 13.5% to 24%. There was no adverse effect on transplant rates and no differential effect on waiting times for R+ vs R- after the protocol was implemented. This protocol could be implemented on a regional or national level to optimize low and high-risk CMV seroprofiles and potentially improve CMV-related outcomes in kidney transplantation.
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Infecções por Citomegalovirus , Transplante de Rim , Antivirais/uso terapêutico , Citomegalovirus , Infecções por Citomegalovirus/tratamento farmacológico , Infecções por Citomegalovirus/epidemiologia , Humanos , Rim , Transplante de Rim/efeitos adversos , Doadores de TecidosRESUMO
The present study investigated the neural dynamics of error processing in both the time and frequency domains, as well as associated behavioral phenomena, at the single-trial level. We used a technique that enabled us to separately investigate the evoked and induced aspects of the EEG signal (Cohen & Donner, 2013, Journal of Neurophysiology, 110[12], 2752-2763). We found that at the single-trial level, while the (evoked) error-related negativity (ERN) predicted only post-error slowing (PES)-and only when errors occurred on incongruent trials-induced frontal midline theta power served as a robust predictor of both PES and post-error accuracy (PEA) regardless of stimulus congruency. Mediation models of both electrophysiological indices demonstrated that although the relationship between theta and PEA was mediated by PES, there was not a relationship between the ERN and PEA. Our data suggest that although the ERN and frontal midline theta index functionally related underlying cognitive processes, they are not simply the same process manifested in different domains. In addition, our findings are consistent with the adaptive theory of post-error slowing, as PES was positively associated with post-error accuracy at the single-trial level. More generally, our study provides additional support for the inclusion of a time-frequency approach to better understand the role of medial frontal cortex in action monitoring.
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Potenciais Evocados/fisiologia , Função Executiva/fisiologia , Lobo Frontal/fisiologia , Desempenho Psicomotor/fisiologia , Ritmo Teta/fisiologia , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Fatores de Tempo , Adulto JovemRESUMO
Thrombotic microangiopathy (TMA) is a recognized and serious complication of renal transplantation. Atypical hemolytic uremic syndrome (aHUS), a subset of TMA, occurs in the setting of dysregulation of the alternative complement pathway and can cause disease in native kidneys as well as recurrence in allografts. De novo TMA represents a classification of TMA post-transplant in the absence of clinical or histopathological evidence of TMA or aHUS in the native kidney. De novo TMA is a more heterogeneous syndrome than aHUS and the pathogenesis and risk factors for de novo TMA are poorly understood. The association between calcineurin inhibitors (CNI) and de novo TMA is controversial. Anti-complement blockade therapy with eculizumab is effective in some cases, but more studies are needed to identify appropriate candidates for therapy. We present two cases of de novo TMA occurring immediately in recipients from the same deceased donor and provoking the question of whether deceased donor-related factors could represent risks for developing de novo TMA.
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Transplante de Rim , Rim/patologia , Microangiopatias Trombóticas , Doadores de Tecidos , Síndrome Hemolítico-Urêmica Atípica/diagnóstico , Síndrome Hemolítico-Urêmica Atípica/tratamento farmacológico , Síndrome Hemolítico-Urêmica Atípica/etiologia , Humanos , Transplante de Rim/efeitos adversos , Microangiopatias Trombóticas/etiologia , TransplantadosRESUMO
BACKGROUND AND OBJECTIVE: Nitrous oxide has long been used recreationally for its ability to induce euphoria and other deliriant effects. In modern times, it remains a popular, legal, and widely available option for those seeking altered states. Though substance-induced psychotic symptoms have been mentioned in the literature, the potential long-term negative neuropsychiatric effects related to its use have not been well established. METHODS AND RESULTS: This is a patient case report of a young man (N = 1) who initially presented with acute neurological symptoms requiring hospitalization due to heavy nitrous oxide inhalant use, and went on to present with symptoms concerning for a primary psychotic illness over multiple inpatient admissions. He provided both verbal and written consent to share his story for this case report. DISCUSSION AND CONCLUSIONS: It is important to consider nitrous oxide use as a possible contributing factor to the development of primary psychotic illness. SCIENTIFIC SIGNIFICANCE: Current literature suggests that psychosis associated with nitrous oxide use is transient and resolves upon cessation and treatment of vitamin B12 deficiency. Here, we present a patient with risk factors for psychotic illness developing psychotic illness following extensive nitrous oxide use. This report offers a unique perspective of longitudinal follow-up (often not provided with reports on this topic), and illustrates the importance of healthcare providers inquiring about nitrous oxide abuse in patients presenting with early psychotic symptoms. (Am J Addict 2020;29:525-527).
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Drogas Ilícitas/toxicidade , Óxido Nitroso/toxicidade , Psicoses Induzidas por Substâncias/diagnóstico , Transtornos Relacionados ao Uso de Substâncias/complicações , Humanos , Masculino , Psicoses Induzidas por Substâncias/etiologia , Fatores de Risco , Transtornos Relacionados ao Uso de Substâncias/psicologia , Adulto JovemRESUMO
Boron is an essential plant micronutrient that plays a structural role in the rhamnogalacturonan II component of the pectic cell wall. To prevent boron deficiency under limiting conditions, its uptake, distribution, and homeostasis are mediated by boric acid transporters and channel proteins. Among the membrane channels that facilitate boric acid uptake are the type II nodulin intrinsic protein (NIP) subfamily of aquaporin-like proteins. Arabidopsis (Arabidopsis thaliana) possesses three NIP II genes (NIP5;1, NIP6;1, and NIP7;1) that show distinct tissue expression profiles (predominantly expressed in roots, stem nodes, and developing flowers, respectively). Orthologs of each are represented in all dicots. Here, we show that purified and reconstituted NIP7;1 is a boric acid facilitator. By using native promoter-reporter fusions, we show that NIP7;1 is expressed predominantly in anthers of young flowers in a narrow developmental window, floral stages 9 and 10, with protein accumulation solely within tapetum cells, where it is localized to the plasma membrane. Under limiting boric acid conditions, loss-of-function T-DNA mutants (nip7;1-1 and nip7;1-2) show reduced fertility, including shorter siliques and an increase in aborted seeds, compared with the wild type. Under these conditions, nip7;1 mutant pollen grains show morphological defects, increased aggregation, defective exine cell wall formation, reduced germination frequency, and decreased viability. During stages 9 and 10, the tapetum is essential for supplying materials to the pollen microspore cell wall. We propose that NIP7;1 serves as a gated boric acid channel in developing anthers that aids in the uptake of this critical micronutrient by tapetal cells.
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Aquaporinas/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Ácidos Bóricos/metabolismo , Gametogênese Vegetal/genética , Pólen/genética , Aquaporinas/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Transporte Biológico , Boro/metabolismo , Membrana Celular/metabolismo , Parede Celular/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Modelos Moleculares , Mutação , Filogenia , Pólen/crescimento & desenvolvimento , Pólen/metabolismo , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes de FusãoRESUMO
Iron (Fe) is an essential micronutrient for symbiotic nitrogen fixation in legume nodules, where it is required for the activity of bacterial nitrogenase, plant leghemoglobin, respiratory oxidases, and other Fe proteins in both organisms. Fe solubility and transport within and between plant tissues is facilitated by organic chelators, such as nicotianamine and citrate. We have characterized a nodule-specific citrate transporter of the multidrug and toxic compound extrusion family, MtMATE67 of Medicago truncatula The MtMATE67 gene was induced early during nodule development and expressed primarily in the invasion zone of mature nodules. The MtMATE67 protein was localized to the plasma membrane of nodule cells and also the symbiosome membrane surrounding bacteroids in infected cells. In oocytes, MtMATE67 transported citrate out of cells in an Fe-activated manner. Loss of MtMATE67 gene function resulted in accumulation of Fe in the apoplasm of nodule cells and a substantial decrease in symbiotic nitrogen fixation and plant growth. Taken together, the results point to a primary role of MtMATE67 in citrate efflux from nodule cells in response to an Fe signal. This efflux is necessary to ensure Fe(III) solubility and mobility in the apoplasm and uptake into nodule cells. Likewise, MtMATE67-mediated citrate transport into the symbiosome space would increase the solubility and availability of Fe(III) for rhizobial bacteroids.
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Ferro/metabolismo , Medicago truncatula/fisiologia , Fixação de Nitrogênio/fisiologia , Proteínas de Plantas/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Citratos/metabolismo , Regulação da Expressão Gênica de Plantas , Ferro/farmacocinética , Medicago truncatula/microbiologia , Mutação , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Nódulos Radiculares de Plantas/crescimento & desenvolvimento , Nódulos Radiculares de Plantas/metabolismo , Nódulos Radiculares de Plantas/microbiologia , Simbiose/fisiologiaRESUMO
Studies investigating the functional organization of the medial temporal lobe (MTL) suggest that parahippocampal cortex (PHC) generates representations of spatial and contextual information used by the hippocampus in the formation of episodic memories. However, evidence from animal studies also implicates PHC in spatial binding of visual information held in short term, working memory. Here we examined a 46-year-old man (P.J.), after he had recovered from bilateral medial occipitotemporal cortex strokes resulting in ischemic lesions of PHC and hippocampal atrophy, and a group of age-matched healthy controls. When recalling the color of 1 of 2 objects, P.J. misidentified the target when cued by its location, but not shape. When recalling the position of 1 of 3 objects, he frequently misidentified the target, which was cued by its color. Increasing the duration of the memory delay had no impact on the proportion of binding errors, but did significantly worsen recall precision in both P.J. and controls. We conclude that PHC may play a crucial role in spatial binding during encoding of visual information in working memory.