SlCRCa is a key D-class gene controlling ovule fate determination in tomato.

Cell fate determination and primordium initiation on the placental surface are two key events for ovule formation in seed plants, which directly affect ovule density and seed yield. Despite ovules form in the marginal meristematic tissues of the carpels, angiosperm carpels evolved after the ovules. It is not clear how the development of the ovules and carpels is coordinated in angiosperms. In this study, we identify the S. lycopersicum CRABS CLAW (CRC) homologue SlCRCa as an essential determinant of ovule fate. We find that SlCRCa is not only expressed in the placental surface and ovule primordia but also functions as a D-class gene to block carpel fate and promote ovule fate in the placental surface. Loss of function of SlCRCa causes homeotic transformation of the ovules to carpels. In addition, we find low levels of the S. lycopersicum AINTEGUMENTA (ANT) homologue (SlANT2) favour the ovule initiation, whereas high levels of SlANT2 promote placental carpelization. SlCRCa forms heterodimer with tomato INNER NO OUTER (INO) and AGAMOUS (AG) orthologues, SlINO and TOMATO AGAMOUS1 (TAG1), to repress SlANT2 expression during the ovule initiation. Our study confirms that angiosperm basal ovule cells indeed retain certain carpel properties and provides mechanistic insights into the ovule initiation.

Heat stress impairs floral meristem termination and fruit development by affecting the BR-SlCRCa cascade in tomato.

Floral meristem termination is a key step leading to carpel initiation and fruit development. The frequent occurrence of heat stress due to global warming often disrupts floral determinacy, resulting in defective fruit formation. However, the detailed mechanism behind this phenomenon is largely unknown. Here, we identify CRABS CLAW a (SlCRCa) as a key regulator of floral meristem termination in tomato. SlCRCa functions as an indispensable floral meristem terminator by suppressing SlWUS activity through the TOMATO AGAMOUS 1 (TAG1)-KNUCKLES (SlKNU)-INHIBITOR OF MERISTEM ACTIVITY (SlIMA) network. A direct binding assay revealed that SlCRCa specifically binds to the promoter and second intron of WUSCHEL (SlWUS). We also demonstrate that SlCRCa expression depends on brassinosteroid homeostasis in the floral meristem, which is repressed by heat stress via the circadian factor EARLY FLOWERING 3 (SlELF3). These results provide new insights into floral meristem termination and the heat stress response in flowers and fruits of tomato and suggest that SlCRCa provides a platform for multiple protein interactions that may epigenetically abrogate stem cell activity at the transition from floral meristem to carpel initiation.

Cold stress induces malformed tomato fruits by breaking the feedback loops of stem cell regulation in floral meristem.

Fruit malformation is a major constrain in fruit production worldwide resulting in substantial economic losses. The farmers for decades noticed that the chilling temperature before blooming often caused malformed fruits. However, the molecular mechanism underlying this phenomenon is unclear. Here we examined the fruit development in response to cold stress in tomato, and demonstrated that short-term cold stress increased the callose accumulation in both shoot apical and floral meristems, resulting in the symplastic isolation and altered intercellular movement of WUS. In contrast to the rapidly restored SlWUS transcription during the recovery from cold stress, the callose removal was delayed due to obstructed plasmodesmata. The delayed reinstatement of cell-to-cell transport of SlWUS prevented the activation of SlCLV3 and TAG1, causing the interrupted feedback inhibition of SlWUS expression, leading to the expanded stem cell population and malformed fruits. We further showed that the callose dynamics in response to short-term cold stress presumably exploits the mechanism of bud dormancy during the seasonal growth, involving two antagonistic hormones, abscisic acid and gibberellin. Our results provide a novel insight into the cold stress regulated malformation of fruit.

Actin isovariant ACT7 controls root meristem development in Arabidopsis through modulating auxin and ethylene responses.

The meristem is the most functionally dynamic part in a plant. The shaping of the meristem requires constant cell division and elongation, which are influenced by hormones and the cytoskeletal component, actin. Although the roles of hormones in modulating meristem development have been extensively studied, the role of actin in this process is still elusive. Using the single and double mutants of the vegetative class actin, we demonstrate that actin isovariant ACT7 plays an important role in root meristem development. In the absence of ACT7, but not ACT8 and ACT2, depolymerization of actin was observed. Consistently, the act7 mutant showed reduced cell division, cell elongation, and meristem length. Intracellular distribution and trafficking of auxin transport proteins in the actin mutants revealed that ACT7 specifically functions in the root meristem to facilitate the trafficking of auxin efflux carriers PIN1 and PIN2, and consequently the transport of auxin. Compared with act7, the act7act8 double mutant exhibited slightly enhanced phenotypic response and altered intracellular trafficking. The altered distribution of auxin in act7 and act7act8 affects the response of the roots to ethylene, but not to cytokinin. Collectively, our results suggest that ACT7-dependent auxin-ethylene response plays a key role in controlling Arabidopsis root meristem development.

Cellular Protein Trafficking: A New Player in Low-Temperature Response Pathway.

Unlike animals, plants are unable to escape unfavorable conditions, such as extremities of temperature. Among abiotic variables, the temperature is notableas it affects plants from the molecular to the organismal level. Because of global warming, understanding temperature effects on plants is salient today and should be focused not only on rising temperature but also greater variability in temperature that is now besetting the world's natural and agricultural ecosystems. Among the temperature stresses, low-temperature stress is one of the major stresses that limits crop productivity worldwide. Over the years, although substantial progress has been made in understanding low-temperature response mechanisms in plants, the research is more focused on aerial parts of the plants rather than on the root or whole plant, and more efforts have been made in identifying and testing the major regulators of this pathway preferably in the model organism rather than in crop plants. For the low-temperature stress response mechanism, ICE-CBF regulatory pathway turned out to be the solely established pathway, and historically most of the low-temperature research is focused on this single pathway instead of exploring other alternative regulators. In this review, we tried to take an in-depth look at our current understanding of low temperature-mediated plant growth response mechanism and present the recent advancement in cell biological studies that have opened a new horizon for finding promising and potential alternative regulators of the cold stress response pathway.

Suicidality in Bangladeshi Young Adults During the COVID-19 Pandemic: The Role of Behavioral Factors, COVID-19 Risk and Fear, and Mental Health Problems.

BACKGROUND: It is said that psychological stressors have risen during the COVID-19 pandemic, which may contribute to suicidality. A few studies were conducted investigating suicidality amid the first wave of the pandemic in Bangladesh, but none of these studies explored the predictive role of the suicidality-related factors (eg, behavior and health-related variables, COVID-19 risk, fear of COVID-19). Thus, this study aimed to investigate the prevalence of suicidality and the predictive models explaining suicidality variance among Bangladeshi young adults during the second wave of the pandemic. METHODS: An online-based cross-sectional survey was conducted during the second wave of the pandemic (between 1 and 13 April 2021; a year after the pandemic's inception in the country). The survey questionnaire collected information on socio-demographics, behavior and health-related variables, COVID-19 risk, fear of COVID-19, depression, anxiety, and suicidality. A total of 756 data were analyzed (male 59%; mean age 22.24 ±4.39 years), and hierarchical regression was performed considering suicidality as the dependent variable. A p-value <0.05 was set to be statistically significant with a 95% of confidence interval. RESULTS: About 8.2% reported having at least suicidal thoughts within the pandemic inception to survey time (one-year suicidal ideation). More specifically, 7.40% had only suicidal ideation, whereas 0.10% planned for suicide, 0.70% attempted suicide. None of the socio-demographic variables was significantly associated with suicidality. Taking drugs, performing less physical activity, poor self-reporting health condition, being comorbid, being at higher COVID-19 risk, having fear of COVID-19 infection, and suffering from depression and anxiety were significantly associated with a higher risk of suicidality. However, the final model including all of the studied variables explained a 17.1% (F=8.245, p<0.001) variance in terms of suicidality. CONCLUSION: Although this study reported a lower severity of suicidality than prior Bangladeshi studies conducted during the first wave of the pandemic, a portion of people are still at risk of suicide and they should be given attention.

Insomnia in Bangladeshi Young Adults During the COVID-19 Pandemic: The Role of Behavioral Factors, COVID-19 Risk and Fear, and Mental Health Issues.

BACKGROUND: Given the importance of sleep, several studies were conducted during the first wave of the COVID-19 pandemic in Bangladesh, but no study was conducted during the second wave. Thus, this study assessed the prevalence rate, associated factors, and predictive models of insomnia during the second wave of the COVID-19 pandemic. METHODS: An online-based cross-sectional survey was conducted during the second wave of the pandemic (within April 1-13, 2021) and collected information on sociodemographic, behavior and health, COVID-19 risk, fear of COVID-19, depression, anxiety, suicidality, and insomnia. A total of 756 data from Bangladeshi young adults (22.24 ± 4.39 years) were finally analyzed. RESULTS: About 13% of the participants (n = 98 out of a total of 756) had the symptoms of insomnia. Insomnia had a significant gender difference, where females were more prone to be insomniac. Besides, middle class, urban residence, smoking status, not engaging in physical exercise, poor health status, and multi-comorbidities were also profoundly associated with insomnia. In addition, fear of COVID-19, COVID-19 risk, and mental health problems (i.e., depression, anxiety, and suicidality) showed a significant relationship in terms of insomnia. A total of 31.2% variance predicting insomnia was identified considering all of the studied variables. CONCLUSIONS: The prevalence of insomnia reported herein seems relatively lower than the prior studies, but this figure is not neglectable. Thus, the identified associated factors are highly suggested to consider in policy actions with a special focus on mental health problems to elevate the risk of sleep problems.

Actin Isovariant ACT7 Modulates Root Thermomorphogenesis by Altering Intracellular Auxin Homeostasis.

High temperature stress is one of the most threatening abiotic stresses for plants limiting the crop productivity world-wide. Altered developmental responses of plants to moderate-high temperature has been shown to be linked to the intracellular auxin homeostasis regulated by both auxin biosynthesis and transport. Trafficking of the auxin carrier proteins plays a major role in maintaining the cellular auxin homeostasis. The intracellular trafficking largely relies on the cytoskeletal component, actin, which provides track for vesicle movement. Different classes of actin and the isovariants function in regulating various stages of plant development. Although high temperature alters the intracellular trafficking, the role of actin in this process remains obscure. Using isovariant specific vegetative class actin mutants, here we demonstrate that ACTIN 7 (ACT7) isovariant plays an important role in regulating the moderate-high temperature response in Arabidopsis root. Loss of ACT7, but not ACT8 resulted in increased inhibition of root elongation under prolonged moderate-high temperature. Consistently, kinematic analysis revealed a drastic reduction in cell production rate and cell elongation in act7-4 mutant under high temperature. Quantification of actin dynamicity reveals that prolonged moderate-high temperature modulates bundling along with orientation and parallelness of filamentous actin in act7-4 mutant. The hypersensitive response of act7-4 mutant was found to be linked to the altered intracellular auxin distribution, resulted from the reduced abundance of PIN-FORMED PIN1 and PIN2 efflux carriers. Collectively, these results suggest that vegetative class actin isovariant, ACT7 modulates the long-term moderate-high temperature response in Arabidopsis root.

Reduced Claudin-12 Expression Predicts Poor Prognosis in Cervical Cancer.

BACKGROUND: Within the claudin (CLDN) family, CLDN12 mRNA expression is altered in various types of cancer, but its clinicopathological relevance has yet to be established due to the absence of specific antibodies (Abs) with broad applications. METHODS: We generated a monoclonal Ab (mAb) against human/mouse CLDN12 and verified its specificity. By performing immunohistochemical staining and semiquantification, we evaluated the relationship between CLDN12 expression and clinicopathological parameters in tissues from 138 cases of cervical cancer. RESULTS: Western blot and immunohistochemical analyses revealed that the established mAb selectively recognized the CLDN12 protein. Twenty six of the 138 cases (18.8%) showed low CLDN12 expression, and the disease-specific survival (DSS) and recurrence-free survival rates were significantly decreased compared with those in the high CLDN12 expression group. We also demonstrated, via univariable and multivariable analyses, that the low CLDN12 expression represents a significant prognostic factor for the DSS of cervical cancer patients (HR 3.412, p = 0.002 and HR 2.615, p = 0.029, respectively). CONCLUSIONS: It can be concluded that a reduced CLDN12 expression predicts a poor outcome for cervical cancer. The novel anti-CLDN12 mAb could be a valuable tool to evaluate the biological relevance of the CLDN12 expression in diverse cancer types and other diseases.

ATP binding cassette proteins ABCG37 and ABCG33 function as potassium-independent cesium uptake carriers in Arabidopsis roots.

Radiocesium accumulated in the soil by nuclear accidents is a major environmental concern. The transport process of cesium (Cs+) is tightly linked to the indispensable plant nutrient potassium (K+) as they both belong to the group I alkali metals with similar chemical properties. Most of the transporters that had been characterized to date as Cs+ transporters are directly or indirectly linked to K+. Using a combinatorial approach of physiology, genetics, cell biology, and root uptake assay, here we identified two ATP-binding cassette (ABC) proteins, ABCG37 and ABCG33, as facilitators of Cs+ influx. A gain-of-function mutant of ABCG37 (abcg37-1) showed increased sensitivity to Cs+-induced root growth inhibition, while the double knockout mutant of ABCG33 and ABCG37 (abcg33-1abcg37-2) showed resistance, whereas the single loss-of-function mutants of ABCG33 and ABCG37 did not show any alteration in Cs+ response. In planta short-term radioactive Cs+-uptake assay along with growth and uptake assays in a heterologous system confirmed ABCG33 and ABCG37 as Cs+-uptake carriers. Potassium response and content were unaffected in the double-mutant background and yeast cells lacking potassium-uptake carriers transformed with ABCG33 and ABCG37 failed to grow in the absence of K+, confirming that Cs+ uptake by ABCG33 and ABCG37 is independent of K+. Collectively, this work identified two ABC proteins as new Cs+-influx carriers that act redundantly and independent of the K+-uptake pathway.

Dissecting the Roles of Cuticular Wax in Plant Resistance to Shoot Dehydration and Low-Temperature Stress in Arabidopsis.

Cuticular waxes are a mixture of hydrophobic very-long-chain fatty acids and their derivatives accumulated in the plant cuticle. Most studies define the role of cuticular wax largely based on reducing nonstomatal water loss. The present study investigated the role of cuticular wax in reducing both low-temperature and dehydration stress in plants using Arabidopsis thaliana mutants and transgenic genotypes altered in the formation of cuticular wax. cer3-6, a known Arabidopsis wax-deficient mutant (with distinct reduction in aldehydes, n-alkanes, secondary n-alcohols, and ketones compared to wild type (WT)), was most sensitive to water loss, while dewax, a known wax overproducer (greater alkanes and ketones compared to WT), was more resistant to dehydration compared to WT. Furthermore, cold-acclimated cer3-6 froze at warmer temperatures, while cold-acclimated dewax displayed freezing exotherms at colder temperatures compared to WT. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis identified a characteristic decrease in the accumulation of certain waxes (e.g., alkanes, alcohols) in Arabidopsis cuticles under cold acclimation, which was additionally reduced in cer3-6. Conversely, the dewax mutant showed a greater ability to accumulate waxes under cold acclimation. Fourier Transform Infrared Spectroscopy (FTIR) also supported observations in cuticular wax deposition under cold acclimation. Our data indicate cuticular alkane waxes along with alcohols and fatty acids can facilitate avoidance of both ice formation and leaf water loss under dehydration stress and are promising genetic targets of interest.

Aux/IAA14 Regulates microRNA-Mediated Cold Stress Response in Arabidopsis Roots.

The phytohormone auxin and microRNA-mediated regulation of gene expressions are key regulators of plant growth and development at both optimal and under low-temperature stress conditions. However, the mechanistic link between microRNA and auxin in regulating plant cold stress response remains elusive. To better understand the role of microRNA (miR) in the crosstalk between auxin and cold stress responses, we took advantage of the mutants of Arabidopsis thaliana with altered response to auxin transport and signal. Screening of the mutants for root growth recovery after cold stress at 4 °C revealed that the auxin signaling mutant, solitary root 1 (slr1; mutation in Aux/IAA14), shows a hypersensitive response to cold stress. Genome-wide expression analysis of miRs in the wild-type and slr1 mutant roots using next-generation sequencing revealed 180 known and 71 novel cold-responsive microRNAs. Cold stress also increased the abundance of 26-31 nt small RNA population in slr1 compared with wild type. Comparative analysis of microRNA expression shows significant differential expression of 13 known and 7 novel miRs in slr1 at 4 °C compared with wild type. Target gene expression analysis of the members from one potential candidate miR, miR169, revealed the possible involvement of miR169/NF-YA module in the Aux/IAA14-mediated cold stress response. Taken together, these results indicate that SLR/IAA14, a transcriptional repressor of auxin signaling, plays a crucial role in integrating miRs in auxin and cold responses.

Plasma Membrane Aquaporin Members PIPs Act in Concert to Regulate Cold Acclimation and Freezing Tolerance Responses in Arabidopsis thaliana.

Aquaporins play a major role in plant water uptake at both optimal and environmentally stressed conditions. However, the functional specificity of aquaporins under cold remains obscure. To get a better insight to the role of aquaporins in cold acclimation and freezing tolerance, we took an integrated approach of physiology, transcript profiling and cell biology in Arabidopsis thaliana. Cold acclimation resulted in specific upregulation of PIP1;4 and PIP2;5 aquaporin (plasma membrane intrinsic proteins) expression, and immunoblotting analysis confirmed the increase in amount of PIP2;5 protein and total amount of PIPs during cold acclimation, suggesting that PIP2;5 plays a major role in tackling the cold milieu. Although single mutants of pip1;4 and pip2;5 or their double mutant showed no phenotypic changes in freezing tolerance, they were more sensitive in root elongation and cell survival response under freezing stress conditions compared with the wild type. Consistently, a single mutation in either PIP1;4 or PIP2;5 altered the expression of a number of aquaporins both at the transcriptional and translational levels. Collectively, our results suggest that aquaporin members including PIP1;4 and PIP2;5 function in concert to regulate cold acclimation and freezing tolerance responses.

PIN FORMED 2 Modulates the Transport of Arsenite in Arabidopsis thaliana.

Arsenic contamination is a major environmental issue, as it may lead to serious health hazard. The reduced trivalent form of inorganic arsenic, arsenite, is in general more toxic to plants compared with the fully oxidized pentavalent arsenate. The uptake of arsenite in plants has been shown to be mediated through a large subfamily of plant aquaglyceroporins, nodulin 26-like intrinsic proteins (NIPs). However, the efflux mechanisms, as well as the mechanism of arsenite-induced root growth inhibition, remain poorly understood. Using molecular physiology, synchrotron imaging, and root transport assay approaches, we show that the cellular transport of trivalent arsenicals in Arabidopsis thaliana is strongly modulated by PIN FORMED 2 (PIN2) auxin efflux transporter. Root transport assay using radioactive arsenite, X-ray fluorescence imaging (XFI) coupled with X-ray absorption spectroscopy (XAS), and inductively coupled plasma mass spectrometry analysis revealed that pin2 plants accumulate higher concentrations of arsenite in roots compared with the wild-type. At the cellular level, arsenite specifically targets intracellular sorting of PIN2 and thereby alters the cellular auxin homeostasis. Consistently, loss of PIN2 function results in arsenite hypersensitivity in roots. XFI coupled with XAS further revealed that loss of PIN2 function results in specific accumulation of arsenical species, but not the other metals such as iron, zinc, or calcium in the root tip. Collectively, these results suggest that PIN2 likely functions as an arsenite efflux transporter for the distribution of arsenical species in planta.

Clinical Classification and Severity Scoring Systems in Chronic Pancreatitis: A Systematic Review.

INTRODUCTION: Chronic pancreatitis (CP) is characterised by pain, functional deficits, nutritional and mechanical complications. Frequently managed in out-patient settings, the clinical course is unpredictable and requires multi-disciplinary care. There remains substantial variation in management. In contrast to acute pancreatitis, there are no globally accepted classification or severity scores to predict the disease course or compare interventions. We conducted a systematic review to determine the scope and clinical use of existing scoring systems. METHODS: A systematic search was developed with a medical librarian using the Embase, Medline and Cochrane databases. Original articles and conference abstracts describing an original or modified classification or scoring system in CP that stratified patients into clinical and/or severity categories were included. To assess clinical application/validation, studies using all or part of a score as a stratification tool to measure another parameter or outcome were selected. Studies reporting on diagnosis or aetiology only were excluded. Four authors performed the search in independent pairs and conflicts were resolved by a fifth author using CovidenceTM systematic review software. RESULTS: Following screening 6,652 titles and 235 full-text reviews, 48 papers were analysed. Eleven described original scores and 6 described modifications of published scores. Many were comprehensive but limited in capturing the full spectrum of disease. In 31 studies, a score was used to categorise patients to compare or correlate various outcome measures. Exocrine and endocrine dysfunction and pain were included in 6, 5, and 4 scoring systems, respectively. No score included other nutrition parameters, such as bone health, malnutrition, or nutrient deficiency. Only one score has been objectively validated prospectively and independently for monitoring clinical progression and prognosis, but this had been applied to an in-patient population. CONCLUSION: Available systems and scores do not reflect recent advances and guidelines in CP and are not commonly used. A practical clinical classification and scoring system, validated prospectively for prognostication would be useful for the meaningful analysis in observational and interventional studies in CP.

Experimental necrotizing enterocolitis induces neuroinflammation in the neonatal brain.

BACKGROUND: Necrotizing enterocolitis (NEC) is an inflammatory gastrointestinal disease primarily affecting preterm neonates. Neonates with NEC suffer from a degree of neurodevelopmental delay that is not explained by prematurity alone. There is a need to understand the pathogenesis of neurodevelopmental delay in NEC. In this study, we assessed the macroscopic and microscopic changes that occur to brain cell populations in specific brain regions in a neonatal mouse model of NEC. Moreover, we investigated the role of intestinal inflammation as part of the mechanism responsible for the changes observed in the brain of pups with NEC. METHODS: Brains of mice were assessed for gross morphology and cerebral cortex thickness (using histology). Markers for mature neurons, oligodendrocytes, neural progenitor cells, microglia, and astrocytes were used to quantify their cell populations in different regions of the brain. Levels of cell apoptosis in the brain were measured by Western blotting and immunohistochemistry. Endoplasmic reticulum (ER) stress markers and levels of pro-inflammatory cytokines (in the ileum and brain) were measured by RT-qPCR and Western blotting. A Pearson test was used to correlate the levels of cytokines (ELISA) in the brain and ileum and to correlate activated microglia and astrocyte populations to the severity of NEC. RESULTS: NEC pups had smaller brain weights, higher brain-to-body weight ratios, and thinner cortices compared to control pups. NEC pups had increased levels of apoptosis and ER stress. In addition, NEC was associated with a reduction in the number of neurons, oligodendrocytes, and neural progenitors in specific regions of the brain. Levels of pro-inflammatory cytokines and the density of activated microglia and astrocytes were increased in the brain and positively correlated with the increase in the levels pro-inflammatory cytokines in the gut and the severity of NEC damage respectively. CONCLUSIONS: NEC is associated with severe changes in brain morphology, a pro-inflammatory response in the brain that alters cell homeostasis and density of brain cell populations in specific cerebral regions. We show that the severity of neuroinflammation is associated with the severity of NEC. Our findings suggest that early intervention during NEC may reduce the chance of acute neuroinflammation and cerebral damage.

European Paediatric Surgeons' Association Survey on the Management of Pediatric Appendicitis.

AIM: To define patterns in the management of pediatric appendicitis. METHODS: A total of 169 delegates from 42 (24 European) countries completed a validated survey administered at the EUPSA 2017 annual congress. RESULTS: In the work-up of children with suspected acute appendicitis, most surgeons rely on full blood count (92%), C-reactive protein (82%), and abdominal ultrasonography (76%), but rarely on computed tomography scans or magnetic resonance imaging. In suspected simple appendicitis, most surgeons (76%) do not perform appendectomy at night in clinically stable patients and start antibiotic preoperatively (64%), but only 15% offer antibiotic therapy alone (no appendectomy). In suspected perforated appendicitis, 96% start antibiotic preoperatively, and 92% perform an appendectomy. Presence of phlegmon/abscess is the main contraindication to immediate surgery. In case of appendix mass, most responders (75%) favor a conservative approach and perform interval appendectomy always (56%) or in selected cases (38%) between 2 and 6 months from the first episode (81%). Children with large intraperitoneal abscesses are managed by percutaneous drainage (59% responders) and by surgery (37% responders). Laparoscopy is the preferred surgical approach for both simple (89%) and perforated appendicitis (81%). Most surgeons send the appendix for histology (96%) and pus for microbiology, if present (78%). At the end of the operation, 58% irrigate the abdominal cavity only if contaminated using saline solution (93%). In selected cases, 52% leave a drain in situ. CONCLUSION: Some aspects of appendicitis management lack consensus, particularly appendix mass and intraperitoneal abscess. Evidence-based guidelines should be developed, which may help standardize care and improve clinical outcomes.

Cold stress response in Arabidopsis thaliana is mediated by GNOM ARF-GEF.

Endosomal trafficking plays an important role in regulating plant growth and development both at optimal and stressed conditions. Cold stress response in Arabidopsis root is directly linked to inhibition of the endosomal trafficking of auxin efflux carriers. However, the cellular components that link cold stress and the endosomal trafficking remain elusive. By screening available endosomal trafficking mutants against root growth recovery response under cold stress, we identified GNOM, a SEC7 containing ARF-GEF, as a major modulator of cold response. Contrasting response of partial loss of function mutant gnomB4049/emb30-1 and the engineered Brefeldin A (BFA)-resistant GNOM line, both of which contain mutations within SEC7 domain, to cold stress at the whole-plant level highlights the importance of this domain in modulating the cold response pathway of plants. Cold stress selectively and transiently inhibits GNOM expression. The engineered point mutation at 696 amino acid position (Methionine to Leucine) that makes GNOM resistant to BFA in fact results in overexpression of GNOM both at transcriptional and translational levels, and also alters its subcellular localization. Overexpression and altered cellular localization of GNOM were found to be directly linked to conferring striking cold-resistant phenotype in Arabidopsis. Collectively, these results provide a mechanistic link between GNOM, BFA-sensitive GNOM-regulated trafficking and cold stress.

Spatial Expression and Functional Analysis of Casparian Strip Regulatory Genes in Endodermis Reveals the Conserved Mechanism in Tomato.

Casparian strip (CS) is an impregnation of endodermal cell wall, forming an apoplastic diffusion barrier which forces the symplastic and selective transport of nutrients across endodermis. This extracellular structure can be found in the roots of all higher plants and is thought to provide the protection of vascular tissues. In Arabidopsis, a genetic toolbox regulating the formation of Casparian strips has emerged recently. However, Arabidopsis has the stereotypical root which is much simpler than most other plant species. To understand the Casparian strip formation in a more complex root system, we examined CS regulatory pathways in tomato. Our results reveal a spatiotemporally conserved expression pattern of most essential components of CS machinery in tomato. Further functional analyses verify the role of homologous CS genes in the Casparian strip formation in tomato, indicating the functional conservation of CS regulatory cascade in tomato.

Construction of a Functional Casparian Strip in Non-endodermal Lineages Is Orchestrated by Two Parallel Signaling Systems in Arabidopsis thaliana.

The Casparian strip in the root endodermis forms an apoplastic barrier between vascular tissues and outer ground tissues to enforce selective absorption of water and nutrients. Because of its cell-type specificity, the presence of a Casparian strip is used as a marker for a functional endodermis. Here, we examine the minimal regulators required for reprograming non-endodermal cells to build a functional Casparian strip. We demonstrate that the transcription factor SHORT-ROOT (SHR) serves as a master regulator and promotes Casparian strip formation through two independent activities: inducing the expression of essential Casparian strip enzymes via MYB36 and directing the subcellular localization of Casparian strip formation via SCARECROW (SCR). However, this hierarchical signaling cascade still needs SHR-independent small peptides, derived from the stele, to eventually build a functional Casparian strip in non-endodermal cells. Our study provides a synthetic approach to induce Casparian-strip-containing endodermis using a minimal network of regulators and reveals the deployment of both apoplastic and symplastic communication in the promotion of a specific cell fate.