Auxin paves the way for planar morphogenesis.

The coordinated growth of epidermal cells in plant leaves creates the characteristic jigsaw puzzle appearance of the pavement cells. Now, Xu et al. (2010) report that AUXIN-BINDING PROTEIN 1 mediates auxin activation of two GTPase pathways that antagonistically control planar morphogenesis of leaf epidermal cells to create this distinctive pattern.

[Critical care nurses' decision-making regarding verification of blindly inserted gastric tubes: A cross-sectional questionnaire study]. / Entscheidungsfindung von Intensivpflegefachpersonen zur Verifikation blind applizierter Magensonden.

Critical care nurses' decision-making regarding verification of blindly inserted gastric tubes: A cross-sectional questionnaire study Abstract: Background: The placement and verification of the correct position of blindly applied gastric tubes is regularly performed by nurses in clinical practice. International guidelines recommend a radiological verification as a "first-line" method or if pH measurement is not possible. For Germany, neither evidence-based recommendations nor current data are available. Question: Which methods are used by nurses in German intensive care units for verification of the correct position of blindly applied gastric tubes and how do they assess the reliability of different methods? Methods: Multicenter questionnaire survey. Intensive care units in a non-probability, citeria-based sampling of hospitals in and around Cologne, Germany were included. One nurse was included per participating ward. Analyses were mostly descriptive. Results: In 22 hospitals, 38 wards agreed to participate and 32 (84%) responded to the survey. Auscultation of the upper abdomen with simultaneous air insufflation and aspiration of gastric secretions are frequently used methods for determining the position of gastric tubes. Participants consider auscultation, aspiration of gastric secretions, and radiological control as reliable methods. Conclusions: The findings are in contrast to international recommendations and support the need for evidence-based best practice recommendations and training. Likewise, there is a need for research on feasible bedside methods.

Rho-of-plant activated root hair formation requires Arabidopsis YIP4a/b gene function.

Root hairs are protrusions from root epidermal cells with crucial roles in plant soil interactions. Although much is known about patterning, polarity and tip growth of root hairs, contributions of membrane trafficking to hair initiation remain poorly understood. Here, we demonstrate that the trans-Golgi network-localized YPT-INTERACTING PROTEIN 4a and YPT-INTERACTING PROTEIN 4b (YIP4a/b) contribute to activation and plasma membrane accumulation of Rho-of-plant (ROP) small GTPases during hair initiation, identifying YIP4a/b as central trafficking components in ROP-dependent root hair formation.

Membrane Sterol Composition in Arabidopsis thaliana Affects Root Elongation via Auxin Biosynthesis.

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (ß-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.

Regulating plant physiology with organic electronics.

The organic electronic ion pump (OEIP) provides flow-free and accurate delivery of small signaling compounds at high spatiotemporal resolution. To date, the application of OEIPs has been limited to delivery of nonaromatic molecules to mammalian systems, particularly for neuroscience applications. However, many long-standing questions in plant biology remain unanswered due to a lack of technology that precisely delivers plant hormones, based on cyclic alkanes or aromatic structures, to regulate plant physiology. Here, we report the employment of OEIPs for the delivery of the plant hormone auxin to induce differential concentration gradients and modulate plant physiology. We fabricated OEIP devices based on a synthesized dendritic polyelectrolyte that enables electrophoretic transport of aromatic substances. Delivery of auxin to transgenic Arabidopsis thaliana seedlings in vivo was monitored in real time via dynamic fluorescent auxin-response reporters and induced physiological responses in roots. Our results provide a starting point for technologies enabling direct, rapid, and dynamic electronic interaction with the biochemical regulation systems of plants.

Auxin and ROP GTPase Signaling of Polar Nuclear Migration in Root Epidermal Hair Cells.

Polar nuclear migration is crucial during the development of diverse eukaryotes. In plants, root hair growth requires polar nuclear migration into the outgrowing hair. However, knowledge about the dynamics and the regulatory mechanisms underlying nuclear movements in root epidermal cells remains limited. Here, we show that both auxin and Rho-of-Plant (ROP) signaling modulate polar nuclear position at the inner epidermal plasma membrane domain oriented to the cortical cells during cell elongation as well as subsequent polar nuclear movement to the outer domain into the emerging hair bulge in Arabidopsis (Arabidopsis thaliana). Auxin signaling via the nuclear AUXIN RESPONSE FACTOR7 (ARF7)/ARF19 and INDOLE ACETIC ACID7 pathway ensures correct nuclear placement toward the inner membrane domain. Moreover, precise inner nuclear placement relies on SPIKE1 Rho-GEF, SUPERCENTIPEDE1 Rho-GDI, and ACTIN7 (ACT7) function and to a lesser extent on VTI11 vacuolar SNARE activity. Strikingly, the directionality and/or velocity of outer polar nuclear migration into the hair outgrowth along actin strands also are ACT7 dependent, auxin sensitive, and regulated by ROP signaling. Thus, our findings provide a founding framework revealing auxin and ROP signaling of inner polar nuclear position with some contribution by vacuolar morphology and of actin-dependent outer polar nuclear migration in root epidermal hair cells.

Arabidopsis AIP1-2 restricted by WER-mediated patterning modulates planar polarity.

The coordination of cell polarity within the plane of the tissue layer (planar polarity) is crucial for the development of diverse multicellular organisms. Small Rac/Rho-family GTPases and the actin cytoskeleton contribute to planar polarity formation at sites of polarity establishment in animals and plants. Yet, upstream pathways coordinating planar polarity differ strikingly between kingdoms. In the root of Arabidopsis thaliana, a concentration gradient of the phytohormone auxin coordinates polar recruitment of Rho-of-plant (ROP) to sites of polar epidermal hair initiation. However, little is known about cytoskeletal components and interactions that contribute to this planar polarity or about their relation to the patterning machinery. Here, we show that ACTIN7 (ACT7) represents a main actin isoform required for planar polarity of root hair positioning, interacting with the negative modulator ACTIN-INTERACTING PROTEIN1-2 (AIP1-2). ACT7, AIP1-2 and their genetic interaction are required for coordinated planar polarity of ROP downstream of ethylene signalling. Strikingly, AIP1-2 displays hair cell file-enriched expression, restricted by WEREWOLF (WER)-dependent patterning and modified by ethylene and auxin action. Hence, our findings reveal AIP1-2, expressed under control of the WER-dependent patterning machinery and the ethylene signalling pathway, as a modulator of actin-mediated planar polarity.

Cellulose synthesis during cell plate assembly.

The plant cell wall surrounds and protects the cells. To divide, plant cells must synthesize a new cell wall to separate the two daughter cells. The cell plate is a transient polysaccharide-based compartment that grows between daughter cells and gives rise to the new cell wall. Cellulose constitutes a key component of the cell wall, and mutants with defects in cellulose synthesis commonly share phenotypes with cytokinesis-defective mutants. However, despite the importance of cellulose in the cell plate and the daughter cell wall, many open questions remain regarding the timing and regulation of cellulose synthesis during cell division. These questions represent a critical gap in our knowledge of cell plate assembly, cell division and growth. Here, we review what is known about cellulose synthesis at the cell plate and in the newly formed cross-wall and pose key questions about the molecular mechanisms that govern these processes. We further provide an outlook discussing outstanding questions and possible future directions for this field of research.

A Framework for Lateral Membrane Trafficking and Polar Tethering of the PEN3 ATP-Binding Cassette Transporter.

The outermost cell layer of plants, the epidermis, and its outer (lateral) membrane domain facing the environment are continuously challenged by biotic and abiotic stresses. Therefore, the epidermis and the outer membrane domain provide important selective and protective barriers. However, only a small number of specifically outer membrane-localized proteins are known. Similarly, molecular mechanisms underlying the trafficking and the polar placement of outer membrane domain proteins require further exploration. Here, we demonstrate that ACTIN7 (ACT7) mediates trafficking of the PENETRATION3 (PEN3) outer membrane protein from the trans-Golgi network (TGN) to the plasma membrane in the root epidermis of Arabidopsis (Arabidopsis thaliana) and that actin function contributes to PEN3 endocytic recycling. In contrast to such generic ACT7-dependent trafficking from the TGN, the EXOCYST84b (EXO84b) tethering factor mediates PEN3 outer-membrane polarity. Moreover, precise EXO84b placement at the outer membrane domain itself requires ACT7 function. Hence, our results uncover spatially and mechanistically distinct requirements for ACT7 function during outer lateral membrane cargo trafficking and polarity establishment. They further identify an exocyst tethering complex mediator of outer lateral membrane cargo polarity.

The endoplasmic reticulum is the main membrane source for biogenesis of the lytic vacuole in Arabidopsis.

Vacuoles are multifunctional organelles essential for the sessile lifestyle of plants. Despite their central functions in cell growth, storage, and detoxification, knowledge about mechanisms underlying their biogenesis and associated protein trafficking pathways remains limited. Here, we show that in meristematic cells of the Arabidopsis thaliana root, biogenesis of vacuoles as well as the trafficking of sterols and of two major tonoplast proteins, the vacuolar H(+)-pyrophosphatase and the vacuolar H(+)-adenosinetriphosphatase, occurs independently of endoplasmic reticulum (ER)-Golgi and post-Golgi trafficking. Instead, both pumps are found in provacuoles that structurally resemble autophagosomes but are not formed by the core autophagy machinery. Taken together, our results suggest that vacuole biogenesis and trafficking of tonoplast proteins and lipids can occur directly from the ER independent of Golgi function.

Improvement of pelvic floor-related quality of life and sexual function after vaginal mesh implantation for cystocele: primary endpoint of a prospective multicentre trial.

PURPOSE: Pelvic organ prolapse (POP) impairs quality of life (QoL) due to vaginal bulge symptoms and changes in bladder/bowel and sexual function. The effect of alloplastic meshes on QoL is still being discussed. The purpose of this study was to prospectively evaluate the effect of mesh implantation on QoL and sexual function over 1 year. METHODS: 289 women with cystocele > stage I were included in this prospective multicenter study, with nine hospitals participating (ClinicalTrials.gov NCT01084889). Mesh exposures rates and pelvic floor-related QoL using the validated German version of the p-QoL questionnaire were evaluated as the primary endpoints. Based on a single-sided binominal test with α = 0.05 and a power of 0.80, a sample size of 225 for the mesh exposures was calculated. The mesh used was a 6-arm mesh with titanium coating (TILOOP(®) Total 6, sponsor pfm medical ag, Germany). Preoperative data were compared to 6 and 12 months postoperative data, using Wilcoxon test. RESULTS: The mean age of the patients was 67 years (min 43, max 87). All domains of QoL improved significantly compared after surgery: mean prolapse score dropped from 73.7 to 19.4 after 6 and 16.2 after 12 months (p < 0.001). Sexual function also improved significantly. The rate of dyspareunia was lower at follow-up. CONCLUSIONS: In this prospective trial, a significant positive effect of mesh implantation on pelvic floor-related QoL was observed. These findings remained stable 1 year after surgery with further improvement. This trial adds further data to the ongoing discussion on the role and risk of meshes in POP surgery.

High lipid order of Arabidopsis cell-plate membranes mediated by sterol and DYNAMIN-RELATED PROTEIN1A function.

Membranes of eukaryotic cells contain high lipid-order sterol-rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher-plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell-plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order-sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid-order membrane domain. The cell-plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate, and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell-plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid-order domain, and pave the way to explore potential feedback between lipid order and function of dynamin-related proteins during cytokinesis.

SABRE is required for stabilization of root hair patterning in Arabidopsis thaliana.

Patterned differentiation of distinct cell types is essential for the development of multicellular organisms. The root epidermis of Arabidopsis thaliana is composed of alternating files of root hair and non-hair cells and represents a model system for studying the control of cell-fate acquisition. Epidermal cell fate is regulated by a network of genes that translate positional information from the underlying cortical cell layer into a specific pattern of differentiated cells. While much is known about the genes of this network, new players continue to be discovered. Here we show that the SABRE (SAB) gene, known to mediate microtubule organization, anisotropic cell growth and planar polarity, has an effect on root epidermal hair cell patterning. Loss of SAB function results in ectopic root hair formation and destabilizes the expression of cell fate and differentiation markers in the root epidermis, including expression of the WEREWOLF (WER) and GLABRA2 (GL2) genes. Double mutant analysis reveal that wer and caprice (cpc) mutants, defective in core components of the epidermal patterning pathway, genetically interact with sab. This suggests that SAB may act on epidermal patterning upstream of WER and CPC. Hence, we provide evidence for a role of SAB in root epidermal patterning by affecting cell-fate stabilization. Our work opens the door for future studies addressing SAB-dependent functions of the cytoskeleton during root epidermal patterning.

Vulvar cancer: a review for dermatologists.

Vulvar malignancies are important tumors of the female reproductive system. They represent a serious health issue with an incidence between 2 and 7 per 100,000 and year. We provide a review about most important cancer entities, i.e., melanoma, squamous cell carcinoma, basal cell carcinoma, neuroendocrine cancer, and skin adnexal malignancies.Squamous cell carcinoma is the most common vulvar malignancy that can develop from vulvar intraepithelial neoplasia or de novo. Basal cell carcinoma represents only 2% of all vulvar cancers. Melanoma of the vulva exists in two major types-superficial spreading and acral lentiginous. A special feature is the occurrence of multiple vulvar melanomas. Of the adnexal cancer types Paget's disease and carcinoma are seen more frequently than other adnexal malignancies. The dermatologist should be aware of this problem, since he might be the first to be consulted by patients for vulvar disease. Treatment should be interdisciplinary in close association to gynecologists, oncologists, and radiologists.

Endocytosis restricts Arabidopsis KNOLLE syntaxin to the cell division plane during late cytokinesis.

Cytokinesis represents the final stage of eukaryotic cell division during which the cytoplasm becomes partitioned between daughter cells. The process differs to some extent between animal and plant cells, but proteins of the syntaxin family mediate membrane fusion in the plane of cell division in diverse organisms. How syntaxin localization is kept in check remains elusive. Here, we report that localization of the Arabidopsis KNOLLE syntaxin in the plane of cell division is maintained by sterol-dependent endocytosis involving a clathrin- and DYNAMIN-RELATED PROTEIN1A-dependent mechanism. On genetic or pharmacological interference with endocytosis, KNOLLE mis-localizes to lateral plasma membranes after cell-plate fusion. Fluorescence-loss-in-photo-bleaching and fluorescence-recovery-after-photo-bleaching experiments reveal lateral diffusion of GFP-KNOLLE from the plane of division to lateral membranes. In an endocytosis-defective sterol biosynthesis mutant displaying lateral KNOLLE diffusion, KNOLLE secretory trafficking remains unaffected. Thus, restriction of lateral diffusion by endocytosis may serve to maintain specificity of syntaxin localization during late cytokinesis.

Conserved Arabidopsis ECHIDNA protein mediates trans-Golgi-network trafficking and cell elongation.

Multiple steps of plant growth and development rely on rapid cell elongation during which secretory and endocytic trafficking via the trans-Golgi network (TGN) plays a central role. Here, we identify the ECHIDNA (ECH) protein from Arabidopsis thaliana as a TGN-localized component crucial for TGN function. ECH partially complements loss of budding yeast TVP23 function and a Populus ECH complements the Arabidopsis ech mutant, suggesting functional conservation of the genes. Compared with wild-type, the Arabidopsis ech mutant exhibits severely perturbed cell elongation as well as defects in TGN structure and function, manifested by the reduced association between Golgi bodies and TGN as well as mislocalization of several TGN-localized proteins including vacuolar H(+)-ATPase subunit a1 (VHA-a1). Strikingly, ech is defective in secretory trafficking, whereas endocytosis appears unaffected in the mutant. Some aspects of the ech mutant phenotype can be phenocopied by treatment with a specific inhibitor of vacuolar H(+)-ATPases, concanamycin A, indicating that mislocalization of VHA-a1 may account for part of the defects in ech. Hence, ECH is an evolutionarily conserved component of the TGN with a central role in TGN structure and function.

Beyond Total Mesorectal Excision (TME)-Results of MRI-Guided Multivisceral Resections in T4 Rectal Carcinoma and Local Recurrence.

Rectal cancer invading adjacent organs (T4) and locally recurrent rectal cancer (LRRC) pose a special challenge for surgical resection. We investigate the diagnostic performance of MRI and the results that can be achieved with MRI-guided surgery. All consecutive patients who underwent MRI-based multivisceral resection for T4 rectal adenocarcinoma or LRRC between 2005 and 2019 were included. Pelvic MRI findings were reviewed according to a seven-compartment staging system and correlated with histopathology. Outcomes were investigated by comparing T4 tumors and LRRC with respect to cause-specific survival in uni- and multivariate analysis. We identified 48 patients with T4 tumors and 28 patients with LRRC. Overall, 529 compartments were assessed with an accuracy of 81.7%, a sensitivity of 88.6%, and a specificity of 79.2%. Understaging was as low as 3.0%, whereas overstaging was 15.3%. The median number of resected compartments was 3 (interquartile range 3-4) for T4 tumors and 4 (interquartile range 3-5) for LRRC (p = 0.017). In 93.8% of patients with T4 tumors, a histopathologically complete (R0(local)-) resection could be achieved compared to 57.1% in LRRC (p < 0.001). Five-year overall survival for patients with T4 tumors was 53.3% vs. 32.1% for LRRC (p = 0.085). R0-resection and M0-category emerged as independent prognostic factors, whereas the number of resected compartments was not associated with prognosis in multivariate analysis. MRI predicts compartment involvement with high accuracy and especially avoids understaging. Surgery based on MRI yields excellent loco-regional results for T4 tumors and good results for LRRC. The number of resected compartments is not independently associated with prognosis, but R0-resection remains the crucial surgical factor.

Evidence for a protein transported through the secretory pathway en route to the higher plant chloroplast.

In contrast to animal and fungal cells, green plant cells contain one or multiple chloroplasts, the organelle(s) in which photosynthetic reactions take place. Chloroplasts are believed to have originated from an endosymbiotic event and contain DNA that codes for some of their proteins. Most chloroplast proteins are encoded by the nuclear genome and imported with the help of sorting signals that are intrinsic parts of the polypeptides. Here, we show that a chloroplast-located protein in higher plants takes an alternative route through the secretory pathway, and becomes N-glycosylated before entering the chloroplast.