Formation of Complexes at Plasmodesmata for Potyvirus Intercellular Movement Is Mediated by the Viral Protein P3N-PIPO

Intercellular transport of viruses through cytoplasmic connections, termed plasmodesmata (PD), is essential for systemic infection in plants by viruses. Previous genetic and ultrastructural data revealed that the potyvirus cyclindrical inclusion (CI) protein is directly involved in cell-to-cell movement, likely through the formation of conical structures anchored to and extended through PD. In this study, we demonstrate that plasmodesmatal localization of CI in N. benthamiana leaf cells is modulated by the recently discovered potyviral protein, P3N-PIPO, in a CI:P3N-PIPO ratio-dependent manner. We show that P3N-PIPO is a PD-located protein that physically interacts with CI in planta. The early secretory pathway, rather than the actomyosin motility system, is required for the delivery of P3N-PIPO and CI to PD. Moreover, CI mutations that disrupt virus cell-to-cell movement compromise PD-localization capacity. These data suggest that the CI and P3N-PIPO complex coordinates the formation of PD-associated structures that facilitate the intercellular movement of potyviruses in infected plants

Arabidopsis Plasmodesmal Proteome

The multicellular nature of plants requires that cells should communicate in order to coordinate essential functions. This is achieved in part by molecular flux through pores in the cell wall, called plasmodesmata. We describe the proteomic analysis of plasmodesmata purified from the walls of Arabidopsis suspension cells. Isolated plasmodesmata were seen as membrane-rich structures largely devoid of immunoreactive markers for the plasma membrane, endoplasmic reticulum and cytoplasmic components. Using nano-liquid chromatography and an Orbitrap ion-trap tandem mass spectrometer, 1341 proteins were identified. We refer to this list as the plasmodesmata- or PD-proteome. Relative to other cell wall proteomes, the PD-proteome is depleted in wall proteins and enriched for membrane proteins, but still has a significant number (35%) of putative cytoplasmic contaminants, probably reflecting the sensitivity of the proteomic detection system. To validate the PD-proteome we searched for known plasmodesmal proteins and used molecular and cell biological techniques to identify novel putative plasmodesmal proteins from a small subset of candidates. The PD-proteome contained known plasmodesmal proteins and some inferred plasmodesmal proteins, based upon sequence or functional homology with examples identified in different plant systems. Many of these had a membrane association reflecting the membranous nature of isolated structures. Exploiting this connection we analysed a sample of the abundant receptor-like class of membrane proteins and a small random selection of other membrane proteins for their ability to target plasmodesmata as fluorescently-tagged fusion proteins. From 15 candidates we identified three receptor-like kinases, a tetraspanin and a protein of unknown function as novel potential plasmodesmal proteins. Together with published work, these data suggest that the membranous elements in plasmodesmata may be rich in receptor-like functions, and they validate the content of the PD-proteome as a valuable resource for the further uncovering of the structure and function of plasmodesmata as key components in cell-to-cell communication in plants

Advances in research on the use of biochar in soil for remediation: a review

Purpose: Soil contamination mainly from human activities remains a major environmental problem in the contemporary world. Significant work has been undertaken to position biochar as a readily-available material useful for the management of contaminants in various environmental media notably soil. Here, we review the increasing research on the use of biochar in soil for the remediation of some organic and inorganic contaminants.  Materials and methods: Bibliometric analysis was carried out within the past 10 years to determine the increasing trend in research related to biochar in soil for contaminant remediation. Five exemplar contaminants were reviewed in both laboratory and field-based studies. These included two inorganic (i.e., As and Pb) and three organic classes (i.e., sulfamethoxazole, atrazine, and PAHs). The contaminants were selected based on bibliometric data and as representatives of their various contaminant classes. For example, As and Pb are potentially toxic elements (anionic and cationic, respectively), while sulfamethoxazole, atrazine, and PAHs represent antibiotics, herbicides, and hydrocarbons, respectively.  Results and discussion: The interaction between biochar and contaminants in soil is largely driven by biochar precursor material and pyrolysis temperature as well as some characteristics of the contaminants such as octanol-water partition coefficient (KOW) and polarity. The structural and chemical characteristics of biochar in turn determine the major sorption mechanisms and define biochar’s suitability for contaminant sorption. Based on the reviewed literature, a soil treatment plan is suggested to guide the application of biochar in various soil types (paddy soils, brownfield, and mine soils) at different pH levels (4–5.5) and contaminant concentrations ( 50 mg kg−1).  Conclusions: Research on biochar has grown over the years with significant focus on its properties, and how these affect biochar’s ability to immobilize organic and inorganic contaminants in soil. Few of these studies have been field-based. More studies with greater focus on field-based soil remediation are therefore required to fully understand the behavior of biochar under natural circumstances. Other recommendations are made aimed at stimulating future research in areas where significant knowledge gaps exist

Processing Sentinel Nodes: When and How Many?

Abstract Background: Processing multiple sentinel nodes (SN) is expensive and time consuming. The aim of this study was to analyze a series of SNs from node positive breast cancer patients in order to determine their diagnostic value and delineate a working algorithm.Materials and methods: A prospective database of 105 node positive breast cancer patients undergoing a SN biopsy was created. The SN biopsies were performed with Technetium sulfur colloid, blue dye (Isosulfan Blue or Patent Blue) or both. SN were defined as any blue, suspicious node or radioactive nodes up to 10% of the hottest node. Location of the nodes, criteria of SN definition (hot/blue/suspicious), ten second radioactive counts and pathologic status were recorded. A statistical analysis of the diagnostic value of those nodes was performed.Results: Three hundred and seventy five SNs were recorded in the database. The number of nodes per patient ranged from 1 to 15 with a median value of 3. Radioactivity was found in a total of 322 (86%) sentinel nodes and blue dye in a total of 105 (28%) nodes, with 92 (25%) nodes being both hot and blue. Fourty (11%) sentinel nodes were removed for suspicious appearance. One hundred fifty nine (42%) of the 375 sentinel nodes tested positive for disease. Among the 159 positive nodes, 139 (87%) were radioactive, 52 (33%) were blue, and 46 (29%) were both hot and blue. An analysis of the 322 radioactive nodes reveals that the most radioactive node was positive in 74/95 analyzable patients (77.9%). Consideration of the two most intense nodes was sufficient to diagnose nodal disease in an additional 15 patients, representing a significant increase in sensitivity to 93.7%, p<0.001. Examination of all other radioactive nodes diagnosed one more patient only but the increase in sensitivity, to 94.7%, was not significant (p=1.00).Sensitivity and Nodes Required for Diagnostic Tests Based on Hot Sentinel Nodes   Nodes testedDiagnostic testSensitivity1 (95% CI2)Sensitivity1 (95% CI2)p-value3Median (range) per patientTotalAverage4Hottest node74/9577.9% (68.2-85.8%)-1951.0Two hottest nodes89/9593.7% (86.8-97.7%)<0.0012(1-2)701.9All hot nodes90/9594.7% (88.1-98.3%)1.003 (1 to 15)3033.21. Conditional sensitivity in SN-positive women. 2. 95% exact confidence interval. 3. Exact p-value, McNemar's test for a difference relative to the preceding row. 4. Average nodes required per patient.In patients with both radioactive and blue SNs, non radioactive blue nodes did not add significant diagnostic value.Non-radioactive blue nodes did not add significant diagnostic value.    Nodes testedDiagnostic testSensitivity1 (95% CI2)Sensitivity1 (95% CI2)P-value3Median (range) per patientTotalAverage4Hot nodes596/10591.4% (84.4 to 96%)-33223.1Hot or blue nodes98/10593.3% (86.8 to 97.3%)0.5003 (0 to 15)3353.21. Conditional sensitivity in SN-positive women. 2. 95% exact confidence interval. 3. Exact p-value, McNemar's test for a difference relative to the preceding row. 4. Average nodes required per patient. 5. Nine false negatives are comprised of 4 patients with no hot nodes and 5 patients with negative hot nodes.Conclusions: Processing of the two hottest and the suspicious nodes is sufficient for the initial axillary staging. Additional SNs should be processed only in presence of nodal disease. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1007

A retrospective review with long term follow up of 11,400 cases of pure mucinous breast carcinoma

Background: Pure mucinous breast carcinoma (PMBC) is a rare histologic type of mammary neoplasm. It has been associated with a better short-term prognosis than infiltrating ductal carcinoma (IDC) but identical long-term survival curves have been reported. The value of tumor size for TNM staging has been challenged because of the mucin content of the lesions. This study presents a large PMBC series with 20 years follow up as compared to IDC. The relative significance of a variety of common prognostic factors is calculated for this uncommon histology. Materials and methods: A retrospective analysis of all PMBC cases reported in the SEER database between 1973 and 2002 was conducted. Overall survival (OS) and disease specific survival (DSS) were calculated at 5, 10, 15 and 20 years of follow up. Those curves were compared with all the IDC cases reported into the database during the same period. The prognostic significance of gender, race, laterality, age at diagnosis, T and N status, estrogen and progesterone receptors and administration of radiation therapy was calculated by univariate and multivariate analysis. Results: There were 11,422 PMBC patients reported. The median age at diagnosis was 71 years (Range 25-85). Fifty three percent of the tumors were well differentiated, 38% were moderately differentiated and the remaining 9% were poorly differentiated or anaplastic. The majority of the tumors were located in the upper outer quadrant (44%) the other 56% were roughly evenly divided between the upper inner, lower inner, lower outer and central quadrants. Eighty six percent of the patients had only localized disease at the time of surgery without nodal or distant disease while 12% had regional nodal involvement and 2% had distant metastases. The PMBC cases showed a better differentiation with lesions of lesser grade and more frequent ER/PR expression, smaller size and lesser nodal involvement when compared to the IDC cases of the same period. Kaplan Meier survival curves revealed a 5 years. breast cancer specific survival rate of 94%. Although slowly decreasing with time, 10, 15 and 20 years survival were 89%, 85% and 81% respectively compared to 82% (5 year), 72% (10 year), 66% (15 year) and 62% (20 year) for IDC. There were no significant differences in overall survival. Multivariate analysis by Cox regression revealed the nodal status (N) to be the most significant prognostic factor followed by age, tumor size (T), progesterone receptors and nuclear grade. Disease specific survival curves stratified for nodal status revealed a highly significant difference between node negative and node positive patients. The addition of radiation therapy after surgery did not significantly improve overall survival. Conclusions: This large retrospective comparative analysis confirms the less aggressive behavior of PMBC compared to IDC. This favorable outcome is maintained after 20 years. This tumor presents typically in older patients and is rarely associated with nodal disease. Positive Nodal status appears to be the most significant predictor of worse prognosis. \ua9 2007 Springer Science+Business Media, LLC