Rapeseed rotation, compost and biocontrol amendments reduce soilborne diseases and increase tuber yield in organic and conventional potato production systems

Aims

Integrating multiple soil and disease management practices may improve crop productivity and disease control, but potential interactions and limitations need to be determined.

Methods

Three different potential disease-suppressive management practices, including a Brassica napus (rapeseed) green manure rotation crop, conifer-based compost amendment, and three biological control organisms (Trichoderma virens, Bacillus subtilis, and Rhizoctonia solani hypovirulent isolate Rhs1A1) were evaluated alone and in combination at sites with both organic and conventional management histories for their effects on soilborne diseases and tuber yield.

Results

Rapeseed rotation reduced all observed soilborne diseases (stem canker, black scurf, common scab, and silver scurf) by 10 to 52 % in at least one year at both sites. Compost amendment had variable effects on tuber diseases, but consistently increased yield (by 9 to 15 %) at both sites. Biocontrol effects on disease varied, though Rhs1A1 decreased black scurf at the conventional site and T. virens reduced multiple diseases at the organic site in at least one year. Combining rapeseed rotation with compost amendment both reduced disease and increased yield, whereas biocontrol additions produced only marginal additive effects.

Conclusions

Use of these treatments alone, and in combination, can be effective at reducing disease and increasing yield under both conventional and organic production practices.     

Green fluorescent protein (GFP) color reporter gene visualizes parvovirus B19 non-structural segment 1 (NS1) transfected endothelial modification

Background

Human Parvovirus B19 (PVB19) has been associated with myocarditis putative due to endothelial infection. Whether PVB19 infects endothelial cells and causes a modification of endothelial function and inflammation and, thus, disturbance of microcirculation has not been elucidated and could not be visualized so far.

Methods and Findings

To examine the PVB19-induced endothelial modification, we used green fluorescent protein (GFP) color reporter gene in the non-structural segment 1 (NS1) of PVB19. NS1-GFP-PVB19 or GFP plasmid as control were transfected in an endothelial-like cell line (ECV304). The endothelial surface expression of intercellular-adhesion molecule-1 (CD54/ICAM-1) and extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) were evaluated by flow cytometry after NS-1-GFP or control-GFP transfection. To evaluate platelet adhesion on NS-1 transfected ECs, we performed a dynamic adhesion assay (flow chamber). NS-1 transfection causes endothelial activation and enhanced expression of ICAM-1 (CD54: mean±standard deviation: NS1-GFP vs. control-GFP: 85.3±11.2 vs. 61.6±8.1; P<0.05) and induces endothelial expression of EMMPRIN/CD147 (CD147: mean±SEM: NS1-GFP vs. control-GFP: 114±15.3 vs. 80±0.91; P<0.05) compared to control-GFP transfected cells. Dynamic adhesion assays showed that adhesion of platelets is significantly enhanced on NS1 transfected ECs when compared to control-GFP (P<0.05). The transfection of ECs was verified simultaneously through flow cytometry, immunofluorescence microscopy and polymerase chain reaction (PCR) analysis.

Conclusions

GFP color reporter gene shows transfection of ECs and may help to visualize NS1-PVB19 induced endothelial activation and platelet adhesion as well as an enhanced monocyte adhesion directly, providing in vitro evidence of possible microcirculatory dysfunction in PVB19-induced myocarditis and, thus, myocardial tissue damage.     

Adipocytokines and CD34 progenitor cells in Alzheimer's disease

Background

Alzheimer''s disease (AD) and atherosclerosis share common vascular risk factors such as arterial hypertension and hypercholesterolemia. Adipocytokines and CD34⁺ progenitor cells are associated with the progression and prognosis of atherosclerotic diseases. Their role in AD is not adequately elucidated.

Methods and Findings

In the present study, we measured in 41 patients with early AD and 37 age- and weight-matched healthy controls blood concentrations of adiponectin and leptin by enzyme linked immunoabsorbent assay and of CD34⁺ progenitor cells using flow cytometry. We found significantly lower plasma levels of leptin in AD patients compared with the controls, whereas plasma levels of adiponectin did not show any significant differences (AD vs. control (mean±SD): leptin:8.9±5.6 ng/mL vs.16.3±15.5 ng/mL;P = 0.038; adiponectin:18.5±18.1 µg/mL vs.16.7±8.9 µg/mL;P = 0.641). In contrast, circulating CD34⁺ cells were significantly upregulated in AD patients (mean absolute cell count±SD:253±51 vs. 203±37; P = 0.02) and showed an inverse correlation with plasma levels of leptin (r = −0.248; P = 0.037).In logistic regression analysis, decreased leptin concentration (P = 0.021) and increased number of CD34⁺ cells (P = 0.036) were both significantly associated with the presence of AD. According to multifactorial analysis of covariance, leptin serum levels were a significant independent predictor for the number of CD34⁺ cells (P = 0.002).

Conclusions

Our findings suggest that low plasma levels of leptin and increased numbers of CD34⁺ progenitor cells are both associated with AD. In addition, the results of our study provide first evidence that increased leptin plasma levels are associated with a reduced number of CD34⁺ progenitor cells in AD patients. These findings point towards a combined involvement of leptin and CD34⁺ progenitor cells in the pathogenesis of AD. Thus, plasma levels of leptin and circulating CD34⁺ progenitor cells could represent an important molecular link between atherosclerotic diseases and AD. Further studies should clarify the pathophysiological role of both adipocytokines and progenitor cells in AD and possible diagnostic and therapeutic applications.     

Molecular pathways used by platelets to initiate and accelerate atherogenesis

PURPOSE OF REVIEW: The response to injury model in the development of atherosclerosis is broadly accepted by the scientific audience. Platelets are generally not believed to be involved in the initiation of atherosclerosis. New data imply, however, that the response to injury model is too simple for a complete understanding of the inflammatory disease atherosclerosis. The involvement of platelets in the initiation of atherosclerotic lesion formation is critical in directing the atherosclerotic process into regeneration or ongoing vascular injury. RECENT FINDINGS: Platelets internalize oxidized phospholipids and promote foam cell formation. Platelets also recruit circulating blood cells including progenitor cells to the vessel, that are able to differentiate into foam cells or endothelial cells depending on conditions. Platelets express various scavenger receptors that are able to regulate LDL-uptake. LDL-laden platelets are internalized by adherent progenitor cells that in turn differentiate into macrophages and foam cells. SUMMARY: An expanding body of evidence continues to build on the role of platelets as initial actors in the development of atherosclerotic lesions. Platelets bind to leukocytes, endothelial cells, and circulating progenitor cells and initiate monocyte transformation into macrophages. Therefore platelets regulate the initiation, development and total extent of atherosclerotic lesions.     

Mechanism of Genome Expression in a Single-stranded RNA Virus from the Cultivated Mushroom [Agaricus bisporus (Lange) Imbach]

The single-stranded RNA genome of a bacilliform virus from the common cultivated mushroom, Agaricus bisporus, was translated in an in vitro rabbit reticulocyte system. Optimal conditions for translation of mushroom bacilliform virus (MBV) RNA were 2.5 mM Mg²⁺, 70 mM K⁺, pH 7.2, and 60μg/ml RNA. Gel electrophoretic analysis showed that MBV RNA directs the synthesis of two major polypeptides of MW 77,000 and 37,000 and possibly several minor polypeptides (MW 21,000—28,000). An RNA polymerase activity could not be detected in purified virus preparations. The findings support the notion that the MBV genome functions directly as messenger for protein synthesis and further establishes the closer similarity between MBV and viruses of higher plants than mycoviruses.