Effect of different chemical and mechanical defolation methods on the skin quality of potatoes

Without foliage destruction an efficient harvest is impossible. Potatoes for the fresh market are often harvested when the foliage is still heavy green due to tuber size and starch content that must be limited. Tubers from immature vines are typically very susceptible to skinning and mechanical injury during harvest. Young tubers from immature vines need more time after foliage destruction to set periderm than tubers from senescent vines where the formation of periderm is already started. Spray schemes based on metoxuron, carfentrazone-ethyl and diquat at a dose of 300 g/ha caused slower leaf and stem desiccation. Over the 3 growing seasons it could be concluded that mechanical foliage destruction in combination with carfentrazone-ethyl + mineral oil promoted periderm formation better than the other desiccation schemes tested. A split treatment with diquat at 300 g/ha or carfentrazone-ehtyl + mineral oil followed by a second application of diquat or carfentrazone-ethyl can led to a slower periderm formation and even give secondary growth. A double treatment of diquat (300 g/ha) or carfentrazone-ethyl + mineral oil followed by diquat (600 g/ha) after 3 days gave satisfactory results. Rhizoctonia tuber infection increased with a longer field period after treatment. In general the increase was more pronounced for the spray schemes where skin set of the tubers was less fast.     

Rhizobium infection: lessons from the versatile nodulation behaviour of water-tolerant legumes

Water-tolerant legumes provide bacteria with special ways of invading roots to establish N(2)-fixing symbiosis upon flooding. On well-aerated roots, root hair curling (RHC) invasion is used, whereas, under hydroponic conditions, rhizobia enter the cortex through cracks at lateral root bases (LRBs). Here, we compare the physiological and anatomical traits of these invasions. During waterlogging, accumulating ethylene inhibits the epidermal stages of RHC invasion. LRB invasion circumvents this step by direct colonization of the cortical tissue. By avoiding the epidermis for bacterial entry under hydroponic conditions, the stringent nodulation (Nod) factor perception systems that are active within the epidermis are not needed. Consequently, LRB invasion might be useful for analysing the requirement for Nod factor perception and other signal transduction systems downstream of the epidermis.     

14-3-3 checkpoint regulatory proteins interact specifically with DNA repair protein human exonuclease 1 (hEXO1) via a semi-conserved motif

Human exonuclease 1 (hEXO1) acts directly in diverse DNA processing events, including replication, mismatch repair (MMR), and double strand break repair (DSBR), and it was also recently described to function as damage sensor and apoptosis inducer following DNA damage. In contrast, 14-3-3 proteins are regulatory phosphorserine/threonine binding proteins involved in the control of diverse cellular events, including cell cycle checkpoint and apoptosis signaling. hEXO1 is regulated by post-translation Ser/Thr phosphorylation in a yet not fully clarified manner, but evidently three phosphorylation sites are specifically induced by replication inhibition leading to protein ubiquitination and degradation. We demonstrate direct and robust interaction between hEXO1 and six of the seven 14-3-3 isoforms in vitro, suggestive of a novel protein interaction network between DNA repair and cell cycle control. Binding experiments reveal weak affinity of the more selective isoform 14-3-3σ but both 14-3-3 isoforms η and σ significantly stimulate hEXO1 activity, indicating that these regulatory proteins exert a common regulation mode on hEXO1. Results demonstrate that binding involves the phosphorable amino acid S746 in hEXO1 and most likely a second unidentified binding motif. 14-3-3 associations do not appear to directly influence hEXO1 in vitro nuclease activity or in vitro DNA replication initiation. Moreover, specific phosphorylation variants, including hEXO1 S746A, are efficiently imported to the nucleus; to associate with PCNA in distinct replication foci and respond to DNA double strand breaks (DSBs), indicating that 14-3-3 binding does not involve regulating the subcellular distribution of hEXO1. Altogether, these results suggest that association may be related to regulation of hEXO1 availability during the DNA damage response to plausibly prevent extensive DNA resection at the damage site, as supported by recent studies.     

Investigating the ecology and evolution of cryptic marine nematode species through quantitative real-time PCR of the ribosomal ITS region

The presence of morphologically similar but genetically distinct species has impacted biogeographical and ecological paradigms. In marine sediments, free‐living nematodes form one of the most abundant and diverse faunal groups. Inferring the importance of nematode diversity for ecosystem functioning requires species‐level identification, which is hampered by the lack of easily observable diagnostic characters and the presence of cryptic species. New techniques are urgently needed to adequately study the ecology and evolution of cryptic species. The aim of the present study was to evaluate the potential of a quantitative real‐time PCR (qPCR) assay using the internal transcribed spacer (ITS) region of the ribosomal DNA to detect and quantify cryptic species of the R. (P.) marina complex. All primer pairs proved to be highly specific, and each primer pair was able to detect a single juvenile in a pool of 100 nematodes. C_t values were significantly different between developmental stages for all species except for PmIII. Despite differences between developmental stages, a strong correlation was observed between the amount of extracted DNA and the number of nematodes present. Relative and absolute quantification estimates were comparable and resulted in strong positive correlations between the qPCR estimate and the actual number of nematodes present in the samples. The qPCR assay developed here provides the ability to quickly identify and quantify cryptic nematode species and will facilitate their study in laboratory and field settings.     

Cytokine and CXC chemokine expression patterns in aqueous humor of patients with presumed tuberculous uveitis

Aqueous humor (AH) samples from 14 patients with presumed tuberculous uveitis (PTU), and 30 control patients were assayed for the proinflammatory cytokines interleukin IL-4, IL-12, IL-15, IL-17, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, the immunosuppressive cytokine IL-10, and the chemokines GRO-α/CXCL1, IL-8/CXCL8, MIG/CXCL9, IP-10/CXCL10 and SDF-1/CXCL12 with the use of a multiplex assay. Among cytokines, IL-4 and IL-12 were not detected. IL-15, IL-17, IFN-γ, TNF-α and IL-10 levels in AH were significantly higher in patients than in controls (p<0.001; p=0.004; p<0.001; p<0.001; p<0.001, respectively). Among chemokines, SDF-1 levels did not differ significantly between patients and controls, whereas GRO-α, IL-8, MIG and IP-10 levels were significantly higher in patients than in controls (p=0.001; p<0.001; p<0.001; p<0.001, respectively). Mean GRO-α levels in AH of PTU patients were 6-fold higher than IL-8 levels and mean IP-10 levels were 15-fold higher than MIG levels. Clinical disease activity correlated significantly with the levels of IL-15, IFN-γ, TNF-α and IP-10. Logistic regression analysis demonstrated a significant positive association between PTU and high levels of IFN-γ, IL-8, MIG and IP-10. These data suggest that both T helper (Th) Th(1) and Th(17) cells are involved in PTU and that the cytokine profile is polarized toward a Th(1) response. GRO-α and IP-10 might be involved in neutrophil and activated T lymphocyte chemoattraction in PTU, respectively.     

Intravenous and intradermal TriMix-dendritic cell therapy results in a broad T-cell response and durable tumor response in a chemorefractory stage IV-M1c melanoma patient

Dendritic cells (DCs) electroporated with mRNA encoding CD70, CD40L and a constitutively active toll-like receptor 4 (TriMix-DC) have an increased T-cell stimulatory capacity. In a prospective phase IB clinical trial, we treated melanoma patients with intradermal and intravenous injections of autologous TriMix-DC co-electroporated with mRNA encoding full-length MAGE-A3, MAGE-C2, tyrosinase and gp100. We report here the immunological and clinical results obtained in one patient with a particularly favorable outcome. This patient had stage IV-M1c melanoma with documented progression during dacarbazine chemotherapy and received 5 TriMix-DC injections. Following DC therapy, a broad CD8(+) T-cell response against multiple epitopes derived from all four treatment antigens was found in the blood and among T cells derived from DTH biopsy. In addition, CD4(+) T cells recognizing different MAGE-A3-derived epitopes were detected in DTH-derived cells. A spontaneous anti-MAGE-C2 CD8(+) T-cell response was present prior to TriMix-DC therapy and increased during treatment. The tumor response was assessed with 18-fluorodeoxyglucose-positron emission/computed tomography. We documented a partial tumor response according to RECIST criteria with a marked reduction in (18)F-FDG-uptake by lung, lymph node and bone metastases. The patient remains free from progression after 12 months of follow-up. This case report indicates that administration of autologous TriMix-DC by the combined intradermal and intravenous route can mediate a durable objective tumor response accompanied by a broad T-cell response in a chemorefractory stage IV-M1c melanoma patient.     

Primary Cultures of Astrocytes: Their Value in Understanding Astrocytes in Health and Disease

Neurochemical Research - During the past few decades of astrocyte research it has become increasingly clear that astrocytes have taken a central position in all central nervous system activities....     

Multiple substitutions of methionine 129 in human prion protein reveal its importance in the amyloid fibrillation pathway

The role of the polymorphism Met or Val in position 129 in the human prion protein is well documented regarding disease susceptibility and clinical manifestations. However, little is known about the molecular background to this phenomenon. We investigated herein the conformational stability, amyloid fibrillation kinetics, and seeding propensity of different 129 mutants, located in β-strand 1 of PrP (Met(129) (WT), M129A, M129V, M129L, M129W, M129P, M129E, M129K, and M129C) in HuPrP(90-231). The mutations M129V, M129L, M129K, and M129C did not affect stability (midpoints of thermal denaturation, T(m) = 65-66 °C), whereas the mutants M129A and M129E and the largest side chain M129W were destabilized by 3-4 °C. The most destabilizing substitution was M129P, which lowered the T(m) by 7.2 °C. All mutants, except for M129C, formed amyloid-like fibrils within hours during fibril formation under near physiological conditions. Fibril-forming mutants showed a sigmoidal kinetic profile and showed shorter lag times during seeding with preformed amyloid fibrils implicating a nucleated polymerization reaction. In the spontaneous reactions, the lag time of fibril formation was rather uniform for the mutants M129A, M129V, and M129L resembling the wild type. When the substituted amino acid had a distinct feature discriminating it from the wild type, such as size (M129W), charge (M129E, M129K), or rotational constraint (M129P), the fibrillation was impeded. M129C did not form ThT/Congo red-positive fibrils, and non-reducing SDS-PAGE of M129C during fibrillation conditions at different time points revealed covalent dimer formation already 15 min after fibrillation reaction initiation. Position 129 appears to be a key site for dictating PrP receptiveness toward recruitment into the amyloid state.