Phosphorylation-dependent control of an RNA granule-localized protein that fine-tunes defence gene expression at a post-transcriptional level

Mitogen-activated protein kinase (MAPK) cascades are key signalling modules of plant defence responses to pathogen-associated molecular patterns [PAMPs; e.g. the bacterial peptide flagellin (flg22)]. Tandem zinc finger protein 9 (TZF9) is a RNA-binding protein that is phosphorylated by two PAMP-responsive MAPKs, MPK3 and MPK6. We mapped the major phosphosites in TZF9 and showed their importance for controlling in vitro RNA-binding activity, in vivo flg22-induced rapid disappearance of TZF9-labelled processing body-like structures and TZF9 protein turnover. Microarray analysis showed a strong discordance between transcriptome (total mRNA) and translatome (polysome-associated mRNA) in the tzf9 mutant, with more mRNAs associated with ribosomes in the absence of TZF9. This suggests that TZF9 may sequester and inhibit the translation of subsets of mRNAs. Fittingly, TZF9 physically interacts with poly(A)-binding protein 2 (PAB2), a hallmark constituent of stress granules - sites for stress-induced translational stalling/arrest. TZF9 even promotes the assembly of stress granules in the absence of stress. Hence, MAPKs may control defence gene expression post-transcriptionally through release from translation arrest within TZF9-PAB2-containing RNA granules or by perturbing the function of PAB2 in translation control (e.g. in the mRNA closed-loop model of translation).

Synthesis of Lactam-Bridged and Lipidated Cyclo-Peptides as Promising Anti-Phytopathogenic Agents

Antimicrobial resistance to conventional antibiotics and the limited alternatives to combat plant-threatening pathogens are worldwide problems. Antibiotic lipopeptides exert remarkable membrane activity, which usually is not prone to fast resistance formation, and often show organism-type selectivity. Additional modes of action commonly complement the bioactivity profiles of such compounds. The present work describes a multicomponent-based methodology for the synthesis of cyclic polycationic lipopeptides with stabilized helical structures. The protocol comprises an on solid support Ugi-4-component macrocyclization in the presence of a lipidic isocyanide. Circular dichroism was employed to study the influence of both macrocyclization and lipidation on the amphiphilic helical structure in water and micellar media. First bioactivity studies against model phytopathogens demonstrated a positive effect of the lipidation on the antimicrobial activity.

Tumor characteristics involved in the metastatic behaviour as an improvement in primary cutaneous melanoma prognostics

We report the results of a retrospective immunohistochemical study on routinely fixed, paraffin embedded tissues from 147 primary cutaneous melanomas belonging to the classes pT3 and pT4, the development of which has been followed for at least five years. The parameters Cathepsin B, Cathepsin D, Collagenase IV, Metallothionein and PCNA were selected from previous studies on small collectives. All parameters showed statistically significant differences between tumors of the metastatic and the nonmetastatic group. Particularly conspicuous was the expression of Cathepsin B, Cathepsin D and Collagenase IV at the dermal invading front of the tumors. Based on this data we present a procedure of combining these data with established clinical-histological parameters such as tumor thickness and ulceration to an integrated individual risk factor that improves the certainty of melanoma prognosis.

Family influence in the recruitment of schizophrenic research subjects

While seeking research subjects to test the effect of hemodialysis on schizophrenia, the authors noted that the relatives of schizophrenic patients tried to involve themselves excessively in the selection process. Of 27 patients referrals meeting diagnostic criteria for schizophrenia, only one contact was initiated by the patient; the rest were initiated by family members. In more than half of the family-initiated contacts relatives attempted to become excessively involved in the patient's decision making. The authors discuss these observations in light of family theories of schizophrenia. They urge caution in selecting subjects for research that attempts to test other researchers' earlier claims which may have stimulated premature hope of improvement.