Viability Testing of Orchid Seed and the Promotion of Colouration and Germination

This study reports the ability of Fusarium to induce orchidseed colouration and germination. The in vitro bioassay germinationtest, using a Fusarium isolate from the protocorm of Cypripediumreginae, was compared with standard chemical procedures of triphenyltetrazolium chloride (TTC) and acid fuchsin (AC) for testingseed viability. With Cypripedium reginae, Cypripedium parviflorumand Platanthera grandiflora, the efficiency of the bioassaywas similar to that of the TTC and AC procedures. However, thebioassay was more appropriate for estimating embryo viabilityafter a prolonged seed pretreatment (more than 2 h) in 10% sodiumhypochlorite, a surface sterilant often used to enhance germinationof terrestrial species. We also obtained in vitro Cypripediumreginae seed germination induction and protocorm formation bythe same Fusarium isolate. This is the first confirmation ofBernard's early reports that orchid fusaria could stimulateseed germination (Bernard N. 1990.Révue Généralede Botanique12 : 108–120). However, the importance ofthe non-mycorrhizal Fusarium fungus in promoting germinationseems to be relatively minor compared to that of specificRhizoctoniaorchid mycorrhizas. Our results are discussed in light of thecurrent North American strategy on orchid conservation methodswhich proposes the use of symbiotic germination.Copyright 2000Annals of Botany Company Orchid, Cypripedium, Platanthera, seed, Fusarium, bioassay, staining, viability, germination, protocorm, mycorrhiza     

Affinity recovery of eight HER2-binding affibody variants using an anti-idiotypic affibody molecule as capture ligand

Affibody molecules generated by combinatorial protein engineering to bind the human epidermal growth factor receptor 2 (HER2) have in earlier studies proven to be promising tracers for HER2-mediated molecular imaging of cancer. Amino acid extensions either at the N- or C-terminus of these Z(HER2) affibody molecules, have been successfully employed for site-specific radiolabeling of the tracer candidates. Hexahistidyls or other tags, which would be convenient for recovery purposes, should be avoided since they could negatively influence the tumor targeting efficacy and biodistribution properties of the tracer. Using a new ?-lactamase-based protein fragment complementation assay (PCA), an affibody molecule was isolated which bound a Z(HER2) affibody molecule with sub-micromolar affinity, but not unrelated affibody molecules. This suggests that the interacting area include the HER2-binding surface of Z(HER2). This novel anti-idiotypic affibody molecule Z(E01) was produced in Escherichia coli, purified, and chemically coupled to a chromatography resin in order to generate an affibody-based affinity column, suitable for recovery of different variants of Z(HER2) affibody molecules, having a common binding surface for HER2. Eight such Z(HER2) affibody molecules, designed for future radioimaging investigations, having different C-terminal peptide extensions aimed for radioisotope ((??m)Tc)-chelation, were successfully produced and recovered in a single step to high purity using the anti-idiotypic affibody ligand for the affinity purification. These results clearly suggest a potential for the development of anti-idiotypic affibody-based resins for efficient recovery of related variants of a target protein that might have altered biochemical properties, thus avoiding the cumbersome design of specific recovery schemes for each variant of a target protein.     

Identification of Nedd4 E3 ubiquitin ligase as a binding partner and regulator of MAK-V protein kinase

MAK-V/Hunk is a scantily characterized AMPK-like protein kinase. Recent findings identified MAK-V as a pro-survival and anti-apoptotic protein and revealed its role in embryonic development as well as in tumorigenesis and metastasis. However molecular mechanisms of MAK-V action and regulation of its activity remain largely unknown. We identified Nedd4 as an interaction partner for MAK-V protein kinase. However, this HECT-type E3 ubiquitin ligase is not involved in the control of MAK-V degradation by the ubiquitin-proteasome system that regulates MAK-V abundance in cells. However, Nedd4 in an ubiquitin ligase-independent manner rescued developmental defects in Xenopus embryos induced by MAK-V overexpression, suggesting physiological relevance of interaction between MAK-V and Nedd4. This identifies Nedd4 as the first known regulator of MAK-V function.     

Hen egg white lysozyme fibrillation: a deep‐UV resonance Raman spectroscopic study

Amyloid fibrils are associated with numerous degenerative diseases. The molecular mechanism of the structural transformation of native protein to the highly ordered cross‐β structure, the key feature of amyloid fibrils, is under active investigation. Conventional biophysical methods have limited application in addressing the problem because of the heterogeneous nature of the system. In this study, we demonstrated that deep‐UV resonance Raman (DUVRR) spectroscopy in combination with circular dichroism (CD) and intrinsic tryptophan fluorescence allowed for quantitative characterization of protein structural evolution at all stages of hen egg white lysozyme fibrillation in vitro. DUVRR spectroscopy was found to be complimentary to the far‐UV CD because it is (i) more sensitive to β ‐sheet than to α ‐helix, and (ii) capable of characterizing quantitatively inhomogeneous and highly light‐scattering samples. In addition, phenylalanine, a natural DUVRR spectroscopic biomarker of protein structural rearrangements, exhibited substantial changes in the Raman cross section of the 1000‐cm^–1 band at various stages of fibrillation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Molecular Co-occupancy Identifies Transcription Factor Binding Cooperativity In Vivo

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Standardized Aronia melanocarpa extract regulates redox status in patients receiving hemodialysis with anemia

Molecular and Cellular Biochemistry - The aim of our study was to investigate the effects of one-month consumption of polyphenol-rich standardized Aronia melanocarpa extract (SAE) on redox status...     

Two Metabolic Fuels,Glucose and Lactate,Differentially Modulate Exocytotic Glutamate Release from Cultured Astrocytes

Neurochemical Research - Astrocytes have a prominent role in metabolic homeostasis of the brain and can signal to adjacent neurons by releasing glutamate via a process of regulated exocytosis....     

Mitochondrial Disorders in Alzheimer’s Disease

Biochemistry (Moscow) - Alzheimer’s disease is the most common age-related neurodegenerative disease. Understanding of its etiology and pathogenesis is constantly expanding. Thus, the...     

A Crosstalk between the Biorhythms and Gatekeepers of Longevity: Dual Role of Glycogen Synthase Kinase-3

Biochemistry (Moscow) - This review discusses genetic and molecular pathways that link circadian timing with metabolism, resulting in the emergence of positive and negative regulatory feedback...