Untersuchungen an Farbstoff-produzierenden Holzpilzen

Summary The fungi Peniophora sanguinea (Fr.) Bres. and Volucrispora aurantiaca Haskins were studied in regard to a possible correlation between phenoloxidases and terphenylquinone-biosynthesis.We found a production of a laccase-type-enzyme. The correlation between enzyme and pigment production is shown. Way and locus of the pigment-biosynthesis are discussed.

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Teil I: v. Massow, F., Nimz, H.: Untersuchungen an Farbstoff-produzierenden Holzpilzen. Zur Biosynthese der Peniophora sanguinea-Pigmente. Arch. Mikrobiol. 88, 147–152 (1973).     

Comparative studies of hamster calcitonin from pulmonary endocrine cells in vitro

The lung-associated peptide calcitonin (CT) has been localized by immunocytochemical means to discrete pulmonary endocrine (PE) cells. A long-term cell culture of CT-staining PE cells has been established. The molecular configuration of immunoreactive (iCT) from PE cell extracts was determined by gel chromatography, revealing predominantly large molecular weight forms of iCT. The size distribution characteristics of PE Cell iCT were similar to those of intact hamster lung. In contrast, hamster thyroid extracts contain predominantly 4000 dalton iCT (presumed monomer) and apparent iCT fragments. The culture media of the PE cells were found to contain mainly 4000 dalton iCT. We conclude that although the predominant forms of iCT found within cultured PE cells are distinct from those found within thyroidal C-cells, both iCT producing cells release mainly the monomer into the media. Malignant human bronchial carcinoid cells store predominantly monomeric iCT while secreting large molecular weight forms of iCT. Since the PE cell is the putative precursor cell to neuroendocrine malignancies, the disparity noted in the processing of CT may have significant pathobiological implications.     

Complexes of aluminium with peptide ligands: A fourier transform IR spectroscopic study

Aluminium has been recognized to be a neurotoxic agent and a risk factor in Alzheimer's disease and other neuronal dysfunctions. CD spectroscopic studies on two synthetic fragments of the human neurofilament protein midsized subunit (NF-M), and their alanine-for-serine-substituled and /or serine-phosphorylated derivatives showed the formation of stable, citric acid resistant complexes of Al³⁺with peptide ligands [M. Hollósi, Z.M. Shen, A. Perczel, and G.D. Fasman (1994) Proc. Natl. Acad. Sci. USA, vol. 9 , pp.4902-4906]. In the case of Ser-phosphorylated fragments, aβ-sheet inducing effect of Ca²⁺ and Al³⁺ ions was observed. However, the serine-containing parent peptides, NF-M 13 (KSPVPKSPVEEKG) and NF-M 17 (EEKGKSPVPKSPVEEKG), failed to show CD spectral changes reflecting β-sheet formation upon addition of Al³⁺ ions. On the basis of the amide I region of the Fourier transform ir spectra, in triftuoroethanol, the peptide backbone of NF-M17 and NF-M17 (A⁶A¹¹) shows marked changes in the presence ofAl³⁺. The most significant spectral differences are seen in the car-boxyl region (> 1700 cm^?l). The high-frequency component bands above 1760 cm^?1 in both spectra belong to the C? O of undissociated CF₃COOH. Another strong band at 1710 cm^?1 which appears only in the spectrum of NF-Ml 7 (A⁶A¹¹)(NF-M17 with Ser⁶ andSer¹¹ replaced by Ala) can be assigned to the side chain or C-terminal COOH groups. The differential proton-ation state of the carboxyl groups in the two peptides suggests the format ion ofAl³⁺ complexes of different structure and stability. The Al³⁺ complex ofNF-Ml 7 (A⁶A¹¹) is likely less stable, or one or more of the carboxylates are not coordinated to the Al³⁺ and thus can serve as a base to bind the liberated protons. In NF-M17 the OH groups of serines facilitate the formation of type [Al-pep(H_-1)] complexes with the involvement of all carboxylategroups in the molecule. The relevance of intramolecular and intermolecular Al³⁺ binding to the controversial biological role of aluminium is also discussed. © 1995 John Wiley & Sons, Inc.     

Effects of neonicotinoid seed treatments on wild bee populations in soybean and corn fields in eastern Ontario

1. Neonicotinoid-coated corn and soybean seeds are a common crop in Canada and the US. A growing body of research is demonstrating that, through various exposure routes, neonicotinoids can impact a suite of nontarget organisms including beneficial insects such as bees. However, to date, only a few studies have examined the effects of neonicotinoids in field settings.
2. We assessed the relationship between agricultural crop soil neonicotinoid levels and wild bee abundance and diversity at 16 agricultural sites representing different soil neonicotinoid levels. We detected clothianidin at 11 sites, thiamethoxam at three sites; imidacloprid was not detected.
3. Hedgerow and crop soils were consistent in terms of where clothianidin was detected; thiamethoxan was not detected in hedgerow soils. Based on model outcomes, fields with higher levels of soil neonicotinoids exhibited significantly lower wild bee abundance and diversity than those with low or no neonicotinoids detected.
4. Crop soil neonicotinoid level, hedgerow floral resource abundance and crop type were consistent predictors of bee abundance across models; only neonicotinoid level and crop type were significant predictors of diversity.
5. Our results are consistent with recent findings in the midwestern US, and underscore the potential risk of soil neonicotinoids to wild bee populations across regions and crop systems.

     

Stereoselective binding of benzodiazepines and related compounds on calmodulin-sepharose

A method has been presented to evaluate the Ca²⁺-dependent binding affinity of ligands to calmodulin (CaM) from their chromatographic retentions obtained on a CaM-Sepharose column. Enantiomers of benzodiazepines and related compounds could be separated. Among chiral calcium antagonists, verapamil showed stereoselectivity of binding. © 1995 Wiley-Liss, Inc.     

Peptide based vaccine design: synthesis and immunological characterization of branched polypeptide conjugates comprising the 276-284 immunodominant epitope of HSV-1 glycoprotein D.

The importance of the length and conjugation site of a protective epitope peptide (276SALLEDPVG284) from glycoprotein D of herpes simplex virus in branched polypeptide conjugates has been investigated. A new set of peptides, with a single attachment site and truncated sequences, was prepared. The immunogenicity of conjugates and the specificity of antibody responses elicited were investigated in BALB/c, C57/B1/6 and CBA mice. It was found that the covalent coupling of the peptide comprising the 276-284 sequence of gD through its Asp residue at position 281 did not influence the immunogenic properties of the epitope, while involvement of the side chain of Glu at position 280 almost completely abolished immunogenicity. These results clearly indicated that the conjugation site of the epitope peptide influenced the intensity and specificity of antibody responses. Comparison of the immunological properties of conjugates containing truncated gD peptides revealed the presence of two epitopes within the 276-284 region. One of the proposed epitopes is situated at the N-terminal (276-281) region, while the other is located at the C-terminal end of the sequence (279-284). Binding data demonstrated that some of the peptides comprising these epitopes induced gD-specific responses in their conjugated form and also elicited an immune response that conferred protection against lethal HSV-1 infection. The correlation of peptide- and gD-specific antibody responses with the protective effect of the immune response is discussed.