Evaluation of UVB reduction by materials commonly used in reptile husbandry

Ultraviolet B (UVB) irradiation (285–320 nm) is considered important for metabolic processes and reproduction in many reptile species by facilitating the synthesis of vitamin D₃. In captivity, UVB radiation reaching an animal may be diminished by the properties of the materials used in enclosure construction. We investigated the UVB‐attenuating properties of 14 materials commonly used in cage tops for reptile enclosures. Irradiances were measured by two types of hand‐held broadband radiometers and the D₃‐synthesizing potential was assessed by the use of an in vitro model. For UV‐transmitting acrylic, a significant discrepancy between meter irradiances and in vitro model values for D₃‐synthesizing ability was observed, with meter readings underestimating the blocking effect. In contrast, attenuation of UVB irradiances by air‐permeable materials, such as wire screen, measured with meters was generally comparable to the attenuation of D₃‐synthesizing ability as measured by in vitro models. Relatively simple meter readings can therefore be used to reflect reduction of D₃‐synthesizing ability through air‐permeable materials. Zoo Biol 26:417–423, 2007. © 2007 Wiley‐Liss, Inc.     

Involvement of carbohydrates as multiple low affinity interaction sites in the self-association of the aggregation factor from the marine sponge Microciona prolifera

Cell aggregation in the marine sponge Microciona prolifera is mediated by a multimillion molecular weight aggregation factor (MAF) and is based on two functional properties, a Ca2+-independent cell binding activity and a Ca2+-dependent factor-factor self-interaction. Monoclonal antibodies were prepared against purified MAF, and one clone was characterized which selectively inhibited the MAF-MAF association activity. Binding of the blocking antibody (Block 1) to MAF demonstrated that this epitope structure was present in 1100 copies per one MAF molecule of Mr = 2 X 10(7). Such blocking antibodies precipitated a small molecular weight protein-free glycan fraction prepared from MAF by Pronase digestion, thus indicating that the highly repetitive epitope is located in the carbohydrate portion of the molecule. Since the inhibitory activity of the Block 1 antibody could only be achieved when most of the sites were occupied by Fab fragments of this antibody, the self-association of MAF seemed to be based on the polyvalency of the carbohydrate determinants. The affinity of the protein-free glycans was very low as shown by the fact that they did not display any measurable self or MAT binding activity in their monomeric form. After cross-linking them with glutaraldehyde into polymers of the size of MAF, however, the self-interaction could be reconstituted. Thus, the MAF-MAF association activity, which is needed for cell aggregation in sponges, seems to be based on multiple low affinity carbohydrate-carbohydrate interactions, which is different from most interactions mediated by adhesion molecules characterized so far.     

Nicotinamide: suppression of lymphocyte transformation with a component identified in human transfer factor.

The component in human transfer factor (TF) (Fraction IV, from exclusion chromatography on Sephadex G-25) responsible for suppression of antigen-induced lymphocyte transformation was previously identified as nicotinamide. Commercially available nicotinamide was subsequently shown to produce suppression of antigen-induced responses in vitro previously observed with TF Fraction IV. Nicotinamide was found to be nontoxic at the highest concentrations employed (10(-2)M) and suppressive over a relatively broad range (10(-5) to 10(-2)M. The suppression appeared to be related to the magnitude of antigen- or mitogen-induced transformation and was apparent even when nicotinamide was added as late as 48 hr after stimulant addition.     

UHPLC‐HRMS/MS Based Profiling of Algerian Lichens and Their Antimicrobial Activities

Lichens are complex symbiotic organisms able to produce a vast array of compounds. The Algerian lichen diversity has only prompted little interest even given the 1085 species listed. Herein, the chemodiversity of four Algerian lichens including Cladonia rangiformis, Ramalina farinaceae, R. fastigiata, and Roccella phycopsis was investigated. A dereplication strategy, using ultra high performance liquid chromatography‐high resolution‐electrospray ionization‐mass spectrometry (UHPLC‐HRMS/MS), was carried out for a comprehensive characterization of their substances including phenolics, depsides, depsidones, depsones, dibenzofurans, and aliphatic acids. Some known compounds were identified for the first time in some species. Additionally, the lichenic extracts were evaluated for their antifungal and antimicrobial activities on human pathogenic strains (Candida albicans, C. glabrata, Aspergillus fumigatus, Staphylococcus aureus, and Escherichia coli). Cyclohexane extracts were found particularly active against human pathogenic fungi with MIC₈₀ values ranging from 8 to 62.5 μg/mL, without cytotoxicity. This study highlights the therapeutic and prophylactic potential of lichenic extracts as antibacterial and antifungal agents.     

Loss of Paneth Cell Autophagy Causes Acute Susceptibility to Toxoplasma gondii-Mediated Inflammation

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A highly efficient transposon mutagenesis system for the tomato pathogen Clavibacter michiganensis subsp. michiganensis.

A transposon mutagenesis system for Clavibacter michiganensis subsp. michiganensis was developed based on antibiotic resistance transposons that were derived from the insertion element IS1409 from Arthrobacter sp. strain TM1 NCIB12013. As a prerequisite, the electroporation efficiency was optimized by using unmethylated DNA and treatment of the cells with glycine such that about 5 x 10(6) transformants per microg of DNA were generally obtained. Electroporation of C. michiganensis subsp. michiganensis with a suicide vector carrying transposon Tn1409C resulted in approximately 1 x 10(3) transposon mutants per pg of DNA and thus is suitable for saturation mutagenesis. Analysis of Tn1409C insertion sites suggests a random mode of transposition. Transposition of Tn1409C was also demonstrated for other subspecies of C. michiganensis.