Molecular and biological characterization of a mannan-binding lectin from the holothurian Apostichopus japonicus

To elucidate the origin and evolution of mannan-binding lectins (MBL), a new C-type lectin (CTL) specific for high-mannose glycans (MBL-AJ) was isolated from the coelomic plasma of the holothurian Apostichopus japonicus. MBL-AJ has oligomeric forms with identical 17-kDa subunits on SDS-PAGE. Among natural ligands, lectin hemagglutination activity was competitively inhibited by extracellular low-branched, but not high-branched, alpha-D-mannans isolated from marine halophilic bacteria and composed of alpha-1,2 and alpha-1,6 linked D-mannose residues. This suggests that the lectin interacts with backbone or inner side chain mannose residues, but not with terminal ones. The activity of the lectin was Ca(2+)-, pH-, and temperature-dependent. MBL-AJ cDNA was cloned from a holothurian coelomocyte cDNA library. The subunit of the mature protein has 159 amino acids and a single carbohydrate-recognition domain (CRD) of CTL. CRD contains a Glu-Pro-Asp amino acid sequence (EPN-motif) conserved for all known MBLs. A monospecific polyclonal antibody against MBL-AJ was obtained using the 34-kDa lectin dimer as an immunogen. The MBL-AJ has demonstrated immunochemical identity to the earlier isolated mannan-binding CTL from another holothurian, Cucumaria japonica. But a more interesting finding was cross-reactivity of MBL-AJ and human serum MBL detected by the antibody against MBL-AJ. Taking into consideration such MBL-AJ peculiarities as its carbohydrate specificity, the presence of a conserved region forming the mannose-binding site, common antigenic determinants with human MBL, and participation in defense reactions, it is possible that MBL-AJ belongs to the family of evolutionary conserved mannan-binding proteins.     

Types of Higher Nervous Activity in Pigs: Characteristics of Behavior and Effects of Technological Stress

Neurophysiology - The strength, balance, and mobility of central nervous processes, which determine behavior, were estimated in six-month-old pigs of the Large White breed. According to the...     

Characteristic Immunohematological Parameters of Migratory (Vespertilio murinus Linnaeus, 1758) and Resident (Myotis dasycneme Boie, 1825) Bat Species of the Ural Fauna

Doklady Biological Sciences - The results of the first comparative analysis of hematological parameters of bats from natural populations of the Ural region are presented: the pond bat (Myotis...     

Ammonium nitrate improves direct somatic embryogenesis and biolistic transformation of Triticum aestivum

Triticum aestivum is of major importance both nutritionally and economically. Introduction of new genes has been difficult to apply to elite wheat varieties mainly as a result of their recalcitrance to prerequisite tissue culture. We attempted to improve the frequency of wheat transformation by exposing plants to high level of ammonium nitrate. Our experiments showed that modification of the ammonium nitrate content in the direct somatic embryogenesis induction medium can increase the number of primary embryos produced over twofold in the elite hard red wheat cultivar Superb. The number of primary embryos that were capable of transitioning into shoot development also increased twofold. Biolistic transformation efficiency improved as much as sevenfold when targeted scutellar tissue was exposed to elevated ammonium nitrate levels. This simple approach could become extremely useful for increasing transformation efficiency in wheat.     

Structural Basis for Phototoxicity of the Genetically Encoded Photosensitizer KillerRed

KillerRed is the only known fluorescent protein that demonstrates notable phototoxicity, exceeding that of the other green and red fluorescent proteins by at least 1,000-fold. KillerRed could serve as an instrument to inactivate target proteins or to kill cell populations in photodynamic therapy. However, the nature of KillerRed phototoxicity has remained unclear, impeding the development of more phototoxic variants. Here we present the results of a high resolution crystallographic study of KillerRed in the active fluorescent and in the photobleached non-fluorescent states. A unique and striking feature of the structure is a water-filled channel reaching the chromophore area from the end cap of the β-barrel that is probably one of the key structural features responsible for phototoxicity. A study of the structure-function relationship of KillerRed, supported by structure-based, site-directed mutagenesis, has also revealed the key residues most likely responsible for the phototoxic effect. In particular, Glu⁶⁸ and Ser¹¹⁹, located adjacent to the chromophore, have been assigned as the primary trigger of the reaction chain.     

Circulating anti-p53 antibodies in esophageal cancer patients

Circulating anti-p53 protein antibodies (p53-Abs) have been detected in some cancer patients. The aim of the study was to determine the presence of circulating anti-p53 protein antibodies and their clinical significance in patients with esophageal carcinoma. Serum specimens from 75 consecutive patients with squamous cell carcinomas and 10 healthy subjects were studied. Enzyme linked immunosorbent assay (ELISA--Pharma Cell) was used to detect p53-Abs. At the time of diagnosis 20 (26.6%) of 75 analyzed patients had positive result in the p53-Abs test, but not any of the healthy subjects. The positive rate was 25% (1/4) cases in stage I, 41% (10/24) cases in stage IIA, 0% (0/8) cases in stage IIB, 28% (8/28) cases in stage III and 9% (1/11) cases in stage IV. In respect of tumour differentiation, cases graded as G1, G2 and G3 were positive in 28.5% (4/14), 25.9% (7/27) and 26.4% (9/34), respectively. There was no correlation between presence of p53-Abs and stage, rumour differentiation, lymph nodes metastases, tumour size, patient age and sex. In conclusion, the results of the present study indicate that serum p53-Abs did not correlate with cliniocopathologic feature of esophageal carcinoma.     

Correction to: Wheat wounding-responsive HD-Zip IV transcription factor GL7 is predominantly expressed in grain and activates genes encoding defensins

Plant Molecular Biology - Due to an unfortunate turn of events, the panels O to S are missing in Fig. 8 of the original publication. The correct Fig. 8 and its caption is...     

Complex-dependent histone acetyltransferase activity of KAT8 determines its role in transcription and cellular homeostasis

1. Download : Download high-res image (142KB)
2. Download : Download full-size image