Porphyra farms in Korea occasionally suffer from Olpidiopsis infection. As Porphyra farming proceeds from October to March, this obligatory biotrophic parasite may need an alternative host to survive during other months of the year. To find a possible alternative summer host, we collected algae from Wando, Korea, where extensive Porphyra plantations are located, and discovered an oomycete assignable to the genus Olpidiopsis from Heterosiphonia pulchra. Host susceptibility tests showed that this oomycete could also infect Heterosiphonia japonica, Dasya sp., Dasysiphonia chejuensis, and also blades of Porphyra tenera. The minimum incubation time for this Olpidiopsis sp. to infect its hosts was approximately 4 h. Zoosporangia matured in 2 days and biflagellate zoospores were released. Free zoospores remained infective in seawater for up to 7 days. The infection of Olpidiopsis sp. to H. japonica was cell-type specific and extended rhizoid-like apical cells of determinate branches were preferentially infected. FITC-conjugated lectin staining showed specific binding of concanavalin A (ConA) to extended rhizoidlike apical cells. Attachment of Olpidiopsis sp. zoospores to the host cells was inhibited by α-mannosidase.Monosaccharide inhibition experiments showed that D(+)-mannose, complementary to the lectin ConA, could also block the infection, suggesting a lectin-carbohydrate interaction during host-parasite recognition.

A comparison of the proteome of eight genetically well-characterized isolates of the Bostrychia radicans (Mont.) Mont./B. moritziana (Sond. ex Kütz.) J. Agardh species complex was undertaken to establish if genetic relationships among them can be determined using proteome data. Genetic distances were calculated on the basis of common and distinct spots in two-dimensional gel electrophoresis (2-DE). Proteomes of the male and female plants of each population were compared to analyze the range of genetic difference within an isolate. Haploid male and female plants of the same species had 3.7%-7.1% sex-specific proteins. The degree of similarity of the proteome was consistent with previous DNA sequence data and sexual compatibility studies between the isolates. Two sexually compatible isolates from Venezuela showed a pair-wise distance ranging from 0.14 to 0.21. The isolates from Mexico and Venezuela, which were partially compatible, showed a maximum pair-wise distance of 0.26. A high level of genetic difference was found among isolates that were sexually incompatible. The isolate from Brazil was reproductively isolated from the Mexico and Venezuela isolates and showed a maximum pair-wise distance of 0.65 and 0.58, respectively. Comparative proteomics may be helpful for studying genetic distances among algal samples, if intraisolate variation (gene expression) can be minimized or tested.

Plant lectins have attracted much attention for biomedical applications including targeted drug delivery system and therapy against tumors and microbial infections. The main problem of using lectins as a biomedical tool is a batch-to-batch variation in isoforms content. The production of lectins using recombination tools has the advantage of obtaining high amounts of proteins with more precise properties, but there are only a handful of functional recombinant lectins presently available. A fetuin/asialo-fetuin specific lectin, Rhodobindin, has unique tandem repeats structure which makes it useful in exploiting for recombinant lectin. We developed three functional recombinant lectins using E. coli expression system: one from full cDNA sequence and two from fragmentary sequences of Rhodobindin. Hemagglutinating activity and solubility of the recombinant lectins were highest at OD 0.7 cell concentration at 20 °C. The optimized process developed in this study was suitable for the quality-controlled production of high amounts of soluble recombinant lectins.

In red algae, spermatial binding to female trichogynes is mediated by a lectin-carbohydrate complementary system. Aglaothamnion oosumiense is a microscopic filamentous red alga. The gamete recognition and binding occur at the surface of the hairlike trichogyne on the female carpogonium. Male spermatia are nonmotile. Previous studies suggested the presence of a lectin responsible for gamete recognition on the surface of female trychogynes. A novel N-acetyl-D-galactosamine-specific protein was isolated from female plants of A. oosumiense by affinity chromatography and named AOL1. The lectin was monomeric and did not agglutinate horse blood or human erythrocytes. The N-terminal amino acid sequence of the protein was analyzed, and degenerate primers were designed. A full-length cDNA encoding the lectin was obtained using rapid amplification of cDNA ends-PCR (RACE-PCR). The cDNA was 1,095 bp in length and coded for a protein of 259 amino acids with a deduced molecular mass of 21.4 kDa, which agreed well with the protein data. PCR analysis using genomic DNA showed that both male and female plants have this gene. However, Northern blotting and two-dimensional electrophoresis showed that this protein was expressed 12 to 15 times more in female plants. The lectin inhibited spermatial binding to the trichogynes when preincubated with spermatia, suggesting its involvement in gamete binding.T he precise point of gamete recognition varies along the continuum of reproduction and development, from directional movements that bring the compatible gametes together through many steps of fertilization to the formation of embryonic offspring. Fertilization in red algae, however, begins with direct contact between a male spermatium and a female trichogyne because both male and female gametes are nonmotile (7, 32). As spermatial binding to trichogynes is highly selective, some recognition factors are expected to be present along their surfaces (11,16,17,25). Cell surface glycoconjugates have been reported as important factors for cell-cell recognition in many organisms (24). Such recognition systems depend on complementary binding between carbohydrate moieties on one cell with specific sugar-binding lectins on another cell.Lectin-carbohydrate complementary systems have been reported in gamete recognition of marine algae for a long time (1, 8-10, 17, 22, 31), but most studies used indirect evidence from inhibition experiments using carbohydrates or foreign lectins (mostly from land plants) as blocking agents of gamete binding. Although several studies have reported on the isolation of marine algal lectins, the number of these proteins that have been purified and characterized is still small (4, 33).Our previous cytochemical study on the fertilization of Aglaothamnion oosumiense Itono suggested the presence of N-acetyl-Dgalactosamine (GalNAc) and/or D-methyl mannose-specific lectin(s) on the surface of female trichogynes (11). Here we report the purification and molecular characterization of a novel GalNAc-binding lectin from this spec...

The fingerprint recognition has been widely used for biometrics in mobile devices. Existing fingerprint sensors have already been commercialized in the field of mobile devices using primarily Si-based technologies. Recently, mutual-capacitive fingerprint sensors have been developed to lower production costs and expand the range of application using thin-film technologies. However, since the mutual-capacitive method detects the change of mutual capacitance, it has high ratio of parasitic capacitance to ridge-to-valley capacitance, resulting in low sensitivity, compared to the self-capacitive method. In order to demonstrate the self-capacitive fingerprint sensor, a switching device such as a transistor should be integrated in each pixel, which reduces a complexity of electrode configuration and sensing circuits. The oxide thin-film transistor (TFT) can be a good candidate as a switching device for the self-capacitive fingerprint sensor. In this work, we report a systematic approach for self-capacitive fingerprint sensor integrating Al-InSnZnO TFTs with field-effect mobility higher than 30 cm 2 /Vs, which enable isolation between pixels, by employing industry-friendly process methods. The fingerprint sensors are designed to reduce parasitic resistance and capacitance in terms of the entire system. The excellent uniformity and low leakage current (<10 −12 ) of the oxide TFTs allow successful capture of a fingerprint image.