A Symbiont-Produced Protein and Bacterial Symbiosis in Amoeba proteus

ABSTRACT. Gram- symbiotic X-bacteria present in the xD strain of Amoeba proteus as required cell components, synthesize and export a large amount of a 29-kDa protein (S29x) into the host's cytoplasm across bacterial and symbiosome membranes. The S29x protein produced by E. coli transformed with the s29x gene is also rapidly secreted into the culture medium. Inside amoebae, S29x enters the host's nucleus as detected by confocal and irnmunoelectron microscopy, although it is not clear if S29x is selectively accumulated inside the nucleus. The deduced amino-acid sequence of S29x has a stretch of basic amino acids that could act as a nuclear localization signal, but there is no signal peptide at the N-terminus and the transport of S29x is energy independent. The functions of S29x are not known, but in view of its prominent presence inside the amoeba's nucleus, S29x is suspected to be involved in affecting the expression of amoeba's nuclear gene(s).     

Double intratibial injection of human tonsil-derived mesenchymal stromal cells recovers postmenopausal osteoporotic bone mass

Background and aims

Osteoporosis, which is a disease characterized by weakening of the bone, affects a large portion of the senior population. The current therapeutic options for osteoporosis have side effects, and there is no effective treatment for severe osteoporosis. Thus, we urgently need new treatment strategies, such as topical therapies and/or safe and effective stem cell therapies.

Feeding by Phototrophic Red-Tide Dinoflagellates on the Ubiquitous Marine Diatom Skeletonema costatum

ABSTRACT We investigated feeding by phototrophic red‐tide dinoflagellates on the ubiquitous diatom Skeletonema costatum to explore whether dinoflagellates are able to feed on S. costatum, inside the protoplasm of target dinoflagellate cells observed under compound microscope, confocal microscope, epifluorescence microscope, and transmission electron microscope (TEM) after adding living and fluorescently labeled S. costatum (FLSc). To explore effects of dinoflagellate predator size on ingestion rates of S. costatum, we measured ingestion rates of seven dinoflagellates at a single prey concentration. In addition, we measured ingestion rates of the common phototrophic dinoflagellates Prorocentrum micans and Gonyaulax polygramma on S. costatum as a function of prey concentration. We calculated grazing coefficients by combining field data on abundances of P. micans and G. polygramma on co‐occurring S. costatum with laboratory data on ingestion rates obtained in the present study. All phototrophic dinoflagellate predators tested (i.e. Akashiwo sanguinea, Amphidinium carterae, Alexandrium catenella, Alexandrium tamarense, Cochlodinium polykrikoides, G. polygramma, Gymnodinium catenatum, Gymnodinium impudicum, Heterocapsa rotundata, Heterocapsa triquetra, Lingulodinium polyedrum, Prorocentrum donghaiense, P. micans, Prorocentrum minimum, Prorocentrum triestinum, and Scrippsiella trochoidea) were able to ingest S. costatum. When mean prey concentrations were 170–260 ng C/ml (i.e. 6,500–10,000 cells/ml), the ingestion rates of G. polygramma, H. rotundata, H. triquetra, L. polyedrum, P. donghaiense, P. micans, and P. triestinum on S. costatum (0.007–0.081 ng C/dinoflagellate/d [0.2–3.0 cells/dinoflagellate/d]) were positively correlated with predator size. With increasing mean prey concentration of ca 1–3,440 ng C/ml (40–132,200 cells/ml), the ingestion rates of P. micans and G. polygramma on S. costatum continuously increased. At the given prey concentrations, the maximum ingestion rates of P. micans and G. polygramma on S. costatum (0.344–0.345 ng C/grazer/d; 13 cells/grazer/d) were almost the same. The maximum clearance rates of P. micans and G. polygramma on S. costatum were 0.165 and 0.020 μl/grazer/h, respectively. The calculated grazing coefficients of P. micans and G. polygramma on co‐occurring S. costatum were up to 0.100 and 0.222 h, respectively (i.e. up to 10% and 20% of S. costatum populations were removed by P. micans and G. polygramma populations in 1 h, respectively). Our results suggest that P. micans and G. polygramma sometimes have a considerable grazing impact on populations of S. costatum.     

New microsatellite markers for the snow crab Chionoecetes opilio (Brachyura: Majidae)

Nine novel microsatellite loci were isolated from Chionoecetes opilio by screening an enriched genomic library using nonradioactive polymerase chain reaction techniques, and the polymorphisms were examined to estimate genetic variability. The genetic variabilities varied depending on the locus. All loci were found to be polymorphic with an average of 9.7 alleles per locus (range 3–25). The observed and expected heterozygosities ranged from 0.80 to 0.98 and from 0.56 to 0.95, respectively. Five loci showed significant Hardy–Weinberg disequilibrium at the P < 0.05 level. The high variabilities revealed in this study suggest that these microsatellite loci should provide useful markers for genetic variation monitoring of C. opilio.     

Characterization of new microsatellite markers in mung bean,Vigna radiata (L.)

The present work reports the isolation and characterization of new polymorphic microsatellites in mung bean (Vigna radiata L.). Of 93 designed primer pairs, seven were found to amplify polymorphic microsatellite loci, which were then characterized using 34 mung bean accessions. The number of alleles ranged from two to five alleles per locus with an average of three alleles. Observed and expected heterozygosity values ranged from 0 to 0.088 and from 0.275 to 0.683, respectively. All seven loci showed significant deviations from Hardy–Weinberg equilibrium, whereas only one pairwise combination (GBssr‐MB77 and GBssr‐MB91) exhibited significant departure from linkage disequilibrium. These newly developed markers are currently being utilized for diversity assessment within the mung bean germplasm collection of the Korean Gene Bank.     

Cloning and expression profiles of tumor suppressor QM homologue in response to granulovirus in Pieris rapae

The tumor suppressor, QM, has been cloned and characterized from various model organisms such as human, plant and invertebrates. Yet, it has not been seriously investigated for its role in conjunction with antiviral mechanisms involving innate insect immunity. From the expressed sequence tag (ESTs) project, conducted with larval cDNA library of cabbage butterfly, Pieris rapae, a partial fragment (718 bp) of QM homologue, termed PrQM containing 660 bp long open reading frame (ORF) encoding protein of 219 amino acids was identified. In silico analysis of PrQM ORF revealed the presence of ribosomal protein L10a/L10e type domain. Phylogenetic analysis of the P. rapae QM‐like protein showed high amino acid sequence similarity with other PrQM polypeptides identified from Heliothis virescenes (95%), Plutella rapae (92%), Bombyx mori (92%), Drosophila melanogaster (89%), and Polyrhachis vicina (85%). The butterfly QM has the closest phylogenetic relationship to a moth (Hv) QM homologue. Further investigations revealed the expression of PrQM at all developmental stages, with pronounced presence at the egg stage. In addition, spatial pattern analysis indicated its high expression in the head, salivary gland, integument and fat body with visible presence in Malpighian tubule and gut. Time course expression studies conducted after immune‐challenge with lipoteichoic acid (LTA) showed the induction of PrQM mRNA at 12 h and 24 h after challenge and also in response to granulovirus (GV). Results of this investigation therefore suggest possible role of QM‐like proteins from Pieris rapae to be involved in innate antiviral immune responses. Further elucidation on the precise function of PrQM during antiviral immune responses by using RNA interference remains a viable research front.