Estimation of the degree of self-fertilization in Porphyra yezoensis (Bangiales,Rhodophyta)

Crosses between genotypically distinct thalli of the monoecious species Porphyra yezoensis were carried out using immature thallus fragments from green- and red-type color mutants and also wild-type thalli. As the genes governing the mutants are monogenic, recessive to the wild-type, and belong to the same linkage group, the degree of self-fertilization could be estimated based on the pigmentation of the resultant diploid conchocelis. The degree of self-fertilization in the cross between the green-type and the wild-type was 48.5–55.0%, and in the cross between the red-type and the wild-type was 45.1–56.5%. In the cross between the green- and red-type mutants, the degree of self-fertilization was 46.0–54.5% when the green-type was the female parent, and was 44.8–55.6% when the red-type was the female parent.     

Rumen ciliated protozoan fauna of the yak (Bos grunniens) in China with the description of Entodinium monuo n. sp

Rumen ciliate species composition was surveyed in domestic yaks kept in Tibet, Sichuan, and Inner Mongolia, China. Twelve genera including 36 species with 18 formae were identified. The species compositions were slightly different among the three areas: yaks in Tibet had the simplest fauna, in contrast, the fauna of yaks in Inner Mongolia were the most abundant and similar to those found in the cattle kept in the same area. This suggests that the rumen ciliate composition of yaks is affected by that of cattle kept together or in proximity. A new species belonging to the genus Entodinium, Entodinium monuo n. sp., was recognized from the yaks in all areas. This new species was common in the yaks but was not detected in the cattle fed near yaks in Inner Mongolia. There was a similar generic ciliate composition in yaks kept in respective areas. Entodinium was the most predominate ciliate (51.9-61.0%) with total ciliate densities estimated as 10(5)/ml per yak.     

Effect of DNA length and H4 acetylation on the thermal stability of reconstituted nucleosome particles

To examine the factors involved with nucleosome stability, we reconstituted nonacetylated particles containing various lengths (192, 162, and 152 base pairs) of DNA onto the Lytechinus variegatus nucleosome positioning sequence in the absence of linker histone. We characterized the particles and examined their thermal stability. DNA of less than chromatosome length (168 base pairs) produces particles with altered denaturation profiles, possibly caused by histone rearrangement in those core-like particles. We also examined the effects of tetra-acetylation of histone H4 on the thermal stability of reconstituted nucleosome particles. Tetra-acetylation of H4 reduces the nucleosome thermal stability by 0.8 degrees C as compared with nonacetylated particles. This difference is close to values published comparing bulk nonacetylated nucleosomes and core particles to ones enriched for core histone acetylation, suggesting that H4 acetylation has a dominant effect on nucleosome particle energetics.     

Effect of anion binding on the thermal reverse reaction of bathoiodopsin: anion stabilizes two forms of iodopsin

The thermal reactions of the bathoproduct of the long wavelength sensitive visual pigment iodopsin were investigated under various anionic and environmental conditions, to get an insight into the mechanism leading to the unusual thermal isomerization of the retinal chromophore from the trans to the 11-cis form at very low temperatures (-160 degrees C). The all-trans chromophore of the bathoiodopsin produced from iodopsin in the presence of chloride thermally reverted to the 11-cis form, while in the presence of nitrate it kept its all-trans configuration upon warming. Different protein environments, either in a detergent or in phosphatidylcholine (PC) liposomes, did not change the reaction characteristics of the bathoiodopsins under the two anionic conditions. However, reaction characteristics of bathoiodopsins produced in the absence of small anions were dependent on the environment. The trans-to-cis isomerization occurred upon warming of bathoiodopsin in the presence of detergent but not in liposomes. Spectral measurements revealed that iodopsin in the absence of small anions is a mixture of two spectrally distinct forms that exhibit absorption maxima and reaction characteristics similar to those of chloride-bound and nitrate-bound iodopsins, respectively. Thus, iodopsin exhibits two conformational states, each of which is stabilized by the binding of chloride and nitrate, respectively.     

Immunologic characterization and molecular profile of carcinoembryonic antigen detected by monoclonal antibodies

Four distinct monoclonal antibodies, which reacted with CEA preparations but not with nonspecific cross-reacting antigen or with nonspecific cross-reacting antigen 2, were established. Except for monoclonal antibody AS001 , all of these monoclonal antibodies immunoprecipitated molecular forms of 200K and 180K daltons that are not bridged by disulfide bonds. Immunodepletion experiments and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis revealed that these monoclonal antibodies recognized the same antigenic structure when 125I-CEA preparation was used. Monoclonal antibody AS001 is of particular interest, because this antibody reacted only with a 200K dalton molecule which is a part of the molecules recognized by the other three monoclonal antibodies. The rosette inhibition assay and the immunoprecipitation experiments suggest that each monoclonal antibody recognizes a different antigenic determinant. The antigenic determinants recognized by monoclonal antibodies YK013 and AS001 may be peptides in nature, whereas the determinants recognized by antibodies YK024 or AS005 might be carbohydrate. The radioimmunoassay with monoclonal antibody AS001 was established, and the results clearly indicate that the incidence of positivity for the sera from digestive tract cancer patients and from lung cancer patients obtained by monoclonal antibody AS001 was higher than that obtained by the polyclonal antibody. Monoclonal antibody AS001 was able to detect the corresponding antigen in the sera, which the polyclonal antibody failed to detect. This study therefore suggests that monoclonal antibodies may enhance and improve the diagnostic value in cancer patients with undetectable or lower CEA levels detected by conventional anti-CEA antibodies.     

Typical three-domain cry proteins of Bacillus thuringiensis strain A1462 exhibit cytocidal activity on limited human cancer cells

Bacillus thuringiensis strain A1462 produced two parasporal inclusion proteins with a molecular mass of 88 kDa that were converted to 64-kDa toxins when activated by proteinase K digestion. Both toxins exhibited strong cytocidal activity against two human cancer cell lines, HL60 (myeloid leukemia cells) and HepG2 (liver cancer cells), while low or no toxicities were observed against 11 human and three mammalian cell lines, including four non-cancer cell lines. The cytotoxicity of both toxins on susceptible cells was characterized by rapid cell swelling. Gene cloning experiments provided two novel genes encoding 88-kDa Cry proteins, Cry41Aa and Cry41Ab. The amino acid sequences of the two proteins contain five block regions commonly conserved in B. thuringiensis insecticidal Cry proteins. This is the first report of the occurrence of typical three-domain Cry proteins with cytocidal activity preferential for cancer cells.     

Timing of administration of transforming growth factor-beta and epidermal growth factor influences the effect on material properties of the in situ frozen-thawed anterior cruciate ligament

One of the future goals in ligament reconstruction is to prevent graft deterioration after transplantation. The aim of this study is to clarify whether an administration of TGF-beta1 and EGF significantly affect biomechanical properties of the in situ frozen-thawed anterior cruciate ligament (ACL), an ACL autograft model, and to elucidate whether the timing of this administration may influence its effect. Rabbits were randomly divided into 4 groups after the freeze-thaw treatment with liquid nitrogen was applied to the right knee. In 2 groups, 4-ng TGF-beta1 and 100-ng EGF mixed with 0.2-ml fibrin sealant were applied around the ACL at 3 and 6 weeks after the treatment, respectively. In the remaining two groups, only 0.2-ml fibrin sealant was applied around the ACL at 3 and 6 weeks, respectively. In each group, all animals were sacrificed at 12 weeks after the freeze-thaw treatment. These growth factors applied at 3 weeks significantly inhibited not only the increase of water content and the cross-sectional area of the ACL but also reduction of the tensile strength and the tangent modulus of the ACL (p<0.0001), which were induced by the freeze-thaw treatment. However, the application at 6 weeks did not significantly affect the changes of these parameters after the treatment. This study demonstrated that the timing of administration of TGF-beta and EGF after the freeze-thaw treatment significantly influences its effect on the biomechanical properties of the frozen-thawed ACL.