Modelling intraspecific resting egg shape variation in a freshwater fairy shrimp Tanymastix stagnalis (L., 1758) (Crustacea, Branchiopoda)

The shape of the resting eggs of a large branchiopod crustacean, the Anostraca Tanymastix stagnalis , is represented very accurately by analytical expressions. The occurrence of atypical shape of some T. stagnalis eggs may be viewed as a simple change of the analytical expression describing the usual egg shape. Their unusual shape may be explained by a higher embryo volume within an envelope of a given size. Biological implications are briefly discussed and hypothesized in an evolutionary point of view.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 55–60.     

Antibody-induced association between discrete regions of HLA class I and II antigens

The anti-HLA-DR + DP monoclonal antibody (MoAb) CR11-462 was unexpectedly found to cross-inhibit the binding to B lymphoid cells of the anti-HLA Class I MoAb CR10-215 and CR11-115. The latter two antibodies recognized the same or spatially close antigenic determinant. The cross-blocking of anti-HLA Class I MoAb CR10-215 and CR11-115 by MoAb CR11-462 reflects neither its contamination by anti-HLA Class I antibodies nor its cross-reactivity with HLA Class I antigens. On the other hand, the cross-blocking appears to reflect redistribution of HLA Class II antigens by the MoAb CR11-462, since the MoAb CR10-215 and CR11-115 are not susceptible to blocking when lymphoid cells are treated with 0.025% glutaraldehyde or are coated with Fab' fragments of the MoAb CR11-462. Furthermore, immunoprecipitates from B lymphoid cells preincubated with the MoAb CR11-462 before solubilization contain HLA Class I antigens. Therefore, these results have shown for the first time an antibody-induced association between discrete regions of HLA Class I and Class II antigens on the membrane of B lymphoid cells.     

The establishment of IL-2 producing cells by genetic engineering

Expression plasmids containing human interleukin-2(IL-2) cDNA under the control of viral promoters (SV40 early region, MuLV LTR, HTLV-I LTR, and ASV (Y73) LTR) were introduced into TK- mouse L cells and human FL cells to establish IL-2 producing cells. The highest levels of IL-2 producing clones were obtained in TK+ mouse L cells transformed with a recombinant plasmid having MuLV LTR as a promoter, whereas transformed cells of human FL cells (G418r) were revealed to produce IL-2 at the highest level when the cells were transfected with a plasmid containing HTLV LTR as a promoter. These results suggest that these promoter/enhancer regions possess different cell specificities in gene expression. To obtain higher levels of IL-2 production using gene amplification, the hybrid plasmids containing the hamster DHFR and human IL-2 genes were constructed and transfected into DHFR- CHO cells. DHFR+ colonies produced IL-2 at about the same level as that produced by TK+ L cells transformed with the recombinants containing MuLV LTR. Selection of methotrexate-resistant cells resulted in a 5- to 30-fold increase of IL-2 production. These cells produced IL-2 stably for at least 3 months, even in the absence of methotrexate.     

Decrease of palmitoyl-CoA elongation in platelets and leukocytes in the patient of hereditary methemoglobinemia associated with mental retardation

Effect of the deficiency of NADH-cytochrome b5 reductase on fatty acid elongation was studied in the platelets and leukocytes taken from a patient of hereditary methemoglobinemia associated with mental retardation. The activity of fatty acid elongation was determined by measuring the incorporation of [2-14C]malonyl-CoA into palmitoyl-CoA. The de novo biosynthesis of fatty acids was blocked by the addition of phosphotransacetylase, and the elongation system could be assayed in the homogenates separated from de novo biosynthesis. As compared to normal subjects approximately 40% decrease of fatty acid elongation was observed both in the platelets and leukocytes from the patient.     

Structure and function relationship of staphylocoagulase

The bacterial protein staphylocoagulase binds stoichiometrically to human prothrombin, resulting in a coagulant complex, staphylothrombin. The enzymatic properties of staphylothrombin differ from those of -thrombin in their substrate specificities toward natural and synthetic substrates, in addition to their interaction with protease inhibitors. In order to obtain information about the region of staphylocoagulase that interacts with human prothrombin, staphylocoagulase was cleaved by -chymotrypsin. Limited -chymotryptic cleavage of staphylocoagulase yielded three large fragments, of 43, 30, and 20 kD. The 43-kD fragment exhibited a high affinity for human prothrombin (K_d=1.7 nM), which is comparable to the affinity observed using intact staphylocoagulase (K_d=0.46 nM). A complex of the 43-kD fragment and prothrombin possessed both clotting and amidase activity essentially identical to that observed in a complex of intact staphylocoagulase and prothrombin. The 30-kD fragment exhibited weaker affinity for prothrombin (K_d=120 nM.) While clotting activity was not observed with a complex of this fragment and prothrombin, it nonetheless possessed a weak amidase activity. The 20-kD fragment was found only to bind to prothrombin. The NH₂-terminal sequence analyses of these fragments revealed that the 43-kD fragment constitutes the NH₂-terminal portion of staphylocoagulase, and contains the 30-kD and 20-kD fragments. It is therefore concluded that the functional region of staphylocoagulase for binding and activation of prothrombin is localized in the NH₂-terminal region of the intact protein. The 43-kD fragment contained 324 amino acids with a molecular weight of 38,098. The 43-kD fragment had an unusual amino acid composition based on a sequence in which the sum of Asp (28 residues), Asn (22), Glu (35), Gln (9), and Lys (52) residues accounted for more than 45% of the total. A comparison of the amino acid sequence of the 43-kD fragment with that of streptokinase did not reveal any obvious sequence homology. There was also no sequence homology with that of trypsin, -chymotrypsin, and elastase.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

Identifying the fluorescent body (F-body) with quinacrine mustard staining of canine

The fluorescent body (F-body) was identified with quinacrine mustard (Q-M) staining in spermatozoon and lymphocyte of canine. Well washed sperm suspension was treated with protease (125 mg/ml) or dispase (2000p. u./ml) and staining with Q-M (final dilution 50 micrograms/ml) for 15 min to 24 hr at 37 degrees C. The lymphocyte cultures from whole blood were prepared as routine human investigation. The chromosomal preparation made by air dry method was stained with Q-M (final dilution 0.5 to 50 micrograms/ml) after pretreatment of enzyme digestion. The examination using a reflected fluorescent microscope revealed that the same F-body in human was present in both spermatozoon (20.1-39.7%) and interphase of lymphocyte (0.37.2%) of male origin.     

Transformation of mouse BALB/c 3T3 cells with human basic fibroblast growth factor cDNA.

The expression of human basic fibroblast growth factor (bFGF) cDNA in mouse BALB/c 3T3 clone A31 cells induced morphological transformation. These transformed cells grew well and reached more than a sixfold-higher saturation density than parental A31 cells even in serum-free medium. They were able to form colonies in soft agar. The phenotypic alteration in the transformed cells was reversed by the addition of anti-human bFGF antibodies to the medium. These results suggest that the cellular transformation mediated by bFGF is caused by autocrine stimulation with secreted bFGF molecules.     

Light and electron microscopic studies on experimental nocardia-toxicosis in mice

An exotoxin (HS-6) produced by Nocardia otitidiscaviarum isolated from certain lesions of cutaneous nocardiosis of a male 82-year-old patient induced severe injuries in the pancreas, liver, stomach, small intestine, heart, thymus and kidney of male ICR mice. Mice given Nocardia-free preparation of HS-6 at a dose of 1 mg/kg of body weight developed several autophagic vacuoles in the pancreas and liver within 20 min after the i.p. injection. Thereafter, the autophagic vacuoles increased in number and size with time. About 24 hr after the administration of HS-6, the liver showed marked accumulation of fat droplets in the cytoplasm of the hepatocytes. Although they contained abundant autophagic vacuoles in the regions of RER, there were no lipomatoses in the acinar cells of the pancreas, those of the chief cells and smooth muscle cells of the stomach, Paneth cells, goblet cells, smooth muscle cells of the small intestine, and plasma cells in the digestive tract. Biochemical examinations revealed that HS-6 had no significant effect on the protein synthesis of reticulocytes. Inoculation of the Nocardia into the mouse peritoneal cavities caused marked granulomatoses in the pancreas, liver and regional lymph nodes, but did not develop autophagic vacuoles in RER regions of these organs.     

cDNA cloning of a novel heterogeneous nuclear ribonucleoprotein gene homologue in Caenorhabditis elegans using hamster prion protein cDNA as a hybridization probe.

The mammalian prion protein (PrPc) is a cellular protein of unknown function, an altered isoform of which (PrPsc) is a component of the infectious particle (prion) thought to be responsible for spongiform encephalopathies in humans and animals. The evolutionary conservation of the PrP gene has been reported in the genomes of many vertebrates as well as certain invertebrates. In the genome of nematode Caenorhabditis elegans, the sequence capable of hybridizing with the mammalian PrP cDNA probe has been demonstrated, predicting the presence of the PrP gene homologue in C.elegans. In this study, Southern analysis with the hamster PrP cDNA (HaPrP) probe confirmed the previous observation. Moreover, Northern analysis revealed that the sequence is actively transcribed in adult worms. Thus, we screened C.elegans cDNA libraries with the HaPrP probe and isolated a cDNA that hybridizes to the same sequence in C.elegans that hybridized with the HaPrP probe in the Southern and Northern analyses. The deduced amino acid sequence of this cDNA, however, is substantially homologous with heterogeneous nuclear ribonucleoprotein (hnRNP) core proteins rather than mammalian PrPc. The hnRNPs contain the glycine-rich domain in the C-terminal half of the molecule, which also seemed to be in PrPc at the N-terminal half of the molecule. Both of the glycine-rich domains are composed of tracts with high G + C content, indicating that these tracts may due to the hybridizing signals. These results suggest that this cDNA clone is derived from a novel hnRNP gene homologue in C.elegans but not from a predicted PrP gene homologue.