Partial purification and characterization of a factor which stimulates an increase in ornithine decarboxylase activity in the liver from tumor cell-free ascites fluid

A factor responsible for stimulating an increase in ornithine decarboxylase activity in the liver of mice was found in tumor cell-free ascites fluid of mice 3 days after inoculation of tumor cells. The factor was purified about 70-fold in 25% yield from tumor cell-free ascites fluid. As little as 1 μg of protein of purified fraction, injected intraperitoneally into normal mice, significantly increased the activity of ornithine decarboxylase in the liver. The most active preparation of the factor formed two major protein bands on analytical polyacrylamide gel electrophoresis and both these bands stained with periodic acid-Schiff's reagent. The factor was a heat-labile, alkaline-stable, acidic protein with a molecular weight of more than 300 000. It was inactivated by treatment with 10 mM dithiothreitol, 5M urea, pronase or mixed glycosidase, but was stable on treatment with DNAase, RNAase or neuraminidase.     

Lack of association and linkage between HLA and familial polyposis coli

Summary We investigated possible association of and linkage between HLA and familial polyposis coli (FPC). In 182 individuals from 66 pedigrees of FPC and 108 individuals from a normal population, HLA-A,-B, and-C antigens were determined. When the frequencies of HLA antigens in 66 unrelated patients and in normal controls were compared, no association of FPC with HLA was observed. For the linkage analysis, HLA haplotypes of 17 affected sib pairs were investigated by the affected sib pair method. The number of pairs which shared two, one, and no haplotypes identical by descent was not significantly different from the number expected with random occurrence (P>0.95). Finally, seven families were analyzed using Morton's sequential test. A maximum lod score of-0.056 at a recombination fraction of 0.4, and a lod of-3.089 at a recombination fraction of 0.05 were obtained. Therefore, there is neither an association of nor linkage between FPC and HLA.     

Exposure of Leaves of Cucumis sativus L. to Low Temperatures in the Light Causes Uncoupling of Thylakoids II. Non-Destructive Measurements with Intact Leaves

To examine the effects of chilling of leaves of cucumber (Cucumissativus L.) in moderate light on the coupling state of thylakoidsin situ, changes in fluorescence, changes in light scatteringand flash-induced changes in absorbance at 518 nm were examinedin intact leaves. After chilling of leaves at 5?C in the lightfor 5 h, the non-photochemical quenching of fluorescence, ameasure of energisation of thylakoids, was largely suppressed.The treatment also caused a suppression of light-induced changesin the light scattering by leaves, which depends on the formationof a pH gradient across thylakoid membranes. When thylakoidswere prepared by very gentle methods from the leaves chilledin the light, through a step of preparation of intact chloro-plasts,the transport of electrons from H₂O to ferricyanide was uncoupled,being insensitive to an uncoupler, methylamine. These data provide consistent evidence that the thylakoids areuncoupled in situ by the chilling of leaves in the light and,as a consequence of the uncoupling, the energisation of themembranes is suppressed. However, the decay of the flash-inducedchange in absorbance at 518 nm in leaves was not markedly acceleratedby the treatment. The thylakoids isolated from leaves chilledin the light, which were in the uncoupled state, also did notshow a rapid decay, unless an efficient uncoupler such as gramicidinwas added. These results suggest that even a considerable uncouplingof thylakoids, brought about by chilling of leaves in the light,is not sufficient to cause a marked acceleration of the decayof the flash-induced change in absorbance at 518 nm. Therefore,analysis at 518 nm is not always a sensitive method for assessingthe coupling state of thylakoids. (Received July 1, 1991; Accepted October 4, 1991)     

Effects of solute hydrophobicity and phospholipid composition on permeability of composite membranes containing phospholipids

Permeabilities of several solutes through the composite membranes containing phospholipids have been measured. They were inversely proportional to the content of the phospholipids in the membrane. Both the permeability of solutes and the degree of permeability change around the phase transition temperature of the phospholipids for the hydrophobic solutes such as n-butanol and salicylamide were larger than those for the hydrophilic solutes such as amino acids and pyridoxine. These results suggest thatthe permeation path of hydrophobic solutes is different from that of hydrophilic ones. The addition of phosphatidyl ethanolamine, phosphatidyl serine, or phosphatidic acid to the composite membrane influenced the solute permeability due to the introduced negative charge and/or the change in the molecular packing of phospholipid.     

Permeabilities of composite membranes containing phospholipids

Two types of artificial membranes containing a phospholipid were prepared and their permeabilities were measured around the phase-transition temperature of the phospholipid. The permeability of the membranes to a hydrophobic solute was higher than to a hydrophilic solute, and showed an abrupt change at the phase-transition temperature of the phospholipid, similar to that in biomembranes and liposomes, caused by the fluidity change of the phospholipid at this temperature.     

Serologic dissection of HLA-D specificities by the use of monoclonal antibodies

To study the gene products of the HLA complex, we produced two monoclonal antibodies, termed HU-18 and HU-23. They were active in complement-dependent cytotoxicity and detected B-cell alloantigens encoded by a locus (or loci) linked to HLA. When three types of HLA-DR4 homozygous B-cell lines with different HLA-D specificities were tested for reactivity with HU-18 and HU-23, they displayed distinct reaction patterns depending on the HLA-D specificities they possessed: EBV-Wa (HLA-DYT homozygous), negative for both HU-18 and HU-23; KT2 and KOB (HLA-DKT2 homozygous), positive only for HU-18; and ER (HLA-Dw4 homozygous), positive for both. These differential reaction patterns were further confirmed by testing against a panel of 17 HLA-DR4-positive peripheral blood lymphocytes with known HLA-D specificities. Thus, these monoclonal antibodies allow us to identify HLA-DYT, HLA-DKT2, and HLA-Dw4 solely by serologic methods. This is the first clearcut serologic identification of these three HLA-DR4-associated HLA-D specificities, which have been indistinguishable by conventional serology and identified only by cellular techniques. It is hoped that immunochemical investigations using HU-18 and HU-23 will advance our understanding of the HLA-D region on a molecular level.     

Kinetics of microbial cell growth

As a rate equation of microbial cell growth, the Monod equation is widely used. However, this equation cannot fully correspond to real courses of microbial cell growth in many batch cultivations. Especially, predicted values based on this equation do not agree with observed values in many continuous cultivations. In this paper, which introduces new concepts of critical concentration and coefficient of consumption activity, the growth rate equation which corresponds to the whole period including lag period is newly derived and characteristics of microbial cell growth in batch cultivation are clarified. Further, applying the new rate equation to continuous cultivation, a general equation with which to calculate cell concentration is derived and characteristics of microbial cell growth in continuous cultivation are clarified. The calculated values of cell concentration based on the new theory showed quite good agreement with the observed values in both batch and continuous cultivation.     

Cause for dark, chilling-induced inactivation of photosynthetic oxygen-evolving system in cucumber leaves

Effects on oxygen evolution of the storage of detached cucumber (Cucumis sativus) leaves at 0°C in the dark were investigated with thylakoids and oxygen-evolving photosystem II membranes isolated from stored leaves. The cold and dark treatment of leaves selectively inactivated electron transport on the oxidizing side of photosystem II. Photosystem II membranes isolated from treated leaves were largely depleted of two proteins of 20 and 14 kilodaltons, which correspond to the extrinsic 23- and 17- kilodalton proteins of spinach functioning in oxygen evolution. The manganese content of photosystem II membranes was also markedly reduced by the treatment. Thus, the inactivation of oxygen evolution induced by the dark, chilling treatment is ascribed to solubilization of the 20- and 14-kilodalton proteins and extraction of manganese.     

Effect of testosterone on the susceptibility of C57BL/6 mice to infection with Brugia pahangi with reference to inflammatory cell response

Effects of testosterone on the susceptibility and inflammatory cell responses of C57BL/6 mice infected intraperitoneally with Brugia pahangi larvae were examined. On day 15 postinfection, female mice showed significantly greater resistance than did males, and peritoneal cell responses (lymphocytes, macrophages, and eosinophils) were great in females. Castration of highly susceptible male mice increased their resistance and peritoneal cell responses to the level of female mice; whereas, castration of female mice did not affect the susceptibility and cell responses. Furthermore, testosterone treatment at a physiological dose in the castrated male mice or a pharmacological dose in female mice suppressed resistance and inflammatory cell responses. These results suggest that male sex hormone, testosterone, but not female sex hormone has a regulatory role in the susceptibility and cellular response of C57BL/6 mice to infection with B. pahangi, and it causes differences between sexes in susceptibility.