Detection of allogeneic Qa/TL and Ly specificities on murine tumor cells with IgD in tumor-regressor serum

Summary Serum from C3H/He mice, which show regression of MM2 tumor cells after transplantation and removal (regressor serum, RS) contains non-gammaglobulin components that cross-react with various tumor cells of mice [22, 23]. In addition to tumor cells, various allogeneic lymphocytes are also susceptible to an RS-dependent lymphocyte-mediated cytotoxic reaction. To identify tumor cell surface antigens that cause the cross-reactive host response, the serum components were analyzed by absorption of RS with allogeneic lymphocytes. RS components were found to recognize allogeneic lymphocyte antigens including Qa-2 and Ly6.2. Specificity for the Qa-2 antigen was further tested using Qa-2-congenic mice. The expression of Qa-2 antigen was detected on the surfaces of MM2 and other tumor cells derived from H-2^k mice (seven among nine cell lines tested) by a membrane immunofluorescence method using a Qa-2-specific mAb. Physical characteristics of the Qa-2-specific component in RS were determined and found to differ from those of regular IgGs but to be similar to those of IgDs. Using an enzyme-linked immunosorbent assay with an IgD-specific mAb and Qa-2-lacZ fusion protein, the existence of IgD in RS with specificity for Qa-2 was confirmed. These results suggest that the RS component with Qa-2 specificity is an IgD, the specificity and physiological role of which are unknown.     

Developmental expression of ascidian neurotransmitter synthesis genes

To identify cholinergic neurons, we isolated a choline acetyltransferase (Ci-ChAT) gene from Ciona intestinalis by PCR methods. In the cloning process, we also obtained the gene encoding the vesicular acetylcholine transporter (Ci-vAChTP). These two genes shared the same 5'-UTR sequence as well as similar expression patterns. In both cases, the gene expression was first detected by whole-mount in situ hybridization in the anterior-dorsal region of the caudal nerve cord at the early tailbud stage. In the larva, the expression was seen in several cells of the visceral ganglion. These results suggest that ascidian larval motor neurons exist in the visceral ganglion.     

Decision making using hybrid rough sets and neural networks

A methodology for using rough sets theory for preference modeling in decision problem is presented in this paper. We will introduce a new method where neural network systems and rough sets theory are completely integrated into a hybrid system and are used cooperatively for decision and classification support. At the first glance, the two methods we discuss have not much in common. But, in spite of the differences between them, it is interesting to try to incorporate both into one combined system, and apply it in the building of a decision support system.     

An Antifungal Constituent in Enkianthus perulatus

A new cinnamate was isolated as an antifungal constituent from young leaves and shoots of Enkianthus perulatus. The structure was shown to be 1 on the basis of the chemical and spectroscopic studies.     

Affinity separation of human plasma gelsolin on Affi-Gel Blue

Human plasma gelsolin was specifically eluted with 1 mM adenosine 5'-triphosphate from an Affi-Gel Blue column. Since the ionic strength of sodium chloride required to elute the protein from the dye column was much higher than that of 1 mM adenosine 5'-triphosphate, the binding of plasma gelsolin with the dye-ligand appeared to be biospecific. Taking advantage of this affinity interaction, we have developed a revised purification method of human plasma gelsolin. The purification included ammonium sulfate precipitation, diethylaminoethyl-Sepharose chromatography, Affi-Gel Blue chromatography, and Phenyl-Sepharose chromatography. The method allowed a reproducible purification of the protein to apparent homogeneity, producing a 331-fold purification with a yield of 6%.     

Collagenase in Stomach of Crown-of-thorns Starfish Acanthaster planci

Acetobacter pasteurianus strains IFO3283, SKU1108, and MSU10 were grown under acetic acid fermentation conditions, and their growth behavior was examined together with their capacity for acetic acid resistance and pellicle formation. In the fermentation process, the cells became aggregated and covered by amorphous materials in the late-log and stationary phases, but dispersed again in the second growth phase (due to overoxidation). The morphological change in the cells was accompanied by changes in sugar contents, which might be related to pellicle polysaccharide formation. To determine the relationship between pellicle formation and acetic acid resistance, a pellicle-forming R strain and a non-forming S strain were isolated, and their fermentation ability and acetic acid diffusion activity were compared. The results suggest that pellicle formation is directly related to acetic acid resistance ability, and thus is important to acetic acid fermentation in these A. pasteurianus strains.     

The E1 protein of human papillomavirus type 16 is dispensable for maintenance replication of the viral genome

Papillomavirus genomes are thought to be amplified to about 100 copies per cell soon after infection, maintained constant at this level in basal cells, and amplified for viral production upon keratinocyte differentiation. To determine the requirement for E1 in viral DNA replication at different stages, an E1-defective mutant of the human papillomavirus 16 (HPV16) genome featuring a translation termination mutation in the E1 gene was used. The ability of the mutant HPV16 genome to replicate as nuclear episomes was monitored with or without exogenous expression of E1. Unlike the wild-type genome, the E1-defective HPV16 genome became established in human keratinocytes only as episomes in the presence of exogenous E1 expression. Once established, it could replicate with the same efficiency as the wild-type genome, even after the exogenous E1 was removed. However, upon calcium-induced keratinocyte differentiation, once again amplification was dependent on exogenous E1. These results demonstrate that the E1 protein is dispensable for maintenance replication but not for initial and productive replication of HPV16.     

Microdetermination of unbound tryptophan in plasma by a combination of ultrafiltration and high-performance liquid chromatography

Previous methods for measuring unbound plasma tryptophan are not completely satisfactory, and therefore we have developed an improved method for this purpose. Unbound tryptophan is separated from bound tryptophan by centrifugation through Amicon ultrafiltration membrane cones in a short period (within 2 min). The first fraction of filtrate is obtained in 30 s by centrifugation at 3000g at controlled pH and is assayed with a high-performance liquid chromatography system. The first filtrate has a higher tryptophan concentration than that obtained by prolonged centrifugation. We propose that the tryptophan concentration in the first filtrate is the value nearest that of the plasma, since a change of equilibrium between bound and unbound tryptophan during the separation procedure is quite small. The method is also simple and convenient for clinical application.