Purification and characterization of a protein that binds to the recombination signal sequence of the immunoglobulin J kappa segment.

A protein that binds to the recombination signal sequence (RS) of the immunoglobulin J kappa segment was purified almost to homogeneity from the nuclear extract of a murine pre-B cell line 38B9. A similar binding protein was found in lymphoid cell lines but not in non-lymphoid cell lines. The binding activity was associated with a polypeptide with a molecular weight of 60,000. DNase I footprinting analysis demonstrated that this binding protein interacted with the heptamer and several 3' bases close to the heptamer. The Kd value of the J kappa RS binding protein to the J kappa RS was 1 nM. One base substitution in the heptamer of the J kappa RS greatly reduced the affinity of the J kappa RS binding protein. The high specificity of the binding site of the J kappa RS binding protein suggests that this protein may be involved in V-J recombination.     

Proluminal movement of 3H-androgen across the epididymal epithelium in the rat after hypophysectomy and gonadotropin supplementation

The effects of hypophysectomy and gonadotropin replacement on transepithelial movement of 3H-androgen in the rat epididymis were examined by in vivo microperifusion of 3H-testosterone followed by in vivo micropuncture to obtain peritubular and intraluminal fluid. In the caput epididymidis of normal rats, intraluminal 3H-androgen concentrations were approximately 300% of those in the interstitial space. In contrast, proluminal movement of 3H-androgen into rat caput epididymal tubules was significantly decreased 10 days after hypophysectomy. 3H-Testosterone movement across the caput epididymal epithelium was completely returned to normal by supplementation with 24 micrograms/day follicle-stimulating hormone (FSH) or 24 micrograms/day luteinizing hormone (LH). However, neither 0.12 micrograms/day FSH nor 250 micrograms/day prolactin returned proluminal androgen movement to normal. It is speculated that epididymal uptake of peritubular testosterone is mediated by androgen-binding protein, which is known to be secreted by Sertoli cells after stimulation by FSH or testosterone.     

Primary structure of an N-linked sugar chain derived from glucoamylase of Rhizopus niveus

The primary structure of the N-linked sugar chain of Rhizopus niveus glucoamylase (major component) was investigated. The carbohydrate moiety was released from the polypeptide backbone by Flavobacterium sp. endo-beta-N-acetylglucosaminidase digestion. Studies using the method of exoglycosidase digestion of the fluorescent pyridylamino derivative, gel-permeation chromatography on Bio-Gel P-4 and 400-MHz 1H-NMR spectroscopy revealed that the most abundant structure is (Man)8-GlcNac-ol.     

Variation of glycosaminoglycan in the growth of transplantable tumors derived from a spontaneous ddY mouse mammary tumor

The components and variations of glycosaminoglycan (GAG) in the growth of transplantable tumors derived from a spontaneous mouse mammary tumor were investigated. A 45-week-old ddY female mouse, obtained from Shizuoka Laboratory Animal Center, was found to have a bean-sized mass at the third mammary gland of the left side. The tumor mass was surgically excised and used for transplantation in the present study. This mammary tumor was histologically found to be Type B-adenocarcinoma. Transplantable mammary tumors consisted of the fibrous or edematous interstitium contained a large amount of GAG components, which was mainly hyaluronic acid (HA), dermatan sulfate (DS) and chondroitin sulfate A/C (ChS). In the analysis of GAG components, HA content was present in a large amount in logarithmic growth phase of transplanted mammary tumors, but it was markedly decreased in stationary phase. On the other hand, the contents of DS and ChS increased in stationary phase of the tumor growth, and these increases corresponded, histologically, with the propagation of the fibrous interstitial tissues.     

Pathology of spontaneous malignant fibrous histiocytoma in a Japanese white rabbit

Spontaneous malignant fibrous histiocytoma (MFH) of the chest wall was found in a 10-year-old male Japanese white rabbit. Histologically, the MFH consisted mainly of areas of storiform, pleomorphic and myxoid patterns. Positive reactions for acid phosphatase (Ac-P), non-specific esterase (N-SE) and beta-glucuronidase (beta-GL) were demonstrated in fibroblast-like, histiocyte-like and giant cells. Moreover, a strongly positive fibronectin (FN) reaction was observed mainly in histiocyte-like and giant cells. In electron microscopy, tumor cells were composed morphologically of various types of cells such as fibroblast-like, histiocyte-like, undifferentiated and giant cells. This case was quite similar to those reported in man or other animals.     

Development of nephrotic ICGN mice--the origin, reproductive ability, and incidence of glomerulonephritis

ICGN is a strain of spontaneous nephrotic mice with nonproliferative glomerular lesions. It was derived from an outbred Yok: ICR colony in our laboratory. The renal disease constantly occurred in animals of the first to the tenth generations (greater than 13.0%; 70 days of age). When affected males were mated with unaffected females, the incidence of the disease in their offspring was 38.8% (n = 49) at 70 days after birth. When both parents were affected, their offspring were all affected (n = 12). The disease evenly progressed in both sexes. It usually began 40 to 150 days after birth and death occurred within two months after onset. The animals usually showed sufficient reproductive ability as long as unaffected females were used for mating.     

Involvement of prostaglandin-induced proteins in the inhibition of herpes simplex virus replication

Cyclopentenone prostaglandin (PG), delta7-PGA1 was found to induce several polypeptides in human embryonic fibroblast (HEF) cells which were noticed to be dose-related and appeared after 1 h of treatment with a peak at around 5 h and gradual disappearance after 12 h. PG-induced proteins were almost identical in terms of molecular weights with those induced by heat-shock at 42 degrees C. Regarding the mechanism of inhibition of herpes simplex virus (HSV) replication by PG in cell culture, dot blot hybridization has revealed that the level of immediate early (IE) mRNA of the virus was reduced after PG treatment with time dependence. And this delayed inhibitory effect of delta7-PGA1 on HSV was shown to be associated with the production and accumulation of the induced polypeptides.     

Evidence that chromium is an essential factor for biological activity of low-molecular-weight, chromium-binding substance

Biologically active Low-molecular-weight, chromium-binding substance (LMCr) has been isolated from the liver of rabbits injected with potassium bicarbonate and cow's milk. This substance enhances glucose oxidation and lipogenesis from glucose in rat adipocytes [Yamamoto A. et al. (1987) Eur. J. Biochem. 165, 627-631; (1988) J. Nut. 118, 39-45]. LMCr was shown to lose its activity almost completely as an effectant of glucose metabolism when Cr was deleted under acidic conditions and separated from LMCr by EDTA-chelation and successive molecular-sieve chromatography. Reincorporation of Cr3+ into apo-LMCr resulted in 50-90% recovery of its original activity. These findings suggest that the biological activity of LMCr resides in Cr.     

Effect of pH on giant cell formation induced by human immunodeficiency virus ( HIV )

The rate of multinucleated giant cell formation by the fusion of HIV chronically infected human T-cells (MOLT-4/HIV) and HIV uninfected MOLT-4 cells was examined under various pH conditions. The number of giant cells formed under the different pH conditions was quantitatively monitored by "MULTISIZER". The rate of giant cell formation was significantly less at the pH lower than 6 but not influenced at higher pH. Plaque assay under various pH conditions revealed that inhibition of giant-cell formation at lower pH was not due to the influence over the recognition between gp120 of HIV and CD4 molecules.