An antiserum to the C-terminus of the Alzheimer amyloid precursor recognizes a soluble 70 kDa protein

A rabbit antiserum to the C-terminus of the putative brain amyloid precursor was used to probe Western blots of tissue proteins separated by SDS-PAGE. The antiserum specifically labelled a protein of approx. 70 kDa in the Tris buffer-soluble fraction of brain samples from rat, Alzheimer subjects, cases of young and old Down's syndrome, and age-matched controls. The 70 kDa protein was present in low concentrations in human liver and kidney, and was undetectable in human skeletal muscle. The 70 kDa protein may be a metabolite of the amyloid precursor.     

Chromosomal genes essential for stable maintenance of the mini-F plasmid in Escherichia coli

We have isolated mutants of Escherichia coli which do not support stable maintenance of mini-F plasmids (delta ccd rep+ sop+). These host mutations, named hop, were classified into five linkage groups on the E. coli chromosome. Genetic analyses of these hop mutations by Hfr mating and P1 transduction showed their loci on the E. coli genetic map to be as follows: hopA in the gyrB-tnaA region, hopB in the bglB-oriC region, hopD between 8 and 15 min, and hopE in the argA-thyA region. Kinetics of stability of the sop+ and delta sop mini-F plasmids in these hop mutants suggest that the hopA mutants are defective in partitioning of mini-F rather than in plasmid replication. The hopB, hopC, and hopD mutants were partially defective in replication of mini-F. The physical structure of the plasmid DNA was normal in hopA, B, C, and D mutants. Large amounts of linear multimers of plasmid DNA accumulated in mutants of the fifth linkage group (hopE). None of the hop mutations in any linkage group affected the normal growth of cells.     

Chemical characterization by protein sequence analysis of the bovine estrogen receptor

Tryptic peptides generated from bovine estrogen receptor have been fractionated and purified using microbore column high performance liquid chromatography. Sequence analysis performed on six of these peptides, derived from diverse structural regions of the receptor protein, yielded 73 unique assignments corresponding to approximately 12% of the molecule. The amino acid sequences of these peptides displayed a high degree of similarity with corresponding sequences from estrogen receptors of mammalian origin, but were only moderately conserved in receptors from non-mammalian species. The sequenced residues of one tryptic peptide, positioned in the estrogen binding domain, were fully conserved in all estrogen receptors.     

Oxidation of lipids. XV. Role of hydrophilic diarylamines as antioxidants in the oxidations of lipids and biological tissues

The abilities of two kinds of water-soluble diarylamines, disodium 4-chloro-2,2'-iminodibenzoate (CCA) and disodium 4-chloro-3',6'-dimethyl-2,2'-iminodibenzoate (CCM), to protect lipids, membranes and biological tissues from oxidative damages have been studied. The experimental systems studied include the oxidations of methyl linoleate micelles and soybean phosphatidylcholine (Pc) liposomal membranes in aqueous dispersions, oxidative hemolysis of rabbit erythrocytes, and the in vivo oxidative damages of biological tissues all induced by free radicals generated from an azo radical initiator. The two diarylamines functioned as moderate chain-breaking antioxidants and retarded the above oxidations.     

Studies on the role of transferrin and endocytosis in the uptake of Fe3+ from Fe-nitrilotriacetate by mouse duodenum

Addition of iron-binding proteins (human serum transferrin, mouse serum transferrin, human lactoferrin) to the luminal fluid in tied-off segments of mouse intestine in vivo led to reduced 59Fe3+ absorption from 59Fe3+-nitrilotriacetate when compared to 59Fe3+-nitrilotriacetate alone. Assay of transferrin in luminal fluid from tied segments revealed only trace amounts of immunoreactivity. The levels of luminal transferrin are unaltered in chronic hypoxia where iron absorption is significantly enhanced. Studies in vitro revealed that NH4Cl, dansylcadavarine, para-chloromercuribenzoate and trinitrobenzenesulphonate have no effect on initial 59Fe3+ uptake rates from 59Fe3+-nitrilotriacetate, while N-ethylmaleimide (1 mM) caused a 40% inhibition. In vivo 59Fe3+ uptake was unaffected by preincubation of tied-off segments with colchicine (5 mM) for up to 2 h. These results suggest that receptor-mediated endocytosis of transferrin is not a significant mechanism in the uptake of luminal Fe3+ by mouse duodenum.     

Regulation of cytochrome P-450c by glucocorticoids and polycyclic aromatic hydrocarbons in cultured fetal rat hepatocytes

The actions of polycyclic aromatic hydrocarbons and glucocorticoids to regulate the synthesis of cytochrome P-450c (the major isozyme induced by polycyclic aromatic hydrocarbons) were investigated in fetal rat hepatocytes maintained in primary monolayer culture. Treatment of hepatocytes in culture with 1,2-benzanthracene resulted in a 50-fold increase in 7-ethoxycoumarin O-deethylase activity. The level of P-450c increased in the cells in a time-dependent fashion as determined by immunoelectrophoretic analysis. The inductive effect of BA was potentiated approximately 1.6- to 2.3-fold when 1 microM dexamethasone was included in the culture medium. However, dexamethasone alone had little or no effect on the induction of P-450c. The rate of synthesis of P-450c was examined by immunoisolation of the specific isozyme from total cellular proteins radiolabeled with [35S]methionine and from the protein products formed during in vitro translation of the isolated mRNA. In addition, the amount of mRNA specific for cytochrome P-450c was determined by Northern blot analysis of RNA extracted from cultured cells. The changes in the rates of synthesis and mRNA levels were found to parallel the changes in enzyme activity. The concentration of dexamethasone required to cause a half-maximal increase in P-450c content in the presence of 1,2-benzanthracene was between 10(-8) and 10(-7) M. It is concluded that glucocorticoids act synergistically with polycyclic aromatic hydrocarbons to increase the levels of P-450c expressed in the fetal rat liver, and that this action is likely mediated by the classical type II glucocorticoid receptor.     

A comparison of the escape behaviors of the cockroaches Blaberus craniifer and Periplaneta americana

A comparison of wind-mediated escape behavior of two species of cockroaches revealed striking differences. In contrast to Periplaneta americana, Blaberus craniifer was unable to escape from a live predator or move away from a synthetically generated puff of wind. Other behavioral differences included degree of preference for areas of low light intensity and propensity to dig and thus bury oneself when disturbed. Anatomical differences, although present, did not seem sufficient to account for the behavioral differences. Also, B. craniifer was able to escape from generated wind puffs but not a live predator when its temperature was raised. These points suggest that the behavioral differences in escape behavior can be attributed to differences in the physiological state of the two nervous systems.     

The insulin-like growth factor, somatomedin C, induces the synthesis of cholesterol side-chain cleavage cytochrome P-450 and adrenodoxin in ovarian cells

The actions of insulin and somatomedin C (insulin-like growth factor I) on cholesterol side-chain cleavage activity and the synthesis of cytochrome P-450scc and adrenodoxin were investigated in primary cultures of swine ovarian (granulosa) cells. Nanomolar concentrations of pure human somatomedin C stimulated biosynthesis of progesterone and 20 alpha-hydroxypregn-4-en-3-one. Moreover, in the presence of exogenous sterol substrate for cholesterol side-chain cleavage, somatomedin C significantly enhanced pregnenolone biosynthesis in a time- and dose-dependent manner. This augmentation of functional cholesterol side-chain cleavage activity was accompanied by a dose-dependent (2-16-fold) increase in [35S]methionine incorporation into specific immunoprecipitable cytochrome P-450scc and adrenodoxin. Micromolar concentrations of insulin (but not proinsulin or desoctapeptide) also induced synthesis of cholesterol side-chain cleavage constituents by 4-7-fold. These results demonstrate that an insulin-like growth factor, somatomedin C, exerts discrete differentiating effects on ovarian cells characterized by increased synthesis of immunospecific cytochrome P-450scc and adrenodoxin. Thus, we infer that somatomedin C may serve a critical role in the differentiation of steroidogenic cells in the mammalian ovary.     

An outbreak of staphylococcal dermatitis in laboratory mice

An epizootic of dermatitis with erosion, ulcer and crust broke out in an experimental colony of JCL-ICR mouse over a period from December 1975 to June 1976. The disease was detected in 592 of a total of 1831 mice of 3-24 months old, especially in males of 7-24 months old (517/821). At the beginning of December 1975, only a few males of 12 months old were found to have the lesion on the back skin, and thereafter the dermatitis prevailed gradually among the mice. Histopathologic examinations showed the loss of the epidermis, necrosis and/or collapse of the corium, accumulation of serous exudate with neutrophilic cell infiltration and a few cocci scattered on the surface. In chronic cases, fibrous granulation tissues with neutrophilic cell infiltration were formed in the corium. Staphylococcus aureus was isolated in pure culture from the skin lesions in all of the mice examined. Skin disease similar to that of the field case was reproduced in mice inoculated subcutaneously with 10(7) viable organisms of the fresh isolate. By giving chlortetracycline in drinking water for 7 days, treatment of the affected mice was efficacious in mild cases, but not in severe cases.     

Biological properties, phage typing and antimicrobial susceptibility of Staphylococcus aureus isolated from dermatitis in laboratory mice

The characteristics of 167 isolates of S. aureus from 106 mice suffering dermatitis were examined. All 167 isolates coagulated both rabbit and human plasmas and 161 of them also coagulated bovine plasma. All the isolates produced heat-stable and heat-labile DNase, phosphatase and yellow pigment, reduced nitrate, hydrolysed egg yolk, Tween 80, and hippurate, and grew on crystal violet agar in colonies of the negative type C and on medium with 10% NaCl. The majority of them produced fibrinolysin, protease and acetoin. Fifty-three percent were gelatinase positive. In hemolysis tests, 25, 57 and 45 isolates showed alpha-, beta-, alpha beta-hemolysis, respectively. Forty isolates did not produce hemolysins in the rabbit and sheep blood agar. All of 75 isolates tested produced acid from fructose, galactose, glucose, glycerol and mannose, but did not from arabinose, dextrin, inulin, raffinose, salicin, sorbitol and xylose. Most of these isolates produced acid from lactose, mannitol, sucrose and trehalose. All of the 75 isolates were highly sensitive to penicillin, methylphenylisoxazolyl penicillin, erythromycin, spiramycin, lincomycin, chloramphenicol, tetracycline, kanamycin, gentamicin and cephaloridine, but were resistant to sulfisoxazole. With phages of human set, all 167 isolates were typable at 100 X RTD. All but one of the typable isolates belonged to mixed lytic groups. These were I + III (35 isolates), I + M (1), I + III + M (124) and I + II + III + M (6), with long phage patterns. When the 167 isolates were biotyped as described by Hájek and Marsálek [7, 8], 5 belonged to biotype A, 1 to biotype B and 60 to biotype C.(ABSTRACT TRUNCATED AT 250 WORDS)