Chlorination of cellulose with N-chlorosuccinimide-triphenylphosphine under homogeneous conditions in lithium chloride-N,N-dimethylacetamide.

Microcrystalline cellulose was chlorinated with N-chlorosuccinimide-triphenylphosphine under homogeneous conditions in LiCl-N,N-dimethylacetamide. At the early stage of the reaction only replacement of the 6-hydroxyl groups with chlorine was observed, and 3-hydroxyl groups were replaced at a lower rate with Walden inversion. The effects of reaction conditions on the extent of chlorination were studied in detail. More than two equivalents of chlorination reagents per glucose residue were necessary to attain a high degree of substitution (ds) by chlorine, and the maximum ds attained was 1.86. Chlorinated disaccharides were found in the hydrolyzates of chlorodeoxycelluloses hydrolyzed under mild conditions, and their structures were studied by mass spectrometry.     

Purification and characterization of a novel lactonohydrolase, catalyzing the hydrolysis of aldonate lactones and aromatic lactones, from Fusarium oxysporum.

A novel lactonohydrolase, an enzyme that catalyzes the hydrolysis of aldonate lactones to the corresponding aldonic acids, was purified 10-fold to apparent homogeneity, with a 61% overall recovery, from Fusarium oxysporum AKU 3702, through a purification procedure comprising DEAE-Sephacel, octyl-Sepharose CL-4B and hydroxyapatite chromatographies and crystallization. The molecular mass of the native enzyme, as estimated by high-performance gel-permeation chromatography, is 125 kDa, and the subunit molecular mass is 60 kDa. The enzyme contains 15.4% (by mass) glucose equivalent of carbohydrate, and about 1 mol calcium/subunit. The enzyme hydrolyzes aldonate lactones, such as D-galactono-gamma-lactone and L-mannono-gamma-lactone, stereospecifically. Furthermore, it can catalyze the asymmetric hydrolysis of D-pantoyl lactone, which is a promising chiral building block for the chemical synthesis of D-pantothenate. These reactions are reversible, and the reaction equilibrium at pH 6.0 has a molar ratio of nearly 1:1 with D-pantoyl lactone and D-pantoic acid. The Km and Vmax for D-galactono-gamma-lactone are 3.6 mM and 1440 U/mg, respectively, and those for D-galactonate are 52.6 mM and 216 U/mg, respectively. The enzyme also irreversibly hydrolyzes several aromatic lactones, such as dihydrocoumarin and homogentisic-acid lactone.     

Bordetella pertussis adenylate cyclase toxin. Structural and functional independence of the catalytic and hemolytic activities.

The Bordetella pertussis calmodulin-dependent adenylate cyclase (CyaA) is a 1706-residue-long toxin, endowed with hemolytic activity. We have constructed B. pertussis mutant strains producing modified CyaAs devoid of adenylate cyclase activity. Our results show that such modified CyaAs display hemolytic activity identical to the wild-type toxin, thus demonstrating that the hemolytic activity is independent of the adenylate cyclase activity. Furthermore, B. pertussis and Escherichia coli strains producing CyaA lacking the catalytic domain (residues 1-373) were constructed. The truncated protein exhibits hemolytic activity comparable to the wild-type toxin, thus establishing that the carboxyl-terminal 1332 residues alone are endowed with hemolytic activity. Together, these findings show that adenylate cyclase and hemolytic activities are located in two distinct regions of the molecule (respectively, approximately amino acids 1-400 and 401-1706) and that the two regions of CyaA are functionally independent.     

Suppression of the development of uterine adenomyosis by danazol treatment in mice.

Inhibitory effects of danazol, an isoxazol derivative of synthetic steroid 17 alpha-ethinyl-testosterone, on the development of uterine adenomyosis, a pathological disorder of endometrial tissue defined as the presence of endometrial glands and stroma in the myometrium, were investigated in mice of SHN strain. Mice treated with 0.5 microgram danazol for 5 weeks during 4-9 weeks of age and killed at 21 weeks of age showed significantly lower incidence of the spontaneous development of adenomyosis than the age-matched intact control mice. The inhibitory effects of danazol were also evident in mice bearing pituitary isografts which were effective in inducing an early and a high incidence of adenomyosis. Furthermore, the treatment with danazol resulted in the decrease of serum levels of luteinizing hormone (LH) and prolactin (PRL) associated with hypofunction of ovaries and persistent diestrus. These results support the usefulness of danazol for the clinical treatment of gynecological disorders except for hypofunction of ovaries.     

Explant organ culture: A review

Organ explant culture models offer several significant advantages for studies of patho-physiologic mechanisms like cell injury, secretion, differentiation and structure development. Organs or small explants/slices can be removed in vivo and maintained in vitro for extended periods of time if careful attention is paid to the media composition, substrate selection, and atmosphere. In the case of human tissues obtained from autopsy or surgery, additional attention must be paid to the postmortem interval, temperature, hydration, and cause of death. Explant organ culture has been effectively utilized to establish outgrowth cell cultures and characterize the histiotypic relationships between the various cell types within an organ or tissue.J. Resau is a visiting scientist at the NCI-LMO-DCE in Frederick, MD 21702, U.S.A.K. Sakamoto is a visiting scientist from the Department of Surgery, Gunma University School of Medicine, Maebashi, Japan     

Organomercurial-volatilizing bacteria in the mercury-polluted sediment of Minamata Bay, Japan.

A total of 4,604 bacterial strains isolated from the sediments of Minamata Bay and nearby low-level-mercury stations (control stations) were screened for the ability to volatilize mercury from inorganic and organic mercurial compounds. The strains that volatilize mercury from several kinds of organomercurials were found only in the sediments of Minamata Bay.     

An extra idic(15p)(q11) chromosome in Prader-Willi syndrome

Using a nonfluorescent AT-specific oligopeptide antibiotic, Distamycin A, on DAPI fluorescent banding of human chromosome (DA-DAPI) as described by Schweizer et al. (1978), we have detected an additional idic(15p) chromosome in a patient with typical Prader-Willi syndrome. On the basis of the evidence available in previous studies and of our own present results, we suspect that the fundamental genetic error in the syndrome is not caused by a chromosome aberration but by a gene aberration on chromosome 15.     

Study of oxytocin receptor: II. Gestational changes in oxytocin activity in the human myometrium

This study was designed to investigate the oxytocin (OT) specific binding receptors in 20,000 x g pellets of nonpregnant, first trimester and term human myometria. The receptor analysis was done using the lower uterine segment at term and the lower portion of the anterior uterine body in nonpregnant and first trimester subjects, and no difference was found in the myometrial receptor concentrations in the various uteri. The mean +/- S.D. values of the receptor dissociation constants were 3.33 +/- 0.50, 2.71 +/- 1.03 and 1.87 +/- 0.30 nM and the number of binding sites was 0.30 +/- 0.10, 0.50 +/- 0.10 and 1.50 +/- 0.50 pmol/mg protein at each stage studied, indicating that the gestational increase of uterine sensitivity to OT is due to the increase in myometrial OT binding sites as well as its binding affinity. Further, myometrial OT binding before and after the onset of labor was studied and a marked decrease in total myometrial OT binding was noticed; 35.6 +/- 13.0% before and 20.2 +/- 5.0% after. This decrease was thought to be due to the decrease in the number of binding sites from 1.50 +/- 0.50 to 0.74 +/- 0.21 pmol/mg protein after the onset of labor (p less than 0.01). No changes were found in the dissociation constants. Thus it seems that OT and its receptor coupling triggers labor or is involved in the early steps of labor.