Dental pulp collagenase: initial demonstration and characterization.

A collagenase, active against native helical collagen, was initially found in the explant medium of bovine dental pulp. In contrast to the collagenases from other oral tissues, all the pulp enzyme released was in a latent form which was activated by trypsin treatment, 4-aminophenylmercuric acetate, and some chaotropic agents. The activated enzyme was inhibited by low concentrations of EDTA and calf serum. The molecular weight of activated enzyme was tentatively estimated at 45,000 daltons by gel filtration. The enzyme attacked undenatured collagen in solution at 20°C producing characteristic products $\text{α}{}^{\mathrm{A}}\text{(}\text{3}\text{4}\text{)}$ and $\text{α}{}^{\mathrm{B}}\text{(}\text{1}\text{4}\text{)}$.     

Dielectric relaxation of DNA solutions. III. Effects of DNA concentration, protein contamination, and mixed solvents

As a continuation of previous papers [Biopolymers (1976) 15 , 879; (1978) 17 , 1508], the low-frequency dielectric relaxation of DNA solutions was studied with a four-electrode cell and the simultaneous two-frequency measurement. Below a critical concentration, the dielectric relaxation time agrees with the rotational relaxation time estimated from the reduced viscosity and is almost independent of DNA concentration C_p, and the dielectric increment is proportional to C_p. The critical concentration is approximately 0.02% of DNA for molecular weight M_r 2 × 10⁶ and 0.2% for M_r 4.5 × 10⁵ in 1 mM NaCl. Dielectric relaxations are compared for samples before and after deproteinization, and the protein contamination is found to have a minor effect on the dipole moment of DNA. The effect of a mixed solvent of water and ethanol on the dielectric relaxation of DNA is well interpreted in terms of changes in viscosity and the dielectric constant of the solvent, assuming that the relaxation arises from rotation of the molecule with a quasi-permanent dipole due to counterion fluctuation.     

Reproductive lifespan and reproductive performance in SPF C3H mice: the onset of reproductive life and production efficiency (author's transl)]

To improve the production system, the onset and the termination of reproductive life of C3Hf/HeMsNrs mice mated immediately after weaning and reared for 400 days of life, were studied. From weaning females mated with a full grown male (group A), the first litter was obtained at a mean age of 47 days, suggesting the first copulation at 26 days of age. The age of males at the first copulation was estimated to be at 44 days of age from the age giving the first litters in weanling males mated with weanling (group B) and full grown (group C) females. The sex ratio of litters delivered by young dams tended to be excess in males. The reproductive performance of dams in later life was not affected by the parturition in earlier age. The production efficiency with weaned youngs per pair during the first 200 days after mating was the highest in group A. It was found from these results that the C3H females attained their sexual maturity at 5 to 6 days after weaning, being available for breeding without any deletion in reproductive performance.     

Microbiological degradation of bile acids. The conjugation of a certain cholic acid metabolite with amino acids in Corynebacterium equi.

1. (4R)-4[4alpha-(2-Carboxyethyl)-3aalpha-hexahydro-7abeta-methyl-5-oxoindan-1beta-yl]valeric acid (II) could not be utilized by Arthrobacter simplex, even though the acid was one of the metabolites formed from cholic acid (I) by this organism. Therefore the further degradation of the acid (II) by Corynebacterium equi was investigated to identify the intermediates involved in the cholic acid degradation. 2. The organism, cultured in a medium containing the acid (II) as the sole source of carbon, produced unexpected metabolites, the conjugates of this original acid (II) with amino acids or their derivatives, although the yield was very low. These new metabolites were isolated and identified by chemical synthesis as the Na-((4R)-4-[4alpha-(2-carboxyethyl)-3a alpha-hexahydro-7a beta-methyl-5-oxoindan-1 beta-yl]-valeryl) derivatives of L-alanine, glutamic acid, O-acetylhomoserine and glutamine, i.e. compounds (IIIa), (IIIb), (IIId) respectively. 3. The possibility that the bacterial synthetic reaction observed in the acid (II) metabolism with C. equi is analogous to peptide conjugation known in both animals and higher plants is discussed. A possible mechanism for this bacterial conjugation is also considered.     

Dielectric relaxation of DNA in aqueous solutions.

Using a four-electrode cell and a new electronic system for direct detection of the frequency differences specturm of solution impedance, the complex dielectric constant of calf thymus DNA (M_r = 4 × 10⁶) in aqueous NaCl at 10°C is measured at frequencies ranging from 0.2 Hz to 30 kHz. The DNA concentrations are C_p = 0.01% and 0.05%, and the NaCl concentrations are varied from C_s = 10^?4 M to 10^?3 M. A single relaxation regions is found in this frequency range, the relaxation frequency being 10 Hz at C_p = 0.01% and C_s = 10^?3 M. At C_p = 0.05% it is evidenced that the DNA chains have appreciable intermolecular interactions. The dielectric relaxaton time τ_d at C_p = 0.01% agrees well with the rotational relaxation time estimated from the reduced visocisty on the assumption that the DNA is not representable as a rigid rod but a coiled chain. It is concluded that the dielectric relaxiatioinis ascribed to the rotation of the molecule. Observed values of dielectric increment and other experimental findings are reasonably explained by assuming that the dipole moment of DNA results from the slow counterion fluctuation which has a longer relaxation time than τ_d.     

Characterization of protein kinases from bovine parotid glands. The effect of tolbutamide and its derivative on these partially purified enzymes.

1. Four fractions of protein kinase (EC 2.7.1.37) activity (Peak IH, IIH, IIIC and IVC) have been resolved and partially purified from the 100 000 X g supernatant fraction of bovine parotid glands by DEAE-cellulose and phosphocellulose chromatographies. 2. The protein kinases of Peak IH and IIH were adenosine 3',5'-monophosphate (cyclic AMP) -dependent and had similar enzymic properties. The enzyme activities of Peak IIIC and IVC were cyclic-AMP independent, but there were some distinct differences between their properties. The protein kinase in Peak IIIC was activated by 0.2 M NaCl or KCl and phosphorylated casein preferentially as the substrate, utilizing only ATP as a phosphate donor. On the other hand, the protein kinase in Peak IVC was inhibited by univalent salts and preferred phosvitin to casein, utilizing either ATP or GTP as a phosphate donor. 3. Tolbutamide increased the Km value for ATP and the dissociation constant for cyclic AMP, resulting in the inhibition of cyclic-AMP dependent protein kinase activity in the presence of cyclic AMP. Tolbtamide and its carboxy derivative, 1-butyl-3-p-carboxyphenylsulfonylurea, exerted almost no inhibitory effect on either the cyclic-AMP dependent protein kinase activities in the absence of cyclic AMP or on the cyclic-AMP independent protein kinase activities.     

Decrease in bacterial production over the past three decades in the north basin of Lake Biwa,Japan

Limnology - In Lake Biwa, the largest lake in Japan, external pollutant loads have decreased since the 1980s, leading to improved water quality, such as reduction in biochemical oxygen demand (BOD)...     

Correction to: Comparative analysis of sperm motility in liquid and seminal coagulum portions between Bornean orangutan (Pongo pygmaeus) and chimpanzee (Pan troglodytes)

Primates - In the original publication of the article, the coauthor “Takashi Hayakawa” was wrongly assigned as co-corresponding author.     

Synthesis of 2-Alkynylcordycepins and Evaluation of Their Vasodilating Activity

Abstract

Based on the recently developed lithiation-mediated stannyl migration of 6-chloropurine derivatives, 2-iodocordycepin was prepared from cordycepin. The reaction of this compound with terminal alkynes was carried out to synthesize a series of 2-alkynyl derivatives. The vasodilating effect of these compounds was evaluated.     

Preparation of 8-Chloropurine Nucleosides Through the Reaction Between their C-8 Lithiated Species and p-Toluenesulfonyl Chloride

Abstract

Chlorination of purine nucleosides protected with tert-butyldimethylsilyl (TBDMS) group was examined by the reaction of the C-8 lithiated species, generated by LDA, with p-toluenesulfonyl chloride as an electrophile. This provides a new method for the preparation of 8-chloropurine nucleosides.