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Chymotryptic cleavage of α1-CB6, the C-terminal CNBr peptide of the α1-chain from calf skin collagen, yields three peptides, designated C1 (positions 1-113), C2 (positions 114-196) and C3 (positions 197-217), respectively. The present paper describes the amino acid sequence of C2. It was determined exclusively by application of the automated Edman degradation. The entire peptide C2 as well as some of its tryptic and thermolytic peptides were subjected to this procedure. The helical portion of α1-CB6-C2 (positions 114-192) was found to consist of tripeptide units containing glycine in every third position, hence being typical of the collagen structure. The α1-chain of calf skin collagen contains a 3-hydroxyproline residue which was located in position 164 in the tripeptide unit Gly-3Hyp-4Hyp. This is the first case of a vertebrate collagen in which hydroxylation was found of a proline in position X of the tripeptide unit Gly-X-Y. The helical part of the α1-chain terminates in a five-fold repetition of the tripeptide Gly-Pro-Pro. The four C-terminal amino acids of C2 are already part of the nonhelical area at the end of the α1-chain which in addition comprises the entire peptide C3. [ABSTRACT FROM AUTHOR]

The gycine-rich, arginine-rich histone from calf thymus contains 102 residues of amino acids, distributed as follows: Asp5, Thr7, Ser2, Glu6, Pro1, Gly17,. Ala7, Val9, Met1, Ile6, Leu8, Tyr4, Phe2, Lys10, Lys(Me)1, His2, Arg14. From a tryptic hydrolysate of Gly- and Arg-rich histone, 18 peptides were isolated by fractionation on a column of Chromobeads P followed by purification by paper electrophoresis and chromatography. The amino acid compositions of these peptides are reported. The sequence of 12 of these tryptic peptides has been established. The amino-terminal tryptic peptide is Ac-Ser-Gly-Arg. The carboxylterminal tryptic peptide is Thr-Leu-Tyr-Gly-Phe-Gly-GlyCOOH. [ABSTRACT FROM AUTHOR]

The main polypeptide chain of the lens protein α-crystallin (αA2) is N-terminally acetylated and contains two methionine residues. The chain is initiated by the incorporation of a methionine residue exclusively donated by methionyl-tRNAfMet. This N-terminal methionine is not removed during polypeptide chain synthesis. The internal methionine residue is donated exclusively by one of the methionyl-tRNAMet species. When lens messenger RNA coding for the αA2 chain is translated m a reticulocyte cell-free system, the newly synthesized polypeptide chain carries an acetylated methionine in the N-terminal position. [ABSTRACT FROM AUTHOR]

The peptide α1(78)-CBC representing the amino-terminal half of α1-CB6, was obtained from α1(78) by cleavage with CNBr. The parent peptide α1(78) can be isolated from a mixture of collagen fragments which are products of limited digestion of native collagen with bacterial collagenase. Having the amino acid sequence of the tryptic peptides, it was possible to determine their order by the use of overlapping peptides derived from partial cleavage with thermolysine. The peptide chain is characterized by regions with predominantly polar and regions with mainly apolar amino acids, the distribution of which was found in excellent correlation to the distribution of dark and light cross-striation bands of this specific part of the molecule, as depicted in long-spacing segment crystallites. The sequence of nine amino acid residues (Gly-Asp-Arg-Gly-Glu-Thr-Gly-Pro-Ala) was found twice in the elucidated peptide. Another sequence including 11 amino acid residues (Gly-Ile-Hyl-Gly-His-Arg-Gly-Phe-Ser-Gly-Leu) is identical to a sequence found in α1-CB(4-5) except m one position m which a methionine was replaced by an isoleucine. [ABSTRACT FROM AUTHOR]

The protein α-crystallin from calf eye lenses can be isolated in very high yield by zonal centrifugation. No other purification steps are required in order to obtain preparations the purity criteria of which allow sequence studies after dissociation into polypeptide chains, By this method evidence is provided that α-crystallin is a population of aggregates built up by four different polypeptide chains, occurring in an almost, constant ratio independent on the size of the aggregate. [ABSTRACT FROM AUTHOR]

When chromatin from calf thymus is treated with dilute hydrochloric acid under mild conditions variable proportions of histones become bound to the DNA, thus becoming insoluble and appearing as non-histones. This is confirmed by model experiments in which artificial mixtures of pure histones and DNA were treated with acid. The acid insoluble residual proteins formed are strongly bound (presumably covalently) to the DNA, but can be separated by density gradient centrifugation at pH 11.5. Some properties of these "non-histones" are discussed. Their amino acid analyses are different from those of the histones. The differences, also recognizable in model experiments must originate from the mild acid treatment in presence of DNA and suggest modifications of amino acids. These "nonhistones" are considered to be masked histones, because after strong alkali treatment, definite histone fractions can be recognized by electrophoreses. The conclusion is drawn that mild acid treatment of chromatin artificially produces "nonhistones". [ABSTRACT FROM AUTHOR]

The helix→coil transitions of poly-L-arginine and poly-L-lysine are compared with that of calf thymus histone, using spectroscopic methods. Although poly-L-lysine can be obtained in helical form in water by raising pH or ionic strength, this is not found to be possible with polyL-arginine. Optical rotatory dispersion data for the synthetic polypeptides indicate sharp transitions when certain organic solvents are added to aqueous solutions. Calf thymus histone by contrast shows a gradual change in helicity as organic solvents arc added. The high resolution nuclear magnetic resonance spectra of poly-L-lysine and poly-L-arginine in aqueous methanol mixtures have been obtained. The αCH peak position is found to depend on the polymer conformation and for fully helical poly-L-arginine lies at approx. 6.0 τ. [ABSTRACT FROM AUTHOR]

The present results, together with physicochemical evidence presented elsewhere, indicate that α-crystallin from calf lens is composed of two acidic and two basic polypeptide chains. The acidic polypeptides could be isolated by chromatography on SE-Sephadex at, pH 5.5 in the presence of 7 M urea. It could be demonstrated that both S-carboxymethylated acidic polypeptides are of equal molecular weight and amino add composition. In both chains N-acetylmethionyl-aspartate was found as the N-terminal and serine as the C-terminal residue. Peptide mapping reveals one unique peptide region for each polypeptide. In embryonic α-crystallin only one acidic polypeptide can be detected. From comparative amino acid analysis, peptide maps as well as physicochemical behaviour it may be deduced that the polypeptide present in the early embryonic stages is identical with the adult acidic polypeptide A-2. [ABSTRACT FROM AUTHOR]

Experiments on the vaccination of calves against Dictyocaulus viviparus infection using whole worm antigen in Freund's adjuvant are described. A reduction in the number of worms developing from a challenge infection was sometimes obtained but the method seems to be of little practical value. [ABSTRACT FROM AUTHOR]

It has been shown experimentally that infection of calves with D. viviparus confers a high degree of resistance to a subsequent reinfection. This acquired immunity can result from a single infection with a sub-lethal dose of larvae or from a series of repeated doses of small numbers of larvae. Animals immunized by a previous infection exhibit on challenge a rapid antibody response and a striking reduction (in some cases to zero) in the numbers of worms reaching the lungs, and in the numbers of larvae appearing in the faeces. [ABSTRACT FROM AUTHOR]

Intestinal immunoglobulins have been examined in secretions obtained from Thiry-Vella loops prepared in the mid-jejunum of six calves. Free secretory component and 11S IgA were demonstrated. Immunofluorescent studies of intestinal tissue confirmed the presence of a secretory IgA system similar to that described in other species. However quantitative assays showed that IgA was not at any time the predominant immunoglobulin in intestinal secretions. IgM consistently exceeded the level of IgA by approximately two-fold and its localization in lymphoid cells of the lamina propria and crypt epithelial cells suggested that IgM may normally play an important role in local intestinal defence in the calf. IgG1 appeared in consistently low levels in intestinal secretions in spite of being the major serum immunoglobulin. [ABSTRACT FROM AUTHOR]

The article presents information on the experimental autoimmune thymitis in guinea-pigs. Normal and thymectomized outbred guinea-pigs were immunized with extracts of calf thymus, calf skeletal muscle or calf heart muscle emulsified in Freund's complete adjuvant. Immunization with either thymus or skeletal muscle produced a significant incidence of thymitis and a partial neuromuscular block in contrast to control animals either untreated or injected with an extract of calf lymph node or saline in Freund's complete adjuvant. About 10% of patient shave thymomas. Of the remaining patients, the thymus is normal macroscopically and microscopically in 20% while in the other 80% germinal centers are conspicuously present in the thymic medulla.

The behaviour of rat skin collagen on collagenase treatment is analogous to that of calf skirt collagen. Fragments are also formed, but differ to a certain extent in length and amount from those by calf skin collagen. All molecular fragments consist, of only two electrophoretically separable chains, namely α1 and α2. [ABSTRACT FROM AUTHOR]

The article presents information on two research studies on topics including manganese deficiency in the etiology of deformed calves and measurement of photosynthesis in plant tissues using bicarbonate solutions. The data from the experiment conducted to elucidate the relationship of manganese to the embryonic malformation of calves suggest that feeds containing 16 ppm of manganese are inadequate for gestating heifers. It is stated that the method of measurement of photosynthesis in plant tissues using bicarbonate solutions makes it possible to measure the effect of several variables of photosynthetic rates in leaves of higher plants.