Artturi Ilmari Virtanen 1895-1973

Professor A. I. Virtanen, the world-famous Finnish biochemist, died on November 11th, 1973 at the age of 78. He was born in Helsinki on January 15th, 1895. In his obituary professor Matti Kreula outlines the life and work of professor Virtanen dwelling in particular on the many aspects of his research and teaching activities at the time when he was professor both at the University of Helsinki and Helsinki University of Technology as well as Head of the Academy of Finland. Among the numerous academic distinctions and honorary memberships, medals and honorary prizes granted to professor Virtanen, the Nobel prize in chemistry which he was awarded in 1945 should be singled out

On the amino acids in the urine of dairy cows fed urea as the sole or partial source of nitrogen

The urinary amino acids in free and bound form were determined quantitatively in dairy cows fed urea and ammonium nitrogen as the sole (0-cows) or partial (ULP-cows) source of nitrogen. For comparison, amino acid determinations were performed also on the urine of cows on ordinary silage-cereals feed and pasture feed (NorP-cows). The total amount (mg/1 urine) of the free amino acids was the smallest with 0-cows and the highest with NorP-cows on pasture feeding. The difference was mainly due to glycine ,which was found in significantly higher (P < 0.001) amounts with NorP-cows on pasture feeding. The proportion of glycine in the total identified free amino acids was 9.7 ± 9.0 % with 0-cows, 13.5 ± 5.1 % with ULP-cows, 7.7 ±3.4 % with NorP-cows on indoor feeding and 56.4 ±21.0 % with NorP-cows on pasture feeding. The corresponding figures for glutamic acid, which was quantitatively the most important amino acid with 0- and ULP-cows, were 36.5 ± 29.6 %, 19.8 ± 19.2 %, 5.7 ±4.0 % and 3.9 ± 2.1 % of the total free amino acids. Besides the identified amino acids, there were a number of unidentified amino acid derivatives in the free amino acid fraction in all the feeding groups. The total amount of amino acids freed by hydrolysis was the lowest with 0-cows. The proportion of glycine of the amino acids of the hydrolysate was48 % with 0-cows, 66 % with ULP-cows and 84 % with NorP-cows

Aspects of the metabolism of 14C-labelled compounds by cows on a protein-free feed with urea and ammonium salts as the sole source of nitrogen

In the feeding experiments performed at the Biochemical Research Institute with test cows (the so-called 0-cows) the biosynthesis of milk component from different energy sources and from urea used as the nitrogen source was studied. The basic idea was to elucidate the effect of various feed components and substances formed in rumen fermentation on the biosynthesis of milk components. In the studies preparations labelled with 15N and 14C were used. The feed of the test cows did not contain protein at all, the carbohydrates were hexose-based and fat in the form of oil was used very scantily. All the proteins required were synthesised by test cows in symbiosis with their rumen microbes from ammonium nitrogen which they obtained from urea and ammonium salts. Protozoa disappeared gradually from the rumen and the number of bacteria increased, becoming many tens of times the number in normally-fed cows. Of the substances labelled with 14C, stearic acid and acetic acid had the highest incorporation into the different milk components. Stearic acid is transferred to milk fat almost solely as such, but apparently is used for the formation of oleic, linoleic and linolenic acids as well. Acetic acid also is incorporated mainly into fat, though it is transferred in considerable amounts also to the other milk components. Propionic acid is by nature gluconeogenetic and butyric acid lipogenic. The carbon of sucrose and lactic acid is incorporated fairly evenly into the various milk components. The studies suggest that there are only very small amounts of aromatic compounds in 0-cow tissues. According to the relative retention times the components of milk are synthesised from the different energy sources at various rates. The syntheses of citric acid and lactose are the most rapid, those of protein and fat the slowest. The feeding has a marked effect on the composition of the milk fat. On the basis of these experiments, the far-developed urea feeding does not seem to have any pronounced effect on the participation of the substances studied in the biosynthesis of milk

Studies on the sulfur metabolism of cows on protein-free and low-protein feed

The influence of purified, protein-free feed with urea and ammonium salts as nitrogen sources (0-feed) and of non-purified, urea-rich, low-protein feeds (ULP-feed) on the sulfur metabolism of cows has been studied by determining the contents of sulfur fractions in faeces, urine, milk, blood and rumen fluid. The sulfur of 0-feed was composed entirely of inorganic sulfate. During balance trials the N:S ratio in the feed varied from 6.1 to 9.5, and the sulfur content from 0.22 to 0.31 % of the dry matter. In every trial (seven with 0-feed and two with ULP-feed), of five or seven days duration, the cows were in high-positive sulfur balance. The 0-cows excreted a greater proportion of their total sulfur output via urine than the ULP-cows. The excretion of inorganic sulfate sulfur, as a proportion of the urinary and faecal sulfur, was greater for 0-cows than for ULP- or NorP-cows (cows on normal, protein-rich feed); the opposite was the case with regard to the excretion of ester sulfate sulfur and neutral sulfur. The sulfur contents of milk and blood showed only minor inter-feed differences. The sulfate content in the rumen fluid of the 0-cow rose rapidly after the commencement of feeding and then fell quite rapidly. We conclude tentatively that in the rumen of the 0-cow hydrogen sulfide is generated so quickly that the whole of it cannot be used for the synthesis of sulfur-containing compounds, a considerable proportion of it being lost in eructations or excreted as inorganic sulfates in the urine

Rehujen rikkipitoisuuksista

Rehujen rikkitilanteen selvittämiseksi on eri puolilta Suomea satunnaisesti valituilta maatiloilta määritetty ruohoista (60 näytettä), säilörehuista (857 näytettä), heinistä (125 näytettä), kauroista (40 näytettä) ja ohrista (40 näytettä) kokonaisrikki ja osasta näytteitä myös sulfaattirikki. Lisäksi on Jokioisten Lintupajun koetilalta määritetty rikki 55 säilörehunäytteestä, 36 ruohonäytteestä ja 21 näytteestä säilörehuja, joiden säilöntäaineet ovat sisältäneet rikkiä. Koko maan ruohonäytteet ovat sisältäneet rikkiä 0.16 ± 0.04 %, säilörehut 0.14 ± 0.05 % ja heinät 0.09 ± 0.01 % kuiva-aineesta. Lintupajun ruoho on sisältänyt rikkiä 0.20 ± 003 % ja siitä tehtysäilörehu 0.18 ± 0.03 % kuiva-aineesta. Kun säilörehut on tehty rikkiä sisältävillä säilöntäaineilla, on rehun keskimääräinen rikkipitoisuus ollut 0.48 % kuiva-aineesta. Säilörehujen osalta on todettu eroavuuksia maan eri osien välillä. Kauranäytteiden kuiva-aineesta on ollut rikkiä 0.07 % ja ohranäytteiden 0.06 %. Typen ja rikin keskimääräinen suhde on ollut ruohossa 19.1, säilörehussa 18.1 ja heinässä 17.8. Rikkiä säilöntäaineessa käytettäessä on typen ja rikin suhde säilörehiussa ollut 6.5. Kaurassa on typen ja rikin suhde ollut keskimäärin 30.0 ja ohrassa 35.0

Studies on the nitrogen compounds of the faeces of dairy cows fed urea as the sole or partial source of nitrogen

The nitrogen compounds of the faeces of dairy cows on purified, protein-free feed with urea and small amounts of ammonium salts as the sole source of nitrogen (0-feed). on low-protein feed in which part of the protein was replaced with urea (ULP-feed) and on normal protein-containing feed (NorP-feed) were studied. The total nitrogen contents of the dry matter of the faeces were 2.5 ± 0.7 % on 0-feed, 2.4 ± 0.4 % on ULP-feed and 2.3 ± 0.6 % on NorP-feed. The proportion of urea- and ammonium nitrogen of the total nitrogen was 3.2 ± 2.4, 4.5 ± 2.4 and 3.7 ± 1.8 % respectively, and the proportion of nitrogen soluble in 70 % ethanol 10.9 ± 5.7, 9.9 ± 2.4 and 10.4 ± 3.8 % of the total nitrogen; the proportion of nitrogen in the free amino acid fraction was 4.1 ±2.9 on 0-feed, 1.6 ± 1.4 (P < 0.05) on ULP-feed and 3.2 ± 2.9 % on NorP-feed. The nitrogen insoluble in 70 % ethanol as a proportion of the total nitrogen was 82.3 ± 7.2 on 0-feed, 85.4 ± 5.0 on ULP-feed and 82.3 ± 7.2 % on NorP-feed. Of the total nitrogen of this insoluble fraction, the following proportions were released as amino acids by acid hydrolysis: 62.15 ± 8.5 % on 0-feed, 61.6 ± 10.7 % on ULP-feed and 59.0 ± 13.9% on NorP-feed. (α, Ɛ-diaminopimelic acid was 1.7 ± 0.6, 0.7 ± 0.2 (P < 0.05) and 1.2 ± 0,4 mol % respectively of the total amino acids of the hydrolyzate. The soluble nitrogen fraction was separated into free amino acid and »peptide» fractions, and the amino acid composition of both was determined, the latter after acid hydrolysi

On the formaldehyde content of the silages prepared with formaldehyde-containing preservative

The free formaldehyde contents of 180 samples of silages preserved with »Viherliuos» were measured during the indoor-feeding period 1975-76. The mean formaldehyde content of the silages was 120 (range 20-500) and 59 (range 10-1250) mg/kg fresh weight respectively in autumn 1975 and spring 1976

Urinary nitrogen compounds in dairy cows fed urea as the sole or partial source of nitrogen

Urinary nitrogen compounds were determined in test cows with urea as the sole (0-cows) or partial (ULP-cows) source of nitrogen. An average of 0.49 % total nitrogen was found in 0-cows and 0.88 % in ULP-cows, the values for urea nitrogen being 2.24 and 2.63 mg/ml, for ammonium nitrogen 0.14 and 0.09 mg/ml, for creatinine 0.77 and 0.90 mg/ml and for creatine 0.28 and 0,42 mg/ml urine, respectively. Differences between the two groups were highly significant (P < 0.001) as regards total nitrogen and significant (P < 0.05) as regards urea nitrogen and creatine. In each group the between-cow differences were highly significant with regard to total and urea nitrogen and creatine, and in 0-cows also with regard to ammonium nitrogen and creatinine. Smaller amounts of urinary allantoin and larger amounts of uric acid were found in 0-cows than in ULP-cows. Corresponding determinations were made to some extent also on the urine of cows on normal indoor or pasture feeding

Incorporation of 15N and 14C into amino acids of bacterial and protozoal protein in the rumen of the cow on urea-rich feed

The utilization of the non-protein nitrogen and carbon of feed by rumen microorganisms for the synthesis of protein was studied by administering [U-14C] sucrose and 15NH4Cl to a cow on urea-rich, low-protein feed. By studying the labelling of the protozoa and bacteria and the amino acids isolated from them at intervals up to 48 hours afterwards, it was found that the bacteria synthesized amino acids from nonprotein nitrogen much more rapidly and effectively than the protozoa. Also the labelling of the carbon in the amino acids of the bacteria was more rapid than in the protozoa. In both protozoa and bacteria there was intracellular storage of [14C] sucrose. Of the bacterial amino acids the most vigorous 14C labelling was found in Glu, Arg, Lys, Val and Ala and the weakest labelling in Gly, His and Ser. Of the protozoal amino acids Ala, Asp, Glu, Leu and Lys had the highest labelling and Pro, Gly, His and Phe the lowest. In the bacterial protein the labelling of Pro and Arg was ten times that of the corresponding protozoal amino acids, and Asp, Ser and Ala four times. After the 15NH4Cl dose the half-life of 15N in the rumen fluid was estimated to be 3.3 h. Labelled ammonium nitrogen was about 11 —15 % of the bacterial nitrogen and 2—3 % of the protozoal nitrogen after 1 h. Of the protozoal amino acids Ala, Glu, Val, Asp and Met had the most vigorous labelling, and of the bacterial amino acids Glu, Asp, Ser, He and Tyr. The slowest incorporation of ammonium nitrogen was into His, Pro, Arg and Gly in both bacteria and protozoa. The labelling of the bacterial amino acids was approximately 7—8 times more vigorous than that of the protozoal amino acids. The labelling of Ala was only 4 times, and that of Val, Met and Glu 5 times more vigorous than with protozoal protein. The pathway of histidine synthesis seemed to be restricted in both bacteria and protozoa and therefore may be a limiting factor in protein synthesis, particularly in cows fed urea as the sole source of nitrogen. Of the 14C and 15N label given, 12.9 and 9 % respectively was secreted in the milk during the first 3 days; over the same period the 14C and 15N excreted in the faeces plus urine accounted for 16.9 and 44.3 % respectively of that administered

The effect of sulphur deficiency and sulphur fertilisation on the nitrogen compounds of timothy

The effect of sulphur deficiency and sulphur fertilisation on the nitrogen compounds of plants was studied, using timothy as the test species. The samples were obtained from 4 field trials performed in northern Finland. The nitrogen and sulphur treatments in each of these trials were as follows: a) N O, S O, b) N 48, S O, c) N 48, S 34, d) N 96, S O and e) N 96, S 68 kg/ha. Nitrogen was applied as NPK compound fertiliser and sulphur in the form of gypsum. In trials 1and 2 sulphur given in addition to nitrogen increased the yield considerably. The contents of soluble-, protein-, a-amino-, ammonium- and nitrate-nitrogen, as well as the free and peptide- and protein-bound amino acids were determined in the harvested timothy. Nitrogen fertilisation did not have any noticeable effect on the protein-nitrogen content of sulphur-deficient plants, but sulphur fertilisation increased it by an average of 26 % (trial 2). The proportion of soluble nitrogen of the total nitrogen in trials 1 and 2 averaged 50 % with N-fertilisation and 37 % with N+S fertilisation. Sulphur fertilisation decreased the contents of a-amino-, ammonium- and nitrate-nitrogen, and also their proportions of the total nitrogen. In those trials (3 and 4) in which sulphur fertilisation did not increase the yield, the proportion of soluble nitrogen of the total nitrogen was an average of 33 % with all treatments. In sulphur-deficient timothy the content of asparagine and aspartic acid totalled 60 % of the content of free amino acids, and their nitrogen formed about 17% of the total plant nitrogen. The corresponding figures with sulphur fertilisation were 39 % and 3.5 %, and in those trials where there was no sulphur deficiency (trials 3 and 4) on average 27 % and 2.5 %, irrespective of fertilisation. The proportion of soluble nitrogen of the total nitrogen of timothy was closely correlated (r = 0.79***) to the N/S ratio, as was the proportion of asparagine plus aspartic acid of the total free amino acids (r = 0.91***)