Production of trout,Salmo trutta,in a Danish stream

Synopsis The numbers of trout,Salmo trutta, in Granslev », Denmark, were estimated by the removal method on 18 dates from March 1974 to March 1976. Populations density varied from 0.39 to 0.74 trout m^–2 in 1974–1975 and from 0.36 to 0.59 m^–2 in 1975–1976 and at all times four or five year classes were present. The age structure of the population was unstable and the variable natural survival, immigration into and emigration from the study site could not be separated. An annual growth cycle with the most rapid growth for all year classes taking place from May to early August was found. Statistically significant differences between different years occurred in the growth of the 0,I and II age groups, but no evidence of density-dependent growth was found. The biomass ranged from 35.4 to 9.5 g m^–2. The total mean annual biomass was 22.8 and 14.7 g m^–2 in the two years and the II group made the greatest contribution, 44 and 48%, respectively. During 1975–1976 the mean annual biomass of each year class only was about two-thirds of that in 1974–1975. Annual production in the two years was 25.7 (range 24.7–28.5) and 12.6 g m^–2 (range 11.7–15.0) and the II group accounted for about 46 and 38% of the production. In addition eel,Anguilla anguilla, produced about 0.5 g m^–2 yr^–2. The unstable age structure of the trout population was compared with trout populations from other streams. The importance of immigration as a recruitment process in middle and lower reaches of streams and of migrations as a mechanism to optimise utilization of the total stream habitat, as well as temperature as a factor controlling the growth rate are discussed.     

Norepinephrine Metabolism in Man Using Deuterium Labeling: Turnover of 4-Hydroxy-3-Methoxymandelic Acid

Abstract: 4-Hydroxy-3-methoxymandelic acid (HMMA; VMA) labeled with three deuterium atoms was used to study the turnover and fate of HMMA following intravenous injection. Five healthy men were given a pulse dose of 5.0 μmol of labeled HMMA. Plasma and urinary levels of both endogenous and labeled HMMA were subsequently followed by gas chromatography-mass spectrometry using selected ion detection. The kinetic parameters were determined both with and without compensation for the pool expansion caused by the injection of labeled HMMA. The urinary recovery of labeled HMMA was 85 × 10% (mean ± SD). No conversion of HMMA t o 4-hydroxy-3-methoxyphenyl glycol (HMPG) occurred. The biological half-life of HMMA was 0.54 ± 0.22 h. The apparent volume of distribution was 0.36 ± 0.11 L/kg. The production rate or body turnover was 1.27 ± 0.51 μmol HMM/h and urinary excretion rate was 0.82 ± 0.22 μmol/h. These results show that HMMA is turning over rapidly in a relatively small volume of distribution and that, unlike HMPG, it is an end metabolite of norepinephrine in man.     

Effect of serum step-down on protein metabolism and proliferation kinetics of NHIK 3025 cells

Human NHIK 3025 cells growing exponentially in 30% or 3% serum had population doubling times of 19.1 and 27.6 hours, respectively. These values were equal to the calculated protein doubling times (17.6 and 26.5 hours, respectively), showing that the cells were in balanced growth at both serum concentrations. Stepdown from 30% to 3% serum reduced the rate of protein synthesis within 1–2 hours, from 5.7% hour to 4.3% hour, while the rate of protein degradation was unchanged (1.7%/hour). In cells synchronized by mitotic selection from an exponentially growing population, the median cell cycle durations in 30% and 3% serum were 17.2 and 23.6 hours, respectively, which were also in good agreement with the protein doubling times. The median G₁ durations were 7.1 and 9.6 hours, respectively. Thus the duration of G₁ relative to the total cell cycle duration was the same in the two cases. Complete removal of serum for a period of 3 hours resulted in a 3-hour prolongation of the cell cycle regardless of the time after mitotic selection at which the serum was removed. For synchronized cells, the rate of entry into both the S phase and into the subsequent cell cycle were reduced in 3% serum as compared to 30% serum, the former rate being significantly greater than the latter at both serum concentrations. Our results thus indicate that these cells are continuously dependent upon serum throughout the entire cell cycle.     

Natural killer activity in the peritoneal exudates of mice infected with Listeria monocytogenes: characterization of the natural killer cells by using a monoclonal rat anti-murine macrophage antibody (M1/70)

Exudates induced by i.p. injection of five listeria monocytogenes (LM) constituted a rich source of CBA/J murine natural killer (NK) cells. Maximum expression of NK activity was seen from day 2 through day 6 after initial exposure to LM. When nylon wool nonadherent peritoneal exudate cells were examined by a single-cell cytotoxicity assay, the number of cells binding to YAC-1 target cells increased after infection as did their individual lytic capacity. A monoclonal rat anti-murine macrophage antibody (M1/70), previously shown by our group to recognize human NK cells, can also be used as a marker for murine NK cells. Utilizing M1/70 and the fluorescence-activated cell sorter, selection of M1/70-labeled mononuclear cells led to the enrichment of both NK and antibody-dependent cellular cytotoxicity. These M1/70-positive cells had a distinctive morphology and contained granules on Wright-Giemsa staining. They were not phagocytic, did not contain nonspecific esterase, and lacked surface I-Ak, IgM determinants, complement receptors, and high levels of Thy 1.2.     

Isolation and characterization of lambda phages carrying the basic replicon of the resistance plasmid R1

Summary Specialized transducing lambda phages, oriR1, harboring DNA from the resistance plasmid R1drd-19 and its copy mutant pKN103 were isolated. From measurements of CCC-DNA content it is concluded that upon infection the phages can establish themselves as self-replicating plasmids in recA hosts lysogenic for lambda. It is thought that this bypassing of lambda immunity is due to the presence of the R1 origin of replication. The plasmids are sensitive to the incompatibility expressed by plasmid R1. This has been shown mainly by transduction of oriR1 into recipients containing R1 plasmids or plasmid pBR322 carrying the basic replicon. We were able to demonstrate that a copy mutant of plasmid R1 was insensitive to copA ⁺, but sensitive to the conserted action of Pst1 fragments F₁ and F₂. This mutant was previously assumed to be of the dominant type. Physical mapping of the oriR1 derivatives verified that they carry the basic replicon of plasmid R1. The plasmids are not stably maintained, but are lost in a frequency of 1%–2% per cell generation, which is consistent with their lack of the R1par region.     

Summer water relations of the desert phreatophyte Prosopis glandulosa in the Sonoran Desert of southern California

Summary Two shoot populations of the rhizomatous, patchforming herb Solidago canadensis were studied throughout a developmental cycle in two abandoned pasture sites in southern Ontario. The shoot cohorts that emerged in spring dominated the two populations; subsequent recruitment was very low. Shoot mortality was highest in June and was concentrated in the smallest size classes. Both populations showed a pronounced bimodal size structure for most of the growth cycle. Relative growth rate of shoots declined as the growing season progressed and tended to be lowest in the smallest size classes. Inflorescence production depended on shoot size. The calculated relationship between log mean weight and log density of shoots was not constant during the growth cycle and the calculated maximum biomass values do not transgress the ultimate thinning line suggested from previously published data.Address for proofs and present address: Department of Geography, University of Liverpool, P.O. Box 147, Liverpool, L69 3BX. England     

ATP-levels of germinating seeds in relation to vigor

Determination of seed vigor was attempted by comparing ATP-levels of deteriorating seed to germination percentage and production of dry matter. Immediately after imbibition of any seed lot investigated, a production of ATP took place. This ATP-accumulation invariably reached a plateau after 6 h of imbibition. Two well germinating seed lots of rape, one of cauliflower and one of sugar beet, were artificially aged by means of elevated storage temperature and humidity. Every second week through 16 weeks of deterioration the levels of ATP, ADP and AMP after 7 h of imbibition were compared with the germination percentage. While ADP- and AMP-contents of germinating seed displayed no change (when imbibed 7 h) during the period of artificial aging, seed deterioration was reflected in the ATP-levels long before loss of viability could be detected by the conventional germination test.
When ATP-levels per seed were related to germination percentage throughout the aging, all four seed lots displayed similar patterns although the absolute figures differed. In contrast to the conventional "per seed' basis, however, ATP per gram seed not only displayed similar deterioration patterns, but the absolute values were also of the same magnitude.     

Lysosomal pool of free-amino acids

Free (non-protein) amino acids were measured in whole rat liver and in unmodified lysosomes which were prepared from rat liver by the technique of free-flow electrophoresis. Significant intralysosomal pools of threonine, serine, valine, cystine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine and arginine were found. No efflux occurred from rat liver lysosomes in isotonic buffered sucrose at 0°C, but all amino acids showed various degrees of efflux at 20⁰ and 37⁰.