Acetylene reduction by nitrogen-fixing blue-green algae

Summary Known nitrogen-fixing species of blue-green algae are capable of reducing acetylene to ethylene, but acetylene is not reduced by Anacystis nidulans, which does not fix nitrogen. Cycad root nodules which contain blue-green algae as endophytes reduce acetylene. Acetylene reduction is inhibited by carbon monoxide. Nitrate or ammonium-nitrogen has no immediate effect on algae reducing acetylene, but algae grown on nitrate-nitrogen gradually lose their capacity to reduce acetylene. Nitrate-nitrogen also inhibits heterocyst formation in these algae and there is a fairly direct correlation between the abundance of heterocysts in a particular sample and its capacity to reduce acetylene. Aphanizomenon flosaquae reduces acetylene and fixes nitrogen in unialgal culture and there is strong presumptive evidence that these reductions are carried out by the alga rather than by associated bacteria. The molar ratios of ethylene: ammonia produced vary within the range 1.4–1.8.     

The existence of a second route for the transfer of certain glycoproteins from the circulation into the liver.

Oligosaccharide chains of agalactoorosomucoid, α₁-acid glycoprotein from which sialic acid and galactose have been sequentially removed, terminate in N-acetylglucosaminyl residues. This protein is rapidly transferred from the circulation into the liver by a route distinct from that previously demonstrated for a number of galactosyl terminating glycoproteins.     

Effect of slide projections and tape-recorded suggestions on thermal biofeedback training

A previous experiment (Herzfeld & Taub, 1977) demonstrated that slide projections and explicit suggestions relating to thermal experiences can significantly augment temperature self-regulations training (.5 degrees F, p less than .05). however, the experimental design was thought to result in an underestimate of the magnitude of the effect, since each subject served as his own control and could therefore make use on nonsuggestion training days of material provided on training days. In this experiment, separate groups of subjects either were given feedback combined with the suggestion procedure on each of 8 training days or were given feedback alone. The mean temperature self-regulation of the suggestion group (2.01 degrees F) was significantly better than the self-regulation (.73) of the nonsuggestion group (t test, p less than 0.01), a difference of 1.28 degrees F.     

Partial purification and characterization of a gelatin-specific protease from the culture media of human pulmonary alveolar macrophages

A gelatin-specific protease from the culture media of human pulmonary alveolar macrophages has been partial purified by gel filtration and characterized. The macrophages were obtained by bronchopulmonary lavage from the lungs of disease-free smoking volunteers. The gelatin-specific protease initially requires trypsin activation. After chromatographing the culture media on a Sephadex G-200 column, trypsin is no longer required for activation. The gelatin-specific protease reported here shares many properties of previously reported gelatinases. It is inhibited by EDTA, cysteine, dithiothreitol and serum. It is unaffected by other protease inhibitors: phenylmethylsulfonyl fluoride, tosyllysine chloromethyl ketone and p-chloromercuribenzoate. Of all substrates tested activity was observed only with gelatin. It was inactive toward collagen, elastin and methemoglobin. This enzyme may have a role in the digestion of collagen which has been cleaved by a mammalian collagenase.     

Muscle and femoral vein temperatures during short-term maximal exercise in heart failure

Core temperature decreases throughout short-term maximal exercise in heart-failure patients. To investigate possible causes for this unusual response to exercise, we studied core (pulmonary arterial blood), femoral vein, muscle, and skin temperatures in eight patients with severe heart failure who performed maximal upright incremental bicycle exercise to 50 W. A normal group (n = 4) was exercised for comparison. In the heart-failure patients, core temperature was 36.95 +/- 0.37 degrees C at rest, significantly (P less than 0.05) decreased at 25 W of exercise to 36.59 +/- 0.40 degrees C, and at 50 W remained decreased to 36.57 +/- 0.40 degrees C. In comparison, we found that the resting core temperature in the normal subjects was 37.28 +/- 0.34 degrees C, was the same at 25 W (37.29 +/- 0.41 degrees C), and increased significantly (P less than 0.05) to 37.50 +/- 0.32 degrees C at 50 W of exercise. Femoral vein temperature in heart-failure patients (n = 6) was below core temperature throughout exercise to 25 and 50 W (36.22 +/- 0.62 and 36.34 +/- 0.65 degrees C, respectively). Muscle temperature (n = 7) was significantly (P less than 0.05) lower in the heart-failure patients (34.8 +/- 1.1 degrees C) at rest compared with the normal subjects (36.2 +/- 1.0 degrees C). During exercise, muscle temperature increased above core temperature in only four of the heart-failure patients and was significantly (P less than 0.05) lower (36.5 +/- 1.3 degrees C) compared with the normal subjects (38.0 +/- 0.2 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)