Fat tissue: an underappreciated source of stem cells for biotechnology

Adipose tissue can be harvested in large amounts with minimal morbidity. It contains numerous cells types, including adipocytes, preadipocytes, vascular endothelial cells and vascular smooth muscle cells; it also contains cells that have the ability to differentiate into several lineages, such as fat, bone, cartilage, skeletal, smooth, and cardiac muscle, endothelium, hematopoietic cells, hepatocytes and neuronal cells. Cloning studies have shown that some adipose-derived stem cells (ADSCs) have multilineage differentiation potential. ADSCs are also capable of expressing multiple growth factors, including vascular endothelial growth factor and hepatocyte growth factor. Early, uncontrolled, non-randomized clinical research, applying fresh adipose-derived cells into a cranial defect or undifferentiated ADSCs into fistulas in Crohn's disease, has shown healing and an absence of side effects. The combination of these properties, and the large quantity of cells that can be obtained from fat, suggests that this tissue will be a useful tool in biotechnology.     

Optimal hematocrit theory during activity in the bullfrog (Rana catesbeiana).

1. There is an exponential relationship between blood viscosity (cP) and hematocrit (%) for the bullfrog; eta = 1.81 e0.033Hct. The in vitro optimal hematocrit calculated for blood flow through tubes, from this relationship for bullfrog blood, is 30%. 2. Amphibian blood is a non-Newtonian fluid with viscosity dependent on shear rate. It has a finite yield shear stress of about 1.5 dynes cm-2. 3. Hematocrit of bullfrogs was increased from 27% (control) to 57% by isovolemic erythrocythemia (constant volume blood-doping). There was a slight increase in systolic, diastolic and venous blood pressure with elevated hematocrit. 4. Systemic arch blood flow rate was inversely related to blood viscosity for erythrocythemic bullfrogs. The decrease in systemic arch blood flow at high hematocrits was due primarily to reduced pulse volume rather than reduced heart rate. 5. Systemic arch blood flow, when standardised between individuals, was inversely related to blood viscosity; Qbl = 0.185 + 3.73 eta -1. This relationship was significantly different from that predicted by the Poiseuille-Hagen flow formula. The in vivo optimal hematocrit calculated from this relationship was 41%. 6. Optimal hematocrit theory appears to be generally applicable for Rana catesbeiana in vitro and in vivo. Most individuals had an in vivo optimal hematocrit, but the absence of a clear optimal hematocrit for some individuals could reflect methodological variability, or in vivo physiological compensation for the increased blood viscosity at high hematocrit.     

Ecology of yeasts in polluted water

The general size and composition of the extant yeast populations in 13 polluted freshwater habitats were surveyed. Subsequently the yeast populations in three of the 13 locations were quantitatively determined and compared. The three locations had (A) low pollution levels, (B) heavy industrial waste pollution, and (C) heavy domestic waste pollution.The yeast population at location A was dominated byRhodotorula andCryptococcus isolates. At station BRhodotorula andCandida were predominant.Candida isolates were in the majority at location C andRhodotorula strains were second in frequency, but were much lower in proportion of the population than at the other two habitats.These polluted waters in general had large yeast populations, ranging as high as 27,000 yeasts per 100 ml, and averaging approximately 3000 yeasts per 100 ml.The presence of human wastes was especially associated with large increases in the proportion ofCandida yeasts in the environment. The genusRhodotorula was consistently present at all locations, but the genusCryptococcus was a major component of the yeast population only in non-polluted or lightly polluted fresh water.We appreciate the assistance of the Calumet Area Surveillance Program, Federal Water Pollution Control Administration, Chicago, in the collection of water samples. This investigation was supported by U.S. Public Health Service Research Grant No. AI 04642 from the National Institute of Allergy and Infectious Diseases.     

Effect of tryptophan on growth and morphology of Hansenula schneggii cells

Sundhagul, Malee (Illinois Institute of Technology, Chicago), and L. R. Hedrick. Effect of tryptophan on growth and morphology of Hansenula schneggii cells. J. Bacteriol. 92:241-249. 1966.-When Hansenula schneggii cells were cultured aerobically in a tryptophan-glucose medium, 70 to 90% of the cells were elongated; no growth occurred under anaerobic conditions. The size of the elongated cells was 15 to 25 mu by 2 to 4 mu, as compared with 2.5 to 5 mu for ellipsoidal cells. Formation of elongated cells occurred essentially during the logarithmic growth period; the highest percentage of elongated cells was found soon after the end of this growth phase. In the later stationary phase, some of the cells formed spherical buds which became spherical cells. The rate of cell division during this period was greatly reduced, but the spherical cells formed decreased the percentage of elongated cells in the population. Cells cultured in a membrane-filter filtrate of a tryptophan-glucose medium (with limiting tryptophan), in which elongated cells had been grown, were ellipsoidal until nitrogenous nutrients were exhausted; thereafter the cells were elongated if tryptophan was added. Of compounds related to tryptophan, kynurenine was the only one which induced a high percentage of the cells to elongate. Some amino acids, such as cystine, histidine, phenylalanine, tyrosine, and threonine, induced elongation in about 15% of the cells. Growth of cells with other amino acids, or the addition of most of the other amino acids to tryptophan-glucose medium, resulted in a population of spherical cells. Several consecutive sequential transfers of cells into tryptophan medium induced elongation in 90% of the cells, but one transfer from a culture with elongated cells into a medium with ammonium sulfate, or a mixture of amino acids, gave a culture with ellipsoidal cells. Growth in media at pH 4 or 5 favored formation of elongated cells; as the pH was increased, the percentage of elongated cells decreased. Carbon sources other than glucose did not affect the percentage of elongated cells, except for the alcohols mannitol and erythitol, which gave comparable growth but reduced the percentage of elongated cells from 70 to 50%. Cell wall analyses of the two types of cells indicated that elongated cells have 2.5 times as much mannan as cell walls of ellipsoidal cells. This suggests that tryptophan, kynurenine, and, to a limited extent, some of the other amino acids cause a diversion of polysaccharide biosynthesis to mannan in the elongated cells rather than to glucan as in ellipsoidal cells.     

Bufo japonicus japonicus and Xenopus laevis laevis egg jellies contain structurally related antigens and cortical granule lectin ligands

The antigenic relationship of the egg jelly coat glycoproteins from Bufo japonicus japonicus and Xenopus laevis laevis was investigated using agar double diffusion methods. The presence of ligands in the jelly coats for the cortical granule lectin from X.l. laevis eggs was also investigated. Anti-jelly serum for both anuran species crossreacted with the jelly coat from the other species with precipitin patterns of identity. Each egg jelly coat of both species contained two ligands for the cortical granule lectin. Although the ligands in the two different jelly coats appeared to react with the lectin in a pattern of identity, the species ligands were antigenically distinguishable using anti-Xenopus jelly serum. The observations that the two anuran egg jelly coats were antigenically related and that they both contained ligands for the X.l. laevis cortical granule lectin was interpreted in terms of fertilization mechanisms in the two different species. In addition, these observations bring into question the currently accepted phylogenetic relationship of B.j. japonicus and X.l. laevis.