Reactive extraction of penicillin G from mycel-containing broth in a countercurrent extraction decanter

Penicillin was recovered from mycel-containing fermentation broth by direct reactive extraction into a counter-current extraction decanter, Type CA 226-290 of the Westfalia Separator Co., at room temperature via steady state operation. Penicillin concentrations in the feed varied from 3 to 41 g L(-1), Amberlite LA-2 carrier concentrations from 7 to 20 g L(-1)and/or DITDA carrier concentrations from 7.2 to 84 g L(-1), the LA-2-to-penicillin mole concentration ratio from 4 to 6.4, and/or the DITDA-to-penicillin mole concentration ratio was maintained at 2. The throughputs of the fermentation broth (520 to 880 L h(-1)) of the solvent phase (200 to 860 L h(-1)) and the over all throughput (800 to 1750 L h(-1)) were high. Extraction degrees of 72 to 96% were achieved between pH 4.6 and 5.1. Without carriers in the same pH range, extraction degrees of only 17 to 19% were attained. By reducing the pH to 2.3 and in the absence of carriers, the degree of extraction was increased to 61%. However, during the extraction, 6.5% of the penicillin decomposed. At these high throughputs, the steady state was attained within 1 to 4 min. Through the mechanical stress, the length of the hyphae was reduced and the protein content of the broth was increased by 50 to 100%. However, this protein content had no appreciable influence on the phase separation.     

Inhibition of lymphocyte activation with anti-transferrin receptor Mabs: a comparison of three reagents and further studies of their range of effects and mechanism of action

Prior work has suggested that Mabs against the transferrin receptor (ATRAs) may function as selective inhibitors of lymphocyte activation and that T cell activation protocols may be more sensitive to ATRA-mediated inhibition than B cell activation protocols. New side-by-side functional comparisons of three ATRAs are presented. When these studies are considered with our prior work they demonstrate unambiguously that although one particular IgG ATRA consistently fails to inhibit LPS responses and although IgM ATRAs may be slightly more effective inhibitors than IgG ATRAs, ATRAs as a class consistently appear to abolish the MLR at submicrogram concentrations, essentially eliminate cytotoxic cell generation at concentrations between 1 and 5 micrograms/ml, and produce no more than about 50% inhibition of LPS responses at concentrations as high as 25 micrograms/ml. Therefore, an even stronger case can now be made for the idea that lymphocyte subsets differ in their dependence on transferrin receptor function during activation. This, in turn, makes an even stronger case for the idea that lymphocyte subsets differ in fundamental aspects of the management of their iron economies. New studies also show that IgG ATRAs appear to function by causing down-modulation of surface expression of the transferrin receptor in normal lymphocytes in a manner similar to that previously shown for tumor cells. It is clear that a sophisticated model will ultimately be required to account for all of the data arising from studies with ATRAs, and a new attempt at a more detailed construct is presented.     

Sarafotoxin receptors mediate phosphoinositide hydrolysis in various rat brain regions

Sarafotoxin-b, a potent snake vasoconstrictor peptide homologous to the mammalian endothelial vasoconstrictor endothelin, induces phosphoinositide (PI) hydrolysis in various brain regions of the rat. Sarafotoxin-b induced PI hydrolysis is largely independent of extracellular Ca2+ and is detected in all brain regions where toxin-binding sites are found. These results point to the existence of a hitherto undetected neuroreceptor associated with the PI cycle.     

The 8p-syndrome

A partial de novo deletion of 8p in a 10 1/2 month-old boy is described, the karyotype being 46,XY,del(8) (p21.3-qter:). Reduced birth weight, growth and psychomotor retardation, craniofacial dysmorphism with microcephaly and low set, deformed ears, stubby nose, wide set nipples, congenital heart defect and undescended testes were the main clinical findings. Death occurred at 2 1/2 years of age due to fulminant tracheo-bronchitis. Red cell glutathion reductase activity was normal. A review of previous cases with similar deletions outlines a definite clinical entity.     

Reparative regeneration of microvascular anastomosis

Dynamics of reparative regeneration of the sutural anastomosis of the abdominal aorta has been studied in 90 white mice during the time from 1 day up to 1 year. The operation has been performed by means of microsurgical technique. Histological, histochemical, electron microscopic and radioautographic (3H-thymidine and 3H-uridine labelling) methods have been used. By the 7th day fibrin is organized on the adventitia, the scar along the resection line is formed, endothelial lining and middle layer of the vascular wall are restored. As sources of regeneration in the anastomosis serve cellular elements preserved in the lesion margins. Further maturation of the formed structures and formation of the initial thickening by migrating smooth muscle cells of the middle layer take place. Completeness and typicity depend on preservation of the elastic carcass in the middle layer and adventitia.     

15N-labeled 5S RNA. Identification of uridine base pairs in Escherichia coli 5S RNA by 1H-15N multiple quantum NMR

Escherichia coli 5S RNA labeled with 15N at N3 of the uridines was isolated from the S phi-187 uracil auxotroph grown on a minimal medium supplemented with [3-15N]uracil. 1H-15N multiple quantum filtered and 2D chemical shift correlated spectra gave resonances for the uridine imino 1H-15N units whose protons were exchanging slowly with solvent. Peaks with 1H/15N shifts at 11.6/154.8, 11.7/155.0, 11.8/155.5, 12.1/155.0, and 12.2/155.0 ppm were assigned to GU interactions. Two labile high-field AU resonances at 12.6/156.8 and 12.8/157.3 ppm typical of AU pairs in a shielded environment at the end of a helix were seen. Intense AU signals were also found at 13.4/158.5 and 13.6/159.2 ppm where 1H-15N units in normal Watson-Crick pairs resonate. 1H resonances at 10.6 and 13.8 ppm were too weak, presumably because of exchange with water, to give peaks in chemical shift correlated spectra. 1H chemical shifts suggest that the resonance at 13.8 ppm represents a labile AU pair, while the resonance at 10.6 ppm is typical of a tertiary interaction between U and a tightly bound water or a phosphate residue. The NMR data are consistent with proposed secondary structures for 5S RNA.     

Interaction of calcium and vanadate with fluorescein isothiocyanate labeled Ca2+-ATPase from sarcoplasmic reticulum: kinetics and equilibria

The interaction of Ca2+ and vanadate with fluorescein isothiocyanate (FITC) labeled sarcoplasmic reticulum (SR) Ca2+-ATPase has been studied by following the kinetics of changes in the reporter group fluorescence and equilibrium fluorescence levels. The vanadate species bound to the enzyme is clearly monomeric orthovanadate, probably H2VO4-. Vanadate binding is noncooperative, suggesting an absence of interactions between the Ca2+-ATPase subunits. The fluorescence experiments confirm the existence of a calcium-enzyme-vanadate complex (in the presence of magnesium). On the basis of the fluorescence properties of this complex, it is similar in its conformation to the calcium-enzyme complex, i.e., "E1-like" rather than "E2-like". However, Ca2+ binds to the enzyme-vanadate complex via sites that are only accessible from the interior of the SR vesicles. The complex Ca2E*Van, which is rapidly formed, isomerizes very slowly (t1/2 approximately 1 min) to the stable ternary complex. The mutual destabilization between bound vanadate and two bound Ca2+ ions is only 1.6 kcal/mol, much smaller than that produced by the interaction of calcium and phosphate.     

Zinc-dependent angiotensin-converting enzyme in reactions with various enzymes

The effects of Zn2+ on the activity of the angiotensin-converting enzyme from bovine lung towards the substrates, FA-Phe-Gly-Gly and Cbz-Phe-His-Leu, have been studied. At pH below 7.0 zinc ions added to the reaction mixture increase the enzyme activity; this stimulating effect is changed to inhibition with a further rise in Zn2+ concentration. It was shown that the dissociation constant for the enzyme--Zn2+ complex and the "optimal" concentrations of Zn2+ needed for the manifestation of the maximal enzymatic activity depend on the nature of the substrate at all pH values studied.     

Peptides related to the active fragment of "proline rich polypeptide", an immunoregulatory protein of the ovine colostrum. Spectroscopic and computer modeling studies

The preferred solution conformation of the PRP-hexapeptide (Tyr-Val-Pro-Leu-Phe-Pro) and of some of its structural analogues was investigated by NMR-spectroscopy, spectrofluorimetry and computer simulation technic. It was found that the preferred conformation is characterized by cis'-conformation of Pro3 and the gamma-turn on the Leu4-residue: for Val2 and Phe5 a beta-structure seems to be privileged. In such a conformation Val2 and Leu4 residues occupy exactly the same positions in space as residues i and i + 3 in an alpha-helix. It suggests that the PRP-hexapeptide can interact with receptor protein inducing or stabilizing its helical conformation by "knobs into holes" packing.     

3H]prostaglandin uptake in vivo by rabbit uterine tissues and blastocysts

Day-6 pregnant rabbits were anesthetized and subjected to a mid-ventral laparotomy. [3H] Prostaglandin F2alpha) (PGF2alpha) [3H]PGE2, [14C]Urea or [14C]Sucrose were instilled into the uterine lumen via the uterotubal junction. The amounts instilled/uterine horn were respectively 3.7 +/- 0.3, 3.5 +/- 0.3, 5.7 +/- 1.3 and 2.7 +/- 1.6 muCi in 20mul of buffer. Animals were killed at 1, 2, 9, 19 or 21 h after radioactive instillation, and the amounts of radioactivity in blastocysts, uterine tissue, peritoneal cavity washings and urine evaluated by liquid scintillation spectrometry. A gradient of radioactivity was observed from the uterotubal junction to the cervical end of the uterus. Large amounts of [3H]PG were found in the injected horn and associated blastocysts with a considerable crossover to the non-injected horn, but little in the associated blastocysts. Much of the blastocysts associated- [3H]PG remained unmetabolized. Large amounts of metabolized [3 H] were found in urine. [14C]Urea was taken up by uterine tissue in the injected horn, but there was little cross over to the non-injected horn. Urea was also found in urine. Much of the [14C]Sucrose remained in the injected horn, and little was recovered from the urine. It was found that at 9 h, but not at 19 h, after [3 H]PG instillation, the PG was localized at the site of the blastocysts in the injected but not in the contralateral horn. Significantly more [3H]PGF2alpha than [3H]PGE2 was localized in this situation. [14C]Urea was not localized at the site of the blastocysts in urea injected horns. (ABSTRACT TRUNCATED AT 250 WORDS)