Differences in the renal handling of pancreatic and salivary amylase in the rat.

Plasma activity and excretion of pancreatic (P) amylase in the rat was found to be negligible. In contrast, the excretion rate of salivary (S) amylase was substantial and variable, depending on diuresis. P-amylase had a higher isoelectric point, a greater sieving coefficient, and a shorter half-life than S-amylase. A bolus injection of 125I-labelled enzymes was followed by the appearance of 125I-labelled enzyme- as well as protein-free 125I activity in the urine. The enzyme loss was smaller and the fraction of protein-free 125I activity higher following injection of P-amylase. The affinity of P-amylase to paraffin oil exceeded that of S-amylase in partition experiments with water and paraffin oil in vitro. It is concluded that both renal filtration and reabsorption of P-amylase exceed those of S-amylase. This might be due to the higher lipophility of P-amylase in comparison to the salivary type.     

Sugar and phosphate metabolism and alkaloid production phases in submerged cultures of two Claviceps strains

Summary In submerged cultures of Claviceps sp. CP II, elymoclavine was synthesized only by the growing mycelium (phase P1), whereas cultures of C. purpurea strain 129 produced agroclavine after vegetative growth had also ceased (phase P2). In strain CP II, the peak of activity of malate dehydrogenase, glucose-6-phosphate dehydrogenase and phosphatases was related to the time of maximum growth rate and alkaloid production. Citrate synthase activity paralleled the course of alkaloid synthesis. Strain 129 exhibited a further activity peak of the same magnitude during phase P2. ATP levels in both cultures corresponded to the pattern of change in enzyme activities. Strain CP II contained roughly twice as much orthophosphate and ATP in its cells as strain 129 and exhibited higher average activity of glucose-6-phosphate dehydrogenase. It follows from these results that alkaloid synthesis requires the processes of primary metabolism, even when it occurs after active growth of the culture has ceased. Cultures producing alkaloids oxidized at C-8 exhibit higher glucose-6-phosphate dehydrogenase activity, probably because of a higher NADPH consumption.     

Human T-cell cultures with selective autotumor reactivity

Summary T-cell cultures derived from the blood of 14 patients with solid tumors were propagated with T-cell growth factor (TCGF). The cultures were initiated from lymphocytes exposed to autologous tumor-biopsy cells. TCGF was added either immediately or 3–10 days later. In the former culture type the cell yield on day 7 was considerably higher. The cytotoxic potential of the cultured cells was assayed on two occasions, between days 7 and 10 and between weeks 5 and 8. Cells of all but two cultures had the potential to lyse autologous tumor-biopsy cells.On the population level, cytotoxicity was specific for autologous tumor in those cultures that were driven to growth with TCGF after the 3rd day. These lymphocytes did not lyse allogeneic tumor-biopsy cells. In contrast, all five cultures initiated in the presence of TCGF exhibited a broader cytotoxic potential, i.e., in addition to the stimulator autologous-tumor cells, they also lysed other targets. Another difference between the two culture types was their behavior toward K562. Tested on the 7th day they all lysed K562; however, this function declined in strength or disappeared later in the cultures exposed to TCGF after the 3rd day.Reexposure of the lymphocytes to autologous tumor-biopsy cells after 2 weeks of culture period, but not on the 7th day, induced DNA synthesis. This secondary response was specific inasmuch as allogeneic tumor cells had little or no effect.One of the autotumor restimulated cultures was tested for cytotoxic potential. It increased against the autologous but not against other tumors or K562 cells.     

Deletion of 13q in two patients with retinoblastoma,one probably due to 13q- mosaicism in the mother

Summary We examined the peripheral blood chromosomes of eight patients with retinoblastoma. In two of them an interstitial deletion of 13q was found. The breakpoints were determined as follows: case 1, 13q1221; case 2, 13q1231. In both cases, band 13q14 was deleted. In case 2 the lymphocytes of the mother showed the identical interstitial 13q deletion in 3 of 100 mitoses, thus raising the possibility of maternal origin of the 13q deletion in a child. In one patient, retinoblastoma was unilateral; in the other, bilateral. Both patients were mentally retarded.     

Effects of light,phosphate, and oxygen on ethylene formation and conidiation in surface cultures ofpenicillium cyclopium westling

Penicillium cyclopium growing in a surface culture with 2-ketoglutarate or glutamate as a sole carbon source produced ethylene in two phases. The first peak of ethylene production (EP 1) was associated with aerial mycelium growth whereas the second peak of ethylene production (EP 2) occurred with formation and maturation of conidia. Conidiation was induced by blue light between 120 and 172 h after the culture was started and depended on the presence of a carbon source at the stage of conidiophore initiation. Exogenous phosphate content dropper rapidly before the onset of conidiation. The EP 2 was connected with conidiation via this drop. Addition of phosphate prior to the conidiophore initiation and during conidiation inhibited EP 2 without affecting conidiation, but conidia lacked a green pigment and their germination ability decreased by 905. Exogenous ethylene did not restore normal development. The EP 2 in asporogenic cultures was evoked by incubation in the dark and by phosphate removal. The EP 2 and conidiation were accompanied by an increased oxygen consumption. The EP 1 yield of ethylene depended only on biomass growth and was unaffected by any treatment mentioned above.     

The bull shark (Carcharhinus leucas) and largetooth sash (Pristis perotteti) in Lake Bayano,a tropical man-made impoundment in Panama

Synopsis The Río Bayano in eastern Panama is one of many tropical rivers in which bull sharks (Carcharhinus leucas) and largetooth sawfish (Pristis perotteti) have been known to occur. Since both species can osmoregulate in fresh water throughout life, theoretically, both could survive in landlocked situations for many years.P. perotteti reproduces in fresh water, butC. leucas ordinarily does not, so only the former would appear to have the potential for establishing a breeding stock in such a landlocked freshwater body.The damming of the Rio Bayano and the creation of a large impoundment in 1976 provides a test of the ability of members of both species trapped there to survive and to establish breeding stocks. In 1980 and 1981 three mature femaleC. leucas were found dead in Lake Bayano and three sub-adult femaleP. perotteti were taken by trammel net. These events confirm the ability of both to survive in fresh water for long periods, but the establishment of breeding stocks appears doubtful and the question may not be answered for many years.     

Specific recognition of the neuronal cell surface by an antiserum raised plasma membrane preparations of immature rat cerebellum

A brain specific antiserum was prepared by immunizing rabbits with a crude membrane fraction from 8-day old rat cerebella. In immunofluorescence studies the antiserum labeled the perikarya and processes of cultured cerebellar neurones. In contrast, other cell types, encountered in cerebellar cultures including astrocytes, endothelial cells and fibroblasts, were consistently unstained. The antiserum when used in crossed immunoelectrophoresis with Triton X-100 solubilized brain extracts reacted predominantly with one antigen that could be identified as the D2 protein.This paper is dedicated to Dr. Derek Richter on his seventy-fifth birthday.     

Basic electrophysiological parameters and frequency sensitivity of the ventricular myocardium of human embryos

The basic electrophysiological manifestations of the ventricular myocardium of twelve 7- to 12-week human embryos were measured with a glass electrode and a programmed stimulation technique. The resting membrane potential value was 79.37 +/- 0.34 mV and the overshoot 32.7 +/- 0.57 mV; the action potential (AP) duration at 1 Hz stimulation frequency was 120.0 +/- 5.7 ms at AP plateau phase levels and 258 +/- 17 ms at the level corresponding to 95% repolarization. The duration of the AP was a function of the stimulation frequency. i.e. it altered in correlation to the stimulation programme fully developed frequency sensitivity). In stimulation with different frequencies the duration of the steady state AP was in an inverse relation to the stimulation frequency, the maximum changes being found in the terminal repolarization zone. An interpolated extrasystole mainly affected the duration of the plateau phase.     

Effect of changed cultivation conditions on the morphology ofAspergillus niger and on citric acid biosynthesis in laboratory cultivation

Cultivation ofAspergillus niger 97A in baffled flasks on a shaker brings about metabolic changes demonstrated in increased citric acid biosynthesis, morphological changes and alterations in the mycelial cell wall.