Mouse lymphoma L1210 cells acquire a new cystine transport activity upon adaptation in vitro

Summary Mouse lymphoma L1210 cells maintained in vitro at a high cell density for a certain time period adapted themselves to the in vitro environment and were able to grow indefinitely. From these adapted cells, more than 30 clones were isolated. They all had much higher activity to take up cystine than the original L1210 cells, supporting a previous view that the deficiency of the cystine uptake limits the survival and growth of L1210 cells in vitro. The cystine uptake of one cloned cell line was characterized. The enhanced uptake of cystine in these cells was mainly mediated by a Na⁺-independent, saturable system and was potently inhibited by glutamate and some other anionic amino acids, but less by aspartate. Such activity of cystine uptake was not observed in the original L1210 cells. The results suggest that, upon adaptation in vitro, L1210 cells acquire a new cystine transport activity necessary for survival and growth in vitro.     

Embryonic development,larvae and juvenile of elkhorn sculpin,Alcichthys alcicornis

The eggs ofAlcichthys alcicornis were spawned in tank at the laboratory and reared for the studies of embryonic, larval and juvenile development. This species takes place entosomatic fertilization, and females spawn fertilized eggs after copulation. The eggs are demersal and adhesive, released as a clump forming a thin layer on the bottom of tank. There was no significant difference in embryonic development between this species and other oviparous teleostean species. Hatching occurred between 17 and 18 days after spawning at a mean water temperature of 8.5?C. The newly hatched larvae averaged 4.44 mm in body length (BL). The larvae attained to post-larval stage at 5.80 mm BL, and juvenile stage at 10.2 mm BL. A specific feature of the post-larvae was the appearance of three lines of the melanophores on the caudal part of fin fold. Carotenoid first appeared on the nape at 8.70 mm BL, heavily emerged beyond 12.9 mm BL, and turned up on the back also beyond 15.2 mm BL. Scales on the lateral line were completed by 18.5 mm BL. Three pairs of flaps were observed on the dorsal surface of the head at 37.0 mm BL. External features of adult specimens are almost completed by 52.0 mm BL, yet the tip of the first preopercular was not branched but remained simple.     

Isolation and characterization of the bacteriophage T4 tail-associated lysozyme.

Direct evidence has been obtained that the tail-associated lysozyme of bacteriophage T4 (tail-lysozyme) is gp5, which is a protein component of the hub of the baseplate. Tails were treated with 3 M guanidine hydrochloride containing 1% Triton X-100, and the tail-lysozyme was separated from other tail components by preparative isoelectric focusing electrophoresis as a peak with a pI of 8.4. The molecular weight as determined from sodium dodecyl sulfate electrophoresis was 42,000. The tail-lysozyme was unambiguously identified as gp5 when the position of the lysozyme was compared with that of gp5 of tube-baseplates from 5ts1/23amH11/eL1ainfected Escherichia coli cells by two-dimensional gel electrophoresis. The tail-lysozyme has N-acetylmuramidase activity and the same substrate specificity as gene e lysozyme; the optimum pH is around 5.8, about 1 pH unit lower than for the e lysozyme. We assume that the tail-lysozyme plays an essential role in locally digesting the peptidoglycan layer to let the tube penetrate into the periplasmic space. The tail-lysozyme is presumably also responsible for "lysis from without."     

Spinach nitrate reductase: purification, molecular weight, and subunit composition

Nitrate reductase was purified about 3,000-fold from spinach leaves by chromatography on butyl Toyopearl 650-M, hydroxyapatite-brushite, and blue Sepharose CL-6B columns. The purified enzyme yielded a single protein band upon polyacrylamide gel electrophoresis under nondenaturing conditions. This band also gave a positive stain for reduced methylviologen-nitrate reductase activity. The specific NADH-nitrate reductase activities of the purified preparations varied from 80 to 130 units per milligram protein. Sucrose density gradient centrifugation and gel filtration experiments gave a sedimentation coefficient of 10.5 S and a Stokes radius of 6.3 nanometers, respectively. From these values, a molecular weight of 270,000 ± 40,000 was estimated for the native reductase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the denatured enzyme yielded a subunit band having a molecular weight of 114,000 together with a very faint band possessing a somewhat smaller molecular weight. It is concluded that spinach nitrate reductase is composed of two identical subunits possessing a molecular weight of 110,000 to 120,000.     

Purification of Ribulose 5-phosphate Kinase and Minor Polypeptides of Pyrenoid from the Green Alga Bryopsis maxima

Ribulose 5-phosphate (Ru5P) kinase (ATP:D-ribulose 5-phosphate1-phosphotrans- ferase; EC 2.7.1.19 [EC] ), an enzyme in the reductivepentose phosphate cycle, was purified from the green alga Bryopsismaxima and its activity and peptide composition were studied.The specific activity of purified Ru5P kinase was 20 µmoleRuBP formed (mg protein)^–1 min^–1 corresponding toa 490-fold purification from the supernatant of chloroplasts.The K_m values of Ru5P kinase for ATP and Ru5P were 69 µMand 330 µM, respectively. The molecular size of Ru5P kinase was estimated as 90 kDa bygel filtration and that of its polypeptide as 41 kDa by SDS-polyacrylamidegel electrophoresis. A small portion of the Ru5P kinase wasfound in a large molecular state (500 kDa) which was consideredto be an inactive form of the enzyme. Ru5P kinase activity has been reported in the pyrenoid of Eremosphaeraviridis as well as ribulose 1,5-bisphosphate carboxylase-oxygenase(RuBisCO) and ribose 5-phosphate isomerase activity (Holdsworth1971). In Bryopsis maxima, among the pyrenoid polypeptides otherthan that of RuBisCO, we found a polypeptide of 42 kDa, similarto that of Ru5P kinase in molecular size and ratio to RuBisCO.A peptide map of the 42 kDa pyrenoid polypeptide, however, showedthat it differed from that of Ru5P kinase. In conclusion, Ru5Pkinase may be not involved in the pyrenoid of this alga. (Received January 19, 1985; Accepted May 15, 1985)     

Responses of pituitary and adrenal medulla to insulin-induced hypoglycemia in patients with anorexia nervosa

The responses of pituitary and adrenomedullary hormones to insulin-induced hypoglycemia were studied in 10 patients with anorexia nervosa and 7 control females of comparable age. The increases in plasma GH and PRL were significantly smaller in the patients, while the responses of GH to arginine and of PRL to TRH were indistinguishable. Plasma cortisol attained similar peak levels in both groups with higher basal levels and smaller increments in the patients. The response of plasma epinephrine was markedly lower in the patients, although urinary epinephrine showed similar increase in both groups. These results suggest the possibility that the process by which hypoglycemic stimulus causes pituitary and adrenomedullary hormone secretion is deranged in patients with anorexia nervosa.     

Responses to epinephrine in patients with anorexia nervosa

To examine the sensitivity to epinephrine in patients with anorexia nervosa, 20-60 micrograms/kg body weight/min of epinephrine was infused for 30 min each in 5 patients and 5 controls. The increase in pulse rate and the decrease in diastolic blood pressure were significantly smaller in the patient group. Elevated plasma GH levels in the patients were markedly suppressed by epinephrine infusion. These results indicate the beta-adrenergic function is decreased at least in the cardiovascular system in patients with anorexia nervosa.     

Callus formation from protoplasts of culturedSpinacia oleracea cells

Cell suspensions were initiated from plumule derived calli ofSpinacia oleracea. Some of these cell lines could be maintained in culture for at least three years without a reduced growth rate. A high yield of protoplasts was obtained from the cell suspensions. When protoplasts were cultured in Murashige and Skoog medium with naphthaleneacetic acid and 6-benzyladenine, cell wall formation was observed after three days. The cultured protoplasts produced numerous cell-clusters within two weeks. However only protoplasts isolated from suspensions which were in a rapidly dividing phase were able to divide with a high frequency and give rise to callus colonies.     

The standardization of the candidate national standard anti-D blood-typing serum with the Groupamatic MG50 system

The utility of the Groupamatic MG50 system for quantitative expression of agglutination in terms of continuous response was studied. By use of the characteristics of the design of this system, in which the change in voltage reflects the degree of agglutination, a linear regression relationship between the log ratio of light flux obtained by transformation of the voltage and the log dilution factor of the serum was demonstrated. The availability of the parallel line assay method to the standardization of the blood grouping antisera was also described.