ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02343.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02344.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.A fully defined medium aside, also one with acid‐hydrolyzed casein, both pH 6.2–6.4 permitted survival ofTetrahymena pyriformis(syngen 1, mating type II) for no more than a week at 0.5 C, despite fortification with crude soy lecithin. Lecithin had permitted prolonged survival in crude media (pH 7.2), probably due largely to its phytosterols and antioxidants. Metal imbalances appeared responsible for the poor survival in defined media because additional citrate, histidine or Fe permitted monthlong survival. Al or Ni in the presence of increased citrate were also favorable. The casein‐hydrolysate medium and a fully defined medium, both fortified with lecithin, and with additional citrate or Fe, permitted survival at 0.5 C for at least 2 months. Krebs‐cycle intermediates, uridine, thymidine, adenosine, and guanosine acted as growth substrates in nearly carbohydrate‐free media, which suggests trial of their survival‐promoting properties for cold‐stored cultures. Parallels are noted for survival in the cold betweenTetrahymenaand erythrocy

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02345.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Allopurinol, 4‐hydroxypyrazolo[3,4‐d] pyrimidine, a relatively non‐toxic xanthine‐oxidase inhibitor used to treat gout, inhibited growth (ID0–901.0 μg/ml) of the trypanosomatid flagellate of insectsCrithidia fasciculatain minimal media in respect to biopterin, folic acid and purine. Allopurinol inhibition was antagonized by thymidine (4.0 μg/ml) whena) biopterin (≥ 1.0 ng) was present alone; traces of folate entering from the inoculum or contamination of chemicals probably sufficed here to satisfy the folate requirement;b)biopterin (5% pure) 1.0 ng was added together with either pteroylglutamic acid (PGA) 4.0 ng or hypoxanthine 0.01 mg. With biopterin absent, full growth was permitted by PGA 10 ng + hypoxanthine 0.03 mg, and completely inhibited by the standard concentration of allopurinol, but in this instance thymidine did not release the inhibition.Allopurinol is therefore useful for investigating pteridine function via inhibition analysis with the singularity that folate acts uniquely in trypanosomatids as precursor of biopterin, and the complication that both pteridines catalyze multiple biosyntheses. The biosynthetic step between folate and biopterin is postulated to be a site of inhibition of allopurino

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02346.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.An amoeboflagellate isolated from common soil is described. The amoeboid stage is typically limax and contains a well differentiated uroid region. The flagellate has 2 flagella, which emerge anteriorly and are equal in length. It has a ventral cytostome near the anterior border. The cyst is helmet‐shaped and without opercula. Polar masses are present during nuclear divisio

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02347.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.This paper is a brief account of both amicronucleate and sexually active strains ofTetrahymena pyriformisand their distribution with some comments on their possible evolution.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02348.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.A number of protozoa may have amoeboid, flagellated, or intergrade forms. At the present time several mechanisms have been proposed for inducing the formation of each of the above forms, but a definite triggering mechanism has not been elucidated. However, some change in the environment precedes the transformation of the cell from one form to another.Jahn (1962) and Czarska (1964), respectively, correlated ciliary reversal and water expulsion vesicle activity with alterations in the ionic environment. In both cases the processes involved are correlated with changes in the Gibbs‐Donnan (G‐D) relationship rather than direct ratios or molarities. It seems reasonable to assume that additional environmentally induced phenomena may also be based on changes in the relationship.The assumption is here made that an amoeboid cell, possessing the necessary genetic and physiologic potentials, can respond to certain changes in its environment by enflagellation.The following hypothesis is being considered: a change in the environment that increases the relative concentration of associated divalent cations is perhaps one of the main triggers for amoeba‐to‐flagellate transformations. Thus, in accordance with the G‐D theory, this transformation would be expected to occur when a given ionic environment is diluted. In addition, the transformation is discussed in relation to pH, population density, and other environmental parameters that alter the Gibbs‐D

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02349.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Autoradiographic technics with tritium‐labeled thymidine have been used to determine G1, S, G2 and D for the kinetoplast and the nucleus ofCrithidia fasciculataat 15, 25 and 32 C. The kinetoplast completes division before the nucleus at all 3 temperatures. The S phases of both organelles occur in approximate synchrony and are approximately equal in length but the nucleus begins and completes S before the kinetoplast at the 2 lower temperatures. This relationship is reversed at 32 C. Most of the effect of temperature on generation time is due to its effect on the length of S.The results are compared with similar studies onC. luciliae, Trypanosoma mega, other protozoa and tissue cells in culture. The role of the approximate synchrony of nuclear and kinetoplastic cycles in maintenance of the kinetoplastic condition is discussed and the hypothesis is proposed that this synchrony results from the sharing by nucleus and kinetoplast of the same mechanism for the production of the deoxyribonucleotides used in replication of their respective DNA

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02350.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.Equations have been derived which relate the intracellular concentration of a metabolized sugar to its extracellular concentration and the kinetic constants for transport and phosphorylation. The equations show that the maximum intracellular, concentration of a metabolized sugar is a constant determined by the kinetic constants for transport and phosphorylation.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02351.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SYNOPSIS.The classicalTetrahymena pyriformisandT. voraxstrains have been classified in antigenic subgroups based on immobilization and agar double diffusion in the presence of specific antisera. The present study utilized disc electrophoresis of proteins and lactate dehydrogenase isozymes for comparison of 11 strains. In agreement with similarities reported for agar diffusion data, close electrophoretic relationships were observed between strains GL and H, and V2and W with aniline black staining. Altho LDH isozyme production was more variable and related to cultural growth phase, similarities were recognized between GL and H, and F and PR.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1970.tb02352.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY