Hyphal tip growth in Achlya: Enzyme activities in mycelium and medium

1979 ◽  
Vol 57 (20) ◽  
pp. 2145-2149 ◽  
Author(s):  
T. W. Hill ◽  
J. T. Mullins

Achlya ambisexualis Raper is a coenocytic, hyphal water mold which exhibits apical vegetative growth when cultured on a denned liquid medium. Upon transfer to a medium containing only glucose, growth is reduced considerably as measured by changes in fresh weight, incorporation of exogenous glucose into hyphal walls, and secretion of cellulase. Of the enzymes tested, only cellulase and alkaline phosphatase exhibit higher specific activities in growing mycelia than in nongrowing mycelia; the specific activity of UDPG transferase remains about the same. All enzyme activities found in mycelial extracts also were present in the culture filtrate. The only enzymes showing much higher activities in the filtrate than in the mycelium were ATPase and cellulase. Possible roles for cellulase during growth are discussed.

2013 ◽  
Vol 7 (2) ◽  
pp. 47-56
Author(s):  
Nihal E. Al- Taee ◽  
Sajida A. Abood ◽  
Mozahim K. Al-Mallah

The present study revealed that exposure of stem derived callus of Sesamum indicum L. that grown on initiation medium Murashige and Skoog (MS) supplemented with naphthalene acetic acid (NAA 1.0 mg L-1) + benzyl adenine BA 2.0 mg L-1 to 25, 30, 35, 40, 45 or 50◦ C as short term heat shock stHS 5,10 min. and long term heat shock ltHS 15, 20min. enhanced a desirable changes of callus growth. Moreover, the amounts of nucleic acids DNA, RNA, proteins and the specific activity of thymidylate synthase (TS), dihydrofolate reductase (DHFR) and serine hydroxy methyl transeferase (SHMT) enzymes were also increased. The heat shock treatment 40◦ C/15 min. gave the best effect in amount of both DNA and RNA that increased to 95 and 949 µg/g compared to control 58 and 550µg/g callus fresh weight respectively. Total protein was also increased to2.85 mg/g compared to control 1.47 mg/g. Maximum specific activities of TS, DHFR and SHMT enzymes were recorded 3.41, 0.97, 0.31µmol/min/mg protein respectively compared with control 1.70, 0.43, 0.13µmol/min/mg protein. Whereas, heat shock treatments 45 and 50◦ C of both tearms reduced each of callus fresh weight, DNA, RNA amount, and decreased the specific activities of the above enzymes.


1977 ◽  
Vol 85 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Jan Jelínek ◽  
Marta Jelínková

ABSTRACT The specific activities of lactate dehydrogenase (LDH) and its M-type (M-LDH), β-glucuronidase (β-GR), acid phosphatase (ACP) and alkaline phosphatase (AP) were determined. The specific activities of the enzymes (LDH, β-GR) in the myometrium were lower and their changes less pronounced than in the endometrium. We, therefore, determined the enzymes in the rat endometrium only in further experiments. All enzymes react sensitively to the changes induced in the endometrium by endogenous hormones in the course of a 4-day cycle: pro-oestrus (P) is characterized by rather low enzyme activities, oestrus (E) by a peak of LDH and M-LDH and a rise of AP. In metoestrus (M) there is a peak of β-GR, ACP and AP. Dioestrus (D) is characterized by a significant decrease in LDH and M-LDH and by elevated values of all the other enzymes. The values on the individual days of the 4–day cycle were compared with days 4–6 of pregnancy. The reason for this was that if the rats were not mated, they would, respectively, return to pro-oestrus instead of being 4 days pregnant, to oestrus instead of being 5 days pregnant, or to metoestrus instead of being 6 days pregnant. We found the following differences: on day 4 of pregnancy LDH and M-LDH were lower and ACP and AP higher than in P. On day 5 of pregnancy the LDH, M-LDH, β-GR and AP were lower than in E On day 6 of pregnancy the LDH, M-LDH, ACP and especially β-GR, were lower than in M.


1993 ◽  
Vol 69 (05) ◽  
pp. 430-435 ◽  
Author(s):  
Colin Longstaff ◽  
Man-Yu Wong ◽  
Patrick J Gaffney

SummaryAn international collaborative study has been carried out to investigate the reproducibility of hirudin assays in 13 laboratories using four recombinant hirudins and one natural, sulphated product. A simple assay procedure was proposed involving the titration of α-thrombin with inhibitor and measurement of residual activity using a chromogenic substrate. A standard α-thrombin preparation was supplied to ensure that this reagent was of uniform quality throughout the study. The method appeared to present no difficulties and laboratories reported similar potencies for the 5 hirudin samples, in line with expected values. This gave 200–222 Thrombin Inhibitory Units/ampoule (TIU/ampoule) of lyophilised hirudin, with geometric coefficient of variation (gcv) values ranging from 10.15–15.97%. This corresponds to specific activities of approximately 14,300–15,900 TIU/mg protein. This is close to the upper limit of previously reported values of specific activity. We conclude that the precision of this determination compared with the wider range of values in the literature (8,000–16,000 thrombin inhibitory units [TIU]/mg) results from the use of good quality standard α-thrombin by all laboratories. This study has important implications for hirudin standardisation.


2020 ◽  
Vol 16 (1) ◽  
pp. 58-63
Author(s):  
Amrutha Vijayakumar ◽  
Ajith Madhavan ◽  
Chinchu Bose ◽  
Pandurangan Nanjan ◽  
Sindhu S. Kokkal ◽  
...  

Background: Chitin is the main component of fungal, protozoan and helminth cell wall. They help to maintain the structural and functional characteristics of these organisms. The chitin wall is dynamic and is repaired, rearranged and synthesized as the cells develop. Active synthesis can be noticed during cytokinesis, laying of primary septum, maintenance of lateral cell wall integrity and hyphal tip growth. Chitin synthesis involves coordinated action of two enzymes namely, chitin synthase (that lays new cell wall) and chitinase (that removes the older ones). Since chitin synthase is conserved in different eukaryotic microorganisms that can be a ‘soft target’ for inhibition with small molecules. When chitin synthase is inhibited, it leads to the loss of viability of cells owing to the self- disruption of the cell wall by existing chitinase. Methods: In the described study, small molecules from plant sources were screened for their ability to interfere with hyphal tip growth, by employing Hyphal Tip Burst assay (HTB). Aspergillus niger was used as the model organism. The specific role of these small molecules in interfering with chitin synthesis was established with an in-vitro method. The enzyme required was isolated from Aspergillus niger and its activity was deduced through a novel method involving non-radioactively labelled substrate. The activity of the potential lead molecules were also checked against Candida albicans and Caenorhabditis elegans. The latter was adopted as a surrogate for the pathogenic helminths as it shares similarity with regard to cell wall structure and biochemistry. Moreover, it is widely studied and the methodologies are well established. Results: Out of the 11 compounds and extracts screened, 8 were found to be prospective. They were also found to be effective against Candida albicans and Caenorhabditis elegans. Conclusion: Purified Methyl Ethyl Ketone (MEK) Fraction1 (F1) of Coconut (Cocos nucifera) Shell Extract (COSE) was found to be more effective against Candida albicans with an IC50 value of 3.04 μg/mL and on L4 stage of Caenorhabditis elegans with an IC50 of 77.8 μg/mL.


2021 ◽  
Vol 9 (3) ◽  
pp. 522
Author(s):  
Lyudmila V. Gromova ◽  
Elena I. Ermolenko ◽  
Anastasiya L. Sepp ◽  
Yulia V. Dmitrieva ◽  
Anna S. Alekseeva ◽  
...  

In recent years, great interest has arisen in the use of autoprobiotics (indigenous bacteria isolated from the organism and introduced into the same organism after growing). This study aimed to evaluate the effects of indigenous bifidobacteria on intestinal microbiota and digestive enzymes in a rat model of antibiotic-associated dysbiosis. Our results showed that indigenous bifidobacteria (the Bf group) accelerate the disappearance of dyspeptic symptoms in rats and prevent an increase in chyme mass in the upper intestine compared to the group without autoprobiotics (the C1 group), but significantly increase the mass of chyme in the colon compared to the C1 group and the control group (healthy animals). In the Bf group in the gut microbiota, the content of opportunistic bacteria (Proteus spp., enteropathogenic Escherichia coli) decreased, and the content of some beneficial bacteria (Bifidobacterium spp., Dorea spp., Blautia spp., the genus Ruminococcus, Prevotella, Oscillospira) changed compared to the control group. Unlike the C1 group, in the Bf group there was no decrease in the specific activities of maltase and alkaline phosphatase in the mucosa of the upper intestine, but the specific activity of maltase was decreased in the colon chyme compared to the control and C1 groups. In the Bf group, the specific activity of aminopeptidase N was reduced in the duodenum mucosa and the colon chyme compared to the control group. We concluded that indigenous bifidobacteria can protect the microbiota and intestinal digestive enzymes in the intestine from disorders caused by dysbiosis; however, there may be impaired motor function of the colon.


Genetics ◽  
1982 ◽  
Vol 100 (1) ◽  
pp. 79-87
Author(s):  
Daniel W Nebert ◽  
Nancy M Jensen ◽  
Hisashi Shinozuka ◽  
Heinz W Kunz ◽  
Thomas J Gill

ABSTRACT Forty-four inbred and four randombred rat strains and 20 inbred mouse strains were examined for their Ah phenotype by determining the induction of liver microsomal aryl hydrocarbon (benzo[a]pyrene) hydroxylase activity (EC 1.14.14.1) by intraperitoneal treatment with either β-naphthoflavone or 3-methylcholanthrene. All 48 rat strains were found to be Ah-responsive. The maximally induced hydroxylase specific activities of the ALB/Pit, MNR/Pit, MR/Pit, SHR/Pit, and Sprague-Dawley strains were of the same order of magnitude as the basal hydroxylase specific activities of the ACI/Pit, F344/Pit, OKA/Pit, and MNR/N strains. Six of the 20 mouse strains were Ah-nonresponsive (i.e. lacking the normal induction response and presumably lacking detectable amounts of the Ah receptor). The basal hydroxylase specific activities of the BDL/N, NFS/N, STAR/N, and ST/JN mouse strains were more than twice as high as the maximally induced hydroxylase specific activity of the CBA/HT strain.——To date, 24 Ah-nonresponsive mouse strains have been identified, out of a total of 68 known to have been characterized. The reasons for not finding a single Ah-nonresponsive inbred rat strain—as compared with about one Ah-nonresponsive inbred mouse strain found for every three examined—remain unknown.


1982 ◽  
Vol 208 (3) ◽  
pp. 611-618 ◽  
Author(s):  
M R Grigor ◽  
A Geursen ◽  
M J Sneyd ◽  
S M Warren

1. The rate of mammary-gland lipogenesis measured in vivo from 3H2O was suppressed after decreasing the milk demand by decreasing the number of pups from ten to two or three, as well as by giving diets containing lipid [Grigor & Warren (1980) Biochem. J. 188, 61-65]. 2. The specific activities of the lipogenic enzymes fatty acid synthase, glucose 6-phosphate dehydrogenase and ‘malic’ enzyme increased between 6- and 10-fold in the mammary gland and between 2- and 3-fold in the livers during the first 10 days of lactation. The increases in specific activity coupled with the doubling of liver mass which occurred during pregnancy and lactation resulted in considerable differences in total liver activities when compared with virgin animals. 3. Although consumption of a diet containing 20% peanut oil suppressed the activities of the three lipogenic enzymes in the livers, only the ‘malic’ enzyme was affected in the mammary glands. 4. In contrast, decreased milk demand did not affect the specific activities of any of the liver enzymes, whereas it resulted in suppression of all three lipogenic enzymes of the mammary glands. There was no effect on either the cytoplasmic malate dehydrogenase or the lactate dehydrogenase of the mammary gland. 5. In all the experiments performed, the activity of the fatty acid synthase correlated with the amount of material precipitated by the rabbit antibody raised against rat fatty acid synthase.


2007 ◽  
Vol 75 (3) ◽  
Author(s):  
K. E. P. Sugden ◽  
M. R. Evans ◽  
W. C. K. Poon ◽  
N. D. Read

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