Relationship between iron-limited growth and energy limitation during phased cultivation of Candida utilis

1978 ◽  
Vol 24 (4) ◽  
pp. 440-447 ◽  
Author(s):  
K. C. Thomas ◽  
P. S. S. Dawson

The yeast Candida utilis was continuously synchronized by the phasing technique (6 h doubling time) with either iron or nitrogen as the limiting nutrient. Iron limitation resulted in decreased molar growth yields with respect to the carbon substrates and ammonia and in increased specific rates of oxygen uptake. Relatively low energy-charge values were maintained by the iron-limited culture. All these taken together seemed to indicate that the growth of the yeast under iron limitation was also limited by metabolically available energy.Considerable amounts of ethyl acetate were produced by the yeast under phased cultivation when the growth was limited by iron but not by nitrogen. In vitro studies using cell-free extracts showed that the substrates for ethyl acetate synthesis were acetyl coenzyme A (acetyl CoA) and ethanol. Under iron-limited growth acetyl CoA seemed to be diverted to ethyl acetate formation rather than being oxidized through the tricarboxylic acid (TCA) cycle. The possibility of energy limitation under iron-limited growth being brought about by the reduced capacity of the yeast to oxidize acetyl CoA through the TCA cycle is considered.

1977 ◽  
Vol 23 (12) ◽  
pp. 1689-1694 ◽  
Author(s):  
P. S. S. Dawson ◽  
L. P. Steinhauer

The release of 14CO2 from specifically labelled glucose ([G-1-14C], [G-2-14C], [G-3,4-14C], and [G-6-14C]) by phased cells of C. utilis was examined at intervals during 6-h cycles under conditions of N-, P-, and C-limited growth.On the basis that the release of 14CO2 from [G-1-C14] could serve as a measure of hexose monophosphate pathway (HMP) activity, of 14CO2 from [G-3,4-14C] as a measure of Embden–Meyerhof–Parnas (EMP) activity, and 14CO2 from [G-6-14C] as indicative of tricarboxylic acid (TCA) cycle activity, it was concluded that a relatively uniform operation of EMP occurred throughout the cycle in N-, P-, and C-limited cells, and of HMP and TCA in C-limited cells, but considerable variations took place in HMP and TCA cycle activities in N- and P-limited cells. The patterns of 14CO2 released from [G-2-14C] were more closely related to those observed from[G-1-14C] and [G-3,4-14C] than from [G-6-14C].Changes in the rate of 14CO2 evolution during the cycle were sometimes abrupt and likely coincided with 'critical points' of metabolic activity in the cycle.


1968 ◽  
Vol 14 (10) ◽  
pp. 1127-1131 ◽  
Author(s):  
J. Müller ◽  
P. S. S. Dawson

The oxygen uptake of Candida utilis growing in phased culture at doubling times of 4, 6, 8, and 12 hours was measured under conditions of nitrogen and energy source limitation. No abrupt doubling of oxygen uptake was observed at any stage of the cell cycle. The pattern of oxygen uptake was closely related to the assimilation of the growth-limiting nutrient. In nitrogen-limited growth, the specific oxygen uptake (Qo2) was found to decrease as the doubling time increased, but, in glucose-limited growth, no change was observed.


1971 ◽  
Vol 124 (1) ◽  
pp. 123-134 ◽  
Author(s):  
P. A Light ◽  
P. B. Garland

1. Mitochondria prepared from Torulopsis utilis grown in a chemostat with iron-limited growth were found to lack energy conservation but not electron flow in that segment of the respiratory chain leading from intramitochondrial NADH to the cytochromes [i.e. the site 1 segment (Lehninger, 1964)]. 2. Site 1 energy conservation was present in mitochondria prepared from cells grown under conditions of limitation by glycerol, ammonium and magnesium. Phosphate-limited growth resulted in mitochondrial preparations without respiratory control. 3. Mitochondria from cells grown under conditions of iron limitation were insensitive to the respiratory inhibitor piericidin A, whereas sensitivity was present in mitochondria prepared from glycerol-, ammonium-, magnesium- or phosphate-limited cells. 4. These observations are considered to provide indirect evidence for a role of non-haem iron in the mechanism of energy conservation and also piericidin A sensitivity in T. utilis mitochondria. 5. A readily constructed and inexpensive pH-measuring and -controlling circuit is described for use with continuous-culture apparatus.


Author(s):  
Shubhaisi Das ◽  
Sunanda Burman ◽  
Goutam Chandra

Background: The only remedy for up surging problem of antibiotic resistance is the discovery of antibacterial agents of natural origin. Objective: The present study was aimed at finding antibacterial potential of crude and solvent extracts of mature leaves of Plumeria pudica. Methods: Antibacterial activity of three different solvent extracts were evaluated in four human and four fish pathogenic bacteria by measuring the zone of inhibition and determining Minimum Inhibitory Concentration and Minimum Bactericidal Concentration values. Standard antibiotics were used as positive control. Preliminary phytochemical screening of most effective extract i.e., ethyl acetate extract, Fourier Transform Infra Red analysis and GC-MS analysis of the Thin Layer Chromatographic (TLC) fraction of ethyl acetate extract were done meticulously. All experiments were done thrice and analyzed statistically. Results: Crude leaf extracts and solvent extracts caused good inhibition of bacterial growth in all selected bacteria. Ethyl acetate extract showed highest inhibition zones in all tested strains with maximum inhibition (19.50±0.29 mm) in Escherichia coli (MTCC 739). MBC/MIC of the extracts indicated that all three solvent extracts were bactericidal. Preliminary phytochemical tests revealed the presence of tannins, steroids and alkaloids and FT-IR analysis revealed presence of many functional groups namely alcoholic, amide, amine salt and aldehyde groups. From the GC-MS analysis of TLC fraction of ethyl acetate extract five different bioactive compounds e.g., 2,4-ditert –butylphenyl 5-hydroxypentanoate, Oxalic acid; allyl nonyl ester, 7,9-Ditert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione, Dibutyl phthalate and 2,3,5,8-tetramethyl-decane were identified. Conclusion: Leaf extracts of P. pudica contain bioactive compounds that can be used as broad spectrum bactericidal agent.


2020 ◽  
Vol 14 (4) ◽  
pp. 295-311
Author(s):  
Ada Gabriel ◽  
Mamman Mohammed ◽  
Mohammed G. Magaji ◽  
Yusuf P. Ofemile ◽  
Ameh P. Matthew ◽  
...  

Background: Snakebite envenomation is a global priority ranked top among other neglected tropical diseases. There is a folkloric claim that Uvaria chamae is beneficial for the management of snakebite and wounds in African ethnobotanical surveys. Besides, there are many registered patents asserting the health benefits of U. chamae. Objective: This study aimed to investigate U. chamae’s potentials and identify candidates for the development of tools for the treatment and management of N. nigricollis envenomation. Methods: Freshly collected U. chamae leaves were air-dried, powdered, and extracted in methanol. The median lethal dose of the extract was determined and further fractionated with n-hexane, n-butanol and ethyl acetate. Each fraction was tested for neutralizing effect against venom-induced haemolytic, fibrinolytic, hemorrhagic, and cytotoxic activities. Results: U. chamae fractions significantly (p<0.05) neutralized the haemolytic activity of N. nigricollis venom in n-butanol; 31.40%, n-hexane; 33%, aqueous residue; 39.60% and ethyl acetate; 40.70% at the concentration of 100mg/ml of each fraction against 10mg/ml of the snake venom when compared to the positive control. The fibrinolytic activity of N. nigricollis venom was significantly (p<0.05) neutralized in n-hexane at 73.88%, n-butanol; 72.22% and aqueous residue; 72.22% by the fractions of U. chamae. In addition, haemorrhagic activity of N. nigricollis venom was significantly (p<0.05) neutralized by U. chamae fractions at the concentrations of 100mg/ml, 200mg/ml and 400mg/ml except for n-butanol and aqueous residues at 400 mg/ml. Conclusion: U. chamae leaves fractions possess a high level of protection against N. nigricollis venoms-induced lethality and thus validate the pharmacological rationale for its usage in the management of N. nigricollis envenomation.


2020 ◽  
Vol 6 (2) ◽  
pp. 155-169
Author(s):  
Neeraj Panihar ◽  
Neeru Vasudeva ◽  
Sunil Sharma ◽  
Babu Lal Jangir

Background: Fagopyrum esculentum Moench. is a herb consumed as food and has medicinal value. It is a rich source of bioactive nutrients which cure and prevent many ailments. Traditionally, it is used to treat hypertension, diabetes, constipation, cancer etc. Methods and Objective: Present work illustrates morphological, microscopic and physicochemical parameters of Fagopyrum esculentum seeds as per WHO guidelines, in vitro antioxidant activity; assessed by DPPH scavenging method, hydrogen peroxide scavenging assay and β-carotene linoleic acid bleaching method and study of lipid lowering potential of the ethyl acetate and ethanol extract of seeds on normal diet fed Wistar rats. Results: Morphological studies delineated the triangular shape, dark brown colour, 8 mm length and 6 mm width of the seed. The microscopic examination of the transverse section of seed depicted features like testa or pericarp (seed coat), the endosperm, embryo and sclerenchyma cells. Study of physiochemical parameters exhibited 0.3±0.02% of foreign matter and 1.44±0.51% crude fibre content. Total ash, acid insoluble ash and water soluble ash value were 6.7±1.7%, 1.9±0.23% and 3.9± 0.31% respectively. Alcohol soluble and water soluble extractive value came out to be 65.02± 3.21 mg/g and 12.7±1.24 mg/g respectively. Foaming index was less than 100, swelling index was found to be 0.5±0.01 ml/g. Loss on drying was 4.02±1.27%. Phytochemical screening of ethyl acetate and ethanol extract revealed the presence of alkaloids, carbohydrates, phenolic compounds, phytosterols and flavonoids. Trace amount of heavy metals (arsenic, cadmium, lead, mercury) were determined by atomic absorption spectrophotometer. Pesticide residue analysis confirmed the presence of nontoxic pesticides like dimethipin, hymexazol, phenothrin-2, methoprene, triadimenol, prohydrojasmon- 1, jasmolin ii, triademinol, jasmolin i, prohydrojasmone i, cyromazine in both the extracts by gc-ms spectrometer. The ethyl acetate and ethanol extract has shown significant in-vitro antioxidant activities demonstrated by the DPPH method (IC50 = 94.37±2.51 and 216.04±4.39 μg/ml respectively), hydrogen peroxide scavenging assay (IC50 = 83.72±3.72 and 193.47±5.05 µg/ml respectively) and β-carotene bleaching method (IC50 = 100.67±4.01 and 205.39±2.89 µg/ml respectively). Lipid lowering study performed on Wistar rats demonstrated a significant (p<0.001) decrease in serum Total Cholesterol (TC), Triglyceride (TG) and increase in High Density Lipoprotein (HDL) level as compared to normal group. Both the extracts have shown a non significant difference in the level of TG as compared to standard drug atorvastatin, depicting that the efficacy of extracts is at par with that of standard drug atorvastatin. Conclusion: Pharmacognostical study of the plant can be a very good tool for identification as well as authentication of a herb. Moreover, these parameters may be helpful in the development of monograph of the plant. Pharmacological activity confirmed Fagopyrum esculentum Moench. seed to be a good antioxidant and have lipid lowering potential.


Foods ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 144
Author(s):  
Immacolata Faraone ◽  
Daniela Russo ◽  
Lucia Chiummiento ◽  
Eloy Fernandez ◽  
Alka Choudhary ◽  
...  

The genus Minthostachys belonging to the Lamiaceae family, and is an important South American mint genus used commonly in folk medicine as an aroma in cooking. The phytochemical-rich samples of the aerial parts of Minthostachys diffusa Epling. were tested for pharmacological and health-promoting bioactivities using in vitro chemical and enzymatic assays. A range of radical scavenging activities of the samples against biological radicals such as nitric oxide and superoxide anion and against synthetic 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, the ferric reducing antioxidant power and the lipid peroxidation inhibition were determined and ranked using the ‘relative antioxidant capacity index’ (RACI). The ethyl acetate fraction showed the highest RACI of +1.12. Analysis of the various fractions’ inhibitory ability against enzymes involved in diabetes (α-amylase and α-glucosidase), and against enzymes associated with Parkinson’s or Alzheimer’s diseases (acetylcholinesterase and butyrylcholinesterase) also suggested that the ethyl acetate fraction was the most active. Liquid chromatography–tandem mass spectrometry analysis of the ethyl acetate fraction showed more than 30 polyphenolic compounds, including triterpenes. The inhibitory cholinesterase effects of the triterpenes identified from M. diffusa were further analysed by in silico docking of these compounds into 3D-structures of acetylcholinesterase and butyrylcholinesterase. This is the first study on pharmacological activities and phytochemical profiling of the aerial parts of M. diffusa, showing that this plant, normally used as food in South America, is also rich in health-promoting phytochemicals.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 315
Author(s):  
Zhenxing Wang ◽  
Zongcai Tu ◽  
Xing Xie ◽  
Hao Cui ◽  
Kin Weng Kong ◽  
...  

This study aims to evaluate the bioactive components, in vitro bioactivities, and in vivo hypoglycemic effect of P. frutescens leaf, which is a traditional medicine-food homology plant. P. frutescens methanol crude extract and its fractions (petroleum ether, chloroform, ethyl acetate, n-butanol fractions, and aqueous phase residue) were prepared by ultrasound-enzyme assisted extraction and liquid–liquid extraction. Among the samples, the ethyl acetate fraction possessed the high total phenolic (440.48 μg GAE/mg DE) and flavonoid content (455.22 μg RE/mg DE), the best antioxidant activity (the DPPH radical, ABTS radical, and superoxide anion scavenging activity, and ferric reducing antioxidant power were 1.71, 1.14, 2.40, 1.29, and 2.4 times higher than that of control Vc, respectively), the most powerful α-glucosidase inhibitory ability with the IC50 value of 190.03 μg/mL which was 2.2-folds higher than control acarbose, the strongest proliferative inhibitory ability against MCF-7 and HepG2 cell with the IC50 values of 37.92 and 13.43 μg/mL, which were considerable with control cisplatin, as well as certain inhibition abilities on acetylcholinesterase and tyrosinase. HPLC analysis showed that the luteolin, rosmarinic acid, rutin, and catechin were the dominant components of the ethyl acetate fraction. Animal experiments further demonstrated that the ethyl acetate fraction could significantly decrease the serum glucose level, food, and water intake of streptozotocin-induced diabetic SD rats, increase the body weight, modulate their serum levels of TC, TG, HDL-C, and LDL-C, improve the histopathology and glycogen accumulation in liver and intestinal tissue. Taken together, P. frutescens leaf exhibits excellent hypoglycemic activity in vitro and in vivo, and could be exploited as a source of natural antidiabetic agent.


2021 ◽  
Vol 11 (11) ◽  
pp. 5300
Author(s):  
Jozef Hudec ◽  
Jan Mojzis ◽  
Marta Habanova ◽  
Jorge A. Saraiva ◽  
Pavel Hradil ◽  
...  

Sarcopoterium spinosum (L.) is a medicinal plant traditionally used for the treatment of various diseases including cancer in the Near- and Middle East. The fractions and constituents of the ethanol extract of S. spinosum were screened for in vitro cytotoxic activities on Jurkat (acute T-lymphoblastic leukemia), HeLa (cervical adenocarcinoma), MCF-7 (mammary gland adenocarcinoma), Caco-2 (human colorectal adenocarcinoma), and MDA-MB-231 (mammary gland adenocarcinoma) cell lines using the MTT (3-(dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The ethanol extract was subsequently re-extracted with ethyl acetate and in its sub-fraction obtained by column chromatography three compounds (stachydrine, benzalkonium chloride and rutine) were the first time identified by nuclear magnetic resonance (NMR) analyses. The most active subfraction showed cytotoxic activity against HeLa, MCF-7, and Caco-2 cell lines. The three compounds mentioned, as standards of high-performance liquid chromatography (HPLC) quality, were studied individually and in combination. Cytotoxic activity observed might be due to the presence of benzalkonium chloride and rutin. Benzalkonium chloride showed the strongest growth suppression effect against HeLa cells (IC50 8.10−7 M) and MCF-7 cells (IC50 5.10−6 M). The mixture of stachydrine and benzalkonium chloride allowed a synergistic cytotoxic effect against all tested cancer and normal cells to be obtained. Anti-cancer activity of the plant extract of S. spinosum remains under-investigated, so this research describes how the three major compounds identified in the ethyl acetate extract can exert a significant dose dependent in vitro cytotoxicity.


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