scholarly journals Extraction, characterization, and biological toxicity of β-glucans from Saccharomyces cerevisiae isolated from ragi

2020 ◽  
Vol 2 (2) ◽  
pp. 35-43
Author(s):  
Indriati Ramadhani ◽  
Diva Larissa ◽  
Yeni Yuliani ◽  
Mellova Amir ◽  
Kusmiati Kusmiati

β-glucan is a homopolysaccharide with biological activities that are beneficial to health as an immunostimulant, anti-inflammatory, anti-diabetic, anti-cholesterol, and many more. β-glucan extraction results from yeast require characterization related to this bioactive quality, such as β-glucan weight, monomer analysis, functional groups, and cytotoxicity assay. Four Saccharomyces cerevisiae isolates were isolated from three local ragi samples, namely the SC-1, SC-2, SC-3, and SAF from instant ragi. This study aimed to obtain the best candidate of S. cerevisiae isolates to produce high β-glucan levels and low protein levels and to test the potential for cytotoxicity. The four isolates were rejuvenated on potato dextrose agar (PDA), then inoculated into the liquid glucose yeast peptone (GYP) fermentation medium for six days. Saccharomyces cerevisiae cells were extracted by neutralizing acid-base, dried and weighed as a crude β-glucan (mg per 300 mL). The highest yield was SC-2 (818 mg), followed by SC-3 (726 mg), SAF (597 mg), and SC-1 (433 mg). The presence of –OH (alcohol), -C-C-C- (alkane), and –R-O-R- (ether) groups were showed using FTIR characterization. Glucose equivalent β-glucan levels and protein levels were determined using a UV-Vis spectrophotometer. The results showed that β-glucan SC-1 gave the best results with glucose equivalent β-glucan levels of 4,865% and protein levels of 3,804%. The crude β-glucan toxicity test using the brine shrimp lethality test (BSLT) method shows that the β-glucan of the SAF strain has LC50 cytotoxicity of 114.8 ppm followed by β-glucan cytotoxicity from local ragi LC50 was SC-2 (323.5 ppm), SC-1 (331.1 ppm), and SC-3 (354.8 ppm). Therefore, based on the results, SC-1 isolate obtained the highest β-glucan crude and the lowest protein content was SC-2. The β-glucan of SAF extract had the highest toxicity properties based on the IC50 value.

Author(s):  
Deedarul Hyder Sani ◽  
Ali Newaz Munna ◽  
Mohammad Salim ◽  
Md. Jahangir Alam ◽  
Md. Jahangir Alam

Background: Diabetes mellitus is the most occurring non-communicable disease resulting in a high blood glucose level. There has been an immense interest in the development of alternative medicines for diabetes treatment, specifically screening functional foods for phytochemicals with the capability of delaying or preventing glucose absorption through digestive enzymes (e.g. α-amylase) inhibition. So, the development of α-amylase inhibitors derived from natural food products is an alternative way to prevent diabetes mellitus Objective: In this study, organic solvent extracts of the Arachis hypogaea (Peanut) and Cinnamomum tamala (Indian bay leaf /Tejpata) were used to investigate their potential α-amylase inhibition and cytotoxic activities through α-amylase inhibition assay and brine shrimp lethality bioassay respectively Method: The α-amylase inhibition assay was performed using the 3,5-dinitrosalicylic acid method for different concentrations of plant extracts. The optical density (OD) of the solutions were measured to determine the inhibition activity at 540 nm using a spectrophotometer. The cytotoxicity of the plant extracts was measured using brine shrimp (Artemia salina) lethality bioassay Results: Among the different organic solvent extracts, peanut seed ethanol extract showed the highest α-amylase inhibition activity (67.68±8.67%) at 1.25 μg/mL concentration with an IC50 value of 0.61 μg/mL which is very close to standard α-amylase inhibitor Acarbose (72.34±4.23%) with an IC50 value of 0.32 μg/mL while acetone extract of Indian bay leaf exhibited the lowest inhibition activity (47.75±1.63%) with an IC50 value of 1.42 μg/mL at the same concentration. Besides, the maximum cytotoxic activity was found in acetone extract of peanut shell with an LC50 value of 57.87 μg/mL whereas ethanol extract of peanut seed showed the lowest cytotoxicity with an LC50 value of 413.90 μg/mL Conclusion: The result of the present work clearly indicates the potentiality of peanut seed ethanol extract to be used in the management of hyperglycemia as it significantly inhibits α-amylase activity while showing less cytotoxic activities


Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1205-1219 ◽  
Author(s):  
Jeffrey S Smith ◽  
Carrie Baker Brachmann ◽  
Lorraine Pillus ◽  
Jef D Boeke

Abstract Transcriptional silencing in Saccharomyces cerevisiae occurs at the silent mating-type loci HML and HMR, at telomeres, and at the ribosomal DNA (rDNA) locus RDN1. Silencing in the rDNA occurs by a novel mechanism that depends on a single Silent Information Regulator (SIR) gene, SIR2. SIR4, essential for other silenced loci, paradoxically inhibits rDNA silencing. In this study, we elucidate a regulatory mechanism for rDNA silencing based on the finding that rDNA silencing strength directly correlates with cellular Sir2 protein levels. The endogenous level of Sir2p was shown to be limiting for rDNA silencing. Furthermore, small changes in Sir2p levels altered rDNA silencing strength. In rDNA silencing phenotypes, sir2 mutations were shown to be epistatic to sir4 mutations, indicating that SIR4 inhibition of rDNA silencing is mediated through SIR2. Furthermore, rDNA silencing is insensitive to SIR3 overexpression, but is severely reduced by overexpression of full-length Sir4p or a fragment of Sir4p that interacts with Sir2p. This negative effect of SIR4 overexpression was overridden by co-overexpression of SIR2, suggesting that SIR4 directly inhibits the rDNA silencing function of SIR2. Finally, genetic manipulations of SIR4 previously shown to promote extended life span also resulted in enhanced rDNA silencing. We propose a simple model in which telomeres act as regulators of rDNA silencing by competing for limiting amounts of Sir2 protein.


Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 761-776 ◽  
Author(s):  
Lori A Rinckel ◽  
David J Garfinkel

Abstract In Saccharomyces cerevisiae, the target site specificity of the retrotransposon Ty1 appears to involve the Ty integration complex recognizing chromatin structures. To determine whether changes in chromatin structure affect Ty1 and Ty2 target site preference, we analyzed Ty transposition at the CAN1 locus in mutants containing altered levels of histone proteins. A Δhta1-htb1 mutant with decreased levels of H2A and H2B histone proteins showed a pattern of Ty1 and Ty2 insertions at CAN1 that was significantly different from that of both the wild-type and a Δhta2-htb2 mutant, which does not have altered histone protein levels. Altered levels of H2A and H2B proteins disrupted a dramatic orientation bias in the CAN1 promoter region. In the wild-type strains, few Ty1 and Ty2 insertions in the promoter region were oriented opposite to the direction of CAN1 transcription. In the Δhta1-htb1 background, however, numerous Ty1 and Ty2 insertions were in the opposite orientation clustered within the TATA region. This altered insertion pattern does not appear to be due to a bias caused by selecting canavanine resistant isolates in the different HTA1-HTB1 backgrounds. Our results suggest that reduced levels of histone proteins alter Ty target site preference and disrupt an asymmetric Ty insertion pattern.


1973 ◽  
Vol 24 (4) ◽  
pp. 613 ◽  
Author(s):  
GJ Faichney ◽  
HL Davies

Five groups of Friesian bull calves were given concentrate diets containing 70 % barley in which low (12 %), medium (15 %), and high (19%) protein levels were obtained by varying the amount of peanut meal included. The effects of protein level and of formaldehyde treatment of the complete diet at the low and medium protein levels were studied in terms of liveweight gain, voluntary food consumption, digestibility of the diet, ammonia nitrogen in rumen fluid, and urea and a-amino nitrogen in blood plasma. Observations were begun when the calves reached 70 kg liveweight and continued until they reached 130 kg liveweight. The calves given the low protein diets grew more slowly than those given the higher protein diets. The calves given the high protein diet grew no better than those given the medium protein diets. Formaldehyde treatment was associated with an increase in the rate of liveweight gain of 9% (P = 0.11) at the low protein level but had practically no effect at the medium protein level. The treatment did not adversely affect voluntary food consumption but was associated with decreases in the digestibility of nitrogen and in rumen ammonia levels and small increases in plasma urea levels.


2000 ◽  
Vol 80 (4) ◽  
pp. 633-642 ◽  
Author(s):  
Palle V. Rasmussen ◽  
Christian F. Børsting

The effect of different and shifting dietary protein levels on hair growth and the resulting pelt quality in mink was studied. Two groups of pastel female mink were fed either 59% (high protein, HP) or 40% (low protein, LP) of metabolisable energy (ME) from protein during pregnancy and lactation. Shortly after weaning, kits from females fed the LP diet were put on a new LP diet (21% protein of ME). Kits from females fed HP were randomly distributed to four experimental groups fed a new HP diet (34% protein of ME) and three of these groups were shifted to diets with 21% protein at different times during June until September. Skin biopsies were taken at 4, 6, 23 and, 29 wk of age. Histological techniques and computer-assisted light microscopy were used to determine the ratio of activity (ROA) of underfur and guard hairs, respectively, defined as the number of growing hairs as a percentage of the total number of hairs. The hair fibre length and thickness were determined by morphometric methods and correlated with fur properties of dried pelts judged by sensory methods. It was documented that 40% of ME from protein during pregnancy and lactation was sufficient for mink kits to express their genetic capacity to produce hair follicles. In males, a reduced protein level from the age of 15 wk or 22 wk until pelting disturbed moulting, indicated by a low ROA of underfur hairs at 23 wk, and consequently reduced the growth and development of the winter coat. A constantly low protein level from conception until the age of 29 wk did not disturb moulting, but led to a reduction of primeness and especially of the underfur length and fibre thickness of the winter coat. A low protein level from the age of 9 wk only reduced the thickness of the underfur fibres. Hair growth, final fur volume, and general quality of the winter coat of males were influenced negatively and to the same degree in all groups fed the LP diet in part of the growth period. The number of underfur hairs per area (hair density) of the winter coat was not influenced by the dietary treatment meaning that the protein content of 21% of ME in the LP diet was high enough for the mink to express its genetic capacity to develop hair follicles. However, this low protein content led to a reduction of hair fibre length and hair fibre thickness of the underfur. Overall, this study demonstrated that hair growth and hair properties in pelts are very dependent on the dietary protein supply in the period from 22 wk of age until pelting, irrespective of the supply in the preceding periods. Key words: Fur properties, hair fibres, nutrition, pelage, protein requirement


1970 ◽  
Vol 3 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Afia Ferdous ◽  
Mohammad Zafar Imam ◽  
Tajnin Ahmed

In the present investigation the n-hexane, carbon tetrachloride and choloroform soluble fractions of crude methanolic extract of Samanea saman bark were tested for antioxidant, antimicrobial and cytotoxic potential. Antioxidant activity of the extracts was evaluated by DPPH radical scavenging assay and total antioxidant activity test. Antimicrobial activity was tested using disc diffusion method against thirteen bacteria and three fungi and cytotoxicity was tested by brine shrimp lethality bioassay. Chloroform and hexane soluble fraction showed IC50 value of 12μg/ml and 14μg/ml respectively in scavenging DPPH radical while the reference Butylated hydroxytoluene showed an IC50 value of 10μg/ml. The carbon tetrachloride fraction showed the highest total antioxidant capacity. The carbon tetrachloride fraction was also found to possess mild to moderate microbial growth inhibitory capacity. In the brine shrimp lethality bioassay, the n-hexane, carbon tetrachloride, chloroform soluble fractions showed LC50 value of 14.94μg/ml, 0.831μg/ml and 3.288μg/ml respectively. The results suggest good antioxidant and cytotoxic potential of chloroform and hexane soluble fractions and antimicrobial activity of carbon tetrachloride fraction of Samanea saman bark extract. Key Words: Samanea saman; Leguminoseae; Cytotoxicity; Antimicrobial; Antioxidant; Total antioxidant capacity. DOI: 10.3329/sjps.v3i1.6792S. J. Pharm. Sci. 3(1): 11-17


2018 ◽  
Vol 51 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Jia Zhu ◽  
Rui Zhang ◽  
Dongxiang Yang ◽  
Jibin Li ◽  
Xiaofei Yan ◽  
...  

Background/Aims: Doxorubicin (DOX) is a widely used chemotherapeutic agent for colorectal cancer (CRC). However, the acquirement of DOX resistance limits its clinical application for cancer therapy. Mounting evidence has suggested that aberrantly expressed lncRNAs contribute to drug resistance of various tumors. Our study aimed to explore the role and molecular mechanisms of lncRNA X-inactive specific transcript (XIST) in chemoresistance of CRC to DOX. Methods: The expressions of XIST, miR-124, serum and glucocorticoid-inducible kinase 1 (SGK1) mRNA in DOX-resistant CRC tissues and cells were detected by qRT-PCR or western blot analysis. DOX sensitivity was assessed by detecting IC50 value of DOX, the protein levels of P-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) and apoptosis. The interactions between XIST, miR-124 and SGK1 were confirmed by luciferase reporter assay, qRT-PCR and western blot. Xenograft tumor assay was used to verify the role of XIST in DOX resistance in CRC in vivo. Results: XIST expression was upregulated and miR-124 expression was downregulated in DOX-resistant CRC tissues and cells. Knockdown of XIST inhibited DOX resistance of CRC cells, as evidenced by the reduced IC50 value of DOX, decreased P-gp and GST-π levels and enhanced apoptosis in XIST-silenced DOX-resistant CRC cells. Additionally, XIST positively regulated SGK1 expression by interacting with miR-124 in DOX-resistant CRC cells. miR-124 suppression strikingly reversed XIST-knockdown-mediated repression on DOX resistance in DOX-resistant CRC cells. Moreover, SGK1-depletion-elicited decrease of DOX resistance was greatly restored by XIST overexpression or miR-124 inhibition in DOX-resistant CRC cells. Furthermore, XIST knockdown enhanced the anti-tumor effect of DOX in CRC in vivo. Conclusion: XIST exerted regulatory function in resistance of DOX possibly through miR-124/SGK1 axis, shedding new light on developing promising therapeutic strategy to overcome chemoresistance in CRC patients.


1982 ◽  
Vol 62 (4) ◽  
pp. 1193-1197 ◽  
Author(s):  
P. A. THACKER ◽  
J. P. BOWLAND ◽  
L. P. MILLIGAN ◽  
E. WELTZIEN

The kinetics of urea recycling were determined in six female crossbred pigs utilizing a radioisotope dilution technique. The experimental animals were fed three times daily 500 g of a corn-soybean meal diet formulated to contain 8.4, 15.8 or 24.7% crude protein. Nitrogen digestibility, urinary nitrogen excretion, total nitrogen excretion and retained nitrogen were highest on the 24.7% protein diet and decreased with decreasing dietary protein. Urea pool size, entry rate and excretion rate were also highest on the 24.7% protein diet and decreased with decreasing protein intake. Expressed as a percentage of the total entry rate, a significantly higher percentage of urea was recycled in pigs fed the low protein diets compared with those fed a higher protein diet. Key words: Pig, urea, recycling, kinetics, protein


2017 ◽  
Vol 4 (03) ◽  
pp. e108-e113 ◽  
Author(s):  
Augustine Ahmadu ◽  
Abdulkarim Agunu ◽  
Thi-Ngoc-Dung Nguyen ◽  
Blandine Baratte ◽  
Béatrice Foll-Josselin ◽  
...  

Abstract Acacia nilotica (L.) Delile belongs to the genus Acacia, which includes about 1400 species in subtropical and tropical Africa including Nigeria, Senegal, Egypt, and Mozambique as well as Asia from India to Burma. This plant is traditionally used to treat several pathologies such as mouth, ear, and bone cancer. Moreover, it possesses many other biological activities (antidiarrheal, anti-inflammatory, antimicrobial, and antifungal). We report here the extraction, purification, and identification of two known compounds [ethylgallate and (+)-catechin] from the bark of the tree that were further tested for their inhibitory activities against a panel of disease-related protein kinases. Both compounds were active, and (+)-catechin showed the best activity by inhibiting nine out of fourteen protein kinases with an IC50 value in the µg/mL range. This compound gave the highest activity against CLK1 with an IC50 of 2.1 µg/mL. The ethyl acetate extract and its components, such as catechins and other polyphenols, which also had protein kinase inhibitory activity, can be exploited in the research for anticancer agents.


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