ISOLATION AND CHARACTERIZATION OF RIBONUCLEIC ACID FROM RAT LENS

1962 ◽  
Vol 40 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Anima Devi

RNA from rat ocular lens has been isolated by a method based on Kirby's original procedure (7), but greatly modified so as to avoid any degradation of RNA by RNase during the process of its extraction from lenses. The absorption at 260 mμ of a 1.0% solution of this purified material in a 1-cm cell is 1.95. Its N/P ratio is 1.58. It has 20 to 25% activity of that of yeast-soluble RNA in accepting activated amino acids. When this RNA (like all other RNA's) is heated and cooled the polynucleotide chain can again form loops, thus suggesting a randomly coiled structure for this RNA. On the other hand, DNA preparations from calf thymus, rat liver, and E. coli showed irreversible changes when heated and cooled.

1962 ◽  
Vol 40 (1) ◽  
pp. 41-47
Author(s):  
Anima Devi

RNA from rat ocular lens has been isolated by a method based on Kirby's original procedure (7), but greatly modified so as to avoid any degradation of RNA by RNase during the process of its extraction from lenses. The absorption at 260 mμ of a 1.0% solution of this purified material in a 1-cm cell is 1.95. Its N/P ratio is 1.58. It has 20 to 25% activity of that of yeast-soluble RNA in accepting activated amino acids. When this RNA (like all other RNA's) is heated and cooled the polynucleotide chain can again form loops, thus suggesting a randomly coiled structure for this RNA. On the other hand, DNA preparations from calf thymus, rat liver, and E. coli showed irreversible changes when heated and cooled.


1970 ◽  
Vol 18 ◽  
pp. 99-103 ◽  
Author(s):  
S Biswas ◽  
MAK Parvez ◽  
M Shafiquzzaman ◽  
S Nahar ◽  
MN Rahman

Context: Escherichia coli is shed in the feces of warm blooded animals and humans and thus potential for public health. Detection and characterization of E. coli in the ready-to-eat (RTE) foods concerns due to their presence indicates fecal contamination of the food.   Objective: To identify, characterize and RFLP pattern analysis of E. coli isolated from RTE foods vended in Islamic University campus, Kushtia.   Materials and Methods: Fifty samples from four types of consumed foods in six student halls of residence, some temporary restaurants of Islamic University, Kushtia were assessed for bacterial contamination by standard methods. Identification and characterization of E. coli isolates were performed using IMViC tests. Genomic DNA was used to perform RFLP pattern analysis.   Results: Thirty seven out of 50 (74%) examined samples of RTE foods had E. coli contamination. The highest number of E. coli was isolated from vegetable oriented RTE foods (90.90%) and fish, meat and cereals samples were also significantly E. coli positive. RFLP profiling of two E. coli isolates were observed.   Conclusion: The results of this study provide evidence that some RTE foods had unsatisfactory levels of contamination with E. coli. Thus street vended RTE food could be important potential vehicles for food-borne diseases. Molecular characterization may be exploited to identify food borne pathogen among different species.  Keywords: Ready-to-eat foods; Escherichia coli; RFLP pattern DOI: http://dx.doi.org/10.3329/jbs.v18i0.8783 JBS 2010; 18(0): 99-103


1979 ◽  
Vol 34 (3) ◽  
pp. 269-279 ◽  
Author(s):  
Sylvia Brabbs ◽  
J. R. Warr

SUMMARYFive clones of Chinese hamster ovary cells with increased resistance to bleomycin have been isolated following ethylmethanesulphonate mutagenesis. Resistance was stable in three of the clones, but unstable in the other two. One of the stably resistant clones was cross resistant to unrelated drugs, and in contrast to the parental cells, its response to bleomycin was potentiated by tween 80. These two observations suggested a membrane alteration in the resistant clone. There was no significant difference in bleomycin-inactivating enzyme activity between the parental and resistant clones.


2023 ◽  
Vol 83 ◽  
Author(s):  
M. Mushtaq ◽  
S. M. Bukhari ◽  
S. Ahmad ◽  
A. Khattak ◽  
M. B. Chattha ◽  
...  

Abstract There is a paucity of research conducted on microbial prevalence in pheasants. The microbiota of captive birds has zoonotic significance and must be characterize. Present study is therefore planned to assess the microbiota from oral, fecal and gut content of captive avian species. It will be helpful in characterization of harmful microbes. Different samples taken from oral, gut and feces of ring-necked pheasants (Phasianus colchicus), green pheasants (Phasianus versicolor), golden pheasant (Chrysolophus pictus) and silver pheasant (Lophura nycthemera). Samples were collected, diluted, and inoculated onto different agar plates (MacConkey, SS agar, MSA and nutrient agar) for cultivation of bacterial species. Colonies of E.coli, Staphylococcus spp. Brachyspira spp. and Campylobacter spp were observed based on colony morphology. Colony forming unit showed E. coli as frequently found bacteria in fecal, oral and gut contents of all the above pheasants. The overall significance difference was found among bacterial species of golden pheasants, green pheasant, ring-necked pheasant, and silver pheasants. It was concluded that E.coli is predominant isolated from heathy pheasants followed by Campylobacter, Staphylococcus and Brachyspira.


Author(s):  
Ajay S. Arya ◽  
Minh T. H. Hang ◽  
Mark A. Eiteman

Bacteria were isolated from wastewater and soil containing charred wood remnants based on their ability to use levoglucosan as a sole carbon source and on their levoglucosan dehydrogenase (LGDH) activity. On the basis of their 16S rRNA gene sequences, these bacteria represented diverse genera of Microbacterium, Paenibacillus , Shinella , and Klebsiella . Genomic sequencing of the isolates verified that two isolates represented novel species, Paenibacillus athensensis MEC069 T and Shinella sumterensis MEC087 T , while the remaining isolates were closely related to either Microbacterium lacusdiani or Klebsiella pneumoniae . The genetic sequence of LGDH, lgdA , was found in the genomes of these four isolates as well as Pseudarthrobacter phenanthrenivorans Sphe3. The identity of the P. phenanthrenivorans LGDH was experimentally verified following recombinant expression in E. coli . Comparison of the putative genes surrounding lgdA in the isolate genomes indicated that several other gene products facilitate the bacterial catabolism of levoglucosan, including a putative sugar isomerase and several transport proteins. Importance Levoglucosan is the most prevalent soluble carbohydrate remaining after high temperature pyrolysis of lignocellulosic biomass, but it is not fermented by typical production microbes such as Escherichia coli and Saccharomyces cerevisiae . A few fungi metabolize levoglucosan via the enzyme levoglucosan kinase, while several bacteria metabolize levoglucosan via levoglucosan dehydrogenase. This study describes the isolation and characterization of four bacterial species which degrade levoglucosan. Each isolate is shown to contain several genes within an operon involved in levoglucosan degradation, furthering our understanding of bacteria which metabolize levoglucosan.


Microbiology ◽  
2021 ◽  
Vol 167 (9) ◽  
Author(s):  
Nirbhay Singh ◽  
Anu Chauhan ◽  
Ram Kumar ◽  
Sudheer Kumar Singh

Branched-chain amino acids (BCAAs) are essential amino acids, but their biosynthetic pathway is absent in mammals. Ketol-acid reductoisomerase (IlvC) is a BCAA biosynthetic enzyme that is coded by Rv3001c in Mycobacterium tuberculosis H37Rv (Mtb-Rv) and MRA_3031 in M. tuberculosis H37Ra (Mtb-Ra). IlvCs are essential in Mtb-Rv as well as in Escherichia coli . Compared to wild-type and IlvC-complemented Mtb-Ra strains, IlvC knockdown strain showed reduced survival at low pH and under low pH+starvation stress conditions. Further, increased expression of IlvC was observed under low pH and starvation stress conditions. Confirmation of a role for IlvC in pH and starvation stress was achieved by developing E. coli BL21(DE3) IlvC knockout, which was defective for growth in M9 minimal medium, but growth could be rescued by isoleucine and valine supplementation. Growth was also restored by complementing with over-expressing constructs of Mtb-Ra and E. coli IlvCs. The E. coli knockout also had a survival deficit at pH=5.5 and 4.5 and was more susceptible to killing at pH=3.0. The biochemical characterization of Mtb-Ra and E. coli IlvCs confirmed that both have NADPH-dependent activity. In conclusion, this study demonstrates the functional complementation of E. coli IlvC by Mtb-Ra IlvC and also suggests that IlvC has a role in tolerance to low pH and starvation stress.


1980 ◽  
Vol 35 (3-4) ◽  
pp. 209-212 ◽  
Author(s):  
B. Schöbel ◽  
W. Pollmann

Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split chloro­genic acid. The isoelectric focusing reveals several isoenzymes of chlorogenase within a pI-range of 4.0-4.5.


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