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Effects Heavy metals and NaCl on Growth and Aldh Experession in Lycopersicum Esculentum Var Srijasna
(2012) Bhatt, Padam Shekhar; Tribikram Bhattarai
A greenhouse pot experiment was conducted to determine the effects of heavy metals (Cd, Pb) and NaCl on growth morphology, accumulation, and ALDH expression in Lycopersicumesculentum Var Srijana. The experiments were performed to examine the effects on the seed germination, root elongation, shoot elongation, Al dehyde dehydrogenase (ALDH) expression and accumulation of Pb, Cd and Na in the selected tomato variety grown on soil-verm icompost substrate supplemented with different concentration of Pb(NO3)2, CdCl2and NaCl. The selected heavy metals were treated in different concentrations ranging from 0.1, 0.3, 0.5, 1 mM and salt (NaCl) in 25, 50, 75, 100 mM separately in soil – vermicom post media (2:1) in plastic pots. The seed germination, root and shoot growth were affected by these treatments at higher concentrations. The increasing concentrations of heavy metals and salt treatments have in hibitory effects on germination, root length (RL), shoot length (SL)thoughthe plants seemto germinate and grow efficiently at all treatments.Treatments at lower concentration of Pb(NO3)2(at 0.3, 0.5mM) and of salt (at 50 mM) doses, were found to be stimulating the root and shoot elongation whereasat higher concentration of heavy metals(at 1 mM of Pb(NO3)2, CdCl2) andNaCl (at 75mM, 100mM) causes the delayed germination and retardationin root and shoot length.Aldehyde dehydro genases (ALDHs) play a major role inthe detoxification processes of aldehydes generated inplants in various metabolism and when exposed to abiotic stress. ALDH catalyzes the oxidation of the chemically toxic aldehydes intermediates into corresponding carboxylic acids, reducing pyridine nucleotide. The simplest method of ALDH assay is spectrophotometric method and is used in this study. The spectrophotometric reading showed to have highest activity (693.39 mIU/mg proteins) at 0.3 mM CdCl2 treatment after2ndweek of stress exposure. It was also found that the lower doses of stresses are more efficient at inducing greater ALDH responses than higher doses which shows lower ALDH activity. NATIVE-PAGE of the same prepared samples showed some bandswhich confirmed that the spectrophotometric measurements was of ALDH. The number, type and character of the isotypes of ALDH produced but couldn’t be characterized.Some additional bandsin treatment plant tissue homogenate samplescan be regarded as produced due to stress exposure. The metal accumulation experiments performedunder stress ofPb(NO3)2, CdCl2and NaCl suggests that their uptake takes place at all treatments. The metals were determined by using atomic absorption spectrophometry (AAS). Highest uptake of heavy metal occurs at 1mMPb(NO3)2 and Na at 100mMNaCltreatments and least accumulation occurs at 0.1 mMPb(NO3)2 and 25 mMNaCl.From this study, it can also be concluded that the amount of accumulation increases as the concentration of heavy metals and Na increases in the substrate.
Aldehyde dehydrogenase, Lycopersicumesculentum var Srijana, Abiotic stress, Heavy metals, Uptake
Enzymes Inhibition and Antioxidont Assay of Enthno Medicinal Plants of Nepal
(2017) Pokharel, Rupesh; Pragati Pradhan
In this research, both chemical and biological assays performed. Terminalia chebula, Terminalia
bellerica, and Eucalyptus alba were found to be effective against Staphylococcus aureus with
the zone of inhibition 18, 11 and 7 ug/ml respectively, rest of the selected plants were not
found to be active against Pseudomonas aeruginosa. Staphylococcus aureus has been found to
cause different disease like bacteremia, endocarditis, meningitis, skin infection and toxic shock
syndrome. Eucalyptus alba showed highest polyphenol content (138.86±9.62 mg GAE/g dry wt.)
while flavonoid content were even lower than polyphenol content while flavonoid content
were even lower than polyphenol content. Phytochemical screening showed presence of
tannins, polyphenol, flavonoids, and cardiac glycosides. IC 50 value of antioxidant activity for
most of the selected plants were below 50 µg/ml. Least IC 50
value was found to be of
Terminalia chebula that is 19.63±0.89 µg/ml. Such results indicated the efficacy against disease
due to free radical like rheumatic arthritis. In enzymatic assays, low IC50 values by Terminailia
chebula, Ampelocissus divaricata, Terminalia bellerica, Eucalyptus alba, and Woodfordia
fruticosa for inhibition of α-glucosidase and 15-lipoxygense indicated their efficacy against
disease due to free radicals like diabetes. Result of this research awares us about the use of
these medicinal plants.
Keywords: Medicinal plants, phytochemical screening, antioxidant, antibacterial activity,
enzymatic assays.
Enhanced Host Range and Reduction of Biofilm by Synergistic Effect of Phage Cocktails Isolated from Rivers of Kathmandu, Nepal
(2020) Gyanwali, Indu; Rajani Malla
Introduction: The world is running out of antibiotics and search for new therapeutic tools
to tackle this problem is a major concern worldwide. Using phages in therapeutics has
great potential to fight antimicrobial resistance, which can be a solution to this global
threat. Bacteriophages are viruses that specifically infect the bacterial host and lyse the
host bacteria during their lytic cycle. Phages in therapeutics has been investigated from
over a century, now it has been developed as a revitalized therapy. Narrow host range of
phages possess both benefits and limitations; highly specific phages may not harm
beneficial microbes while such phages cannot be effective to treat multi-bacterial
infections. Combination of different phages with complementary features are often used
to mitigate such issues. Concept of phage cocktails in treatment of infectious diseases is
the most highlighted topic in phage therapy. The use of different phages combined in
cocktails allows for the treatment of multiple pathogens, broadening the phages’ action
spectrum. In this study, we aimed to test the efficacy of phage cocktails to enhance host
range along with effective biofilm reduction.
Methodology: Phages were isolated from the river water using different clinical strains of
bacteria and were combined to make cocktails. Intraspecific and interspecific host range
with both individual phages and cocktails phages was assessed by spot assay and liquid
lysis assay/killing assay. Reduction of biofilm by individual phage and phage cocktails was
determined by crystal violet assay.
Results: From this research work, we found that Klebsiella phage cocktails were effective
against E. coli pathogenic strains. On multi host range analysis with individual and cocktail
Klebsiella phages, host range was enhanced by cocktails, which was confirmed by
efficiency of plating assay. Morphological identification of phages by TEM showed all the
Klebsiella phages were of Order Caudovirales and family Podoviridae. The maximum
bacterial growth inhibition was at 4 hours of infection, with phage cocktails, showing the
bacterial inhibition upto 50%. The bacteria used in our experiment were found to be
moderate biofilm producers and there was substantial reduction in biofilm with phage
cocktails as compared to individual phages.
Conclusion: The results indicate that the application of the phages in the form of a cocktail
have their potential to be used presumptively to control multi-bacterial infection. Phage
cocktails of Klebsiella pneumoniae can effectively lyse E. coli bacterial strains, though
different genus, than individual phages, along with effective biofilm reduction. With the
extensive research, such phage therapy can treat infection in-vitro; as an application to
treat multi-bacterial infections as well as such phage cocktails can be used as disinfectant
to decontaminate hospital indwelling devices.
Keywords: Antibiotic resistance, Bacteriophage, Biofilms, Host range, Phage cocktails