Nepal Journal of Biotechnology
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Antibiogram of Escherichia coli and Staphylococcus aureus Isolated from Milk Sold in Kathmandu District
Full text linkThe emergence of antibiotic resistance in microorganisms and the presence of such isolates in milk pose a great risk to public health. Therefore, this study aims to determine the antibiotic susceptibility pattern of Escherichia coli and Staphylococcus aureus isolated from milk and assess the microbial quality of milk. For this, a total of 70 milk samples were collected and the total bacterial count (TBC) was determined. E. coli and S. aureus were isolated using their respective selective media while antibiotic susceptibility testing was carried out by Kirby Bauer Disc Diffusion method. The TBC showed that the raw milk samples contained two-fold higher microbial load while the pasteurized milk samples contained four-fold higher microbial loads than the standard guidelines. A total of 62 isolates were identified from culture-positive milk samples of which 32 were E. coli and 30 were S. aureus. A significant correlation was observed between microbial load and the organism isolated (r = 0.339, p<0.01). All S. aureus isolates were susceptible to Chloramphenicol while 40% were resistant to Cefoxitin, indicating the presence of Methicillin resistant S. aureus (MRSA). Also, 12 multidrug resistant (MDR) S. aureus were identified. While for E. coli, all were susceptible to Chloramphenicol but resistant to Ampicillin. Also, 9 MDR E. coli were detected. Higher resistance was observed among isolates from the raw milk samples than the pasteurized milk. It can be concluded that the milk produced by small-scale farms and dairy industries of Kathmandu district are of poor quality. Hence, routine microbial quality assessment and antimicrobial resistance monitoring should be followed to safeguard public health
Phytochemical Evaluation, Antioxidant and Antimicrobial Activities of Various Extracts from Leaves and Stems of Bryophyllum pinnatum
Full text linkAntioxidant and antimicrobial activities of different extracts (methanol and ethyl acetate) of leaf and stem of Bryophyllum pinnatum were studied. The screening for the secondary metabolites was carried out using the standard methods. The antioxidant capacities of the different extracts were assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and Ferric reducing antioxidant power (FRAP) while the antimicrobial activity of the extracts obtained were screened against Gram-positive, Gram-negative bacteria and fungi (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa Salmonella spp., Vibrio cholerae, Candida albicans and Aspergillus niger) using Agar well diffusion method. Both extracts obtained from leaf and stem of Bryophyllum pinnatum contained most of the phytochemical compounds tested for. However, anthocyanins and anthraquinone were not detected in leaf extracts while coumarin was absent in stem extracts. Quantification of bioactive compounds showed that both extracts contained the highest concentration of polyphenols (34.49 ±0.47 mg GAE/g and 32.32 ±1.2 mg GAE/g for methanol leaf and stem extracts respectively) while the least concentration was recorded for alkaloids (0.03±0.02 mg/g for methanol stem extract). Results revealed that the extracts showed dose-dependent scavenging of DPPH as well as the ability of the extracts to reduce FeCl3 solution, with methanol extracts exhibiting the highest scavenging and reducing capacity. However the leaves of Bryophyllum pinnatum had greater antioxidant activity than the stem by DPPH and ferric reducing assays, with IC50 values ranging from 3.147µg/ml to 3.80µg/ml for DPPH and 331.9 - 451 µg/ml for FRAP assays. The antimicrobial activity of various solvent extracts of leaf and stem reveal that microorganisms exhibited different sensitivities towards these extracts in a dose-dependent manner. Methanol leaf extract showed no activity against Escherichia coli while Pseudomonas aeruginosa was insensitive to ethyl acetate leaf extract. For stem extracts, Aspergillus niger, Vibrio cholerae and Pseudomonas aeruginosa were resistant to methanol extract while Aspergillus niger, Salmonella spp. and Pseudomonas aeruginosa was resistant towards ethyl acetate stem extract. The results obtained in this study showed that Bryophyllum pinnatum is a reservoir of bioactive compounds and both extracts exhibited significant antimicrobial and antioxidant activity
Biofuel Production from Waste Cooking Oils and its Physicochemical Properties in Comparison to Petrodiesel
Full text linkHaphazard mining and consumption of fossil fuels have reduced petroleum reserves causing fossil fuel depletion and environmental degradation; thus, reflecting the need for the cheaper, renewable and eco-friendly alternative source of petroleum to meet the fuel demand. A million liters of edible oil used for cooking foods and date expired oils from oil manufacturers are discarded into sewage. This study primarily intends to study the feasibility of biodiesel production using such waste oils. In this work, biodiesel was prepared from waste cooking oils by a process called transesterification with NaOH as a catalyst. Our results showed that methyl ester (biodiesel) (92.67±0.90%), soap materials (1.33±0.224%), and glycerol (6±0.68%) were obtained after the transesterification of waste cooking oil. The physicochemical properties of biodiesel such as density, viscosity, volatility, surface tension, and flashpoint were analyzed, which were found to be 0.862±0.006 g/cm3, 2.23±0.021 cP, 0.327×10-3±4.5×10-6 g/s, 32.03±0.138 dyne/cm, 169.67±0.810°C, respectively. These properties were compared with that of commercial diesel as well as with the values specified by the American Society for Testing and Materials (ASTM) D6751. The density and the surface tension of the biodiesel were found similar to that of petrodiesel but its volatility was 3 times lower. Fourier-transform infrared spectroscopy (FTIR) spectra of the biodiesel showed methyl ester functional group at 1436 cm-1. Based on the cost of the materials used for production, the cost of biodiesel was estimated to be about 81 Nepalese rupees (0.67 USD) per liter. The properties of biodiesel also met the standard values of ASTM D6751. These findings indicate that waste oil is one of the feasible biodiesel sources and it can be used as a suitable alternative to petrodiesel
Screening of Actinomycetes from Soil for Antibacterial Activity
Full text linkActinomycetes are Gram positive, free living saprophytes which are distributed in soil as one of the major populations and are primary source of antibiotics. This study was carried out with a quest to isolate actinomycetes from soil samples of different places and assess their antibacterial activity. Isolation of actinomycetes was carried out by serial dilution of soil sample followed by spread plate method. The antimicrobial extract was extracted using ethyl acetate. Assessment of antimicrobial activity was performed by using Agar cup plate assay against test organisms (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Salmonella paratyphi, Bacillus subtilis, Staphylococcus aureus). Antibacterial activity was tested against Methicillin Sensitive Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus in the isolates having effective inhibitory activity against Staphylococcus aureus. From 15 soil samples of 12 different locations, 121 actinomycetes isolates were isolated. Among them, 58 (47.9%) isolates were inhibitory against at least 1 test organism in primary screening, of which 22 isolates effective against more than 1 test organism was chosen for secondary screening. Out of them, 8 were inhibitory against 2 test organisms while 14 were inhibitory against 3 test organisms. Staphylococcus aureus was found to be the most susceptible test organism with its susceptibility against 12 actinomycetes isolates. Among 12 isolates effective against Staphylococcus aureus, 10 were found to have an inhibitory effect against Methicillin Susceptible Staphylococcus aureus while 6 were found to have inhibitory effect against Methicillin Resistant Staphylococcus aureus strain. The findings of this study highlight the inhibitory potential of actinomycetes and the need for further investigation for obtaining novel antimicrobial agents from actinomycetes from various unexplored areas
Phytochemicals Levels and Antioxidant Capacities of Figs Flowers Fruits
Full text linkSince antiquity, phenolic compounds produced by plants were known as free radical scavengers and as powerful antioxidants. Huge interest has been made by researchers to the traditional uses of medicinal plants against illnesses related to oxidative stress. This study measures the correlation that can be existed between the antioxidant capacity and phytochemical s levels of four varieties of Ficus carica fruits, figs flowers or "Bakor" as called locally in Algeria. Therefore, extracts were assessed for determining their antioxidative potentials using both test of total antioxidant capacity and DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging test followed by quantitative phytochemical analysis to estimate the total flavonoid level (TFL), the total phenolic level (TPL), the total anthocyanin level (TAL) and the condensed tannins level of plants methanolic extracts. A positive correlation was observed between phenolics content and the antioxidant capacity of figs flowers methanol extracts. The methanolic extract of Bechar (MeOH Var.2) chelated 87,9± 1,23 % of the DPPH free radical with IC50 value equal to 0,185 mg/g DW. A high antioxidant ability of almost all extracts is, probably, related to the appreciable rates of flavonoids, phenolics and tannins showed by those fig extracts. The highest value of phenolics level was detected among the variety 1 methanolic extract of Bechar (MeOH Var.1) of 10,4 mg GAE/g DW
Regeneration Technique of Bamboo Species through Nodal Segments: A Review
Full text linkMicropropagation is an alternative technique to propagate at large scale plants to meet global plant demand. Various researchers have worked on the micropropagation technique to regenerate bamboo species by using nodal segments from years. Contamination, browning, necrosis, and acclimatization with physiological stress are the extreme problems of the micropropagation technique. But, many numbers of papers have been published on micropropagation of the bamboo species through nodal segments as explants. The proliferation of the bamboo shoots is dependent on the season of collection, size of explants, the position of explants, diversity of plants, concentration and combination of plant growth regulators, most adequate culture medium, environmental condition of the equipment, handling, and individual species. Bamboo is a monocarpic fast-growing, tall perennial grass and having the high potential to generate economic and social benefits. It helps to maintain land patterns and control soil erosion. The long life cycle of the bamboo produces a huge amount of seeds but unfortunately, mostly, they are non-viable. So, bamboos are propagated from vegetative by cutting and air layering. However, these methods are only for a small scale and they also tend to destroy large mother plant stocks and difficult to be transported. So, the in vitro propagation technique is useful to obtain large progenies from desired genotypes. Mostly, BAP and TDZ growth hormones are widely used for shoot multiplication and IBA, NAA and IAA are used for root initiation as per developed protocols in tissue culture for large scale production. This review intends to explore an overview of the recent literature reports to summarize the importance of micropropagation by using nodal segments of bamboo species and factors influencing it
Selection of Pyramided Barley Advanced Lines for Stripe Rust, Leaf Rust and Crown Rust Diseases Using Molecular Markers
Full text linkBarley diseases are the major yield limiting factors for barley cultivation in Nepal. Stripe/Yellow rust (P. striformis f.sp. hordei and P. striformis f.sp. tritici), leaf rust (Puccinia hordei), and crown rust (P. coronata) are the major rust diseases in Nepal. Pyramiding resistance genes against all these rust diseases are possible through molecular marker assisted breeding. Sweden originated barley variety ‘Bonus’ is found resistant to stripe rust and having linked microsatellite markers for stripe rust and crown rust resistance. Similarly, Nepalese hull-less barley variety ‘Solu Uwa’ and Nepalese awn-less barley landrace NPGR Acc# 2478 have linked microsatellite markers for leaf rust resistance. Therefore, one polymorphic sequence tagged sites (STS) marker (ABG054) for stripe rust resistance, two polymorphic simple sequence repeats (SSR) markers (Bmac0144h and HVM049) for leaf rust and one polymorphic SSR marker (Bmag0006) for crown rust resistance were used to select the advanced barley lines (at F8 stage) from above parents. Field screening of stripe rust resistance was also conducted. Among 51 advanced and field disease resistance lines from Bonus/Solu Uwa cross, we have selected 10 pyramided lines for all three types of barley rust resistance. Similarly, among 39 advanced and field disease resistance lines from Bonus/NPGR Acc#2478 cross we have selected three pyramided lines and advanced for further yield testing for general cultivation purpose. The chances of losing the desired gene are high in late generation selection using molecular marker assisted selection (MAS); but the chances of getting agronomically superior varietal output will also increase
Genetic Diversity in Finger Millet Landraces revealed by RAPD and SSR Markers
Full text linkGenetic diversity assessment is the preliminary work for development of variety and conservation of diversity. Finger millet is a very important crop in Nepal however, its genetic potential has not been fully utilized. Genetic diversity was assessed in forty landraces of finger millet using 9 RAPD and 5 SSR markers. These landraces were collected from Kaski and Dhading districts. None of single primers of these RAPD and SSR could separate all 40 landraces. The average number of bands were 6.33 and 7.8 per RAPD and SSR primers respectively. Mean polymorphism information content was of 0.314 for RAPD and 0.37 for SSR. Primer OPA-4 produced the highest number of bands and the lowest numbers of bands were produced by OPA-16. Among the SSR primers, SSR-06 produced the highest number of polymorphic bands and UGEP-53 produced the lowest bands. RAPD based dendrogram has generated four clusters and SSR based dendrogram has generated two clusters. In both dendrogram and principal component analyses, Purbeli landrace was found unique locating separately in the cluster and scatter plot. Nei\u27s genetic distance produced by RAPD and SSR primers was similar that is 0.327 by RAPD and 0.296 by SSR markers. Genetic distance produced by SSR markers was higher than distance produced by RAPD marker. These landraces were from two districts and therefore have shown intermediate diversity. These molecular marker-based findings should would be more useful if we could link with agromorphological traits. Inclusion of large number of landraces collected from different areas are required to get higher level diversity in addition to associate genetic diversity with geographical sites. Groupings of these landraces could be useful for selecting landraces in breeding program as well as planning conservation program
Standardization of Ayurvedic Drug- Nyctanthes arbor-tristis, Hippophae salicifolia, Ocimum tenuiflorum and Reinwardtia indica and Combined Herb-Herb
Full text linkThe herbal medicines have reached extensive acceptability as therapeutic agents for various clinical diseases due to global demand. Therefore, standardization is the essential and initial step to drug development. It is for the establishment of consistent biological activity, a consistent chemical profile and biomarker identification. It improves the safety and efficacy of herbal medicine to provide the best herbal medicine to society and increase popularity rather than non-standardized extracts. In addition, it is essential to practice or maintain a quality assurance program for the production and manufacturing of herbal medicine that includes the basis of organoleptic characters and photomicrographs, physicochemical, proximate analysis phytochemical evaluation and quality control analysis and order to assess the quality of drugs, based on the concentration of their active principles. WHO has provided specific guidelines for the assessment of the safety, efficacy and quality of herbal drugs as a prerequisite for global harmonization and of utmost importance. In the present study, the herbal extracts were cleaned, dried in the shade and powdered by passing through the sieve as per the method described in the standard protocol. An overview covering various techniques employed in the extraction and characterization of Nyctanthes arbortristis, Hippophae salicifolia, Ocimum tenuiflorum and Reinwardtia indica, standardization is reported in this study. The obtained data would be very significant for future clinical aspects, as the bioactive molecules present in the extracts may exhibit synergistic effect with other bioactive compound and show a better therapeutic value. Thus, this study provides standardized and therapeutically potential data of active polyherbal formulations for the different ailments
Comparative Study of Bioactive Compounds in Different Varieties of Pears in Nepal
Full text linkThis study was conducted to evaluate the physicochemical parameters, perform qualitative tests (for sugars and phytochemicals), and quantitative tests (phenolics, antioxidants, anthocyanins, tannins, vitamin C) of six different varieties of pears i.e. Bartlette, Chinese pears, Chojuro, Kosui, Pharping local, and Yakumo. The juices extracted from respective pears were used for the analysis. The phenols were determined by the Folin-Ciocalteu method, antioxidants by the DPPH scavenging activity, and anthocyanins by a SO2 bleaching technique. The Pharping local pears were found to have the highest anthocyanins (85.95±0.1 mg/l), total phenolic content (600±0.01 mg GAE/l), antioxidants (IC50 value 250±0.00 mg of phenol/l) and vitamin C content (12.2±0.01 mg/100 ml) and tannins were observed to be highest in Yakumo pears (0.93±0.01 g/l). Likewise, the highest clarity i.e. 1.960±0.00 was observed in Bartlette pears and the highest acidity (2.01±0.01%) in Chojuro pears. Various sugar/carbohydrate tests like Molisch’s test, Benedict’s test, Barfoed test, Bial’s test, Seliwanoff test, Fehling’s test and Iodine test were performed for the pear varieties. All the pears gave positive results for all the sugar tests except Iodine test. The positive results for sugar/carbohydrate signifies the presence of various sugars that help for the better taste, texture, and aroma of pear. The pear varieties showed the presence of phytochemicals like flavonoids, terpenoids, catechins, cyclic glycosides, and proteins. The phytochemicals are responsible for fruit preservation and act as anti-carcinogenic components. Among the varieties of pears, Pharping local pears were observed to be most nutritional because of high antioxidants, phenols, anthocyanins, and vitamin C