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Screening of Bacteriocin Production in Lactic Acid Bacteria Isolated From Fermented Dairy Products
No full textAims: In this study we aimed to screen LAB strains from different fermented dairy products by phenotypic and genotypic methods.
Methodology: 138 LAB isolates belonging to Enterococcus (13,76%), Lactococcus (18,84%) and Lactobacillus (67,39%) genera from fermented dairy products were used to search for their bacteriocin production and bacteriocin encoding genes were searched. LAB isolates were screened by spot-on lawn assay method against indicator microorganisms. Geobacillus stearothermophilus DSMZ 22, Escherichia coli ATCC 35218, Bacillus cereus, Listeria innocua, Listeria monocytogenes, Enterococcus faecalis, Micrococcus luteus, Lactococcus lactis DSMZ 20729 and Lactobacillus plantarum DSMZ 20205. Cell-free supernatants (CFS) of LABs used for agar-well diffusion assay to confirm antibacterial activity.
Results: All the LAB strains exhibited antibacterial activity against indicator bacteria at varying degrees by spot on lawn method. None of the CFS except one belong to positive control Lactococcus lactis DSMZ 20729 showed inhibitory effect by agar well diffusion assay. According to PCR results which used to investigate the bacteriocin genes of LAB’s , ent-A (5,07%), ent-B (2,17%), lcn-A (2,17%), and pln (1,44%) genes were detected in some of the isolates
Enhanced Protocol Development for in vitro Multiplication and Rooting of Vanilla (Vanilla planifolia Andr.) Clone (Van.2/05)
No full textVanilla (Vanilla planifolia Andr.) is a multipurpose spice in the world. The crop had been introduced to Ethiopia from Mauritius and it is still under maintenance at the Tepi National Spices Research Center (TNSRC). It is commonly propagated through stem cuttings which could arrests subsequent plant growth and development and serves as an ideal means for the spread of varied diseases. To solve the mentioned problems, no efficient in vitro protocol had so far been developed to propagate this vanilla clone in Ethiopia. Therefore, this study was initiated to address this gap by developing efficient protocol for the enhanced multiplication of this accession (Van.2/05). In this study plant material was taken from TNSRC. The experiments were carried out in Jimma Agricultural Research Center (JARC) at Biotechnology Laboratory. Nodal explants and Murashige and Skoog (MS) (1962), basal medium were used exclusively throughout the experiments. The experiments were laid out in Completely Randomized Design (CRD) with factorial treatment combinations and replicated three times for plant growth regulator (PGR) assisted experiments. In the study, shoot multiplication, the combined use of 2 mg l-1 6-Benzylamino Purine (BAP) and 0.5 mg l-1 Naphthalene Acetic Acid (NAA) was proved to be the best providing the highest shoot mean number (5.33) and length (4.9 cm) of shoots after five weeks of culture. The combined use of different MS basal medium strengths and Indol -3-Acetic Acid (IAA) concentrations were employed. Therefore, ½ MS strength combined with 0.5 mg l-1IAA produced mean number of 4.00 roots per plantlet with mean length of 6.1cm. The average rate of ex-vitro survival was 83.4%. Therefore, the advent of this protocol could have considerable value to enhance the expansion of vanilla cultivation in Ethiopia
Phytochemical Screening and Effect of Temperature on Proximate Analysis and Mineral Composition of Zingiber officinale Rosc.
No full textAims: To investigate the phytochemical composition and effect of temperature on the proximate and mineral composition of Zingiber officinale.
Study Design: Activity directed phytochemical screening, proximate analysis and mineral composition investigation of Z. officinale rhizomes using in vitro methods.
Place and Duration of Study: Medicinal Plants Section, Bioresources Development Centre, Ogbomoso, Nigeria between May and November, 2016.
Methodology: Fresh rhizome of Z. officinale was milled, extracted with absolute ethanol and screened for phytochemicals. Proximate and mineral analyses were carried out at various temperatures; room temperature (28°C; control), 40, 50 and 60°C.
Results: Phytochemicals including; alkaloid, tannins, saponins and cardiacglycosides were present in the rhizomes. The results showed significant (P< 0.05) decrease in the percentage of crude protein (9.53±0.04) at 60°C when compared with room temperature; control (9.62±0.04), increase in crude fiber and ash at 40°C (8.31±0.02 and 6.76±0.02 respectively) and 60°C (8.34±0.03 and 6.77±0.02 respectively) when compared with the control (8.28±0.15 and 6.74±0.01 respectively). The results also showed a significant (P< 0.05) decrease in the percentage of sodium (0.057±0.001 and 0.061±0.001) at 40 and 60°C respectively when compared with the control (0.064±0.002); potassium (1.65±0.01) at 40°C when compared with the control (1.73±0.02); magnesium and calcium at 40°C (0.197±0.002 and 0.083±0.001 respectively) when compared with the control (0.203±0.005 and 0.087±0.001 respectively).
Conclusion: The current study showed that drying at above room temperature does not affect the proximate and mineral composition of Z. officinale rhizomes. The presence of nutrients and phytochemicals in Z. officinale could be exploited for the overall well-being of man
Bacterial Synthesis of Silver Nanoparticles by Culture Free Supernatant of Lactic Acid Bacteria Isolated from Fermented Food Samples
No full textAim: Biosynthesis of silver nanoparticles (SNPs) using culture free supernatant (CFS) of Lactic acid bacteria (LAB).
Study Design: To biosynthesize, characterize and to determine the antibacterial potential of silver nanoparticle using culture free supernatant of lactic acid bacteria and to determine the effect of some parameters on SNPs biosynthesis.
Methodology: Biosynthesis and characterization of SNPs using CFS of LAB and the antibacterial activity.
Place and Duration of Study: Department of Microbiology, University of Ibadan, Ibadan, Oyo state, Nigeria between Jan to October 2016.
Results: The antibacterial potential of the CFS from the LABs was evaluated on some pathogenic bacteria and antibacterial activity ranged from 0 – 20 mm. The two LAB strains LPW2 and LPF6 had 93% and 86% relatedness to Lactobacillus casei strain WK2G-3A and Lactobacillus fermentum strain E10-15. The CFS of the LAB strains and AgNO3 was able to produce SNPs. The biosynthesized SNPs had a strong Surface Plasmon Resonance (SPR) peak at 500 nm, varying shape (partially aggregated particles) and the sizes ranged from 0.7 - 10.0 nm and 1.4 – 10.0 nm for CFS SNPs from Lactobacillus casei and Lactobacillus fermentum. Carboxylic acid, protein, aldehydes, ester and hydroxyl groups are the functional groups responsible for SNPs formation. The antibacterial activity of the SNPs ranged from 11 – 29 mm. Bacillus sp. and Streptococcus pyogenes were found to be more susceptible to the biosynthesized SNPs. 28°C, pH 4 and 10 Mm AgNO3 supported the highest SNPs production.
Conclusion: In conclusion the CFS from the LABs biosynthesized SNPs which exhibited antibacterial activity against some pathogenic microorganisms
Properties of Alpha-amylase of Lactobacillus plantarum Isolated from Cassava Waste Samples
No full textThe search for various industrial enzymes including starch degrading enzymes has received a great deal of attention for their perceived technological and economic benefits. Alpha-amylase has been produced from large varieties of organisms including pathogenic ones which are not Generally Regarded as Safe (GRAS). In this study, a total of Thirty nine (39) lactic acid bacteria were isolated from the different cassava waste samples (peels, cassava waste water, fibre and soil). The isolates were screened for their ability to produce α-amylase on starch agar. The amylolytic activity of the selected isolates was determined using starch-iodine complex while the enzymes were characterized based on parameters such as pH, temperature, substrate concentration, and metal ions. Upon starch hydrolysis, 29.9% of the LAB isolates demonstrated amylolytic properties with L. plantarum having the highest occurrence. The selected amylase producer was identified both phenotypically and molecularly as L. plantarum S7. Enzyme production was found to be highest (10.573U/ml) at 30 hours of incubation. Optimum temperature and pH for the enzyme activity was found to be 40°C and 7 respectively. The α-amylase retained more than 50% of it residual activity at pH 7 and 8 after preincubation for 90mins. Calcium chloride (CaCl₂) and Ammonium disulphate (NH₄ (SO₄)₂) enhanced amylase activity however, the activity was inhibited at 5mM molar concentration by KCl, BaCl₂, CuSO₄, NaCl, EDTA (10%) and Urea (10%). The genomic level confirmation was done with 16s rDNA and the sequence showed 90% sequence similarity with L. plantarum
Insights on Pharmacological Properties of Combretum leprosum Mart.
No full textCombretum leprosum Mart. is a plant widely used in folk medicine; several studies revealed anti-inflammatory, antinociceptive, toxic, antiproliferative, antibacterial, antiparasitic, neuroprotective and gastroprotective effects, among other properties. However, there are no reports on evaluation of preparations obtained from this species’ tissues, exploring biological responses of macromolecular components, such as proteins, common active agents. Proteins, such as lectins, promote important pharmacological results due to specific interaction with carbohydrates or glycoconjugates. In this work, a protein fraction obtained from a saline extract of C. leprosum leaves was evaluated for anti-inflammatory potential in a paw edema assay induced by carrageenan in Wistar rats. A significant anti-edematous effect was observed after 3 h (100 mg protein/kg) and 6 h (30 mg/kg and 100 mg/kg). The saline extract and protein fractions showed lectin activity, inhibited by D-(+)-mannose, D-(+)-trehalose dihydrate, D-(+)-galactose and D-fructose. Conclusively, leaves of C. leprosum contained proteins and lectin(s), promising anti-inflammatory agents. A vision of C. leprosum pharmacological properties is also approached
Antimicrobial Resistance and Detection of Biofilm in Staphylococcus aureus Isolates from Casablanca
No full textAims: The ability of biofilm formation seems to play an essential role in the virulence of Staphylococcus aureus. The aims of the present study were to test the sensitivity of the clinical isolates of Staphylococcus aureus to antibiotics, detect the ability of these strains to form biofilm and evaluate the correlation between biofilm formation by clinical isolates and the resistance to antibiotics.
Place and Duration of Study: Laboratory of Virology, Microbiology and Quality/ Eco-toxicology and Biodiversity, Faculty of Sciences and Techniques Mohammedia, University Hassan II Casablanca and laboratory of Bacteriology, Virology and Hygiene, Ibn Rochd University Hospital, Casablanca during October 2015 and January 2016.
Methodology: A total of 117 clinical isolates of staphylococci were collected at the University Hospital Ibn Rochd of Casablanca, Morocco and examined for antimicrobial susceptibility, presence of mecA gene and biofilm formation. Staphylococci species identification and antibiogram were performed by standard procedures using disk diffusion method. The methicillin resistance was confirmed by PCR using mecA specific primers. The biofilm formation assay was realised by the tissue culture plate method (TCP).
Results: Among all strains collected, 74 were identified as Staphylococcus aureus. Out of 74 Staphylococcus aureus, 22 strains (29.7 %) were found methicillin resistant when tested with cefoxitin disc diffusion method. 20.3 %, 18.9 % and 13.5 % were classified as resistant to kanamicin, ciprofloxacin and erythromycin respectively. All strains were found resistant to penicillin G and sensitive to teicoplanin. All isolates resistant to methicillin by cefoxitin disc diffusion method were confirmed by presence the mecA gene by PCR. Of the 74 isolates 16 (21.6 %) were non adherent, 40 (54 %) weakly adherent, 12 (16.2 %) moderately adherent and 6 (8.1 %) strongly adherent.
Conclusion: The results of this study showed that there is a correlation between biofilm formation and resistance to all the antibiotics tested, except to teicoplanin, which was active against the all strains
In vitro Propagation of Oxytenanthera abyssinica (A. Rich. Munro) from Seed Culture
No full textIntroduction: In Ethiopia, O. abyssinica has varies economic importance. However, conventional propagation methods of O. abyssinica are generally inefficient due to their low multiplication rate, time consuming, labor intensive, and too costly.
Aims: The objective of this study was to develop a protocol for micropropagation of O. abyssinica through seed culture.
Methodology: For seed disinfection, NaOCl of 3, 4, and 5% concentration for 15, 20, and 25 min exposure time were tested. MS medium augmented with BAP or KN at different concentrations was used for shoot initiation and multiplication. For in vitro rooting, ½MS medium supplemented with IBA or NAA at different concentrations was used. Data were subjected to ANOVA and mean values were compared using LSD at a 5% of probability level.
Results: Seeds disinfected in 4.0% NaOCl for 25 minutes gave 71.6% clean explants and 23.45% germinated explants. In shoot initiation experiment all viable seeds were able to proliferate in 5-7 days of culturing in all treatments; and 4.0 mg dm^-3 BAP was found better in maximum shoot initiation percent (86.67) and mean number of shoots per explants (4.8). Similarly, in shoot multiplication 4.0 mg dm^-3 BAP was effective in highest mean number of shoot (11.33) and multiplication rate (3.77). The maximum rooting percent (93.33) and maximum root number per clump (9.42) were found at 8.0 mg dm^-3 IBA. Finally, the survival rate of plantlets in greenhouse condition was found to be 91.67% after 30 days of acclimatization.
Conclusion: The study enables to develop an effective and applicable protocol for O. abyssinica micropropagtion
Influence of Mulching on Growth and Yield of Tomato (Solanum lycopersicum L.) under Protected Environment
No full textAims: To determine the effect of various mulches on growth and yield of tomato and to work out the economics of cultivation under protected environment.
Study Design: Randomized Block Design with three replications.
Place and Duration of Study: Research farm, Department of Vegetable Science and Floriculture, CSK HPKV, Palampur during 2016 and 2016-17.
Methodology: The experiment consists of nine different mulch treatments. The observations were recorded viz., days to 50 per cent flowering, days to first harvest, number of nodes/plant, internodal length, plant height, number of fruits/plant, average fruit weight, yield per meter square, harvest duration, net returns and output: input ratio. Observations were recorded on 5 plants chosen at random in each entry and replication.
Results: Significantly highest fruit yield of 10.9 kg/m2 was obtained in M7 i.e. double shaded plastic mulch and was statistically at par with M6 i.e. black colour plastic mulch (10.2 kg/m2). Mulch showed significant variation in a number of fruits/plant. M7 i.e. double shaded plastic mulch (40.4) remained statistically at par with M6 (39.5) and M1 (38.6) produced significantly more number of fruits/plant. Significantly highest net returns (Rs.147.6/m2) were observed in M7, as compared to other mulches.
Conclusion: It can be concluded that use of double shaded and black colour synthetic mulch significantly increased the growth, yield and yield contributing characters in addition to net returns in tomato under the protected environment
Production of Monoclonal Specific Antibody against Brazzein Fusion Protein
No full textBackground: The use of a natural sweet protein is important as an attractive alternative to sucrose in the human diet. Rigorous research has identified the use of the artificial sweetener that leads to various diseases, cancer and heart disease. Many functional studies are necessary for examining the structure and biological activity of natural sweeteners such as Brazzein and its receptor targeting. In this report, we produced a panel of monoclonal antibodies against the recombinant brazzein which can be used for functional studies.
Methods: Hybridomas cell fusion technology was used for the production of monoclonal antibody. BALB/c mice were immunized twice with purified fusion proteins with Freund adjuvant. Next, 14 days after the last injection, blood sample was collected from the eye and serum was separated and the antibody titer was detected by enzyme-linked immunosorbent assay (ELISA). The mouse with the highest antibody titers was selected. Seven days before fusion, the selected mouse was boosted with 50 µg antigen into the peritoneum to develop a robust immune response and then spleen cells were isolated from the same animal for fusion to myeloma SP2/0 to generate hybridoma cells.
Results: Hybridoma clones were screened by ELISA and their monoclonal antibodies were purified. Specificity and reactivity of the monoclonal antibodies were determined by western blot analysis. We produced a panel of monoclonal antibodies that were highly specific and reacted with Brazzein protein that was detected by western blot analysis.
Conclusion: These monoclonal antibodies bind to the MBP (Maltose binding protein)-containing recombinant protein in western blotting, so this antibody can be a useful probe for tracing proteins in basic research and pharmaceutical applications