Direct Organogenesis of Citrus Cultivars from Shoot Tip Nodal Segments.

BACKGROUND: Citrus cultivar improvement via conventional breeding strategies is impeded by factors related to its reproductive biology. The orange is a hybrid between pomelo (Citrus maxima) and mandarin (Citrus reticulata). Among various orange cultivars, Valencia oranges have a bit of bitter tang mixed in with their sweetness, as Navel oranges are, the most widely cultivated citrus species, quite sweeter, and also don't contain any seeds. Tangelo mandarin orange cultivar is a hybrid of C. reticulata × C. maxima or × C. paradisi. OBJECTIVE: The present study was undertaken to optimize the hormonal composition of the media with regard to plant growth regulators for in vitro propagation of sweet orange cultivars from nodal segment explants. METHODS: The nodal segment explants were collected from three citrus cultivars, Washington Navel, Valencia and Tangelo. Murashige and Skoog (MS) medium supplemented with sucrose and different concentrations of growth regulators was used for shoot proliferation and root induction, and the optimum medium composition was assessed. The patent for Citrus Tissue Culture was obtained from the Office of Research Affairs, Haramaya University. RESULTS: The results indicate that the highest shoot response was recorded for Washington's navel with maximum shoot proliferation rate (99.75%), shoot number per explant (1.76), shoot length (10.70 cm), leaf number per explants (3.54) after three weeks of culture. In all experiments, no growth was observed for the basal MS medium. Phytohormone combinations of IAA (1.2 mg/L) and kinetin (2.0 mg/L) were found to be the best for shoot proliferation. Among the cultivars, there were significant differences for the highest rooting rate (81.255), root number (2.22), and root length (2.95 cm) variables for Washington Navel. The lowest rooting rate (48.45%), root number (1.47) and root length (2.26 cm) were observed for Valencia. The highest rooting rate (84.90%), root number per microshoot (2.22) and root length (3.05 cm) was on MS medium supplemented with 1.5 mg/L NAA. CONCLUSION: A comparison of different concentrations of IAA and NAA on root induction of microshoots from nodal segments of citrus cultivars demonstrated NAA was a more effective hormone than IAA.

Enzymatic Properties of Red Beet (Beta vulgaris L.) Leaf, Root Pulp, and Peel.

BACKGROUND: Beetroot (Beta vulgaris L.) is botanically classified as a herbaceous biennial belonging to the Chenopodiaceae family and has several varieties with bulb colors ranging from yellow to red. Peroxidases are widely occurring in organisms including microorganisms, plants, and animals, and have been involved in various physiological and biochemical functions. OBJECTIVE: The study was conducted to investigate the characteristics of enzyme extracts from red beet leaves, root pulp, and peel. METHODS: The enzyme extraction involved the homogenization of the sample and filtrate in cold acetone and then the filtrate was homogenized in 0.1M sodium acetate buffer, pH 7. The protein content was determined using the Lowry assay using bovine serum albumin (BSA) as a standard protein. Then, enzymatic activity was determined by peroxidase, polyphenol oxidase, and catalase assays. The patent for biological activity of enzymes was obtained from the Office of Career Development, Haramaya University. The antioxidant activities of the enzyme extract were conducted by using DPPH and hydrogen peroxide free radical scavenging activities. RESULTS: The result indicated that the Enzymatic activity of crude enzyme extract of red beet leaf, root pulp and peel indicated that significantly the highest total soluble protein (16.68 mg/ml), peroxidase activity (PODA, 111.50 U/ml), polyphenol oxidase activity (PPOA, 170.90 U/ml), polyphenol oxidase specific activity (PPOspa, 10.25 U/mg), catalase activity (CATA, 180.50 U/ml) and catalase specific activity (CATspa, 10.82 U/mg), were recorded for red beet leaf enzyme extract. The antioxidant activity of the enzyme extracts demonstrated that significantly higher DPPH radical scavenging activity of leaf extract (59.16) and peel extract (61.92) were recorded. The Pearson correlation coefficient of enzyme activity parameters and free radical scavenging activities presented that protein content was significantly and positively correlated with CATA, PPOA, and PPOspa. Catalase- specific activity (CATspa) was significant and positively correlated only with HPSA. Peroxidase-specific activity (PODspa) was significant and positively correlated with PODA and DPPH. Based on the plot for principal component PC2 vs. PC1 for D statistics DPPH, PODA, and PODspa have close PC1 and PC2 scores (with vector angle < 90° showing similar/correlated effects. CONCLUSION: In this study, B. vulgaris has shown promising peroxidase enzyme activity. Beetroot peel contained higher antioxidant compounds thus promising a more intense utilization of the peels in food and nutraceuticals.

Physicochemical Properties and Biological Activities of Koseret (Lippia adoensis Hochst. Var. Koseret) Seed and Leaf Oil Extracts.

BACKGROUND: Lippia adoensis Hoechst var. adoensis (wild variety) and variety koseret (cultivated variety) have been used as traditional medicine, condiments, and endemic to Ethiopia. OBJECTIVE: This study aimed to assess the physicochemical properties and biological activities of oil extracts from seed and leaves of koseret (L. adoensis var. koseret). METHODOLOGY: Soxhlet apparatus was used for oil extraction using hexane as a solvent. The oil quality assessment was based on oil yield, acid value, percent free fatty acid, and peroxide value, while the biological activities were investigated based on antioxidant and antimicrobial activities. The antimicrobial experiment was arranged as 2 x1x4 in a completely randomized factorial design with three replications. RESULTS: The result indicated that significantly higher oil yield (2.25%), acid value (2.66%) and free fatty acid (1.34%) were recorded for seed oil using the solvent extraction method. Leaf oil was recorded to have significantly higher values of DPPH (2,2- diphenyl-1- picrylhydrazyl), ascorbic acid and total carotenoid contents, but a lower value of hydrogen peroxide scavenging activity indicated that leaf oil presented higher antioxidant activity than seed oil in koseret. The koseret leaf oil demonstrated stronger antibacterial activity with a maximum zone of inhibition (14.50±0.21 mm), minimum inhibitory concentration (MIC, 0.25 µg/ml) and corresponding minimum bactericidal concentration (MBC, 0.25 µg/ml) against S. aureus. Furthermore, leaf oil has also presented stronger antifungal activity with a maximum zone of inhibition (14.83 mm), MIC (0.25 µg/ml), and minimum fungicidal concentration (MFC, 0.50 µg/ml) against Aspergillus versicolor. CONCLUSION: It can be concluded from the results of this study that leaf oil extract has demonstrated better biological activities, including both antioxidant and antimicrobial potentials, than seed oil in koseret.

Physicochemical Properties, Antioxidant and Antimicrobial Activities of Ethiopian Sweet Basil (Ocimum basilicum L.) Leaf and Flower Oil Extracts.

BACKGROUND: The occurrence of multidrug resistant pathogenic microbes has initiated the development of natural antimicrobial agents from plants. Oils from herbal sources have drawn scientific interest due to their potential source of bioactive compounds. OBJECTIVE: This study was aimed to examine the physicochemical and biological activities including antioxidant and antimicrobial potential of the oil extracted from basil leaves and flowers. METHODS: The physicochemical properties of the oil extracts were measured based on oil yield, specific gravity, acid value, free fatty acids and peroxide values whilst the antioxidant activities were assessed by ascorbic acid, DPPH (2, 2- diphenyl-1-picrylhydrazyl), and hydrogen peroxide free radical scavenging activities. The antimicrobial experiment was conducted based on disc diffusion and broth dilution methods. RESULTS: The result of antioxidant activity of Ocimum basilicum indicated significantly higher DPPH (86.45%) for leaf oil extract. The strongest antibacterial activity with maximum zone of inhibition (15.47 mm), minimum inhibitory concentration MIC (0.09 µg/ml), and corresponding minimum bactericidal concentration MBC (0.19 µg/ml) was exhibited by the flower oil extract against Staphylococcus aureus ATCC-25923. The strongest antifungal activity with maximum zone of inhibition (15.90 mm), MIC (0.125 µg/ml, the least value), and minimum fungicidal concentration MFC (0.09 µg/ml) were recorded for leaf oil against Candida albicans. CONCLUSION: It can be concluded from the present study that the sweet basil flower and leaf oil extracts can be potential antioxidant, antibacterial, and antifungal agents.

Physicochemical Properties and Biological Activities of Garlic (Allium sativum L.) Bulb and Leek (Allium ampeloprasum L. var. Porrum) Leaf Oil Extracts.

Allium species including garlic and leek exhibits a broad range of medicinal and nutritional properties. Therefore, this study investigates the physicochemical and biological activities of garlic (Allium sativum L.) and leek (A. ampeloprasum L. var. Porrum) oil extracts. The result indicated that physicochemical properties indicated that significantly higher oil yield (21.25%), ACV (2.66 mg/g), FFA (1.34%), and PV (4.10 meq/kg) and also antioxidant activities with respect to 2, 2-diphenyl-1-picrylhydrazyl, DPPH (27.60 ± 1.55%), hydrogen peroxide (12.35 ± 0.92%) free radical scavenging activities, and ascorbic acid content (25.30 ± 3.25%) were obtained for leek leaf oil extract. Stronger antibacterial activity with a maximum zone of inhibition (16.00 mm), minimum inhibitory concentration (MIC) (0.20 µg/ml), and minimum bactericidal concentration (MBC) (0.40 µg/ml) was recorded for leek oil extract against S. pyogenes. However, garlic oil has presented stronger antifungal activity with a maximum zone of inhibition (13.50 mm), MIC (0.40 µg/ml), and minimum fungicidal concentration (MFC) (0.75 µg/ml) against Candida albicans. It is concluded from the results of this investigation that oils extracts of garlic bulb and leek leaves demonstrated significant biological activities that can be used as sources for pharmaceutical and nutraceutical ingredients.

Physicochemical Properties and Biological Activities of Garden Cress (Lepidium sativum L.) Seed and Leaf Oil Extracts.

Garden cress (Lepidium sativum L.) seed is a rich source of proteins, dietary fiber, omega-3 fatty acids, iron, and other essential nutrients and phytochemicals. The aim of the present study was to investigate the physicochemical properties and biological activities of garden cress (L. sativum) seed and leaf oil extracts using solvent extraction methods. The result indicated that oil yield (25.75 ± 2.48%) and specific gravity (0.84 ± 0.08) were significantly (P < 0.05 based on least significance difference t-test) higher for seed oil extract. Seed oil also presented significantly (P < 0.05) higher antioxidant activities with respect to ascorbic acid content (24.21 ± 3.04%) and DPPH (2, 2-diphenyl-1-picrylhydrazyl) (26.55 ± 0.21%) values. The leaf oil extract has exhibited stronger antibacterial activity with a maximum zone of inhibition (18.50 mm), a minimum inhibitory concentration (MIC) of 0.05 µg/ml, and a minimum bactericidal concentration (MBC) of 0.05 µg/ml against Staphylococcus aureus. Leaf oil extract has also demonstrated stronger antifungal activity with a maximum zone of inhibition (18.50 mm), MIC (0.25 µg/ml), and a minimum fungicidal concentration (MFC) of 0.50 µg/ml against Aspergillus Niger. The result suggesting that leaf oil presented superior antimicrobial but inferior antioxidant potential than seed oil in garden cress.

Molecular mechanisms and biochemical analysis of fluorene degradation by the Pseudomonas sp. SMT-1 strain.

Fluorene is a harmful organic toxicant extensively disseminated in the water and dry land ecosystem. Its toxicity and ubiquitous presence pose issues concerning its biodegradation. Characterization of the molecular mechanisms of fluorene degradation, detection of metabolites, and appraisal of its viability in toxicant removal by the SMT-1 Pseudomonas sp. strain are the main purposes of this study. In this work, the catabolic intermediates were identified from resting cell reactions of the SMT-1 strain as well as the involved catabolic pathway of fluorene. Based on liquid chromatography mass spectrometry analysis, the identified intermediates were 9-fluorenone; 3,4-dihydroxy-9-fluorenone; phthalate and protocatechuic acid. The specific primers were designed to amplify the fluorene-degrading 4921 dioxygenase gene segment from the SMT-1 Pseudomonas sp. strain. The 4921 dioxygenase gene was expressed, purified and characterized. The apparent K m and V max values were 25.99 µM min-1 and 0.77 U mg-1, respectively. The enzyme was most active at pH 7.5 and 25 °C in Tris-HCl buffer and was identified by measuring the initial reaction velocity for 1 min. Effect of metal salts on enzyme activity was accessed to see the impact on protein stability. Most of the analyzed metal salts inhibited enzyme activity to different degrees, and exhibited very low activity in the presence of FeCl3. Understanding the physiological, metabolic pathway and molecular mechanism of fluorene degradation is an important factor in increasing significant information of this biological process. This strain may serve as a potential candidate for further use in the bioremediation process to treat organic toxicant contaminated sites.

Characterization of physico-chemical properties and antioxidant activity of oil from seed, leaf and stem of purslane (Portulaca oleracea L.).

Purslane (Portulaca oleracea L.) is a member of the family of portulacaceae and is a very good source of alpha-linoleic acid. Alpha-linoleic is an omega-3 fatty acid which plays an important role in human growth, development and in preventing diseases. Characterization of the physicochemical properties and antioxidant activity of oil from seeds, leaves and stems of purslane, and appraisal of its viability is the main purpose of this study. In this work, physicochemical properties of oil from seed, leaf and stem of purslane were characterized and the highest oil content was observed in seed (11.25 %) using solvent extraction method. The highest specific gravity was recorded for seed oil (1.10 w/w) followed by leaf oil (0.73 w/w) with non-significant difference. Moreover, oil extracted from purslane stem was found to be the least in oil content (2 %) and specific gravity (0.14 w/w); but the highest in acid value (13.32 w/v) and percentage free fatty acid. The peroxide value was found to be the highest for seed oil and the least for stem with significant difference. The highest ascorbic acid content was recorded for purslane seed oil (41.67 %) followed by leaf oil (32.29 %). Likewise, the highest 1, 1- diphenyl-2-picrylhydrazine activity was obtained for leaf oil (12.55 %) followed by seed oil (2.05 %). The plot for PC2 vs PC1 showed the oil content, specific gravity, peroxide value, ascorbic acid and 1, 1- diphenyl-2-picrylhydrazine having close PC1 and PC2 scores with vector angle < 90 0 showing correlated effects. Characterizing physical and chemical properties and antioxidant activity of oil from seeds, leaves and stems of purslane is crucial in providing necessary information for the utilization of the oil content.

Isolation, Characterization, and Genomic Analysis of Pseudomonas sp. Strain SMT-1, an Efficient Fluorene-Degrading Bacterium.

Comprehensive study of novel microbial organisms capable of degrading fluorene is crucial to develop essential strategies for further application on enhanced bioremediation technologies. Many fluorene-degrading bacteria have been studied; however, little information about the genome sequences of these organisms, which would facilitate investigation of the molecular mechanisms of fluorene degradation, is available. In this study, a bacterial strain designated SMT-1, which uses fluorene as its sole carbon source, was isolated from Laogang landfill in Shanghai, People's Republic of China, and identified as a Pseudomonas sp., based on 16S rRNA gene sequence analysis. Maximum growth and degrading activity of strain SMT-1 were observed at 30°C, pH 7.0 and 200 r/min in mineral salt medium containing 0.4 mm fluorene. We obtained a draft genome sequence of strain SMT-1 to gain insight into the genetic mechanisms for the degradation of aromatic compounds. Sequences greater than 1 kb in length were obtained by Illumina sequencing; strain SMT-1 was found to contain 5542 predicted genes. This working draft genome comprises 68 contigs and DNA scaffolds and has a total size of 6 108 237 bp and a calculated G + C content of 61.59%. Amino acid metabolism clusters were enriched in SMT-1 genes annotation, with the highest abundant observed for the "ABC transporters" subcategories, followed by transcription, energy production and conversion, and inorganic ion transport and metabolism. The genomic information for SMT-1 provides a useful resource for elucidating the molecular mechanism of fluorene catabolism.