Improved production of biosurfactant by a <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> mutant using vegetable oil refinery wastes

Biosurfactant production by Pseudomonas aeruginosa EBN-8 mutant was studied in shake flasks on separate wastes from canola, soybean and corn oil refineries. Of the substrates tested, canola oil refinery waste (COD=20 g l⁻¹) supplemented with sodium nitrate (at COD/N=20) showed the best microbial growth (4.50 g l⁻¹) and rhamnolipid production (8.50 g l⁻¹), at 10 d of incubation with the specific growth rate of 0.316 h⁻¹ and specific product yield of 0.597 g g⁻¹ h. Its cell-free supernatant showed the critical micelle dilution (CMD) of 150 and surface tension (ST) of 28.5 mN m⁻¹.     

Description and SEM Observations of Meloidogyne sasseri n. sp. (Nematoda: Meloidogynidae), Parasitizing Beachgrasses

Meloidogyne sasseri n. sp. is described and illustrated from American beachgrass (Ammophila breviliffulata) originally collected from Henlopen State Park and Fenwick Island near the Maryland state line in Delaware, United States (6). Its relationship to M. graminis, M. spartinae, and M. californiensis is discussed. Primary distinctive characters of the female perineal pattern were a high to rounded arch with shoulders, widely spaced lateral lines interrupting transverse striations, a sunken vulva and anus, and coarse broken striae around the anal area. Second-stage juvenile body length was 554 μm (470-550), stylet length 14 μm (13-14.5), tail length 93 μm (83-115), tapering to a finely rounded terminus. Male stylet length 20 μm (19-21.5), spicule length 33 μm (30-36). Scanning electron microscope observations provided additional details of perineal patterns and face views of the female, male, and J2 head. Wheat, rice, oat, Ammophila sp., Panicum sp., bermudagrass, zoysiagrass and St. Augustinegrass were tested as hosts. Distribution of the species was the coasts of Delaware and Maryland. The common name "beachgrass root-knot" is proposed for M. sasseri n. sp.     

Sugar beet extract acts as a natural bio-stimulant for physio-biochemical attributes in water stressed wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

The present study investigated the role of sugar beet extract (SBE) as a bio-stimulant to ameliorate the adverse effects of drought on seed germination and growth of wheat (Triticum aestivum L.). Different concentrations of SBE (0, 10, 20, 30, 40 and 50%) were used for priming the wheat seeds. The experiment was conducted in laboratory (PEG-8000 was used to create water stress) as well as under natural environmental conditions (using soil with 100 and 60% field capacity). Significant ameliorating effects of seed priming with SBE were recorded on different germination attributes, i.e., time to 50% emergence (E₅₀), germination index (GI), mean emergence time (MET), germination percentage (G%), coefficient of uniformity of emergence (CUE) and germination energy (GE) under water stress. Without priming, the plants exhibited symptoms of water stress like decreased biomass, reduction in photosynthetic pigments, e.g., chlorophyll, carotenoids. Seed pre-conditioning with SBE improved the plant growth, photosynthetic pigments, antioxidants’ activities and nutrient homeostasis of plants facing water deficit and grown under well-watered conditions. The maximum increase in biomass, content of chlorophyll, carotenoids and activities of superoxide dismutase (SOD) and peroxidase (POD) was 13.4, 8.5, 11.9, 7.6, 13.6, 42.0, 19.8%, respectively, with SBE seed priming under water stress. In conclusion, SBE seed priming effectively reduced the negativities of water stress on seed germination which resulted in better plant growth in terms of enhanced biomass, photosynthetic pigments, antioxidant defense mechanism and better nutrient homeostasis. Overall, the findings suggest that seed pre-conditioning with SBE as a bio-stimulant will be helpful for better crop stand establishment under low field capacity, especially in semi-arid and arid agricultural fields.     

Primary structure of the hemoglobin α-chain of rose-ringed parakeet (Psittacula krameri)

The structure of the hernoglobin α-chain of Rose-ringed Parakeet was determined by sequence degradations of the intact subunit, the CNBr fragments, and peptides obtained by digestion with staphylococcal Glu-specific protease and trypsin. Using this analysis, the complete α-chain structure of 21 avian species is known, permitting comparisons of the protein structure and of avian relationships. The structure exhibits differences from previously established avian α-chains at a total of 61 positions, five of which have residues unique to those of the parakeet (Ser-12, Gly-65, Ser-67, Ala-121, and Leu-134). The analysis defines hemoglobin variation within an additional avian order (Psittaciformes), demonstrates distant patterns for evaluation of relationships within other avian orders, and lends support to taxonomic conclusions from molecular data.     

Gibberellins and indole-3-acetic acid producing rhizospheric bacterium Leifsonia xyli SE134 mitigates the adverse effects of copper-mediated stress on tomato

Beneficial bacteria Supplemental data for this article can be accessed at https://doi.org/10.1080/17429145.2017.1370142.View all notesliving in the rhizosphere pose several implications on plant growth promotion and are highly desirable for sustainable agriculture. In the current study, we explored the ameliorative capacity of Leifsonia xyli SE134, a plant growth-promoting rhizobacteria (PGPR), against copper (Cu) stress on tomato grown under elevated Cu levels of 50 and 100?mM. Initially, L. xyli SE134 modulated innate gibberellins (GAs) and indole-3-acetic acid (IAA) metabolism in response to elevated Cu toxicity. The IAA contents increased, whereas that of bioactive GAs decreased in relation to Cu concentration gradient in the broth media. Furthermore, exposure to elevated Cu caused detrimental effects on the physiological attributes as revealed by attenuated shoot length, root length, stem diameter, shoot dry weight, root dry weight, and chlorophyll content in non-inoculated tomatoes as compared to L. xyli SE134 inoculated plants. The growth rescuing effect of L. xyli SE134 may be attributed to the modulation of endogenous amino acids contents in plants, such as glutamic acid, threonine, phenylalanine, glycine, proline, and arginine. Moreover, L. xyli SE134 inoculation stimulated total polyphenol and flavonoid content, reduced super oxide dismutase activity, strongly inhibited Cu, and increased phosphorus and iron content in plants grown under elevated Cu stress. In the absence of Cu toxicity, L. xyli SE134 significantly enhanced amino acid content, improved total flavonoids, and increased phosphorus content, thus resulting in higher plant growth.     

Secondary metabolism of pharmaceuticals in the plant in vitro cultures: strategies,approaches, and limitations to achieving higher yield

Biotechnology is playing a vital alternative role in the production of pharmaceutical plant secondary metabolites to support industrial production and mitigate over-exploitation of natural sources. High-value pharmaceuticals that include alkaloids, flavonoids, terpenes, steroids, among others, are biosynthesized as a defensive strategy by plants in response to perturbations under natural environmental conditions. However, they can also be produced using plant cell, tissue, and organ culture techniques through the application of various in vitro approaches and strategies. In the past decades, efforts were on the clonal propagation, biomass and secondary metabolites production in the in vitro cultures of medicinally important plants that produce these molecules. In recent years, the effort has shifted towards optimizing culture conditions for their production through the application of cell line selection, elicitation, precursor feeding, two-phase co-culture among cell, tissue, and organ culture approaches. The efforts are made with the possibility to scale-up the production, meet pharmaceutical industry demand and conserve natural sources of the molecules. Applications of metabolic engineering and production from endophytes are also getting increasing attention but, the approaches are far from practical application in their industrial production.