Spraying bananas in Fiji to control black leaf streak disease

Three sprays, maneb in water applied by hydraulic knapsack sprayer and maneb in an oil/water emulsion or an oil/water emulsion alone applied by mistblower were compared for the control of black leaf streak disease of banana caused by Mycosphaerella sp.
Although there were no differences in yield in the 'plant' crop, maneb, especially as a water-based spray, resulted in much better disease control and leaf survival. Oil seemed to have an adverse effect on fruit quality but not on plant growth.
Since it is unlikely that oil alone will adequately control the disease in ratoon crops fungicides may be necessary.     

Movements of myelin sheath particles in a weak electric field

When a weak electric field is applied to longitudinal sections of myelinated nerve, myelin material migrates out of the tissue edges towards both poles. the materials migrating from the anodal and cathodal edges seem to be chemically similar but differ in physical properties. at the anodal edge the bimolecular lipid layers rearrange into spherical micelles forming an “oil in water” emulsion, and at the cathodal edge into micelles forming a “water in oil” emulsion. the latter is unstable in water and is rapidly transformed into an “oil in water” emulsion. these findings have physiological and structural implications for the study of biological membranes.     

The Potential of Stagonospora sp. as a Mycoherbicide for Field Bindweed

Field bindweed ( Convolvulus arvensis L.) is one of the 12 most important weeds worldwide. Stagonospora sp. Isolate LA39 was isolated from diseased field bindweed plants collected in Europe. No crop tested was susceptible to the fungus, but disease symptoms were observed on other Convolvulaceae species. On field bindweed, the fungus induces disease symptoms (i.e. lesions) mainly on leaves and less severely on stems. The application of spores in an oil emulsion (10% oil in water) enhanced the disease on field bindweed plants compared with spores suspended in a 0.1% aqueous solution of the surfactant agent, Tween 80. The necrotic leaf area of inoculated plants increased as the length of exposure to 100% relative humidity (RH) and the spore density applied increased. Severe disease developed on plants inoculated with 1 107 spores/ml in oil emulsion, even in the absence of exposure to 100% RH. A delay of exposure to 100% RH (up to 8 h) did not have a significant eVect on disease severity. Field bindweed was susceptible to the fungus at all growth stages tested, but older plants were more susceptible than younger ones. It was concluded that isolate LA39 has potential as a biocontrol agent of field bindweed, especially when applied in an oil emulsion. The oil emulsion maintains the aggressiveness of the pathogen during a dew-free period and provides a favourable microenvironment during the infection process.     

Effect of Oil Content and Composition on the Gelling Properties of Egg-SPI Proteins Stabilized Emulsion Gels

Effects of different oils on the rheological properties, textural profile, water loss (WL), oil loss (OL) and microstructure of egg-soybean protein isolate (SPI) stabilized emulsion gels were investigated at neutral pH, wherein soybean oil, olive oil and menhaden oil were used to form emulsions. The results showed that viscosity of emulsions progressively increased with the increase of oil content. Similarly, analysis of the rheological behavior of the formulated emulsion gels revealed an increase in the mechanical strength (G’) with the increase in oil concentration, indicating that oil droplets played a significant role in the formation of the gel structure. In addition, at high levels of oil, the hardness and chewiness of emulsion gels were also high, while a slight decrease in springiness and cohesiveness were observed. A linear relationship between hardness and water/oil loss was found, whereas the Pearson correlation suggested that less drainage of water may slow down the outflow of oil. The microstructural images showed a more compact network as a result of the increase of oil content in the formulation. Scarce significant differences were found among emulsion gels formulated with different oil type, suggesting oil composition played a dispensable role on the gelling properties of emulsion gels.

     

The Effect of Post Inoculation Treatment with Mineral Oil on TMV Multiplication in Tobacco Leaves and Protoplasts

Half leaves of N. tabacum dipped into a 0.2 % emulsion of meneral oil 15min after inoculation with tabacco masaic virus (TMV) developed significantly fewer lesion than when not dipped Dipping reduced lesion numbers when applied up to 2½ h after inoculation and multiple dippings were more effective than one. The effect of oil was the same whether the inoculum was whole virus or RNA. Tobacco protoplasts treated with mineral oil contained less virus than untreated protoplasts. The oil probably acted by killing the protoplasts and was effective only when protoplasts were centrifuged through the oil emulsion, When water-treated leaves were dipped into a TMV solution there was an effect on TMV infection similar to that caused by dipping in oil after TMV inoculation.     

Application of polyhydroxyalkanoate binding protein PhaP as a bio-surfactant

PhaP or phasin is an amphiphilic protein located on surfaces of microbial storage polyhydroxyalkanoates granules. This study aimed to explore amphiphilic properties of PhaP for possible application as a protein surfactant. Following agents were used to conduct this study as controls including bovine serum albumin, sodium dodecyl sulfate (SDS), Tween 20, sodium oleate, a commercial liquefied detergent together with the same amount of PhaP. Among all these tested control surfactants, PhaP showed the strongest effect to form emulsions with lubricating oil, diesel, and soybean oil, respectively. PhaP emulsion stability study compared with SDS revealed that PhaP had a stronger capability to maintain a very stable emulsion layer after 30 days while SDS lost half and two-thirds of its capacity after 2 and 30 days, respectively. When PhaP was more than 200 μg/ml in the water, all liquids started to exhibit stable emulsion layers. Similar to SDS, PhaP significantly reduced the water contact angles of water on a hydrophobic film of biaxially oriented polypropylene. PhaP was thermally very stable, it showed ability to form emulsion and to bind to the surface of polyhydroxybutyrate nanoparticles after a 60- min heating process at 95 °C. It is therefore concluded that PhaP is a protein with thermally stable property for application as natural and environmentally friendly surfactant for food, cosmetic, and pharmaceutical usages.     

Adjuvants enhance the biological control potential of an isolate of Colletotrichum gloeosporioides for biological control of sicklepod (Senna obtusifolia)

In greenhouse experiments, unrefined corn oil, Silwet L-77, and an invert emulsion were tested as adjuvants with the mycoherbicidal fungus Colletotrichum gloeosporioides, a weakly virulent pathogen of sicklepod (Senna obtusifolia). A 1:1 (v/v) fungus/corn oil tank mixture containing 0.2% (v/v) Silwet L-77 surfactant reduced the dew period requirements for maximum weed infection and mortality from 16 to 8 h, and delayed the need for free moisture for greater than 48 h. This formulation also resulted in the ability of the pathogen to infect and kill weeds in larger (>5 leaf) growth stages. The invert emulsion resulted in similar effects upon these parameters. These results suggest that invert emulsions, unrefined corn oil and Silwet L-77 surfactant greatly improve the bioherbicidal potential of this pathogen for control of sicklepod, a serious weed pest in the southeastern US.     

Stem vascular architecture in the rattan palm Calamus (Arecaceae-Calamoideae-Calaminae)

Climbing stems in the rattan genus Calamus can reach lengths of well over 100 m, are long-lived, and yet their vascular tissue is entirely primary. Such a combination suggests that stem vasculature is efficient and resistant to hydraulic disruption. By means of an optical shuttle and video recording of sequential images we analyzed the stem of a cultivated species. The stem has vascular features that are unusual compared with those in arborescent palms and seemingly inefficient in terms of long-distance water transport. Axial bundles are discontinuous basally because leaf traces, when followed downwards, always end blindly below. Furthermore, there is no regular distal branching of each leaf trace at its level of departure into a leaf, so that neither a continuing axial bundle nor bridges to adjacent axial bundles are produced as in the standard palm construction. Instead, the axial bundles in the stem periphery are connected to leaf traces and to each other by narrow and irregular transverse or oblique commissures that are not the developmental homologues of bridges. As in other palms, metaxylem within a leaf trace is not continuous into the leaf so that the only connection to a leaf is via protoxylem. Within the stem, protoxylem (tracheids) and metaxylem (vessels) are never contiguous, unlike in other palms, which suggests that water can only move from metaxylem to protoxylem, and hence into the leaf, across a hydraulic resistance. We suggest that this minimizes cavitation of vessels and/or may be associated with an unknown mechanism that refills embolized vessels. Also, the metaxylem can be significant in stem water storage in the absence of abundant ground parenchyma.     

Effects of Lecithin Addition in Oil or Water Phase on the Stability of Emulsions Made with Whey Proteins

The effects of lecithin addition in oil or water phase on the stability of oil-in-water emulsions made with 0.1 wt% whey protein and 10 wt% n-tetradecane at neutral and acidic pH were studied by monitoring the gravitational creaming and phase separation. The effects of lecithin addition on the interfacial behavior of β-lactoglobulin were also studied to compare with the results of emulsion stability. At neutral pH, crude phosphatidylcholine (PC) from egg yolk or soybean increased the stability of the emulsion made with protein and lowered the interfacial tension of protein films more effectively than pure egg PC. A more remarkable effect on both the emulsion stability and the interfacial tension was found when crude PC was added in the oil phase rather than in the water phase. The purity of lecithins and the way to add them are suggested to be very important to make a stable emulsion with protein. On acidic pH (4.5 or 3.0), the increased creaming or phase separation in a whey protein-stabilized emulsion, but the lowered interfacial tension of β-lactoglobulin films, were found upon the addition of pure or crude PC in oil or water phase. These results suggest that in acidic pH, densely packed films may be formed on a planar oil–water interface, but not on adsorbed layers around oil droplets in an emulsion.     

Water potential increase in sliced leaf tissue as a cause of error in vapor phase determinations of water potential

Earlier reports that the water potential of sliced leaf tissue is higher than that of unsliced control tissue are confirmed. The effect is shown to increase as damage to the tissue due to slicing is increased. However, there is some evidence that increase in damage beyond a certain point causes water potentials to fall again towards the control value. The electrical resistance of washings from sliced leaf tissue increases with increase in the time interval between slicing and washing. Both the rise in water potential of sliced tissue and the rise in electrical resistance of washings are partially and reversibly inhibited by low temperature. These results suggest that the remaining intact cells actively accumulate solutes released from the cells cut open on slicing. The sap from the sliced cells is thereby diluted and flows passively into the intact cells. Since pressure potential changes more rapidly with cell volume than does osmotic potential, the net result is a rise in the total water potential of sliced tissue. It is concluded that this effect may cause spuriously high water potential values to be measured if excessively small pieces of leaf tissue are used. This is demonstrated with stacks of annuli cut from leaves.     

Degradation of crude oil in the rhizosphere of Sorghum bicolor

Dissipation of petroleum contaminants in the rhizosphere is likely the result of enhanced microbial degradation. Plant roots may encourage rhizosphere microbial activity through exudation of nutrients and by providing channels for increased water flow and gas diffusion. Phytoremediation of crude oil in soil was examined in this study using carefully selected plant species monitored over specific plant growth stages. Four sorghum (Sorghum bicolor L.) genotypes with differing root characteristics and levels of exudation were established in a sandy loam soil contaminated with 2700 mg crude oil/kg soil. Soils were sampled at three stages of plant growth: five leaf, flowering, and maturity. All vegetated treatments were associated with higher remediation efficiency, resulting in significantly lower total petroleum hydrocarbon concentrations than unvegetated controls. A relationship between root exudation and bioremediation efficiency was not apparent for these genotypes, although the presence of all sorghum genotypes resulted in significant removal of crude oil from the impacted soil.     

Enhancement of the antimicrobial properties of bacteriophage‐K via stabilization using oil‐in‐water nano‐emulsions

Bacteriophage therapy is a promising new treatment that may help overcome the threat posed by antibiotic‐resistant pathogenic bacteria, which are increasingly identified in hospitalized patients. The development of biocompatible and sustainable vehicles for incorporation of viable bacterial viruses into a wound dressing is a promising alternative. This article evaluates the antimicrobial efficacy of Bacteriophage K against Staphylococcus aureus over time, when stabilized and delivered via an oil‐in‐water nano‐emulsion. Nano‐emulsions were formulated via thermal phase inversion emulsification, and then bacterial growth was challenged with either native emulsion, or emulsion combined with Bacteriophage K. Bacteriophage infectivity, and the influence of storage time of the preparation, were assessed by turbidity measurements of bacterial samples. Newly prepared Bacteriophage K/nano‐emulsion formulations have greater antimicrobial activity than freely suspended bacteriophage. The phage‐loaded emulsions caused rapid and complete bacterial death of three different strains of S. aureus. The same effect was observed for preparations that were either stored at room temperature (18–20°C), or chilled at 4°C, for up to 10 days of storage. A response surface design of experiments was used to gain insight on the relative effects of the emulsion formulation on bacterial growth and phage lytic activity. More diluted emulsions had a less significant effect on bacterial growth, and diluted bacteriophage‐emulsion preparations yielded greater antibacterial activity. The enhancement of bacteriophage activity when delivered via nano‐emulsions is yet to be reported. This prompts further investigation into the use of these formulations for the development of novel anti‐microbial wound management strategies. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:932–944, 2014     

Superheated water extraction of essential oils from Cinnamomum zeylanicum (L.)

Introduction – Superheated water extraction (SHWE) potentially provides an environmentally friendly and clean extraction technique which uses a minimum or no organic solvent. The scope and limitations of the technique have still to be fully explored. Objective – To investigate the application of SHWE to cinnamon (Cinnamomum zeylanicum L.) bark and leaves as typical plant materials to determine if this extraction method can yield a higher quality oil. Methodology – Samples of cinnamon bark or leaves were extracted at 200°C with water under pressure. The essential oils were obtained from the aqueous solution using a solid phase extraction cartridge and were then examined by GC‐MS. Results – Using superheated water extraction, cinnamon bark oil with over 80% cinnamaldehyde and cinnamon leaf oil containing up to 98% eugenol were obtained. Alternative solvent extraction methods were also studied but led to emulsion formation apparently because of the presence of cellulose breakdown products. Conclusion – Superheated water extraction offers a cheap, environmentally friendly technique with a shorter extraction time than hydrodistillation and yielded a higher quality oil with a higher proportion of eugenol than hydrodistillation. Copyright © 2010 John Wiley & Sons, Ltd.     

Recent advances in petroleum microbiology.

Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times (<60 s) are being used effectively. Microbes are being injected into partially spent petroleum reservoirs to enhance oil recovery. However, these microbial processes have not exhibited consistent and effective performance, primarily because of our inability to control conditions in the subsurface environment. Microbes may be exploited to break stable oilfield emulsions to produce pipeline quality oil. There is interest in replacing physical oil desulfurization processes with biodesulfurization methods through promotion of selective sulfur removal without degradation of associated carbon moieties. However, since microbes require an environment containing some water, a two-phase oil-water system must be established to optimize contact between the microbes and the hydrocarbon, and such an emulsion is not easily created with viscous crude oil. This challenge may be circumvented by application of the technology to more refined gasoline and diesel substrates, where aqueous-hydrocarbon emulsions are more easily generated. Molecular approaches are being used to broaden the substrate specificity and increase the rates and extents of desulfurization. Bacterial processes are being commercialized for removal of H(2)S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments.     

Mobility and enhanced biodegradation of a dilute waste oil emulsion during land treatment

Summary The mobility and biodegradability in soil of a dilute waste oil emulsion generated by an aluminium rolling industry was investigated. Laboratory simulations and field evaluation of waste disposal suggested that the majority of the oil emulsion was retained in surface soil following application. However, potential leaching of waste to the subsurface was demonstrated, particularly at higher loading rates in soils of sandy texture. Strategies to enhance rates of biodegradation in surface soils were investigated, including fertilization and microbial inoculation. A single strain inoculum was obtained from a group of 81 isolates selected for their ability to partially mineralize the waste oil emulsion, and was tentatively characterized as a hydrocarbonoclasticCorynebacterium sp. Inoculation did not effectively stimulate waste removal in soil compared with fertilization, which significantly increased respiration and biodegradation. The maximum loss of the applied oil emulsion from soil was 30% during a 56-day in vitro incubation. Fertilized, aerated liquid waste emulsion was more rapidly degraded, resulting in loss of 65% of the waste emulsion within 18 days.Published with the approval of the Director of the West Virginia University Agriculture and Forestry Experiment Station as Scientific Article no. 2324.     

Biodegradable PLGA microcarriers for injectable delivery of chondrocytes: effect of surface modification on cell attachment and function

Poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were prepared by an oil/water emulsion solvent evaporation method to use as an injectable microcarrier for cell delivery. Three different kinds of PLGA microspheres having hydrophobic, negatively charged, and positively charged surfaces were prepared. Hydrophobic and negatively charged PLGA microspheres were prepared by using terminally capped and uncapped PLGA polymer, respectively. Positively charged PLGA microspheres were prepared by blending PLGA with PLGA-g-poly(L-lysine) graft copolymer as a surface modifying agent. Bovine chondrocytes were cultured on the three PLGA microspheres under serum conditions to comparatively evaluate cell attachment, cell proliferation, and cell function with respect to surface properties. Positively charged PLGA microspheres showed the highest cell attachment, growth, and function compared to hydrophobic and negatively charged microspheres. Surface-modified PLGA microspheres can potentially be used as an injectable delivery system for cells into a tissue defect site.     

三元(碱-表面活性剂-聚合物)复合驱油藏采出水微生物群落特征

与水驱技术相比,向油藏中注入碱、表面活性剂和聚合物(简称三元复合驱,ASP)能大幅提高石油采收率,但这些驱油剂对油藏中微生物多样性与群落结构的影响尚亟待阐明,这对油田水质管理与腐蚀控制均具有的重要意义. 本研究采用高通量测序技术解析了大庆油田ASP油藏4口油井采出水中的微生物多样性与群落结构. 结果表明: ASP油藏采出水的pH高达9.65. 采出水中微生物Shannon多样性指数为2.00～3.56,采出井间菌群多样性存在差异. 在门、纲、属分类水平上,变形菌门(85.5%～98.3%)、γ-变形菌纲(83.7%～97.8%)、栖碱菌属(51.8%～82.5%)是绝对优势菌群. 共检测到12个属的潜在硫化氢产生菌,以硫磺单胞菌属丰度最高(0.4%～7.4%). 与已发表的水驱油藏研究结果相比,三元复合驱油藏采出水微生物群落组成独特,呈嗜/耐碱趋势,其多样性偏低,群落结构更单一.     

Effects of mycorrhizal infection on drought tolerance and recovery in safflower and wheat

The influence of arbuscular mycorrhizal fungi on drought tolerance and recovery was studied in safflower (Carthamus tinctorius L.) and wheat (Triticum aestivum L.). Plants were grown with and without the mycorrhizal fungus, Glomus etunicatum Becker & Gerd., in nutrient-amended soil under environmentally-controlled conditions to yield mycorrhizal and nonmycorrhizal with similar leaf areas, root length densities, dry weights, and adequate tissue phosphorus. When drought stress was induced, mycorrhizal infection did not affect changes in leaf water, osmotic or pressure potentials, or osmotic potentials of leaf tissue rehydrated to full turgor in either safflower or wheat. Furthermore, in safflower, infection had little effect on drought tolerance as indicated by the level of leaf necrosis. Mycorrhizal wheat plants, however, had less necrotic leaf tissue than uninfected plants at moderate levels of drought stress (but not at severe levels) probably due to enhanced phosphorus nutrition. To determine the effects of infection on drought recovery, plants were rewatered at a range of soil water potentials from –1 to –4 MPa. We found that although safflower tended to recover more slowly from drought after rewatering than wheat, mycorrhizal infection did not directly affect drought recovery in either plant species. Daily water use after rewatering was reduced and was correlated to the extent that leaves were damaged by drought stress in both plant species, but was not directly influenced by the mycorrhizal status of the plants.     

干姜挥发油纳米乳的制备与表征

为提高干姜挥发油的水溶性及在制剂过程中的稳定性,尝试将干姜挥发油制备成纳米乳载药形式,并对其进行表征。本文将提取的干姜挥发油进行成分分析并测定HLB值,通过处方筛选确定乳剂配比,并对所得干姜挥发油纳米乳的类型、粒径分布、表面电位及稳定性进行表征。经实验测得干姜中含挥发油2.1%,为淡黄色或黄色液体,HLB值为8,以吐温-80和司盘-80为表面活性剂,乳剂的最佳体积配比为油∶乳化剂∶水=6∶1∶13,激光粒度仪测得平均粒径为41.4 nm,表面电位为-10.31±1.51 mv,离心稳定常数为21.83%。此方法所得干姜挥发油纳米乳稳定性好,在水中分散性能好、稳定,可有效减少挥发油的损失。     

A Vapour-pressure Instrument for the Measurement of Leaf and Soil Water Potential

A previously described vapour-pressure osmometer has been adaptedfor the measurement of depression of water potential (DPD) insamples of leaf tissue and soil. A pile of about 30 leaf annuliare contained in an air-tight metal capsule through the lidof which passes a pipette. A drop of water hangs from the tipof the pipette into the central cavity of the pile of leaf annuli.The drop is drawn bath into the pipette from time to time andthe rate of evaporation from it measured directly. The water-potentialdepression is linearly related to the rate of evaporation. Theinstrument is calibrated empincally. A period of a hours isnecessary to attain vapour equilibnum before readings are takenThe readings then occupy less than 30 minutes. For the calibration data, using filter paper moistened withNaCl solution, the 5 percent inverse tolerance limits for singlereadings of water-potential depression were ±0.26 atm.With leaf material the errors appear to be about the same, althoughrelease of cell sap at the cut edges of the disks may causean overestimation by as much as 0.5 atm. with turgid leaf material.Lining the capsule with leaf strips gave erroneous results.Using a suitably modified capsule the instrument can be usedfor soil-water potential measurement. Equilibration takes only30 minutes so that a reading can be completed within an hour.