Extraction and characterization of essential oil components based on geraniol and citronellol from Java citronella (Cymbopogon winterianus Jowitt)

Citronella oil is the main product of Java citronella grass (Cymbopogon winterianus Jowitt) rich in geraniol and citronellol, widely used in mosquito repellents and perfumeries. The age of the plant plays a key role in oil composition and its yield such that young leaves have lesser oil content than the mature leaves. Also, a remarkable difference between fresh and dried leaves regarding oil yield is observed. The various methods of extracting essential oils from citronella grass with respect to yield (%) were studied. Average percent yield in the manual extraction and hydro-distillation procedure was 0.8 and 1 % respectively, which was better as compared to steam distilled oil (0.7 %). The chromatographic analysis of essential oils with respect to standards geraniol and citronellol were studied by high performance thin layer chromatography (HPTLC) with n-hexane and ethyl acetate (3:2) as mobile phase followed by its separation on plates. The developed plates showed geraniol, citronellol and citronellal as major bands. The analysis of all extracted oil samples by means of electrospray ionization-mass spectrometry (ESI-MS) in the positive ion mode showed rapid mass fingerprints of constituents present in the samples according to the observed mass of standards. Furthermore, the analysis of vibrational spectra was accomplished with Fourier transform infra-red spectroscopy (FTIR) specifying all the functional groups as major peaks confirming all of them as monoterpene alcohols with conjugated double bonds. Thus, HPTLC, ESI-MS and FTIR studies evidenced that the two essential oil components were majorly present in the methanol extract suggesting methanol as a good extractant in the manual extraction process.     

生草栽培对山核桃林地土壤养分及微生物多样性的影响

高强度经营导致山核桃林地土壤性质改变,设置了白三叶、黑麦草、油菜、紫云英、自然杂草和清耕(对照)6个处理,以3次重复,随机排列的2年田间试验,研究了不同生草栽培对山核桃林地土壤养分和微生物多样性的影响。结果表明:与清耕相比,生草栽培均能改善土壤养分状况,除全钾外,白三叶和紫云英处理较其他处理能显著提高土壤养分含量,其余几个处理间差异不明显;生草栽培显著提高了土壤微生物生物量碳(MBC)含量,白三叶、黑麦草、紫云英、油菜和自然杂草处理分别较清耕提高了169.6%、159.7%、144.1%、138.6%和58.6%,差异达显著水平(P0.05)。6种不同处理的土壤微生物活性(AWCD)、微生物Shannon指数和均匀度指数均存在明显差异。不同处理的土壤AWCD为白三叶紫云英油菜自然杂草黑麦草清耕;白三叶处理的土壤微生物Shannon指数高于其他处理;白三叶、紫云英和油菜处理的土壤微生物均匀度指数显著高于其他处理。相关性分析表明,土壤微生物活性、微生物Shannon指数和均匀度指数两两之间均达到极显著差异(P0.01),三者与土壤各养分指标之间未达显著差异,但表现为正相关关系。白三叶、紫云英和油菜对改善土壤微生物特性效果较好。     

Constituents of marsh grass: Survey of the essential oils in Juncus roemerianus

The essential oil of Juncus roemerianus was isolated by steam distillation with a yield of 0·01 % of the fresh grass. Analysis by combined GLC-MS gave evidence for the presence of 78 compounds. They included 13 benzene derivatives, 11 polycyclic (mostly naphthalene type) compounds, 8 cyclohexyl compounds, 32 acyclic compounds, 9 terpenoids, and 6 furan derivatives. In total, these compounds accounted for 46·6% of the oil. Due to the presence of tetrachlorobenzene and benzyl cyanide, other halogenated compounds and alkaloids can be anticipated.     

Variation in levels of lipid components and protein in ecogeographic races of Sorghum bicolor

Sorghum bicolor (L.) Moench is a widespread grass of the African savanna. It contains wild and cultivated subspecies which have morphologically distinct ecogeographic races. Measurements of the amount of oil and protein in sorghum grains revealed significant differences in protein levels between wild and cultivated subspecies. Measurements of the relative percentages of fatty acid components of oil also revealed significant differences in levels of oleic and linoleic acid among wild and cultivated races. We conclude that morphological differences acquired in the course of differentiation of ecogeographic races have been paralleled by differentiation in levels of lipid components and grain protein levels.     

Inhibitory effect of lemongrass oil and its major constituents on Candida biofilm and germ tube formation

Adhesion to a variety of host cells and the surface of biomaterials is a critical step in successful colonization and infection by Candida spp. Several essential oils are known to possess antifungal properties and are potentially used as antifungal agents. By studying the efficacy of essential oils against different pathogenic fungi in the genus Candida, we have evaluated the in vitro antifungal effects of eight essential oils used in aromatherapy, namely holy basil (Ocimum sactum L), lemongrass (Cymbopogon citratus DC), citronella grass (Cymbopogon winterianus Jowitt), kaffir lime (Citrus hystrix DC), sweet basil (Ocimum basilicum Linn), Plai (Zingiber cassumunar Roxb), Curcuma (Curcuma longa Linn), and ginger (Zingiber officinale Rose), against Candida albicans and Candida krusei in both planktonic and biofilm form. The results revealed that among the tested essential oils, lemongrass oil exhibited the most effective killing activity and possessed the strongest inhibitory effect on Candida biofilm formation. In addition, lemongrass oil and its major constituents can inhibit germ tube formation, which might affect adherence. The data in this study indicates that lemongrass oil possessed antibiofilm activity and could modulate candidal colonization. Therefore, it is a promising essential oil to combat candidal colonization and infection.     

饲料氧化鱼油对草鱼肝胰脏结构和功能的损伤

为了探讨饲料氧化鱼油对草鱼(Ctenopharyngodon idellus)肝胰脏组织结构及其功能的影响, 研究以豆油、鱼油及氧化鱼油作为饲料脂肪源, 分别设计鱼油组(6F)、豆油组(6S)、2%氧化鱼油(4S2OF)、4%氧化鱼油(2S4OF)及6%氧化鱼油(6OF)5组等氮、等能的半纯化饲料, 在池塘网箱中养殖72d。结果显示: 氧化鱼油显著增加草鱼血清ALB、GLB、MDA和GSH含量(P0.05), 显著降低肝胰脏GSH和SOD含量(P0.05); 氧化鱼油会显著增加草鱼肝胰脏指数及肝胰脏脂肪含量(P0.05), 且草鱼血清TG含量显著上升(P0.05), HDL/LDL显著下降(P0.05); 氧化鱼油使血清及肝胰脏TC含量显著增加(P0.05), 血清TBA显著下降(P0.05), 肝胰脏TBA显著上升(P0.05); 氧化鱼油会引起草鱼脂肪肝, 损伤肝胰脏细胞线粒体, 并导致肝胰脏细胞纤维化和组织萎缩。结果表明: 饲料添加氧化鱼油会引起草鱼氧化应激, 并降低草鱼肝胰脏抗氧化能力; 扰乱草鱼肝胰脏脂肪代谢, 引起脂肪肝; 影响胆汁酸肝肠循环, 使胆汁酸在肝胰脏中堆积, 并损伤肝胰脏细胞线粒体, 最终增加草鱼肝胰脏脂肪性肝炎发生率。     

Quantifying Microbial Utilization of Petroleum Hydrocarbons in Salt Marsh Sediments by Using the 13C Content of Bacterial rRNA

Natural remediation of oil spills is catalyzed by complex microbial consortia. Here we took a whole-community approach to investigate bacterial incorporation of petroleum hydrocarbons from a simulated oil spill. We utilized the natural difference in carbon isotopic abundance between a salt marsh ecosystem supported by the ¹³C-enriched C₄ grass Spartina alterniflora and ¹³C-depleted petroleum to monitor changes in the ¹³C content of biomass. Magnetic bead capture methods for selective recovery of bacterial RNA were used to monitor the ¹³C content of bacterial biomass during a 2-week experiment. The data show that by the end of the experiment, up to 26% of bacterial biomass was derived from consumption of the freshly spilled oil. The results contrast with the inertness of a nearby relict spill, which occurred in 1969 in West Falmouth, MA. Sequences of 16S rRNA genes from our experimental samples also were consistent with previous reports suggesting the importance of Gamma- and Deltaproteobacteria and Firmicutes in the remineralization of hydrocarbons. The magnetic bead capture approach makes it possible to quantify uptake of petroleum hydrocarbons by microbes in situ. Although employed here at the domain level, RNA capture procedures can be highly specific. The same strategy could be used with genus-level specificity, something which is not currently possible using the ¹³C content of biomarker lipids.     

Effects of Essential Oils on Ruminal Microorganisms and Their Protein Metabolism

A commercial blend of essential oil (EO) compounds was added to a grass, maize silage, and concentrate diet fed to dairy cattle in order to determine their influence on protein metabolism by ruminal microorganisms. EO inhibited (P < 0.05) the rate of deamination of amino acids. Pure-culture studies indicated that the species most sensitive to EO were ammonia-hyperproducing bacteria and anaerobic fungi.     

Bioremediation of volatile oil hydrocarbons by epiphytic bacteria associated with American grass (Cynodon sp.) and broad bean (Vicia faba) leaves

Fresh leaves of American grass and broad beans grown in pristine soil were naturally colonized with cultivable volatile oil hydrocarbon-utilizing bacteria, whose numbers increased significantly in plants grown in oily soil. According to their 16S rRNA gene sequences those bacteria were affiliated to various species of the genera Rhodococcus and Pseudomonas. Qualitative growth studies revealed that pure cultures of these phyllospheric bacteria could grow successfully on a solid mineral medium containing individual alkanes with chain lengths of C₉ through C₄₀ and the aromatics phenanthrene, naphthalene, and biphenyl as sole sources of carbon and energy. Quantitative measurements showed that the individual pure bacterial isolates degraded between about 20 and 30% of crude oil, n-hexadecane, or phenanthrene in batch culture after a one-week incubation. These results reflect the high hydrocarbon degradation potential of those bacteria. The isolates were diazotrophic (nitrogen fixers), meaning that they were self-dependent in covering their nitrogen requirements. Incubating fresh leaves in closed microcosms containing volatile oil hydrocarbons resulted in up to more than 80% attenuation of these compounds after two weeks. Experimental evidence was provided that the leaf tissues did not contribute to this attenuation, which was exclusively due to the bacterial activity.     

Effects of Heterogeneous Competitor Distribution and Ramet Aggregation on the Growth and Size Structure of a Clonal Plant

Spatially heterogeneous distribution of interspecific competitors and intraspecific aggregation of offspring ramets may affect the growth and size structure of clonal plant populations, but these have been rarely studied. We conducted a greenhouse experiment in which we grew a population of eight offspring ramets (plants) of the stoloniferous clonal plant Hydrocotyle vulgaris aggregately or segregately in two homogeneous treatments with or without a competing grass Festuca elata and a heterogeneous treatment with a patchy distribution of the grass. In patchy grass treatments, H. vulgaris produced markedly more biomass, ramets and stolons in open patches (without grasses) than in grass patches, but displayed lower size variations as measured by coefficient of variation of biomass, ramets and stolons among the eight plants. In open areas, H. vulgaris produced statistically the same amounts of biomass and even more stolons and showed higher size variations in patchy grass treatments than in open (no grass) treatments. In grass areas, H. vulgaris grew much worse and displayed higher size variations in patchy grass treatments than in full grass treatments. Ramet aggregation decreased the growth of H. vulgaris in open treatments and in both open and grass patches in patchy grass treatments, but had little effect in full grass treatments. Ramet aggregation had little effect on size variations. Therefore, heterogeneous distribution of competitors can affect the growth and size structure of clonal plant populations, and ramet aggregation may decrease population growth when they grow in open environments or heterogeneous environments with a patchy distribution of interspecific competitors.     

Degradation of Bermuda and Orchard Grass by Species of Ruminal Bacteria

Fiber degradation in Bermuda grass and orchard grass was evaluated gravimetrically and by scanning and transmission electron microscopy after incubation with pure cultures of rumen bacteria. Lachnospira multiparus D-32 was unable to degrade plant cell wall components. Butyrivibrio fibrisolvens 49 degraded 6 and 14.9% of the fiber components in Bermuda grass and orchard grass, respectively, and Ruminococcus albus 7 degraded 11.4% orchard grass fiber but none in Bermuda grass. Both B. fibrisolvens and R. albus lacked capsules, did not adhere to fiber, and degraded only portions of the more easily available plant cell walls. R. flavefaciens FD-1 was the most active fiber digester, degrading 8.2 and 55.3% of Bermuda and orchard grass fiber, respectively. The microbe had a distinct capsule and adhered to fiber, especially that which is slowly degraded, but was able to cause erosion and disorganization of the more easily digested cell walls, apparently by extracellular enzymes. Results indicated that more digestible cell walls could be partially degraded by enzymes disassociated from cellulolytic and noncellulolytic bacteria, and data were consistent with the hypothesis that the more slowly degraded plant walls required attachment. Microbial species as well as the cell wall architecture influenced the physical association with and digestion of plant fiber.     

Sox genes in grass carp (Ctenopharyngodon idella) with their implications for genome duplication and evolution

The Sox gene family is found in a broad range of animal taxa and encodes important gene regulatory proteins involved in a variety of developmental processes. We have obtained clones representing the HMG boxes of twelve Sox genes from grass carp (Ctenopharyngodon idella), one of the four major domestic carps in China. The cloned Sox genes belong to group B1, B2 and C. Our analyses show that whereas the human genome contains a single copy of Sox4, Sox11 and Sox14, each of these genes has two co-orthologs in grass carp, and the duplication of Sox4 and Sox11 occurred before the divergence of grass carp and zebrafish, which support the "fish-specific whole-genome duplication" theory. An estimation for the origin of grass carp based on the molecular clock using Sox1, Sox3 and Sox11 genes as markers indicates that grass carp (subfamily Leuciscinae) and zebrafish (subfamily Danioninae) diverged approximately 60 million years ago. The potential uses of Sox genes as markers in revealing the evolutionary history of grass carp are discussed.     

Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize

The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.     

Content of microelements in the grass shrimp pandalus kessleri (Decapoda: Pandalidae) from coastal waters of the Lesser Kurilskaya Ridge

The concentrations of Fe, Zn, Cu, Cd, Mn, Pb, and Ni were determined in the hepatopancreas, muscle tissue, and carapace of the grass shrimp Pandalus kessleri from the coastal waters of the Lesser Kurilskaya Ridge. Sex reversal of the grass shrimp, which is a proterandrous hermaphrodite, had a marked influence on the concentrations of such metals as Fe, Cu, Cd, and Mn. The levels of Cd in the hepatopancreas of grass shrimp exceeded maximum permissible concentrations for seafood at all the stations studied. The main factors determining the metal levels in P. kessleri from the investigated locations are discussed.     

Dietary lipid requirement on non-specific immune responses in juvenile grass carp (Ctenopharyngodon idella)

This study aimed to evaluate the dietary lipid requirement and its effects on liver oxidative status and non-specific immune responses of juvenile grass carp (Ctenopharyngodon idella). Purified diets with five dietary lipid levels (0%, 2.5%, 5%, 7.5% and 10%, fish oil/corn oil = 1:1) were each fed to triplicate groups of grass carp (mean initial weight: 6.57 ± 0.01 g) in a recirculating rearing system maintained at 27.5 ± 0.5 °C for 10 weeks. Percent weight gain was highest (P < 0.05) with 5% lipid and lowest in fish fed the lipid free control diet. Feed efficiency (FE) and protein efficiency ratio (PER) in fish followed the same pattern of percent weight gain. Fish fed with lipid containing diets had better non-specific immune response indexes (e.g. phagocytic activity, plasma peroxidase and lysozyme activity) and low-level of liver oxidation status than fish fed with the control diet. But excess dietary lipid supplement would bring over metabolic burden to liver. After the feeding trial, fish were challenged by Aeromonas hydrophila. Fish fed control diet obtained significantly (P < 0.05) lower survival rate. The survival rate was highest with 7.5% lipid. The results of this study indicated that proper dietary lipid supplementation enhanced the immune response of grass carp and improved the survival rate in the bacterial challenge, but excess dietary lipid may elevate liver oxidation rates of grass carp. Analysis by second-order regression of percent weight gain indicated that the optimal dietary lipid level in juvenile grass carp (6.6–35.5 g) is about 6.5%.     

The Effects of Seed Ingestion by Livestock,Dung Fertilization,Trampling, Grass Competition and Fire on Seedling Establishment of Two Woody Plant Species

The increasing rate of woody plant encroachment in grasslands or savannas remains a challenge to livestock farmers. The causes and control measures of woody plant encroachment are of common interest, especially where it negatively affects the objectives of an agricultural enterprise. The objectives of this study were to determine the effects of gut passage (goats, cattle), dung (nutrients), fire, grass competition and trampling on establishment of A. nilotica and D. cinerea seedlings. Germination trials were subjected to the following treatments: 1) seed passage through the gut of cattle and goats and unpassed/ untreated seeds (i.e. not ingested), 2) dung and control (no dung), 3) grass and control (mowed grass), 4) fire and control (no fire), 5) trampling and control (no trampling). The interaction of animal species, grass and fire had an effect on seedling recruitment (P < 0.0052). Seeds retrieved from goats and planted with no grass and with fire (6.81% ± 0.33) had a significant effect on seedling recruitment than seeds retrieved from goats and planted with grass and no fire (2.98% ± 0.33). Significantly more D. cinerea and A. nilotica seeds germinated following seed ingestion by goats (3.59% ± 0.16) than cattle (1.93% ± 0.09) and control or untreated seeds (1.69% ± 0.11). Less dense grass cover, which resulted in reduced grass competition with tree seedlings for light, space and water, and improved seed scarification due to gut passage were vital for emergence and recruitment of Acacia seedlings. These results will contribute considerably to the understanding of the recruitment phase of woody plant encroachment.     

Natural attenuation of weathered oil using aquatic plants in a farm in Southeast Mexico

An experiment was conducted in field for three years to assess the sustainability of aquatic plants Leersia hexandra, Cyperus articulatus, and Eleocharis palustris for use in the removal of total hydrocarbons of weathered oil in four areas contaminated with 60916–119373 mg/kg of hydrocarbons. The variables evaluated were coverage of plant, dry matter, density of plant growth-promoting rhizobacteria, and the removal of total weathered oil. The variables showed statistical differences (p = 0.05) due to the effects of time and the amount of oil in the soil. The three aquatic plants survived on the farm during the 36-month evaluation. The grass L. hexandra yielded the greatest coverage of plant but was inhibited by the toxicity of the oil, which, in contrast, stimulated the coverage of C. articulatus. The rhizosphere of L. hexandra in control soil was more densely colonized by N-fixing bacteria, while the density of phosphate and potassium solubilizing rhizobacteria was stimulated by exposure to oil. C. articulatus coverage showed positive relationship with the removal of weathered oil; positive effect between rhizosphere and L. hexandra grass coverage was also identified. These results contributed to the removal of weathered oil in Gleysols flooded and affected by chronic discharges of crude oil.     

Reproductive morphology of the early-divergent grass Streptochaeta and its bearing on the homologies of the grass spikelet

Reproductive morphology and development are described in the Brazilian grass Streptochaeta spicata, in order to assess the homologies of the characteristic grass inflorescence, termed a spikelet, and other reproductive organs. Streptochaeta possesses some features that are commonly found in Poaceae, including a well-differentiated embryo. It also possesses some relatively unusual, presumably derived features, such as non-plumose stigmas, which indicate that it could be insect-pollinated. It shares some features with other early-divergent grasses, such as Pharus, which could represent plesiomorphic conditions for grasses. The inflorescence unit in Streptochaeta has been interpreted as a compound branching system or pseudospikelet. The present data suggest that it is a highly modified spikelet, with a modified flower borne either on a different axis to the basal bracts (glumes) or on the same axis as the basal bracts. The three bracts below the stamens are interpreted as homologous to the lodicules. The Streptochaeta spikelet could be considered as morphologically intermediate between the true spikelet of grasses and reproductive units of close grass relatives.     

Vegetable oil replacements for petroleum oil adjuvants in Herbicide sprays

The objectives of this research were to observe plant response to vegetable oil sprays and to learn if vegetable oils — sunflower, soybean, linseed, or camelina — can replace petroleum oil as an herbicide adjuvant. Vegetable oils were sprayed on grain sorghum [Sorghum bicolor (L.) Moench.] and sunflower (Helianthus annuus L.) at 4 7 L/ha and were neither harmful nor beneficial to the crops. When used as an adjuvant postemergence with 1.68 kg/ha of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], 2.3 L/ha of vegetable oil were as effective in weed control as either 2.3 or 9.4 L/ha of petroleum oil. All atrazine treatments gave complete control of dicotyledonous weeds. But vegetable oil adjuvants with atrazine at 1.68 kg/ha gave significantly more grass weed control than atrazine alone at 2.24 kg/ha in two of five trials and were equally good in the other trials. The cost of the adjuvant is less than that of the atrazine replaced, and the initial herbicide residue in the soil is reduced by 25%.     

Myrmecotopical transformation of grass stand structure on a plot of fragmented forest

The authors have ecologically and cenotically characterized the grass stand around anthills of Formica polyctena Foerst. on a plot of fragmented forest and have determined species composition of myrmecotopic grass assembly. The study revealed prairification and synanthropization of the grass stand as well as similarity of cenotic and morphologic changes in grass covers around anthills of F. aquilonia Yarr. and F. polyctena.