Diversity of root associated microorganisms of selected medicinal plants and influence of rhizomicroorganisms on the antimicrobial property of Coriandrum sativum

The total heterotrophic bacteria, actinomycetes and fungus were enumerated from the rhizosphere and non-rhizosphere soil of 50 selected locally available medicinal plants in and around Bharathiar University. In all the plants, population of microorganism were higher in the rhizosphere soil than in the non rhizosphere soil. Among the microorganisms, bacterial population was higher in number followed by fungus and actinomycetes. Of the medicinal plants, the maximum rhizosphere effect was observed in Annona squamosa and the minimum effect was seen in Eclipta alba and Cassia auriculata. Among the bacteria the dominant species was Bacillus followed by Pseudomonas, Enterobacter, Corynebacterium, Micrococcus and Serratia. The Streptomyces species was found to be dominant followed by Deuteromycetes and Frankia among the actinomycetes. Among the fungal isolates Rhizopus was found to be higher in number followed by Aspergillus, Penicillium, Mucor and Fusarium. About 70.96% of the bacterial isolates were found to be nitrate reducers and 90.60% of the bacteria solubilised phosphate. The rhizosphere bacterial isolates were also capable of hydrolyzing starch, cellulose, casein, urea and gelatin. The isolates of bacteria, actinomycetes and fungus were also able to produce phytohormone Indole-3-acetic acid (IAA). The maximum IAA production was recorded by Fusarium sp (5.8 mg/l). The rhizosphere bacterial isolates showed resistance to 14 commercially used antibiotics. In an attempt to check the influence of these plant growth promoting microorganisms on the antimicrobial property of Coriandrum sativum against Escherichia coli MTCC-443 and Aeromonas hydrophila MTCC-646, the results observed was not encouraging since the inoculants did not influence the antibacterial property. However extensive and in depth study is required to find out the influence of rhizomicroorganisms on the antibacterial property of medicinal plants. The other results clearly indicated that the rhizosphere microorganisms could be exploited for its innumerable properties and active metabolites.     

The subtidal pump: a mechanism of interstitial water exchange by wave action

Sandy subtidal sediments are part of the earth's largest filter system. Water flow through bottom sediments is driven by wave action on the sea surface. The mechanisms involved are described, including a theoretical deduction and field measurements. As an example, the total water exchange through part of the West Atlantic shelf is computed and the influence of the phenomenon is discussed from a biological point of view and with regard to its importance for the world's oceans.     

Mass-transfer processes of chromium(VI) adsorption onto guava seeds

The chromium(VI) biosorption onto guava seeds, as an alternative method for Cr⁶⁺ removal from aqueous solutions, was investigated. The parameters affecting kinetics and equilibrium of Cr⁶⁺ adsorption onto guava seeds were studied. An external mass-transfer diffusion coefficient k and intra-particle diffusion coefficient k_i were determined to measure the rate-limiting step of adsorption. A single external mass-transfer diffusion model and intra-particle diffusion models were used. The effects of initial pH, sorbent mass, and initial Cr⁶⁺ concentrations on mass-transfer coefficients were investigated. The external mass-transfer coefficient has an average value of 7.2×10^-3 cm s^-1, while the intra-particle mass-transfer diffusion coefficient was 0.34 mg g^-1 min^-0.5. This indicates that external diffusion to the guava seeds surface and intra-particle diffusion are both involved in the sorption process. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models with an average correlation coefficient R²=0.98. The maximum removal of Cr⁶⁺ was obtained at pH 1 (about 100% for adsorbent dose of 15 g l^-1 and 25 mg l^-1 initial concentration of Cr⁶⁺). The results indicated that the guava seeds exhibit acceptable sorption capacity.     

部分菊科入侵种种子(瘦果)的萌发能力和幼苗建群特性

对入侵种种子生物学各方面的了解有助于更好地预测入侵趋势和评估可持续管理的策略.研究通过对部分菊科入侵种种子(瘦果)进行的室内萌发实验和土壤埋藏实验,通过与相关研究的对比和分析,对这些入侵种的萌发能力和幼苗建群特性进行了研究.10个入侵种种子室内萌发实验的结果表明,在25℃、12h光照的情况下,除钻形紫菀和一年蓬以外,被研究的其它8个种的终萌发率超过了50%,而且都显示出早期快速萌发的特点.用SPSS的曲线拟合工具对10个种的累积萌发趋势进行了曲线回归分析,对应的最佳模型均为三次曲线方程.不同土壤埋藏深度下幼苗出苗实验的结果表明,菊科8个入侵种的种子在表土的出苗率均最高,随着覆土厚度的增加,种子的出苗率逐渐降低,当覆土厚度超过3 cm以上时,所有种子均不能出苗.种子在不同的埋藏深度的出苗情况与种子的大小有关,较大种子破土能力相对较强;种子在不同的埋藏深度的出苗情况与种子本身的萌发能力也相关.土壤埋藏期限的实验结果表明,随埋藏时期的增加,小蓬草、苏门白酒草和一年蓬3个人侵种种子的活力逐步降低,在土壤中埋藏12个月后,其活力分别为21.34%、18.15%和27.38%.这些入侵种较广的种子萌发温度适应范围和高萌发率为防除工作带来了困难.在生产上,可通过不同时期的翻耕、将种子深埋等措施减少这些入侵种的危害.     

Direct, residual and direct + residual effects of sulphur in garlic (Allium sativum)-maize (Zea mays) cropping sequence

Significant positive effects of 30 kg/ha of sulphur as manifested on yield and yield parameters of garlic were further carried over to following maize crop. Garlic bulb and foliage yield (6.3 and 0.8 t/ha respectively) obtained at 30 kg/ha of sulphur dose was significantly higher over without sulphur (3.7 and 0.5 t/ha respectively) as revealed from two years' pooled data. Similarly number of leaves/plant, weight of cloves/5bulbs and weight/100 cloves at the said sulphur dose significantly increased over without sulphur from 10.5 to 11.9, 98.3 to 141.2 g and from 159 to 217 g in respective manner Increase in grain yield of maize (residual effect) and in the economic yield of the whole cropping sequence (Bulb yield of garlic and grain yield of maize) i.e. direct plus residual effect at 30 kg/ha of sulphur dose over without sulphur was from 28.3 to 47.2 and from 71 to 116 q/ha in respective manner i.e. with significant differences. Sulphur use efficiencies (kg yield/kg sulphur) of these crops at 15, 30 and 45 kg/ha over no sulphur were 57, 43 and 32; 53, 63 and 6 and 160, 150 and 67, all in respective order An optimum sulphur dose of 44.3 kg/ha produced increased bulb yield (over no S) worth Rs 34892 over fertilizer cost giving B:C ratio of 31.5:1. Utilization of sulphur added at 15, 30 and 45 kg/ha rates was 24.1, 19.3 and 15.7% by the garlic crop; and 29.6. 24.5 and 9.02% by the following maize crop, thus, adding up to 54.1, 43.8 and 24.9% by the cropping sequence, all in respective order.     

The toxic effect of CuO of different dispersion degrees on the structure and ultrastructure of spring barley cells (Hordeum sativum distichum)

Environmental Geochemistry and Health - Nowadays, nanotechnology is one of the most dynamically developing and most promising technologies. However, the safety issues of using metal nanoparticles,...     

铝对豌豆根边缘细胞存活率和粘胶层厚度的影响

根边缘细胞（Root border cells）是从根冠游离并聚集在根尖周围的一群特殊细胞，铝毒的作用部位正是根尖，因此推测边缘细胞在铝毒反应中起着重要作用。作者研究了不同铝浓度（0、50、100、250、500μmol／L AlCl3（含0．1mmol／L CaCl2，pH4．5）与离体豌豆（Pisum Sativum）根边缘细胞共培养1h、2h、4h、6h、8h、24h后根边缘细胞存活率、粘胶层厚度及细胞数量的变化，以揭示铝毒胁迫边缘细胞的响应。结果为：随着处理时间的延长，边缘细胞的存活率明艰下降；在0～100μmol／L铝浓度范围，边缘细胞存活率有随铝浓度升高而降低的趋势；8h及24h边缘细胞存活率为铝浓度500μmol／L时显著高于0、50、100和250μmol／L时，6h边缘细胞存活率为250和500μmol／L铝浓度时显著高于0、50、100μmol／L AlCl3时。随处理时间延长，边缘细胞数量降低，铝浓度100，250和500μmol／L时边缘细胞数量低于0和50μmol／L时，且铝浓度越高，细胞数量越少；随处卵时间延长和铝浓度升高，粘胶层相对面积增加，铝浓度500和250μmol／L时粘胶层相对面积增加尤为明湿。通过与pH7．01水溶液及pH4．50水溶液中粘胶层变化的比较，发现粘胶层在铝处理8h后出现一个峰值，可能是粘胶物质的诱导合成和分泌。研究结果表明，铝毒对根边缘细胞具有致死效应，这种致死效应在一定浓度范围符合剂量依数性关系，高浓度时则边缘细胞存活率反而升高，这与根边缘细胞对铝毒作出的适应性响应——粘胶层的增厚和细胞降解增强有关。粘胶层起着保护和减轻边缘细胞铝毒的作用。     

Hood construction as a spacing mechanism inCleistostoma kuwaitense (Crustacea: Ocypodidae)

The ocypodid crabCleistostoma kuwaitense inhabits the upper shores of the mudflats of Kuwait, where it constructs a semi-permanent mud hood over the entrance to its burrow. Between September and November 1986, data were collected on the distribution and orientation of the hoods and their openings to investigate the crab's social spacing system. Irrespective of density, the distribution of burrow hoods is non-random, tending towards a regular dispersion. A contributory factor for this dispersion pattern is that the surface hoods tend to increase the distance between adjacent burrows. The hood openings are randomly distributed with respect to compass direction but avoid directly facing those of nearest neighbours. In the absence of burrow plugging and eviction as used by other ocypodid crabs, construction of elongated hoods appears to be a good alternative for ensuring social spacing.     

全氟辛酸和全氟辛基磺酸的光降解技术及机理研究进展

目前,普遍存在于各种环境介质中的全氟辛酸(PFOA)和全氟辛基磺酸(PFOS)造成的环境污染问题已引起全球的广泛关注.PFOA和PFOS具有稳定性、持久性和生物累积性等特点.常规的方法如:超声降解法、电化学氧化法和微生物降解法等,很难将其彻底降解,因此开发有效的PFOA和PFOS降解技术成为了环境领域的研究重点.近年来...     

Ameliorated effects of garlic (Allium sativum) on biomarkers of subchronic acrylamide hepatotoxicity and brain toxicity in rats

Acrylamide (ACR) exerts its toxicity through stimulation of the oxidative stress; yet, its effect on neurotransmitter catabolic enzymes has not been elucidated. We investigated the effects of ACR exposure on brain and hepatic tissues antioxidant enzymes activities and different markers such as, acetylcholinesterase (AChE), nitric oxide (NO), monoamine oxidase (MAO), and lipid profile, and to evaluate the protective effects of garlic against ACR toxicity. Male Sprague-Dawley rats were exposed to ACR (1 mg kg^?1 body weight) with or without diet containing 1.5% of garlic powder for 40 days. ACR administration showed a decrease in AChE activity associated with an increase in MAO activity in both brain and hepatic tissues. In addition, ACR administration increased the lipid peroxidation and NO levels of both tissues while decreased the activities of glutathione (GSH), superoxide dismutase, and glutathione-S-transferase (GST). On the other hand, the activities of glutathione peroxidase (GPx) and catalase activities increased as a consequence of GSH depletion after ACR exposure. Finally, ACR exposure increased the brain and liver lipid profile of cholesterol, triglycerides and total lipid, while phospholipids level was decreased. Coadministration of garlic powder with ACR significantly attenuated oxidative stress, MAO activity, and inflammation in brain and hepatic tissues but did not ameliorate AChE activity. In conclusion, our results emphasized the role of garlic as a potential adjuvant therapy to prevent ACR neurotoxicity and hepatotoxicity.     

Ackee apple (Blighia sapida) seeds: a novel adsorbent for the removal of Congo Red dye from aqueous solutions

The ability of ackee apple (AA) seeds to remove Congo Red (CR) dye from aqueous solution was investigated. AA was characterised using thermo gravimetric analyser, scanning electron microscopy, Braunauer Emmett Teller, pH_pzc, elemental analysis and Boehm titration. The effects of operational parameters such as adsorbent dosage, contact time, initial dye concentration and solution pH were studied in a batch system. pH has a profound influence on the adsorption process. Maximum dye adsorption was observed at pH 3.0. The reaction was fast, reaching equilibrium in 90 min. Adsorption data were best described by Langmuir isotherm and the pseudo-second-order kinetic model with a maximum monolayer coverage of 161.89 mg·g^?1. Both boundary layer and intraparticle diffusion mechanisms were found to govern the adsorption process. Thermodynamic parameters such as standard free energy change (Δ G ⁰), standard enthalpy change (Δ H ⁰), and standard entropy change (Δ S ⁰) were studied. Values of Δ G ⁰ varied between?30.94 and?36.56 kJ·mol^?1, Δ H ⁰ was 25.61 kJ·mol^?1, and Δ S ⁰ was 74.84 kJ·mol^?1·K^?1, indicating that the removal of CR from aqueous solution by AA was spontaneous and endothermic in nature. Regeneration and reusability studies were carried out using different eluents. AA gave the highest adsorption efficiency up to four cycles when treated with 0.3 M HCl. AA was found to be an effective adsorbent for the removal of CR dye from aqueous solution.     

Acute toxicity and histopathology study of a galactose-specific lectin from the seeds of Tetracarpidium conophorum (African walnut) (Hutch and Dalz)

A lactose-binding lectin (TCL) was purified from the seeds of African walnut, Tetracarpidium conophorum, and acute toxicity studies of the lectin were carried out with Swiss albino male mice. Animals were administered doses of TCL from 500 to 2500?mg?kg^?1 body weight (b.wt.) orally while intraperitoneally the dose ranged from 10 to 600?mg?kg^?1 b.wt. Animals were then assessed for organ and body weight changes, mortality, and histopathology. TCL did not cause any observable toxicity via the oral route; however, when administered intraperitoneally, TCL elicited toxicity with an LD₅₀ of 50?mg?kg^?1 b.wt. Death from intoxication was preceded by convulsion, hypoactivity, salivation, ataxia, and weakness. The animals given lethal doses of the lectin showed profound respiratory depression which was judged to be the primary cause of death. Histopathological analysis indicated that the lungs, liver, and spleen were adversely affected while the kidney and other organs were essentially normal. In all the affected organs, the severity of toxicity was dose-dependent as the effect of the lectin became more pronounced with increase of the dose administered.     

The impact of flooding on property prices: A repeat-sales approach

In this paper we use a repeat-sales model to analyse the price path of properties affected by flooding in England between 1995 and 2014. Our dataset contains information on 4.8 million houses with at least one repeat-sale. This database is merged with high-definition GIS data delineating the spatial extent of all recorded flood incidents in England covering a total area of 2,654 km². Our results show that immediately after a flood event the price of property in a postcode entirely inundated by inland flooding is on average 24.9% lower than non-flooded property, whereas for property in a postcode entirely inundated by coastal flooding the price reduction is 21.1%. Nonetheless, we find that this discount is short-lived and the discount is no longer statistically significant for properties affected by inland flooding after 5 years, which falls to just 4 years for properties affected by coastal flooding. For lower-priced properties however, the post-flood price discount can be observed up to 6–7 years for both inland and coastal flooding. The magnitude of the impact also depends on the characteristics of the properties, the characteristics of the flood and the existence of flood protection assets.     

Spray mechanism of crepidogastrine bombardier beetles (Carabidae; Crepidogastrini)

Summary.   The defensive glandular apparatus of primitive bombardier beetles of the tribe Crepidogastrini (Carabidae) is described for the first time. As exemplified by two African species (Crepidogaster ambreana and C. atrata), the apparatus conforms to the basic bombardier plan, in that the glands are bicompartmented and the secretion is quinonoid (it contains 1,4-benzoquinones and hydrocarbons), hot, and discharged audibly. In a number of morphological respects the crepidogastrine apparatus resembles that of the classical bombardiers of the tribe Brachinini (rather than that of bombardiers of the paussoid lineage), reinforcing the view, already held on taxonomic grounds, that the Crepidogastrini and Brachinini are closely related. That the Crepidogastrini may be primitive relative to Brachinini is underscored by the finding that, unlike brachinines, crepidogastrines do not pulse their secretory emissions. Moreover, they discharge their secretion as a mist, rather than forcibly in the form of jets. Received 22 May 2001; accepted 29 May 2001.     

Wave action: the environmental trigger for hatching in the California grunion Leuresthes tenuis (Teleostei: Atherinopsidae)

 California grunion Leuresthes tenuis (Teleostei: Atherinopsidae) emerge from the ocean to spawn on beaches of southern California. Grunion eggs do not hatch at a set developmental age, but remain in the sand until turbulent surf at high tide washes them out to sea. In previously studied fishes and amphibians that lay eggs terrestrially, low oxygen is the trigger for hatching in water, and high oxygen tensions inhibit hatching. For the grunion, however, eggs placed in air, seawater and oil did not hatch at any at oxygen tension until they were agitated in fluid. Following agitation in seawater, all eggs hatched within several minutes. Grunion eggs in normoxic or hyperoxic water hatched significantly faster than eggs agitated at the lowest oxygen tensions. Mechanical agitation, not hypoxia, is the environmental trigger for hatching in California grunion eggs. Received: 15 May 1999 / Accepted: 5 April 2000     

Virus-like particles in Heterosigma akashiwo (Raphidophyceae): a possible red tide disintegration mechanism

Electron microscopical observations on algal samples collected in 1992 in the middle or final stages of a red tide in Hiroshima Bay, Japan, revealed virus-like particles (VLPs) in the red tide alga Heterosigma akashiwo (Class Raphidophyceae). The host cells appeared moribund and the VLPs were located in and around the nuclear area. The VLPs were icosahedral, ca. 185 nm in diameter, and generated from the periphery of several viroplasms. VLPs were also observed in three other types of H. akashiwo-like cells, which were morphologically distinguishable from each other. The appearance of VLPs in the red tide alga could explain the dramatically rapid termination of this red tide.     

“Glandular pockets” of the integument and feeding mechanism inPagurus bernhardus (Crustacea: Anomura)

The benthic anomuran crabPagurus bernhardus (L) were collected from the North Sea near Helgoland, West Germany, during the years 1986–1987. The histological study of the integument ofPagurus bernhardus reveals a double structure with dorsal and ventral cuticular layers and with two epithelial cell layers. Additional structures have been developed within the integument to trap micro food organisms. The structure and function of the cupshaped glandular pockets of the integument is described. The cells which secrete mucus are also described. Histological and histochemical methods have been employed to study the chemical nature of various cells of the integument and the secretions of the glandular pockets. The ecological significance of the sensory hairs, glandular pockets, cuticular layers and the supra-branchial groove is discussed with reference to the crab's feeding mechanism.     

Biosorption of Cr（VI） by carbonized Eupatorium adenophorum and Buckwheat straw： thermodynamics and mechanism

High quality and low cost carbon can be prepared from Eupatorium adenophorum （E. adenophorum） and Buckwheat straw. The biosorbent was used for Cr（VI） removal. The effect of experimental parameters, such as pH, sorbent dosage and temperature were examined and the optimal experimental condition was determned. Solution pH is found influencing the adsorp- tion. Cr（VI） removal efficiency is found to be maximum （98%） at pH= 1. Langmuir and Freundlich adsorption isotherms were applicable to the adsorption process and their constants were evaluated. The adsorption data obtained agreed well with the Langmuir sorption isotherm model. The maximum adsorption capacities for Cr（VI） ranged from 46.23 to 55.19mg.g^-1 for temperature between 298 K and 308 K under the condition of pH = 1.0. Thermodynamic parameters such as free energy change （AG）, enthalpy （AH） and entropy （AS） indicate a spontaneous, endothermic and increased randomness nature of Cr（VI） adsorption. Studies found that the raw E. adenophorum and buckwheat straw mixed materials with simple treatment had a high efficiency for the removal of Cr（VI） and would be a promising adsorbent.