Evaluation of Petrifilm™ EC method for enumeration of E. coli from soil

Aims: To evaluate the suitability of commercially available Petrifilm? EC plates for enumeration of Escherichia coli from soil. Methods and Results: A confirmed E. coli strain isolated from liquid swine manure was inoculated into sterilized sandy clay loam and loam soils at the concentrations of 10², 10³, 10⁵ CFU g^?1 of soil. The efficiency of recovery on Petrifilm? EC plates for soils spiked with E. coli was compared with standard membrane filtration techniques on m‐FC basal medium supplemented with 3‐bromo‐4‐chloro‐5‐indoyl‐β‐d ‐glucopyranoside (BCIG) and most probable numbers (MPN) techniques in E. coli medium with 4‐methylumbelliferyl‐β‐d ‐glucuronide (EC‐MUG) broth. Petrifilm? EC and m‐FC (BCIG) methods were then assessed for the ability to recover E. coli from field soils applied with swine manure. No significant differences (P > 0·05) were observed between Petrifilm? EC, m‐FC (BCIG) and MPN methods for the recovery of E. coli from spiked samples, irrespective of soil type. However, recovery of E. coli from manure‐applied field soil samples showed a significant difference (P < 0·05) between the Petrifilm? EC method and the m‐FC method in enumerating E. coli possibly as a result of false positives on m‐FC. Conclusion: The Petrifilm? EC method is suitable for the enumeration of E. coli from soil with a detection limit of 10 CFU g^?1 soil. Significance and Impact of the Study: The commercially available Petrifilm? EC method is comparatively low cost, easy to use method for the enumeration of E. coli from soil without the need for further confirmation tests.     

Cortical cell death, cell proliferation, macromolecular movements and rTip1 expression pattern in roots of rice (Oryza sativa L.) under NaCl stress

The mode of action of NaCl in terms of cell proliferation and cell death was examined in seminal roots of rice plants (Oryza sativa L.). Salt/sodium chloride was inhibitory to cell number increase and to cell death in cortical tissue, whereas final cortical cell size was the same as in control roots that were not exposed to NaCl. It seems that NaCl may stimulate the transition phase from cell division to cell elongation. Further analysis of the role of NaCl in the suppression of cortical cell death was confined to a delay in the early stage of cell collapse, which was caused by tonoplast disruption, and plasma-membrane destruction. Sodium chloride did not have any effect on the cell-to-cell movement of macromolecules in the root cortex. In-situ hybridization studies indicated that expression of the gene for tonoplast intrinsic protein (rTip1) was localized predominantly in the epidermal and exodermal cells as well as in metaxylem cells in seminal roots. Upon NaCl treatment, the intensity of rTip1 gene expression was raised in the cortical parenchyma, suggesting that salt plays a role in the rapid onset of cell elongation. Received: 2 April 1998 / Accepted: 18 September 1998     

Enemy release or invasional meltdown? Deer preference for exotic and native trees on Isla Victoria,Argentina

Abstract How interactions between exotic species affect invasion impact is a fundamental issue on both theoretical and applied grounds. Exotics can facilitate establishment and invasion of other exotics (invasional meltdown) or they can restrict them by re‐establishing natural population control (as predicted by the enemy‐release hypothesis). We studied forest invasion on an Argentinean island where 43 species of Pinaceae, including 60% of the world's recorded invasive Pinaceae, were introduced c. 1920 but where few species are colonizing pristine areas. In this area two species of Palearctic deer, natural enemies of most Pinaceae, were introduced 80 years ago. Expecting deer to help to control the exotics, we conducted a cafeteria experiment to assess deer preferences among the two dominant native species (a conifer, Austrocedrus chilensis, and a broadleaf, Nothofagus dombeyi) and two widely introduced exotic tree species (Pseudotsuga menziesii and Pinus ponderosa). Deer browsed much more intensively on native species than on exotic conifers, in terms of number of individuals attacked and degree of browsing. Deer preference for natives could potentially facilitate invasion by exotic pines. However, we hypothesize that the low rates of invasion currently observed can result at least partly from high densities of exotic deer, which, despite their preference for natives, can prevent establishment of both native and exotic trees. Other factors, not mutually exclusive, could produce the observed pattern. Our results underscore the difficulty of predicting how one introduced species will effect impact of another one.     

aAd-p53基因靶向治疗癌性胸腹水的临床效果分析

目的:探讨aAd-p53注射液靶向灌注治疗癌性胸腹水的临床疗效和安全性。方法:选择2012年5月-2014年2月在我院接受治疗的癌性胸腹水患者80例,根据治疗方法的不同,将患者随机分为研究组和对照组,每组40例。研究组患者采用腔内灌注rAd-p53治疗,对照组患者采用表阿霉素灌注治疗,观察并比较两组患者的治疗总有效率、不良反应的发生率及KPS功能评分的变化情况。结果:所有患者均顺利完成灌注治疗,病情获得好转,生存质量得到改善。研究组和对照组的治疗总有效率分别为70%、67.5%,两组比较无显著性差异(P0.05)。两组治疗后KPS评分均显著高于治疗前,且研究组高于对照组,差异具有统计学意义(P0.05)。研究组和对照组不良反应的发生率分别为20%和25%,研究组低于对照组,但两组差异并无统计学意义(P0.05)。结论:rAd-p53注射液靶向灌注治疗是一种治疗癌性胸腹水安全有效的方法,值得临床推广。     

春尺蠖蛹雌雄外部形态特征快速鉴别分析

为依据春尺蠖Apocheima cinerarius Erschoff蛹的形态特征快速、无损、准确鉴别雌雄个体,对其头部、胸部、腹部和体色外部鉴别特征进行了分析,并通过解剖生殖系统验证准确性.结果表明:以春尺蠖蛹的胸部和腹部特征识别雌雄准确率明显高于头部和体色特征,识别率可达100％.首先,雌蛹第8腹节腹板前缘中部具有"Y"型沟,与第7腹节腹板后缘形成倒三角状,而雄蛹无此特征.其次,雌蛹生殖孔与产卵孔连接形成裂缝,两侧平坦无突起,而雄蛹第9腹节腹板中央有一纵裂缝的生殖孔,两侧各有半圆状瘤状突起.最后,雌蛹的胸部背板各节间相对长度均小于雄蛹,而雄蛹中胸背板最宽,其后缘明显向外凸起.因此,春尺蠖蛹胸部或腹部特征可用于快速、准确地鉴别雌雄性别.     

Combination of solvent and radiation effects on degradation of aflatoxin B1

Summary Degradation of aflatoxin B₁ in chloroform, ethyl ccetate and coconut oil were examined by exposing the solvents in the form of thin layers to radiation from the sun and from UV and fluorescent tubes. Solar degradation of aflatoxin B₁ occurred in coconut oil leaving no residual aflatoxin B₁ or any new fluorescent derivatives. Other combinations of solvents and radiation produced up to four new fluorescent degradation compounds. Aflatoxin B₁ did not undergo solar degradation in the absence of moisture. Acidity enhanced solar degradation. A fluorescent derivative produced by solar degradation of aflatoxin B₁ in chloroform degraded further on solar irradiation in coconut oil but not in chloroform.

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Resumen Se examinó la degradación de la aflatoxina B1 en cloroformo, acetato de etilo y aceite de coco, exponiendo los disolventes en forma de capa fina a la radiación solar y a radiaciones procedentes de lámparas UV y fluorescentes. La degradación solar de la aflatoxina B1 tuvo lugar en aceite de coco sin dejar residuos de aflatoxina ni de ningún nuevo derivado fluorescente. Otras combinaciones de disolvente y radiaciones produjeron hasta 4 nuevos derivados fluorescentes. La degradación solar de la aflatoxina B1 no se produjo en ausencia de humedad. La acidez potenció la degradación solar. Uno de los derivados fluorescentes obtenidos en la degradación solar de la aflatoxina B1 en cloroformo continuó degradándose bajo la radiación solar en aceite de coco pero no en cloroformo.

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Résumé La dégradation de l'aflatoxine B1 dans le chloroforme, l'acétate d'éthyle et l'huile de noix de coco a été examinée en exposant les solvents sous la forme de films minces à l'irradiation du soleil, des uv et de tubes fluorescents. La dégradation solaire de l'aflatoxine B1 s'est produite dans l'huile de noix de coco en ne laissant ni aflatoxine B1 résiduelle ni nouveaux dérivés fluorescents. D'autres combinaisons de solvents et d'irradiation ont produit jusqu'à 4 nouveaux dérivés fluorescents de dégradation. L'aflatoxine B1 ne subit pas de dégradation solaire en absence d'humidité. L'acidité augmente la dégradation solaire. Un dérivé fluorescent produit par dégradation solaire de l'aflatoxine B1 dans le chloroforme, s'est dégradé davantage sous l'irradiation solaire dans l'huile de noix de coco mais non dans le chloroforme.

     

A pilot plant for detoxification of aflatoxin B1-contaminated coconut oil by solar irradiation

Summary In coconut oil naturally contaminated with aflatoxin B1, more than 85% of the toxin is present in the soluble form, the remainder occuring in the sediment. This aflatoxin is detoxified when the oil, in a static layer less than 15 mm thick is exposed to solar radiation. A pilot plant, designed to take account of the viscosity and flow characteristics of the oil, was constructed for the exposure of thin layers of oil (2 mm or less) flowing under gravity. At aflatoxin concentrations between 166 and 1250 jug/kg, 75% of the toxin was degraded on exposure to solar radiation of 10 cal/cm²; total detoxification was achieved on repeated exposure. The naturally contaminated coconut oil after exposure to solar radiation did not contain any residual aflatoxins or fluorescent compounds which might have been derived from original aflatoxin B1.

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Resumen Planta pilota para el tratramiento de aceite de coco contaminado con aflatoxina B1 mediante radiation solar y centrifugado En aceite de coco contaminado de forma natural con aflatoxina B1, más del 85% de la toxina se encuentra en forma soluble, el resto permaneciendo en el sedimento. Esta aflatoxina pierde sus propiedades tóxicas cuando se expone el aceite en forma de capa estática de 15 mm de grosor a la radiación solar. Se construyó una planta piloto diseñada teniendo en cuenta la viscosidad y las caracteristicas de fluidez del aceite de forma que pudieran exponerse a la radiación solar capas de aceite muy finas (2 mm o menos) fluyendo gracias a la gravedad. Cuando aceite conteniendo aflatoxina en proporciones entre 166 y 1250 /kg se expuso a una radiación solar de 10 cal./cm² la toxina se degradó en un 75%. La detoxificación total se obtuvo mediante repetición del proceso. El aceite de coco contaminado de forma natural, una vez expuesto a la radiación solar no contenía aflatoxinas residuales ni compuestos fluorescentes potencialmente derivados de la aflatoxina B1 contenida originalmente.

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Résumé Usine-pilote pour la détoxification, par irradiation solaire et centrifugation, de l'huile de coprah contaminée par l'aflatoxine B1 Dans l'huile de coprah spontanément contaminée par l'aflatoxine B1, plus de 85% de la toxine est présente sous forme soluble, le reste se trouvant dans le sédiment. Cette aflatoxine est détoxifiée lorsque l'huile est exposée à la radiation solaire en couche statique de moins de 15 mm d'épaisseur. Une usine-pilote, conçue en tenant compte de la viscosité et de l'écoulement de l'huile, a été construite pour irradier une mince couche d'huile (2 mm ou moins) s'écoulant par gravité. Pour des concentrations en aflatoxine allant de 166 à 1250 g/kg, 75% de la toxine est dégradée par exposition à une irradiation solaire de 10 cal./cm² et, en répétant le traitement, on obtient une détoxification complète. Après exposition à la radiation solaire, l'huile de coprah contaminée spontanément ne contient plus d'aflatoxine résiduelle, ni de composés fluorescents dérivés de l'aflatoxine B1 originelle.

     

Cellular dissection of the degradation pattern of cortical cell death during aerenchyma formation of rice roots

Cellular events which occur prior to cell collapse were examined in the root cortex of rice (Oryza sativa L.) during aerenchyma formation. Cell collapse started at a specific position in the mid cortex. These cells were distinct in shape from those located towards the periphery. Furthermore, cell collapse was preceded by acidification and the loss of plasma-membrane integrity in cells of the mid cortex. Subsequent death of neighboring cells followed a radial path. Microinjection of molecules of different sizes conjugated with fluorescein isothiocyanate (FITC) showed a molecular exclusion limit of between 9.3 and 19.6 kDa in the root cortex. Furthermore, large molecules, i.e. those around 9.3 kDa, were predominantly transferred in a radial direction, which coincided with the path of sequential cell death. Received: 24 April 1997 / Accepted: 4 August 1997