首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 562 毫秒
1.
The interaction of chromium(III) with poly(dG-dC) inhibits the B to Z transition and results in the condensation of the polymer at high Cr/nucleotide ratios. At low Cr/nucleotide ratios chromium(III) enhanced the ability of ethanol to induce the B to Z transition of poly(dG-dC). The effects of chromium(III) on the conformation of DNA may be related to the carcinogenicity of chromium compounds.  相似文献   

2.
The species of Ardeicola parasitic on the Ibis genus Threskiornis are reviewed-clayae Brelih, freemani sp.n., ibis Le Souef & Bullen, indicus Brelih, intermedia sp.n., nippon Hajela & Tandan-and a key for their identification is presented. Notes on the affinities of the species and a discussion on the distribution of Ardeicola on Threskiornis are included.  相似文献   

3.
The species of Ibidoecus parasitic on the Ibis genus Threskiornis are reviewed-clausus (Giebel), dianae Tandan, insularis sp.n., tandani sp.n., threskiornis Bedford-and a key for their identification presented. The host and geographical distribution of the phthirapteran parasites of this genus are discussed.  相似文献   

4.
刘德旺  张树仁 《西北植物学报》2007,27(11):2320-2322
发现了分布于西藏的2个珍珠茅属新记录种:小型珍珠茅和毛果珍珠茅,并补充记载了2个新记录种的文献和标本引证。  相似文献   

5.
讨论了Clematis eriopoda Maxim.和sect.Atragenopsis Boiss.的地位,认为这二分类群均应成立;描述了2新种,1新变种;过去长期被归并的卷萼铁线莲C.tubulosa得到恢复;Clematisheracleifoliavar.ichangensis被转移改作卷萼铁线莲的变种;首次给出光叶铁线莲Clematisglabrifolia的果实的形态描述。  相似文献   

6.
7.
Although iron (Fe) is an essential element for almost all living organisms, little is known regarding its acquisition from the insoluble Fe(III) (hydr)oxides in aerobic environments. In this study a strict aerobe, Pseudomonas mendocina, was grown in batch culture with hematite, goethite, or ferrihydrite as a source of Fe. P. mendocina obtained Fe from these minerals in the following order: goethite > hematite > ferrihydrite. Furthermore, Fe release from each of the minerals appears to have occurred in excess, as evidenced by the growth of P. mendocina in the medium above that of the insoluble Fe(III) (hydr)oxide aggregates, and this release was independent of the mineral's surface area. These results demonstrate that an aerobic microorganism was able to obtain Fe for growth from several insoluble Fe minerals and did so with various growth rates.  相似文献   

8.
9.
螺旋藻乙醇酸氧化酶(GO)的研究   总被引:3,自引:0,他引:3  
采用比色法对鄂尔多斯高原碱湖的钝顶螺旋藻(S1)与国外引进的钝顶螺旋藻(S2)和极大螺旋藻(S3)的乙醇酸氧化酶(GO)进行了比较研究。结果表明:在25℃、pH 8.0条件下,S1、S2和S3的GO活性分别为70.9 U/gFW、59.6 U/gFW和80.9 U/gFW;最适温度均为30℃;在0℃~35℃(30℃)范围内比较稳定;最适pH值分别为8.6、8.2和8.4;pH值稳定范围,S1为7.6~10.0、S2为8.0~9.0;S3为8.0~8.6。S1的GO对温度和pH适应范围最宽,且在低温、高温、强酸和强碱下的活性均比引进种的高。  相似文献   

10.
Although iron (Fe) is an essential element for almost all living organisms, little is known regarding its acquisition from the insoluble Fe(III) (hydr)oxides in aerobic environments. In this study a strict aerobe, Pseudomonas mendocina, was grown in batch culture with hematite, goethite, or ferrihydrite as a source of Fe. P. mendocina obtained Fe from these minerals in the following order: goethite > hematite > ferrihydrite. Furthermore, Fe release from each of the minerals appears to have occurred in excess, as evidenced by the growth of P. mendocina in the medium above that of the insoluble Fe(III) (hydr)oxide aggregates, and this release was independent of the mineral's surface area. These results demonstrate that an aerobic microorganism was able to obtain Fe for growth from several insoluble Fe minerals and did so with various growth rates.  相似文献   

11.
12.
The distribution of three amblyceran (Menacanthus stramineus, Menacanthus cornutus, Menopon gallinae) and five ischnoceran species (Lipeurus lawrensis tropicalis, Lipeurus caponis. Goniocotes gallinae, Goniodes gigas, Goniodes dissimilis) on poultry was determined. The preferred sites of these species on the host body were recorded.  相似文献   

13.
14.
Poly-(lactide-co-glycolide) (PLGA) is an FDA-approved biodegradable polymer which has been widely used as a scaffold for tissue engineering applications. Collagen has been used as a coating material for bone contact materials, but relatively little interest has focused on biomimetic coating of PLGA with extracellular matrix components such as collagen and the glycosaminoglycan chondroitin sulfate (CS). In this study, PLGA films were coated with collagen type I or collagen I with CS (collagen I/CS) to investigate the effect of CS on the behaviour of the osteoblastic cell line MG 63. Collagen I/CS coatings promoted a significant increase in cell number after 3 days (in comparison to PLGA) and after 7 days (in comparison to PLGA and collagen-coated PLGA). No influence of collagen I or collagen I/CS coatings on the spreading area after 1 day of culture was observed. However, the cells on collagen I/CS formed numerous filopodia and displayed well developed vinculin-containing focal adhesion plaques. Moreover, these cells contained a significantly higher concentration of osteocalcin, measured per mg of protein, than the cells on the pure collagen coating. Thus, it can be concluded that collagen I/CS coatings promote MG 63 cell proliferation, improve cell adhesion and enhance osteogenic cell differentiation.  相似文献   

15.
Nine rainpools in the savanna of northern Bolivia were examined using a random, semi‐quantitative sampling method. Both the macrophyte and insect assemblages showed that the longevity of a pool tended to be the dominant influence on the colonizing biota in the Tropics. Twenty‐four families of insects were recorded, including seven Heteroptera, five Odonata and five Diptera. The highly ephemeral (A‐)pools, which were dominated by beetles, differed from longer‐lived waters (B‐ and C‐pools). The composition of the insect assemblages in the B‐ and C‐pools formed a continuum, and the Chironomidae became more numerous and diverse with increasing water body longevity and habitat complexity. Out of the 20 recorded chironomid genera, three uncommon larval types are presented (Chironomini Gen X, "Tanytarsus”; (b), "Tanytarsus”; (dark L.o.). The study area is among the least researched in Bolivia, so many insects, and the chironomids in particular, are suspected as being newly discovered species.  相似文献   

16.
在实验条件下,系统研究了芬兰真绥螨Euseius finlandicus Oudemans对苹果全爪螨Panony-chus ulmi Koch的控制能力。研究结果表明:(1)在15~32℃的温度条件下,芬兰真绥螨雌成螨的捕食量随着温度的上升呈线型正相关。在15~25℃的温度内芬兰真绥螨的产卵量随温度升高而增加,在15℃下平均单雌产卵0.42粒,25℃时平均单雌产卵2.56粒;当温度升到32℃时单雌产卵下降为1.62粒,雌成螨的产卵量与温度的关系呈抛物线型。(2)在5~15头/叶的猎物密度下,雌成螨的捕食量随着猎物的密度增加呈线型正相关,而当猎物密度达到30头/叶时,芬兰真绥螨雌成螨的捕食量处于平稳状态。在5~15头/叶的猎物密度下,芬兰真绥螨的产卵量和产卵量均与猎物的密度呈线型正相关;当每头雌成螨捕食量为1.8~3.5头时,产卵量为1.0~1.5粒。(3)不同温度下,芬兰真绥螨对猎物的不同密度和虫态的功能反应可用圆盘方程II型进行拟合;在25℃条件下捕食效率最高且喜好捕食的虫态是卵和幼螨。  相似文献   

17.
18.
The virulence of Hirsutella thompsonii (Fischer) to Brevipalpus phoenicis (Geijskes) was evaluated in laboratory, grown on complete and solid culture media (MC-S); complete and liquid culture media (MC-L); rice (APC) and powdered rice (APC-SM). Adults were confined to arenas prepared with citrus leaves in acrylic dishes containing water-agar. Conidial suspensions were prepared at different concentration (3.2 x 10(5) to 1 x 10(7) spores/ml) and applied on mites to establish the table curve-response on fourth day. For field evaluation, adults were maintained in arenas prepared with fruits which were placed in plants. In this test, four treatments were tried: H. thompsonii cultured on rice (APC) at two concentrations (20 kg/ha and 10 kg/ha), H. thompsonii produced by liquid fermentation (MC-L) (5 L/ha) and control (sterile water). Adult survival, number of eggs and nymphs per fruit were observed 10 and 20 days after the fungus application. The lowest LC25 value calculated was from pathogen produced in MC-S (1.9 x 10(5) conidia/ml).The LC25 values calculated to APC and APC-SM did not differ statistically. The LC25 values to MC-L and MC-S were 1.9 x 10(6) infective cells/ml and 2.2 x 10(5) conidia/ml. In the field, concentration and time to death differed between treatments and control. The applications resulted in reduction of adult survival and number of eggs.  相似文献   

19.
20.
The aim of the present study was to assess the effect of six different temperatures on the development of Acarophenax lacunatus (Cross & Krantz) using eggs of Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) as hosts. The temperature affected the development of A. lacunatus. The largest values for the progeny (19 mites in T. castaneum and 15 mites in C. ferrugineus) were obtained at about 30 degrees C, as also observed for the net reproductive rate (Ro), which revealed that the A. lacunatus population increased 18 times in T. castaneum and 14 times in C. ferrugineus in a generation. The intrinsic rate of increase (r m) gradually increased with temperature, reaching the maximum value at 35 degrees C in T. castaneum (1,608) and C. ferrugineus (1,289). The generation time was negatively correlated with temperature, ranging from 1,60 to 4,85 days in T. castaneum and from 1,96 to 5,34 days in C. ferrugineus. These results suggest that the mite A. lacunatus may be used in programs of biological control of T. castaneum and C. ferrugineus in the tropics.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号