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1.
The venom apparatus of the scorpion, C. sculpturatus (Ewing) was studied with light and electron microscopy. Each of the paired glands is lined by secretory epithelium made up of a single layer of columnar cells. Extensive folding in the epithelial layer creates a primitive acinar gland. The secretory products are either membrane-bound or unbound vesicles with discrete morphologies and are observed in the extruded venom, within the lumen of the gland, and within single secretory cells. The venom apparatus, including connective tissues, nerve cells, and muscle tunic is described and correlations are made with observations in other Athropods.  相似文献   

2.
A simple apparatus is described which enables records to bemade of the nutational movements of small amplitude exhibitedby seedling plants. The apparatus described has a resolutionof o.1 mm and 5 minutes. The recording system is capable ofrecording over periods of up to 24 hours' duration automatically. Using this apparatus, numerous recordings have been made ofthe nutation of runner-bean seedlings. The movement exhibitedis considered to be the result of a periodic, oscillatory movement,namely nutation, upon which are superimposed linear movementscaused by tropic responses or random growth irregularities.The apparatus has been found especially useful for the studyof the periodicity of nutation, and a study of the variabilityof this parameter in the nutation of the bean seedling at aconstant temperature has been made as an essential prerequisitefor the study of the effect of experimental treatments. Thevariability has been shown to be high, even within the sameplant.  相似文献   

3.
The equipment used for preparative polyacrylamide gel electrophoresis has been either difficult to construct or costly if purchased commercially. An inexpensive preparative acrylamide gel apparatus and peristaltic pump are described in this paper which are easy to use and may be constructed from readily available materials. The construction of the preparative gel apparatus requires no special machining or glass blowing.This report describes the use of the disc gel apparatus in the final purification step of three binding proteins which appear to be involved in the transport of the branched-chain amino acids in Escherichia coli. Two of these proteins have been described previously (1–4). The apparatus has also been successfully used in a number of other laboratories for the purification of a variety of other proteins (5–9).  相似文献   

4.
Martin Clayton 《Mycologist》2006,20(4):163-169
In the Bibliothèque de l'Institut de France are three albums containing almost 600 drawings of fungi, compiled in Italy the 1620s. Many of these drawings were made using the newly-invented microscope. These albums constitute the finest and most extensive set of mycological illustrations made before the eighteenth century. The three albums have recently been published in their entirety, with all the drawings reproduced in colour.  相似文献   

5.
A new highly sensitivo dondrometor designed principally foruse in the laboratory or in growth rooms is described. The apparatuscaused minimal disturbance to, and distortion of, the stem beingmeasured. Typical readings obtained with the apparatus are showntogether with measurements of sap flux, made with an improvedmagnetohydrodynamic sap flux moter.  相似文献   

6.
Nowadays only digital figures are accepted by the most important journals of taxonomy. These may be produced by scanning conventional drawings, made with high precision technical ink-pens, which normally use capillary cartridge and various line widths. Digital drawing techniques that use vector graphics, have already been described in literature to support scientists in drawing figures and plates for scientific illustrations; these techniques use many different software and hardware devices. The present work gives step-by-step instructions on how to make accurate line drawings with a new procedure that uses bitmap graphics with the GNU Image Manipulation Program (GIMP). This method is noteworthy: it is very accurate, producing detailed lines at the highest resolution; the raster lines appear as realistic ink-made drawings; it is faster than the traditional way of making illustrations; everyone can use this simple technique; this method is completely free as it does not use expensive and licensed software and it can be used with different operating systems. The method has been developed drawing figures of terrestrial isopods and some examples are here given.  相似文献   

7.
A simple apparatus for vertical.,in situ, polyacrylamide or agarose gel casting as well as for the subsequent electrophoresis is described. The apparatus is completely leakproof and does not require any special device like clamps, O-rings, gaskets, grease etc. for sealing. Slab gels of various thickness (0.04 to 1.0 cm) can be made and the apparatus can be used for analytical or preparative purposes. Gel rods can also be cast and run in the device. Forward as well as reverse polarity electrophoresis of a sample can be run simultaneously in the apparatus. NCL Communication No.: 3077.  相似文献   

8.
This study explores the idea that an observer is sensitive to differences in the static traces of drawings that are due to differences in motor origin. In particular, our aim was to test if an observer is able to discriminate between drawings made by a robot and by a human in the case where the drawings contain salient kinematic cues for discrimination and in the case where the drawings only contain more subtle kinematic cues. We hypothesized that participants would be able to correctly attribute the drawing to a human or a robot origin when salient kinematic cues are present. In addition, our study shows that observers are also able to detect the producer behind the drawings in the absence of these salient kinematic cues. The design was such that in the absence of salient kinematic cues, the drawings are visually very similar, i.e. only differing in subtle kinematic differences. Observers thus had to rely on these subtle kinematic differences in the line trajectories between drawings. However, not only motor origin (human versus robot) but also motor style (natural versus mechanic) plays a role in attributing a drawing to the correct producer, because participants scored less high when the human hand draws in a relatively mechanical way. Overall, this study suggests that observers are sensitive to subtle kinematic differences between visually similar marks in drawings that have a different motor origin. We offer some possible interpretations inspired by the idea of “motor resonance”.  相似文献   

9.
Three difficulties encountered by students studying the life cycles of fungi are discussed: (a) Correlating photomicrographs, which sometimes include artefacts, with schematic drawings; (b) Correlating the life cycles of parasitic fungi with those of their hosts and the symptoms of fungal disease; (c) Understanding the cyclic development of fungi, which may have alternating micro- and macro-cycles. A game, developed to help students to overcome these difficulties, is described. Pictures of fungi, as seen by students through microscopes and in their textbooks, have to be correlated in the game with drawings of the fungi. An identification sheet allows students to check their results. Students then have to place cards, on which there are drawings of the different stages in the development of various fungi and their hosts, on a board, so that the parallel stages of host and parasite are next to each other and the photomicrograph drawings form a cycle. In the case of rusts, two cycles have to be produced, and two hosts have to be positioned correctly in the cycles. The game also provides cards to mark seasons and a solution sheet for self-evaluation.  相似文献   

10.
Summary The spinning apparatus of the uloborid spider Polenecia producta was studied to complete previous studies on the same family of spiders. The structure of spinnerets and spigots, under scanning electron microscopy, and the main anatomical and histochemical characteristics of the spinning glands of adult females and males are described. In addition some observations on the spinning apparatus at three successive stages of development are made. There are nine kinds of silk glands in Polenecia, i.e. one more (aciniform — B glands) than found in other uloborids. The spinning apparatus of Polenecia is, therefore, the most complex so far known. It is also more complex than that presently known of Araneoidea. The characteristics of the spinning glands of Polenecia are compared with those of other uloborids. Present knowledge of the spinning apparatus of uloborids leads to a renewed discussion of the origin of the orb web in this family and in araneids. It is concluded that these two types of orb webs emerged from independent evolutionary processes.  相似文献   

11.
《Gene》1997,192(1):191-198
The pathway for binding, processing and transport of transforming DNA into competent cells of Bacillus subtilis is described. The known proteins involved in mediating these processes are reviewed in turn, including several that resemble proteins required for type-IV pilus assembly and function, and those involved in protein secretion. Based on the phenotypes of null mutations in the cognate genes for these proteins, on similarities to other proteins and on membrane localization and topology data, proposals are made for the roles of the individual proteins in the transformation process. A dynamic model is suggested for the presentation of transforming DNA to the transport apparatus.  相似文献   

12.
This article focuses on the cultural and artistic value of a collection of Torres Strait Islander drawings that were commissioned and collected in the late 19th century. I argue that these drawings, made during Alfred C. Haddon's “salvage anthropology” expeditions, can provide insight into the nature of Islander graphic systems and the production of contemporary Islander art. By focusing on stylistic links between the drawings and other forms of decorative art, and their role as resources and inspiration for contemporary Islander artists, I explore the role these collections play in investigating regional artistic traditions, and how they act as agents in reaffirming Islander identity.  相似文献   

13.
A new species of the genus Ronderosia Cigliano 1997 is described. Color illustrations of the female and male, drawings of female and male external genitalia as well as drawings of its phallic structures and photographs of the chromosomes are included.  相似文献   

14.
This work describes a new apparatus for growing fungi and other microorganisms on liquid nutrient media in a Petri dish. The apparatus is composed of a net supporting a cellophane membrane stretched between an outer and an inner ring that is placed inside a Petri dish. This modification of the standard Petri dish offers many advantages for studying growth, metabolism, differentiation, and other aspects of fungi in liquid cultures with minimal waste of expensive chemicals. Monitoring of excreted or absorbed substances by the fungi, the aseptic transfer of undisturbed fungal colonies from dish to dish, and harvesting are made easier, using this apparatus.  相似文献   

15.
For more than 175 years, the remarkable botanical drawings made in Canton by a Chinese artist working with the British East India Company supercargo John Bradby Blake, were handed down from generation to generation within the same family. They first appeared publicly in 1959 when the estate of Sir Frederick Cripps of Ampney Park, Gloucestershire, came up for auction. A Bristol art dealer bought the drawings, but on the other side of the Atlantic, Paul Mellon had other ideas for them. This article follows the trail from London, via Ampney Park and Bristol, to Oak Spring, Virginia.  相似文献   

16.
An apparatus utilizing a force and displacement transducer is described for the direct and long-term recording of the motility in vitro of Fasciola hepatica. Normal movement is typically rhythmical, with bursts of more powerful contractions alternating with periods of lesser activity. Such rhythms and the overall level of activity are maintained for more than 30 hr. The fluke remains active for much longer periods of time: recordings of fluke movements have been made for up to 4 days. Potential damage to the fluke caused by the attachment system within the recording apparatus has been determined by the Evans' Blue Technique and scanning electron microscopy. It is restricted to the attachment sites, and does not spread to other parts of the body over the 30-hr normal activity period. Transmission electron microscope studies have shown that the tegument retains its structural and functional integrity over this period of time. There are advantages of the recording apparatus over previous kymographic methods for studying fluke motility.  相似文献   

17.
Jenő Kontschán 《Biologia》2009,64(4):737-741
Chelonuropoda africana sp. n. is described with original drawings and scanning micrographs. New records of two other Uropodina species, Neodiscopoma crenulatum Marais et Theron, 1986 and Rotundabaloghia feherdii Kontschán, 2004 from Kenya are given.  相似文献   

18.
Its topography is one of the most characteristic features of the Golgi apparatus and the reticular nature of this organelle is evident in Golgi's first drawings, in light microscopic enzyme cytochemical preparations, and in high voltage electron micrographs of thick sections. Although individual components of the Golgi apparatus may differ in staining characteristics, morphology, contents, and enzymatic activities, they are integrated into a dynamic topographical and functional unit that is closely associated with the endoplasmic reticulum. Modulation of enzymatic activities and morphological and enzymatic heterogeneity are not surprising in an organelle that is the site of both synthetic and digestive events, including glycosylation, sulfation, formation of secretory granules and lysosomes, and the degradation of endocytized material.  相似文献   

19.
李惠中  李玉 《菌物学报》1990,9(Z1):89-92
本文报告了粘菌一新种,小囊散丝菌Dianema microsporangium sp. nov.,讨论了新种与本其它种的区别,模式标本保存在中国科学院微生物研究所真菌标本室.散丝菌属在中国首次报导。  相似文献   

20.
Sex differences are recognized in children's free drawings with respect to motifs, colors, figure compositions, and expression. Boys tend to draw mobile objects and mechanical objects with dark or cold colors and often use bird's-eye-view composition when they draw pictures, whereas girls like to draw human motifs (especially girls and women), flowers, and butterflies with light and warm colors and tend to arrange motifs in a row on the ground. Analyses were made on the drawings of girls with congenital adrenal hyperplasia (CAH) and unaffected boys and girls, using masculine and feminine indexes. Sex difference in masculine and feminine indexes was clear in the drawings by unaffected boys and girls. Their drawings do not or mostly do not contain characteristics typical of the opposite sex. Compared with those of unaffected girls, the pictures of CAH girls more strongly showed masculine characteristics. The feminine index for the pictures of CAH girls was significantly lower than that for unaffected girls, while the masculine index for CAH girls was significantly higher than that for unaffected girls. Furthermore, the masculine index for CAH girls was not significantly different from that of unaffected boys. These results suggest that androgen exposure during fetal life may contribute to shaping masculine characteristics in children's free drawings.  相似文献   

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