桔小实蝇分子生物学研究中样品采集及保存处理的改进方法

介绍了一种果实蝇,桔小实蝇Bactroceradorsalis的虫样采集和保存处理的方法。利用一种简易的诱捕装置对于野外短时间、大面积采集实蝇虫样效果显著;同时,用TE溶液浸泡的干燥虫样适用于桔小实蝇的DNA抽提和PCR扩增。这种虫样采集和保存方法也适用于果实蝇属其它几类实蝇的分子生物学研究。     

Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropod populations in rice. When used in combination with an enclosure, application of this sampling device provides absolute estimates of the populations of arthropods as numbers per standardized sampling area. The sampling efficiency depends critically on the sampling duration. In a mature rice crop, a two-minute sampling in an enclosure of 0.13 m² yields more than 90% of the arthropod population. The device also allows sampling of arthropods dwelling on the water surface or the soil in rice paddies, but it is not suitable for sampling fast flying insects, such as predatory Odonata or larger hymenopterous parasitoids. The modified blower-vac is simple to construct, and cheaper and easier to handle than traditional suction sampling devices, such as D-vac. The low cost makes the modified blower-vac also accessible to researchers in developing countries.     

Sampling of Aerobiological Material from a Small Aircraft

A sampling device suitable for sampling of pollen, spores and bacteria is described. Sampling in vertical profiles of these substances has been performed over Sweden. Simultaneously, the light scattering coefficient from particles has been measured with an integrating nephelometer. Filter samples collected at the same time have been analysed for particulate sulfate and sulfur dioxide. Results from some measurements in 1976 are pre-sented. An attempt is made to classify the results with ah-mass trajectories and analysis of surface weather maps.     

In situ colonization of polyvinyl chloride, brass, and copper by Legionella pneumophila.

A sampling device (Robbins device) was used to expose brass, copper, and polyvinyl chloride plugs to potable water contaminated by Legionella pneumophila serogroup 1. Plugs were removed at approximately 1-week intervals and cultured. The colonization rates were polyvinyl chloride, 70; copper, 31; and brass, 25%. Quantitative cultures revealed that polyvinyl chloride was most heavily colonized, whereas brass was least colonized. We conclude that materials used in plumbing systems are readily colonized by Legionella and that the Robbins device provides a means for testing such materials in an in situ setting.     

Analysing the performance of a micro soil solution sampling device in a laboratory examination and a field experiment

The performance of a micro soil solution sampling device was tested in a laboratory examination and in a field experiment. The instrument allows detection of temporal and spatial changes in soil solution chemistry at a spatially high resolution. The flexible tube of the suction cell is made of a porous polymer with a diameter of 2.3 mm. To achieve more stability and to minimize disturbance of the instrument during field installation, the original device was modified by embedding the suction cell in a stainless steel and pressure absorbing corpus. During a laboratory test the new sampling system was compared to ceramic P-80 suction cells. Solution samples taken with the new device adapted more quickly to the given concentrations compared to the ceramic suction cells. In a field test, micro samplers were implanted in an existing soil solution monitoring plot, equipped with standard ceramic samplers. Bi-weekly sampling using the micro cells indicated high temporal and spatial variation, and in June 1995 it was possible, to identify a distinct nitrification. However, in a statistical comparison of the entire sampling period and respective sub-sampling areas the two sampler types indicated identical concentration ranges for nitrate. It is concluded that the new micro samplers can help to identify processes in soils which may cause short-term changes in the soil solution chemistry, whereas the standard sampling technique with ceramic cells seems to be still a suitable tool if long-term mean soil solution concentrations are to be measured.     

Local gas holdup measurement in aerated agitated bioreactors

Summary A simple, inexpensive apparatus wholly consisting of readily available components is developed to measure the local volumetric gas holdup in aerated agitated bioreactors based on the principle of phase separation. The device can determine the gas holdup to as low as 0.1% with a measurement error of less than 10%. To prevent under-withdrawing or over-withdrawing the dispersed gas, a sampling rate yielding a superficial velocity at the sampling probe opening equal to 50% of the stirrer tip speed is recommended.     

A reagentless amperometric electrode based on carbon paste, chemically modified with D-lactate dehydrogenase, NAD(+), and mediator containing polymer for D-lactic acid analysis. II. On-line monitoring of fermentation process

The production of D-lactic acid by Lactobacillus delbrueckii (ATCC 9649) during fermentation was monitored on-line with a reagentless D-lactate dehydrogenase modified carbon paste electrode in a flow injection system integrated with a filtration sampling device. The time delay between sampling and detection was approximately 6 min. The use of an electropolymerized ortho-phenylenediamine membrane on the elctrode resulted in a very selective sensor response with acceptable stability and sensitivity. The D-lactate concentrations determined on-line agreed well with those determined by a standard method, suggesting that this sensor system is suitable for on-line monitoring of fermentation processes. (c) 1995 John Wiley & Sons, Inc.     

BioMEMS device with integrated microdialysis probe and biosensor array

The fabrication of a microdevice for continuous sampling and on-line monitoring of glucose is described. The device comprised a microdialysis sampling system integrated on the flow through channel of a microfabricated enzyme sensor. The sensor was produced by thin film technology and was assembled to a printed circuit board (PCB) that provided the means for both electrical and fluidic connections. A polyacrilonitrile fibre, with a cut-off of 50 kDa, was used in the fabrication of the sampling probe. The performance of the device was evaluated in-vitro. High sampling efficiency of the microdialysis probe was achieved by appropriate selection of the perfusion fluid flow rate. Response times varying from 1.5 to 3.0 min were determined for flow rates ranging between 1 and 0.2 micro l/min. The linear response range was up to 30 mM glucose and interference from other electroactive substances was almost negligible. The device showed excellent stability under continuous operation for at least 5 days and sensitivity variation less than 3% over a period of 15 days.     

A pedal corer for the quantitative sampling of sediments and benthic organisms in submerged areas accessible on foot

This paper presents a new device to collect quantitative samples of sediment and benthic organisms. The device is specially designed for sampling with the advantages of box-corer or Eckman dredges in submerged areas that are accessible on foot. The pedal corer is a simple, lightweight, user-friendly device that does not disturb the sediment structure and provides easy access to the sample contained inside the core. With this device, sampling in shallow water zones that are constantly submerged is made easy and sampling time is extended in intertidal zones. Handling editor: J. Saros     

Implantable device for drug delivery and blood sampling in the rat

An implantable drug-delivery and venous sampling device is described that is constructed from a polyvinyl chloride catheter and a rubber intravenous catheter plug coated with Silastic. The implant was used for repeated venous sampling and for both administration of parenteral solutions and injections into the right colon of the rat for periods to 1 mo.     

High-throughput droplet PCR

The polymerase chain reaction has facilitated the ready analysis of nucleic acids. A next challenge requires the development of means to unravel the complexity of heterogeneous tissues. This has presented the task of producing massively parallelized quantitative nucleic acid data from the cellular constituents of tissues. The production of aqueous droplets in a two phase flow is shown to be readily and routinely facilitated by miniaturized fluidic devices. Droplets serve as ideal means to package a future generation of PCR, offering an enhanced handling potential by virtue of reactant containment, to concurrently eliminate both contamination and sample loss. This containment also enables the measurement of nucleic acids from populations of cells, or molecules by means of high throughput, single cell analysis. Details are provided for the production of a prototype micro-fluidic device which shows the production and stable flow of droplets which we suggest will be suitable for droplet-based continuous flow micro-fluidic PCR. Suggestions are also made as to the optimal fabrication techniques and the importance of device calibration.     

Automatic Sampling and Analysis of Organics and Biomolecules by Capillary Action-Supported Contactless Atmospheric Pressure Ionization Mass Spectrometry

Contactless atmospheric pressure ionization (C-API) method has been recently developed for mass spectrometric analysis. A tapered capillary is used as both the sampling tube and spray emitter in C-API. No electric contact is required on the capillary tip during C-API mass spectrometric analysis. The simple design of the ionization method enables the automation of the C-API sampling system. In this study, we propose an automatic C-API sampling system consisting of a capillary (∼1 cm), an aluminium sample holder, and a movable XY stage for the mass spectrometric analysis of organics and biomolecules. The aluminium sample holder is controlled by the movable XY stage. The outlet of the C-API capillary is placed in front of the orifice of a mass spectrometer, whereas the sample well on the sample holder is moved underneath the capillary inlet. The sample droplet on the well can be readily infused into the C-API capillary through capillary action. When the sample solution reaches the capillary outlet, the sample spray is readily formed in the proximity of the mass spectrometer applied with a high electric field. The gas phase ions generated from the spray can be readily monitored by the mass spectrometer. We demonstrate that six samples can be analyzed in sequence within 3.5 min using this automatic C-API MS setup. Furthermore, the well containing the rinsing solvent is alternately arranged between the sample wells. Therefore, the C-API capillary could be readily flushed between runs. No carryover problems are observed during the analyses. The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis. The feasibility of using this setup for quantitative analysis is also demonstrated.     

Automated instrument for measuring biological transport kinetics over intervals of a few seconds

Automated sampling device was designed to permit determination of rates of biological transport of metabolites into cells. The substrate was automatically introduced into a stirred cell suspension at 37°C. The first sample was automatically taken after a mixing interval of 1 sec and nine subsequent samples were taken at programmable intervals (1 to 100 sec). The samples were forced by pressure differential (vacuum) through 0.4 μ pore size membranes and approximately 50 μl were collected in disposable cups. The duration of the sampling interval was controllable down to 0.1 sec. The samples preserved records of the substrate concentrations in solution at the time of filtration. With the use of suitable radioactive labeled isotopes, the changes in substrate concentrations may be conveniently measured by liquid scintillation spectrometry, but other analytical procedures of suitable sensitivity may be used. Initial and steady-state transport rates of succinate and glucose in Escherichia coli were obtained using the device.     

A new sampler for collecting invertebrates in submerged vegetation

A new sampler is described that can rapidly enclose a specific volume of water at a given depth, including submerged macrophytes and associated invertebrates. The sampler is a tong-shaped instrument consisting of two metal rods connected by a flexible joint. At the end of each arm is a metal cylinder (diameter 10 cm); one end of the cylinder has a sharpened edge and the other is equipped with a net. Powerful metal springs force the cylinders together at high speed, and macrophytes are enclosed in the nets. The sampler is suitable for studying vertical and horizontal distribution of invertebrates, even fast-moving taxa, within submerged vegetation. The device causes little disturbance of the vegetation, hence it is also suitable for repeated sampling within mesocosms.     

First steps in robot automation of sampling and sample management during cultivation of mammalian cells in pilot scale

The robot automation of sampling and the subsequent treatment and storage of aliquots during mammalian cell cultivations was investigated. The complete setup, the development and testing of the sampling device, the robot arm, and the cell imaging system are described. The developed sampling device is directly coupled to a pilot bioreactor. It allows the computerized sterile filling of cell broth into 50 mL sample tubes. After each sampling the whole tubing system is steam sterilized. For further off-line treatment a robot takes the sample to the different devices. This robot is equipped with a camera and a force/torque sensor. A color-based object recognition guides the arm in a complex surrounding with different illumination situations, enabling the robot to load the sampling device with tubes and take the sample to further devices. For necessary pipetting and refilling we developed a computerized device. Cells are automatically stained and counted using an imaging system. The cell number and viability is automatically saved in a process control system together with the on-line parameters. During several cultivations in 20 and 100 L scale these main components of the automation strategy were successfully tested.     

Salt drying: a low‐cost,simple and efficient method for storing plants in the field and preserving biological repositories for DNA diversity research

Although a variety of methods have been optimized for the collection and storage of plant specimens, most of these are not suited for field expeditions for a variety of logistic reasons. Drying specimens with silica gel in polyethylene bags is currently the standard for field‐sampling methods that are suitable for subsequent DNA extraction. However, silica‐gel repositories are not readily available in remote areas, and its use is not very cost‐effective for the long‐term storage of collections or in developing countries with limited research budgets. Salting is an ancient and traditional drying process that preserves food samples by dehydrating tissues and inhibiting water‐dependent cellular metabolism. We compared salt and silica‐gel drying methods with respect to dehydration rates overtime, DNA quality and polymerase chain reaction(PCR) success to assess whether dry salting can be used as an effective plant preservation method for DNA analysis. Specimens from eleven plant species covering a variety of leaf structures, leaf thicknesses and water contents were analysed. Experimental work indicated that (i) levels of dehydration in sodium chloride were usually comparable to those obtained when silica gel was used, (ii) no spoilage, fungal or bacterial growth was observed for any of the species with all drying treatments and (iii) good yields of quality genomic DNA suitable for PCR applications were obtained in the salt‐drying treatments. The preservation of plant tissues in commercial table salt appears to be a satisfactory, and versatile method that may be suitable in remote areas where cryogenic resources and silica repositories are not available.     

An assessment of the Sartorius MD8 microbiological air sampler

Tests described in this paper show that gelatine membrane filters used in the MD8 microbiological air sampling system collected monodispersed aerosols between 0·7 and 1·0 μm containing viable Bacillus subtilis var. niger spores, with an efficiency of 99·9995%. Gelatine membrane filters linked to the MD8 control pump system were as effective as the well established Casella slit-to-agar device for collecting some viable bacteria, nebulized under controlled experimental conditions and naturally occurring airborne micro-organisms in a pharmaceutical plant. By using a long flexible hose connection to the control pump, the head could be positioned where sampling was required in locations remote from the pump exhaust, making it suitable for microbiological monitoring in critical locations such as laminar flow stations and isolators.     

Odour sampling 1: Physical chemistry considerations

The selection of an odour sampling device may influence the composition of the resulting odour sample. Limited comparison of emission rates derived from turbulent and essentially quiescent sampling devices confirms that the emission rates derived from these devices are quite different. There is therefore compelling evidence that current odour sampling practice should have greater regard for fundamental physical and chemical principles, the nature of the odour source and the conditions created by the sampling device. Such consideration may identify the most appropriate situations under which the use of these devices may or may not be correct.     

Integrated non-invasive system for quantifying secreted human therapeutic hIL2

Cell encapsulation has been used to treat diabetes, amyotrophic lateral sclerosis, and other chronic ailments by the secretion of therapeutic proteins in vivo. Detection of these proteins typically requires invasive procedures such as blood sampling or device extraction, however. In this article, a non-invasive means of measuring secreted protein concentration using a co-expressed red fluorescent protein marker is developed. A bicistronic expression vector was constructed for the intracellular production of a red fluorescent protein marker and the secreted production of human interleukin-2 (hIL2). The destabilized red fluorescent protein, DsExDR, was selected for its rapid turnover, as well as its ability to emit red light, which is readily transmitted through mammalian tissue. Transfections of this bicistronic vector into three cell lines C2C12, HEK293, and Jurkat showed linear correlations between the expressed proteins, DsExDR (intracellular) and hIL2 (secreted), with transfection DNA concentration. Correspondingly, there was a linear correlation between secreted product (hIL2) and intracellular marker (DsExDR). As transfection DNA was increased, Jurkat cells were found to increase secreted hIL2 in direct proportion to the accumulated DsExDR. HEK293 and C2C12 cells expressed and secreted significantly more hIL2 than the Jurkat cells, while still maintaining a linear relationship. Thus, all three cell lines were suitable hosts for the bicistronic expression of DsExDR and expression and secretion of therapeutic hIL2. This reporting strategy may find the greatest use in cell encapsulation therapy.     

A lightweight microdrive for single-unit recording in freely moving rats and pigeons

A design for an inexpensive and reliable subminiature microdrive for recording single neurons in the freely moving animal is presented. The Scribe microdrive is small and lightweight and has been used successfully to record in freely moving rats and pigeons. It would also be suitable for recording in mice. The device is simple and inexpensive yet allows for stable and precise manipulation of the recording electrodes. As a result it supports stable recordings conducted over long periods. Because the Scribe microdrive is a small-diameter device it is also suitable for multisite, multielectrode applications. Here we discuss the construction of the device and comment on its use in recording from freely moving rats and pigeons.