An evaluation of techniques for measuring yield turgor in excised Salix leaves

Abstract. The use of three techniques for determining yield turgor in excised Salix leaves was investigated. These were the osmotic-solutions technique, the psychrometer technique, and the pressure-chamber technique. The application of the osmotic-solutions technique to a range of leaf types was discussed and the appropriate corrections for volume changes and the contribution of apoplastic water were detailed. It was concluded that the osmotic-solutions technique is not satisfactory for use with slowly growing and/or very elastic leaves. The psychrometer and pressure-chamber techniques were both simple compared with the osmotic-solutions technique, and gave values for yield turgor in the range of 0·3–0·5 MPa. A disadvantage of the psychrometer technique for field applications is that it requires one psychrometer chamber per sample. The pressure-chamber technique was modified for use as a field technique where multiple sampling could be easily and inexpensively achieved. Particular care was required with this technique to prevent water loss from the leaf during stress relaxation, but simple and effective procedures for doing so were found. The modified pressure-chamber technique described here, is recommended as the preferred technique for measuring the yield turgor of leaves in experiments where many simultaneous estimates of yield turgor are to be made.     

Silicon cellular morphology

We describe a design technique for neuromorphic engineering that exploits both Mead's notion of physical equivalence between transistors and ion channels and the intrinsic properties of the materials of which transistors are composed. This is in contrast to the "algorithmic" design technique in common use. A "physical" design technique allows us to emphasise the morphology of cells. We hope to use this in an exploration of the effect of cell morphology upon function.     

Enumeration of rhizobia by enzyme-linked immunosorbent assay (ELISA)

The use of the enzyme-linked immunosorbent assay (ELISA) to enumerate rhizobia in peat carrier and in soil has been investigated. The ELISA technique takes less time than the conventional plant infection technique often used to enumerate rhizobia present in the presence of other micro-organisms. A minimum of 10₂–10₃ cells are required for a detectable ELISA reaction, limiting the use of this technique when the number of rhizobia is low.     

生态学与医学中的整合分析(Meta-analysis)

整合分析是针对一系列独立研究结果进行定量综合分析的方法。自从 1976年 Glass在心理学研究中提出以来 ,该方法已经在许多学科特别是医学领域进行了广泛的应用。 2 0世纪 90年代 ,整合分析被引入生态学研究 ,引起了生态学家和统计学家的广泛关注。在我国 ,该方法也于 1998年被引入生态学。由于生态学研究自身的特点 ,整合分析在应用时出现了许多新问题 ,如不同研究类型的数据抽提与转换、效应值的构建、研究间相关性的估计、出版偏见的评估与修正等 ,为此以整合分析应用最活跃的医学领域进行对比和借鉴 ,分析该方法在两个研究领域应用的范围和特点 ,讨论影响其在生态学中应用的各种因素 ,并着重阐述和探讨其在生态学应用中存在的问题和发展前景     

Pyrosequencing for microbial typing

Pyrosequencing is a real-time DNA sequencing technique generating short reads rapidly and inexpensively. This technology has the potential advantage of accuracy, ease-of-use, high flexibility and is now emerging as a popular platform for microbial typing. Here, we review the methodology and the use of this technique for viral typing, bacterial typing, and fungal typing. In addition, we describe how to use multiplexing for accurate and rapid typing.     

Use of specific Bordetella pertussis antibodies in immunoenzyme analysis for detecting the pertussis antigen

The competitive EIA technique with the use of peroxidase-labeled B. pertussis antigen has been developed. The data obtained in our investigations suggest the possibility of using this technique for the detection of B. pertussis antigen in faucial smears obtained from patients.     

Laser deepithelialization: an adjunct to reduction mammaplasty

A new use is described for the CO2 laser--that of deepithelialization. Deepithelialization is a technique used in a myriad of plastic surgical procedures. This paper introduces the use of the laser for deepithelialization and illustrates its advantages in 44 consecutive patients undergoing reduction mammaplasty. Advantages are the precise removal of the upper dermis and epidermis--a true deepithelialization--with preservation of the lower dermis and pilosebaceous units. Associated decreased blood loss and more rapid operating time without an increase in complications makes this an attractive adjunctive technique with a wide variety of applications. No adverse effects or contraindications to the use of the CO2 laser for deepithelializing have been found.     

A method for immunocytochemical identification of biocytin-labeled neurons following intracellular recording

Because of the large number of cell phenotypes in the nervous system, it has been difficult to characterize each as to specific electrophysiological properties. We have developed a technique that allows the identification of central and peripheral nervous system neurons following intracellular recording. We use electrodes that contain 2% biocytin to do current- and voltage-clamp recordings; the recorded neurons are revealed with streptavidin-fluorescein isothiocyanate labeling and identified through immunohistochemical staining for specific antigens. Presently, we report on the use of this technique to identify four cell types--dopamine, beta-endorphin, vasopressin and oxytocin--in the hypothalamus of the mammal. This technique should have widespread applicability for electrophysiologists.     

A high-throughput protocol for extracting high-purity genomic DNA from plants and animals

DNA extraction techniques that employ the reversible binding of DNA to silica via chaotropic salts can deliver high-quality genomic DNA from plant and animal tissues, while avoiding the use of toxic organic solvents. Existing techniques that use this method are either prohibitively expensive, or are applicable to only a restricted set of taxa. Here we describe a cost-effective DNA extraction technique suitable for a wide range of plant and animal taxa that yields microgram quantities of high-molecular-weight genomic DNA at a throughput of 192 samples per day. Our technique is particularly robust for tissue samples that are insoluble or are rapidly discoloured or oxidized in standard DNA extraction buffers. We demonstrate the quality of DNA extracted using this method by applying the amplified fragment length polymorphism technique to plant species.     

Diagnostic techniques for transvaginal-transuterine aspiration of bovine fetal fluid during the early fetal period

Studies were designed to evaluate 2 methods for transvaginal-transuterine collection of bovine fetal fluids. The first technique (direct) required simultaneous transrectal palpation and retraction of the gravid uterus and direct, intravaginal manipulation of a needle and vacuum tube assembly. The direct technique was only suitable for use in multiparous animals and was attempted when fetal age ranged from Day 55 to Day 75. The second technique (indirect) may be used in primiparous cows, because aspiration was accomplished through a plastic infusion pipet, altered by attachment of a needle to its tip. When this technique was used, fetal age ranged from Day 50 to Day 65. The direct technique provided more control over needle placement and resulted in a higher success rate for aspiration of fetal fluid following single needle penetration (77 versus 50%). Both techniques were associated with rates of abortion (3 13 for the direct and 4 10 for the indirect) that were judged to preclude prospective use in diagnostic strategies for first trimester fetal wastage. Within the controlled study, the diagnostic quality of the aspirate was determined. It was concluded that the altered pipet technique provided aspirates that were of diagnostic, noncontaminated quality. Field use of fetal fluid aspiration following discovery of nonviable pregnancies by B-mode ultrasonography is discussed.     

Giemsa-11 technique. Applications in the chromosomal characterization of hematologic specimens

Summary Use of the Giemsa-11 procedure for the localization of heterochromatic regions of human chromosomes and for differentiation of primate and rodent chromosomes has been somewhat limited since its discovery in 1972. An adaptation of this technique to the cytogenetic characterization of hematologic specimens has aided in the interpretation of translocations, deletions, and inversions involving human chromosome 9. The chromosomal analyses of 10% of over 100 patients, principally leukemic, were aided through the use of this auxiliary procedure. The diseases of these patients are given and portions of karyotypes are presented to show clarification of abnormalities made possible through the use of the Giemsa-11 technique.     

Numerical inversion of the Perrin equations for rotational and translational diffusion constants by iterative techniques.

An iterative numerical technique is presented which allows the semiaxes for prolate and oblate ellipsoids to be determined from the Perrin equations for rotational and translational diffusion constants. The use of this inversion technique is illustrated by application to the proteins: lysozyme, bovine serum albumin, human transferrin, and bovine rhodopsin solubilized in digitonin.     

High-performance liquid chromatography in enzymatic analysis: Opening lecture

During the previous two decades, high-performance liquid chromatography (HPLC) has proven to be an extremely useful technique with which to study the activity of enzymes and this paper will explore some of these uses. The success of the method can be seen not only from the increase in the number of papers utilizing this technique but also from the insights gained from its use on cellular phenomena. Given this success, it is no wonder that HPLC has become the technique of choice for many biologists seeking a more quantitative understanding of biological processes. Based on past experience, there is every reason to expect that the application of HPLC to the assaying of enzymatic activities will usher in another era of fundamental discoveries in the biological sciences. HPLC is particularly well suited to the assay of one activity in the presence of other activities obviating the need for extensive and tedious purification of biological samples. This advantage makes this technique particularly well suited to those who wish to use enzymes as markers for cellular processes, as indicators of metabolic activity and as evidence of gene function. To date, well over 100 activities have been assayed by this method. The method is particularly suited to problem-solving especially in such cases as when the presence of competing reactions prevents the recovery of the expected reaction products. Of the many applications, examples will be given on the use of HPLC for (1) monitoring the activity of an enzyme in a cell-free system, (2) monitoring the flow of metabolites through a multienzyme system and (3) the detection and study of new enzymatic activities. Some generalizations about the use of HPLC methods for the analysis of enzymatic activities will be presented.     

Multiplex Ligation-dependent Probe Amplification (MLPA) et sondes « à façon » entièrement synthétiques. Guide pratique,recommandations et expérience au CHU de Grenoble

Multiplex Ligation-dependent Probe Amplification (MLPA) is a powerful technique for gene dosage quantification. This technique is based on the ligation followed by PCR amplification of two adjacently hybridising oligonucleotides. Its reliability and effectiveness have been proven and is now well established. Besides the commercial kits are distributed by the patentee, MRC-Holland?, it makes it possible to utilise custom-designed MLPA probes for a targeted use of this technique. This strategy has opened the field of MLPA for various applications ranging from diagnostic of rarest pathologies to confirmation of a CGH-detected abnormalities. However, it may be difficult to develop without a solid experience. Here, we detail the guidelines and recommendations for designing custom MLPA probes and illustrate their use in our laboratory.     

Somaclonal variation--genetic basis and breeding applications

Somaclonal variation, the recovery of genetic changes in plants regenerated from tissue culture, offers an opportunity to uncover natural variability and to use this variability for the development of new varieties. This review focuses on the unique variation generated by this technique and the current use of somaclonal variation to develop new plant varieties.     

Microscope fluorometric investigations on the reticulocytic maturation distribution as diagnostic criterion of disordered erythropoiesis.

A microscope fluorometric technique is described which permits not only the visual identification of reticulocytes under the fluorescence microscope but also the determination of their relative stage of maturation to normocytes. The technique is based on a specific staining procedure which results in a fluorescent complex between the reticulocytic RNA and acridine orange. Thus, the relative mass of RNA in the individual reticulocytes can be measured by means of mciroscope fluorometry. As the reticulocytic RNA content decreases and finally disappears during the final maturation process of reticulocytes after their release into the peripheral blood stream, the fluorescence signal indicates the relative degree of this maturation. A characteristic frequency distribution of this parameter can be obtained for a given blood sample by microscope fluorometry measuring 200 to 300 reticulocytes. The preliminary use of this technique for following up the course of two cases of hemolytic anemia and one of pernicious megaloblastic anemia during their treatment demonstrates the potential diagnostic value of this technique of identifying the change of the reticulocyte maturation distribution in addition to the reticulocyte count. Satisfactory agreement between the microscope fluorometric results and those obtained by counting separately the four reticulocytic maturation stages according to Heilmeyer and Wesb?user has been achieved. The possibility of obtaining quantitative and comparable results by use of this method may be considered a general advantage and a promising basis for the development of an automated technique.     

Feeding and trapping fish withPiper auritum

The “natives” at Rio Indio, on the central Caribbean slope of Panama, trap the river fishBrycon chagrensis using leaves ofPiper auritum as bait in feeders. The people use this technique because the fish tastes like the leaf after it has fed regularly on the leaf. This technique has potential use in aquaculture. The plant could also be cultivated for marketing as a food-flavoring condiment and fish food.     

Histochemical localization of ornithine decarboxylase with a labelled suicidal enzyme inhibitor

We describe a new technique for cytochemical localization of ornithine decarboxylase by the use of a synthesized conjugate of rhodamine bound to α-difluoromethylornithine a suicidal inhibitor of the enzyme. The labelled inhibitor retained its specificity and irreversibility towards ornithine decarboxylase inhibition. Using this technique we have localized the enzyme in specific regions of the developing rat cerebellum. This novel technique may be generally applicable to other enzymes.     

Evolution of technique of the direct transblepharoplasty approach for the correction of lower lid and midfacial aging: maximizing results and minimizing complications in a 5-year experience

During the past 5 years, the authors have used a direct trans-lower lid blepharoplasty subperiosteal approach to the lower lid and midface for the purpose of correction of midfacial aging in 757 patients. In a smaller but significant group, this approach has proven valuable in difficult reconstructive situations. The purpose of this article is twofold: (1) to provide a comprehensive retrospective evaluation of the value and promise of the technique and (2) to provide a comprehensive discussion of the pitfalls and complications that have been associated with use of this technique. In addition, technical modifications that may lower the rate of morbidity associated with the use of the procedure are described.     

When 2D is not enough,go for an extra dimension

The use of an extra SDS separation in a different buffer system provide a technique for deconvoluting 2D gel spots made of several proteins (Colignon et al. Proteomics, 2013, 13, 2077–2082). This technique keeps the quantitative analysis of the protein amounts and combines it with a strongly improved identification process by mass spectrometry, removing identification ambiguities in most cases. In some favorable cases, posttranslational variants can be separated by this procedure. This versatile and easy to use technique is anticipated to be a very valuable addition to the toolbox used in 2D gel‐based proteomics.