Collection of Biological Samples for DNA Analysis

2007 ◽  
pp. 153-166 ◽  
Author(s):  
Jeffery M. Vance
2014 ◽  
Vol 12 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Magdalena M. Buś ◽  
Marie Allen

2021 ◽  
Vol 318 ◽  
pp. 110639
Author(s):  
Ajay Parkash Balayan ◽  
Vivek Kumar ◽  
Prateek Pandya ◽  
Uma Kanga ◽  
Tulika Seth ◽  
...  

2021 ◽  
Vol 43 ◽  
pp. 1-15
Author(s):  
Victor S. Lukarevskiy ◽  
Svyatoslav V. Lukarevskiy ◽  
Sergey A. Kolchin ◽  
Alexey Yu. Oleynikov

In 2011–2013, we surveyed the population structure, spatial distribution and the number of tigers in Southwestern Primorye (about 5000 km2). The total number of tigers, according to winter route census, DNA analysis and camera trapping was estimated at 24–25 adults and 6–7 cubs, belonging to four different litters. The location of tigers is mainly confined to areas difficult to access for people, and with a high density of ungulates. Tigers concentrated in the habitat strip bordering China, mainly comprising the 'Land of the Leopard' National Park. A few tiger tracks were recorded outside of protected areas and on hunting tenures. Current methods for estimating tiger numbers needs critical reflection. Winter census by tracks in the snow is often largely influenced by subjectivity. The main reason for this is the large number of surveyors of various degrees of qualification and as a result the conflicting interpretation of track identification. In our opinion, the most objective results are obtained from a consistent survey of the territory by a limited number of specialists and daily adjustments of collected materials. Precise and informative methods for determining the number and the structure of tiger populations are DNA analysis of biological samples combined with camera trap census. However, a number of significant drawbacks limits their widespread use: this method is labor-intensive and results in high project costs. In addition, weather conditions can greatly affect the preservation of DNA in the samples. There is a need to organize additional survey routes for installing camera traps and detecting of biological samples in order to register the tigresses with young, as they are behavior is often distinguished by a more secretive lifestyle. As a rule, female tigers with young avoid the main movement routes of adult tigers. These methods are expedient only in the smaller survey plots of model areas.


Author(s):  
W. R. Schucany ◽  
G. H. Kelsoe ◽  
V. F. Allison

Accurate estimation of the size of spheroid organelles from thin sectioned material is often necessary, as uniquely homogenous populations of organelles such as vessicles, granules, or nuclei often are critically important in the morphological identification of similar cell types. However, the difficulty in obtaining accurate diameter measurements of thin sectioned organelles is well known. This difficulty is due to the extreme tenuity of the sectioned material as compared to the size of the intact organelle. In populations where low variance is suspected the traditional method of diameter estimation has been to measure literally hundreds of profiles and to describe the “largest” as representative of the “approximate maximal diameter”.


Author(s):  
C. F. Oster

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.


Author(s):  
Patrick Echlin

A number of papers have appeared recently which purport to have carried out x-ray microanalysis on fully frozen hydrated samples. It is important to establish reliable criteria to be certain that a sample is in a fully hydrated state. The morphological appearance of the sample is an obvious parameter because fully hydrated samples lack the detailed structure seen in their freeze dried counterparts. The electron scattering by ice within a frozen-hydrated section and from the surface of a frozen-hydrated fracture face obscures cellular detail. (Fig. 1G and 1H.) However, the morphological appearance alone can be quite deceptive for as Figures 1E and 1F show, parts of frozen-dried samples may also have the poor morphology normally associated with fully hydrated samples. It is only when one examines the x-ray spectra that an assurance can be given that the sample is fully hydrated.


Nature China ◽  
2007 ◽  
Author(s):  
Wei Zeng
Keyword(s):  

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