Thursday, July 31, 2014

Applications: Measuring Tryptophan UV Fluorescence with the CLARIOstar

Tryptophan 3-D Model

Tryptophan is an essential amino acid that is also a precursor for other compounds important for normal function such as vitamins. Furthermore, tryptophan has been characterized for its fluorescent characteristics which have been employed in research endeavors such as protein folding analysis. BMG LABTECH has now characterized our newest instrument the CLARIOstar for its ability to perform tryptophan detection. The results of this characterization are presented in Application Note 254:' Tryptophan quantificaiton using UV fluorescence measurements on the CLARIOstar mult-mode microplate reader'.

The CLARIOstar has a unique system for wavelength selection with its LVF monochromator and  can use filters when necessary. In this application note another unique capability of the CLARIOstar is on display, it can combine the use of filters and monochromator! In this case a filter was used for UV excitation at 280 nm and the monochromator used to detect emission at approximately 360 nm. Furthermore, the CLARIOstar can automatically select the appropriate dichroic setting with its adjustable dichroic. The results for tryptophan sensitivity obtained with a filter in combination with the monochromator were compared to those obtained with filters alone and showed again the filter-like performance of the LVF monochromator!

For more information on the capabilities of the CLARIOstar please visit:

For a copy of this application note please the visit the Applications Center on BMG's website.

Monday, July 28, 2014

New study provides evidence for direct role of epigenetic changes in cancer development

Epigenetics, the ability to change a genes expression without changing the DNA sequence, has long been proposed as a mechanism to turn off the expression of certain genes and thus lead to cancer in a fashion similar to that seen as the result of a genetic mutation. However, until now direct evidence that this was indeed the case was lacking. In a recent article in the Journal of Clinical Investigation, scientists at Baylor College of Medicine describe the creation of a mouse model that provides evidence that epigenetic changes, specifically DNA methylation, can cause cancer.

This work appears in the article entitled: 'Targeted p16Ink4a epimutation causes tumorigenesis and reduces survival in mice'. The article describes the modification of the promoter for p16, an important tumor suppressor gene, such that DNA methyltransferases were attracted to this site and hypermethylation occured, with the anticipated result of p16 gene silencing. The authors provide a variety of controls to indicate that the loss of p16 is due to hypermethylation of its promoter and show that the result of this loss was a higher incidence of cancer and reduced rate of survival.

This image shows a DNA molecule that is methylated
 on both strands on the center cytosine.
DNA methylation plays an important role for epigenetic
gene regulation in development and cancer.
by Christopher Bock
This work represents just the latest evidence of the importance of epigenetic study. We at BMG recognize this importance and the resulting need for tools to identify possible epigenetic treatments. This is why we have recently published application notes which employ the PHERAstar FS to identify possible modifiers of epigentic enzymes.

For more information on how microplate readers from BMG LABTECH can help with epigenetic or other screening assays please visit our website:

Some information for this post was obtained from the Science Daily article: 'Epigenetic changes can drive cancer, study shows'

Original article citation: Da-Hai Yu, Robert A. Waterland, Pumin Zhang, Deborah Schady, Miao-Hsueh Chen, Yongtao Guan, Manasi Gadkari, Lanlan Shen. Targeted p16Ink4a epimutation causes tumorigenesis and reduces survival in miceJournal of Clinical Investigation

BMG LABTECH application notes:

247 Screening for Histone Deacetylase (HDAC) Active Compounds

249 Assessing Epigenetic Enzyme Activity using HTRF® Epigenetic Assays from Cisbio with the PHERAstar FS from BMG LABTECH

Thursday, July 3, 2014

Applications: Assessing Snake Venom for Hemoglobin-modifying Activity

BMG LABTECH in cooperation with Venomtech recently released an application note which describes the use of the PHERAstar FS to create a simple 384 well test for the ability of snake venom to modify hemoglobin. Although snake venom is well characterized to effect hemostasis, there is little literature covering the direct effect of venom on hemoglobin.
A time-dependent change in hemoglobin absorbance is
seen when mixed with the venom for the black-necked
spitting cobra

In this application note the spectrometer available on the PHERAstar FS was employed to obtain the absorbance spectrum from 400-700 nm of samples blood samples treated with venom from a variety of snake species. Using BMG LABTECH's ultra-fast spectrometer these readings can be obtained in less than one second per well.

The results showed that characteristic absorbance peaks for blood at 540 and 570 nm were lost in the presence of the venom from some snake species. Furthermore, the effect was time dependent. Based on this and other evidence the observed effect is believed to be enzyme-mediated.

For more information please go to the BMG LABTECH website and visit the Applications Center.

Application note # 251: Identification of novel haemoglobin-modifying activity in snake venom libraries using the PHERAstar FS

Wednesday, July 2, 2014

Brighter fluorescent proteins could improve biotechnology applications

Green fluorescent proteins (GFP's) and their various relatives with other colors have become important tools for tracking gene expression and monitoring protein-protein interactions, as well as other applications. A recent study in Scientific Reports could improve our understanding of how GFP's can be brighter and therefore improve the signal-to-noise in these applications.

GFP structure
by Richard Wheeler
The results of this study are found in the article entitled: 'Spectral and structural comparison between bright and dim green fluorescent proteins in Amphioxus'. This paper is a detailed analysis of the GFP's in Amphioxus, a small marine invertebrate also know as lancelets. This animal has two forms of GFP, one which is very bright, in part due to 100% quantum efficiency and one that has low (0.1%) quantum efficiency. The comparison of these two GFP's showed that in the bright GFP the interaction of 3 amino acids yielded a change in protein conformation and increased stability which are believed to improve GFP brightness. The authors believe that by understanding the relationship between structural environment and the level of brightness current FP's can be made brighter thus improving their performance in a wide variety of biotechnology applications.

Many of the GFP biotechnology applications can be performed on microplate readers like those from BMG LABTECH!

Original article: E.K. Bomati, et al, Spectral and structural comparison between bright and dim green fluorescent proteins in AmphioxusScientific Reports, 2014; 4

Some information for this post was taken from the Science Daily article: Behind a marine creature's bright green fluorescent glow