			Home About us Contact

Probe Complementary (probe + complementary)

Distribution by Scientific Domains

Life Sciences	50%
Chemistry	50%

Selected Abstracts

cDNA nucleotide sequence coding for stearoyl-CoA desaturase and its expression in the zebrafish (Danio rerio) embryo,

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2003
S.L. Hsieh
Abstract A cDNA sequence of stearoyl-CoA desaturase (SCD) was determined from zebrafish (Danio rerio) and compared to the corresponding genes in several teleosts. Zebrafish SCD cDNA has a size of 1,061 bp, encodes a polypeptide of 325 amino acids, and shares 88, 85, 84, and 83% similarities with tilapia (Oreochromis mossambicus), grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio), and milkfish (Chanos chanos), respectively. This 1,061 bp sequence specifies a protein that, in common with other fatty acid desaturases, contains three histidine boxes, believed to be involved in catalysis. These observations suggested that SCD genes are highly conserved. In addition, an oligonucleotide probe complementary to zebrafish SCD mRNA was hybridized to mRNA of approximately 396 bases with Northern blot analysis. The Northern blot and RT-PCR analyses showed that the SCD mRNA was expressed predominantly in the liver, intestine, gill, and muscle, while a lower level was found in the brain. Furthermore, we utilized whole-mount in situ hybridization and real-time quantitative RT-PCR to identify expression of the zebrafish SCD gene at five different stages of development. This revealed that very high levels of transcripts were found in zebrafish at all stages during embryogenesis and early development. Mol. Reprod. Dev. 66: 325,333, 2003. © 2003 Wiley-Liss, Inc. [source]

Detection of Coconut cadang-cadang viroid sequences in oil and coconut palm by ribonuclease protection assay

ANNALS OF APPLIED BIOLOGY, Issue 1 2009
G. Vadamalai
Abstract A ribonuclease protection assay (RPA) has been developed for detecting Coconut cadang-cadang viroid (CCCVd) sequences. An RNA probe complementary to full-length CCCVd246 was used, terminating at nucleotide 65 in the upper conserved region, and linked to a non-viroid 5, sequence, which acted as an internal control for ribonuclease activity. Extracts from CCCVd-infected coconut (Cocos nucifera) and African oil (Elaeis guineensis) palms protected three major fragments of approximately 250, 125 and 50 nt and a variable number of minor fragments. Extracts of healthy coconut palms, Potato spindle tuber viroid -infected tomato and transfer RNA did not protect the probe. The approximately 250 nt fragment is predicted to indicate the presence of monomers and dimers of circular CCCVd246, linear CCCVd246 with the same termini as the probe and point mutants of these forms. The origin of smaller protected fragments is discussed. RPA-detected CCCVd sequences in 13 of 18 oil palms surveyed in a commercial plantation in Malaysia. Signal intensity varied between the positive oil palms and was generally lower than in coconut palms infected with CCCVd. An infection phenotype was implied but not confirmed by the observation that in a group of 10 oil palms with orange leaf spotting, 9 contained CCCVd, whereas in a group of 8 palms without orange spotting, the viroid was detected in 4. Of four coconut palms in Sri Lanka shown by dot-blot assay to contain CCCVd-related RNA, one was shown by RPA to be positive for the CCCVd246 sequence. RPA is therefore a robust and sensitive test for CCCVd sequences, and our results show that sequences closely related to CCCVd246 are not confined to the Philippines. [source]

Unconventional method based on circular dichroism to detect peanut DNA in food by means of a PNA probe and a cyanine dye

CHIRALITY, Issue 9 2005
Stefano Sforza
Abstract In this paper we report an innovative and unconventional method based on circular dichroism for the identification of peanut DNA in food, which can be detected after PCR amplification at the nanomolar level by using an achiral PNA probe complementary to a tract of the peanut Ara h 2 gene and an achiral 3,3,-diethylthiadicarbocyanine dye [DiSC2(5)]. Peanuts are one of the most common causes of severe allergic reactions to foods and are particularly dangerous when they are "hidden" (undeclared) in food. For better protection of consumers, detection methods are required to specifically detect the presence of hidden allergens in a wide variety of food items. Alternative to the detection of the proteins is the determination of species-specific DNA, which is more resistant to technological treatments. PNAs are very specific probes able to recognize DNA sequences with high affinity and evidence for the binding can be obtained by using the DiSC2(5) dye, which aggregates onto the PNA,DNA duplex giving rise to a characteristic visibile band at 540 nm. Because the PNA,DNA duplex is in a right-handed helical conformation, the aggregation of the dye to the duplex gives also rise to a strong CD signal in the 500,600 nm region with a strong exciton coupling due to the formation of multimeric species, since the handedness of the helix is transferred to the dye aggregate. The dye does not interact with the free single-stranded DNA and although aggregating on the achiral PNA, this interaction is obviously not detectable by circular dichroism. Thus, only the formation of the PNA,DNA duplex, which takes place only upon specific Watson,Crick hydrogen binding between the PNA and the DNA bases, is detected, ensuring a very high specificity and sensitivity. The method has been optimized in a model system by using a synthetic oligonucleotide complementary to the PNA probe, showing that the intensity of the signal is linearly related to the amount of the DNA. The optimized method has been applied to the identification and quantitation of DNA extracted and amplified by PCR from peanuts and from peanut-containing foods, allowing for a very sensitive detection at a very low level (few pmol). © 2005 Wiley-Liss, Inc. Chirality 17:515,521, 2005. [source]

Multianalyte Electrochemical Biosensor Based on Aptamer- and Nanoparticle-Integrated Bio-Barcode Amplification

CHEMISTRY - AN ASIAN JOURNAL, Issue 2 2010
Xuemei Li Dr.
Abstract In the present work, a signal-on electrochemical sensing strategy for the simultaneous detection of adenosine and thrombin is developed based on switching structures of aptamers. An Au electrode as the sensing surface is modified with two kinds of thiolated capture probes complementary to the linker DNA that contains either an adenosine aptamer or thrombin aptamer. The capture probes hybridize with their corresponding linker DNA, which has prehybridized with the reporter DNA loaded onto the gold nanoparticles (AuNPs). The AuNP contained two kinds of bio-barcode DNA: one is complementary to the linker DNA (reporter), whereas the other is not (signal) and is tagged with different metal sulfide nanoparticles. Thus a "sandwich-type" sensing interface is fabricated for adenosine and thrombin. With the introduction of adenosine and thrombin, the aptamer parts bind with their targets and fold to form the complex structures. As a result, the bio-barcoded AuNPs are released into solution. The metal sulfide nanoparticles are measured by anodic stripping voltammetry (ASV), and the concentrations of adenosine and thrombin are proportional to the signal of either metal ion. With the dual amplification of the bio-barcoded AuNP and the preconcentration of metal ions through ASV technology, detection limits as low as 6.6×10,12,M for adenosine and 1.0×10,12,M for thrombin are achieved. The sensor exhibits excellent selectivity and detectability in biological samples. [source]