Chromosomal Localization of Genes bz1,bz2 in Maize by Using Ultra-sensitive FISH with Tyramide Signal Amplification(TSA-FISH)

It has been reported that endosperm undergoes programmed cell death (PCD) during maize kernel development.Both bz1 (bronze ) and bz2 are anthocyanin biosynthetic genes,and related to development of aleuronic layer of maize seeds.Tyramide signal amplification fluorescence in situ hybridization (TSA FISH) is a novel and high sensitive FISH technique,which is suitable for routine application in plant cytogenetic research.Using this technique,we physically mapped the bz1 gene onto the short arm of chromosome 9 and the long arm of chromosome 1;the percentage distances from centromere to hybridization site were 40.2,75.4 respectively,and the bz2 onto the long arm of chromosome 1 and the short arm of chromosome 5;the percentage distances from centromere to hybridization site were 21.6,15.3 separately.The TSA FISH techniques of small low copy DNA sequences for plants are discussed.

Ultrasensitive detection of cancer biomarker microRNA by amplification of fluorescence of lanthanide nanoprobes

Sensitive detection of cancer biomarker microRNAs （miRNAs） is of vital importance for cancer diagnosis and treatment. Nonetheless, the detection sensitivity in the existing miRNA bioassays is severely limited by the structural characteristics of miRNA （including small length and high sequence homology） because most of these methods are based on target amplification. Herein, we report a novel approach to sensitive and specific detection of low-abundance miRNA via a unique strategy of nanoprobe dissolution-enhanced fluorescence amplification, in which a capture probe featuring molecular beacon structure is designed. By means of this strategy, miRNA-21 was detected in a linear range from 10 fM to 100 pM with a detection limit as low as 1.38 fM. High selectivity of the newly developed biosensor was demonstrated by the good discrimination against a target with a single-base mismatch. Furthermore, this assay was used for the detection of miRNA-21 added into fetal bovine serum samples with the recovery in the range of 90.2%--108% and coefficients of variation below 10.1%, indicating its promising applications to RNA immunoassays and early cancer diagnosis.

Amidinium sulfonate hydrogen-bonded organic framework with fluorescence amplification function for sensitive aniline detection

Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.

Amplified fluorescence of Mg^2+ selective red-light emitting carbon dot in water and direct evaluation of creatine kinase activity

Carbon quantum dot/carbon dot(CD)exhibiting sustained photoluminescence at longer wavelengths in aqueous solution is difficult to prepare,but has enormous potential in biomedical applications.For the first time,we report the magnesium(II)selective fluorescence enhancement of a red-light emitting anthrarufin and boric acid-derived CD in aqueous solution for direct evaluation of creatine kinase(CK)enzyme activity.The CD displayed visually detectable,intense red fluorescence only in the presence of magnesium ion(Mg^2+)at physiological pH value when irradiated with an ultraviolet(UV)source.Concurrently,a significant increase in steady-state fluorescence intensity and fluorescence lifetime was documented.A time-dependent density functional theory(TD-DFT)analysis displayed a bathochromic shift in UV–visible(vis)absorption,and increased oscillator strength of transition resulting from the selective chelation of Mg^2+withβ-hydroxy keto functionality on the surface of the CD.The CD–Mg^2+assembly was subsequently used to conceptualize the detection of CK directly through the exploration of the differential binding affinity of Mg2+with adenosine triphosphate(ATP),adenosine diphophate(ADP),and CD that is otherwise not possible with commercially available kits as of today.Thus,the report delineated here usher grandeur potential of CD for biological explorations related to Mg2+or ATP sensing and monitoring of Mg^2+-dependent enzymatic activity through a clear understanding of the chemistry.

Magnetic covalent organic framework nanospheres-based miRNA biosensor for sensitive glioma detection

Sensitive detection and accurate diagnosis/prognosis of glioma remain urgent challenges.Herein,dispersed magnetic covalent organic framework nanospheres(MCOF)with uniformed Fe3O4 nano-assembly as cores and high-crystalline COF as shells were prepared by monomer-mediated in-situ interface growth strategy.Based on the unique interaction between MCOF and hairpin DNA,a fluorescent signal amplified miRNA biosensor was constructed.It could realize the sensitive detection of miRNA-182 in different matrixes,where the detection limit,linearity range and determination coefficient(R^(2))in real blood samples reached 20 fM,0.1 pM-10 pM and 0.991,respectively.Also,it possessed good stability and precision as observed from the low intra-day/inter-day RSD and high extraction recovery.As a result,it could quantify miRNA-182 in serum of glioma patients,the concentration of which was significantly higher than that of healthy people and obviously decreased after surgery.Finally,a proof-of-concept capillary chip system using this biosensor was proposed to realize the visualized detection of miRNA-182 in microsample.These findings suggest a robust way for sensitive detection and accurate diagnosis/prognosis of glioma.

Express and sensitive detection of multiple miRNAs via DNA cascade reactors functionalized photonic crystal array

Array based detection techniques with fluorescence signal reading is a powerful tool for multiple targets analysis. However,when applied fluorescence array for micro RNA detection, time-consuming multi-steps surface signal amplification is usually required due to the low abundance of micro RNA in total RNA expressions, which impairs detection efficiency and limits its application in point of care test(POCT) manner. Herein, DNA cascade reactors(DCRs) functionalized photonic crystal(PC)array was fabricated for express and sensitive detections of mi RNA-21 and mi RNA-155. DCRs were assembled by interval conjugation of self-quenched hairpin DNA probes to single strand DNA nanowire synthesized by rolling circle amplification,which generated cascade DNA hybridization reactions in response to target mi RNAwith instant fluorescence recovery signal. PC array patterns with multi-structure colors further amplified fluorescence with their respective photonic bandgaps(PBGs)matching with the emission peaks of fluorescence molecules labelled on DCRs. The as-prepared DCRs functionalized PC array demonstrated express and sensitive simultaneous detections of mi RNA-21 and mi RNA-155 with hundreds f M detection limits only in 15 min, and was successfully applied in fast quantifications of low abundance mi RNAs from cell lysates and spiked mi RNAs from human serum, which would hold great potential for disease diagnosis and therapeutic effect monitoring with a POCT manner.