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Linear chromatin is compacted into eukaryotic nucleus through a complex and multi-layered architecture. Consequently, chromatin conformation in a local or long-distance manner is strongly correlated with gene expression. Chromosome conformation capture (3C) technology, together with its variants like 4C/5C/Hi-C, has been well developed to study chromatin looping and whole genome structure. In this review, we introduce new technologies including chromosome capture combined with immunoprecipitation, nuclei acid-based hybridization, single cell and genome sequencing, as well as their application.
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Núcleo Celular , Cromatina/genética , Cromossomos/genética , Técnicas Genéticas , Genoma/genéticaRESUMO
Objective To evaluate the effect of adenosine receptor antagonist SCH442416 on the expression of Kir2.1,Kir4.1 and TASK-1 in rat Müller cell at an elevated hydrostatic pressure in vitro.Methods Thirty SPF Sprague Dawley rats were purchased from Shanghai Slack Laboratory Animals Ltd.Cultured Müller cells were divided into normal control group (n =6),40 mmHg/24 hours (1 mmHg =0.133 kPa) group (n =6) and adenosine + SCH442416 intervention group (n =6).Müller cells were treated with 40 mmHg pressure for 24 hours in 40 mmHg/24 hours group,and Müller cells were treated with 40 mmHg pressure for 24 hours + 10 μ mol/L adenosine + 100 nmol/L SCH442416 in adenosine + SCH442416 intervention group.The real-time PCR,Western blot,whole-cell patch-clamp recordings and immunohistochemistry were used to detect Kir2.1,Kir4.1 and TASK-1 expression and Müller cells Kir currents.The experimental procedures were in accordance with the National Institutes of Health (NIH) guidelines for the Care and Use of Laboratory,and follow the 3R principle.Results Western blot assay showed that,following 40 mmHg pressure cultured for 24 hours,the expression of Kir4.1 and TASK-1 protein in Müller cell were significantly decreased by 38.6％ and 52.6％ compared with the normal control group,with significant differences between the two groups (both at P =0.000);Kir2.1 protein expression decreased by 14.7％,with insignificant difference between the two groups (P =0.082).Kir4.1 and TASK protein expression in adenosine + SCH442416 intervention group was increased by 60.7％ and 61.4％ compared with the 40 mmHg/24 hours group,with significant differences between the two groups (both at P =0.000);Kir2.1 protein expression in adenosine + SCH442416 intervention group was increased by 8.8％ compared with the 40 mmHg/24 hours group,with insignificant difference between them (P =0.354).Real-time PCR assay showed that,following 40 mmHg pressure cultured for 24 hours,Kir2.1,Kir4.1 and TASK-1 mRNA expression in Müller cells were significantly decreased compared with the normal control group,with significant differences between the two groups (P =0.047,0.001,0.000);Kir4.1 and TASK-1 mRNA expression in Müller cells in the adenosine + SCH442416 intervention group was significantly increased compared with the 40 mmHg/24 hours group,with significant differences between the two groups (P =0.038,0.030);however,there is no significant change in Kir2.1 mRNA expression (P =0.612).Conclusions SCH442416 upregulates the expression of Kir4.1 and TASK-1 mRNA and protein,but weakly affects the expression of Kir2.1.
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Objective To evaluate the effects of two different chronic glaucoma models on intraocular pressure elevation and retinal structure changes in rat.Methods Two different chronic ocular hypertension (COH) models were made by three episcleral vein cauterization or latex microspheres injection into anterior chamber,6 cases of each model.IOP measurements of right eyes (COH eye) and left eye (control eye) were taken weekly by TonoPen (an applanation tonometer).Retinal ganglion cells (RGCs) were retrogradely labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) seven weeks later.Retina structure was observed by immunofluorescence.Results IOP was elevated at postoperative 1-8 weeks,and the mean IOP in the episcleral vein cauterization group was (27.20 ± 1.83) mmHg (1 kPa =7.5 mmHg),whereas the control group was (19.80 ± 1.35) mmHg (P =0.001,n =6).The mean IOP in the latex microspheres injection group was (27.40 ± 1.88) mmHg,whereas the control group was (19.40 ± 1.00) mmHg (P =0.000,n =6).Compared with control rat at postoperative 8 weeks,RGCs loss in episcleral vein cauterization group were 37.9％,39.6 and 33.5％ (all P =0.000,n =6),latex microspheres injection group were 37.3％,39.4％ and 33.5％ (all P =0.000,n =6).There was no statistical difference between episcleral vein cauterization group and latex microspheres injection group (P =0.855,0.949,0.634,n =6).Compared with control rat at postoperative 8 weeks,GCL thickness in both COH models were also significant reduced,but there was no statistical difference in GCL thickness among control group (7.32 ± 0.39) μm,episcleral vein cauterization group (4.97 ±0.33) μm,latex microspheres injection group (5.00 ±0.31) μm.Misoperation or careless operation may lead to microspheres particle residual on flat-mounted rat retina.Conclusion The episcleral vein cauterization or latex microspheres injection into anterior chamber can all increase the IOP.However,there are some advantages in episcleral vein cauterization such as few costs than latex microspheres injection and no microsphere contamination.
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Objective There are three categories of bioaerosol laser telemetry systems according to the light source configuration parameters:namely traditional lidar(light datection and ranging,laser radar), micro-pulse lidar and pseudo-random modulation(lidar).The system source parameters,which impact the degree of danger and detection sensitivity of the system, need to be optimized.Methods With reference to the USA laser product safety standards and by establishing the corresponding mathematical model of a lidar, the three categories of lidar source configuration were compared according to signal to noise ratio(SNR) and security before the repetition rate, pulse energy, divergence angle, distance and other dangerous impact factors were calculated.Results The results showed that to ensure eyesafety, the use of the pulse frequency should be set at 55 kHz for the highest SNR under the micro-pulse lidar excitation mode.Conclusion The eyesafety requirements impact the excitation of light source of a bioaerosol telemetry system.
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Objective To develop a multi-channel dry type biochemistry sensor with a compact structure and high measurement accuracy.Methods The principle of double beam compensation based on reference LED was applied to improve the measurement accuracy.The complex splitting system was replaced by MXN fiber bundle and free-form surface lens to make the instrument more compact and lightweight.Use of the adaptive amplification photoelectric detection improved the measurement accuracy while simplifying the process.Results and Conclusion It has been proved by experiments that this sensor has the advantages of high measurement accuracy, little interference and compact construction. This sensor may well meet the requirements of dry type biochemistry analysis.
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Technology for rapid detection of trace microbes combined with flow cytometry and image cytometry is used for rapid detection of cells and microorganisms, quantification of fluorescent signals, and visualization of cells and mi-crobes.Its fast and accurate count of microorganisms plays an important role in detection of the quantity of food and water, and can help to improve residents′quality of life and health.This article describes several common methods for detecting microorganisms with emphasis on their advantages and disadvantages.Current applications and future developlments are also discussed.