Search

Single-cell transcriptomics is essential for understanding biological variability among cells in a heterogenous population. Acquiring high-quality single-cell sequencing data from a tissue sample has multiple challenges including isolation of individual cells as well as amplification of the genetic material. Commercially available techniques require the isolation of individual cells from a tissue through extensive manual manipulation before single cell sequence data can be acquired. However, since cells within a tissue have different dissociation constants, enzymatic and mechanical manipulation do not guarantee the isolation of a homogenous population of cells. To overcome this drawback, in this research we have developed a revolutionary approach that utilizes a fully automated nanopipette technology in combination with magnetic nanoparticles to obtain high quality sequencing reads from individual cells within an intact tissue thereby eliminating the need for manual manipulation and single cell isolation. With the proposed technology, it is possible to sample an individual cell within the tissue multiple times to obtain longitudinal information. Single-cell RNAseq was achieved by aspirating only1-5% of sub-single-cell RNA content from individual cells within fresh frozen tissue samples. As a proof of concept, aspiration was carried out from 22 cells within a breast cancer tissue slice using quartz nanopipettes. The mRNA from the aspirate was then selectively captured using magnetic nanoparticles. The RNAseq data from aspiration of 22 individual cells provided high alignment rates (80%) with 2 control tissue samples. The technology is exceptionally simple, quick and efficient as the entire cell targeting and aspiration process is fully automated.

Wilderness areas are important in maintaining biodiversity, and "retaining existing intact and wilderness areas" is listed as the first of 21 action targets for 2030 in the first draft of the post-2020 Global Biodiversity Framework. However, the quantity and quality of regional-scale wilderness mapping and identification of priority areas for conservation are still insufficient. Here, an approach integrating Boolean and Multi-Criteria Evaluation is used to conduct wilderness mapping, and priority conservation areas are identified based on ecosystem service values and the current status of wilderness protection in protected areas in the state-owned forest region of Daxing'anling. It is found that the wilderness areas account for 96.72% of the total area of the study area, of which high-quality wilderness areas constitute for 50.34% of the total area of wilderness areas, and the quality of wilderness is greatly affected by the railroads. Secondly, wilderness areas have higher ecosystem service values per square kilometer than non-wilderness areas, except for food supply service. In addition, 72.26% of the wilderness areas are not protected, and 52.26% of these high-quality wilderness areas with high ecosystem service values still have conservation gaps. This study can provide data support and scientific reference for future wilderness conservation works in different regions. [ABSTRACT FROM AUTHOR]

Alternaria tenuissima (Kunze) Wiltshire 1933 is a plant pathogenic fungus mainly causing leaf blotch disease. Here, we de novo assembled mitochondrial genome of A. tenuissima isolate AT-1224. The total mitogenome size is 57,475 bp with 29.00% G + C content. The genome contained 12 coding genes and 15 hypothetical proteins, 34 transfer RNA (tRNA) genes and 2 ribosomal RNA (rRNA). There are 227 SSR repeats, range from 2 to 4 base pairs, most five repeats were AT (144), AAT (54), AG (33), AC (13) and AAG (5). The results also found 13 tandem repeats (>100 bp), the largest repeat were forward 2 times located from 13,405 to 20,024 bp and 25,549 to 32,168 bp. Phylogenetic analysis based on 17 species complete mitogenomes indicated that A. tenuissima mitogenome was closest to 2 species, A. solani and A. alternata, sister clade to 6 species, representing Curvularia clavate, Exserohilum rostratum, Exserohilum turcicum, Bipolaris cookie, Bipolaris oryzae and Bipolaris sorokiniana. Further analysis among common fungus in local apple orchards using mitochondrial protein-coding genes revealed A. tenuissima were closing to 2 Alternaria fungi and a fungus representing Phoma sp. These results provide a basic reference for identification and evolution studies of A. tenuissima on apple trees. [ABSTRACT FROM AUTHOR]

In recent years, semiconductor nanocrystal quantum dots have garnered the spotlight as an important new class of biological labeling tool. With optical properties superior to conventional organic fluorophores from many aspects, such as high photostability and multiplexing capability, quantum dots have been applied in a variety of advanced imaging applications. This dissertation research goes along with large amount of research efforts in this field, while focusing on the design and development of new nanoprobes from semiconductor nanocrystals that are aimed for useful imaging or sensing applications not possible with quantum dots alone. Specifically speaking, two strategies have been applied. In one, we have taken advantage of the increasing capability of manipulating the shape of semiconductor nanocrystals by developing semiconductor quantum rods as fluorescent biological labels. In the other, we have assembled quantum dots and gold nanocrystals into discrete nanostructures using DNA. The background information and synthesis, surface manipulation, property characterization and applications of these new nanoprobes in a few biological experiments are detailed in the dissertation.

In recent years, semiconductor quantum dots have been applied with great advantage in a wide range of biological imaging applications. The continuing developments in the synthesis of nanoscale materials and specifically in the area of colloidal semiconductor nanocrystals have created an opportunity to generate a next generation of biological labels with complementary or in some cases enhanced properties compared to colloidal quantum dots. In this paper, we report the development of rod shaped semiconductor nanocrystals (quantum rods) as new fluorescent biological labels. We have engineered biocompatible quantum rods by surface silanization and have applied them for non-specific cell tracking as well as specific cellular targeting. The properties of quantum rods as demonstrated here are enhanced sensitivity and greater resistance for degradation as compared to quantum dots. Quantum rods have many potential applications as biological labels in situations where their properties offer advantages over quantum dots.

We report two cDNA microarray-based applications of DNA-nanocrystal conjugates, single-nucleotide polymorphism (SNP) and multiallele detections, using a commercial scanner and two sets of nanocrystals with orthogonal emissions. We focus on SNP mutation detection in the human p53 tumor suppressor gene, which has been found to be mutated in more than 50% of the known human cancers. DNA-nanocrystal conjugates are able to detect both SNP and single-base deletion at room temperature within minutes, with true-to-false signal ratios above 10. We also demonstrate microarray-based multiallele detection, using hybridization of multicolor nanocrystals conjugated to two sequences specific for the hepatitis B and hepatitis C virus, two common viral pathogens that inflict more than 10% of the population in the developing countries worldwide. The simultaneous detection of multiple genetic markers with microarrays and DNA-nanocrystal conjugates has no precedent and suggests the possibility of detecting an even greater number of bacterial or viral pathogens simultaneously.

A concept of emergence was introduced, and the optimization of system was carried out through reconstruction by utilizing the inherent logical relationship between system elements and architecture and the external expression of architecture and form, so as to equip system with more positive emergence instead of negative emergence. A concept of reconstruction pole was put forward, and the method of comprehensive evaluation across systems was established through the comparison of reconstruction pole elements, thus the problem of complex giant system optimization was broken. The integrated case of vibration isolation and anti-shock shows that system reconfiguration may bring great benefits, and "two in one" reconstruction model may have a wide application prospect in optimization design of complex systems such as naval vessels and airplanes, etc. [ABSTRACT FROM AUTHOR]

The results of magnetic susceptibility, isothermal magnetization, and heat capacity measurements on a newly discovered iron complex with mixed ligands Fe(N[sub 3])[sub 2](4,4'-bpy) (4,4'-bpy =4,4'-bipyridine) are reported. The study of high-temperature magnetic susceptibility data indicates antiferromagnetic correlation of the Fe[sup 2+] moments. However, the results of low-temperature measurements reveals a ferromagnetic transition for this compound, and the Curie temperature is determined from the Arrott plot with T[sub C] = 20 K. The large jump in the heat capacity data confirms the magnetic phase transition and the transition temperature. [ABSTRACT FROM AUTHOR]

Alternaria tenuissima (Kunze) Wiltshire 1933 is a plant pathogenic fungus mainly causing leaf blotch disease. Here, we de novo assembled mitochondrial genome of A. tenuissima isolate AT-1224. The total mitogenome size is 57,475 bp with 29.00% G + C content. The genome contained 12 coding genes and 15 hypothetical proteins, 34 transfer RNA (tRNA) genes and 2 ribosomal RNA (rRNA). There are 227 SSR repeats, range from 2 to 4 base pairs, most five repeats were AT (144), AAT (54), AG (33), AC (13) and AAG (5). The results also found 13 tandem repeats (>100 bp), the largest repeat were forward 2 times located from 13,405 to 20,024 bp and 25,549 to 32,168 bp. Phylogenetic analysis based on 17 species complete mitogenomes indicated that A. tenuissima mitogenome was closest to 2 species, A. solani and A. alternata, sister clade to 6 species, representing Curvularia clavate , Exserohilum rostratum , Exserohilum turcicum , Bipolaris cookie , Bipolaris oryzae and Bipolaris sorokiniana . Further analysis among common fungus in local apple orchards using mitochondrial protein-coding genes revealed A. tenuissima were closing to 2 Alternaria fungi and a fungus representing Phoma sp. These results provide a basic reference for identification and evolution studies of A. tenuissima on apple trees., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

In this paper, we report the development of rod-shaped semiconductor nanocrystals (quantum rods) as fluorescent biological labels. Water-soluble biocompatible quantum rods have been prepared by surface silanization and applied for nonspecific cell tracking as well as specific cellular targeting. Quantum rods are brighter single molecule probes as compared to quantum dots. They have many potential applications as biological labels in situations where their properties offer advantages over quantum dots.

Objective: To evaluate the role played by mesolimbic dopaminergic system in the reinstatement of drug-seeking behavior induced by priming injections of morphine., Methods: After the extinguishment of morphine conditioned place preference (CPP), low-dose catecholaminergic neurotoxin 6-hydroxydopamine (6-OHDA) was bilaterally injected into ventral tegmental area (VTA, 1 g.L-1) and nucleus accumbens (NAc, 5 g.L-1) before being primed with low-dose morphine., Results: The effects of drug-priming to induce reinstatement of morphine CPP could be completely abolished by 6-OHDA microinjected into VTA to damage the perikaryon of dopaminergic neurons, or into NAc to lesion the terminal field of the dopaminergic pathway., Conclusion: The functional integrality of the mesolimbic dopaminergic system is indispensable for drug priming-induced reinstatement of conditioned place preference.