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排序方式: 共有259条查询结果,搜索用时 15 毫秒
1.
目的:探讨混合甲醛固定液固定大肠癌淋巴结标本的最佳免疫组化效果。方法:采用不同pH值(6.0、7.0、8.0)的混合甲醛固定液对39枚大肠癌淋巴结标本进行不同时间(6 h、6 h-12 h、1 d-7 d)的固定处理。以细胞角蛋白20(CK20)为目标抗原,运用OIympusdp 70图像采集分析仪抽选出混合甲醛固定液最佳免疫组化染色的pH值及固定时间。结果:经pH值为7.0混合甲醛固定液处理后,阳性率为92.31%,高于经pH值为6.0、8.0的混合甲醛固定液处理后的76.92%、74.36%,且经pH值为7.0、8.0处理后的阳性率比较有统计差异(P0.05)。混合甲醛固定液的固定时间在6 h-12 h时的阳性率为94.87%,高于固定时间为6 h、1 d-7 d处理的30.77%、76.92%(P0.05)。结论:对于大肠癌淋巴结标本,以CK20为目标抗原,选择pH值为7.0的混合甲醛固定液固定6 h-12 h能够得到质量较佳的免疫组化染色效果。 相似文献
2.
Tom van der Valk Francesco Vezzi Mattias Ormestad Love Daln Katerina Guschanski 《Molecular ecology resources》2020,20(5):1171-1181
The high‐throughput capacities of the Illumina sequencing platforms and the possibility to label samples individually have encouraged wide use of sample multiplexing. However, this practice results in read misassignment (usually <1%) across samples sequenced on the same lane. Alarmingly high rates of read misassignment of up to 10% were reported for lllumina sequencing machines with exclusion amplification chemistry. This may make use of these platforms prohibitive, particularly in studies that rely on low‐quantity and low‐quality samples, such as historical and archaeological specimens. Here, we use barcodes, short sequences that are ligated to both ends of the DNA insert, to directly quantify the rate of index hopping in 100‐year old museum‐preserved gorilla (Gorilla beringei) samples. Correcting for multiple sources of noise, we identify on average 0.470% of reads containing a hopped index. We show that sample‐specific quantity of misassigned reads depends on the number of reads that any given sample contributes to the total sequencing pool, so that samples with few sequenced reads receive the greatest proportion of misassigned reads. This particularly affects ancient DNA samples, as these frequently differ in their DNA quantity and endogenous content. Through simulations we show that even low rates of index hopping, as reported here, can lead to biases in ancient DNA studies when multiplexing samples with vastly different quantities of endogenous material. 相似文献
3.
InthecourseofpreparingatreatmentoftheAquifoliaceaeforFloraReipublicaePopularisSinicae,wefoundthatvalidpublicationofeightname... 相似文献
4.
Three species of the arcto-boreal, large gastropod Neptunea , described by Linnaeus in 1758 and 1771, occur in large numbers over wide areas of the inshore North Atlantic and adjacent Arctic seas and are conspicuous among Pliocene and Pleistocene molluscs in the Icelandic, North Sea, and western Mediterranean basins. Selections of lectotypes for these species from shells in the collection of the Linnean Society of London, and designations of their type localities, establish the identity of Linnaeus' neptunes and more accurately determine their geographic and geologic distribution. The geographic range of Neptunea (Neptunea) antiqua (L.), the type species, now extends from southern Norway to the northern Biscay coast of France and from the westernmost Baltic Sea to southwestern Ireland; this species also occurs in Pliocene-Holocene marine deposits in West and East Germany, Sweden, the Netherlands, England and France. Its type locality is determined to be the North Sea. N. (Neptunea) despecta (L.) lives in the eastern Canadian Arctic, off southern Greenland, the Barents Sea, and North Atlantic as far south as Massachusetts and Portugal; it also occurs in Pliocene-Holocene strata of eastern Canada, east-central Greenland, Norway (including Svalbard), the Soviet Union, Sweden and England. Its type locality is determined to be the postglacial deposits at Uddevalla in southwestern Sweden. N. (Sulcosipho) contraria (L.) now extends from the southern Biscay coast of France to Cape Spartel, Morocco; this species also occurs in Pleistocene and lower Holocene sequences of the western Mediterranean. Its type locality is determined to be Vigo Bay, Spain. A closely related fossil species, N. (S.) angulata (S. V. Wood), occurs in Pliocene and Pleistocene deposits of the North Sea basin. 相似文献
5.
Ready-to-use DNA extracted with a CTAB method adapted for herbarium specimens and mucilaginous plant tissue 总被引:2,自引:0,他引:2
J. Hugo Cota-Sánchez Kirsten Remarchuk Kumary Ubayasena 《Plant Molecular Biology Reporter》2006,24(2):161-167
This report summarizes major changes in previously published protocols for DNA extraction to improve the quality of DNA extracted
from plants. Here, we highlight the critical modifications in the original protocols. The efficiency of these changes results
in high-quality DNA ready to use in a variety of phytogenetically distant plant families, in particular species with mucopolysaccharides.
The DNA obtained can be used without further purification in various molecular biology assays, including direct sequencing
and AFLP and RAPD (random-amplified polymorphic DNA) analyses. The effectiveness of this method is proven by the amplification
and sequencing of PCR products of up to 1 kb with DNA extracted from herbarium tissue ≥60 years old. This versatility is not
usually found in DNA extraction protocols. In addition, this method is quick, adaptable to standard laboratories, and most
important, safer and more cost-effective. 相似文献
6.
7.
Trace Akankunda Hien To Carlos Rodriguez Lopez Remko Leijs Katja Hogendoorn 《Molecular ecology resources》2020,20(3):692-705
For molecular insect identification, amplicon sequencing methods are recommended because they offer a cost‐effective approach for targeting small sets of informative genes from multiple samples. In this context, high‐throughput multilocus amplicon sequencing has been achieved using the MiSeq Illumina sequencing platform. However, this approach generates short gene fragments of <500 bp, which then have to be overlapped using bioinformatics to achieve longer sequence lengths. This increases the risk of generating chimeric sequences or leads to the formation of incomplete loci. Here, we propose a modified nested amplicon sequencing method for targeting multiple loci from pinned insect specimens using the MiSeq Illumina platform. The modification exists in using a three‐step nested PCR approach targeting near full‐length loci in the initial PCR and subsequently amplifying short fragments of between 300 and 350 bp for high‐throughput sequencing using Illumina chemistry. Using this method, we generated 407 sequences of three loci from 86% of all the specimens sequenced. Out of 103 pinned bee specimens of replicated species, 71% passed the 95% sequence similarity threshold between species replicates. This method worked best for pinned specimens aged between 0 and 5 years, with a limit of 10 years for pinned and 14 years for ethanol‐preserved specimens. Hence, our method overcomes some of the challenges of amplicon sequencing using short read next generation sequencing and improves the possibility of creating high‐quality multilocus barcodes from insect collections. 相似文献
8.
The peregrine falcon (Falco peregrinus) population in southern Scandinavia was almost extinct in the 1970’s. A successful reintroduction project was launched in
1974, using captive breeding birds of northern and southern Scandinavian, Finnish and Scottish origin. We examined the genetic
structure in the pre-bottleneck population using eleven microsatellite markers and compared the data with the previously genotyped
captive breeding population and contemporary wild population. Museum specimens between 53 and 130 years old were analyzed.
Despite an apparent loss of historical genetic diversity, the contemporary population shows a relatively high level of genetic
variation. Considerable gene introgression from captive breeding stock used to repopulate the former range of southern Scandinavian
peregrines may have altered the genetic composition of this population. Both the historical and contemporary northern and
southern Scandinavian populations are genetically differentiated. The reintroduction project implemented in the region and
the use of non-native genetic stock likely prevented the southern Scandinavian population from extinction and thus helped
maintain the level of genetic diversity and prevent inbreeding depression. The population is rapidly increasing in numbers
and range and shows no indication of reduced fitness or adaptive capabilities in the wake of the severe bottleneck and the
reintroduction. 相似文献
9.
H. C. Rosenbaum M. G. Egan P. J. Clapham R. L. BrownellJr & R. DeSalle 《Molecular ecology》1997,6(7):677-681
DNA was isolated from an early twentieth century museum specimen of northern right whale baleen. A system of stringent controls and a novel set of cetacean specific primers eliminated contamination from external sources and ensured the authenticity of the results. Sequence analysis revealed that there were informative nucleotide positions between the museum specimen and extant members of the population and closely related species. The results indicate that museum specimens of baleen can be used to assess historical genetic population structure of the great whales. 相似文献
10.
T. C. Pan C. J. Horng S. R. Lin T. H. Lin C. W. Huang 《Biological trace element research》1993,38(3):233-241
Blackfoot disease (BFD) is an endemic peripheral vascular disorder resulting in gangrene of the lower extremities, especially the feet, among residents in a limited area on the southwest coast of Taiwan. In the present study, the concentrations of zinc, cadmium, lead, and copper in urine of BFD patients with matched normal controls are investigated by differential pulse anodic stripping voltammetry (DPASV) on a hanging mercury drop electrode (HMDE). The analytical results indicate that urinary copper, cadmium, and lead of the BFD patients are significantly higher than those of the controls. In addition, the patients showed a significantly lower concentration of zinc in the urine than the normal controls. The possible connection of these elements with the etiology of the disease is discussed. 相似文献