Analysis and Design of Fiber Microprobe Displacement Sensors Including Collimated Type and Convergent Type for Ultra-Precision Displacement Measurement.

In this paper, a fiber optic microprobe displacement sensor is proposed considering characteristics of micro-Michelson interference structure and its components. The principal error of micro Fabry-Perot interferometric structure is avoided, and high-precision interferometric displacement measurement is realized. The collimated microprobe and convergent microprobe are analyzed, simulated, and designed for the purposes of measuring long-distance displacement and small spot rough surface, respectively. The core parameters of the probes' internal components are mapped to coupling efficiency and contrast of the sensor measurements, which provides a basis for the probes' design. Finally, simulation and experimental testing of the two probes show that the collimated probe's working distance and converging probe's tolerance angle can reach 40 cm and ±0.5°, respectively. The designed probes are installed in the fiber laser interferometer, and a displacement resolution of 0.4 nm is achieved.

Complete plastome sequence of Dracaena cambodiana (Asparagaceae): a species considered "Vulnerable" in Southeast Asia.

Dracaena cambodiana (Asparagaceae) is a treelike plant ranging from 3 to 10 m tall. It grows in low-elevation forests (0-300 m) having dry and sandy soils. It is distributed in Southern Hainan Island in China and other Southeast Asian countries (e.g. Cambodia, Laos, Thailand and Vietnam). The dried resin can be used medicinally as a substitute for that of Dracaena cochinchinensis. It has been ranked as a Vulnerable (VU) species in China. Here we report and characterize the complete plastid genome sequence of D. cambodiana. The complete plastome is 156,697 bp in length. It contains the typical structure and gene content of angiosperm plastomes, including two Inverted Repeat (IR) regions of 26,526 bp, a Large Single-Copy (LSC) region of 84,988 bp and a Small Single-Copy (SSC) region of 18,657 bp. The plastome contains 113 genes, consisting of 76 unique protein-coding genes, 30 unique tRNA genes, four unique rRNA genes and three pseudogenes (i.e. matK, infA, ndhF). The overall A/T content in the plastome of D. cambodiana is 62.4%. We performed phylogenetic analyses using the entire plastome, including spacers, introns, etc., and we determined that D. cambodiana and Maianthemum bicolor were closely related. The complete plastome sequence of D. cambodiana will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Asparagales.

Effective gene editing by high-fidelity base editor 2 in mouse zygotes.

Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease-causing mutations in patients. However, problems such as mosaicism and low mutagenesis efficiency continue to pose challenges to clinical application of such approaches. Recently, a base editor (BE) system built on cytidine (C) deaminase and CRISPR/Cas9 technology was developed as an alternative method for targeted point mutagenesis in plant, yeast, and human cells. Base editors convert C in the deamination window to thymidine (T) efficiently, however, it remains unclear whether targeted base editing in mouse embryos is feasible. In this report, we generated a modified high-fidelity version of base editor 2 (HF2-BE2), and investigated its base editing efficacy in mouse embryos. We found that HF2-BE2 could convert C to T efficiently, with up to 100% biallelic mutation efficiency in mouse embryos. Unlike BE3, HF2-BE2 could convert C to T on both the target and non-target strand, expanding the editing scope of base editors. Surprisingly, we found HF2-BE2 could also deaminate C that was proximal to the gRNA-binding region. Taken together, our work demonstrates the feasibility of generating point mutations in mouse by base editing, and underscores the need to carefully optimize base editing systems in order to eliminate proximal-site deamination.

Efficient Production of Gene-Modified Mice using Staphylococcus aureus Cas9.

The CRISPR/Cas system is an efficient genome-editing tool to modify genes in mouse zygotes. However, only the Streptococcus pyogenes Cas9 (SpCas9) has been systematically tested for generating gene-modified mice. The protospacer adjacent motif (PAM, 5'-NGG-3') recognized by SpCas9 limits the number of potential target sites for this system. Staphylococcus aureus Cas9 (SaCas9), with its smaller size and unique PAM (5'-NNGRRT-3') preferences, presents an alternative for genome editing in zygotes. Here, we showed that SaCas9 could efficiently and specifically edit the X-linked gene Slx2 and the autosomal gene Zp1 in mouse zygotes. SaCas9-mediated disruption of the tyrosinase (Tyr) gene led to C57BL/6J mice with mosaic coat color. Furthermore, multiplex targeting proved efficient multiple genes disruption when we co-injected gRNAs targeting Slx2, Zp1, and Tyr together with SaCas9 mRNA. We were also able to insert a Flag tag at the C-terminus of histone H1c, when a Flag-encoding single-stranded DNA oligo was co-introduced into mouse zygotes with SaCas9 mRNA and the gRNA. These results indicate that SaCas9 can specifically cleave the target gene locus, leading to successful gene knock-out and precise knock-in in mouse zygotes, and highlight the potential of using SaCas9 for genome editing in preimplantation embryos and producing gene-modified animal models.

Elevated Serum Level of Angiopoietin-2 as a Potential Marker for Poor Prognosis in Small Cell Lung Cancer.

Small cell lung cancer (SCLC) is a fast-growing cancer with poor prognosis. Patients with extensive-stage SCLC are generally treated with chemotherapy. Thus, it is essential to identify a predictor of efficacy and prognosis for SCLC. Angiopoietin-2 promotes vascular remodeling and angiogenesis. Increasing evidence reveals that angiopoietin-2 is preferentially expressed in cancer cells, and elevated angiopoietin-2 expression is related to invasive and metastatic phenotypes in various cancers. However, serum angiopoietin-2 level and its prognostic potential in SCLC have not been investigated. The aim of this study was to determine the usefulness of angiopoietin-2 level as a predictor of efficacy and prognosis for SCLC. This study consisted of sixty patients with SCLC. Each patient received four cycles of cisplatin-etoposide chemotherapy, and was followed for 36 months. Serum angiopoietin-2 levels were measured by Enzyme-linked immunosorbent assays. The angiopoietin-2 levels were significantly higher in SCLC patients than those in healthy subjects (P < 0.001). The patients were divided into high-level group (32 patients, 2,923.9 ± 294.7 pg/ml) and low-level group (28 patients, 1,789.5 ± 355.1 pg/ml) according to the mean value of the angiopoietin-2 level (2,400 pg/ml). Compared with the patients in the high-level group, the patients in the low-level group showed remarkably survival advantage (P = 0.002). During chemotherapy, the patients in the low-level group showed better treatment response than the patients in the high-level group (P < 0.05). Therefore, angiopoietin-2 might be useful as a prognostic factor for SCLC and for predicting SCLC response to chemotherapy.

MiRNA-218, a new regulator of HMGB1, suppresses cell migration and invasion in non-small cell lung cancer.

MicroRNAs (miRNAs) function as negative regulators of gene expression involved in cancer metastasis. The aim of this study is to investigate the potential roles of miR-218 in non-small cell lung cancer and validate its regulation mechanism. Functional studies showed that miR-218 overexpression inhibited cell migration and invasion, but had no effect on cell viability. Enhanced green fluorescent protein reporter assay, real-time polymerase chain reaction and western blot analysis confirmed that miR-218 suppressed the expression of high mobility group box-1 (HMGB1) by directly targeting its 3'-untranslated region. Accordingly, silencing of HMGB1 accorded with the effects of miR-218 on cell migration and invasion, and overexpression of HMGB1 can restore cell migration and invasion which were reduced by miR-218. In conclusion, these findings demonstrate that miR-218 functions as a tumor suppressor in lung cancer. Furthermore, miR-218 may act as a potential therapeutic biomarker for metastatic lung cancer patients.