A simple quantitative chiral analysis of amino acid esters by fluorine‐19 nuclear magnetic resonance using the modified James–Bull method

A simple chiral analysis of amino acid esters by fluorine‐19 nuclear magnetic resonance (¹⁹F NMR) through the modified James–Bull method is described. Thus, amino acid ester acid salt was treated with 5‐fluoro‐2‐formylphenylboronic acid and (S)‐BINOL in the presence of triethylamine (TEA) and MS4A for 10 minutes. The reaction mixture was analysed by ¹⁹F NMR directly to afford good quantifications.     

新型冠状病毒的相关研究进展

2019年12月出现于湖北武汉的一种新型冠状病毒(SARS-CoV-2)感染所致肺炎疫情,给人类生命安全造成威胁。迄今为止,对2019年出现的SARS-CoV-2的研究仍处于起步阶段,本文就其相关研究进展进行综述,重点阐述了目前关于SARS-CoV-2的病原学与致病机制方面的研究成果,同时对其流行病学以及该病毒引发的肺炎临床特点加以总结,有助于读者及时了解SARS-CoV-2最新的研究动态,并为今后开展治疗药物及疫苗研发提供方向。     

Synthesis of sialyl Lewis<Superscript>a</Superscript> (sLe<Superscript>a</Superscript>, CA19-9) and construction of an immunogenic sLe<Superscript>a</Superscript> vaccine

Sialyl Lewis^a (sLe^a), also termed CA19-9 antigen, is recognized by murine mAb19-9 and is expressed on the cancer cell surface as a glycolipid and as an O-linked glycoprotein. It is highly expressed in a variety of gastrointestinal epithelial malignancies including colon cancer and pancreatic cancer, and in breast cancer and small cell lung cancer, but has a limited expression on normal tissues. sLe^a is known to be the ligand for endothelial cell selectins suggesting a role for sLe^a in cancer metastases and adhesion. For these reasons, sLe^a may be a good target for antibody mediated immunotherapy including monoclonal antibodies and tumor vaccines. However, sLe^a is structurally similar to sLe^x and other blood group related carbohydrates which are widely expressed on polymorphonucleocytes and other circulating cells, raising concern that immunization against sLe^a will induce antibodies reactive with these more widely expressed autoantigens. We have shown previously both in mice and in patients that conjugation of a variety of carbohydrate cancer antigen to keyhole limpet hemocyanin (KLH) and administration of this conjugate mixed with saponin adjuvants QS-21 or GPI-0100 are the most effective methods for induction of antibodies against these cancer antigens. We describe here for the first time the total synthesis of pentenyl glycoside of sLe^a hexasaccharide and its conjugation to KLH to construct a sLe^a-KLH conjugate. Groups of five mice were vaccinated subcutaneously four times over 6 weeks. Sera were tested against sLe^a-HSA by ELISA and against sLe^a positive human cell lines adenocarcinoma SW626 and small cell lung cancer (SCLC) DMS79 by FACS. As expected, mice immunized with unconjugated sLe^a plus GPI-0100 or unconjugated sLe^a mixed with KLH plus GPI-0100 failed to produce antibodies against sLe^a. However, mice immunized with sLe^a-KLH conjugate without GPI-0100 produced low levels of antibodies and mice immunized with sLe^a-KLH plus GPI-0100 produced significantly higher titer IgG and IgM antibodies against sLe^a by ELISA. These antibodies were highly reactive by FACS and mediated potent complement mediated cytotoxicity against sLe^a positive SW626 and DMS79 cells. They showed no detectable cross reactivity against a series of other blood group-related antigens, including Le^y, Le^x, and sLe^x by dot blot immune staining. This vaccine is ready for testing as an active immunotherapy for treating sLe^a positive cancer in clinical settings. Govind Ragupathi and Philip O. Livingston are paid consultants and shareholders in MabVax Therapeutics, Inc., San Diego, CA 92121. The sLe^a vaccine is licensed to MabVax.     

A Comprehensive Review of Animal Models for Coronaviruses: SARS-CoV-2, SARS-CoV,and MERS-CoV

The recent outbreak of coronavirus disease(COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has already affected a large population of the world. SARS-CoV-2 belongs to the same family of severe acute respiratory syndrome coronavirus(SARS-CoV) and Middle East respiratory syndrome coronavirus(MERSCoV). COVID-19 has a complex pathology involving severe acute respiratory infection, hyper-immune response, and coagulopathy. At present, there is no therapeutic drug or vaccine approved for the disease. There is an urgent need for an ideal animal model that can reflect clinical symptoms and underlying etiopathogenesis similar to COVID-19 patients which can be further used for evaluation of underlying mechanisms, potential vaccines, and therapeutic strategies. The current review provides a paramount insight into the available animal models of SARS-CoV-2, SARS-CoV, and MERS-CoV for the management of the diseases.     

SARS-CoV-2 cell receptor gene ACE2 -mediated immunomodulation in breast cancer subtypes

The recent outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has impacted the world severely. The binding of the SARS-CoV-2 virus to the angiotensin-converting enzyme 2 (ACE2) and its intake by the host cell is a necessary step for infection. ACE2 has garnered widespread therapeutic possibility as it is entry/interactive point for SARS-CoV-2, responsible for coronavirus disease 2019 (COVID-19) pandemic and providing a critical regulator for immune modulation in various disease. Patients with suffering from cancer always being on the verge of being immune compromised therefore gaining knowledge about how SARS-CoV-2 viruses affecting immune cells in human cancers will provides us new opportunities for preventing or treating virus-associated cancers. Despite COVID-19 pandemic got center stage at present time, however very little research being explores, which increase our knowledge in context with how SARS-CoV-2 infection affect cancer a cellular level. Therefore, in light of the ACE-2 as an important contributor of COVID-19 global, we analyzed correlation between ACE2 and tumor immune infiltration (TIL) level and the type markers of immune cells were investigated in breast cancer subtypes by using TIMER database. Our findings shed light on the immunomodulatory role of ACE2 in the luminal A subtype which may play crucial role in imparting therapeutic resistance in this cancer subtype.     

Oritavancin Binds to Isolated Protoplast Membranes but not Intact Protoplasts of Staphylococcus aureus

Solid-state NMR has been used to examine the binding of N′-4-[(4-fluorophenyl)benzyl)]chloroeremomycin, a fluorinated analogue of oritavancin, to isolated protoplast membranes and whole-cell sucrose-stabilized protoplasts of Staphylococcus aureus, grown in media containing [1-¹³C]glycine and l-[?-¹⁵N]lysine. Rotational-echo double-resonance NMR was used to characterize the binding by estimating internuclear distances from ¹⁹F of oritavancin to ¹³C and ¹⁵N labels of the membrane-associated peptidoglycan and to the ³¹P of the phospholipid bilayer of the membrane. In isolated protoplast membranes, both with and without 1 M sucrose added to the buffer, the nascent peptidoglycan was extended away from the membrane surface and the oritavancin hydrophobic side chain was buried deep in the exposed lipid bilayer. However, there was no N′-4-[(4-fluorophenyl)benzyl)]chloroeremomycin binding to intact sucrose-stabilized protoplasts, even though the drug bound normally to the cell walls of whole cells of S. aureus in the presence of 1 M sucrose. As shown by the proximity of peptidoglycan-bridge ¹³C labels to phosphate ³¹P, the nascent peptidoglycan of the intact protoplasts was confined to the membrane surface.     

Clinical features and hematological findings of COVID-19 patients with blood transfusion

This paper aims to illustrate the clinical characteristics, hematological findings, and blood transfusion information of Coronavirus disease 2019 (COVID-19) patients. Twenty-three COVID-19 patients were treated and transfused with blood products in Wuhan First Hospital from February 12 to March 20, 2020. The patients were divided into a survivor group and a non-survivor group, respectively, according to whether the patient had been discharged or died. The results demonstrated at the time of initial blood transfusion, that the non-survivor group possessed a lower platelet (PLT) than that of the survivor group (P<0.001), and PLT were below the normal range in 6 (85.7%) non-survivor group and in 2 (12.5%) survivor group (P<0.01). Over half of these patients had abnormalities in fibrinogen (FIB), activated partial thromboplastin time (APTT), prothrombin time (PT), and international normalized ratio (INR), but no significant difference was found between the non-survivor group and survivor group. The non-survivor group had a dramatically higher D-Dimers and disseminated intravascular coagulation (DIC) scores than those of the survivor group (P<0.01). Six (85.7%) non-survivors but none of the survivors had a DIC score greater than 6 (P<0.001). Fifteen (93.8%) survivors and 2 (28.6%) non-survivors were transfused with RBC (P<0.01). The non-survivors (5/7) possessed a higher proportion for using AP than the survivors (2/16). The study suggests that COVID-19 patients who undergo blood transfusion usually possess coagulation dysfunction, and DIC may be closely related to deteriorating clinical outcomes.     

Xanthophylls are preferentially taken up compared with beta-carotene by retinal cells via a SRBI-dependent mechanism

The purpose of this study was to investigate the mechanisms by which carotenoids [xanthophylls vs. beta-carotene(beta-C)] are taken up by retinal pigment epithelial (RPE) cells. The human RPE cell line, ARPE-19, was used. When ARPE-19 cells were fully differentiated (7-9 weeks), the xanthophylls lutein (LUT) and zeaxanthin (ZEA) were taken up by cells to an extent 2-fold higher than beta-C (P < 0.05). At 9 weeks, cellular uptakes were 1.6, 2.5, and 3.2%, respectively, for beta-C, LUT, and ZEA. Similar extents were observed when carotenoids were delivered in either Tween 40 or "chylomicrons" produced by Caco-2 cells. Differentiated ARPE-19 cells did not exhibit any detectable beta-C 15,15'-oxygenase activity or convert exogenous beta-C into vitamin A. When using specific antibodies against the lipid transporters cluster determinant 36 (CD36) and scavenger receptor class B type I (SR-BI), cellular uptake of beta-C and ZEA were significantly decreased (40-60%) with anti-SR-BI but not with anti-CD36. Small interfering RNA transfection for SR-BI led to marked knockdown of SR-BI protein expression (approximately 90%), which resulted in decreased beta-C and ZEA uptakes by 51% and 87%, respectively. Thus, the present data show that RPE cells preferentially take up xanthophylls versus the carotene by a process that appears to be entirely SR-BI-dependent for ZEA and partly so for beta-C. This mechanism may explain, in part, the preferential accumulation of xanthophylls in the macula of the retina.     

白斑综合症病毒囊膜蛋白VP19、VP28的融合表达及中和抗体的制备

根据GenBank上WSSV囊膜蛋白基因vp19和vp28的序列,设计并合成两对引物,PCR扩增得到vp19和vp28两基因,大小分别为370bp和630bp。通过EcoRI位点连接两基因,再按正确的阅读框插入表达载体pET-22b( )中,构建出重组表达载体pET-vp(19 28)并转化大肠杆菌BL21(DE3)。基因工程菌株35℃IPTG诱导,表达产物经SDS-PAGE检测显示有与预期大小41kDa相吻合的融合蛋白带。用Ni^2 -柱纯化的基因工程蛋白免疫新西兰大白兔制备抗血清,进行螯虾活体中和病毒实验,结果表明抗血清对WSSV的中和效率达到了100％。