螺旋藻多糖抗肿瘤作用的实验研究

报道了从钝顶螺旋藻中提取的一种水溶性多糖类化合物，即钝顶螺旋藻多糖(PSP)抗肿瘤作用的实验研究。体外实验结果表明，随PSP浓度增加，肿瘤细胞存活率逐渐降低，抑制率逐渐增加。体内实验，结果显示，PSP在50～200mg/kg的剂量范围对小鼠S-180肉瘤，均有一定的抑制作用。提示PSP可通过全面调节机体的免疫功能，刺激T细胞、NK细胞等功能来达到控制和杀灭肿瘤细胞的目的。     

胸腺素α1基因在钝顶螺旋藻中的表达

将钝顶螺旋藻（Spirulina platensis）在24℃培养，并经2mmol/L EDTA预处理16－24h，以本实验室构建的基因整合平台系统供体质粒pEUTISI进行超声波转化螺旋藻，经筛选获得了具G418抗性的转化藻株。通过PCR扩增和Southern杂交证实，pEUTISI中目的的基因UB－Tα1和nptII基因已整合到钝顶螺旋藻染色体上。转化藻株经45℃热诱导40min后，进行蛋白质SDS－PAGE电泳和Western blot，杂交结果证实，外源胸腺素α1基因在螺旋藻中得到有效表达。     

藻蓝蛋白对Hela细胞CD59基因表达调控作用的研究

探讨了钝顶螺旋藻藻蓝蛋白(PC)对Hela细胞CD59基因表达的调控作用.以正常人CD59cDNA基因为模板,经PCR扩增后重组入真核表达质粒载体pALTER-MAX,然后利用阳离子脂质体(Lipfectamine-2000)将重组质粒和PcDNA共转染人子宫颈癌细胞(Hela)和对照用正常中国仓鼠卵巢细胞(Chinese hamster ovary,CHO)进行表达.用不同浓度的钝顶螺旋藻藻蓝蛋白作用于转染细胞,通过核酸分子杂交技术、免疫荧光标记法和ELISA法对细胞中CD59分子的表达进行检测.结果表明:成功构建了重组质粒pALTER-MAX-CD59,并将其导入真核细胞(Hela,CHO),经G418筛选获得了CD59分子高效表达的细胞克隆.用藻蓝蛋白作用于筛选出的转基因细胞,证实藻蓝蛋白可促进Hela细胞表面CD59蛋白的表达并抑制Hela细胞的增殖,而对于正常CHO细胞无明显作用.     

牙鲆淋巴囊肿病毒在牙鲆鳃细胞系FG-9307中的增殖

向已建立的牙鲆（Paralichthys olivaceus）鳃细胞系^[1](FG-9307)中接种淋巴囊肿病（Lymphocystis disease virus,LCDV）、探讨其是否可支持LCDV的增殖。光学显微镜观察发现：接种3天后，呈纤维状的鳃细胞隆起、立体感加强；之后细胞逐渐变圆，一周左右绝大部分鳃细胞变圆、呈现了细胞病变（cytopathic effect,CPE）现象。将CPE细胞制作超薄切片，电镜观察发现细胞内有大量具囊膜、直径133－186nm的LCDV。CPE细胞的核变形、线粒体增加且空洞化，出现了与淋巴囊肿细胞相同的特征。本实验证明：FG－9307是可持续LCDV增殖的鱼类细胞系。     

螺旋藻对六种抗生素的敏感性研究

通过6种基因工程中常用抗生素对螺旋藻生长抑制的研究发现,钝顶螺旋藻S6和极大螺旋藻SM对卡那霉素和新霉素不敏感,10－700μg/ml的卡那霉素和10－300μg/ml新霉素仍不能抑制其生长;S6和SM对庆大霉素的敏感性存在较大差异,液体培养中的抑制浓度分别是300μg/ml和50μg/ml;S6和SM品系对氨苄青霉素和链霉素较敏感,固体培养中5．0－50．0μg/ml和50μg/ml;S6和SM品系对氨苄青霉素和链霉素较敏感,固体培养中5．0－50．0μg/ml的氨苄青霉素对它们有致死作用;液体培养中链霉素的的抑制浓度是5．0μg/ml,固体培养中链霉素的致死浓度是50μg/ml;S6和SM对氯霉素最敏感,液体培养时0．1μg/ml的氯霉素可抑制螺旋藻的生长,固体平板致死浓度是1．0μg/ml。应用电转化法将带有CAT基因片段的同源重组质粒导入螺旋藻细胞,用含有20μg/ml氯霉素Zarrouk固体平板筛选出了抗性转化子,研究结果表明,氯霉素是螺放藻转化系统中理想的抗性选择试剂。     

对虾白斑杆状病毒对螯虾血淋巴原代细胞的感染

应用螯虾血淋巴细胞的原代培养系统，作为对虾白的斑杆状病毒（white spot bacilliform virus,WSBV)的替代宿主，进行体外感染实验。通过PCR及RNA点杂交的方法监测WSBV的DNA复制、转录情况。结果显示，来源于对虾的WSBV可以感染体外培养的螯虾原代血淋巴细胞，并在其中增殖；WSBV感染螯虾原代血淋巴细胞后6h左右病毒开始大量复制，感染后的细胞可以存活数目。在目前虾细胞系尚未建立之前，螯虾血淋巴原代细胞可以作为研究WSBV感染、转录和复制等机理的替代系统。     

中国对虾组织细胞中酚氧化酶活力的研究

运用酶细胞化学技术，显示中国对虾（Fenneropenaeus chinensis）淋巴器、皮肤、鳃、肝胰腺、中肠育囊和中肠这几种组织细胞中的酚氧化酶活性，在透射电镜下观察各组织中细胞内酚氧化酶的活性部位；观察在受病毒感染的细胞内酚氧化酶对病毒的作用。结果表明，在健康对虾的组织细胞中，基本不表现酚氧化酶活性，而在受病毒感染的对虾中，不同的组织表现不同程度的酚氧化酶活性。其中，尤以淋巴器和皮肤的细胞中酚氧化酶活性最强，在淋巴器和皮肤这两个组织的细胞中，都可看到酚氧化酶对病毒结构的破坏作用。中国对虾淋巴器具有对血淋巴中有害异物进行过滤的作用，酚氧化酶在这一过程中发挥了重要作用。     

带HSV—tk基因的重组腺病毒治疗小鼠实体瘤的研究

在完成一系列离体实验川的基础上进一步进行了活体研究，离体实验表明，小鼠肉瘤细胞5180在感染重组腺病毒ADV／RSV－tk后对GCV的处理显示出致死敏感性。因4L以S180肿瘤细胞进行活体实验，小鼠腋下接种3×106S180细胞，当能触摸到瘤块时在瘤内注入ADV／RSV－tk，并腹腔注射GCV连续五天；种瘤后10天杀死小鼠剥离瘤块称重，治疗组瘤重为对照组的1／14。实验结果表明，以腺病毒为载体介导HSV－tk基因结合GCV作用对肿瘤细胞有强杀伤性，是有应用前景的肿瘤基因治疗的一种疗法。     

PSA空气分离吸附过程中的压降特性研究

根据PSA分离空气制氧的基本理论，通过对我们自行研制的产氧量为Q＝（1－5）L／min的双吸附柱的小型PSA分离空气制氧系统进行的吸附过程的压力降的计算，分析了影响空气流经多孔吸附介质压降特性的操作参数，分子筛结构参数等重要因素。结果表明：（1）空气流经PSA吸附柱多孔吸附介质的压降随流速的增大而增大，在较低流速范围内（v=0.05m/s-0.1m/s)，流速对压降的影响较小，在流速较高时，流速对压降的影响较大；（2）压降随空隙率的增大而减小，对于较高流速，低空隙率范围内（ε＝0．32－0．4）空隙率对压降影响很大，是影响压降的最主要因素；（3）压降随多孔吸附介质颗粒直径的增大而减小，在吸附介质颗粒直径较小的范围内（d=1.6-2.0mm)这种变化较明显。     

纳米TiO2光诱导杀伤 Bel-7402人体肝癌细胞研究

在光诱导条件下，采用HE染色法和四甲基偶氮唑蓝比色法（MTT法），研究了纳米TiO2对Bel-7402人体肝癌细胞的杀伤作用，考察了在不同纳米TiO2浓度、不同光照时间下纳米TiO2的抑瘤效果，并且对抑瘤机制进行了探讨．结果发现：在光诱导条件下，适宜的TiO2浓度具有较高的抑瘤率，同时抑瘤过程表现出类似一级反应的动力学规律；在光诱导条件下，纳米TiO2产生的活性氧组分与癌细胞膜内外的生物大分子反应，引起广泛的细胞结构破坏；造成癌细胞内Ca^2＋离子稳态失去平衡；引发细胞微管相关蛋白2（MAP-2）表达的变化，促进微管发生重组，从而导致细胞凋亡和坏死．     

反转录病毒介导的HSV-tk/ACV系统基因治疗的安全性研究

研究了反转录病毒介导的ＨＳＶ－ｔｋ／ＡＣＶ系统基因治疗脑肿瘤的安全性。     

PolyHEMA and polyHEMA-poly(MMA-co-AA) as substrates for culturing Vero cells

Poly (2-hydroxyethyl methacrylate), polyHEMA, is known to prevent cellular attachment and spreading. This hydrogel is used to culture cells not dependent on anchorage. Blending polyHEMA with a copolymer of methyl methacrylate and acrylic acid introduces negative charges to the hydrogel and improves its mechanical characteristics. PolyHEMA and the blend were tested for attachment and proliferation of Vero cells. Dense and porous samples of the hydrogels were used. Attachment assays included cellular quantification with MTT photometry and cellular morphology with the scanning electron microscopy after 2 h culture. Proliferation assays were carried out with 5 and 10 days culture. Cellular morphology included cytochemistry of resin sections and scanning electron microscope observations. Hydrogels allowed a few cells to attach and proliferate. The cells growing on the surface of hydrogels were organized in various layers and showed a differential morphology. Cells located inside the pores remained rounded. The hydrogels showed the possibility of inducing differentiated phenotypic expression.     

Analytical‐Based Methodologies for Examining the In Vitro Absorption,Distribution, Metabolism,and Elimination (ADME) of Silver Nanoparticles

The clinical applications of silver nanoparticles (AgNPs) remain limited due to the lack of well‐established methodologies for studying their nanokinetics. Hereby, the primary goal is to adapt a suite of analytical‐based methodologies for examining the in vitro absorption, distribution, metabolism, and elimination of AgNPs. Vero 76 and HEK 293 cells are exposed to ≈10‐nm spherical AgNPs⁺ and AgNPs^? at relevant concentrations (0–300 µg mL^?1) and times (4–48 h). Absorption: Inductively coupled plasma optical emission spectroscopy (ICP‐OES) demonstrates that the two AgNP formulations are not bioequivalent. For example, different bioavailabilities (C _maximum < 20.7 ± 4% and 6.82 ± 0.4%), absorption times (T _maximum > 48 and ≈24 h), and absorption rate laws (first‐ and zeroth‐order at 300 µg mL^?1) are determined in Vero 76 for AgNPs⁺ and AgNPs^?, respectively. Distribution: Raman and CytoViva hyperspectral imaging show different cellular localizations for AgNPs⁺ and AgNPs^?. Metabolism: Cloud point extraction (CPE)‐tangential flow filtration (TFF) reveal that ≤ 11% ± 4% of the administered, sublethal AgNPs release Ag⁺ and contribute to the observed cytotoxicity. Elimination: ICP‐OES‐CPE suggests that AgNPs are cleared via exocytosis.     

Glycyrrhizic‐Acid‐Based Carbon Dots with High Antiviral Activity by Multisite Inhibition Mechanisms

With the gradual usage of carbon dots (CDs) in the area of antiviral research, attempts have been stepped up to develop new antiviral CDs with high biocompatibility and antiviral effects. In this study, a kind of highly biocompatible CDs (Gly‐CDs) is synthesized from active ingredient (glycyrrhizic acid) of Chinese herbal medicine by a hydrothermal method. Using the porcine reproductive and respiratory syndrome virus (PRRSV) as a model, it is found that the Gly‐CDs inhibit PRRSV proliferation by up to 5 orders of viral titers. Detailed investigations reveal that Gly‐CDs can inhibit PRRSV invasion and replication, stimulate antiviral innate immune responses, and inhibit the accumulation of intracellular reactive oxygen species (ROS) caused by PRRSV infection. Proteomics analysis demonstrates that Gly‐CDs can stimulate cells to regulate the expression of some host restriction factors, including DDX53 and NOS3, which are directly related to PRRSV proliferation. Moreover, it is found that Gly‐CDs also remarkably suppress the propagation of other viruses, such as pseudorabies virus (PRV) and porcine epidemic diarrhea virus (PEDV), suggesting the broad antiviral activity of Gly‐CDs. The integrated results demonstrate that Gly‐CDs possess extraordinary antiviral activity with multisite inhibition mechanisms, providing a promising candidate for alternative therapy for PRRSV infection.     

Cascade Immune Activation of Self-Delivery Biomedicine for Photodynamic Immunotherapy Against Metastatic Tumor

Photodynamic therapy (PDT) can generate reactive oxygen species (ROS) to cause cell apoptosis and induce immunogenic cell death (ICD) to activate immune response, becoming a promising antitumor modality. However, the overexpressions of indoleamine 2,3-dioxygenase (IDO) and programmed cell death ligand 1 (PD-L1) on tumor cells would reduce cytotoxic T cells infiltration and inhibit the immune activation. In this paper, a simple but effective nanosystem is developed to solve these issues for enhanced photodynamic immunotherapy. Specifically, it has been constructed a self-delivery biomedicine (CeNB) based on photosensitizer chlorine e6 (Ce6), IDO inhibitor (NLG919), and PD1/PDL1 blocker (BMS-1) without the need for extra excipients. Of note, CeNB possesses fairly high drug content (nearly 100%), favorable stability, and uniform morphology. More importantly, CeNB-mediated IDO inhibition and PD1/PDL1 blockade greatly improve the immunosuppressive tumor microenvironments to promote immune activation. The PDT of CeNB not only inhibits tumor proliferation but also induces ICD response to activate immunological cascade. Ultimately, self-delivery CeNB tremendously suppresses the tumor growth and metastasis while leads to a minimized side effect. Such simple and effective antitumor strategy overcomes the therapeutic resistance against PDT-initiated immunotherapy, suggesting a potential for metastatic tumor treatment in clinic.     

Photovoltaic devices employing ternary PbS_xTe_(1-x) nanocrystals

Colloidal quantum dots(CQDs), especially lead chalcogenide CQDs, are regarded as promising materials for the next generation solar cells, due to their large absorption coefficient, excellent charge transport,and multiple exciton generation effect. We successfully synthesized highly-crystalline, monodispersed,well-alloyed PbS_xTe_(1-x) nanocrystals via a one-pot, hot injection reaction method. Energy-filtered transmission electron microscopy suggested that the S and Te anions were uniformly distributed in the alloy nanoparticles. The photovoltaic performance of CQD solar cells based on ternary PbS_xTe_(1-x) was reported for the first time. The photovoltaic devices using PbS_xTe_(1-x) were more efficient than either the pure PbS or the PbTe based devices. In addition, the PbS_xTe_(1-x) based devices showed a significantly improved stability than that of the PbTe based devices.     

SARS-CoV-2 RBD Neutralizing Antibody Induction is Enhanced by Particulate Vaccination

The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein is a candidate vaccine antigen that binds angiotensin-converting enzyme 2 (ACE2), leading to virus entry. Here, it is shown that rapid conversion of recombinant RBD into particulate form via admixing with liposomes containing cobalt-porphyrin-phospholipid (CoPoP) potently enhances the functional antibody response. Antigen binding via His-tag insertion into the CoPoP bilayer results in a serum-stable and conformationally intact display of the RBD on the liposome surface. Compared to other vaccine formulations, immunization using CoPoP liposomes admixed with recombinant RBD induces multiple orders of magnitude higher levels of antibody titers in mice that neutralize pseudovirus cell entry, block RBD interaction with ACE2, and inhibit live virus replication. Enhanced immunogenicity can be accounted for by greater RBD uptake into antigen-presenting cells in particulate form and improved immune cell infiltration in draining lymph nodes. QS-21 inclusion in the liposomes results in an enhanced antigen-specific polyfunctional T cell response. In mice, high dose immunization results in minimal local reactogenicity, is well-tolerated, and does not elevate serum cobalt levels. Taken together, these results confirm that particulate presentation strategies for the RBD immunogen should be considered for inducing strongly neutralizing antibody responses against SARS-CoV-2.     

Infrared absorption by methane isotopes near 2999 cm(-1): an analytical method using the Zeeman split He-Ne laser line at 2999.24 cm(-1)

We report the strengths and locations of the absorption lines of CH(3)D, (13)CH(4), and (12)CH(4) in the vicinity of the helium-neon laser line at 2999.24 cm(-1). In this region we find intrinsically strong lines of the rare species overlapping, but not precisely coincident with, intrinsically weak lines of the major species. In methane of normal isotopic composition, the lines of all three species have comparable strengths. We show how absorption measurements of the He-Ne laser, with Zeeman splitting, can be used to determine variations of the concentrations of the rare species from standard concentrations at a calculated precision of 0.5%0.     

Construction of highly stable selenium nanoparticles embedded in hollow nanofibers of polysaccharide and their antitumor activities

Nanotechnologies have been exploited to develop safe and effective medicines and pharmaceuticals.In the present study,a novel functional nanomedicine constructed from a bioactive polysaccharide and selenium nanoparficles (SeNPs) was developed.A highly-branched [3-(1→3)-D-glucan (AF1) with high anti-tumor activity was used to self-assemble hollow nanofibers with an apparent average diameter of 92 nm;Se nanopartides were synthesized via the reduction of sodium selenite.The results of light scattering,transmission electron microscopy,and X-ray diffraction demonstrated that the spherical SeNPs with a mean diameter of 46 nm were entrapped in the cavities of the AF1 hollow nanofibers through the formation of Se-O bonds between SeNPs and AF1,leading to the good dispersion and high stability in water for over 16 months.In vitro and in vivo assays indicated that the AF1-Se nanocomposite had higher anti-tumor activities against breast cancer.Furthermore,AF1-Se displayed a broad-spectrum inhibition against human cancers with low half maximal inhibitory concentration (IC50) values and low toxicity to normal cells.Particularly,the inhibition ratio of AF1-Se against MCF-7 cancer cells reached 75％ at a concentration of 200 μg.mL-1 with 29 μM Se content,much higher than that by treatment with AF1 alone,suggesting a strong synergic effect and nano impact.Overall,we developed a method for increasing the stability,anti-tumor activity,and safety of SeNPs by wrapping with bioactive polysaccharides.     

Monitoring decay of black gum wood (Nyssa sylvatica) during growth of the shiitake mushroom (Lentinula edodes) using diffuse reflectance infrared spectroscopy

Abstract diffuse reflectance infrared spectroscopy (DRIFT) and elemental analysis were employed to monitor biodegradation of black gum wood (Nyssa sylvatica) during growth of the shiitake mushroom (Lentinula edodes). Black gum was decayed for up to 4.3 years by L. edodes, during which time it was sampled at 19, 31, and 52 months. Biodegraded woods displayed increased % O (w/w) and decreased % C (w/w) relative to the undecayed control. The DRIFT spectra of decayed black gum showed a decrease in relative intensity of absorption bands at 1735 cm(-1) assigned to carboxyl functional groups from xylans and an increase in the absorption band at 1640 cm(-1) assigned to conjugated carbonyl groups originating from lignin. Xylan decay was rapid initially but slowed after 19 months; however, oxidative decay of the lignin side chains occurred throughout the 52-month decay period. Overall elemental and DRIFT data show that both polysaccharides and lignin were decayed during cultivation of the edible white-rot fungus.