Release of protoplasts in the yeast phase of Histoplasma capsulatum without added enzyme

Cells of the yeast phase of the dimorphic systemic fungus pathogen Histoplasma capsulatum readily released large numbers of intact protoplasts without degradation of their cell walls by snail or microbial enzymes, previously regarded as a requirement for all yeast and mycelial fungal forms. Over 90 percent of "B" type yeast cells in the early logarithmic phase of growth released living protoplasts when incubated at 37 degrees C with 2 molar magnesium sulfate, whereas "A" type yeast cells required prior exposure for 24 hours to 2-deoxy-D-glucose before incubation in the 2 molar magnesium sulfate.     

Systemic lupus erythematosus: presence in human serum of an unusual acid-labile leukocyte interferon

A previously undescribed species of human leukocyte, or alpha, interferon is present in the serum of many patients with systemic lupus erythematosus. It was shown to be alpha-interferon by neutralization with specific antiserums, affinity column chromatography, and antiviral activity on bovine cells. However, 23 of 30 interferon samples tested were inactivated by incubation at pH 2, a characteristic of human "immune," or gamma, interferon. Multiple samples of interferon from the same patient had similar biological properties, but samples from different patients were not all identical, suggesting that several variants of this species of human alpha-interferon may exist.     

Adenosine 3',5'-monophosphate modulates thyrotropin receptor clustering and thyrotropin activity in culture

A biologically active rhodamine conjugate of thyrotropin binds at 4 degrees C to diffusely distributed membrane thyrotropin receptors which patch and become endocytosed into thyroid cells in a temperature-sensitive process. When the cells are first incubated with 8-bromo-cyclic adenosine monophosphate at 37 degrees C, the conjugate also binds to clustered receptors at 4 degrees C. Furthermore, 8-bromo-cyclic adenosine monophosphate reduces the amount of adenosine 3',5'-monophosphate (cyclic AMP) induced by thyrotropin. Hence, increased intracellular cyclic AMP induces receptor patching and reduces the concentration of cyclic AMP normally induced by thyrotropin. This suggests that cyclic AMP acts both as the second messenger of thyrotropin and also as the regulator of the level of thyrotropin receptors.     

Interferon: lack of detectable uptake by cells

No interferon, or at most a small fraction of that applied, is taken up by cells during the period of induction of antiviral activity. The lack of detectable adsorption was not influenced either by the concentration of interferon or the volume. The results were similar in both chicken and mouse systems.     

Antibody formation in nonimmune mouse peritoneal cells after incubation in gum containing antigen

Peritoneal cells from normal mice in a semisolid medium containing sheep erythrocytes were incubated at 37 degrees C for 2 or 3 days. During this period, hemolytic antibodies developed spontaneously. Arguments are presented that true de novo synthesis of antibody has taken place in previously uncommitted cells.     

Regulation of amino acid transport in kidney cortex of newborn rats

After incubation at 37 degrees C the subsequent uptake of alpha-aminoisobutyric acid, cycloleucine, glycine, and L-proline by newborn (as compared to adult) rat kidney cortex slices is enhanced. The effect is abolished by the presence of cycloheximide, actinomycin D, and high concentrations of the above-mentioned amino acids in the medium during the 37 degrees C incubation prior to measurement of uptake. The data suggest that there is an adaptive control mechanism which is expressed on incubation at 37 degrees C and which can regulate amino acid transport in newborn rat kidney cortex.     

TOLERANCE BETWEEN HOST AND DONOR TISSUE IN BIRDS

Two methods were used to develop tolerance in the host toward donor cells. In the first method chicken embryos were joined by the parabiotic union of the chorioallantoic membranes after 9 days of incubation. The second method consisted of the use of embryonic transplants of limb buds from donor embryo to host embryo. These transplants were made after 96 hours of incubation with chicken embryos. Other species used were incubated to comparable development. Both methods were successful in the development of tolerance. However, the degree of tolerance attained varied within each method.     

Antiviral resistance by the polyinosinic acid-poly (1-vinylcytosine) complex

The antiviral activities of analogs of the double-stranded complex of polyinosinic and polycytidylic acids [poly(I).poly(C)], which is a potent interferon inducer, have been studied. Structural changes that modify the polymer backbone substantially, such as loops or 2' --> 5' phosphodiester bonds, lead to decreased antiviral activity. Unexpectedly, however, the complex of polyinosinic acid and poly(1-vinylcytosine), which is only a much more distantly related analog of poly(I) . poly(C), shows high activity. It is postulated that the high activity is related to the reduction of the charge/mass ratio and to the existence of this complex in an aggregated state; these are two factors that generally enhance the uptake of compo unds by cells.     

重组猪α干扰素理化性状及其体外抗病毒活性研究

[目的]研究重组猪α干扰素（rPoIFN-α）半成品理化性状并对其体外抗病毒活性进行测试与鉴定。[方法]用HEp-2/VSV体系对3批rPoIFN-α蛋白进行抗病毒活性检测,以重组人IFN-α为参比品,测定干扰素效价;用0.25%胰蛋白酶HCl以及鼠抗猪α干扰素单克隆抗体作用已知效价的rPoIFN-α半成品,并检测各批次抗病毒活性,对rPoIFN-α理化性状进行评价;在猪肾细胞株（PK-15）上检测rPoIFN-α对猪细小病毒（PPV）和猪伪狂犬病毒（PRV）的致细胞病变抑制效应,观察rPoIFN-α的体外抗病毒活性。[结果]HEp-2/VSV体系滴定rPoIFN-α半成品效价可达1.5×105IU/ml,比活性达1.1×106IU/mg;rPoIFN-α经0.25%胰蛋白酶37℃作用1h,效价残留率低于1%,经HCl（pH=2.0）处理72h效价残留率高达95%以上,经56℃处理30min效价残留率高于47%,经鼠抗猪α干扰素单克隆抗体37℃作用1h后效价残留率约为1%;体外抗病毒试验表明,用50和500IU/mlrPoIFN-α可分别抑制PRV和PPV对PK-15细胞株致细胞病变效应。[结论]rPoIFN-α具有IFN-α的基本理化性状,其在体外可分别抑制PRV、PPV对PK-15细胞株致细胞病变效应,但剂量有差别。     

Inhibition of cell motility by interferon

Interferon derived from human leukocytes, human fibroblasts, and mouse fibroblasts was found to inhibit the motility of cultured cells. It inhibits the tumor-induced motility of capillary endothelial cells as well as the spontaneous migration of other cell types. The ability of a given preparation of interferon to inhibit the motility of a given cell type is proportional to its antiviral activity in that particular cell type. Antiserum to human leukocyte interferon neutralizes both the motility-inhibitory activity and the antiviral activity of this preparation.     

Interferon-resistant cell line lacks fatty acid cyclooxygenase activity

A clone of L1210 mouse leukemia cells selected for resistance to both the antiviral and anticellular properties of mouse interferon were essentially devoid of fatty acid cyclooxygenase activity. Experiments in which broken cell preparations were mixed or the two cell types were cultivated together failed to indicate the presence of a diffusible enzyme inhibitor. Fatty acid lipoxygenase activity of similar magnitude was detectable in both cell types. A selective impairment of fatty acid cyclooxygenase in interferon-resistant cells is consistent with recently described data suggesting that this enzyme may play a crucial role in mediating the antiviral and anticellular effects of interferon.     

重组猪α干扰素理化性状及其体外抗病毒活性研究(摘要)(英文)

[目的]研究重组猪α干扰素(rPoIFN-α)半成品理化性状并对其体外抗病毒活性进行测试与鉴定。[方法]用HEp-2/VSV体系对3批rPoIFN-α蛋白进行抗病毒活性检测,以重组人IFN-α为参比品,测定干扰素效价;用0.25%胰蛋白酶HCl以及鼠抗猪α干扰素单克隆抗体作用已知效价的rPOIFN-α半成品,并检测各批次抗病毒活性,对rPoIFN-α理化性状进行评价;在猪肾细胞株(PK-15)上检测rPoIFN-α对猪细小病毒(PPV)和猪伪狂犬病毒(PRV)的致细胞病变抑制效应,观察rPoIFN-α的体外抗病毒活性。[结果]HEp-2/VSV体系滴定rPoIFN-α半成品效价可达1.5×105IU/ml,比活性达1.1×106IU/mg;rPoIFN-α经0.25%胰蛋白酶37℃作用1h,效价残留率低于1%,经HCl(pH=2.0)处理72h效价残留率高达95%以上,经56℃处理30min效价残留率高于47%,经鼠抗猪α干扰素单克隆抗体37℃作用1h后效价残留率约为1%;体外抗病毒试验表明,用50和500IU/mlr PoIFN-α可分别抑制PRV和PPV对PK-15细胞株致细胞病变效应。[结论]rPoIFN-α具有IFN-α的基本理化性状,其在体外可分别抑制PRV、PPV对PK-15细胞株致细胞病变效应,但剂量有差别。     

猪α干扰素表达蛋白ab的抗病毒效果研究

[目的]探索猪α干扰素表达蛋白ab的抗病毒效果。[方法]通过测定猪α干扰素(PoIFN-α)表达的融合蛋白ab对接种水泡性口炎病毒(VSV)的牛肾细胞(MDBK)保护作用的效价,来研究其抗病毒效果。通过中和试验,测定保护50%细胞不产生病变所需PoIFN-α表达的融合蛋白ab的稀释度。[结果]PoIFN-α表达的融合蛋白ab具有显著的抗病毒作用,稀释度1∶4.9的2.0μg/ml ab蛋白溶液即可保护50%细胞不产生细胞病变。[结论]猪重组α干扰素具有高活性、纯度高、无毒副作用、无药物残留等特点,其研制与开发对猪生产实践和疾病防治具有重要意义。     

Solute concentration gradients in frog muscles at 0 degree C: active transport or adsorption?

In isolated frog muscle that has been incubated for 7 days at 0 degrees C invitro K(+) and Na(+) remain at normal concentrations. Amino acids are accumulated against a concentration gradient at this temperature; for example, glycine accumulates in muscle to a concentration ten times that in the external solution. The amount of cycloleucine accumulated is greater at 0 degrees C than at 25 degrees C. These findings, which are difficult to explain on the basis of metabolically linked active transport, are Consiststent with the view that solute accumulation by cell is the result of adsorption on spesific sites.     

TEMPERATURE-DEPENDENT HISTOTYPIC CHANGES IN WALKER CARCINOSARCOMA IN THE CHORIOALLANTOIS

Solid tumors grew in the chorioallantois of chick embryos after the topical inoculation of ascites tumor cells. The microscopic character of the growth varied depending on the temperature of incubation. At 32.5 degrees C a sarcomatous appearance was prominent; at 37.5 degrees C carcinomatous structure in several alveolar patterns predominated; at 42.5 degrees C growth was that of a "giant cell" carcinoma.     

大豆根系分泌物对土壤团聚体大小和稳定性的影响

采用水培实验法收集大豆植株根系分泌物,添加到黑土中,在25 ℃下培养30 d,研究了大豆根系分泌物对土壤水稳性团聚体大小、稳定性、土壤有机碳矿化率、土壤水溶性糖和多糖含量的影响.结果表明,大豆根系分泌物添加到土壤中,显著提高了土壤有机碳矿化率(P＜0.05),增加了土壤中水溶性糖和多糖含量(P＜0.05),但二者均随培养时间的推移而下降.大团聚体(粒径＞1 mm)的比例随培养时间的延长而显著增加(P＜0.05),小团聚体(粒径＜0.1 mm)的比例随培养时间的延长而显著降低(P＜0.05).水稳性团聚体含量皆显著高于对照(P＜0.05).培养时间越长,水稳性团聚体含量越高.培养1 d时,添加大豆根系分泌物的土壤水稳性团聚体比例是对照的2.7倍.     

苹果褐斑病潜育动态

【目的】褐斑病是导致苹果早期落叶的主要病害。研究旨在通过调查褐斑病的流行规律,为制定综合防治方案提供理论依据。【方法】2011和2012年,将褐斑病菌（Diplocarpon mali）分生孢子悬浮液分4-6次喷雾接种于富士苹果各龄期的叶片,接种后观测记录每个接种叶片第1个病斑出现的时间,每3 d观测一次,依此计算褐斑病在富士叶片上的平均潜育期、最短潜育期和显症历期。接种期间用全自动气象站,每30 min记录接种苹果树附近的气温、降雨量和相对湿度。【结果】苹果褐斑病在富士苹果叶片上的平均潜育期23.8 d;最短潜育期为8-20 d,平均为13.6 d;显症历期为12-54 d,平均为31.3 d。在显症历期内,不同的时期显症病斑数不同。6、7月份接种叶片比8月份接种叶片的最短潜育期和显症历期长。防雨棚内培育叶片的最短潜育期和显症历期长于自然条件下培育的叶片的最短潜育期和显症历期。苹果褐斑病在基部老龄叶片上潜育期短,在代谢旺盛的梢部叶片上潜育期长。苹果生长前期（6、7月份）接种叶片的潜育期显著的长于生长后期（8、9月份）接种叶片的潜育期。【结论】苹果褐斑病的显症是一个动态的过程,其潜育时间和显症历期都相对较长。除取决于病原与寄主的组合外,苹果褐斑病潜育时间和显症历期的长短主要受叶片龄期、衰老程度和生理状态,即叶片抗病性的影响。6-9月份是苹果褐斑病的主要发病期,在此期间气温对褐斑病潜育期的影响不大,而降雨和高湿能促进病斑显症。在褐斑病菌侵染后的15 d,甚至20 d内,使用内吸治疗性杀菌剂能抑制绝大部分潜育期病斑发病。     

棉纤维起始分化期基因枪介导的GhSuSy表达分析

蔗糖合酶(sucrose synthase)通过调节植物糖代谢介导棉纤维的起始和发育。为进一步研究棉纤维起始分化过程中蔗糖合酶的转录调控机制,克隆了GhSuSy基因5′端上游2 000 bp的启动子片段,构建了含LUC荧光报告基因的重组载体,采用基因枪瞬时转化技术,把重组载体DNA分别转化到棉花叶片和花瓣,比较分析了不同载体膜压力、不同轰击距离与孵育时间等条件下的荧光素酶(luciferase, LUC)活性。用优化后的条件检测了棉纤维起始分化期蔗糖合酶基因GhSuSy偶联的LUC在叶片和花瓣中的活性,并与GhSuSy表达、蔗糖合酶活性比较分析。结果显示：-0.09 MPa真空度下,可裂膜压力设为6.80 MPa,载体膜距离叶片7 cm,轰击2次转化效率最高,转化后样品孵育16 h左右LUC荧光信号最强;与叶片中LUC表达相比,花瓣中LUC荧光信号强、活性高,特别是开花当天(0 d)和开花后1 d(1 DPA)差异明显;在纤维起始分化的开花前3 d(-3 DPA)到开花后3 d(3 DPA),叶片和花瓣中LUC活性先升高后降低,在0和1 DPA的LUC活性最高,这一结果与GhSuSy的...     

NMRAL1对流感病毒复制的调控机制

【目的】流感病毒是一种人兽共患病原,常引起大流行,给人类健康造成巨大威胁,且流感病毒易发生变异,能不断逃逸宿主细胞的免疫反应,对现有抗流感药物产生耐药性,因此寻找抵抗流感的新方法迫在眉睫。研究通过探索NMRAL1(NmrA-like family domain-containing protein 1)对流感病毒复制的影响,并揭示其发挥作用的分子机制,为抗流感药物研发提供潜在靶点。【方法】采用siRNA干扰技术在A549细胞中下调表达NMRAL1,并通过Western Blot检测siRNA干扰后NMRAL1的表达水平;在下调表达NMRAL1的细胞中,分别感染A/Anhui/2/2005 (AH05) (H5N1)和A/WSN/33 (H1N1) 两株不同亚型流感病毒,利用蚀斑试验检测感染病毒后24和48 h细胞上清中的病毒滴度。为确定NMRAL1影响流感病毒复制的具体阶段,在HEK293T细胞中瞬时转染NMRAL1-Myc-pCAGGS质粒过表达NMRAL1,通过双荧光素酶报告系统检测过表达NMRAL1对流感病毒聚合酶活性的影响;使用免疫荧光技术对流感病毒NP蛋白进行染色,通过激光共聚焦试验观察下调表达NMRAL1对感染病毒后3、4、5、6和8 h NP蛋白在被感染细胞中的定位情况的影响,判断下调表达NMRAL1是否影响流感病毒的入核和出核过程;利用Western Blot检测下调表达NMRAL1对流感病毒各病毒蛋白表达的影响和对流感病毒激活I型干扰素通路下游IFN刺激基因（ISGs）表达的影响,利用间接免疫荧光试验进一步研究NMRAL1对流感病毒复制的影响。【结果】Western Blot检测发现NMRAL1 siRNA能显著下调NMRAL1表达,在下调表达NMRAL1的A549细胞中分别感染H5N1和H1N1病毒,并通过蚀斑试验检测感染病毒后细胞上清中的病毒滴度,结果显示在下调表达NMRAL1的细胞中,感染流感病毒后24和48 h收取的细胞上清中病毒滴度显著下降,表明NMRAL1能促进不同亚型流感病毒的复制;为进一步探索NMRAL1调控流感病毒复制的具体机制,利用双荧光素酶报告系统检测流感病毒聚合酶活性,发现过表达NMRAL1对流感病毒聚合酶活性无明显影响;激光共聚焦试验结果显示下调NMRAL1表达不影响NP蛋白的入核和出核过程,同时Western Blot检测表明下调NMRAL1表达不影响各病毒蛋白的表达;但荧光定量PCR试验结果显示下调NMRAL1表达能够促进流感病毒感染诱导的IFN-β mRNA水平上升,且Western Blot检测发现下调表达NMRAL1促进I型干扰素通路下游的MxA和IFITM3抗病毒蛋白的表达,与此同时,间接免疫荧光试验结果显示下调NMRAL1表达可显著抑制流感病毒复制。【结论】在流感病毒感染过程中,NMRAL1不影响流感病毒的入侵以及转录翻译过程,而是通过抑制I型干扰素通路激活从而抑制MxA、IFITM3等抗病毒因子的表达,最终促进流感病毒复制。研究证实宿主因子NMRAL1正调控流感病毒的复制,丰富了参与流感病毒复制的宿主因子网络。