Hemagglutinating 7S subunits of 19S cold agglutinins

Two highly purified IgM cold agglutinins have been mildly reduced yielding 7S subunits, with interchain covalent bonds intact. These subunits retained most of the cold-agglutinin activity as well as the specificity of the parent antibodies. However, as might be anticipated from theories of the importance of antibody size and number of subunits for complement binding, the IgM subunits were only very weakly lytic compared with the intact cold agglutinins. The findings are consistent with the presence of ten antibody-combining sites on the IgM molecule.     

Complement-fixing properties of pepsin-treated rabbit and sheep antibodies

Rabbit antibody with a sedimentation coefficient of 7S was digested with pepsin to yield the 5S fragment. Washed specific precipitates of 5S antibody and egg albumin, when added to guinea pig serum, fixed up to 40 percent of the total complement. This fixation could not be attributed to contamination with 7S antibody. Absorption of guinea pig serum with washed precipitates of 5S antibody and antigen removed that portion of complement which was fixed by fresh 5S antibody-antigen aggregates, but not that fixed by 7S antibody-antigen aggregates. The presence of 0.001M ethylenediaminetetraacetic acid prevented this absorption of complement by the 5S aggregates.     

Nucleotide sequence of KB cell 5S RNA

The nucleotide sequence of 5S RNA derived from KB carcinoma cell ribosomes has been determined. The molecule has a length of either 120 or 121 nucleotides with uridine at its 3'-terminus and guanylic acid at its 5'-terminus. If, in addition to Watson-Crick base-pairing, one accepts occasional base-pairing of guanylic acid to uridylic acid, long sequences of complementary nucleotides can be identified within the molecule. Two regions of the molecule contain sequences complementary to four or five bases in the pentanucleotide sequence guanylic acid, ribothymidylic acid, pseudouridylic acid, cytidylic acid, guanylic acid, which is common to most transfer RNA molecules. This is the first time the sequence of an animal-cell RNA has been determined.     

大豆籽粒贮藏蛋白11S/7S比值与生态因子相关关系的研究

 2001～2002年在河南省夏大豆主产区的5个试点，以豫豆25号为材料分13期播种，将109个大豆样本的11S/7S比值与气象、土壤养分和海拔、纬度等29个生态因子进行了逐步回归统计分析。结果表明，6个生态因子与大豆11S/7S比值密切相关。并明确了在夏大豆鼓粒成熟期较低的昼夜温差有利于提高11S/7S比值，鼓粒成熟期日照时数与11S/7S比值呈二次曲线关系，当日照时数在110.8 h时，11S/7S比值最小，当日照时数在459.2h时，11S/7S比值最大；在幼苗期较高的均温和较小的昼夜温差有利于提高11S/7S比值；分枝期较大的昼夜温差利于提高11S/7S比值；土壤中钾含量与11S/7S比值呈二次曲线关系，较低的土壤钾含量有利于11S/7S比值的提高，当土壤钾含量在1.32%时，11S/7S比值最小, 当土壤钾含量在0.83%时，11S/7S比值最大。在本试验研究范围内，其它生态因子对大豆11S/7S比值无显著影响。     

Efficiency of the first component of complement (C'1) in the hemolytic reaction

With the use of the first component of guinea pig complement (C'1) labeled in vivo with (14)C-amino acids, we have obtained evidence that, under the conditions required for the assay of C'1, each molecule of C'1 capable of interaction with cell surface antigen-antibody complexes is capable of initiating the reaction sequence that leads to lysis of the cell.     

Evidence for in vivo reaction of antibody and complement to surface antigens of human cancer cells

The immune adherence test was used to determine whether antibody and complement in cancer patients are fixed in vivo to tumor cells. Human erythrocytes adhered in vitro to the surface of human cancer cells obtained from autopsy and biopsy. Adherence was enhanced by further addition of the C2 and C3 components of complement, and was diminished by preliminary treatment with antibody to C3 (that is, to beta1C-globulin). The results suggest that tumor associated membrane antigens form complexes in vivo with antibodies and complement.     

维生素C对β-伴大豆球蛋白诱导的仔猪肠上皮细胞炎性损伤的保护作用

为分析不同浓度维生素C(vitamin C,V_C)对β-伴大豆球蛋白(7S)诱导的仔猪肠上皮细胞(IPEC-J2)炎性损伤的保护作用,取对数生长期的IPEC-J2用于试验,随机分为对照组、7S模型组(5 mg·mL^-1 7S)和V_C(25、50、100、200、400、600、800、1 000 μmol·L^-1)保护组。细胞培养24 h后采用CCK-8法检测细胞存活率,倒置显微镜观察细胞形态学变化,ELISA法检测细胞上清液中LDH、ALP、DAO、IFABP1含量和IL-1β、IL-6、TNF-α、IL-4、IL-10的分泌水平,用qRT-PCR法检测IL-1β、IL-6、TNF-α、IL-4和IL-10 mRNA相对表达量。结果显示:7S可显著(P<0.01)降低IPEC-J2活力、破坏细胞膜完整性,上调细胞促炎性因子和下调抗炎因子的产生;与7S模型组相比,同时添加7S和V_C的试验组细胞活力增加,细胞上清液中LDH、ALP、DAO、IFABP1含量显著(P<0.01)降低,促炎因子IL-1β、IL-6、TNF-α分泌水平降低,抗炎因子IL-4和IL-10的分泌水平升高。因此,不同浓度V_C均可保护由7S诱导引起的仔猪肠上皮细胞损伤,100 μmol·L^-1 V_C的修复和保护作用最佳。     

我国试制Rose Bengal平板抗原用于绵羊布氏杆菌病诊断结果的分析

本文报道以布氏杆菌虎红平板凝集试验与标准布氏杆菌玻板凝集试验、试管凝集试验和补体结合试验对照,对1097份绵羊血清进行布氏杆菌病阳性率和符合率的观察。试验证明:虎红平板试验的阳性率与玻板和补反试验的阳性率相近,而与试管凝集试验的阳性率差异较大.同时与对照试验的阳性符合率均为低下.     

Anaphylatoxin release from the third component of human complement by hydroxylamine

Treatment of highly purified preparations of the third component of complement (C3) with 0.5M hydroxylamine at 20 degrees C for 15 to 30 minutes, followed by acidification, resulted in dissociation of a peptide from the C3 molecule. The isolated fragment (molecular weight, 7600) resembled enzymatically liberated anaphylatoxin (C3a) with respect to size, charge, amino acid composition, and biological activity. Its capacity to contract smooth muscle was inhibitable by antihistamines; it also produced tachyphylaxis and desensitization of the guinea pig ileum to C3a. Thus native C3 probably contains an esterlike bond and hydroxylamine-liberated anaphylatoxin may represent one of the polypeptide chains of the C3 molecule.     

Chloramphenicol-specific antibody

Antibody to the antibiotic chloramphenicol was obtained by immunizing rabbits with a chloramphenicol derivative coupled to bovine gamma globulin. Production of antibody was demonstrated by the precipitin and complement fixation reactions with "reduced chloramphenicol" coupled to rabbit serum albumin as the test antigen. Specificity of the antibody was confirmed in that crystalline chloramphenicol completely inhibited complement fixation and precipitin reactions. "reduced chloramphenicol" coupled to human serum albumin provides an antigen for the detection of antibody to chloramphenicol, if it occurs in human serum in dyscrasias. With quantitative complement fixation, as little as 10(-5) microg (4 x 10(-14) mole) of chloramphenicol was detectable by the inhibition assay.     

Regenerative adsorption and removal of H2S from hot fuel gas streams by rare earth oxides

Sorbent materials that allow for high-temperature, regenerative desulfurization of fuel gas streams for the anode of a solid oxide fuel cell have been developed. Reversible adsorption of H2S on cerium and lanthanum oxide surfaces is demonstrated over many cycles at temperatures as high as 800 degrees C, on both fresh or presulfided sorbents, and at very high space velocities. The adsorption and desorption processes are very fast, and removal of H2S to sub-parts per million levels is achieved at very short (millisecond) contact times. Any type of sulfur-free gas, including water vapor, can be used to regenerate the sorbent surface. Preferably, the anode off-gas stream is used to sweep the desorbed H(2)S to a burner.     

大豆7S与11S组分酶解物混合蛋白在猪肉肠中的应用研究

[目的]研究适合猪肉肠加工的专用蛋白。[方法]以中豆36为原料,以质构特性、肉肠得率为评价指标,比较了添加不同比例和不同添加量的7S与11S组分酶解物混合蛋白对肉肠品质的影响。[结果]添加不同比例7S与11S酶解蛋白的肉肠质构特性优于仅添加7S酶解蛋白或仅添加11S酶解蛋白的肉肠。当7S与11S酶解蛋白的添加比例为3∶1时,肉肠的质构特性最佳,且肉肠的得率最高。7S与11S酶解蛋白的添加比例不变,当混合蛋白的添加量为0.5%时,肉肠的质构特性最佳。混合蛋白的添加量为2.0%时,肉肠的得率最高;添加量为0.5%时,肉肠的得率次之。正交试验的结果表明,当7S与11S酶解蛋白的添加比例为3.5∶1,混合蛋白的添加量为0.5%时,肉肠的得率与质构特性均最佳。[结论]7S与11S复配酶解蛋白可以显著地改善肉肠的质构特性和得率。     

Stibnite (Sb2S3) Solubility in Sodium Sulfide Solutions

The solubility of stibnite ( Sb(2)S(3)) was measured at 25 degrees C and 1 atmosphere in solutions ranging from 0.45 to 7.16 percent Na(2)S by weight. Sb(2)S(3): Na(2)S mole ratios of saturated solutions range from 0.238 to 0.403. Stibnite solubility increases at an increasing rate with rising Na(2)S concentration. The reaction that best fits the experimental data is 2Sb(2)S(3) + HS- + OH-= Sb(4)S(7)(2-) + H(2)O, for which an equilibrium constant was estimated to be about 5.0.     

Immunoglobulin M antibodies with ten combining sites

Immunoglobulin M rabbit antibodies to a hapten are shown to have ten binding sites per molecule. The affinity for the specific hapten is approximately 100 times greater for one-half of the sites than for the other half. All sites are retained in the five 7S subunits produced by reduction and alkylation of the immunoglobulin M. Each of the 7S subunits of the IgM molecule apparently has one strong and one weak site.     

Hemoglobins S and C interfere with actin remodeling in Plasmodium falciparum-infected erythrocytes

The hemoglobins S and C protect carriers from severe Plasmodium falciparum malaria. Here, we found that these hemoglobinopathies affected the trafficking system that directs parasite-encoded proteins to the surface of infected erythrocytes. Cryoelectron tomography revealed that the parasite generated a host-derived actin cytoskeleton within the cytoplasm of wild-type red blood cells that connected the Maurer's clefts with the host cell membrane and to which transport vesicles were attached. The actin cytoskeleton and the Maurer's clefts were aberrant in erythrocytes containing hemoglobin S or C. Hemoglobin oxidation products, enriched in hemoglobin S and C erythrocytes, inhibited actin polymerization in vitro and may account for the protective role in malaria.     

11S通过NF-κB信号通路引起猪小肠上皮细胞损伤

通过体外培养猪小肠上皮细胞(IPEC-J2),研究大豆球蛋白(11S)对猪小肠上皮细胞的影响。将IPEC-J2细胞分为6组[A(对照组)、B、C、D、E和F],各组中分别添加0、1、5、10、5、5 mg·mL^-1的11S,并且在E组和F组分别添加1 μmol·L^-1吡咯烷二硫代氨基甲酸盐(PDTC)和1 μmol·mL^-1 Nω-硝基-L-精氨酸甲酯(L-NAME)。分别于8、16、24 h,用CCK-8法检测细胞存活率,用ELISA法检测细胞一氧化氮(NO)、二胺氧化酶(DAO)、5-羟色胺(5-HT)、白细胞介素6(IL-6)和白细胞介素10(IL-10)含量,用western blot法检测细胞p-NF-κB p65、iNOS、COX-2的蛋白表达量,用qPCR法检测细胞NF-κB p65、IKKβ、iNOS、IKKα、COX-2 mRNA的相对表达量。结果表明:11S可以降低猪小肠上皮细胞存活率,添加PDTC和L-NAME可以提高小肠上皮细胞存活率;11S可促进NO、DAO、5-HT和IL-6的分泌,降低IL-10的分泌,增加p-NF-κB p65、iNOS、COX-2的蛋白表达量及NF-κB p65、IKKβ、iNOS、IKKα、COX-2 mRNA的相对表达量,添加PDTC和L-NAME可抑制11S的作用。综上,11S可引起猪小肠上皮细胞损伤,随着11S浓度的增大,损伤程度增加,PDTC和L-NAME可以降低11S对细胞的损伤。     

维生素A对大豆7S球蛋白致仔猪肠上皮细胞屏障功能损伤的影响

以仔猪肠上皮细胞(IPEC-J2)为研究对象,用大豆7S球蛋白作为诱导因素,通过检测细胞活力、细胞跨膜电阻(TEER)、荧光素钠渗透率、细胞膜完整性相关指标与紧密连接蛋白的mRNA表达情况,探究维生素A(V_A)对大豆7S球蛋白致IPEC-J2细胞屏障功能损伤的影响。结果显示:5.0 mg·mL^-1大豆7S球蛋白导致IPEC-J2活力、TEER与ZO-1、Claudin-1、Occludin的mRNA表达量极显著(P<0.01)降低,而荧光素钠渗透率和细胞培养液中碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)、二胺氧化酶(DAO)、肠型脂肪酸结合蛋白1(IFABP1)的含量极显著(P<0.01)升高;添加0.1和1 μmol·L^-1 V_A极显著提高了细胞活力(P<0.01),0.1~10 μmol·L^-1 V_A显著(P<0.05)缓解了大豆7S球蛋白导致的TEER、荧光素钠渗透率、细胞膜完整性相关指标与紧密连接蛋白mRNA表达的变化;10 000 μmol·L^-1 V_A反而加剧了这些影响。总体上,0.1~10 μmol·L^-1 V_A能通过保护细胞活力和细胞完整性、影响紧密连接蛋白的mRNA表达对大豆7S球蛋白导致的IPEC-J2细胞屏障功能损伤发挥保护作用,而10 000 μmol·L^-1 V_A反而加重了这种损伤。     

基于12S rRNA和16S rRNA序列的龟鳖类系统进化特征研究

[目的]研究龟鳖类的系统进化关系,为龟鳖类资源的保护和合理开发利用提供理论依据.[方法]采用PCR扩增和测序的方法,获得小鳄龟(Chelydra serpentina)的12S rRNA和16S rRNA序列,分别结合NCBI中其他龟鳖的同源性序列进行比对分析;基于Kimura双参数模型计算龟鳖类种间、属间、科间的遗传距离;采用邻接(NJ)法、最大简约(MP)法和最大似然(ML)法构建分子系统进化树.[结果]经比对后得到394 bp的12S rRNA-致序列和544 bp的16SrRNA一致序列,二者合并得到938 bp的联合序列.其中,可变位点327个,序列总变异率为34.9%,简约信息位点222个,单变异多态位点105个.T、C、A、G的平均含量分别为23.6%、24.1%、33.5%和18.7%,A+T含量为57.1%,G+C含量为42.8%.在327个可变位点中,转换数为61,颠换数为24,转换/颠换比率(R)为2.54.拟水龟属间的遗传距离为0.021~0.060,平均为0.467;淡水龟科8属之间的遗传距离为0.022~0.110,平均为0.0724;曲颈龟亚目7科(除平胸龟属外)间的遗传距离为0.071~0.123,平均为0.105.分子系统进化树显示,木纹龟属首先和陆龟科聚在一起,然后再与淡水龟科汇聚;中华花龟、大头乌龟与拟水龟属的成员相互镶嵌,聚成一支;鳄龟科、海龟科、棱皮龟科聚为一支;动胸龟科独成一支.[结论]应将龟亚科、淡水龟亚科提升为龟科、淡水龟科,并将大头乌龟、中华花龟并入拟水龟属,而平胸龟应从鳄龟科中分离出来,独立自成平胸龟科.