Relationship of idiotypes of the anti-p-azophenylarsonate antibodies of A/J and BALB/c mice

It has previously been shown that A/J anti-Ar antibodies contain 2 different families of cross-reactive idiotypes, referred to as the major and minor idiotypes populations. The present report shows that the minor A/J idiotype is related to a major idiotype of BALB/c anti-Ar antibodies. Anti-idiotype directed against the minor A/J idiotype binds 5 to 10% of A/J anti-Ar but an average of about 40% of BALB/c anti-Ar. This BALB/c population corresponds to the major BALB/c anti-Ar idiotype. For individual BALB/c anti-Ar preparations the maximum percentages of antibody bound by anti-id directed to A/J or BALB/c anti-Ar are very similar. Anti-id reactive with the minor A/J idiotypic population suppressed the formation of the BALB/c major idiotype when injected into BALB/c mice. Adsorption experiments showed that only about one-third of the minor A/J population is related to the BALB/c idiotype and that the expression of this idiotype is highly variable in individual A/J sera. Several types of evidence, obtained with hybridoma products expressing the major A/J idiotype, revealed no detectable relationship between the major A/J and BALB/c anti-Ar idiotypes.     

Identification of two mismatch-binding activities in protein extracts of Schizosaccharomyces pombe.

We have performed band-shift assays to identify mismatch-binding proteins in cell extracts of Schizosaccharomyces pombe. By testing heteroduplex DNA containing either a T/G or a C/C mismatch, two distinct band shifts were produced in the gels. A low mobility complex was observed with the T/G substrate, while a high mobility complex was present with C/C. Further analysis of the mismatch-binding specificities revealed that the T/G binding activity also binds to T/C, C/T, T/T, T/-, A/-, C/-, G/-, G/G, A/A, A/C, A/G, G/T, G/A, and C/A substrates with varying efficiencies, but not binds to C/C. The C/C binding activity efficiently binds to C/C, T/C, C/T, C/A, A/C, C/-, and weakly also to T/T, while all other mispairs are not recognized. Protein extracts of a mutant strain, defective in the mutS homologue swi4, displayed both mismatch-binding activities. Thus, swi4 does not encode for either one of the mismatch-binding proteins.     

Biometric analysis of testicular development in Africander cattle

A total of 208 Africander bulls was examined clinically and genetically. Of these, 113 were selected to elaborate a table on the testicular development in this race. The selection criteria were, absolute certainty in age, intervals with greater number of observations and with lesser coefficient of variation. The regressions and simple correlations for the following characteristics were studied: Age-Scrotal Circumference (A/SC), Age-Left Length (A/LL), Age-Right Length (A/RL), Age-Ratio of Age to Scrotal Circumference (A/RASC), Scrotal Circumference-Left Length (SC/LL) and Scrotal Circumference-Right Length (SC/RL). All these regressions are linear. The regression coefficient were also compared, using the "t-test" for the following: A/RL-A/LL, A/SC-A/LL, A/SC-A/LL, A/SC-A/RL, A/RASC-A/RAL and SC/RL-SC/LL. The difference is not significant for A/RL-A/LL and SC/RL-SC/LL (P>0.05), but it is significant for A/SC-A/LL, A/SC-A/RL and A/RASC-A/RAL (P<0.01).     

Relaxation of recognition sequence of specific endonuclease HindIII.

Under the standard reaction conditions, the restriction endonuclease HindIII cleaves double-stranded DNA, within the recognition sequence--A/AGCTT--at the position indicated by the arrow. In the presence of dimethyl sulfoxide the substrate specificity of this enzyme is reduced and cleavages occur at additional sites. We have determined the secondary sites in pBR322 DNA recognized by HindIII endonuclease under relaxed conditions and found that it cleaves the hexanucleotides: G/AGCTT, A/GGCTT, A/TGCTT, A/ATCTT, A/AGCCT, A/AGCAT, A/AGCGT, A/AGCTC, at the positions indicated by the arrows, producing fragments with cohesive ends.     

Interaction of human pancreatic ribonuclease with human ribonuclease inhibitor. Generation of inhibitor-resistant cytotoxic variants

Mammalian ribonucleases interact very strongly with the intracellular ribonuclease inhibitor (RI). Eukaryotic cells exposed to mammalian ribonucleases are protected from their cytotoxic action by the intracellular inhibition of ribonucleases by RI. Human pancreatic ribonuclease (HPR) is structurally and functionally very similar to bovine RNase A and interacts with human RI with a high affinity. In the current study, we have investigated the involvement of Lys-7, Gln-11, Asn-71, Asn-88, Gly-89, Ser-90, and Glu-111 in HPR in its interaction with human ribonuclease inhibitor. These contact residues were mutated either individually or in combination to generate mutants K7A, Q11A, N71A, E111A, N88R, G89R, S90R, K7A/E111A, Q11A/E111A, N71A/E111A, K7A/N71A/E111A, Q11A/N71A/E111A, and K7A/Q11A/N71A/E111A. Out of these, eight mutants, K7A, Q11A, N71A, S90R, E111A, Q11A/E111A, N71A/E111A, and K7A/N71A/E111A, showed an ability to evade RI more than the wild type HPR, with the triple mutant K7A/N71A/E111A having the maximum RI resistance. As a result, these variants exhibited higher cytotoxic activity than wild type HPR. The mutation of Gly-89 in HPR produced no change in the sensitivity of HPR for RI, whereas it has been reported that mutating the equivalent residue Gly-88 in RNase A yielded a variant with increased RI resistance and cytotoxicity. Hence, despite its considerable homology with RNase A, HPR shows differences in its interaction with RI. We demonstrate that interaction between human pancreatic ribonuclease and RI can be disrupted by mutating residues that are involved in HPR-RI binding. The inhibitor-resistant cytotoxic HPR mutants should be useful in developing therapeutic molecules.     

Second derivative of the finger arterial pressure waveform: an insight into dynamics of the peripheral arterial pressure pulse

The study investigated second derivative of the finger arterial pressure waveform (SDFAP) in 120 healthy middle-aged subjects and in 24 subjects with essential hypertension. SDFAP consists of 5 sequential waves 'a'-'e'. Their normalized magnitudes (B/A, C/A, D/A, and E/A) were calculated. In multivariate regression analysis, B/A and C/A correlated only with age. D/A independently correlated with age, heart period, mean blood pressure (MBP), body height, and gender. E/A independently correlated with age and MBP. D/A and E/A were higher (0.42+/-0.16 vs. 0.33+/-0.14, p = 0.05 and 0.63+/-0.15 vs. 0.45+/-0.14, p < 0.001), while B/A and C/A were lower (1.04+/-0.16 vs. 1.20+/-0.17, p = 0.002 and 0.09+/-0.15 vs. 0.26+/-0.20, p = 0.001) in hypertensives compared to sex- and age-matched controls. After the adjustment for MBP, heart period, and body mass index (ANCOVA), independent discriminative power was preserved only for indices B/A and C/A (p = 0.001 and 0.021, respectively). Therefore, B/A and C/A provide additional information about simple clinical characteristics and might reflect the structural alteration of the arterial wall in hypertensive subjects.     

Genetic basis of influenza virus virulence: gene composition and virulence of reassortants between mouse-adapted and nonadapted strains from different subtypes

Reassortment analysis of the pneumovirulence for mice marker of influenza virus has been performed. The original A/USSR/90/77 (H1H1) influenza virus strain or its mouse-adapted variant were crossed with a variant of A/Aichi/2/68 (H3N2) influenza virus highly virulent for mice. The reassortant having HA gene of the original A/USSR/90/77 virus and the other genes of the highly virulent A/Aichi/2/68 strain was avirulent for mice, whereas a similar reassortant possessing HA gene of the mouse-adapted A/USSR/90/77 strain was as virulent as A/Aichi/2/68 parent virus. The reasortant having HA and M genes of A/Aichi/2/68 and other genes of the mouse-adapted A/USSR/90/77 was moderately virulent, resembling in this respect the latter parent. The data indicates that changes in the different genes in course of viral adaptation to mice result in a differential acquisition of virulence for mice.     

Sequential mutations in the NS genes of influenza virus field strains.

The complete nucleotide sequences of the NS genes from three human influenza viruses, A/FM/1/47 (H1N1), A/FW/1/50 (H1N1), and A/USSR/90/77 (H1N1), were determined. Only five single-base differences were found within the sequences of the A/FW/1/50 and A/USSR/90/77 NS genes, thus confirming earlier data suggesting that the 1977 H1N1 viruses are closely related to virus strains that were circulating around 1950. Comparison of all three sequences with those from A/PR/8/34 and A/Udorn/72 viruses illustrates that these genes (with the exception of that of the A/USSR/90/77 strain) evolve through cumulative base changes along a single common lineage. A nucleotide sequence variation of approximately 2.2 to 3.4% per 10 years was determined for the NS gene segments. Extensive size variation was also observed among the NS1 proteins of the various human viruses. The A/FM/1/47 NS1 protein, which consists of 202 amino acids, is 15% shorter than the A/Udorn/72 NS1 protein, which consists of 237 amino acids.     

Antigenic anachronism of influenza viruses A(H2N2) in Leningrad in 1980. II. The laboratory characteristics of influenza A/Leningrad/80 viruses

As indicated by the results of the hemagglutination inhibition (HAI) test, influenza viruses A/Leningrad/80 contain hemagglutinin (HA), similar to that of virus A/Singapore/1/57 (H2N2). Neuraminidase contained in viruses A/Leningrad/80 belongs to serological subtype N2 and is similar to that of virus A/Singapore/1/57 (H2N2). No differences in the polypeptide composition of the virus-induced proteins of viruses A/Leningrad/527/80, A/Leningrad/549/80, A/Leningrad/553/80 and virus A/Singapore/1/57 used as reference have been detected in the study of their electrophoretic mobility in polyacrylamide gel, as well as the mobility of duplexes obtained by the hybridization of the virion and complement RNA of viruses A/Leningrad/553/80 and A/Singapore/1/57. The results of the HAI test with antisera to purified HA indicate that virus A/Leningrad/549/80 contains HA similar to that of viruses A(H2N2) isolated in 1957, but not in 1964. The HAI test with the sera of polecats having the infection permits the differentiation of viruses A/Leningrad/80 from epidemic viruses A(H2N2) isolated in 1957-1965, including reference virus A/Singapore/1/57. In relation to the latter, the isolates of 1980 are older antigenic mutants. The isolates of 1980 are distinguished from virus A(H2N2), isolated in 1975 from the system of persisting influenza infection in a tissue culture, by mutation in NS-gene and the properties of RNA-polymerase. The authenticity of the isolation of viruses A(H2N2) in Leningrad in 1980 has been proved.     

碱性盐胁迫对葡萄种间杂交育种F1代光系统活性的影响

以左山一葡萄(Vitis amurensis cv. ‘Zuoshan1’)为母本、SO4为父本杂交的4个子代株系(A11、A14、A15和A17)为实验材料, 以砧木1103Paulsen (1103P, 耐碱性较强)以及欧亚栽培品种Crimson (V. vinifera cv. ‘Crimson’) (Crimson的耐碱性强于砧木1103P)为参照, 通过测定葡萄叶片PSI及PSII荧光参数, 分析葡萄种间杂交砧木育种F₁代光系统活性对100mmol·L^–1 NaHCO₃的响应。结果表明, NaHCO₃胁迫下, 随着处理时间的延长, Crimson、A15和A14的最大光化学效率(F_v/F_m)、光化学淬灭系数(qP)、光下最大光化学效率(F_v'/F_m')及最大P700荧光产量(P_m)降低幅度较小, 非调节性能量耗散(Y(NO))升高幅度也较小, 调节性能量耗散(Y(NPQ))升高幅度较大; 而A11、A17与砧木1103P各荧光参数变化相近, 其F_v/F_m、qP、F_v'/F_m'及P_m的值降低幅度与Y(NO)升高幅度均较大。进一步分析显示, NaHCO₃胁迫8天后, A15和A14的环式电子传递速率(ETR(I)–ETR(II))维持在较高水平, 缓解了碱性盐胁迫对光系统活性的抑制。各荧光参数指标的主成分分析结果表明, A15的耐碱性较强, A14与Crimson的耐碱性中等, A11、A17与1103P的耐碱性较弱, 耐性分级结果与前期依据生物量所得分级结果一致。     

On the size and the role of a free cytosolic pool of acidic ribosomal proteins in yeast Saccharomyces cerevisiae

A small but distinct amount of yeast acidic ribosomal proteins A1/A2 was detected in cytosol by immunoblotting on a two-dimensional gel electrophoretogram, while 38 kDa acidic protein A0 was not detected. The free forms of A1/A2 in the cytosol were eluted in gel filtration at the molecular mass of about 30 kDa under non-denaturation conditions, suggesting that they exist as a dimer or timer without association with A0. The amount of free A1/A2 was determined by immunoblotting to be 0.3% of the ribosome-bound A1/A2 in yeast. The time course of incorporation of radioactive amino acid showed that the cytosolic free A1/A2 are labeled more rapidly with high specific radioactivity than the ribosome-bound A1/A2. This result suggested that some of the cytosolic A1/A2, if not all, are newly-synthesized proteins which are ready for incorporation into cytoplasmic ribosomes.     

N-glycosylation of CRF receptor type 1 is important for its ligand-specific interaction

The corticotropin-releasing factor (CRF) receptor type 1 (CRFR1) contains five potential N-glycosylation sites: N38, N45, N78, N90, and N98. Cells expressing CRFR1 were treated with tunicamycin to block receptor glycosylation. The nonglycosylated receptor did not bind the radioligand and had a decreased cAMP stimulation potency in response to CRF. To determine which of the polysaccharide chain(s) is/are involved in ligand interaction, the polysaccharide chains were deleted using site-directed mutagenesis of the glycosylation consensus, N-X-S/T. Two sets of mutations were performed for each glycosylation site: N to Q and S/T to A, respectively. The single mutants Q38, Q45, Q78, Q90, Q98, A40, A47, A80, A92, and A100 and the double mutants A40/A47 and A80/A100 were well expressed, bound CRF, sauvagine (SVG), and urotensin-I (UTS-I) with a normal affinity, and increased cAMP accumulation with a high efficiency. In contrast, the combined mutations A80/A92/A100, A40/A80/A92/A100, and A40/A47/A80/A92/A100 had low levels of expression, did not bind the radioligand, and had a decreased cAMP stimulation. These data indicate the requirement for three or more polysaccharide chains for normal CRFR1 function.     

Effects of glyphosate on nitrogen fixation of free-living heterotrophic bacteria

The effect of the herbicide glyphosate ( N -(phosphonomethyl)glycine) on the growth, respiration and nitrogen fixation of Azotobacter chroococcum and A. vinelandii was studied. Azotobacter vinelandii was more sensitive to glyphosate toxicity than A. chroococcum. Recommended dosages of glyphosate did not affect growth rates. More than 4 kg ha^-1 is needed to find some inhibitory effect. Specific respiration rates were 19.17 mmol O₂ h^-1 g^-1 dry weight for A. chroococcum and 12.09 mmol h^-1 g^-1 for A. vinelandii. When 20 kg ha^-1 was used with A. vinelandii , respiration rates were inhibited 60%, the similar percentage inhibition A. chroococcum showed at 28 kg ha^-1. Nitrogen fixation dropped drastically 80% with 20 kg ha^-1 in A. vinelandii and 98% with 28 kg ha^-1 in A. chroococcum. Cell size as determined by electron microscopy decreased in the presence of glyphosate, probably because glyphosate induces amino acid depletion and reduces or stops protein synthesis.     

甲型H1N1流感病毒在季流病毒、禽流感病毒共感染时变异可能性的验证

目的 甲型H1N1流感病毒A/California/7/2009分别与A/Brisbane/10/07和A/ShenZhen/406H/06共感染小型香猪,预测甲流病毒在与季流H3N2病毒/甲流病毒与禽流感病毒共感染时是否会发生变异.方法 分别将A/California/7/2009(CA7)与A/Brisbane/10/07(H3N2),A/California/7/2009与A/Shenzhen/406H/06(H5N1)对5～6月龄小型猪共感染,小型猪经复方氯胺酮0.1 mL/kg麻醉后进行滴鼻感染,感染后第5天安乐死动物,取动物肺组织作病毒测序分析.结果 A/California/7/2009(CA7)与A/Brisbane/10/07(H3N2)共感染后,A/California/7/2009病毒PB1基因993位G→A突变,PA基因1659位G→A突变,没有氨基酸的变异.A/California/7/2009与A/Shenzhen/406H/06(H5N1)共感染后A/California/7/2009病毒PB2基因1711位T→C突变.碱基的突变未引起氨基酸的变异.结论 A/California/7/2009(CA7)与A/Brisbane/10/07(H3N2),A/California/7/2009与A/Shenzhen/406H/06(H5N1)共感染后在猪的体内没有发生病毒重组、变异.     

枯草蛋白酶E的定点突变及其对酶性质的影响

用定点突变的方法研究S221C/P225A,N118S/S221C/P225A,D60N/S221C/P225A和Q103R/S221C/P225A突变对蛋白酶活性,酯酶活性与蛋白酶活性之比的影响。结果表明：S221C/P225A突变使蛋白酶活性比枯草蛋白酶E低73000多倍,酯酶活性与蛋白酶活性之比是Subtiligase的3倍;N118S/S221C/P225A突变使蛋白酶活性和酯酶活性分别比S221C/P225A突变下降3.6倍和15倍,酯酶与蛋白酶活性之比下降4倍,同时增加变体酶的热稳定性;D60N/N118S/S221C/P225A突变使蛋白酶活性比N118S/S221C/P225A突变体下降15倍,但对酯酶活性几乎没有影响,酯酶与蛋白酶活性之比增加14倍,分别是S221C/P225A突变体和Subtiligase的3.3倍和10.3倍;但是,Q103R/N118S/S221C/P225A突变使蛋白酶活性比N118S/S221C/P225A突变体增加5倍,酯酶活性下降55倍,酯酶与蛋白酶活性之比下降1000倍。     

Left cleft lip predominance and genetic similarities of L line and CL/Fr strain mice

Newborn litters of the L line and CL/Fr and A/JFr strains were examined, and sex, frequency and type of cleft lip (left, right or bilateral) were recorded. Embryos and fetuses from crosses between these strains and line were collected on days 13 to 16 of gestation, and frequency and type of cleft lip recorded. Overall cleft frequencies in L X CL/Fr, CL/Fr X L, and CL/Fr X A/JFr crosses (female stated first) were similar, while in A/JFr X L (10.3%) they were significantly lower than in L X A/JFr (23.3%). The data suggested that the same maternal effect genes were present in CL/Fr and the related L line and absent from A/JFr. In the L, CL/Fr, and A/JFr newborns, there was a tendency for males to have higher frequencies of cleft lip and bilateral cleft lip and the latter was significant for L. Left cleft lip frequency was significantly higher than right for L and CL/Fr newborns and in embryos of the CL/Fr X L and L X CL/Fr cross. No significant differences in laterality were found in the A/JFr strain, A/JFr X L, L X A/JFr, and CL/Fr X A/JFr crosses. It was concluded that (1) the embryonic and maternal effect genes for cleft lip are similar or identical in CL/Fr and L; and (2) using data from the literature, there are additional genetic factor(s) increasing left cleft lip occurrence acting in the embryo, which are present in CL/Fr, L, A/HeJ, A/He, and A/St and absent from A/JKt, A/J, A/JFr, and A/WySn.     

The S segment of Punta Toro virus (Bunyaviridae, Phlebovirus) is a major determinant of lethality in the Syrian hamster and codes for a type I interferon antagonist

Two strains of Punta Toro virus (PTV), isolated from febrile humans in Panama, cause a differential pathogenesis in Syrian hamsters, which could be a useful model for understanding the virulence characteristics and differential outcomes in other phleboviral infections such as Rift Valley fever virus. Genetic reassortants produced between the lethal Adames (A/A/A) and nonlethal Balliet (B/B/B) strains were used in this study to investigate viral genetic determinants for pathogenesis and lethality in the hamster model. The S segment was revealed to be a critical genome segment, determining lethality with log(10) 50% lethal doses for each PTV genotype as follows (L/M/S convention): A/A/A, <0.7; B/A/A, <0.7; A/B/A, 1.5; B/B/A, 2.2; B/A/B, 4.7; A/B/B, >4.7; A/A/B, >4.7; B/B/B, >4.7. In addition, the Adames strain inhibits the induction of alpha/beta interferon (IFN-alpha/beta) in vivo and in vitro and inhibits the activation of the IFN-beta promoter. Expression of the PTV Adames NSs protein, encoded by the S RNA segment, inhibited the virus-mediated induction of an IFN-beta promoter-driven reporter gene, suggesting that PTV NSs functions as a type I IFN antagonist. Taken together, these data indicate a mechanism of pathogenesis in which the suppression of the type I IFN response early during PTV infection leads to early and uncontrolled viral replication and, ultimately, hamster death. This study contributes to our understanding of Phlebovirus pathogenesis and identifies potential targets for immune modulation to increase host survival.     

Prevalence of Antibody to Current Influenza Viruses and Effect of Vaccination on Antibody Response

The extent of antibody to the influenza virus A/Hong Kong/68 (H3N2) after four years of prevalence was investigated in Britain and in the U.S.A. The results indicated a high incidence in both populations. The prevalence of antibody to a variant A/England/42/72 (H3N2) which has been causing epidemics of influenza in the southern hemisphere during the middle months of 1972 was also investigated. The differences reflect the shift in antigenic content of this variant, and although the overall proportion of the sera with antibody at > 1/40 was 37%, some age groups had an incidence of only 20% or less with antibody at this level. A commercial inactivated A/Hong Kong/68 influenza vaccine was given to a group of volunteers in Britain to see how effective it might be in stimulating antibody to the variant A/England/42/72. The antibody responses were better than expected from earlier vaccine studies, and 63% of the vaccinees developed antibody to the A/England/42/72 to levels thought likely to be protective. This suggested that until a vaccine made with the variant A/England/42/72 becomes available the present A/Hong Kong/68 vaccine would be of use to protect those at special risk this winter.     

Heterochromatin characterization of sex chromosomes in Triturus marmoratus (Urodela, Salamandridae).

The sex chromosomes of the Iberian marbled newt, Triturus marmoratus, were studied using various banding techniques, including restriction enzyme/nick translation (RE/NT) procedures. Four types of heterochromatin on the sex chromosomes could be distinguished: (1) distamycin A/DAPI and chromomycin A3/distamycin A positive, EcoRI/NT negative, and HaeIII/NT and HinfI/NT positive; (2) distamycin A/DAPI and chromomycin A3/distamycin A positive, but RE/NT negative; (3) AT rich, but RE/NT negative; and (4) distamycin A/DAPI and chromomycin A3/distamycin A positive, EcoRI/NT and HinfI/NT negative, but HaeIII/NT positive. These data suggest a common origin for the terminal heterochromatic domains of both the X and Y chromosomes in this species.