Structure of the gene of tum- transplantation antigen P91A: the mutated exon encodes a peptide recognized with Ld by cytolytic T cells

Mutagen treatment of mouse P815 tumor cells produces immunogenic mutants that express new transplantation antigens (tum- antigens) recognized by cytolytic T cells. We found that the gene conferring expression of tum- antigen P91A contains 12 exons, encoding a 60 kd protein lacking a typical N-terminal signal sequence. The sequence shows no significant similarity with sequences in current data bases. A mutation that causes expression of the antigen is located in exon 4; it is the only apparent difference between the normal and the antigenic alleles. A short synthetic peptide corresponding to a region of exon 4 located around this mutation makes P815 cells sensitive to lysis by anti-P91A cytolytic T cells. The mutation creates a strong aggretope enabling the peptide to bind the H-2 Ld molecule. Several secondary tumor cell variants that no longer express tum- antigen P91A were found to carry deletions in the gene.     

Molecular cloning and characterization of fox testis kinectin

Kinectin was isolated and characterized from a fox testis cDNA library using a monoclonal antibody (FTA-1) raised against testis surface proteins. The cDNA sequence of 4,479 nucleotides encodes an ORF of 1,330 amino acids (aa) with high homology to mouse, human, and chicken kinectins (GenBank Accession Number AF095786). Southern analysis was used to show that genes homologous to kinectin are present in several mammal species and in at least one marsupial, but not in bacteria. Alternatively spliced forms of fox kinectin were identified, and one of these is uniquely expressed in brain and spleen tissues. Kinectin expression was highest in testis relative to other tissues examined. Sequence analysis and comparisons between species revealed that kinectin encodes multiple alpha-helical coiled coils predicted to form dimers, and is, therefore, likely to exist as a dimer. The results presented in this article suggest that kinectin is required for spermatogenesis, but is not a likely candidate for use in immunocontraceptive vaccines.     

Increased heat requirement for leaf flushing in temperate woody species over 1980–2012: effects of chilling,precipitation and insolation

Recent studies have revealed large unexplained variation in heat requirement‐based phenology models, resulting in large uncertainty when predicting ecosystem carbon and water balance responses to climate variability. Improving our understanding of the heat requirement for spring phenology is thus urgently needed. In this study, we estimated the species‐specific heat requirement for leaf flushing of 13 temperate woody species using long‐term phenological observations from Europe and North America. The species were defined as early and late flushing species according to the mean date of leaf flushing across all sites. Partial correlation analyses were applied to determine the temporal correlations between heat requirement and chilling accumulation, precipitation and insolation sum during dormancy. We found that the heat requirement for leaf flushing increased by almost 50% over the study period 1980–2012, with an average of 30 heat units per decade. This temporal increase in heat requirement was observed in all species, but was much larger for late than for early flushing species. Consistent with previous studies, we found that the heat requirement negatively correlates with chilling accumulation. Interestingly, after removing the variation induced by chilling accumulation, a predominantly positive partial correlation exists between heat requirement and precipitation sum, and a predominantly negative correlation between heat requirement and insolation sum. This suggests that besides the well‐known effect of chilling, the heat requirement for leaf flushing is also influenced by precipitation and insolation sum during dormancy. However, we hypothesize that the observed precipitation and insolation effects might be artefacts attributable to the inappropriate use of air temperature in the heat requirement quantification. Rather than air temperature, meristem temperature is probably the prominent driver of the leaf flushing process, but these data are not available. Further experimental research is thus needed to verify whether insolation and precipitation sums directly affect the heat requirement for leaf flushing.     

Smoke aldehyde component influences pulmonary edema.

The pulmonary edema of smoke inhalation is caused by the toxins of smoke and not the heat. We investigated the potential of smoke consisting of carbon in combination with either acrolein or formaldehyde (both common components of smoke) to cause pulmonary edema in anesthetized sheep. Seven animals received acrolein smoke, seven animals received a low-dose formaldehyde smoke, and five animals received a high-dose formaldehyde smoke. Pulmonary arterial pressure, pulmonary capillary wedge pressure, and cardiac output were not affected by smoke in any group. Peak airway pressure increased after acrolein (14 +/- 1 to 21 +/- 2 mmHg; P less than 0.05) and after low- and high-dose formaldehyde (14 +/- 1 to 21 +/- 1 and 20 +/- 1 mmHg, respectively; both P less than 0.05). The partial pressure of O2 in arterial blood fell sharply after acrolein [219 +/- 29 to 86 +/- 9 (SE) Torr; P less than 0.05] but not after formaldehyde. Only acrolein resulted in a rise in lung lymph flow (6.5 +/- 2.2 to 17.9 +/- 2.6 ml/h; P less than 0.05). Lung lymph-to-plasma protein ratio was unchanged for all three groups, but clearance of lymph protein was increased after acrolein. After acrolein, the blood-free extravascular lung water-to-lung dry weight ratio was elevated (P less than 0.05) compared with both low- and high-dose formaldehyde groups (4.8 +/- 0.4 to 3.3 +/- 0.2 and 3.6 +/- 0.2, respectively). Lymph clearance (ng/h) of thromboxane B2, leukotriene B4, and the sulfidopeptide leukotrienes was elevated after acrolein but not formaldehyde.(ABSTRACT TRUNCATED AT 250 WORDS)     

Degradation of 4-hydroxyphenylacetate by Xanthobacter 124X

Xanthobacter 124X when grom on 4-hydroxyphenylacetate was able to hydroxylate this compound yielding homogenisate. Ring fission of this latter compound gave maleylacetoacetate which was isomerized to fumarylacetoacetate. The isomerase involved resembled maleylacetoacetate isomerases in Gram-negative bacteria in that glutathione was required for activity. Fumarate and acetoacetate were both detected as products of the hydrolysis of fumarylacetoacetate.     

Study of the dynamics of neutralization escape mutants in a chimpanzee naturally infected with the simian immunodeficiency virus SIVcpz-ant.

Here we report on the use of spectral map analysis of time-paired sequential neutralization data of 11 serum samples of a chimpanzee naturally infected with a simian immunodeficiency virus (SIVcpz-ant) and 8 primary consecutive SIVcpz-ant isolates, taken at about 4-month intervals. The analysis reveals the existence of three SIVcpz-ant isolate and serum neutralization clusters. Each cluster groups virus isolates and/or sera based on similarities of their neutralization spectra. On average, neutralization escape mutants emerged after 15 months and mounted a neutralization response approximately 8 months later. The entire gp160 regions of eight consecutive isolates were sequenced and analyzed by a new statistical method called polygram, which allowed the deduction of amino acid sequence motifs of gp160 which were specific for SIVcpz-ant isolates belonging to the same isolate neutralization clusters. Changes in specific amino acid quadruplets in V1, V2, C3, V4, V5, and CD4 domains of gp120 and gp40 were seen to correlate with the neutralization clusters with most of the specific changes occurring in the V4 region. This method of analysis may facilitate an understanding of the study of the dynamic interplay between human immunodeficiency virus (HIV) and host neutralization responses as well as providing possible insights into mechanisms of persistence of HIV-1-related lentiviruses in their natural hosts.     

三氧化二砷对食管癌细胞增殖和热休克蛋白70表达的影响

目的：研究三氧化二砷（As2O3）对食管癌细胞增殖和热休克蛋白70（HSP70）表达的影响。方法：通过相差显微镜、流式细胞术、免疫细胞化学染色和免疫印迹分析等方法观察As2O3对人食管癌细胞株EC1的作用效果和作用机制。结果：与对照组相比,经2μmol/L和5μmol/Las2O3作用的细胞出现明显的生长抑制,G2/M期细胞比例增加;2μmol/Las2O3作用48h后经Ecl细胞HSP70（heat shock protein70）及HSC70(heat shock cognate protein70)表达均增加。结论：As2O3诱导食管癌细胞G2/M期阻滞抑制细胞增殖和生长;HSP70的升高是细胞对As2O3作用后出现的应激反应,并与细胞周期阻滞相关。     

Phylogenetics of tribe Sabiceeae (Ixoroideae,Rubiaceae) revisited,with a new subgeneric classification for Sabicea

Tribe Sabiceeae (Ixoroideae, Rubiaceae) has undergone recent taxonomical changes with the incorporation of the related genera Ecpoma, Pseudosabicea and Stipularia into the type genus Sabicea. We use phylogenetic analysis and morphological data to verify the relationships among members of the tribe, including the most comprehensive taxon sampling of the tribe to date with 74 of 145 species. Sequence data from the nuclear internal transcribed spacer (ITS) and three plastid markers (petD, rps16, trnT–F) were used to infer relationships among the members of the tribe. Individual analyses using maximum likelihood, parsimony and Bayesian approaches reveal several supported clades: the former genus Stipularia is resolved as a monophyletic unit, but Ecpoma is monophyletic only if Sabicea urbaniana and Sabicea xanthotricha are included (corresponding to Sabicea subgenus Stipulariopsis sensu Wernham). Pseudosabicea is biphyletic, with one clade corresponding to section Anisophyllae of Hallé (1964) and the other one to the other sections (Floribundae and Sphaericae) of the genus. Eleven morphological characteristics were recorded for all species studied and seven have been mapped onto the phylogenetic tree to study their evolution in the group and assess their value for the classification of Sabicea s.l. Finally, our study shows that a combination of diagnostic characteristics should be used to differentiate each group and we propose to recognise four subgenera in Sabicea.