Autophagy is a conserved pathway for the bulk degradation of cytoplasmic components in all eukaryotes. This process plays a critical role in the adaptation of plants to drastic changing environmental stresses such as starvation, oxidative stress, drought, salt, and pathogen invasion. This paper summarizes the current knowledge about the mechanism and roles of plant autophagy in various plant stress responses.
Adaptation, Physiological ; Arabidopsis ; genetics ; physiology ; Arabidopsis Proteins ; genetics ; metabolism ; Autophagy ; genetics ; Disease Resistance ; Plant Diseases ; immunology ; Saccharomyces cerevisiae ; genetics ; Sequence Homology ; Stress, Physiological

Yeast Elongation protein 3 (yElp3), the catalytic subunit of the multi-subunit histone acetyltransferase elongator complex, is involved in histone acetylation and transcription, exocytosis and tRNA modification. To study the complex function of yElp3 in yeast, we amplified the yElp3 gene fragment encoding 73aa in the N-terminal from plasmid pYES2-yElp3, and then cloned it into pMXB10 to construct the recombinant plasmid pMXB10-yElp3-219. We expressed the fusion protein in E. coli BL21 (DE3), then purified it by chin affinity column, and finally obtained the soluble purified protein (8.0 kD), which was used to immune the rabbits for acquiring antiserum. ELISA and Western blotting indicated that the polyclonal antibody was of high titration and specificity. Chromatin immunoprecipitation (ChIP) assay with this antibody suggested that yhElp3 exerted the transcriptional regulatory function directly through its presence on the SSA3 gene; this might be the reason that it can rescue the delay activation of SSA3 in elp3delta cells.
Amino Acid Sequence ; Antibodies ; analysis ; immunology ; Escherichia coli ; genetics ; metabolism ; Gene Expression Regulation, Fungal ; Histone Acetyltransferases ; biosynthesis ; genetics ; immunology ; Molecular Sequence Data ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Saccharomyces cerevisiae Proteins ; biosynthesis ; genetics ; immunology

The Yellow Fever (YF) vaccine, an attenuated yellow fever 17D (YF-17D) live vaccine, is one of the most effective and safest vaccines in the world and is regarded as one of the best candidates for viral expression vector. We here first reported in China the construction and characterization of the recombinant expression vector of yellow fever 17D which contained the proteinase 2A fragment of foot-and-mouth disease virus (FMDV). Three cDNA fragments representing the full-length YF-17D genome, named 5'-end cDNA (A), 3'-end cDNA (B) and middle cDNA (C), were obtained by reverse transcription polymerase chain reaction (RT-PCR), together with the introduction of SP6 enhancer, necessary restriction sites and overlaps for homologous recombination in yeast. Fragment A and B were then introduced into pRS424 in turn by DNA recombination, followed by transfection of fragment C and the recombinant pRS424 containing A and B (pRS-A-B) into yeast. A recombinant vector containing full length cDNA of YF-17D (pRS-YF) was obtained by screening on medium lack of tryptophan and uracil. A recombinant YF-17D expression vector containing FMDV-2A gene fragment (pRS-YF-2A1) was then constructed by methods of DNA recombination and homologous recombination in yeast described above. In vitro transcription of the recombinant vector pRS-YF-2A1 was then carried out and introduced into BHK-21 cells by electroporation. Results of indirect immunofluorescence assay (IFA) and titer determination showed a stable infectious recombinant virus was gotten, whose features such as growth curve were similar to those of the parental YF-17D. The results suggest that the recombinant vector pRS-YF-2A1, by introduction of heterogenous genes via 2A region, is potential to be an effective live vaccine expression vector.
Animals ; Cell Line ; Cloning, Molecular ; Cricetinae ; Epitopes ; immunology ; Foot-and-Mouth Disease ; prevention & control ; Foot-and-Mouth Disease Virus ; genetics ; immunology ; Genetic Engineering ; Genetic Vectors ; Recombination, Genetic ; Saccharomyces cerevisiae ; genetics ; metabolism ; Vaccines, Attenuated ; Viral Vaccines ; genetics ; immunology ; Yellow fever virus ; genetics ; immunology

OBJECTIVETo introduce exponent curve model methods in the study of the hepatitis B vaccine antibody level.

METHODSAfter the China made vaccine of hepatitis B DNA recombinant yeast derived vaccine (YDV) had been carried out for 5 years, data on the anti-HBsAg's titer were used to construct an exponent curve model. When the vaccination program had been carried out for 8 years, the predicating results of the model were further tested by observed number.

RESULTSThe exponent curve model was Y = 165.67 exp (-0.019X) and the R(2) was 0.98. After 8 years, the practical observed number became 35 mIU/ml, and the predicating result of the model was 27 mIU/ml, 8 mIU/ml lower than the observed number. When the vaccine had been carried out for 12 years, the predicating results of the model became 10.74 mIU/ml, still higher than 10 mIU/ml but was still in the effective range.

CONCLUSIONAn exponent curve model could be constructed, as long as the data of the antibody's titer was in accordance with the tendency of exponent curve. The model could be used to predict the persistence lever of vaccine antibody under certain conditions. The results showed that after 8 years, the predicting results of the model were reliably lower than the observed number.

Follow-Up Studies ; Hepatitis B ; immunology ; prevention & control ; Hepatitis B Antibodies ; blood ; Hepatitis B Vaccines ; immunology ; Humans ; Models, Biological ; Saccharomyces cerevisiae ; genetics ; Vaccination ; Vaccines, DNA ; immunology ; Vaccines, Synthetic ; immunology

We previously induced protective immune response by oral immunization with yeast expressing the ApxIIA antigen. The ApxI antigen is also an important factor in the protection against Actinobacillus pleuropneumoniae serotype 5 infection; therefore, the protective immunity in mice following oral immunization with Saccharomyces cerevisiae expressing either ApxIA (group C) or ApxIIA (group D) alone or both (group E) was compared with that in two control groups (group A and B). The immunogenicity of the rApxIA antigen derived from the yeast was confirmed by a high survival rate and an ApxIA-specific IgG antibody response (p < 0.01). The highest systemic (IgG) and local (IgA) humoral immune responses to ApxIA and ApxIIA were detected in group E after the third immunization (p < 0.05). The levels of IL-1beta and IL-6 after challenge with an A. pleuropneumoniae field isolate did not change significantly in the vaccinated groups. The level of TNF-alpha increased in a time-dependent manner in group E but was not significantly different after the challenge. After the challenge, the mice in group E had a significantly lower infectious burden and a higher level of protection than the mice in the other groups (p < 0.05). The survival rate in each group was closely correlated to the immune response and histopathological observations in the lung following the challenge. These results suggested that immunity to the ApxIA antigen is required for optimal protection.
Actinobacillus Infections/prevention & control ; Actinobacillus pleuropneumoniae/genetics/*immunology ; Animals ; Antibodies, Bacterial/blood ; Bacterial Proteins/analysis/*immunology ; Cytokines/analysis/blood ; Disease Models, Animal ; Female ; Hemolysin Proteins/analysis/*immunology ; Immunoglobulin A/blood/immunology ; Intestines/immunology ; Lung/cytology/immunology ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins/*immunology ; Saccharomyces cerevisiae/*genetics/immunology ; Survival Analysis ; Time Factors ; Vaccination ; Vaccines, Synthetic/administration & dosage/*immunology

Knowledge of simulated microgravity (SMG)-induced changes in the pathogenicity of microorganisms is important for success of long-term spaceflight. In a previous study using the high aspect ratio vessel bioreactor, we showed that the yeast species Saccharomyces cerevisiae underwent a significant phenotypic response when grown in modeled microgravity, which was reflected in the analysis of gene expression profiles. In this study, we establish that Candida albicans responds to SMG in a similar fashion, demonstrating that there is a conserved response among yeast to this environmental stress. We also report that the growth of C. albicans in SMG results in a morphogenic switch that is consistent with enhanced pathogenicity. Specifically, we observed an increase in filamentous forms of the organism and accompanying changes in the expression of two genes associated with the yeast-hyphal transition. The morphological response may have significant implications for astronauts' safety, as the fungal pathogen may become more virulent during spaceflight.
Candida albicans ; cytology ; genetics ; growth & development ; pathogenicity ; Candidiasis ; immunology ; Cell Polarity ; Cells, Cultured ; Fungal Proteins ; genetics ; Gene Expression Regulation, Fungal ; Humans ; Microscopy, Fluorescence ; RNA, Fungal ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Saccharomyces cerevisiae ; cytology ; genetics ; growth & development ; Virulence ; Weightlessness Simulation

Oral vaccination may be the most efficient way of inducing an immune response at the remote mucosal site through the common mucosal immune network. Antigenspecific secretory IgA (sIgA) is the major immunoglobulin type generally detected in the secretions of experimental animals following an effective oral immunization. Actinobacillus pleuropneumoniae causing disease in the lung of pig initially interacts, colonizes, and infects the host tissues at the mucosal surface of the respiratory tract. Also, importantly for A. pleuropneumoniae protection, the quantity of sIgA in the lung had merits associated with the mucosal immunity. However, there is no simple method to monitor the level of sIgA as an indicator for the induction of local immune responses by an oral vaccination in the target tissue. Therefore, the relationship between sIgA and IgG was analyzed to evaluate the induction of local immune responses by an oral immunization with Saccharomyces cerevisiae expressing the apxIA and apxIIA genes of A. pleuropneumoniae in this study. The correlation coefficient of determination (r2 x 100) for paired samples in both vaccinated and control groups showed a significant positive-relationship between IgG in sera and sIgA in the lung or intestine. These results indicated that IgG antibody titers in sera could be useful to indirectly predict local immune response, and sIgA, in the lung or intestine to evaluate the efficacy of an oral vaccination.
Actinobacillus pleuropneumoniae ; Administration, Oral ; Animals ; Antigens, Fungal/*immunology ; Bacterial Proteins/genetics/immunology ; Bacterial Vaccines/*immunology ; Disease Models, Animal ; Female ; Hemolysin Proteins ; Immunity, Mucosal/*immunology ; Immunoglobulin A, Secretory/*analysis ; Immunoglobulin G/*blood ; Intestine, Small/immunology ; Lung/immunology ; Mice ; Mice, Inbred BALB C ; Saccharomyces cerevisiae/*immunology

OBJECTIVETo compare the intervention effects of four traditional Chinese medicines (TCMs) with typical cold or hot property on body temperature and temperature-sensitive transient receptor potential ion channel proteins (TRPs) of rats with yeast-induced fever.

METHODThe pyrexia model was induced by injecting yeast suspension subcutaneously. Totally 108 male SD rats were randomly divided into the normal group, the model group, the Rhei Radix et Rhizoma treated group, the Coptidis Rhizoma treated group, the Euodiae Fructus treated group, and the Alpiniae Officinarum Rhizoma treated group, with 18 rats in each group. At the 4 h, 8 h and 12 h after injection of yeast, the rats were sacrificed to collect their hypothalamus and dorsal root ganglion. The expressions of TRPV1 and TRPM8 were detected by immunohistochemistry and Western blot method.

RESULTCompared with the normal group, after injection of yeast, the temperature of rats in the model group notably increased, and reached the peak at 8 h (P < 0.01). The TRPV1 level in hypothalamus and dorsal root ganglia (DRG) of the model group significantly increased, whereas the TRPM8 level significantly reduced. Compared with the model group, the Rhei Radix et Rhizoma group and the Coptidis Rhizoma group showed significant decrease in the high body temperature of rats caused by yeast, down-regulation in the expression of TRPV1, and up-regulation in the expression of TRPM8 (P < 0.05 or P < 0.01). Euodiae Fructus and Alpiniae Officinarum Rhizoma had no significant effect on either temperature or TRPs of fever rats.

CONCLUSIONRhei Radix et Rhizoma and Coptidis Rhizoma, both are TCMs with cold property, can reduce the temperature of fever rats induced by yeast, which may be related to their effective regulation of TRPV1 and TRPM8 in hypothalamus and DRG, while Euodiae Fructus and Alpiniae Officinarum Rhizoma had no relevant effect.

Animals ; Antipyretics ; administration & dosage ; chemistry ; Body Temperature Regulation ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; chemistry ; Fever ; drug therapy ; immunology ; microbiology ; physiopathology ; Gene Expression Regulation ; drug effects ; Humans ; Male ; Rats ; Rats, Sprague-Dawley ; Saccharomyces cerevisiae ; immunology ; TRPM Cation Channels ; genetics ; immunology ; TRPV Cation Channels ; genetics ; immunology

OBJECTIVETo investigate the immunological function of a yeast expression system for thymosin alpha1 (Talpha1).

METHODSA constructed Talpha1 yeast expression system was used to investigate the immunological function of orally administered Talpha1. Dried yeast containing three different concentration of Talpha1 was fed to normal Balb/c mice and other Balb/c mice whose immunities were inhibited in advance by cyclophosphamide. Synthesized Talpha1 peptide was used as positive control and dried yeast with empty plasmid was used as negative control. CD4(+) and CD8(+) levels were detected by flow cytometry assay. TNF-alpha, IFN-gamma, IL-2, IL-6 and IL-10 levels were detected by liquid chip.

RESULTSIn normal Balb/c mice or immune inhibition Balb/c mice, CD8(+) levels were significantly increased. Especially in immune inhibition Balb/c mice, CD8(+) levels in synthesized Talpha1 group (18.77%+/-4.72%), small dose group (13.48%+/-6.17%) and large dose group (22.74%+/-1.09%) were significantly higher than that in empty yeast control group (7.49%+/-2.14%).

CONCLUSIONOrally administered Talpha1 has its certain immunomodulatory function.

Administration, Oral ; Animals ; CD4-Positive T-Lymphocytes ; drug effects ; CD8-Positive T-Lymphocytes ; drug effects ; Cyclophosphamide ; toxicity ; Cytokines ; metabolism ; Immunologic Deficiency Syndromes ; chemically induced ; drug therapy ; immunology ; Immunologic Factors ; administration & dosage ; genetics ; Immunosuppressive Agents ; toxicity ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins ; administration & dosage ; genetics ; Saccharomyces cerevisiae ; genetics ; Thymosin ; administration & dosage ; analogs & derivatives