Centrosomal protein centrin is not detectable during early pre-implantation development but reappears during late blastocyst stage in porcine embryos

Centrin is an evolutionarily conserved 20 kDa, Ca+2-binding, calmodulin-related protein associated with centrioles and basal bodies of phylogenetically diverse eukaryotic cells. Earlier studies have shown that residual centrosomes of non-rodent mammalian spermatozoa retain centrin and, in theory, could contribute this protein for the reconstruction of the zygotic centrosome after fertilization. The present work shows that CEN2 and CEN3 mRNA were detected in germinal vesicle-stage (GV) oocytes, MII oocytes, and pre-implantation embryos from the two-cell through the blastocyst stage, but not in spermatozoa. Boar ejaculated spermatozoa possess centrin as revealed by immunofluorescence microscopy and western blotting. Immature, GV oocytes possess speckles of centrin particles in the perinuclear area, visualized by immunofluorescence microscopy and exhibit a 19 kDa band revealed by western blotting. Mature MII stage oocytes lacked centrin that could be detected by immunofluorescence or western blotting. The sperm centrin was lost in zygotes after in vitro fertilization. It was not detectable in embryos by immunofluorescence microscopy until the late blastocyst stage. Embryonic centrin first appeared as fine speckles in the perinuclear area of some interphase blastocyst cells and as putative centrosomes of the spindle poles of dividing cells. The cells of the hatched blastocysts developed centrin spots comparable with those of the cultured cells. Some blastomeres displayed undefined curved plate-like centrin-labeled structures. Anti-centrin antibody labeled interphase centrosomes of cultured pig embryonic fibroblast cells as distinct spots in the juxtanuclear area. Enucleated pig oocytes reconstructed by electrofusion with pig fibroblasts displayed centrin of the donor cell during the early stages of nuclear decondensation but became undetectable in the late pronuclear or cleavage stages. These observations suggest that porcine zygotes and pre-blastocyst embryonic cells lack centrin and do not retain exogenously incorporated centrin. The early embryonic centrosomes function without centrin. Centrin in the blastocyst stage embryos is likely a result of de novo synthesis at the onset of differentiation of the pluripotent blastomeres.

The role of type I interferon production by dendritic cells in host defense

Type I interferons (IFN) and dendritic cells (DC) share an overlapping history, with rapidly accumulating evidence for vital roles for both production of type 1 IFN by DC and the interaction of this IFN both with DC and components of the innate and adaptive immune responses. Within the innate immune response, the plasmacytoid DC (pDC) are the "professional" IFN producing cells, expressing specialized toll-like receptors (TLR7 and -9) and high constitutive expression of IRF-7 that allow them to respond to viruses with rapid and extremely robust IFN production; following activation and production of IFN, the pDC subsequently mature into antigen presenting cells that help to shape the adaptive immune response. However, like most cells in the body, the myeloid or conventional DC (mDC or cDC) also produce type I IFNs, albeit typically at a lower level than that observed with pDC, and this IFN is also important in innate and adaptive immunity induced by these classic antigen presenting cells. These two major DC subsets and their IFN products interact both with each other as well as with NK cells, monocytes, T helper cells, T cytotoxic cells, T regulatory cells and B cells to orchestrate the early immune response. This review discusses some of the converging history of DC and IFN as well as mechanisms for IFN induction in DC and the effects of this IFN on the developing immune response.

(-)-Epigallocatechin-3-gallate protects mice from concanavalin A-induced hepatitis through suppressing immune-mediated liver injury

(-)-Epigallocatechin-3-gallate (EGCG) is the major active component of green tea. Increasing evidence has suggested that EGCG exhibits anti-inflammatory, anti-oxidant and immunosuppressive effects. In this study, we investigated the effect of EGCG on concanavalin A (ConA)-induced hepatitis (CIH) in mice, a model of immune-mediated liver injury in humans. We pretreated mice with EGCG before ConA injection, and then measured alanine aminotransferase (ALT) levels in plasma, inflammatory infiltration and hepatocyte apoptosis in liver. Potential therapeutic mechanisms were elucidated further by measuring several inflammatory mediators. Mice pretreated with EGCG exhibited much less increased ALT levels in plasma, reduced inflammatory infiltration and hepatocyte apoptosis in liver compared with control mice pretreated with vehicle solutions. We further investigated the mechanisms of the protective effects of EGCG. In EGCG-pretreated mice, we found abrogated tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma at both protein levels in plasma and mRNA levels in liver. At the same time, the concentration of nitrite in plasma and inducible nitric oxide synthase production in liver were both down-regulated in these mice. Moreover, IFN-inducible protein-10 and macrophage inflammatory protein-1alpha expressions in liver were decreased significantly. Therefore, EGCG is capable of regulating immune-mediated liver injury in vivo. The protective effect depended on its suppressive effect on the production of important inflammatory mediators.

Mechanism of neuroprotective effect induced by QingKaiLing as an adjuvant drug in rabbits with E. coli bacterial meningitis

OBJECTIVE

To explore the neuroprotective effects and underlying mechanism of QingKaiLing (QKL) as an adjuvant treatment for bacterial meningitis.

METHOD

E. coli bacterial meningitis rabbits were treated with antibiotics (ampicillin) alone or in combination with QKL. The number of leukocytes and the concentration of protein in the cerebrospinal fluid (CSF) of rabbits were determined at 0, 16, and 26 hours after treatment. Brain water, sodium, potassium, and calcium contents were determined at the 26-hour time point. The level of matrix metalloproteinase-9 in the brain was also determined by Western blot.

RESULT

The average number of leukocytes and the concentration of protein in CSF of the QKL adjuvant treatment group were reduced compared with the ampicillin alone group. Brain water, sodium, and calcium contents were reduced in the QKL adjuvant treatment group. The level of MMP-9 in brain tissue was also reduced in the QKL adjuvant treatment group.

CONCLUSION

QKL adjuvant treatment alleviates the aggravated inflammatory reaction and partially protects brain tissue from antibiotic-induced injury. The mechanism of this neuroprotective effect of QKL may be due to decreased levels of Ca2+ and MMP-9 in the brain.

15-Lipoxygenase is a component of the mammalian sperm cytoplasmic droplet

Lipoxygenases (LOXs) are a family of enzymes capable of peroxidizing phospholipids. A member of the LOX family of enzymes, 15-LOX, participates in the degradation of mitochondria and other organelles within differentiating red blood cells, the reticulocytes. The present study provides biochemical and immunocytochemical evidence for the presence of 15-LOX in the sperm cytoplasmic droplet (CD). Testicular, epididymal and ejaculated spermatozoa were evaluated for the presence of 15-LOX using an affinity-purified immune serum raised against a synthetic peptide corresponding to the C-terminal sequence of rabbit reticulocyte 15-LOX. Western blotting revealed an appropriate single band of ~81 kDa in boar spermatozoa but not in boar seminal plasma. When ejaculated boar spermatozoa were subjected to separation on a 45/90% Percoll gradient, 15-LOX co-migrated with the immotile sperm and cellular debris/CD fractions, but not with the motile sperm fraction containing morphologically normal spermatozoa without CDs. Varied levels of 15-LOX were expressed in ejaculated sperm samples from boars with varied semen quality. By immunofluorescence, prominent 15-LOX immunoreactivity was found within the residual body in the testis and within the CDs from caput, corpus and cauda epididymal and ejaculated spermatozoa. Components of the ubiquitin-dependent proteolytic pathway, which is thought to facilitate both spermiogenesis and reticulocyte organelle degradation, were also detected in the sperm CD. These included ubiquitin, the ubiquitin-conjugating enzyme E2, the ubiquitin C-terminal hydrolase PGP 9.5, and various 20S proteasomal core subunits of the α- and β-type. The 15-LOX and various components of the ubiquitin–proteasome pathway were also detected in sperm CDs of other mammalian species, including the human, mouse, stallion and wild babirusa boar. We conclude that 15-LOX is prominently present in the mammalian sperm CD and thus may contribute to spermiogenesis, CD function or CD removal.

[Observation of apoptosis and proliferation in nasopharyngeal carcinoma]

In order to observe the apoptosis and proliferation of cells in nasopharyngeal carcinoma(NPC) and pericarcinomatous tissue(PCT), 49 cases of NPC and partly PCT were detected by in situ end-labelling (ISEL) technique and proliferating cell nuclear antigen(PCNA) immunohistochemical staining. The results showed that: 1. Massive distribution of ISEL positive cells was frequently exhibited in vesicular nucleus cell carcinoma(VNCC) of NPC, in which no apoptotic pattern character was found. 2. The positive rate and the staining intensity index(SII) of ISEL signals in NPC were higher than that in PCT(P < 0.05); the positive correlation between ISEL SII and PCNA SII was found in NPC(r = 0.341, P < 0.05), whereas the positive rate and the SII of ISEL signals were significantly lower than that of PCNA (P < 0.01). 3. The ISEL SII and the PCNA SII in VNCC were obviously higher than that in poorly differentiated squamous cell carcinoma(PDSCC) (P < 0.01, P < 0.05). Patients with VNCC had a high five-year survival rate. The results suggest that there is a relationship between cellular proliferation and cellular apoptosis in NPC.

[Apoptosis of CD4(+) T cells during experimental autoimmune neuritis in Wistar rats]

The present study describes apoptosis of T cells in the sciatic nerve in Wistar rats with experimental autoimmune neuritis(EAN). Morphological characterizations of apoptosis were found at the 18th day from onset, peaked at the 22nd day by immunocytochemical analysis. In situ end labeling(ISEL) techniques confirmed the presence of DNA fragmentation in CD4(+) T cells. It is suggested that apoptosis is an important clearance mechanism of infiltrated T cells in the peripheral nervous system(PNS) in EAN.

[Regulation of p53 and bcl-2 proteins to apoptosis and cell proliferation in liver cirrhosis and hepatocellular carcinoma]

In situ apoptosis labelling was used for detecting apoptotic cells, and immunohistochemistry for p53, bcl-2 proteins and proliferation cell nuclear antigen(PCNA) in hepatocellular carcinoma(HCC) and liver cirrhosis tissues. The results were that in HCC, the number of apoptotic cells was higher, the density of proliferation cells lower, and expressions of p53 and bcl-2 protein were stronger than that in liver cirrhosis, and they were related to differentiation degree of HCC. The data indicate that overexpression of bcl-2 and mutant p53 proteins, which causes imbalance between cell proliferation and apoptosis, may bring about genesis and development of HCC by selecting proliferation of cells.

[Changes on positive rate and distribution of Helicobacter pylori during progression of gastric cancer]

We observed changes on the positive rate and the distribution of helicobacter pylori (HP) in 7 case during early stage of gastric cancer and in 42 cases during middle-late stage of gastric cancer. The results showed that 1. the positive rate during early stage of gastric cancer was 57.1%, the positive rate during middle-rate stage of gastric cancer was 23.8%, 2. HP was not found within the gastric cancer lesions, 3. for HP positive cases, HP distribution during early stage of gastric cancer was more sparse than during middle-late stage of gastric cancer. These results suggested that HP can hardly live within the gastric cancer tissue, so the progression of gastric cancer is probably independent of HP. It may be a question that HP eradication can prevent later development of gastric cancer.

Microwave-induced thermoacoustic tomography: reconstruction by synthetic aperture

We have applied the synthetic-aperture method to linear-scanning microwave-induced thermoacoustic tomography in biological tissues. A nonfocused ultrasonic transducer was used to receive thermoacoustic signals, to which the delay-and-sum algorithm was applied for image reconstruction. We greatly improved the lateral resolution of images and acquired a clear view of the circular boundaries of buried cylindrical objects, which could not be obtained in conventional linear-scanning microwave-induced thermoacoustic tomography based on focused transducers. Two microwave sources, which had frequencies of 9 and 3 GHz, respectively, were used in the experiments for comparison. The 3 GHz system had a much larger imaging depth but a lower signal-noise ratio than the 9 GHz system in near-surface imaging.

[Effect of hepatitis C virus nonstructural protein NS3 on telomerase activity]

OBJECTIVE

To study the effect of hepatitis C virus nonstructural protein NS3 (HCV NS3) on telomerase activity and its carcinogenesis, and to observe the practical use of in situ telomerase activity labeling.

METHODS

NIH3T3 cells were transfected with plasmid pRcHCNS3-5prime prime or minute (expressing HCV NS3 C-terminal deleted protein), pRcHCNS3-3prime prime or minute (expressing HCV NS3 N-terminal deleted protein) and blank plasmid pRcCMV. Positive clones, 11 with plasmid pRcHCNS3-5prime prime or minute, 11 with pRcHCNS3-3prime prime or minute and 8 with plasmid pRcCMV were harvested respectively. Streptavidin-peroxidase conjugated method (SP) was used to detect the expression of HCV NS3 protein in NIH3T3 cells transfected with plasmid pRcHCNS3-5prime prime or minute and pRcHCNS3-3prime prime or minute. Telomerase activity was detected by in situ telomerase activity labeling method and telomerase PCR ELISA technique in the transfected and non-transfected NIH3T3 cells.

RESULTS

HCV NS3 protein was expressed in the cells transfected with plasmid pRcHCNS3-5prime prime or minute or plasmid pRcHCNS3-3prime prime or minute. The positive signals of HCV NS3 protein were localized in the cytoplasm of transfected NIH3T3 cells, and the signal intensity of the former was stronger (chi(2) = 6.667 P < 0.05). There was significant difference on telomerase activity between each group (F = 134.083 P < 0.01). Telomerase activity in all 11 clones with plasmid pRcHCNS3-5prime prime or minute was stronger than cells with plasmid pRcHCNS3-3prime prime or minute (P < 0.01), whereas telomerase activity in NIH3T3 cells transfected with the plasmid pRcCMV or non-transfected NIH3T3 cells were weaker than the cells with the plasmid pRcHCNS3-3prime prime or minute. The expression level of HCV NS3 protein were correlated significantly with the strength of telomerase activity (rs = 0.8084 P < 0.01). The results obtained with in situ telomerase activity labeling corresponded to those with telomerase PCR ELISA technique (rs = 0.50196 P < 0.01).

CONCLUSIONS

(1) HCV NS3 protein may activate telomerase through endogenous mechanism to induce host cells transformation. (2) The effect of HCV NS3 C-terminal deleted protein on telomerase activity in host cells may be more intense than that of HCV NS3 N-terminal deleted protein. (3) In situ telomerase activity labeling is a reliable technique for studying pathological morphology and telomerase activity in tissues and cells.

Giant room-temperature magnetoresistance in polycrystalline Zn(0.41)Fe(2.59)O4 with alpha-Fe2O3 grain boundaries

A tunneling-type magnetoresistance (MR) as large as 158% is observed at T = 300 K in a polycrystalline Zn0.41Fe2.59O4 sample, in which the Zn0.41Fe2.59O4 grains are separated by insulating alpha-Fe2O3 boundaries. The huge room-temperature MR is attributed to the high spin polarization of Zn(0.41)Fe(2.59)O4 grains and antiferromagnetic correlations between magnetic domains on both sides of the insulating alpha-Fe2O3 boundary. The MR exhibits strong temperature dependence below 100 K and its magnitude is enhanced to reach 1280% at 4.2 K, which may arise from the Coulomb blockade effect.