Performance enhancement of gas sensing by modification of molybdenum selenide nanosheets with metal nanoparticles.

In this paper, nanostructured molybdenum selenide (MoSe2) with composited phases are synthesized by hydrothermal method, and the products are modified by metal anoparticles to improve the gas sensing performance. Microstructure characterization shows that few layered 1T/2H-MoSe2nanosheets have been successfully prepared. Both the morphology and component of nanosheets could be tuned by the reaction parameters. It is shown the MoSe2-based nanomaterials have excellent selectivity to nitrogen dioxide (NO2) according to gas sensing properties measurement. The sensitivity of 1T/2H-MoSe2nanosheets modified by Cu nanoparticles is 17.73 (50 ppm NO2) at the optimal operating temperature, which is the highest compared with other samples. The sensors also exhibit rapid response/recovery time and high stability. The sensing mechanism of MoSe2nanosheets toward NO2is investigated based on the first-principles calculation. The results suggest the modification by metal nanoparticles could significantly improve the adsorption energy and charge transfer between gas molecule and MoSe2. This work demonstrates a promising guidance for the design of new NO2gas sensing materials and devices.

Performance Enhancement of Gas Sensing by Modification of Molybdenum Selenide Nanosheets with Metal Nanoparticles.

In this paper, nanostructured Molybdenum Selenide (MoSe2) with composited phases are synthesized by hydrothermal method, and the products are modified by metal anoparticles to improve the gas sensing performance. Microstructure characterization shows that few layered 1T/2H-MoSe2 nanosheets have been successfully prepared. Both the morphology and composition of nanosheets could be tuned by the reaction parameters. It is shown the MoSe2-based nanomaterials have excellent selectivity to Nitrogen dioxide (NO2) according to gas sensing properties measurement. The sensitivity of 1T/2H-MoSe2 nanosheets modified by Cu nanoparticles is 17.73 (50 ppm NO2) at the optimal operating temperature, which is the highest compared with other samples. The sensors also exhibit rapid response/recovery time and high stability. The sensing mechanism of MoSe2 nanosheets toward NO2 is investigated based on the first-principles calculation. The results suggest the modification by metal nanoparticles could significantly improve the adsorption energy and the charge transfer between gas molecule and MoSe2. This work demonstrates a promising guidance for the design of new NO2 gas sensing materials and devices.

Metastasis tumor antigen 1 is involved in the resistance to heat stress-induced testicular apoptosis.

Our previous study documented the expression of Mta1 during spermatogenesis. Here, we present evidence for a possible involvement of Mta1 in the regulation of testicular function, possibly by interacting with p53. A notable decrease of Mta1 expression was revealed at postsurgical day 6, consistent with the previously reported upregulation of p53 in mouse cryptorchidism. Furthermore, in vitro over-expression of Mta1 could remarkably elevate the resistance capability of spermatogenic tumor cells against heat-induced apoptosis with a marked impairment of p53 expression. These findings indicate that Mta1 may operate as a negative modifier of apoptosis by interacting with p53 during gametogenesis.

Involvement of metastasis tumor antigen 1 in hepatic regeneration and proliferation.

BACKGROUND/AIMS: Metastasis tumor antigen 1 (MTA1), an integral part of nucleosome remodeling and histone deacetylation (NuRD) complexes, is well correlated with the potential of metastasis, with the ability to regulate divergent cellular pathways by modifying the acetylation status of crucial target genes. However, additional biological functions of this molecule remain largely unexplored. This study was undertaken to explore the potential role of this molecule in mouse liver. METHODS: MTA1 expression was firstly explored in mouse partial hepatectomy model (PHx). The effect of overexpression of MTA1 on hepatic proliferation and differentiation was then examined in vivo by hydrodynamic-based gene transfer method and in vitro using transformed cell line AML12 overexpressing MTA1, respectively. RESULTS: Consistent with the hepatic regeneration, MTA1 expression was significantly increased 24h post-PHx, with a maximum level at 48h after PHx. MTA1 immunoreactivity was generally elevated right after PHx and the staining appeared to experience a cytoplasm-to-nuclear transition. Overexpression of exogenous MTA1 could notably stimulate hepatic proliferation in vivo and could also accelerate hepatocyte differentiation in vitro. CONCLUSION: These data underscore a hepatocelluar facet of this recently defined molecule, which may represent as a novel regulator and a new therapeutic target for the treatment of impaired liver.

Expression of thyrotropin-releasing hormone receptors in rat testis and their role in isolated Leydig cells.

Thyrotropin-releasing hormone (TRH) was initially discovered as a neuropeptide synthesized in the hypothalamus. Receptors for this hormone include TRH-receptor-1 (TRH-R1) and -2 (TRH-R2). Previous studies have shown that TRH-R1 and TRH-R2 are localized exclusively in adult Leydig cells (ALCs). We have investigated TRH-R1 and TRH-R2 expression in the testes of postnatal 8-, 14-, 21- 35-, 60-, and 90-day-old rats and in ethane dimethane sulfonate (EDS)-treated adult rats by using Western blotting, immunohistochemistry, and immunofluorescence. The effects of TRH on testosterone secretion of primary cultured ALCs from 90-day-old rats and DNA synthesis in Leydig cells from 21-day-old rats have also been examined. Western blotting and immunohistochemistry demonstrated that TRH-R1 and TRH-R2 were expressed in fetal Leydig cells (in 8-day-old rats) and in all stages of adult-type Leydig cells during development. Immunofluorescence double-staining revealed that newly regenerated Leydig cells in post-EDS 21-day rats expressed TRH-R1 and TRH-R2 on their first reappearance. Incubation with various doses of TRH affected testosterone secretion of primary cultured ALCs. Low concentrations of TRH (0.001, 0.01, and 0.1 ng/ml) inhibited basal and human chorionic gonadotrophin (hCG)-stimulated testosterone secretion of isolated ALCs, whereas relatively high doses of TRH (1 and 10 ng/ml) increased hCG-stimulated testosterone secretion. As detected by a 5-bromo-2'-deoxyuridine incorporation test, the DNA synthesis of Leydig cells from 21-day-old rats was promoted by low TRH concentrations. Thus, we have clarified the effect of TRH on testicular function: TRH might regulate the development of Leydig cells before maturation and the secretion of testosterone after maturation.

Immunolocalization assessment of metastasis-associated protein 1 in human and mouse mature testes and its association with spermatogenesis.

AIM: To investigate the stage-specific localization of metastasis-associated protein 1 (MTA1) during spermatogenesis in adult human and mouse testis. METHODS: The immunolocalization of MTA1 was studied by immunohistochemistry and Western blot analysis. The distribution pattern of MTA1 in mouse testis was confirmed by using quantitative analysis of purified spermatogenic cells. RESULTS: The specificity of polyclonal antibody was confirmed by Western blot analysis. MTA1 was found expressed in the nucleus of germ cells, except elongate spermatids, and in the cytoplasm of Sertoli cells; Leydig cells did not show any specific reactivity. MTA1 possessed different distribution patterns in the two species: in humans, the most intensive staining was found in the nucleus of round spermatids and of primary spermatocytes while in mice, the most intense MTA1 staining was in the nucleus of leptotene, zygotene and pachytene spermatocytes. In both species the staining exhibited a cyclic pattern. CONCLUSION: The present communication initially provides new evidence for the potential role of MTA1 in mature testis. In addition, its distinctive expression in germ cells suggests a regulatory role of the peptide during spermatogenesis.

DHA depletion in rat brain is associated with impairment on spatial learning and memory.

OBJECTIVE: To examine the effect of docosahexaenoic acid (DHA) deficiency in brain on spatial learning and memory in rats. METHODS: Sprague Dawley rats were fed with an n-3 fatty acid deficient diet for two generations to induce DHA depletion in brain. DHA in seven brain regions was analyzed using the gas-liquid chromatography. Morris water maze (MWM) was employed as an assessing index of spatial learning and memory in the n-3 fatty acid deficient adult rats of second generation. RESULTS: Feeding an n-3 deficient diet for two generations depleted DHA differently by 39%-63% in the seven brain regions including cerebellum, medulla, hypothalamus, striatum, hippocampus, cortex and midbrain. The MWM test showed that the n-3 deficient rats took a longer time and swam a longer distance to find the escape platform than the n-3 Adq group. CONCLUSION: The spatial learning and memory in adult rats are partially impaired by brain DHA depletion.

Expression and localization of Smad1, Smad2 and Smad4 proteins in rat testis during postnatal development.

AIM: To study the expression and regulation of Smad1, Smad2 and Smad4 proteins (intracellular signaling molecules of transforming growth factor-b family) in rat testis during postnatal development. METHODS: The whole testes were collected from SD rats aged 3, 7, 14, 28 and 90 (adult) days. The cellular localization and developmental changes were examined by immunohistochemistry ABC method with the glucose oxidase-DAB-nickel enhancement technique. Quantitative analysis of the immunostaining was made by the image analysis system. The Smads proteins coexistence in the adult rat testis was tested by the double immune staining for CD14-Smad4 and Smad2-Smad4. The protein expression of Smad during rat testicular development was examined by means of Western blots. RESULTS: Smad1, Smad2 and Smad4 were present throughout testicular development. The immunostaining of Smad1 and Smad2 were present in spermatogenic cells. A positive immunoreactivity was located at the cytoplasm, but the nucleus was negative. Smad1 was immunolocalized at the d14, d28 and adult testes, while Smad2, at the d7, d14, d28 and adult testis. There was positive immunoreaction in the Sertoli cells and Leydig cells as well. The immunolocalization of Smad4 was exclusively at the cytoplasm of Leydig cells and the nuclei were negative throughout the testicular development. No expression was detected in the germ cells. The results of image and statistical analysis showed that generally the expression of Smad1, Smad2 and Smad4 in the testis tended to increase gradually with the growth of the rat. CONCLUSION: The present data provide direct evidences for the molecular mechanism of TGF-bgr action in rat testes during postnatal development and spermatogenesis.

Stage-specific localization of transforming growth factor beta1 and beta3 and their receptors during spermatogenesis in men.

AIM: To investigate the stage-specific localization of transforming growth factor (TGF) beta1 and beta3 during spermatogenesis in adult human testis. METHODS: The localization of TGFbeta1 and beta3 was investigated by immunohistochemical staining method employing specific polyclonal antibodies. RESULTS: Both TGFbeta1 and beta3 and their receptors were preponderant in the Leydig cells. TGFbeta1 could not be detected in the seminiferous tubules. TGFbeta3 and TGFbeta-Receptor (R) I were mainly seen in the elongated spermatids, while TGFbeta-RII in the pachytene spermatocytes and weak in the spermatogonia, spermatids and Sertoli cells. Only TGFbeta-RII was detected in the Sertoli cells. TGFbeta3, TGFbeta-RI and TGFbeta-RII showed a staining pattern dependent upon the stages of the seminiferous epithelium cycle. CONCLUSION: TGFbeta isoforms and their receptors are present in the somatic and germ cells of the adult human testis, suggesting their involvement in the regulation of spermatogenesis.

Correlation of expression of preprothyrotropin-releasing hormone and receptor with rat testis development.

OBJECTIVE: To investigate the expression regulation of thyrotrophin-releasing hormone (TRH) and TRH receptor (TRH-R), and their role in the development of rat testis. METHODS: Oligonucleotide primers were designed from the sequences of rat hypothalamus prepro TRH (ppTRH) and pituitary TRH-R cDNA for reverse transcription polymerase chain reaction (RT-PCR). Specific fragments of ppTRH and TRH-R cDNA were cloned and sequenced. Expression plasmids containing ppTRH and TRH-R genes were then constructed, and expression was found in E. coli DH5-alpha. ppTRH and TRH-R mRNA in the testis was quantitated in RNA samples prepared from rats at different developmental stages by real time quantitative RT-PCR. RESULTS: The quantitative analyses demonstrated that no ppTRH and TRH mRNA could be detected at the earliest stage (day 8). ppTRH and TRH mRNA signals were detected on day 15 and increased progressively on days 20, 35, 60 and 90. CONCLUSION: Our results suggest that rat testis could specifically express TRH and TRH-R, and the transcriptions of ppTRH and TRH-R genes in the rat testis were development-dependent. The acquirement of expressed products for ppTRH and TRH-R can be used for further research on the physiological significance of TRH and TRH-R expression in rat testis.

Dietary supplementation of soy germ phytoestrogens or estradiol improves spatial memory performance and increases gene expression of BDNF, TrkB receptor and synaptic factors in ovariectomized rats.

BACKGROUND: Estrogen or phytoestrogens treatment has been suggested to improve cognitive function of the brain in postmenopausal women. However, there is lack of information on the mechanism of such treatment on the central nervous system. The present study aimed to determine the effects of estradiol and soy germ phytoestrogens on spatial memory performance in ovariectomized rats and to explore the underlying mechanisms affecting the central nervous system. METHODS: Ovariectomized Sprague-Dawley rats were fed a basic diet supplemented with soy germ phytoestrogens (0.4 g/kg or 1.6 g/kg) or 17ß-estradiol (0.15 g/kg) for 12 weeks. At the end of the experiment, animals were evaluated for their spatial learning and memory performance by the Morris Water Maze task. The expressions of brain-derived neurotrophic factor (BDNF) and synaptic formation proteins in the hippocampal tissue were estimated using RT-PCR and ELISA. RESULTS: It was found that rats supplemented with soy germ phytoestrogens or estradiol performed significantly better in spatial memory acquisition and retention when compared to the rats fed on the control diet. Estradiol or the high dose of phytoestrogens treatment significantly increased BDNF concentration and the mRNA levels for BDNF and its TrkB receptors as well as the synaptic formation proteins, synaptophysin, spinophilin, synapsin 1 and PSD-95, in the hippocampal tissue of the experimental animals. It was also found that phytoestrogens, in contrast to estradiol, did not show any significant effect on the vaginal and uteri. CONCLUSION: Soy germ phytoestrogens, which may be a substitute of estradiol, improved spatial memory performance in ovariectomized rats without significant side-effects on the vaginal and uteri. The memory enhancement effect may relate to the increase in BDNF and the synaptic formation proteins expression in the hippocampus of the brain.

Lycium barbarum polysaccharides induce apoptosis in human prostate cancer cells and inhibits prostate cancer growth in a xenograft mouse model of human prostate cancer.

Lycium barbarum polysaccharides (LBPs) are important functional constituents in red-colored fruits of L. barbarum (Guo Qi Zi, a well-known traditional Chinese medicinal plant commonly known as Goji berry or wolfberry). The influence of LBP on human prostate cancer cells was systematically investigated in vitro and in vivo. The in vitro effects of LBP on two cell lines (PC-3 and DU-145) were examined by using trypan blue exclusion staining, single-cell gel electrophoresis, flow cytometry, terminal dUTP nick-end labeling assay, and immunohistochemical assay (assessment of Bcl-2 and Bax expression). The in vivo effect of LBP on PC-3 cells was assessed in the nude mouse xenograft tumor model. The in vitro results showed that LBP can dose- and time-dependently inhibit the growth of both PC-3 and DU-145 cells. LBP caused the breakage of DNA strands of PC-3 and DU-145 cells; the tail frequency and tail length were significantly higher than that of control cells. LBP also markedly induced PC-3 and DU-145 cell apoptosis, with the highest apoptosis rates at 41.5% and 35.5%, respectively. The ratio of Bcl-2/Bax protein expression following LBP treatments decreased significantly with a dose-effect relationship, which suggested that LBP can regulate the expression of Bcl-2 and Bax to induce apoptosis of PC-3 and DU-145 cells. The in vivo experimental results indicate that LBP might significantly inhibit PC-3 tumor growth in nude mice. Both the tumor volume and weight of the LBP treatment group were significantly lower than those of the control group.

Temporal proteomic analysis of intestine developing necrotizing enterocolitis following enteral formula feeding to preterm pigs.

Necrotizing enterocolitis (NEC), a serious gastrointestinal inflammatory disease, frequently occurs in preterm neonates that fail to adapt to enteral nutrition. A temporal gel-based proteomics study was performed on porcine intestine with NEC lesions induced by enteral formula feeding. Functional assignment of the differentially expressed proteins revealed that important cellular functions, such as the heat shock response, protein processing; and purine, nitrogen, energy metabolism, were possible involved in the early progression of NEC.

The effects of perinatal protein malnutrition on spatial learning and memory behaviour and brain-derived neurotrophic factor concentration in the brain tissue in young rats.

This study aimed to investigate the effects of perinatal protein malnutrition on brain derived-neurotrophic factor (BDNF) concentration in brain tissue and spatial learning and memory performance in young rats. Nine pregnant Wistar rats were assigned into three groups. Rats in one group were fed with a control diet containing 20% protein. Rats in remaining two groups were fed with a diet containing 6% protein from gestation day eight and day 15 respectively till four weeks after birth. At four weeks of age, the rat pups were evaluated for spatial learning ability using Morris Water Maze (MWM) task. At the end of the behaviour tests, rat pups were sacrificed and the brain tissue samples were collected for measurement of total protein and BDNF concentrations. It was found that rat pups fed the low protein diet had lower body weight and slightly lighter brain compared to the control pups. Total protein levels in hippocampus and cerebral cortex were significantly lower in malnourished pups than the controls. The concentration of BDNF in the hippocampus was also significantly lower in rat pups suffered protein malnutrition from early pregnancy than in the controls. MWM tests showed that perinatal protein deprivation, particularly from early pregnancy, significantly impaired learning and memory ability. The results of the present study indicate that perinatal protein malnutrition had adverse influence on spatial navigation and brain BDNF levels in rats. The decreased hippocampal BDNF concentration might partially contribute to the poor learning memory performance in the protein deprived rats.

Correlation of appearance of metastasis-associated protein1 (Mta1) with spermatogenesis in developing mouse testis.

Mta1, a representative of the MTA gene family, is believed to be involved in the metastasis of malignant tumors. However, a systematic study of its physiological function has not been performed. It has been found in normal mouse organs at relatively low levels, except for in testis, suggesting a potential function in the male reproductive system. In order to explore the role of Mta1 protein during spermatogenesis, its expression in adult mouse testis was compared with that in developing mouse testis and in testis from adult mice treated with methoxyacetic acid, which selectively depletes primary spermatocytes. Quantitative analysis revealed that Mta1 protein gradually increased in the testis from 14 days postnatally. Immunolocalization analysis demonstrated strong signals in the seminiferous tubules, and Mta1 was predominantly present in the nucleus of primary spermatocytes and spermatogonia from 14 days postnatally. The most intensive staining was located in the nucleus of pachytene spermatocytes in mature testes. The expression pattern of Mta1 during spermatogenesis was also shown to be stage-specific by immunohistochemistry analysis. Finally, dramatic loss of Mta1 expression from pachytene spermatocytes was observed in the spermatogenic-arrested adult mouse testis. These results collectively demonstrate that Mta1 appears during postnatal testis development and suggest that this expression may be crucial for spermatogenesis.

Serial changes in urinary proteome profile of membranous nephropathy: implications for pathophysiology and biomarker discovery.

Membranous nephropathy is one of the most common causes of primary glomerular diseases worldwide. The present study adopted a gel-based proteomics approach to better understand the pathophysiology and define biomarker candidates of human membranous nephropathy using an animal model of passive Heymann nephritis (PHN). Clinical characteristics of Sprague-Dawley rats injected with rabbit anti-Fx1A antiserum mimicked those of human membranous nephropathy. Serial urine samples were collected at Days 0, 10, 20, 30, 40, and 50 after the injection with anti-Fx1A (number of rats = 6; total number of gels = 36). Urinary proteome profiles were examined using 2D-PAGE and SYPRO Ruby staining. Quantitative intensity analysis and ANOVA with Tukey post-hoc multiple comparisons revealed 37 differentially expressed proteins among 6 different time-points. These altered proteins were successfully identified by MALDI-TOF MS and classified into 6 categories: (i) proteins with decreased urinary excretion during PHN; (ii) proteins with increased urinary excretion during PHN; (iii) proteins with increased urinary excretion during PHN, but which finally returned to basal levels; (iv) proteins with increased urinary excretion during PHN, but which finally declined below basal levels; (v) proteins with undetectable levels in the urine during PHN; and (vi) proteins that were detectable in the urine only during PHN. Most of these altered proteins have functional significance in signaling pathways, glomerular trafficking, and controlling the glomerular permeability. The ones in categories (v) and (vi) may serve as biomarkers for detecting or monitoring membranous nephropathy. After normalization of the data with 24-h urine creatinine excretion, changes in 34 of initially 37 differentially expressed proteins remained statistically significant. These data underscore the significant impact of urinary proteomics in unraveling disease pathophysiology and biomarker discovery.

Transient changes of transforming growth factor-beta expression in the small intestine of the pig in association with weaning.

It is well known that early weaning causes marked changes in intestinal structure and function, and transforming growth factor-beta (TGF-beta) is believed to play an important regulatory role in post-weaning adaptation of the small intestine. The present study examined the distribution and expression intensity of TGF-beta in the small intestinal mucosa of pre- and post-weaning pigs using a specific immunostaining technique and Western blot analysis. The level of TGF-beta in the intestinal mucosa, as estimated by Western blot analysis, did not change significantly during weaning. However, when examined by the immunostaining technique, TGF-beta1 (one of the TGF-beta isoforms dominantly expressed in the tissue) at the intestinal villus epithelium, particularly at the apical membrane of the epithelium, decreased significantly 4 d after weaning, while the staining intensity increased significantly at the intestinal crypts compared with that in pre-weaning pigs. These changes were transient, with the immunostaining intensity for TGF-beta1 at the intestinal villi and the crypts returning to the pre-weaning level by 8 d post-weaning. The transient decrease in TGF-beta1 level at the intestinal villus epithelium was associated with obvious intestinal villus atrophy and marked reduction of mucosal digestive enzyme activities. Furthermore, the number of leucocytes staining positively for TGF-beta1 increased significantly in the pig intestinal lamina propria 4 d after weaning. These findings strongly suggest that TGF-beta plays an important role in the post-weaning adaptation process in the intestine of the pig.