[Integrated Analysis of Soil Organic Matter Molecular Composition Changes Under Different Land Uses].

The application of biomarkers to study the molecular composition of soil organic matter (SOM) can be used to analyze the source and degradation of SOM and reveal the stability mechanism of soil organic carbon (SOC) at the molecular level. In order to further clarify the effects of different land use patterns (farmland, grassland, and forest) on the molecular composition of SOM, the changes in molecular composition of organic matter (free lipids, cutin, suberin, and lignin) on a global scale were studied using a meta-analysis method. The results showed that there were significant differences in the molecular composition of organic matter under different land use patterns. The contents of free lipids (n-alkanes, n-alkanols, n-alkanoic acids, and cyclic lipids), cutin, and lignin phenols in forest soil were significantly higher than those in grassland and farmland. There was no significant difference in the content of suberin between grassland and forest soil. The ratio of suberin to cutin in grassland was the highest, with an average of 2.96, and the averages of farmland and forest were 1.68 and 2.21, respectively. The ratio of syringic acid to syringaldehyde (Ad/Al)S and the ratio of vanillic acid to vanillin (Ad/Al)V of farmland soil were the largest, which were 1.25 and 1.58, respectively, and were significantly higher than those in grassland (0.46 and 0.69) and forest (0.78 and 0.7). The results of correlation analysis showed that in farmland soil, suberin was significantly correlated with mean annual precipitation (MAP) and clay; cutin was significantly correlated with clay; and lignin was significantly correlated with mean annual temperature (MAT), MAP, sand, and bulk density. In grassland soil, total free lipids were significantly correlated with MAP and bulk density; suberin and cutin were significantly correlated with MAT and MAP; and lignin was significantly correlated with MAP, pH, sand, and bulk density. However, only lignin was significantly correlated with MAP and sand in forest soils. Overall, the contents of SOC and molecular components in forest soil were higher under the three land use practices, and the contribution of plant roots to SOM in grassland soil was greater. In farmland soil, the degradation of lignin was accelerated due to human farming activities. Future research should focus on the regulation of soil physicochemical properties and climatic conditions on the molecular composition of SOM.

Immunogenicity and protective efficacy of a multi-epitope recombinant toxin antigen of Pasteurella multocida against virulent challenge in mice.

Pasteurella multocida (P. multocida) infection frequently results in porcine atrophic rhinitis and swine plague, leading to large economic losses for the swine industry worldwide. P. multocida toxin (PMT, 146 kDa) is a highly virulent key virulence factor that plays a vital role in causing lung and turbinate lesions. This study developed a multi-epitope recombinant antigen of PMT (rPMT) that showed excellent immunogenicity and protection in a mouse model. Using bioinformatics to analyse the dominant epitopes of PMT, we constructed and synthesized rPMT containing 10 B-cell epitopes, 8 peptides with multiple B-cell epitopes and 13 T-cell epitopes of PMT and a rpmt gene (1,974 bp) with multiple epitopes. The rPMT protein (97 kDa) was soluble and contained a GST tag protein. Immunization of mice with rPMT stimulated significantly elevated serum IgG titres and splenocyte proliferation, and serum IFN-γ and IL-12 were upregulated by 5-fold and 1.6-fold, respectively, but IL-4 was not. Furthermore, the rPMT immunization group exhibited alleviated lung tissue lesions and a significantly decreased degree of neutrophil infiltration compared with the control groups post-challenge. In the rPMT vaccination group, 57.1% (8/14) of the mice survived the challenge, similar to the bacterin HN06 group, while all the mice in the control groups succumbed to the challenge. Thus, rPMT could be a suitable candidate antigen for developing a subunit vaccine against toxigenic P. multocida infection.

Expression of IARS2 gene in colon cancer and effect of its knockdown on biological behavior of RKO cells.

OBJECTIVE: To investigate the expression level of IARS2 gene in colon cancer tissues and various cell strains of the cancer; to explore cytologically the effect of IARS2 gene knockdown on proliferation, apoptosis and cell cycle of RKO cells in the cancer. METHODS: Real-time, fluorescence-based quantitative PCR (qPCR) was used to detect the expression of IARS2 gene in human colon cancer and surrounding tissues and in various cell strains of the cancer; the RNA interference target of IARS2 gene was designed and the target was detected by Western blot; the IARS2-siRNA lentiviral vector was established and used to infect the RKO cells of colon cancer; qPCR was employed to determine the effect of gene knockdown; changes of the RKO cells in growth, apoptosis, cell cycle and clone formation were observed after IARS2 gene knockdown. RESULTS: The expression of IARS2 gene was higher in human colon cancer tissues than in surrounding tissues; there was expression of IARS2 gene in colon cancer cells, and the expression level of IARS2 gene mRNA was higher in the RKO cells than in the SW480, HCT116, DLD1, HT-29 and SW620 cells. After infection of the RKO cells with IARS2-siRNA lentivirus, the expression of IARS2 gene was inhibited in the level of mRNA; proliferation rate of the RKO cells was significantly inhibited; the G1 phase arrest of the RKO cells was increased with less RKO cells in S phase; the apoptotic RKO cells increased significantly; and the number of colonies of the RKO cells reduced. CONCLUSION: The expression of IARS2 gene is different in human colon cancer and surrounding tissues; after knockdown of IARS2 gene, proliferation of the RKO cells is inhibited; there are more cells in G phase and fewer cells in S phase; apoptosis of cells is increased; and formation of colonies is reduced. IARS2 gene is probably a cancer-promoting gene.

Protective effects of L-carnitine on intestinal ischemia/reperfusion injury in a rat model.

BACKGROUND: Ischemia/reperfusion (IR) injury of the intestine is a major problem in abdominal pathological condition and is associated with a high morbidity and mortality. The purpose of the study is to determine whether the L-carnitine can prevent the harmful effects of small intestinal IR injury in rats. METHODS: Thirty Sprague-Dawley rats were randomly divided into three groups. Sham operated group (S), for shamoperated, the IR group for rats submitted to 45-minute of intestinal ischemia and 2-hour reperfusion, and IR+L group for those IR group treated with L-carnitine before reperfusion. All the rats were given EmGFP labelled E. coli DH5α through gavage 2-hour before the operative procedure. Afterwards the bacterial translocation (BT) from mesenteric lymph nodes (MLN), liver, spleen, lung and portal vein blood were detected. And the colony forming units/g (CFU/g) were counted. The TNF-α, IL-1ß, IL-6, and IL-10 in serum were measured by ELISA. The morphometric study was measured by Chius classification. RESULTS: The levels of BT were higher in the IR group than IR+L group (P < 0.05). The E. coli DH5α was hardly detected in the S group. The IR+L rats had enhancement of IL-10 and suppressed production of serum TNF-α, IL-1ß and IL-6, compared to IR group rats (P < 0.05). The degree of pathological impairment in small intestine was lighter in IR+L than IR group (P < 0.05). CONCLUSIONS: The L-carnitine pretreatment has a positive effect on reducing levels of BT, on inhibiting secretion of proinflammatory cytokines, and on lessening intestinal mucosa injury during small intestinal IR injury. KEYWORDS: L-carnitine; Ischemia/reperfusion injury; Intestine.

Relief of abdominal pain by morphine without altering physical signs in acute appendicitis.

BACKGROUND: Abdominal pain is a common symptom among patients with acute appendicitis, yet these patients have long been denied relief from suffering because of widespread misconceptions associated with the use of opioids. We determined whether morphine hydrochloride masked the physical signs in adults with acute appendicitis and assessed the efficacy of morphine in relieving abdominal pain. METHODS: A prospective, double-blind, placebo controlled, clinical trial was conducted with 106 adult patients between 16 and 70 years old with acute appendicitis. Patients were randomly divided into a morphine group (n=54) or a normal saline group (n=52). All patients presented with acute abdominal pain with onset within 3 days. The morphine group received hypodermic injection of morphine (0.15 mg/kg; maximum 20 mg) and the control group members were given an equivalent volume of normal saline solution. The clinical symptoms, physical signs, and patients' cooperation during physical examination were assessed before and after 30 minutes of morphine or normal saline administration. RESULTS: Abdominal pain was significantly relieved and the patients' cooperation was improved in the morphine group after 30 minutes treatment compared with the control group and before morphine administration (P<0.05). The physical signs were unaffected by either treatment (P>0.05). CONCLUSIONS: Morphine relieved abdominal pain and improved the patients' cooperation for treatment and care. Furthermore, the morphine did not mask the physical signs of acute appendicitis.

Effects of recombinant human growth hormone on growth of human gastric carcinoma xenograft model in nude mice.

AIM: To study effects of recombinant human growth hormone (rhGH) on growth of a human gastric carcinoma cell in vivo. METHODS: Experimental mice were divided into control group, rhGH group, oxaliplatin (L-OHP) group and rhGH+L-OHP group. Cultured human gastric carcinoma cells BGC823 were inoculated into right axilla of nude mice and carcinoma xenograft model was established successfully. Inhibitory rate of xenograft tumor growth was estimated by measuring tumor volume; expression of proliferating cell nuclear antigen (PCNA), Bax and Bcl-2 proteins of xenograft tumor was detected using immunohistochemical S-P method. RESULTS: Tumor growth inhibitory rate, the positive expression rate of PCNA, Bax and Bcl-2 were 49.3%, 58.2%, 65.2% and 59.2% in rhGH+L-OHP group respectively; 46.6%, 62.5%, 59.7% and 64.7% in L-OHP group; 5.0%, 82.7%, 23.2% and 82.2% in rhGH group and 0, 77.8%, 23.5% and 80.3% in control group. There was significant difference between rhGH+L-OHP group (or L-OHP group ) and control group or rhGH group (P < 0.05), whereas there were no significant differences (P > 0.05) between L-OHP group and rhGH+L-OHP group and between rhGH group and control group. CONCLUSION: rhGH does not accelerate the proli-feration of human gastric cancer cell in vivo.

In vitro effects of recombinant human growth hormone on growth of human gastric cancer cell line BGC823 cells.

AIM: To study the effects of recombinant human growth hormone (rhGH) on growth of human gastric cancer cell line in vitro. METHODS: Experiment was divided into control group, rhGH group, oxaliplatin (L-OHP) group and rhGH+L-OHP group. Cell inhibitory rate, cell cycle, cell proliferation index (PI) and DNA inhibitory rate of human gastric cancer line BGC823, at different concentrations of rhGH treatment were studied by cell culture, MTT assay and flow cytometry. RESULTS: The distinctly accelerated effects of rhGH on multiplication of BGC823 cell line were not found in vitro. There was no statistical significance between rhGH group and control group, or between rhGH+L-OHP group and L-OHP group (P>0.05). The cell growth curve did not rise. Cell inhibitory rate and cells arrested in G(0)-G(1) phase were obviously increased. Meanwhile, cells in S phase and PI were distinctly decreased and DNA inhibitory rate was obviously increased in rhGH+L-OHP group in comparison with control group and rhGH group, respectively (P<0.01). Cell inhibitory rate showed an increasing trend and PI showed a decreasing trend in rhGH+L-OHP group compared with L-OHP group. CONCLUSION: In vitro rhGH does not accelerate the multiplication of human gastric cancer cells. It may increase the therapeutic efficacy when it is used in combination with anticancer drugs.

Immobilization of Pseudomonas delafieldii with magnetic polyvinyl alcohol beads and its application in biodesulfurization.

Pseudomonas delafieldii was immobilized in magnetic polyvinyl alcohol (PVA) beads using a hydrophilic magnetic fluid, which was prepared by a co-precipitation method. The beads had distinct super-paramagnetic properties and were compared with immobilized cells in non-magnetic PVA beads. Their desulfurizing activity was increased slightly from 8.7 to 9 mmol sulfur kg(-1) (dry cell) h(-1). The main advantages was that the magnetic immobilized cells maintain a high desulfurization activity and remain in good shape after 7 times of repeated use, while the non-magnetic immobilized cells could only be used for 5 times. Furthermore, the magnetic immobilized cells could be easily collected or separated magnetically from the biodesulfurization reactor.