RNA m5C regulator-mediated modification patterns and the cross-talk between tumor microenvironment infiltration in gastric cancer.

The effect of immunotherapy strategy has been affirmed in the treatment of various tumors. Nevertheless, the latent role of RNA 5-methylcytosine (m5C) modification in gastric cancer (GC) tumor microenvironment (TME) cell infiltration is still unclear. We systematically explore the m5C modification patterns of 2,122 GC patients from GEO and TCGA databases by 16 m5C regulators and related these patterns to TME characteristics. LASSO Cox regression was employed to construct the m5Cscore based on the expression of regulators and DEGs, which was used to evaluate the prognosis. All the GC patients were divided into three m5C modification clusters with distinct gene expression characteristics and TME patterns. GSVA, ssGSEA, and TME cell infiltration analysis showed that m5C clusters A, B, and C were classified as immune-desert, immune-inflamed, and immune-excluded phenotype, respectively. The m5Cscore system based on the expression of eight genes could effectively predict the prognosis of individual GC patients, with AUC 0.766. Patients with a lower m5Cscore were characterized by the activation of immunity and experienced significantly longer PFS and OS. Our study demonstrated the non-negligible role of m5C modification in the development of TME complexity and inhomogeneity. Assessing the m5C modification pattern for individual GC patients will help recognize the infiltration characterization and guide more effective immunotherapy treatment.

THZ1 targeting CDK7 suppresses c-KIT transcriptional activity in gastrointestinal stromal tumours.

BACKGROUND: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract and are characterized by activating mutations of c-KIT or PDGFRa receptor tyrosine kinases (RTKs). Despite the clinical success of tyrosine kinase inhibitors (TKIs), more than half of GIST patients develop resistance due to a second mutation. Cyclin-dependent kinase 7 (CDK7) is the catalytic subunit of CDK-activating kinase (CAK), and it plays an important role in the regulation of cell cycle transitions and gene transcription. THZ1, a CDK7 inhibitor, exhibits a dose-dependent inhibitory effect in various cancers. METHODS: Data from the public GEO database and tissue microarray were used to analyse the gene expression levels of CDKs in GISTs. The impact of CDK7 knockdown and the CDK7 inhibitor THZ1 on GIST progression was investigated in vitro using CCK-8, colony formation, and flow cytometry assays and in vivo using a xenograft mouse model. RNA sequencing was performed to investigate the mechanism of GIST cell viability impairment mediated by THZ1 treatment. RESULTS: Our study demonstrated that CDK7 is relatively overexpressed in high-risk GISTs and predicts a poor outcome. A low concentration of THZ1 exhibited a pronounced antineoplastic effect in GIST cells in vivo and in vitro. Moreover, THZ1 exerted synergistic anticancer effects with imatinib. THZ1 treatment resulted in transcriptional modulation by inhibiting the phosphorylation of Ser2, Ser5, and Ser7 within RNA polymerase II (RNAPII). c-KIT, an oncogene driver of GIST, was transcriptionally repressed by THZ1 treatment or CDK7 knockdown. Transcriptome sequencing analysis showed that OSR1 acts as a downstream target of CDK7 and regulates c-KIT expression. Taken together, our results highlight elevated CDK7 expression as a predictor of poor outcome in GIST and present the combination of CDK7 and RTK inhibitors as a potent therapeutic strategy to improve the efficacy of GIST treatment. Video abstract.

Efficacy of intravenous immunoglobulin in the treatment of recurrent spontaneous abortion: A systematic review and meta-analysis.

OBJECTIVE: We aimed to evaluate the efficacy of IVIG in the treatment with patients with recurrent spontaneous abortion (RSA). METHODS: PubMed, Embase, Web of science, Cochrane library were searched for randomized controlled (RCTs) about effect of IVIG on RSA from inception to August 20, 2021. Values of standardized mean differences (SMD) were determined for continuous outcomes. RESULTS: A total of 15 articles involving 902 patients were included in meta-analysis. Compared with the control group, IVIG can increase the live birth rate of recurrent spontaneous abortion patients [OR = 3.06, 95%CI (1.23, 7.64, P = .02]. However, recurrent abortion was divided into primary and secondary abortion for subgroup analysis, and there was no statistical difference. Besides, IVIG can also increase the expression in peripheral blood CD3+[OR = .4, 95%CI(-2.47, 3.15, P = .81],CD4+[OR = 1.16, 95%CI(-4.60, 6.93, P = .69], and a decrease in the expression of CD8+[OR = -1.78, 95%CI(-5.30, 1.75, P = .32], but there is no statistical significance. CONCLUSIONS: IVIG can significantly increase the live birth rate of recurrent spontaneous abortion. However, the evidence needs further verification and the curative effect is uncertain. It is necessary to further explore the pathogenesis of recurrent abortion and the mechanism of IVIG in the treatment of recurrent spontaneous abortion. Besides, more high-quality randomized controlled trials suitable for population, race, dosage and timing of IVIG in the treatment of recurrent abortion are needed to confirm its effectiveness, and effective systematic evaluation is also needed to evaluate its use benefit.

Role of Surgery in the Management of Liver Metastases From Gastrointestinal Stromal Tumors.

Background: The clinical benefit of hepatectomy in patients with liver metastases from gastrointestinal stromal tumors (GIST) has not been well defined in this era of tyrosine kinase inhibitor (TKI). Our study aims to demonstrate the survival advantage of adding hepatectomy in patients with GIST liver metastases. Methods: Information on patients with metastatic GIST treated or consulted between January 2006 and December 2018 was retrieved. Patients without extrahepatic metastases were included and classified into the surgical (S group) and non-surgical (NS group). Clinicopathological features were compared and their association with survival was assessed. Results: A total of 119 patients were included in this retrospective analysis, 62 in the S group and 59 in the NS group. Comparison of clinicopathological features showed that a markedly higher proportion of patients in the S group had ≤3 hepatic lesions (79.0% vs. 29.8%, p<0.001). After a median follow-up duration of 56 months, patients in the S group had significantly better progression-free survival (PFS) and marginally improved overall survival (OS) than those in the NS group (3y PFS:86.2% vs. 64.6%, p=0.002; 5y OS: 91.5% vs. 78.3%, p=0.083). After propensity score matching, multivariate analysis identified hepatectomy as the only significant prognostic factor for PFS while age, hepatectomy and max tumor diameter were significant predictor for OS. Conclusions: Addition of hepatectomy provided longer disease control in patients with metastatic GIST confined to the liver. Upfront hepatectomy followed by imatinib therapy is worthwhile trying in patients with single and easily removable lesions.

Clinical and Prognostic Significance of Tumor-Infiltrating CD8+ T Cells and PD-L1 Expression in Primary Gastrointestinal Stromal Tumors.

PURPOSE: Immunotherapy for gastrointestinal stromal tumors (GISTs) remains a clinical challenge. The present study aimed to explore the clinical and prognostic significance of immune cell infiltration and PD-L1 expression in GISTs. METHODS: A total of 507 clinical tissue specimens of primary GISTs were collected for immunohistochemical analysis of immune cell infiltration and PD-L1 expression. Influencing factors of survival were evaluated by Kaplan-Meier analysis. Univariate and multivariate analyses were performed using the Cox regression model. RESULTS: There were significant differences in sex, tumor location, size, mitotic index, NIH risk grade, and cell morphology between different gene mutation types of GISTs. Immune cell infiltration in GISTs mainly involved macrophages and T cells. PD-1 was expressed in 48.5% of the tissue specimens, and PD-L1 expression was detected in 46.0% of the samples. PD-L1 expression was negatively correlated with the tumor size and mitotic index but positively correlated with the number of CD8+ T cells. There were significant differences in the number of CD8+ T cells between different gene mutation types. Wild type-mutant GISTs were enriched with CD8+ T cells as compared with KIT- and PDGFRA-mutant GISTs. The number of CD8+ T cells was higher in non-gastric GISTs. PD-L1 and CD8+ T cells were independent predictors for better relapse-free survival of GISTs. CONCLUSIONS: PD-L1 expression is a predictive biomarker for better prognosis of GISTs. Non-gastric GIST patients with wild-type mutations may be the beneficiaries of PD-1/PD-L1 inhibitors.

Immune Cell Infiltration and the Expression of PD-1 and PD-L1 in Primary PDGFRA-Mutant Gastrointestinal Stromal Tumors.

PURPOSE: To characterize the immune cell profile and expression of PD-1, PD-L1, and IDO in PDGFRA-mutant gastrointestinal stromal tumors (GISTs). METHODS: The clinicopathological data of PDGFRA-mutant GIST patients who received surgical resection in Zhongshan Hospital between January 2013 and August 2019 were reviewed retrospectively. The specimens of tissue chips were detected for immune cell infiltration and the expression of PD-1, PD-L1, and IDO by immunohistochemical staining. RESULTS: CD3+, CD8+, and CD68+ cells were the main infiltrating immune cells in the 42 patients included in this study. In addition, CD4+, CD56+, Foxp3+, and CD20+ cells were also observed. A higher CD8+ T cell count was associated with smaller tumor size and PDGFRA D842V mutation (P = 0.047, P = 0.005). A higher CD3+ and CD68+ cell count was associated with a higher mitotic index (P = 0.022, P = 0.006). CD4+ and CD20+ cell count was associated with tumor morphology (P = 0.002, P = 0.045). PD-1 expression was present in 37 (88%) samples. Eighteen samples were positive for PD-L1 expression, and it was higher in small vs. large tumors (P = 0.012) and epithelioid and mixed cell type vs. spindle cell type GISTs (P = 0.046). IDO expression was positive in all 42 patients. The number of CD4+ cells was significantly greater in the specimens with high IDO expression (P = 0.012). CONCLUSION: There were abundant infiltrating immune cells in PDGFRA-mutant GISTs. PD-L1 expression was negatively associated with tumor size. The immunotherapy targeting PD-1/PD-L1 checkpoint and IDO may be valuable.

Relationship of prognostic nutritional index with prognosis of gastrointestinal stromal tumors.

Background: The prognostic nutritional index (PNI) is a useful parameter that indicates the immunonutritional status of patients with malignant tumors. In this retrospective study, we aimed to investigate the value of PNI to predict the outcome of gastrointestinal stromal tumors (GISTs). Material and methods: This study enrolled 431 GIST patients who underwent curative resection from January 2000 to December 2012. A receiver operating characteristic (ROC) curve analysis was used to identify the cutoff value of PNI, neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR). Survival curves were produced using the Kaplan-Meier method and were compared using a log-rank test. The Cox proportional hazards model was used to identify independent prognostic factors. Results: Of the 431 patients, 209 (48.5%) were male and 222 (51.5%) were female. The median age was 56 (range 20-80 years old). The PNI cutoff value was 47.45, with a sensitivity of 61.1 % and a specificity of 69.9 %. Compared to the PNI-low group (PNI < 47.45), the PNI-high group (PNI ≥47.45) had a significantly longer recurrence-free survival (RFS) (5-year RFS rate 89.9% versus 70.8%, p<0.001). Patients with higher PNI (p<0.001), lower NLR (p<0.001) and lower PLR (p=0.002) had significant better prognosis. PNI was found to be an independent prognostic factor of RFS (hazard ratio [HR] =1.967, 95% confidence interval [95% CI]: 1.243-3.114, p=0.004). Conclusions: PNI is a simple and useful marker that can predict the prognosis of GIST.

Clinical outcomes of imatinib dose escalation versus sunitinib in first-line imatinib-failure gastrointestinal stromal tumour.

AIM: The majority of available data on the clinical efficacy of sunitinib in patients with imatinib-resistant or -intolerant gastrointestinal stromal tumours (GISTs) are from studies of western populations. We investigated the clinical outcomes of imatinib dose escalation versus sunitinib in first-line imatinib-failure Asian GIST patients to further guide clinical treatment. METHODS: Patients received imatinib dose escalation and a shift to sunitinib (Group A) or a direct shift to sunitinib (Group B). The objective tumour response was assessed according to Choi's criteria. Progression-free survival (PFS) and overall survival (OS) were calculated. The relationship between genetic mutation and survival was analysed. RESULTS: In total, 40 patients who fulfilled the inclusion criteria were recruited. The differences in survival between Group A and Group B were not significant for PFS (p = .776) or OS (p = .219). For patients with KIT exon 11 mutation, a trend towards a better PFS was found in Group B (p = .122), OS of Group B was better than Group A (p = .013). The median PFS and OS of sunitinib treatment were 8 and 24 months, respectively, and a clinical benefit was observed in 80%. Patients with KIT exon 11 mutations had better PFS compared to those with KIT exon 9 mutations or wild-type GISTs (p = .017, p = .040, respectively). CONCLUSIONS: Both imatinib dose escalation and sunitinib were optional in Asian patients after failure of first-line imatinib, and patients with KIT exon 11 mutation benefited more from a direct shift to sunitinib.

The prognostic value of neutrophil-lymphocyte ratio is superior to derived neutrophil-lymphocyte ratio in advanced gastric cancer treated with preoperative chemotherapy and sequential R0 resection: a 5-year follow-up.

AIM: The role of neutrophil-lymphocyte ratio (NLR) and derived neutrophil-lymphocyte ratio (d-NLR) in outcome prediction is assessed in patients with advanced gastric cancer receiving preoperative chemotherapy in a 5-year follow-up cohort. PATIENTS AND METHODS: Patients undergoing preoperative chemotherapy and sequential R0 resection for advanced gastric cancer were enrolled from July 2004 to November 2011. Wilcoxon matched-pairs signed-rank test was used to evaluate the change of peripheral blood parameters. Receiver operating curve was used to identify the optimal cutoff values of NLR and d-NLR. Survival function was analyzed using Kaplan-Meier curves and Cox proportional hazard model. RESULTS: Significant difference was found between baseline and post-chemotherapy blood parameters, including leukocytes, neutrophils, lymphocytes, NLR and d-NLR (all P<0.05). High baseline NLR group (NLR ≥2.230) had a significant shorter recurrence-free survival (RFS) (hazard ratio [HR] =1.814, 95% confidence interval [95% CI]: 1.112-2.960, P=0.015) and shorter overall survival (OS) (HR =1.867, 95% CI: 1.129-3.089, P=0.013) than those of the low baseline NLR group (NLR <2.230). High baseline d-NLR group (d-NLR ≥1.885) also had a shorter RFS (HR =1.805, 95% CI: 1.116-2.919, P=0.014) and shorter OS (HR =1.783, 95% CI: 1.091-2.916, P=0.019) than those of the low baseline d-NLR group (d-NLR <1.885). However, post-chemotherapy NLR and d-NLR showed no prognostic significance on RFS and OS (all P>0.05). Multivariate analysis showed that higher baseline NLR but not d-NLR was identified as an independent factor associated with worse RFS (HR =1.707, 95% CI: 1.042-2.797, P=0.034) and worse OS (HR =1.758, 95% CI: 1.058-2.919, P=0.029). CONCLUSION: Baseline NLR and d-NLR may serve as convenient, easily measured prognostic indicators in advanced gastric cancer treated with preoperative chemotherapy and sequential R0 resection, especially to baseline NLR, which showed independent prognostic significance on RFS and OS, while post-chemotherapy NLR and d-NLR lost their usefulness due to the inhibition of bone marrow hematopoietic function. Patients with high baseline NLR and d-NLR values need multimodal therapy.

Value of the prognostic nutritional index in advanced gastric cancer treated with preoperative chemotherapy.

BACKGROUND: The prognostic nutritional index (PNI) is a useful parameter indicating the immune and nutritional status of cancer patients; this study investigated the prognostic value of the PNI in advanced gastric cancer patients treated with preoperative chemotherapy. MATERIALS AND METHODS: We retrospectively reviewed 117 advanced gastric cancer patients who met the inclusion criteria for preoperative chemotherapy and underwent surgical resection from July 2004 to December 2011. The patients were divided into PNI-high (PNI ≥ 45) and PNI-low (PNI < 45) groups. Clinicopathologic features, chemotherapy adverse events, and surgical complications were compared between the prechemotherapy PNI-high and PNI-low groups using the chi-square test. Survival analysis was performed using the Kaplan-Meier method and log-rank test. The Cox proportional hazard model was used to identify prognostic factors. RESULTS: Overall survival was better in the prechemotherapy PNI-high group than in the PNI-low group (hazard ratio [HR] = 2.237, 95% confidence interval [CI]: 1.271-3.393, P = 0.005), while there was no significant difference in Overall survival between the postchemotherapy PNI-high and PNI-low groups (P > 0.05). Cox regression analysis indicated that yield pathologic T (ypT), yield pathologic N (ypN) stage, and prechemotherapy PNI were independent prognostic factors (ypT: HR = 2.914, 95% CI = 1.312-6.470, P = 0.009; ypN: HR = 4.909, 95% CI = 1.764-13.660, P = 0.003; prechemotherapy PNI: HR = 1.963, 95% CI = 1.101-3.499, P = 0.022). CONCLUSIONS: The prechemotherapy PNI is a useful predictor of the long-term outcome of patients with advanced gastric cancer treated with preoperative chemotherapy.

Papillary Thyroid Carcinoma Treated with Radiofrequency Ablation in a Patient with Hypertrophic Cardiomyopathy: A Case Report.

Standard therapy has not been established for thyroid cancer when a thyroidectomy is contraindicated due to systemic disease. Herein, we reported a patient who had hypertrophic cardiomyopathy and papillary thyroid carcinoma treated by radiofrequency ablation because of inability to tolerate a thyroidectomy. Radiofrequency ablation can be used to treat thyroid cancer when surgery is not feasible, although the long-term outcome needs further observation.

Primary gastrointestinal stromal tumor of the liver treated with sequential therapy.

A 67-year-old female presented with a primary hepatic gastrointestinal stromal tumor that was detected by computed tomography and diagnosed based on histopathological and genetic analyses. The tumor was microscopically composed of spindle cells and epithelioid cells, and immunohistochemistry results showed positive staining for CD117 and CD34 expression. A genetic analysis revealed a heterozygous point mutation and deletion in exon 11 of c-KIT. After an R0 resection, imatinib mesylate was administered for 1 year until its use was discontinued due to severe side effects. Two years after the original operation, the tumor recurred in the residual liver and was completely resected again. Imatinib mesylate was administered for 2 years until it was replaced by sunitinib malate because of disease progression. The patient has survived for 53 mo after undergoing a sequential therapy consisting of surgical excision, imatinib and sunitinib.

Intratumor IL-17-positive mast cells are the major source of the IL-17 that is predictive of survival in gastric cancer patients.

Interleukin-17 (IL-17) is prevalent in tumor tissue and suppresses effective anti-tumor immune responses. However, the source of the increased tumor-infiltrating IL-17 and its contribution to tumor progression in human gastric cancer remain poorly understood. In this study, we enrolled 112 gastric cancer patients, immunofluorescence was used to evaluate the colocalization of CD3, CD4, CD56, CD20, CD68, and mast cell tryptase (MCT) with IL-17. Immunohistochemistry was used to evaluate the distribution of microvessel density (CD34), CD66b(+), CD68(+), and FoxP3(+) cells in different microanatomical areas. Prognostic value was determined by Kaplan-Meier analysis and a Cox regression model. The results showed that mast cells, but not T cells or macrophages, were the predominant cell type producing IL-17 in gastric cancer. Significant positive correlations were detected between densities of mast cell-derived IL-17 and microvessels, neutrophils, and regulatory T cells (Tregs). Furthermore, we found that the majority of vascular endothelial cells expressing Interleukin-17 receptor (IL-17R). Kaplan-Meier analysis revealed that increasing intratumor infiltrated mast cells and IL-17(+) cells, as well as MCT(+) IL-17(+) cells, were significantly associated with worse overall survival. These findings indicated that mast cells were the major source of IL-17 in gastric cancer, and intratumor IL-17 infiltration may have promoted tumor progression by enhancing angiogenesis in the tumor microenvironment through the axis of IL-17/IL-17R. IL-17-positive mast cells showed a prognostic factor in gastric cancer, indicating that immunotherapy targeting mast cells might be an effective strategy to control intratumor IL-17 infiltration, and consequently reverse immunosuppression in the tumor microenvironment, facilitating cancer immunotherapy.

Role of plasmacytoid dendritic cells and inducible costimulator-positive regulatory T cells in the immunosuppression microenvironment of gastric cancer.

Regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs) play important roles in the immune escape of cancer. In this study, we investigated pDCs and pDC-induced inducible costimulator (ICOS)(+) Treg populations in peripheral blood from gastric cancer (GC) patients and healthy donors by flow cytometry. The distribution of these cells in carcinoma tissue, peritumor tissue, and normal gastric mucosa was detected by immunohistochemistry. Plasma and tissue concentration of the cytokines such as interleukin-10 and transforming growth factor-ß1 were also measured. We found that the numbers of pDCs, Tregs, and ICOS(+) Tregs in peripheral blood were increased in GC patients compared with healthy donors. In tissue, Tregs and ICOS(+) Tregs were found distributing mainly in carcinoma tissue, whereas pDCs were mainly found in peritumor tissue. Moreover, the Foxp3(+) ICOS(+) /Foxp3(+) cell ratio in carcinoma and peritumor tissue were higher than that in normal tissue. There were more ICOS(+) Tregs in tumor and peritumor tissue of late-stage GC patients. There was a positive correlation between pDCs and ICOS(+) Tregs in peripheral blood and peritumor tissue from GC patients. In conclusion, pDCs may play a potential role in recruiting ICOS(+) Tregs, and both participate in the immunosuppression microenvironment of GC.

Enhancing catalytic activity of a hybrid xylanase through single substitution of Leu to Pro near the active site.

A modified error-prone PCR and high-throughout screening system based on 96-well plate were employed to improve catalytic activity of a hybrid xylanase (ATx). The mutant (FSI-A124) with enhanced activity was further heterologously expressed in Pichia pastoris under the control of GAP promoter. The recombinant xylanase driven by the Saccharomyces cerevisiae α-mating factor was secreted into culture medium. After growth in YPD medium for 96 h, xylanase activity in the culture supernatant reached 66.1 U ml(-1), which was 2.92 times as that of its parent. 6 × His-tagged purification increased the specific activity to 1557.61 U mg(-1). The optimum temperature and pH of recombinant xylanase were 55°C and 6.0, respectively. A single amino acid substitution (L49P) was observed within sequence of the mutant. Insight of the three dimensional structure revealed that proline possibly produced weaker hydrogen bond, van der Waals force and hydrophobic interaction with other residues nearby than leucine, especially for V174, contributing to the flexibility of catalytic residue E177. In this study, FSI-A124 exhibited higher xylanase activity but poorer thermostability than its parent, indicating that activity and stability might be negatively correlated.

Identification and proteomic analysis of a novel gossypol-degrading fungal strain.

BACKGROUND: Cottonseed meal, an important source of feed raw materials, has limited use in the feed industry because of the presence of the highly toxic gossypol. The aim of the current work was to isolate the gossypol-degrading fungus from a soil microcosm and investigate the proteins involved in gossypol degradation. RESULTS: A fungal strain, AN-1, that uses gossypol as its sole carbon source was isolated and identified as Aspergillus niger. A large number of intracellular proteins were detected using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but no significant difference was observed between the glucose-containing and gossypol-containing mycelium extracts. Two-dimensional gel electrophoresis results showed that the protein spots were concentrated in the 25.0-66.2 kDa range and distributed in different pI gradients. PDQuest software showed that 51 protein spots in the gels were differentially expressed. Of these, 20 differential protein spots, including six special spots expressed in gossypol, were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CONCLUSION: The fungus AN-1 biodegraded gossypol and the proteomic analysis results indicate that some proteins were involved in the gossypol biodegradation during fungus survival, using gossypol as its sole carbon source.

Effects of zinc supplementation and deficiency on bone metabolism and related gene expression in rat.

One hundred male rats were randomly divided into four groups (n = 25) and fed a Zn-adequate diet (ZA, 46.39 mg/kg), Zn-deficient diet (ZD, 3.20 mg/kg), Zn-overdose diet (ZO, 234.39 mg/kg), or were pair-fed a Zn-adequate diet (PF) for 5 weeks, respectively. The body weight, femur weight, and activity of alkaline phosphatase (ALP) were reduced in the ZD group but were increased in the ZO group. Zn concentrations in both liver and femur were elevated in the ZO group, whereas femur Zn was decreased in the ZD group. The concentrations of calcium and phosphorus were lower in the ZD than those in other groups. Serum calcium concentration was decreased in the ZD. The relative expression level of ALP was decreased in both ZD and PF, and no significant differences were observed between ZO and ZA. Insulin-like growth factor-I (IGF-I) mRNA level was reduced in the ZD but unchanged in the ZO and PF group. Zn deficiency also decreased ALP mRNA level as compared with that of PF group. Carbonic anhydrase II mRNA level was not affected by Zn. Nevertheless, dietary Zn influenced the growth, bone metabolism, and expression of IGF-I and ALP in male growing rats.

Hydrolytic properties of a hybrid xylanase and its parents.

The hydrolytic properties of a hybrid xylanase (ATx) and its parents (reAnxA and reTfxA) were studied using xylans and xylooligosaccharides as substrates. Analysis of reaction mixtures by high-performance liquid chromatograph revealed that xylotriose (X3) was the main product released from birchwood xylan and wheat bran insoluble xylan by ATx and reAnxA, respectively. Xylobiose (X2) was the main product separately released from birchwood xylan and wheat bran insoluble xylan by reTfxA. Xylotetraose (X4), xylopentaose (X5), and xylohexaose (X6) could be hydrolyzed by ATx, which showed no activity on X2 and X3. Therefore, X4 might be the minimum oligomer hydrolyzed by ATx. X2-X6 could be hydrolyzed by reAnxA and reTfxA, respectively. All of ATx, reAnxA, and reTfxA showed transglycosylation activity.

Bacillus phytases: present scenario and future perspectives.

Phytases are a special class of phosphatases that catalyze the sequential hydrolysis of phytate to less-phosphorylated myo-inositol derivatives and inorganic phosphate. Bacillus phytases, which exhibit their desirable activity profile under neutral pH, higher thermal stability, and strict substrate specificity for the calcium-phytate complex, have considerable potential in commercial and environmental applications. This review describes recent findings concerning the production, biochemical properties, molecular characteristics, and expression of Bacillus phytases. Several potential applications of the Bacillus phytases in animal nutrition, human health, and synthesis of lower myo-inositol phosphates are also summarized.

The effect of peripheral administration of zinc on food intake in rats fed Zn-adequate or Zn-deficient diets.

Zinc deficiency induces a striking reduction of food intake in animals. To elucidate the mechanisms for this effect, two studies were connectedly conducted to determine the effects of peripheral administration of zinc on food intake in rats fed the zinc-adequate or zinc-deficient diets for a 3-week period. In study 1, two groups of male Sprague-Dawley rats were provided diets made either adequate (ZA; 38.89 mg/kg) or deficient (ZD; 3.30 mg/kg) in zinc. In study 2, after feeding for 3 weeks, both ZA and ZD groups received intraperitoneal (IP) injection of zinc solution with three levels (0.5, 1.0, and 2.0 microg zinc/g body weight, respectively) and cumulative food intake at 0.5, 1, 2, 4, and 24 h, and plasma hormones concentrations were measured. The results in study 1 showed rats fed the ZD diets revealed symptoms of zinc deficiency, such as sparse and coarse hair, poor appetite, susceptibility to surroundings, lethargy, and small movements. Zinc concentrations in serum, femur, and skeletal muscle of rats fed the ZD diets declined by 26.58% (P < 0.01), 27.32% (P < 0.01), and 24.22% (P < 0.05), respectively, as compared with ZA control group. These findings demonstrated that rat models with zinc deficiency and zinc adequacy had been fully established. The results in study 2 showed that IP administration of zinc in both ZA and ZD rats did not influence food intake at each time points (P > 0.05), although zinc deficiency suppressed food intake. Plasma neuropeptide Y (NPY) was higher, but insulin and glucagon were lower in response to zinc deficiency or zinc administration by contrast with their respective controls (P < 0.05). Leptin, T3, and T4 concentrations were uniformly decreased (P < 0.05) in rats fed the ZD diets in contrast to ZA diets; however, no differences (P > 0.05) were observed during zinc injection. Calcitonin gene-related peptide was unaffected (P > 0.05) by either zinc deficiency or zinc administration. The present studies suggested that zinc administration did not affect short-term food intake in rats even in the zinc-deficient ones; the reduced food intake induced by zinc deficiency was probably associated with the depression in thyroid hormones. The results also indicated that NPY and insulin varied conversely during the control of food intake.