Production of a novel bioflocculant MNXY1 by Klebsiella pneumoniae strain NY1 and application in precipitation of cyanobacteria and municipal wastewater treatment

AIMS

To isolate and characterize the novel bioflocculant-producing bacteria, to optimize the bioflocculant production and to evaluate its potential applications.

METHODS AND RESULTS

Klebsiella pneumoniae strain NY1, a bacterium that produces a novel bioflocculant (MNXY1), was selected on the chemically defined media. It was classified according to the 16S rRNA gene sequence, morphological and microscopic characteristics. MNXY1 was characterized to contain 26% protein and 66% total sugar. The constituent sugar monomers of MNXY1, revealed by NMR analysis, are glucose, galactose and quinovose. Favourable culture conditions for MNXY1 production were determined. Strain NY1 produces a high level (14.9 g l(-1)) of MNXY1. MNXY1 is thermostable and tolerant to the extreme pH. It precipitated 54% of cyanobacteria from laboratory culture and 72% of the total suspended solids from raw wastewater.

CONCLUSIONS

Strain NY1 was identified to produce a novel bioflocculant MNXY1. The outstanding performance of MNXY1 in practical applications and its availability in copious amounts make it attractive for further investigation and development for industrial scale applications.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is first report for the identification of a quinovose-containing bioflocculant and application of a protein-polysaccharide complex bioflocculant in precipitation of cyanobacteria. These findings suggest that MNXY1 holds great potential for use in management of harmful algae and city wastewater treatment.

Intestinal epithelial cells express galectin-9 in patients with food allergy that plays a critical role in sustaining allergic status in mouse intestine

BACKGROUND AND AIMS

Mechanisms in sustaining the allergic hypersensitivity status in the body are unclear. Galectin-9 (Gal-9) has strong immune regulatory capacity. The present study aims to elucidate the role of Gal-9 in sustaining allergic status in the intestine.

METHODS

Duodenal biopsies were obtained from 20 patients with peptic ulcer and food allergy (FA). The expression of Gal-9 in intestinal tissue was examined at both protein level and mRNA level. Two coculture systems with intestinal epithelial cells (IEC) and mast cells, or dendritic cells (DC) and T cells were established to investigate the source of Gal-9 in the intestine and the mechanism by which Gal-9 modulated DC's phenotyping and sustained the T helper 2 polarization.

RESULTS

Normal IEC showed mild expression of Gal-9 that was markedly enhanced in patients with FA. Mast cells had the capability to induce IEC to produce Gal-9 via releasing tryptase that activated the proteinase-activated receptor 2 on IEC. Gal-9 activated DC to produce TIM4 (T-cell immunoglobulin mucin domain) via ligating TIM3 on DC via activating the cyclic guanosine monophosphate (cGMP) pathway. In a mouse FA model, blocking Gal-9 inhibited the allergic hypersensitivity status and the antigen-specific Th2 response in the intestine.

CONCLUSIONS

IEC-derived Gal-9 contributes to sustaining the allergic status in the intestine.

Promoter hypermethylation of cyclooxygenase-2 gene in esophageal squamous cell carcinoma

Cyclooxygenase-2 (COX-2) is overexpressed in various types of human malignancies including esophageal squamous cell carcinoma (ESCC). However, a subset of ESCC either do not express COX-2 or show low level of expression. It is well established that promoter methylation is a major mechanism that mediates transcriptional silencing of COX-2 in gastric and colorectal cancer, but the data on ESCC are very limited. In this study, we attempted to determine whether COX-2 expression was also regulated by promoter methylation in human ESCC cell lines. We examined the methylation status of the COX-2 promoter in five human ESCC cell lines (EC109, EC9706, KYSE 410, KYSE 150, TE-1) using bisulfite sequencing analysis. Western blot analysis was used to determine COX-2 expression. Quantitative real-time polymerase chain reaction was used to determine COX-2 mRNA level. Prostaglandin (PG) E(2) was detected by ELISA. The promoter was densely methylated in TE-1 and KYSE 150, which had a low level of COX-2 expression and less methylated in other three cell lines (EC109, EC9706, KYSE 410), with high level of COX-2 expression. Treatment with 5-aza-deoxycytidine (5-aza-DC), a DNA methyltransferase inhibitor, demethylated the promoter and upregulated COX-2 expression, as well as PGE(2) production in TE-1 and KYSE 150. However, no such effects were observed in EC109. COX-2 protein was negative, but mRNA was positive in TE-1. After treatment with 5-aza-DC, both COX-2 mRNA and protein level had increased. These findings suggest that the promoter methylation may be one of the mechanisms that regulate COX-2 expression in ESCC.

Effect of dietary supplemental nicotinic acid on growth performance, carcass characteristics and meat quality in three genotypes of chicken

The effects of dietary supplemental nicotinic acid (NA) on growth performance, carcass characteristics and meat quality were investigated in three genotypes of chicken. Fast-growing AA (Arbor Acres) broilers were compared with two genotypes of a slow-growing local breed, Beijing-You, that had undergone selection for and against intramuscular fat content respectively (BJY+IMF and BJY-IMF). The treatments were arranged 3×4 factorial completely randomized design. Day-old females (n=624) were allocated to four treatments with six replicates per treatment and fed diets (basal contained ~25 mg NA/kg) supplemented with 0, 30, 60 and 120 mg NA/kg. A sample of 72 birds from each genotype was slaughtered at market time (8 weeks of age for AA and 16 weeks of age for BJY). The breast muscles of AA broilers were darker, had less redness and yellowness, lower drip loss and higher shear force as compared to the BJY genotypes (p<0.01). The highest drip loss and the lowest shear force among the three genotypes were apparent in BJY+IMF (p<0.01). Increasing supplementation from 0 to 60 mg NA/kg tended to increase average daily gain (ADG), average daily feed intake, width of intermuscular fat band, thickness of subcutaneous fat (including skin) and percentage of abdominal fat but, for most variables, values decreased slightly with 120 mg NA/kg. Increasing supplementation to 60 mg NA/kg decreased (quadratic, p<0.001) drip loss, but it increased at 120 mg NA/kg. The present results indicate that (i) the AA broilers fed corn-soybean meal based-diets require approximately 60 mg NA/kg to maximize ADG and meat product yield and decrease the drip loss of breast muscle; (ii) the addition of 30 mg NA/kg meets the requirement of BJY genotypes; and (iii) there seems to be no beneficial effect of NA supplementation on chicken meat quality except for limiting the drip loss.

The polymorphisms in the VHL and HIF1A genes are associated with the prognosis but not the development of renal cell carcinoma

BACKGROUND

The von Hippel-Lindau (VHL) tumor suppressor gene and hypoxia-inducible factor-1α (HIF1A) play a pivotal role in renal carcinogenesis. This study was aimed to clarify the influence of VHL and HIF1A polymorphisms on renal cell cancer (RCC) susceptibility and survival.

SUBJECTS AND METHODS

We genotyped four potentially functional single-nucleotide polymorphisms (rs779805 in VHL and rs11549465, rs11549467, and rs2057482 in HIF1A) and assessed their associations with RCC risk, clinicopathologic parameters in a case-control study of 620 patients and 623 controls, and the prognosis of RCC in a cohort of 311 patients.

RESULTS

No significant differences in VHL or HIF1A genotypes were observed between RCC cases and controls. However, individuals with ≥2 variant alleles of the four polymorphisms were associated with less frequent lymph node metastasis and lower clinical stage (P = 0.032 and P = 0.041, respectively). And the number of variant alleles was associated with improved survival in a dose-response manner (P(trend) = 0.013). Furthermore, multivariate Cox regression analysis showed that the number of variant alleles (≥1 versus 0) was an independent prognostic factor for RCC survival (P = 0.036) together with clinical stage and tumor grade.

CONCLUSION

The VHL and HIF1A polymorphisms may not influence RCC susceptibility but may jointly influence RCC progression and survival.

Transcriptional activation of the anchoring protein SAP97 by heat shock factor (HSF)-1 stabilizes K(v) 1.5 channels in HL-1 cells

BACKGROUND AND PURPOSE

The expression of voltage-dependent K⁺ channels (K_v) 1.5 is regulated by members of the heat shock protein (Hsp) family. We examined whether the heat shock transcription factor 1 (HSF-1) and its inducer geranylgeranylacetone (GGA) could affect the expression of K_v1.5 channels and its anchoring protein, synapse associated protein 97 (SAP97).

EXPERIMENTAL APPROACH

Transfected mouse atrial cardiomyocytes (HL-1 cells) and COS7 cells were subjected to luciferase reporter gene assay and whole-cell patch clamp. Protein and mRNA extracts were subjected to Western blot and quantitative real-time polymerase chain reaction.

KEY RESULTS

Heat shock of HL-1 cells induced expression of Hsp70, HSF-1, SAP97 and K_v1.5 proteins. These effects were reproduced by wild-type HSF-1. Both heat shock and expression of HSF-1, but not the R71G mutant, increased the SAP97 mRNA level. Small interfering RNA (siRNA) against SAP97 abolished HSF-1-induced increase of K_v1.5 and SAP97 proteins. A luciferase reporter gene assay revealed that the SAP97 promoter region (from −919 to −740) that contains heat shock elements (HSEs) was required for this induction. Suppression of SIRT1 function either by nicotinamide or siRNA decreased the level of SAP97 mRNA. SIRT1 activation by resveratrol had opposing effects. A treatment of the cells with GGA increased the level of SAP97 mRNA, K_v1.5 proteins and I_Kur current, which could be modified with either resveratrol or nicotinamide.

CONCLUSIONS AND IMPLICATIONS

HSF-1 induced transcription of SAP97 through SIRT1-dependent interaction with HSEs; the increase in SAP97 resulted in stabilization of K_v1.5 channels. These effects were mimicked by GGA.

Isolation and characterization of five rice telomere-associated sequences

Acoording to the telomere-repeated sequences of rice, two primers: (TTTAGGG11)(3) and (CCC-TAA.A)(3)CCC were used to amplify rice telomere-assciated sequences (TASs). Fox PCR template preparation. total DNA was digested with restrictive endonuclease and then ligated. Using the ligates or total DNA sa template, eight fragments were obtained with the single primer by the PCR reaction. To confirm that the sequences are derived from telomeric DNA, we conducted Bal31 digestion analysis. Of the eight fragments, seven were susceptible to Bal31 treatment, suggesting that they were TASs. These DNA fragments were further demonstrated u, be rice sub-telomeric sequences by RFLP mapping Five sequences have been mapped to the distal ends on rice chromme 5,6,7 and 9, and two other sequences have been mapped at interstitial sites, suggesting that (TTTAGGG)(n). also exist in the middle of rice chromosomes-All eight fragments were sequenced and characterized.

Overexpression of 14-3-3ζ in cancer cells activates PI3K via binding the p85 regulatory subunit

The ubiquitously expressed 14-3-3 proteins regulate many pathways involved in transformation. Previously, we found that 14-3-3ζ overexpression increased Akt phosphorylation in human mammary epithelial cells. Here, we investigated the clinical relevance and molecular mechanism of 14-3-3ζ overexpression-mediated Akt phosphorylation and the potential impact on breast cancer progression. We found that 14-3-3ζ overexpression was significantly (P = 0.005) associated with increased Akt phosphorylation in human breast tumors. Additionally, 14-3-3ζ overexpression combined with strong Akt phosphorylation was significantly (P=0.01) associated with increased cancer recurrence in patients. In contrast, knockdown of 14-3-3ζ expression by siRNA in cancer cell lines and tumor xenografts reduced Akt phosphorylation. Furthermore, 14-3-3ζ enhanced Akt phosphorylation through activation of PI3K. Mechanistically, 14-3-3ζ bound to the p85 regulatory subunit of PI3K and increased PI3K translocation to the cell membrane. A single 14-3-3 binding motif encompassing serine 83 on p85 is largely responsible for 14-3-3ζ-mediated p85 binding and PI3K/Akt activation. Mutation of serine 83 to alanine on p85 inhibited 14-3-3ζ binding to the p85 subunit of PI3K, reduced PI3K membrane localization and activation, impeded anchorage independent growth and enhanced stress induced apoptosis. These findings revealed a novel mechanism by which 14-3-3ζ overexpression activates PI3K, a key node in the mitogenic signaling network known to promote malignancies in many cell types.

Aldosterone perturbs adiponectin and PAI-1 expression and secretion in 3T3-L1 adipocytes

Aldosterone is considered as a new cardiovascular risk factor that plays an important role in metabolic syndrome; however, the underlying mechanism of these effects is not clear. Hypoadiponectinemia and elevated circulating concentration of plasminogen activator inhibitor-1 (PAI-1) are causally associated with obesity-related insulin resistance and cardiovascular disease. The aim of the present study is to investigate the effect of aldosterone on the production of adiponectin and PAI-1 in 3T3-L1 adipocytes. Northern and Western blot analyses revealed that aldosterone treatment inhibited adiponectin mRNA expression and secretion and simultaneously enhanced PAI-1 mRNA expression and secretion in a time- and dose-dependent manner. Rosiglitazone did not prevent aldosterone's effect on adiponectin or PAI-1 expression. In contrast, tumor necrosis factor (TNF)-α produced dramatic synergistic effects on adiponectin and PAI-1 expression when added together with aldosterone. Furthermore, the effects of aldosterone on adiponectin and PAI-1 expression appear to be mediated through glucocorticoid receptor (GR) but not mineralocorticoid receptor (MR). These results suggest that the effects of aldosterone on adiponectin and PAI-1 production are one of the underlying mechanisms linking it to insulin resistance, metabolic syndrome and cardiovascular disease.

3D double-echo steady-state with water excitation MR imaging of the intraparotid facial nerve at 1.5T: a pilot study

BACKGROUND AND PURPOSE

The intraparotid facial nerve is difficult to delineate using conventional MR sequence. Our aim was to assess the value of 3D DESSWE MR imaging in depicting the normal anatomy of the intraparotid facial nerve.

MATERIALS AND METHODS

A 3D-DESSWE sequence was performed with optimum parameters in 18 healthy volunteers on a 1.5T MR imaging unit. The data obtained were reconstructed in relation to the course of the facial nerve by using the MPR and thin-section MIP programs. Images acquired were analyzed by 2 neuroradiologists. They made the initial evaluations independently but resolved inconsistencies by collaborative review and consensus agreement. The certainty of identifying the intraparotid facial nerve was scored and recorded on an arbitrary scale of 0-2. The lengths of the facial nerves were measured; CNRs of the facial nerves and parotid ducts were calculated. Statistical evaluation of the results was achieved by the 2-tailed Wilcoxon test, ANOVA, and a paired t test.

RESULTS

In all subjects, 3D DESSWE images provided a reliable definition of the normal facial nerve anatomy bilaterally. There were no significant differences between scores, lengths, and CNRs of bilateral facial nerves (P > .05). The intraparotid facial nerve, parotid ducts, and retromandibular vein showed high signal intensity while the surrounding soft tissue showed relatively low signal intensity. The signal intensity between the facial nerves and parotid ducts was significantly different (P < .01); but no differences could be obtained for the CNRs between the 2 structures (P > .05).

CONCLUSIONS

The 3D DESSWE sequence can display the intraparotid course of the normal facial nerve, including the relationship between the facial nerve and the parotid duct.

LL-37 expression in the skin in systemic lupus erythematosus

The objective of this study was to investigate the expression and relationship of LL-37, plasmacytoid dendritic cells (pDCs) and interferon-alpha (IFN-α) in skin in systemic lupus erythematosus (SLE), and their role in SLE pathogenesis. Skin biopsies were taken from nine SLE patients and six healthy volunteers. Expression of LL-37, pDCs and IFN-α in skin specimens and consecutive sections of skin was detected with an immunohistochemical technique (IH); the expression of LL-37 and pDCs in the samples was detected with in situ hybridization (ISH). The expression levels of LL-37, pDCs and IFN-α were significantly higher in SLE skin than in that of healthy controls (p < 0.001) with either the IH or the ISH technique, and the location of positive expression in consecutive sections was similar. Correlation analysis showed that the expression levels of LL-37, pDCs and IFN-α correlated positively with each other. In conclusion, the expression of LL-37, pDCs and IFN-α was increased in the skin of patients with active SLE. It is necessary to study further the role of LL-37 in the pathogenesis of SLE, and the exact relationship among LL-37, pDCs and IFN-α.

Cell-type-specific regulation of raft-associated Akt signaling

20S-protopanaxadiol (aPPD) is a metabolite of ginseng saponins, which is reported to be pro-apoptotic in some cells but anti-apoptotic in neuronal cells by regulating Akt signaling. Owing to its cholesterol-like structure, we hypothesized that aPPD may regulate Akt signaling by interacting with lipid rafts. Here, we compared Akt signaling in glioblastoma U87MG and neuroblastoma Neuro-2a cells treated with aPPD. aPPD did not change Akt activity in the total plasma membranes of each cell type, but drastically altered the activity of raft-associated Akt. Strikingly, Akt activity was decreased in the rafts of U87MG cells but increased in N2a cells by aPPD through regulating raft-associated dephosphorylation. The bidirectional regulation of raft-associated Akt signaling by aPPD enhanced the chemotoxicity of Paclitaxel or Vinblastine in U87MG cells but attenuated the excitotoxicity of N-methyl--aspartate in N2a cells. Our results demonstrated that the activity of raft-associated but not total membrane Akt determines its cellular functions. Lipid rafts differ in different types of cells, which allows for the possibility of cell-type-specific targeting for which aPPD might prove to be a useful agent.