Screening, identification, purification and homologous modeling of marine cold-active alpha-amylase

BACKGROUND

Cold-active α-amylase is essential in industrial production. However, the number of cold-active α-amylases available for use is limited. Screening microbial strains would lay the groundwork for the future development of the food and pharmaceutical industries.

OBJECTIVE

To screen microbial strains for cold-active α-amylase based on physiological and biochemical identification, as well as homology modelling.

MATERIALS AND METHODS

Cold-active α-amylase strains were screened from water and mud obtained from the Yellow Sea. Colony morphology, Gram staining, scanning electron microscopy and transmission electron microscopy, physiological and biochemical identification and 16S rRNA gene analysis were used to identify strains. A series of steps, including DEAE-anion exchange column chromatography, SephadexG-100 column chromatography, and SDS-PAGE electrophoresis, were used to produce cold-active α-amylase of relatively high purity. Finally, the homology of amylase was modeled to explore the structure and activity site of the enzyme.

RESULTS

The named dsh19-1 strain of cold-active α-amylase was screened and identified as Bacillus. The cold-active α-amylase produced by Bacillus was named AmyD-1. The protein with PDB sequence number 5A2B was found to have 40.6% homology with AmyD-1. The verification score of the 3-D model was 137.07 points. We discovered that the six sites are potential sites for amylase to decompose starch by building a 3-D AmyD-1 model. AmyD-1 has a molecular weight of 1515 bp, and hydrogen bonding may be the primary interaction force between AmyD-1 and glucose molecules.

CONCLUSION

A cold-active α-amylase produced by Bacillus strain dsh19-1 was successfully obtained and named AmyD-1. This enzyme has potential uses in the food and pharmaceutical industries.

Amiloride, a urokinase-type plasminogen activator receptor (uTPA) inhibitor, reduces proteinurea in podocytes

This study examined the mechanism of action of amiloride, a urokinase-type plasminogen activator receptor inhibitor, in lowering proteinuria. Podocytes were resuscitated to allow for their proliferation and were observed for morphological changes. In the in vitro experiment, control, lipopolysaccharide, and lipopolysaccharide + amiloride groups were established. The expression of urokinase-type plasminogen activator receptor (uPAR) in podocytes was detected with a flow cytometer and cell motility was detected with the transwell migration assay. In the in vivo test, the urine protein volume of the model was detected at 24 h using Coomassie brilliant blue staining and the morphological changes of the podocytes were detected with immunofluorescence. The protein expression rate of uPAR in the lipopolysaccharide group was significantly higher than those in the control and lipopolysaccharide + amiloride groups (P < 0.05). The viability of cells in the lipopolysaccharide group was significantly higher than those in the control and lipopolysaccharide + amiloride groups (P < 0.05). Compared with the urine protein level in the control group at 24 h, the level in the lipopolysaccharide group increased significantly (P < 0.05), whereas compared with the urine protein level in the lipopolysaccharide group, the level in the lipopolysaccharide + amiloride group decreased (P < 0.05). uPAR expression was significantly downregulated, and the fusion of the podocyte-specific skelemin synaptopodin on the glomerulus podocytes was significantly decreased in the lipopolysaccharide + amiloride group. These results suggest that amiloride is able to reduce cell motility and thus lower proteinuria by inhibiting the expression of uPAR in podocytes.

Vaccines targeting tumor blood vessel antigens promote CD8(+) T cell-dependent tumor eradication or dormancy in HLA-A2 transgenic mice

We have recently shown that effective cytokine gene therapy of solid tumors in HLA-A2 transgenic (HHD) mice lacking murine MHC class I molecule expression results in the generation of HLA-A2-restricted CD8(+) T effector cells selectively recognizing tumor blood vessel-associated pericytes and/or vascular endothelial cells. Using an HHD model in which HLA-A2(neg) tumor (MC38 colon carcinoma or B16 melanoma) cells are not recognized by the CD8(+) T cell repertoire, we now show that vaccines on the basis of tumor-associated blood vessel Ags (TBVA) elicit protective Tc1-dependent immunity capable of mediating tumor regression or extending overall survival. Vaccine efficacy was not observed if (HLA-A2(neg)) wild-type C57BL/6 mice were instead used as recipient animals. In the HHD model, effective vaccination resulted in profound infiltration of tumor lesions by CD8(+) (but not CD4(+)) T cells, in a coordinate reduction of CD31(+) blood vessels in the tumor microenvironment, and in the "spreading" of CD8(+) T cell responses to alternate TBVA that were not intrinsic to the vaccine. Protective Tc1-mediated immunity was durable and directly recognized pericytes and/or vascular endothelial cells flow-sorted from tumor tissue but not from tumor-uninvolved normal kidneys harvested from these same animals. Strikingly, the depletion of CD8(+), but not CD4(+), T cells at late time points after effective therapy frequently resulted in the recurrence of disease at the site of the regressed primary lesion. This suggests that the vaccine-induced anti-TBVA T cell repertoire can mediate the clinically preferred outcomes of either effectively eradicating tumors or policing a state of (occult) tumor dormancy.

Abstract 3466: Tumor pericytes: A novel target for immune therapy in renal cell carcinoma

Tumor vasculature is classified by leaky, chaotic blood vessels consisting of several components including vascular endothelial cells (VEC) and mural cells (smooth muscle cells and pericytes), as well as immune regulatory cells, stem cells and vascular progenitors. Irregular tumor vasculature limits immune effector cell access to the tumor, and may in part be responsible for the modest success observed in many current anti-cancer immunotherapies. Certain drugs targeting tyrosine kinase receptors expressed on tumor stromal cells induce a Type-1 proinflammatory skewing of the tumor microenvironment (TME) with a coordinate reduction in the number of immune regulatory cell populations. A transient normalization of the vasculature may also occur in association with enhanced leukocyte recruitment. We have shown that vaccination against tumor-associated stromal antigens leads to the activation of VCAM-1 expression on tumor vascular endothelial cells and the enhanced recruitment of protective Type-1 T cells into the TME. Currently little is known regarding pericyte biology and their behavior in the TME, with no existing treatments specifically targeting pericytes. We hypothesize that pericytes residing in the TME differentially express antigens that distinguish them from pericytes in healthy tissue, and vaccination specifically targeting tumor pericyte antigens will result in vascular normalization and improved delivery of protective Type-1 T cells into the TME. To address these hypotheses, we examined mRNA expression of pericytes and VEC that have been flow-sorted from human renal cell carcinoma (RCC) tumors and patient-matched normal adjacent kidney (NAK) tissue. We have identified antigens that are differentially expressed by pericytes and/or by VEC in the TME versus NAK (such as RGS5). We are currently investigating the therapeutic efficacy of genetic (lentiviral) vaccines encoding tumor-associated stromal antigens in murine tumor models.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3466. doi:10.1158/1538-7445.AM2011-3466

Update on vaccine development for renal cell cancer

Renal cell carcinoma (RCC) remains a significant health concern that frequently presents as metastatic disease at the time of initial diagnosis. Current first-line therapeutics for the advanced-stage RCC include antiangiogenic drugs that have yielded high rates of objective clinical response; however, these tend to be transient in nature, with many patients becoming refractory to chronic treatment with these agents. Adjuvant immunotherapies remain viable candidates to sustain disease-free and overall patient survival. In particular, vaccines designed to optimize the activation, maintenance, and recruitment of specific immunity within or into the tumor site continue to evolve. Based on the integration of increasingly refined immunomonitoring systems in both translational models and clinical trials, allowing for the improved understanding of treatment mechanism(s) of action, further refined (combinational) vaccine protocols are currently being developed and evaluated. This review provides a brief history of RCC vaccine development, discusses the successes and limitations in such approaches, and provides a rationale for developing combinational vaccine approaches that may provide improved clinical benefits to patients with RCC.

Immunogenicity of umbilical cord tissue–derived cells

Umbilical cord tissue provides a unique source of cells with potential for tissue repair. Umbilical cord tissue–derived cells (UTCs) are MHC class I (MHCI) dull and negative for MHC class II (MHCII), but can be activated to increase MHCI and to express MHCII with IFN-γ stimulation. Mesenchymal stem cells with similar characteristics have been inferred to be nonimmunogenic; however, in most cases, immunogenicity was not directly assessed. Using UTC from Massachusetts General Hospital MHC-defined miniature swine, we assessed immunogenicity across a full MHC barrier. Immunogenicity was assessed by in vitro assays including mixed lymphocyte reaction (MLR) and flow cytometry to detect serum alloantibody. A single injection of MHC-mismatched unactivated UTCs did not induce a detectable immune response. When injected in an inflamed region, injected repeatedly in the same region or stimulated with IFN-γ prior to injection, UTCs were immunogenic. As clinical cellular repair strategies may involve injection of allogeneic cells into inflamed regions of damaged tissue or repeated doses of cells to achieve the desired benefit, our results on the immunogenicity of these cells in these circumstances may have important implications for optimal success and functional improvement for this cellular treatment strategy for diseased tissues.

Optical node with time-space-and-wavelength domain contention resolution, deflection and dropping capability

We experimentally demonstrate an optical node with time-space-and- wavelength domain contention resolution, deflection and dropping capability. The node is composed of an optical buffer based on an optical crossconnect and a wavelength converter. Although the experimental results are shown at 10 Gbit/s the bitrate can be increased substantially. Bit-error rate measurements are shown, sustaining only 3.5 dB power penalty after 10mus of optical buffering and agile wavelength conversion over 18nm span.

Restoration of immunity in lymphopenic individuals with cancer by vaccination and adoptive T-cell transfer

Immunodeficiency is a barrier to successful vaccination in individuals with cancer and chronic infection. We performed a randomized phase 1/2 study in lymphopenic individuals after high-dose chemotherapy and autologous hematopoietic stem cell transplantation for myeloma. Combination immunotherapy consisting of a single early post-transplant infusion of in vivo vaccine-primed and ex vivo costimulated autologous T cells followed by post-transplant booster immunizations improved the severe immunodeficiency associated with high-dose chemotherapy and led to the induction of clinically relevant immunity in adults within a month after transplantation. Immune assays showed accelerated restoration of CD4 T-cell numbers and function. Early T-cell infusions also resulted in significantly improved T-cell proliferation in response to antigens that were not contained in the vaccine, as assessed by responses to staphylococcal enterotoxin B and cytomegalovirus antigens (P < 0.05). In the setting of lymphopenia, combined vaccine therapy and adoptive T-cell transfer fosters the development of enhanced memory T-cell responses.

7x 40 Gb/s base-rate RZ all-optical broadcasting utilizing an electroabsorption modulator

We experimentally demonstrate all-optical broadcasting through simultaneous 7 x 40 Gb/s base-rate wavelength conversion in RZ format based on cross absorption modulation in an electroabsorption modulator. In this experiment the original intensity-modulated information is successfully duplicated onto seven wavelengths that comply with the ITU-T proposal. The advantages of the proposed wavelength conversion scheme are also discussed.

Biochemical evidence of thiamine depletion during the Cuban neuropathy epidemic, 1992-1993

During an epidemic outbreak of neuropathy in Cuba during 1992-1993, blood and urine samples were collected from 107 persons with confirmed neuropathy, from 106 control subjects without clinical abnormality who were broadly matched with the affected persons by age and domicile, and from 537 unmatched subjects, also free from clinical abnormality. The unmatched subjects lived in two locations in Cuba; at each location they were drawn from two age ranges: 11-15-y-old secondary school students and 16-64-y-old adults. Measurements of urinary thiamine and blood transketolase and its activation with thiamine pyrophosphate were made. For the neuropathy subjects, these measurements were repeated after 3 wk of rehabilitation. All groups showed biochemical evidence of thiamine depletion affecting 30-70% of their members, which is a high prevalence. Severity of biochemical depletion was, however, no greater in the neuropathy subjects than in the control subjects (P > 0.05). However, it was greater in Pinar del Rio, where the incidence of disease was higher, than in the city of Havana, where less disease was seen. Although the majority of the affected subjects responded biochemically to a daily oral multivitamin supplement containing thiamine (P < 0.001), in some cases normal biochemical status was not achieved even after 3 wk of intensive treatment. In the affected group, thiamine status was inversely correlated with the amount of alcohol consumed (P = 0.007). Thiamine status at the outset was correlated with clinical outcome after treatment. Although neither thiamine depletion nor alcohol abuse were likely to have been the sole cause of the neuropathy epidemic, they may have been contributory factors. Thiamine supplementation or food fortification may therefore be necessary in Cuba.