Control of postharvest decay on cherry tomatoes by marine yeast Rhodosporidium paludigenum and calcium chloride

AIMS

In this study, the potential of calcium chloride (CaCl(2)) application to improve the efficacy of the marine antagonist Rhodosporidium paludigenum in controlling postharvest diseases of cherry tomatoes was assessed.

METHODS AND RESULTS

CaCl(2) alone was found not to have any direct influence on the population growth of R. paludigenum in NYDB cultures or in cherry tomato wounds. However, the combined treatments with 1 x 10(8) cells ml(-1)R. paludigenum and CaCl(2) at the concentration from 0.5 to 2% showed high activities to reduce black rot caused by Alternaria alternata in cherry tomato wounds, significantly higher than those of R. paludigenum or CaCl(2) alone. Meanwhile, 0.5% CaCl(2) in combination with 1 x 10(8) cells ml(-1)R. paludigenum greatly inhibited the natural decay of cherry tomatoes in 21 days' storage at 25 degrees C.

CONCLUSIONS

The combination of R. paludigenum and CaCl(2) enhances the inhibition of black rot and natural decay of postharvest cherry tomatoes. The results from this study provide a new way to improve the efficiency of R. paludigenum in maintaining the quality of postharvest fruits and vegetables.

SIGNIFICANCE AND IMPACT OF THE STUDY

The marine yeast R. paludigenum combined with CaCl(2) has greatly potential use as an alternative to chemical fungicides in inhibiting postharvest decay on cherry tomatoes.

Experimental and Numerical Study of Improving Heavy Oil Recovery by Alkaline Flooding in Sandpacks

Abstract

Chemical flooding has great potential for enhancing heavy oil recovery, especially for reservoirs where thermal methods are not feasible. It has been shown that the formation of emulsions during chemical flooding can effectively improve sweep efficiency and, consequently, increase heavy oil recovery. The mechanism of flow of oil-in-water (O/W) emulsion in porous media has been extensively studied and simulated using the filtration theory. Few studies have been done for the modelling of water-in-oil (W/O) emulsion flow in heavy oil reservoirs. This study experimentally investigated the effective viscosity of W/O emulsion in porous media. Alkaline flooding tests were performed in channelled sandpacks to demonstrate the effectiveness of sweep efficiency improvement by the in-situ produced W/O emulsions. High tertiary oil recoveries were obtained for all these tests. The alkaline flooding process was simulated by including the observed flow behaviour of extra resistance to water phase flow caused by the formation of W/O emulsions, as well as the adsorption of chemicals, interfacial tension reduction, and in-situ generation of W/O emulsions. These laboratory results and the developed simulation technique are proposed as an improvement to the simulation and design of the field-scale projects of chemical flooding for heavy oil recovery.

Introduction

Many heavy oil reservoirs in Western Canada are not suitable for steam injection techniques due to thin pay thickness. Both field and laboratory results demonstrate that waterflooding of heavy oil reservoirs can only achieve a very low oil recovery. The main causes for the poor sweep efficiency of waterflooding for these heavy oil reservoirs are very adverse mobility ratio, natural area and vertical reservoir heterogeneity and heterogeneity induced by primary production(1,2). Therefore, improving mobility ratio and blocking water flow through channels are essential for improving heavy oil recovery. The in-situ formation of emulsions during alkaline flooding has been recognized as one of the efficient methods to improve sweep efficiency for heavy oil recovery(3,4,5).

The effectiveness of alkaline flooding for acidic crudes was recognized as early as in the 1920s(6). Jennings et al.(3) proposed the mechanism of emulsification and entrapment for alkaline flooding. They carried out caustic flooding tests using a heavy oil. Their results showed that the in-situ produced O/W emulsions tended to plug water fingering and channels, resulting in improved sweep efficiency. Johnson(7) summarized possible mechanisms of alkaline flooding to improve oil recovery: dispersion and entrainment, wettability reversal, and emulsification and entrapment. The formation of W/O emulsions was also observed as a mechanism of improving oil recovery(8,9).

Seasonal variation in prey abundance influences habitat use by greater horseshoe bats (Rhinolophus ferrumequinum) in a temperate deciduous forest

The hypothesis that patterns of habitat selection of greater horseshoe bats ( Rhinolophus ferrumequinum (Schreber, 1774)) vary across seasons in a temperate deciduous forest was investigated. Variables associated with potentially important ecological factors for greater horseshoe bats (physical structure of shrub stratum, crown canopy, insect availability, lunar phase, and weather) were collected for different seasons, and 75 sampling sites were established in the Luotong Mountain Nature Reserve in northeast China. Insect abundance was highest in late summer and lowest in late autumn. Poisson generalized linear models showed that the activity of greater horseshoe bats was positively related to the height and density of shrub stratum in late summer, whereas the activity of greater horseshoe bats was associated with insect abundance in early and late autumn. During periods of intermediate prey abundance (early summer), the height and density of shrub stratum, as well as insect abundance, influenced the activity of greater horseshoe bats. Shrub stratum may provide shelter against predation for foraging greater horseshoe bats. These results support our prediction that there was a trade-off between importance of food and cover among seasons for foraging bats. These findings are useful for the conservation and management of greater horseshoe bats.

Induction of tumoricidal activity in mouse peritoneal macrophages by ginseng polysaccharide

This study examined the effects of ginseng polysaccharide (GPS) on mouse peritoneal macrophage (PM)-mediated cytotoxicity towards K562, HL-60, or KG1alpha cells. GPS had no direct effect on killing of tumor cells. However, when mouse PMs were treated with GPS, cytotoxic activity against K562, HL-60, or KG1alpha cells was significantly induced. In addition, phagocytic activity was enhanced in GPS-treated mouse PMs compared to the control. The expressions of CD(68), ACP and alpha-ANE in mouse PMs were increased by the treatment with GPS. Moreover, the levels of cytokines, including tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), IL-6 were increased and the production of nitric oxide (NO) was enhanced. Taken together, these results suggest that GPS possess a potent antitumor activity by stimulating macrophage and a potentiality as an immunomodulator against diseases such as cancer.

c-Abl and Arg tyrosine kinases regulate lysosomal degradation of the oncoprotein Galectin-3

Galectin-3 (Gal3) has important roles in tumor transformation and metastasis. This study shows that c-Abl and Abl-related gene (Arg) associate with and phosphorylate Gal3. The SH (Src homology)3 domains of c-Abl/Arg bind to a P(80)GPPSGP motif of Gal3, and Tyr79 and Tyr118 are the major tyrosine phosphorylation sites. A consequence of this interaction and phosphorylation is the significant impairment of chaperone-mediated autophagy of Gal3. Cells expressing Gal3 and treated with the c-Abl/Arg inhibitor STI571, Gal3-depleted cells, and Gal3-depleted cells expressing Gal3 phosphorylation mutants all display an increased sensitivity to apoptosis-inducing agents. In addition, tumor cells expressing the phosphorylation mutants show impaired tumorigenicity. These results partially explain the antiapoptotic effect of Abl and Arg. As tumors frequently overexpress Gal3, a c-Abl/Arg-specific inhibitor may potentially be applied along with other antitumor drugs to target the lysosomal degradation of Gal3 in tumor therapy.

Effect of manganese doping on the size effect of lead zirconate titanate thin films and the extrinsic nature of 'dead layers'

We have investigated the size effect in lead zirconate titanate (PZT) thin films with a range of manganese (Mn) doping concentrations. We found that the dynamic size effect in the conventional Pt/PZT/Pt thin-film capacitors could be systematically reduced and almost completely eliminated by increasing Mn doping concentration. The interfacial layer at the electrode-film interface appears to disappear almost entirely for the PZT films with ∼ 2% Mn doping levels, confirmed by the fits using the conventional 'in-series capacitor' model. Our work indicates that the dynamic size effect in ferroelectrics is extrinsic in nature, supporting the work by Saad et al. Other implications of our results have also been discussed. By comparing a variety of experimental studies in the literature we propose a scenario that the 'dead layer' between PZT (or barium strontium titanate, BST) and metal electrodes such as Pt and Au might have a defective pyrochlore/fluorite-like structure (possibly with a small portion of ferroelectric perovskite phase). This scenario is then generalized by including the effect of the grain-boundary dead layer on the collapse of the dielectric constant in thinner films.

Pim1 kinase synergizes with c-MYC to induce advanced prostate carcinoma

The oncogenic PIM1 kinase has been implicated as a cofactor for c-MYC in prostate carcinogenesis. In this study, we show that in human prostate tumors, coexpression of c-MYC and PIM1 is associated with higher Gleason grades. Using a tissue recombination model coupled with lentiviral-mediated gene transfer we find that Pim1 is weakly oncogenic in naive adult mouse prostatic epithelium. However, it cooperates dramatically with c-MYC to induce prostate cancer within 6-weeks. Importantly, c-MYC/Pim1 synergy is critically dependent on Pim1 kinase activity. c-MYC/Pim1 tumors showed increased levels of the active serine-62 (S62) phosphorylated form of c-MYC. Grafts expressing a phosphomimetic c-MYCS62D mutant had higher rates of proliferation than grafts expressing wild type c-MYC but did not form tumors like c-MYC/Pim1 grafts, indicating that Pim1 cooperativity with c-MYC in vivo involves additional mechanisms other than enhancement of c-MYC activity by S62 phosphorylation. c-MYC/Pim1-induced prostate carcinomas show evidence of neuroendocrine (NE) differentiation. Additional studies, including the identification of tumor cells coexpressing androgen receptor and NE cell markers synaptophysin and Ascl1 suggested that NE tumors arose from adenocarcinoma cells through transdifferentiation. These results directly show functional cooperativity between c-MYC and PIM1 in prostate tumorigenesis in vivo and support efforts for targeting PIM1 in prostate cancer.

TrkB induces EMT and has a key role in invasion of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a significant public health problem, accounting for over 5% of all cancer-related deaths, and these deaths primarily result from metastatic disease. The molecular processes involved in HNSCC pathogenesis and progression are poorly understood, and here we present experimental evidence for a direct role of the cell surface receptor tyrosine kinase, TrkB, in HNSCC tumor progression. Using immunohistochemical analysis and transcriptional profiling of archival HNSCC tumor specimens, we found that TrkB and its secreted ligand, brain-derived neurotrophic factor (BDNF), are expresses in greater than 50% of human HNSCC tumors, but not in normal upper aerodigestive tract (UADT) epithelia. Studies with HNSCC cell lines reveal that in vitro stimulation with BDNF, the ligand for TrkB, upregulates the migration and invasion of HNSCC cells, and both transient and stable suppressions of TrkB result in significant abrogation of constitutive and ligand-mediated migration and invasion. Furthermore, enforced overexpression of TrkB results in altered expression of molecular mediators of epithelial-to-mesenchymal transition (EMT), including downregulation of E-cadherin and upregulation of Twist. Using an in vivo mouse model of HNSCC, we were able to show that downregulation of TrkB suppresses tumor growth. These results directly implicate TrkB in EMT and the invasive behavior of HNSCC, and correlate with the in vivo overexpression of TrkB in human HNSCC. Taken together, these data suggest that the TrkB receptor may be a critical component in the multi-step tumor progression of HNSCC, and may be an attractive target for much needed new therapies for this disease.

HLA-mismatched hematopoietic SCT without in vitro T-cell depletion for myelodysplastic syndrome

Allogeneic hematopoietic SCT (HSCT) is currently the only curative treatment for myelodysplastic syndrome (MDS). However, many patients cannot find an HLA-matched donor. We have developed a new protocol for HLA-mismatched (including haploidentical) HSCT using G-CSF-primed BM plus G-CSF-mobilized PBSCs without in vitro T-cell depletion. A total of 36 patients diagnosed with high-risk MDS (RAEB (refractory anemia with excess blasts) or RAEBt (RAEB in transformation)) underwent transplantation from HLA-mismatched family donors. All patients achieved sustained myeloid engraftment. The cumulative incidence of grades II-IV acute GVHD (aGVHD) was 60% and that of grades III and IV aGVHD was 15%. The 2-year cumulative incidence of chronic GVHD was 56%. After a median follow-up of 17 months, 4 patients had relapsed and died and 25 patients were still alive. The 2-year probability of leukemia-free survival (LFS) was 65%. Patients transplanted within 7 months of diagnosis had better LFS (89 vs 43% ). Severe aGVHD decreased the LFS significantly by increasing non-relapse mortality (NRM). This study confirms that HLA-mismatched HSCT is a treatment option for MDS. Patients with high-risk MDS benefit from receiving HSCT early in the course of the disease.