Baseline Sensitivity of Monilinia fructicola from China to the DMI Fungicide SYP-Z048 and Analysis of DMI-Resistant Mutants

Sterol 14α-demethylase inhibitors (DMIs) continue to be important in the management of brown rot of Monilinia spp. worldwide. In this study, the sensitivity of 100 Monilinia fructicola isolates from four unsprayed orchards and two packinghouses in Beijing, China, to the new DMI fungicide SYP-Z048 was evaluated and ranged from 0.003 to 0.039 and 0.016 to 0.047 μg/ml, respectively. Laboratory mutants resistant to SYP-Z048 were generated using UV irradiation but no mutants occurred spontaneously. Resistance was stable after 10 weekly consecutive transfers on fungicide-free medium. Three parameters, including growth rate, sporulation in vitro, and lesion area, were significantly different when sensitive isolates and resistant mutants were analyzed as groups. Mutants grew more slowly and developed significantly smaller lesions on detached fruit, and their sporulation ability in vitro was reduced. Cross resistance was found between SYP-Z048 and propiconazole (ρ = 0.82, P < 0.0001) but not between SYPZ048 and tridemorph, carbendazim, procymidone, azoxystrobin, or pyrimethanil. SYP-Z048 resistance in mutants exhibiting 50% mycelial growth inhibition values greater than 0.3 μg/ml was correlated with the presence of a mutation in the CYP51 gene that encodes the target protein for DMI fungicides. The mutation caused an amino acid change from tyrosine to phenylalanine at position 136 (Y136F). To our knowledge, this is the first baseline sensitivity of M. fructicola collected from China to a DMI fungicide. The inability of M. fructicola to generate spontaneous DMI-resistant mutants coupled with reduced fitness of Y136F mutants can explain why this target site mutation has not yet emerged as a DMI fungicide resistance determinant in M. fructicola field populations worldwide.

Implication of dysregulation of the canonical wingless-type MMTV integration site (WNT) pathway in diabetic nephropathy

AIMS/HYPOTHESIS

The wingless-type MMTV integration site (WNT) pathway mediates multiple physiological and pathological processes, such as inflammation, angiogenesis and fibrosis. The aim of this study was to investigate whether canonical WNT signalling plays a role in the pathogenesis of diabetic nephropathy.

METHODS

Expression of WNT ligands and frizzled receptors in the canonical WNT pathway in the kidney was compared at the mRNA level using real-time RT-PCR between Akita mice, streptozotocin-induced diabetic rats and db/db mice and their respective non-diabetic controls. Renal function was evaluated by measuring the urine albumin excretion. Human renal proximal tubular epithelial cells were treated with high-glucose medium and 4-hydroxynonenal (HNE). Levels of β-catenin, connective tissue growth factor and fibronectin were determined by western blot analysis.

RESULTS

Some of the WNT ligands and frizzled receptors showed increased mRNA levels in the kidneys of Akita mice, streptozotocin-induced diabetic rats and db/db mice compared with their non-diabetic controls. Renal levels of β-catenin and WNT proteins were upregulated in these diabetic models. Lowering the blood glucose levels by insulin attenuated the activation of WNT signalling in the kidneys of Akita mice. In cultured human renal proximal tubular epithelial cells, both high glucose and HNE activated WNT signalling. Inhibition of WNT signalling with a monoclonal antibody blocking LDL-receptor-related protein 6 ameliorated renal inflammation and fibrosis and reduced proteinuria in Akita mice.

CONCLUSIONS/INTERPRETATION

The WNT pathway is activated in the kidneys of models of both type 1 and 2 diabetes. Dysregulation of the WNT pathway in diabetes represents a new pathogenic mechanism of diabetic nephropathy and renders a new therapeutic target.

Molecular level dynamics of genetic oscillator--the effect of protein-protein interaction

Uncovering how interactions of a set of molecular components influence the system's dynamic behavior is important for understanding intracellular processes and elucidating design principles, but unfortunately, there are limited efforts for studying this issue. Here, we study the effect of distinct post-translational dynamics controlled by protein dimerization on oscillations in the repressilator. For this, we propose three biologically motivated model scenarios of the repressilator with monomer or dimer being the active form of repressor, and with protein-protein interactions. It is found that the dimer dissociation constant can tune oscillatory regions, frequency and amplitude. Introducing a modified linear noise approximation to evaluate fluctuations of amplitude and period in the oscillatory systems, we show that different dimerization leads to a different effect on period and amplitude in reducing noise. The manipulation of the circuit's biochemical properties provides a practical strategy for designing a robust and tunable oscillator.

Global transcriptional responses of Bacillus subtilis to xenocoumacin 1

AIMS

To determine the global transcriptional response of Bacillus subtilis to an antimicrobial agent, xenocoumacin 1 (Xcn1).

METHODS AND RESULTS

Subinhibitory concentration of Xcn1 applied to B. subtilis was measured according to Hutter's method for determining optimal concentrations. cDNA microarray technology was used to study the global transcriptional response of B. subtilis to Xcn1. Real-time RT-PCR was employed to verify alterations in the transcript levels of six genes. The subinhibitory concentration was determined to be 1 μg ml(-1). The microarray data demonstrated that Xcn1 treatment of B. subtilis led to more than a 2.0-fold up-regulation of 480 genes and more than a 2.0-fold down-regulation of 479 genes (q ≤ 0.05).

CONCLUSIONS

The transcriptional responses of B. subtilis to Xcn1 were determined, and several processes were affected by Xcn1. Additionally, cluster analysis of gene expression profiles after treatment with Xcn1 or 37 previously studied antibiotics indicated that Xcn1 has similar mechanisms of action to protein synthesis inhibitors.

SIGNIFICANCE AND IMPACT OF THE STUDY

These microarray data showed alterations of gene expression in B. subtilis after exposure to Xcn1. From the results, we identified various processes affected by Xcn1. This study provides a whole-genome perspective to elucidate the action of Xcn1 as a potential antimicrobial agent.

Efficacy of detoxification of deoxynivalenol-contaminated corn by Bacillus sp. LS100 in reducing the adverse effects of the mycotoxin on swine growth performance

Biodetoxification of mycotoxins is a novel strategy to control mycotoxicoses in animals. Bacillus sp. LS100, which transforms deoxynivalenol (DON) to a less toxic chemical de-epoxy DON (DOM-1), was evaluated for its efficacy in reducing the adverse effects of DON on swine growth performance. A feeding trial was conducted in growing pigs with four treatments: (1) corn meal without detectable DON served as control (Non-toxic Corn); (2) Fusarium-infected corn giving a toxic diet containing 5 µg DON g(-1) (Toxic Corn); (3) Toxic Corn detoxified with Bacillus sp. LS100 giving a detoxified diet containing 5 µg DOM-1 g(-1) (LS100-De-toxic Corn); (4) Non-toxic Corn treated with Bacillus sp. LS100 serving as bacterial control (LS100-Non-toxic Corn). During 9 days of exposure to the treatments, pigs on Toxic Corn showed a significant reduction in daily feed consumption, daily weight gain and feed efficiency by 29, 48 and 29%, respectively, compared to pigs on Non-toxic Corn. These parameters of the pigs fed LS100-De-toxic Corn diet were 45, 82 and 32% greater, respectively, than those of pigs fed Toxic Corn diet, and were similar to those pigs fed Non-toxic Corn and LS100-Non-toxic Corn diets. There were no significant differences between the treatments of LS100-Non-toxic Corn and Non-toxic Corn diets, implying that the bacterial isolate might not have significantly affected nutrition and palatability of the feed or had negative effects on the pig's feeding performance. The results have proved that microbial detoxification of DON in contaminated feed can eliminate negative effects of the mycotoxin, and the pre-feeding detoxification approach may be applied in the livestock industry.

Impact of depression mood disorder on the adverse drug reaction incidence rate of anticancer drugs in cancer patients

The aim of this study was to explore the impact of depression mood disorder on the incidence of adverse drug reactions of anticancer drugs in cancer patients. The Hamilton Depression Scale 17 was used to evaluate the depression mood disorder level in 73 cancer patients before chemotherapy. Pharmacists monitored adverse drug reactions during the chemotherapy period. The relationship between depression mood disorder level and the incidence of adverse drug reactions was analysed. The frequency and extent of total adverse drug reactions were not related to depression mood disorder level. The frequency and extent of subjectively experienced adverse drug reactions such as anorexia, nausea and fatigue were related to depression mood disorder level. In conclusion, psychological support and intervention should be provided to cancer patients in order to improve patient adherence and cancer chemotherapy effectiveness, and to decrease the incidence of adverse drug reactions.

The role of lipid peroxidation products and oxidative stress in activation of the canonical wingless-type MMTV integration site (WNT) pathway in a rat model of diabetic retinopathy

AIMS/HYPOTHESIS

Our recent studies suggest that activation of the wingless-type MMTV integration site (WNT) pathway plays pathogenic roles in diabetic retinopathy and age-related macular degeneration. Here we investigated the causative role of oxidative stress in retinal WNT pathway activation in an experimental model of diabetes.

METHODS

Cultured retinal pigment epithelial cells and retinal capillary endothelial cells were treated with a lipid peroxidation product, 4-hydroxynonenal (HNE), and an antioxidant, N-acetyl-cysteine (NAC). In vivo, rats with streptozotocin-induced diabetes were treated by NAC for 8 weeks. Activation of the canonical WNT pathway was measured by TOPFLASH assay and by western blot analysis of WNT pathway components and a WNT target gene, Ctgf. Oxidative stress in the retina was evaluated by immunostaining of HNE and 3-nitrotyrosine.

RESULTS

Levels of phosphorylated and total LDL receptor-related protein (LRP)6, and cytosolic β-catenin, as well as transcriptional activity of T cell factor (TCF)/β-catenin were significantly increased by HNE. The production of connective tissue growth factor (CTGF) was also upregulated by HNE. NAC blocked the WNT pathway activation induced by HNE. Furthermore, LRP6 stability was increased by HNE and decreased by NAC. Retinal levels of HNE and 3-nitrotyrosine were significantly increased in diabetic rats, compared with those in non-diabetic rats. In the same diabetic rat retinas, levels of LRP6, cytosolic β-catenin and CTGF were significantly increased. NAC treatment reduced HNE and 3-nitrotyrosine levels and attenuated the upregulation of LRP6, β-catenin and CTGF in diabetic rat retina.

CONCLUSIONS/INTERPRETATION

Lipid peroxidation products activate the canonical WNT pathway through oxidative stress, which plays an important role in the development of retinal diseases.

Microbial strategies to control aflatoxins in food and feed

Aflatoxins are a group of toxic and carcinogenic fungal metabolites. They are commonly found in cereals, nuts and animal feeds and create a significant threat to the food industry and animal production. Several strategies have been developed to avoid or reduce harmful effects of aflatoxins since the 1960s. However, prevention of aflatoxin contamination pre/post harvest or during storage has not been satisfactory and control strategies such as physical removing and chemical inactivating used in food commodities have their deficiencies, which limit their large scale application. It is expected that progress in the control of aflatoxin contamination will depend on the introduction of technologies for specific, efficient and environmentally sound detoxification. The utilisation of biological detoxification agents, such as microorganisms and/or their enzymatic products to detoxify aflatoxins in contaminated food and feed can be a choice of such technology. To date, many of the microbial strategies have only showed reduced concentration of aflatoxins and the structure and toxicity of the detoxified products are unclear. More attention should be paid to the detoxification reactions, the structure of biotransformed products and the enzymes responsible for the detoxification. In this article, microbial strategies for aflatoxin control such as microbial binding and microbial biotransformation are reviewed.

Optimal control for probabilistic Boolean networks

Aberrant gene functions usually contribute to the pathology or diseases. Avoiding undesirable cellular phenotypes as many as possible is a major purpose of external control for gene regulatory networks. An interesting question is how to control a gene network subjected to the condition that the genes reach some undesirable states with minimal probability during a cell cycle. In this paper, we make use of the theory of the first passage model for discrete-time Markov decision processes to determine the optimal control for a gene intervention model. Specifically, we first use a control model for a probabilistic Boolean network to model interactions among genes and then solve an optimal control problem for maximising the probability of the first arrival time to desirable gene states. In order to illustrate the validity of our approach, examples are also displayed.

Expression of survivin, caspase-3 and p53 in cervical cancer assessed by tissue microarray: correlation with clinicopathology and prognosis

OBJECTIVE

The aim of this study was to determine the role of survivin, caspase-3 and p53 expression in cervical cancer, and their correlation with clinicopathological features and prognosis.

METHODS

Two hundred and twenty-eight cases of cervical disease were analyzed retrospectively between February 2003 and May 2007 at Taizhou Hospital of Taizhou Enze Medical Center. The expressions of survivin, caspase-3 and p53 were detected by immunohistochemistry (EnVision), assessed by tissue microarray. The correlation of the three genes and clinicopathological factors as well as prognosis were statistically analyzed.

RESULTS

The results showed that the positive expression rate of survivin, caspase-3 and p53 in cervical cancer was significantly higher than in the CIN group and cervicitis group (p < 0.05). The expression of survivin was related with clinical staging, stromal involvement and lymph node metastasis (p < 0.05). The positive ratio of caspase-3 was significantly different from histological grading (p < 0.05). The positive expression of p53 was correlated with histological type and grading (p < 0.05). The expression of survivin in cervical cancer was negatively associated with that of caspase-3 (p < 0.01). The positive expression of survivin in the survival group and non-survival group was significantly statistically difference (p < 0.01). There was a significant difference between survivin expression and survival duration by the log-rank method. Whereas no association with survival was seen for caspase-3 and p53 positivity.

CONCLUSION

Survivin, caspase-3 and p53 may play an important role in the occurrence and development of cervix carcinoma. It has been suggested that the high expression of survivin or p53 and low expression of caspase-3 are closely correlated with cervical cancer. They could be used as markers for malignant degree and invasiveness of cervix cancer. Survivin can also be used in the estimation of prognosis and survival time of cervix carcinoma.

Inhibitory role of toll-like receptors agonists in Plasmodium yoelii liver stage development

It is well known that innate immune plays an important role in controlling the development of Plasmodium liver stage. However, little is known about the role of toll-like receptors (TLR) signalling in the pre-erythrocytic immunity against Plasmodium. Here, we found that pre-treatment with individual TLR agonist pam3CSK4 (TLR2), poly(I:C) (TLR3), LPS (TLR4) and CpG (TLR9) could decrease significantly the liver malaria parasite load in mice for 58%, 63%, 75% and 88% respectively. Moreover, no parasitaemia was observed within 14 days in CpG group mice challenged with 100 sporozoites. At 24 h prior to CpG injection, administration of gadolinium chloride (GdCl(3)) led to the rebound of liver Plasmodium load through inhibiting selectively Kupffer cells (KC) phagocytosis capacity but failed to neutralize completely CpG-induced immunity against malaria liver stage. Compared with the control, pre-treatment of CpG up-regulated hepatic pro-inflammatory cytokines IL-12, IFN-gamma and TNF-alpha, but down-regulated anti-inflammatory cytokines IL-10 and TGF-beta. Hence, our data demonstrated the inhibitory role of diverse TLR agonists in the Plasmodium development during pre-erythrocytic stage. As the most robust agonist, CpG might inhibit the development of Plasmodium liver stage through regulation of intrahepatic inflammatory cytokines and enhancement of KC cells phagocytosis capacity.