Toll-like receptor-4-dependence of the lipopolysaccharide-mediated inhibition of osteoblast differentiation.

Bone fractures or bones subjected to open conduction and internal fixation are easily infected by bacteria; bacterial lipopolysaccharide (LPS) has been recognized as an important pathogenic factor affecting bone fracture healing. Therefore, the effect of LPS on bone metabolism is relevant for bone healing. In this study, we investigated the effect of LPS on the expression of Toll-like receptor (TLR)-4 (an LPS receptor) by using real-time quantitative PCR and western blotting. We also examined the regulatory role of LPS in osteoblast differentiation by measuring the ALP activity, matrix mineralization, and ALP, OCN, and Runx2 mRNA (essential factors affecting osteoblast differentiation) expression in LPS-treated mouse osteoblast MC3T3-E1 cells. We also evaluated the effect of TLR-4 on LPS-mediated inhibition of osteoblast differentiation using RNA interference. LPS promotes TLR-4 mRNA and protein expression in MC3T3-E1 cells (P < 0.05, P < 0.01 or P < 0.001), and inhibits osteoblast differentiation by downregulating matrix mineralization and ALP activity (P < 0.05, P < 0.01 or P < 0.001), and suppressing the expression ALP, OCN, and Runx2 mRNA in MC3T3-E1 cells (P < 0.05 or P < 0.01). Conversely, RNAi-mediated TLR-4 knockdown abrogates the LPS-mediated inhibition of osteoblast differentiation (P < 0.05 or P < 0.01). In summary, LPS was shown to inhibit osteoblast differentiation by suppressing the expression of ALP, OCN, and Runx2 in a TLR-4-dependent manner. The results of this study may provide insights into the signal pathway of LPS-induced bone loss or delayed bone fracture healing.

Colonic pressure data processing based on independent component analysis.

The Colonic manometry is an important technique to evaluate human colonic motor functions, which are critical for doctors to understand the pathology of intestinal diseases like slow transit constipation (STC) and colonic inertia (CI). However, in the obtained pressure signals, several patterns of colonic motor activities as well as noises mixed together, which made it difficult to observe the information people really needed. In this article, a new method was proposed to extract patterns of colonic motility from the mixed signals, so that researchers could study them thoroughly. Colonic pressure recordings from 26 volunteers were obtained by the water-perfused manometry catheters. Then independent component analysis (ICA) was introduced, which successfully separated colonic motility patterns and noises into four independent components. And according to the rhythm of contractions examined by ICA, subjects' colonic motility could be divided into three types: regular rhythm (12 subjects), slow rhythm (8 subjects) and disordered (6 subjects), which exactly accorded with their original diagnosis.

Reducing oxidative stress in sweet cherry fruit by Pichia membranaefaciens: a possible mode of action against Penicillium expansum.

AIMS: To investigate the effect of antagonistic yeast Pichia membranaefaciens on alleviating oxidative stress caused by Penicillium expansum in sweet cherry fruit. METHODS AND RESULTS: At two maturity stages of sweet cherry fruit, P. membranaefaciens restrained blue mold rot caused by Pe. expansum. There was not any decay in yeast-treated fruit even at 5 days after inoculation. Carbonylated proteins accumulated to a lesser extent in yeast-treated fruit than in control fruit, particularly in non-full-matured stage fruit. Higher activities of catalase (CAT) and glutathione peroxidase (GPX) were observed in yeast-treated fruit, which consisted of the transcript expressions of CAT and GPX genes. In addition, yeast treatment also stimulated the transcript expression of Gns1 and activity of beta-1,3-glucanase. CONCLUSION: Induction of antioxidant defence response may be an important mechanism of antagonistic yeast in mitigating pathogen-induced oxidative stress to postharvest fruit and controlling postharvest disease. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study showed a potential mode of action of antagonistic yeast in postharvest fruit disease control, which may be an important development in the understanding of antagonists in postharvest biocontrol and may provide important guidance for their application in the future.

Effect of intracellular trehalose in Cryptococcus laurentii and exogenous lyoprotectants on its viability and biocontrol efficacy on Penicillium expansum in apple fruit.

AIMS: To improve viability and biocontrol efficacy of Cryptococcus laurentii after freeze drying and in subsequent storage. METHODS AND RESULTS: Viability of C. laurentii was improved after freeze drying and in subsequent storage at 4 or 25 degrees C by using skimmed milk (SM) and sugars (glucose, galactose, sucrose and trehalose) as protectants. Sugars and SM mixed together showed better protection than when they were used separately. Citric acid used as carbon source could induce accumulation of intracellular trehalose in the yeast. The yeast cells with high trehalose level (HT cells) had higher viability than those with low trehalose level (LT cells) after freeze drying and storage for 90 days. After storage for 90 days at 4 degrees C, the HT cells plus SM and sugars as protectant showed a similar biocontrol effect against blue mould rot in apple fruit caused by Penicillium expansum as fresh cells. CONCLUSIONS: Increasing intracellular trehalose content of C. laurentii and adding exogenous protectant (sugars + SM) could improve its viability and maintain its biocontrol efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: The results have a potential value for commercial application of C. laurentii.

Effects of trehalose on stress tolerance and biocontrol efficacy of Cryptococcus laurentii.

AIMS: To investigate the effects of internal trehalose on viability and biocontrol efficacy of antagonistic yeast Cryptococcus laurentii under stresses of low temperature (LT), controlled atmosphere (CA) and freeze drying. METHODS AND RESULTS: The content of trehalose in C. laurentii was increased by culturing the yeast in trehalose-containing medium. Compared with yeast cells with low trehalose level, the yeast cells with high level of internal trehalose not only obtained higher viability, but also showed higher population and better biocontrol efficacy against Penicillium expansum on apple fruit both at 1 degrees C and in CA condition (5% O(2), 5% CO(2), 1 degrees C). After freeze drying, survival of the yeast with high trehalose level was markedly increased when stored at 25 degrees C for 0, 15 and 30 days. Meanwhile, high integrity of plasma membrane was detected in the freeze-dried yeast with high trehalose level by propidium iodide staining. CONCLUSIONS: Induced accumulation of internal trehalose could improve viability and biocontrol efficacy of C. laurentii under stresses of LT and CA. Moreover, survival of the yeast was also increased as internal trehalose accumulation after freeze drying, and one of the reasons might be that trehalose gave an effective protection to plasma membrane. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this experiment show a promising way to improve the biocontrol performance of antagonistic yeasts under the commercial conditions.

Combination of antagonistic yeasts with two food additives for control of brown rot caused by Monilinia fructicola on sweet cherry fruit.

AIMS: To evaluate beneficial effect of two food additives, ammonium molybdate (NH4-Mo) and sodium bicarbonate (NaBi), on antagonistic yeasts for control of brown rot caused by Monilinia fructicola in sweet cherry fruit under various storage conditions. The mechanisms of action by which food additives enhance the efficacy of antagonistic yeasts were also evaluated. METHODS AND RESULTS: Biocontrol activity of Pichia membranefaciens and Cryptococcus laurentii against brown rot in sweet cherry fruit was improved by addition of 5 mmol l(-1) NH4-Mo or 2% NaBi when stored in air at 20 and 0 degrees C, and in controlled atmosphere (CA) storage with 10% O2 + 10% CO2 at 0 degrees C. Population dynamics of P. membranefaciens in the wounds of fruit were inhibited by NH4-Mo at 20 degrees C after 1 day of incubation and growth of C. laurentii was inhibited by NH4-Mo at 0 degrees C in CA storage after 60 days. In contrast, NaBi did not significantly influence growth of the two yeasts in fruit wounds under various storage conditions except that the growth of P. membranefaciens was stimulated after storage for 45 days at 0 degrees C in CA storage. When used alone, the two additives showed effective control of brown rot in sweet cherry fruit and the efficacy was closely correlated with the concentrations used. The result of in vitro indicated that growth of M. fructicola was significantly inhibited by NH4-Mo and NaBi. CONCLUSION: Application of additives improved biocontrol of brown rot on sweet cherry fruit under various storage conditions. It is postulated that the enhancement of disease control is directly because of the inhibitory effects of additives on pathogen growth, and indirectly because of the relatively little influence of additives on the growth of antagonistic yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained in this study suggest that an integration of NH4-Mo or NaBi with biocontrol agents has great potential in commercial management of postharvest diseases of fruit.

Sodium Silicate Reduces Postharvest Decay on Hami Melons: Induced Resistance and Fungistatic Effects.

The effect of sodium silicate (Si) for control of decay was tested in Hami melons (Cucumis melo L. var. inodorus Jacq.). Si significantly inhibited mycelial growth of Alternaria alternata, Fusarium semitectum, and Trichothecium roseum in vitro. Si at 100 mM was more effective than Si at 25 or 50 mM at controlling the diseases caused by the three pathogens, whereas Si at 200 mM was phytotoxic. Si treatments applied at 100 mM pre-inoculation with T. roseum had lower decay incidence and severity than treatments applied post-inoculation. The protection of Si was correlated with the activation of two families of defense-related enzymes, peroxidase and chitinase. Accumulation of both enzymes was induced in fruit treated with Si and challenged by T. roseum 24 h later, and was sustained for at least 9 days in 'New Queen' and 10 days in '8601' at room temperature. It appeared that induced resistance was an important mechanism of disease control in Hami melons treated with Si.

Effects of a biocontrol agent and methyl jasmonate on postharvest diseases of peach fruit and the possible mechanisms involved.

AIMS: To investigate effects of application of 200 micromol l(-1) methyl jasmonate [MeJA (200)] and Cryptococcus laurentii alone or in combination against postharvest diseases (Monilinia fructicola and Penicillium expansum) in peach fruit stored at 25 and 0 degrees C, and to evaluate the possible mechanisms involved. METHODS AND RESULTS: The efficacy of controlling postharvest diseases by resistance induced in peach fruit treated with MeJA (200) and C. laurentii alone or in combination and the relationship between activities of defence-related enzymes in peach fruit and lesions caused by M. fructicola and P. expansum were examined. At the same time, the effects of MeJA (200) on the population of C. laurentii in the peach wounds and on the mycelial growth of M. fructicola and P. expansumin vitro were investigated. The results indicated that treatment of peach fruit with C. laurentii at 1 x 10(8) CFU ml(-1) alone, or combining C. laurentii at 5 x 10(7) CFU ml(-1) with MeJA (200) all resulted in a lower lesion diameter of brown rot and blue mould caused by M. fructicola and P. expansum compared with the controls in peach fruit. MeJA (200) enhanced the population of C. laurentii, and inhibited mycelial growth of P. expansum. However, it had a little effect on M. fructicolain vitro. MeJA and C. laurentii alone or in combination induced higher activities of Chitinase, beta-1,3-glucanase, phenylalanine ammonia-lyase and peroxidase (POD) than applying the yeast alone at both 25 and 0 degrees C. CONCLUSIONS: MeJA (200) not only directly inhibited mycelial spread of postharvest pathogens, but also increased population of C. laurentii, which induced stronger disease resistance in fruit than MeJA or yeast alone, and resulted in a lower lesion diameter of brown rot and blue mould caused by M. fructicola and P. expansum. SIGNIFICANCE AND IMPACT OF THE STUDY: MeJA (200) in combination with C. laurentii was beneficial for controlling brown rot and blue mould caused by M. fructicola and P. expansum in peach fruit. The inhibitory mechanism was mainly because of resistance induced in peach fruit by MeJA and C. laurentii. In addition, direct inhibition of MeJA on P. expansum also played a role in controlling blue mould.

Enhancement of biocontrol activity of yeasts by adding sodium bicarbonate or ammonium molybdate to control postharvest disease of jujube fruits.

AIMS: To assess the potential of sodium bicarbonate and ammonium molybdate as additives in enhancing the biocontrol efficacy of Rhodotorula glutinis and Cryptococcus laurentii against blue mould in jujube fruits. METHODS AND RESULTS: Two yeasts at a concentration of 107 CFU ml-1, in combination with 238 mmol l-1 sodium bicarbonate or 15 mmol l-1 ammonium molybdate, showed a significant inhibition effect on blue mould of jujube fruits stored at 20 degrees C for 5 days. The colonizing ability of the yeasts in wounded sites was significantly decreased in the presence of ammonium molybdate. CONCLUSIONS: Combining R. glutinis or C. laurentii with sodium bicarbonate or ammonium molybdate provided a more effective control of postharvest disease than using the antagonistic yeasts or the chemicals alone. SIGNIFICANCE AND IMPACT OF THE STUDY: The addition of sodium bicarbonate or ammonium molybdate reduced the number of antagonists required to efficiently control disease of postharvest fruits, which could result in the reduction of costs.

[Effects of gastric mucosal blood flow (GMBF) on the role of adaptive cytoprotection of rat gastric mucosa].

By the use of hydrogen gas clearance technique, we have investigated the role of GMBF in the adaptive cytoprotection induced by intragastric perfusion with low concentration prior to high concentration of HCl plus ethanol. The results were as follows: (1) intragastric perfusion with low concentration prior to high concentration of HCl plus ethanol led to an adaptive cytoprotection, i.e., the gross and the deep damage were decreased by 47.09% and 44.57% respectively, as compared with those caused by high concentration of HCl plus ethanol alone; correspondingly, GMBF also showed an adaptive hyperemic response, i.e., GMBF was increased by 28.02% as compared with that due to high concentration alone; (2) close arterial infusion of vasopressin blocked the adaptive hyperemic response and abolished the adaptive cytoprotection; (3) intravenous indomethacin reduced the basal GMBF, and abolished both the adaptive hyperemic response and cytoprotection; furthermore, the gross and deep damage were aggravated compared with that caused by high concentration alone. The results showed that the adaptive hyperemic response of gastric mucosa was involved in the adaptive cytoprotection and suggested that the adaptive cytoprotection of endogenous prostaglandin might be partially related to the increase of GMBF.

[Capsaicin-sensitive afferent neurons and endogenous nitric oxide (NO) mediate the gastric acid secretion and hyperemic responses to intragastric peptone].

Using hydrogen gas clearance technique to measure gastric mucosal blood flow (GMBF) and a high dose of capsaicin to ablate the capsaicin-sensitive afferent neurons, the role of capsaicin-sensitive neurons in the gastric acid secretion and hyperemic response to intragastric peptone was investigated. The results were as follows: (1) there was an increase in acid secretion associated with the hyperemic response to intragastric peptone; (2) pretreatment with a high dose of capsaicin to ablate afferent neurons completely abolished the gastric hyperemic response to intragastric peptone and partially inhibited the acid secretion; (3) the gastric hyperemic response to intragastric peptone was completely blocked by pretreatment with L-nitro-arginine methyl ester (L-NAME), whereas the acid secretion was significantly attenuated; (4) inhibited effects of L-NAME on acid secretion and GMBF could be reversed by pretreatment with L-arginine (L-ARG); (5) pretreatment with atropine inhibited gastric acid output (GAO) and partially attenuated GMBF. These results suggested that capsaicin-sensitive afferent neurons and endogenous NO were involved in the gastric acid secretion and hyperemic response to intragastric peptone and the hyperemic response was mediated by both cholinergic and noncholinergic neurons.

[A study on Mechanism of prevention and treatment of gastric ulcer with Os sepiella in rats].

The Os Sepiella maiudrone (OSM) could markedly inhibit the stress-induced gastric mucosal lesions and promote the healing of acetic acid-induced gastric ulcer in rats were reported previously. In order to demonstrate its mechanism, the effects of OSM on acidity of gastric juice, combined mucus content in gastric wall, DNA synthesis, gastric movements, the gastric contents of prostaglandin E2 (PGE2) and cAMP of gastric tissue were examined. The results showed that OSM could neutralize the gastric acid, promote the production of cAMP and PGE2 in gastric tissue. These suggested that the neutralization of gastric acid and enhancing the gastric mucosal cytoprotection by OSM would play a role in preventing and curing gastric ulcers in rats.