Search

Fecal microbial contamination in the food chain is a significant concern in the field of food safety as it is one of the most important pathways causing foodborne diseases. Microbial source tracking (MST) is an effective approach to address this issue, which can track the sources and contamination of fecal microbes. MST methods can be categorized into two types: library-dependent methods (LDMs) and library-independent methods (LIMs), with LIMs including culture-dependent and culture-independent methods. The non-culture-dependent method using 16S rRNA and host-microbial interaction genes as specific molecular markers has been widely used to investigate microbial contamination in the food chain. This review provides an overview of the basic principle and characteristics of MST, and focuses on recent advances in MST methods based on host-specific molecular markers for tracing microbial contamination in the food chain. Furthermore, future prospects of MST are discussed based on its unique advantages and disadvantages.

The effect of TiO2 nanoparticles with different physical characters on MC3T3-E1 cells proliferation, differentiation and immunotoxity has been investigated. The CCK-8 method shows that the anatase and rutile nano-TiO2 inhibit cells proliferation at the concentration of 20, 50, 100 µg/mL. The anatase nano-TiO2 shows more inhibitory effect on cells viability than rutile, but there is not statistically different. Coculturing with MC3T3-E1 for 7 d and 14 d, the anatese and rutile both decrease the alkaline phosphatase (ALP) synthesis. The enzyme-linked immunosorbent assay (ELISA) is used to detect the interleukin-1 (IL-1) and interleukin-6 (IL-6) levels in the cell cultures. By culturing by anatase and rutile at different concentration, MC3T3-E1 secretes IL-1, at the same time largely secretes IL-6. In addition, at the concentration of 20 µg/mL, the anatase stimulates cells to secrete more IL-6 than rutile. Therefore, TiO2 nanoparticles have an influence on the proliferation and differentiation of MC3T3-E1 cells and cause the immunotoxicity. [ABSTRACT FROM AUTHOR]

Abstract: Nanoscale titanium dioxide (TiO2) is massively produced and widely used in living environment, which hence make the potential risk to human health. Central nervous system (CNS) is the potential susceptible target of inhaled nanoparticles, but the studies on this aspect are limited so far. We report the accumulation and toxicity results in vivo of two crystalline phases of TiO2 nanoparticles (80nm, rutile and 155nm, anatase; purity >99%). The female mice were intranasally instilled with 500μg of TiO2 nanoparticles suspension every other day for 30 days. Synchrotron radiation X-ray fluorescence analysis (SRXRF) and inductively coupled plasma mass spectrometry (ICP–MS) were used to determine the contents of titanium in murine brain. Then, the pathological examination of brain tissue, oxidative stress-mediated responses, and levels of neurochemicals in the brain of exposed mice were also analyzed. The obvious morphological changes of hippocampal neurons and increased GFAP-positive astrocytes in the CA4 region were observed, which were in good agreements with higher Ti contents in the hippocampus region. Oxidative stress occurred obviously in whole brain of exposed mice such as lipid peroxidation, protein oxidation and increased activities of catalase, as well as the excessive release of glutamic acid and nitric oxide. These findings indicate anatase TiO2 nanoparticles exhibited higher concern on some tested biological effects. To summarize, results provided the preliminary evidence that nasal instilled TiO2 nanoparticles could be translocated into the central nervous system and cause potential lesion of brain, and the hippocampus would be the main target within brain. [Copyright &y& Elsevier]

Abstract: Nanoparticles can be administered via nasal, oral, intraocular, intratracheal (pulmonary toxicity), tail vein and other routes. Here, we focus on the time-dependent translocation and potential damage of TiO2 nanoparticles on central nervous system (CNS) through intranasal instillation. Size and structural properties are important to assess biological effects of TiO2 nanoparticles. In present study, female mice were intranasally instilled with two types of well-characterized TiO2 nanoparticles (i.e. 80nm, rutile and 155nm, anatase; purity>99%) every other day. Pure water instilled mice were served as controls. The brain tissues were collected and evaluated for accumulation and distribution of TiO2, histopathology, oxidative stress, and inflammatory markers at post-instillation time points of 2, 10, 20 and 30days. The titanium contents in the sub-brain regions including olfactory bulb, cerebral cortex, hippocampus, and cerebellum were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results indicated that the instilled TiO2 directly entered the brain through olfactory bulb in the whole exposure period, especially deposited in the hippocampus region. After exposure for 30days, the pathological changes were observed in the hippocampus and olfactory bulb using Nissl staining and transmission electron microscope. The oxidative damage expressed as lipid peroxidation increased significantly, in particular in the exposed group of anatase TiO2 particles at 30days postexposure. Exposure to anatase TiO2 particles also produced higher inflammation responses, in association with the significantly increased tumor necrosis factor alpha (TNF-α) and interleukin (IL-1β) levels. We conclude that subtle differences in responses to anatase TiO2 particles versus the rutile ones could be related to crystal structure. Thus, based on these results, rutile ultrafine-TiO2 particles are expected to have a little lower risk potential for producing adverse effects on central nervous system. Although understanding the mechanisms requires further investigation, the present results suggest that we should pay attention to potential risk of occupational exposure for large-scaled production of TiO2 nanoparticles. [Copyright &y& Elsevier]

Abstract: In order to evaluate the toxicity of TiO2 particles, the acute toxicity of nano-sized TiO2 particles (25 and 80nm) on adult mice was investigated compared with fine TiO2 particles (155nm). Due to the low toxicity, a fixed large dose of 5g/kg body weight of TiO2 suspensions was administrated by a single oral gavage according to the OECD procedure. In 2 weeks, TiO2 particles showed no obvious acute toxicity. However, the female mice showed high coefficients of liver in the nano-sized (25 and 80nm) groups. The changes of serum biochemical parameters (ALT/AST, LDH) and pathology (hydropic degeneration around the central vein and the spotty necrosis of hepatocytes) of liver indicated that the hepatic injury was induced after exposure to mass different-sized TiO2 particles. In addition, the nephrotoxicity like increased BUN level and pathology change of kidneys was also observed in the experimental groups. The significant change of serum LDH and alpha-HBDH in 25 and 80nm groups showed the myocardial damage compared with the control group. However, there are no abnormal pathology changes in the heart, lung, testicle (ovary), and spleen tissues. Biodistribution experiment showed that TiO2 mainly retained in the liver, spleen, kidneys, and lung tissues, which indicated that TiO2 particles could be transported to other tissues and organs after uptake by gastrointestinal tract. [Copyright &y& Elsevier]

Abstract: Oxidative stress is considered to be one of the important mechanisms involved in carcinogenesis. In our previous study, gadolinium endohedral metallofullerenol ([Gd@C82(OH)22] n nanoparticles) have shown high inhibitory activity on hepatoma cell (H22) growth in mice. To explore the antioxidative functions of nanoparticles, we investigated the biodistribution of [Gd@C82(OH)22] n nanoparticles, the changes of blood coagulation profiles, the metabolism of reactive oxygen species (ROS) in the tumor-bearing mice as well as the possible relationships between nanoparticles treatment and ROS production in this paper. The activities of hepatic superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and catalase (CAT) as well as the levels of reduced glutathione (GSH), protein-bound thiols and malondialdehyde (MDA) were compared between the tumor-bearing mice and normal mice. Transplanted tumors were grown in mice by subcutaneous injection of murine hepatoma cells in the mice. The comparison of the above parameters between nanoparticles and cyclophosphamide (CTX) therapy were also investigated. [Gd@C82(OH)22] n administration can efficiently restore the damaged liver and kidney of the tumor-bearing mice. All the activities of enzymes and other parameters related to oxidative stress were reduced after [Gd@C82(OH)22] n treatment and tended closely to the normal levels. The results suggest that [Gd@C82(OH)22] n nanoparticle treatment could regulate ROS production in vivo. [Copyright &y& Elsevier]

Nanoscale titanium dioxide (TiO(2)) is massively produced and widely used in living environment, which hence make the potential risk to human health. Central nervous system (CNS) is the potential susceptible target of inhaled nanoparticles, but the studies on this aspect are limited so far. We report the accumulation and toxicity results in vivo of two crystalline phases of TiO(2) nanoparticles (80nm, rutile and 155nm, anatase; purity >99%). The female mice were intranasally instilled with 500microg of TiO(2) nanoparticles suspension every other day for 30 days. Synchrotron radiation X-ray fluorescence analysis (SRXRF) and inductively coupled plasma mass spectrometry (ICP-MS) were used to determine the contents of titanium in murine brain. Then, the pathological examination of brain tissue, oxidative stress-mediated responses, and levels of neurochemicals in the brain of exposed mice were also analyzed. The obvious morphological changes of hippocampal neurons and increased GFAP-positive astrocytes in the CA4 region were observed, which were in good agreements with higher Ti contents in the hippocampus region. Oxidative stress occurred obviously in whole brain of exposed mice such as lipid peroxidation, protein oxidation and increased activities of catalase, as well as the excessive release of glutamic acid and nitric oxide. These findings indicate anatase TiO(2) nanoparticles exhibited higher concern on some tested biological effects. To summarize, results provided the preliminary evidence that nasal instilled TiO(2) nanoparticles could be translocated into the central nervous system and cause potential lesion of brain, and the hippocampus would be the main target within brain.