Effect of exogenous CdS nanoparticle on the growth of Escherichia coli / 生物工程学报

Semiconductor nanoparticles generate photoelectrons and photo-induced holes under light excitation, and thus may influence the growth of microbial cells. The highly oxidative holes may severely damage the cells, while the photoelectrons may promote microbial metabolism. In this study, we evaluated the effect of exogenous cadmium sulfide (CdS) nanoparticles on bacterial growth using OD600 and colony forming unit (CFU) as indicators. The oxidase activities, the concentration of pyruvate and malondialdehyde, and the expression of relevant genes assessed by real-time fluorescent quantitative PCR were analyzed to investigate the effect of excited CdS on cellular metabolism. The results showed that the OD600 and pyruvate accumulation of E. coli increased by 32.4% and 34.6%, respectively, under light conditions. Moreover, the relative expression level of the division protein gene ftsZ was increased more than 50%, and the tricarboxylic acid cycle pathway gene icdA and gltA increased by 86% and 103%, respectively. The results indicated that photoelectrons could be used by microorganisms, resulting in promoted growth and metabolism. This study gives a deep insight into the interaction between nanoparticles and bacteria.

Guía de práctica clínica para el diagnóstico y tratamiento de la intoxicación por cadmio / Clinical practice guideline for the diagnosis and treatment of cadmium poisoning

La presente publicación describe los criterios técnicos para la prevención, diagnóstico, tratamiento de la intoxicación por Cadmio, así como de las potenciales secuelas en personas expuestas a fuentes de contaminación con este metal

Development of sandwich-form biosensor to detect Mycobacterium tuberculosis complex in clinical sputum specimens

Mycobacterium tuberculosis, the causing agent of tuberculosis, comes second only after HIV on the list of infectious agents slaughtering many worldwide. Due to the limitations behind the conventional detection methods, it is therefore critical to develop new sensitive sensing systems capable of quick detection of the infectious agent. In the present study, the surface modified cadmium-telluride quantum dots and gold nanoparticles conjunct with two specific oligonucleotides against early secretory antigenic target 6 were used to develop a sandwich-form fluorescence resonance energy transfer-based biosensor to detect M. tuberculosis complex and differentiate M. tuberculosis and M. bovis Bacille Calmette–Guerin simultaneously. The sensitivity and specificity of the newly developed biosensor were 94.2% and 86.6%, respectively, while the sensitivity and specificity of polymerase chain reaction and nested polymerase chain reaction were considerably lower, 74.2%, 73.3% and 82.8%, 80%, respectively. The detection limits of the sandwich-form fluorescence resonance energy transfer-based biosensor were far lower (10 fg) than those of the polymerase chain reaction and nested polymerase chain reaction (100 fg). Although the cost of the developed nanobiosensor was slightly higher than those of the polymerase chain reaction-based techniques, its unique advantages in terms of turnaround time, higher sensitivity and specificity, as well as a 10-fold lower detection limit would clearly recommend this test as a more appropriate and cost-effective tool for large scale operations.

Effects of nanosized cadmium sulfide on male reproductive system in mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of nanosized cadmium sulfide (nano-CdS) on the male reproductive system in mice.</p><p><b>METHODS</b>Thirty-six specific pathogen?free male ICR mice were equally and randomly divided into three groups: two experimental groups and a control group. The two experimental groups were exposed to 100 mg/kg and 50 mg/kg nano-CdS once daily by gavage, respectively, while the control group was exposed to the same volume of physiological saline once daily by gavage. After 45 days, levels of cadmium accumulation and serum testosterone in the testis were determined, the epididymal sperm count, the rate of sperm abnormality, and histopathological changes in testis tissue were observed under a microscope, and the level of CYP11A1 mRNA was determined by qRT-PCR.</p><p><b>RESULTS</b>Compared with the control group, the two experimental groups had a significantly increased level of cadmium accumulation in the testis (P < 0.05), and the 100 mg/kg nano-CdS group had a significantly decreased epididymal sperm count (P < 0.05) and a significantly increased rate of sperm abnormality (P < 0.05), but the 50 mg/kg nano-CdS group did not. The 100 mg/kg nano-CdS group showed different histopathological changes in testis tissue, but the 50 mg/kg nano-CdS group did not. The two experimental groups had significantly reduced levels of testosterone and CYP11A1 mRNA compared with the control group.</p><p><b>CONCLUSION</b>Nano-CdS given through the digestive tract may have an effect on the male reproductive system in mice by affecting the key enzyme genes in the androgen synthesis pathway to reduce the levels of reproductive hormones.</p>

Preparation and characterization of tumor targeted CdTe quantum dots modified with functional polymer / 药学学报

N-acetyl-L-cysteine (NAC) capped quantum dots (QDs) were synthesized by a hydrothermal method and coated with 2-amino-2-deoxy-D-glucose (DG), polyethylene glycol (PEG), and 9-D-arginine (9R). The optical properties, morphology and structure of 9R/DG-coated CdTe QDs were characterized by ultraviolet-visible spectrometry, fluorescence spectrum, Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), liquid chromatography-mass spectrometer (LC-MS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transmission electron micrographs (TEM). Furthermore, the biocompatibility, tumor targeted ability and transmembrane action of 9R/DG-coated CdTe QDs were studied. Results indicated that 9R/DG-coated CdTe QDs was constructed successfully by ligand exchange. The 9R/DG-coated CdTe QDs with the size of 8-10 nm had good dispersity and the absorbance and fluorescence peaks of CdTe QDs after modification were red shifted from 480 nm to 510 nm and 627 nm to 659 nm, respectively. In addition, the CdTe QDs modified by PEG, DG and 9R displayed good biocompatibility, high targeted ability to the cancer cells with glucose transporter type 1 (GLUT1) receptor high expression and obvious transmembrane ability.

vivo effects of quantum dot on organs development before maturity

The field of nanotechnology is rapidly expanding .The development quantum dots quantum dot [QDs], show great promise for treatment and diagnosis of cancer and targeted drug delivery little data on the toxicity of QDs, especially for in vivo applications, are available. As a result, concerns exist over their toxicity for in vivo applications. Then, cytotoxic effects of cadmium selenide [CdSe] quantum dots on organs development before maturity were studied in this study. One month old male Mice treated by injection of CdSe at the doses of 10, 20 and 40 mg/kg. Structural and optical properties of quantum dots were studied by XRD, UV-Vis absorption spectrum and Scanning Tunneling Microscopy and the number of cells in seminiferous tubes of various groups were analyzed using SPSS 16 program [one way ANOVA test]. Histological studies of testis tissue showed high toxicity of cdse in the dose of 40 mg/kg which followed by decrease in lamina propria thickness, destruction in interstitial tissue, deformation of seminiferoustubes, and reduction in number cells. Also histological study of lung tissue showed in 20 and 40 mg/kg doses destruction in interstitial and epithelium tissues. On the whole, this study showed high toxicity of cdse on development of testis and lung tissues, even in low doses considering lack of literature review in this field, this study can be an introduction to researches about toxicity effect of quantum dots on development of organs

Synthesis and bioactivity of the folate receptor targeted gamma-cyclodextrin-folate inclusion-coated CdSe/ZnS quantum dots / 药学学报

The gamma-cyclodextrin-folate (gamma-CD/FA) inclusion-coated CdSe/ZnS quantum dots (QDs) with folate-receptor (FR) targeted were synthesized by simple and convenient sonochemical method. The products were studied using Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), utraviolet-visible spectrometry (UV-vis), fluorescence spectrum and transmission electron micrographs (TEM). The results showed that the gamma-CD/FA-coated CdSe/ZnS QDs not only have good monodispersity and smaller size, but also have good optical performance, such as higher quantum yield (QY) and a long fluorescence lifetime. The cytotoxicity experiments showed that the gamma-CD/FA-coated CdSe/ZnS QDs have lower cytotoxicity and could more effectively enter cancer cells with FR over-expression. The QDs with 4-5 nm in diameter were relatively easy to enter the cell and to be removed through kidneys, so it is more suitable for biomedical applications for bioprobes and bioimaging.

Studying nanotoxic effects of CdTe quantum dots in Trypanosoma cruzi

Semiconductor nanoparticles, such as quantum dots (QDs), were used to carry out experiments in vivo and ex vivo with Trypanosoma cruzi. However, questions have been raised regarding the nanotoxicity of QDs in living cells, microorganisms, tissues and whole animals. The objective of this paper was to conduct a QD nanotoxicity study on living T. cruzi protozoa using analytical methods. This was accomplished using in vitro experiments to test the interference of the QDs on parasite development, morphology and viability. Our results show that after 72 h, a 200 μM cadmium telluride (CdTe) QD solution induced important morphological alterations in T. cruzi, such as DNA damage, plasma membrane blebbing and mitochondrial swelling. Flow cytometry assays showed no damage to the plasma membrane when incubated with 200 μM CdTe QDs for up to 72 h (propidium iodide cells), giving no evidence of classical necrosis. Parasites incubated with 2 μM CdTe QDs still proliferated after seven days. In summary, a low concentration of CdTe QDs (2 μM) is optimal for bioimaging, whereas a high concentration (200 μM CdTe) could be toxic to cells. Taken together, our data indicate that 2 μM QD can be used for the successful long-term study of the parasite-vector interaction in real time.

Optimization of bacteriological quality of biosolids by lime addition

Lack of well-stabilized biosolids is a basic problem for many municipal wastewater treatment plants in Iran. Disposed biosolids from west Ahvaz wastewater treatment plant were generally used for agricultural activities. Initial evidence showed that these biosolids were untreated and had the potential to transmit many pollutants to the environment and create hazards for public health, although anaerobic digester was selected for this wastewater treatment plant. The main objective of this research was to evaluate and optimize the bacteriological quality of biosolids by lime addition in west Ahvaz wastewater treatment plant. The stability and reuse potential of biosolids from existing anaerobic digester and lime added biosolids were investigated. Lime addition to biosolids was performed in the reactor with 30 L capacity. Averge amounts of fecal coliforms and viable helminthes ova in disposal biosolids from anaerobic digester were 1.3'1015 MPN / g of dry solids and 314 ova / 4 g of dry solids, respectively. By lime addition with the ratio about 0.265 g Ca [OH]2 per g of dry solids, pH was not dropped under 12 and growth of fecal coliform was not detected after 30 days. In this regard, discharged biosolids from this plant was unstable and very dangerous for reuse or disposal. Lime addition could stabilize the biosolids and reduce fecal coliforms more than 99.99% and had concordance with class B of United State Environmental Protection Agency criteria. Lime-stabilized biosolids could hence be well used for reconditioning the poor soil and for covering of solid waste landfill-sites

Apical barrier therapies in traumatized immature teeth - a case report

This case report reviews the rationale and techniques for treatment of non vital immature tooth. The importance of careful case assessment through clinical examination and investigation, and accurate pulpal diagnosis in the treatment of immature teeth with pulpal injury cannot be overemphasized. The treatment of choice for necrotic teeth is apexification, which is induction of apical closure to produce more favourable conditions for conventional root canal filling. The most commonly adovacated medicament is calcium hydroxide, although recently considerable interest has been expressed in the use of mineral trioxide aggregate

On-chip magnetic separation of microcantilever immunosensor based on the CdSe QDs-tagged magnetic microbead / 生物工程学报

We designed a novel microcantilever immuosensor based on magnetic microbead, applying different-sized CdSe QDs as fluorescent probes and polystyrene magnetic microbead. The novel microcantilever immuosensor used fluorescent probes embedded polystyrene microbeads and specific antibodies on the surface of the polystyrene microbead. In addition, we studied the mechanism of the on-chip magnetic separation, the structure of micro-electromagnet and the microbead magnetization by the micro-magnetic field, the snake-shaped planar micro-electromagnet for the novel microcantilever immuosensor.

Assessment of Occupational Exposure to Cadmium in Korea / 대한산업의학회지

Twenty-four factories registered at the Ministry of Labor as factories using or producing cadmium in 1991 were investigated to know the present state of occupational exposure to cadmium in 1992. Nine factories among 24 stopped using or changed to other substances and 1 factory didn't produce any more, but delivered it to other factories through imports. Therefore, only 14 factories were producing or using cadmium. But, alloying materials were uspplied to about 20 and more factories, however, they couldn't be investigated because of limited information. Three factories had less than 50 workers were 3, 6 had 50-300 and 5 had more than 300. About 167 workers were exposed to cadmium. According to the classification by process, there were 4 alloy processes, 2 refinary, 2 elctroplating, 2 dry cell making, 1 industrial battery and 1 copper refinary. 8 factories used metal cadmium, 3 cadmium oxide, 2 cadmium sulfide, and 1 cadmium hyroxide. One factory was importing cadmium stearates only and supplying them to the PVC making factories. The amount of metal cadmium producing in 2 refinary factories was about 50-65 ton per month. The other cadmium compounds were imported. According to exposure level of cadmium in air of the 10 factories examined, each factory could be divided into high, moderate and low exposure groups. 1 battery recycling factory and 3 alloy factories were in the high exposure group and their mean air concentrations were 0.06679, 0.05481, 0.02492, and 0.003mg/m3, respectively. Refinary and industrial battery making factories were in the middle exposure group and their mean air concentrations were 0.00773 and 0.00613 mg/m3, respectively. Finally, low exposure group were copper smelting, dry cell case making, duplicator drum making and electroplating factory and their mean air concentrations were 0.00096, 0.00071, 0.00057 and 0.00054 mg/m3 respectively.

Metal uptake by mycelia during submerged growth and by sporocarps of an edible fungus Volvariella volvacea.

Uptake of a few metals by V. volvacea was determined during submerged growth of the organism in sublethal concentration of each metal salt. The uptake of Pb2+ and Hg2+ was 5 and 5.23 micrograms g-1 respectively while that of Cu2+ was 500 micrograms g-1 under experimental conditions. Treatment of spawned substrate separately with different metal salts showed maximum and minimum uptake of Pb2+ (100 micrograms g-1) and Cd2+ (2.93 micrograms g-1) respectively by sporocarps. All metal salts at test concentrations reduced biological efficiency of sporocarp production but markedly by Co2+. Cd2+ and Co2+ were highly toxic to mycelia and sporocarps respectively. The uptake of Cu2+ by mycelia and Pb2+ by sporocarps were highest among the five metals tested. Metal toxicity, tolerance and uptake capacity of V. volvacea differ considerably with concentration of metal ions.