A direct observation of bacterial coverage and biofilm formation by Acidithiobacillus ferrooxidans on chalcopyrite and pyrite surfaces.

To obtain a fundamental understanding of the population behaviour of Acidithiobacillus ferrooxidans at chalcopyrite and pyrite surfaces, the early stage attachment behaviour and biofilm formation by this bacterium on chalcopyrite (CuFeS2) and pyrite (FeS2) were studied by optical microscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and electron backscatter diffraction (EBSD). The results indicate there was no significant difference in selectivity of bacterial attachment between chalcopyrite and pyrite. However, the result of ToF-SIMS analysis suggests that the surface of the pyrite was covered more extensively by biofilm than that of the chalcopyrite, which may indicate more extracellular polymeric substances (EPS) formation by bacterial cells growing on pyrite. EBSD and optical image analysis indicated that selectivity of bacterial attachment to chalcopyrite was not significantly affected by crystal orientation. The results also suggest that the bacterial population in defective areas of chalcopyrite was significantly higher than on the polished surfaces.

Genetic affinities of central China populations.

Hunan locates in the south-central part of China, to the south of the middle reaches of the Yangtze River and south of Lake Dongting. According to the historical records, the peopling of Hunan by modern human ancestors can ascend to 40 thousand years ago. Thus, to trace the ancient maternal components can offer further insight into the origin of south-central China. In this study, we investigated the mitochondrial DNA of 114 individuals from Hunan Province (including 34 Han, 40 Tujia and 40 Miao). Hypervariable regions I and II of the mtDNA control region were sequenced, and the relative diagnostic variations in coding region according to the updated worldwide phylogeny tree were selected and typed by restriction fragment length polymorphism analysis or direct sequencing. All individuals were classified into specific (sub)haplogroups. By comparison with the surrounding populations, southern China-prevalent haplogroups were detected with relative higher frequency in the Tujia and Miao ethnic populations, such as haplogroup B, with more than 20%, lacking in the Han population, which illustrated its southern origin characters. In addition, we also detected northern of East Asia prevalent haplogroups with a relative higher frequency in Tujia populations than in the Miao and Yao ethnic groups, implying a gene flow from Han populations. However, the language-clustering tendency was supported by our principal component analysis and further genetic estimation results. Han and ethnic groups in central China exhibited specific ancestors related to their closer language affinity, although there was extensively genetic admixture between Han and ethnic groups.

Edible Bird Nest Protects the Kidney From Gentamicin Induced Acute Tubular Necrosis.

Every year, there are about 13.3 million cases of acute kidney injury (AKI). Although AKI is a preventable and treatable disease, if left untreated, it has high risk of multiple organ failure and progression to end stage kidney disease. Acute tubular necrosis (ATN) has been recognised as one of the major causes of AKI. Till to date, there is no effective supplement or medication in treating or reversing AKI. Most of the treatment strategies involve preventative measure to minimise the occurrence of AKI or to reverse the cause of AKI. Hence one of the primary area of research interests is to explore the potential treatment for AKI. Edible bird nests (EBN) are edible food produce by the swiftlet's saliva, which is rich in sialic acids. Sialic acids are monosaccharides that play a vital role in maintaining the integrity and proper function of the human organs, including kidneys. EBN also contains epidermal growth factor, which is widely believed to have rejuvenation and tissue repairing properties. We initiate this study to study the potential reno-protective effect of edible bird's nests by studying the Wistar rat model of gentamicin-induced AKI. Besides renal profiles, renal histology was also semiquantitatively assessed. In our study, pre-treatment with EBN prevented and ameliorated the gentamicin-induced AKI. To a lesser extent, post-treatment with EBN also protected the kidney from the toxic effect of gentamicin. Our findings are highly indicative that EBN possesses reno-protective properties.

Arsenic hyperaccumulation by Pteris vittata and Pityrogramma calomelanos: a comparative study of uptake efficiency in arsenic-treated soils and waters.

This work comprised of the comparative study of arsenic (As) uptake efficiency by Pteris vittata and Pityrogramma calomelanos grown in (i) As amended soils (0-600 ppm) and (ii) As tainted water (40 ppb) using a new compact continuous flow phytofiltration system in a tropical greenhouse. The As hyperaccumulation efficiency was dependent on the growth medium for the two fern species. The highest level of As detected in the fronds of P. vittata was 19,300+/-190 ppm (dry weight basis) and 11,600+/-230 ppm for Pityrogramma calomelanos, after growing for 78 days in soils amended with As. In the compact continuous flow As phytofiltration system experiments, Pityrogramma calomelanos was found to perform better than P. vittata in phytofiltrating As contaminated water under waterlogged conditions. During the 167 h of phytofiltration experiment, the removal efficiency was approximately 99% and 67% for Pityrogramma calomelanos and P. vittata systems respectively, based on an initial 40 ppb As. Pityrogramma calomelanos also required a shorter acclimatization time than P. vittata under waterlogged conditions.

Identification of aberrant promoter methylation of EDNRB gene in esophageal squamous cell carcinoma.

Epigenetic silencing of tumor suppressor genes is a major contributor to neoplastic transformation and is an area of intense research. The purpose of the present study was to identify the epigenetic changes in esophageal squamous cell carcinoma (ESCC). Methylation-sensitive arbitrarily primed polymerase chain reaction analysis was used on 21 matched ESCC tumors and adjacent normal tissues. Through this screen we identified a frequently methylated fragment that showed a high homology to the 5' CpG island of endothelin receptor type B (EDNRB) gene. The methylation status of the EDNRB gene was then detected by bisulfite sequencing and the levels of EDNRB mRNA were detected by quantitative real-time polymerase chain reaction (PCR). In addition, the effects of a methylation inhibitor 5-aza-2'-deoxycytidine on EDNRB mRNA expression was determined in cells of an ESCC cell lines. Hypermethylation of the 5' CpG island of EDNRB was found in 5 out of 21 (23.8%) primary tumors. Real-time PCR analysis demonstrated that EDNRB mRNA expression was significantly reduced in tumors showing high promoter methylation compared with paired normal tissues, whereas there is no significant difference between other paired samples. In addition, treatment of ESCC cell line with 5-aza-2'-deoxycytidine led to reexpression of the EDNRB transcript, which is correlated with the reversal of the methylation status of EDNRB promoter. In conclusion, promoter hypermethylation of EDNRB gene, which is associated with the loss of EDNRB mRNA expression, may play a role in the development of ESCC.

Aberrant promoter methylation of the TPEF gene in esophageal squamous cell carcinoma.

Aberrant methylation of tumor suppressor genes plays an important role in the development of esophageal squamous cell carcinoma (ESCC). The purpose of the present study was to identify the epigenetic changes in ESCC. Methylation-sensitive arbitrarily primed polymerase chain reaction (MS AP-PCR) analysis was used on 22 matched ESCC tumors and adjacent normal tissues. Through this screen we identified a frequently methylated fragment that showed a high homology to the 5'-CpG island of the gene encoding a transmembrane protein containing epidermal growth factor and follistatin domains (TPEF). The methylation status of the TPEF gene was then detected by bisulfite sequencing and the levels of TPEF mRNA were detected by RT-PCR. In addition, the effects of a methylation inhibitor 5-aza-2'-deoxycytidine on TPEF mRNA expression was determined in cells of ESCC cell lines. Hypermethylation of the 5'-CpG island of TPEF was found in 12 of 22 (54.5%) primary tumors. Reverse transcription PCR analysis demonstrated that TPEF mRNA expression was significantly lower in tumors than in adjacent normal tissues, which is associated with promoter hypermethylation. In addition, treatment of ESCC cell lines with 5-aza-2'-deoxycytidine led to re-expression of the TPEF transcript. In conclusion, we observed promoter of TPEF gene is frequently hpermethylated, and is associated with the loss of TPEF mRNA expression in ESCC samples. Promoter hypermethylation of TPEF gene may play a role in the development of ESCC.

Effect of Edible Bird's Nest Extract on Lipopolysaccharide-Induced Impairment of Learning and Memory in Wistar Rats.

Cognitive disability is a common feature associated with a variety of neurological conditions including Alzheimer's Disease (AD), Parkinson's Disease (PD), brain injury, and stroke. Emerging evidence has demonstrated that neuroinflammation plays an important role in the development of cognitive impairment. Current available therapies are relatively ineffective in treating or preventing cognitive disabilities, thus representing an important, unfulfilled medical need. Hence, developing potential treatment is one of the major areas of research interest. Edible bird's nests (EBN) are nests formed by swiftlet's saliva containing sialic acid, which is believed to improve brain function. This present study was embarked upon to evaluate the learning and memory enhancing potential effect of EBN by using Morris water maze test in a Wistar rat model of LPS-induced neuroinflammation. LPS elicited cognitive impairment in the rats by significantly increasing the escape latency while decreasing the number of entries in the probe trial, which are coupled with increased production of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6) and oxidative markers (ROS and TBARS) in the hippocampus. Treatment with EBN (125 mg/kg, 250 mg/kg, and 500 mg/kg; p.o.) effectively reversed the effect of LPS on escape latency and probe trial and, in addition, inhibited the LPS-induced upregulation of proinflammatory cytokines and oxidative markers. These findings are suggestive that there is existence of neuroprotective effect contained inside the edible bird's nest.

Myeloid sarcoma: An unusual and rare laryngeal presentation.

INTRODUCTION: Myeloid Sarcoma (MS) or Granulocytic Sarcoma is an uncommon laryngeal malignancy. It may arise from myelodysplastic syndromes, malignancy or de novo. Presentation in the larynx is rare and some may present with Acute Myeloid Leukaemia (AML) whereby the later may be asymptomatic. CASE PRESENTATION: A 44-year-old South East Asian lady presented with a six months history of hoarseness, shortness of breath, reduced exercise tolerance, weight loss and laryngeal irritation. Symptoms progressed to coughing with liquids two months prior. On examination, she had a resting biphasic stridor and laryngoscopy revealed right immobile vocal cord with a firm right ventricle mass extending into the right paraglottic space. She was pale and haematology investigations revealed microcytic hypochromic anaemia. Magnetic Resonance Imaging (MRI) of the neck and thorax showed thickening of the right false cord, true cord and aryepiglottic fold. A biopsy taken during endolaryngeal microsurgery (ELMS) confirmed myeloid sarcoma of the right ventricle and para glottic mass. Further investigation revealed a background of AML and she then underwent chemotherapy. DISCUSSION: MS is a rarity with only nine reported cases between the years of 1954 until 2015. Immunohistochemistry and immunophenotyping are definite for diagnosis confirmation as MS cells often exhibit myeloperoxidase (MPO), lymphocyte common antigen (LCA) and CD117 markers. MS is treated with are chemotherapy (either systemic or intrathecal), radiotherapy, surgical excision or in combination. Systemic chemotherapy has better efficacy and prognosis as compared to localised treatment of radiotherapy or surgical excision. However, there has yet to be a definitive chemotherapy protocol. Prognosis is poor with a 5-year survival rate of 48%. CONCLUSION: Although laryngeal MS is a rare phenomenon, early recognition is key and patients should always be investigated for an underlying myeloproliferative or dysplastic disease.

Separation of kaempferols in Impatients balsamina flowers by capillary electrophoresis with electrochemical detection.

Capillary electrophoresis with wall-jet amperometric detection was used to detect kaempferol and its derivatives kaempferol-3-glucoside, kaempferol-3-glucosylrhamnoside and kaempferol-3-(p-coumaroyl)glucoside. The influence of buffer pH on separation was investigated and optimized. With a phosphate buffer at pH 7.5, nearly complete separation of the four kaempferols was achieved according to their different electrophoretic mobilities. The detection potential was also evaluated and optimized. At detection potential of +0.80 V vs. saturated calomel electrode, an amperometric response with high sensitivity and stability was obtained for these four compounds. Detection limit estimated for all the kaempferols examined was less than 1.4 fmol, based on S/N=3. The use of this method for the separation and detection of these compounds present in balsam flowers (Impatiens balsamina) is reported.

Outlining the prostate boundary using the harmonics method.

In a computerised ultrasound image guidance for automated prostatectomy system, it is necessary to identify a smooth, continuous contour for the prostate (boundary) from the ultrasound image. The radial bas-relief (RBR) method, which has been reported previously, can extract a skeletonised image from an ultrasound image automatically. After this process the prostate boundary is clearly revealed. However, analysis of the image is far from complete, as there are many spurious branches that create too much ambiguity for the system to define the actual boundary. There are also sections missing from the prostate boundary. Therefore further post-processing is required to describe and define the prostate boundary. In the paper, the harmonics method is used to describe the prostate boundary. The harmonics method uses Fourier information for noise removal and encodes a smooth boundary. The results of using the harmonics method after application of the RBR method on ultrasound images are presented. Factors that affect the performance are also highlighted and discussed.

An investigation of biooxidation ability of Acidithiobacillus ferrooxidans using NMR relaxation measurement.

NMR relaxation measurements can provide a simple means for understanding biological activity of cells in solution with known composition. It has the advantage that it is an in situ, non-intrusive technique, and the acquisition is fast. The iron oxidation ability of Acidithiobacillus ferrooxidans was investigated using NMR relaxation measurements. The transversal relaxation is characterized by a time constant, T2, which is sensitive to the chemical environment. Fe³âº ion has more significant T2 shortening than Fe²âº ion. In the presence of A. ferrooxidans in solutions containing Fe²âº ion, T2 shortening was found with increasing time as the bacteria oxidize Fe²âº to Fe³âº ions. In the optimal growth medium, the bacteria concentration increased 80 times and high iron oxidation rate was found. In 10 mM K2SO4 medium, however, bacteria concentration remained almost unchanged and the iron oxidation rate was significantly lower.

Scanning electron micrographs of two species of Sturnophagoides (Acari: Astigmata: Pyroglyphidae) mites in Malaysia.

Scanning electron microscope (SEM) images of two dust mites, Sturnophagoides brasiliensis and Sturnophagoides halterophilus, are presented to provide an improved visualization of the taxonomic characters of these mites. Sturnophagoides halterophilus can be differentiated from S. brasiliensis by their expanded genu and femur of leg I. The differences in morphology of male and female S. brasiliensis are also discussed.

Scanning electron micrographs of Blomia tropicalis (Acari:Astigmata: Echimyopodidae), a common house dust mite in Malaysia.

Many finer taxonomic characters of Blomia tropicalis are not distinctly visible under conventional light microscopy. Scanning electron micrographs of this mite are therefore presented in this paper for better appreciation of the inconspicuous features of the morphology of the species. The differences in morphology of male and female B. tropicalis are also briefly discussed.

Spectral characterization of yeast cells with an epitaxy-based UV-Vis optical sensor.

The optical spectra of yeast cells in phosphate buffer saline (PBS) were analyzed with an optical UV-vis sensor based on a shallow p(+)n junction realized in a low doped n-type epitaxial silicon layer grown on a strongly doped n(+) substrate. The presence of the n/n(+) interface allows a significantly enhanced sensitivity, due to an increased collection of carriers photogenerated both by short and large wavelengths in the range 250...800 nm. In our experiments the optical absorption of yeast cells was investigated in the wavelength range 250...500 nm as a function of the cells concentration in PBS in the range of 6 x 10(6)-2 x 10(8) cells/ml. The main absorption peaks were found at 310, 350, 400 and 427 nm, respectively. A significant red shift of the wide absorption band at 427 nm has been observed when increasing cell concentration. This red shift behaviour was nonlinear, with saturation observed for yeast concentrations larger than 5 x 10(7) cells/ml. The half-peak bandwidth of this peak also showed a most significant nonlinear variation. These findings suggest that monitoring the parameters of the absorption band at 427 nm versus cells concentration could be used, e.g. using a dedicated integrated spectrometric microsystem, for fast quantitative measurements of yeast cell concentrations in various bio-samples, with possible applications in the food industry.

Applications of a versatile sol-gel derived renewable electrode for capillary electrophoresis.

A new electrode has been developed and applied for amperometric detection in capillary electrophoresis (CE), comprised of carbon sol-gel composite material. The versatility of the sol-gel technique permits the flexible configuration of the electrode. The performance of such a sol-gel carbon composite electrode (CCE) is first evaluated in a typical CE application for the detection of purine-based compounds. Application of the CCE is also demonstrated for the detection of phenolic compounds in a micellar system. Separation resolution for non-ionic phenolic compounds can significantly be enhanced by introducing sodium dodecyl sulfate (SDS) at a concentration above its critical micelle concentration (cmc) to the buffer. Another design of the CCE incorporating the electrocatalyst Cu2O is employed for the analysis of sugars and organic acids based on dynamic modification with cetyltrimethylammonium bromide (CTAB). It has been found that the presence of surfactant in the separation buffer does not adversely influence the electrochemical detection using a sol-gel derived carbon electrode.

Voltammetric determination of platinum in inorganic complexes and in water, geological and biological matrices using laboratory- and field-based instrumentation.

The extremely sensitive catalytic hydrogen ion reduction wave observed after the formation of a platinum-formazone complex at a mercury electrode in a hydrazine-formaldehyde-H2SO4 medium has been utilised to determine platinum voltammetrically in well characterised platinum inorganic complexes (oxidation states O, II and IV) and in biological, geological and water samples. Experimental conditions have been optimised and sample-treatment procedures for various matrices have been critically evaluated for the quantification of platinum by the standard additions method. The determination of platinum in geological samples by this method has been compared with an inductively coupled plasma mass spectrometric method. Both conventional and portable field-based instrumentation have been used in the studies, and the possibility of developing a field-based method for the determination of platinum has been investigated. Despite the inherent sensitivity of the method, which enables concentrations down to 0.01 p.p.b. to be detected in simple matrices, natural levels in water and biological materials, where matrix effects suppress the voltammetric response, are often below the detection limit.