Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp Production

An engineered aquatic ecosystem was specifically designed to bioremediate selenium (Se), occurring as oxidized inorganic selenate from hypersalinized agricultural drainage water while producing brine shrimp enriched in organic Se and omega-3 and omega-6 fatty acids for use in value added nutraceutical food supplements. Selenate was successfully bioremediated by microalgal metabolism into organic Se (seleno-amino acids) and partially removed via gaseous volatile Se formation. Furthermore, filterfeeding brine shrimp that accumulated this organic Se were removed by net harvest. Thriving in this engineered pond system, brine shrimp (Artemia franciscana Kellogg) and brine fly (Ephydridae sp.) have major ecological relevance as important food sources for large populations of waterfowl, breeding, and migratory shore birds. This aquatic ecosystem was an ideal model for study because it mimics trophic interactions in a Se polluted wetland. Inorganic selenate in drainage water was metabolized differently in microalgae, bacteria, and diatoms where it was accumulated and reduced into various inorganic forms (selenite, selenide, or elemental Se) or partially incorporated into organic Se mainly as selenomethionine. Brine shrimp and brine fly larva then bioaccumulated Se from ingesting aquatic microorganisms and further metabolized Se predominately into organic Se forms. Importantly, adult brine flies, which hatched from aquatic larva, bioaccumulated the highest Se concentrations of all organisms tested

Cloning, expression, and characterization of lactic acid bacteria recombinant prolidases

Lactobacillus plantarum (Lb. plantarum) NRRL B4496 and Lactococcus lactis (Lc. lactis) NRRL B1821 prolidase genes were isolated, cloned, and sequenced. The sequence-confirmed genes were subcloned into the expression systems. The recombinant prolidases from the pKK223-3 systems were purified through ammonium sulphate precipitation and anion-exchange column chromatography. Recombinant Lb. plantarum prolidase, however, demonstrated a loss of activity during the purification. The following characterization work was performed on purified recombinant Lc. lactis prolidase. The mass spectroscopic result and the molecular modelling suggested a 80 kDa homodimer with two metal cations at the catalytic centre of the prolidase. The optimum temperature was 50 ºC and showed more than 50% activities between 40 and 55 ºC. The enzyme was most stable at 30 ºC and withstood 20 min of heat-treatment up to 60 ºC, however, lost activity over 70 ºC. Circular dichroism indicated a denaturation temperature of 67 ºC. The optimum pH was 6.5 for hydrolyzing Leu-Pro and the enzyme did not display any activity below pH 5.5 nor above pH 7 with this peptide. However, Phe-Pro was hydrolyzed the fastest at pH 7 and Arg-Pro had a maximum rate at pH 9. This metallopeptidase exhibited a broad range of metal cation preference, hydrolyzing Leu-Pro with Mn++, Co++, Zn++, Ca++, and Mg++. Further kinetic analysis showed unusual allostery of the enzyme (Hill coefficient: 1.3). The unique substrate intakes onGlu-Pro and tripeptides were observed while Val-Pro was not hydrolyzed. The molecular modelling of this prolidase suggested a difference in the substrate specificity resulting from a loop structure, L33 to R40, near the substrate binding site

Biotransformation and Interactions of Selenium with Mixed and Pure Culture Biofilms

Biofilms have been reported to have an important role in the biogeochemical cycling of toxic elements in aquatic systems. Despite this important role, the complexity of biofilms and chemical and physical modifications that occur in conventional microscopic techniques hinder research progress. Thus, this research utilized a suite of less destructive synchrotron-based techniques to investigate selenium biotransformation in biofilms. Natural biofilm collected from a coal mine-affected field site was examined with X-ray absorption spectroscopy (XAS), the results of which suggested the presence of methylated and elemental selenium. Biofilms generated in the laboratory using collected coal mine-affected water were investigated using confocal laser scanning microscopy (CLSM), (μ-)XAS and extended X-ray absorption fine structure (EXAFS). The results showed biotransformation of added oxyanion species (selenate, selenite, arsenate or arsenite). Micro X-ray fluorescence imaging (μ-XRF) and μ-XAS combined with CLSM revealed that selenium was highly localized in the biofilm in chemically reduced forms. Isolation and partial 16S rRNA gene sequencing suggested there were 4 principle bacterial genera responsible for these biotransformations of selenium. Further examination of multispecies biofilm and pure-culture biofilm (Arthrobacter sp SASK-Se22) exposed to high concentrations of selenate and selenite was carried out using synchrotron-based nano-scale scanning transmission X-ray microscopy (STXM) and nano-XRF imaging at the selenium L and K near-edges. These results demonstrated that selenium was biotransformed to nano-particulate elemental selenium and that the selenium particles were closely associated with lipid within the biofilm. The distributions of selenate and selenite as well as elemental selenium within this complex biofilm structure were investigated using a novel combination of STXM and XRF on identical areas of biofilms. Transmission electron microscopy showed that the biogenic elemental selenium was sub-micron-sized, ranging from 50 to 700 nm in diameter, and was closely associated with microorganisms. The presence of submicron-sized elemental selenium may suggest possible applications of the biofilms in bioremediation or in the semiconductor industry where micro- to nano- sized selenium particles are in great demand. Overall, this research demonstrated a novel application of synchrotron-based spectroscopic and imaging techniques to biofilm research, the results of which advance understanding of selenium biotransformation in multispecies and pure-culture biofilms

THE ANTERIOR CRUCIATE LIGAMENT INURY PREVENTION PROGRAM: A META-ANALYSIS

The purpose of this study was to evaluate the effect of a neuromuscular protocol on the prevention of anterior cruciate ligament (ACL) injury by performing meta-analysis. An extensive literature review was conducted to identify relevant studies, and eventually, only seven randomized controlled trials or prospective cohort studies were included in the analysis. Subgroup analysis revealed that an age under 18, soccer rather than handball, pre- and in-season training rather than either pre or in-season training, and the plyometrics and strengthening components rather than balancing were significant. Metaanalysis showed that pre- and in-season neuromuscular training with an emphasis on plyometrics and strengthening exercises was effective at preventing ACL injury in female athletes, especially in those under 18 years of age

Macrolide resistance and genotypic characterization of Streptococcus pneumoniae in Asian countries: a study of the Asian Network for Surveillance of Resistant Pathogens (ANSORP)

Objectives: To characterize mechanisms of macrolide resistance among Streptococcus pneumoniae from 10 Asian countries during 1998-2001. Methods: Phenotypic and genotypic characterization of the isolates and their resistance mechanisms. Results: Of 555 isolates studied, 216 (38.9%) were susceptible, 10 (1.8%) were intermediate and 329 (59.3%) were resistant to erythromycin. Vietnam had the highest prevalence of erythromycin resistance (88.3%), followed by Taiwan (87.2%), Korea (85.1%), Hong Kong (76.5%) and China (75.6%). Ribosomal methylation encoded by erm(B) was the most common mechanism of erythromycin resistance in China, Taiwan, Sri Lanka and Korea. In Hong Kong, Singapore, Thailand and Malaysia, efflux encoded by mef(A) was the more common in erythromycin-resistant isolates. In most Asian countries except Hong Kong, Malaysia and Singapore, erm(B) was found in >50% of pneumococcal isolates either alone or in combination with mef(A). The level of erythromycin resistance among pneumococcal isolates in most Asian countries except Thailand and India was very high with MIC90s of >128 mg/L. Molecular epidemiological studies suggest the horizontal transfer of the erm(B) gene and clonal dissemination of resistant strains in the Asian region. Conclusion: Data confirm that macrolide resistance in pneumococci is a serious problem in many Asian countries

Association between cord blood 25-hydroxyvitamin D concentrations and respiratory tract infections in the first 6 months of age in a Korean population: a birth cohort study (COCOA)

PurposePrevious studies suggest that the concentration of 25-hydroxyvitamin D [25(OH)D] in cord blood may show an inverse association with respiratory tract infections (RTI) during childhood. The aim of the present study was to examine the influence of 25(OH)D concentrations in cord blood on infant RTI in a Korean birth cohort.MethodsThe levels of 25(OH)D in cord blood obtained from 525 Korean newborns in the prospective COhort for Childhood Origin of Asthma and allergic diseases were examined. The primary outcome variable of interest was the prevalence of RTI at 6-month follow-up, as diagnosed by pediatricians and pediatric allergy and pulmonology specialists. RTI included acute nasopharyngitis, rhinosinusitis, otitis media, croup, tracheobronchitis, bronchiolitis, and pneumonia.ResultsThe median concentration of 25(OH)D in cord blood was 32.0 nmol/L (interquartile range, 21.4 to 53.2). One hundred and eighty neonates (34.3%) showed 25(OH)D concentrations less than 25.0 nmol/L, 292 (55.6%) showed 25(OH)D concentrations of 25.0-74.9 nmol/L, and 53 (10.1%) showed concentrations of ≥75.0 nmol/L. Adjusting for the season of birth, multivitamin intake during pregnancy, and exposure to passive smoking during pregnancy, 25(OH)D concentrations showed an inverse association with the risk of acquiring acute nasopharyngitis by 6 months of age (P for trend=0.0004).ConclusionThe results show that 89.9% of healthy newborns in Korea are born with vitamin D insufficiency or deficiency (55.6% and 34.3%, respectively). Cord blood vitamin D insufficiency or deficiency in healthy neonates is associated with an increased risk of acute nasopharyngitis by 6 months of age. More time spent outdoors and more intensified vitamin D supplementation for pregnant women may be needed to prevent the onset of acute nasopharyngitis in infants

Cordycepin inhibits human ovarian cancer by inducing autophagy and apoptosis through Dickkopf-related protein 1/β-catenin signaling

Cordycepin, the major active component from Cordyceps militaris, has been reported to significantly inhibit some types of cancer; however, its effects on ovarian cancer are still not well understood. In this study, we treated human ovarian cancer cells with different doses of cordycepin and found that it dose-dependently reduced ovarian cancer cell viability, based on Cell counting kit-8 reagent. Immunoblotting showed that cordycepin increased Dickkopf-related protein 1 (Dkk1) levels and inhibited β-catenin signaling. Atg7 knockdown in ovarian cancer cells significantly inhibited cordycepin-induced apoptosis, whereas β-catenin overexpression abolished the effects of cordycepin on cell death and proliferation. Furthermore, we found that Dkk1 overexpression by transfection downregulated the expression of c-Myc and cyclin D1. siRNA-mediated Dkk1 silencing downregulated the expression of Atg8, beclin, and LC3 and promoted β-catenin translocation from the cytoplasm into the nucleus. These results suggest that cordycepin inhibits ovarian cancer cell growth, possibly through coordinated autophagy and Dkk1/β-catenin signaling. Taken together, our findings provide new insights into the treatment of ovarian cancer using cordycepin

A Nasogastric Tube Inserted into the Gastrocutaneous Fistula

We reported a case in which a nasogastric tube was inserted into the gastrocutaneous fistula, diagnosed by abdominal computed tomography. A 78-year-old man with a history of recurrent cerebral hemorrhage had a percutaneous endoscopic gastrostomy tube due to dysphagia for 2 years. However, soft tissue infection at the gastrostomy site caused the removal of the tube. Immediately, antibiotic agents were infused. For appropriate hydration and medication, a nasogastric tube was inserted. However, there was no significant improvement of the soft tissue infection. Moreover, the amount of bloody exudate increased. Abdominal computed tomography revealed the nasogastric tube placed under the patient's skin via gastrocutaneous fistula. The nasogastric tube was removed, and an antibiotic agents were maintained. After 3 weeks, the signs of infection fully improved, and percutaneous endoscopic gastrostomy was performed again. This case shows necessities of an appropriate interval between removal of the gastrostomy tube and insertion of a nasogastric tube, and suspicion of existence of gastrocutaneous fistula

Insulin Facilitates the Recovery of Myocardial Contractility and Conduction during Cardiac Compression in Rabbits with Bupivacaine-Induced Cardiovascular Collapse

Bupivacaine inhibits cardiac conduction and contractility. Insulin enhances cardiac repolarization and myocardial contractility. We hypothesizes that insulin therapy would be effective in resuscitating bupivacaine-induced cardiac toxicity in rabbits. Twelve rabbits were tracheally intubated and midline sternotomy was performed under general anesthesia. Cardiovascular collapse (CVC) was induced by an IV bolus injection of bupivacaine 10 mg/kg. The rabbits were treated with either saline (control) or insulin injection, administered as a 2 U/kg bolus. Internal cardiac massage was performed until the return of spontaneous circulation (ROSC) and the time to the return of sinus rhythm (ROSR) was also noted in both groups. Arterial blood pressure, and electrocardiography were continuously monitored for 30 min and plasma bupivacaine concentrations at every 5 min. The ROSC, ROSR and normalization of QRS duration were attained faster in the insulin-treated group than in the control group. At the ROSC, there was a significant difference in bupivacaine concentration between two groups. Insulin facilitates the return of myocardial contractility and conduction from bupivacaine-induced CVC in rabbits. However, recovery of cardiac conduction is dependent mainly on the change of plasma bupivacaine concentrations