In vitro phosphorylation as tool for modification of silk and keratin fibrous materials

An overview is given of the recent work on in vitro enzymatic phosphorylation of silk fibroin and human hair keratin. Opposing to many chemical "conventional" approaches, enzymatic phosphorylation is in fact a mild reaction and the treatment falls within "green chemistry" approach. Silk and keratin are not phosphorylated in vivo, but in vitro. This enzyme-driven modification is a major technological breakthrough. Harsh chemical chemicals are avoided, and mild conditions make enzymatic phosphorylation a real "green chemistry" approach. The current communication presents a novel approach stating that enzyme phosphorylation may be used as a tool to modify the surface charge of biocompatible materials such as keratin and silk

Characterization of an extracellular lipase and its chaperone from Ralstonia eutropha H16

Lipase enzymes catalyze the reversible hydrolysis of triacylglycerol to fatty acids and glycerol at the lipid–water interface. The metabolically versatile Ralstonia eutropha strain H16 is capable of utilizing various molecules containing long carbon chains such as plant oil, organic acids, or Tween as its sole carbon source for growth. Global gene expression analysis revealed an upregulation of two putative lipase genes during growth on trioleate. Through analysis of growth and activity using strains with gene deletions and complementations, the extracellular lipase (encoded by the lipA gene, locus tag H16_A1322) and lipase-specific chaperone (encoded by the lipB gene, locus tag H16_A1323) produced by R. eutropha H16 was identified. Increase in gene dosage of lipA not only resulted in an increase of the extracellular lipase activity, but also reduced the lag phase during growth on palm oil. LipA is a non-specific lipase that can completely hydrolyze triacylglycerol into its corresponding free fatty acids and glycerol. Although LipA is active over a temperature range from 10 °C to 70 °C, it exhibited optimal activity at 50 °C. While R. eutropha H16 prefers a growth pH of 6.8, its extracellular lipase LipA is most active between pH 7 and 8. Cofactors are not required for lipase activity; however, EDTA and EGTA inhibited LipA activity by 83 %. Metal ions Mg[superscript 2+], Ca[superscript 2+], and Mn[superscript 2+] were found to stimulate LipA activity and relieve chelator inhibition. Certain detergents are found to improve solubility of the lipid substrate or increase lipase-lipid aggregation, as a result SDS and Triton X-100 were able to increase lipase activity by 20 % to 500 %. R. eutropha extracellular LipA activity can be hyper-increased, making the overexpression strain a potential candidate for commercial lipase production or in fermentations using plant oils as the sole carbon source.Malaysia-MIT Biotechnology Partnership Programm

Current Treatment of Endolymphatic Sac Tumor of the Temporal Bone

An endolymphatic sac tumor (ELST) is a rare, indolent but locally aggressive tumor arising in the posterior petrous ridge. Patients present with sensorineural hearing loss and tinnitus. As the tumor progresses, patients may experience vertigo, ataxia, facial nerve paresis, pain and otorrhea. Most patients present in their 4th or 5th decade with a wide age range. Patients with von Hippel–Lindau disease have an increased likelihood of developing ELST. Histologically, ELST is a low-grade adenocarcinoma. As it progresses, it destroys bone and extends into adjacent tissues. The likelihood of regional or distant metastases is remote. The optimal treatment is resection with negative margins. Patients with positive margins, gross residual disease, or unresectable tumor are treated with radiotherapy or radiosurgery. Late recurrences are common, so long follow-up is necessary to assess efficacy. The likelihood of cure depends on tumor extent and is probably in the range of 50–75%

Low energy gamma-ray spectrometry — A technique for estimation of high grade uranium in geological samples

494-502Low Energy Gamma-Ray Spectrometry (LEGS) has been proved to be a rapid technique for analyzing high-grade uranium in geological samples. From the low energy portion between (40-400 keV) of the gamma-ray spectrum of uranium and thorium series, the contents of uranium, its daughter radium (eq), and thorium are determined. This gives significant information about the geochemical anomalies. A standard gamma ray spectrometer with a 1¾” 2” well type NaI (Tl) gamma detector constitutes the instrumentation requirements of this technique. Sample weighing about a few grams in a glass vial is used for analysis. A detailed study on the contribution of uranium daughter’s energies in gamma spectrum of uranium has made the system more efficient for analyzing high grade (20%) uraniferous samples. Minimum personal exposure and an excellent correlation of uranium values with the chemical results have made this technique a versatile one in high-grade uranium exploration programme. This paper deals with problems faced by the conventional methods that is Beta-Gamma and High Energy Gamma-Ray Spectrometry used for determining the contents of uranium and thorium in high-grade uraniferous geological samples and the advantage of this technique over them

Spectral gamma ray logging: A cost-effective method for uranium exploration

The most useful technique in uranium exploration program is undoubtedly radiometric surveys. This is due to the fact that uranium emits gamma rays ranging from as low as 47kev to 2.2Mev, which can be detected and quantified using suitable radiation detector. Combination of aerial radiometric surveys, ground examination of the detected anomalies, followed by drilling and gamma ray logging of drilled boreholes has resulted in the identification of large uranium resources. Borehole logging provides the most important subsurface information required for the uranium exploration program. An area known to contain only uranium, computed gamma ray logging with a Geiger Muller (GM) Detector rapidly gives the required subsurface radioactivity information whereas, in a heterogeneously mineralized area of uranium with thorium, logging data using GM detector may mislead to wrong interpretation. Under such condition, using the principle of gamma ray spectrometry, scintillation detector-based spectral gamma ray logging is carried out. Identifying uranium in the presence of thorium is a complex process and this paper deals with a case study on the spectral gamma ray logging carried out to locate the subsurface uraniferous zone in Pakkanadu area, Salem district of Tamil nadu, where the surface anomaly indicated the presence of high thorium content. The various limitations such as small detector size, large sample volume, high-correction factor required for quantifying the individual elements, and the study carried out for optimizing the time required for data acquisition are discussed