Biodegradation of 2,4,6-trinitrotoluene (TNT) by the white-rot basidiomycete Phlebia radiata

Phlebia radiatatransformed 2,4,6-trinitrotoluene (TNT), as well as its first reduction products, the aminodinitrotoluenes, into 4-hydroxylamino-2,6-dinitrotoluene (4-OHA-2,6-DNT) and 4-amino-2,6-dinitrotoluene (4-A-2,6-DNT). No extracellular peroxidases were involved in this step. The ligninolytic extracellular fluid, assumed to contain peroxidases, did not reduce TNT. However, ligninolytic peroxidases are implicated in the transformation of the first reduction products of TNT.     

Formation of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in a model system by heating creatinine, glycine and glucose

A mixture of creatinine, glucose and glycine was heated in diethylene glycol containing 14% water for 2 h at 128 degrees C, and the mutagens formed were purified by XAD-2 column chromatography, acid-base partition, Sephadex LH-20 column chromatography, 'blue cotton' treatment and HPLC. Two mutagenic substances were isolated by HPLC. The major mutagen was identified by its UV absorption and mass and NMR spectra as 2-amino-3,8- dimethylimidazo [4,5-f]quinoxaline, which was originally isolated from fried beef. This finding supported the idea that creatinine, amino acids and sugars present in meat are precursors in the formation of the mutagenic imidazoquinoxaline derivative.     

Morpho-histological study on shoot bud regeneration in cotyledon cultures of pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis>)

Adventitious organogenetic structures were produced in vitro using cotyledon explants excised from 14 day-old pepper seedlings. The best response was observed on MS medium containing 5.7 μM indole-3-acetic acid and 8.8 μM 6-benzylaminopurine. However, when transferred onto elongation medium (MS + 2.8 μM gibberellic acid), these structures frequently developed into leaf-like features rather than into normal shoots. Interestingly, the histological study conducted on the cut end of the cotyledonary petiole revealed a direct induction of numerous teratological protuberances that arise around the cut end of the explant. On the contrary, typical organized bud meristems were rarely observed. Thus, the low number of plants obtained after transfer onto elongation medium seems to be a consequence of this teratological developmental process, frequently associated with fasciated and degenerative meristems, rather than a defect in shoot development from available meristems.     

MhcVizPipe: A Quality Control Software for Rapid Assessment of Small- to Large-Scale Immunopeptidome Datasets

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Colour duplex sonography of temporal arteries before decision for biopsy: a prospective study in 55 patients with suspected giant cell arteritis

Although a temporal artery biopsy is the gold standard for the diagnosis of giant cell arteritis (GCA), there is considerable evidence that characteristic signs demonstrated by colour duplex sonography (CDS) of the temporal arteries may be of diagnostic importance. We aimed to test the hypothesis that CDS can replace biopsy in the algorithm for the approach to diagnose GCA. Bilateral CDS was performed in consecutive patients older than 50 years with clinically suspected GCA, as well as in 15 age- and gender-matched control subjects with diabetes mellitus and/or stroke and 15 healthy subjects, to assess flow parameters and the possible presence of a dark halo around the arterial lumen. Unilateral temporal artery biopsy was then performed in patients with suspected GCA, which was directed to a particular arterial segment in case a halo was detected in CDS. Final diagnoses, after completion of a 3-month follow-up in 55 patients, included GCA (n = 22), polymyalgia rheumatica (n = 12), polyarteritis nodosa, Wegener's, and Adamantiades-Behçet's diseases (n = 3), and neoplastic (n = 8) and infectious diseases (n = 10). A dark halo of variable size (0.7–2.0 mm) around the vessel lumen was evident at baseline CDS in 21 patients (in 12 and 9 uni- or bilaterally, respectively) but in none of the controls. The presence of unilateral halo alone yielded 82% sensitivity and 91% specificity for GCA, whereas the specificity reached 100% when halos were found bilaterally. Blood-flow abnormal parameters (temporal artery diameter, peak systolic blood-flow velocities, stenoses, occlusions) were common in GCA and non-GCA patients, as well as in healthy and atherosclerotic disease-control, elderly subjects. At follow-up CDS examinations performed at 2 and 4 weeks after initiation of corticosteroid treatment for GCA, halos disappeared in all 18 patients (9 and 9, respectively). We conclude that CDS, an inexpensive, non-invasive, and easy-to-perform method, allows a directional biopsy that has an increased probability to confirm the clinical diagnosis. Biopsy is not necessary in a substantial proportion of patients in whom bilateral halo signs can be found by CDS.     

Promising Strategies for the Mineralisation of 2,4,6-trinitrotoluene

2,4,6-trinitrotoluene (TNT) is known to be one of the most common military explosives. In spite of its established toxicity and mutagenicity for many organisms, soils and groundwater are still being frequently contaminated at manufacturing, disposal and TNT destruction sites. The inability of natural aquatic and soil biota to use TNT as growth substrate has been recognized as the primary limitation in the application of bioremediation processes to contaminated environments. However, promising degradation pathways have been recently discovered which may lead to the mineralisation of TNT. Significant advances have been made in studying the mechanism of TNT denitration, which can be considered as the major reaction and the driving force towards beneficial biodegradation. The possibilities to favour TNT denitration are discussed based on current knowledge of the enzymology and genetics of denitration in nitroaromatic degrading organisms. The literature survey demonstrates that the only enzymes characterized so far for their denitrase activity towards TNT belong to the class I flavin-dependent β/α barrel oxidoreductases, also known as the “Old Yellow Enzyme” family. In addition, this review provides an overview of strategies and future directions towards a rational search for new catabolic activities, including metagenomic library screening, plus new possibilities to improve the activity of known catabolic enzymes acting on TNT, such as DNA shuffling.     

Proteomic analysis of amniotic fluid in pregnancies with Down syndrome

Proteomic analysis is widely used for the detection of diagnostic markers. In the present study amniotic fluid supernatants (AFS) from pregnancies with Down syndrome (DS) fetuses and from chromosomally normal fetuses in the 17th week of gestation were analyzed by 2-DE. Gel comparison revealed significant differences in the two groups. Spots with different expression levels were excised and proteins were identified by MALDI-MS and nano-ESI-MS/MS. Splicing factor arginine/serine-rich 4 (SFRS4; Q08170) was present only in AFS from DS fetuses and completely absent in the control group. Quantitative differences were detected for alpha-1-microglobulin (AMBP; P02760), collagen alpha 1 (I) chain (CO1A1; P02452), collagen alpha 1 (III) chain (CO3A1; P02461), collagen alpha 1 (V) chain d (CO5A1; P20908), and basement membrane-specific heparin sulfate proteoglycan core protein (PGBM; P98160). These proteins were increased in cases with DS, whereas protein IBP-1 (P08833) was decreased by 40% compared with chromosomally normal fetuses. Four proteins, CO1A1, CO3A1, CO5A1, and PGBM, appeared as fragments. As differentially expressed proteins were present in all pregnancies with DS tested, they may represent useful potential markers for prenatal diagnosis. However, for protein biomarkers to be of any clinical utility, systematic analysis of the maternal serum should be conducted.     

Cascade pattern recognition structure for improving quantitative assessment of estrogen receptor status in breast tissue carcinomas

OBJECTIVE: To develop and validate a computer-based approach for the quantitative assessment of estrogen receptor (ER) status in breast tissue specimens for breast cancer management. STUDY DESIGN: Microscopy images of 32 immunohistochemically (IHC) stained specimens of breast cancer biopsies were digitized and were primarily assessed for ER status (percentage of positively stained nuclei) by a histopathologist. A pattern recognition system was designed for automatically assessing the ER status of the IHC-stained specimens. Nuclei were automatically segmented from background by a pixel-based unsupervised clustering algorithm and were characterized as positively stained or unstained by a supervised classification algorithm. This cascade structure boosted the system's classification accuracy. RESULTS: System performance in correctly characterizing the nuclei was 95.48%. When specifying each case's ER status, system performance was statistically not significantly different to the physician's assessment (p = 0.13); when ranking each case to a particular 5-scale ER-scoring system (giving the chance of response to endocrine treatment), the system's score and the physician's score were in agreement in 29 of 32 cases. CONCLUSION: The need for reliable and operator independent ER-status estimation procedures may be served by the design of efficient pattern recognition systems to be employed as support opinion tools in clinical practice.