A quinonoid is an intermediate of oxidative deamination reaction catalyzed by Dopa decarboxylase

The reactions of Dopa decarboxylase (DDC) with l- and d-enantiomers of tryptophan methyl ester are described. Although both the enantiomers bind to the active site of the enzyme with similar affinity, their binding modes are different. l-enantiomer binds in an unproductive mode, while d-enantiomer acts as an oxidative deamination substrate. For the first time a quinonoid has been detected as intermediate of this reaction. By using rapid-scanning stopped-flow kinetic technique rate constants for formation and decay of this species have been determined. All these data, besides validating the functional DDC active site model, represent an important step toward the elucidation of the catalytic pathway of oxidative deamination.     

Effects of Bacillus thuringiensis kurstaki on Malpighian tubule cells of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) larvae

In this study effects of Bacillus thuringiensis kurstaki (Btk) on Malpighian tubule cells of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) larvae was investigated by electron microscopy. 3 mg/l Btk was given with food. After Btk administration, the Malpighian tubule cells were investigated and compared with a control group. 3 and 6 hrs after Btk administration swelling in Malpighian tubule cells was observed. Swelling of mitochondria and separation of their cristae was seen after 12 hrs. After 24 hrs dissolution of the basal cytoplasm, swelling and vacuolization of all mitochondria, partial dissolution of the nucleoplasm, and swelling and separation ofmicrovilli was documented. A membrane-body in the nucleus was seen after 48 hrs. The nucleoplasm was completely dissolved after 72 hrs and after 96 hrs large vacuoles appeared in the cytoplasm and shortening of microvilli was observed.     

Enhanced kinetics of genetically engineered Burkholderia cepacia: the role of vgb in the hypoxic metabolism of 2-CBA

Application of Vitreoscilla hemoglobin (VHb) technology to 2-CBA degradation by Burkholderia cepacia strain DNT under hypoxic conditions was studied in continuous culture chemostats. Dechlorination abilities of both recombinant (VHb gene (vgb) containing) and untransformed cells were investigated at various dilution rates to ensure complete degradation of 2-CBA. As the dilution rate increased from 0.025 to 0.25 h(-1), the ratios of chloride release to degraded 2-CBA concentration decreased from 0.95 to 0.72 and from 0.89 to 0.39 for recombinant and untransformed cells, respectively. A nonstoichiometric relationship between chloride release and 2-CBA degradation was more pronounced for untransformed cells. Recombinant cell densities were 0.1-0.2. g L(-1) greater than untransformed cell densities for a range of dilution rates. As the dilution rate increased, the oxygen uptake rate (OUR) and the substrate utilization rate (SUR) decreased for both strains. The OUR/SUR ratio increased as the dilution rate increased for both strains but was much higher for the recombinant strain compared to untransformed cells. The specific 2-CBA degradation rate of recombinant cells was greater than that of untransformed cells (1.17 vs. 0.46 mg CBA (mg) day(-1), and half-saturation constants for recombinant cells were lower than those of untransformed cells (0.18 and 0.32 mg CBA L(-1), respectively). The pseudo-first-order degradation constants, k(1CBA) and k(1ACE), were higher for recombinant cells (6.5 L (mg cells)(-1) day(-1) and 95.6 L (mg cells)(-1) day(-1), respectively) than those of untransformed cells (1.44 L (mg cells)(-1) day(-1) and 73.7 L (mg cells)(-1) day(-1), respectively).     

Induction of macrophage elastase (MMP-12) gene expression by statins

The statins (including mevastatin and lovastatin) are a widely prescribed class of serum-cholesterol lowering drugs that function by inhibiting 3-hydroxymethylglutaryl coenzyme A (HMG CoA) reductase activity and cellular sterol synthesis. Statins are also widely being appreciated for their inhibitory effects upon inflammation, primarily mediated through direct regulation of inflammatory gene expression. Here we report that statins are also capable of increasing the expression of macrophage elastase (MMP-12). The induction of MMP-12 in mouse macrophages by statins is specific for HMG CoA reductase inhibition, rescued by mevalonate and not observed after inhibition of subsequent steps in the cholesterol biosynthetic pathway. Modulation of cholesterol metabolism may lead to changes in MMP-12 expression and subsequent impacts during physiological and pathophysiological states. We conclude that statins, in addition to their previously described anti-inflammatory properties, may promote the production of some proteinases from activated macrophages.     

Floristic Characteristics of the Karkamis Dam Reservoir Area and its Surroundings (Gaziantep-Sanliurfa: Turkey)

The natural flora of Karkamis Dam lake area and its surroundings was studied in 2000 and 2001 before the dam construction was completed. During the floristic surveys, 464 species of 279 genera belonging to 70 families were recorded. The number of endemic species is 14. The phytogeographic elements are represented in the study as follows; Irano-Turanian 104 (18.2%), Mediterranean 66 (11.5%), Euro-Siberian 7 (1.2%), Cosmopolitan 9 (1.5%), Sharo-Arabian 1 (0.1%). The phytogeographic region of 383 taxa (67.1%) is unknown, or multiregional. The spectrum of the basic life forms is as follows; Therophytes 50.0%, Hemicryptophytes 33.4%, Phanerophytes 5.2%, Geophytes 5.2%, Chamaephytes 4.3% and Hydrophytes 1.9%. According to the IUCN Red List Categories, 28 threatened plant species were identified in the study area.     

Inventory of the proteins in Neisseria meningitidis serogroup B strain MC58

A protein inventory of Neisseria meningitidis strain MC58, a meningococcal strain belonging to the serogroup B, was performed by proteomics. A differential extraction procedure was employed and 238 protein species were identified by 2D mini-maps and MALDI-ToF analyses. In this catalog, we detected protein products from 33 genes, which were not yet annotated in previous N. meningitidis proteomic studies. This approach is suitable for high-throughput studies on differential expression of N. meningitidis genomes.     

Examination of metal mobilization from a gunshot by scanning acoustic microscopy,scanning electron microscopy,energy-dispersive X-ray spectroscopy,and inductively coupled plasma optical emission spectroscopy: a case report

Background

Projectile foreign bodies are known to cause chronic heavy metal toxicity due to the release of metal into the bloodstream. However, the local effect around the metallic object has not been investigated and the main goal of our study is to examine the influence of the object in close proximity of the object.

Case presentation

A 36-year-old Caucasian woman with one metallic pellet close to her sciatic nerve due to a previous shotgun injury at the gluteal area presented with a diagnosis of recurrent lumbar disk herniation at L4–5 level. A physical examination confirmed chronic neuropathy and she underwent a two-stage surgery. The surgery included removal of the foreign body, followed by discectomy and fusion at the involved level. During the removal of the metallic foreign body, a tissue sample around the pellet and another tissue sample from a remote area were obtained. The samples were analyzed by scanning acoustic microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Lead, chromium, copper, cadmium, iron, manganese, selenium, and zinc elements in tissue, blood, and serum specimens were detected by inductively coupled plasma optical emission spectroscopy.

Conclusions

An acoustic impedance map of the tissue closer to the metallic body showed higher values indicating further accumulation of elements. Energy-dispersive X-ray spectroscopy results confirmed scanning acoustic microscopy results by measuring a higher concentration of elements closer to the metallic body. Scanning electron microscopy images showed that original structure was not disturbed far away; however, deformation of the structure existed in the tissue closer to the foreign body. Element analysis showed that element levels within blood and serum were more or less within acceptable ranges; on the other hand, element levels within the tissues showed pronounced differences indicating primarily lead intoxication in the proximity of the metallic body. We can state that residues of metallic foreign bodies of gunshot injuries cause chronic metal infiltration to the surrounding tissue and induce significant damage to nearby neural elements; this is supported by the results of scanning acoustic microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma optical emission spectroscopy.

     

The protein sequence of glutamate dehydrogenase from Sulfolobus solfataricus, a thermoacidophilic archaebacterium. Is the presence of N-epsilon-methyllysine related to thermostability?

The complete amino acid sequence of glutamate dehydrogenase from the thermoacidophilic archaebacterium Sulfolobus solfataricus has been determined. The sequence was reconstructed by automated sequence analysis of peptides obtained after cleavage by trypsin, cyanogen bromide, Staphylococcus aureus V8 protease and pepsin. The enzyme subunit is composed of 421 amino acid residues yielding a molecular mass of 46.078 kDa. The presence of N-epsilon-methyllysine in six positions of the sequence was observed. Comparison of the sequence of glutamate dehydrogenase from S. solfataricus with the other known primary structures of the corresponding enzyme from different sources, gives an overall identity of 9.2% and shows a symmetrical evolutionary distance of this archaebacterial protein from the two groups of vertebrate on one side and eubacterial and low eucaryote enzymes on the other side. The occurrence of specific substitutions and a possible role for N-epsilon-methylation of lysine residues are discussed in view of current hypotheses on the molecular basis of thermal adaptation of proteins.