Detection of Candida by calcofluor white

OBJECTIVE

To assess the efficacy of calcofluor white (CFW) is compared to Gram stain and periodic acid-Schiff in detection of Candida in oral precancer and cancer.

STUDY DESIGN

The study group consisted of patients with precancer (n = 45), cancer (n = 45) and control group (n = 45). Presence of Candida was confirmed by culture inoculation along with a germ tube and carbohydrate fermentation test. The cytopathologic smears were analyzed by Papanicolaou-CFW and Gram staining, whereas, tissue sections were stained by periodic acid-Schiff and CFW staining.

RESULTS

Candida albicans was the predominant species identified. A highly significant association of Candida was seen more often in cancer than in precancer. Both in cytology and histopathology Candida detection by CFW was higher. In precancer it was 48.88% in smears and 40% in tissue sections, whereas, in cancer 60% in smears and 55.55% in histopathology.

CONCLUSION

Among the various diagnostic tools used in the present study, the use of CFW is seen to be a simple, effective, rapid and reliable method, both in cytopathology and histopathology.

Anaerobic biodegradability and inhibitory effects of some anionic and cationic surfactants

The anaerobic biodegradability and inhibitory effects on the methane production of three different surfactants, two anionic: sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS), and a cationic surfactant: trialkyl-methylammonium chloride (TMAC), were evaluated with two different anaerobic sludges, granular and flocculent. Five different concentrations of the surfactants, 5, 50, 100, 250 and 500 mg/L, were tested. SLS was biodegraded at concentrations of 5, 50 and 100 mg/L with flocculent sludge and at 100 and 250 mg/L with granular sludge. However an inhibitory effect on methane production was observed in both sludges at 500 mg/L. The results indicate that SDBS was not biodegradable under anoxic conditions. TMAC was slightly degraded 50 and 100 mg/L with the flocculent sludge, and from 100 to 500 mg/L with the granular sludge.

GIGANTEA is a component of a regulatory pathway determining wall ingrowth deposition in phloem parenchyma transfer cells of Arabidopsis thaliana

Transfer cells are specialised transport cells containing invaginated wall ingrowths that generate an amplified plasma membrane surface area with high densities of transporter proteins. They trans-differentiate from differentiated cells at sites at which enhanced rates of nutrient transport occur across apo/symplasmic boundaries. Despite their physiological importance, little is known of the molecular mechanisms regulating construction of their intricate wall ingrowths. We investigated the genetic control of wall ingrowth formation in phloem parenchyma transfer cells of leaf minor veins in Arabidopsis thaliana. Wall ingrowth development in these cells is substantially enhanced upon exposing plants to high-light or cold treatments. A hierarchical bioinformatic analysis of public microarray datasets derived from the leaves of plants subjected to these treatments identified GIGANTEA (GI) as one of 46 genes that are commonly up-regulated twofold or more under both high-light and cold conditions. Histological analysis of the GI mutants gi-2 and gi-3 showed that the amount of phloem parenchyma containing wall ingrowths was reduced 15-fold compared with wild-type. Discrete papillate wall ingrowths were formed in gi-2 plants but failed to develop into branched networks. Wall ingrowth development in gi-2 was not rescued by exposing these plants to high-light or cold conditions. In contrast, over-expression of GI in the gi-2 background restored wall ingrowth deposition to wild-type levels. These results indicate that GI regulates the ongoing development of wall ingrowth networks at a point downstream of inputs from environmental signals.

Toxicity of xenobiotics during sulfate, iron, and nitrate reduction in primary sewage sludge suspensions

The effect and persistence of six organic xenobiotics was tested under sulfate-, iron-, and nitrate-reducing conditions in primary sewage sludge suspensions. The xenobiotics tested were acenaphthene, phenanthrene, di(2-ethylhexyl)phthalate (DEHP), 4-nonylphenol (4-NP), linear alkylbenzene sulfonate (LAS), and 1,2,4-trichlorobenzene (1,2,4-TCB) added to initial analytical concentrations of 54-117 mgL(-1). The suspensions were incubated at 30 degrees C for 15 weeks and rates of sulfate, iron, and nitrate reduction were estimated from the time course of hydrogen sulfide accumulation, Fe(II) accumulation, and nitrate depletion, respectively. Chemical analysis showed that the xenobiotics were persistent under the different electron acceptor regimes for the duration of the experiment. This was partly attributed to low bioavailability and microbial toxicity of the xenobiotics. Rates of anaerobic respiration in control suspensions (without added xenobiotics) showed a weekly reduction potential of 0.84 mM SO(4)(2-), 0.92 mM Fe(III), and 9.25 mM NO(3)(-). All three processes were completely inhibited by 1,2,4-TCB (54 mgL(-1)) whereas there was no significant (P<0.05) toxicity of phenanthrene (109 mgL(-1)) and DEHP (105 mgL(-1)). Sulfate reduction was inhibited completely by LAS (105 mgL(-1)), 76% by acenaphthene (54 mgL(-1)) and 57% by 4-NP (117 mgL(-1)), and likewise iron reduction was inhibited 62% by LAS and 55% by 4-NP (the latter though at P<0.10). Nitrate reduction was not significantly inhibited by acenaphthene and 4-NP and furthermore was resistant to LAS toxicity (105 mgL(-1)). Nitrate reduction also had the highest potential for mineralization of organic matter and thus was the most robust of the tested anaerobic processes in the sewage sludge suspensions.

Behaviour of different anaerobic populations on the biodegradation of textile chemicals

The anaerobic biodegradation of textile chemicals was evaluated with inocula grown under mesophilic (37+/-2 degrees C) or thermophilic (55+/-2 degrees C) conditions, on glucose (glucose-grown) or acetate (acetate-grown) as sole carbon sources. Wool dyebath chemicals (acetic acid, a liposomal surfactant, a synthetic amphoteric surfactant), single or as binary acetate-surfactant mixtures, were used as test carbon sources, in the presence or absence of Acid Orange 7 as model dye. First, the two mesophilic inocula (glucose- or acetate-grown) were compared relatively to lag-phase durations, specific biogas production rates, biogas yields and overall COD removal yields. In some runs, sulphide and/or the model dye were included, to test for inhibition effects. Then, the two glucose-grown inocula (mesophilic and thermophilic) were assessed in batch biodegradation tests with the same carbon feeds. The kinetics for substrate-COD and dye colour removal were described and quantified using a pseudo-first order model. The presence of dye had no effect on performance parameters for all substrates tested. Acetoclastic methanogens seemingly played an important role in biogas production from the liposomal additive, but less so from the synthetic surfactant. The association of acetate and surfactants apparently introduced mutual inhibitory effects on the rates of biogas production, substrate uptake and dye decolourisation.

4-Pregnen-21-ol-3,20-dione-21-(4-bromobenzenesulfonate) (NSC 88915) and related novel steroid derivatives as tyrosyl-DNA phosphodiesterase (Tdp1) inhibitors

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is an enzyme that catalyzes the hydrolysis of 3'-phosphotyrosyl bonds. Such linkages form in vivo when topoisomerase I (Top1) processes DNA. For this reason, Tdp1 has been implicated in the repair of irreversible Top1-DNA covalent complexes. Tdp1 inhibitors have been regarded as potential therapeutics in combination with Top1 inhibitors, such as the camptothecin derivatives, topotecan, and irinotecan, which are used to treat human cancers. Using a novel high-throughput screening assay, we have identified the C21-substituted progesterone derivative, NSC 88915 (1), as a potential Tdp1 inhibitor. Secondary screening and cross-reactivity studies with related DNA processing enzymes confirmed that compound 1 possesses specific Tdp1 inhibitory activity. Deconstruction of compound 1 into discrete functional groups reveals that both components are required for inhibition of Tdp1 activity. Moreover, the synthesis of analogues of compound 1 has provided insight into the structural requirements for the inhibition of Tdp1. Surface plasmon resonance shows that compound 1 binds to Tdp1, whereas an inactive analogue fails to interact with the enzyme. On the basis of molecular docking and mechanistic studies, we propose that these compounds are competitive inhibitors, which mimics the oligonucleotide-peptide Tdp1 substrate. These steroid derivatives represent a novel chemotype and provide a new scaffold for developing small molecule inhibitors of Tdp1.

Vesicles as soft templates for the enzymatic polymerization of aniline

The feasibility of using surfactant vesicles as soft templates for the peroxidase-triggered polymerization of aniline was investigated. It was found that mixed anionic vesicles (diameter approximately 80 nm) composed of sodium dodecylbenzenesulfonate (SDBS) and decanoic acid (1:1, molar ratio) are promising templates. In the presence of the vesicles and horseradish peroxidase/hydrogen peroxide (H2O2) as initiator system, aniline polymerizes under optimized conditions at pH=4.3 to the desired conductive emeraldine form of polyaniline (PANI). The optimal polymerization conditions were elaborated, and some of the chemical and physicochemical aspects of the reaction system were investigated. After addition of aniline and peroxidase to the vesicles, aniline is only loosely associated with the vesicles, as shown by NOESY-NMR and zeta potential measurements. In contrast, the peroxidase strongly binds to the vesicle surface, as shown by fluorescence measurements using TNS (2-(p-toluidino)naphthalene-6-sulfonate) as vesicle membrane probe. This binding of the enzyme to the vesicle surface indicates that the polymerization reaction is initiated predominantly on the surface of the vesicles. Cryo-transmission electron microscopy indicates that the polymerization product remains associated with the vesicles on their surface. For short reaction times (30 s<t<60 s), it is shown that oligoanilines containing an excess of oxidized units are obtained, as shown by VIS/NIR spectroscopy and MALDI-TOF mass spectrometry. For longer reaction times (1 min<t<30 min), the relative amount of over oxidized units in PANI decreases until polymers are obtained which have a VIS/NIR spectrum that is typical for the emeraldine salt form of PANI (lambdamax approximately 1000 nm). The appearance of stable unpaired electrons during the reaction was demonstrated by EPR measurements, in full support of the in situ formation of the conductive emeraldine salt form of PANI. At the end of the reaction (after 1 h), the PANI formed remains homogenously dispersed in the aqueous solution thanks to the presence of the vesicles. No precipitation occurs on a time scale of at least several weeks. FTIR and 13C NMR measurements of the product isolated from the reaction mixture confirm the formation of the emeraldine form of PANI. If the polymerization reaction is carried out in the absence of vesicles but under otherwise identical reaction conditions, the outcome of the reaction is very different, i.e., no indication at all for the formation of the conductive form of PANI.

[Detection of bensultap (bancol) derivatives and metabolites by chromatographic methods]

This paper is designed to describe methods for the detection of derivatives and metabolites of the insecticidic agent bancol (nereistoxin precursor) by chromatographic methods including thin layer chromatography (TLC), high-performance liquid chromatography (HPLC), gas chromatography with a nitrogen-phosphorous detector (GC-NPD), and gas chromatography mass spectrometry (GH-MS). The data obtained confirm the high diagnostic value of assays for derivatives and metabolites compared with the determination of the respective parent insecticides. New variants of extraction of these compounds from urine and various tissues by liquid-liquid and solid-phase chromatography are proposed. Their spectral and chromatographic characteristics are reported.

Degradation of Acid Orange 7 using magnetic AgBr under visible light: the roles of oxidizing species

AgBr was creatively immobilized on a magnetic substrate (SiO(2)-coated Fe(3)O(4) nanoparticle, SFN) to achieve magnetic separation after visible light-driven photocatalytic oxidation (PCO). The resulted Ag/AgBr/SFN was characterized by TEM, vibrating sample magnetometer and other techniques. It is found that the average diameter of the Ag/AgBr/SFN particle is less than 20 nm. The typical superparamagnetic behavior of Ag/AgBr/SFN implies that the catalyst can be magnetically separated. The physicochemical features of the used Ag/AgBr/SFN after visible light irradiation were not dramatically changed by X-ray diffraction, UV-Vis diffuse reflectance spectra and Fourier transform-infrared analysis. SiO(2) interlayer was proven to slightly increase the degradation efficiency for an azo dye Acid Orange 7. UV-Vis spectra and HPLC analysis indicated that the dye was oxidized and decomposed. The photoactivity of Ag/AgBr/SFN was partly maintained after successive PCO under visible light. In order to evaluate the roles of e(-)-h(+) pairs and reactive oxygen species, the quenching effect was examined by employing Ag/AgBr/SFN and commercial TiO(2) (P-25) under visible light (lambda>400 nm) and UV-A irradiation, respectively. Active h(+) and the resulting (*)OH played the major roles for degradation. The effect of active h(+) and (*)OH were proven to be highly dependent on the concentration of photocatalysts. The effect of (*)OH was more obvious for P-25, while that of active h(+) was more predominant for Ag/AgBr/SFN.

Detoxification of azo dyes by a novel pH-versatile, salt-resistant laccase from Streptomyces ipomoea

A newly identified extracellular laccase produced by Streptomyces ipomoea CECT 3341 (SilA) was cloned and overexpressed, and its physicochemical characteristics assessed together with its capability to decolorize and detoxify an azotype dye. Molecular analysis of the deduced sequence revealed that SilA contains a TAT-type signal peptide at the N-terminus and only two cupredoxine domains; this is consistent with reports describing two other Streptomyces laccases but contrasts with most laccases, which contain three cupredoxine domains. The heterologous expression and purification of SilA revealed that the homodimer is the only active form of the enzyme. Its stability at high pH and temperature, together with its resistance to high concentrations of NaCl and to typical laccase inhibitors such as sodium azide confirmed the unique properties of this novel laccase. The range of substrates that SilA is able to oxidize was found to be pH-dependent; at alkaline pH, SilA oxidized a wide range of phenolic compounds, including the syringyl and guayacil moieties derived from lignin. The oxidative potential of this enzyme to use phenolic compounds as natural redox mediators was shown through the coordinated action of SilA and acetosyringone (as mediator), which resulted in the complete detoxification of the azo-type dye Orange II.

Oxidative stress and histopathology damage related to the metabolism of dodecylbenzene sulfonate in Senegalese sole

Surfactants such as linear alkylbenzene sulfonates (LAS) are widely utilised in the formulation of detergents in commercial products. After use, they pass through waste water treatment plants (WWTP) and are then discharged to aquatic ecosystems, causing risk to aquatic life. The exposure of marine animals to these compounds enhances the production of reactive oxygen species (ROS) with subsequent damage to macromolecules, and produces histological alterations. A flow-through experiment with Senegalese sole (Solea senegalensis) has been devised with the object of correlating the metabolism of LAS including sulfophenylcarboxylic acids (SPCs) by fish with their antioxidant defence system (generation of oxyradicals) and histopathological damage. The generation of intermediate degradation products (SPCs) by the organism, the histopathological responses, the antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione S-transferase (GST)), as well as other kinds of enzyme such as acid and alkaline phosphatases (AcP, ALP), were measured. SPCs from 5ØC(6) to 11ØC(12) were identified and quantified in fish and water; their concentrations differed depending on the sampling moment. In general, the responses found in the enzymes were slight: a decrease in the enzymatic activity in gills and activation in the digestive tract. The evidence of histopathological damage identified was also small; the organism's defensive mechanism against pollutants should enable it to recover easily. A direct relationship was established between biotransformation and the generation of SPCs and ROS. In conclusion, the correct functioning of the antioxidant defence system with absence of large variations, the short-term histopathological damage, and the evidence of SPCs indicate an adequate metabolism of 2-phenyl-C(12)-linear alkylbenzene sulfonates (2ØC(12)LAS) by this specie and non-toxic effects at environmentally realistic levels.

Use of 4-sulfophenyl isothiocyanate labeling and mass spectrometry to determine the site of action of the streptococcolytic peptidoglycan hydrolase zoocin A

Zoocin A is a streptococcolytic peptidoglycan hydrolase with an unknown site of action that is produced by Streptococcus equi subsp. zooepidemicus 4881. Zoocin A has now been determined to be a d-alanyl-l-alanine endopeptidase by digesting susceptible peptidoglycan with a combination of mutanolysin and zoocin A, separating the resulting muropeptides by reverse-phase high-pressure liquid chromatography, and analyzing them by mass spectrometry (MS) in both the positive- and negative-ion modes to determine their compositions. In order to distinguish among possible structures for these muropeptides, they were N-terminally labeled with 4-sulfophenyl isothiocyanate (SPITC) and analyzed by tandem MS in the negative-ion mode. This novel application of SPITC labeling and MS/MS analysis can be used to analyze the structure of peptidoglycans and to determine the sites of action of other peptidoglycan hydrolases.

[The effect of mutations in the synthesis of lipopolysaccharides and calcofluor-binding polysaccharides on biofilm formation by Azospirillum brasilense]

The thickness and antigenic properties of biofilms produced by Azospirillum brasilense Sp245 and its mutants deficient in the synthesis of lipopolysaccharides (Lps) and calcofluor-binding polysaccharides (CBPS) at the interface between water and hydrophilic or hydrophobic solid surfaces were compared. The mutants deficient in acidic LpsI synthesis produce thicker biofilms on hydrophilic surfaces. Biofilms produced on hydrophobic surfaces by bacteria that are unable to synthesize CBPS are less pronounced. Defects in CBPS production in Azospirillum mutants with impaired flagellar motility can cause adverse effects on the cell ability to attach to hydrophobic and hydrophilic surfaces. The loss of the neutral LpsII antigen by the mutants capable of producing CBPS does not affect their behavior on hydrophobic surfaces, which is probably due to the compensatory increase in the total polysaccharide production. The fundamental change in the Lps structure correlates with the activation of biofilm formation by the relevant mutants on hydrophilic and hydrophobic surfaces.

Genome-wide analysis of membrane transport using yeast knockout arrays

The transport of membrane-bound proteins through post-Golgi compartments depends on the coordinated function of multiple genes that direct the recognition and routing of protein cargoes to their final cellular destination. As many of these sorting components are nonessential for viability, genome-wide screening of the yeast gene-deletion mutant collection provides a useful strategy for their identification. The potential of this approach is limited only by the availability of transport assays suitable for the high-throughput screening of yeast colony arrays. Two large-scale phenotypic screens to identify novel transport genes are described here. The fluorescence-based Calcofluor white assay identifies mutants with altered plasma membrane localization of the chitin synthase Chs3, which recycles between the cell surface, endosomes, and the late Golgi. The carboxypeptidase Y (CPY) assay allows mutants of a distinct Golgi-to-vacuole transport pathway to be identified, due to the missorting and secretion of the vacuolar hydrolase CPY from the cell.

Determination of bovine serum albumin using resonance light scattering technique with sodium dodecylbenzene sulphonate-cetyltrimethylammonium bromide probe

In this paper, the anionic surfactant sodium dodecylbenzene sulphonate (SDBS) and cationic surfactant cetyltrimethylammonium bromide (CTMAB) were used as resonance light scattering (RLS) probe to determine bovine serum albumin (BSA). Based on the weak RLS intensity of SDBS-CTMAB probe and the enhancement of RLS intensity of BSA in the presence of the probe, a simple assay for BSA was developed. The experimental results showed that the formation of three component complex BSA-SDBS-CTMAB is the main reason for the enhancement of RLS intensity of BSA, in which SDBS as a bridge can interact with both BSA and CTMAB. The effects of pH value, incubation time, concentrations of SDBS and CTMAB on the enhanced RLS intensity of BSA were investigated. Under the optimum conditions, the enhanced RLS intensity is proportional to the concentration of BSA in the range from 2.5 x 10(-8) to 2.0 x 10(-6)mol L(-1). The detection limit is 9.7 x 10(-9) mol L(-1) for BSA. The study of foreign substance effect on the determination of BSA indicated that most of metal ions have little effect on the determination of BSA. The results of assay for BSA in synthetic samples were satisfactory.

Histone deacetylase inhibitor MS-275 alone or combined with bortezomib or sorafenib exhibits strong antiproliferative action in human cholangiocarcinoma cells

AIM: To investigate the antiproliferative effect of the histone deacetylase (HDAC) inhibitor MS-275 on cholangiocarcinoma cells alone and in combination with conventional cytostatic drugs (gemcitabine or doxorubicin) or the novel anticancer agents sorafenib or bortezomib.

METHODS: Two human bile duct adenocarcinoma cell lines (EGI-1 and TFK-1) were studied. Crystal violet staining was used for detection of cell number changes. Cytotoxicity was determined by measuring the release of the cytoplasmic enzyme lactate dehydrogenase (LDH). Apoptosis was determined by measuring the enzyme activity of caspase-3. Cell cycle status reflected by the DNA content was detected by flow cytometry.

RESULTS: MS-275 treatment potently inhibited the proliferation of EGI-1 and TFK-1 cholangiocarcinoma cells by inducing apoptosis and cell cycle arrest. MS-275-induced apoptosis was characterized by activation of caspase-3, up-regulation of Bax and down-regulation of Bcl-2. Cell cycle was predominantly arrested at the G₁/S checkpoint, which was associated with induction of the cyclin-dependent kinase inhibitor p21^Waf/CIP1. Furthermore, additive anti-neoplastic effects were observed when MS-275 treatment was combined with gemcitabine or doxorubicin, while combination with the multi-kinase inhibitor sorafenib or the proteasome inhibitor bortezomib resulted in overadditive anti-neoplastic effects.

CONCLUSION: The growth of human cholangiocarcinoma cells can be potently inhibited by MS-275 alone or in combination with conventional cytostatic drugs or new, targeted anticancer agents.

4-sulfomuconolactone hydrolases from Hydrogenophaga intermedia S1 and Agrobacterium radiobacter S2

The 4-carboxymethylen-4-sulfo-but-2-en-olide (4-sulfomuconolactone) hydrolases from Hydrogenophaga intermedia strain S1 and Agrobacterium radiobacter strain S2 are part of a modified protocatechuate pathway responsible for the degradation of 4-sulfocatechol. In both strains, the hydrolase-encoding genes occur downstream of those encoding the enzymes that catalyze the lactonization of 3-sulfomuconate. The deduced amino acid sequences of the 4-sulfomuconolactone hydrolases demonstrated the highest degree of sequence identity to 2-pyrone-4,6-dicarboxylate hydrolases, which take part in the meta cleavage pathway of protocatechuate. The 4-sulfomuconolactone hydrolases did not convert 2-pyrone-4,6-dicarboxylate, and the 2-pyrone-4,6-dicarboxylate hydrolase from Sphingomonas paucimobilis SYK-6 did not convert 4-sulfomuconolactone. Nevertheless, the presence of highly conserved histidine residues in the 4-sulfomuconolactone and the 2-pyrone-4,6-dicarboxylate hydrolases and some further sequence similarities suggested that both enzymes belong to the metallo-dependent hydrolases (the "amidohydrolase superfamily"). The 4-sulfomuconolactone hydrolases were heterologously expressed as His-tagged enzyme variants. Gel filtration experiments suggested that the enzymes are present as monomers in solution, with molecular weights of approximately 33,000 to 35,000. 4-Sulfomuconolactone was converted by sulfomuconolactone hydrolases to stoichiometric amounts of maleylacetate and sulfite. The 4-sulfomuconolactone hydrolases from both strains showed pH optima at pH 7 to 7.5 and rather similar catalytic constant (k(cat)/K(M))values. The suggested 4-sulfocatechol pathway from 4-sulfocatechol to maleylacetate was confirmed by in situ nuclear magnetic resonance analysis using the recombinantly expressed enzymes.

Optimal conditions for visualizing water-conducting pathways in a living tree by the dye injection method

To elucidate the water-conducting pathways in living trees by the dye injection method, suitable sample preparation procedures are needed. We evaluated quantitatively the properties and concentrations of three dyes (acid fuchsin, basic fuchsin and safranin) widely used for this purpose, and determined the optimal conditions required to avoid artifacts after dye injection into the sap stream of Pieris japonica D. Don. Among the dyes tested, an aqueous solution of acid fuchsin at a concentration of 0.1% or more was the most useful for delineating water movement. In non-transpiring stem segments, the vertical movement of acid fuchsin by capillarity and diffusion from the dye injection site was limited. However, acid fuchsin moved rapidly in the horizontal direction by capillarity and diffusion, and most xylem cells were stained within 2 h. A delay of more than 2 h between dye injection and examination of the tissues greatly reduces the precision of the method. Use of the dye injection method without appropriate, well-defined experimental procedures may give rise to misleading information about the functional water-conducting pathway in living trees.

The (1,3)β-d-glucan synthase subunit Bgs1p is responsible for the fission yeast primary septum formation

Cytokinesis is a crucial event in the cell cycle of all living cells. In fungal cells, it requires co-ordinated contraction of an actomyosin ring and synthesis of both plasmatic membrane and a septum structure that will constitute the new cell wall end. Schizosaccharomyces pombe contains four essential putative (1,3)beta-d-glucan synthase catalytic subunits, Bgs1p to Bgs4p. Here we examined the function of Bgs1p in septation by studying the lethal phenotypes of bgs1(+) shut-off and bgs1Delta cells and demonstrated that Bgs1p is responsible and essential for linear (1,3)beta-d-glucan and primary septum formation. bgs1(+) shut-off generates a more than 300-fold Bgs1p reduction, but the septa still present large amounts of disorganized linear (1,3)beta-d-glucan and partial primary septa. Conversely, both structures are absent in bgs1Delta cells, where there is no Bgs1p. The septum analysis of bgs1(+)-repressed cells indicates that linear (1,3)beta-d-glucan is necessary but not sufficient for primary septum formation. Linear (1,3)beta-d-glucan is the polysaccharide that specifically interacts with the fluorochrome Calcofluor white in fission yeast. We also show that in the absence of Bgs1p abnormal septa are formed, but the cells cannot separate and eventually die.

Decolorization and partial degradation of monoazo dyes in sequential fixed-film anaerobic batch reactor (SFABR)

Decolorization of two monoazo dyes, acid orange 6 (AO6) and acid orange 7 (AO7), were studied in sequential fixed-film anaerobic batch reactor (SFABR) with varying dye concentrations and 500 mg/L glucose as the co-substrate. More than 90% dye decolorization could be achieved, even at 300 mg/L, with both AO6 and AO7 and dye decolorization rates were 168 mg/L/d and 176 mg/L/d, respectively. COD removals with these two monoazo dyes were significantly different, as 75% and 35% decrease were observed with AO6 and AO7, respectively. UV-visible spectral as well as HPLC analysis of SFABR treated effluent showed the accumulation of 4-aminobenzenesulfonate (4-ABS) from AO6 and AO7. Aminoresorcinol (AR) formed from AO6 decolorization could not be detected at the end of SFABR cycle. This along with high COD removal indicated its further degradation. Formation of pink coloration on exposure to air indicated the presence of 1-amino-2-naphthol (AN) in AO7 fed reactor effluent. Thus both 4-ABS and AN were resistant to further degradation under anaerobic conditions. Presence of nitrate did not decrease the observed decolorization at the end of 24h SFABR cycle, although initial rate was decreased. This indicates the suitability of SFABR configuration for the treatment of azo-dye containing wastewaters in the presence of nitrate.

Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: kinetics and biodegradability enhancement

Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15 bar of oxygen partial pressure (P(O2)) and at 180, 200 and 220 degrees C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and P(O2) were 140-160 degrees C and 2-9 bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160 degrees C and 2 bar of P(O2), which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (COD(RB)) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture.

Selective chemical probe inhibitor of Stat3, identified through structure-based virtual screening, induces antitumor activity

S3I-201 (NSC 74859) is a chemical probe inhibitor of Stat3 activity, which was identified from the National Cancer Institute chemical libraries by using structure-based virtual screening with a computer model of the Stat3 SH2 domain bound to its Stat3 phosphotyrosine peptide derived from the x-ray crystal structure of the Stat3beta homodimer. S3I-201 inhibits Stat3.Stat3 complex formation and Stat3 DNA-binding and transcriptional activities. Furthermore, S3I-201 inhibits growth and induces apoptosis preferentially in tumor cells that contain persistently activated Stat3. Constitutively dimerized and active Stat3C and Stat3 SH2 domain rescue tumor cells from S3I-201-induced apoptosis. Finally, S3I-201 inhibits the expression of the Stat3-regulated genes encoding cyclin D1, Bcl-xL, and survivin and inhibits the growth of human breast tumors in vivo. These findings strongly suggest that the antitumor activity of S3I-201 is mediated in part through inhibition of aberrant Stat3 activation and provide the proof-of-concept for the potential clinical use of Stat3 inhibitors such as S3I-201 in tumors harboring aberrant Stat3.

[Isolation and characterization of a sodium dodecyl benzene sulfonate degrading bacterial strain]

A bacterial strain, designated as WZR-A, which could utilize sodium dodecyl benzene sulfonate (SDBS) as sole carbon and energy source for growth, was isolated from contaminated river. The strain was identified as Ochrobactrum anthropi based on its morphological and physiological properties, and 16S rDNA sequence analysis. The optimum pH and temperature for cell growth and SDBS degradation were 7.0 and 30 degrees U, respectively. The degradation rate of SDBS by strain WZR-A was higher than 80% when its concentration was lower than 400mg/L. The results of whole cell protein SDS-PAGE electrophoresis showed that there were very obvious differences in the total cell protein composition of the strain between before and after SDBS induction. The enzyme distribution experiment showed that the enzymes relative SDBS degradation in the bacterium was intracellular one. Results from the characterization of degradation substrates together with the detection of activities of relative catabolic enzymes in crude extracts indicated that the aromatic ring cracking of SDBS by the strain probably via the modified ortho cleavage pathway and the strain could use broader spectrum substrates. A large plasmid was detected by utilizing plasmid isolating and curing technique and it was found that the genes involved in SDBS degradation were likely located on the plasmid.

Characterization of the genes encoding the 3-carboxy-cis,cis-muconate-lactonizing enzymes from the 4-sulfocatechol degradative pathways of Hydrogenophaga intermedia S1 and Agrobacterium radiobacter S2

Hydrogenophaga intermediastrain S1 andAgrobacterium radiobacterstrain S2 form a mixed bacterial culture which degrades sulfanilate (4-aminobenzenesulfonate) by a novel variation of theβ-ketoadipate pathway via 4-sulfocatechol and 3-sulfomuconate. It was previously proposed that the further metabolism of 3-sulfomuconate is catalysed by modified 3-carboxy-cis,cis-muconate-lactonizing enzymes (CMLEs) and that these ‘type 2’ enzymes were different from the conventional CMLEs (‘type 1’) from the protocatechuate pathway in their ability to convert 3-sulfomuconate in addition to 3-carboxy-cis,cis-muconate. In the present study the genes for two CMLEs (pcaB2S1andpcaB2S2) were cloned fromH. intermediaS1 andA. radiobacterS2, respectively. In both strains, these genes were located close to the previously identified genes encoding the 4-sulfocatechol-converting enzymes. The gene products ofpcaB2S1andpcaB2S2were therefore tentatively identified as type 2 enzymes involved in the metabolism of 3-sulfomuconate. The genes were functionally expressed and the gene products were shown to convert 3-carboxy-cis,cis-muconate and 3-sulfomuconate. 4-Carboxymethylene-4-sulfo-but-2-en-olide (4-sulfomuconolactone) was identified by HPLC-MS as the product, which was enzymically formed from 3-sulfomuconate. His-tagged variants of both CMLEs were purified and compared with the CMLE from the protocatechuate pathway ofPseudomonas putidaPRS2000 for the conversion of 3-carboxy-cis,cis-muconate and 3-sulfomuconate. The CMLEs from the 4-sulfocatechol pathway converted 3-sulfomuconate with considerably higher activities than 3-carboxy-cis,cis-muconate. Also the CMLE fromP. putidaconverted 3-sulfomuconate, but this enzyme demonstrated a clear preference for 3-carboxy-cis,cis-muconate as substrate. Thus it was demonstrated that in the 4-sulfocatechol pathway, distinct CMLEs are formed, which are specifically adapted for the preferred conversion of sulfonated substrates.

Cell suspension cultures of Populus tremula x P. tremuloides exhibit a high level of cellulose synthase gene expression that coincides with increased in vitro cellulose synthase activity

Compared to wood, cell suspension cultures provide convenient model systems to study many different cellular processes in plants. Here we have established cell suspension cultures of Populus tremula L. x P. tremuloides Michx. and characterized them by determining the enzymatic activities and/or mRNA expression levels of selected cell wall-specific proteins at the different stages of growth. While enzymes and proteins typically associated with primary cell wall synthesis and expansion were detected in the exponential growth phase of the cultures, the late stationary phase showed high expression of the secondary-cell-wall-associated cellulose synthase genes. Interestingly, detergent extracts of membranes from aging cell suspension cultures exhibited high levels of in vitro cellulose synthesis. The estimated ratio of cellulose to callose was as high as 50 : 50, as opposed to the ratio of 30 : 70 so far achieved with membrane preparations extracted from other systems. The increased cellulose synthase activity was also evidenced by higher levels of Calcofluor white binding in the cell material from the stationary-phase cultures. The ease of handling cell suspension cultures and the improved capacity for in vitro cellulose synthesis suggest that these cultures offer a new basis for studying the mechanism of cellulose biosynthesis.