[Characterization of a malic enzyme isoform V from Mucor circinelloides]

OBJECTIVE

We aimed at characterizing a malic enzyme isoform V from Mucor circinelloides.

METHODS

me1 gene encoding malic enzyme isoform V was amplified and cloned into expression vector pET28a. High-purity recombinant protein BLME1 was obtained by affinity chromatography using. Ni-NTA column and characterized subsequently.

RESULTS

The optimum conditions were pH at 8.0 and temperature at 33 degrees C. Under optimum conditions, BLME1 activity achieved 92.8 U/mg. The K(m) for L-malate and NADP+ were 0.74960 ± 0.06120 mmol/L and 0.22070 ± 0.01810 mmol/L, the V(max) for L-malate and NADP+ were 72.820 ± 1.077 U/mg and 86.110 ± 1.665 U/mg, respectively. In addition, ions played important roles in BLME1 activity; several ions such as Mn2+, Mg2+, Co2+, Ni2+ could activate BLME1, whereas Ca2+, Cu2+ could be used as inhibitors. Additionally, the metabolic intermediates such as oxaloacetic acid and α-ketoglutaric acid inhibited the activity of BLME1, whereas succinic acid activated it.

CONCLUSION

A malic enzyme isoform V from Mucor circinelloides was characterized, providing the references for further studies on this enzyme.

Serum carcinogenic antigen (CA)-125 and CA 19-9 combining pain score in the diagnosis of pelvic endometriosis in infertile women

OBJECTIVE

To define the utility of serum carcinogenic antigen (CA)-125 and CA 19-9 combining pain score in the prediction of pelvic endometriosis in infertile women.

MATERIALS AND METHODS

Serum CA-125 and CA 19-9 were measured using immunoradiologic methods during the follicular phase preceding laparoscopy for infertility. Values obtained were correlated with the occurrence and severity of endometriosis. Receiver operating characteristic (ROC) curve was applied to assess the utility of serum CA-125, CA 19-9, and pain score in preoperative preparation. Cut-off value of CA-125 and CA 19-9 was defined.

RESULTS

The study enrolled 294 infertile women receiving laparoscopy between July 2010 and September 2011. Ninety-four patients were diagnosed with endometriosis and 200 patients without. Preoperative serum CA-125 and CA 19-9 levels were significantly different between the two groups. ROC curve analyses of serum CA-125 and CA 19-9 set a cut-off value of 18.25 IU/ml and 13.15 IU/ml, producing a sensitivity of 64.8% and 84.8%, a specificity of 81.9% and 51.6%, a positive predictive value (PPV) of 63.6% and 46.1%, and a negative predictive value (NPV) of 81.0% and 87.4%, respectively. Combined-analyses of CA-125 and CA 19-9 produced a sensitivity of 72.4%, a specificity of 81.9%, a PPV of 62.3%, and a NPV of 81.8%. Combined-analyses of serum CA-125, CA 19-9 and pain score produced a sensitivity of 71.0% and a specificity of 74.0%.

CONCLUSIONS

Preoperative CA-125 and CA 19-9 levels combining pain score can be useful for the prediction of pelvic endometrinsis and may he included in the evaluation of unexulained infertile women.

Bioinformatical analysis and preliminary study of the role of lipase in lipid metabolism in Mucor circinelloides

The filamentous fungusMucor circinelloideshas been widely used as a model organism to investigate the mechanisms of lipid accumulation.

The role of a xylose isomerase pathway in the conversion of xylose to lipid in Mucor circinelloides

The xylose isomerase (XI) pathway, which converts xylose in lignocellulosic materials into intermediate metabolites, is characterized for the first time in M. circinelloides.

Interactions between carbon species and β-spodumene by first principles calculation

The appearance of Li–C compounds will strengthen the binding properties between carbon species and β-spodumene matrix.

MicroRNA-138 regulates chemoresistance in human non-small cell lung cancer via epithelial mesenchymal transition

OBJECTIVE

Down-regulation of miR-138 is observed in a variety of cancers, which suggests that miR-138 may be involved in cancer pathogenesis. Our current work aimed to evaluate the effects of miR-138 in adriamycin (ADM)-resistant human NSCLC cells.

MATERIALS AND METHODS

Cell proliferation was determined by MTT assay. Real-time PCR and western blot were performed to detect the mRNA and protein expression levels. The target of miR-138 was validated by luciferase activity assay.

RESULTS

Compared with the chemosensitive parental cells, miR-138 was remarkably decreased in A549/ADM and NCI-H23/ADM cells. Ectopic expression of miR-138 sensitized chemoresistant tumor cells to ADM administration. In addition, the epithelial-mesenchymal transition (EMT) related markers E-cadherin or vimentin was up-regulated or down-regulated upon the overexpression of miR-138 in NSCLC cells. Further studies identified zinc finger E-box-binding homeobox 2 (ZEB2) as the target of miR-138 and up-regulation of miR-138 suppressed the mRNA and protein expression of ZEB2. Notably, luciferase reporter assay confirmed that ZEB2 was a direct target of miR-138.

CONCLUSIONS

Our study demonstrates that miR-138 sensitizes NSCLC cells to ADM via EMT, suggesting that miR-138 might be a potential therapeutic target for drug-resistant NSCLC patients.

Adsorption dynamics and rate assessment of volatile organic compounds in active carbon

A new form of the pseudo-second-order kinetic model in terms of the adsorbed rate parameter and the THz parameter.

The role of middle calyx puncture in percutaneous nephrolithotomy: relative factors and choice considerations

Percutaneous nephrolithotomy (PCNL) is a well established procedure for management of renal calculi. It is generally believed that the access to the renal pelvic system via the desired calyx is the most crucial step during the whole procedure. The adequacy of the access directly influences the success and complication rates of PCNL. Traditionally, a lower pole access was routinely performed for less complication. Upper calices are also preferred for access in a given condition with large and complex calculi. However, the middle calices access is seldom selected. In aim to provide the reader some advantages of middle pole approach and a broaden horizon in determining the strategy of renal puncture, the present review describes the anatomical basis of the percutaneous tract. It provides a literature review of the success rate and efficiency of middle calyx access alone with the advantage of this approach, especially in dealing with large and complex stones.

(13)C-metabolic flux analysis of lipid accumulation in the oleaginous fungus Mucor circinelloides

The oleaginous fungus Mucor circinelloides is of industrial interest because it can produce high levels of polyunsaturated fatty acid γ-linolenic acid. M. circinelloides CBS 277.49 is able to accumulate less than 15% of cell dry weight as lipids, while M. circinelloides WJ11 can accumulate lipid up to 36%. In order to better understand the mechanisms behind the differential lipid accumulation in these two strains, tracer experiments with (13)C-glucose were performed with the growth of M. circinelloides and subsequent gas chromatography-mass spectrometric detection of (13)C-patterns in proteinogenic amino acids was carried out to identify the metabolic network topology and estimate intracellular fluxes. Our results showed that the high oleaginous strain WJ11 had higher flux of pentose phosphate pathway and malic enzyme, lower flux in tricarboxylic acid cycle, higher flux in glyoxylate cycle and ATP: citrate lyase, together, it might provide more NADPH and substrate acetyl-CoA for fatty acid synthesis.

Morphological and structural plasticity of grassland species in response to a gradient in saline-sodic soils

The abundance and distribution of species can be ascribed to both environmental heterogeneity and stress tolerance, with the latter measure sometimes associated with phenotypic plasticity. Although phenotypic plasticity varies predictably in response to common forms of stress, we lack a mechanistic understanding of the response of species to high saline-sodic soils. We compared the phenotypic plasticity of three pairs of high and low saline-sodic tolerant congeners from the families Poaceae (Leymus chinensis versus L. secalinus), Fabaceae (Lespedeza davurica versus L. bicolor) and Asteraceae (Artemisia mongolica versus A. sieversiana) in a controlled pot experiment in the Songnen grassland, China. The low tolerant species, L. secalinus and A. sieversiana exhibited higher plasticity in response to soil salinity and sodicity than their paired congeners. Highly tolerant species, L. chinensis and A. mongolica, had higher values for several important morphological traits, such as shoot length and total biomass under the high saline-sodic soil treatment than their paired congeners. In contrast, congeners from the family Fabaceae, L. davurica and L. bicolor, did not exhibit significantly different plasticity in response to soil salinity and sodicity. All species held a constant reproductive effort in response to saline-sodic soil stress. The different responses between low and high tolerant species offer an explanation for the distribution patterns of these species in the Songnen grassland. Highly tolerant species showed less morphological plasticity over a range of saline-sodic conditions than their paired congeners, which may manifest as an inability to compete with co-occurring species in locations where saline-sodic soils are absent.

Molecular mechanism of substrate specificity for delta 6 desaturase from Mortierella alpina and Micromonas pusilla

The ω6 and ω3 pathways are two major pathways in the biosynthesis of PUFAs. In both of these, delta 6 desaturase (FADS6) is a key bifunctional enzyme desaturating linoleic acid or α-linolenic acid. Microbial species have different propensity for accumulating ω6- or ω3-series PUFAs, which may be determined by the substrate preference of FADS6 enzyme. In the present study, we analyzed the molecular mechanism of FADS6 substrate specificity. FADS6 cDNAs were cloned from Mortierella alpina (ATCC 32222) and Micromonas pusilla (CCMP1545) that synthesized high levels of arachidonic acid and EPA, respectively. M. alpina FADS6 (MaFADS6-I) showed substrate preference for LA; whereas, M. pusilla FADS6 (MpFADS6) preferred ALA. To understand the structural basis of substrate specificity, MaFADS6-I and MpFADS6 sequences were divided into five sections and a domain swapping approach was used to examine the role of each section in substrate preference. Our results showed that sequences between the histidine boxes I and II played a pivotal role in substrate preference. Based on our domain swapping results, nine amino acid (aa) residues were targeted for further analysis by site-directed mutagenesis. G194L, E222S, M227K, and V399I/I400E substitutions interfered with substrate recognition, which suggests that the corresponding aa residues play an important role in this process.

The Cardioprotective Effects of Late-Phase Remote Preconditioning of Trauma Depends on Neurogenic Pathways and the Activation of PKC and NF-κB (But Not iNOS) in Mice

BACKGROUND

A superficial abdominal surgical incision elicits cardioprotection against cardiac ischemia-reperfusion (I/R) injury in mice. This process, called remote preconditioning of trauma (RPCT), has both an early and a late phase. Previous investigations have demonstrated that early RPCT reduces cardiac infarct size by 80% to 85%. We evaluated the cardioprotective and molecular mechanisms of late-phase RPCT in a murine I/R injury model.

METHODS

Wild-type mice, bradykinin (BK) 2 receptor knockout mice, 3M transgenic mice (nuclear factor κB [NF-κb] repressor inhibitor of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha [IκBα((S32A, S36A, Y42F))]), and inducible nitric oxide synthase (iNOS) knockout mice were analyzed using a previously established I/R injury model. A noninvasive abdominal surgical incision was made 24 hours prior to I/R injury and the infarct size was determined at 24 hours post-I/R injury.

RESULTS

The results indicated that a strong cardioprotective effect occurred during late-phase RPCT (58.42% ± 1.89% sham vs 29.41% ± 4.00% late RPCT, mean area of the infarct divided by the mean area of the risk region; P ≤ .05; n = 10). Furthermore, pharmacological intervention revealed the involvement of neurogenic signaling in the beneficial effects of late RPCT via sensory and sympathetic thoracic nerves. Pharmacological experiments in transgenic mice-implicated BK receptors, β-adrenergic receptors, protein kinase C, and NF-κB but not iNOS signaling in the cardioprotective effects of late RPCT.

CONCLUSION

Late RPCT significantly decreased myocardial infarct size via neurogenic transmission and various other signaling pathways. This protective mechanism differentiates late and early RPCT. This study describes a new cardiac I/R injury prevention method and refines the concept of RPCT.

Oscillatory cellular patterns in three-dimensional directional solidification

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in microgravity. Directional solidification experiments conducted onboard the International Space Station have allowed us to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 min. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelated at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (i.e., low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exists, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both three-dimensional experiments and simulations from realistic noisy initial conditions. In the latter case, erratic tip-splitting events promoted by large-amplitude oscillations contribute to maintaining the long-range array disorder, unlike in thin-sample experiments where long-range coherence of oscillations is experimentally observable.