Studies on bovine spleen cathepsin D

The purification procedure of cathepsin D which includes autolysis results in the destruction of the molecule to smaller polypeptide chains. Pure catepsin D obtained by the method which includes affinity chromatography, contains single polypeptide chain of 42000 daltons. The N-terminal amino acid is glycine. The specificity was studied using synthetic substrates. CD measurement of cathepsin D shows mainly unordered structure, about 26% of beta-structure and only 5% of alpha-helix. Binding of pepstatin shows pronounced changes in the CD spectrum between 250 and 300 nm; above 7.5 no interaction was observed.     

Rapid mapping of restriction sites of a DNA: restriction of agarose gel and two-dimensional analysis of end-labeled DNA.

A new two-dimensional technique for the mapping of restriction sites is presented. Linear DNA labeled at both ends is first partially digested with the restriction endonuclease for which a map is desired. Following electrophoresis of the partial digest in an agarose gel, complete digestion of the fragments in the gel matrix with a second restriction enzyme is carried out. Electrophoresis in the second dimension resolves two sets of labeled spots: one set from the left and the other from the right end. For a given band of the autoradiogram of the first dimension gel, the mobility of the band gives the size of the DNA fragment, and therefore the distance of a particular restriction site from one of the ends of the original linear DNA. The mobility of the labeled spot derived from this band in the second dimension gel allows one to distinguish whether the distance deduced above is from one end or the other. Additional information about the location of one set of restriction sites for one enzyme relative to those for a second enzyme can also be obtained using the two-dimensional method. The advantages of the technique are the small amount of DNA required and the rapidity with which many maps can be constructed from one labeled DNA. As a test of the method, maps for the HindIII and HaeIII cleavage sites of circular phage PM2 DNA have been obtained, after first converting the DNA to the linear form by digestion with HpaII.     

Ant genomics sheds light on the molecular regulation of social organization

Ants are powerful model systems for the study of cooperation and sociality. In this review, we discuss how recent advances in ant genomics have contributed to our understanding of the evolution and organization of insect societies at the molecular level.     

The Use of Molecular Analyses in Voided Urine for the Assessment of Patients with Hematuria

Introduction

Patients presenting with painless hematuria form a large part of the urological patient population. In many cases, especially in younger patients, the cause of hematuria is harmless. Nonetheless, hematuria could be a symptom of malignant disease and hence most patients will be subject to cystoscopy. In this study, we aimed to develop a prediction model based on methylation markers in combination with clinical variables, in order to stratify patients with high risk for bladder cancer.

Material and Methods

Patients (n=169) presenting with painless hematuria were included. 54 patients were diagnosed with bladder cancer. In the remaining 115 patients, the cause of hematuria was non-malignant. Urine samples were collected prior to cystoscopy. Urine DNA was analyzed for methylation of OSR1, SIM2, OTX1, MEIS1 and ONECUT2. Methylation percentages were calculated and were combined with clinical variables into a logistic regression model.

Results

Logistic regression analysis based on the five methylation markers, age, gender and type of hematuria resulted in an area under the curve (AUC) of 0.88 and an optimism corrected AUC of 0.84 after internal validation by bootstrapping. Using a cut-off value of 0.307 allowed stratification of patients in a low-risk and high-risk group, resulting in a sensitivity of 82% (44/54) and a specificity of 82% (94/115). Most aggressive tumors were found in patients in the high-risk group. The addition of cytology to the prediction model, improved the AUC from 0.88 to 0.89, with a sensitivity and specificity of 85% (39/46) and 87% (80/92), retrospectively.

Conclusions

This newly developed prediction model could be a helpful tool in risk stratification of patients presenting with painless hematuria. Accurate risk prediction might result in less extensive examination of low risk patients and thereby, reducing patient burden and costs. Further validation in a large prospective patient cohort is necessary to prove the true clinical value of this model.     

Attenuation of pattern recognition receptor signaling is mediated by a MAP kinase kinase kinase

Pattern recognition receptors (PRRs) play a key role in plant and animal innate immunity. PRR binding of their cognate ligand triggers a signaling network and activates an immune response. Activation of PRR signaling must be controlled prior to ligand binding to prevent spurious signaling and immune activation. Flagellin perception in Arabidopsis through FLAGELLIN‐SENSITIVE 2 (FLS2) induces the activation of mitogen‐activated protein kinases (MAPKs) and immunity. However, the precise molecular mechanism that connects activated FLS2 to downstream MAPK cascades remains unknown. Here, we report the identification of a differentially phosphorylated MAP kinase kinase kinase that also interacts with FLS2. Using targeted proteomics and functional analysis, we show that MKKK7 negatively regulates flagellin‐triggered signaling and basal immunity and this requires phosphorylation of MKKK7 on specific serine residues. MKKK7 attenuates MPK6 activity and defense gene expression. Moreover, MKKK7 suppresses the reactive oxygen species burst downstream of FLS2, suggesting that MKKK7‐mediated attenuation of FLS2 signaling occurs through direct modulation of the FLS2 complex.     

Akt activity negatively regulates phosphorylation of AMP-activated protein kinase in the heart

In the heart, insulin stimulates a variety of kinase cascades and controls glucose utilization. Because insulin is able to activate Akt and inactivate AMP-activated protein kinase (AMPK) in the heart, we hypothesized that Akt can regulate the activity of AMPK. To address the potential existence of this novel signaling pathway, we used a number of experimental protocols to activate Akt in cardiac myocytes and monitored the activation status of AMPK. Mouse hearts perfused in the presence of insulin demonstrated accelerated glycolysis and glucose oxidation rates as compared with non-insulin-perfused hearts. In addition, insulin caused an increase in Akt phosphorylation and a decrease in AMPK phosphorylation at its major regulatory site (threonine 172 of the alpha catalytic subunit). Transgenic mice overexpressing a constitutively active mutant form of Akt1 displayed decreased phosphorylation of cardiac alpha-AMPK. Isolated neonatal cardiac myocytes infected with an adenovirus expressing constitutively active mutant forms of either Akt1 or Akt2 also suppressed AMPK phosphorylation. However, Akt-dependent depression of alpha-AMPK phosphorylation could be overcome in the presence of the AMPK activator, metformin, suggesting that an override mechanism exists that can restore AMPK activity. Taken together, this study suggests that there is cross-talk between the AMPK and Akt pathways and that Akt activation can lead to decreased AMPK activity. In addition, our data suggest that the ability of insulin to inhibit AMPK may be controlled via an Akt-mediated mechanism.