Characterization of the MTF-1 transcription factor from zebrafish and trout cells

Two Euphausia superba Dana endo-1.4-beta-xylanases (A, and B), hydrolysing xylan in the same manner as the enzyme classified as EC 3.2.1.8, were isolated and purified. (2) The enzymes were distinguished by their molecular mass and charge, affinities towards the oat xylan (Km of 4.1 and 7.7 mg ml(-1), respectively), values of activation energy in oat xylan hydrolysis (35.5 and 42.5 kJ mol(-1), respectively), as well as the way in which they split the substrate. (3) In vitro they showed the same optimal temperature (37-40 degrees C), optimal pH (5.7-6.0), very low thermostability, and were stabilized and activated by Ca2+ and Mg2+ ions, as well as by some unidentified substances with molecular mass less than 17 kDa, present in crude extracts of krill.     

Effects of Beta-Alanine Supplementation on Brain Homocarnosine/Carnosine Signal and Cognitive Function: An Exploratory Study

Objectives

Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d^-1 on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2).

Methods

In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion.

Results

In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P<0.05), although there was no effect (P>0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise.

Conclusion

28 d of beta-alanine supplementation at 6.4g d^-1 appeared not to influence brain homocarnosine/carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists.     

Post-operative small pelvic field radiation therapy in patients with intermediate risk early stage cervix cancer: a safe and efficient treatment modality

BackgroundThe treatment of early stage cervical cancer has different therapeutic options. Adjuvant external beam radiotherapy for surgically treated intermediate risk cervical cancer patients has shown acceptable oncological outcomes with a low incidence of toxicity. The aim of this study was to analyze the oncological outcomes and safety of adjuvant small pelvic field radiotherapy in surgically treated stage IB1-2 cervical cancer patients who met the Sedlis intermediate-risk criteria.Materials and methodsA retrospective cohort study was carried out with 28 patients treated from 2007 to November 2019 with biopsy proven intermediate risk stage IB1–2 cervical cancer previously treated with radical hysterectomy and bilateral lymphadenectomy who received adjuvant small pelvic field radiotherapy. The primary endpoints were local and distant control and overall survival. Secondary endpoints were acute and late gastrointestinal and genitourinary toxicity. Survival curves were analyzed using the Kaplan-Meier method.ResultsAfter a median follow up period of 41.5 (27.5–80.5) months, adjuvant small pelvic field radiotherapy showed a 100% overall survival rate, 81.82% disease free survival and 86.36% local recurrence-free survival with no incidence of grade 3 or 4 acute or late toxicity. Three patients suffered from relapse, 1 in the vaginal cuff, 1 in the retrovesical area and 1 patient in the retroperitoneal area.ConclusionsAdjuvant small pelvic field radiotherapy is an efficient and safe treatment option that offers excellent oncological outcomes to surgically treated intermediate-risk stage IB1–2 cervical cancer patients with an excellent toxicity profile.     

Information‐theoretic analysis of the reference state in contact potentials used for protein structure prediction

Using information‐theoretic concepts, we examine the role of the reference state, a crucial component of empirical potential functions, in protein fold recognition. We derive an information‐based connection between the probability distribution functions of the reference state and those that characterize the decoy set used in threading. In examining commonly used contact reference states, we find that the quasi‐chemical approximation is informatically superior to other variant models designed to include characteristics of real protein chains, such as finite length and variable amino acid composition from protein to protein. We observe that in these variant models, the total divergence, the operative function that quantifies discrimination, decreases along with threading performance. We find that any amount of nativeness encoded in the reference state model does not significantly improve threading performance. A promising avenue for the development of better potentials is suggested by our information‐theoretic analysis of the action of contact potentials on individual protein sequences. Our results show that contact potentials perform better when the compositional properties of the data set used to derive the score function probabilities are similar to the properties of the sequence of interest. Results also suggest to use only sequences of similar composition in deriving contact potentials, to tailor the contact potential specifically for a test sequence. Proteins 2010. © 2009 Wiley‐Liss, Inc.     

Inhibitory effect of a defensin gene from the Andean crop maca (Lepidium meyenii) against Phytophthora infestans

In this study, we report the isolation of a defensin gene, lm-def, isolated from the Andean crop 'maca' (Lepidium meyenii) with activity against the pathogen Phytophthora infestans responsible of late blight disease of the potato and tomato crops. The lm-def gene has been isolated by polymerase chain reaction (PCR) using degenerate primers corresponding to conserved regions of 13 plant defensin genes of the Brassicaceae family assuming that defensin genes are highly conserved among cruciferous species. The lm-def gene belongs to a small multigene family of at least 10 members possibly including pseudogenes as assessed by genomic hybridization and nucleotide sequence analyses. The deduced mature Lm-Def peptide is 51 amino acids in length and has 74-94% sequence identity with other plant defensins of the Brassicaceae family. The Lm-Def peptide was produced as a fusion protein using the pET-44a expression vector and purified using an immobilized metal ion affinity chromatography. The recombinant protein (NusA:Lm-Def) exhibited in vitro activity against P. infestans. The NusA:Lm-Def protein caused growth inhibition and hyphal damage at concentration not greater than 0.4 microM. In contrast, the NusA protein alone expressed and purified similarly did not show any activity against P. infestans. Therefore, these results indicate that the lm-def gene isolated from maca belong to the plant defensin family with activity against P. infestans. Its expression in potato, as a transgene, might help to control the late blight disease caused by P. infestans with the advantage of being of plant origin.     

Oryza sativa rice plants contain molecules that activate different quorum-sensing N-acyl homoserine lactone biosensors and are sensitive to the specific AiiA lactonase

Gram-negative bacteria most often use N-acyl homoserine lactones (AHLs) as intercellular quorum-sensing signal molecules. In this study, it was demonstrated that rice plants contain AHL mimic molecules that are very sensitive to the highly specific AiiA lactonase enzyme and can activate three different AHL bacterial biosensors, indicating that the compounds have a homoserine lactone structure and could be AHLs. The possible source and biological significance of this finding are discussed.     

Property-based sequence representations do not adequately encode local protein folding information

We examine the informatic characteristics of amino acid representations based on physical properties. We demonstrate that sequences rewritten using contracted alphabets based on physical properties do not encode local folding information well. The best four-character alphabet can only encode approximately 57% of the maximum possible amount of structural information. This result suggests that property-based representations that operate on a local length scale are not likely to be useful in homology searches and fold-recognition exercises.     

A preferred AMPK phosphorylation site adjacent to the inhibitory loop of cardiac and skeletal troponin I

5'-AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase that is activated when cellular AMP to ATP ratios rise, potentially serving as a key regulator of cellular energetics. Among the known targets of AMPK are catabolic and anabolic enzymes, but little is known about the ability of this kinase to phosphorylate myofilament proteins and thereby regulating the contractile apparatus of striated muscles. Here, we demonstrate that troponin I isoforms of cardiac (cTnI) and fast skeletal (fsTnI) muscles are readily phosphorylated by AMPK. For cTnI, two highly conserved serine residues were identified as AMPK sites using a combination of high-resolution top-down electron capture dissociation mass spectrometry, (32) P-incorporation, synthetic peptides, phospho-specific antibodies, and site-directed mutagenesis. These AMPK sites in cTnI were Ser149 adjacent to the inhibitory loop and Ser22 in the cardiac-specific N-terminal extension, at the level of cTnI peptides, the intact cTnI subunit, whole cardiac troponin complexes and skinned cardiomyocytes. Phosphorylation time-course experiments revealed that Ser149 was the preferred site, because it was phosphorylated 12-16-fold faster than Ser22 in cTnI. Ser117 in fsTnI, analogous to Ser149 in cTnI, was phosphorylated with similar kinetics as cTnI Ser149. Hence, the master energy-sensing protein AMPK emerges as a possibly important regulator of cardiac and skeletal contractility via phosphorylation of a preferred site adjacent to the inhibitory loop of the thin filament protein TnI.