Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses

This is the post-print version of the final paper published in Journal of Hazardous Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U–bacterial interaction experiments were performed at low pH values (2.0–4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase

Molecular Characterization and Expression of a Heat Shock Protein Gene (HSP90) from the Carmine Spider Mite, Tetranychus cinnabarinus (Boisduval)

In this study, the cDNA of Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae) HSP90 (designated TcHSP90) was cloned using a combination of the homology cloning and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of TcHSP90 is 2595 bp, including a 5′-untranslated region (UTR) of 177 bp, 3′-UTR of 249 bp, and an open reading frame (ORF) of 2169 bp. The ORF encodes a polypeptide of 722 amino acids with a predicted molecular weight of 83.45 kDa and a theoretical isoelectric point of 4.81. There is an mRNA polyadenylation signal of ATTAAA at the positions 2558–2564. In addition, the expression pattern of TcHSP90 mRNA relative to that of β-actin gene in the three stains of T. cinnabarinus (AbR, abamectin-resistant strain; HR, heat-resistant strain; SS, the susceptible strain) were examined by using fluorescent real time quantitative PCR after the impact of abamectin, high and low temperature, respectively. The results showed that under the normal condition, the mRNA level of TcHSP90 was 1.64 and 1.29-fold higher in the AbR and HR than in SS, respectively. After 8 h treatment with abamectin, the TcHSP90 mRNA levels of SS, AbR, and HR were 1.25, 1.87, and 2.05-fold higher than those of their untreated controls, respectively. The TcHSP90 mRNA levels of SS, AbR, and HR were also significantly increased after being induced at 40° C for 1 h, and they were 3.76, 3.42, and 3.79-fold higher than those of their untreated controls, respectively. The mRNA level of TcHSP90 was also significantly increased after being induced at 4° C for 1 h. These results suggest that TcHSP90 might be involved in the abamectin and extreme temperature resistance or tolerance

Yerli koyun ırklarında bulunan genetik çeşitlilik

TÜBİTAK TBAG01.12.2004Bu çalışmada, Türk koyun ırklarında mevcut genetik çeşitlilik 5 mikrosatelit lokusu kullanılarak incelenmiştir. Devlet üretim çiftlikleri, üniversite üretim çiftlikleri ve yerel yetiştiricilerin elinde bulunan sürülerden yerli ve melez onbir Türk ırkı (Akkaraman, Morkaraman, Kıvırcık, İvesi, Dağlıç, Karayaka, Hemşin, Norduz, Kangal, Konya Merinosu, Türkgeldi) ile bireyleri Irak'tan getirilmiş yabancı bir ırkı (Hamdani) temsil eden toplam 423 birey bu çalışmada kullanılmıştır. Bazı ırklar icin birden fazla örnekleme yapılmıştır. Genetik varyasyonun ölçütlerinden beklenen heterozigotluk (HE) 0.686 ile 0.793 arasında, ortalama gözlenen allel sayıları (OAS) ise 5.8 ile 11.8 arasında değişmiştir. Türkiye üzerinde allel frekans dağılımları, evcilleşme merkezlerinden olmuş olabilecek göçlerle beklenen, dogudan batıya geçişli bir değişim göstermemiştir. FST indeksi Akkaraman, Karayaka ve Dağlıç'ta aynı ırkın farklı örneklemelerindeki farklılaşmayı ölçmek için kullanılmıştır ve yetiştirme çiftliğinden alınan Akkarman1'in diğer iki Akkaraman populasyonundan istatistiki önemle (P<0.001) farklı olduğu bulunmuştur. FIS indeksi ile ırklar Hardy-Weinberg (H-W) dengesi açısından test edilmiş, Akkaraman1, İvesi, Morkaraman ve Hemşin'de H-W'den sapma tespit edilmiştir. AMOVA analizi toplam genetik varyasyonun büyük bir kısmının (~% 95) ırk içi bireyleri arasında olduğunu göstermiştir. Parallel sonuçlar ırk ve bireyleri arası genetik ilişkinin incelendiği faktöriyel benzerlik analizi ve allel paylaşım uzaklığı ile de elde edilmiş ve genellikle, ırklar arası belirgin bir fark görülmemiştir. DA genetik uzaklığı ile çizilen komşu birleştirme ağacı ve temel öğeler analizi ise ırklar ve çeşitli örnekleri arası farklılaşmayı incelemek için kullanılmıştır. Özellikle ilk analiz çiftlik örneklerinin farklı olduğunu göstermiştir. Delaunay ağı ırklar arasında 4 adet (ikisi coğrafi bariyer ile paralel) genetik sınır belirlemiştir. Sonuçların hepsi Kıvırcık ırkının diğerlerinden çok farklı olduğu yönündedir. Mantel testi ve Darboğaz testi istatistiksel olarak anlamlı bir sonuç ortaya koymamıştır. Avrupa ırklarının çoğuna genetik olarak en yakın bulunan Kıvırcık örneği olmuştur. Türk ırklarında Avrupa ırklarından yüksek fakat çok da farklı olmayan bir genetik çeşitlilik belirlenmiştir. Bunda son yıllarda koyun sayısında, Türkiye’de, yaşanan hızlı düşüş etkili olmuş olabileceği düşünülmüştür.In this study the genetic diversity in Turkish native sheep breeds was investigated based on fıve microsatellite loci. In total, 423 individuals from 11 native and crossbred Turkish sheep breeds (Akkaraman, Morkaraman, Kıvırcık, İvesi, Dağlıç, Karayaka, Hemşin, Norduz, Kangal, Konya Merinosu, Türkgeldi) and one Iraqi breed (Hamdani) were analyzed by sampling from breeding farms and local breeders. For some of the breeds sampling was done more than once. Genetic variation within breeds was estimated by expected heterozygosity (HE), which ranged between 0.686 and 0.793 and by the mean number of observed alleles (MNA), it ranged between 5.8 and 11.8. The allele frequency distribution across Turkey showed no gradient from east to west, gradient was expected in accordance with the migrations from the domestication centers. The differentiation between different samples of Akkaraman, Dağlıç and Karayaka breeds was tested by FST index. Akkaraman1 sample from the breeding farm was significantly (P<0.001) different from the other two Akkaraman samples. Deviation from Hardy-Weinberg expectations observed for Akkaraman1, İvesi, Morkaraman and Hemşin breeds. AMOVA analysis revealed that most of the total genetic variation (~95%) was within the individuals of the breeds. In parallel to this observation, when factorial correspondence analysis and shared alleles distances were used to analyze the relationship between the breeds and their individuals, generally, there were no clear discriminations between the breeds. Moreover, neighbour joining tree constructed based on DA genetic distance, and principle component analysis were used to analyze among breed differentiation. The former one emphasized the genetic distinctness of the farm samples. Delaunay network drew 4 genetic boundaries (two of them being parallel to geographic boundaries) between the breeds. All the results indicated that Kıvırcık was the most differentiated breed. Finally, Mantel Test and Bottleneck analysis did not reveal a significant result. Kıvırcık breed, among all native Turkish breeds, was found to be the genetically closest to the European breeds based on the loci analyzed. The genetic variation in Turkish breeds was not much higher than that of European breeds, which might be a consequence of the recent sharp decrease in sheep number, in Turkey

A Very Large Number of GABAergic Neurons Are Activated in the Tuberal Hypothalamus during Paradoxical (REM) Sleep Hypersomnia

We recently discovered, using Fos immunostaining, that the tuberal and mammillary hypothalamus contain a massive population of neurons specifically activated during paradoxical sleep (PS) hypersomnia. We further showed that some of the activated neurons of the tuberal hypothalamus express the melanin concentrating hormone (MCH) neuropeptide and that icv injection of MCH induces a strong increase in PS quantity. However, the chemical nature of the majority of the neurons activated during PS had not been characterized. To determine whether these neurons are GABAergic, we combined in situ hybridization of GAD67 mRNA with immunohistochemical detection of Fos in control, PS deprived and PS hypersomniac rats. We found that 74% of the very large population of Fos-labeled neurons located in the tuberal hypothalamus after PS hypersomnia were GAD-positive. We further demonstrated combining MCH immunohistochemistry and GAD67 in situ hybridization that 85% of the MCH neurons were also GAD-positive. Finally, based on the number of Fos-ir/GAD+, Fos-ir/MCH+, and GAD+/MCH+ double-labeled neurons counted from three sets of double-staining, we uncovered that around 80% of the large number of the Fos-ir/GAD+ neurons located in the tuberal hypothalamus after PS hypersomnia do not contain MCH. Based on these and previous results, we propose that the non-MCH Fos/GABAergic neuronal population could be involved in PS induction and maintenance while the Fos/MCH/GABAergic neurons could be involved in the homeostatic regulation of PS. Further investigations will be needed to corroborate this original hypothesis

Mistakes that affect others: An fMRI study on processing of own errors in a social context

In social contexts, errors have a special significance and often bear consequences for others. Thinking about others and drawing social inferences in interpersonal games engages the mentalizing system. We used neuroimaging to investigate the differences in brain activations between errors that affect only agents themselves and errors that additionally influence the payoffs of interaction partners. Activation in posterior medial frontal cortex (pMFC) and bilateral insula was increased for all errors, whereas errors that implied consequences for others specifically activated medial prefrontal cortex (mPFC), an important part of the mentalizing system. The results demonstrate that performance monitoring in social contexts involves additional processes and brain structures compared with individual performance monitoring where errors only have consequences for the person committing them. Taking into account how one’s behavior may affect others is particularly crucial for adapting behavior in interpersonal interactions and joint action

Group-regularized individual prediction: Theory and application to pain

Multivariate pattern analysis (MVPA) has become an important tool for identifying brain representations of psychological processes and clinical outcomes using fMRI and related methods. Such methods can be used to predict or ‘decode’ psychological states in individual subjects. Single-subject MVPA approaches, however, are limited by the amount and quality of individual-subject data. In spite of higher spatial resolution, predictive accuracy from single-subject data often does not exceed what can be accomplished using coarser, group-level maps, because single-subject patterns are trained on limited amounts of often-noisy data. Here, we present a method that combines population-level priors, in the form of biomarker patterns developed on prior samples, with single-subject MVPA maps to improve single-subject prediction. Theoretical results and simulations motivate a weighting based on the relative variances of biomarker-based prediction—based on population-level predictive maps from prior groups—and individual-subject, cross-validated prediction. Empirical results predicting pain using brain activity on a trial-by-trial basis (single-trial prediction) across 6 studies (N = 180 participants) confirm the theoretical predictions. Regularization based on a population-level biomarker—in this case, the Neurologic Pain Signature (NPS)—improved single-subject prediction accuracy compared with idiographic maps based on the individuals' data alone. The regularization scheme that we propose, which we term group-regularized individual prediction (GRIP), can be applied broadly to within-person MVPA-based prediction. We also show how GRIP can be used to evaluate data quality and provide benchmarks for the appropriateness of population-level maps like the NPS for a given individual or study.FSW – Publicaties zonder aanstelling Universiteit Leide

Enhanced Proliferation of Monolayer Cultures of Embryonic Stem (ES) Cell-Derived Cardiomyocytes Following Acute Loss of Retinoblastoma

Background: Cardiomyocyte (CM) cell cycle analysis has been impeded because of a reliance on primary neonatal cultures of poorly proliferating cells or chronic transgenic animal models with innate compensatory mechanisms. Methodology/Principal Findings: We describe an in vitro model consisting of monolayer cultures of highly proliferative embryonic stem (ES) cell-derived CM. Following induction with ascorbate and selection with puromycin, early CM cultures are.98 % pure, and at least 85 % of the cells actively proliferate. During the proliferative stage, cells express high levels of E2F3a, B-Myb and phosphorylated forms of retinoblastoma (Rb), but with continued cultivation, cells stop dividing and mature functionally. This developmental transition is characterized by a switch from slow skeletal to cardiac TnI, an increase in binucleation, cardiac calsequestrin and hypophosphorylated Rb, a decrease in E2F3, B-Myb and atrial natriuretic factor, and the establishment of a more negative resting membrane potential. Although previous publications suggested that Rb was not necessary for cell cycle control in heart, we find following acute knockdown of Rb that this factor actively regulates progression through the G1 checkpoint and that its loss promotes proliferation at the expense of CM maturation. Conclusions/Significance: We have established a unique model system for studying cardiac cell cycle progression, and show in contrast to previous reports that Rb actively regulates both cell cycle progression through the G1 checkpoint an

Joint action modulates motor system involvement during action observation in 3-year-olds

When we are engaged in a joint action, we need to integrate our partner’s actions with our own actions. Previous research has shown that in adults the involvement of one’s own motor system is enhanced during observation of an action partner as compared to during observation of an individual actor. The aim of this study was to investigate whether similar motor system involvement is present at early stages of joint action development and whether it is related to joint action performance. In an EEG experiment with 3-year-old children, we assessed the children’s brain activity and performance during a joint game with an adult experimenter. We used a simple button-pressing game in which the two players acted in turns. Power in the mu- and beta-frequency bands was compared when children were not actively moving but observing the experimenter’s actions when (1) they were engaged in the joint action game and (2) when they were not engaged. Enhanced motor involvement during action observation as indicated by attenuated sensorimotor mu- and beta-power was found when the 3-year-olds were engaged in the joint action. This enhanced motor activation during action observation was associated with better joint action performance. The findings suggest that already in early childhood the motor system is differentially activated during action observation depending on the involvement in a joint action. This motor system involvement might play an important role for children’s joint action performance