Actinoplanes teichomyceticus ATCC 31121 as a cell factory for producing teicoplanin

Background

Single-domain antibody fragments possess structural features, such as a small dimension, an elevated stability, and the singularity of recognizing epitopes non-accessible for conventional antibodies that make them interesting for several research and biotechnological applications.

Results

The discovery of the single-domain antibody's potentials has stimulated their use in an increasing variety of fields. The rapid accumulation of articles describing new applications and further developments of established approaches has made it, therefore, necessary to update the previous reviews with a new and more complete summary of the topic.

Conclusions

Beside the necessary task of updating, this work analyses in detail some applicative aspects of the single-domain antibodies that have been overseen in the past, such as their efficacy in affinity chromatography, as co-crystallization chaperones, protein aggregation controllers, enzyme activity tuners, and the specificities of the unconventional single-domain fragments.     

Combinatorial analysis and algorithms for quasispecies reconstruction using next-generation sequencing

Background  

Next-generation sequencing (NGS) offers a unique opportunity for high-throughput genomics and has potential to replace Sanger sequencing in many fields, including de-novo sequencing, re-sequencing, meta-genomics, and characterisation of infectious pathogens, such as viral quasispecies. Although methodologies and software for whole genome assembly and genome variation analysis have been developed and refined for NGS data, reconstructing a viral quasispecies using NGS data remains a challenge. This application would be useful for analysing intra-host evolutionary pathways in relation to immune responses and antiretroviral therapy exposures. Here we introduce a set of formulae for the combinatorial analysis of a quasispecies, given a NGS re-sequencing experiment and an algorithm for quasispecies reconstruction. We require that sequenced fragments are aligned against a reference genome, and that the reference genome is partitioned into a set of sliding windows (amplicons). The reconstruction algorithm is based on combinations of multinomial distributions and is designed to minimise the reconstruction of false variants, called in-silico recombinants.     

Prior parity positively regulates learning and memory in young and middle-aged rats

Reproductive experience in female rats modifies acquired behaviors, induces long-lasting functional neuroadaptations and can also modify spatial learning and memory. The present study supports and expands this knowledge base by employing the Morris water maze, which measures spatial memory. Age-matched young adult (YNG) nulliparous (NULL; nonmated) and primiparous (PRIM; one pregnancy and lactation) female rats were tested 15 d after the litter's weaning. In addition, corresponding middle-aged (AGD) PRIM (mated in young adulthood so that pregnancy, parturition, and lactation occurred at the same age as in YNG PRIM) and NULL female rats were tested at 18 mo of age. Behavioral evaluation included: 1) acquisition of reference memory (platform location was fixed for 14 to 19 d of testing); 2) retrieval of this information associated with extinction of the acquired response (probe test involving removal of the platform 24 h after the last training session); and 3) performance in a working memory version of the task (platform presented in a novel location every day for 13 d, and maintained in a fixed location within each day). YNG PRIM outperformed NULL rats and showed different behavioral strategies. These results may be related to changes in locomotor, mnemonic, and cognitive processes. In addition, YNG PRIM exhibited less anxiety-like behavior. Compared with YNG rats, AGD rats showed less behavioral flexibility but stronger memory consolidation. These data, which were obtained by using a well-documented spatial task, demonstrate long lasting modifications of behavioral strategies in both YNG and AGD rats associated with a single reproductive experience.     

TGR5 activation inhibits atherosclerosis by reducing macrophage inflammation and lipid loading

The G protein-coupled receptor TGR5 has been identified as an important component of the bile acid signaling network, and its activation has been linked to enhanced energy expenditure and improved glycemic control. Here, we demonstrate that activation of TGR5 in macrophages by 6α-ethyl-23(S)-methylcholic acid (6-EMCA, INT-777), a semisynthetic BA, inhibits proinflammatory cytokine production, an effect mediated by TGR5-induced cAMP signaling and subsequent NF-κB inhibition. TGR5 activation attenuated atherosclerosis in Ldlr^−/−Tgr5^+/+ mice but not in Ldlr^−/−Tgr5^−/− double-knockout mice. The inhibition of lesion formation was associated with decreased intraplaque inflammation and less plaque macrophage content. Furthermore, Ldlr^−/− animals transplanted with Tgr5^−/− bone marrow did not show an inhibition of atherosclerosis by INT-777, further establishing an important role of leukocytes in INT-777-mediated inhibition of vascular lesion formation. Taken together, these data attribute a significant immune modulating function to TGR5 activation in the prevention of atherosclerosis, an important facet of the metabolic syndrome.     

Leviserpin: A Serine Peptidase Inhibitor (Serpin) from the Sugarcane Weevil <Emphasis Type="Italic">Sphenophorus levis</Emphasis>

Serine peptidase inhibitors (serpins) form a superfamily of proteins covering abroad spectrum of different biological functions. Here we describe the inhibitory characterization of leviserpin, the first serpin from the sugar cane weevil Sphenophorus levis. Leviserpin was able to inhibit bovine trypsin by the formation of the covalent complex serpin-peptidase, demonstrated by SDS–PAGE and mass spectroscopy analysis. We also have determined the cleavage site at the reactive center loop, by the analysis of the polypeptides released from de C-terminus of leviserpin. Moreover we investigated the mRNA expression of leviserpin in different stages of S. levis development. Thus the specificity of leviserpin, in addition with its mRNA coding being transcribed through all lifecycle of the insect, can suggest a possible role in defense mechanism by regulating the action of prophenoloxidase (proPO) activating enzyme.     

Automatic network fingerprinting through single-node motifs

Complex networks have been characterised by their specific connectivity patterns (network motifs), but their building blocks can also be identified and described by node-motifs-a combination of local network features. One technique to identify single node-motifs has been presented by Costa et al. (L. D. F. Costa, F. A. Rodrigues, C. C. Hilgetag, and M. Kaiser, Europhys. Lett., 87, 1, 2009). Here, we first suggest improvements to the method including how its parameters can be determined automatically. Such automatic routines make high-throughput studies of many networks feasible. Second, the new routines are validated in different network-series. Third, we provide an example of how the method can be used to analyse network time-series. In conclusion, we provide a robust method for systematically discovering and classifying characteristic nodes of a network. In contrast to classical motif analysis, our approach can identify individual components (here: nodes) that are specific to a network. Such special nodes, as hubs before, might be found to play critical roles in real-world networks.     

Neuropsychological profile in a large group of heart transplant candidates

Background

Recent studies have reported that patients with end-stage heart disease can have cognitive deficits ranging from mild to severe. Little is known, however, about the relationship between cognitive performance, neurophysiological characteristics and relevant clinical and instrumental indexes for an extensive evaluation of patients with heart failure, such as: left ventricular ejection fraction (LVEF) and other haemodynamic measures, maximum oxygen uptake during cardiopulmonary exercise testing, comorbidities, major cardiovascular risk factors and disease duration. Our purpose was to outline the cognitive profiles of end-stage heart disease patients in order to identify the cognitive deficits that could compromise the quality of life and the therapeutic adherence in end-stage heart disease patients, and to identify the variables associated with an increased risk of cognitive deficits in these patients.

Methods

207 patients with end-stage cardiac disease, candidates for heart transplant, were assessed by complete neuropsychological evaluation and by electroencephalographic recording with EEG spectral analysis.

Results

Pathological scores in one or more of the cognitive tests were obtained by 86% of the patients, while 36% performed within the impaired range on five or more tests, indicating poor performance across a broad range of cognitive domains. The executive functions were the cognitive domain most impaired (70%). Poor performances were not related to the aetiology of heart disease, but rather to cerebral dysfunction secondary to haemodynamic impairment and to comorbidities.

Conclusions

Severe heart failure induces significant neurophysiological and neuropsychological alterations, which may produce an impairment of cognitive functioning and possibly compromise the quality of life of patients and the therapeutic adherence.     

Electromyographic activity of hand muscles in a motor coordination game: effect of incentive scheme and its relation with social capital

Background

A vast body of social and cognitive psychology studies in humans reports evidence that external rewards, typically monetary ones, undermine intrinsic motivation. These findings challenge the standard selfish-rationality assumption at the core of economic reasoning. In the present work we aimed at investigating whether the different modulation of a given monetary reward automatically and unconsciously affects effort and performance of participants involved in a game devoid of visual and verbal interaction and without any perspective-taking activity.

Methodology/Principal Findings

Twelve pairs of participants were submitted to a simple motor coordination game while recording the electromyographic activity of First Dorsal Interosseus (FDI), the muscle mainly involved in the task. EMG data show a clear effect of alternative rewards strategies on subjects'' motor behavior. Moreover, participants'' stock of relevant past social experiences, measured by a specifically designed questionnaire, was significantly correlated with EMG activity, showing that only low social capital subjects responded to monetary incentives consistently with a standard rationality prediction.

Conclusions/Significance

Our findings show that the effect of extrinsic motivations on performance may arise outside social contexts involving complex cognitive processes due to conscious perspective-taking activity. More importantly, the peculiar performance of low social capital individuals, in agreement with standard economic reasoning, adds to the knowledge of the circumstances that makes the crowding out/in of intrinsic motivation likely to occur. This may help in improving the prediction and accuracy of economic models and reconcile this puzzling effect of external incentives with economic theory.