Asexual Reproduction and Segmental Regeneration, but not Morphallaxis, are Inhibited by Boric Acid in Lumbriculus variegatus (Annelida: Clitellata: Lumbriculidae)

Body fragmentation, in some animal groups, is a mechanism for survival and asexual reproduction. Lumbriculus variegatus (Müller, 1774), an aquatic oligochaete worm, is capable of regenerating into complete individuals from small body fragments following injury and reproduces primarily by asexual reproduction. Few studies have determined the cellular mechanisms that underlie fragmentation, either regenerative or asexual. We utilized boric acid treatment, which blocks regeneration of segments in amputated fragments and blocks architomic fission during asexual reproduction, to investigate mechanistic relationships and differences between these two modes of development. Neural morphallaxis, involving changes in sensory fields and giant fiber conduction, was detected in amputated fragments in the absence of segmental regeneration. Furthermore, neural morphallactic changes occurred as a result of developmental mechanisms of asexual reproduction, even when architomy was prevented. These results show that fragmentation in L. variegatus, during injury or asexual reproduction, employs developmental and morphallactic processes that can be mechanistically dissociated by boric acid exposure. In regeneration following injury, compensatory morphallaxis occurred in response to fragmentation. In contrast, anticipatory morphallaxis was induced in preparation for fragmentation during asexual reproduction. Thus, various forms of regeneration in this lumbriculid worm can be activated independently and in different developmental contexts.     

Mapping of the Interaction Site between Sortilin and the p75 Neurotrophin Receptor Reveals a Regulatory Role for the Sortilin Intracellular Domain in p75 Neurotrophin Receptor Shedding and Apoptosis

Neurotrophins comprise a group of neuronal growth factors that are essential for the development and maintenance of the nervous system. However, the immature pro-neurotrophins promote apoptosis by engaging in a complex with sortilin and the p75 neurotrophin receptor (p75^NTR). To identify the interaction site between sortilin and p75^NTR, we analyzed binding between chimeric receptor constructs and truncated p75^NTR variants by co-immunoprecipitation experiments, surface plasmon resonance analysis, and FRET. We found that complex formation between sortilin and p75^NTR relies on contact points in the extracellular domains of the receptors. We also determined that the interaction critically depends on an extracellular juxtamembrane 23-amino acid sequence of p75^NTR. Functional studies further revealed an important regulatory function of the sortilin intracellular domain in p75^NTR-regulated intramembrane proteolysis and apoptosis. Thus, although the intracellular domain of sortilin does not contribute to p75^NTR binding, it does regulate the rates of p75^NTR cleavage, which is required to mediate pro-neurotrophin-stimulated cell death.     

let-7 microRNAs induce tamoxifen sensitivity by downregulation of estrogen receptor α signaling in breast cancer

MicroRNAs (miRNAs) play an important regulatory role in breast tumorigenesis. Previously, we found that let-7 miRNAs were downregulated significantly in formalin-fixed paraffin-embedded (FFPE) breast cancer tissues. In this study, we further found that endogenous levels of let-7b and let-7i miRNAs are inversely correlated with levels of estrogen receptor (ER)-a36, a new variant of ER-α66, in the FFPE tissue set. Bioinformatic analysis suggested that ER-α36 may be another target of let-7 miRNAs. To test this hypothesis, cotransfection of let-7 mimics or inhibitors together with full-length or a fragment of ER-α36 3'UTR luciferase construct was performed, and we found that let-7b and let-7i mimics suppressed the activity of reporter gene significantly, which was enhanced remarkably by let-7b and let-7i inhibitors. Both mRNA and protein expression of ER-α36 were inhibited by let-7 mimics and enhanced by let-7 inhibitors. Furthermore, ER-α36 mediated nongenomic MAPK and Akt pathways were weakened by let-7b and let-7i mimics in triple negative breast cancer cell line MDA-MB-231. The reverse correlation between let-7 miRNAs and ER-α36 also exists in Tamoxifen (Tam)-resistant MCF7 cell line. Transfection of let-7 mimics to Tam-resistant MCF7 cells downregulated ER-α36 expression and enhanced the sensitivity of MCF7 cells to Tam in estrogen-free medium, which could be restored by overexpression of ER-α36 constructs without 3'UTR. Our results suggested a novel regulatory mechanism of let-7 miRNAs on ER-α36 mediated nongenomic estrogen signal pathways and Tam resistance.     

Hunt or hide: How insularity and urbanization affect foraging decisions in lizards

Foraging decisions should reflect a balance between costs and benefits of alternative strategies. Predation risk and resource availability in the environment may be crucial in deciding how cautious individuals should behave during foraging. These costs and benefits will vary in time and context, meaning that animals should be able to adjust their foraging behaviour to new or altered environments. Studying how animals do this is essential to understand their survival in these environments. In this study, we investigated the effect of both insularity and urbanization on risk‐taking and neophobia during foraging in the Dalmatian wall lizard (Podarcis melisellensis). Small islets tend to have both a lower number of predators and less resources. Therefore, islet populations were expected to show more risk‐taking behaviour and less neophobia in a foraging context. Previous studies on behaviour of urban lizards have yielded inconsistent results, but due to a lack of both predators and arthropod prey in urban habitats, we expected urban lizards to also take more risks and behave less neophobic. We sampled several inhabited and uninhabited locations on Vis (Croatia) and surrounding islets. Risk‐taking behaviour was tested by measuring the latency of lizards to feed in the presence of a predator model, and neophobia by measuring the latency to feed in the presence of a novel object. We found that islet lizards do indeed take more risks and were less vigilant, but not less neophobic. Urban and rural lizards did not differ in any of these behaviours, which is in sharp contrast with previous work on mammals and birds. The behavioural differences between islet and island lizards were novel, but not unexpected findings and are in line with the theory of “island tameness”. The effect of urbanization on the behaviour of animals seems to be more complex and might vary among taxa.     

Endoscopically assisted latissimus dorsi flap harvesting and breast reconstruction in young female with Poland syndrome

We will describe a second phase of breast reconstruction on a young girl suffering from Poland syndrome. She has the breast, pectoralis major and minor muscle aplasia on the right side. She has no other deformities. The best result is achieved by combining latissimus dorsi flap and a silicone implant, and even better aesthetic result is accomplished with endoscopically assisted latissimus dorsi harvesting. Purpose of this operation is to correct the chest asymmetry and to accomplish good aesthetic result.     

Organisms of deep sea hydrothermal vents as a source for studying adaptation and evolution

It has been postulated that life originated in a similar environment to those of deep sea hydrothermal vents. These environments are located along volcanic ridges and are characterized by extreme conditions such as unique physical properties (temperature, pressure), chemical toxicity, and absence of photosynthesis. However, numerous living organisms have been discovered in these hostile environments, including a variety of microorganisms and many animal species which live in intimate and complex symbioses with sulfo-oxidizing and methanotrophic bacteria. Recent proteomic analyses of the endosymbiont ofRiftia pachyptila and genome sequences of some free living and symbiotic bacteria have provided complementary information about the potential metabolic and genomic capacities of these organisms. The evolution of these adaptive strategies is connected with different mechanisms of genetic adaptation including horizontal gene transfer and . various structural and functional mutations. Therefore, the organisms in this environment are good models for studying the evolution of prokaryotes and eukaryotes as well as different aspects of the biology of adaptation. This review describes some current research concerning metabolic and plausible genetic adaptations of organisms in a deep sea environment, usingRiftia pachyptila as model.     

Coexistence of Probe Conformations in Lipid Phases—A Polarized Fluorescence Microspectroscopy Study

Several well-established fluorescence methods depend on environment-sensitive probes that report about molecular properties of their local environment. For reliable interpretation of experiments, careful characterization of probes’ behavior is required. In this study, bleaching-corrected polarized fluorescence microspectroscopy with nanometer spectral peak position resolution was applied to characterize conformations of two alkyl chain-labeled 7-nitro-2-1,3-benzoxadiazol-4-yl phospholipids in three model membranes, representing the three main lipid phases. The combination of polarized and spectral detection revealed two main probe conformations with their preferential fluorophore dipole orientations roughly parallel and perpendicular to membrane normal. Their peak positions were separated by 2–6 nm because of different local polarities and depended on lipid environment. The relative populations of conformations, estimated by a numerical model, indicated a specific sensitivity of the two probes to molecular packing with cholesterol. The coexistence of probe conformations could be further exploited to investigate membrane organization below microscopy spatial resolution, such as lipid rafts. With the addition of polarized excitation or detection to any environment-sensitive fluorescence imaging technique, the conformational analysis can be directly applied to explore local membrane complexity.     

Identification of a novel glycosyltransferase involved in LOS biosynthesis of Moraxella catarrhalis

Moraxella catarrhalis is an important human mucosal pathogen that contributes to otitis media in infants and exacerbates conditions such as chronic obstructive pulmonary disease in the elderly. This study describes the identification of a novel gene, lgt5 that encodes a glycosyltransferase involved in the LOS biosynthesis of M. catarrhalis. Analysis of NMR data of LOS-derived oligosaccharide from a Serotype A lgt5 mutant strain of M. catarrhalis indicate that lgt5 encodes an alpha-(1-->4)-galactosyltransferase.     

Quantifying the Consistency of Scientific Databases

Science is a social process with far-reaching impact on our modern society. In recent years, for the first time we are able to scientifically study the science itself. This is enabled by massive amounts of data on scientific publications that is increasingly becoming available. The data is contained in several databases such as Web of Science or PubMed, maintained by various public and private entities. Unfortunately, these databases are not always consistent, which considerably hinders this study. Relying on the powerful framework of complex networks, we conduct a systematic analysis of the consistency among six major scientific databases. We found that identifying a single "best" database is far from easy. Nevertheless, our results indicate appreciable differences in mutual consistency of different databases, which we interpret as recipes for future bibliometric studies.     

Comparison of two approaches for quantitative O-linked glycan analysis used in characterization of recombinant proteins

The principal aim of this study was to demonstrate the optimization and fine-tuning of quantitative and nonselective analysis of O-linked glycans released from therapeutic glycoproteins. Two approaches for quantitative release of O-linked glycans were examined: ammonia-based β-elimination and hydrazinolysis deglycosylation strategies. A significant discrepancy in deglycosylation activity was observed between the ammonia-based and hydrazinolysis procedures. Specifically, the release of O-glycans from glycoproteins was approximately 20 to 30 times more efficient with hydrazine compared with ammonia-based β-elimination reagent. In addition, the ammonia-based reagent demonstrated bias in the release of particular glycan species. A robust quantitative hydrazinolysis procedure was developed for characterization of O-glycans. The method performance parameters were evaluated. It was shown that this procedure is superior for quantitative nonselective release of O-glycans. Identity confirmation and structure elucidation of O-glycans from hydrophilic interaction chromatography (HILIC) fractions was also demonstrated using linear ion trap Fourier transform mass spectrometry (LTQ FT MS) with mass accuracy below 1 ppm.