Microsatellite primer development in elasmobranchs using next generation sequencing of enriched libraries

Molecular Biology Reports - Microsatellites are useful in studies of population genetics, sibship, and parentage. Here, we screened for microsatellites from multiple elasmobranch genomic libraries...     

In Vitro Evaluation of the Effect of Stimulation with Magnetic Fields on Chondrocytes

Magnetic fields (MFs) have been used as an external stimulus to increase cell proliferation in chondrocytes and extracellular matrix (ECM) synthesis of articular cartilage. However, previously published studies have not shown that MFs are homogeneous through cell culture systems. In addition, variables such as stimulation times and MF intensities have not been standardized to obtain the best cellular proliferative rate or an increase in molecular synthesis of ECM. In this work, a stimulation device, which produces homogeneous MFs to stimulate cell culture surfaces was designed and manufactured using a computational model. Furthermore, an in vitro culture of primary rat chondrocytes was established and stimulated with two MF schemes to measure both proliferation and ECM synthesis. The best proliferation rate was obtained with an MF of 2 mT applied for 3 h, every 6 h for 8 days. In addition, the increase in the synthesis of glycosaminoglycans was statistically significant when cells were stimulated with an MF of 2 mT applied for 5 h, every 6 h for 8 days. These findings suggest that a stimulation with MFs is a promising tool that could be used to improve in vitro treatments such as autologous chondrocyte implantation, either to increase cell proliferation or stimulate molecular synthesis. Bioelectromagnetics. 2020;41:41–51 © 2019 Bioelectromagnetics Society     

Reef fishes foraging facilitation behavior: increasing the access to a food resource

Fishes associated in schools acquire adaptive advantages by grouping together, e.g., access to a larger variety of food resources, foraging sites, and protection against potential predators. This work presents the first record of a feeding association between the bucktooth parrotfish, Sparisoma radians and the sailor’s grunt Haemulon parra, on Tamandaré reefs, Southwestern Atlantic. Through this association, S. radians gained access to otherwise unavailable food resources to be found inside territorial damselfish domain, thus characterizing an event of foraging facilitation.     

Taxonomic status of southern South American Conepatus (Carnivora: Mephitidae)

Despite recent taxonomic evaluations of Mephitidae and North American hog‐nosed skunks, southern South American species of Conepatus have not been thoroughly examined in a systematic context. Conepatus chinga and Conepatus humboldtii were described more than 150 years ago, based on external characters such as hair coloration and size. Although historically recognized as valid species, to date no detailed systematic analysis has been performed for either of these taxa. Herein, we evaluated the taxonomic status of C. chinga and C. humboldtii within the southern part of South America using geometric morphometrics of the skull and mandible, mitochondrial DNA analysis using the cytochrome b and cytochrome oxidase c subunit I genes, and also control region and pelage pattern variation. We failed to find morphological (skull shape and pelage coloration patterns) or molecular differences between these two species; thus, we considered that the specimens assigned to C. chinga and C. humboldtii belong to the same species. Our results indicate that environmental variation seems to be responsible for shape and size variation in Conepatus skulls from southern South America. © 2013 The Linnean Society of London     

Taxonomy of the ‘Synargis axenus complex’ belonging to the ‘Synargis regulus’ species group,with a phylogenetic reassessment of the genus Synargis Hübner, 1819 (Lepidoptera: Riodinidae: Nymphidiini)

Three new species of Synargis Hübner, 1819, from Paraguay and southern and central Brazil are described: Synargis fandanga sp. nov. from Paraguay (Amambay and Paraguari) and southern Brazil (Paraná and Santa Catarina), Synargis rasqueada sp. nov. from central Brazil (Mato Grosso), and Synargis gorpa sp. nov. from southern Brazil (Paraná, Santa Catarina, and Rio Grande do Sul). Lectotypes are designated for Lemonias axenus Hewitson, 1876, Ematurgina axenus ochrophlegma Sitchel, 1911, Ematurgina acervata Seitz, 1932, and Ematurgina perrupta Seitz, 1932. Ematurgina ochrophlegma f. dissimilis Hayward, 1949, is a new synonym of Synargis bifasciata (Mengel, 1902), and Ematurgina ochrophlegma f. distincta Hayward, 1949, is a new synonym of Synargis axenus (Hewitson, 1876). The revalidation of E. perrupta Seitz, 1932, and the new status Synargis ochrophlegma (Stichel, 1911) are proposed. Ematurgina perrupta ab. roeberi Seitz, 1932, and Ematurgina bifasciata ochrophlegma ab. leucomelaina Breyer, 1930, are considered unavailable names. Based on a previous phylogenetic hypothesis, the phylogeny of the genus Synargis is reassessed, adding these new and revalidated taxa, and nine additional characters. The ‘Synargis regulus’ species group and the ‘Synargis axenus complex’ are recovered as monophyletic, with S. gorpa sp. nov. sister to the remaining species of the ‘S. axenus complex’. Additionally, an up‐to‐date geographical distribution map and a dichotomous key are provided, and the taxonomy of the taxa involved is discussed. © 2013 The Linnean Society of London     

Bax Inhibitor-1-mediated Ca leak is decreased by cytosolic acidosis

Bax Inhibitor-1 (BI-1) is an evolutionarily conserved six-transmembrane domain endoplasmic reticulum (ER)-localized protein that protects against ER stress-induced apoptotic cell death. This function is closely connected to its ability to lower steady-state ER Ca²⁺ levels. Recently, we elucidated BI-1's Ca²⁺-channel pore in the C-terminal part of the protein and identified the critical amino acids of its pore. Based on these insights, a Ca²⁺-channel pore-dead mutant BI-1 (BI-1^D213R) was developed. We determined whether BI-1 behaves as a bona fide H⁺/Ca²⁺ antiporter or as an ER Ca²⁺-leak channel by investigating the effect of pH on unidirectional Ca²⁺-efflux rates. At pH 6.8, wild-type BI-1 expression in BI-1^−/− cells increased the ER Ca²⁺-leak rate, correlating with its localization in the ER compartment. In contrast, BI-1^D231R expression in BI-1^−/−, despite its ER localization, did not increase the ER Ca²⁺-leak rate. However, at pH < 6.8, the BI-1-mediated ER Ca²⁺ leak was blocked. Finally, a peptide representing the Ca²⁺-channel pore of BI-1 promoting Ca²⁺ flux from the ER was used. Lowering the pH from 6.8 to 6.0 completely abolished the ability of the BI-1 peptide to mediate Ca²⁺ flux from the ER. We propose that this pH dependence is due to two aspartic acid residues critical for the function of the Ca²⁺-channel pore and located in the ER membrane-dipping domain, which facilitates the protonation of these residues.     

Anti‐tumor effect of SLPI on mammary but not colon tumor growth

Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor that was related to cancer development and metastasis dissemination on several types of tumors. However, it is not known the effect of SLPI on mammary and colon tumors. The aim of this study was to examine the effect of SLPI on mammary and colon tumor growth. The effect of SLPI was tested on in vitro cell apoptosis and in vivo tumor growth experiments. SLPI over‐expressing human and murine mammary and colon tumor cells were generated by gene transfection. The administration of murine mammary tumor cells over‐expressing high levels of SLPI did not develop tumors in mice. On the contrary, the administration of murine colon tumor cells over‐expressing SLPI, developed faster tumors than control cells. Intratumoral, but not intraperitoneal administration of SLPI, delayed the growth of tumors and increased the survival of mammary but not colon tumor bearing mice. In vitro culture of mammary tumor cell lines treated with SLPI, and SLPI producer clones were more prone to apoptosis than control cells, mainly under serum deprivation culture conditions. Herein we demonstrated that SLPI induces the apoptosis of mammary tumor cells in vitro and decreases the mammary but not colon tumor growth in vivo. Therefore, SLPI may be a new potential therapeutic tool for certain tumors, such as mammary tumors. J. Cell. Physiol. 228: 469–475, 2013. © 2012 Wiley Periodicals, Inc.     

Identification and Characterization of a High-Affinity Choline Uptake System of Brucella abortus

Phosphatidylcholine (PC), a common phospholipid of the eukaryotic cell membrane, is present in the cell envelope of the intracellular pathogen Brucella abortus, the etiological agent of bovine brucellosis. In this pathogen, the biosynthesis of PC proceeds mainly through the phosphatidylcholine synthase pathway; hence, it relies on the presence of choline in the milieu. These observations imply that B. abortus encodes an as-yet-unknown choline uptake system. Taking advantage of the requirement of choline uptake for PC synthesis, we devised a method that allowed us to identify a homologue of ChoX, the high-affinity periplasmic binding protein of the ABC transporter ChoXWV. Disruption of the choX gene completely abrogated PC synthesis at low choline concentrations in the medium, thus indicating that it is a high-affinity transporter needed for PC synthesis via the PC synthase (PCS) pathway. However, the synthesis of PC was restored when the mutant was incubated in media with higher choline concentrations, suggesting the presence of an alternative low-affinity choline uptake activity. By means of a fluorescence-based equilibrium-binding assay and using the kinetics of radiolabeled choline uptake, we show that ChoX binds choline with an extremely high affinity, and we also demonstrate that its activity is inhibited by increasing choline concentrations. Cell infection assays indicate that ChoX activity is required during the first phase of B. abortus intracellular traffic, suggesting that choline concentrations in the early and intermediate Brucella-containing vacuoles are limited. Altogether, these results suggest that choline transport and PC synthesis are strictly regulated in B. abortus.     

Modulation of Lipid Kinase PI4KIIα Activity and Lipid Raft Association of Presenilin 1 Underlies γ-Secretase Inhibition by Ginsenoside (20S)-Rg3

Amyloid β-peptide (Aβ) pathology is an invariant feature of Alzheimer disease, preceding any detectable clinical symptoms by more than a decade. To this end, we seek to identify agents that can reduce Aβ levels in the brain via novel mechanisms. We found that (20S)-Rg3, a triterpene natural compound known as ginsenoside, reduced Aβ levels in cultured primary neurons and in the brains of a mouse model of Alzheimer disease. The (20S)-Rg3 treatment induced a decrease in the association of presenilin 1 (PS1) fragments with lipid rafts where catalytic components of the γ-secretase complex are enriched. The Aβ-lowering activity of (20S)-Rg3 directly correlated with increased activity of phosphatidylinositol 4-kinase IIα (PI4KIIα), a lipid kinase that mediates the rate-limiting step in phosphatidylinositol 4,5-bisphosphate synthesis. PI4KIIα overexpression recapitulated the effects of (20S)-Rg3, whereas reduced expression of PI4KIIα abolished the Aβ-reducing activity of (20S)-Rg3 in neurons. Our results substantiate an important role for PI4KIIα and phosphoinositide modulation in γ-secretase activity and Aβ biogenesis.