Efflux of Osmolyte Amino Acids during Isovolumic Regulation in Hippocampal Slices

The efflux of potassium (K+) and amino acids from hippocampal slices was measured after sudden exposure to 10% (270 mOsm), 25% (225 mOsm) or 50% (150 mOsm) hyposmotic solutions or after gradual decrease (22.5 mOsm/min) in external osmolarity. In slices suddenly exposed to 50% hyposmotic solutions, swelling was followed by partial (74%) cell volume recovery, suggesting regulatory volume decrease (RVD). With gradual hyposmotic changes, no increase in cell water content was observed even when the solution at the end of the experiment was 50% hyposmotic, showing the occurrence of isovolumic regulation (IVR). The gradual decrease in osmolarity elicited the efflux of 3H-taurine with a threshold at –5 mOsm and D-[3H]aspartate (as marker for glutamate) and at –20 mOsm for [3H]GABA. The efflux rate of [3H]taurine was always notably higher than those of [3H]GABA and D-[3H]aspartate, with a maximal increase over the isosmotic efflux of about 7-fold for [3H]taurine and 3- and 2-fold for [3H]GABA and D-[3H]aspartate, respectively. The amino acid content in slices exposed to 50% hyposmotic solutions (abrupt change) during 20 min decreased by 50.6% and 62.6% (gradual change). Taurine and glutamate showed the largest decrease. An enhancement in 86Rb efflux and a corresponding decrease in K+ tissue content was seen in association with RVD but not with IVR. These results demonstrate the contribution of amino acids to IVR and indicate their involvement in this mechanism of cell volume control

Efflux of Osmolyte Amino Acids during Isovolumic Regulation in Hippocampal Slices

The efflux of potassium (K+) and amino acids from hippocampal slices was measured after sudden exposure to 10% (270 mOsm), 25% (225 mOsm) or 50% (150 mOsm) hyposmotic solutions or after gradual decrease (22.5 mOsm/min) in external osmolarity. In slices suddenly exposed to 50% hyposmotic solutions, swelling was followed by partial (74%) cell volume recovery, suggesting regulatory volume decrease (RVD). With gradual hyposmotic changes, no increase in cell water content was observed even when the solution at the end of the experiment was 50% hyposmotic, showing the occurrence of isovolumic regulation (IVR). The gradual decrease in osmolarity elicited the efflux of 3H-taurine with a threshold at –5 mOsm and D-[3H]aspartate (as marker for glutamate) and at –20 mOsm for [3H]GABA. The efflux rate of [3H]taurine was always notably higher than those of [3H]GABA and D-[3H]aspartate, with a maximal increase over the isosmotic efflux of about 7-fold for [3H]taurine and 3- and 2-fold for [3H]GABA and D-[3H]aspartate, respectively. The amino acid content in slices exposed to 50% hyposmotic solutions (abrupt change) during 20 min decreased by 50.6% and 62.6% (gradual change). Taurine and glutamate showed the largest decrease. An enhancement in 86Rb efflux and a corresponding decrease in K+ tissue content was seen in association with RVD but not with IVR. These results demonstrate the contribution of amino acids to IVR and indicate their involvement in this mechanism of cell volume control

Analysis and Characterization of Diallyldimethylammonium Chloride and Its Polymers in a Control Laboratory

[Resumen] La realización de las prácticas externas en Arteixo Química S.L. tuvo una duración de 15 semanas (400 horas). El trabajo hecho durante este período se realizó en el laboratorio de control de calidad y consistió en el análisis de los productos fabricados para el control del proceso de síntesis y en el análisis de los productos finales. En esta fábrica se producen tensioactivos, polímeros y otros productos de química fina. Además, su actividad de producción es de 24 horas al día. Por ello, el número de muestras a analizar es muy elevado, lo que permitió que pudiese conocer una gran variedad de productos. Sin embargo, este trabajo se centra en el análisis del cloruro de dialildimetilamonio, que es el monómero a partir del cual se sintetizan diferentes polímeros. Se ha escogido el estudio de este monómero y sus polímeros ya que son los productos más demandados de los que se producen en esta fábrica por su gran eficacia en el tratamiento de aguas. En este trabajo se describen los análisis realizados para determinar los parámetros necesarios para controlar el proceso de producción y los parámetros necesarios para la caracterización tanto del monómero como de los polímeros. Los parámetros analizados en el monómero son: (1) el contenido de impurezas; mediante cromatografía de gases, (2) el porcentaje de residuos sólidos, (3) el pH, (4) el índice de neutralización, (5) el contenido de cloruro total, (6) el contenido de cloruro sódico y (7) el color. Mientras que en los polímeros se determinan: (1) el contenido residual de monómero libre; mediante HPLC, (2) el porcentaje de residuos sólidos, (3) el pH, (4) la viscosidad y (6) el color.[Abstract] Carrying out external internships at Arteixo Química S.L. it lasted 15 weeks (400 hours). The work done during this period was carried out in the quality control laboratory and consisted of the analysis of the manufactured products for the control of the synthesis process and the analysis of the final products. Surfactants, polymers and other fine chemical products are produced in this factory. In addition, its production activity is 24 hours a day. For this reason, the number of samples to be analyzed is very high, which allowed it to discover a wide variety of products. However, this work focuses on the analysis of the diallyldimethylammonium chloride, which is the monomer from which different polymers are synthesized. The study of this monomer and its polymers has been chosen since they are the most demanded products produced in this factory due to their great efficiency in water treatment. This paper descries the analysis carried out to determine the parameters necessary to control the production process and the parameters necessary for the characterization of both the monomer and the polymers. The parameters analysed in the monomer are: (1) the content of impurities by gas chromatography, (2) the percentage of solid waste, (3) the pH, (4) the neutralization index, (5) the total chloride content, (6) sodium chloride content and (7) the colour. While in the polymers are determined: (1) the residual content of free monomer is determined by means of high resolution liquid chromatography, (2) the percentage of solid residues, (3) the pH, (4) the viscosity and (5) the colour.Traballo fin de mestrado (UDC.CIE). Investigación química y química industrial. Curso 2021/202

Chromosomal mapping of rRNA genes, core histone genes and telomeric sequences in Brachidontes puniceus and Brachidontes rodriguezi (Bivalvia, Mytilidae)

<p>Abstract</p> <p>Background</p> <p>Chromosome rearrangements are an important part of the speciation process in many taxa. The study of chromosome evolution in bivalves is hampered by the absence of clear chromosomal banding patterns and the similarity in both chromosome size and morphology. For this reason, obtaining good chromosome markers is essential for reliable karyotypic comparisons. To begin this task, the chromosomes of the mussels <it>Brachidontes puniceus </it>and <it>B. rodriguezi </it>were studied by means of fluorochrome staining and fluorescent <it>in situ </it>hybridization (FISH).</p> <p>Results</p> <p><it>Brachidontes puniceus </it>and <it>B. rodriguezi </it>both have 2n = 32 chromosomes but differing karyotype composition. Vertebrate-type telomeric sequences appear at both ends of every single chromosome. <it>B. puniceus </it>presents a single terminal major rRNA gene cluster on a chromosome pair while <it>B. rodriguezi </it>shows two. Both mussels present two 5S rDNA and two core histone gene clusters intercalary located on the long arms of two chromosome pairs. Double and triple-FISH experiments demonstrated that one of the 5S rDNA and one of the major rDNA clusters appear on the same chromosome pair in <it>B. rodriguezi </it>but not in <it>B. puniceus</it>. On the other hand, the second 5S rDNA cluster is located in one of the chromosome pairs also bearing one of the core histone gene clusters in the two mussel species.</p> <p>Conclusion</p> <p>Knowledge of the chromosomal distribution of these sequences in the two species of <it>Brachidontes </it>is a first step in the understanding of the role of chromosome changes on bivalve evolution.</p

Terminal-repeat retrotransposons in miniature (TRIMs) in bivalves

Terminal repeat retrotransposons in miniature (TRIMs) are small non-autonomous LTR retrotransposons consisting of two terminal direct repeats surrounding a short internal domain. The detection and characterization of these elements has been mainly limited to plants. Here we present the first finding of a TRIM element in bivalves, and among the first known in the kingdom Animalia. Class Bivalvia has high ecological and commercial importance in marine ecosystems and aquaculture, and, in recent years, an increasing number of genomic studies has addressed to these organisms. We have identified biv-TRIM in several bivalve species: Donax trunculus, Ruditapes decussatus, R. philippinarum, Venerupis corrugata, Polititapes rhomboides, Venus verrucosa, Dosinia exoleta, Glycymeris glycymeris, Cerastoderma edule, Magallana gigas, Mytilus galloprovincialis. biv-TRIM has several characteristics typical for this group of elements, exhibiting different variations. In addition to canonically structured elements, solo-TDRs and tandem repeats were detected. The presence of this element in the genome of each species is <1%. The phylogenetic analysis showed a complex clustering pattern of biv-TRIM elements, and indicates the involvement of horizontal transfer in the spreading of this elementXunta de Galicia | Ref. ED431C 2016-037Xunta de Galicia | Ref. ED481B/2018/091Ministarstvo Znanosti, Obrazovanja i Sporta | Ref. 098-0982913-275

Y Chromosomal Variation Tracks the Evolution of Mating Systems in Chimpanzee and Bonobo

The male-specific regions of the Y chromosome (MSY) of the human and the chimpanzee (Pan troglodytes) are fully sequenced. The most striking difference is the dramatic rearrangement of large parts of their respective MSYs. These non-recombining regions include ampliconic gene families that are known to be important for male reproduction,and are consequently under significant selective pressure. However, whether the published Y-chromosomal pattern of ampliconic fertility genes is invariable within P. troglodytes is an open but fundamental question pertinent to discussions of the evolutionary fate of the Y chromosome in different primate mating systems. To solve this question we applied fluorescence in situ hybridisation (FISH) of testis-specific expressed ampliconic fertility genes to metaphase Y chromosomes of 17 chimpanzees derived from 11 wild-born males and 16 bonobos representing seven wild-born males. We show that of eleven P. troglodytes Y-chromosomal lines, ten Y-chromosomal variants were detected based on the number and arrangement of the ampliconic fertility genes DAZ (deleted in azoospermia) and CDY (chromodomain protein Y)—a so-far never-described variation of a species' Y chromosome. In marked contrast, no variation was evident among seven Y-chromosomal lines of the bonobo, P. paniscus, the chimpanzee's closest living relative. Although, loss of variation of the Y chromosome in the bonobo by a founder effect or genetic drift cannot be excluded, these contrasting patterns might be explained in the context of the species' markedly different social and mating behaviour. In chimpanzees, multiple males copulate with a receptive female during a short period of visible anogenital swelling, and this may place significant selection on fertility genes. In bonobos, however, female mate choice may make sperm competition redundant (leading to monomorphism of fertility genes), since ovulation in this species is concealed by the prolonged anogenital swelling, and because female bonobos can occupy high-ranking positions in the group and are thus able to determine mate choice more freely

Chromosomal evolution of the PKD1 gene family in primates

Correction to Kirsch S, Pasantes J, Wolf A, Bogdanova N, Münch C, Pennekamp P, Krawczak M, Dworniczak B, Schempp W: Chromosomal evolution of the PKD1 gene family in primates. BMC Evolutionary Biology 2008, 8:263 (doi:10.1186/1471-2148-8-263

Differential modulation of human GABAC‑ρ1 receptor by sulfur‑containing compounds structurally related to taurine

Background: The amino acid taurine (2-Aminoethanesulfonic acid) modulates inhibitory neurotransmitter receptors. This study aimed to determine if the dual action of taurine on GABAC- ρ1R relates to its structure. To address this, we tested the ability of the structurally related compounds homotaurine, hypotaurine, and isethionic acid to modulate GABAC- ρ1R. Results: In Xenopus laevis oocytes, hypotaurine and homotaurine partially activate heterologously expressed GABAC- ρ1R, showing an increment in its deactivation time with no changes in channel permeability, whereas isethionic acid showed no effect. Competitive assays suggest that hypotaurine and homotaurine compete for the GABA-binding site. In addition, their effects were blocked by the ion-channel blockers picrotixin and Methyl(1,2,5,6- tetrahydropyridine-4-yl) phosphinic acid. In contrast to taurine, co-application of GABA with hypotaurine or homotaurine revealed that the dual effect is present separately for each compound: hypotaurine modulates positively the GABA current, while homotaurine shows a negative modulation, both in a dose-dependent manner. Interestingly, homotaurine diminished hypotaurine-induced currents. Thus, these results strongly suggest a competitive interaction between GABA and homotaurine or hypotaurine for the same binding site. “In silico” modeling confirms these observations, but it also shows a second binding site for homotaurine, which could explain the negative effect of this compound on the current generated by GABA or hypotaurine, during co-application protocols. Conclusions: The sulfur-containing compounds structurally related to taurine are partial agonists of GABAC- ρ1R that occupy the agonist binding site. The dual effect is unique to taurine, whereas in the case of hypotaurine and homotaurine it presents separately; hypotaurine increases and homotaurine decreases the GABA current

Seasonal variation in the incidence of preeclampsia and eclampsia in tropical climatic conditions

<p>Abstract</p> <p>Background</p> <p>Observational studies have demonstrated various correlations between hypertensive disorders of pregnancy and different weather parameters. We aim to study if a correlation exists between the incidence of eclampsia and pre-eclampsia and various weather parameters in the tropical coastal city of Mumbai which has the distinction of having relatively uniform meteorological variables all throughout the year, except for the monsoon season.</p> <p>Methods</p> <p>We retrospectively analysed data from a large maternity centre in Mumbai, India over a period of 36 months from March 1993 to February 1996, recording the incidence of preeclampsia and eclampsia. Meteorological data was acquired from the regional meteorological centre recording the monthly average temperature, humidity, barometric pressure and rainfall during the study period. Study period was then divided into two climate conditions: monsoon season (June to August) and dry season September to May. The incidence of preeclampsia and eclampsia and the meteorological differences between the two seasons were compared.</p> <p>Results</p> <p>Over a 36-month period, a total of 29562 deliveries were recorded, of which 1238 patients developed preeclampsia (4.18%) and 34 developed eclampsia (0.11%). The incidence of preeclampsia did not differ between the monsoon and the dry season (4.3% vs. 4.15%, p = 0.5). The incidence of eclampsia was significantly higher in the monsoon (0.2% vs. 0.08%, p = 0.01). The monsoon was significantly cooler (median maximum temperature 30.7°C vs. 32.3°C, p = 0.01), more humid (median relative humidity 85% vs. 70%, p = 0.0008), and received higher rainfall (median 504.9 mm vs. 0.3 mm, p = 0.0002) than the rest of the year. The median barometric pressure (1005 mb) during the monsoon season was significantly lower than the rest of the year (1012 mb, p < 0.0001).</p> <p>Conclusion</p> <p>In the tropical climate of Mumbai, the incidence of eclampsia is significantly higher in monsoon, when the weather is cooler and humid with a lower barometric pressure than the rest of the year. This effect is not seen with preeclampsia. This strengthens the association of low temperature and high humidity with triggering of eclampsia.</p

Satellitome Analysis of the Pacific Oyster Crassostrea gigas Reveals New Pattern of Satellite DNA Organization, Highly Scattered across the Genome

Several features already qualified the invasive bivalve species Crassostrea gigas as a valuable non-standard model organism in genome research. C. gigas is characterized by the low contribution of satellite DNAs (satDNAs) vs. mobile elements and has an extremely low amount of heterochromatin, predominantly built of DNA transposons. In this work, we have identified 52 satDNAs composing the satellitome of C. gigas and constituting about 6.33% of the genome. Satellitome analysis reveals unusual, highly scattered organization of relatively short satDNA arrays across the whole genome. However, peculiar chromosomal distribution and densities are specific for each satDNA. The inspection of the organizational forms of the 11 most abundant satDNAs shows association with constitutive parts of Helitron mobile elements. Nine of the inspected satDNAs are dominantly found in mobile element-associated form, two mostly appear standalone, and only one is present exclusively as Helitron-associated sequence. The Helitron-related satDNAs appear in more chromosomes than other satDNAs, indicating that these mobile elements could be leading satDNA propagation in C. gigas. No significant accumulation of satDNAs on certain chromosomal positions was detected in C. gigas, thus establishing a novel pattern of satDNA organization on the genome level