Correlated divergence of female and male genitalia in replicated lineages with ongoing ecological speciation

Divergence of genital traits among lineages has the potential to serve as a reproductive isolating barrier when copulation, insemination, and fertilization are inhibited by incompatibilities between female and male genitalia. Despite widespread evidence for genital trait diversity among closely related lineages and coevolution of female and male genitalia within lineages, few studies have investigated genital evolution during the early stages of speciation. We quantified genital variation in replicated population pairs of Poecilia mexicana with ongoing ecological speciation between sulfidic (H₂S containing) and nearby nonsulfidic habitats. These analyses revealed rapid and correlated divergence of female and male genitalia across evolutionarily independent population pairs exposed to divergent selection regimes. Both sexes exhibited convergent evolution of genital traits among populations inhabiting similar habitat types. Our results demonstrate that genital evolution can occur during the early stages of speciation‐with‐gene‐flow, potentially as a result of variation in the intensity of sexual conflict among populations. Our results suggest genitalia may contribute to early stages of divergence and challenge the generality of previously suggested mechanisms of genital evolution in poeciliids.     

Palmitic Acid-Induced NAD+ Depletion is Associated with the Reduced Function of SIRT1 and Increased Expression of BACE1 in Hippocampal Neurons

Increased levels of circulating fatty acids, such as palmitic acid (PA), are associated with the development of obesity, insulin resistance, type-2 diabetes and metabolic syndrome. Furthermore, these diseases are linked to an increased risk of cancer, cardiovascular diseases, mild cognitive impairment and even Alzheimer’s disease (AD). However, the precise actions of elevated PA levels on neurons and their association with neuronal metabolic disruption that leads to the expression of pathological markers of AD, such as the overproduction and accumulation of the amyloid-β peptide, represent an area of intense investigation. A possible molecular mechanism involved in the effects of PA may be through dysfunction of the NAD⁺ sensor enzyme, SIRT1. Therefore, the aim of the present study was to analyze the relationship between the effects of PA metabolism on the function of SIRT1 and the upregulation of BACE1 in cultured hippocampal neurons. PA reduced the total amount of NAD⁺ in neurons that caused an increase in p65 K310 acetylation due to inhibition of SIRT1 activity and low protein content. Furthermore, BACE1 protein and its activity were increased, and BACE1 was relocated in neurites after PA exposure.

     

Effect of the presence and location of corpus luteum on competence of bovine cumulus-oocyte complexes

This study aimed to determine the effect of presence of the corpus luteum (CL) and its influence on cumulus–oocyte complexes (COCs) obtained from the ipsilateral or contralateral ovary in bovine on the recovery and capacity of the oocytes to sustain mono-spermic fertilization, undergo preimplantation development, and develop to the blastocyst stage. Ovaries were collected at a local slaughterhouse and kept in pairs corresponding to the same animal. In the first experiment the variables evaluated were compared between cows with (CCL⁺) and without (CCL^-) CL, and for the second experiment, comparisons were made between ovaries with an ipsilateral (CL⁺), contralateral (CL⁻), and no (NCL). The recovery rate of COCs was higher in ovaries from CCL⁻ cows, and a higher proportion of grade 1 COCs were recovered from this group. A higher proportion of metaphase I oocytes at 7 h of maturation, and a higher rate of cleavage were observed in the CCL⁺ group; however, a higher proportion of embryos were obtained from the CCL⁻ group. Besides, COCs from the CL⁺ group had a lower proportion of grades 1 and 2 morphological qualities, lower rate of metaphase II oocytes at 22 h of maturation, and lower rate of formation of two pronuclei, whereas a higher proportion of unfertilized oocytes after in vitro fertilization. On the other hand, the COCs from the CL⁻ group displayed a lower proportion of oocytes with more than two pronuclei, higher cleavage rate, and higher final blastocyst production were obtained when compared to CL+. Thus, the effects of CL on the competence of bovine COCs are different depending on the anatomical proximity of their location in the animal, negatively affecting the quality of COCs located in the same ovary, but not having negative effects on the competence of COCs in the ovaries contralateral to their location.     

First record for the European Ichthyofauna of Dentex (Cheimerius) canariensis Steindachner, 1881

Dentex ( Cheimerius ) canariensis is recorded for the first time for European waters, on the basis of four specimens captured on the coast of Cádiz (SW Iberian peninsula).     

Glycerol 3-phosphate inhibits swarming and aggregation of Myxococcus xanthus

We have cloned a gene of Myxococcus xanthus with similarities to the permease for glycerol 3-phosphate (G3P) of other bacteria. Expression of the gene increased significantly during the first hours of starvation. Swarming of the wild-type strain was inhibited and aggregation was delayed by G3P. Conversely, a DeltaglpT strain aggregated even on rich medium. These results indicate that G3P may function to regulate the timing of aggregation in M. xanthus.     

Low incidence of Vibrio vulnificus among Vibrio isolates from sea water and shellfish of the western Mediterranean coast

A specific search for Vibrio vulnificus in natural marine samples from the Spanish Mediterranean Sea was carried out by nested PCR and cultural approaches using thiosulphate-citrate-bile salts-sucrose agar (TCBS) and cellobiose-polymixin B-colistin agar (CPC), incubated at 40 degrees C, as selective media. Presumptive colonies were identified by PCR using specific primers against 23S rRNA sequences. This species was isolated from sea water and edible bivalves, mainly after preenrichment in alkaline peptone water (APW) at 40 degrees C followed by CPC agar. None of the V. vulnificus isolates identified corresponded to serovar E. Dominant Vibrio species on directly inoculated TCBS plates incubated at 25 degrees C were V. splendidus below 20 degrees C and V. harveyi and V. mediterranei above that temperature. Low percentages of several pathogenic vibrios were recorded but V. vulnificus was never recovered at this incubation temperature. The incidence of this species in the samples studied was lower than that described for other geographical areas, probably due to the high salinity values of the Mediterranean Sea.     

Wingless modulates the effects of dominant negative notch molecules in the developing wing of Drosophila

The development and patterning of the wing in Drosophila relies on a sequence of cell interactions molecularly driven by a number of ligands and receptors. Genetic analysis indicates that a receptor encoded by the Notch gene and a signal encoded by the wingless gene play a number of interdependent roles in this process and display very strong functional interactions. At certain times and places, during wing development, the expression of wingless requires Notch activity and that of its ligands Delta and Serrate. This has led to the proposal that all the interactions between Notch and wingless can be understood in terms of this regulatory relationship. Here we have tested this proposal by analysing interactions between Delta- and Serrate-activated Notch signalling and Wingless signalling during wing development and patterning. We find that the cell death caused by expressing dominant negative Notch molecules during wing development cannot be rescued by coexpressing Nintra. This suggests that the dominant negative Notch molecules cannot only disrupt Delta and Serrate signalling but can also disrupt signalling through another pathway. One possibility is the Wingless signalling pathway as the cell death caused by expressing dominant negative Notch molecules can be rescued by activating Wingless signalling. Furthermore, we observe that the outcome of the interactions between Notch and Wingless signalling differs when we activate Wingless signalling by expressing either Wingless itself or an activated form of the Armadillo. For example, the effect of expressing the activated form of Armadillo with a dominant negative Notch on the patterning of sense organ precursors in the wing resembles the effects of expressing Wingless alone. This result suggests that signalling activated by Wingless leads to two effects, a reduction of Notch signalling and an activation of Armadillo.     

Mapping of bovine ovulation rate QTL; an analytical approach for three generation pedigrees

Interval mapping was conducted for ovulation rate quantitative trait loci (QTL) using data from two related families from the United States Department of Agriculture, US Meat Animal Research Center twinning cattle herd. Both families are extended, three generation pedigrees from which records of sons, daughters and granddaughters were analysed. Both a method of analysis and results from that analysis are reported herein. Results from one of the two families (839802) were previously reported, but reanalysis here including the second, related family (839803) and a revised statistical model lessens support for the previously reported QTL. Results from interval mapping provided evidence for QTL in regions corresponding to those previously suggested for chromosomes 7 (chromosome-wise P < 0.05) and 19 (chromosome-wise P < 0.01) in the 839802 family, although statistical significance was reduced. In contrast to the previous report, evidence for a chromosome 5 QTL in the same family was greatly reduced while support for a QTL on chromosome 10 increased (chromosome-wise P < 0.01). Analysis of data from the related 839803 family failed to replicate evidence of QTL observed on either chromosome 7 or chromosome 19 in the 839802 family.