Phenotypic plasticity or speciation? A case from a clonal marine organism

<p>Abstract</p> <p>Background</p> <p>Clonal marine organisms exhibit high levels of morphological variation. Morphological differences may be a response to environmental factors but also they can be attributed to accumulated genetic differences due to disruption of gene flow among populations. In this study, we examined the extensive morphological variation (of 14 characters) in natural populations observed in the gorgonian <it>Eunicea flexuosa</it>, a widely distributed Caribbean octocoral. Eco-phenotypic and genetic effects were evaluated by reciprocal transplants of colonies inhabiting opposite ends of the depth gradient and analysis of population genetics of mitochondrial and nuclear genes, respectively.</p> <p>Results</p> <p>Significant differences (P < 0.001) in 14 morphological traits were found among colonies inhabiting 12 locations distributed in seven reefs in southwest Puerto Rico. Results from principal component analysis indicated the presence of two groups based on depth distribution, suggesting the presence of two discrete morphotypes (i.e. shallow type < 5 m and deep type > 17 m). A discriminant function analysis based on a priori univariate and multivariate analyses (which separated the colonies in morphotypes) correctly classified 93% of the colonies for each environment. Light, water motion and sediment transport might influence the distribution of the two morphotypes. Reaction norms of morphological characters of colonies reciprocally transplanted showed gradual significant changes through the 15 months of transplantation. Sclerites of shallow water colonies became larger when transplanted to deeper environments and vice versa, but neither of the two transplanted groups overlapped with the residents' morphology. Genetic analysis of mitochondrial and nuclear genes suggested that such discrete morphology and non-overlapping phenotypic plasticity is correlated with the presence of two independent evolutionary lineages. The distribution of the lineages is non-random and may be related to adaptational responses of each lineage to the environmental demands of each habitat.</p> <p>Conclusion</p> <p>The extensive distribution and ample morphological variation of <it>Eunicea flexuosa </it>corresponds to two distinct genetic lineages with narrower distributions and more rigid phenotypic plasticity than the original description. The accepted description <it>sensu </it>Bayer (1961) of <it>E. flexuosa </it>is a complex of at least two distinct genetic lineages, adapted to different habitats and do not exchange genetic material despite living in sympatry. The present study highlights the importance of correctly defining species, because the unknowingly use of species complexes can overestimate geographical distribution, population abundance, and physiological tolerance.</p

The evolution of euhermaphroditism in caridean shrimps: a molecular perspective of sexual systems and systematics

<p>Abstract</p> <p>Background</p> <p>The hippolytid genus <it>Lysmata </it>is characterized by simultaneous hermaphroditism, a very rare sexual system among Decapoda. Specialized cleaning behavior is reported in a few pair-living species; these life history traits vary within the genus. Unfortunately, the systematics of <it>Lysmata </it>and the Hippolytidae itself are in contention, making it difficult to examine these taxa for trends in life history traits. A phylogeny of <it>Lysmata </it>and related taxa is needed, to clarify their evolutionary relationships and the origin of their unique sexual pattern. In this study, we present a molecular phylogenetic analysis among species of <it>Lysmata</it>, related genera, and several putative hippolytids. The analysis is based upon DNA sequences of two genes, 16S mtDNA and nuclear 28S rRNA. Phylogenetic trees were estimated using Bayesian Inference, Maximum Likelihood, and Maximum Parsimony.</p> <p>Results</p> <p>Phylogenetic analysis of 29 species of <it>Lysmata</it>, eight genera of Hippolytidae and two genera of Barbouriidae based on a single (16S, 28S) and combined gene approach (16S+28S) indicates that three groups of <it>Lysmata </it>differentiate according to antennular morphology: (1) <it>Lysmata</it>, having a multi-segmented accessory branch, (2) <it>Hippolysmata </it>(prior to Chace 1972), with a one-segmented accessory branch, and (3) a third group of <it>Lysmata </it>outliers, with one-segmented unguiform accessory branch, and close affinity to the genera <it>Exhippolysmata </it>and <it>Lysmatella</it>. The monophyly of the clade bearing a multi-segmented accessory branch is robust. Within the short accessory branch clade, species with specialized cleaning behaviors form a monophyletic clade, however, the integrity of the clade was sensitive to alignment criteria. Other hippolytid and barbouriid genera used in the analysis are basal to these three groups, including one displaying simultaneous hermaphroditism (<it>Parhippolyte</it>). The two barbouriid species occur in a separate clade, but among hippolytid taxa.</p> <p>Conclusions</p> <p>The data support the historical morphological division of <it>Lysmata </it>into clades based on accessory branch morphology. The position of the "cleaner" shrimps, indicates that specialized cleaning behavior is a derived trait. The topologies of the cladograms support the monophyly of the barbouriids, but do not support their elevation to familial status. Taxa ancestral to the genus <it>Lysmata </it>display simultaneous hermaphroditism, suggesting that this life history trait evolved outside the genus <it>Lysmata</it>.</p

Vitamin K Deficiency and Vascular Calcification. Is There Any Evidence about Its Impact on Coronary Artery Disease?

Nowadays cardiovascular disease remain globally the leading cause of mortality. Coronary artery disease is the predominant clinical entity related to fatal cardiovascular events, while its development is mostly associated with progressive atherosclerosis of the vessels combined with gradual vascular calcification. It is well described and understood that vascular calcification is strongly associated with the occurrence of CVD and increased mortality rates. Therefore, it is essential to understand the metabolic pathways leading to its formation in order to develop effective therapies. A group of vitamin-k dependent proteins seems to play a significant role on the prevention of the arterial wall. Several past studies have shown that in cases of vitamin-k deficiency the process of vessel calcification is accelerated. Vitamin-k depletion and high levels of uncarboxylated and dephosphorylated forms of the aforementioned proteins are considered as important factors that contribute significantly to this rapid progression. Promising studies are giving the stimulus for further research in the field of vitamin-k supplementation and the suspension of vascular calcification

Perspective Chapter: Transcatheter Aortic Valve Implantation (TAVI)-Anesthetic Considerations

Aortic valvular stenosis remains the most common weakening valvular heart lesion. Many high-risk patients cannot tolerate surgery. Transcatheter aortic valve implantation (TAVI) is an emergent alternative technique. General and local anesthesia plus sedation are both valid alternative techniques that can be titrated according to patient characteristics. Hemodynamic management is the main concern of intraoperative anesthesiological management. Preprocedural, multidisciplinary assessment of the patient is essential prior to TAVI and should include a full anesthetic evaluation. TAVI offers a number of advantages to patients and medical teams, but there are still accompanying important complications and anesthesiological risks

Perspective Chapter: Moderate Aortic Stenosis and Heart Failure With Reduced Ejection Fraction; Early Replacement or Conservative Treatment?

Aortic stenosis (AS) is the most common valve lesion among the continuously aging population with serious effect on the left ventricular ejection fraction (LVEF). If left untreated, it is associated with serious complications such as heart failure (HF), pulmonary hypertension, thromboembolic events, and even sudden death. Early diagnosis and treatment is of outmost importance to avoid the above complications but also to maintain the patient’s normal heart function. Echocardiography is the key examination that assesses the severity of the stenosis, valve calcification, left ventricular (LV) function, and wall thickness. Also new imaging methods such as cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) help in assessing the severity of aortic valve stenosis when echocardiography has limitations. Based on the categorization of the severity of the stenosis, its treatment is determined. Although things are clear in cases of asymptomatic disease and severe stenosis, this is not the case in moderate disease. Experts and clinical trials do not define clearly which cases can be treated conservatively and which need surgical or transcatheter intervention. The purpose of this article is to gather all the latest data on the treatment of moderate aortic stenosis, especially in patients with heart failure and low ejection fraction

Surgical Outcomes in Syndromic Tetralogy of Fallot: A Systematic Review and Evidence Quality Assessment

Tetralogy of Fallot (ToF) is one of the most common cyanotic congenital heart defects. We sought to summarize all available data regarding the epidemiology and perioperative outcomes of syndromic ToF patients. A PRISMA-compliant systematic literature review of PubMed and Cochrane Library was performed. Twelve original studies were included. The incidence of syndromic ToF was 15.3% (n = 549/3597). The most prevalent genetic syndromes were 22q11.2 deletion (47.8%; 95% CI 43.4–52.2) and trisomy 21 (41.9%; 95% CI 37.7–46.3). Complete surgical repair was performed in 75.2% of the patients (n = 161/214; 95% CI 69.0–80.1) and staged repair in 24.8% (n = 53/214; 95 CI 19.4–30.9). Relief of RVOT obstruction was performed with transannular patch in 64.7% (n = 79/122; 95% CI 55.9–72.7) of the patients, pulmonary valve-sparing technique in 17.2% (n = 21/122; 95% CI 11.5–24.9), and RV-PA conduit in 18.0% (n = 22/122; 95% CI 12.1–25.9). Pleural effusions were the most common postoperative complications (n = 28/549; 5.1%; 95% CI 3.5–7.3). Reoperations were performed in 4.4% (n = 24/549; 95% CI 2.9–6.4) of the patients. All-cause mortality rate was 9.8% (n = 51/521; 95% CI 7.5–12.7). Genetic syndromes are seen in approximately 15% of ToF patients. Long-term survival exceeds 90%, suggesting that surgical management should be dictated by anatomy regardless of genetics

Percutaneous tracheostomy-beware of the thyroidea-ima artery

Percutaneous tracheostomy is a minimally invasive operation performed in patients, in order to provide an air passage through the windpipe. A rare cause of severe bleeding during such operation is the injury of the thyroidea-ima artery. This case report presents a patient with hemorrhage after thyroidea-ima injury during percutaneous dilatational tracheostomy. Surgeons should always be aware of such anatomic variation, in order to prevent urgent sternotomy

A new genus of Parastenocarididae (Copepoda, Harpacticoida) from the Tocantins River basin (Goiás, Brazil), and a phylogenetic analysis of the Parastenocaridinae

Eirinicaris antonioi gen. et sp. n. (Parastenocaridinae) is described from the Brazilian rocky savannas, an ecosystem under heavy anthropogenic pressure. The subfamily is distributed worldwide, with representatives in Africa, Asia, Australia, Europe, and North America. This is the first time a non-Remaneicaris Parastenocaridinae is described from a Neotropical region indicating that Parastenocaridinae species were already present in a vast geographical area, before the split of the Gondwana. The new taxon is included within the subfamily Parastenocaridinae based on the following characters: 1) segments 5, 6, and 7 of the male antennules forming a functional unit for clasping the female; 2) segment 7 with small process at the inner margin, forming an incipient "pocket-knife" structure with segment 6; 3) last segment pointing medially when closed; 4) the endopod of female leg 3 one-segmented and spiniform, without distal seta; 5) the apophysis and terminal seta of the exopod of male leg 3 are fused; 6) the genital field is rectangular and much broader than the height in the female; 7) the group of three lateral setae I, II, and III of the furca and the dorsal seta are situated at the same level in the female; and 8) the basis of leg 1 has an inner seta. The new taxon can be distinguished from all other Parastenocaridinae genera by the unique sexually dimorphic telson and furca. In the male, the dorsal seta is inserted at the midlength of the furca and setae I, II, and III are displaced anteroventrally. A phylogenetic analysis of the subfamily Parastenocaridinae is given based on the description of the type species of each genus and available descriptions of all Parastenocaridinae species. Eirinicaris gen. n. is the sister taxon of a clade formed by Kinnecaris and Monodicaris, sharing with them the long male and female leg 5 with a long spiniform process, and with Kinnecaris, a distal pore on the spiniform process. © Paulo H.C. Corgosinho et al

Fish, Coral, and Sponge Assemblages Associated With Altiphotic and Mesophotic Reefs Along the Guánica Biosphere Reserve Continental Shelf Edge, Southwest Puerto Rico

The benthic and fish communities of the central portion of the Guánica, Puerto Rico shelf edge were studied to determine species abundance, distributions and species overlap between two depth stratifications, 20 and 45 m, at eight sites. A total of 67 fish species belonging to 21 families were identified. Similar species richness estimates were observed between depths, though fish assemblage composition differed significantly, with observable changes in feeding guild contributions of herbivore and omnivore (20 m) to a deeper assemblage composed of piscivores and planktivores (45 m). Coral assemblages consisted of 31 species at 20 m and 11 species at 45 m, accounting for 17.0% (±1.76 SE) and 2.6% (±0.89 SE) benthic cover for the altiphotic and mesophotic surveys, respectively. The altiphotic and mesophotic coral reef communities support different scleractinian coral assemblages with minimal species overlap. Altiphotic surveys of sponges yielded a higher species richness than mesophotic, with 60 and 54 species respectively, and an overall total of 71 species identified from both depths, with 45 species overlapping (63.0%). The percent cover of sponges surveyed at altiphotic reefs accounted for 9.0% (±1.04 SE), while the percent cover of sponges surveyed at mesophotic reefs was 14.0% (±1.96 SE). Our data show fish, coral, and sponge assemblages are differentiated between 20 and 45 m along the Guánica shelf edge offshore of the Guánica Biosphere Reserve. This study represents the first observations for species distributions of adjacent altiphotic and mesophotic coral reef habitats along the Guánica shelf edge, as well as provides an annotated species list of the local sponge fauna. Combined, these results highlight the need for continued environmental stewardship and conservation in the area