Female Atrium Research Articles

Enhanced Ca2+-Driven Arrhythmogenic Events in Female Patients With AtrialFibrillation: Insights From Computational Modeling.

Substantial sex-based differences have been reported in atrial fibrillation (AF), but the underlying mechanisms are poorly understood. This study sought to gain a mechanistic understanding of Ca2+-handling disturbances and Ca2+-driven arrhythmogenic events in male vs female atrial cardiomyocytes and establish their responses to Ca2+-targeted interventions. We integrated reported sex differences and AF-associated changes (ie, expression and phosphorylation of Ca2+-handling proteins, cardiomyocyte ultrastructural characteristics, and dimensions) into our human atrial cardiomyocyte model that couples electrophysiology with spatially detailed Ca2+-handling processes. Sex-specific responses of atrial cardiomyocytes to arrhythmia-provoking protocols and Ca2+-targeted interventions were evaluated. Simulated quiescent cardiomyocytes showed increased incidence of Ca2+ sparks in female vs male myocytes inAF, in agreement with previous experimental reports. Additionally, our female model exhibited elevated propensity to develop pacing-induced spontaneous Ca2+ releases (SCRs) and augmented beat-to-beat variability in action potential (AP)-elicited Ca2+ transients compared with the male model. Sensitivity analysis uncovered distinct arrhythmogenic contributions of each component involved in sex and/or AF alterations. Specifically, increased ryanodine receptor phosphorylation emerged as the major SCR contributor in female AF cardiomyocytes, whereas reduced L-type Ca2+ current was protective against SCRs for male AF cardiomyocytes. Furthermore, simulated Ca2+-targeted interventions identified potential strategies (eg, t-tubule restoration, and inhibition of ryanodine receptor and sarcoplasmic/endoplasmic reticulum Ca2⁺-ATPase) to attenuate Ca2+-driven arrhythmogenic events in women, and revealed enhanced efficacy when applied in combination. Sex-specific modeling uncovers increased Ca2+-driven arrhythmogenic events in female vs male atria inAF, and suggests combined Ca2+-targeted interventions are promising therapeutic approaches in women.

Abstract Mo057: Computational Modeling Reveals Enhanced Ca 2+ -Driven Arrhythmias in Female Patients with Atrial Fibrillation

Background and Aim: Substantial sex-based differences have been reported in atrial fibrillation (AF), with female patients experiencing worse symptoms, more complications from treatment, and greater risk of stroke and mortality. Recent studies revealed sex-specific alterations in AF-associated Ca 2+ dysregulation, whereby female myocytes more frequently exhibit proarrhythmic Ca 2+ -driven instabilities compared to male myocytes. Here, we aim to obtain a mechanistic understanding of the Ca 2+ -handling disturbances and Ca 2+ -driven arrhythmogenic events in males vs females and establish their responses to Ca 2+ -targeted interventions. Methods and Results: We incorporated known sex differences and AF-associated changes in the expression and phosphorylation of key Ca 2+ -handling proteins and in ultrastructural properties and dimensions of atrial myocytes into our recently developed 3D atrial myocyte model that couples electrophysiology with spatially detailed Ca 2+ -handling processes. Simulations show increased incidence of Ca 2+ sparks in female vs male myocytes in AF, in agreement with previous experimental reports. Additionally, our female model exhibited elevated propensity to developing pacing-induced spontaneous Ca 2+ releases (SCRs, Figure 1A,B ) and augmented beat-to-beat variability in action potential (AP)-elicited Ca 2+ transients compared with the male model ( Figure 1C ). Parameter sensitivity analysis uncovered precise arrhythmogenic contributions of each component that was implicated in sex and/or AF alterations ( Figure 2 ). Specifically, increased ryanodine receptor phosphorylation in female AF myocytes emerged as the major SCR contributor, while reduced L-type Ca 2+ current was protective against SCRs for male AF myocytes. Furthermore, simulations of Ca 2+ -targeted interventions identified potential strategies to attenuate Ca 2+ -driven arrhythmogenic events in female atria (e.g., t-tubule restoration, and inhibition of ryanodine receptor and sarcoplasmic/endoplasmic reticulum Ca 2+ -ATPase), and revealed enhanced efficacy when applied in combination. Conclusions: Our sex-specific computational models of human atrial myocytes uncover the increased female propensity to Ca 2+ -driven arrhythmogenic events vs male in AF, and identify combined Ca 2+ -targeted interventions as promising approaches to treat AF in female patients. Our study establishes that AF treatment may benefit from sex-dependent strategies informed by sex-specific mechanisms.

Male and female atria exhibit distinct acute electrophysiological responses to sex steroids

The electrophysiological properties of the hearts of women and men are different. These differences are at least partly mediated by the actions of circulating estrogens and androgens on the cardiomyocytes. Experimentally, much of our understanding in this field is based on studies focusing on ventricular tissue, with considerably less known in the context of atrial electrophysiology. The aim of this investigation was to compare the electrophysiological properties of male and female atria and assess responses to acute sex steroid exposure. Age-matched adult male and female C57BL/6 mice were anesthetized (4 % isoflurane) and left atria isolated. Atria were loaded with Di-4-ANEPPS voltage sensitive dye and optical mapping performed to assess action potential duration (APD; at 10 %, 20 %, 30 %, 50 %, and 70 % repolarization) and conduction velocity in the presence of 1 nM and 100 nM 17β-estradiol or testosterone. Male and female left atria demonstrated similar baseline action potential duration and conduction velocity, with significantly greater APD70 spatial heterogeneity evident in females. 17β-estradiol prolonged action potential duration in both sexes – an effect that was augmented in females. Atrial conduction was slowed in the presence of 100 nM 17β-estradiol in both males and females. Testosterone prolonged action potential duration in males only and did not modulate conduction velocity in either sex. This study provides novel insights into male and female atrial electrophysiology and its regulation by sex steroids. As systemic sex steroid levels change and intra-cardiac estrogen synthesis capacity increases with aging, these actions may have an increasingly important role in determining atrial arrhythmia vulnerability.

Assessing the effect of breed, age, and sex on muscarinic receptor distribution in atria and ventricles of turkeys

Atrial and ventricular myocardium from young (6-wk-old), young adult (3-6-mo-old), and aged (14-15-mo-old) meat-type (B.U.T. Big 6) and wild-type (Cröllwitzer) turkeys were used to study the influence of age and sex on cholinergic muscarinic receptors using [3H]-N-methyl-scopolamine (3H-NMS) binding studies. In both breeds, saturation experiments indicated the presence of regional-, sex-, and age-related differences in the density of cholinergic muscarinic receptors (Bmax), that is, a decrease or increase. Except for right atria, Bmax was decreased in both male and female B.U.T. Big 6 hearts with increasing age. Similarly, a negative correlation between Bmax and age could be seen in female and male atria of Cröllwitzer turkeys, while positive correlation could be seen in right and left ventricles of male, and only right ventricles of female Cröllwitzer turkeys. The affinity of the receptor (KD) was not affected by age, sex and breed. In all cardiac chamber tissues, the M2-subtype was shown to be predominant followed by the M3-subtype and to a lesser extent the M1-subtype. Aspects of this age-dependent remodeling of the heart differ between sexes, resulting in maladaptive changes in older turkeys with a high degree of frailty. These observations may help explain why males and females are susceptible to different cardiovascular diseases as they age and why frail older adults are most often affected by these diseases.

Bundles of Sperm: Structural Diversity in Scorpion Sperm Packages Illuminates Evolution of Insemination in an Ancient Lineage

The spermatozoa of scorpions are often bundled together, forming a type of sperm conjugation known as a sperm package. Sperm packages may be found inside the testes and seminal vesicles but vanish in the female atrium, leaving free spermatozoa. Previous studies, based on a limited number of taxa, suggested a diversity of sperm package morphology across the order Scorpiones C.L. Koch, 1850. However, the sperm packages of most scorpion taxa remained unknown. The present study provides the first systematic survey of sperm package morphology across the order, covering 89 exemplar species in 66 genera and 19 families representing all suprafamilial ranks, with a more detailed investigation of the family Bothriuridae Simon, 1880. Whereas all exemplar species of scorpions exhibit sperm packages, Buthida Soleglad and Fet, 2003, including Chaerilidae Pocock, 1893, and most Buthidae C.L. Koch, 1837, present unorganized sperm or loosely organized bundles. Although the details vary, three main types of sperm packages may be recognized in all other families: single folded; straight; and multiple folded. Subtypes may be identified according to general shape and folding patterns, mainly among sperm packages that are folded multiple times. Single-folded sperm packages are the most common type observed in the order. Although most sperm packages lack a covering, a conspicuous secretion sheath may be evident, e.g., in some Chactidae Pocock, 1893. Sperm packages vary in length from 112–354 µm and bent sperm packages are not necessarily longer than straight sperm packages. Four exemplar species of Bothriuridae reveal that variation in sperm count within a single sperm package is consistent with the count derived in spermatogenesis. The diversity of sperm packages suggests a path from free spermatozoa, via bent sperm packages, to other forms. Sperm packages may aid in the transport, cooperation, competition, and survival of spermatozoa. The diverse morphology, function, and evolution of sperm packages merit further investigation.

Two new land planarian species (Platyhelminthes: Tricladida) from the Cerrado biome in southwestern Brazil

Most Neotropical land flatworm species are known from areas of the Atlantic Forest. Herein, we describe two new land planarian species from areas of semideciduous forest in the Cerrado biome in southwestern Brazil. Paraba aurantia Marques & Leal-Zanchet, sp. nov. can be distinguished from its congeners by the wide black median band on the dorsum, eyes occupying almost the entire dorsal surface, prostatic vesicle twisted and asymmetrical with proximal portions forked, and female atrium with an ample lumen lined by a low epithelium with stratified appearance. Pasipha liviae Marques & Leal-Zanchet, sp. nov. shows a narrow longitudinal dorsal stripe, collar-shaped pharynx, and prostatic vesicle with a pear-shaped proximal portion and a globose distal portion separated by a constriction. In addition, P. liviae can be distinguished from its congeners by molecular analyses from the cytochrome c oxidase subunit I gene (COI). Phylogenetic analyses suggest that P. liviae is closely related to P. hauseri, which occurs in areas of semidseciduous forest in southern Brazil.

A new genus and two new species of land planarians (Platyhelminthes: Tricladida: Geoplanidae) from Southern Chile

ABSTRACT The paper describes the new land planarian genus Mapuplana gen. nov. from Chile, on the basis of the two new species Mapuplana guttulata sp. nov. and M. fjordica sp. nov. The genus Mapuplana is mainly characterised by two putative apomorphies: a subneural parenchymal musculature consisting of diagonal decussate muscle fibres; and a blind duct opening sideways into the female atrium. The new species are very similar to each other in their general anatomy and differ only in details in the pattern of dorsal colouration, the relative distance between mouth and gonopore, the relative thickness of the ventral cutaneous musculature, the orientation of the gonoduct, and the shape of the female atrium. http://www.zoobank.org/urn:lsid:zoobank.org:pub:120AC180-D4AC-433F-B3A0-BB96C6962DB4

A new genus of land planarian (Platyhelminthes, Geoplanidae) for a new ‘blind’ species

The morphological and molecular (mitochondrial cytochrome c oxidase subunit I, COI) characterization of a new species of the subfamily Geoplaninae (Geoplanidae) supports the erection of a new genus, Anophthalmoplana gen. nov. The most remarkable feature of Anophthalmoplana horticola sp. nov. is the absence of eyes, a feature so far only recorded in one species of Geoplaninae, Geobia subterranea. Other features of the species are: a narrow, ribbon-shaped body; a gonopore near the posterior tip; a creeping sole almost as wide as body width; cylindrical pharynx; voluminous extrabulbar prostatic vesicle; protrusible penis papilla occupying the whole male atrium; a common ovovitelline duct dorsal to the female atrium; the atrium being lined by an epithelium with a stratified appearance. Based on the mtDNA phylogeny, the specimens studied here form a separate clade from the genus Geobia, thus contradicting its inclusion in this genus or any other of the subfamily Geoplaninae. These results reinforce the morphological differences observed, regarding internal anatomy, from Geobia and other members of Geoplaninae. http://zoobank.org/urn:lsid:zoobank.org:pub:317A4055-BCC8-4B89-A9DC-F96F98E803A5

RNA-seq profiling of the atrial transcriptome reveals gender-specific patterns and interactions with atrial fibrillation and heart failure

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): TRAIN-HEART Innovative Training Network, funded by the European Union’s Horizon 2020 research and innovation program (under the Marie Sklodowska-Curie grant agreement no. 813716) Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly (CATCH ME), funded by the European Union’s Horizon 2020 research and innovation program (under the grant agreement no. 633196) Background Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with heart failure (HF) and stroke. Clinical and experimental data from previous studies suggest gender differences in mechanisms and phenotypes of AF: women may have more atrial fibrosis, worse outcomes after catheter ablation, and some women carry a higher risk for thromboembolic complications than men. The molecular mechanisms underlying these differences are still poorly understood. Methods Gender-based transcriptional patterns were assessed using paired-end, directional RNA sequencing data generated from atrial tissue biopsies in 199 patients either in sinus rhythm or with paroxysmal or persistent AF as part of the CATCH-ME project. Transcript counts were compared between genders separately in the left and right atria using the DESeq2 package in R. The models were adjusted for potential sources of confounding (age, atrial fibrillation status, heart failure status and sequencing batch). Interaction models were implemented using DESeq2 to compare gender*morbidity interactions for persistent AF and HF. Significance was assessed using likelihood ratio tests comparing models with and without the interaction terms. Results with an adjusted P-value 0.05 were considered significant and utilized for subsequent downstream assessments. Differentially expressed (DE) genes were tested for enrichment of gene ontology (GO) terms and KEGG pathways using the WebGestalt toolkit. Results Transcriptome-wide profiling across the cohort identified 33 sex-differentiated genes in the left atria and 51 in the right atrial samples, with 21 of these showing bilateral differences. Interestingly, 36 (44%) of the results from these analyses were comprised of non-coding transcripts, including long non-coding RNAs (lncRNAs), antisense RNAs and pseudogenes. GO and pathway enrichment analyses for these genes revealed their involvement in critical pathways such as the complement and coagulation cascades and RNA transport. Interaction analyses between gender and AF identified two genes (MPP2 & GNAS-AS1) that were differentially transcribed in the right atria and one gene (MYL2) that was DE in the left atria by gender in persistent AF samples. A similar analysis comparing gender*HF morbidity also revealed evidence of DE. Four transcripts (HLA-DQB1-AS1, EIF1AY, UTY and ZFY-AS1) showed gender-specific differences in expression by HF status in left atria, while HLA-DQB1-AS1 was differentially regulated by gender and HF status in right atrial samples. Conclusions These RNA-seq analyses provide novel insights into gender-related differences in the transcriptional landscape of right and left adult human atrial appendages. Moreover, interaction analyses identified three genes DE in female atria in persistent AF and four DE genes in female atria in heart failure, providing a molecular anchor for the observed differences in atrial diseases phenotypes between men and women.

Mating-regulated atrial proteases control reinsemination rates in Anopheles gambiae females

Anopheles gambiae mosquitoes are the most important vectors of human malaria. The reproductive success of these mosquitoes relies on a single copulation event after which the majority of females become permanently refractory to further mating. This refractory behavior is at least partially mediated by the male-synthetized steroid hormone 20-hydroxyecdysone (20E), which is packaged together with other seminal secretions into a gelatinous mating plug and transferred to the female atrium during mating. In this study, we show that two 20E-regulated chymotrypsin-like serine proteases specifically expressed in the reproductive tract of An. gambiae females play an important role in modulating the female susceptibility to mating. Silencing these proteases by RNA interference impairs correct plug processing and slows down the release of the steroid hormone 20E from the mating plug. In turn, depleting one of these proteases, the Mating Regulated Atrial Protease 1 (MatRAP1), reduces female refractoriness to further copulation, so that a significant proportion of females mate again. Microscopy analysis reveals that MatRAP1 is localized on a previously undetected peritrophic matrix-like structure surrounding the mating plug. These data provide novel insight into the molecular mechanisms shaping the post-mating biology of these important malaria vectors.

Three new Neotropical species and a new genus of land flatworms (Platyhelminthes, Geoplaninae)

Three new Neotropical land planarians (Platyhelminthes, Tricladida, Geoplaninae) from the Brazilian Atlantic forest are described. Obama apiguara Oliveira, Almeida & Carbayo sp. nov. presents glandular fossae opening through dorsal epithelium, a structure not documented previously among land flatworms. Paraba tata Bolonhezi, Lago-Barcia & Carbayo sp. nov., is characterized by a prostatic vesicle horizontal with an inconspicuous bifurcate portion, a penis papilla as long as male atrium and a female genital duct projected from the postero-dorsal section of the female atrium. The third new species is distinctive in the extraordinarily thick muscle surrounding the prostatic vesicle, a finger-shaped penis papilla, and a dilated female genital cavity. These attributes stands the species apart from all members of Geoplaninae and Piima ata Carbayo gen. et sp. nov. is proposed.

The morphology of mating plugs and its formation in scorpions: Implications for intersexual participation.

Mating plugs have been proposed as a mechanism that has evolved to avoid sperm competition. Their structure and composition vary across taxa and are related to the effectiveness of its function. This effectiveness could be related to different evolutionary interests of the sexes. Urophonius brachycentrus and Urophonius achalensis (Scorpiones, Bothriuridae) are highly suitable species to study mating plugs because both are monandrous species with specific morphological and physiological responses in the female's genitalia. Here, we analyze (a) the morphology and fine structure of the mating plugs of both species, (b) the site of production in males and the formation process of the mating plug, and (c) the changes that it undergoes over time in the female's reproductive tract. In both species, a complex mating plug obliterates the female's genital aperture and fills the genital atrium. We observed considerable interspecific variation in the mating plug morphology. A mating hemi-plug was found surrounding the capsular lobes of the hemispermatophore, which could have a mixed composition (involving portions of the hemispermatophore and glandular products). The glandular portion was transferred in a semi-solid state filling the female's genital atrium and then hardening. Changes that the plug undergoes in the female's genitalia (darkening and increase of the "distal" area of the plug) indicate a participation of the female to the formation of this type of plug. Our study provides new insights into the plugging phenomenon in scorpions, and we discussed the adaptive significance as a post-copulatory mechanism to avoid sperm competition.

Two new species of land planarians (Platyhelminthes, Tricladida, Geoplanidae) from protected areas in the southern extreme of the Paranaense Rainforest, Argentina

Here, we describe two new flatworm species of the genera Obama Carbayo et al., 2013 and Notogynaphallia Ogren & Kawakatsu, 1990 (Geoplaninae) found in riverine forests of central-eastern Argentina. Obama maculatentis sp. nov., which is about 50 mm in length, is characterized by black olive pigmentation on the dorsum, with two irregular rows of black spots, and light grey ventral surface. The eyes, with clear halos, extend to the dorsal surface. The foremost features of the copulatory apparatus include dorsal testes anterior to ovaries, extrabulbar prostatic vesicle with forked proximal portion, protrusible penis, male atrium with a large dorsal fold separating it from the female atrium, ovovitelline ducts ascending at the level of the gonopore, common ovovitelline duct dorsal to the distal portion of the female atrium, female canal ventro-anteriorly flexed, and female atrium with narrow lumen. Notogynaphallia fortuita sp. nov., which is about 30 mm in length, is characterized by beige ground pigmentation with tiny darker spots, cephalic region saffron yellow, and ventral surface light grey. The eyes, with small clear halos, extend to the dorsal surface. Regarding the internal anatomy, this new species shows parenchymatic musculature not organized in discrete layers, testes arising near the anterior end of the body, distal sperm ducts traversing the common muscle coat and joining in a short common sperm duct. The areas in which the land planarians were found represent the southernmost latitudes with representatives of the Interior Atlantic Forest (Paranaense Rainforest) biota, hence their biogeographical and conservation significance.

Acute Oestradiol Slows Conduction in Male, but not Female, Murine Left Atria

Pericardial adipose accumulation increases atrial fibrillation risk; however, the underlying mechanisms are not well understood. We have demonstrated that pericardial adipose expresses aromatase, indicating capacity to locally synthesise oestrogens. In Langendorff-perfused mouse hearts, atrial arrhythmia incidence correlated with the total aromatase capacity of this adipose depot, and exogenous oestradiol increased arrhythmia vulnerability. The aim of this study was to determine how acute administration of oestrogens modulate cardiac electrophysiology in male and female cardiomyocyte monolayers and intact left atria. Microelectrode array (MEA)-seeded neonatal rat ventricular myocytes (NRVMs) were exposed to increasing concentrations of oestradiol (0–100 nM) and synchronous field potentials recorded. Optical action potentials were measured from isolated adult mouse left atria stained with Di-4-ANEPPS, electrically paced and superfused with increasing concentrations of oestradiol (n = 4–10). NRVM conduction velocity (CV) and field potential duration were unaffected by acute oestradiol. Acute oestradiol prolonged action potential duration at 70% repolarisation (APD70) in both male (ΔAPD70, 100 nM oestradiol vs vehicle: 5.8 ± 0.9 ms vs 1.6 ± 1.6 ms; P = 0.037) and female atria (7.6 ± 1.0 ms vs 3.9 ± 0.9 ms; P = 0.045). A lower oestradiol concentration slowed CV in male (ΔCV, 1 nM oestradiol vs vehicle: −9.2 ± 1.8 cm s−1 vs −1.1 ± 2.7 cm s−1; P = 0.007), but not female atria (ΔCV: −2.4 ± 2.0 cm s−1 vs 0.05 ± 3.2 cm s−1; P = 0.79). Slowed action potential propagation and prolonged repolarisation are two key mechanisms underlying reentrant and triggered arrhythmias, respectively. These rapid responses to acute oestrogen administration indicate non-genomic influences on cardiomyocyte electrophysiology and may be mediated by stimulation of oestrogen receptor signalling pathways.

Coming out in a harsh environment: a new genus and species for a land flatworm (Platyhelminthes: Tricladida) occurring in a ferruginous cave from the Brazilian savanna.

Faunal inventories in ferruginous caves from an area belonging to the Brazilian savanna (Cerrado phytophysiognomy), on the eastern margin of the Serra do Espinhaço Plateau, in southeastern Brazil, have revealed the occurrence of land flatworms. Herein, a flatworm sampled in such subterranean environment is described as a new genus and species of the Neotropical subfamily Geoplaninae, Difroehlichia elenae gen. nov., sp. nov. The new genus shows rare features within Geoplaninae, namely sub-cylindrical body, poorly developed sub-epidermal musculature and a narrow creeping sole. Some features, such as a small body and a broad sensory margin in the anterior region of the body, as well as the fact that the holotype showed signs of recent copula, may indicate an adaptation to the subterranean environment, probably representing a troglophile. Difroehlichia elenae is characterized by an almost homogeneous dark brown pigmentation over dorsal surface and body margins, a short cylindrical pharynx, and a tubular and unforked intrabulbar prostatic vesicle, among other features. The holotype shows a secondary male copulatory organ located immediately behind the primary one, both communicating with the female atrium and gonopore canal. Since the species seems to have low abundance and restricted distribution and its type-locality is affected by mining activities, major concern arises regarding its conservation.

A transgenic tool to assess Anopheles mating competitiveness in the field

BackgroundMalaria parasites, transmitted by the bite of an anopheline mosquito, pose an immense public health burden on many tropical and subtropical regions. The most important malaria vectors in sub-Saharan Africa are mosquitoes of the Anopheles gambiae complex including An. gambiae (sensu stricto). Given the increasing rates of insecticide resistance in these mosquitoes, alternative control strategies based on the release of genetically modified males are being evaluated to stop transmission by these disease vectors. These strategies rely on the mating competitiveness of release males, however currently there is no method to determine male mating success without sacrificing the female. Interestingly, unlike other insects, during mating An. gambiae males transfer their male accessory glands (MAGs) seminal secretions as a coagulated mating plug which is deposited in the female atrium.ResultsHere we exploit this male reproductive feature and validate the use of a MAG-specific promoter to fluorescently label the mating plug and visualize the occurrence of insemination in vivo. We used the promoter region of the major mating plug protein, Plugin, to control the expression of a Plugin-tdTomato (PluTo) fusion protein, hypothesizing that this fusion protein could be incorporated into the plug for sexual transfer to the female. Anopheles gambiae PluTo transgenic males showed strong red fluorescence specifically in the MAGs and with a pattern closely matching endogenous Plugin expression. Moreover, the fusion protein was integrated into the mating plug and transferred to the female atrium during mating where it could be visualized microscopically in vivo without sacrificing the female. PluTo males were equally as competitive at mating as wild type males, and females mated to these males did not show any reduction in reproductive fitness.ConclusionThe validation of the first MAG-specific promoter in transgenic An. gambiae facilitates the live detection of successful insemination hours after copulation has occurred. This provides a valuable tool for the assessment of male mating competitiveness not only in laboratory experiments but also in semi-field and field studies aimed at testing the feasibility of releasing genetically modified mosquitoes for disease control.

Searching for shelter in a ferruginous cave? A new species of Pasipha from a plateau in the Brazilian savanna (Platyhelminthes, Tricladida).

In a fauna survey in the eastern margin of Serra do Espinhaço Plateau, in an area belonging to the Brazilian savanna (Cerrado phytophysiognomy), a land flatworm was sampled in a ferruginous cave. Anatomical and histological analyses indicated that it belongs to a new species of the genus Pasipha, which is herein described. The new species shows an almost homogenous dark brown dorsal pigmentation, eyes spreading over the dorsal surface, a collar-shaped pharynx, and a prostatic vesicle with two portions separated by a canal. It differs from similar species mainly by anatomical and histological details of the ejaculatory duct, as well as male and female atria. The flatworm shows no troglomorphic traits and was collected once in the entrance zone of the cave. Hence, despite representing the first land flatworm species described from a Neotropical cave, we consider that its occurrence in the cave is probably occasional, using it as a shelter.

Body doubles: an integrative taxonomic approach reveals new sibling species of land planarians

Records of cryptic species have continued to emerge in the scientific literature, often revealed by the use of molecular phylogenetic analyses in an integrative taxonomic approach. This study addresses a group of four striped flatworms from the genus Pasipha Ogren & Kawakatsu, showing a pale median stripe on a dark dorsal surface. Based on morphological and molecular analyses from the cytochrome c oxidase subunit I gene (COI), we establish that we are dealing with sibling species that are closely related to P. brevilineata Leal-Zanchet, Rossi & Alvarenga, 2012, a recently described species with a similar colour pattern. Thus, we describe three of the studied flatworms as new species and propose one new unconfirmed candidate species based on molecular data. In addition, sequence analysis revealed 40 nucleotide autapomorphies supporting the species studied herein. Considering anatomical and histological features, the three new species are differentiated from their congeners mainly by details of the copulatory apparatus, such as the occurrence of an epithelium of pseudostratified appearance lining the female atrium and the shape and position of the proximal portion of the prostatic vesicle.

Increasing diversity of land planarians (Platyhelminthes: Geoplanidae) in the Interior Atlantic Forest with the description of two new species and new records from Argentina.

Here, we describe two new species of land planarians of the genera Pasipha and Imbira from the Atlantic Forest of Argentina: Pasipha quirogai sp. nov. and Imbira negrita sp. nov. Their external features and internal anatomy distinguish them from their congeners. Pasipha quirogai sp. nov. is about 40mm long, characterized by brown beige dorsal pigmentation with a golden yellow median band and thin graphite black para-median stripes, cylindrical pharynx, extrabulbar prostatic vesicle with paired proximal portion, male atrium with small folds in its proximal part, and female canal opening into the dorso-caudal wall of the female atrium. Imbira negrita sp. nov. is about 110mm long, with jet black dorsal pigmentation, pharynx collar-type, short female canal opening in the postero-dorsal portion of the female atrium, and epithelial lining of female atrium with stratified appearance. We also provide exhaustive descriptions of Geoplana quagga, Obama ladislavii, and Paraba multicolor, all recorded for the first time in Argentina, by analysing anatomical features of taxonomic relevance. In addition, we improve the description of G. quagga, mainly regarding the musculature, secretory cells, and the copulatory apparatus.

First report of the genus Cratera (Platyhelminthes, Geoplanidae) in Argentina, with description of a new species and comments on the species of the genus.

A new species of land planarians of the genus Cratera is described. Cratera viridimaculata sp. n. was recorded in the Atlantic Forest Ecoregion, in north-eastern Argentina, and represents the first report of the genus Cratera outside Brazil. The new species is about 50 mm in length and externally characterized by a color pattern consisting of a light green olive pigmentation on the dorsum, stippled with dark gray fine spots, and dorsal eyes. Other features regarding the internal anatomy are the presence of a glandular margin, Cutaneous Muscular Index (CMI) of 10–13%, pharynx cylindrical, prostatic vesicle extrabulbar, tubular and C-shaped, with a proximal bifurcated portion, penis papilla protrusible with ejaculatory duct widened in its distal portion, and female atrium funnel-shaped. The new species is compared and discussed with its congeners.