Divergence and gene flow history at two large chromosomal inversions underlying ecotype differentiation in the long-snouted seahorse

Chromosomal inversions can play an important role in divergence and reproductive isolation by building and maintaining distinct allelic combinations between evolutionary lineages. Alternatively, they can take the form of balanced polymorphisms that segregate within populations until one arrangement becomes fixed. Many questions remain about how inversion polymorphisms arise, how they are maintained over the long term, and ultimately, whether and how they contribute to speciation. The long-snouted seahorse (Hippocampus guttulatus) is genetically subdivided into geographic lineages and marine-lagoon ecotypes, with shared structural variation underlying lineage and ecotype divergence. Here, we aim to characterize structural variants and to reconstruct their history and suspected role in ecotype formation. We generated a near chromosome-level genome assembly and described genome-wide patterns of diversity and divergence through the analysis of 112 whole-genome sequences from Atlantic, Mediterranean, and Black Sea populations. By also analysing linked-read sequencing data, we found evidence for two chromosomal inversions that were several megabases in length and showed contrasting allele frequency patterns between lineages and ecotypes across the species range. We reveal that these inversions represent ancient intraspecific polymorphisms, one likely being maintained by divergent selection and the other by pseudo-overdominance. A possible selective coupling between the two inversions was further supported by the absence of specific haplotype combinations and a putative functional interaction between the two inversions in reproduction. Lastly, we detected gene flux eroding divergence between inverted alleles at varying levels for the two inversions, with a likely impact on their dynamics and contribution to divergence and speciation.

Structural variation of the 3-acetamido-4,5,6-trihydroxyazepane iminosugar through epimerization and C-alkylation leads to low micromolar HexAB and NagZ inhibitors

We report the synthesis of seven-membered iminosugars derived from a 3S-acetamido-4R,5R,6S-trihydroxyazepane scaffold and their evaluation as inhibitors of functionally related exo-N-acetylhexosaminidases including human O-GlcNAcase (OGA), human lysosomal β-hexosaminidase (HexAB), and Escherichia coli NagZ. Capitalizing on the flexibility of azepanes and the active site tolerances of hexosaminidases, we explore the effects of epimerization of stereocenters at C-3, C-5 and C-6 and C-alkylation at the C-2 or C-7 positions. Accordingly, epimerization at C-6 (L-ido) and at C-5 (D-galacto) led to selective HexAB inhibitors whereas introduction of a propyl group at C-7 on the C-3 epimer furnished a potent NagZ inhibitor.

Deciphering the molecular mechanisms of mother-to-egg immune protection in the mealworm beetle Tenebrio molitor

In a number of species, individuals exposed to pathogens can mount an immune response and transmit this immunological experience to their offspring, thereby protecting them against persistent threats. Such vertical transfer of immunity, named trans-generational immune priming (TGIP), has been described in both vertebrates and invertebrates. Although increasingly studied during the last decade, the mechanisms underlying TGIP in invertebrates are still elusive, especially those protecting the earliest offspring life stage, i.e. the embryo developing in the egg. In the present study, we combined different proteomic and transcriptomic approaches to determine whether mothers transfer a "signal" (such as fragments of infecting bacteria), mRNA and/or protein/peptide effectors to protect their eggs against two natural bacterial pathogens, namely the Gram-positive Bacillus thuringiensis and the Gram-negative Serratia entomophila. By taking the mealworm beetle Tenebrio molitor as a biological model, our results suggest that eggs are mainly protected by an active direct transfer of a restricted number of immune proteins and of antimicrobial peptides. In contrast, the present data do not support the involvement of mRNA transfer while the transmission of a "signal", if it happens, is marginal and only occurs within 24h after maternal exposure to bacteria. This work exemplifies how combining global approaches helps to disentangle the different scenarios of a complex trait, providing a comprehensive characterization of TGIP mechanisms in T. molitor. It also paves the way for future alike studies focusing on TGIP in a wide range of invertebrates and vertebrates to identify additional candidates that could be specific to TGIP and to investigate whether the TGIP mechanisms found herein are specific or common to all insect species.

Prenatal microarray comparative genomic hybridization: Experience from the two first years of activity at the Lyon university-hospital

OBJECTIVES

This study aims to describe how microarray comparative genomic hybridization (aCGH) has shifted to become a prenatal diagnosis tool at the Lyon university-hospital.

MATERIALS AND METHODS

This retrospective study included all patients who were referred in the 3 pluridisciplinary centers for prenatal diagnosis of the Lyon university-hospital and who received a prenatal aCGH between June 2013 and June 2015. aCGH was systematically performed in parallel with a karyotype, using the PréCytoNEM array design.

RESULTS

A total of 260 microarrays were performed for the following indications: 249 abnormal ultrasounds (95.8%), 7 characterizations of chromosomal rearrangements (2.7%), and 4 twins with no abnormal ultrasounds (1.5%). With a resolution of 1 mega base, we found 235 normal results (90.4%), 23 abnormal results (8.8%) and 2 non-returns (0.8%). For the chromosomal rearrangements visible on the karyotype, aCGH identified all of the 12 unbalanced rearrangements and did not identify the 2 balanced rearrangements. Among the fetuses with normal karyotypes, 11 showed abnormal microarray results, corresponding to unbalanced cryptic chromosomal rearrangements (4.2%).

CONCLUSION

Transferring aCGH to a prenatal diagnosis at the Lyon university-hospital has increased the detection rate of chromosomal abnormalities by 4.2% compared to the single karyotype.

Multiprobe Study of the Solid Electrolyte Interphase on Silicon-Based Electrodes in Full-Cell Configuration

The failure mechanism of silicon-based electrodes has been studied only in a half-cell configuration so far. Here, a combination of ⁷Li, ¹⁹F MAS NMR, XPS, TOF-SIMS, and STEM-EELS, provides an in-depth characterization of the solid electrolyte interphase (SEI) formation on the surface of silicon and its evolution upon aging and cycling with LiNi_1/3Mn_1/3Co_1/3O₂ as the positive electrode in a full Li-ion cell configuration. This multiprobe approach indicates that the electrolyte degradation process observed in the case of full Li-ion cells exhibits many similarities to what has been observed in the case of half-cells in previous works, in particular during the early stages of the cycling. Like in the case of Si/Li half-cells, the development of the inorganic part of the SEI mostly occurs during the early stage of cycling while an incessant degradation of the organic solvents of the electrolyte occurs upon cycling. However, for extended cycling, all the lithium available for cycling is consumed because of parasitic reactions and is either trapped in an intermediate part of the SEI or in the electrolyte. This nevertheless does not prevent the further degradation of the organic electrolyte solvents, leading to the formation of lithium-free organic degradation products at the extreme surface of the SEI. At this point, without any available lithium left, the cell cannot function properly anymore. Cycled positive and negative electrodes do not show any sign of particles disconnection or clogging of their porosity by electrolyte degradation products and can still function in half-cell configuration. The failure mechanism for full Li-ion cells appears then very different from that known for half-cells and is clearly due to a lack of cyclable lithium because of parasitic reactions occurring before the accumulation of electrolyte degradation products clogs the porosity of the composite electrode or disconnects the active material particles.

Minimum spread of the new Swedish variant of Chlamydia trachomatis and distribution of C. trachomatis ompA genotypes in three geographically distant areas of Spain, 2011-2012

PURPOSE

The aim of this study was to determine the presence of the new Swedish Chlamydia trachomatis (C. trachomatis) variant (nvCT) and the distribution of C. trachomatis ompA genotypes in three geographically distant regions of Spain.

METHODS

The genotypes of strains causing 624 episodes of infection (January 2011-September 2012) were studied using a nested PCR that amplifies a fragment of the ompA gene, followed by sequencing. To detect nvCT, a real-time PCR was used that amplifies a fragment of the cryptic plasmid with a 377 base pair deletion, which identifies the nvCT.

RESULTS AND CONCLUSION

The ompA genotype was identified in 565 (90.5%) episodes. Eleven genotypes were detected, of which nine were found in all three regions. Only one nvCT strain was detected (0.4%), despite the predominance of genotype E (41%). Other frequent genotypes were genotypes D (19%), F (13%), G (11 %), and J (7%). Genotype L2b, causing lymphogranuloma venereum, was detected in men who have sex with men (MSM) in all three regions. Genotypes E and F were more frequent in women and heterosexual men, and genotypes D, G, J and L2b in MSM. In men, the main factor causing differences in the distribution of C. trachomatis was sexual behavior (MSM versus heterosexual men), while the distribution of C. trachomatis genotypes was similar in women and heterosexual men.

[Ovarian tissue vitrification: Cortex and whole ovary in sheep]

OBJECTIVE

The aim of this study was to evaluate a cryopreservation technique by vitrification of cortex or whole ovaries in sheep, using two cryoprotectant solutions: VS1 and VS4 and to study their physical properties to avoid ice crystallisation by vitrification of whole sheep ovaries permeated with a cryoprotectant solution.

ANIMALS AND METHODS

From 6-month-old ewes, whole sheep ovaries with their vascular pedicles were collected at the slaughterhouse or at the veterinary school and prepared for cryoprotectant toxicity tests and freezing procedure. Follicle viability was measured by trypan blue test and histological examination of ovary. The hemi-ovarian cortex was stored in liquid nitrogen. Four to six weeks after the first laparotomy, the controlateral ovary was removed and the vitrified-warmed hemi-ovary was sutured. Thermal properties of a cryoprotectant solution called VS4 (critical cooling rates [Vccr], vitreous transition temperature [Tg], end of melting temperature [Tm]) were measured by differential scanning calorimetry.

RESULTS

No significant difference in follicle viability or normal follicle rates was observed between ovarian cortex exposed or non-exposed to cryoprotectant solutions. Nor was any significant difference observed before and after vitrification. Three pregnancies occurred, from which four lambs were born after autografts of vitrified ovarian cortex. With whole ovary, the decrease in the number of normal follicles was lower when frozen-thawed ovaries were treated with VS4 (P = 0.04). There were less nuclear anomalies (P = 0.02). The Vccr of VS4 has been estimated to be 14.3+/-1.1 degrees C/min and Tg was -125.0+/-0.2 degrees C. Because the penetration of cryoprotectants was very low, Vccr was very high and the cooling speed did not allow cortex to vitrify.

DISCUSSION AND CONCLUSIONS

Cryopreservation of cortex or whole ovary by vitrification seems a promising technique in reproductive medicine. The best histologic results were obtained with the VS4 cryoprotectant when whole ovary was vitrified.

Reproducibility of transvaginal three-dimensional endometrial volume measurements with virtual organ computer-aided analysis (VOCAL) during ovarian stimulation

OBJECTIVE

To calculate inter- and intraobserver reliabilities for three-dimensional endometrial volume measurements during in vitro fertilization using virtual organ computer-aided analysis (VOCAL).

PATIENTS AND METHODS

Three-dimensional ultrasound measurements of the endometrium using VOCAL software were performed on the day of oocyte retrieval in each of 79 consecutive patients undergoing in vitro fertilization or intracytoplasmic sperm injection. Endometrial volume was calculated every 15 degrees and every 30 degrees by two different observers in order to determine the reproducibility of the technique.

RESULTS

Intraobserver reliability for the 15 degrees measurements was 0.97 for both observers; for the 30 degrees measurements, it was 0.93 for one observer and 0.96 for the other. Interobserver reliability was 0.80 for the endometrial volumes calculated every 15 degrees and 0.83 for the volumes calculated every 30 degrees. The intra- and interobserver measurement agreement showed good reproducibility. However, the volumes calculated every 15 degrees were more accurate because the means of differences were close to zero.

CONCLUSION

VOCAL provides a reproducible method for the estimation of the endometrial volume.

[Propionibacterium acnes infection in patients with CSF shunts]

BACKGROUND AND METHODS

Propionibacterium acnes is a common inhabitant of human skin rarely associated with clinical disease. However it has been recognized as a cause of shunt and postneurosurgical infections. From January 1992 to June 1995, 5,947 cerebrospinal fluid (CSF) samples were cultured in our laboratory. We carried out a clinical-epidemiological study in patients where P. acnes was isolated from CSF.

RESULTS

P, acnes was isolated from 11 CSF samples which corresponded to 7 episodes of shunt infection in 6 patients. Five were men; the mean age was 28.5 years. The mean time of onset of infection after the last shunt manipulation was 104 weeks. All of them presented symptomatology associated with infection. All episodes but one, where P. acnes was considered to be a contaminant, were treated with systemic and intraventricular antibiotic therapy and complete shunt removal. Four patients made an uneventful recovery and two patients died due to causes not directly related with the infection.

CONCLUSIONS

P. acnes is frequently isolated in patients with shunt infections. Its isolation must be seriously considered not viewed as a contaminant without an exhaustive investigation.

[Clinical characteristics and epidemiologic study of a listeriosis outbreak in Grand Canary]

BACKGROUND AND METHODS

Human infections caused by Listeria monocytogenes often present as sporadic cases without any epidemiological relationship among them; however they also appear as outbreaks that are usually detected by an increase in the number of cases diagnosed by hospitals of the geographic area. Between December 1991 and May 1993, twenty four cases of listeriosis were detected in three hospitals of Las Palmas de Gran Canaria; and they were classified as an outbreak. Our report describes its clinical, epidemiological and microbiological aspects.

RESULTS AND CONCLUSIONS

Twenty four cases of listeriosis were diagnosed, 12 occurred in pregnant women or neonates (5 and 7 respectively) and 12 in non pregnant adults. All adult infections were community-acquired. The incidence rate was, for the epidemic area, 76.3 cases per million population during the period considered (18 months). Among non pregnant adults, 9/12 patients had some underlying disease and 9/12 presented CNS affection (meningitis and/or cerebritis). In the group of pregnant women, 4 cases occurred in the second trimester and fetal loss was caused; one case was detected in the third trimester and four weeks later the patient delivered an unaffected infant. All cases of neonatal listeriosis presented as early-onset sepsis. Of the 24 strains of L. monocytogenes, 21 were serotype 4, two were serotype 1 and one was not typeable. Strains from 12 patients were available for epidemiological analysis, seven of which corresponded to the same pattern and there were three more different patterns.

The impact on breastfeeding and pregnancy status of household contraceptive distribution in rural Haiti

This paper presents data from an experimental project which distributed oral contraceptives, foam, and condoms to households in three rural areas of Haiti between January 1978 and March 1980. The contraceptive distribution had little apparent impact on traditional, prolonged breastfeeding patterns, and the percentage of women pregnant after eight months of field operations declined over 35 per cent in the two areas where contraceptive acceptance and use were highest. (Am J Public Health 1982; 72:825-838.)