Four new species of Typhlocharis (baetica group) (Coleoptera: Carabidae: Anillini) from southwestern Iberian Peninsula with notes on their biogeographical and morphological implications

Four new species of Typhlocharis (Carabidae: Anillini) are described from the southwest of the Iberian Peninsula, assigned to the baetica species group. T. prima sp.n. , T. secunda sp.n. and T. tertia sp.n. (from La Palma del Condado, Huelva, Spain) are syntopic, and T. quarta sp.n. (from Barrancos, Beja, Portugal) is the first species of the group with umbilicate series 4 + 4. They represent, respectively, the southernmost and westernmost distribution data for the group. The baetica group remains well defined and includes ten species. The diagnosis is simplified, with the confirmation that many morphological features characteristic of this group are widespread within the genus. The defining character is the presence of denticles in apical margin of elytra, not associated to the seventh stria or to the elytral suture. The new species provide morphological data that suggest the baetica and silvanoides groups are closely related. Distribution of both groups in the south of the Iberian Peninsula and the presence of morphological characters that are considered plesiomorphic are coherent with the hypothesis of betic‐riffain origin of the genus. They also support the hypothesis of easy alteration of the umbilicate pattern between closely related species and the independent origin of apical denticles in the group compared with those present in other species of the genus. The presence of three well‐differentiated size ranges in syntopic populations suggest ecological diversification to avoid interspecific competition.     

Postzygotic isolation drives genomic speciation between highly cryptic Hypocnemis antbirds from Amazonia

How species evolve reproductive isolation in the species-rich Amazon basin is poorly understood in vertebrates. Here, we sequenced a reference genome and used a genome-wide sample of SNPs to analyze a hybrid zone between two highly cryptic species of Hypocnemis warbling-antbirds—the Rondonia warbling-antbird (H. ochrogyna) and Spix's warbling-antbird (H. striata)—in a headwater region of southern Amazonia. We found that both species commonly hybridize, producing F₁s and a variety of backcrosses with each species but we detected only one F₂-like hybrid. Patterns of heterozygosity, hybrid index, and interchromosomal linkage disequilibrium in hybrid populations closely match expectations under strong postzygotic isolation. Hybrid zone width (15.4 km) was much narrower than expected (211 km) indicating strong selection against hybrids. A remarkably high degree of concordance in cline centers and widths across loci, and a lack of reduced interspecific F_st between populations close to versus far from the contact zone, suggest that genetic incompatibilities have rendered most of the genome immune to introgression. These results support intrinsic postzygotic isolation as a driver of speciation in a moderately young cryptic species pair from the Amazon and suggest that species richness of the Amazon may be grossly underestimated.     

Seed coat anatomy ofCeratozamia mexicana (Cycadales)

The seed coat furnishes protection with a thick cuticle, tannin cells, mucilage, and a hard sclerotesta. The external layer of the seed coat is a sarcotesta; a thick cuticle covers the external walls of its epidermal cells. This epidermis bears stomates and, in the early stages, trichomes. The subepidermal cells have druses. Starch grains are abundant in the sarcotesta from June through August, but they disappear during dispersal in September. The parenchyma is interrupted by mucilage canals lined by epithelial cells. Tannin cells are found in the sarcotesta, sclerotesta, and pachychalaza. Ten sectors of an areole in the sclerotesta around the micropyle may correspond to the tips of the integumentary segments in some fossil plants, such asGenomosperma kidstonii.

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Resumen  La cubierta seminal le imparte protección a la semilla mediante una cutícula gruesa, células de taninos, mucílago, y una esclerotesta dura. La capa externa de la cubierta seminal es la sarcotesta; una cutícula gruesa cubre las paredes externas de las células epidérmicas. Esta epidermis presenta estomas y, en etapas tempranas, tricomas. Cuando la esclerotesta se endurece, los tricomas desaparecen. Las células subepidérmicas presentan drusas. En la sarcotesta los granos de almidón son abundantes desde junio hasta agosto, pero desaparecen durante la dispersión en septiembre. El parénquima se interrumpe por canales de mucílago forrados por células epiteliales. Las células de taninos se encuentran en la sarcotesta, esclerotesta, y paquicálaza. Diez sectores de una areola en la esclerotesta alrededor del micrópilo podrían corresponder a los apéndices del tegumento en algunas plantas fósiles, comoGenomosperma kidstonii.

     

From pathogen genomes to host plant processes: the power of plant parasitic oomycetes

Recent pathogenomic research on plant parasitic oomycete effector function and plant host responses has resulted in major conceptual advances in plant pathology, which has been possible thanks to the availability of genome sequences.     

Comparison of Botrytis cinerea populations isolated from two open-field cultivated host plants

The necrotrophic fungus Botrytis cinerea is reported to infect more than 220 host plants worldwide. In phylogenetical–taxonomical terms, the pathogen is considered a complex of two cryptic species, group I and group II. We sampled populations of B. cinerea on sympatric strawberry and raspberry cultivars in the North-East of Hungary for three years during flowering and the harvest period. Four hundred and ninety group II B. cinerea isolates were analyzed for the current study. Three different data sets were generated: (i) PCR-RFLP patterns of the ADP-ATP translocase and nitrate reductase genes, (ii) MSB1 minisatellite sequence data, and (iii) the fragment sizes of five microsatellite loci. The structures of the different populations were similar as indicated by Nei's gene diversity and haplotype diversity. The F statistics (F_st, G_st), and the gene flow indicated ongoing differentiation within sympatric populations. The population genetic parameters were influenced by polymorphisms within the three data sets as assessed using Bayesian algorithms. Data Mining analysis pointed towards the five microsatellite loci as the most defining markers to study differentiation in the 490 isolates. The results suggest the occurrence of host-specific, sympatric divergence of generalist phytoparasites in perennial hosts.     

A Predictive Model for Corticosteroid Response in Individual Patients with MS Relapses

Objectives

To derive a simple predictive model to guide the use of corticosteroids in patients with relapsing remitting MS suffering an acute relapse.

Materials and Methods

We analysed individual patient randomised controlled trial data (n=98) using a binary logistic regression model based on age, gender, baseline disability scores [physician-observed: expanded disability status scale (EDSS) and patient reported: multiple sclerosis impact scale 29 (MSIS-29)], and the time intervals between symptom onset or referral and treatment.

Results

Based on two a priori selected cut-off points (improvement in EDSS ≥ 0.5 and ≥ 1.0), we found that variables which predicted better response to corticosteroids after 6 weeks were younger age and lower MSIS-29 physical score at the time of relapse (model fit 71.2% - 73.1%).

Conclusions

This pilot study suggests two clinical variables which may predict the majority of the response to corticosteroid treatment in patients undergoing an MS relapse. The study is limited in being able to clearly distinguish factors associated with treatment response or spontaneous recovery and needs to be replicated in a larger prospective study.     

Vertical Movements and Patterns in Diving Behavior of Whale Sharks as Revealed by Pop-Up Satellite Tags in the Eastern Gulf of Mexico

The whale shark (Rhincodon typus) is a wide-ranging, filter-feeding species typically observed at or near the surface. This shark’s sub-surface habits and behaviors have only begun to be revealed in recent years through the use of archival and satellite tagging technology. We attached pop-up satellite archival transmitting tags to 35 whale sharks in the southeastern Gulf of Mexico off the Yucatan Peninsula from 2003–2012 and three tags to whale sharks in the northeastern Gulf off Florida in 2010, to examine these sharks’ long-term movement patterns and gain insight into the underlying factors influencing their vertical habitat selection. Archived data were received from 31 tags deployed on sharks of both sexes with total lengths of 5.5–9 m. Nine of these tags were physically recovered facilitating a detailed long-term view into the sharks’ vertical movements. Whale sharks feeding inshore on fish eggs off the northeast Yucatan Peninsula demonstrated reverse diel vertical migration, with extended periods of surface swimming beginning at sunrise followed by an abrupt change in the mid-afternoon to regular vertical oscillations, a pattern that continued overnight. When in oceanic waters, sharks spent about 95% of their time within epipelagic depths (<200 m) but regularly undertook very deep (“extreme”) dives (>500 m) that largely occurred during daytime or twilight hours (max. depth recorded 1,928 m), had V-shaped depth-time profiles, and comprised more rapid descents (0.68 m sec^-1) than ascents (0.50 m sec^-1). Nearly half of these extreme dives had descent profiles with brief but conspicuous changes in vertical direction at a mean depth of 475 m. We hypothesize these stutter steps represent foraging events within the deep scattering layer, however, the extreme dives may have additional functions. Overall, our results demonstrate complex and dynamic patterns of habitat utilization for R. typus that appear to be in response to changing biotic and abiotic conditions influencing the distribution and abundance of their prey.     

Plastidic Phosphoglucose Isomerase Is an Important Determinant of Starch Accumulation in Mesophyll Cells,Growth, Photosynthetic Capacity,and Biosynthesis of Plastidic Cytokinins in Arabidopsis

Phosphoglucose isomerase (PGI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. It is involved in glycolysis and in the regeneration of glucose-6-P molecules in the oxidative pentose phosphate pathway (OPPP). In chloroplasts of illuminated mesophyll cells PGI also connects the Calvin-Benson cycle with the starch biosynthetic pathway. In this work we isolated pgi1-3, a mutant totally lacking pPGI activity as a consequence of aberrant intron splicing of the pPGI encoding gene, PGI1. Starch content in pgi1-3 source leaves was ca. 10-15% of that of wild type (WT) leaves, which was similar to that of leaves of pgi1-2, a T-DNA insertion pPGI null mutant. Starch deficiency of pgi1 leaves could be reverted by the introduction of a sex1 null mutation impeding β-amylolytic starch breakdown. Although previous studies showed that starch granules of pgi1-2 leaves are restricted to both bundle sheath cells adjacent to the mesophyll and stomata guard cells, microscopy analyses carried out in this work revealed the presence of starch granules in the chloroplasts of pgi1-2 and pgi1-3 mesophyll cells. RT-PCR analyses showed high expression levels of plastidic and extra-plastidic β-amylase encoding genes in pgi1 leaves, which was accompanied by increased β-amylase activity. Both pgi1-2 and pgi1-3 mutants displayed slow growth and reduced photosynthetic capacity phenotypes even under continuous light conditions. Metabolic analyses revealed that the adenylate energy charge and the NAD(P)H/NAD(P) ratios in pgi1 leaves were lower than those of WT leaves. These analyses also revealed that the content of plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP)-pathway derived cytokinins (CKs) in pgi1 leaves were exceedingly lower than in WT leaves. Noteworthy, exogenous application of CKs largely reverted the low starch content phenotype of pgi1 leaves. The overall data show that pPGI is an important determinant of photosynthesis, energy status, growth and starch accumulation in mesophyll cells likely as a consequence of its involvement in the production of OPPP/glycolysis intermediates necessary for the synthesis of plastidic MEP-pathway derived hormones such as CKs.