Malacofauna Cuaternaria del litoral norte de Santa Cruz (Patagonia, Argentina)

The molluscan content from three “marine terraces” (TM) preserved along 250 km of the Santa Cruz province provided 49 molluscan taxa (33 Gastropoda and 16 Bivalvia) and the first Quaternary records for Ataxocerithium pullum, Crepidula protea, C. aculeata, Adelomelon ferrusacii, Brachidontes rodriguezi, Aequipecten tehuelchus, Ostrea tehuelcha, and Solen tehuelchus. The mollusca assemblages suggest typical marine nearshore conditions similar to the adjacent modern littoral (Southwestern Atlantic), with mostly hard substrates, shallow and cold waters. The TMVI (+ 5-15 m a.s.l., ca. 8-1.2 ka A.P.) is mainly characterized by dominance of Brachidontes spp., Nacella spp. and Mytilus edulis, associated with Siphonaria lessoni. No evidence has been found for the TMVI of clear biotic responses or strong palaeobiogeographic effects during the time span of the Climatic Optimum (“Hypsithermal”, mid-Holocene) which has been documented for other coastal areas northward in Argentina, down to ca. 44-45° S. Scarce differences distinguish the TMV (+ 15-30 m a.s.l., ca. 108-137 ka A.P., MIS5?) and TMIV (+ 20-30 m a.s.l., ca. 242 ka A.P.) regarding the Holocene and the modern littoral. Within the TMV, Clausinella, Eurhomalea, Solen tehuelchus and Brachidontes cf. darwinianus (typically in warmer waters) are exclusive; in the TMIV, Trophon, Buccinanops, Brachidontes and Pectinidae are characteristic. Predominance of Trophon spp. (typically in cold Magallanic waters) in modern samples vs. scarcity or absence in the TM suggest slightly lower modern SST. Several taxonomic similitudes with the Pacific Sudamerican coast (e.g., Fissurella,Nacella, Tegula, Crepidula, Trochita, and Acanthina) could respond to cold currents helping cold-water immigrants to join southern Southamerican Atlantic after the opening of the Drake Passage.     

Complementary influences of co-occurring physical ecosystem engineers on species richness: insights from a Patagonian rocky shore

Structural modification of the environment by physical ecosystem engineers often allows for the occurrence of species that are not able to establish in unengineered habitats, thus leading to increased species richness at the landscape-level (i.e., areas encompassing engineered and unengineered habitats). Unlike previous studies that focused on the contribution of a single engineering species to landscape-level species richness, this study evaluates whether co-occurring engineers—i.e., intertidal mussels (primarily Perumytilus purpuratus) and rock boring bivalves (Lithophaga patagonica)—contribute to landscape-level species richness in a similar or complementary way. Our results show that both mussel and L. patagonica patches harbor a substantial number of invertebrate species in addition to those occurring in the unenegineered rock substrate. However, the distinctive habitat patches created by each engineer add exclusive subsets of species to the study area, which implies that mussel and L. patagonica patches contribute complementarily to overall species richness in our intertidal landscape. Here we postulate that complementary engineering effects on landscape-level species richness will occur when the engineered patches structurally differ from each other and, thus, vary in their relative ability to modulate two or more abiotic conditions and/or resources that prevent species establishment in the unengineered state. In spite of its inherently small spatial scale (500 m), our study highlights the potential for complementary engineering impacts at the larger scales that are usually implied in biodiversity conservation and management (tens to hundreds of kilometers) and outlines a simple conceptual basis and approach to address them.     

An investigation of conventional microbial culture for the Naja atra bite wound,and the comparison between culture-based 16S Sanger sequencing and 16S metagenomics of the snake oropharyngeal bacterial microbiota

Naja atra is a major venomous snake found in Taiwan. The bite of this snake causes extensive wound necrosis or necrotizing soft tissue infection. Conventional microbial culture-based techniques may fail to identify potential human pathogens and render antibiotics ineffective in the management of wound infection. Therefore, we evaluated 16S Sanger sequencing and next-generation sequencing (NGS) to identify bacterial species in the oropharynx of N. atra. Using conventional microbial culture methods and the VITEK 2 system, we isolated nine species from snakebite wounds. On the basis of the 16S Sanger sequencing of bacterial clones from agar plates, we identified 18 bacterial species in the oropharynx of N. atra, including Morganella morganii, Proteus vulgaris, and Proteus mirabilis, which were also present in the infected bite wound. Using NGS of 16S metagenomics, we uncovered more than 286 bacterial species in the oropharynx of N. atra. In addition, the bacterial species identified using 16S Sanger sequencing accounted for only 2% of those identified through NGS of 16S metagenomics. The bacterial microbiota of the oropharynx of N. atra were modeled better using NGS of 16S metagenomics compared to microbial culture-based techniques. Stenotrophomonas maltophilia, Acinetobacter baumannii, and Proteus penneri were also identified in the NGS of 16S metagenomics. Understanding the bacterial microbiota that are native to the oropharynx of N. atra, in addition to the bite wound, may have additional therapeutic implications regarding empiric antibiotic selection for managing N. atra bites.     

New insights into Oculina patagonica coral diseases and their associated Vibrio spp. communities

Bleaching of Oculina patagonica has been extensively studied in the Eastern Mediterranean Sea, although no studies have been carried out in the Western basin. In 1996 Vibrio mediterranei was reported as the causative agent of bleaching in O. patagonica but it has not been related to bleached or healthy corals since 2003, suggesting that it was no longer involved in bleaching of O. patagonica. In an attempt to clarify the relationship between Vibrio spp., seawater temperature and coral diseases, as well as to investigate the putative differences between Eastern and Western Mediterranean basins, we have analysed the seasonal patterns of the culturable Vibrio spp. assemblages associated with healthy and diseased O. patagonica colonies. Two sampling points located in the Spanish Mediterranean coast were chosen for this study: Alicante Harbour and the Marine Reserve of Tabarca. A complex and dynamic assemblage of Vibrio spp. was present in O. patagonica along the whole year and under different environmental conditions and coral health status. While some Vibrio spp. were detected all year around in corals, the known pathogens V. mediteranei and V. coralliilyticus were only present in diseased specimens. The pathogenic potential of these bacteria was studied by experimental infection under laboratory conditions. Both vibrios caused diseased signs from 24 °C, being higher and faster at 28 °C. Unexpectedly, the co-inoculation of these two Vibrio species seemed to have a synergistic pathogenic effect over O. patagonica, as disease signs were readily observed at temperatures at which bleaching is not normally observed.     

Studies on the interactions of sperm with the surface of the sea urchin egg

We have examined the relationship between sperm adhesion and fertilization in the cross species insemination of Arbacia punctulata eggs by Strongylocentrotus purpuratus sperm. As previously reported (Kinsey et al., 1980) the addition of S. purpuratus egg jelly results in induction of the acrosome reaction in sperm and significant numbers of S. purpuratus sperm adhere to A. punctulata eggs. However, in the absence of S. purpuratus egg jelly, S. purpuratus sperm fail to bind to A. punctulata eggs. Although at least 200 S. purpuratus sperm bind to an A. punctulata egg in the presence of S. purpuratus jelly, less than 8% of the eggs are fertilized. The adhesion of S. purpuratus sperm meets the same functional criteria as homologous A. punctulata sperm-egg adhesion. Electron microscopy shows that S. purpuratus sperm that have undergone the acrosome reaction adhere to A. punctulata eggs by their bindin-coated acrosomal process in a manner that is morphologically identical to that observed with homologous A. punctulata sperm. We have also compared the ability of S. purpuratus and A. punctulata sperm to fuse and fertilize with A. punctulata eggs after removal of the vitelline layer. Using high levels of sperm of either species, heterologous as well as homologous fertilization is readily detectable. Under these conditions, where stable binding is not demonstrable, there is no difference in the ability of S. purpuratus and A. punctulata sperm to fertilize A. punctulata eggs. These observations suggest that the failure of S. purpuratus sperm to fertilize A. punctulata eggs under normal conditions may be due to their inability to penetrate the vitelline layer so that they can fuse with the egg plasma membrane. In relation to the possible mechanism of vitelline layer penetration, we have also investigated the mode of action of chymostatin, an inhibitor of chymotrypsin that has been reported to inhibit fertilization of sea urchin eggs (Hoshi et al., 1979). Our findings suggest that the fertilization inhibitory activity of chymostatin is not related to its antichymotrypsin activity. Rather, it appears that this inhibition is due to the induction of an abnormal acrosome reaction in sperm that precludes formation of the acrosome process.     

Species composition,richness, and distribution of marine bivalve molluscs in Bahía de Mazatlán,México

We describe the composition and distribution of bivalve molluscs from the sandy and rocky intertidal and the shallow subtidal environments of Bahía de Mazatlán, México. The bivalve fauna of the bay is represented by 89 living species in 28 families, including 37 new records and four range extensions: Lithophaga hastasia, Adula soleniformis, Mactrellona subalata, and Strigilla ervilia. The number of species increases from the upper (44) and lower intertidal (53) to the shallow subtidal (76), but only 11 (17%) have a wide distribution in the bay (i.e., found in all sampling sites and environments). The bivalve assemblages are composed of four main life forms: 27 epifaunal species, 26 infaunal, 16 semi-infaunal, and 20 endolithic. A taxonomic distinctness analysis identified the sampling sites and environments that contribute the most to the taxonomic diversity (species to suborder categories) of the bay. The present work increased significantly (31%) to 132 species previous inventories of bivalves of Bahía de Mazatlán. These species represent 34% of the bivalve diversity of the southern Golfo de California and approximately 15% of the Eastern Tropical Pacific region.     

Marker-assisted pyramiding of bacterial blight and gall midge resistance genes into RPHR-1005, the restorer line of the popular rice hybrid DRRH-3

Bacterial blight (BB) of rice caused by the pathogen Xanthomonas oryzae pv. oryzae and the insect gall midge (GM) (Orseolia oryzae) are two major constraints of rice production. The present study was carried out to improve RPHR-1005, a stable restorer line of the fine-grain-type rice hybrid DRRH-3, for BB and GM resistance through marker-assisted backcross breeding (MABB). Two major GM resistance genes, Gm4 and Gm8, and a major BB resistance gene, Xa21, were selected as target genes for transfer to RPHR-1005. Two sets of backcrosses were carried out to combine either Xa21 + Gm4 or Xa21+ Gm8 into RPHR-1005 using breeding lines in the genetic background of ISM possessing either Gm4 or Gm8 along with Xa21. Foreground selection was performed for Xa21, Gm4, Gm8, and the major fertility restorer genes Rf3 and Rf4 using gene-specific markers, while 61 polymorphic simple sequence repeat (SSR) markers were used for background selection and marker-assisted backcrossing was continued until BC₂ generation. A promising homozygous backcross-derived plant at the BC₂F₂ generation possessing Xa21 + Gm4, and another possessing Xa21 + Gm8, were intercrossed to stack the target resistance genes. At ICF ₄ (inter-crossed F₄) , three promising lines possessing the three target resistance genes in a homozygous condition along with fine-grain type, complete fertility restoration, and better panicle exsertion than RPHR-1005 have been identified. Among these, a single line, # RPIC-16-65-125, showed better yield, was highly resistant to BB and GM, was of medium–slender grain type, and had complete fertility restoration along with better panicle exsertion and taller plant type than RPHR-1005. This is the first report of combining resistance against BB and GM in the genetic background of a hybrid rice parental line.     

SNP assay to detect the ‘Hyuuga’ red-brown lesion resistance gene for Asian soybean rust

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi Syd., has the potential to become a serious threat to soybean, Glycine max L. Merr., production in the USA. A novel rust resistance gene, Rpp?(Hyuuga), from the Japanese soybean cultivar Hyuuga has been identified and mapped to soybean chromosome 6 (Gm06). Our objectives were to fine-map the Rpp?(Hyuuga) gene and develop a high-throughput single nucleotide polymorphism (SNP) assay to detect this ASR resistance gene. The integration of recombination events from two different soybean populations and the ASR reaction data indicates that the Rpp?(Hyuuga) locus is located in a region of approximately 371 kb between STS70887 and STS70923 on chromosome Gm06. A set of 32 ancestral genotypes which is predicted to contain 95% of the alleles present in current elite North American breeding populations and the sources of the previously reported ASR resistance genes (Rpp1, Rpp2, Rpp3, Rpp4, Rpp5, and rpp5) were genotyped with five SNP markers. We developed a SimpleProbe assay based on melting curve analysis for SNP06-44058 which is tighly linked to the Rpp?(Hyuuga) gene. This SNP assay can differentiate plants/lines that are homozygous/homogeneous or heterozygous/heterogeneous for the resistant and susceptible alleles at the Rpp?(Hyuuga) locus.     

Cloning and sequencing of genes encoding malonate decarboxylase in Acinetobacter calcoaceticus

Malonate decarboxylase from Acinetobacter calcoaceticus was isolated and characterized (Kim, Y.S., Byun, H.S., J. Biol. Chem. 269 (1994) 29636–29641), and its subunits were reanalyzed recently to be α, β, γ, and δ. The genes for the subunits, MdcA (548 a.a.), B (295 a.a.), C (238 a.a.), and D (102 a.a.), of the enzyme have been cloned by using oligonucleotide primers deduced from amino acid sequences of peptides isolated from the purified enzyme, and sequenced to be clustered in an operon in the order of A-D-B-C. The operon was found to encode more genes than mdcABCD. The Escherichia coli, transformed with the vector containing the insert mdcADBC and about 1.7 kb of an upstream region, expressed the four subunits of the enzyme but the proteins did not show enzyme activity. It indicates that, like the enzymes from Malonomonas rubra and Klebsiella pneumoniae, more genes are needed for the formation of the functional malonate decarboxylase.     

Mitochondrial regulation in sea urchins. I. Mitochondrial ultrastructure transformations and changes in the ADP:ATP ratio at fertilization.

Mitochondrial ultrastructural transformations have been examined in intact eggs and embryos from three sea urchins, Arbacia punctulata, Strongylocentrotus purpuratus, and Lytechinus pictus. Following fertilization, naturally occurring ultrastructural transformations (designated as condensed to orthodox) were observed to occur in mitochondria of all three families. The ratios of the soluble ADP and ATP pools were examined in eggs of S. purpuratus before and after fertilization in order to test whether the ultrastructural transformations reflect a decrease in relative size of the ADP pool following fertilization. Our data indicate that there is a decrease in the ADP:ATP ratio at fertilization. These findings and their implications are discussed with respect to presently accepted theories on mitochondrial regulation.     

Seasonal acoustic behavior of blue whales (Balaenoptera musculus) in the Gulf of California,Mexico

Six years of passive acoustic monitoring data from the Gulf of California reveal seasonality and movements for the northeastern Pacific blue whales. Three sites were studied, one from the southern (Punta Pescadero) and two from the northern (Isla Tiburon and Canal de Ballenas) regions. A total of 4,953 h were analyzed, and 15,539 blue whale calls were detected, of which 2,723 (18%) were A calls, 11,249 were B calls (72%), and 1,567 were D calls (10%). A and B calls were produced both as song units (2,524) or AB singular calls (2,026). The high rate of songs and their seasonality suggest that the GC is a winter‐breeding ground. A shift from AB call predominance in winter, to D calls in spring and early summer, especially at the entrance of the GC, suggests the importance of this area for reproduction and foraging. Analysis of calling frequency suggests a clear movement of blue whales from the southern region (Punta Pescadero) to the northern regions (Canal de Ballenas and Isla Tiburon), with subsequent southern movement in March. The seasonality and mobility of blue whales in the Gulf of California, inferred from their calling, contributes to the ecological understanding of this population.     

A very diverse amphibian and reptile assemblage from the late Middle Pleistocene of the Sierra de Atapuerca (Sima del Elefante,Burgos, Northwestern Spain)

Among the Pleistocene localities of the Sierra de Atapuerca, the site called Sima del Elefante is famous for having delivered in its lower level (TE-LRU) some hominid remains currently considered the oldest in Western Europe (about 1.2 Ma). In its upper part (TE-URU), this site has fossiliferous levels pertaining to the late Middle Pleistocene (350-250 ka). Here we describe for the first time the amphibians and reptiles of these upper levels (TE18 and TE19), which have proved to be one of the richest assemblages of all the localities of the Sierra de Atapuerca. The faunal list is composed of 18 taxa made up of urodeles (Salamandra salamandra and Lissotriton helveticus), anurans (Discoglossus sp., Alytes sp. Pelobates cultripes, Pelodytes punctatus, Bufo bufo, Bufo calamita, Hyla arborea and cf. Rana sp.), a terrestrial tortoise (Testudo s.l.), lizards (Lacerta s.l., Podarcis sp. and Anguis fragilis) and snakes (Natrix natrix, Natrix maura, Coronella cf. girondica and Vipera latasti). For the first time, the genera Lissotriton, Discoglossus and Podarcis are mentioned in the Pleistocene localities of the Sierra de Atapuerca. TE19 also corresponds to the earliest mention for L. helveticus in the Iberian Peninsula. With the exception of tortoises, all these species are currently present in the province of Burgos, and thus suggests that the herpetofauna has a modern aspect since the Middle Pleistocene. This association of amphibians and reptiles suggests a slightly warmer climate than the current one, but may correspond to a “cold and dry” period if compared with other Pleistocene localities of the Sierra de Atapuerca. The landscape was probably composed of a gallery forest along a quiet water river within a Mediterranean environment alternating laterally between dry meadows, rocky or stony areas and open scrubland.     

Identification of a Novel Gene Signature of ES Cells Self-Renewal Fluctuation through System-Wide Analysis

Embryonic Stem cells (ESCs) can be differentiated into ectoderm, endoderm, and mesoderm derivatives, producing the majority of cell types. In regular culture conditions, ESCs'' self-renewal is maintained through molecules that inhibit spontaneous differentiation enabling long-term cellular expansion. This undifferentiating condition is characterized by multiple metastable states that fluctuate between self-renewal and differentiation balance. Here, we aim to characterize the high-pluripotent ESC metastate marked by the expression of Zscan4 through a supervised machine learning framework based on an ensemble of support vector machine (SVM) classifiers. Our study revealed a leukaemia inhibitor factor (Lif) dependent not-canonical pluripotency signature ({"type":"entrez-nucleotide","attrs":{"text":"AF067063","term_id":"3171143"}}AF067063, {"type":"entrez-nucleotide","attrs":{"text":"BC061212","term_id":"38173992"}}BC061212, Dub1, Eif1a, Gm12794, Gm13871, Gm4340, Gm4850, Tcstv1/3, and Zfp352), that specifically marks Zscan4 ESCs'' fluctuation. This novel ESC metastate is enhanced by high-pluripotency culture conditions obtained through Extracellular signal Regulated-Kinase (ERK) and Glycogen synthase kinase-3 (Gsk-3) signaling inhibition (2i). Significantly, we reported that the conditional ablation of the novel ESC metastate marked by the expression of Gm12794 is required for ESCs self-renewal maintenance. In conclusion, we extend the comprehension of ESCs biology through the identification of a novel molecular signature associated to pluripotency programming.     

Einige nicht-foliicole Arten der FamilieEctolechiaceae (Lichenes) aus Brasilien

Here 13 species of the nonfoliicolous species of the lichen familyEctolechiaceae Zahlbr. em.Haf. are reported, which were found in a collection from Brazil. Six species are described as new:Badimia corticola (sp.n.),Calopadia isidiosa (sp.n.),C. psoromoides (sp.n.),C. subfusca (sp.n.),Tapellaria corticola (sp.n.), andT. schindleri (sp.n.). Seven species have been identified with earlier described species:Calopadia chacoënsis (Malme) comb. n. (=Lopadium chacoënse Malme),C. foliicola (Fée) Vězda,C. fusca (Müll. Arg.) Vězda,C. lecanorella (Nyl.) comb. n.,C. perpallida (Nyl.) Věda,C. phyllogena (Müll. Arg.) Vězda, andTapellaria epiphylla (Müll. Arg.) Sant. A key and illustrations for all studied species are provided, and the nomenclatural problem of the correct generic name of thePyrenotrichum Mont. (anamorph) forCalopadia Vězda orTapellaria Sant. (teleomorphs) are discussed.     

Cooling in the Gulf of St. Lawrence and estuary region at 9.7 to 7.2 C ka (11.2-8.0 cal ka): Palynological response to the PBO and 8.2 cal ka cold events, Laurentide Ice Sheet air-mass circulation and enhanced freshwater runoff

An examination of post-Younger Dryas (YD) pollen stratigraphies in the Gulf of St. Lawrence and St. Lawrence estuary region reveals features in the pollen records that represent breaks in the normal vegetation succession, widespread vegetation suppression, and a delay in migration of plant taxa between 9.7 and 7.2 ¹⁴C ka (11.2 and 8.0 cal ka). The domination of Alnus crispa at sites bordering the St. Lawrence estuary-Gulf region in Gaspésie and northern New Brunswick within this timeframe represents a diversion from the typical vegetation progression from Picea and/or Populus or Picea/Betula to Pinus and/or Betula, and signifies a shift to a cooler, drier climate. Coinciding with the A. crispa expansion and domination in that region was the contraction of Picea populations in other areas. In southwestern New Brunswick and eastern and southeastern Nova Scotia, Picea was replaced by the first appearance of tree birch, B. papyrifera; whereas in western and southwestern Newfoundland, Picea gave way to a resurgence of shrub birch, Betula glandulosa. The Picea contraction and immediate resurgence of Betula represents cooling, and is reliably dated at 9720 ± 110 ¹⁴C BP (10,800-11,240 cal BP) in southwest Newfoundland. This first post-YD episode of widespread cooling is correlated with the North Atlantic Preboreal Oscillation (PBO) centered around 9650 ¹⁴C BP (10,900-11,180 cal BP) in the adjacent Great Lakes region. Sites exposed to winds from the Gulf of St. Lawrence in eastern New Brunswick, Prince Edward Island, and northern Nova Scotia show a lingering persistence of Picea and delay in arrival of Pinus to 8.0 and 7.7 ¹⁴C ka (9.0 and 8.4 cal ka), yet Pinus was dominant as early as 9.4 ¹⁴C ka (10.6 cal ka) in southwestern New Brunswick. At the same time, tundra vegetation persisted at high elevations in western and southwestern Newfoundland only to be replaced by upslope migration of shrub-birch heath by 8 ¹⁴C ka. Prolonged broad-scale cooling to 8 ¹⁴C ka and to as late as 7.7 ¹⁴C ka extended up to 200 km inland in areas exposed to the St. Lawrence estuary and Gulf region and was in response to strong, cold, dry anticyclonic winds coming off the retreating Laurentide Ice Sheet in combination with enhanced freshwater runoff through the Gulf of St. Lawrence.The end of the period of prolonged cooling and onset of regional warming coincided with the diversion of western Canada runoff and Agassiz-Ojibway drainage to Hudson Bay and reduced effect or final break-up of the Laurentide Ice Sheet. Several sites document a subsequent cold shift, that interrupted regional warming at 7650 to 7200 ¹⁴C BP (8400 to 8000 cal BP), and which is variously represented by the suppression of Pinus and resurgence of Picea, sometimes with A. crispa (Québec-Maritime region), or by an abrupt decrease of Picea and resurgence of Betula (western Newfoundland). This second post-YD cool interval is equated with the 8200 cal BP cold event registered in the Greenland ice isotopic record.     

New weevils (Curculionidae) in Baltic amber

The new subtribes Palaeorhamphina subtrib. nov. of the tribe Rhamphini and Eocenesibiniina subtrib. nov. of the tribe Tychiini, new genera Archaeoeugnomus gen. nov. (type species A. balticus sp. nov.), Palaeorhamphus gen. nov. (type species P. primitivus sp. nov.), and Eocenesibinia gen. nov. (type species E. prussica sp. nov.), new subgenus Palaeoleiosoma subgen. nov. (type species L. klebsi sp. nov.) of the genus Leiosoma Stephens, and new species Leiosoma klebsi sp. nov., Caulophilus rarus sp. nov., C. squamosus sp. nov., Ceutorhynchus alekseevi sp. nov., C. electrinus sp. nov., Dorytomus nudus sp. nov., Pachytychius eocenicus sp. nov., Archaeoeugnomus balticus sp. nov., Palaeorhamphus primitivus sp. nov., Orchestes tatjanae sp. nov., and Eocenesibinia prussica sp. nov. are described. Electrotribus Hustache, 1942 placem. nov. is transferred from the tribe Derelomini of the subfamily Curculioninae to the tribe Acicnemidini of the subfamily Molytinae. Succinostyphlus erectosquamata (Rheinheimer, 2007) placem. nov. et comb. nov. is transferred from the genus Electrotribus Hustache, 1942 to the genus Succinostyphlus Ku?ka, 1996. These are the first records of representatives of the tribes Plinthini, Acicnemidini, Eugnomini, and Rhamphini in the Baltic amber.