Population genetics information for the regional conservation of a tropical seagrass, <Emphasis Type="Italic">Enhalus acoroides</Emphasis>, around the Guimaras Strait,Philippines

Seagrasses are marine angiosperms and play an essential ecological role in coastal ecosystems; however, seagrass meadows are threatened locally by anthropogenic disturbances. Understanding the dispersal patterns of seagrasses is essential for appropriate ecosystem management and establishment of marine protected areas (MPAs) in coastal ecosystems. In the Guimaras Strait in the Philippines, Banate (BAN) has been established as an MPA. However, there is a lack of information on the genetic diversity of seagrasses in BAN and the surrounding areas. In the present study, population genetics analysis of Enhalus acoroides was performed by using polymorphic microsatellite markers, for the estimation of genetic diversity, differentiation, and migration patterns of seagrasses within the regional geographical scale (~200 km) around the Guimaras Strait. The results showed that the genetic diversity of BAN is extremely low, although the Guimaras Strait is located in the tropical central habitat. Guimaras Island geographically divides the populations of E. acoroides into south and north. However, the genetic structure did not show any relationship between the geographical location and distance. The floating, buoyant fruits of E. acoroides may play a role in their long-distance dispersal; however, such dispersal is not frequent. Almost all of the seeds and fruits are derived from self-recruitment in the natal meadow. This study suggests that E. acoroides populations possess a weak genetic connectivity, and that the persistence of the meadow is threatened due to the low genetic diversity and high degree of population isolation in BAN. To maintain and enhance the genetic diversity of seagrasses within the MPA, the seagrass meadows in the surrounding areas should also be conserved.     

The species of Aspidorhynchus Agassiz, 1833 (Neopterygii,Aspidorhynchiformes) from the Jurassic plattenkalks of Southern Germany

The fishes of the genus Aspidorhynchus (Aspidorhynchidae) are among the most abundant predators in the palaeolagoons of the Solnhofen archipelago (Late Jurassic, southern Germany). They have been known since the end to the nineteenth century and the last revision of the genus was published more than 20 years ago. During these last two decades, numerous complete and excellently preserved specimens have been collected. The high morphological diversity shown by the new material made a new revision of these fishes necessary. This new taxonomic revision led us to revalidate the species A. ornatissimus Agassiz, 1834, which has hitherto been considered a junior synonym of the type species of the genus, A. acutirostris (Blainville, 1818), as well as to recognize high intraspecific variation in the latter species. These results helped to improve the distinction and, thus, the diagnoses of A. acutirostris, A. ornatissimus, and A. sanzenbacheri Brito and Ebert, 2009, which are the three valid species of this genus in the Solnhofen archipelago. We have been able to explain most of the intraspecific diversity of A. acutirostris by means of patterns of ontogenetic variation that encompass most of the other nominal species, thus largely reflecting early taxonomic hypotheses. Furthermore, the detailed morphological study led us to the recognition of some important anatomical structures previously unknown for aspidorhynchids: a connection between the temporal, infraorbital and supraorbital sensory canals in the frontal bone, the presence of an Y-shaped antorbital bone, and the presence of an interoperculum.     

Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test

The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4⁺ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 10⁶ IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 10⁶ SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.     

A Complex Population Structure of the Cassava Pathogen Xanthomonas axonopodis pv. manihotis in Recent Years in the Caribbean Region of Colombia

Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis (Xam), is the most important bacterial disease affecting this crop. A continuous surveillance of the pathogen population dynamics is required to develop an efficient disease management program. During the 1990s, Xam populations showed high levels of genetic variation and relevant migratory processes that were important determinants of the distribution of the pathogen diversity in Colombia. Aiming to characterize the current population structure of the pathogen and the evolutionary forces that shape these populations, sampling collections were carried out from September 2008 until November 2010 in the Colombian Caribbean Region. One hundred and sixty bacterial isolates were characterized using amplified fragment length polymorphism (AFLP) markers. Additionally, a subset of effector genes were sequenced in some isolates to determine their usefulness in Xam population studies and to provide additional information to that obtained with AFLPs. Virulence patterns of ten isolates were determined in nine cassava accessions. Our results show a complex architecture of population and confirm migratory process previously reported in the Caribbean Region. Chinú, one of the locations sampled, presented remarkable features in population dynamics such as longer genetic distances, higher diversity indices, and a genetically differentiated population when it was compared with other locations. Virulence tests showed that MCOL2215, one of the most cultivated cassava varieties in the Caribbean coast, was susceptible to the majority of Xam isolates tested. This study shows the current condition of populations of Xam in the Caribbean Region of Colombia, and it contributes to improve the existing bacterial blight control practices.     

The claw closer muscle of Neohelice granulata (Grapsoidea,Varunidae): a morphological and histochemical study

Longo, M.V., Goldemberg, A.L. and Díaz, A.O. 2011. The claw closer muscle of Neohelice granulata (Grapsoidea, Varunidae): a morphological and histochemical study. —Acta Zoologica (Stockholm) 92 : 126–133. The claw closer muscle of Neohelice granulata was studied according to histological, histochemical, and morphometrical criteria. Adult male crabs in intermoult stage were collected from Mar Chiquita Lagoon (Buenos Aires, Argentina). Muscle fibers show evident striations and oval‐elongated nuclei with loose chromatin. The loose connective tissue among muscle fibers consists of cells and fibers embedded in an amorphous substance. Muscle histochemistry reveals two slow fiber types: ‘A’ and ‘B’. Prevailing A fibers are larger, and they usually show, with respect to B type, a weaker reaction to whole techniques. Fibers with short (SS), intermediate (IS), and long sarcomeres (LS) appear in the claw closer muscle, being the LS fibers predominant. Concluding, the histochemical and morphometrical characteristics of the claw closer muscle fibers of N. granulata are indicative of slow fibers. The slow A type (low resistant to fatigue) prevails.     

<Emphasis Type="Italic">Saturnispora serradocipensis</Emphasis> sp. nov. and <Emphasis Type="Italic">Saturnispora gosingensis</Emphasis> sp. nov., two ascomycetous yeasts from ephemeral habitats

Two novel ascomycetous yeast species, Saturnispora serradocipensis and Saturnispora gosingensis, were isolated from leaf detritus in a tropical stream of Southeastern Brazil and a mushroom collected in Taiwan, respectively. Analysis of the D1/D2 domains of the large-subunit of the rRNA gene of these strains showed that these species are related to Saturnispora hagleri, their closest relative. Saturnispora serradocipensis and S. gosingensis differed from S. hagleri, respectively, by seven nucleotide substitutions and two indels and three nucleotide substitutions and three indels in D1/D2 rRNA sequences. The two new species differ from each another by four nucleotide substitutions and one indel in D1/D2 rRNA sequences. However, the ITS sequences of S. serradocipensis, S. gosingensis and S. hagleri were quite divergent, showing that they are genetically separate species. The type strain of S. serradocipensis is UFMG-DC-198^T (=CBS 11756^T = NRRL Y-48717^T), and of S. gosingensis GA4M05^T is (CBS 11755^T = NRRL Y-48718^T).