A major difference between the divergence patterns within the lines-1 families in mice and voles

L1 retroposons are represented in mice by subfamilies of interspersed sequences of varied abundance. Previous analyses have indicated that subfamilies are generated by duplicative transposition of a small number of members of the L1 family, the progeny of which then become a major component of the murine L1 population, and are not due to any active processes generating homology within preexisting groups of elements in a particular species. In mice, more than a third of the L1 elements belong to a clade that became active approximately 5 Mya and whose elements are > or = 95% identical. We have collected sequence information from 13 L1 elements isolated from two species of voles (Rodentia: Microtinae: Microtus and Arvicola) and have found that divergence within the vole L1 population is quite different from that in mice, in that there is no abundant subfamily of homologous elements. Individual L1 elements from voles are very divergent from one another and belong to a clade that began a period of elevated duplicative transposition approximately 13 Mya. Sequence analyses of portions of these divergent L1 elements (approximately 250 bp each) gave no evidence for concerted evolution having acted on the vole L1 elements since the split of the two vole lineages approximately 3.5 Mya; that is, the observed interspecific divergence (6.7%-24.7%) is not larger than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses showed no clustering into Arvicola and Microtus clades.      

Multifactorial diversity sustains microbial community stability

Maintenance of a high degree of biodiversity in homogeneous environments is poorly understood. A complex cheese starter culture with a long history of use was characterized as a model system to study simple microbial communities. Eight distinct genetic lineages were identified, encompassing two species: Lactococcus lactis and Leuconostoc mesenteroides. The genetic lineages were found to be collections of strains with variable plasmid content and phage sensitivities. Kill-the-winner hypothesis explaining the suppression of the fittest strains by density-dependent phage predation was operational at the strain level. This prevents the eradication of entire genetic lineages from the community during propagation regimes (back-slopping), stabilizing the genetic heterogeneity in the starter culture against environmental uncertainty.     

Begomoviruses Infecting Tomato Crops in Panama

The key regions in Panama involved in open field‐ and greenhouse‐grown commercial tomato production, including the Chiriquí, Veraguas, Herrera, Los Santos, Coclé and Panama Oeste provinces, were surveyed for the incidence and distribution of begomoviruses in the growing seasons of 2011 and 2012. The surveys took place in 14 of the 51 districts of the above‐mentioned provinces and comprised all relevant tomato production areas of the provinces. A total of 28 tomato plots were surveyed. The exact location of each plot was geo‐referenced using a hand‐held Global Positioning System unit. In total, 319 individual tomato plants (181 in 2011 and 138 in 2012) were sampled. Plants displayed diverse combinations of virus‐like symptoms of different severity, including necrosis, yellowing, mosaic, mottling, rolling, curling, distortion and puckering of leaves, reduced leaf size, and stunted growth. DNA was extracted from each plant for a subsequent polymerase chain reaction (PCR) analysis, using two sets of degenerate primers able to detect members of the genus Begomovirus. The samples displaying a positive reaction were subsequently analysed with specific primer pairs to identify the affecting begomoviruses. A total of 42.3% of all collected samples showed a positive signal to PCRs. Three begomovirus species were detected with the species‐specific set of primers; in particular, in the samples obtained in 2011, Potato yellow mosaic Panama virus (PYMPV), Tomato leaf curl Sinaloa virus (ToLCSiV) and Tomato yellow mottle virus (TYMoV) were detected, while in the 2012 samples, only PYMPV and ToLCSiV were found. To our knowledge, this is the first reported incidence of ToLCSiV and TYMoV in Panamanian tomato crops.     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.     

Rapid detection and discrimination of fabaviruses by flow‐through hybridisation with genus‐ and species‐specific riboprobes

Viruses cause significant damage in agricultural crops worldwide. Disease management requires sensitive and specific tools for virus detection and identification. Also, detection techniques need to be rapid to keep pace with the continuous emergence of new viral diseases. The genus Fabavirus is composed of five viruses infecting many economically important crops worldwide. This research describes the development of a procedure based on flow‐through hybridisation (FTH), which is faster than and as sensitive as conventional hybridisation for virus detection in tissue‐prints from infected plants. Six digoxigenin‐labelled RNA probes were synthesised with two levels of specificity: (a) five specific for each viral species within this genus, and (b) a genus‐specific probe that hybridises with a nucleotide sequence signature only found in the 5′‐untranslated region of the genus Fabavirus, which is the first of this type reported for plant viruses. The new procedure developed is useful for rapid detection and discrimination of the five fabaviruses identified so far and opens the possibility of discovering new species of this genus.     

Estuarine fouling communities are dominated by nonindigenous species in the presence of an invasive crab

Interactions between anthropogenic disturbances and introduced and native species can shift ecological communities, potentially leading to the successful establishment of additional invaders. Since its discovery in New Jersey in 1988, the Asian shore crab (Hemigrapsus sanguineus) has continued to expand its range, invading estuarine and coastal habitats in eastern North America. In estuarine environments, H. sanguineus occupies similar habitats to native, panopeid mud crabs. These crabs, and a variety of fouling organisms (both NIS and native), often inhabit man-made substrates (like piers and riprap) and anthropogenic debris. In a series of in situ experiments at a closed dock in southwestern Long Island (New York, USA), we documented the impacts of these native and introduced crabs on hard-substrate fouling communities. We found that while the presence of native mud crabs did not significantly influence the succession of fouling communities compared to caged and uncaged controls, the presence of introduced H. sanguineus reduced the biomass of native tunicates (particularly Molgula manhattensis), relative to caged controls. Moreover, the presence of H. sanguineus favored fouling communities dominated by introduced tunicates (especially Botrylloides violaceous and Diplosoma listerianum). Altogether, our results suggest that H. sanguineus could help facilitate introduced fouling tunicates in the region, particularly in locations where additional solid substrates have created novel habitats.