Differential DNA methylation and gene expression during development of reproductive and vegetative organs in Ilex species

Journal of Plant Research - Differential epigenetic (DNA cytosine methylation) and gene expression patterns were investigated in reproductive and vegetative organs from Ilex paraguariensis and I....     

Human choriogonadotropin-like material in bacteria of different species: electron microscopy and immunocytochemical studies with monoclonal and polyclonal antibodies

Immunocytochemical studies using antisera to whole human choriogonadotropin (hCG), to its alpha- and beta-subunits and to the COOH-terminal peptide of hCG beta, and two monoclonal antibodies to hCG beta, demonstrated expression of hCG-like material, its individual subunits and/or fragments in nine bacterial strains. Seven of these were isolated from patients with cancer and were definitely identified as Streptococcus faecalis (three strains), Staphylococcus haemolyticus (two strains) and Staphylococcus epidermidis and Escherichia coli (single strains). The other two strains were cell-wall-deficient (CWD) variants, one identified as Streptococcus bovis, isolated from the blood of a patient with a fever of unknown origin and a possible brain abscess. The other was a Gram-negative diphtheroid isolated from the urine of a pregnant woman, which during the period of study reverted to a Gram-positive Corynebacterium identified as a 'C. ulcerans' strain and expressed the hCG-like factor only during its phase as Gram-negative diphtheroid. Electron microscopy of these nine strains (including negative controls of strains of the same species subjected to the same immunocytochemical analyses and under identical cultural conditions) revealed morphological alterations in the bacterial cell walls and cytoplasmic material and/or bizarre forms of reproduction in six of the nine strains expressing hCG-like material including the two CWD variants. Collectively, these results provided evidence that (1) hCG-producing bacteria isolated from patients with overt cancer are not a new and unique species as claimed by others, and (2) there is a close resemblance between the bacterial protein and the human trophoblastic hormone, based on immunochemical recognition of different parts of the hCG molecule.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inferring nocturnal surface fluxes from vertical profiles of scalars in an Amazon pasture

Ecosystem carbon budgets depend on there being good representative surface flux observations for all land use types during the entire diurnal cycle. In calm conditions that often occur at night, especially in areas of small roughness (such as pastures), ecosystem respiration rate is poorly measured using the eddy covariance (EC) technique. Nocturnal vertical profiles of temperature, humidity and winds were observed using tethered balloon soundings in a pasture in the eastern Amazon during two campaigns in 2001. The site is characterized by very weak winds at night, so that there is insufficient turbulence for the EC technique to determine fluxes accurately. To compensate, the time evolution of the profiles is used to determine surface fluxes at early morning and these are compared with those observed by EC at a nearby micrometeorological tower. The nocturnal boundary layer thickness h is determined as the height to which the surface fluxes must converge so that energy budget closure is achieved. The estimated values range from 30 m, around 22:00 hours LST, to more than 100 m just before dawn. These are in good agreement with the observed thickness of a frequently observed fog layer during the middle of the night. During the early portion of the night, when the accumulation layer is shallow, there is appreciable decrease of dCO₂/dt with height. On calm nights, CO₂ accumulation rate is larger near the surface than at higher levels. On windier nights, this accumulation rate is vertically uniform. Hence, extrapolation of tower profiles for estimating fluxes must be done carefully. Although uncertainties remain large, an alternate approach to the EC method is described for measuring nighttime surface CO₂ fluxes under stable atmospheric conditions.     

Vagrant Subantarctic fur seal at Cape Shirreff,Livingston Island,Antarctica

A vagrant adult male Subantarctic fur seal Arctocephalus tropicalis was observed among Antarctic fur seals A. gazella at Cape Shirreff, Livingston Island, Antarctica, which is located to ~4,190 and ~5,939 km from the nearest breeding colonies of Subantarctic fur seals. Although the colony of origin of this animal and the reason for its movement outside its distribution range are unknown, this sighting shows the high dispersal capacity of this species and provides an insight into possible changes in its distribution. Although this vagrant was not observed with females Antarctic fur seal, news sightings in the future could result in viable hybrid, and introgressive hybridization could represent a threat for Cape Shirreff population recovery, if still the population way to go to recover to presailing levels.     

Offspring kidnapping with subsequent shared nursing in Antarctic fur seals

Non-offspring maternal care should be common in phocids, but their occurrence would be uncommon among otariids due to the high costs of raising offspring, particularly lactation, and an efficient recognition system that allow for accurate recognition during the frequent mother–pup re-associations. However, non-offspring maternal care has been documented in some otariid species. While the phenomenon in general is not novel among the colonially breeding seals, the exclusive care to a single pup by two lactating females for an extended time is a behavior scarcely documented in natural population. In an extension of this allonursing care, we document the first case of the kidnapping of a pup with subsequent shared nursing in Antarctic fur seal including data on the effect of this interaction on the pup’s growth. While all other lactating females nursed exclusively their own pups, the shared nursing was advantageous for the pup because he grew noticeably larger (in weight and axillary girth) than other of his cohort, particularly after 50 days. This advantage would have been influenced by the asynchrony of the foraging cycle of the biological and foster mother, which resulted in a higher attendance on shore than any other male pups. Although several explanations have been hypothesized for allolactation in mammals, our observations suggest a misguided parental care, associated with recognition errors by the foster mother whose pup was stillborn.     

Isolation and characterisation of polymorphic microsatellite markers for the endangered ferreous limpet <Emphasis Type="Italic">Patella ferruginea</Emphasis> (Gastropoda,Patellidae)

The limpet Patella ferruginea is one of the most endangered marine invertebrates on western Mediterranean rocky shores. We have isolated and characterised 11 polymorphic microsatellites markers to provide new tools to investigate genetic structure and gather information necessary for the proper management of this severely threatened species. The number of alleles per locus ranged from 2 to 16 (mean; Na = 8.37) with an average observed heterozygosity of 0.64 (He = 0.66). The levels of polymorphism uncovered at these loci suggest that they should be useful for population genetic studies, parentage analysis and assessment of connectivity among protected areas. None of the pairwaise comparisons among loci showed significant linkage disequilibrium after sequential Bonferroni correction. All but one locus (Pf-31IF1) conformed to HW equilibrium. Further investigation revealed that departures at Pf-31IF1 were not caused by null alleles. Results from cross-species amplifications suggest that some of these loci may also be useful for Patella tenuis (two loci) P. ulyssiponensis (one locus) and P. piperata (three loci).