32 research outputs found
Effect of cholesterol on the interaction of the amphibian antimicrobial peptide DD K with liposomes.
The Oldest Case of Decapitation in the New World (Lapa do Santo, East-Central Brazil)
We present here evidence for an early Holocene case of decapitation in the New World (Burial 26), found in the rock shelter of Lapa do Santo in 2007. Lapa do Santo is an archaeological site located in the Lagoa Santa karst in east-central Brazil with evidence of human occupation dating as far back as 11.7-12.7 cal kyBP (95.4% interval). An ultra-filtered AMS age determination on a fragment of the sphenoid provided an age range of 9.1-9.4 cal kyBP (95.4% interval) for Burial 26. The interment was composed of an articulated cranium, mandible and first six cervical vertebrae. Cut marks with a v-shaped profile were observed in the mandible and sixth cervical vertebra. The right hand was amputated and laid over the left side of the face with distal phalanges pointing to the chin and the left hand was amputated and laid over the right side of the face with distal phalanges pointing to the forehead. Strontium analysis comparing Burial 26's isotopic signature to other specimens from Lapa do Santo suggests this was a local member of the group. Therefore, we suggest a ritualized decapitation instead of trophy-taking, testifying for the sophistication of mortuary rituals among hunter-gatherers in the Americas during the early Archaic period. In the apparent absence of wealth goods or elaborated architecture, Lapa do Santo's inhabitants seemed to use the human body to express their cosmological principles regarding death
Synthesis of photosynthesis-inhibiting nostoclide analogues
A series of thirty four 3-benzyl-5-(arylmethylene)furan-2(5H)-ones, designed using the naturally-occurring toxins nostoclides as a lead structure, wassynthesized as potential inhibitors of the photosynthetic electron transport. All compounds were fully characterized by IR, NMR (1H and 13C) and MS spectrometry. HMBC and HSQC bidimensional experiments allowed 13C and 1H assignments. Their biological activities were evaluated in vitro as the ability to interfere with light-driven reduction of ferricyanide by isolated spinach chloroplasts. About two-thirds of the compounds exhibited inhibitory properties in the micromolar range against the basal electron flow from water to K3[Fe(CN)6]. The inhibitory potential of these 3-benzyl-5-(arylmethylene)furan-2(5H)-one lactones is higher than that of other nostoclide analogues previously synthesized in our laboratories
Are tidal lagoons ecologically relevant to larval recruitment of small pelagic fish : an approach using nutritional condition and growth rate
There are numerous studies dealing with larvae of Small Pelagic Fish (SPF), but only a few have actually
addressed advanced larval phases. Temperate coastal lagoons are particularly understudied, due to the
absence of standard method to capture advanced larval fish in these near shore shallow habitats.
Accordingly, this study aims to describe abundances, nutritional condition and in situ growth of postflexion
(SPF) from the Ria Formosa, a tidal coastal lagoon in southern Portugal. The nutritional condition
and in situ growth were determined through cohort analysis and standardized RNA:DNA ratio (sRD),
complemented with feeding incidence (gut content) and fatty acids (FAs, trophic biomarkers) of postflexion
larvae sampled sequentially with light traps, from spring 2005 to summer 2006. Simultaneously,
environmental parameters such as water temperature, salinity, dissolved oxygen and chlorophyll a were
measured. Post-larvae of SPF were captured through the year in important numbers. The dominant
species were Sardina pilchardus (50.7%), Engraulis encrasicolus and Atherina presbyter (11.4%). These
results are distinct from those based on adult/juvenile surveys or early planktonic phases in the Ria
Formosa where clupeiformes were occasionally reported. Sardines were captured mainly in winter,
spring and early summer and anchovies mainly during summer and autumn. Sand smelt, a resident
species, was present throughout the year. In the early summer, the three species were present and during
this period some diet overlapping occurred, the feeding incidence of the clupeiformes was very low, but
atherinids always exhibited full guts reflecting the different gut morphology or indicating different lifecycle
strategies. The bulk of the diet was mollusks, crustaceans and appendicularians, for sand smelts,
sardines and anchovies, respectively. The results of FA analyses showed some contribution of phytoplankton
to SPF in the area. All SPF exhibited higher condition (sRD) and growth rates in summer, which
are explained by the adequate temperature and higher planktonic productivity. This is especially relevant
because the successful development of postflexion larvae in these nursery areas largely determines the
successful recruitment to adult fish populations.info:eu-repo/semantics/publishedVersio
Temporal variability of biodiversity patterns and trophic structure of estuarine macrobenthic assemblages along a gradient of metal contamination
The present study aimed to investigate the response of macrobenthic assemblages along a gradient of
metal contamination using a combination of uni- and multivariate methods focusing on their composition,
structure and function. A total of six sites were established based on a preliminary survey, which
identified three areas with different levels of contamination. These areas were defined as slightly
contaminated (SC), moderately contaminated (MC) and highly contaminated (HC). Each area comprised
two sites, sampled in four sampling surveys (September 2012, February, May and October of 2013). To
investigate the response of the macrobenthic assemblages the number of individuals (N), number of taxa
(S), ShannoneWeaver diversity (H0), Pielou's equitability (J0) and different distance-based multivariate
measures of b-diversity (complementarity) were analysed. b-diversity as turnover was also analysed
together with spatial and temporal changes in the trophic structure. A clear gradient of increasing
contamination was consistently detected, but comparisons with available sediment quality guidelines
indicated that adverse biological effects may be expected in all areas. This result suggests measuring
concentrations of contaminants in the sediment per se may be insufficient to establish a clear link between
ecological patterns and the contamination of the system. Also it highlights the difficulty of
identifying reference areas in highly urbanized and industrialized estuaries. Only multivariate analysis
(dbRDA; both using the taxonomic and trophic composition) and b-diversity as turnover showed a
consistent response to metal contamination. Higher heterogeneity, mainly due to contribution of rare
species (i.e. species present in a single sampling period), was observed in the least contaminated area
(SC), decreasing towards the HC. In terms of the trophic function, a shift from a dominance of carnivores
in the SC to the dominance of deposit-feeding organisms (and associations) along the contamination
gradient was evident