Factors determining tadpole vulnerability to predators: can prior experience compensate for a suboptimal shape?

We investigated the role of constitutive morphology and previous experience in predator avoidance in two anuran species associated with different larval habitats. In Rana temporaria, deeper tails and larger body size conferred selective advantage against dragonfly predation. Previous experience with predators had a positive influence on the survival of R. temporaria tadpoles equivalent to predator selection. By contrast, survival in Bufo bufo seems unrelated to tail shape or experience. This suggests that B. bufo lacks constitutive morphological defenses against insect predators, and that morphological and behavioral defenses could result more effective than chemical deterrents for these insect predators. A key novelty of this study is the observation that Rana tadpoles having prior experience with predators have an enhanced success in further encounters, and this occurs before the morphological induced defense has been established. This induced modification for R. temporaria, and its lack of for B. bufo, may be an important determinant of larval survival.     

DNA damage in mouse lymphocytes exposed to curcumin and copper

Dietary polyphenolics, such as curcumin, have shown antioxidant and anti-inflammatory effects. Some antioxidants cause DNA strand breaks in excess of transition metal ions, such as copper. The aim of this study was to evaluate thein vitro effect of curcumin in the presence of increasing concentrations of copper to induce DNA damage in murine leukocytes by the comet assay. Balb-C mouse lymphocytes were exposed to 50 μM curcumin and various concentrations of copper (10 μM, 100 μM and 200 μM). Cellular DNA damage was detected by means of the alkaline comet assay. Our results show that 50 μM curcumin in the presence of 100–200 μM copper induced DNA damage in murine lymphocytes. Curcumin did not inhibit the oxidative DNA damage caused by 50 μM H₂O₂ in mouse lymphocytes. Moreover, 50 μM curcumin alone was capable of inducing DNA strand breaks under the tested conditions. The increased DNA damage by 50 μM curcumin was observed in the presence of various concentrations of copper, as detected by the alkaline comet assay.     

Amino terminal sequence of heavy and light chains from ratfish immunoglobulin

The ratfish,Callorhinchus callorhinchus, a representative of the Holocephali, has a natural serum hemagglutinin (M _r 960 000), composed of heavy (M _r 71000), light (M _r 22 500), and J (M _r 16 000) chains. To approach the mechanisms that generate diversity at this level of evolution, the amino terminal sequence of the heavy and light chains was determined by automated microsequencing. The chains are unblocked and have modest internal sequence heterogeneity. The heavy chains show sequence similarity with the terminal region of the heavy chain from the horned shark,Heterodontus francisci, and other species. In contrast to the heavy chain, the ratfish light chains display low sequence similarity with their shark kappa counterparts. However, their similarity with the variable region of the chicken lambda light chains is about 75%.     

Establishment and Biological Characterization of a Panel of Glioblastoma Multiforme (GBM) and GBM Variant Oncosphere Cell Lines

Objective

Human tumor cell lines form the basis of the majority of present day laboratory cancer research. These models are vital to studying the molecular biology of tumors and preclinical testing of new therapies. When compared to traditional adherent cell lines, suspension cell lines recapitulate the genetic profiles and histologic features of glioblastoma multiforme (GBM) with higher fidelity. Using a modified neural stem cell culture technique, here we report the characterization of GBM cell lines including GBM variants.

Methods

Tumor tissue samples were obtained intra-operatively and cultured in neural stem cell conditions containing growth factors. Tumor lines were characterized in vitro using differentiation assays followed by immunostaining for lineage-specific markers. In vivo tumor formation was assayed by orthotopic injection in nude mice. Genetic uniqueness was confirmed via short tandem repeat (STR) DNA profiling.

Results

Thirteen oncosphere lines derived from GBM and GBM variants, including a GBM with PNET features and a GBM with oligodendroglioma component, were established. All unique lines showed distinct genetic profiles by STR profiling. The lines assayed demonstrated a range of in vitro growth rates. Multipotency was confirmed using in vitro differentiation. Tumor formation demonstrated histologic features consistent with high grade gliomas, including invasion, necrosis, abnormal vascularization, and high mitotic rate. Xenografts derived from the GBM variants maintained histopathological features of the primary tumors.

Conclusions

We have generated and characterized GBM suspension lines derived from patients with GBMs and GBM variants. These oncosphere cell lines will expand the resources available for preclinical study.     

Phylogeny and morphology of the <Emphasis Type="Italic">Peziza ammophila</Emphasis> complex (Pezizales,Ascomycota), with description of two new species and a new form

This study was focused on species of Peziza belonging to the “P. ammophila” complex, using both morphological and molecular approaches. Molecular and morphological analyses showed that several taxa are hidden under the name “ammophila” and, as a consequence, two additional species and one form are established: P. hellenica sp. nov., P. oceanica sp. nov. and P. ammophila f. megaspora f. nov. On the basis of the data that we have, these taxa seem to be related to some geographical areas; P. ammophila appears to be prevalent in northern, central and southern Europe, its f. megaspora is distributed in France and in the Netherlands, P. hellenica comes from Greece and P. oceanica from New Zealand. A cryptic species, not yet circumscribed satisfactorily, is described as P. deceptiva ad int. Moreover, the problem concerning the identification of P. ammophila is raised, the species is epitypified with a sequenced collection from Sicily (Italy) and a key to the species of the complex is provided.     

Variation in parental rearing expenditure triggers short‐term physiological effects on offspring in a long‐lived seabird

Parental care in long‐lived bird species involves a trade‐off between the benefits of increasing the effort expended on current offspring and the costs that this represents for future reproductive output. Under regimes of high environmental variability, long‐lived seabirds can adjust their breeding effort to buffer the negative effects of this variability on their offspring. However, the potential impacts of variation in breeding effort on offspring physiology in the short term and on longer‐term survival are poorly understood. In this study, we manipulated brood age through a cross‐fostering experiment to assess whether increasing or decreasing parental reproductive expenditure led to costs in Blue‐footed Booby Sula nebouxii chicks. Specifically, we tested the consequences of altered parental reproductive expenditure on the offspring's physiological condition (plasma metabolites, heterophil to lymphocyte ratio (H/L) and body condition index (BCI)) and survival. Offspring from broods in which parental investment was experimentally increased showed a lower BCI and lower alkaline phosphatase levels and higher H/L ratios than controls. Conversely, offspring showed the opposite pattern when reproductive expenditure was experimentally decreased. We observed no effects of manipulation of parental investment on triglyceride levels or on survival rates. Although our findings suggest that Blue‐footed Booby parents have the ability to adjust their breeding effort according to the demands of their offspring, parental effort could influence the effect of hatching order by suppressing the aggressive tendency of the senior chick.     

A dual fluorescent/MALDI chip platform for analyzing enzymatic activity and for protein profiling

Being able to rapidly and sensitively detect specific enzymatic products is important when screening biological samples for enzymatic activity. We present a simple method for assaying protease activity in the presence of protease inhibitors (PIs) by measuring tryptic peptide accumulation on copolymer pMALDI target chips using a dual fluorescence/MALDI‐TOF‐MS read‐out. The small platform of the chip accommodates microliter amounts of sample and allows for rapid protein digestion. Fluorescamine labeling of tryptic peptides is used to indicate the proteolytic activity and is shown to be an affordable, simple process, yielding a strong fluorescence signal with a low background. Subsequent MALDI‐TOF‐MS analysis, performed in the same sample well, or in a parallel well without adding fluorescamine, detects the specific tryptic peptides and provides confidence in the assay. The dual read‐out method was applied to screen the inhibition activity of plant PIs, components of plant defense against herbivores and pathogens. Extracts of PIs from Solanum nigrum and trypsin were applied together to a pMALDI chip on which a suitable substrate was adsorbed. The fluorescence and MALDI‐TOF‐MS signal decrease were associated with the inhibitory effect of the PIs on trypsin. The developed platform can be modified to screen novel protease inhibitors, namely, those potentially useful for treating or preventing infection by viruses, including HIV and hepatitis C.     

Origins of domestication and polyploidy in oca (Oxalis tuberosa; Oxalidaceae). 3. AFLP data of oca and four wild, tuber-bearing taxa

Many crops are polyploids, and it can be challenging to untangle the often complicated history of their origins of domestication and origins of polyploidy. To complement other studies of the origins of polyploidy of the octoploid tuber crop oca (Oxalis tuberosa) that used DNA sequence data and phylogenetic methods, we here compared AFLP data for oca with four wild, tuber-bearing Oxalis taxa found in different regions of the central Andes. Results confirmed the divergence of two use-categories of cultivated oca that indigenous farmers use for different purposes, suggesting the possibility that they might have had separate origins of domestication. Despite previous results with nuclear-encoded, chloroplast-expressed glutamine synthetase suggesting that O. picchensis might be a progenitor of oca, AFLP data of this species, as well as different populations of wild, tuber-bearing Oxalis found in Lima Department, Peru, were relatively divergent from O. tuberosa. Results from all analytical methods suggested that the unnamed wild, tuber-bearing Oxalis found in Bolivia and O. chicligastensis in NW Argentina are the best candidates as the genome donors for polyploid O. tuberosa, but the results were somewhat equivocal about which of these two taxa is the more strongly supported as oca's progenitor.     

Variation in digestive performance between geographically disjunct populations of Atlantic salmon: countergradient in passage time and digestion rate

European Atlantic salmon (Salmo salar) populations inhabit rivers from northern Portugal to northern Norway across a wide spectrum of environmental variability. To address whether single physical factors might lead to genetic divergence of isolated populations, we compared the digestive performances total digestibility, relative nitrogen digestibility, passage time, and digestion rate (g dry matter · h^–1) — of northern (Scotland) and southern (Asturias, northern Spain) populations at three temperature regimes (5, 12, and 20° C). Total dry matter digestibilities increased directly with temperature but were similar for both populations at each of the three trials. Relative nitrogen digestibility did not differ between populations nor among temperature regimes. In contrast, passage time was significantly longer for low-than for high-latitude fish at both 5 and 20° C. When the percentage of food digested and the passage time were integrated as digestion rates (food digested per unit time), a significant population × temperature interaction consistent with a genotype × environment interaction was detected in addition to the population and temperature effects. This implies that not only is the digestive performance of the high-latitude population higher throughout the range of temperatures examined, but moreover the difference is reinforced at high temperatures, where the digestion rate of high-latitude fish was 1.6 times greater. Taken together, these two results provide preliminary evidence for countergradient variation in digestive rates of salmonids in response to variation in growth opportunity. The data support our previous work on the same two populations showing differences in growth rates, and underlie one of the possible mechnisms leading to more rapid growth of the high-latitude fish when both populations are reared in a common environment.