Genomic insights into acute inflammatory lung injury

Acute lung injury (ALI) is a devastating syndrome (usually associated with sepsis) that represents a major healthcare burden in the United States. We have focused our studies on unraveling the genetic underpinnings of this syndrome utilizing a candidate gene approach to identify novel genes for ALI susceptibility. Two novel genes identified by this approach include pre-B cell colony-enhancing factor (PBEF) and the gene for myosin light chain kinase (MLCK). PBEF protein levels were elevated in human bronchoalveolar lavage and serum samples from patients with ALI, and DNA sequencing identified two single nucleotide polymorphisms in the PBEF promoter (T-1001G, C-1543T) that were overrepresented in patients with sepsis-induced ALI. More recently, we found MLCK single polymorphisms and haplotypes to be associated with human ALI with unique variants observed in African-Americans with ALI. Thus genomic and genetic approaches represent powerful strategies in the identification of novel candidate genes and potential targets for ALI therapies.     

Features of crossing-over in virus-infected tomato

The evidence of increased crossing over rate in tomato hybrids infected with TAV (Tomato aspermy virus), PVX (Potato virus X), TMV (Tobacco mosaic virus), TMV+PVX indicates the recombinogenic effect of viral infection. Cytological studies of the early diakinesis in healthy and virus-infected tomato revealed significant changes in chiasma number and position. The most significant changes were established for bivalents with two interstitial chiasmata and with one terminal and one interstitial. The data obtained indicate redistribution of the chiasmata position and induction of additional exchanges. The virus-induced recombination is segment-specific and depends on the host plant genotype, virus infection and the interaction between them.     

Cadmium exposure modifies lactotrophs activity associated to genomic and morphological changes in rat pituitary anterior lobe

Cadmium (Cd) is widely used in industrial applications and is an important contaminant of agricultural products. As an endocrine disruptor, Cd modifies the hormone release of pituitary anterior lobe (PAL). This work was undertaken to evaluate a possible association between phospholipase D (PLD) and prolactin mRNA expressions and the activity of lactotrophs and folliculostellate cells (FSC) in PAL of Cd exposed adult male Wistar rats (Cd, 0.133 mM per liter for 2 months). The PALs were submitted to immunohistochemical and morphometric analysis to determine the percentage of lactotrophs (PRL-ir) and FSC (S-100-ir). Cultured PAL cells were stained with Hoechst 33258 to determine the presence of alterations in nuclear morphology consistent with apoptosis. The expressions of PLD and prolactin mRNA were assessed by RT-PCR. Cd treated rats showed a decrease of PLD mRNA levels that can be associated to both high number of apoptotic cells and increase of S-100 protein expression in FSC. Cd decreased prolactin mRNA expression, number of lactotrophs and percentage of PRL-ir suggesting a low availability of prolactin to be secreted from PAL. Cd modifies the lactotrophs activity of pituitary gland through biochemical, genomic and morphological changes and contributes directly or indirectly to the levels of serum prolactin.     

The relationship between fish assemblages and the helminth communities of a prey fish, in a group of small shallow lakes

Galaxias maculatus (small puyen) is an abundant native fish distributed in lakes and rivers of the Patagonia, and it is the frequent prey of other fishes, fish-eating birds, and mammals. Previous studies have shown that it is parasitized by 33 metazoan species and that the richness and composition of the parasite communities vary between lakes. The aim of the present work was to analyze the relationship between the composition of fish assemblages and the helminth component community structure of G. maculatus . Ten environmentally similar, small, shallow lakes, belonging to the Nahuel Huapi Lake basin, were chosen because of the differences in the native fish assemblages. Parasite community structure in G. maculatus varied according to the fish assemblage of each lake. The presence of the piscivorous fish Percichthys trucha regularly produced variations in the composition and richness at the component and infracommunity levels, as well as the percentage of autogenic parasite species in G. maculatus .     

Co‐encapsulation of anti‐BCR‐ABL siRNA and imatinib mesylate in transferrin receptor‐targeted sterically stabilized liposomes for chronic myeloid leukemia treatment

Chronic myeloid leukemia (CML) is triggered by the BCR‐ABL oncogene. Imatinib is the first‐line treatment of CML; however imatinib resistance and intolerance have been detected in many patients. Therefore, new therapeutic approaches are required. The present work aimed at the development and application of transferrin receptor (TrfR) targeted liposomes co‐encapsulating anti‐BCR‐ABL siRNA and imatinib at different molar ratios. The encapsulation yields and drug loading of each molecule was evaluated. Anti‐leukemia activity of the developed formulations co‐encapsulating siRNA and imatinib and of the combination of Trf‐liposomes carrying siRNA and free imatinib under two different treatment schedules of pre‐sensitization was assessed. The results obtained demonstrate that the presence of imatinib significantly decreases the encapsulation yields of siRNA, whereas imatinib encapsulation yields are increased by the presence of siRNA. Cytotoxicity assays demonstrate that the formulations co‐encapsulating siRNA and imatinib promote a 3.84‐fold reduction on the imatinib IC₅₀ (from 3.49 to 0.91 µM), whereas a 8.71‐fold reduction was observed for the pre‐sensitization protocols (from 42.7 to 4.9 nM). It was also observed that the formulations with higher siRNA to imatinib molar ratios promote higher cell toxicity. Thus, the present work describes a novel triple targeting strategy with one single system: cellular targeting (through the targeting ligand, transferrin) and molecular targeting at the BCR‐ABL mRNA and Bcr‐Abl protein level. Biotechnol. Bioeng. 2010;107: 884–893. © 2010 Wiley Periodicals, Inc.     

First confirmed case of pseudocopulation in terrestrial orchids of South America: Pollination of Geoblasta pennicillata (Orchidaceae) by Campsomeris bistrimacula (Hymenoptera, Scoliidae)

The attraction of male pollinating insects by sexual deception is known for several orchids from the Mediterranean, Australia, South Africa and South America. The sexual delusion may be so enticing in some species that it elicits males to attempt copulation with insect-like structures of the labellum. Pollination by such a pseudocopulation mechanism is reported here for the terrestrial orchid Geoblasta penicillata (Chloraeinae) from subtropical South America. Observations of the pollination process were carried out in two wild populations 560 km distant from each other. The only pollinators seen in both populations were male Campsomeris bistrimacula (Scoliidae) wasps. They attempted copulation with the insect-like labellum by directing the genitalia to its base whereby pollinia got attached to the dorsal surface of the metasoma. The present case of pseudocopulation, which is in South America the second known and the first recorded in wild populations, represents a striking parallel to the Australian Calochilus campestris also pollinated by male scoliid wasp of the genus Campsomeris.     

Calcium-dependent and -independent interactions of the S100 protein family

The S100 proteins comprise at least 25 members, forming the largest group of EF-hand signalling proteins in humans. Although the proteins are expressed in many tissues, each S100 protein has generally been shown to have a preference for expression in one particular tissue or cell type. Three-dimensional structures of several S100 family members have shown that the proteins assume a dimeric structure consisting of two EF-hand motifs per monomer. Calcium binding to these S100 proteins, with the exception of S100A10, results in an approx. 40 degrees alteration in the position of helix III, exposing a broad hydrophobic surface that enables the S100 proteins to interact with a variety of target proteins. More than 90 potential target proteins have been documented for the S100 proteins, including the cytoskeletal proteins tubulin, glial fibrillary acidic protein and F-actin, which have been identified mostly from in vitro experiments. In the last 5 years, efforts have concentrated on quantifying the protein interactions of the S100 proteins, identifying in vivo protein partners and understanding the molecular specificity for target protein interactions. Furthermore, the S100 proteins are the only EF-hand proteins that are known to form both homo- and hetero-dimers, and efforts are underway to determine the stabilities of these complexes and structural rationales for their formation and potential differences in their biological roles. This review highlights both the calcium-dependent and -independent interactions of the S100 proteins, with a focus on the structures of the complexes, differences and similarities in the strengths of the interactions, and preferences for homo- compared with hetero-dimeric S100 protein assembly.     

Breeding performance,mate fidelity,and nest site fidelity in a long‐lived seabird: behaving against the current?

There is evidence that breeding failure is associated with divorce and dispersal in many bird species. However, deviations from the general pattern “success‐stay/failure‐leave” seem to be common, suggesting that factors other than breeding performance may importantly influence mate and habitat selection. Moreover, variability in response to performance suggests coexistence of different evolutionary strategies of mate and site selection within a population. In this study, we assessed how individuals conform to the success‐stay/failure‐leave pattern in kittiwakes (Rissa tridactyla), and aimed to identify categories of individuals presenting different behavioural patterns. We considered individual attributes (experience, prior residence at the nest site, performance in multiple breeding attempts), pair attributes (arrival asynchrony, timing of failure, pair duration), and productivity in habitat patches. Timing of failure was an important factor. Pair reunion probability was close to 0.5 in failed pairs, but it was consistently higher in early failed than in late failed pairs. Prior residence better explained variability in probability of reunion in failed pairs than pair duration. However, the positive influence of prior residence on the probability of reunion was perceptible only in early failed pairs. Divorce probability in successful pairs increased with arrival asynchrony, and was higher in first‐time than in experienced breeders. Local productivity positively influenced site fidelity probability in early failed birds, but not in late failed ones. Using memory models, we found that dispersal decisions integrate information on individual breeding performance in a temporal scale longer than one year. This study contributed to the identification of relevant states to be considered when addressing mate and nest site choice. Natural selection may operate on slight fitness differences that cannot be detected without high levels of stratification according to the appropriate individual and habitat attributes.     

Fitness consequences for copepods feeding on a red tide dinoflagellate: deciphering the effects of nutritional value, toxicity, and feeding behavior

Phytoplankton exhibit a diversity of morphologies, nutritional values, and potential chemical defenses that could affect the feeding and fitness of zooplankton consumers. However, how phytoplankton traits shape plant–herbivore interactions in the marine plankton is not as well understood as for terrestrial or marine macrophytes and their grazers. The occurrence of blooms of marine dinoflagellates such as Karenia brevis suggests that, for uncertain reasons, grazers are unable to capitalize on, or control, this phytoplankton growth—making these systems appealing for testing mechanisms of grazing deterrence. Using the sympatric copepod Acartia tonsa, we conducted a mixed diet feeding experiment to test whether K. brevis is beneficial, toxic, nutritionally inadequate, or behaviorally rejected as food relative to the palatable and nutritionally adequate phytoplankter Rhodomonas lens. On diets rich in K. brevis, copepods experienced decreased survivorship and decreased egg production per female, but the percentage of eggs that hatched was unaffected. Although copepods showed a 6–17% preference for R. lens over K. brevis on some mixed diets, overall high ingestion rates eliminated the possibility that reduced copepod fitness was caused by copepods avoiding K. brevis, leaving nutritional inadequacy and toxicity as remaining hypotheses. Because egg production was dependent on the amount of R. lens consumed regardless of the amount of K. brevis eaten, there was no evidence that fitness costs were caused by K. brevis toxicity. Copepods limited to K. brevis ate 480% as much as those fed only R. lens, suggesting that copepods attempted to compensate for low food quality with increased quantity ingested. Our results indicate that K. brevis is a poor food for A. tonsa, probably due to nutritional inadequacy rather than toxicity, which could affect bloom dynamics in the Gulf of Mexico where these species co-occur.