Flying over water: how “On bird species diversity” influenced aquatic ecology

Habitat complexity has long been known to influence animal community structure by increasing the number of available habitats. Fifty years have passed since MacArthur brothers published the seminal paper “On bird species diversity”, which revolutionized studies of habitat structure. This paper first evidenced and quantified the relationship between species diversity (birds) and habitat structural complexity (the number of stratified layers of landscape vegetation). In this article, we aim to pay homage to R. H. MacArthur’s contribution and to briefly analyze the citation history and influence of “On bird species diversity”, focusing primarily on aquatic studies. We searched for all papers that cited “On bird species diversity” on Thomson Reuters (ISI—Web of Knowledge) and analyzed them for temporal citation trends. In addition, considering only aquatic papers, we explored whether and how habitat complexity was measured, as well as the ecological organization level, attributes of organisms, taxonomic groups and study design (observational or experimental). “On bird species diversity” citations increased over time, but this paper was less cited by limnologists compared to terrestrial and marine scientists. The majority of investigations in aquatic ecosystems quantified habitat complexity, but few used mathematical modeling. The high number of citations, which continues to increase, shows the great influence of “On bird species diversity” on ecological studies and typifies it as a classic in the ecological literature. However, the low citation frequency found in papers devoted to freshwater ecosystems indicates that limnologists in general neglect this original contribution in studies of habitat complexity.     

Affective Priming Using Facial Expressions Modulates Liking for Abstract Art

We examined the influence of affective priming on the appreciation of abstract artworks using an evaluative priming task. Facial primes (showing happiness, disgust or no emotion) were presented under brief (Stimulus Onset Asynchrony, SOA = 20ms) and extended (SOA = 300ms) conditions. Differences in aesthetic liking for abstract paintings depending on the emotion expressed in the preceding primes provided a measure of the priming effect. The results showed that, for the extended SOA, artworks were liked more when preceded by happiness primes and less when preceded by disgust primes. Facial expressions of happiness, though not of disgust, exerted similar effects in the brief SOA condition. Subjective measures and a forced-choice task revealed no evidence of prime awareness in the suboptimal condition. Our results are congruent with findings showing that the affective transfer elicited by priming biases evaluative judgments, extending previous research to the domain of aesthetic appreciation.     

The role of fire in terrestrial vertebrate richness patterns

Productivity is strongly associated with terrestrial species richness patterns, although the mechanisms underpinning such patterns have long been debated. Despite considerable consumption of primary productivity by fire, its influence on global diversity has received relatively little study. Here we examine the sensitivity of terrestrial vertebrate biodiversity (amphibians, birds and mammals) to fire, while accounting for other drivers. We analyse global data on terrestrial vertebrate richness, net primary productivity, fire occurrence (fraction of productivity consumed) and additional influences unrelated to productivity (i.e., historical phylogenetic and area effects) on species richness. For birds, fire is associated with higher diversity, rivalling the effects of productivity on richness, and for mammals, fire's positive association with diversity is even stronger than productivity; for amphibians, in contrast, there are few clear associations. Our findings suggest an underappreciated role for fire in the generation of animal species richness and the conservation of global biodiversity.     

RAPD fingerprints for identification and for taxonomic studies of elite poplar (Populus spp.) clones

RAPD (Random Amplified Polymorphic DNA) fingerprints have recently been used to estimate genetic and taxonomic relationships in plants. In this study RAPD analysis was performed on 32 clones belonging to different species of the genus Populus. Of these, 25 clones are registered in several countries for commercial use and, altogether, cover almost 50% of the worlds cultivated poplars. DNA was prepared from leaves and amplified by PCR using random oligonucleotide primers. Amplification products were separated by agarose-gel electrophoresis to reveal band polymorphisms. Four primers out of the 18 tested, were selected on the basis of the number and frequency of the polymorphisms produced. With these a total of 120 different DNA bands were reproducibly obtained, 92% of which were polymorphic. The polymorphisms were scored and used in band-sharing analyses to identify genetic relationships. With a few but interesting exceptions, these are consistent with the present taxonomy of the genus Populus and with the known predigrees of cultivated poplars. Moreover, the results show that RAPD analysis allows one to discriminate among all tested clones and can, therefore, be recommended as a convenient tool to defend plant breeders rights.     

Defining the importance of landscape metrics for large branchiopod biodiversity and conservation: the case of the Iberian Peninsula and Balearic Islands

The deficiency in the distributional data of invertebrate taxa is one of the major impediments acting on the bias towards the low awareness of its conservation status. The present study sets a basic framework to understand the large branchiopods distribution in the Iberian Peninsula and Balearic Islands. Since the extensive surveys performed in the late 1980s, no more studies existed updating the information for the whole studied area. The present study fills the gap, gathering together all available information on large branchiopods distribution since 1995, and analysing the effect of human population density and several landscape characteristics on their distribution, taking into consideration different spatial scales (100 m, 1 km and 10 km). In overall, 28 large branchiopod taxa (17 anostracans, 7 notostracans and 4 spinicaudatans) are known to occur in the area. Approximately 30% of the sites hosted multiple species, with a maximum of 6 species. Significant positive co-occurring species pairs were found clustered together, forming 4 different associations of large branchiopod species. In general, species clustered in the same group showed similar responses to analysed landscape characteristics, usually showing a better fit at higher spatial scales.     

DNA SEQUENCE DATA DEMONSTRATE THE POLYPHYLY OF THE GENUS CYSTOSEIRA AND OTHER SARGASSACEAE GENERA (PHAEOPHYCEAE)1

Phylogenetic relationships in the Sargassaceae were explored using three DNA markers, and the monophyly of its genera was challenged. Nineteen out of 24 currently recognized genera were sampled, representing 63 species. The variable mt23S‐tRNA Val intergenic spacer could only be aligned within genera and could not be used to infer intergeneric relationships. The partial mt23S was also useful to delineate genera and was alignable at the family level but provided few informative characters. Analysis of mt23S DNA sequences together with chloroplast‐encoded psbA sequences resulted in a better resolved phylogeny. Hormophysa was the first genus to branch off within the Sargassaceae, followed by Myriodesma; then the three genera Caulocystis, Carpoglossum, and Scaberia in unresolved order; and then Acrocarpia. The other taxa studied here were divided over three major clades, but there was no branch support for the monophyly of two of these. The genera Bifurcaria, Cystoseira, Halidrys, and Sargassum appeared polyphyletic. The following taxonomic changes are proposed: a new genus Brassicophycus for Bifurcaria brassicaeformis (Kützing) E. S. Barton; reinstatement of the genus Sargassopsis for Sargassum decurrens (R. Brown ex Turner) C. Agardh; reinstatement of the genus Sirophysalis for Indo‐Pacific Cystoseira trinodis (Forsskål) C. Agardh; reinstatement of the genus Polycladia for the western Indian Ocean species Cystoseira indica (Thivy et Doshi) Mairh, Cystoseira myrica (S. G. Gmelin) C. Agardh, and Acystis heinii Schiffner; and reinstatement of the genus Stephanocystis for the North Pacific Cystoseira species and Halidrys dioica N. L. Gardner. The European Cystoseira species should be split into three genera, but no name changes are proposed yet, because diagnostic characters were found only for the clade including the type species. Some evolutionary trends could be discerned from the mt23S + psbA phylogeny.     

Spatial Distribution of Helicobacter spp. in the Gastrointestinal Tract of Dogs

Background:  In dogs, the gastric Helicobacter spp. have been well studied, but there is little information regarding the other parts of the alimentary system. We sought to determine the spatial distribution of Helicobacter spp. in the gastrointestinal tract and the hepatobiliary system of dogs using culture-independent methods.
Materials and methods:  Samples of stomach, duodenum, ileum, cecum, colon, pancreas, liver, and bile from six dogs were evaluated for Helicobacter spp. by genus, gastric, and enterohepatic Helicobacter spp. Polymerase chain reaction, 16S rRNA gene sequence analysis, immunohistochemistry, and fluorescence in situ hybridization (FISH).
Results:  In the stomach, Helicobacter spp. DNA was detected in all six dogs, with H. bizzozeronii and H. felis identified by specific polymerase chain reaction. Helicobacter organisms were localized within the surface mucus, the lumen of gastric glands, and inside parietal cells. The small intestine harbored gastric and enterohepatic Helicobacter spp. DNA/antigen in low amounts. In the cecum and colon, Helicobacter spp. DNA, with highest similarity to H. bilis /flexispira taxon 8, H. cinaedi , and H. canis, was detected in all six dogs. Helicobacter organisms were localized at the mucosal surface and within the crypts. Gastric Helicobacter spp. DNA was detected occasionally in the large intestine, but no gastric Helicobacter spp. were present in clone libraries or detected by FISH.
Conclusions:  This study demonstrates that in addition to the stomach, the large intestine of dogs is also abundantly colonized by Helicobacter spp. Additional studies are necessary to investigate the association between enterohepatic Helicobacter spp. and presence of intestinal inflammatory or proliferative disorders in dogs.     

Separate and Combined Effects of DNMT and HDAC Inhibitors in Treating Human Multi-Drug Resistant Osteosarcoma HosDXR150 Cell Line

Understanding the molecular mechanisms underlying multi-drug resistance (MDR) is one of the major challenges in current cancer research. A phenomenon which is common to both intrinsic and acquired resistance, is the aberrant alteration of gene expression in drug-resistant cancers. Although such dysregulation depends on many possible causes, an epigenetic characterization is considered a main driver. Recent studies have suggested a direct role for epigenetic inactivation of genes in determining tumor chemo-sensitivity. We investigated the effects of the inhibition of DNA methyltransferase (DNMT) and hystone deacethylase (HDAC), considered to reverse the epigenetic aberrations and lead to the re-expression of de novo methylated genes in MDR osteosarcoma (OS) cells. Based on our analysis of the HosDXR150 cell line, we found that in order to reduce cell proliferation, co-treatment of MDR OS cells with DNMT (5-Aza-dC, DAC) and HDAC (Trichostatin A, TSA) inhibitors is more effective than relying on each treatment alone. In re-expressing epigenetically silenced genes induced by treatments, a very specific regulation takes place which suggests that methylation and de-acetylation have occurred either separately or simultaneously to determine MDR OS phenotype. In particular, functional relationships have been reported after measuring differential gene expression, indicating that MDR OS cells acquired growth and survival advantage by simultaneous epigenetic inactivation of both multiple p53-independent apoptotic signals and osteoblast differentiation pathways. Furthermore, co-treatment results more efficient in inducing the re-expression of some main pathways according to the computed enrichment, thus emphasizing its potential towards representing an effective therapeutic option for MDR OS.     

15(S)-HETE modulates LTB(4) production and neutrophil chemotaxis in chronic bronchitis

We evaluated the levels of15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] and the expression of15-lipoxygenase (15-LO) mRNA in induced sputum obtained from 10 controland 15 chronic bronchitis subjects. 15(S)-HETE was evaluated by reversephase high-performance liquid chromatography separationfollowed by specific RIA. 15-LO mRNA expression was determined byprimed in situ labeling. The levels of both soluble and cell-associated 15(S)-HETE resulted significantly higher in chronic bronchitis than incontrol subjects. The percentage of cells expressing 15-LO mRNA wassignificantly higher in chronic bronchitis than in control subjects(P < 0.01). Double staining for specific cell typemarkers and 15-LO mRNA showed macrophages and neutrophils positive for 15-LO, whereas similar staining of peripheral blood neutrophils did notshow evidence for 15-LO expression, suggesting that expression of 15-LOin neutrophils takes place on migration into the airways. Because15(S)-HETE inversely correlated with the percentage of neutrophils insputum of chronic bronchitis subjects, we studied the effect of15(S)-HETE on leukotriene B₄ (LTB₄) productionin vitro and evaluated the concentration of LTB₄ in inducedsputum and the contribution of LTB₄ to the chemotacticactivity of induced sputum samples ex vivo. The results obtainedindicate that macrophages and neutrophils present within the airways ofchronic bronchitis subjects express 15-LO mRNA; increased basal levelsof 15(S)-HETE may contribute to modulate, through the inhibition of5-lipoxygenase metabolites production, neutrophil infiltration andairway inflammation associated with chronic bronchitis.