Phylogenetic analysis informed by geological history supports multiple, sequential invasions of the Mediterranean Basin by the angiosperm family Araceae

Despite the remarkable species richness of the Mediterranean flora and its well-known geological history, few studies have investigated its temporal and spatial origins. Most importantly, the relative contribution of geological processes and long-distance dispersal to the composition of contemporary Mediterranean biotas remains largely unknown. We used phylogenetic analyses of sequences from six chloroplast DNA markers, Bayesian dating methods, and ancestral area reconstructions, in combination with paleogeographic, paleoclimatic, and ecological evidence, to elucidate the time frame and biogeographic events associated with the diversification of Araceae in the Mediterranean Basin. We focused on the origin of four species, Ambrosina bassii, Biarum dispar, Helicodiceros muscivorus, Arum pictum, subendemic or endemic to Corsica, Sardinia, and the Balearic Archipelago. The results support two main invasions of the Mediterranean Basin by the Araceae, one from an area connecting North America and Eurasia in the Late Cretaceous and one from the Anatolian microplate in western Asia during the Late Eocene, thus confirming the proposed heterogeneous origins of the Mediterranean flora. The subendemic Ambrosina bassii and Biarum dispar likely diverged sympatrically from their widespread Mediterranean sister clades in the Early-Middle Eocene and Early-Middle Miocene, respectively. Combined evidence corroborates a relictual origin for the endemic Helicodiceros muscivorus and Arum pictum, the former apparently representing the first documented case of vicariance driven by the initial splitting of the Hercynian belt in the Early Oligocene. A recurrent theme emerging from our analyses is that land connections and interruptions, caused by repeated cycles of marine transgressions-regressions between the Tethys and Paratethys, favored geodispersalist expansion of biotic ranges from western Asia into the western Mediterranean Basin and subsequent allopatric speciation at different points in time from the Late Eocene to the Late Oligocene.     

Oxidation as a crucial reaction for cholesterol to induce tissue degeneration: CD36 overexpression in human promonocytic cells treated with a biologically relevant oxysterol mixture

Oxidative stress, inflammation and altered cholesterol metabolism and levels are among the pathogenetic mechanisms of cognitive impairment that may accompany aging. Within the research area of hypercholesterolemia and age-related disease processes, the molecular mechanisms of cholesterol interaction with the inflammatory cells of the macrophage lineage are yet to be elucidated. We thus investigated the effect of both non-oxidized and oxidized cholesterol on monocytic cell differentiation and foam cell formation, as it occurs within vascular lesions during progression of atherosclerosis. In vitro experiments performed on human U937 promonocytic cells showed that a biologically representative mixture of oxysterols markedly stimulated CD36 expression and synthesis. In contrast, non-oxidized cholesterol did not exert any effect on CD36 mRNA and protein levels. Furthermore, the oxysterol-induced up-regulation of CD36 appeared to be based on the subsequent activation of protein kinase Cdelta (PKCdelta), extracellular signal-regulated kinase 1/2 (ERK1/2) and peroxisome proliferator-activated receptor gamma (PPARgamma). Cells overexpressing CD36 were indeed able to actively take up oxidized low-density lipoproteins, and become foam cells. The essential role of ERK pathway and CD36 receptor in oxysterol-induced foam cell formation was proved by the prevention of the latter event when monocytic cells were incubated in the presence of MEK1/2 selective inhibitor or anti-CD36 specific antibody. These experimental findings point to cholesterol oxidation as an essential reaction for this sterol to exert cellular stress and tissue damage in age-related diseases in which inflammation represents a main driving force.     

Distinct immunohistochemical localization in Kuru plaques using novel anti-prion protein antibodies

By immunizing Prnp-knockout mice with synthetic polypeptides, a panel of mAbs directed to bovine PrP(C) was obtained. The mAb panel was characterized by the ELISA method, where synthetic polypeptides were used for epitope mapping. Different reactivity patterns were identified. The ability of these mAbs to detect abnormal PrP(Sc) in CJD cases was studied by immunohistochemistry. All mAbs were tested for PrP(Sc) in murine, bovine, monkey and human brain tissues. Three mAbs recognized the fragmented PrP epitope in our ELISA. Antibody 1D12 was strongly reactive to ovine and squirrel monkey tissues infected with a scrapie agent, although non-reactive to scrapie-infected mouse tissues. Antibody 2D8 was clearly reactive to type-2 but not type-1 CJD human tissues. Of particular interest was the reactivity of mAb 6C4 with the inner structure of Kuru plaques (peripheral pattern) in a type-2 CJD case and mAb T2, 1D12, 2B11, 2D8, 4B5 and 6G3-2 with the central area (central pattern). The fact that different anti-PrP mAbs possess distinct staining properties suggests that the PrP(c) to PrP(Sc) conversion might involve a multiple-step process.     

Expression and purification of isotopically labeled peptide inhibitors and substrates of cAMP-dependant protein kinase A for NMR analysis

Extensive X-ray crystallographic studies carried out on the catalytic-subunit of protein kinase A (PKA-C) enabled the atomic characterization of inhibitor and/or substrate peptide analogues trapped at its active site. Yet, the structural and dynamic transitions of these peptides from the free to the bound state are missing. These conformational transitions are central to understanding molecular recognition and the enzymatic cycle. NMR spectroscopy allows one to study these phenomena under functionally relevant conditions. However, the amounts of isotopically labeled peptides required for this technique present prohibitive costs for solid-phase peptide synthesis. To enable NMR studies, we have optimized both expression and purification of isotopically enriched substrate/inhibitor peptides using a recombinant fusion protein system. Three of these peptides correspond to the cytoplasmic regions of the wild-type and lethal mutants of the membrane protein phospholamban, while the fourth peptide correspond to the binding epitope of the heat-stable protein kinase inhibitor (PKI_5–24). The target peptides were fused to the maltose binding protein (MBP), which is further purified using a His₆ tag approach. This convenient protocol allows for the purification of milligram amounts of peptides necessary for NMR analysis.     

Cardiac and skeletal muscle defects in a mouse model of human Barth syndrome

Barth syndrome is an X-linked genetic disorder caused by mutations in the tafazzin (taz) gene and characterized by dilated cardiomyopathy, exercise intolerance, chronic fatigue, delayed growth, and neutropenia. Tafazzin is a mitochondrial transacylase required for cardiolipin remodeling. Although tafazzin function has been studied in non-mammalian model organisms, mammalian genetic loss of function approaches have not been used. We examined the consequences of tafazzin knockdown on sarcomeric mitochondria and cardiac function in mice. Tafazzin knockdown resulted in a dramatic decrease of tetralinoleoyl cardiolipin in cardiac and skeletal muscles and accumulation of monolysocardiolipins and cardiolipin molecular species with aberrant acyl groups. Electron microscopy revealed pathological changes in mitochondria, myofibrils, and mitochondrion-associated membranes in skeletal and cardiac muscles. Echocardiography and magnetic resonance imaging revealed severe cardiac abnormalities, including left ventricular dilation, left ventricular mass reduction, and depression of fractional shortening and ejection fraction in tafazzin-deficient mice. Tafazzin knockdown mice provide the first mammalian model system for Barth syndrome in which the pathophysiological relationships between altered content of mitochondrial phospholipids, ultrastructural abnormalities, myocardial and mitochondrial dysfunction, and clinical outcome can be completely investigated.     

Spoilage-related activity of Carnobacterium maltaromaticum strains in air-stored and vacuum-packed meat

One hundred three isolates of Carnobacterium spp. from raw meat were analyzed by random amplification of polymorphic DNA (RAPD) and PCR and were identified by 16S rRNA gene sequencing. Forty-five strains of Carnobacterium maltaromaticum were characterized for their growth capabilities at different temperatures, NaCl concentrations, and pH values and for in vitro lipolytic and proteolytic activities. Moreover, their spoilage potential in meat was investigated by analyzing the release of volatile organic compounds (VOCs) in meat stored in air or vacuum packs. Almost all the strains were able to grow at 4, 10, and 20°C, at pH values of 6 to 9, and in the presence of 2.5% NaCl. The release of VOCs by each strain in beef stored at 4°C in air and vacuum packs was evaluated by headspace solid-phase microextraction (HS-SPME)-gas chromatography-mass spectrometry (GC-MS) analysis. All the meat samples inoculated and stored in air showed higher numbers of VOCs than the vacuum-packed meat samples. Acetoin, 1-octen-3-ol, and butanoic acid were the compounds most frequently found under both storage conditions. The contaminated meat samples were evaluated by a sensory panel; the results indicated that for all sensory odors, no effect of strain was significant (P > 0.05). The storage conditions significantly affected (P < 0.05) the perception of dairy, spoiled-meat, and mozzarella cheese odors, which were more intense in meat stored in air than in vacuum packs but were never very intense. In conclusion, different strains of C. maltaromaticum can grow efficiently in meat stored at low temperatures both in air and in vacuum packs, producing volatile molecules with low sensory impacts, with a negligible contribution to meat spoilage overall.     

Unexpectedly low mutation rates in beta-myosin heavy chain and cardiac myosin binding protein genes in Italian patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disease. Fourteen sarcomeric and sarcomere‐related genes have been implicated in HCM etiology, those encoding β‐myosin heavy chain (MYH7) and cardiac myosin binding protein C (MYBPC3) reported as the most frequently mutated: in fact, these account for around 50% of all cases related to sarcomeric gene mutations, which are collectively responsible for approximately 70% of all HCM cases. Here, we used denaturing high‐performance liquid chromatography followed by bidirectional sequencing to screen the coding regions of MYH7 and MYBPC3 in a cohort (n = 125) of Italian patients presenting with HCM. We found 6 MHY7 mutations in 9/125 patients and 18 MYBPC3 mutations in 19/125 patients. Of the three novel MYH7 mutations found, two were missense, and one was a silent mutation; of the eight novel MYBPC3 mutations, one was a substitution, three were stop codons, and four were missense mutations. Thus, our cohort of Italian HCM patients did not harbor the high frequency of mutations usually found in MYH7 and MYBPC3. This finding, coupled to the clinical diversity of our cohort, emphasizes the complexity of HCM and the need for more inclusive investigative approaches in order to fully understand the pathogenesis of this disease. J. Cell. Physiol. 226: 2894–2900, 2011. © 2011 Wiley‐Liss, Inc.     

Rapid and reliable identification of Staphylococcus equorum by a species-specific PCR assay targeting the sodA gene

Rapid and reliable identification of Staphylococcus (S.) equorum was achieved by species-specific PCR assays. A set of primers targeting the manganese-dependent superoxide dismutase (sodA) gene of S.equorum was designed. Species-specificity of the primer set was evaluated by using a total of 112 strains (including 27 reference strains of the DSM collection), representing 26 different species of the genus Staphylococcus, 3 species of the genus Kocuria, and different strains of Macrococcus caseolyticus. By using primers SdAEqF and SdAEqR the expected PCR fragment was obtained only when DNA from S. equorum strains was used as template. The rapidity (about 4 h from DNA isolation to results) and reliability of the PCR procedures established suggests that the method may be profitably applied for specific detection and identification of S. equorum strains.     

Is time on our side? Strengthening the link between field efforts and conservation needs

The collection and organization of distributional data is the first crucial stage of any conservation planning action: therefore the decline in field research has implications in both the systematic, floristic and conservation fields. The aim of this paper is to analyze the effects of data updating on conservation planning and priorities. Focusing on the short time frame ranging from 2006 to 2011, we present a case study showing the rate of increase of collected data (taxa and records) and the consequential effects on the definition of areas of priority interest for plant conservation (Important Plant Areas—IPAs). We gathered data on a total of 193 taxa and 849 records with a mean rate of increase of +97 % for taxa and +166 % for records (2006/2011). This increase caused a positive rate of change in high ranking cells (+78 %) defining IPAs, while the number of low ranking cells and no data cells slightly decreased (?12 and ?8 %, respectively). Our results suggest that specific investment to complete the knowledge on the distribution of selected taxa (e.g. 193 taxa represent the 7.5 % of the total vascular flora of Sardinia) would dramatically reduce both the Linnean and Wallacean shortfalls and would allow robust conservation programs to preserve the diversity of the island. Updating the IPAs on a regular basis is a good example of a process that has a low impact as well as a big potential gain especially when field research can only be performed with low intensity and small monetary investments.