A reconstruction of Palaeo‐Macaronesia,with particular reference to the long‐term biogeography of the Atlantic island laurel forests

Macaronesia is a biogeographical region comprising five Atlantic Oceanic archipelagos: the Azores, Madeira, Selvagen (Savage Islands), Canaries and Cape Verde. It has strong affinities with the Atlantic coast of the Iberian Peninsula and the north‐western fringes of Africa. This paper re‐evaluates the biogeographical history and relationships of Macaronesia in the light of geological evidence, which suggests that large and high islands may have been continuously available in the region for very much longer than is indicated by the maximum surface area of the oldest current island (27 Ma) – possibly for as long as 60 million years. We review this literature, attempting a sequential reconstruction of Palaeo‐Macaronesia from 60 Ma to the present. We consider the implications of these geological dynamics for our understanding of the history of colonization of the present islands of Macaronesia. We also evaluate the role of these archipelagos as stepping stones and as both repositories of palaeo‐endemic forms and crucibles of neo‐endemic radiations of plant and animal groups. Our principal focus is on the laurel forest communities, long considered impoverished relicts of the Palaeotropical Tethyan flora. This account is therefore contextualized by reference to the long‐term climatic and biogeographical history of Southern Europe and North Africa and by consideration of the implications of changes in land–sea configuration, climate and ocean circulation for Macaronesian biogeography. We go on to provide a synthesis of the more recent history of Macaronesian forests, which has involved a process of impoverishment of the native elements of the biota that has accelerated since human conquest of the islands. We comment briefly on these processes and on the contemporary status and varied conservation opportunities and threats facing these forests across the Macaronesian biogeographical region.     

Identification of the Plasmodium falciparum rhoptry neck protein 5 (PfRON5)

In this study a gene for a drought stress-inducible putative membrane protein was cloned and characterised from root tissue of wild emmer wheat. Sequence analysis indicated that the protein is a member of the widespread but hitherto uncharacterised TMPIT (transmembrane protein inducible by TNF-α) family, so it was labelled TdicTMPIT1. Real-time RT-PCR showed that the TdicTMPIT1 gene is upregulated on drought stress in drought-tolerant wild emmer wheat, but not in a drought-sensitive accession or in cultivated durum wheat. The TdicTMPIT1 product was predicted to be a membrane protein with four transmembrane helices. The protein was expressed and analysed in Escherichia coli and Saccharomyces cerevisiae. Cellular localisation of the protein in the cell was also investigated using an eGFP-tagged form of the protein in S. cerevisiae. Results obtained by confocal laser microscopy indicated that the TdicTMPIT1 tagged with GFP was localised in a membraneous compartment. It is concluded that TdicTMPIT1 is a membrane protein associated with the drought stress response in wild emmer wheat, and so it may be useful for the improvement of modern wheat genotypes. Members of this protein family in other organisms are proposed also to be involved in stress responses.     

Protective role of ghrelin against carbon tetrachloride (CCl₄)-induced coagulation disturbances in rats

Recent data indicate that ghrelin has protective effects in different organs and cell types including the pancreas, heart, and gastrointestinal tract. The purpose of this study was to determine whether ghrelin plays a protective role against CCl₄-induced coagulation disturbances in rats.Fourty male Sprague–Dawley rats were equally divided into four groups including group 1 (1 ml physiological saline s.c., for 5 days), group 2 (CCl₄, i.p., single dose of 1.6 g/kg), group 3 (ghrelin, s.c., 10 nmol/kg/day, for 5 days) and group 4 (ghrelin, 10 nmol/kg/day, for 5 days plus CCl₄, i.p., single dose of 1.6 g/kg on the 5th day). Fibrinogen level, activated partial thromboplastin time (aPTT), prothrombin time (PT), platelet counts and alanine transaminase (ALT) activity were evaluated. The values of PT, aPTT and ALT activity were increased (p < 0.05), while fibrinogen level was decreased (p < 0.05) due to CCl4 treatment alone. Pre-treatment with ghrelin prior to the administration of CCl₄ reduced (p < 0.05) PT, aPTT and ALT values and increased (p < 0.05) fibrinogen level when compared with CCl₄-treated only group. The results of this study suggest that exogenously administered ghrelin may play a protective role against CCl₄-induced coagulation disturbances in rats.     

Effects of selected fertilizers on the life history of Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B

We tested the effects among a purportedly sustainable water-soluble fertilizer, a conventional water-soluble fertilizer, an alternation of these, a controlled-release fertilizer, and a clear water control on the life-history traits of sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae; =Bemisia argentifolii Bellows & Perring) biotype B reared on poinsettia (Euphorbia pulcherrima Willdenow ex Klotzch). Free amino acids in petioles were measured to estimate plant nutrient assimilation and phloem nutritional quality for B. tabaci biotype B. The sustainable fertilizer produced plants with the highest concentration of amino acids. In contrast, fecundity of whiteflies was lowest in plants treated with the sustainable fertilizer and the water control. The relationship between total amino acids in phloem and survival was significantly quadratic, with the highest survival at intermediate levels. Fecundity, however, was negatively correlated with total amino acid content of the maternal host plant. Variation in total amino acid concentration in petioles of plants treated within fertilizer treatments makes it difficult to predict whether a particular fertilizer will produce plants with enough amino acids to deleteriously affect both survivorship and fecundity and yet yield a plant of good quality. Despite this limitation, we can conclude that the use of this sustainable fertilizer will not cause increases in whitefly populations relative to plants fertilized with water-soluble and slow-release fertilizers that deliver the same level of nitrogen to the plant.     

Identification of a novel neuropathogenic Theiler's murine encephalomyelitis virus

Theiler's murine encephalitis viruses (TMEV) are divided into two subgroups based on their neurovirulence. Persistent strains resemble Theiler's original viruses (referred to as the TO subgroup), which largely induce a subclinical polioencephalomyelitis during the acute phase of the disease and can persist in the spinal cord of susceptible animals, inducing a chronic demyelinating disease. In contrast, members of the neurovirulent subgroup cause an acute encephalitis characterized by the rapid onset of paralysis and death within days following intracranial inoculation. We report herein the characterization of a novel neurovirulent strain of TMEV, identified using pyrosequencing technology and referred to as NIHE. Complete coverage of the NIHE viral genome was obtained, and it shares <90% nucleotide sequence identity to known TMEV strains irrespective of subgroup, with the greatest sequence variability being observed in genes encoding the leader and capsid proteins. The histopathological analysis of infected brain and spinal cord demonstrate inflammatory lesions and neuronal necrosis during acute infection with no evidence of viral persistence or chronic disease. Intriguingly, genetic analysis indicates the putative expression of the L protein, considered a hallmark of strains within the persistent subgroup. Thus, the identification and characterization of a novel neurovirulent TMEV strain sharing features previously associated with both subgroups will lead to a deeper understanding of the evolution of TMEV strains and new insights into the determinants of neurovirulence.     

DRG Axon Elongation and Growth Cone Collapse Rate Induced by Sema3A are Differently Dependent on NGF Concentration

Regeneration of embryonic and adult dorsal root ganglion (DRG) sensory axons is highly impeded when they encounter neuronal growth cone-collapsing factor semaphorin3A (Sema3A). On the other hand, increasing evidence shows that DRG axon’s regeneration can be stimulated by nerve growth factor (NGF). In this study, we aimed to evaluate whether increased NGF concentrations can counterweight Sema3A-induced inhibitory responses in 15-day-old mouse embryo (E15) DRG axons. The DRG explants were grown in Neurobasal-based medium with different NGF concentrations ranging from 0 to 100 ng/mL and then treated with Sema3A at constant 10 ng/mL concentration. To evaluate interplay between NGF and Sema3A number of DRG axons, axon outgrowth distance and collapse rate were measured. We found that the increased NGF concentrations abolish Sema3A-induced inhibitory effect on axon outgrowth, while they have no effect on Sema3A-induced collapse rate.     

Association of obesity with rs1421085 and rs9939609 polymorphisms of FTO gene

The aim of this study is to investigate the genetic influence of polymorphisms in fat mass and obesity associated (FTO) gene on a sample of obese subjects and controls. Obesity is an epidemic all over the world. Several polymorphisms in the first intron of FTO gene have been associated with common forms of human obesity. In this research rs1421085 and rs9939609 polymorphisms of FTO gene were genotyped in 190 obese patients with a BMI ≥30 kg/m² (Body Mass Index) and 97 healthy controls with a BMI of 18.5–24.9. Genotyping of SNPs was performed by real-time polymerase chain reaction. Body composition was established with bioelectric impedance analysis. Waist-to-hip ratio was determined for all participants. There were no significant differences (P > 0.05) between obese cases and controls in terms of genotype frequencies of rs1421085 and rs9939609 polymorphisms in our study. Also there were no significant correlations between genotypes and obesity related (anthropometric-body composition) parameters (P > 0.05).     

μABC: a systematic microsecond molecular dynamics study of tetranucleotide sequence effects in B-DNA

We present the results of microsecond molecular dynamics simulations carried out by the ABC group of laboratories on a set of B-DNA oligomers containing the 136 distinct tetranucleotide base sequences. We demonstrate that the resulting trajectories have extensively sampled the conformational space accessible to B-DNA at room temperature. We confirm that base sequence effects depend strongly not only on the specific base pair step, but also on the specific base pairs that flank each step. Beyond sequence effects on average helical parameters and conformational fluctuations, we also identify tetranucleotide sequences that oscillate between several distinct conformational substates. By analyzing the conformation of the phosphodiester backbones, it is possible to understand for which sequences these substates will arise, and what impact they will have on specific helical parameters.     

Staphylococcus aureus Manganese Transport Protein C (MntC) Is an Extracellular Matrix- and Plasminogen-Binding Protein

Infections caused by Staphylococcus aureus – particularly nosocomial infections - represent a great concern. Usually, the early stage of pathogenesis consists on asymptomatic nasopharynx colonization, which could result in dissemination to other mucosal niches or invasion of sterile sites, such as blood. This pathogenic route depends on scavenging of nutrients as well as binding to and disrupting extracellular matrix (ECM). Manganese transport protein C (MntC), a conserved manganese-binding protein, takes part in this infectious scenario as an ion-scavenging factor and surprisingly as an ECM and coagulation cascade binding protein, as revealed in this work. This study showed a marked ability of MntC to bind to several ECM and coagulation cascade components, including laminin, collagen type IV, cellular and plasma fibronectin, plasminogen and fibrinogen by ELISA. The MntC binding to plasminogen appears to be related to the presence of surface-exposed lysines, since previous incubation with an analogue of lysine residue, ε-aminocaproic acid, or increasing ionic strength affected the interaction between MntC and plasminogen. MntC-bound plasminogen was converted to active plasmin in the presence of urokinase plasminogen activator (uPA). The newly released plasmin, in turn, acted in the cleavage of the α and β chains of fibrinogen. In conclusion, we describe a novel function for MntC that may help staphylococcal mucosal colonization and establishment of invasive disease, through the interaction with ECM and coagulation cascade host proteins. These data suggest that this potential virulence factor could be an adequate candidate to compose an anti-staphylococcal human vaccine formulation.