Diel vertical migration ofEudiaptomus gracilis during a short summer period

Several aspects of a diel vertical migration (DVM) of adultEudiaptomus gracilis in Lake Maarsseveen (The Netherlands) are described. The period of DVM lasted from the end of May until the middle of August. On May 21, 1989, the population was found divided into a deep dwelling part and a part in the upper five meter. Large shoals of juvenile perch were observed in the open water for the first time. On June 7, the whole population was down below 10 m and concentrated in a zone of high chlorphyll-a concentrations. One week later, a regular DVM was performed. The amplitude of this migration gradually decreased towards the end of the migration period. The ascent in the evening and the descent in the morning took place after sunset and before sunrise, respectively. The movements coincided with high relative changes in light intensity. Population size increased rapidly during the period of DVM but decreased again before the end of this period.     

The lifetime of molecular (Davydov) solitons

The lifetime of Davydov solitons in a one-dimensional system is studied theoretically. The process of thermalization and the properties of solitons at finite temperature are investigated and the processes of soliton creation and disintegration are discussed.     

Colonization and extinction of land planarians (Platyhelminthes,Tricladida) in a Brazilian Atlantic Forest regrowth remnant

Long-term assessments of species assemblages are valuable tools for detecting species ecological preferences and their dispersal tracks, as well as for assessing the possible effects of alien species on native communities. Here we report a 50-year-long study on population dynamics of the four species of land flatworms (Platyhelminthes, Tricladida, Terricola) that have colonized or become extinct in a 70-year-old Atlantic Forest regrowth remnant through the period 1955–2006. On the one hand, the two initially most abundant species, which are native to the study site, Notogynaphallia ernesti and Geoplana multicolor have declined over decades and at present do not exist in the forest remnant. The extinction of these species is most likely related with their preference for open vegetation areas, which presently do not exist in the forest remnant. On the other hand, the neotropical Geoplaninae 1 and the exotic Endeavouria septemlineata were detected in the forest only very recently. The long-term study allowed us to conclude that Geoplaninae 1 was introduced into the study area, although it is only known from the study site. Endeavouria septemlineata, an active predator of the exotic giant African snail, is originally known from Hawaii. This land flatworm species was observed repeatedly in Brazilian anthropogenic areas, and this is the first report of the species in relatively well preserved native forest, which may be evidence of an ongoing adaptive process. Monitoring of its geographic spread and its ecological role would be a good practice for preventing potential damaging effects, since it also feeds on native mollusk fauna, as we observed in lab conditions. Júlio Pedroni: Granted by CNPQ–Brazil.     

Methodologies for the isolation of alternative binders with improved clinical potentiality over conventional antibodies

The availability of binders to different functional domains of the same protein or to physiologically co-operating proteins allows for the simultaneous inhibition of independent downstream signaling pathways. This multi-target approach represents a promising therapeutic strategy, as demonstrated in the case of the synergistic effect of anti-Her2 treatment based on the combined use of the trastuzumab and pertuzumab monoclonal antibodies that induce cellular cytotoxicity and impair the receptor dimerization, respectively. Therefore, a reliable selection method for the recovery of epitope-specific antibodies is highly needed. Animal immunization with short peptides resembling the epitope sequence for raising conventional antibodies represents an alternative. Panning phage displayed libraries of recombinant antibodies such as scFvs and nanobodies or of other peptide collections is another option. Although recombinant antibodies can provide the same specificity as conventional antibodies, they offer at least two further advantages: i) the protocols for the selection of epitope-specific antibodies can be rationally designed, and ii) their expression as multivalent, bispecific and biparatopic molecules is feasible. This review will analyze the recent literature concerning technical aspects related to the isolation, the expression as multivalent molecules, and the therapeutic applications of binders able to interfere with antigen functional domains. The term binder will be preferred when possible to include those molecules, such as peptides or affibodies, with at least some proven practical uses.     

Modelling HIV immune response and validation with clinical data

A system of ordinary differential equations is formulated to describe the pathogenesis of HIV infection, wherein certain features that have been shown to be important by recent experimental research are incorporated in the model. These include the role of CD4+memory cells that serve as a major reservoir of latently infected cells, a critical role for T-helper cells in the generation of CD8 memory cells capable of efficient recall response, and stimulation by antigens other than HIV. A stability analysis illustrates the capability of this model in admitting multiple locally asymptotically stable (locally a.s.) off-treatment equilibria. We show that this more biologically detailed model can exhibit the phenomenon of transient viremia experienced by some patients on therapy with viral load levels suppressed below the detection limit. We also show that the loss of CD4+T-cell help in the generation of CD8+memory cells leads to larger peak values for the viral load during transient viremia. Censored clinical data is used to obtain parameter estimates. We demonstrate that using a reduced set of 16 free parameters, obtained by fixing some parameters at their population averages, the model provides reasonable fits to the patient data and, moreover, that it exhibits good predictive capability. We further show that parameter values obtained for most clinical patients do not admit multiple locally a.s off-treatment equilibria. This suggests that treatment to move from a high viral load equilibrium state to an equilibrium state with a lower (or zero) viral load is not possible for these patients.     

Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally induced temperature influences on embryo development rate

Intrinsic processes are assumed to underlie life history expression and trade‐offs, but extrinsic inputs are theorised to shift trait expression and mask trade‐offs within species. Here, we explore application of this theory across species. We do this based on parentally induced embryo temperature as an extrinsic input, and mass‐specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected interspecific trade‐off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade‐offs across species.     

A neutron activation technique for manganese measurements in humans

Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Studies show that Mn metabolism is similar to that of iron, therefore, increased Mn levels in humans could interfere with the absorption of dietary iron leading to anemia. Also, excess exposure to Mn dust, leads to nervous system disorders similar to Parkinson's disease. Higher exposure to Mn is essentially related to industrial pollution. Thus, there is a benefit in developing a clean non-invasive technique for monitoring such increased levels of Mn in order to understand the risk of disease and development of appropriate treatments.To this end, the feasibility of Mn measurements with their minimum detection limits (MDL) has been reported earlier from the McMaster group. This work presents improvement to Mn assessment using an upgraded system and optimized times of irradiation and counting for induced gamma activity of Mn. The technique utilizes the high proton current Tandetron accelerator producing neutrons via the ⁷Li(p,n)⁷Be reaction at McMaster University and an array of nine NaI (Tl) detectors in a 4π geometry for delayed counting of gamma rays. The neutron irradiation of a set of phantoms was performed with protocols having different proton energy, current and time of irradiation. The improved MDLs estimated using the upgraded set up and constrained timings are reported as 0.67 μgMn/gCa for 2.3 MeV protons and 0.71 μgMn/gCa for 2.0 MeV protons. These are a factor of about 2.3 times better than previous measurements done at McMaster University using the in vivo set-up. Also, because of lower dose-equivalent and a relatively close MDL, the combination of: 2.0 MeV; 300 μA; 3 min protocol is recommended as compared to 2.3 MeV; 400 μA; 45 s protocol for further measurements of Mn in vivo.