Beauveria Bassiana Pathogenicity to the Citrus Rust Mite Phyllocoptruta Oleivora

The pathogenicity of Beauveria bassiana to one of the major pests of citrus crops, Phyllocoptruta oleivora, was assessed by inoculating mites with different concentrations of conidia (1×10⁶, 5×10⁶, 1×10⁷, 5×10⁷ and 1×10⁸). Treated mites were kept at controlled conditions (25 ± 0.5°C, 12 h photoperiod and 98% relative humidity) and mite survivorship was evaluated daily. Mortality was found to increase in time and was dependent on the conidia concentration, with values ranging from 24 to 91% for the lowest and highest conidia concentration, respectively. The calculated LC₅₀ on the fifth day was 4.23×10⁶ conidia/ml. Mean lethal time was 3.98, 9.79, 3.09 and 2.74 days for 5×10⁶, 1×10⁷, 5×10⁷ and 1×10⁸ conidia/ml, respectively. Conidia were found to adhere all over the mite body surface, especially at the anal region, where vegetative mycelium was found entering the mite body. We noticed the formation of small crystals inside the mite’s body that were produced during colonization of the body cavity by the fungus. This is the first report of B. bassiana pathogenicity for this species.     

Mediterranean Diplodus annularis (Teleostei: Sparidae) and its brain parasite: unforeseen outcome

Patterns of parasite load and aggregation of the bird trematode Cardiocephaloides longicollis in its main intermediate host in the Mediterranean, the annular sea bream, Diplodus annularis, were studied in a large sample collected off Valencia (Spain) and are discussed within the context of the parasite induced host mortality hypothesis. The metacercariae were located within large composite cysts of host origin in the ventricles of the optic lobes of the cerebrum. A weak immunological response was detected in older fish, which was significantly associated with the total parasite load. Although the mean abundance of C. longicollis showed a tendency to increase with host size, the infection levels were generally homogeneous with a noticeable plateauing in the intermediate size classes. The distribution of the metacercariae was aggregated and agreed with the negative binomial distribution. There was a marked decline in parasite aggregation in the largest size-class, suggesting parasite-induced host mortality in the oldest fish possibly due to predation by large non-host fish predators. On the other hand, levelling off of abundance and decrease in heterogeneity of parasite distribution within the intermediate age cohort could indicate that these sizes are being rapidly and/or constantly removed from the host population due to by-catch fishing. The overall high infection levels and the continuous recruitment across age cohorts provides evidence that an enhanced parasite transmission is taking place in the Gulf of Valencia due to increased spatial overlap of the hosts involved in the life cycle. We suggest a human-induced facilitation of the digenean life cycle due to the fact that gulls in the area feed extensively on discards, thus indicating the possibility of an unforeseen effect of fishing practices in a marine littoral system.     

ATP released via gap junction hemichannels from the pigment epithelium regulates neural retinal progenitor proliferation

The retinal pigment epithelium (RPE) plays an essential role in the normal development of the underlying neural retina, but the mechanisms by which this regulation occurs are largely unknown. Ca2+ transients, induced by the neurotransmitter ATP acting on purinergic receptors, both increase proliferation and stimulate DNA synthesis in neural retinal progenitor cells. Here, we show that the RPE regulates proliferation in the underlying neural retina by the release of a soluble factor and identify that factor as ATP. Further, we show that this ATP is released by efflux through gap junction connexin 43 hemichannels, the opening of which is evoked by spontaneous elevations of Ca2+ in trigger cells in the RPE. This release mechanism is localized within the RPE cells to the membranes facing the neural retina, a location ideally positioned to influence neural retinal development. ATP released from RPE hemichannels speeds both cell division and proliferation in the neural retina.     

Synthesis and binding affinity of novel 3-aminoethyl-1-tetralones, potential atypical antipsychotics

A series of 3-aminoethyl-1-tetralones, conformationally constrained higher homologues of haloperidol (standard for typical antipsychotic profile), have been obtained by a four-step route from valerolactone. Their binding affinities at dopamine D(2) and serotonin 5-HT2A and 5-HT2C receptors were determined, showing in some cases an atypical antipsychotic profile.     

Middle and long distance athletics races viewed from the perspective of complexity

Middle and long distance athletics races behave as power-laws when time (or average speed) and distance are related, thus suggesting the presence of critical phenomena. Power-laws as a function of the athlete's position in the all-time world ranking allows us to define a Performance Index that reveals the existence of possible multifractal structures associated to the natural barriers to that the athletes tend in their evolution towards better results and in pursuit of world records. The new theories of self-organized critical phenomena provide an explanation for the power-law and fractal structures in systems at, or near, their critical points. In this paper we analyse the athletic races using these theories and as a result of this study a new variety of interpretations are posited.     

Genetic damage following introduction of DNA in Phycomyces

Introduction of plasmids in Phycomyces blakesleeanus caused extensive changes in the exogenous DNA and in the resident genome. Plasmids with a bacterial gene for geneticin resistance under a Phycomyces promoter were either injected into immature sporangia or incubated with spheroplasts. An improved method produced about one viable spheroplast per cell. Colonies resistant to geneticin were rare and only about 0.1% of their spores grew in the presence of geneticin. The transformation frequency was very low, < or =1 transformed colony per million spheroplasts or per microg DNA. Few nuclei in the transformants contained exogenous DNA, as shown by a selective procedure that sampled single nuclei from heterokaryons. The exogenous DNA was not integrated into the genome and no stable transformants were obtained. The plasmids were replicated in the recipient cells, but their DNA sequences were modified by deletions and rearrangements and the transformed phenotype was eventually lost. The spores developed in injected sporangia were often inviable; a genetic test showed that spore death was caused by impaired nuclear proliferation and induction of lethal mutations. About one-fourth of the viable spores from injected sporangia formed abnormal colonies with obvious changes in shape, texture, or color. The abnormalities that could be investigated were due to dominant mutations. The results indicate that incoming DNA is not only attacked, but signals a situation of stress that leads to increased mutation and nuclear and cellular death.     

Phases dispersion and oxygen transfer in a simulated fermentation broth containing castor oil and proteins

The sizes of air bubbles and castor oil drops were studied by image analysis as a function of the concentration of soluble protein (bovine serum albumin [BSA] and lipase, as model proteins) in a three-phase system using a simulated fermentation medium (aqueous salt solution, castor oil, and air). Small amounts of proteins (<0.02 g/L) caused an important decrease in oil drops and bubbles sizes, together with a pronounced decrease in surface tension. The extent and profiles of this decrease seem to be determined by the conformation of the protein at the interface. The kLa value increased considerably for increasing concentration (up to 0.02 g/L) of the two proteins but was very different (2-fold higher for the lipase) at the highest concentrations tested (0.5 g/L), a phenomenon that can be caused by the extent to which bubbles are trapped within oil drops.