Pigeons and other birds as a reservoir for Cryptococcus spp

In the last 25 years, the cases of human and animal cryptococcosis have increased significantly. This is mostly due to the improvement in the survival of immunocompromised patients. The disease is frequently related to the exposure of this type of patients to avian droppings. Among birds, pigeon, Columba livia, is undoubtedly the most important reservoir for the Cryptococcus species. Nevertheless, the study of a large number of bird's species demonstrated that pigeons are not the only Cryptococcus spp. carriers. The suspicion of the birds being the source for the infection is now becoming a demonstrable fact thanks to the use of molecular typing methods. These methods allow the comparison between strains from birds to patients living around them, with high level of discrimination.     

Pineapple stem-derived bromelain based priming improves pepper seed protein reserve mobilization,germination, emergence and plant growth

Pepper seeds are slow to germinate and emergence is often non-uniform and incomplete, reducing gains from this cash crop. This study investigated the effects of pineapple stem- derived protease (stem bromelain) based priming on pepper seed germination in relation to reserve mobilization (specifically, proteins and amino acids), germination, emergence and plant growth. These parameters were compared across two controls, (1) unsoaked seeds and (2) seeds soaked in deionized water, and seeds soaked in pineapple stem bromelain crude extract (treatment). Seeds were soaked in bromelain crude extract possessing a proteolytic activity of 6.25 tU or deionized water (first control) for 3 h at 35 °C. Light microscopy revealed an abundance of protein bodies in the endosperm of the seeds prior to imbibition. When observed for a period of 96 h, these bodies were progressively degraded, with the rate of this degradation being fastest in bromelain-treated seeds. Quantitative analysis of protein levels confirmed this observation: 17.2 mg proteins/g FW at 120 h after priming in bromelain-treated seeds compared with 22.1 mg/g FW in controls (average). The bromelain treatment also increased levels of free amino acids from 3.9 mg/g FW in the controls to 4.6 mg/g FW after 120 h of imbibition. Germination and emergence percentages were initially higher in bromelain-treated seeds: 92.0% germination in bromelain-treated seeds vs. ~ 52.2% in the controls at 18 d; 100% emergence in protease-treated seeds vs. ~ 72.2% in the controls at 18 d. However, these parameters were comparable across the treatment and the controls at 28 d. Importantly, plant fresh and dry weights were significantly higher when seeds were primed with bromelain. The results suggest the use of bromelain extracts for priming pepper seeds based on their proteolytic activity, since germination is dependent on the availability of crude protein and essential amino acids. The benefits of bromelain seed priming appear to translate into improved seedling growth as well.     

Comparative spatial ecology of fished spiny lobsters <Emphasis Type="Italic">Panulirus argus</Emphasis> and an unfished congener <Emphasis Type="Italic">P. guttatus</Emphasis> in an isolated marine reserve at Glover's Reef atoll,Belize

Palinurid lobsters are being exploited with increasing intensity in coral reef ecosystems, but marine protected areas may play a key role in preventing overfishing and local extinctions. In order to define the spatial requirements for protection, we compared the spatial and temporal patterns in distribution, density, biomass, size structure, and reproductive seasonality of Caribbean spiny lobsters Panulirus argus and the congeneric spotted lobsters P. guttatus on coral patch reef, forereef, and deep reef habitat at Glover's Reef, Belize. The relative impact of fishing on P. argus was also examined in an isolated marine reserve and adjacent fished habitats, in comparison with the relatively unfished distribution of P. guttatus. Over a 5-year period, both species co-occurred in all major reef habitats, but aspects of their population dynamics differed markedly due to both habitat and fishing effects. All size classes of spiny lobsters P. argus occupied shallow patch reefs, but large adults were predominant on the deep wall reef. Panulirus guttatus also occupied patch reefs in the lagoon, but spur-and-groove forereef appeared to be the primary habitat of this species. Density and exploitable (adult) biomass of P. argus increased significantly over time in the protected patch reef habitat of the lagoon but remained stable on deep reef habitat. The biomass of spotted lobsters P. guttatus in all habitats was at least an order of magnitude less than that of exploitable P. argus. Reproductive activity by both species was evident most of the year in all habitats, but breeding P. argus females were concentrated on the deep reef. Commercial fisheries for spotted lobsters P. guttatus are currently being considered for development, but data from this and other studies suggest that such a fishery may be relatively unproductive and may lead to rapid localized extinctions. Spiny lobsters P. argus used a variety of coral reef habitats, but spotted lobsters P. guttatus were habitat specialists restricted to shallow reef habitat. The protection needs of both species are similar in one aspect: large protected areas. However, P. argus required large areas with heterogeneous habitats including coral reefs and seagrass beds, whereas P. guttatus required large areas of coral reef habitat.     

Comparison of biological and conventional insecticide treatments for the management of the pineapple fruit borer, Strymon megarus (Lepidoptera: Lycaenidae) in Costa Rica

Carbaryl is currently one of the most commonly used insecticides for the control of the pineapple fruit borer, Strymon megarus (Godart), in commercial pineapple production. To evaluate more sustainable biological alternatives to conventional insecticides, three microbial and one botanical insecticide were studied. Beauveria bassiana, Metarhizium anisopliae, Bacillus thuringiensis (Bt) and a plant extract from Quassia amara were compared with carbaryl in replicated field trials in Costa Rica during 2005 and 2006. In both years of testing, the untreated control received over 50% fruit damage from S. megarus. Bt and carbaryl provided the highest level of control and the lowest level of fruit damage compared to all other treatments. Based on the results of this study, Bt appears to be an acceptable biological alternative to the conventional insecticide (carbaryl) for control of S. megarus on pineapple. In addition, Bt was the least expensive treatment used in this study.     

Use of two gRNAs for CRISPR/Cas9 improves bi‐allelic homologous recombination efficiency in mouse embryonic stem cells

Targeted genome editing in mouse embryonic stem cells (ESCs) is a powerful resource to functionally characterize genes and regulatory elements. The use of the CRISPR/Cas9 genome editing approach has remarkably improved the time and efficiency of targeted recombination. However, the efficiency of this protocol is still far from ideal when aiming for bi‐allelic homologous recombination, requiring at least two independent targeting recombination events. Here we describe an improved protocol that uses two gRNAs flanking the selected targeted region, leading to highly efficient homologous recombination in mouse ESCs. The bi‐allelic recombination targeting efficiency is over 90% when using two gRNAs together with the inhibition of non‐homologous end‐joint repair. Moreover, this technique is compatible with the generation of knocked‐in mice and the use of ESC‐derived differentiation protocols, therefore facilitating and accelerating the gene targeting in mice and ESCs.     

Activation of the nitric oxide response in gilthead seabream after experimental infection with Photobacterium damselae subsp. piscicida

Inoculation of small gilthead seabream (Sparus aurata) (30-75 g body weight) with a sublethal dose of different Photobacterium damselae subsp. piscicida (Pdp) strains (DI-21 and 94/99) induced an increase in serum concentrations of stable nitric oxide (NO) metabolites lasting from 6 h to six days post-infection, with a peak at 24 h. In contrast, no such response was detected in larger fish (150-600 g). Since the virulence of Pdp correlates with the presence of a polysaccharide capsular layer which can be induced by growing the bacteria in medium supplemented with 1% glucose (C+ forms), the effect of the presence of an enhanced capsular layer on the NO response in small fish was also evaluated. Although, all bacteria induced a similar rapid (6 h) and sustained (up to six days) NO response, serum concentrations of nitrites and citrulline were significantly increased in fish infected with the Pdp strains grown in glucose-supplemented medium. When the NO response of fish infected with the C+ form of Pdp was blocked by prior injection of the inhibitor L-NAME, the LD(50) was reduced by over 10-fold and the mean time to death was also markedly reduced. Considering that (i) pasteurellosis only affects gilthead seabream with body weights below 100 g; (ii) capsulated Pdp are more resistant to the bactericidal action of NO and peroxynitrites than non-capsulated strains; and (iii) blocking the NO response of the fish results in greater susceptibility to Pdp, it seems reasonable to propose that the sustained NO response reported in this study represents a relevant protective mechanism of juvenile gilthead seabream against pasteurellosis.