Nasal administration of Lactococcus lactis improves local and systemic immune responses against Streptococcus pneumoniae

Lactococcus lactis NZ9000 is a non-pathogenic non-invasive bacterium extensively used for the delivery of antigens and cytokines at the mucosal level. However, there are no reports concerning the per se immunomodulatory capacity of this strain. The aim of the present study was to investigate the intrinsic immunostimulating properties of the nasal administration of L. lactis NZ9000 in a pneumococcal infection model. Mice were preventively treated with L. lactis (2, 5 or 7 days with 10(8) cells/day per mouse) and then challenged with Streptococcus pneumoniae. The local and the systemic immune responses were evaluated. Our results showed that nasal administration of L. lactis for 5 days (LLN5d) increased the clearance rate of S. pneumoniae from lung and prevented the dissemination of pneumococci into blood. This effect coincided with an upregulation of the innate and specific immune responses in both local and systemic compartments. LLN5d increased phagocyte activation in lung, blood and bone marrow, determined by NBT and peroxidase tests. Anti-pneumococcal immunoglobulin (Ig)A in bronchoalveolar lavages (BAL) and IgG in BAL and serum were increased in the LLN5d group. Lung tissue injury was reduced by LLN5d treatment as revealed by histopathological examination and albumin concentration and lactate dehydrogenase activity in BAL. The adjuvant effect of L. lactis in our infection model would be an important advantage for its use as a delivery vehicle of pneumococcal proteins and nasal immunization with recombinant L. lactis emerges as an effective route of vaccination for both systemic and mucosal immunity against pneumococcal infection.     

Factors that affect the re-attachment of Chondracanthus chamissoi (Rhodophyta, Gigartinales) thalli

Vegetative reproduction of Chondracanthus chamissoi by means of fragmentation and re-attachment of thalli is considered an effective strategy for maintaining natural populations of this species. Here, we evaluate the effects of (1) time of drifting thallus, (2) type of substratum, and (3) photon flux density, on the re-attachment capacity of thallus fragments of C. chamissoi. The results show that re-attachment decreases with the time after detachment, and was higher at the lower photon flux densities tested (10 and 40 μmol photons m⁻²s⁻¹), and on calcareous substratum. Secondary attachment discs are formed along the entire surface of the fragment.     

Synthesis and evaluation of quinazoline derivatives as phosphodiesterase 7 inhibitors

The latest scientific findings concerning PDE7 and PDE4 inhibition suggest that selective small-molecule inhibitors of both enzymes could provide a novel approach to treat a variety of immunological diseases. In this context, we describe a new series of quinazoline derivatives from quinazolin-4-thiones which include a substituted biphenyl fragment. Some of these compounds show inhibitory potencies at sub-micromolar levels against the catalytic domain of PDE7.     

Human-Induced Trophic Cascades along the Fecal Detritus Pathway

Human presence and activity in tropical forest is thought to exert top-down regulation over the various ‘green-world’ pathways of plant-based foodwebs. However, these effects have never been explored for the ‘brown-world’ pathways of fecal-detritus webs. The strong effects of humans on tropical game mammals are likely to indirectly influence fecal detritivores (including Scarabaeine dung beetles), with subsequent indirect impacts on detrivore-mediated and plant-facilitating detrital processes. Across a 380-km gradient of human influence in the western Brazilian Amazon, we conducted the first landscape-level assessment of human-induced cascade effects on the fecal detritus pathway, by coupling data on human impact, game mammal and detritivore community structure, and rate measurements of a key detritus process (i.e. dung beetle-mediated secondary seed dispersal). We found evidence that human impact indirectly influences both the diversity and biomass of fecal detritivores, but not detritivore-mediated processes. Cascade strength varied across detritivore groups defined by species'' traits. We found smaller-bodied dung beetles were at higher risk of local decline in areas of human presence, and that body size was a better predictor of cascade structure than fecal resource manipulation strategy. Cascade strength was also stronger in upland, unflooded forests, than in seasonally flooded forests. Our results suggest that the impact of human activity in tropical forest on fecal-detritus food web structure is mediated by both species'' traits and habitat type. Further research will be required to determine the conditions under which these cascade effects influence fecal-detritus web function.     

Bovine babesiosis: Cattle protected in the field with a frozen vaccine containing Babesia bovis and Babesia bigemina cultured in vitro with a serum-free medium

An attenuated live vaccine containing Babesia bovis and B. bigemina cultured in vitro with a serum-free medium was assessed for its clinical protection conferred of naïve cattle, under natural tick-challenge in a high endemicity zone to Babesia spp. Three groups of six animals were treated as follows: group I (GI) received a vaccine derived from parasites cultured with a free-serum medium; group II (GII) were immunized with the standard vaccine, with parasites cultured in a medium supplemented with 40% (v/v) bovine serum; and a control group (GIII) inoculated with non-infected bovine erythrocytes. Inocula were administered by IM route. Experimental animals were kept during 23 days after vaccination in a cattle farm free of ticks and Babesia spp. Thereafter, cattle were moved to a high endemicity farm for natural exposure to Babesia spp. transmitted by Rhipicephalus microplus ticks. Protection against clinical babesiosis was observed in bovines belonging to GI (100%) and GII (83.33%), while the control animals (GIII) were not protected, and showed severe clinical signs, closely related to babesiosis, were observed for at least three consecutive days during the challenge. These were fever, anemia, which were measured simultaneously, and circulating parasites were detected by optic light microscopy. All cattle showed B. bovis and B. bigemina in stained blood films during the challenge; B. bovis antibody titers were higher than those to B. bigemina in GI and GII, and lower titers were determined in GIII. The protective capacity of the vaccine derived from B. bovis and B. bigemina cultured in vitro in a serum-free medium was demonstrated.     

Are kelp holdfasts islands on the ocean floor? – indication for temporarily closed aggregations of peracarid crustaceans

During the colonisation process of islands, newly immigrating species often arrive as single individuals. Islands that have received single colonisers may subsequently harbour large populations of a species, while other islands may completely lack this species. Exchange between islands is limited, thereby strongly affecting evolutionary processes. While this concept is widely used in the context of oceanic islands or habitat patches on the mainland, it is rarely used to explain and examine the distribution patterns of marine invertebrates. Benthic marine organisms inhabiting patches with island-like features may also be restricted in their movements between patches. Once established in a patch, it may be more favourable to remain there rather than moving to another patch. Juveniles of species with direct development may recruit to the island patch of their parents. Herein, we examined the peracarid fauna in patches that have island-like features, i.e. kelp holdfasts. The number of peracarid species within an individual holdfast increased with its size. Similarly, the number of individuals per holdfast increased with holdfast size. However, several peracarid species showed a strongly aggregated distribution pattern, being highly abundant in some holdfasts and almost completely absent in others. Our results suggest that these aggregations of conspecifics may be a consequence of the peracarid reproductive biology: fully developed juveniles emerge from the female's marsupium and recruit to the immediate vicinity of their mother, showing little or no tendency to emigrate towards other patches. At present, while it is not known how long peracarid aggregations within kelp holdfasts persist, our data suggest that some juveniles may remain with the natal holdfast and possibly reproduce therein. It is concluded that, during certain time periods, reproduction rates of peracarids in a holdfast may exceed their migration rates between holdfasts.     

Resolving structure and mechanical properties at the nanoscale of viruses with frequency modulation atomic force microscopy

Structural Biology (SB) techniques are particularly successful in solving virus structures. Taking advantage of the symmetries, a heavy averaging on the data of a large number of specimens, results in an accurate determination of the structure of the sample. However, these techniques do not provide true single molecule information of viruses in physiological conditions. To answer many fundamental questions about the quickly expanding physical virology it is important to develop techniques with the capability to reach nanometer scale resolution on both structure and physical properties of individual molecules in physiological conditions. Atomic force microscopy (AFM) fulfills these requirements providing images of individual virus particles under physiological conditions, along with the characterization of a variety of properties including local adhesion and elasticity. Using conventional AFM modes is easy to obtain molecular resolved images on flat samples, such as the purple membrane, or large viruses as the Giant Mimivirus. On the contrary, small virus particles (25-50 nm) cannot be easily imaged. In this work we present Frequency Modulation atomic force microscopy (FM-AFM) working in physiological conditions as an accurate and powerful technique to study virus particles. Our interpretation of the so called "dissipation channel" in terms of mechanical properties allows us to provide maps where the local stiffness of the virus particles are resolved with nanometer resolution. FM-AFM can be considered as a non invasive technique since, as we demonstrate in our experiments, we are able to sense forces down to 20 pN. The methodology reported here is of general interest since it can be applied to a large number of biological samples. In particular, the importance of mechanical interactions is a hot topic in different aspects of biotechnology ranging from protein folding to stem cells differentiation where conventional AFM modes are already being used.     

Development and mapping of peach candidate genes involved in fruit quality and their transferability and potential use in other Rosaceae species

The goal of the present study was to identify candidate genes (CGs) involved in fruit quality in peach that can be transferred to other Rosaceae species. Two cDNA libraries from fruit of the “Fantasia” peach cultivar, constructed at two stages of development, were used to generate a set of expressed sequence tag sequences. A total of 1,730 peach unigenes were obtained after clustering. Sequences and corresponding annotations were stored in a relational database and are available through a web interface. Fifty-nine CGs involved in fruit growth and development or fruit quality at maturity, focusing on sweetness, acidity, and phenolic compound content, were selected according to their annotation. Fifty-five primer pairs, designed from peach CG sequences and giving PCR products in peach, were tested in strawberry and 36 gave amplified products. Eight CGs were mapped in peach, 14 in strawberry, four in both species and confirmed the pattern of synteny already proposed using comparative mapping. In peach, the CGs are located in three linkage groups (3, 5, 7), and in strawberry they are distributed in all seven Fragaria linkage groups. Colocalization between some of these CGs and quantitative trait loci for fruit quality traits were identified and are awaiting confirmation in further analyses.