Aspects of reproduction and their implications for the conservation of the endangered limpet,Patella ferruginea

Summary

The protandric limpet, Patella ferruginea G., is the most endangered marine species in the Western Mediterranean and is at serious risk of extinction. Nevertheless, its biology and ecology are little known. In the present work, several reproductive aspects are studied. Recruitment take place in June and the largest individuals are the most scarce. The sex ratio is slanted towards the largest sizes, and the species seems to show sex change at sizes from 60 mm upwards, although males can be observed up to 80 mm. There is no correlation between size of oocytes and shell length; however, the larger females contribute greatly to the reproductive event, with high fecundity and GSI values. The mean diameter of oocytes was observed to be 149.78 μm, whereas the heads of spermatozoa were 3.78 μm long. The results of the present study increase the maximum length for males by double that cited in previous literature and highlight the importance of strictly protecting females (i.e., most of the largest individuals, >60 mm), since their population percentage is very low, in order to develop adequate strategies to preserve the species.     

Energy storage during the transition from endogenous to exogenous feeding in Australian redclaw crayfish Cherax quadricarinatus (Von Martens, 1898)

Summary

The Australian redclaw crayfish Cherax quadricarinatus hatches at an advanced stage. Two post-hatching stages rely on yolk reserves before the organism becomes a juvenile. After a juvenile appears, the yolk is depleted and young crayfish might spend a few days among female pleopods before starting to feed independently. During this phase, the juvenile organism needs alternative energy sources. Offspring from three females were analyzed with histological and histochemical techniques, from hatching until reaching the 2-week juvenile stage, to trace digestive system development and internal organ lipid and glycogen accumulation. Neutral lipids are stored in specialized cells of the hepatopancreatic tissue until the juvenile stage is reached. An increasing rate of accumulation was found. Glycogen was stored in hepatopancreas and tail muscle cells until post-embryo II, and no increasing or decreasing rate was found in storage functions.     

The K+/H+ antiporter LeNHX2 increases salt tolerance by improving K+ homeostasis in transgenic tomato

The endosomal LeNHX2 ion transporter exchanges H⁺ with K⁺ and, to lesser extent, Na⁺. Here, we investigated the response to NaCl supply and K⁺ deprivation in transgenic tomato (Solanum lycopersicum L.) overexpressing LeNHX2 and show that transformed tomato plants grew better in saline conditions than untransformed controls, whereas in the absence of K⁺ the opposite was found. Analysis of mineral composition showed a higher K⁺ content in roots, shoots and xylem sap of transgenic plants and no differences in Na⁺ content between transgenic and untransformed plants grown either in the presence or the absence of 120 mm NaCl. Transgenic plants showed higher Na⁺/H⁺ and, above all, K⁺/H⁺ transport activity in root intracellular membrane vesicles. Under K⁺ limiting conditions, transgenic plants enhanced root expression of the high‐affinity K⁺ uptake system HAK5 compared to untransformed controls. Furthermore, tomato overexpressing LeNHX2 showed twofold higher K⁺ depletion rates and half cytosolic K⁺ activity than untransformed controls. Under NaCl stress, transgenic plants showed higher uptake velocity for K⁺ and lower cytosolic K⁺ activity than untransformed plants. These results indicate the fundamental role of K⁺ homeostasis in the better performance of LeNHX2 overexpressing tomato under NaCl stress.     

Levels of IL-17F and IL-33 correlate with HLA-DR activation in clinical-grade human bone marrow–derived multipotent mesenchymal stromal cell expansion cultures

Background aims

Multipotent mesenchymal stromal cell (MSC)-based medicines are extensively investigated for use in regenerative medicine and immunotherapy applications. The International Society for Cell and Gene Therapy (ISCT) proposed a panel of cell surface molecules for MSC identification that includes human leukocyte antigen (HLA)-DR as a negative marker. However, its expression is largely unpredictable despite production under tightly controlled conditions and compliance with current Good Manufacturing Practices. Herein, we report the frequency of HLA-DR expression in 81 batches of clinical grade bone marrow (BM)-derived MSCs and investigated its impact on cell attributes and culture environment.

Plant patch structure modifies parasitoid assemblage richness of a specialist herbivore

1. The spatial structure of plant patches has been shown to affect host–parasitoid interactions, but its influence on parasitoid diversity remains largely ignored. Here we tested the prediction that parasitoid species richness of the specialist leafminer Liriomyza commelinae increases in larger and less isolated patches of its host plant Commelina erecta. We also explored whether parasitoid abundance and body size affected the occurrence of parasitoid species in local assemblages. 2. A total of 893 naturally established C. erecta patches were sampled on 18 sites around Córdoba city (Argentina). Also, two experiments were performed by creating patches differing in the number of plants and the distance from a parasitoid source. For these tests, plants were infected with the miner in the laboratory prior to placement in the field. 3. Plant patch size, independently of host abundance, positively affected the number of parasitoid species in both survey observations and experimental data. However, plant patch isolation did not influence parasitoid species richness. 4. The probability of finding rare parasitoid species increased with patch size, whereas occupation of isolated patches was independent of dispersal abilities (body size) of parasitoid species. 5. Overall, the results highlight the importance of considering spatial aspects such as the size of plant patches in the study of parasitoid communities.     

Effects of livestock breed and grazing pressure on ground‐dwelling arthropods in Cantabrian heathlands

Abstract 1. The effects of different goat breeds and grazing pressures on epigeal arachnids (Lycosidae and Opiliones) and ground beetles (Carabidae) were assessed in a heath–gorse shrubland located in the north of the Iberian Peninsula. Three treatments (low grazing pressure with Cashmere breed, high grazing pressure with Cashmere breed, and high grazing pressure with local Celtiberic breed) with three replicates of each treatment were allocated randomly to nine plots. 2. Arthropod fauna abundance, diversity, and species richness were estimated using pitfall trapping over 3 years (2003, 2004, and 2005). Vegetation cover, composition, and height were assessed along transects and above‐ground plant biomass was sampled in quadrats. 3. Lower grazing pressure led to lower herbaceous cover and higher heather cover than high grazing pressure. Overall, it did not enhance arthropod diversity or abundance, but the abundance and species richness of carabids, and abundance of lycosids like Pardosa pullata, were higher under high stocking rates, whereas Opiliones were favoured by the low stocking rates. Although it has been assumed that traditional breeds enhance biodiversity, the present study found no significant differences for both arthropod fauna and vegetation between the goat breeds. 4. Arthropod–vegetation relationships were examined by constrained ordination. Fauna assemblages followed a gradient from closed canopy shrubland areas, in the lowest grazing pressure, to grassier open canopy areas resulting from higher grazing pressure, revealing the importance of grazing management as a driver of arthropod community structure of the heathland.     

Ozone‐induced reductions in below‐ground biomass: an anatomical approach in potato

Potato plants were grown in open‐top chambers under three ozone concentrations during two complete cropping seasons (93 and 77 d in 2004 and 2005, respectively). The effects of chronic exposure to ozone on leaf anatomy, cell ultrastructure and crop yield were studied. Severe cell damage was found, even at ambient ozone levels, mainly affecting the spongy parenchyma and areas near the stomata. Damage to the cell wall caused loss of cell contact, and loss of turgor pressure due to tonoplast disintegration, contributed to cell collapse. Phloem sieve plates were obstructed by callose accumulation, and damaged mesophyll cells increased their starch stores. Tuber yield fell sharply (24–44%), due to the biggest tubers becoming smaller, which affected commercial yield. These anatomical findings show the mechanisms of ozone effect on assimilate partitioning, and thus crop yield decrease, in potato. Further implications of ozone causing reductions in below‐ground biomass are also discussed.     

Disentangling the relative importance of climate,size and competition on tree growth in Iberian forests: implications for forest management under global change

Most large‐scale multispecies studies of tree growth have been conducted in tropical and cool temperate forests, whereas Mediterranean water‐limited ecosystems have received much less attention. This limits our understanding of how growth of coexisting tree species varies along environmental gradients in these forests, and the implications for species interactions and community assembly under current and future climatic conditions. Here, we quantify the absolute effect and relative importance of climate, tree size and competition as determinants of tree growth patterns in Iberian forests, and explore interspecific differences in the two components of competitive ability (competitive response and effect) along climatic and size gradients. Spatially explicit neighborhood models were developed to predict tree growth for the 15 most abundant Iberian tree species using permanent‐plot data from the Spanish Second and Third National Forest Inventory (IFN). Our neighborhood analyses showed a climatic and size effect on tree growth, but also revealed that competition from neighbors has a comparatively much larger impact on growth in Iberian forests. Moreover, the sensitivity to competition (i.e. competitive response) of target trees varied markedly along climatic gradients causing significant rank reversals in species performance, particularly under xeric conditions. We also found compelling evidence for strong species‐specific competitive effects in these forests. Altogether, these results constitute critical new information which not only furthers our understanding of important theoretical questions about the assembly of Mediterranean forests, but will also be of help in developing new guidelines for adapting forests in this climatic boundary to global change. If we consider the climatic gradients of this study as a surrogate for future climatic conditions, then we should expect absolute growth rates to decrease and sensitivity to competition to increase in most forests of the Iberian Peninsula (in all but the northern Atlantic forests), making these management considerations even more important in the future.     

Detection and identification of Bartonella sp. in fleas from carnivorous mammals in Andalusia,Spain

A total of 559 fleas representing four species (Pulex irritans, Ctenocephalides felis, Ctenocephalides canis and Spilopsyllus cuniculi) collected on carnivores (five Iberian lynx Lynx pardinus, six European wildcat Felis silvestris, 10 common genet Genetta genetta, three Eurasian badger Meles meles, 22 red fox Vulpes vulpes, 87 dogs and 23 cats) in Andalusia, southern Spain, were distributed in 156 pools of monospecific flea from each carnivore, and tested for Bartonella infection in an assay based on polymerase chain reaction (PCR) amplification of the 16 S–23 S rRNA intergenic spacer region. Twenty‐one samples (13.5%) were positive and the sequence data showed the presence of four different Bartonella species. Bartonella henselae was detected in nine pools of Ctenocephalides felis from cats and dogs and in three pools of Ctenocephalides canis from cats; Bartonella clarridgeiae in Ctenocephalides felis from a cat, and Bartonella alsatica in Spilopsyllus cuniculi from a wildcat. DNA of Bartonella sp., closely related to Bartonella rochalimae, was found in seven pools of Pulex irritans from foxes. This is the first detection of B. alsatica and Bartonella sp. in the Iberian Peninsula. All of these Bartonella species have been implicated as agents of human diseases. The present survey confirms that carnivores are major reservoirs for Bartonella spp.