Wenyonella baghdadensis sp. n. from the Bandicoot Rat Nesokia indica in the Baghdad Area

SYNOPSIS. Oocysts of Wenyonella baghdadensis sp. n. were found in the feces of 2 of 12 bandicoot rats Nesokia indica Gray & Hardwicke from the Baghdad area. Sporulated oocysts were subspherical to broadly ellipsoidal, 25.4 (18–22) × 20.8 (15–28) μm, with a 2-layered wall, the outer wall being mammillated, without micropyle, micropylar cap, residuum, or polar granule. Sporozoites were ovoid, 11.8 (9–15) × 8.4 (6–10) μm, with Stieda body and residuum. Two sporozoites in each sporocyst were elongate, with granular cytoplasm and a refractile globule, the other 2 were bean-shaped, without granules or refractile globule. Sporulation time equalled 3 days at 22–24 C. Entamoeba coli and Giardia sp. cysts were also found in 3 rats each.     

Eimeria taterae sp. n. and other Intestinal Parasites from the Antelope Rat, Tatera indica in Baghdad District

SYNOPSIS. Of 8 fecal specimens from the antelope rat, Tatera indica Hardwicke examined, 4 were found positive for intestinal parasites. Among these was Eimeria taterae sp. n., sporulated oocysts of which are described, their characteristics serving for the diagnosis of this species. Entamoeba coli cysts, as well as ova of Hymenolepis sp. and Trichuris sp., were also found.     

The evolution of sex pheromones in an ecologically diverse genus of flies

In theory, pheromones important in specific mate recognition should evolve via large shifts in composition (saltational changes) at speciation events. However, where other mechanisms exist to ensure reproductive isolation, no such selection for rapid divergence is expected. In Bactrocera fruit flies (Diptera: Tephritidae), males produce volatile chemicals to attract females for mating. Bactrocera species exhibit great ecological diversity, with a wide range of geographical locations and host plants used. They also have other mechanisms, including temporal and behavioural differences, which ensure reproductive isolation. Therefore, we predicted that their sex pheromones would not exhibit rapid divergence at speciation events. In the present study, we tested this idea by combining data on male sex pheromone composition for 19 species of Bactrocera with a phylogeny constructed from DNA sequence data. Analyses of the combined data revealed positive correlations between pheromone differences and nucleotide divergence between species, and between the number of pheromone changes along the phylogeny and the branch lengths associated with these changes. These results suggest a gradual rather than saltational mode of evolution. However, remarkable differences in sex pheromones composition exist, even between closely-related species. It appears therefore that the mode of evolution of sex pheromones in Bactrocera is best described by rapid saltational changes associated with speciation, followed by gradual divergence thereafter. Furthermore, species that do not overlap ecologically are just as different pheromonally as species that do. Thus, large changes in pheromone composition appear to be achieved, even in cases where other mechanisms to ensure reproductive isolation exist. We suggest that these differences are closely associated with rapid changes in host plant use, which is a characteristic feature of Bactrocera speciation. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97 , 594–603.     

Mesenchymal stem cell–derived extracellular vesicles: a new impetus of promoting angiogenesis in tissue regeneration

Over the past few decades, extracellular vesicles (EVs) have emerged as crucial mediators of intercellular communication. EVs encapsulate and convey information to surrounding cells or distant cells, where they mediate cellular biological responses. Among their multifaceted roles in the modulation of biological responses, the involvement of EVs in vascular development, growth and maturation has been widely documented and their potential therapeutic application in regenerative medicine or in the treatment of angiogenesis-related diseases is drawing increasing interest. In this review, we have summarized the details about the current knowledge on biogenesis of EVs and conventional isolation methods. Evidence supporting the use of EVs derived from mesenchymal stromal cells (MSCs) to enhance angiogenesis in the development of insufficient angiogenesis, such as chronic wounds, stroke and myocardial infarction, will also be discussed critically. Finally, the main challenges and prerequisites for their therapeutic applications will be evaluated.     

Camouflage and colour change: antipredator responses to bird and snake predators across multiple populations in a dwarf chameleon

Potential prey are often exposed to multiple predators that vary in their foraging tactics and ability to detect prey. For animals that rely on crypsis to avoid predators, one solution is to alter their behaviour or appearance to maximize crypsis in ways that are specific to different types of predator. We tested whether dwarf chameleons ( Bradypodion transvaalense ) showed different behavioural responses, including colour change, towards multiple predators (bird and snake models) that detect and capture prey in different ways, and whether these antipredator responses varied geographically. Chameleons consistently used the same body postures (lateral compression and flipping to the opposite side of the branch) and displayed similar chromatic (colour) contrast against the natural background in response to both predator types. However, they became significantly more achromatically contrasting (brighter) in the presence of the snake compared to the bird. This relative difference in achromatic contrast towards the two types of predator was consistent among populations. There were also significant differences in both absolute achromatic and chromatic contrast among populations despite very similar light environment, background coloration and habitat structure. Our results highlight facultative crypsis as one type of flexible antipredator tactic and emphasize the importance of visual ecology in understanding prey–predator interactions.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 437–446.     

Variable responses of skinks to a common history of rainforest fluctuation: concordance between phylogeography and palaeo-distribution models

There is a growing appreciation of impacts of late-Quaternary climate fluctuations on spatial patterns of species and genetic diversity. A major challenge is to understand how and why species respond individualistically to a common history of climate-induced habitat fluctuation. Here, we combine modelling of palaeo-distributions and mitochondrial-DNA phylogeographies to compare spatial patterns of population persistence and isolation across three species of rainforest skinks ( Saproscincus spp.) with varying climatic preferences. Using Akaike Information Criterion model-averaged projections, all three species are predicted to have maintained one or more small populations in the northern Wet Tropics, multiple or larger populations in the central region, and few if any in the south. For the high-elevation species, Saproscincus czechurai , the warm–wet climate of the mid Holocene was most restrictive, whereas for the generalist S. basiliscus and lower-elevation S. tetradactyla, the cool–dry last glacial maximum was most restrictive. As expected, S. czechurai was the most genetically structured species, although relative to modelled distributions, S. basiliscus had surprisingly deep phylogeographical structure among southern rainforest isolates, implying long-term isolation and persistence. For both S. basiliscus and S. tetradactyla, there was high genetic diversity and complex phylogeographical patterns in the central Wet Tropics, reflecting persistence of large, structured populations. A previously identified vicariant barrier separating northern and central regions is supported, and results from these species also emphasize a historical persistence of populations south of another biogeographical break, the Tully Gorge. Overall, the results support the contention that in a topographically heterogeneous landscape, species with broader climatic niches may maintain higher and more structured genetic diversity due to persistence through varying climates.