FENESTRATE BRYOZOAN GENERA BASED ON SPECIES FROM IRELAND ORIGINALLY DESCRIBED BY FREDERICK M'COY IN 1844

Abstract:  A large number of fenestrate bryozoan species were named in 'A Synopsis of the Characters of the Carboniferous Limestone Fossils of Ireland' by Frederick M'Coy (1844). At the same time, M'Coy named the bryozoan genera Ichthyorachis , Ptylopora and Polypora , each of which by monotypy or by subsequent designation was based on new species within that work. Subsequently, d' Orbigny (1849) named Fenestrellina with the type species Fenestella crassa M'Coy, 1844 as type species; Miller (1961) named Parafenestella with the type species Fenestella formosa M'Coy, 1844 as type species; and Wyse Jackson (1988) named Baculopora with the type species Vincularia megastoma M'Coy, 1844. We re-describe here in more detail than previously the fenestrate type species originally published in M'Coy (1844), provide diagnoses of the genera, and compare the nineteenth century genera with more recently named genera that have been discriminated specifically from them.     

Molecular systematics of mantelline frogs from Madagascar and the evolution of their femoral glands

Several genera of frogs from Madagascar, classified in the family Mantellidae, subfamily Mantellinae, possess structures commonly called 'femoral glands' on the ventral side of their shanks. The question arises as to the origin and phylogenetic significance of these glands. A molecular phylogeny based on 3601 nucleotide DNA sequences of three mitochondrial and two nuclear genes of 30 mantellid species provided strong support for monophyly of the included mantellines, all characterized by enlarged femoral gland clusters, as well as for those with gland clusters of coordinated central arrangement of secretion ducts. However, the phylogeny also strongly supported the hypothesis of convergent evolution of structurally similar glands in unrelated frogs ( Indirana , Petropedetes ), and several trends of convergent evolution of gland structure within mantellines. We studied the light microscopic structure of the femoral glands in a representative array of 18 mantellid species. Males of all species of the subfamily Mantellinae were characterized by clusters of distinct single glands. Each was structurally similar to an enlarged granular gland and secreted independently, probably through a single duct. By contrast, the largely semi-aquatic frogs in the genus Mantidactylus had a specialized cluster of glands, in which the secretion ducts led into a macroscopically recognizable central depression. In Boophis opisthodon , a mantellid species of the subfamily Boophinae without externally recognizable femoral glands, we observed a large number of enlarged granular glands of various sizes in the ventral skin of the shank. This observation is consistent with the hypothesis that the large and more uniform organs of mantellines are derived granular glands.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 529–539.     

MicroRNAs in cancer drug resistance: Basic evidence and clinical applications

Development of drug resistance has considerably limited the efficacy of cancer treatments, including chemotherapy and targeted therapies. Hence, understanding the molecular mechanisms underpinning the innate or the acquired resistance to these therapies is critical to improve drug efficiency and clinical outcomes. Several studies have implicated microRNAs (miRNA) in this process. MiRNAs repress gene expression by specific binding to complementary sequences in the 3' region of target messenger RNAs (mRNAs), followed by target mRNA degradation or blocked translation. By targeting molecules specific to a particular pathway within tumor cells, the new generation of cancer treatment strategies has shown significant advantages over conventional chemotherapy. However, the long-term efficacy of targeted therapies often remains poor, because tumor cells develop resistance to such therapeutics. Targeted therapies often involve monoclonal antibodies (mAbs), such as those blocking the ErB/HER tyrosine kinases, epidermal growth factor receptor (cetuximab) and HER2 (trastuzumab), and those inhibiting vascular endothelial growth factor receptor signaling (e.g., bevacizumab). Even though these are among the most used agents in tumor medicine, clinical response to these drugs is reduced due to the emergence of drug resistance as a result of toxic effects in the tumor microenvironment. Research on different types of human cancers has revealed that aberrant expression of miRNAs promotes resistance to the aforementioned drugs. In this study, we review the mechanisms of tumor cell resistance to mAb therapies and the role of miRNAs therein. Emerging treatment strategies combine therapies using innovative miRNA mimics or antagonizers with conventional approaches to maximize outcomes of patients with cancer.     

Are behavioural traits in prey sensitive to the risk imposed by predatory fish?

1. Behavioural differences among prey species may result from evolutionary adaptations that facilitate coexistence with different predators and influence vulnerability to predators. It has been hypothesised that prey species modify their behaviour in relation to the risk posed by particular predators. 2. We examined the relationship between anti‐predator behaviour and predation risk in five species of larval odonates in combination with three predatory fish species (perch, gudgeon and rudd) that differ in foraging behaviour. The odonates, Platycnemis pennipes, Coenagrion puella, Lestes sponsa, Sympetrum striolatum and Libellula depressa, differ with regard to their life cycle and habitat, including water depth, occurrence in temporary ponds and co‐existence with fish. 3. The odonate species differed in their response to fish: (i) Two species showed a flexible response. Larval C. puella reduced activity in the presence of fish, regardless of species, whereas L. depressa altered their activity only in the presence of gudgeon. (ii) Independent of fish species, all odonates except L. depressa exhibited spatial avoidance of fish. This was interpreted as a more general anti‐predator response. (iii) In some cases the odonates showed no response to predators and their behaviour was thus independent of predation risk. 4. Our results confirm that all odonates responded to the presence of at least some predatory fish, and that some odonate species discriminated between fish species. However, we found no significant correlation between behavioural modifications and predation risk, indicating that anti‐predator responses and predation risk depend on the particular predator and the species being preyed on.     

Sexual size dimorphism and sex ratios in dragonflies (Odonata)

Sexual size dimorphism and biased sex ratios are common in animals. Rensch's rule states that sexual size dimorphism (SSD) would increase with body size in taxa where males are larger than females and decrease with body size in taxa where females are larger. We tested this trend in dragonflies (Odonata) by analysing body size of 21 species and found support for Rensch's rule. The increase in SSD with increasing size among species can be explained by sexual selection favouring large males. We also estimated the slope of the relationship between sex ratio and size ratio in populations of the 21 species. A negative slope would suggest that the larger sex suffers from high mortality in the larval stage, consistent with riskier foraging. The slope of this relationship was negative, but after correcting for phylogentic non-independence with independent contrasts the relationship was no longer statistically significant, perhaps because of phylogenic inertia or low sample size.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 507–513.     

Model estimates of methane emission from irrigated rice cultivation of China

A model developed by the authors ( Huang et al. 1998 ) was further validated against field measurements from various regions of the world and calibrated to estimate methane emission from irrigated rice cultivation of China. On the basis of available information on rice cultivated area, growth duration, grain yield, soil texture and temperature, methane emission from Chinese rice paddies was estimated for 28 rice cultivated provinces in mainland. The calculated daily methane emission rates, on a provincial scale, ranged from 0.15 to 0.86 g m^–2 with an average of 0.32 g m^–2. Five of the top six locations with higher daily methane emissions are located at a latitude between 28° and 31° N. A total amount of 9.66 Tg (1 Tg = 10¹² g) CH₄ per year, ranging from 7.19 to 13.62, was estimated to be released from Chinese rice paddy soils. Of the total, 45% is emitted from the single-rice growing season, and 19% and 36% are from the early-rice and the late-rice growing seasons, respectively. Approximately 70% of the total is emitted in the region located at latitude between 25° and 32° N. The emissions from rice fields in Sichuan and Hunan Province were calculated to be 2.85 Tg y^–1, accounting for ≈ 30% of the total. Comparisons of the estimated and the observed emission rates show that the estimates were, in general, close to the measurements at most locations.     

EARLY HISTOGENESIS OF TRANSPLANTED MOUSE MAMMARY GLANDS III. PARENCHYMAL-STROMAL INTERACTIONS *

Mammary isografts dissociated in gland-free fat pads in 24 hr but regenerated single glands. Isografts in the anterior chamber of the eye did not dissociate but regenerated only after collagenase treatment and retransplantation to gland-free fat pads.     

Flow and polypide distribution in the cheilostome bryozoan Bugula and their inference in Archimedes

Cilia-generated flow in the absence of ambient current is directed from frontal to reverse sides of branches in Bugula turrita, B. turbinata, B. neritina , and B. stolonifera , whether axes of feeding lophophores are perpendicular to the basal plane of branches or are tilted toward distal ends of branches. Ambient current less than 5 cm per second interacts with cilia-generated flow, but ambient flow of 15 cm per second destroys self-generated colonial flow and severely hampers feeding. Polypides are located in the more distal, younger portions of colonies, in species with and without polypide recycling, whereas zooids in the more proximal, older portions are senesced. Presence of feeding polypides in distal but not in proximal portions of the larger spiralled colonies of B. turrita and B. turbinata results in downward, slightly radially directed flow through the colony. The colonial flow passes directly from one whorl to the next-proximal so that water exits from low around the colony perimeter, and a proximally expanding conical stagnant zone occupies the interior of the colony. A substantial percentage of zooecia in distal whorls of well-preserved Archimedes is filled by sediment and inferred to have been occupied by actively feeding polypides. whereas spar-filled zooecia capped by terminal diaphragms were apparently senesced during the latter part of a colony's existence. The capped zooecia constitute an increasing percentage of the total in more proximal whorls. Generally similar colony form and inferred similarity in distribution of current-generating polypides in spiralled colonies of Bugula and in Archimedes suggest that colony-generated flow in Archimedes was similar to that in Bugula , passing downward and then outward, and only through the distal whorls of the colonies.