Molecular phylogenetic studies reveal an undescribed species within the North American concept of Melanelixia glabra (Parmeliaceae)

We employ a molecular phylogenetic approach using nuclear ITS and mitochondrial SSU rDNA gene regions to test the general efficacy of species boundaries in the morphological species Melanelixia glabra. 35 new sequences are generated for this study. Our results provide evidence that M. glabra is polyphyletic, indicating that using only morphological criteria to define species boundaries in this group of lichenised fungi underestimates actual species-level diversity. These analyses also demonstrate that the geographically distant population of the M. glabra complex in North America is the sister group of two Indian species (M. glabroides and M. villosella) and exhibits considerable molecular divergence from the European and Turkish specimens (M. glabra s. str). Additionally, some minor morphological differences support the isolation of the American clade. Such results strongly suggest that this population of M. glabra is a new phylogenetic (morphological+phylogenetic) taxon that is described here as a new species (Melanelixia californica). Our approach using two independent genes appears to be a rigorous method to critically examine species boundaries originally based on traditional morphological approaches in this group of lichenised fungi. Our study shows that the use of morphology, molecular data and geography provide a robust approach to delimitation of phylogenetic species.     

Phylogenomic analysis of 2556 single-copy protein-coding genes resolves most evolutionary relationships for the major clades in the most diverse group of lichen-forming fungi

Phylogenomic datasets continue to enhance our understanding of evolutionary relationships in many lineages of organisms. However, genome-scale data have not been widely implemented in reconstructing relationships in lichenized fungi. Here we generate a data set comprised of 2556 single-copy protein-coding genes to reconstruct previously unresolved relationships in the most diverse family of lichen-forming fungi, Parmeliaceae. Our sampling included 51 taxa, mainly from the subfamily Parmelioideae, and represented six of the seven previously identified major clades within the family. Our results provided strong support for the monophyly of each of these major clades and most backbone relationships in the topology were recovered with high nodal support based on concatenated dataset and species tree analyses. The alectorioid clade was strongly supported as sister-group to all remaining clades, which were divided into two major sister-groups. In the first major clade the anzioid and usneoid clades formed a strongly supported sister-group relationship with the cetrarioid?+?hypogymnioid group. The sister-group relationship of Evernia with the cetrarioid clade was also strongly supported, whereas that between the anzioid and usneoid clades needs further investigation. In the second major clade Oropogon and Platismatia were sister to the parmelioid group, while the position of Omphalora was not fully resolved. This study demonstrates the power of genome-scale data sets to resolve long-standing, ambiguous phylogenetic relationships of lichen-forming fungi. Furthermore, the topology inferred in this study will provide a valuable framework for better understanding diversification in the most diverse lineage of lichen-forming fungi, Parmeliaceae.     

A multidimensional approach for detecting species patterns in Malagasy vertebrates

The biodiversity of Madagascar is extraordinarily distinctive, diverse, and endangered. It is therefore urgent that steps be taken to document, describe, interpret, and protect this exceptional biota. As a collaborative group of field and laboratory biologists, we employ a suite of methodological and analytical tools to investigate the vertebrate portion of Madagascar's fauna. Given that species are the fundamental unit of evolution, where micro- and macroevolutionary forces converge to generate biological diversity, a thorough understanding of species distribution and abundance is critical for understanding the evolutionary, ecological, and biogeographic forces that have shaped Malagasy vertebrate diversity. We illustrate the means by which we apply Mayr's "three basic tasks" of the systematist [Mayr, E. (1942) Systematics and the Origin of Species from the Viewpoint of a Zoologist (Harvard Univ. Press, Cambridge, MA)] to identify, classify, and study the organisms that together constitute Madagascar's vertebrate community. Using field inventory methods, specimen-based studies, and morphological and molecular analyses, we formulate hypotheses of species identity that then serve as the foundation for subsequent studies of biology and history. Our experience, as well as that of other investigators, has shown that much of the vertebrate species diversity in Madagascar is "cryptic" for both biological and practical reasons. Beyond issues of cryptic biological diversity, the resolution of species identity in Madagascar has been hampered because of a lack of vouchered comparative material at the population level. Through our activities, we are attempting to remedy these limitations while simultaneously enhancing research capacity in Madagascar.     

A randomised study comparing peripheral blood progenitor mobilisation using intermediate-dose cyclophosphamide plus lenograstim with lenograstim alone

We conducted a prospective randomised study to compare the efficiency of out-patient progenitor cell mobilisation using either intermediate-dose cyclophosphamide (2 g/m(2)) and lenograstim at 5 micrograms/kg (Cyclo-G-CSF group, n=39) or lenograstim alone at 10 micrograms/kg (G-CSF group, n=40). The end points were to compare the impact of the two regimens on mobilisation efficiency, morbidity, time spent in hospital, the number of apheresis procedures required and engraftment kinetics. Successful mobilisation was achieved in 28/40 (70%) in the G-CSF group vs 22/39 (56.4%) for Cyclo-G-CSF (P=0.21). The median number of CD34+ cells mobilised was 2.3 x 10(6)/kg and 2.2 x 10(6)/kg for G-CSF and cyclo-G-CSF arms following a median of two apheresis procedures. Nausea and vomiting and total time spent in the hospital during mobilisation were significantly greater after Cyclo-G-CSF (P<0.05). Rapid neutrophil and platelet engraftment was achieved in all transplanted patients in both groups. In conclusion, G-CSF at 10 micrograms/kg was as efficient at mobilising progenitor cells as a combination of cyclophosphamide and G-CSF with reduced hospitalisation and side effects and prompt engraftment. When aggressive in-patient cytoreductive regimens are not required to both control disease and generate progenitor cells, the use of G-CSF alone appears preferable to combination with intermediate-dose cyclophosphamide.     

From the Cover: Specialized insulin is used for chemical warfare by fish-hunting cone snails

More than 100 species of venomous cone snails (genus Conus) are highly effective predators of fish. The vast majority of venom components identified and functionally characterized to date are neurotoxins specifically targeted to receptors, ion channels, and transporters in the nervous system of prey, predators, or competitors. Here we describe a venom component targeting energy metabolism, a radically different mechanism. Two fish-hunting cone snails, Conus geographus and Conus tulipa, have evolved specialized insulins that are expressed as major components of their venoms. These insulins are distinctive in having much greater similarity to fish insulins than to the molluscan hormone and are unique in that posttranslational modifications characteristic of conotoxins (hydroxyproline, γ-carboxyglutamate) are present. When injected into fish, the venom insulin elicits hypoglycemic shock, a condition characterized by dangerously low blood glucose. Our evidence suggests that insulin is specifically used as a weapon for prey capture by a subset of fish-hunting cone snails that use a net strategy to capture prey. Insulin appears to be a component of the nirvana cabal, a toxin combination in these venoms that is released into the water to disorient schools of small fish, making them easier to engulf with the snail’s distended false mouth, which functions as a net. If an entire school of fish simultaneously experiences hypoglycemic shock, this should directly facilitate capture by the predatory snail.The venoms of predatory marine cone snails are remarkably potent and diverse (1). Most bioactive venom components are small disulfide-rich peptides, termed conotoxins (1), that target specific receptors and ion channel subtypes located in the prey’s nervous system (2, 3). Here, we provide evidence for a specialized insulin in the venom of Conus geographus that is part of the chemical arsenal used by the snail for capturing prey. This finding significantly extends known molecular mechanisms of envenomation beyond conventional neurotoxins.Unlike other fish-hunting cone snails that inject venom as they tether the prey, C. geographus engulfs its fish prey with its highly distended false mouth before venom injection (1). It has been suggested that C. geographus releases specialized toxins, called the “nirvana cabal,” into the water to suppress the sensory circuitry of schools of small fish prey (4). Our data strongly suggest that the specialized C. geographus insulin we characterized, Con-Ins G1, forms part of this venom cabal.Vertebrate insulin, synthesized in pancreatic β cells, is the key hormone regulator of carbohydrate and fat metabolism (5); in the brain, it functions as a neuromodulator of energy homeostasis and cognition (6). Insulin is initially synthesized as a precursor comprising three regions (A, B, and C) (7), from which proteolytic cleavage of the C peptide in the Golgi releases the mature insulin heterodimer with an A and B chain connected by two disulfide bonds. The A chain contains an additional intramolecular disulfide. The primary sequence and arrangement of cysteines that form disulfides are highly conserved in all vertebrates (5). In contrast, invertebrate insulin family members are more variable and serve in neuronal signaling, memory, reproduction, growth, and metabolism (8, 9). In molluscs, insulins are primarily expressed in neuroendocrine cells, including neurons and cerebral ganglia (9, 10). Molluscan and most other invertebrate insulins differ from the vertebrate hormone in containing two additional cysteines (one in each chain) that are assumed to form an additional disulfide between the A and B chain (9). Moreover, the mature molluscan insulin chains are generally larger than vertebrate insulins. Thus, sea hare (Aplysia californica) insulin (AI) has a molecular mass of 9,146 Da (10) (compared with 5,808 Da for human insulin).The venom gland of cone snails is highly specialized for conotoxin biosynthesis and secretion (11). Our discovery that an insulin is expressed in the venom gland of C. geographus at levels comparable to conotoxins was unexpected. When injected into fish this insulin significantly lowers blood glucose levels, and direct application into the water column significantly reduces locomotor activity. We show that this peptide has unusual features, including posttranslational modifications unprecedented in insulin but often found in conotoxins.