Phylogenetics and biogeography of the Balkan ‘sand gobies’ (Teleostei: Gobiidae): vulnerable species in need of taxonomic revision

Within the Atlantic–Mediterranean region, the ‘sand gobies’ are abundant and widespread, and play an important role in marine, brackish, and freshwater ecosystems. They include the smallest European freshwater fish, Economidichthys trichonis, which is threatened by habitat loss and pollution, as are several other sand gobies. Key to good conservation management is an accurate account of the number of evolutionary significant units. Nevertheless, many taxonomic and evolutionary questions remain unresolved within the clade, and molecular studies are lacking, especially in the Balkans. Using partial 12S and 16S mitochondrial ribosomal DNA sequences of 96 specimens of at least eight nominal species (both freshwater and marine populations), we assess species relationships and compare molecular and morphological data. The results obtained do not support the monophyly of Economidichthys, suggesting the perianal organ to be a shared adaptation to hole‐brooding rather than a synapomorphy, and urge for a taxonomic revision of Knipowitschia. The recently described Knipowitschia montenegrina seems to belong to a separate South‐East Adriatic lineage. Knipowitschia milleri, an alleged endemic of the Acheron River, and Knipowitschia cf. panizzae, are shown to be very closely related to other western Greek Knipowitschia populations, and appear conspecific. A distinct Macedonian–Thessalian lineage is formed by Knipowitschia thessala, whereas Knipowitschia caucasica appears as an eastern lineage, with populations in Thrace and the Aegean. The present study combines the phylogeny of a goby radiation with insights on the historical biogeography of the eastern Mediterranean, and identifies evolutionary units meriting conservation attention. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 73–91.     

Arginine pathways and the inflammatory response: Interregulation of nitric oxide and polyamines: Review article

Summary. An early response to an acute inflammatory insult, such as wound healing or experimental glomerulonephritis, is the conversion of arginine to the cytostatic molecule nitric oxide (NO). This anti-bacterial phase is followed by the conversion of arginine to ornithine, which is the precursor for the pro-proliferative polyamines as well as proline for the production of extracellular matrix. This latter, pro-growth phase constitutes a repair phase response. The temporal switch of arginine as a substrate for the cytostatic iNOS/NO axis to the pro-growth arginase/ ornithine/polyamine and proline axis is subject to regulation by inflammatory cytokines as well as interregulation by the arginine metabolites themselves. Arginine is also the precursor for another biogenic amine, agmatine. Here we describe the capacity of these three arginine pathways to interregulate, and propose a model whereby agmatine has the potential to serve in the coordination of the early and repair phase pathways of arginine in the inflammatory response by acting as a gating mechanism at the transition from the iNOS/NO axis to the arginase/ODC/polyamine axis. Due to the pathophysiologic and therapeutic potential, we will further examine the antiproliferative effects of agmatine on the polyamine pathway.     

Biochemical properties of new synthetic carnosine analogues containing the residue of 2,3-diaminopropionic acid: the effect of N-acetylation

Summary. Three novel carnosine analogues 7–9 containing the residue of L(+)2,3-diaminopropionic acid with different degree of N-acetylation instead of -alanine have been synthesized and characterized. Comparative analysis of hydrolysis by carnosinase revealed that the mono- and bis-acetylated compounds 8 and 9 are resistant to enzymatic hydrolysis and act as competitive inhibitors of this enzyme. The hydroxyl radical scavenging potential of the three analogues was evaluated by their ability to inhibit iron/H₂O₂-induced degradation of deoxyribose. The second-order rate constants of the reaction of compounds 7–9 with hydroxyl radical were almost identical to that of carnosine. These compounds were also found to act as protective agents against peroxynitrite-dependent damage as assessed by their ability to prevent nitration of free tyrosine induced by this species.     

Inhibitors of polyamine metabolism: Review article

Summary. The identification of increased polyamine concentrations in a variety of diseases from cancer and psoriasis to parasitic infections has led to the hypothesis that manipulation of polyamine metabolism is a realistic target for therapeutic or preventative intervention in the treatment of certain diseases.The early development of polyamine biosynthetic single enzyme inhibitors such as -difluoromethylornithine (DFMO) and methylglyoxal bis(guanylhydrazone) showed some interesting early promise as anticancer drugs, but ultimately failed in vivo. Despite this, DFMO is currently in use as an effective anti-parasitic agent and has recently also been shown to have further potential as a chemopreventative agent in colorectal cancer.The initial promise in vitro led to the development and testing of other potential inhibitors of the pathway namely the polyamine analogues. The analogues have met with greater success than the single enzyme inhibitors possibly due to their multiple targets. These include down regulation of polyamine biosynthesis through inhibition of ornithine decarboxylase and S-adenosylmethionine decarboxylase and decreased polyamine uptake. This coupled with increased activity of the catabolic enzymes, polyamine oxidase and spermidine/spermine N¹-acetyltransferase, and increased polyamine export has made the analogues more effective in depleting polyamine pools. Recently, the identification of a new oxidase (PAO-h1/SMO) in polyamine catabolism and evidence of induction of both PAO and PAO-h1/SMO in response to polyamine analogue treatment, suggests the analogues may become an important part of future chemotherapeutic and/or chemopreventative regimens.     

Theoretical studies of biliverdin: energetics of the reduction pathways to bilirubin

Geometries and energies of formation of bilirubin formed by reduction of biliverdin via three meso carbon sites, the , and positions, have been calculated using semiempirical methods. It has been shown that -bilirubin with a ridge-tile conformation forms six intramolecular hydrogen bonds and is the most stable of the three above mentioned positions by at least 22 kcal mol^–1. Reduction pathways for -, - and -bilirubin formations from biliverdin are studied in detail. The roles of loss of conjugation and hydrogen bond formations in stability of different conformers have been discussed. -Bilirubin was fully optimized by using ab initio methods. Fine refinements of calculated results show excellent agreement with experimental results. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00894-002-0078-9.Electronic Supplementary Material available.     

Patterns of diversification in two species of short‐tailed bats (Carollia Gray, 1838): the effects of historical fragmentation of Brazilian rainforests

The small‐sized frugivorous bat Carollia perspicillata is an understory specialist and occurs in a wide range of lowland habitats, tending to be more common in tropical dry or moist forests of South and Central America. Its sister species, Carollia brevicauda, occurs almost exclusively in the Amazon rainforest. A recent phylogeographic study proposed a hypothesis of origin and subsequent diversification for C. perspicillata along the Atlantic coastal forest of Brazil. Additionally, it also found two allopatric clades for C. brevicauda separated by the Amazon Basin. We used cytochrome b gene sequences and a more extensive sampling to test hypotheses related to the origin and diversification of C. perspicillata plus C. brevicauda clade in South America. The results obtained indicate that there are two sympatric evolutionary lineages within each species. In C. perspicillata, one lineage is limited to the Southern Atlantic Forest, whereas the other is widely distributed. Coalescent analysis points to a simultaneous origin for C. perspicillata and C. brevicauda, although no place for the diversification of each species can be firmly suggested. The phylogeographic pattern shown by C. perspicillata is also congruent with the Pleistocene refugia hypothesis as a likely vicariant phenomenon shaping the present distribution of its intraspecific lineages. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 527–539.     

Patterns of morphological evolution of the cephalic region in damselfishes (Perciformes: Pomacentridae) of the Eastern Pacific

Pomacentridae are one of the most abundant fish families inhabiting reefs of tropical and temperate regions. This family, comprising 29 genera, shows a remarkable diversity of habitat preferences, feeding, and behaviours. Twenty‐four species belonging to seven genera have been reported in the Eastern Pacific region. The present study focuses on the relationship between the diet and the cephalic profile in the 24 endemic damselfishes of this region. Feeding habits were determined by means of underwater observations and the gathering of bibliographic data. Variations in cephalic profile were analyzed by means of geometric morphometrics and phylogenetic methods. The present study shows that the 24 species can be grouped into three main trophic guilds: zooplanktivores, algivores, and an intermediate group feeding on small pelagic and benthic preys. Shape variations were low within each genus except for Abudefduf. Phylogenetically adjusted regression reveals that head shape can be explained by differences in feeding habits. The morphometric phylogeny recovered the subfamily Stegastinae and the relationship between Abudefduf troschelii and Chromis species. The cephalic profile of damselfishes contains a clear and strong phylogenetic signal. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 593–613.     

Revision of the Euthalia phemius complex (Lepidoptera: Nymphalidae) based on morphology and molecular analyses

Adults of the Euthalia phemius complex, which is composed of three South‐East Asian nymphalid species, Euthalia phemius, Euthalia ipona, and Euthalia euphemia, were genetically analysed by examining mitochondrial and nuclear genes. The E. phemius complex was also examined morphologically, with particular emphasis on wing markings and male genitalia. No significant differences amongst the three species in the complex were detected with respect to either genetic distance or genital morphology. We therefore conclude that the three currently recognized Euthalia species belong to a single species. Accordingly, E. ipona is synonymized with E. phemius. Euthalia euphemia is treated as a subspecies of E. phemius. Type specimens of all taxa and a synonymic list for the E. phemius complex are also given. In addition, we briefly discuss the evolution and biogeography of the species complex. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 304–327.     

Biochemical mechanisms for a possible involvement of the transglutaminase activity in the pathogenesis of the polyglutamine diseases: Minireview article

Summary. Transglutaminases are a family of enzymes which show the common capacity to catalyse the cross-linking of protein substrates. Some members of this family of enzymes are also capable to catalyse other chemical reactions for the cell life. The distribution and the role of these enzymes have been studied in numerous cell types and tissues, but only recently their expression and functions started to be investigated in the Nervous System. One of the main biochemical properties of the Transglutaminase enzymes is to form large protein aggregates that are insoluble in all known protein detergents. Recently, the Transglutaminase activity has been hypothesised to be involved in the pathogenetic mechanisms responsible for the formation of cellular inclusions present in the Corea Major and in other polyglutamine diseases. In this review we describe the biochemical mechanisms by which the Transglutaminases could play a critical role in the physiopathology of the polyglutamine diseases.     

Structure and distribution of floral trichomes in Lycaste and Sudamerlycaste (Orchidaceae: Maxillariinae s.l.)

Phylogenetic analysis indicates that Lycastinae should be incorporated into a more broadly defined Maxillariinae. This is supported by several anatomical features, including the presence of sunken, glandular trichomes in both Lycastinae and Maxillariinae s.s. Until recently, these were known only from vegetative organs, but have since been reported from flowers of Maxillaria dichroma. One character currently used to distinguish between Lycaste and Sudamerlycaste is the distribution of floral trichomes. In this article, we test the reliability of this character, describe the floral micromorphology of Lycaste and Sudamerlycaste and investigate whether their flowers bear sunken hairs. Their floral micromorphology is compared with that of other genera currently assigned to Maxillariinae s.l. Flowers of Lycaste and Sudamerlycaste bear conical or obpyriform papillae and unbranched and unequally branched multicellular trichomes. Contrary to previous reports that trichomes are confined to the column in Sudamerlycaste, they also occur in the tepal axils. Labellar trichomes, although often present in Lycaste, are lacking in Sudamerlycaste. In Lycaste sections Lycaste and Aromaticae, floral trichomes tend to be unbranched, whereas section Intermediae has both unbranched and branched hairs. Branched hairs are more common in Sudamerlycaste. Some hairs are tracheoidal, pitted and lignified. These mainly occur in section Lycaste and, to a degree, in section Intermediae, but are absent from section Aromaticae and most species of Sudamerlycaste. Branched column hairs, present in Sudamerlycaste, are absent from all sections of Lycaste, and tracheoidal column hairs occur only in Sudamerlycaste. Sunken floral hairs are absent from both genera. Trichome structure and distribution may prove useful in distinguishing between these taxa and in elucidating the intergeneric relationships of Maxillariinae s.l.© 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 409–421.     

Modularity in attachment organs of African Cichlidogyrus (Platyhelminthes: Monogenea: Ancyrocephalidae) reflects phylogeny rather than host specificity or geographic distribution

Cichlidogyrus spp. (Monogenea, Ancyrocephalidae) are common parasites of cichlid fishes from Africa and the Levant. They display important morphological variation in their attachment apparatus and infect a broad host spectrum throughout a wide geographic range. Thus, they offer an interesting model to investigate to what extent the phenotypic variability of the attachment organ among congeners is related to host specificity, geographic/environmental components, or phylogeny. A geometric morphometric approach was carried out to analyse the shape variation of sclerotized structures of the attachment organ within 66 African species of the genus Cichlidogyrus. The interspecific shape comparison supports the presence of three main morphological configurations, each consisting of a given combination of particular sclerite shapes. Moreover, data emphasize strong coordination and integration (shape co‐variation) among the different sclerites jointly forming the attachment organ. Although attachment apparatuses are usually considered to be the result of adaptive processes and must be adapted to the hosts and local environmental conditions, we found no relationship between these clusters and host specificity or geographical distribution. Nevertheless, groups are partially congruent with those obtained with the molecular phylogeny of a subset of species, suggesting a phylogenetic constraint rather than an adaptation to either hosts or environment. Because of the necessity to form a functional entity, modularity within attachment organ imposes important evolutionary constraint. This provides new insights into the evolvability of attachment organs, as well as into the morphological basis of host specificity and host–parasite co‐evolutionary interaction in helminth parasites. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 694–706.     

Endogenous Control of Photosynthetic Activity during Progressive Drought: Influence of Final Products of Photosynthesis

Photosynthetic activities and the redox states of photosystem I (PSI) and photosystem II (PSII) in intact leaves of cucumber plants (Cucumis sativus L.), as well as the sucrose and starch contents were examined under conditions of ongoing soil water deficit imposed by the cessation of watering. As the soil drought progressed, the maximum rate of photosynthetic CO₂ fixation was shown to decrease. These changes in the maximum photosynthetic rate occurred synchronously with changes in the maximum quantum yield of photosynthesis. Under soil water deficit, the reduced form of PSII primary acceptor Q _A was accumulated only at photon flux densities of about 100 mol/(m² s). At such photon flux densities, the changes in nonphotochemical quenching (qN) induced by soil water deficit were opposite to changes in photochemical quenching parameter (1 – qP). Irrespective of the duration of soil drought, the relationship between steady-state concentrations of photochemically inactive reaction centers of PSI and PSII (the fractions of P700 and Q _A in the oxidized and reduced state, respectively) was almost linear, which provides evidence for the concerted operation of both photosystems. The conditions of soil water deficit promoted sucrose accumulation in the source leaf, which was paralleled by a substantial decrease in the amount of starch in the same leaf. The highest content of sucrose in the leaf after a 7-day drought was correlated with the largest decrease in photosynthetic activity. It is concluded that the progressive drought triggers an endogenous mechanism that regulates photosynthesis through feedback relations, namely, the inhibition of photosynthesis by its end products.     

Polyamines and cancer: Minireview article

Summary. The naturally occurring polyamines, spermine, spermidine and the diamine putrescine are widespread in nature. They have been implicated in growth and differentiation processes. Polyamines accumulate in cancerous tissues and their concentration is elevated in body fluids of cancer patients. Assays of urinary and blood polyamines have been used to detect cancer and to determine the success of therapy. Drugs which inhibit the synthesis of polyamines can prevent cancer and may also be used for therapeutic purposes. Ornithine decarboxylase, which catalyzes the rate limiting step in polyamine synthesis, can serve as a marker of proliferation. Recently, a new in vitro chemosensitivity test, based on the disappearance of ornithine decarboxylase in drug-treated cancer cells has been developed. The increasing interest in polyamines and their physiological functions may lead to a more extensive application of these compounds or their derivatives in cancer diagnosis and treatment.     

The transglutaminase family: an overview: Minireview article

Summary. The knowledge that very different processes such as normal and neoplastic cell growth, reproduction and death are dependent on the presence of adequate levels of transglutaminases (TGase: EC 2.3.2.13) and that they are capable of affecting the differentiation and proliferative capability of several cell types, has prompted a multitude of researchers to study these fascinating molecules. In the following overview we intend to summarize the currently known information on the biological significance of these enzymes.     

Excitotoxic and post-ischemic neurodegeneration: Involvement of transglutaminases

Summary. Neurodegeneration induced by excitotoxicity is a common feature in various neurological disorders. This pathological condition is caused by prolonged stimulation of glutamate receptor subtypes, followed by both intracellular Ca²⁺ overload and activation of specific genes, resulting in synthesis of enzymes involved in cell stress response.Using experimental in vitro models of excitotoxicity, we demonstrated that glutamate exposure up-regulated tissue transglutaminase in primary cultures of both cerebellar granule cells and astrocytes. These changes were consequent to receptor-mediated Ca²⁺ influx, as demonstrated by the inhibition with selective antagonists, MK-801 and GYKI 52466. Early increases in different transglutaminase isoforms were also observed in global cerebral ischemia, which closely resembles neuronal damage caused by NMDA receptor activation.These findings agree with a postulated role for transglutaminases in molecular mechanisms of several neurodegenerative diseases. Indeed, increased cross-linking reactions could be of pathologic relevance, as part of biochemical changes observed in neurological disorders.     

N-Terminal pyrazinones: a new class of peptide-bound advanced glycation end-products

Summary. The reaction of peptide Gly-Ala-Phe with the -dicarbonyl compounds glyoxal and methylglyoxal was studied under physiological conditions (pH=7.4, 37°C). Using HPLC with UV and fluorescence detection, a rapid derivatization of the peptide and the concomitant formation of well-defined products were observed. The products, which showed characteristic UV absorbance (_max=320 to 340nm) and fluorescence (_ex=330 to 340nm, _em=395 to 405nm), were identified by ESI-MS and NMR spectroscopic analysis as the N-terminally pyrazinone-modified peptides I (N-[2-(2-oxo-2H-pyrazin-1-yl)-propyl]-phenylalanine) and II (N-[2-(5-methyl-2-oxo-2H-pyrazin-1-yl)-propionyl]-phenylalanine). Model experiments revealed that the reactivity of the N-termini of peptides towards a derivatization by glyoxal is in the same order of magnitude as that of arginine, which generally is attributed as main target for -dicarbonyl compounds in proteins. Incubation of insulin with glyoxal proved the protein-bound formation of pyrazinones, with the N-terminus of the B-chain as the main target. According to these results, we conclude that N-terminal pyrazinones represent a new type of advanced glycation end-products (AGEs) with significance for biological systems and foods.     

The biological functions of polyamine oxidation products by amine oxidases: Perspectives of clinical applications

Summary. The polyamines spermine, spermidine and putrescine are ubiquitous cell components. If they accumulate excessively within the cells, due either to very high extracellular concentrations or to deregulation of the systems which control polyamine homeostasis, they can induce toxic effects. These molecules are substrates of a class of enzymes that includes monoamine oxidases, diamine oxidases, polyamine oxidases and copper containing amine oxidases. Polyamine concentrations are high in growing tissues such as tumors. Amine oxidases are important because they contribute to regulate levels of mono- and polyamines. These enzymes catalyze the oxidative deamination of biogenic amines and polyamines to generate the reaction products H₂O₂ and aldehyde(s) that are able to induce cell death in several cultured human tumor cell lines. H₂O₂ generated by the oxidation reaction is able to cross the inner membrane of mitochondria and directly interact with endogenous molecules and structures, inducing an intense oxidative stress. Since amine oxidases are involved in many crucial physiopathological processes, investigations on their involvement in human diseases offer great opportunities to enter novel classes of therapeutic agents.     

Biogenic amines and apoptosis: Minireview article

Summary. The programmed cell death is a very complex mechanism involving many factors, among them the intracellular concentration of biogenic amines (BA) appears to be important for apoptosis triggering. The mitochondrial damage is imputable to hydrogen peroxide and aldehydes, produced by amine oxidases (AO)-mediated oxidation of BA. On the other hands, the apoptosis protection observed by high BA concentration appears to be related to their scavenger effect of ROS and/or their interaction with membrane pores. Also monoamine oxidase (MAO) inhibitors, like propargylamines, preserve the mitochondria integrity by inhibiting MAO and therefore the production of H₂O₂ and aldehydes and, as cations, by regulating membrane pores, like BA.As general conclusion, apoptosis is protected by high concentration of BA and/or other cations while it is favoured by ROS produced by AOs or other mechanisms.