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.     

Prevalence of IgE antibody to crude and purified allergens of Japanese cedar pollen among different troops of Japanese monkeys (Macaca fuscata)

We measured specific IgE antibodies to the crude allergen as well as two purified allergens (Cry j I and Cry j II) of Japanese cedar (Cryptomeria japonica—CJ) pollen in the serum of 276 Japanese monkeys in nine troops. Of 45 monkeys with CJ specific IgE in eight of nine troops, 23 (51%) were found to have IgE to both Cry j I and Cry j II, 21 (47%) only to Cry j I, and one (2.2%) only to Cry j II. The positive rate of specific IgE antibody to each allergen varied among the troops.     

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.     

Validity of elevated interstitial levels of taurine as a predictor of myocardial ischemic injury

Summary. The microdialysis (MD) technique allows for continuous in vivo monitoring of dynamic changes in the interstitial levels of energy-related metabolites. The release of taurine from the myocyte has been suggested as a marker of ischemic injury. The relationship between (interstitial) taurine release and the degree of myocardial ischemic injury was evaluated following a 40min long ischemia in a porcine heart-infarct-model. Different protocols of ischemia and reperfusion were used in order to achieve a graded level of myocardial injury. Both interstitial peak levels and the area under curve of taurine obtained during ischemia and reperfusion correlated with the degree of ischemic injury (assessed by developed infarct size estimation). The release of taurine in the myocardium measured by the MD-technique correlated with the degree of ischemic injury during ongoing ischemic insult. Hence, taurine determination in the MD-setting represents a powerful tool to follow the development of myocardial ischemic injury over time.     

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.     

Effects of Odorants on Pigment Aggregation and cAMP in Fish Melanophores

Odor perception within olfactory neuroepithelium and pigment translocation within melanophores both seem to rely on a cAMP-based second messenger system. From studies on cultured frog melanophores, Lerner et al. (Proc. Natl. Acad. Sci. USA 85:261-264, 1988) suggested that some aspect of odor perception may be mediated by a nonspecific mechanism whose signal is transduced by a cAMP-based second messenger system. In the present study, odorants (β-ionone, benzylaldehyde, cineole, cinnamaldehyde, and octanol), which previously have been shown to stimulate formation of cAMP in the olfactory neuroepithelium, were investigated for possible pigment dispersing and cAMP-increasing effects. Pretreatment of fish melanophores with the adenylate cyclase activator forskolin (1 μM) resulted in an approximately 300% increase in cAMP and an almost complete blockage of noradrenaline-induced pigment aggregation. However, none of the tested odorants were able to increase the cAMP level and only cinnaldehyde and β-ionone were found to have any pigment dispersing activity.     

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.     

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.     

Kinetic study of racemization of aspartyl residues in synthetic elastin peptides

Summary. We previously reported that biologically uncommon D-aspartyl residues are present in sun-damaged skin from elderly people, possibly in elastin. Here, we report the kinetics of Asp racemization in model peptides corresponding to elastin sequences from exons 6 and 26. We estimated the activation energy (E) of racemization of Asp residues, the racemization rates (RR) at 37°C and the time (t) required for the D/L ratio of Asp to approximate to 1.0 (D/L ratio of Asp=0.99) at 37°C. For an exon 6 peptide, E=29.0kcal/mol, RR=2.59×10^–2/yr and t=101.0yr. For an exon 26A peptide E=26.2kcal/mol, RR=4.27×10^–2/yr and t=61.3yr; and for a second exon 26A peptide E=25.7kcal/mol, RR=5.55×10^–2/yr and t=47.0yr. These results suggest that racemization of Asp residues in elastin could occur within a human life span. We propose that D-Asp could be a useful molecular indicators of aging.     

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.     

Old views and new insights: taxonomic revision of the Bukovina blind mole rat,Spalax graecus (Rodentia: Spalacinae)

As a result of their rather uniform external appearance and gross cranial morphology, the systematics of blind mole rats has been hotly debated over the last century; however, the separation of the large‐bodied and small‐bodied blind mole rats at the genus level (Spalax and Nannospalax, respectively), suggested earlier on morphological grounds, is strongly supported by recent molecular biological evidence. The species of Spalax have so far been distinguished from each other by cranial traits only, especially the outline of sutures of the cranium, and the shape and relative size of the nasal and parietal bones. Based on mitochondrial DNA sequences (with the widest taxonomic and geographic coverage so far) and detailed anatomical comparisons of museum specimens, we herewith provide a revision of the taxonomic and phylogenetic status of the westernmost representative of the genus, Spalax graecus s.l. We clarify that antiquus and istricus – presently regarded as synonyms of graecus – are well‐defined species, and they together form a separate clade within Spalax. The robustness of our conclusions is supported by the combined evidence of morphology, multilocus phylogeny, species distribution, and taxon history (species congruence with past tectonic and climate events). © 2013 The Linnean Society of London     

Hypochlorite-induced oxidation of amino acids, peptides and proteins

Summary. Activated phagocytes generate the potent oxidant hypochlorite (HOCl) via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl is known to react with a number of biological targets including proteins, DNA, lipids and cholesterol. Proteins are likely to be major targets for reaction with HOCl within a cell due to their abundance and high reactivity with HOCl. This review summarizes information on the rate of reaction of HOCl with proteins, the nature of the intermediates formed, the mechanisms involved in protein oxidation and the products of these reactions. The predicted targets for reaction with HOCl from kinetic modeling studies and the consequences of HOCl-induced protein oxidation are also discussed.     

Production and characterization of murine monoclonal antibodies specific for baboon IgG heavy and light chain epitopes

We have generated a panel of murine monoclonal antibodies (MAbs) that recognize baboon IgG epitopes. The reactivity of the MAbs with IgG from other primate species was also examined. Specificity for IgG heavy (H) or light (L) chain epitopes was determined by Western blot analysis. The H chain-specific MAbs were analyzed for IgG subclass specificity and the L chain-specific MAbs for reactivity with baboon IgM and polymeric sIgA. Finally, an ELISA was developed to demonstrate the utility of the MAbs in analysis of humoral immune responses in baboons.     

Comparison of post-translational modifications of alpha A-crystallin from normal and hereditary cataract rats

Summary. In order to investigate the relationship between lens opacities and the various modifications of lens proteins, we analyzed and compared the properties of lens proteins of 85-day old normal Wistar rats and the hereditary cataract model, ICR/f rats. The present study identified many differences between normal and mutant lens proteins. In the ICR/f mutant rats, the relative amounts of gamma-crystallin decreased and high molecular weight (HMW) protein increased. Racemization and isomerization of Asp-151 of alpha A-crystallin was observed in the mutant ICR/f rats, and Met-1 of alpha A-crystallin was oxidized to methionine sulfoxide. These modifications were not found in the age-matched normal rats. These tendencies are consistent with aged and cataractous human lenses.     

Umbonal musculature and relationships of the Late Triassic filibranch unionoid bivalves

Exceptionally well‐preserved Late Triassic unionoids from Silesia, Poland, show prominently ornamented juvenile shells and umbonal muscle attachments that are similar to Margaritifera, which are anatomically the least derived among extant unionoids. Their phosphatized (originally chitinous and impregnated with calcium phosphate) gill supports lacked transverse connections, and occasionally some of them were separated from others, being thus at the filibranch grade, like their trigonioid ancestors. Several separate small foot elevator attachments in these unionoids indicate Trigonodidae adaptation to marine or brackish water, in which the original trigonioid strong single attachment was already split into two in the Early Triassic. The ribbing of juvenile shells suggests a change to deeper infaunal life for juvenile stages, and generally less efficient near‐surface locomotion, with a wedge‐like foot, in adults. Much later the unionoids became eulamellibranchial, which promoted the brooding of the fish that their larvae parasitize. To accomodate the classification of the order under this scenario of evolutionary changes, a new suborder Silesunionina is proposed for its filibranch members. It includes the Silesunionidae fam. nov. , with the location of umbonal muscles similar to that in the extant underived unionoids, and the Unionellidae fam. nov. , with umbonal muscles attached to the external wall of the umbonal cavity. The early Late Triassic (Carnian) Silesunio parvus gen. et sp. nov. and latest Triassic (Rhaetian) Tihkia(?) silesiaca sp. nov. are proposed. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 863–883.     

Training adaptations of baboons to light and moderate treadmill exercise

We evaluated training adaptations by 18 baboons (Papio cynocephalus anubis) to low and moderate quadrupedal walking exercise on a motorized treadmill. Moderate training produced 47% increases in lactate threshold, 63% increases in muscle citrate synthetase activity, increases in percentage of Type IIc muscle fibers, and reduced plasma insulin concentrations. Low training produced only reduced plasma insulin concentrations. Our results indicate that the baboon response to exercise training was similar to that of Homo sapiens, and dependent on exercise intensity.     

Peroxynitrite-dependent modifications of tyrosine residues in hemoglobin. Formation of tyrosyl radical(s) and 3-nitrotyrosine

Summary. Although peroxynitrite is believed to be one of the most efficient tyrosine-nitrating species of biological relevance so far identified, its nitration efficiency is nevertheless limited. In fact, the nitrating species formed through peroxynitrite decay are caged radicals (OH/NO₂ or, in the presence of carbon dioxide, CO₃ ^–/NO₂) and the fraction that escapes from the solvent cage does not exceed 30–35%. One exception may be represented by metal-containing compounds that can enhance the formation of nitrotyrosine through a bimolecular reaction with peroxynitrite. Moreover, if the metal is also regenerated in the reaction, the compound is considered a nitration catalysts and the yield of tyrosine nitration enhanced several fold. Examples of peroxynitrite-dependent nitration catalysts are the Mn-superoxide dismutase, some cytochromes and several metalloporphyrins. On the contrary, it has been claimed that some hemoproteins are scavengers of peroxynitrite and play a role in limiting its biodamaging and bioregulatory activity. In this review, we discuss the case of hemoglobin, which is probably the major target of peroxynitrite in blood. This protein has been reported to protect intracellular and extracellular targets from peroxynitrite-mediated tyrosine nitration. This property is shared with myoglobin and cytochrome c. The possible mechanisms conferring to these proteins a peroxynitrite scavenging role are discussed.Present address: Laboratorio di Tossicologia Applicata ed Ecotossicologia, Istituto Superiore di Sanità, Rome, Italy.     

Depletion of the high-abundance plasma proteins

Summary. Body fluids, like plasma and urine, are comparatively easy to obtain and are useful for the detection of novel diagnostic markers by applying new technologies, like proteomics. However, in plasma, several high-abundance proteins are dominant and repress the signals of the lower-abundance proteins, which then become undetectable either by two-dimensional gels or chromatography. Therefore, depletion of the abundant proteins is a prerequisite for the detection of the low-abundance components. We applied affinity chromatography on blue matrix and Protein G and removed the most abundant human plasma proteins, albumin and the immunoglobulin chains. The plasma proteins, prior to albumin and immunoglobulin depletion, as well the eluates from the two chromatography steps were analyzed by two-dimensional electrophoresis and the proteins were identified by MALDI-TOF-MS. The analysis resulted in the identification of 83 different gene products in the untreated plasma. Removal of the high-abundance proteins resulted in the visualization of new protein signals. In the eluate of the two affinity steps, mostly albumin and immunoglobulin spots were detected but also spots representing several other abundant plasma proteins. The methodology is easy to perform and is useful as a first step in the detection of diagnostic markers in body fluids by applying proteomics technologies.Current address: Foundation for Biomedical Research of the Academy of Athens, Greece     

Defective remethylation of homocysteine is related to decreased synthesis of coenzymes B2 in thyroidectomized rats

Summary. We investigated the influence of hypothyroidism on homocysteine metabolism in rats, focusing on a hypothetical deficient synthesis of FAD by riboflavin kinases. Animals were allocated in control group (n=7), thyroidectomized rats (n=6), rats with diet deficient in vitamin B2, B9, B12, choline and methionine (n=7), thyroidectomized rats with deficient diet (n=9). Homocysteine was decreased in operated rats (2.6±1.01 vs. 4.05±1.0mol/L, P=0.02) and increased in deficient diet rats (29.56±4.52 vs. 4.05±1.0mol/L, P=0.001), when compared to control group. Erythrocyte-Glutathione-Reductase-Activation-Coefficient (index of FAD deficiency) was increased in thyroidectomized or deficient diet rats (P=0.004 for both). Methylenetetrahydrofolate-reductase and methionine-synthase activities were decreased in thyroidectomized rats but not in those subjected to deficient diet. Cystathionine--synthase was increased only in operated rats. Taken together, these results showed a defective re-methylation in surgical hypothyroidism, which was due in part to a defective synthesis of vitamin B2 coenzymes. This defective pathway was overcompensated by the increased Cystathionine--synthase activity.