Sea snake (Microcephalophis gracilis) hemoglobin: Primary structure and relationships to other forms

The hemoglobin of the sea snakeMicrocephalophis gracilis was purified and the primary structure of the and chains determined. This is the first sea snake hemoglobin structure characterized, and apparently also the first complete structure of any snake hemoglobin (an chain of a viper was known), allowing judgments of reptilian variants. Variations between the sea snake form and other reptilian forms are large (52–65 differences for the chains), of similar order as those between the sea snake and avian (56–65 differences) or human (58 differences) forms. Functionally, 19 residues at / contact areas and 7 at heme contacts are exchanged in relation to the human and chains. Four positions of the sea snake hemoglobin contain residues thus far unique to this form. However, all replacements appear compatible with conserved overall functional properties.     

Pseudomonas 3 beta-hydroxysteroid dehydrogenase. Primary structure and relationships to other steroid dehydrogenases

The 3 beta-hydroxysteroid dehydrogenase of Pseudomonas testosteroni commercially available was purified by an FPLC step and submitted to sequence determination by peptide analysis. The structure obtained reveals a 253-residue polypeptide chain, with an N-terminal, free alpha-amino group, and a low cysteine content. Comparisons with other hydroxysteroid dehydrogenases recently characterized reveal distant similarities with prokaryotic and, to some extent, also eukaryotic forms of separate specificities. Residue identities with a Streptomyces 20 beta-hydroxysteroid dehydrogenase are 35% and distributed over the entire molecule, whereas residue identities with the mammalian 17 beta-hydroxysteroid dehydrogenase only constitute 20%, and are essentially limited to the N-terminal and central parts, Nevertheless, all these enzymes exhibit a conserved tyrosine residue (position 151 in the present enzyme) noted as possibly having a functional role in some members of this protein family. Combined, the results establish the prokaryotic 3 beta-hydroxysteroid dehydrogenase as belonging to the family of short-chain alcohol dehydrogenases, reveal that the hydroxysteroid dehydrogenases are no more closely related than dehydrogenases with other enzyme activities within the family (e.g. glucose, ribitol, hydroxyprostaglandin dehydrogenases), show several of the mammalian hydroxysteroid dehydrogenases to have subunits of longer size with different patterns of similarity than those of the prokaryotic family members characterized, and define important segments of the coenzyme-binding region for this enzyme group.     

Primary structure of hemoglobin from monitor lizard (Varanus exanthematicus albigularis--Squamata)

The primary structure of the major hemoglobin component from the Monitor Lizard Varanus exanthematicus albigularis is presented. The polypeptide subunits were separated by reversed-phase high-performance liquid chromatography on Nucleosil C-4 column. The amino-acid sequence was established by automatic Edman degradation of the native polypeptide and its tryptic and hydrolytic cleavage products in a spinning cup sequencer. The structural data are discussed with reference to other reptiles.     

Primary structure of hemoglobin from gray partridge (Francolinus pondacerianus, Galliformes)

The complete amino acid sequence of the ^A-chain of major hemoglobin component from gray partridgeFrancolinus pondacerianus is presented. The major component HbA accounts for 75% of the total hemolysate. Separation of the globin subunits was achieved by ion-exchange chromatography on CM-Cellulose in 8 M urea. The sequence was studied by automatic Edman degradation of the native chain and its tryptic peptides in a gas-phase sequencer. The phylogenetic relationship of Galliformes with other avian orders is discussed.     

Primary structure of the hemoglobin alpha-chain of rose-ringed parakeet (Psittacula krameri)

The structure of the hernoglobin -chain of Rose-ringed Parakeet was determined by sequence degradations of the intact subunit, the CNBr fragments, and peptides obtained by digestion with staphylococcal Glu-specific protease and trypsin. Using this analysis, the complete -chain structure of 21 avian species is known, permitting comparisons of the protein structure and of avian relationships. The structure exhibits differences from previously established avian -chains at a total of 61 positions, five of which have residues unique to those of the parakeet (Ser-12, Gly-65, Ser-67, Ala-121, and Leu-134). The analysis defines hemoglobin variation within an additional avian order (Psittaciformes), demonstrates distant patterns for evaluation of relationships within other avian orders, and lends support to taxonomic conclusions from molecular data.     

Primary structure of the hemoglobin beta-chain of rose-ringed parakeet (Psittacula krameri)

The primary structure of Rose-ringed Parakeet hemoglobin -chain was established, completing the analysis of this hemoglobin. Comparisons with other avian -chains show variations smaller than those for the corresponding -chains. There are 11 amino acid exchanges in relationship to the only other characterized psittaciform -chain, and a total of 35 positions are affected by differences among all avian -chains analyzed (versus 61 for the -chains). At three positions, the Psittacula -chain has residues unique to this species. Three ₁₁ contacts are modified, by substitutions at positions 51, 116, and 125.     

The primary structure of the hemoglobin of Malayan sun bear (Helarctos malayanus, Carnivora) and structural comparison to other hemoglobin sequences

The complete primary structure of the alpha- and beta-chains of the hemoglobin of Malayan Sun Bear (Helarctos malayanus) is presented. After cleavage of the heme-protein link and chain separation by RP-HPLC, amino-acid sequences were determined by Edman degradation in liquid- and gas-phase sequenators. An interesting result of this work is the demonstration that the hemoglobin of Malayan Sun Bear is identical to the hemoglobins of Polar Bear (Ursus maritimus) and Asiatic Black Bear (Ursus tibetanus). The paper gives an updated table of identical hemoglobin chains from different species. This paper may be considered as a compilation of work on the genetic relationship of Pandas.     

Two new Zoopsis species and their relationships to other zoopsids (Jungermanniopsida: Lepidoziaceae)

Abstract

We describe and illustrate two highly distinctive new species of Zoopsis from New Zealand. To assess their relationships to other species we performed parsimony and splits-based analysis of morphological data. Our analysis resolves Zoopsis bicruris as a member of subgenus Zoopsis, but is inconclusive with respect to the affinities of Z. matawaia. Our analysis groups Zoopsis matawaia with Z. ceratophylla and Zoopsidella caledonica, on the basis of their shared possession of caducous leaf lobes. The interpretation of this character as a defining apomorphy is at odds with currently accepted hypotheses of character evolution, which regard it as symplesiomorphic, and regard reduced seta anatomy as an apomorphy defining Zoopsidella. However, trees constrained to retain Zoopsidella as a monophyletic unit were two steps longer than unconstrained trees, and had slightly poorer measures of support. Our analysis resolves Monodactylopsis nested within Zoopsidella, which is in turn nested within Zoopsis, and identifies Hyalolepidozia as sister to a clade corresponding to the Zoopsidoideae with moderate bootstrap support.     

Ultrastructure of maturing fish (Oreochromis niloticus) and snake (Waglerophis merremii) erythroid cells with regard to hemoglobin biosynthesis

• 1.1. Fish and snake immature erythrocytes were submitted to a comparative ultrastructural study, analysing changes in organelles involved in hemoglobin (Hb) biosynthesis.
• 2.2. Iron uptake occurs probably via transferrin, and ferruginous compounds accumulate as siderosomes, taken as iron sources for heme biosynthesis, later on caught by a double lamella.
• 3.3. Mitochondrial membrane of the inner camera differentiates to lamellated bodies that, sucessively, give rise to expansions for ferruginous material and globin chains captation, constituting prehemosomal vesicles, which become condensed vesicles, followed by prohemosomes.
• 4.4. Through an internal membrane rearrangement, prohemosomes change to hemosomes wherein, hypothetically, heme and the globin chains assembly may occur.
• 5.5. In both fish and snake erythroid cells, all stages for hemosomegenesis are similar to the stages found in erythroid cells of other vertebrate species, including humans, except that fish cells often present single organelles of still unknown function, void of internal membrane.
• 6.6. Through electrophoresis of the respective supernatants obtained after osmotical lysis of the organellar fractions, it was shown that fish hemosomes contain three Hb patterns, while snake hemosomes present two patterns.

     

Rat liver alcohol dehydrogenase of class III. Primary structure, functional consequences and relationships to other alcohol dehydrogenases

The amino acid sequence of alcohol dehydrogenase of class III from rat liver (the enzyme ADH-2) has been determined. This type of structure is quite different from those of both the class I and the class II alcohol dehydrogenases. The rat class III structure differs from the rat and human class I structures by 133-138 residues (exact value depending on species and isozyme type); and from that of human class II by 132 residues. In contrast, the rat/human species difference within the class III enzymes is only 21 residues. The protein was carboxymethylated with iodo[2(14)C]acetate, and cleaved with CNBr and proteolytic enzymes. Peptides purified by exclusion chromatography and reverse-phase high-performance liquid chromatography were analyzed by degradation with a gas-phase sequencer and with the manual 4-N,N-dimethylaminoazobenzene-4'-isothiocyanate double-coupling method. The protein chain has 373 residues with a blocked N terminus. No evidence was obtained for heterogeneity. The rat ADH-2 enzyme of class III contains an insertion of Cys at position 60 in relation to the class I enzymes, while the latter alcohol dehydrogenase in rat (ADH-3) has another Cys insertion (at position 111) relative to ADH-2. The structure deduced explains the characteristic differences of the class III alcohol dehydrogenase in relation to the other classes of alcohol dehydrogenase, including a high absorbance, an anodic electrophoretic mobility and special kinetic properties. The main amino acid substitutions are found in the catalytic domain and in the subunit interacting segments of the coenzyme-binding domain, the latter explaining the lack of hybrid dimers between subunits of different classes. Several substitutions provide an enlarged and more hydrophilic substrate-binding pocket, which appears compatible with a higher water content in the pocket and hence could possibly explain the higher Km for all substrates as compared with the corresponding values for the class I enzymes. Finally the class III structure supports evolutionary relationships suggesting that the three classes constitute clearly separate enzymes within the group of mammalian zinc-containing alcohol dehydrogenases.     

Postovipositional development of the sand snake Psammophis sibilans (Serpentes:Lamprophiidae) in comparison with other snake species

Characterizing and comparing developmental progress across different species helps to interpret how different or similar body forms evolved. We present an embryonic table for the oviparous African Sand Snake Psammophis sibilans from the Lamprophidae family, describing its postovipositional in ovo development. Psammophis is a good model of a genus that is widely distributed in Africa and Asia and includes 22 species. We describe ten embryonic stages based on the development of externally visible morphological characteristics such as; pharyngeal arches, facial processes, eyes, scales, body pigmentation and body colour pattern development. This study discusses the development of this snake and compares it with that of the closely related brown house snake Lamprophis fulliginosus (Lamprophidae) and the medically important venomous cobras Naja haje haje and Naja kaouthia from the sister lineage Elapidae. The distantly related basal snake Python sebae, which displays different morphology and behaviour, was chosen for deeper insight into the evolution of body structures within the snake clade. We found interspecific differences in the relative stage of development of embryonic structures at the time of oviposition and during postovipositional embryonic development. One of the outcomes of this study is that embryonic structures such as the pharyngeal processes, eye pigmentation and scales are interspecifically conservative in regard to timing of morphodifferentiation, while body pigmentation, colour and colour pattern are interspecifically plastic in their temporospatial development.     

Evolutionary relationships and implications for the regulation of phospholipase A2 from snake venom to human secreted forms

Summary The amino acid sequences of 40 secreted phospholipase A₂'s (PLA₂) were aligned and a phylogenetic tree derived that has three main branches corresponding to elapid (group I), viperid (group II), and insect venom types of PLA₂. The human pancreatic and recently determined nonpancreatic sequences in the comparison align with the elapid and viperid categories, repectively, indicating that at least two PLA₂ genes existed in the vertebrate line before the divergence of reptiles and mammals about 200–300 million years ago. This allows resolution for the first time of major genetic events in the evolution of current PLA₂'s and the relationship of human PLA₂'s to those of snake venom, many of which are potent toxins. Implications for possible mechanisms of regulation of mammalian intra- and extracellular PLA₂'s are discussed, as well as issues relating to the search for the controlling enzymes in arachidonic acid release, prostaglandin generation, and signal transduction.     

Floral structure and relationships ofHortonia (Monimiaceae)

The flowers ofHortonia angustifolia were investigated for their phyllotaxis, morphology, anatomy and development of the perianth, androecium and gynoecium. Certain features were also studied inH. ovalifolia. Characters so far overlooked further support the isolated and intermediate position of the genus between theAtherospermataceae andMonimiaceae s. str. and its archaic position among theLaurales. Dedicated to Professor Dr.W. Leinfellner on the occasion of his 70th birthday.     

Sea snake skin: Permeable to water but not to sodium

Summary Fasting yellow-bellied sea snakes (Pelamis) have a very low rate of exchange of Na with sea water. Influx and efflux are balanced at a value near 8 moles/100 g h. This is only a fraction of the rate of exchange found in marine fish. Na influx is due to uptake in the head region; dermal and cloacal influx are minimal. The impermeability of the skin to Na has been confirmed in isolated preparations. The outer keratin layer seems to be the primary barrier, since the shed skin alone is also impermeable. Na efflux can be increased to 140 m/100 g h by salt injections, and secretion by the sublingual salt gland can account for all of this loss. Fasting snakes are not in water balance in sea water. There is a net loss of water amounting to about 0.4% body wt/day that probably occurs mainly through the skin. The major osmotic problem ofPelamis in sea water seems to be water balance, not salt balance. Differences in salt gland size among sea snakes might be related to differences in skin permeability to water associated with dermal respiration. The importance of the skin as a permeability barrier suggests that the frequent skin shedding of sea snakes may be related to maintenance of low water permeability as well as to prevention of growth by marine fouling organisms.     

Gynostemium structure and relationships of theCorallorhizinae (Orchidaceae: Epidendroideae)

Several types of pollinium stalk are present in theCorallorhizinae. Govenia has a cellular epidermal pollinium stalk, whileTipularia has a unique stipe that results from prolongation and detachment of the rostellum.Dactylostalix andEphippianthus have no stipe, but do have a detachable viscidium.Aplectrum, Corallorhiza, Cremastra, andOreorchis have hamuli. Cladistic analysis of morphological characters suggests that these four genera form a coreCorallorhizinae, and are sister group to a clade includingTipularia, Calypso, andYoania (the latter two possessing a true tegula).Govenia is shown to be most closely related to cymbidioid genera (such asEulophia), sharing with them the cellular epidermal pollinium stalk andCymbidium type velamen, and indicating that removal ofGovenia fromCorallorhizinae is appropriate.Dactylostalix andEphippianthus appear to occupy a more basal position in the subfamily, further arguing that the subtribe as previously recognized is paraphyletic.     

Primary structure of the chromosomal origins (oriC) of Enterobacter aerogenes and Klebsiella pneumoniae: comparisons and evolutionary relationships

The nucleotide sequences of the Enterobacter aerogenes and Klebsiella pneumoniae DNA replication origins (oriC) were determined and compared with those of Escherichia coli and Salmonella typhimurium. Four interrelated, 9-base-pair repeats were identified from the conserved regions within the minimal origin. Evolutionary rates calculated from the minimal origin sequences yielded a quantitative phylogenic tree which agreed with the taxonomic classification of these genera.     

Primary structure, biochemical and physiological aspects of hemoglobin from South American lungfish (Lepidosiren paradoxus, Dipnoi)

The South American Lungfish has only one hemoglobin component. The complete amino-acid sequence of this hemoglobin is presented. A large quantity of carbonate dehydratase from the lungfish erythrocytes was also isolated. The carboxymethylated chains, obtained by separation of globin on DEAE-Sephacel, were submitted to tryptic digestion and chemical cleavage. The isolation of tryptic peptides was achieved either by Dowex-50 chromatography or by high performance liquid chromatography. The alignment of peptides was performed by homology with the previously established sequences of the carp and goldfish hemoglobins. The overlapping peptides confirmed this sequence. The alpha chains have 143 residues, the beta chains 147. The relation between the primary structure and the physiological properties of lungfish hemoglobin are discussed.     

Homeothermic fish and hemoglobin: primary structure of the hemoglobin from bluefin tuna (Thunnus thynnus, Scromboidei)

Some fish are warm-bodied, e.g. the bluefin tuna (Thunnus thynnus), which has a muscle temperature 12-17 degrees C higher than its environment. This endothermy is achieved by aerobic metabolism and conserved by means of a heat-exchanger system. The hemoglobins of bluefin tuna are adapted to these conditions by their endothermic oxygenation, thus contributing to the preservation of the body energy. This is a new and so far unique property of tuna hemoglobin. The primary structure of the alpha and beta chains of bluefin tuna hemoglobins is presented. The sequence was determined after enzymatic and chemical cleavages of the chains and sequencing of the peptides in gas- and liquid-phase sequencers. The alpha chains consists of 143 residues and are N-terminally acetylated. The beta chains have 146 amino acids and show two ambiguities at positions 140 and 142. The alpha chains differ from the human alpha chains in 65 amino-acid residues, the beta chains in 76. The hemoglobins of bluefin tuna, carp and man are compared and their different physiological properties are discussed in relation to the sequence data. From the primary structure of tuna hemoglobins, it is possible to propose a molecular basis for their peculiar endothermic transition from the T to the R structure.