Synthesis and Cytostatic Activity of Halomethylthiazole C-Nucleosides and Analogues1

Abstract

The synthesis of 2-(β-D-ribofuranosyl)-and 2-(tetrahydropyran-2-yl)-4-halomethylthiazoles from 2, 5-anhydro-D-allonthioamide and tetrahydropyran-2-thiocarboxamide is described. Bromination of 2-(β-D-ribofuranosyl)- and 2-tetrahydropyran-2-yl)-4-methylthiazole with NBS is studied. Cytostatic activity against HeLa cells of all the compounds is reported.     

Benzyladenine and derivatives-their significance and interconversion in plants

Recently benzyladenine has been isolated as a natural cytokinin from a number of plants. The natural occurrence of this cytokinin will change the attitude with which physiologists view this hormone. This review attempts to put into context what is known about this cytokinin and its derivatives and to compare and contrast its metabolism and the function and physiological action of its various metabolites. Nothing is known about the biosynthesis of benzyladenine. Its structure would suggest that its biosynthetic pathway may differ considerably from that of zeatin and iso-pentenyladenine.Abbreviations Ade adenine - Ado adenosine - BA benzyladenine - [9R]BA BA ribonucleoside - [9R-MP]BA BA nucleotide - [9R-DP]BA BA dinucleotide - [9R-TP]BA BA trinucleotide - [3G]BA BA 3 glucoside - [7G]BA BA 7 glucoside - [9G]BA BA 9 glucoside - [9R-G]BA BA 9-ribosylglucoside - [9Ala]BA BA alanine-conjugate - (2OH)BA BA ortho-OH - (2OH)[9R]BA BA ortho-Oh-riboside - KN kinetin - [9R]KN KN ribonucleoside - DHZ dihydrozeatin - Z trans-zeatin - [9R]Z zeatin ribonucleoside - [7G]Z zeatin-7-glucoside - [9G]Z zeatin-9-glucoside - [9Ala]Z zeatin alanine-conjugate - (OG)[9R]Z O-glucoside of zeatin ribonucleoside - [9R-MP]Z zeatin nucleotide - iP iso-pentenyladenine - [9R]iP iP ribonucleoside     

Neuroendocrine heart and hypothalamus

Data on the endocrine heart—neurosecretory cells of heart, producing coronarydilatory, metabolically active glycopeptides with physico-chemical and biological properties similar to those of previously discovered cardioactive hypothalamic neurohormones—are summarized. Heart hormones participate in both local and distant regulation of heart metabolism and function. Formation and action of these heart hormones is closely related to hypothalamic cardioactive neurohormones K, C, and G and their protein precursors. Neurohormones from heart and hypothalamus comprise a system of neurohumoral connections between these two organs. A possible role of APUD cells in the generation of a number of heart peptides and glycopeptides exerting hormonal activity is discussed.Abbreviations Used NC Neurohormone C - NK Neurohormone K - NC-H Hypothalamic NC - NK-H Hypothalamic NK - PC-NC NC cleaved from protein-carrier - PC-NK NK cleaved from protein-carrier - BB-NC Brain blood NC - BB-NK Brain blood NK - H₁ Substrate 1 from heart - H₂ Substrate 2 from heart - H₃ Substrate 3 from heart - HB₁ Substrate 1 from heart blood - HB₂ Substrate 2 from heart blood - PC-H₁ H₁ cleaved from protein-carrier - PC-H₂ H₂ cleaved from protein-carrier - PC-H₃ H₃ cleaved from protein-carrier - PC-CC Coronaroconstrictory substance cleaved from protein-carrier - GPG Gomori-positive granules - MLC Mast-like cells     

Synthesis of symmetric and asymmetric diamides of citric acid and amino acids

Summary A convenient method for the synthesis of symmetric and asymmetric diamides of amino acids including DOPA and citric acid from 2-tert-butyl-1,3-di(N-hydroxysuccinimidyl)citrate and 1-tert-butyl-2,3-di(N-hydroxysuccinimidyl)citrate is described.Abbreviations AcOtBu tert-butyl acetate - i-Bu iso-butyl - tBu tert-butyl - Bzl benzyl - p-OH-Bzl p-hydroxybenzyl - m,p-(OH)₂-Bzl m,p-dihydroxybenzyl - DCCI dicyclohexylcarbodiimide - Et ethyl - Me methyl - Su succinimidyl - SuOH N-hydroxysuccinimide - Ph phenyl     

The ultrastructure of the marine gastrotrichTurbanella cornuta Remane (Macrodasyoidea) and its functional and phylogenetical importance

Summary The organization of marine gastrotrichs (Macrodasyoidea) is reviewed by ultrastructural analysis of one representative,Turbanella cornuta Remane, and the fine structure of tissues and cells is described. Turbanella cornuta has a mono-layeredcellular epidermis rich withsensory hairs, epidermal bodies, isolatedepidermal glands, glandular adhesive organs belonging to a duo-gland type, andventral ciliated epidermal cells of the multiciliated type. The voluminous neuropil of thebrain consists of a circular commissure which sends out four anterior and posterior longitudinal headnerves. The posterior ones unite on each side to one single longitudinal nerve of the periphery which is occupied with single peripheral neurons and has thin commissures that make it anorthogon. The position and the structure of the neurons indicate their sensitive, associative, motoric, and neurosecretory functions. The different forms of synapses give first hints to neuronal connections within gastrotrichs. There is a big cellularglia around the brain commissure and a small cellular glia within the brain neurons. In between the cross-striated muscle fibrils of thepharyngeal wall there are also nerves and sensory hairs.TheY-organ lies in the interior of the lateral body cavities, which are delimited by an outer musculature of the body wall and an inner musculature of the intestinal tract. In the pharyngeal region, theY-organ fills the body cavities completely and, in the intestinal region, it covers thegonads, which also lie in the lateral body cavities, dorsally. The testicles lie separately in front of the paired ovaries. Single states of oogenesis could be identified as oogonia, and young and old oocytes. There is a paired gland organ in front of the dorsomedian ovary which may produce a mucous cover for the egg.Theintestinal tract is adapted to mechanical stress by a myoepithelium in the pharyngeal region, by various interdigitations, and by narrow intercellular gaps with hemidesmosomal adhesions to the basement membrane. The majority of the resorbing intestinal cells have a high seam of microvilli and contain various numbers of lysosomes. In addition, there are some secerning cells without microvilli, but with a centrically arranged ER and with big secretion granules in the dorsomedian sector.The ultrastructure affirms a close correlation between the conditions of life in the interstitium and structural adaptations, such as may be observed in single structures of the body wall, the y-organ, the intestinal tract and, in some respect, even in the nervous system and in the formerly researched musculature and spermatohistogenesis. On the other hand, for the construction of the glandular adhesive organs, the nervous system, and the formerly investigated body cavities, a phylogenetical relevance is discussed. Thereafter, gastrotrichs have more primitive characters than the closely related nematodes.Abbreviations a sensory hair cells - am ampoule - at outleading tube - b basement membrane - bb basal body - c cilium - cr rootlet of the cilium - cu cuticle - cw cell wall - d d-cells of the brain - de desmosomes - e e-cells of the brain - eb epidermal bodies - ee ripe egg in the dorsomedian ovary - ep epidermis - er endoplasmatic reticulum - ev ventral ciliated epidermal cells - f f-cells of the brain - fr fibrillar structure - g gland cell - ge germ epithelium - gl₍₁₊₂₎ small and big cellular glia of the br - go Golgi-apparatus - gp genital pore - h h-cells of the brain - hf lateral adhesive tubules - hfp posterior adhesive tubules - i intestine - il intestinal lumen - 1 lumen of the organ - li lipid granules - ly lysosomes - m mitochondrium - mb multivesicular body - mc circular musculature - mi microvilli - ml longitudinal musculature - mo mouth opening - mt microtubules - mpl longitudinal muscle fibers of the pharyngeal wall - mpr radial muscle fibers of the pharyngeal wall - n nucleus - nb brain neurons - nc brain commissure - nf nerve fibers - nl lateral headnerve - nm nuclear membrane - nn nucleolus - nv ventrolateral headnerve - nz peripheric neuron - ncp peripheric nerve commissure - nvp longitudinal peripheric nerve - o lateral ovary - oc oocyte - oo oogonium - ow wall cells of the ovary - p secretory pore - ph pharynx - po palpar organ - phb pharyngeal bulbs - phl pharyngeal lumen - phn nerve plexus of the pharynx wall - sa anterior sense organ - sg secretory granules - sh sensory hair cell - sp posterior sense organ - st supporting stick - su supporting cell - sv synaptic vesicles - sy synaptic gap - t testicles - tl testicular lumen - tw wall cells of the testicles and the vas deferens - v ventral - va vacuoles - vd vas deferens - vs vesicles - y y-organ - yc anterior commissure of the y-organ - z yolk granules     

Fine structure and formation of eggshells in marine Gastrotricha

Summary The fine structure of the gastrotrich eggshell in the hermaphroditic species Turbanella ocellata (Hummon 1974) and the parthenogenetic species Aspidiophorus sp. is described using transmission electron microscopy. The presented evidence strongly suggests that the shell is produced by the egg itself prior to oviposition in both species. The layed egg in Aspidiophorus sp. is provided with a special attachment stalk that is also preformed in the mother animal. Freshly layed eggs of T. ocellata are adhesive all around their surface and lack any specialized structures for attachment. Formation of the spiny eggshell of Aspidiophorus sp. appears to begin with a sudden release of special vesicles containing the preformed spines of the outer eggshell covering. Additional material appears to be secreted by the egg in a more gradual process after the initial vesicle release. The formation of the two fibrous layers in the eggshell of T. ocellata is less well understood and deposition of eggshell material could be seen either as a continuous process or as two separate steps, similar to the events observed for Aspidiophorus sp. For T. ocellata, Tetranchyroderma sp. and Aspidiophorus sp. it is demonstrated that formation of the cuticle occurs as an independent process from that of eggshell formation. This is significantly different from the basic mode of cuticle formation in the annelid line of evolution. The paper argues further that the data support earlier claims of a pronounced difference between the Gastrotricha-Macrodasyida and the Gastrotricha-Paucitubulatina and agree well with the postulated ties of the Gastrotricha and Nematoda. The phylogenetic importance of the eggshell fine-structure is discussed in the framework of present theories on aschelminth phylogeny.Abbreviations cus cuticular spines - cut cuticle - cov coated vesicles - cv cup-shaped vesicles - dp dense particles - ep epidermis - emb embryo - erl lacunae of smooth ER - fgb fibrous and granular bodies - fl fibrous layer - ga Golgi apparatus - gc gut cell - gv Golgi vesicles - im intercellular matrix - isp intercellular space - isl inner shell layer - ld lipid droplet - mdb medium-dense bodies - mvb multivesicular bodies - oc oocyte - od oviduct - osl outer shell layer - o egg - sv spiny vesicles - sh eggshell - st egg-stalk - sl spiny layer - sub substrate - trm trilaminate membrane - yb yolk bodies - yg yolk granule - yoc young oocyte This work was supported by NSF Grant # GB-42211 to R.M. Rieger     

Fibulin-4 and fibulin-5 in elastogenesis and beyond: Insights from mouse and human studies

The fibulin family of extracellular matrix/matricellular proteins is composed of long fibulins (fibulin-1, -2, -6) and short fibulins (fibulin-3, -4, -5, -7) and is involved in protein–protein interaction with the components of basement membrane and extracellular matrix proteins. Fibulin-1, -2, -3, -4, and -5 bind the monomeric form of elastin (tropoelastin) in vitro and fibulin-2, -3, -4, and -5 are shown to be involved in various aspects of elastic fiber development in vivo. In particular, fibulin-4 and -5 are critical molecules for elastic fiber assembly and play a non-redundant role during elastic fiber formation. Despite manifestation of systemic elastic fiber defects in all elastogenic tissues, fibulin-5 null (Fbln5^−/−) mice have a normal lifespan. In contrast, fibulin-4 null (Fbln4^−/−) mice die during the perinatal period due to rupture of aortic aneurysms, indicating differential functions of fibulin-4 and fibulin-5 in normal development. In this review, we will update biochemical characterization of fibulin-4 and fibulin-5 and discuss their roles in elastogenesis and outside of elastogenesis based on knowledge obtained from loss-of-function studies in mouse and in human patients with FBLN4 or FBLN5 mutations. Finally, we will evaluate therapeutic options for matrix-related diseases.     

Syntheses and Herbicidai Activities of Phenoxypyrimidines and Phenoxytriazines

Series of phenoxypyrimidines and phenoxytriazines were prepared to be evaluated as herbicides. Among them, 2-(2,6-dichlorophenoxy)-pyrimidine (XV), 2-phenoxy-4,6-dimethyl- pyrimidine (XVII), 2-(3-methyl-4-chlorophenoxy)-4,6-bis(ethylamino)-5-triazine (LIV), 2-(2,4-dichlorophenoxy)-4,6-bis(ethylamino)-s-triazine (LVIII), and 2-(2,6-dichlorophenoxy)-4,6-bis(ethylamino)-s-triazine (LX) showed high pre-emergent herbicidai activity to radish. On the other hand, 2-chloro-4-(2,6-dichlorophenoxy)-6-methylpyrimidine (XXX) revealed high efficiency to millet. Some structure-activity relationship is discussed.     

Calcium exchanges in Anodonta cygnea: barriers and driving gradients

Electrical potential differences between the haemolymph and the extrapallial fluid, and between the haemolymph and the mantle cavity fluid, and ionic concentrations of calcium in the haemolymph and in extrapallial fluid were measured in vivo in Anodonta cygnea. The electrochemical potential of ionic calcium in the haemolymph is clearly above the electrochemical potential of ionic calcium in the environment and is very nearly in equilibrium with that of the extrapallial fluid. Simultaneous measurements of carbon dioxide partial pressure and pH in the extrapallial fluid showed that in this compartment ionic calcium is clearly above saturation. It is proposed that calcium deposition is regulated through the secretion of the organic matrix and by controlling the pH and the carbon dioxide partial pressure of the extrapallial fluid. An estimation of the minimum positive balance of calcium required to sustain shell growth together with the electrophysiological characterization of the mantle cavity epithelium showed that this tissue is not the route of entry of calcium into the animal.Abbreviations BW body weight - DW dry weight - E_EPF-S chemical potential difference - EPF extrapallial fluid - G_tot total conductance - I_sc short-circuit current - K_sp solubility product - MCE mantle cavity epithelium - MCF mantle cavity fluid - OME outer mantle epithelium - PCO₂ partial pressure of carbon dioxide - PVC Poly(vinyl chloride) - S shell - SEM standard error of mean - V _ic intracellular electrical potential - V _oc open-circuit voltage     

Chemical evolution and the origin of life

This bibliography is the seventeenth annual supplement to the comprehensive bibliography on the same subject which was published in Space Life Sci. 2(1970), 225-295; 3(1972), 293-304; 4(1973), 309-329 and in Origins of Life 5(1974), 505-527; 6(1975), 285-300; 7(1976), 75-85; 8(1977), 59-66; 9(1978), 67-74; 10(1980), 69-87; 10(1980), 379-404; 11(1981), 273-288; 12(1982), 93-118; 13(1983), 61-80; 15(1984), 55-69; 17(1987), 171-184; 17(1987), 185-206.     

Bacterial assimilation of d- and l-2-chloropropionates and occurrence of a new dehalogenase

The occurrence of a new bacterial dehalogenase acting on both the optical isomers of 2-halogenated alkanoic acids was demonstrated. When the haloalkanoic acid-utilizing bacteria were screened in a medium containing dl-2-chloropropionate as a sole carbon source, two types of bacteria were isolated: (1) a few strains utilizing both d- and l-isomers of 2-chloropropionate and (2) strains utilizing only the l-isomer. A dehalogenating enzyme was obtained from the cells of Pseudomonas sp. which is able to utilize both isomers. The crude enzyme catalyzed the dehalogenation of d- and l-2-chloropropionates to yield l- and d-isomers of lactate, respectively. The enzyme showed the same pH optimum and heat inactivation rate for the d- and l-isomers. Apparent K _m values for d- and l-2-chloropropionates were 4.5 and 1.0 mM, respectively. The enzyme acted specifically on 2-haloalkanoic acids. Activity staining of disc-gels electrophoresed witg the crude enzyme preparation showed that the dehalogenation of d- and l-2-chloropropionates, monochloroacetate, dichloroacetate, 2,2-dichloropropionate, and dl-2-chlorobutyrate is due to a single protein.Abbreviations MCA monochloroacetic acid - DCA dichloroacetic acid - TCA trichloroacetic acid - 2 MCPA 2-monochloropropionic acid - 22 DCPA 2,2-dichloropropionic acid - 3 MCPA 3-monochloropropionic acid - 2 MCBA 2-monochlorobutyric acid - 3 MCBA 3-monochlorobutyric acid - 4 MCBA 4-monochlorobutyric acid     

Anatomy and ultrastructure of ventral pharyngeal organs and their phylogenetic importance in Polychaeta (Annelida)

Summary A comparative anatomical and ultrastructural study of ventral pharyngeal organs (pharyngeal bulbs) was carried out in two species of the Dinophilidae: Dinophilus gyrociliatus and Trilobodrilus axi. Special attention was paid to the fine structure of the stomodeal epithelium, cuticle, glands, muscles, and myoepithelial junctions. The differences between the species are very slight. The pharyngeal organ of the Dinophilidae is characterized by the following features: solid muscle bulbus made up of muscle cells only, bulbus muscle cells with two myofilament systems crossing at an angle of about 90°, gap junctions between these muscle cells, bulbus projects into a pharyngeal sac and bears rostrally a specific epithelium and cuticle, no bulbus glands, no investing (= sagittal) muscles, specific cuticle ultrastructure, cilia of ascending oesophagus with asymmetric tips, specific structure and position of salivary gland openings. The phylogenetic importance of these structures is discussed. Some of these characters are clearly autapomorphic features of the Dinophilidae and no common derived structures to other families with a ventral pharyngeal organ are present. Therefore, it is most likely that the dinophilid pharyngeal organ evolved independently. These findings do not agree with the hypothesis of the unity of the archiannelid families (Polygordiidae, Protodrilidae, Saccocirridae, Nerillidae, Dinophilidae, and Diurodrilidae) established on the basis of an assumed structural similarity of their ventral pharyngeal organs.Abbreviations bb basal body - bep bulbus epithelium - bl basal lamina - bm bulbus muscle - c cilium - cc coelenchyme cell - cm circular muscle - cr caudal rootlet - cu cuticle - dblm dorsal bulbus longitudinal muscle - dlm dorsal longitudinal muscle - dsn dorsal stomatogastric nerve - dy dyad - el electron-dense layer - fl fibrous layer - fi filaments - g Golgi apparatus - gl gland cell - hv homogeneous vesicle - l lipid droplet - la external lamina - lal lamellar layer - ll lower lip - lm longitudinal muscle - ly lysosome - m mitochondrion - mo mouth opening - mt microtubule - mv microvillus - mvp microvillar process - n nucleus - nu nucleolus - oes oesophagus - pcom preoral commissure - phf pharyngeal fold - phl pharyngeal lumen - phs pharyngeal sac - pms peripheral myofilament system - r rootletlike structure - rer rough endoplasmic reticulum - rr rostral rootlet - s sarcoplasmic reticulum - sc salivary canal - scom suboesophageal commissure - sd septate desmosome - ser smooth endoplasmic reticulum - sg secretory granule - sgl salivary gland - sn stomatogastric nerve - st stomach - step stomodeal epithelium - tep transitional epithelium - tf tonofilaments - va vacuole - vlm ventral longitudinal muscle - vsn ventral stomatogastric nerve - z z-element - za zonula adherens     

Ca2+ transport and chemoreception in Paramecium

Intracellular Ca²⁺ levels in Paramecium must be tightly controlled, yet little is understood about the mechanisms of control. We describe here indirect evidence that a phosphoenzyme intermediate is the calmodulin-regulated plasma membrane Ca²⁺ pump and that a Ca²⁺-ATPase activity in pellicles (the complex of cell body surface membranes) is the enzyme correlate of the plasma membrane pump protein. A change in Ca²⁺ pump activity has been implicated in the chemoresponse of paramecia to some attractant stimuli. Indirect support for this is demonstrated using mutants with different modifications of calmodulin to correlate defects in chemoresponse with altered Ca²⁺ homeostasis and pump activity.Abbreviations EGTA ethyleneglycol tetra-acetate - ER endoplasmic reticulum - IBMX isobutyl methylxanthine - I _che index of chemokinesis - Mops 3-[N-morpholino] propanesulfonic acid - PEI phosphoenzyme intermediate - STEN sucrose, TRIS, EDTA, sodium chloride - TCA trichloroacetic acid - TRIS tris[hydroxymethyl] aminomethane     

High and low potential states of the chloroplast cytochromeb-559 and thermodynamic control of non-cyclic electron transport

Most of the chloroplastb-559 is high potential at neutral pH as defined by hydroquinone reducibility. FCCP^* (20 M) and antimycin A (50 M) convert high potentialb-559 to a low potential state which can be reduced by ascorbate but not hydroquinone. The low and high potential states of cytochromeb-559 are different forms of the same cytochrome.Three lines of evidence indicate that the cytb-559 oxidized by photosystem I is low potential: (1) theb-559 photooxidized by far-red light in the presence of FCCP (3 M) is low potentialb-559; (2) the amplitude of theb-559 oxidation by far-red light and the amount of low potentialb-559 present in the dark have the same general dependence on pH; (3) inhibitor studies show that plastoquinone mediates the oxidation of cytb-559 by PS I.The well-known stimulation ofb-559 oxidation by far-red light in the presence of FCCP is attributed to FCCP-facilitated photoconversion of high potentialb-559 to a low potential form.It is concluded that if cytb-559 is oxidized by system I light, then it is a low potential form (E _m7+80 mV) which is oxidized. It is not proven, however, that a significant amount of cytb-559 is oxidized by PS I under coupled or physiological conditions.Possible thermodynamic regulation of non-cyclic electron flow involving the distribution between high and low potential forms of cytb-559 is discussed.     

Phytochrome and internode elongation in Chenopodium polyspermum L. the light fluence rate during the day and the end-of-day effect

The elongation of the fourth internode of fully green Chenopodium polyspermum L. is strongly stimulated by far-red light (FR) given at the end of the day. The end-of-day effect is more important when the plants had been cultivated for several days with a main light period of 140 Wm^-2 than with a main light period of 85 Wm^-2. There exists a quantitative relationship between the FR end-of-day effect mediated by phytochrome and the value of the light fluence during the day.Abbreviations D darkness - FR far-red light - HWL white light at 140 Wm^-2 - LWL white light at 85 Wm^-2 - PAR photosynthetically active radiation - R red light - WL white light     

In Vitro and In Vivo Laboratory Evaluation of Cephaloglycin and Cephaloridine

Two new antibiotics, structurally related to cephalothin, have been given the generic names cephaloglycin and cephaloridine. Cephaloglycin is the dipolar ion of 7-(d-α-aminophenylacetamido)-cephalosporanic acid. Cephaloridine is 7-[α-(2-thiophene)acetamido]-3-(1-pyridylmethyl)-3-cephem-4-carboxylic acid betaine. These new compounds were evaluated simultaneously. The broad spectrum of activity observed in vitro and in vivo with both antibiotics, the good oral absorption obtained with cephaloglycin, and the stability of cephaloridine are emphasized. The data suggest that both antibiotics merit clinical trial in humans.     

Evolutionary and developmental aspects of phalangeal formula variation in pig-nose and soft-shelled turtles (Carettochelyidae and Trionychidae)

In order to examine the evolution of the phalangeal formula in a diverse clade of turtles, including hyperphalangy as a rare condition in this group, we studied 210 specimens representing all extant genera of Trionychidae and their sister taxon, Carettochelyidae. Both groups consist of highly aquatic species with elongated autopods that are either paddle-like (Trionychidae) or transformed to flippers (Carettochelyidae). Phalangeal formulae were obtained mostly by radiographs of alcohol-preserved or dry specimens, as well as by direct counts from skeletons. All trionychids and Carettochelys are pentadactylous, but their phalangeal formulae differ. Carettochelys exhibits the turtle-plesiomorphic state (manus and pes: 2-3-3-3-3), with no variation in adults. Trionychids exhibit intraspecific variation, ranging from 2-3-3-3-2 to 2-3-3-6-5 for the manus, and from 2-3-3-3-2 to 2-3-3-5-3 for the pes. The extant Carettochelys as well as the Middle Eocene Allaeochelys crassesculpta are characterized by an elongation of phalanges, whereas trionychids consistently have shorter phalanges. All trionychid genera exhibit some degree of hyperphalangy in digits IV and V, in both the manus and pes. Phalanges of the clawed digits I–III are very robust compared to phalanges of the non-clawed digits IV and V. The latter contribute significantly to the enlargement of the paddle by their additional phalanges. We hypothesize that this phalangeal pattern is coupled with prolongation of growth processes in the non-clawed digits. The differences in autopod morphology between carettochelyids and trionychids reflect different locomotor patterns related to different natural histories (elongated flippers for high-speed escape in the mainly herbivorous Carettochelys; broad paddles for rapid turns during hunting in the mainly carnivorous trionychids). The autopod of Pelodiscus sinensis is proposed as an experimental model to examine the developmental basis of adult autopod variation.     

Interkingdom Complementation Reveals Structural Conservation and Functional Divergence of 14-3-3 Proteins

The 14-3-3s are small acidic cytosolic proteins that interact with multiple clients and participate in essential cellular functions in all eukaryotes. Available structural and functional information about 14-3-3s is largely derived from higher eukaryotes, which contain multiple members of this protein family suggesting functional specialization. The exceptional sequence conservation among 14-3-3 family members from diverse species suggests a common ancestor for 14-3-3s, proposed to have been similar to modern 14-3-3ε isoforms. Structural features of the sole family member from the protozoan Giardia duodenalis (g14-3-3), are consistent with this hypothesis, but whether g14-3-3 is functionally homologous to the epsilon isoforms is unknown. We use inter-kingdom reciprocal functional complementation and biochemical methods to determine whether g14-3-3 is structurally and functionally homologous with members of the two 14-3-3 conservation groups of the metazoan Drosophila melanogaster. Our results indicate that although g14-3-3 is structurally homologous to D14-3-3ε, functionally it diverges presenting characteristics of other 14-3-3s. Given the basal position of Giardia in eukaryotic evolution, this finding is consistent with the hypothesis that 14-3-3ε isoforms are ancestral to other family members.     

RNase MRP and rRNA processing

RNase MRP is a ribonucleoprotein enzyme with a structure similar to RNase P. It is required for normal processing of precursor rRNA, cleaving it in the Internal Transcribed Spacer 1. Abbreviations: RNase MRP RNase for mitochondrial RNA processing; also involved in pre-rRNA processing; RNase P - RNase for pre-tRNA processing; snoRNA - small nucleolar RNA; RNP - RNA-protein particle; snoRNP - small nucleolar RNA-protein particle.