Linkage between the loci for the Lp(a) lipoprotein (LP) and plasminogen (PLG)

Summary A locus, LP, that determines quantitative variation of Lp(a) lipoprotein phenotypes is linked to the plasminogen (PLG) locus (peak lod score =12.73). This linkage relationship assigns a locus with alleles that have an affect on risk for coronary artery disease to the long arm of chromosome 6.     

Structural requirements of echistatin for the recognition of alpha(v)beta(3) and alpha(5)beta(1) integrins

There are key differences between the amino acid residues of the RGD loops and the C termini of echistatin, a potent antagonist of alpha(IIb)beta(3), alpha(v)beta(3) and alpha(5)beta(1), and eristostatin, a similar disintegrin selectively inhibiting alpha(IIb)beta(3). In order to identify echistatin motifs required for selective recognition of alpha(v)beta(3) and alpha(5)beta(1) integrins, we expressed recombinant echistatin, eristostatin, and 15 hybrid molecules. We tested them for their ability to inhibit adhesion of different cell lines to fibronectin and von Willebrand factor and to express ligand-induced binding site epitope. The results showed that Asp(27) and Met(28) support recognition of both alpha(v)beta(3) and alpha(5)beta(1). Replacement of Met(28) with Asn completely abolished echistatin's ability to recognize each of the integrins, while replacement of Met(28) with Leu selectively decreased echistatin's ability to recognize alpha(5)beta(1) only. Eristostatin in which C-terminal WNG sequence was substituted with HKGPAT exhibited new activity with alpha(5)beta(1), which was 10-20-fold higher than that of wild type eristostatin. A hypothesis is proposed that the C terminus of echistatin interacts with separate sites on beta(1) and beta(3) integrin molecules.     

Evidence for a differential functional regulation of the two beta(3)-integrins alpha(V)beta(3) and alpha(IIb)beta(3)

The functional regulation of integrins is a major determinant of cell adhesion, migration and tissue maintenance. The binding of cytoskeletal proteins to various sites of integrin cytoplasmic domains is a key mechanism of this functional regulation. Expression of recombinant integrin alpha(IIb)beta(3) and alpha(M)beta(2) lacking the GFFKR-region in CHO cells results in constitutively activated integrins. In contrast, CHO cells stably expressing either a GFFKR-deleted alpha(V(del))beta(3) or a FF to AA-substituted alpha(V(AA))beta(3) do not reveal a constitutively activated integrin. Adhesion to immobilized fibrinogen is strongly impaired in alpha(V(del))beta(3) or alpha(V(AA))beta(3)-expressing cells, whereas it is not impaired in alpha(IIb)beta(3) and alpha(M)beta(2), both lacking the GFFKR-region. In a parallel plate flow chamber assay, alpha(V)beta(3)-expressing cells adhere firmly to fibrinogen and spread even at shear rates of 15 to 20 dyn/cm(2), whereas alpha(V(del))beta(3) or alpha(V(AA))beta(3) cells are detached at 15 dyn/cm(2). Actin stress fiber formation and focal adhesion plaques containing alpha(V)beta(3) are observed in alpha(V)beta(3) cells but not in alpha(V(del))beta(3) or alpha(V(AA))beta(3)-expressing cells. As an additional manifestation of impaired outside-in signaling, phosphorylation of pp125(FAK) was reduced in these cells. In summary, we report that the GFFKR-region of the alpha(V)-cytoplasmic domain and in particular two phenylalanines are essential for integrin alpha(V)beta(3) function, especially for outside-in signaling. Our results suggest that the two beta(3)-integrins alpha(IIb)beta(3) and alpha(V)beta(3) are differentially regulated via their GFFKR-region.     

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

Abstract

Infrared spectroscopy was used to study hydrated double-helical poly(dG-dC) complexed with varying amounts of mercury (II). For one Hg(II) per ten nucleotide residues (r = 0.1), the B structure was stabilized and the B* structure was absent at high hydration. The Z structure did not form as hydration was reduced. For r = 0.2, the B and Z structures coexisted at high hydration and the transition to total Z structure was broad as hydration was reduced. Hg(II) was bound exclusively to the guanine residues probably at N 3 orN7forr < 0.25. The cytosine residue did not protonate (at N3) as Hg(II) was bound to guanine. The addition of NaCl together with Hg(II) reduced the binding of Hg(II), stabilized the B structure at the highest hydration and caused a sharp transition between the B and Z structures as hydration was lowered. Hydration with D,0 stabilized the Z structure for poly(dG-dC) complexed with HgCl₂.     

Structural forms and transitions for the complex of mercury(II) with poly(dG-dC)

Infrared spectroscopy was used to study hydrated double-helical poly(dG-dC) complexed with varying amounts of mercury(II). For one Hg(II) per ten nucleotide residues (r = 0.1), the B structure was stabilized and the B* structure was absent at high hydration. The Z structure did not form as hydration was reduced. For r = 0.2, the B and Z structures coexisted at high hydration and the transition to total Z structure was broad as hydration was reduced. Hg(II) was bound exclusively to the guanine residues probably at N3 or N7 for r less than or equal to 0.25. The cytosine residue did not protonate (at N3) as Hg(II) was bound to guanine. The addition of NaCl together with Hg(II) reduced the binding of Hg(II), stabilized the B structure at the highest hydration and caused a sharp transition between the B and Z structures as hydration was lowered. Hydration with D2O stabilized the Z structure for poly(dG-dC) complexed with HgCl2.     

Frontal glandular and sensory structures inNemertoderma (Nemertodermatida) andParatomella (Acoela): ultrastructure and phylogenetic implications for the monophyly of the Euplathelminthes (Plathelminthes)

Summary The ultrastructural organization of the frontal glandular and sensory structures in aNemertoderma species and in the acoelParatomella rubra is described. In both species, a frontal gland complex with an accumulation of different body wall glands and of ciliated sensory receptors exists at the anterior tip of a specimen. Such an organization can be hypothesized as a ground pattern characteristic of the Acoelomorpha. A frontal organ with a common apical pore of many necks of mucoid glands is known for most species of the Acoela; however, such an organ is not a basic feature either of this taxon or of the Acoelomorpha. This substantiates the hypotheses of a homology of the frontal glandular structures in the Acoelomorpha and the Rhabditophora and of the monophyly of the taxon Euplathelminthes. Within the Euplathelminthes, positional, morphological and histochemical differences of the frontal glands and the secretions exist between distinct taxa. These different organizations contribute to the phylogenetic systematization of the Plathelminthes, as shown in a diagram of the phylogenetic relationships among the basic closed descendent communities of this taxon.Abbreviations e,e ₁,e ₂ ellipsoid granules, types 1 and 2 - ep epidermis cell - f mucoid granules - gf mucoid gland neck - is intensively staining secretions - mit mitochondria - r rod-shaped rhabdoids - sr ₁ monociliated sensory receptors with vertical rootlet - sr ₂ monociliated sensory receptor with rhizomelike structure - sr ₃ monociliated sensory receptor with tubularlike structure - t target granules - tw terminal web     

Dominant (AFLP) and co‐dominant (microsatellite) markers for the kelp Postelsia palmaeformis (Laminariales)

To aid in understanding the structure, dispersal and genetic dynamics of their populations, we developed microsatellite and amplified fragment length polymorphism (AFLP) markers for the sea palm, Postelsia palmaeformis (Laminariales) for samples taken from nine sites in the area of Cape Flattery, Washington State, USA. We identified two AFLP primers that yielded 798 variable fragments and five microsatellite markers with three to seven alleles each. We also report patterns of allelic variation for four previously identified microsatellite markers in this species and several new alleles.     

Structural basis for stereoselectivity in the (R)- and (S)-hydroxypropylthioethanesulfonate dehydrogenases

Epoxide metabolism in Xanthobacter autotrophicus Py2 results in the conversion of epoxypropane to acetoacetate. Epoxide metabolism is initiated by the nucleophilic addition of coenzyme M to the (R)- and (S)-enantiomers of epoxypropane which forms the respective enantiomers of 2-hydroxypropyl-coenyme M. The (R)- and (S)-enantiomers of 2-hydroxypropyl coenzyme are oxidized to the achiral product 2-ketopropyl-CoM by two stereoselective dehydrogenases. The dehydrogenases catalyzing these reactions, termed (R)-hydroxypropyl-coenzyme M dehydrogenase (R-HPCDH) and (S)-hydroxypropyl-coenzyme M dehydrogenase (S-HPCDH), are NAD(+)-dependent enzymes belonging to the short chain dehydrogenase/reductase (SDR) family of enzymes. In this study, the crystal structure of R-HPCDH cocrystallized in the presence of (S)-hydroxypropyl-coenzyme M has been determined using X-ray diffraction methods and refined to 1.8 A resolution. The structure of R-HPCDH is tetrameric and stabilized by the interaction of the terminal carboxylates of each subunit with divalent metal ions. The structure of the presumed product-bound state reveals that binding interactions between the negatively charged oxygen atoms of the sulfonate moiety have striking similarities to sulfonate interactions observed in the previously determined structure of 2-ketopropyl-CoM oxidoreductase/carboxylase, highlighting the utility of coenzyme M as a carrier molecule in the pathway. The key elements of the aforementioned interactions are electrostatic interactions between the sulfonate oxygen atoms and two arginine residues (R152 and R196) of R-HPCDH. The comparison of the structure of R-HPCDH with a homology model of S-HPCDH provides a structural basis for a mechanism of substrate specificity in which the binding of the substrate sulfonate moiety at distinct sites on each stereoselective enzyme directs the orientation of the appropriate substrate enantiomer for hydride abstraction.     

New traps for the capture of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) (Diptera: Culicidae) eggs and adults

The control of arboviruses carried by Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) can be performed with tools that monitor and reduce the circulation of these vectors. Therefore, the efficiency of four types of traps in capturing A. aegypti and A. albopictus eggs and adults, with the biological product Vectobac WG, was evaluated in the field. For this, 20 traps were installed in two locations, which were in the South (Londrina, Paraná) and North (Manaus, Amazonas) Regions of Brazil, from March to April 2017 and January to February 2018, respectively. The UELtrap-E (standard trap) and UELtrap-EA traps captured A. aegypti and A. albopictus eggs: 1703/1866 eggs in Londrina, and 10268/2149 eggs in Manaus, respectively, and presented high ovitraps positivity index (OPI) values (averages: 100%/100% in Londrina, and 100%/96% in Manaus, respectively); and high egg density index (EDI) values (averages: 68/75 in Londrina, and 411/89 in Manaus, respectively), so they had statistically superior efficiency to that of the CRtrap-E and CRtrap-EA traps in both regions, that captured less eggs and adults: 96/69 eggs in Londrina, and 1091/510 eggs in Manaus, respectively. Also presented lower OPI values (averages: 28%/4% in Londrina, and 88%/60% in Manaus, respectively); and lower EDI values (averages: 10.5/9 in Londrina, and 47/30 in Manaus, respectively). The capture ratios of Aedes adults in the UELtrap-EA and CRtrap-EA traps in Londrina and Manaus were 53.3%/29.5% and 0%/9.8%, respectively. UELtrap-EA can be adopted as efficient tool for Aedes monitoring due to their high sensitivity, low cost and ease of use.     

A convenient method for the synthesis of amine-terminated poly(ethylene oxide) and poly(epsilon-caprolactone)

A convenient synthetic route to prepare amine-terminated poly(ethylene oxide) (PEO) and poly(epsilon-caprolactone) (PCL) was described. The strategy involved two-step reactions, the condensation of hydroxyl-terminated PEO and PCL with N-benzyloxycarbonyl amino acid followed by the catalytic hydrogenation under mild conditions. NMR and GPC measurements indicated that the reactions proceeded nearly quantitatively. Amine-terminated PEO thus prepared was used to initiate the polymerization of alpha-(N(epsilon)-benzyloxycarbonyl-L-lysine) N-carboxy anhydride [lys(Z)-NCA], and the results confirmed that the reactivity of the amino group was high.     

Morphological and other observations on Chonocephalus (Phoridae) and phylogenetic implications for the Cyclorrhapha (Diptera)

Chonocephalus blackithorum sp. nov . is described from Sulawesi. Biological observations on it and five other species are reported. In describing the female it proved necessary to re-evaluate the morphology of the female abdomen both in Chonocephalus and in the Phoridae as a whole. This adds to the growing evidence that the ground-plan of the Phoridae, and hence the Cyclorrhapha, is plesiomorphic with respect to the Empidoidea. The supposed affinity between these two groups is called into question and it is suggested that the Cyclorrhapha could even be an independent lineage from the Nematocera. The case for continuing to regard the Brachycera as monophyletic is also called into question by casting doubt on the rotation of the larval mandibles as a synapomorphy.     

Cloning and characterization of the gene for phytoene desaturase (Pds) from tomato (Lycopersicon esculentum)

The gene Pds encodes phytoene desaturase, a key enzyme in carotenoid biosynthesis that converts phytoene to -carotene. We have cloned and analyzed the genomic DNA sequence of Pds from tomato. In tomato Pds is comprised of 15 exons that, together with the introns occupy over 8 kb. A putative promoter sequence has been identified by comparison with the cDNA sequence of Pds. A consensus nucleotide sequence around intron splicing sites in tomato genes was determined by compiling data on 137 introns in 34 genes. This consensus sequence generally agrees with the consensus sequence of other higher plants with only minor differences that are unique to tomato.     

Spatio-temporal Distribution of Beskia aelops (Walker) (Diptera: Tachinidae) and its Potential for the Biocontrol of Oebalus poecilus (Dallas) (Hemiptera: Pentatomidae)

Oebalus poecilus is the most serious insect pest of rice in many South American countries. Presently, control of O. poecilus is wholly by the application of monocrotophos and most farmers use insecticides. Tachinid parasitoids are possible components in an IPM programme and their spatio-temporal dynamics were investigated for the first time over four crop seasons.