Whither Latin America? Trends and challenges of science in Latin America

Science in Latin America has experienced vigorous growth in the past decade, as demonstrated by the fact that the Latin American share of the world's scientific publications increased from 1.8% in 1991-1995 to 3.4% in 1999-2003. Significant growth has also taken place in the numbers of PhDs in science and engineering (S&E) awarded in Latin American countries in recent years, including those in the natural sciences. Importantly, albeit at different rates, growth has been verified in almost all countries in the region, indicating a general effort to promote the development of S&E. In most research fields, however, the recognition or relative impact of Latin American science, as measured by the average number of citations received by published articles (CpP), is still below world averages and much lower than in developed nations. We show that average CpP values for a set of 34 representative developing and developed countries correlate significantly with gross expenditure in research and development (GERD), with gross domestic product (GDP) per capita and with the number of researchers per million inhabitants (RpM). Among those countries, Latin American nations present some of the lowest average values of CpP (<6), GERD (< or =1% of GDP) and RpM (<2,000). We also examined recent trends in scientific activity in Latin America, with focus on the natural sciences and on biochemistry and molecular biology (BMB). In terms of citation scores, publications in BMB compare favorably to those in other research fields within Latin America. At the same time, however, Latin American BMB is one of the areas for which relative impact--compared to developed nations or normalized to world averages--is lowest. These observations clearly indicate the need to establish effective policies to increase competitiveness in terms of the quality and international recognition of Latin American natural sciences in general, and BMB in particular, as opposed to merely increasing the absolute numbers of publications or the numbers of PhDs awarded in the region.     

IR and Raman study on the interactions of the 5′-GMP and 5′-CMP phosphate groups with Mg(II), Ca(II), Sr(II), Ba(II), Cr(III), Co(II), Cu(II), Zn(II), Cd(II), Al(III) and Ga(III)

The chief motive behind this research is the interest provoked by the presence of metal ions as necessary stabilizers of the negative charges of phosphate groups in nucleic acids. The effect that the presence of different metal ions produces on the band principally assigned to the nu(s) PO(3)(2-) mode has been studied using FT-IR and FT-Raman spectroscopy. The results obtained reveal the diagnostic capacity of these techniques in determining the type of metal ion interaction with respect to the mononucleotides that form DNA and RNA, providing a tool for improving the knowledge of the stabilizing or destabilizing effects of these ions on such macromolecules. The metal complexes of the ribonucleotides 5'-CMP and 5'-GMP with Mg(II), Ca(II), Sr(II), Ba(II), Cr(III), Co(II), Cu(II), Zn(II), Cd(II), Al(III) and Ga(III) were obtained in this study. After studying and analyzing the IR and Raman spectra of all these complexes and comparing them with the spectra of the corresponding disodium salts, it was verified that, independently of the type of nucleotide involved, the presence of the metal in the vicinity of the phosphate group produces an alteration in the aforementioned nu(s) PO(3)(2-) band. This effect is related to the type of interaction that the phosphate group has with the metal. Three components are observed: (1) one near 983-975 cm(-1) (detectable in IR and Raman), associated with phosphate groups in an electrostatic type of interaction with the metal ion, separated by two or more water molecules; (2) another near 989-985 cm(-1) (only in IR), associated with phosphate groups in indirect interaction through the water molecules of the coordination sphere of the metal ions; and (3) the IR and Raman bands near 1014-1001 cm(-1), which represent phosphate groups directly bonded to the metal ion. These results are supported by the behavior of 5'-CMP in aqueous solution in the presence of Mg(II) ions.     

Synthesis, Characterization and Antitumor Studies of Mn(II), Ni(II), Cu(II) and Zn(II) Complexes of N-Nicotinoyl-N′-o-Hydroxythiobenzhydrazide

A new ligand N-Nicotinoyl-N-o-hydroxythiobenzhydrazide (H₂Notbh) forms complexes [Mn(Notbh)(H₂O)], [M(Notbh)] [M=Ni(II) Cu(II) and Zn(II)] which were characterized by various physico-chemical techniques. All the metal complexes were observed to inhibit the growth of tumor in vitro, whereas, ligand did not. In vivo administration of these complexes resulted in prolongation of survival of tumor bearing mice. Tumor bearing mice administered with metal complexes showed reversal of tumor growth associated induction of apoptosis in lymphocytes. The paper discusses the possible mechanisms and therapeutic implication of the H₂Notbh and its metal complexes in tumor regression and tumor growth associated immunosuppression.     

Incidental finding of double minutes (DM), single minutes (SM), homogenously staining regions (HSR), premature chromosome condensation (PCC), and premature centromere division (PCD)?

The incidental finding of DM's, minutes, HSR's, PCC, and PCD in two completely unrelated cases--one is a prenatal diagnosis in a twin pregnancy complicated by hydramnios and feto-fetal exsanguination, the other is an adult Klinefelter patient--raises the question whether such findings are coincidental or whether there is a common denominator in such cases. Possible relationships between these phenomena and the observed cases are discussed.     

Interaction of Adenosine 5′-Triphosphate with Metal Ions X-ray Structure of Ternary Complexes Containing Mg(II), Ca(II), Mn(II), Co(II), ATP and 2,2′ -Dipyridylamine

Abstract

The X-ray structures of the isomorphous Mg²⁺, Ca²⁺, Mn²⁺ and Co²⁺ complexes of ATP have been determined. The metal ions are wrapped in hexa-coordination by the α, β and γ phosphate groups of two ATP molecules thus blocking the interaction of the metal ions with the adenine base. A second metal ion which is fully hydrated, M(H₂O)²⁺ ₆, is engaged in a strong hydrogen bond with the γ phosphate group of ATP and suggests a possible step in facilitating the cleavage between the β and γ phosphates in phosphoryl transfer reactions.     

Synthesis, characterization and antitumor studies of N-aroyl-N′-thioaroylhydrazines and their Co(II), Ni(II), Cu(II) and Zn(II) complexes

N-Salicyloyl-N-p-hydroxythiobenzohydrazide (H₂STPH) and N-benzoyl-N-thiobenzohydrazide (H₂BTBH) and their Co(II), Ni(II), Cu(II) and Zn(II) complexes were prepared and characterized by physicochemical studies. IR and NMR spectral studies imply dibasic tetradentate behaviour of the ligands bonding through `thiolato' sulfur, enolic oxygen and the two hydrazinic nitrogens in a polymeric fashion. The electronic spectra indicate [Ni(STPH)(H₂O)₂], [Co(STPH)(H₂O)₂] to be distorted octahedral while [Cu(BTBH)] has a square-planar geometry. In vitro antitumor results of the ligand and the complexes on P-815 (murine mastocytoma) and L-929 (murine fibroblast) indicate that these compounds show significant inhibition of ³H-thymidine and ³H-uridine incorporation in DNA and RNA, respectively, in these tumor cells at dose levels of 1, 2.5 and 5 g cm^–3. Antitumor studies suggest that [Cu(BTBH)] has significant dose dependent inhibitory effect on DNA synthesis. In vivo administration of [Cu(BTBH)] and [Ni(STPH)(H₂O)₂] resulted into prolongation of life span of Dalton's Lymphoma (DL) bearing mice.     

Subunit structure and higher order assembly of the hemocyanins of the Melongenidae family: Melongena corona (Gmelin), Busycon canaliculatum (Linné), B. carica (Gmelin), B. contrarium (Conrad), and B. spiratum (Lamarck)

1. The hemocyanins of the Melongenidae family of marine gastropods: Melongena corona, Busycon canaliculatum, B. carica, B. contrarium, and B. spiratum exist in solution as multi-decameric aggregates characterized by sedimentation coefficients of approximately 105 S, 130 S, 150 S, 170 S, and higher values, corresponding to di-, tri-, tetra-, penta-, and larger multi-decameric particles. 2. The hemocyanins of B. contrarium and B. carica seem to form the largest decameric aggregates with the tri- to penta-decamers respresenting the major constitutents. Scanning transmission electron microscopy (STEM), both of unstained, freeze-dried and negatively-stained specimens, shows the presence of discrete aggregates consisting of up to ten decameric units. 3. The particle masses as determined by STEM mass measurements for individual molecules gave integral multiples of from 4.2 x 10(6) to 4.4 x 10(6) daltons ranging from about 8.2 x 10(6) daltons for the typical di-decamer of B. canaliculatum hemocyanin to as high as about 39 x 10(6) and 43 x 10(6) for the nano-and deca-decamers of B. contrarium hemocyanin. 4. The appearance of the higher multi-decamers in both negatively-stained and freeze-dried specimens suggest that they are formed by the addition of decameric units to a single di-decameric unit "tail-wise" in both directions. The higher aggregates formed seem to terminate with a closed head or collar at both ends of the assembly.     

A capitosauroid from the Lower Triassic of South America (Sanga do Cabral Supersequence: Paraná Basin), its phylogenetic relationships and biostratigraphic implications

Surviving through the end-Permian mass extinction, stereospondyls reemerged reaching a widespread distribution during the Early Triassic. A well representative lineage of this clade, Capitosauroidea, became worldwide abundant from Early to Late Triassic, in which their first undoubtful representatives were recovered from Lower Triassic deposits. Here, we describe a new capitosauroid, Tomeia witecki gen. et sp. nov., from the Sanga do Cabral Supersequence (Paraná Basin). Although relatively incomplete, the material presents a particular combination of early and late-diverging capitosauroid characters. Supporting Tomeia witecki as a new capitosauroid, our phylogenetic analysis placed the taxon as part of a clade that comprises only Early Triassic capitosauroids, specifically as the sister-taxon of the madagascarian Edingerella madagascariensis and close to Watsonisuchus spp., from Australia, South Africa and Madagascar. The status of Tomeia witecki as a new capitosauroid from western Gondwana supports a continuous record of the Stereospondyl lineage, since their first appearance during the Middle Permian in this supercontinent. Additionally, the temporal range of the Sanga do Cabral Supersequence during the Early Triassic was specifically reinforced as Olenekian, mainly based on the overall faunal content previously reported to this unit, associated with the known temporal distribution from those taxa phylogenetically closer to Tomeia witecki.

http://zoobank.org/urn:lsid:zoobank.org:pub:7AA9F874-BED5-4A99-B098-B50656E706C1     

Frances Lawrence Parker (1906–2002), micropaleontologist and pioneer of paleoceanography

Frances L. Parker made important contributions to the knowledge of benthic and planktonic Foraminifera, both in respect to taxonomy and to biogeographic and stratigraphic distributions. Her work became part of the foundations of modern paleoceanography, which may be said to begin with the results of the Swedish Deep-Sea Expedition (R/V Alabatross, 1947–1948). Among her most significant works is a demonstration of warm-cold cycles in the Mediterranean, based on Albatross cores, a reorganization of the classification of recent planktonic foraminifers, and a study of lineages in planktonic foraminifers for the Late Cenozoic.     

Do tigers hunt during the day? Diel activity of the Asian tiger mosquito,Aedes albopictus (Diptera: Culicidae), in urban and suburban habitats of North America

BackgroundAedes (Stegomyia) albopictus (Skuse) impacts human outdoor activity because of its aggressive biting behavior, and as a major vector of mosquito-borne diseases, it is also of public health importance. Although most mosquito species exhibit crepuscular activity by primarily host seeking at dawn and dusk, Ae. albopictus has been traditionally characterized as a diurnal or day-biting mosquito. With the global expansion and increased involvement of Ae. albopictus in mosquito-borne diseases, it is imperative to elucidate the diel activity of this species, particularly in newly invaded areas.Methodology and principal findingsHuman sweep netting and carbon dioxide-baited rotator traps were used to evaluate the diel activity of Ae. albopictus in two study sites. Both trapping methods were used in New Jersey’s Mercer County, USA (temperate/urban), while only human sweep netting was used in Florida’s Volusia County, USA (subtropical/suburban). Human sweep netting was performed to determine adult mosquito activity at Sunrise, Solar Noon, Sunset, and Lunar Midnight. Because New Jersey is in a temperate area, diel activity was investigated during the early season (3–19 July), peak season (25 July-19 September), and late season (22 September- 22 October). Aedes albopictus showed the highest activity during peak and late seasons at Solar Noon (P < 0.05). At Sunrise and Sunset during the peak season, Ae. albopictus activity was similar. Lunar Midnight activity was significantly lower than Sunrise and Solar Noon (P < 0.05) but was similar to that of Sunset. In the late season, the highest activity was observed during Solar Noon while the least activity was observed during Sunrise and Lunar Midnight (P<0.05). Bottle rotator traps used in conjunction with the human sweep net technique exhibited similar results. Seasonal activity was not differentiated in Florida due to the consistent subtropical climate. The highest adult activity was observed at Sunrise using human sweep netting, but it was not significantly different from Solar Noon and Sunset. The lowest adult activity was observed at Lunar Midnight; however, it was not significantly different from Solar Noon and Sunset. These results provide evidence that the diel activity of Ae. albopictus, contrary to the common perception of its diurnal activity, is much more varied.Conclusion/SignificanceInvolvement of Ae. albopictus in the transmission of debilitating mosquito-borne pathogens such as chikungunya, dengue, and Zika virus, coupled with its affinity to thrive in human peridomestic environments, substantiates that our findings have global implications in areas where Ae. albopictus populations established. It also highlights the importance of behavioral studies of vector species which will not only help mosquito control professionals plan the timing of their control efforts but also provides empirical evidence against conventional wisdoms that may unjustly persist within public health stewards.     

Biotechnological production of arbutins (α- and β-arbutins), skin-lightening agents, and their derivatives

Arbutins (α- and β-arbutins) are glycosylated hydroquinones that are commercially used in the cosmetic industry. These compounds have an inhibitory function against tyrosinase, a critical enzyme for generating pigments, which leads to the prevention of melanin formation, resulting in a whitening effect on the skin. Although β-arbutin is found in various plants including bearberry, wheat, and pear, α-arbutin and other arbutin derivatives are synthesized by chemical and enzymatic methods. This article presents a mini-review of recent studies on the production of α-arbutin and other α- and β-arbutin derivatives via enzymatic bioconversion methods. In addition, the structures of α- and β-arbutin derivatives and their biological activities are discussed. The catalytic characteristics of various enzymes used in the biosynthesis of arbutin derivatives are also reviewed.     

Syntheses of dl-N-Demethylvariotinyl 2-Pyrrolidonide (dl-Demethylvariotin), 2-Piperidonide,and ε-Caprolactamide

The syntheses of three dl-demethylvariotins are described.     

Assignment of the rat genes coding for α1-antitrypsin (PI), phosphoenolpyruvate carboxykinase (PEPCK), alcohol dehydrogenase (ADH), and fructose-1, 6-bisphosphatase (FDP)

The chromosomal localization of four genes which are expressed mainly in the liver has been undertaken for the rat. Using a panel of hybrid clones segregating rat chromosomes, and Southern blot analysis, 1-AT (PI), PEPCK, ADH and FDP are assigned to rat Chromosomes (Chr) 6, 3, 2 and 17, respectively. Groups of synteny among rat, mouse and human species are discussed in relationship to the new assignments.     

Comparative genomics of duplicate γ-glutamyl transferase genes in teleosts: medaka (Oryzias latipes), stickleback (Gasterosteus aculeatus), green spotted pufferfish (Tetraodon nigroviridis), fugu (Takifugu rubripes), and zebrafish (Danio rerio)

The availability of multiple teleost (bony fish) genomes is providing unprecedented opportunities to understand the diversity and function of gene duplication events using comparative genomics. Here we examine multiple paralogous genes of γ-glutamyl transferase (GGT) in several distantly related teleost species including medaka, stickleback, green spotted pufferfish, fugu, and zebrafish. Through mining genome databases, we have identified multiple GGT orthologs. Duplicate (paralogous) GGT sequences for GGT1 (GGT1 a and b), GGTL1 (GGTL1 a and b), and GGTL3 (GGTL3 a and b) were identified for each species. Phylogenetic analysis suggests that GGTs are ancient proteins conserved across most metazoan phyla and those paralogous GGTs in teleosts likely arose from the serial 3R genome duplication events. A third GGTL1 gene (GGTL1c) was found in green spotted pufferfish; however, this gene is not present in medaka, stickleback, or fugu. Similarly, one or both paralogs of GGTL3 appear to have been lost in green spotted pufferfish, fugu, and zebrafish. Syntenic relationships were highly maintained between duplicated teleost chromosomes, among teleosts and across ray-finned (Actinopterygii) and lobe-finned (Sarcopterygii) species. To assess subfunction partitioning, six medaka GGT genes were cloned and assessed for developmental and tissue-specific expression. On the basis of these data, we propose a modification of the "duplication-degeneration-complementation" model of subfunction partitioning where quantitative differences rather than absolute differences in gene expression are observed between gene paralogs. Our results demonstrate that multiple GGT genes have been retained within teleost genomes. Questions remain, however, regarding the functional roles of multiple GGTs in these species.     

Paraconvexitermes acangapua (Isoptera: Termitidae,Nasutitermitinae), a new genus and new species of the so-called “small Neotropical soil-feeding nasutes” from South America

A new genus Paraconvexitermes is described, comprising Paraconvexitermes acangapua, new species, P. nigricornis (Holmgren) and P. junceus (Emerson), both previously in Convexitermes Holmgren. Now, Convexitermes comprises C. manni Emerson and C. convexifrons (Holmgren). The worker’s digestive tube of both genera along with those of Atlantitermes species allowed to get a better definition of these three genera. Illustrations on the digestive tube and mandibles of workers, soldier’s head, alate’s head and secondary reproductive female of the new genus and species are provided. The phylogenetic relationships with the other nasute genera are discussed along with the “soil feeding” concept.     

Stories and photographs of William A. Arnold (1904–2001), a pioneer of photosynthesis and a wonderful friend

William A. Arnold discovered many phenomena in photosynthesis. In 1932, together with Robert Emerson, he provided the first experimental data that led to the concept of a large antenna and a few reaction centers (photosynthetic unit); in 1935, he obtained the minimum quantum requirement of 8–10 for the evolution of one O₂ molecule; in 1951, together with Bernard L. Strehler, he discovered delayed fluorescence (also known as delayed light emission) in photosynthetic systems; and in 1956, together with Helen Sherwood, he discovered thermoluminescence in plants. He is also known for providing a solid-state picture of photosynthesis. Much has been written about him and his research, including many articles in a special issue of Photosynthesis Research (Govindjee et al. (eds.) 1996); and a biography of Arnold, by Govindjee and Srivastava (William Archibald Arnold (1904–2001), 2014), in the Biographical Memoirs of the US National Academy of Sciences, (Washington, DC). Our article here offers a glimpse into the everyday life, through stories and photographs, of this remarkable scientist.