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991.
Washington Luiz da Silva Vieira Gindomar Gomes Santana Cristina Arzabe 《Biodiversity and Conservation》2009,18(1):55-66
Anuran reproductive activities in xeric environments are strongly influenced by local rainfall and temperatures. Anuran species
that inhabit the Caatinga biome in northeastern Brazil demonstrate numerous behavioral and reproductive strategies that avoid
or minimize the negative effects of elevated temperatures and scarce water resources on egg development. Among the various
anuran species found in the Caatinga region, members of the family Leptodactylidae demonstrate the greatest number of reproductive
modes adapted to a terrestrial life style while most of the Hylidae species are more susceptible to variations in water availability.
Laying eggs in foam nests is a common strategy among species that inhabit environments with open vegetation forms and water
resources that are restricted to only short periods during the year. Data concerning anuran communities in the localities
examined here indicated a greater diversity of reproductive modes in ponds with more diverse vegetation structures and longer
periods of water availability indicating that the deeper the temporary ponds (permitting a longer hydroperiod) the more diverse
will be the aquatic and bordering vegetation, and the richer will be the diversity of anuran species observed and the number
of reproductive modes encountered there. 相似文献
992.
Celso Teixeira Mendes‐Junior Aguinaldo Luiz Simões 《American journal of physical anthropology》2009,140(3):526-531
To study the genetic structure of the Tikúna tribe, four major Native American mitochondrial DNA (mtDNA) founder haplogroups were analyzed in 187 Amerindians from eight Tikúna villages located in the Brazilian Amazon. The central position of these villages in the continent makes them relevant for attempts to reconstruct population movements in South America. In this geographic region, there is particular concern regarding the genetic structure of the Tikúna tribe, formerly designated “enigmatic” due to its remarkable degree of intratribal homogeneity and the scarcity of private protein variants. In spite of its large population size and geographic distribution, the Tikúna tribe presents marked genetic and linguistic isolation. All individuals presented indigenous mtDNA haplogroups. An intratribal genetic heterogeneity pattern characterized by two highly homogeneous Tikúna groups that differ considerably from each other was observed. Such a finding was unexpected, since the Tikúna tribe is characterized by a social system that favors intratribal exogamy and patrilocality that would lead to a higher female migration rate and homogenization of the mtDNA gene pool. Demographic explosions and religious events, which significantly changed the sizes and compositions of many Tikúna villages, may be reflected in the genetic results presented here. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc. 相似文献
993.
Reduced-impact Logging has Little Effect on Temporal Activity of Frugivorous Bats (Chiroptera) in Lowland Amazonia 总被引:1,自引:0,他引:1
Steven J. Presley Michael R. Willig Luiz N. Saldanha Joseph M. Wunderle Jr . Ivan Castro-Arellano 《Biotropica》2009,41(3):369-378
Reduced-impact logging (RIL) represents a viable option for sustainable use of Neotropical lowland forests while minimizing negative effects on local biodiversity. Many Neotropical bats of the family Phyllostomidae provide ecosystem services associated with pollination and seed dispersal that promote the regeneration of disturbed areas; therefore, effects of RIL on these species is of particular concern. We determined patterns of temporal activity, degree of temporal overlap of activity, and dispersion in peaks of activity for seven abundant species of frugivorous bat in Tapajós National Forest, Pará, Brazil. In addition, we evaluated the effects of RIL at a harvest level of 18.7 m3 /ha and habitat physiognomy on temporal patterns of activity for these species. Bats were surveyed for four nights at each of 96 sites for a total sampling effort of 64,512 net-m-h. Sites were distributed among four experimental blocks, two blocks of unlogged forest and two blocks of forest subjected to RIL. Half of the sites in each management type were in forest gaps and half were in closed-canopy forest. In general, species exhibited similar patterns of activity, and greater than expected temporal overlap in activity among species. RIL and forest physiognomy had little effect on activity patterns of species. RIL in Amazonia removes fewer trees than do naturally occurring treefalls and such changes in habitat structure do not alter activity patterns of frugivorous bats. Evidence suggests that RIL does not have an appreciable adverse effect on frugivorous bats in Amazonia. 相似文献
994.
995.
Ipecac (Psychotria ipecacuanha) is a perennial, medicinal herb that grows in the understory of semi-deciduous tropical forests in the Neotropics. Ipecacs
present a widely disjunct distribution, with two of its three ranges occurring in Brazil. The Amazonian populations are at
least 1600 km from the nearest Atlantic populations. This work used ISSR markers to compare the genetic diversity and structure
of populations from the two Brazilian ranges. Lower genetic diversity in Amazon populations (P = 60.11%, Hs = 0.18) and higher
genetic diversity in Atlantic populations (P = 73.94%, Hs = 0.20) were detected. Differentiation between ranges were high
(θ
B = 0.6838, GST-B = 0.6665). AMOVA revealed that 65.3% of the total molecular variance can be attributed to regional differences between
the two ranges. Principal coordinate analyses and cluster analyses organized ipecacs at either individual or population level
into two exclusive groups that correspond each to one of the two disjunct ranges, without exception. The results do not support
a scenario that postulates human-mediated, long-distance dispersal events as a plausible origin for the distribution of the
Brazilian ipecacs, but indicate geographic isolation as a long-standing barrier to genetic exchange and connectivity among
populations from different ranges. Conservation implications are discussed. 相似文献
996.
Mario A. Izidoro Jorge A.N. Santos Vitor Oliveira Maria A. Juliano Luiz Juliano 《Archives of biochemistry and biophysics》2009,487(2):105-36521
We explored furin substrate requirements in addition to the motif R-X-K/R-R using synthetic fluorescent resonance energy transfer (FRET) decapeptides. These decapeptides were derived from furin cleavage sites in viral coat glycoproteins and human and bacterial protein precursors. The hydrolysis by furin of most substrate was activated by K+ ion, whereas kosmotropic anions of the Hofmeister series were inhibitors. The analysis of furin hydrolytic activity showed that its efficiency is highly dependent on the particular combinations of amino acids at different substrate positions. There is a clear interdependence of furin subsites that must be taken in account in determining its specificity and also for the design of inhibitors. However, clear preferences were detected for substrates with S at P1′, and V at P2′, at P3′ the amino acids D, S, L and A are almost equally frequent. In the non-prime subsites the best substrates presented S and H at P6; basic amino acids at P5; and no clear tendency at P3. Interestingly, two amino acid substitutions on the prime side of the peptide derived from H5N1 influenza hemagglutinin furin processing site highly improved its hydrolysis. These modifications are possible by single point mutations, suggesting a potential yield of a more infectious virus. 相似文献
997.
Valeria Castilho Onofrio Darci Moraes Barros-Battesti Marcelo Bahia Labruna João Luiz Horácio Faccini 《Systematic parasitology》2009,72(2):143-157
The current Brazilian Ixodes fauna is composed of the following eight species: I. amarali Fonseca, 1935; I. aragaoi Fonseca, 1935; I. auritulus Neumann, 1904; I. fuscipes Koch, 1844; I. loricatus Neumann, 1899; I. luciae Sénevet, 1940; I. paranaensis Barros-Battesti, Arzua, Pichorim &; Keirans, 2003; and I. schulzei Aragão &; Fonseca, 1951. Further studies are needed to establish the taxonomic status of I. serrafreirei Amorim, Gazeta, Bossi &; Linhares, 2003, a recently proposed species based solely on the nymphal stage. We present an up-to-date key to adults of the currently valid Brazilian species of Ixodes based on scanning electron microscopy. The relationships between Brazilian and other Neotropical Ixodes are also discussed. 相似文献
998.
Carlos Rodrigo Zárate‐ Bladés Vânia Luiza Deperon Bonato Eduardo Lani Volpe da Silveira Marina Oliveira e Paula Cristina Moraes Junta Paula Sandrin‐Garcia Ana Lúcia Fachin Stephano Spanó Mello Renato Sousa Cardoso Fábio Cícero de Sá Galetti Arlete Aparecida Martins Coelho‐Castelo Simone Gusmão Ramos Eduardo Antonio Donadi Elza Tiemi Sakamoto‐Hojo Geraldo Aleixo da Silva Passos Celio Lopes Silva 《The journal of gene medicine》2009,11(1):66-78
999.
Marcus Livio Varella Coelho Hilana Ceotto Danielle Jannuzzi Madureira Ingolf F. Nes Maria do Carmo de Freire Bastos 《Journal of microbiology (Seoul, Korea)》2009,47(3):327-336
Plasmid pRJ6 is the first known bacteriocinogenic mobilizable (Mob) plasmid of Staphylococcus aureus. Its Mob region is composed of four mob genes (mobCDAB) arranged as an operon, a genetic organization uncommon among S. aureus Mob plasmids. oriT
pRJ6 was detected in a region of 431 bp, positioned immediately upstream of mobC. This region, when cloned into pCN37, was able to confer mobilization to the re-combinant plasmid only in the presence of
pRJ6. The entire Mob region, including oriT
pRJ6, is much more similar to Mob regions from several coagulase-negative staphylococci plasmids, although some remarkable similarities
with S. aureus Mob plasmids can also be noted. These similarities include the presence within oriT
pRJ6 of the three mcb (MobC binding sites), firstly described in pC221 and pC223, an identical nick site also found in these same plasmids, and a nearly identical sra
pC223 site (sequence recognized by MobA). pRJ6 was successfully transferred to S. epidermidis by conjugation in the presence of the conjugative plasmid pGOl. Altogether these findings suggest that pRJ6 might have been
originally a coagulase-negative staphylococci plasmid that had been transferred successfully to S. aureus. 相似文献
1000.
Fabiana G. S. Pinto Ligia M. O. Chueire Ana Tereza R. Vasconcelos Marisa F. Nicolás Luiz G. P. Almeida Rangel C. Souza Pâmela Menna Fernando G. Barcellos Manuel Megías Mariangela Hungria 《Functional & integrative genomics》2009,9(2):263-270
Rhizobium tropici is representative of the diversity of tropical rhizobia, besides comprising strains very effective in fixing N2 in symbiosis with the common bean (Phaseolus vulgaris L.). The genome of a Brazilian commercial inoculant R. tropici strain (PRF 81, =SEMIA 4088), estimated at 7.85 Mb, was analyzed through a total of 9,026 shotgun reads, assembled in 1,668
phrap contigs, and covering ≈30% of the genome. Annotation identified 2,135 coding DNA sequences (CDS), and only 57.2% have
possible functions. The genome comprises a mosaic of genes, with CDS showing the highest similarities with 134 microorganisms,
none of which represents more than 19% of the CDS with putative known functions. The high saprophytic capacity of PRF 81 may
reside in a variety of genes related to transport, biodegradation of xenobiotics, defense, and secretion proteins, many of
which were reported for the first time in the present study. Novelty was also found in nodulation (nodG, a double nodIJ system, nodT, nolF, nolG) and capsular polysaccharide genes, showing stronger similarities with Sinorhizobium (=Ensifer) than with the main symbionts of the common bean—R. etli and R. leguminosarum—suggesting that the original host of R. tropici might be another tropical legume or emphasizing the highly promiscuous nature of this rhizobial species. 相似文献