Optical absorption of single-layer hexagonal boron nitride in the ultraviolet.

In this paper we theoretically describe the absorption of hexagonal boron nitride (hBN) single layer. We develop the necessary formalism and present an efficient method for solving the Wannier equation for excitons. We give predictions for the absorption of hBN on quartz and on graphite. We compare our predictions with recently published results (Elias et al 2019 Nat. Commun. 10 2639) for a monolayer of hBN on graphite. The spontaneous radiative lifetime of excitons in hBN is also computed. We argue that the optical properties of hBN in the ultraviolet are very useful for the study of peptides and other biomolecules.

Effect of the addition of IGF-I and vitamin E to stored boar semen.

The objective of this study was to evaluate the addition of IGF-I to pig insemination doses stored at 15°C, in conjunction with the addition of different amounts of vitamin E (α-tocopherol). Semen samples (n = 12) from four boars were treated by the addition of different concentrations of vitamin E, ranging up to 400 µg/ml. Immediately after processing and after the doses had been stored at 15°C for 24 or 72 h, samples were warmed at 37°C and 30 ng/ml of IGF-I was added. The assessments were made after 10 and 120 min of IGF-I addition. There was a minor effect of the vitamin E added before cooling and IGF-I added after storage on sperm quality. The addition of 400 µg/ml of vitamin E to diluted semen reduced (P < 0.01) the malondialdehyde (MDA) production in boar semen stored at 15°C for 72 h, regardless of the addition of IGF-I as additive during a 120 min incubation period at 37°C. In these conditions, IGF-I also reduced (P < 0.05) the MDA production in semen samples without addition of vitamin E. IGF-I in the presence of vitamin E reduced (P = 0.03) the glucose intake in freshly diluted boar semen samples before cooling. It was concluded that the addition of 400 µg/ml of vitamin E reduces the MDA production in boar semen stored at 15°C for 72 h, regardless of the presence of IGF-I additive. The addition of IGF-I in doses stored for 72 h with vitamin E ensures higher sperm motility after 120 min of incubation at 37°C.

First Report of Johnsongrass mosaic virus (JGMV) Infecting Pennisetum purpureum in Brazil.

Tropical grass and legume species used as pasture grasses for cattle feeding cover over 25% of the agricultural area in Brazil. In recent years, plants showing virus-like symptoms have been observed in the main pasture grass growing areas. Plants of Pennisetum purpureum line CNPGL 00211 showing typical virus mosaic symptoms on leaves and growth reduction were collected in Bahia State, Brazil. Flexuous elongated potyvirus-like particles were observed in the leaf-dip preparation of diseased plants by electron microscopy. In addition, the virus was mechanically transmitted using a standard procedure for potyviruses (4) and produced similar symptoms in inoculated P. purpureum plants. For further molecular identification, total RNA was extracted from frozen symptomatic leaves following the guanidine thiocyanate method (3). cDNA synthesis was performed using oligonucleotide, OligodT50M10 and PCR was carried out using Potyvirus degenerate primers PY11 (5'-GGNAAYAAYAGYGGNCARCC-3') (2) and M10 (5'-AAGCAGTGTTATCAACGCAGA-3'). The amplified fragments of the expected size (approximately 2 kb comprising part of the NIb protein gene, the entire coat protein [CP] gene, and the 3' nontranslated region) were separated using agarose gel electrophoresis, excised, and cloned into plasmid vector pGEMT-Easy (Promega) according to the manufacturer's instructions. Four selected clones were sequenced (Macrogen, South Korea). The sequenced 2.0-kb fragment (GenBank Accession No. KC333416) was compared with sequences available in GenBank and the highest nucleotide identity of 79% was observed with Johnsongrass mosaic virus (JGMV) isolated in Australia (4). According to the Potyvirus species demarcation convention based on CP identity (1), the virus isolate from P. purpureum belongs to the JGMV species. However, the amino acid sequence of the N-terminus of the CP of the Bahia isolate is distinct from JGMV sequences reported in GenBank. The phylogenetic analysis of the CP confirmed the difference since this Bahia isolate was located in a clearly distinct branch separate from all JGMV isolates. To our knowledge, this is the first report of a JGMV in Brazil infecting tropical grass in the main pasture areas. References: (1) M. J. Adams et al. Arch. Virol. 150: 459, 2005. (2) J. Chen et al. Arch. Virol. 146:757. 2001. (3) P. Chomczynski and N. Sacchi. Nature Protocols 1:581, 2006. (4) H. K. Laidlaw et al. Arch. Virol. 149:1633, 2004.

Produção de frutos para uso medicinal em Bromelia antiancatha (caraguatá): fundamentos para um extrastivismo sustentável / Fruit production for medicinal use in Bromelia antiacantha ("caraguatá"): foundations for sustainable extraction

Entre as várias espécies que têm sido utilizadas como fontes de subprodutos florestais estão a Bromelia antiacantha, espécie nativa da Mata Atlântica com grande potencial de uso com características alimentícias, ornamentais, industriais e farmacológicas. Os frutos da espécie são utilizados tradicionalmente no Planalto Norte Catarinense na confecção de xaropes para tratamento de males das vias respiratórias. Neste contexto, objetivou-se quantificar a produção de frutos e fundamentar estratégias para possível manejo de populações naturais de B. antiacantha. Foram acompanhadas 39 infrutescências de Janeiro/2008 a Agosto/2008 distribuídas em área de mata secundária na FLONA de Três Barras, SC. Nesta mesma área, indivíduos da espécie foram acompanhados através de estudos demográficos de 2001 a 2008. As infrutescências apresentaram em média 0,68m de comprimento, número médio de 187 frutos/infrutescência, o diâmetro médio dos frutos foi de 1,9 cm e o peso médio das infrutescências de 3,6 kg. A média de frutos aproveitáveis foi de 157 frutos/infrutescência totalizando 2,5 kg. A safra estimada para 2005 foi de 146 kg de frutos ha-1 e 80 kg de frutos ha-1 para 2008, e a renda líquida a partir da produção de xarope foi estimada em R$ 1168,00 por hectare, por ano. Os resultados mostraram que o manejo de B. antiacantha consiste em atividade economicamente interessante e que esta possibilidade, além de complementar a renda de comunidades locais onde a espécie se faz presente, também amplia o valor das áreas com cobertura florestal.

Among the large number of species that have been used as sources of forest byproducts is Bromelia antiacantha, a species native to the Atlantic Forest and that has great potential of use with nourishing, ornamental, industrial and pharmacological characteristics. The fruits of this species are traditionally used in the Northern Plateau of Santa Catarina State, Brazil, in the preparation of syrup for the treatment of respiratory disorders. In this context, the aim of this study was to quantify the production of fruits and to find strategies for the possible management of natural populations of B. antiacantha. A total of 39 inflorescences were observed from January/2008 to August/2008 distributed in a secondary forest area at FLONA (National Forest), Três Barras, Santa Catarina State. In this same area, B. antiacantha individuals were accompanied by demographic studies from 2001 to 2008. The inflorescences presented on average 0.68 m of length, mean number of 187 fruits/inflorescence, mean diameter of fruits of 1.9 cm and mean weight of inflorescences of 3.6 kg. The mean number of usable fruits was 157 fruits/inflorescence and the mean weight of these fruits was 2.5 Kg. The estimated harvest for 2005 was 146 Kg of fruits ha-1 and for 2008, 80 kg of fruits ha-1, and the net income from the syrup production could reach R$ 1168.00 per hectare per year. The results showed that the management of B. antiacantha consists in an economically interesting activity and that this possibility complements the income of local communities where the species occurs, besides increasing the value of forest areas.

Fungos veiculados por sementes comerciais de braquiária / Fungi associated to commercial seed of braquiaria grass

Este trabalho objetivou avaliar a qualidade sanitária de 50 lotes comerciais de sementes de braquiária, produzidos em diferentes regiões nas safras de 2004-2005 e 2005-2006. Sementes de Brachiaria brizantha cvs. Marandu e Xaraés, B. decumbens cv. Basilisk, B. humidicola cv. Humidicola e B. ruziziensis cv. Ruziziensis, destinadas ao comércio interno, foram submetidas ao teste de sanidade pelo método de papel de filtro. Adicionalmente, avaliou-se a sanidade de sementes de 'Marandu' (2 lotes) e 'Basilisk' (1 lote) destinadas à exportação. As sementes foram distribuídas sobre papel de filtro acondicionado em gerbox e incubadas a 20º C, com fotoperíodo de 12h, durante sete dias. Os fungos secundários ou de armazenamento (FSA) mais frequentemente detectados nos lotes de braquiária foram Aspergillus sp. e Rhizopus sp. Quanto aos fungos potencialmente patogênicos (FP), constatou-se elevada frequência dos gêneros Bipolaris. Curvularia. Fusarium e Phoma. Em geral, foi elevada a incidência de Bipolaris sp., Fusarium sp. e Phoma sp. nas sementes. A ocorrência de Phoma sp. foi crítica, pois 42% dos lotes registraram índices superiores a 70%. Bipolaris sp., Fusarium sp. e Phoma sp. também foram associados às sementes de braquiária tipo exportação, em alguns casos, com incidência considerável. Os resultados revelaram que as sementes comerciais de braquiária apresentam baixa qualidade sanitária e que, em todas as regiões produtoras, existe pelo menos um fator afetando a sanidade dessas sementes.

This work aimed to evaluate the sanitary quality of 50 commercial lots of seeds of braquiaria grass, produced in different regions in the crop of 2004­2005 and 2005­2006. The lots consisted of seeds of the cultivars Brachiaria brizantha cvs. Marandu and Xaraes, B. decumbens cv. Basilisk, B. humidicola cv. Humidicola and B. ruziziensis cv. Ruziziensis. Additionally, seeds of 'Marandu' (2 lots) and 'Basilisk' (1 lot) for exportation were analyzed. The blotter test was used, at 20º C under alternating light and darkness in a 12h photoperiod, for 7 days. Aspergillus sp. and Rhizopus sp. were the secondary or storage fungi with greatest frequency in lots of seeds. High frequency of potential pathogenic fungi, specifically of the Bipolaris. Curvularia. Fusarium and Phoma genera, was observed. In general, there was a high incidence of Bipolaris sp., Fusarium sp. and Phoma sp. in braquiaria grass seeds. The occurrence of Phoma sp. was severe, because 42% of the lots showed incidence superior to 70%. Bipolaris sp., Fusarium sp. and Phoma sp. were associated to braquiaria grass seeds for exportation, in some cases, with significant incidence. The results evidenced the low sanitary quality of commercial seeds of braquiaria grass, and demonstrated that in all producer regions there is at least one factor affecting the sanitary quality of these seeds.

Efficacy of benznidazol treatment for asymptomatic chagasic patients from state of Rio Grande do Sul evaluated during a three years follow-up.

The efficacy of benznidazol on the treatment of chagasic patients from the state of Rio Grande do Sul was evaluated during a three-year follow-up. A cohort of 80 asymptomatic chronic chagasic patients or blood bank donors (49 male and 31 female) was studied. Their ages varied from 17-42 years, with a mean and a median of 30 and 35 years, respectively. The 80 patients presented positive serology, hemoculture and polymerase chain reaction (PCR). They were treated with 5 mg/Kg benznidazol twice a day for 60 days. Serological, parasitological and PCR methods were used to evaluate response. Serology was performed using commercial ELISA and indirect immunofluorescence (IFI) tests, parasitemia was monitored by hemoculture in LIT medium and PCR with primers S35/S36 was used to amplify a Trypanosoma cruzi 330 bp kDNA repetitive sequence. PCR positivity of 240 seropositive individuals was compared using DNA preparations from whole blood/guanidine EDTA (GE), buffy-coat/GE and frozen buffy-coat. Fifty non-chagasic individuals were used as negative controls. PCR positivity was 86.7% for the frozen buffy-coat, 71.7% for the GE/buffy-coat and 69.2% for the GE/whole blood. The hemocultures became negative just after treatment and remained negative during the three years of follow-up. In the third year after treatment, 9/80 (11.3%) patients presented negative PCR and, from those, four also presented negative serological tests. Furthermore, a reduction in three serological titers was observed in 27/80 (33.8%) of the patients treated. Taken together, the results show that four of the 80 (5.0%) chronic chagasic patients from the state of Rio Grande do Sul were cured after treatment with benznidazol.

Efficacy of benznidazol treatment for asymptomatic chagasic patients from state of Rio Grande do Sul evaluated during a three years follow-up

The efficacy of benznidazol on the treatment of chagasic patients from the state of Rio Grande do Sul was evaluated during a three-year follow-up. A cohort of 80 asymptomatic chronic chagasic patients or blood bank donors (49 male and 31 female) was studied. Their ages varied from 17-42 years, with a mean and a median of 30 and 35 years, respectively. The 80 patients presented positive serology, hemoculture and polymerase chain reaction (PCR). They were treated with 5 mg/Kg benznidazol twice a day for 60 days. Serological, parasitological and PCR methods were used to evaluate response. Serology was performed using commercial ELISA and indirect immunofluorescence (IFI) tests, parasitemia was monitored by hemoculture in LIT medium and PCR with primers S35/S36 was used to amplify a Trypanosoma cruzi 330 bp kDNA repetitive sequence. PCR positivity of 240 seropositive individuals was compared using DNA preparations from whole blood/guanidine EDTA (GE), buffy-coat/GE and frozen buffy-coat. Fifty non-chagasic individuals were used as negative controls. PCR positivity was 86.7 percent for the frozen buffy-coat, 71.7 percent for the GE/buffy-coat and 69.2 percent for the GE/whole blood. The hemocultures became negative just after treatment and remained negative during the three years of follow-up. In the third year after treatment, 9/80 (11.3 percent) patients presented negative PCR and, from those, four also presented negative serological tests. Furthermore, a reduction in three serological titers was observed in 27/80 (33.8 percent) of the patients treated. Taken together, the results show that four of the 80 (5.0 percent) chronic chagasic patients from the state of Rio Grande do Sul were cured after treatment with benznidazol.

Genetic Diversity in Colletotrichum gloeosporioides from Stylosanthes spp. at Centers of Origin and Utilization.

ABSTRACT Using molecular markers, this work compares the genetic diversity in Colletotrichum gloeosporioides infecting species of the tropical forage legume Stylosanthes at the center of origin in Brazil and Colombia with that of Australia, China, and India, where Stylosanthes spp. have been introduced for commercial use. There was extensive diversity in the pathogen population from Brazil, Colombia, China, and India. The Australian pathogen population was least diverse probably due to its geographical isolation and effective quarantine. The extensive diversity in China and India means that threats from exotic pathogen races to Stylosanthes pastures can potentially come from countries outside the South American center of origin. In Brazil and India, both with native Stylosanthes populations, a high level of genetic differentiation in the pathogen population was associated with sites where native or naturalized host population was widely distributed. There was limited genetic diversity at germplasm evaluation sites, with a large proportion of isolates having identical haplotypes. This contrasts recent pathogenicity results for 78 of the Brazilian isolates that show hot spots of complex races are more common around research stations where host germplasm are tested, but few are found at sites containing wild host populations. For a pathogen in which the same races arise convergently from different genetic backgrounds, this study highlights the importance of using both virulence and selectively neutral markers to understand pathogen population structure.

Pathogenic Variation in Colletotrichum gloeosporioides Infecting Stylosanthes spp. in a Center of Diversity in Brazil.

ABSTRACT Pathogenic variation in Colletotrichum gloeosporioides infecting species of the tropical pasture legume Stylosanthes at its center of diversity was determined from 296 isolates collected from wild host population and selected germ plasm of S. capitata, S. guianensis, S. scabra, and S. macrocephala in Brazil. A putative host differential set comprising 11 accessions was selected from a bioassay of 18 isolates on 19 host accessions using principal component analysis. A similar analysis of anthracnose severity data for a subset of 195 isolates on the 11 differentials indicated that an adequate summary of pathogenic variation could be obtained using only five of these differentials. Of the five differentials, S. seabrana 'Primar' was resistant and S. scabra 'Fitzroy' was susceptible to most isolates. A cluster analysis was used to determine eight natural race clusters using the 195 isolates. Linear discriminant functions were developed for eight race clusters using the 195 isolates as the training data set, and these were applied to classify a test data set of the remaining 101 isolates. All except 11 isolates of the test data set were classified into one of the eight race clusters. Over 10% of the 296 isolates were weakly pathogenic to all five differentials and another 40% were virulent on just one differential. The unclassified isolates represent six new races with unique virulence combinations, of which one isolate is virulent on all five differentials. The majority of isolates came from six field sites, and Shannon's index of diversity indicated considerable variation between sites. Pathogenic diversity was extensive at three sites where selected germ plasm were under evaluation, and complex race clusters and unclassified isolates representing new races were more prevalent at these sites compared with sites containing wild Stylosanthes populations.

Scintigraphic evaluation of tibial shaft fracture healing.

A scintigraphic study of the healing process of type A and B closed tibial shaft fractures was carried out in 40 cases treated non-operatively, comprising 32 men and eight women aged 30.6 yr on average. Scintigraphic scans were obtained with technetium methylenediphosphonate (MDP-Tc99m, 25 mCi) at 6, 12 and 24 weeks after the fracture and an activity index was calculated taking the mean of three consecutive uptake counts for both fractured and normal opposite leg, used for comparison. The results showed that the activity index in general decreased progressively from the first to the third evaluation, with little difference in behaviour between the two types of fractures. However, for B type fractures the activity index remained stable from the first to the second evaluation, followed by a marked decrease at the third evaluation, with a comparable end result for both fracture types. It was concluded that a decrease of the activity index occurs in both types of closed fractures undergoing uneventful healing and that such a decrease can be taken as a parameter for further studies which include delayed union and non-union.

Characterization of Trypanosoma cruzi strains isolated from chronic chagasic patients, triatomines and opossums naturally infected from the State of Rio Grande do Sul, Brazil.

Thirty-five Trypanosoma cruzi strains were isolated from chronic chagasic patients, triatomines and opossums from different municipalities of the State of Rio Grande do Sul. Parasites were characterized by means of mice infectivity, enzyme electrophoresis and randomly amplified polymorphic DNA (RAPD) analysis. Twenty-nine strains were isolated from chagasic patients, 4 from triatomines (2 from Triatoma infestans and 2 from Panstrongylus megistus) and 2 from opossums Didelphis albiventris. Thirty-three T. cruzi strains were of low and 2 strains of high virulence in mice. Both virulent strains were isolated from P. megistus. Isoenzyme analysis of the strains showed 3 different zymodemes. Eleven strains isolated from chagasic patients and 2 from D. albiventris were Z2. Eighteen strains from patients and 2 from T. infestans were ZB and 2 T. cruzi strains isolated from P. megistus were Z1. RAPD profiles obtained with 4 random primers showed a high genetic heterogeneity of the T. cruzi strains. Zymodeme 2 and ZB strains were the more polymorphic. A band sharing analysis of the RAPD profiles of Z2 and ZB strains using 3 primers, showed a very low percentage of shared bands, 20% among 13 ZB strains and 14% among 13 Z2 strains. According to the isoenzyme results, 3 T. cruzi populations were present in State of Rio Grande do Sul. Zymodeme 2 and ZB strains were found infecting man (domiciliar transmission cycle) whereas Z1 strains were found infecting the sylvatic vector P. megistus.

Bilateral transscapholunate dislocations.

Bilateral transscapholunate dislocations were treated with immediate open reduction and internal fixation. Eighteen months after injury the patient was asymptomatic.