Author
Ortrud Monika Barth
Other affiliations: Federal University of Rio de Janeiro
Bio: Ortrud Monika Barth is an academic researcher from Oswaldo Cruz Foundation. The author has contributed to research in topics: Pollen & Virus. The author has an hindex of 31, co-authored 224 publications receiving 3812 citations. Previous affiliations of Ortrud Monika Barth include Federal University of Rio de Janeiro.
Topics: Pollen, Virus, Dengue virus, Bee pollen, Dengue fever
Papers published on a yearly basis
Papers
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TL;DR: The data obtained using chemical and microscopic analysis can play an important role in the quality control of dry bee pollen pellets if the samples are mostly monofloral, due to the intraspecific differences from the taxa collected.
361 citations
TL;DR: Current knowledge on the occurrence of several types of pollen grains in the sediments of honey samples, propolis and bee loads of Apiinae and Meliponinae in Brazil is reviewed.
Abstract: This paper reviews current knowledge on the occurrence of several types of pollen grains in the sediments of honey samples, propolis and bee loads of Apiinae and Meliponinae in Brazil. After a short historical introduction about research activities in Melissopalynology using Brazilian samples, bee products were analyzed in respect to the greater Brazilian regions (South, Southeast, Northeast and North), emphasizing monofloral honeys and the green propolis. Numerous bibliographic references and a short glossary of the technical terms used is presented.
180 citations
Journal Article•
TL;DR: The entomological origin of the honey was known for 17 species of Meliponini from Brazil, one from Costa Rica, six from Mexico, 27 from Panama, one of Surinam, two from Trinidad & Tobago, and seven from Venezuela as mentioned in this paper.
Abstract: SUMMARY Compositional data from 152 stingless bee (Meliponini) honey samples were compiled from studies since 1964, and evaluated to propose a quality standard for this product. Since stingless bee honey has a different composition than Apis mellifera honey, some physicochemical parameters are presented according to stingless bee species. The entomological origin of the honey was known for 17 species of Meliponini from Brazil, one from Costa Rica, six from Mexico, 27 from Panama, one from Surinam, two from Trinidad & Tobago, and seven from Venezuela, most from the genus Melipona. The results varied as follows: moisture (19.9-41.9g/100g), pH (3.15-4.66), free acidity (5.9-109.0meq/ Kg), ash (0.01-1.18g/100g), diastase activity (0.9-23.0DN), electrical conductivity (0.49-8.77mS/cm), HMF (0.4-78.4mg/Kg), invertase activity (19.8-90.1IU), nitrogen (14.34-144.00mg/100g), reducing sugars (58.0-75.7g/100g) and sucrose (1.1-4.8g/100g). Moisture content of stingless bee honey is generally higher than
173 citations
TL;DR: Examination of the intestinal contents of free-living Oryzomys nigripes rats by PAGE revealed two sharply defined bands that could be stained by ethidium bromide or by silver nitrate with comparable intensities, suggesting that these particles represent an as yet undescribed virus with a bisegmented double-stranded RNA genome, for which the name 'picobirnavirus' is proposed.
Abstract: Examination of the intestinal contents of free-living Oryzomys nigripes rats by PAGE revealed two sharply defined bands that could be stained by ethidium bromide or by silver nitrate with comparable intensities. The molecules forming these bands were susceptible to digestion by pancreatic RNase A but not by RNase T1 or by DNase I. Their lengths were estimated to be about 2.6 and 1.5 kbp, respectively, by comparison with rotavirus SA11 genome segments. They cosedimented in CsCl gradients at a density of 1.39 to 1.40 g/ml, together with uniform particles approximately 35 nm in diameter with indistinct surface structure. It is suggested that these particles represent an as yet undescribed virus with a bisegmented double-stranded RNA genome, for which the name 'picobirnavirus' is proposed.
103 citations
TL;DR: Testing the feasibility of BALB/c mice as an experimental model in the study of dengue disease revealed liver injury with viral antigens detection, and data correlate to the development of the disease described in humans.
98 citations
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TL;DR: Higher peak titers were associated with increased disease severity for the 31 patients with a peak titer identified, and increased dengue disease severity correlated with high viremia titer, secondary d Dengue virus infection, and DEN-2 virus type.
Abstract: Viremia titers in serial plasma samples from 168 children with acute dengue virus infection who were enrolled in a prospective study at 2 hospitals in Thailand were examined to determine the role of virus load in the pathogenesis of dengue hemorrhagic fever (DHF). The infecting virus serotype was identified for 165 patients (DEN-1, 46 patients; DEN-2, 47 patients; DEN-3, 47 patients, DEN-4, 25 patients). Patients with DEN-2 infections experienced more severe disease than those infected with other serotypes. Eighty-one percent of patients experienced a secondary dengue virus infection that was associated with more severe disease. Viremia titers were determined for 41 DEN-1 and 46 DEN-2 patients. Higher peak titers were associated with increased disease severity for the 31 patients with a peak titer identified (mean titer of 107.6 for those with dengue fever vs. 108.5 for patients with DHF, P=.01). Increased dengue disease severity correlated with high viremia titer, secondary dengue virus infection, and DEN-2 virus type.
1,548 citations
TL;DR: Results suggest that ZIKV abrogates neurogenesis during human brain development when it targets human brain cells, reducing their viability and growth as neurospheres and brain organoids.
Abstract: Since the emergence of Zika virus (ZIKV), reports of microcephaly have increased considerably in Brazil; however, causality between the viral epidemic and malformations in fetal brains needs further confirmation. We examined the effects of ZIKV infection in human neural stem cells growing as neurospheres and brain organoids. Using immunocytochemistry and electron microscopy, we showed that ZIKV targets human brain cells, reducing their viability and growth as neurospheres and brain organoids. These results suggest that ZIKV abrogates neurogenesis during human brain development.
975 citations
TL;DR: The fossil record for angiosperm pollen types which are comparable to recent taxa is evaluated, following a similar survey published in 1970, with special attention paid to the dating of the sediments.
Abstract: The fossil record for angiosperm pollen types which are comparable to recent taxa is evaluated, following a similar survey published in 1970. Special attention is paid to the dating of the sediments. Evidence for 139 families is considered to be reliable, for others the records are cited as provisional, pending the accumulation of more evidence. Some published records are shown to be erroneous.
919 citations
TL;DR: Dengue virus (DENV) modifies ER membrane structure to promote replication and efficient encapsidation of the genome into progeny virus, which could explain the coordination of distinct steps of the flavivirus replication cycle.
915 citations