Ecology, Evolution, Behavior and Systematics, Aquatic Science, Plant Science
10
Scopus Publications
Scopus Publications
Hidden generic diversity in desmids: description of Pseudomicrasterias gen. nov. (Desmidiaceae, Zygnematophyceae) Camila Barbosa de Araújo, Carlos Eduardo de Mattos Bicudo, Thaís Garcia da Silva, Jan Šťastný, Kateřina Trumhová, Pavel Škaloud Phycologia, 2022 The taxonomy and nomenclature of Micrasterias arcuata are very problematic because of a wide morphological variation and the large number of poorly circumscribed infraspecific taxa. This study aimed at evaluating the phylogenetic position of strains traditionally assigned to M. arcuata based on molecular and phylogenetic approaches, and morphometric analyses. Multigene analyses were performed using the nuclear SSU rDNA and both chloroplast rbcL and psaA markers. Genetic analyses revealed that all three investigated strains of M. arcuata formed reasonably well-supported lineages, separate from all species of the core Micrasterias lineage and closely related to the Euastrum 2 lineage. Morphometric analyses exhibited differences among strains revealing important trends for morphological differentiation and delimitation of infraspecific taxa assigned to M. arcuata. All three investigated strains are separated by their morphological features and represent different taxonomic entities from the molecular and phylogenetic points of view. Available data support the proposal of Pseudomicrasterias gen. nov. within the family Desmidiaceae. One infraspecific taxon is erected to species level and classified as new combination of Pseudomicrasterias, and two new species are recognized.
Revised phylogenetic position of Nephrocytium Nägeli (Sphaeropleales, Chlorophyceae), with the description of Nephrocytiaceae fam. nov. and Nephrocytium vieirae sp. nov. Thaís Garcia da Silva, Lenka Štenclová, Naiara Carolina Pereira Archanjo, Inessa Lacativa Bagatini Taxon, 2021 The common planktonic green algal genus Nephrocytium was traditionally assumed to have a close relationship with the genus Oocystis and accordingly has been included in the family Oocystaceae. Although the position of Nephrocytium within the Oocystaceae has differed according to some authors over the years, its inclusion in the family has not been questioned. Following molecular studies of Oocystis, the Oocystaceae (including Nephrocytium) was removed from the class Chlorophyceae and placed in the Trebouxiophyceae. However, recent molecular studies of some of the former Oocystaceae members have returned them to the Chlorophyceae. These studies suggested the placement of Nephrocytium in the Sphaeropleales, but no taxonomic positioning within the order has been determined for the genus. The relocation of Nephrocytium agrees with a strong morphological trait – it lacks the oocystaceaean multilayered ultrastructure of the cell wall. Based on molecular markers (18S rDNA and tufA), and optical and electron microscopy, the present study aimed to establish the relationships of the genus within the Sphaeropleales. The results support the recognition of a new family, the Nephrocytiaceae, to accommodate Nephrocytium. Furthermore, we have carried out a review of previously described Nephrocytium species and based on morphological and molecular data we propose the description of Nephrocytium vieirae sp. nov.
Prevalence and risk factors for bluetongue in the State of São Paulo, Brazil Thaís G. da Silva, Michele S. Lima, Massimo Spedicato, Irene Carmine, Liana Teodori, Alessandra Leone, Maira S. N. Martins, Fernando G. Buchala, Klaus S. Hellwig, Adriana H. de Campos Nogueira Romaldini, Eliana De Stefano, Giovanni Savini, Edviges M. Pituco Veterinary Medicine and Science, 2018 Bluetongue (BT), caused byBluetongue virus(BTV), is a disease that affects ruminants such as cattle, sheep, goats and deer. BTV is transmitted by female midges of the genusCulicoides. In Brazil, information on the prevalence of BTV in cattle is limited, so the objective of this work was to identify BTV serotypes in cattle. The State of São Paulo was divided into seven cattle‐producing regions, and in each of them, 300 cattle farms were randomly selected. One animal from each farm (out of a total of 1,598 farms) was selected and its sera tested by virus neutralization technique against BTV serotypes (1–24 and 26) for determining antibody titre. Moreover, for each sampled farm, an epidemiological questionnaire was submitted to verify the type of cattle production and the zootechnical and sanitary practices carried out, which could be associated with a higher risk of BTV infection. In this study, antibodies (percentage, [95% confidence interval]) were identified against 11 serotypes: BTV‐1 (22.15%, [15.72–27.92]), BTV‐2 (31.03%, [26.65–37.98]), BTV‐3 (18.96%, [12.42–24.90]), BTV‐4 (24.90% [19.41–29.12]), BTV‐9 (6.82%, [1.45–11.72]), BTV‐12 (7.50%, [2.82–12.51]), BTV‐17 (23.90%, [17.35–29.35]), BTV‐19 (10.20%, [4.62–5.56]), BTV‐21 (30.66%, [25.00–36.00]), BTV‐22 (12.14%, [5.91–18.55]), BTV‐26 (57.00%, [51.41–63.59]). In this study, for the first time in Brazil serological evidence of the presence of serotypes BTV‐2, BTV‐9, BTV‐21 and BTV‐26 is reported. The variable ‘new cattle entering herd’ was considered a risk factor for the occurrence of infection (OR = 2.183, 95% CI = 1.6–2.9).
A new species of trichodesmium (cyanobacteria) from freshwaters, Brazil Célia L. Sant'Anna, Watson A. Gama, Thais G. Silva, Armando A.H. Vieira Rodriguesia, 2018 Trichodesmium is a typical planktic genus in which trichomes are disposed either in fascicles or radially in rounded colonies. Based on morphological studies, there are eleven species of Trichodesmium, out of which nine are from marine environments and only two from freshwaters. Trichodesmium is mainly known for its capacity to form blooms and produce toxins in marine tropical and subtropical environments. There is no information about the capacity of the freshwater Trichodesmium species to produce toxins. It was only with molecular studies that the taxonomy of marine Trichodesmium started to be solved. However, up to now, no material has been available for molecular analyses of freshwater species. During the studies of microalgae from São Paulo state, a population resembling Trichodesmium was found in a recreational pond. The analyzed organisms formed fascicles of homocyted and not attenuated trichomes and cells with gas vesicles, a set of features that makes them different from the other freshwater Trichodesmium species. Thus, we have described the species Trichodesmium brasiliense sp. nov. based on material from Brazilian inland water. Also, we have suggested revision of some Brazilian literature citations of T. lacustre and their inclusion in the synonym of this new species.
Genetic diversity of BCoV in Brazilian cattle herds Adeline de Mira Fernandes, Paulo E. Brandão, Michele dos Santos Lima, Maira de Souza Nunes Martins, Thais G. da Silva, Vivian da Silva Cardoso Pinto, Larissa T. de Paula, Marta Elisabete S. Vicente, Liria H. Okuda, Edviges M. Pituco Veterinary Medicine and Science, 2018 Bovine coronavirus (BCoV) is one of the main aetiological agents of gastroenteritis in calves, causing significant economic damage to livestock. This study aims to characteriseBCoV genetically on the basis of the N gene. A total of 114 faecal samples from beef and dairy calves with or without clinical symptoms of diarrhoea from five Brazilian states (São Paulo, Minas Gerais, Santa Catarina, Mato Grosso and Bahia) were evaluated between 2008 and 2015 by technique of Semi‐nestedRT‐PCRfor gene N and genealogical analysis. Of the 114 samples analysed, 14.91% (17/114) were positive.BCoV was detected in 22.72% (10/44) of the animals with diarrhoea and in 10% (7/70) of asymptomatic animals.BCoV was identified in calves from rural properties located in all of the regions sampled. Genealogical analysis showed that the Brazilian sequences ofBCoV for the gene which codes for the N protein can be broken down into two distinct clusters, and the samples from this study were closely linked to Asian strains. These results contribute to the molecular characterization ofBCoV in Brazil and are the first report of the circulation ofBCoV in the states of Santa Catarina and Bahia.
Region Growing for Segmenting Green Microalgae Images Vinicius R. P. Borges, Maria Cristina F. de Oliveira, Thais Garcia Silva, Armando Augusto Henriques Vieira, Bernd Hamann IEEE ACM Transactions on Computational Biology and Bioinformatics, 2018 We describe a specialized methodology for segmenting 2D microscopy digital images of freshwater green microalgae. The goal is to obtain representative algae shapes to extract morphological features to be employed in a posterior step of taxonomical classification of the species. The proposed methodology relies on the seeded region growing principle and on a fine-tuned filtering preprocessing stage to smooth the input image. A contrast enhancement process then takes place to highlight algae regions on a binary pre-segmentation image. This binary image is also employed to determine where to place the seed points and to estimate the statistical probability distributions that characterize the target regions, i.e., the algae areas and the background, respectively. These preliminary stages produce the required information to set the homogeneity criterion for region growing. We evaluate the proposed methodology by comparing its resulting segmentations with a set of corresponding ground-truth segmentations (provided by an expert biologist) and also with segmentations obtained with existing strategies. The experimental results show that our solution achieves highly accurate segmentation rates with greater efficiency, as compared with the performance of standard segmentation approaches and with an alternative previous solution, based on level-sets, also specialized to handle this particular problem.
Bovine vaccinia in dairy cattle and suspicion of vesicular disease on milkers in Brazil Thaís Garcia da Silva, Michele dos Santos Lima, Alessandra Marnie Martins Gomes de Castro, Maira de Souza Nunes Martins, Vivian Cardoso Castiglioni, Claudia Del Fava, Liria Hiromi Okuda, Edviges Maristela Pituco Ciencia Rural, 2018 Bovine vaccinia (BV) is a vesicular disease induced by the Vaccinia virus (VACV) that affects milk production and is an occupational zoonosis. This research had the following objectives: (i) detection of VACV by qPCR in cattle with clinical suspicion of vesicular disease; (ii) symptoms characterization in animals and milkers with clinical suspicion of the disease and virus detection in humans; and (iii) identification of risk factors for infections of VACV in herds from several Brazilian states. A total of 471 bovine epithelial samples from dairy farms, in 15 Brazilian states, were evaluated between 2007 and 2012. The samples were tested by quantitative PCR (qPCR) using SYBR Green® reagents, validated with a lower limit of detection of 100TCID50/50µL (1.7x100 viral particles), and 45.1% of VACV positive samples were detected. Using official forms for epidemiological investigation (FORM-IN), the risk factors for VACV infections in cattle were determined to be farms with a lack of technological facilities (P= 0.029) and the presence of rodents (P= 0.001). There was an effect of seasonality in cattle with a higher occurrence of BV during the dry season. A total of 420 epidemiological questionnaires were applied at public health care centers, where 100% of the milkers had vesicular lesions on their hands (98.1%) and on their arms (6.9%). The most frequent clinical symptoms in humans were: local swelling (74.2%), headache (20.7%), fever (10.4%) and inguinal lymphadenopathy (74.2%). Only 19.98% of milkers aged between 39 and 58 years were seroreactive to VACV and were immunized with the human anti-smallpox vaccine. There was an increase in the frequency of BV in older individuals due to their natural decrease in specific immunity. It has been shown that the implementation of zootechnical management techniques and health planning are important for the prevention of BV in animals and humans.
Selenastraceae (Sphaeropleales, Chlorophyceae): RbcL, 18s rDNA and ITS–2 secondary structure enlightens traditional taxonomy, with description of two new genera, Messastrum gen. nov. and Curvastrum gen. nov Thaís Garcia da Silva, Christina Bock, Célia Leite Sant'Anna, Inessa Lacativa Bagatini, Sabina Wodniok, Armando Augusto Henriques Vieira Fottea, 2017 The phylogeny of the family Selenastraceae was investigated by light microscopy, 18S rDNA, rbcL and ITS-2 analyses. Various morphological features traditionally used for species and genera identification were investigated. All selenastracean strains studied have naked pyrenoids within the chloroplast, except the genus Chlorolobion, which presented starch envelope. The molecular analyses showed that no morphological criterion considered so far is significant for the systematics of the Selenastraceae, but a set of features may be suitable to identify the genera Ankistrodesmus and Chlorolobion. Phylogenetic analyses showed the genera Monoraphidium, Kirchneriella and Selenastrum were not monophyletic and not distinguishable as separate genera. The polyphyly of the genus Selenastrum led to the description of two new genera, Curvastrum gen. nov and Messastrum gen. nov.
A Highly Accurate Level Set Approach for Segmenting Green Microalgae Images Vinicius R. Pereira Borges, Bernd Hamann, Thais G. Silva, Armando A.H. Vieira, Maria Cristina F. Oliveira Brazilian Symposium of Computer Graphic and Image Processing, 2015 We present a method for segmenting 2D microscopy images of freshwater green microalgae. Our approach is based on a specialized level set method, leading to efficient and highly accurate algae segmentation. The level set formulation of our problem allows us to generate an algae's boundary curve as the result of an evolving level curve, based on computed background and algae regions in a given image. By characterizing the distributions of image intensity values in local regions, we are able to automatically classify image regions into background and algae regions. We present results obtained with our method. These results are very promising as they document that we can achieve highly accurate algae segmentations when comparing ours against manually segmented images (segmented by an expert biologist) and with results derived by other approaches covered in the literature.
