Clesnan Mendes-Rodrigues

Calculating germination measurements and organizing spreadsheets

Com o objetivo de minimizar as dificuldades dos iniciantes, estamos propondo o uso de planilhas eletronicas convencionais para o calculo das principais medidas de germinacao (ou emergencia), a organizacao dos dados finais para a analise estatistica e alguns comandos eletronicos envolvidos nesses passos.

Polyembryony in Melastomataceae from Brazilian Cerrado: multiple embryos in a small world

Polyembryony has been commonly associated with apomixis in the angiosperms and seems to be more common than expected, even in biomes where sexual reproduction processes are predominant. Recent studies in Cerrado, the Neotropical savannas of Central Brazil, showed high frequencies of apomixis and polyembryony and indicated these processes as reproductive and evolutionary alternatives for plants in these areas. In this sense, we investigated the occurrence of polyembryony and its relationships with ecological (season and type of dispersal, ploidy, species distribution and breeding system) and taxonomic (tribe) factors in the Melastomataceae, a mostly tropical family already known for its high frequency of apomixis and very common in Cerrado. We collected seeds from 69 populations of 53 species, which were sown in germination chambers. After seed germination, the presence and number of seedlings per seed were evaluated as a method to estimate polyembryony. We encountered 18 species (33.96%) with polyembryony (more than one seedling, or gemellar seedlings, originated per seed) concentrated in species of the tribe Miconieae (64%) and Microlicieae (16.67%), but absent in Melastomeae. Monoembryony was present only in sexual species, while all apomictic species were polyembryonic. In Miconia, the polyembryony was correlated with polyploidy, and monoembryony with diploid species. Polyembryony was more common among species with wide distribution in the Cerrado region, which indicates that the presence of gemellar seedlings is important for establishment and survival of the group in the Cerrado biome.

Multiple dormancy and maternal effect on Miconia ferruginata (Melastomataceae) seed germination, Serra de Caldas Novas, Goiás, Brazil

Species with mostly asexual reproduction are interesting subjects for germination studies since variation would be more easily linked to environmental factors. Miconia ferruginata DC. is an apomictic treelet in Brazilian cerrado areas on rocky outcrops. Germination of seeds collected from individuals occurring in the Serra de Caldas Novas State Park, Goias, was studied in three experiments under controlled conditions. Germination characteristics differed among individuals and were correlated with altitude and soil Al content. Seeds from plants growing at lower altitudes, with lower soil aluminium content, presented malformed seeds with absence of embryo which rendered lower, but better synchronized germination. The nested analysis showed that from the total variance, 78.14% for germinability, 54.56% for uncertainty of the germination process, and 68.30% for the quantity of seeds without embryo was attributed to the altitudinal effect. Individuals nested within altitude contributed up to 16.93% for the total variance. It means that there is low variability among individuals of the same altitude and high variability among individuals from different points of the slope, making clear that for the studied population the environmental effect is stronger than the genetic component to determine the seed quality. The testa of the seeds provides a mechanical dormancy which seems to be associated also with phenolic compounds, which help to disperse germination through time. Photoblastism was also registered for seeds of this species.

Pollen and stomata morphometrics and polyploidy in Eriotheca (Malvaceae-Bombacoideae)

Approximately 70% of the angiosperm species are polyploid, an important phenomenon in the evolution of those plants. But ploidy estimates have often been hindered because of the small size and large number of chromosomes in many tropical groups. Since polyploidy affects cell size, morphometric analyses of pollen grains and stomata have been used to infer ploidy level. Polyploidy is present in many species of the Cerrado, the Neotropical savanna region in Central Brazil, and has been linked to apomixis in some taxa. Eriotheca gracilipes and Eriotheca pubescens are common tree species in this region, and present cytotypes that form reproductive mosaics. Hexaploid individuals (2n = 6x = 276) are polyembryonic and apomictic, while tetraploid and diploid individuals (2n = 2x = 92, 2n = 4x = 184) are sexual and monoembryonic. We tested whether morphometric analysis can be used to estimate ploidy levels in E. gracilipes and E. pubescens individuals. Pollen material from diploid and hexaploid individuals of E. gracilipes, and tetraploid and hexaploid individuals of E. pubescens, were fixed in 50% FAA, and expanded leaves were dried in silica gel. Pollen grains and stomata of at least five individuals from each population were measured. The results demonstrate that all measures were significantly different among cytotypes. Individuals with higher levels of ploidy (hexaploid) all presented measurements that were higher than those with lower levels (diploid and tetraploid). There was no overlap between ploidy levels in each species at 95% confidence interval. Thus, the size of the pollen grains and stomata are effective parameters for analysis of ploidy levels in E. gracilipes and E. pubescens.

Sexual ratio and floral biology of the dioecious Neea theifera Oerst. (Nyctaginaceae) in a cerrado rupestre of central Brazil

Dioecy is characterized by a complete separation of sexual functions on male and female plants. It has evolved many times in flowering plants and is widespread among distinct Angiosperm families. It is viewed as a reproductive strategy to reduce endogamy, and to promote optimal resource allocation between male and female sexual functions. Neea theifera is a common species in Cerrado, neotropical savannas in Brazil, but information regarding its reproductive biology is still incomplete. In order to investigate how environmental conditions possibly affect this dioecious species, we studied its floral biology, sex ratio and spatial distribution of sexual morphs along a soil-altitudinal gradient. The sex ratio did not significantly deviate from the expected 1:1 ratio. However, flower abundance in the population was significantly biased towards staminate flowers. Female individuals were larger than male individuals and plant size was negatively correlated with altitude, but did not differ between sexual morphs. The population did not show spatial segregation of sexes and male individuals were sexually mature earlier than female ones. Staminate flowers were larger than pistillate flowers and presented high pollen viability. Meliponini bees, small flies and thrips were potential pollinators, but pollination success was very low. Dioecy in N. theifera corroborates many general features of this reproductive strategy, such as woody habit, inconspicuous flowers, pollination by small generalist insects and differential resource allocation between male and female plants. However, reproduction in this species seems to be impaired by pollinator limitation. The results showed that the soil-altitude gradient influenced the growth pattern of the species and may play an important role in its reproductive biology but did not affect dioecy directly.

Do chromosome numbers reflect phylogeny? New counts for Bombacoideae and a review of Malvaceae s.l.

UNLABELLED • PREMISE OF THE STUDY Whole genome duplication (WGD) and specific polyploidy events marked turning points for angiosperm genome structure and evolution. Therefore, cytogenetic studies of polyploidy-prone groups such as the tropical Malvaceae and plant formations such as as the Brazilian Cerrado have gained further importance. We present new chromosome counts for Cerrado Bombacoideae and revised chromosome numbers for the Malvaceae s.l., compare these between subfamilies, and relate them to phylogenetic signal.• METHODS We studied the chromosome number of Eriotheca candolleana, E. gracilipes, E. pubescens, Pachira glabra, Pseudobombax longiflorum, and P. tomentosum. We also compared Eriotheca species ploidy levels using flow cytometry. We compiled chromosome numbers for 557 species of Malvaceae s.l., including 37 Bombacoideae species. We included this information in a phylogenetic reconstruction based on chloroplast matK-trnK DNA to evaluate chromosome evolution of the Malvaceae s.l. and the Bombacoideae in particular.• KEY RESULTS The Cerrado Bombacoideae presented consistently high chromosome numbers. Numbers for Eriotheca species were among the highest and varied among populations. Flow cytometry analyses showed similar 1Cx DNA for all cytotypes and indicated neopolyploidy. Chromosome numbers differed between subfamilies, with the lowest numbers in the Malvoideae and Byttnerioideae and the highest in Tilioideae. Chromosome numbers had significant phylogenetic signal for Bombacoideae but not for Malvoideae or Malvaceae s.l.• CONCLUSIONS Clearly distinct chromosome numbers allied to monophyly provide some support for a circumscription of the Bombacoideae and distinction within the Malvaceae. The phylogenetic signal for chromosome number supports the idea of an ancient WGD and further neopolyploidy events as important evolutionary trends for the Bombacoideae.

Evaluation of the Multimodal Strategy for Improvement of Hand Hygiene as Proposed by the World Health Organization.

Hand hygiene has the biggest impact and is the least expensive way to prevent and control health care–associated infections. In this study, we assessed the effectiveness of the multimodal strategy of the World Health Organization to improve health care–associated infection rates, hand hygiene compliance, and the related knowledge of health care professionals in a Brazilian university hospital. We observed the necessity for an alternative approach in hospitals with high staff turnover and low attendance of educational sessions.

Could legal requirements in nursing practice trigger actions that would change the rates of urinary tract infections? A case study in Brazil

HighlightsThe published resolution triggered the protocol implementation and nursing training.Catheter‐Associated Urinary Tract Infection (CAUTI) decreased after the resolution.The nursing training was a key factor associated to reduction in CAUTI rates.Low attendance in training apparently did not impair the reduction in CAUTI rates.The changes were important for the solution of the multiple causes of CAUTI. &NA; We evaluated the influence of a Brazilian resolution, published in 2013, that restricts the performing of urinary catheterization to nurses, as opposed to others from different nursing professional categories, on indicators of catheter‐associated urinary tract infection in an intensive care unit. The resolution triggered actions such as the implementation of protocols and nursing staff training that led to behavior changes related to the reduction of catheter‐associated urinary tract infection rates.