The increasing inclusion of technologies in histology teaching: A systematic review.

Histology is part of the curricular base of all health courses, being the basis for understanding the composition of all tissues in the human body. Over the years, more and more technologies have entered the academic environment, with the aim of improving the teaching and learning process. Thus, the objective of this work was to conduct a systematic review on the use of digital technologies in teaching histology. The PICo strategy was used to develop the guiding question and the results were presented in a Prisma Flow. The following platforms were used to search for articles: PubMed, Embase. Web of Science, Science Direct, Medline, Scielo, Periódicos CAPES and LILACS, Open Gray and Google Scholar, with a time limit between 2012 and 2022. The results showed that this area is still little explored, with there not being a wide range of technologies being used and applied in teaching, with gamification and virtual microscopy being the most applied. However, it was realized that the use of these technologies can improve student performance and increase their interest in the subject. Therefore, these tools are great methods to reduce difficulties and encourage the development of a more receptive environment for the histology teaching and learning process.

Aqueous extract OF Moringa oleifera Lam leaves added to freezing extenders damages goat sperm membranes.

BACKGROUND: Semen cryopreservation is a biotechnology used frequently in animal production; however, there are some obstacles, such as those caused by high levels of reactive oxygen species (ROS). Moringa oleifera (MO) is known as a potent source of antioxidants and might be an important adjuvant. OBJECTIVE: The objective of this study was to determine the effect of different concentrations of MO extract supplementation on goat semen cryopreservation efficiency. MATERIALS AND METHODS: Ejaculates (n=6) from four goat breeders were pooled and diluted in skimmed milk (SM) or Tris-egg yolk (TEY)-based extenders and supplemented with different concentrations of MO extract (0, 1, 2 and 5 mg/mL). After the freeze-thaw cycle, sperm kinetics and viability were assessed. RESULTS: With the SM extender, straightness, wobble and plasma membrane integrity were lower than in the control group (P < 0.05). With the TEY extender, wobble was lower in with 5 mg/mL MO extract than in the control group (P < 0.05). As regards sperm ultrastructure, evaluated by SEM, the MO extract, regardless of the diluent used, damaged the membrane of sperm cells in a dose-dependent manner. CONCLUSION: The addition of aqueous extract of MO leaves in both diluents at all concentrations tested affects the parameters of sperm progressivity and damages the plasma membrane in a dose-dependent manner. DOI: 10.54680/fr23310110712.

Bone marrow granulocytes downregulate IL-1ß and TNF production and the microbicidal activity of inflammatory macrophages.

Macrophages play critical roles in inflammation and defense against pathogens, as well as in the return to tissue homeostasis. Macrophage subpopulations displaying antagonistic phenotypes are generally classified as proinflammatory M1, implicated in antipathogen and antitumoral activities, or as anti-inflammatory M2, associated with tissue repair. Granulocytic and monocytic myeloid-derived suppressor cells recruited from the bone marrow to tissues and phagocytosis of apoptotic neutrophils can attenuate macrophage microbicidal activity. Here, we showed that bone marrow neutrophils, but not thioglycollate-recruited neutrophils, directly suppress the responses of macrophages that were previously committed to an inflammatory phenotype. Cocultures of inflammatory macrophages with bone marrow CD11b+Ly6Ghi granulocytes led to reduced release of IL-1ß, TNF-α, and IL-6 by macrophages after lipopolysaccharide stimulation. The suppressive activity was unrelated to granulocyte apoptosis or to secreted factors and required cell-to-cell contact. The suppressive effect was paralleled by reduction in the nuclear levels of the NF-κB p65 subunit, but not of the p50 subunit. Furthermore, bone marrow granulocytes decreased the phagocytic activity of macrophages and their capacity to kill intracellular Escherichia coli. Taken together, these results show that bone marrow granulocytes can function as suppressors of the proinflammatory activity and microbial-killing responses of macrophages.

French maritime pine bark extract (pycnogenol) in association with triple combination cream for the treatment of facial melasma in women: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: Melasma can be recalcitrant to treatment, and relapses are common. Pycnogenol has been reported to be effective in treating melasma. OBJECTIVE: To compare the efficacy, safety and tolerability of 75 mg pycnogenol taken orally twice a day vs. a placebo, in association with the triple combination and broad-spectrum sunscreen for the treatment of facial melasma. METHODS: A randomized, double-blind, parallel, placebo-controlled study was conducted on 44 women with facial melasma in a single centre from May 2019 through November 2019. Patients with melasma were randomly assigned to orally take 75 mg pycnogenol (PYC) or a placebo (PLAC) twice a day for 60 days. Both groups also received tinted sunscreen [Sun Protection Factor (SPF) 50; Persistent Pigment Darkening (PPD) 17] for daytime use and a topical triple combination at bedtime. The primary outcome was a change from the baseline Modified Melasma Area Severity Index (mMASI) score. Secondary outcomes were improvements in the patients' quality of life (MELASQoL), colorimetric indices and Global Aesthetic Improvement Scale (GAIS). RESULTS: All participants completed the trial. The mean (SD) age of the participants was 39 (7) years, and 91% were phototypes III-IV. Both groups exhibited a reduction in mMASI scores, MELASQoL scores and colour contrast (P < 0.01). The mean (CI 95%) reductions of the mMASI scores were 49% (36-61%) for PYC and 34% (16-47%) for PLAC. The reductions in mMASI scores and colorimetric contrast were superior for the PYC group (P < 0.05). The analysis of GAIS resulted in an improvement of 86% (CI 95%: 68-96%) for the participants in the PYC group and 55% (CI 95%: 32-73%) for those in the PLAC group. There were no adverse effects related to oral treatment. CONCLUSION: Pycnogenol is well-tolerated and increases the effectiveness of broad-spectrum sunscreen and the triple combination in the treatment of facial melasma in women.

Efficacy and safety of topical isobutylamido thiazolyl resorcinol (Thiamidol) vs. 4% hydroquinone cream for facial melasma: an evaluator-blinded, randomized controlled trial.

BACKGROUND: Melasma can be refractory to treatment, and relapses are frequent. Thiamidol is a new potent tyrosinase inhibitor that has been found effective as a cosmeceutical for the depigmenting of melasma. OBJECTIVE: This study compared the efficacy and tolerability of topical 0.2% Thiamidol vs. 4% hydroquinone for facial melasma. METHODS: Fifty women with facial melasma participated in a randomized, evaluator-blinded, controlled study from September through November 2020. Patients were randomly assigned to apply a double layer of 0.2% Thiamidol twice a day or 4% hydroquinone cream at bedtime, for 90 days. Both groups received tinted sunscreen (sun protection factor 60, PPD 20). The primary outcome was the change from the baseline Modified Melasma Area Seve:rity Index (mMASI) score. Secondary outcomes were improvements in the patients' quality of life [Melasma Quality of Life Index (MELASQoL)], colourimetry, and Global Aesthetic Improvement Scale (GAIS) evaluation. RESULTS: One participant, from the hydroquinone group, did not complete the study (unrelated to adverse effects). The mean (SD) age of the participants was 43 (6) years, and 86% were phototypes III-IV. Both groups exhibited a reduction in mMASI, MELASQoL, and colour contrast scores (P < 0.01). The mean [95% confidence interval (CI 95%)] reductions of the mMASI scores were 43% (35-50%) for Thiamidol and 33% (23-42%) for hydroquinone. There was no difference between the groups in the reductions in mMASI, MELASQoL, colourimetric contrast and GAIS scores (P ≥ 0.09). The GAIS analysis resulted in an improvement of 84% (CI: 95% 67-97%) for participants in the Thiamidol group and 74% (CI: 95% 61-93%) for those in the hydroquinone group. There were only mild adverse effects in the Thiamidol group, but allergic contact dermatitis was evidenced in two (8%) participants. CONCLUSION: The melasma improvement achieved using 0.2% Thiamidol did not differ from that of 4% hydroquinone cream. Thiamidol can be considered a suitable option for melasma patients with poor tolerability or treatment failure with hydroquinone.

Isoflavones improve collagen I and glycosaminoglycans and prevent bone loss in type 1 diabetic rats.

Objective: The objective of this study was to evaluate the action of soy isoflavones (ISO) and 17ß-estradiol on collagen I (CollI) and sulfated glycosaminoglycans (GAGs) in the bone matrix of diabetic rats.Methods: Sixty adult female rats (Rattus norvegicus albinus) underwent ovariectomy, and then were randomized into six groups of 10 animals each: GI, sham control ovariectomized animals; GII, sham control diabetic (DM) ovariectomized animals; GIII, control ovariectomized animals receiving propylene glycol vehicle; GIV, control ovariectomized DM animals receiving propylene glycol vehicle; GV, ovariectomized DM animals treated with ISO (150 mg/kg by gavage); and GVI, ovariectomized DM animals treated with estrogen (17ß-estradiol, 10 mg/kg, subcutaneously). 17ß-Estradiol was used as a positive control when compared with ISO. To obtain significant depletion of the estrogen levels and subsequent bone loss, a postsurgical period of 90 days was observed. Treatments occurred during 30 consecutive days. After euthanasia, shafts of the animals' femurs were immersed in liquid nitrogen for molecular biology analysis, and the distal femurs were removed and processed for paraffin embedding.Results: ISO (GV) and 17ß-estradiol (GVI) improved bone formation, increasing GAGs and CollI formation when compared to the control group (GIV) (p < 0.05).Conclusions: ISO and 17ß-estradiol contribute to the decrease of bone loss in diabetic rats.

Short communication: Socio-psychological factors influencing dairy farmers' intention to adopt high-grain feeding in Brazil.

This study aimed to apply the theory of planned behavior to determine the effects of attitude, perceived behavioral control, and subjective norms on the intention of dairy farmers toward high-grain feeding. Quantitative data were collected through interviews with 150 dairy farmers in Paraná, Brazil. Partial least squares structural equation modeling was used to analyze the data. We observed that farmers with a positive perception of grain feeding (attitude) and a positive perception of their ability to increase the use of grains (perceived behavioral control) had higher intention to increase grain feeding. Social pressure (subjective norm) had no effect on the intention to grain feed. These results can contribute to the development of public strategies and policies that encourage the use of high-grain diets in dairy farms.

Investigation of the esthetic outcomes of white spot lesion treatments.

OBJECTIVE: The present study compared the ability of bleaching, resin infiltration and microabrasion to restore the appearance of existing white spot lesions (WSL) on tooth surfaces as close as possible to that of the original healthy enamel. MATERIALS AND METHODS: Sixty extracted human teeth with WSL were randomly assigned to three treatment groups (20/group). Prior to treatment, the colour of the surrounding healthy enamel and the WSL were measured as the baseline and pre-treatment (PreRX) colours respectively using spectrophotometer based on CIE L*A*B. The L-value was used for the statistical comparison. WSLs in each group were treated respectively by bleaching, infiltration or microabrasion following the manufacturer's instructions. Colour measurement was repeated after treatment. Both intragroup and intergroup comparisons were performed using ANOVA followed by Tukey's multiple comparison test (α=0.05). RESULT: In all groups the mean L-values were significantly higher in PreRX WSL (P < 0.01; Tukey) compared to baseline (sound enamel). After treatment the difference in mean L-value between baseline and WSL increased significantly (P < 0.01, Tukey) in Bleaching and Microabrasion groups by 1.4% and 1% respectively, but decreased in Infiltration group by 3.4%. Thus resin infiltration decreased the L-value of the WSL, bringing it closer to the L-value of the sound enamel while bleaching and microabrasion increased the L-value. CONCLUSIONS: Among the three treatment modalities investigated in this study, resin infiltration was the most effective in masking the WSLs.

Association of high-fat diet with neuroinflammation, anxiety-like defensive behavioral responses, and altered thermoregulatory responses in male rats.

Overweight and obesity are a worldwide pandemic affecting billions of people. These conditions have been associated with a chronic low-grade inflammatory state that is recognized as a risk factor for a range of somatic diseases as well as neurodevelopmental disorders, anxiety disorders, trauma- and stressor-related disorders, and affective disorders. We previously reported that the ingestion of a high-fat diet (HFD; 45% fat kcal/g) for nine weeks was capable of inducing obesity in rats in association with increased reactivity to stress and increased anxiety-related defensive behavior. In this study, we conducted a nine-week diet protocol to induce obesity in rats, followed by investigation of anxiety-related defensive behavioral responses using the elevated T-maze (ETM), numbers of FOS-immunoreactive cells after exposure of rats to the avoidance or escape task of the ETM, and neuroinflammatory cytokine expression in hypothalamic and amygdaloid nuclei. In addition, we investigated stress-induced cutaneous thermoregulatory responses during exposure to an open-field (OF). Here we demonstrated that nine weeks of HFD intake induced obesity, in association with increased abdominal fat pad weight, increased anxiety-related defensive behavioral responses, and increased proinflammatory cytokines in hypothalamic and amygdaloid nuclei. In addition, HFD exposure altered avoidance- or escape task-induced FOS-immunoreactivity within brain structures involved in control of neuroendocrine, autonomic, and behavioral responses to aversive stimuli, including the basolateral amygdala (BLA) and dorsomedial (DMH), paraventricular (PVN) and ventromedial (VMH) hypothalamic nuclei. Furthermore, rats exposed to HFD, relative to control diet-fed rats, responded with increased tail skin temperature at baseline and throughout exposure to an open-field apparatus. These data are consistent with the hypothesis that HFD induces neuroinflammation, alters excitability of brain nuclei controlling neuroendocrine, autonomic, and behavioral responses to stressful stimuli, and enhances stress reactivity and anxiety-like defensive behavioral responses.

Comparison of obstetrical interventions in women with vaginal and cesarean section delivered: cross-sectional study in a reference tertiary center in the Northeast of Brazil.

OBJECTIVE: To compare the performance of obstetrical interventions and maternal and perinatal outcomes between vaginal and cesarean delivery routes in pregnant women at normal risk. Type of article: Original article. Desing: Cross-sectional study with 421 participants admitted for spontaneous or induced labor with full-term singleton gestations and fetuses weighing between 2,500 and 4,499 g. SETTING: Maternal Fetal-Medicine Service, Assis Chateaubriand Maternity, Federal University of Ceará (UFC), Fortaleza-CE, Brazil. METHODS: The instrument of data collection was divided into socio-demographic, clinical, and obstetric characteristics; data of labor and delivery; maternal morbidity; maternal outcome and perinatal outcomes. Pearsons chi-square test and Fishers exact test were used to verify associations between the groups. RESULTS: The mean age was 22.8 ± 6.0 (vaginal) and 22.9 ± 4.9 (cesarean section). Overall, 44.5% of vaginal deliveries and 85.5% of cesarean sections were monitored electronically (p < 0.001). Immediate skin-to-skin contact (84.1%) and first-hour breastfeeding (80.4%) were more frequent in vaginal deliveries compared with cesarean deliveries (27% vs. 61.0%, p < 0.001). The prevalence of puerperal infections was 1.2% (vaginal) and 5.0% (cesarean section) with a p value of 0.02; 40% of cesarean-delivered newborns and 9.7% of vaginally-delivered newborns were referred to the neonatal intensive care unit (p < 0.001). CONCLUSION: The cesarean section was associated with a lower frequency of useful practices, a higher frequency of harmful practices, worse neonatal outcomes, and a higher rate of postpartum infections.

Nutritional evaluation of the legume Macrotyloma axillare using in vitro and in vivo bioassays in sheep.

This study consisted of two experiments with the following objectives: to evaluate the effects of tannins from the tropical legume macrotiloma (Macrotyloma axillare) on total gas and methane (CH4 ) production, as well as on ruminal fermentation parameters by performing an in vitro bioassay, with samples incubated with and without polyethylene glycol (PEG) in a semi-automatic system; and secondly in a 17 day in vivo experiment, to determine apparent total tract digestibility (ATTD) of dietary nutrients and ruminal fermentation parameters of 12 intact 8- to 9-month-old Santa Inês (averaging 24.95 ± 1.8 kg body weight) ewes fed tropical grass hay supplemented with macrotiloma hay. The ewes were divided into two treatment groups depending on their diet: chopped aruana grass hay (Panicum maximum cv. Aruana) (control-CON); and aruana grass hay supplemented with chopped macrotiloma hay (macrotiloma-MAC). The animals were kept for 5 consecutive days in metabolic cages for the ATTD assay, and at the end of this period, samples of rumen fluid were collected from each ewe to determine ammoniacal nitrogen (NH3 -N) and short-chain fatty acid (SCFA) production, and protozoa count. For the in vitro assay, a decrease in total gas and CH4 production was observed for samples incubated without PEG (p < .05). No differences were observed for the other parameters evaluated (p > .05). In the in vivo experiment, increased intake and ATTD of crude protein were observed for the animals fed MAC when compared to CON (p < .05). For rumen fermentation parameters, increased NH3 -N, total SCFA and isobutyrate concentrations, as well as reduced protozoa count were observed for MAC when compared to CON (p < .05). The results observed here indicated the potential of macrotiloma for use as a ruminant feed, and antimethanogenic potential of this plant was noted.

Analysis of Paracoccidioides lutzii mitochondria: a proteomic approach.

The genus Paracoccidioides is composed of thermal dimorphic fungi, causative agents of paracoccidioidomycosis, one of the most frequent systemic mycoses in Latin America. Mitochondria have sophisticated machinery for ATP production, which involves metabolic pathways such as citric acid and glyoxylate cycles, electron transport chain and oxidative phosphorylation. In addition, this organelle performs a variety of functions in the cell, working as an exceptional metabolic signalling centre that contributes to cellular stress responses, as autophagy and apoptosis in eukaryotic organisms. The aim of this work was to perform a descriptive proteomic analysis of mitochondria in Paracoccidioides lutzii yeast cells. After mitochondria fractionation, samples enriched in mitochondrial proteins were digested with trypsin and analysed using a NanoUPLC-MSE system (Waters Corporation, Manchester, UK). Ours results revealed that the established protocol for purification of mitochondria was very effective for P. lutzii, and 298 proteins were identified as primarily mitochondrial, in our analysis. To our knowledge, this is the first compilation of mitochondrial proteins from P. lutzii, to date. Copyright © 2016 John Wiley & Sons, Ltd.

Effects of soy isoflavones on the concentration of hyaluronic acid in the vagina of type 1 diabetic rats.

OBJECTIVE: To assess the effects of isoflavones and 17ß-estradiol on the vaginal epithelium extracellular matrix and hyaluronic acid (HA) in the diabetic rat model. METHODS: Sixty adult, virgin, female rats underwent ovariectomy, then randomization into six groups of ten animals each: GI, sham ovariectomized control animals; GII, sham ovariectomized control diabetic animals; GIII, control ovariectomized rats receiving propylene glycol vehicle; GIV, control ovariectomized diabetic animals receiving propylene glycol vehicle; GV, diabetic ovariectomized animals treated with soy isoflavones (150 mg/kg by gavage); GVI, ovariectomized diabetic rats treated with estrogen (17ß-estradiol, 10 mg/kg, subcutaneously). Treatment took place over 30 consecutive days. After euthanasia, a portion of the vagina was immersed in liquid nitrogen for RT-qPCR and Western blotting. Another portion was processed for paraffin embedding. Sections were stained with hematoxylin & eosin for histomorphometry and Picro Sirius Red for collagen quantification. RESULTS: Vaginal epithelium histomorphometry in GIII (15.3 ± 1.1 µm) and GIV (14.5 ± 1.8 µm) was thinner than in GV (41.3 ± 1.5 µm) and GVI (74.3 ± 1.6 µm). There was an increase in collagen content in GV (84.1 ± 1.2 µm) and GVI (88.2 ± 1.7 µm). HA quantification was higher in GV (0.38 ± 1.1 µg/mg) and GVI (0.49 ± 1.4 µg/mg) when compared with GIII (0.12 ± 1.1 µg/mg) and GIV (0.10 ± 1.2 µg/mg), p < 0.05. CONCLUSIONS: Soy isoflavones increase hyaluronic acid concentration in the vagina of diabetic ovariectomized rats. Such findings might help to attenuate the effects of vulvovaginal atrophy in women.

Development of a polymorphic short tandem repeat locus multiplex system for efficient human identification.

This study aimed to develop a short tandem repeat (STR) multiplex system, made up of 22 highly informative STR loci, for application in forensic genetics. The system comprised 21 polymorphic autosomal loci (D3S1358, TH01, D21S11, D18S51, Penta E, D5S818, D13S317, D7S820, D16S539, CSF1PO, Penta D, vWA, D8S1179, TPOX, FGA, D2S441, D17S1301, D19S433, D18S853, D20S482, and D14S1434) and the amelogenin gene locus. Strategies were developed to overcome the challenges involved in creating a multiplex system. Based on the literature and available databases, the STR loci were selected with the aim to obtain discriminatory markers, and followed specific criteria for this purpose. Primers were projected using the Primer3 software, and AutoDimer was used to evaluate possible interactions between them. The 22 selected STR loci were validated individually and jointly, both to assess their sensitivity and to test the efficiency of the multiplex system. Statistical analyses were based on the genetic data of 450 unrelated individuals living in the State of Goiás, thus allowing the establishment of the parameters necessary to use this system. A total of 239 alleles were detected for the 22 loci in the set, allowing for a probability of identity of 4.23 x 10-25 to be obtained. The combined power of discrimination was 0.999999999999999999999999 and the combined power of exclusion was 0.99999. Upon complete validation of the entire system, this multiplex assay was considered to be a powerful tool for application in human identification by DNA analysis.

Wheat gluten intake increases weight gain and adiposity associated with reduced thermogenesis and energy expenditure in an animal model of obesity.

BACKGROUND/OBJECTIVES: The association between gluten and body weight is inconsistent. Previously, we showed that a gluten-free diet reduces weight gain without changing food intake in mice fed high-fat diets. In the present study, we investigated the effects of gluten intake on fat metabolism, thermogenesis and energy expenditure in mice fed a standard or high-fat diet. METHODS: Mice were fed four different experimental diets during 8 weeks: a control-standard diet (CD), a CD added with 4.5% of wheat gluten (CD-G), a high-fat diet (HFD) and a HFD added with 4.5% of wheat gluten (HFD-G). After 8 weeks, the mice received (99m)Tc-radiolabeled gluten orally to study gluten absorption and biodistribution or they underwent indirect calorimetry. After killing, subcutaneous and brown adipose tissues (SAT and BAT) were collected to assess thermogenesis-related protein expression. Lipid metabolism was studied in adipocyte cultures from the four groups. RESULTS: Despite having had the same energy intake, CD-G and HFD-G mice exhibited increased body weight and fat deposits compared with their respective controls. (99m)Tc-GLU or its peptides were detected in the blood, liver and visceral adipose tissue, suggesting that gluten can even reach extraintestinal organs. Uncoupling protein-1 expression was reduced in the BAT of HFD-G and in the SAT of CD-G and HFD-G mice. Indirect calorimetry showed lower oxygen volume consumption in CD-G and HFD-G groups compared with their controls. In HFD mice, daily energy expenditure was reduced with gluten intake. Gluten also reduced adiponectin, peroxisome proliferator-activated receptor (PPAR)-α and PPARγ and hormone-sensitive lipase in cultures of isolated adipocytes from HFD mice, whereas in the CD-G group, gluten intake increased interleukin-6 expression and tended to increase that of tumor necrosis factor. CONCLUSIONS: Wheat gluten promotes weight gain in animals on both HFD and CD, partly by reducing the thermogenic capacity of adipose tissues.

Investigating genetic diversity in sapucaia using inter simple sequence repeat markers.

Sapucaia is a tree species originating from the Brazilian Amazon and is widely distributed in Brazil, especially in the mid-north region (Piauí and Maranhão states). Its seeds are rich in calories and proteins, and possess great potential for commercialization. Little is known about the genetic variability in the germplasm of most Lecythis species. Here, 11 inter-simple sequence repeat primers were used to estimate the genetic variability among 17 accessions, and to determine the levels of genetic variation and the standards of population structure in sapucaia. The accessions were obtained from the active germplasm bank (AGB) of Embrapa Meio-Norte, Teresina, PI, Brazil, and corresponded to four occurrence areas. Ninety-six loci were analyzed among the studied individuals. High variation was found at the species level, where the percentage of polymorphic bands was 94.79%, Nei's genetic diversity (h) was 0.3110, and Shannon's index (I) was 0.4732. In the analyzed populations, the percentage polymorphism ranged from 20.83 to 94.79%, Nei's genetic diversity ranged from 0.0863 to 0.2969, and Shannon's index ranged from 0.1260 to 0.4457. Significant genetic differentiation was detected among the populations (ΦST = 10.66%); however, the greatest genetic differentiation was found within the populations (89.34%), between which there was an intermediate level of gene flow (Nm = 1.10). Accessions BGS 2 and BGS 4 were the most divergent, whereas accessions BGS 14 and BGS 15 were the most similar. Therefore, sapucaia analyzed from the AGB present an elevated level of genetic diversity and may have potential use in genetic breeding programs.

DNase concentration assay to obtain DNA-free RNA from sugarcane leaves.

The success of gene expression studies, protein synthesis, and construction of cDNA libraries directly depends on the purity and integrity of the RNA used in these tests, as even minor amounts of contaminant DNA (<1%) can produce a false positive amplification signal in quantitative real-time PCR. For RNA contaminated with genomic DNA, an essential step in the studies on gene expression is the treatment of the RNA samples with DNase. This study was conducted to test three different concentrations of DNase I (0.02, 0.04, and 0.06 µL/​​ng of RNA), which were chosen based on the results of the RNA sample quantifications and as indicated by the manufacturer, to digest genomic DNA present in the RNA samples extracted from sugarcane leaves with the Concert™ Plant RNA Reagent. The results showed that all three concentrations of DNase significantly reduced DNA concentrations. However, RNA was also degraded on DNase I treatment. In addition, the amount of DNA present in the RNA samples after purification with DNase I was sufficient for its amplification in the tests conducted with conventional PCR. Furthermore, the condition of RNA samples obtained after the treatments allowed for real-time PCR. Therefore, we concluded that 0.02 µL DNase I was the ideal concentration for sugarcane RNA purification, as higher concentrations do not increase the efficiency of the genomic DNA digestion in RNA samples and only make the purification process more expensive. This study provides important information on the effect of high concentrations of DNase I and complements previous studies that have so far tested only the DNase concentration recommended by the manufacturer.

Interpreting the effect of increasing COD loading rates on the performance of a pre-anoxic MBBR system: implications on the attached and suspended biomass dynamics and nitrification-denitrification activity.

A pre-anoxic MBBR system was subjected to increasing organic loading rates up to 18 gCOD/(m(2) day). At 3 gCOD/(m(2) day), most of the incoming organic matter was removed via denitrification. However, at higher loads, anoxic COD removal became limited by the nitrite/nitrate supply from the aerobic reactor, which assumed an important role in this conversion. Despite the application of low dissolved oxygen (DO) levels (<2 mg/L) in this tank, nitrification was observed to be nearly complete until 8 gCOD/(m(2) day). As the organic input was increased, the maximum specific nitrifying activity gradually declined. Activity tests suggested that an oxygen-limited environment was established in the biofilm. At lower loads [3-8 gCOD/(m(2) day)], the nitrification product obtained was affected by the DO concentration, whereas from 16 to 21 gCOD/(m(2) day), nitrite/nitrate profiles were likely associated with microbial stratification in the biofilm. The results also indicated that the role of the suspended biomass in the overall nitrification and denitrification can be very significant in high loaded MBBRs and should not be neglected, even at low HRTs.

Genetic variation detected by RAPD markers in natural populations of babassu palm (Attalea speciosa Mart.).

The purpose of this study was to analyze the effects of management on the genetic structure of natural populations of Attalea speciosa in the State of Piauí, Brazil, using random-amplified polymorphic DNA (RAPD) markers. Three babassu populations under different management systems were selected. Polymerase chain reactions were performed for 20 RAPD primers. A total of 146 bands were generated, 141 of which were polymorphic (96.58%), with a variation of 4 and 12 loci and an average of 7 bands per primer. A dendrogram revealed a clear separation between the three populations (0.57). Data reliability and node consistency were verified by bootstrap values and the cophenetic correlation coefficient (88.15%). Coefficients of similarity between pairs of genotypes ranged from 0.26 to 0.86, with a mean of 0.57. Nei's genetic diversity index (HE) value of the population sampled in Teresina was 0.212, of Esperantina it was 0.195, and of José de Freitas it was 0.207. After the HE was decomposed, the complete diversity was found to be 0.3213. Genetic differentiation between populations was 0.362, and the estimation of gene flow between populations was low (0.879). Analysis of molecular variance revealed that 59.52% of the variation was contained within populations, and 40.48% was between populations. RAPD markers were effective for genetic diversity analysis within and between natural babassu populations, and exhibited a high level of polymorphism. Genetic diversity was the highest within populations; variability was lower in the managed populations than in the undisturbed populations.