New imidazolidinic bioisosters: potential candidates for antischistosomal drugs

The emergence of strains of Schistosoma resistant to praziquantel has drawn attention to the search for new schistosomacide drugs. Imidazolidinic derivatives have performed outstandingly against adult S. mansoni worms when evaluated in vitro. The molecular modification of imidazolidine by way of bioisosteric replacement gives rise to variations in its biological response. This study verifies the potential of substituent groups in the derivatives (Z)3-benzyl-5-(2-fluoro-benzylidene)-imidazolidine-2,4-dione NE4, 3-benzyl-5-(4-chloro-arylazo)-4-thioxo-imidazolidin -2-ona PT5, 3-benzyl-5-(3-fluoro-benzylidene)-1-methyl-2-thioxo-imidazolidin-4-one JT53; 3-benzyl-1-methyl-5-(4-methyl-benzylidene)-2-thioxo-imidazolidin-4-one JT63; 3-benzyl-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo -imidazolidin-4-one JT68; 3-(4-chloro-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT69; 3-(4-phenyl-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT72 by determining the viability in vitro of adult S. mansoni worms in the presence of these derivatives. The susceptibility of the worms obtained from mice and kept in culture in the presence of different concentrations was determined by way of schistosomacide kinetic, observed every 24 h over a period of eight days. The results show that the worms were more sensitive to the PT5 derivative at a concentration of 58 microM which killed 100% of the worms after 24 h of contact, also giving rise to alterations in the tegument surface of the worms with the formation of bubbles and peeling. These observations suggest a strong electronic contribution of the arylazo grouping in the biological response.     

Long‐term regeneration of a tropical plant community after sand mining

Sandy coastal plant communities in tropical regions have been historically under strong anthropic pressure. In Brazil, these systems shelter communities with highly plastic plant species. However, the potential of these systems to regenerate without human assistance after disturbances has hardly been examined. We determined the natural regeneration of a coastal sandy plain vegetation (restinga) in Brazil, 16 years after the end of sand removal. We inventoried 38 plots: 20 within a sand‐mined site and 18 in an adjacent undisturbed site. We expected lower diversity values in the sand‐mined site compared to the undisturbed site, but similar species composition between the two sites due to the spatial proximity of the two sites and the high plasticity of restinga species. Species were ranked using abundance and importance value index in both sites, and comparisons were performed using Rényi entropy profiles, rarefaction curves, principal component analysis, and redundancy analysis. Species composition and dominant species differed markedly between the two sites. Bromeliads and Clusia hilariana, well‐known nurse plants, dominated the undisturbed site but were almost absent in the regenerating site. Species richness did not differ between both sites, but diversity was higher in the undisturbed site. Within‐site composition differences in the mined area were associated with field characteristics. Interestingly, species classified as subordinate or rare in the undisturbed site became dominants in the regenerating site. These newer dominants in the sand‐mined site are not those known as nurse plants in other restingas, thus yielding strong implications for restoration.     

Effect of 1-MCP and low-temperature storage on postharvest conservation of camu–camu

Camu–camu, a native fruit from the Amazon region, is a rich source of bioactive compounds. However, its intense metabolic activity and high-water content limit the fruit’s postharvest storage and marketing. The aim of this study, conducted in two parts, was to evaluate the effects of 1-MCP and storage temperature on the physiology and postharvest preservation of camu–camu fruit. In part 1 of the study, fruit harvested at maturity stage 3 were divided into groups: control, 1-methylcyclopropene (1-MCP; 900 nL L^?1; 12 h) and ethylene (1000 µL L^?1; 24 h) and were stored at 22?±?1 °C and 85?±?5% RH for 9 days. In part 2, fruit harvested at maturity stage 3 were stored at 5, 10, 15, 20, or 25?±?1 °C and 85?±?5% RH for 9 days. During storage, fruit were evaluated daily for decay, mass loss, respiratory activity, and ethylene production, and every 3 days they were evaluated for peel color, pulp firmness, soluble solids content, total titratable acidity, ascorbic acid, total chlorophyll, and total anthocyanins. Fruit treated with 1-MCP exhibited delayed ripening due to lower metabolic activity, as evidenced by delay to softening, reduced mass loss and no decay. Storage at 5 °C prevented ethylene production, mass loss, color changes, and maintained pulp firmness, while did not affect soluble solids content. The results indicated that storage of camu–camu fruit at 5 °C or at 25 °C following application of 900 nL L^?1 1-MCP were effective strategies to delay ripening and maintain fruit quality up to 9 days.     

Carbonate Production by Benthic Communities on Shallow Coralgal Reefs of Abrolhos Bank,Brazil

The abundance of reef builders, non-builders and the calcium carbonate produced by communities established in Calcification Accretion Units (CAUs) were determined in three Abrolhos Bank shallow reefs during the period from 2012 to 2014. In addition, the seawater temperature, the irradiance, and the amount and composition of the sediments were determined. The inner and outer reef arcs were compared. CAUs located on the inner reef shelf were under the influence of terrigenous sediments. On the outer reefs, the sediments were composed primarily of marine biogenic carbonates. The mean carbonate production in shallow reefs of Abrolhos was 579 ± 98 g m^-2 y^-1. The builder community was dominated by crustose coralline algae, while the non-builder community was dominated by turf. A marine heat wave was detected during the summer of 2013–2014, and the number of consecutive days with a temperature above or below the summer mean was positively correlated with the turf cover increase. The mean carbonate production of the shallow reefs of Abrolhos Bank was greater than the estimated carbonate production measured for artificial structures on several other shallow reefs of the world. The calcimass was higher than the non-calcareous mass, suggesting that the Abrolhos reefs are still in a positive carbonate production balance. Given that marine heat waves produce an increase of turf cover on the shallow reefs of the Abrolhos, a decrease in the cover represented by reef builders and shifting carbonate production are expected in the near future.     

FAM5C Contributes to Aggressive Periodontitis

Aggressive periodontitis is characterized by a rapid and severe periodontal destruction in young systemically healthy subjects. A greater prevalence is reported in Africans and African descendent groups than in Caucasians and Hispanics. We first fine mapped the interval 1q24.2 to 1q31.3 suggested as containing an aggressive periodontitis locus. Three hundred and eighty-nine subjects from 55 pedigrees were studied. Saliva samples were collected from all subjects, and DNA was extracted. Twenty-one single nucleotide polymorphisms were selected and analyzed by standard polymerase chain reaction using TaqMan chemistry. Non-parametric linkage and transmission distortion analyses were performed. Although linkage results were negative, statistically significant association between two markers, rs1935881 and rs1342913, in the FAM5C gene and aggressive periodontitis (p = 0.03) was found. Haplotype analysis showed an association between aggressive periodontitis and the haplotype A-G (rs1935881-rs1342913; p = 0.009). Sequence analysis of FAM5C coding regions did not disclose any mutations, but two variants in conserved intronic regions of FAM5C, rs57694932 and rs10494634, were found. However, these two variants are not associated with aggressive periodontitis. Secondly, we investigated the pattern of FAM5C expression in aggressive periodontitis lesions and its possible correlations with inflammatory/immunological factors and pathogens commonly associated with periodontal diseases. FAM5C mRNA expression was significantly higher in diseased versus healthy sites, and was found to be correlated to the IL-1β, IL-17A, IL-4 and RANKL mRNA levels. No correlations were found between FAM5C levels and the presence and load of red complex periodontopathogens or Aggregatibacter actinomycetemcomitans. This study provides evidence that FAM5C contributes to aggressive periodontitis.     

Shorter leukocyte telomere length is associated with severity of COVID-19 infection.

The infection by COVID-19 is a serious global public health problem. An efficient way to improve this disease's clinical management would be to characterize patients at higher risk of progressing to critically severe infection using prognostic biomarkers. The telomere length could be used for this purpose. Telomeres are responsible for controlling the number of maximum cell divisions. The telomere length is a biomarker of aging and several diseases. We aimed to compare leukocyte telomere length (LTL) between patients without COVID-19 and patients with different clinical severity of the infection. Were included 53 patients who underwent SARS-CoV-2 PCR divided in four groups. The first group was composed by patients with a negative diagnosis for COVID-19 (n = 12). The other three groups consisted of patients with a confirmed diagnosis of COVID-19 divided according to the severity of the disease: mild (n = 15), moderate (n = 17) and severe (n = 9). The LTL was determined by Q-PCR. The severe group had the shortest LTL, followed by the moderate group. The negative and mild groups showed no differences. There is an increase of patients with hypertension (p = 0.0099) and diabetes (p = 0.0067) in moderate and severe groups. Severe group was composed by older patients in comparison with the other three groups (p = 0.0083). Regarding sex, there was no significant difference between groups (p = 0.6279). In an ordinal regression model, only LTL and diabetes were significantly associated with disease severity. Shorter telomere length was significantly associated with the severity of COVID-19 infection, which can be useful as a biomarker or to better understand the SARS-CoV-2 pathophysiology.     

Effect of indole-3-acetic acid administration by gavage and by subcutaneous injection on rat leukocytes

This study was done to investigate the effect of indole-3-acetic acid (IAA) administered subcutaneously and by gavage on neutrophil function and cytotoxicity in neutrophils and lymphocytes. A gavage administration resulted in an increase in phagocytic capacity in neutrophils in a dose depended manner for 1 mg, 2 mg, 18 mg, and 40 mg of IAA per kg of body mass, respectively, compared with the control. Similarly, subcutaneous administration of IAA at 2, 18, and 40 mg per kg of body mass promoted a significant rise in phagocytosis by neutrophils. H2O2 production in neutrophils from treated rats by gavage was similar to those receiving subcutaneous IAA treatment, and did not show a significant difference between treatments and control. IAA treatment, whether by gavage or subcutaneous, did not produce an alteration in antioxidant enzyme activities or in glucose-6-phosphate dehydrogenase activity of either neutrophils or lymph nodes. Subcutaneous IAA administration did not alter the neutrophil and lymphocyte death as deduced by unaltered membrane integrity, DNA fragmentation and mitochondrial transmembrane potential, compared with controls. In conclusion, IAA administration either subcutaneously or by gavage could increase the phagocytic capacity by neutrophils and this acid administration did not have prooxidant effects or cytotoxic effects on neutrophils and lymphocytes.     

Ozone-Induced Responses in Croton floribundus Spreng. (Euphorbiaceae): Metabolic Cross-Talk between Volatile Organic Compounds and Calcium Oxalate Crystal Formation

Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O₃) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O₃ and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O₃ induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O₃) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O₃ oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O₃.     

Rhodolith beds are major CaCO3 bio-factories in the tropical South West Atlantic

Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (<150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N-27°S). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50'-19°45'S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km(2). Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO(3) production was estimated from in situ growth assays at 1.07 kg m(-2) yr(-1), with a total production rate of 0.025 Gt yr(-1), comparable to those of the world's largest biogenic CaCO(3) deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.     

Complete mitochondrial genome from South American catfish <Emphasis Type="Italic">Pseudoplatystoma reticulatum</Emphasis> (Eigenmann &amp; Eigenmann) and its impact in Siluriformes phylogenetic tree

The cachara (Pseudoplatystoma reticulatum) is a Neotropical freshwater catfish from family Pimelodidae (Siluriformes) native to Brazil. The species is of relative economic importance for local aquaculture production and basic biological information is under development to help boost efforts to domesticate and raise the species in commercial systems. The complete cachara mitochondrial genome was obtained by assembling Illumina RNA-seq data from pooled samples. The full mitogenome was found to be 16,576 bp in length, showing the same basic structure, order, and genetic organization observed in other Pimelodidae, with 13 protein-coding genes, 2 rNA genes, 22 trNAs, and a control region. Observed base composition was 24.63% T, 28.47% C, 31.45% A, and 15.44% G. With the exception of NAD6 and eight tRNAs, all of the observed mitochondrial genes were found to be coded on the H strand. A total of 107 SNPs were identified in P. reticulatum mtDNA, 67 of which were located in coding regions. Of these SNPs, 10 result in amino acid changes. Analysis of the obtained sequence with 94 publicly available full Siluriformes mitogenomes resulted in a phylogenetic tree that generally agreed with available phylogenetic proposals for the order. The first report of the complete Pseudoplatystoma reticulatum mitochondrial genome sequence revealed general gene organization, structure, content, and order similar to most vertebrates. Specific sequence and content features were observed and may have functional attributes which are now available for further investigation.