Location of the stigmatic areas in Mutisia speciosa Aiton ex Hook. a new floral feature in Asteraceae

In Mutisieae species, the style branches are described as short and the stigmatic areas cover the inside of the style branches. As shown in preliminary observations, the Mutisia speciosa florets had long style branches (7 mm), bifurcate only at the apex (about 1.5 mm) and juxtaposed along the remaining length. The objective was to locate the stigmatic areas in M. speciosa. For this purpose, neutral red, 3% hydrogen peroxide and hand pollinations were used. For the pollinations, florets with cut apical portion of the branches (about 2 mm) and florets with intact branches were used. In the first group of florets, the pollen was deposited along the margins of the juxtaposed branches (about 5 mm), and in the second, the pollen was ventrally deposited on the bifurcated apical portion. Some of these florets were left on the plant until fruiting and others were analyzed under a fluorescence microscope to check pollen tube growth. The neutral red test defined two ventro-marginal bands fused at the apex of each style branch, consisting of papillose cells. Intense bubbling in the hydrogen peroxide test showed that only the bands are receptive. The pollinations resulted in fruit sets and growth of pollen tubes, confirming that the bands are receptive along their entire length. This result is new and indicates the need for further studies on the floral biology of tropical Asteraceae species to improve the understanding of their reproductive attributes.     

Sleep on the Job Partially Compensates for Sleep Loss in Night‐Shift Nurses

Nursing personnel in Brazil are usually submitted to fixed 12 h shifts with no consecutive working days or nights. Moonlighting is common in this group, with a consequent increase in the number of working hours. The possibility of sleeping on the job during the night shift in the studied hospitals had already been described. The present study aims to analyze whether the time devoted to daily activities (sleep, rest, leisure, housework, commuting, personal needs, care of children or other people, non‐paid work, and study) is related to the number of worked hours and to nap‐taking during the night shift. The field study took place at two public hospitals in Rio de Janeiro, Brazil. Workers filled out a structured form on time devoted to the above‐mentioned activities for at least four consecutive days. The time devoted to sleep was analyzed according to its occurrence at home or on the job. Workers were classified according to the number of jobs (one job/two jobs) and the time dedicated to work according to the median of the whole series (below the median/above the median). All workers who had at least one working night were analyzed as to nap‐taking on the job. They were classified according to the sleep occurrence during the night shift—the sleep group and the non‐sleep group, both of which were compared to daytime workers. Statistical treatment of data included non‐parametrical procedures. The study group comprised 144 workers (mean age: 35.7±10.5 years old; 91% women; 78% nurse assistants, the remainder registered nurses). They recorded their daily activities for 4–11 days; 829 cumulative days were analyzed for the whole group. A total of 165 working nights were analyzed; sleep or rest occurred during 112 (68%) of them, with mean sleep/rest duration of 141±86 min. Time devoted to sleep and leisure varied according to the number of working hours, being significantly reduced in those submitted to longer work hours (p<0.001 and p=0.002, respectively). Results close to significance point to a reduction in the time dedicated to housework among workers with long work hours (p=0.053). The time spent on sleep/rest per working night did not differ according to the number of worked hours (p=0.490). A tendency was observed for those who have two jobs to devote more time to sleep/rest on the job (p=0.058). The time of personal needs was significantly lower among those who did not sleep on the job as compared to day workers (p=0.036). The total sleep time was significantly lower among those who did not sleep on the job, as compared to day workers and to those who slept on the job (p=0.004 and p=0.05, respectively). As to home sleep length, workers who slept and those who did not sleep on the job were similar and slept significantly less than exclusively daytime workers (p<0.001 and p=0.002, respectively). Sleeping on the job during the night shift seems to partially compensate for the shorter sleep at home among night workers and may play a beneficial effect in coping with two jobs.     

Genetic profile of the arylamine N-acetyltransferase 2 coding gene among individuals from two different regions of Brazil

Arylamine N-acetyltranferase 2 is the main enzyme responsible for the isoniazid metabolization into hepatotoxic intermediates and the degree of hepatotoxicity severity has been attributed to genetic variability in the NAT2 gene. The main goal of this study was to describe the genetic profile of the NAT2 gene in individuals from two different regions of Brazil: Rio de Janeiro and Goiás States. Therefore, after preparation of DNA samples from 404 individuals, genotyping of the coding region of NAT2 was performed by direct PCR sequencing. Thirteen previously described SNPs were detected in these Brazilian populations, from which seven: 191 G>A; 282 C>T; 341 T>C; 481 C>T; 590 G>A; 803 A>G and 857 G>A are the most frequent in other populations. The presence of so-called ethnic-specific SNPs in our population is in accordance with the Brazilians' multiple ancestry. Upon allele and genotype analysis, the most frequent NAT2 alleles were respectively NAT2*5B (33%), NAT2*6A (26%) and NAT2*4 (20%) being NAT2*5/*5 the more prevalent genotype (31.7%). These results clearly demonstrate the predominance in the studied Brazilian groups of NAT2 alleles associated with slow over the fast and intermediate acetylator genotypes. Additionally, in Rio de Janeiro, a significantly higher frequency of intermediate acetylation status was found when compared to Goiás (42.5% versus 25%) (p=0.05), demonstrating that different regions of a country with a population characterized by a multi-ethnic ancestry may present a large degree of variability in NAT2 allelic frequencies. This finding has implications in the determination of nationwide policies for use of appropriate anti-TB drugs.     

Different roles of the Mre11 complex in the DNA damage response in Aspergillus nidulans

The Mre11-Rad50-Nbs1 protein complex has emerged as a central player in the cellular DNA damage response. Mutations in scaANBS1, which encodes the apparent homologue of human Nbs1 in Aspergillus nidulans, inhibit growth in the presence of the anti-topoisomerase I drug camptothecin. We have used the scaANBS1 cDNA as a bait in a yeast two-hybrid screening and report the identification of the A. nidulans Mre11 homologue (mreA). The inactivated mreA strain was more sensitive to several DNA damaging and oxidative stress agents. Septation in A. nidulans is dependent not only on the uvsBATR gene, but also on the mre11 complex. scaANBS1 and mreA genes are both involved in the DNA replication checkpoint whereas mreA is specifically involved in the intra-S-phase checkpoint. ScaANBS1 also participates in G2-M checkpoint control upon DNA damage caused by MMS. In addition, the scaANBS1 gene is also important for ascospore viability, whereas mreA is required for successful meiosis in A. nidulans. Consistent with this view, the Mre11 complex and the uvsCRAD51 gene are highly expressed at the mRNA level during the sexual development.     

Effects of UVB radiation on the carragenophyte <Emphasis Type="Italic">Kappaphycus alvarezii</Emphasis> (Rhodophyta,Gigartinales): changes in ultrastructure,growth, and photosynthetic pigments

Damage to the ozone layer has led to increased levels of ultraviolet radiation at the earth’s surface. Increased ultraviolet radiation can affect macroalgae in many important ways, including reduced growth rate, changes in cell biology and ultrastructure. Kappaphycus alvarezii is a red macroalga of economic interest due to its production of kappa carrageenan. In this study, we examined two strains of K. alvarezii (green and red) exposed to ultraviolet B radiation (UVBR) for 3 h per day during 28 days of cultivation in vitro. UVBR caused changes in the ultrastructure of cortical and subcortical cells, which included increased thickness of the cell wall and plastoglobuli, reduced intracellular spaces, changes in the cell contour, and destruction of chloroplast internal organization. While the green strain exposed to photosynthetically active radiation (PAR) showed growth rates of 6.75% day⁻¹, the red strain grew only 6.35% day⁻¹. Upon exposure to PAR + UV-B, a decreasing trend in growth rates was observed for both strains, with the green strain growing 3.0% day⁻¹ and the red strain growing 2.77% day⁻¹. Significant differences in growth rates between control and UV-B-exposed algae were also found in both strains. Furthermore, compared with control algae, phycobiliprotein contents (phycoerythrin, phycocyanin, and allophycocyanin) were observed to decrease in both strains after PAR + UV-B exposure. However, while the chlorophyll a levels increased in both strains, the green strain showed no significant differences in chlorophyll a levels. Taken together, these findings strongly suggested that UVBR negatively affects the ultrastructure, growth rates, and photosynthetic pigments of intertidal macroalgae and, in the long term, their economic viability.     

Changes in ultrastructure and cytochemistry of the agarophyte Gracilaria domingensis (Rhodophyta, Gracilariales) treated with cadmium

The agarophyte macroalgae Gracilaria domingensis (Kützing) Sonder ex Dickie is widely distributed along the Brazilian coast. While this species produces agarana, it is more important in the human diet. Therefore, the present study aimed to evaluate the biological effects of cadmium on its morphology and cellular organization. To accomplish this, the effects of cadmium in apical segments of G. domingensis were examined in vitro. Over a period of 16 days, the segments were cultivated and exposed to photosynthetically active radiation (PAR) at 80 μmol photons m^?2 s^?1, with cadmium treatments in doses of 100, 200 and 300 μM. The samples were processed for light, transmission and scanning electron microscopy. Histochemical analyses included Toluidine Blue for acidic polysaccharides, Coomassie Brilliant Blue for total protein, and Periodic Acidic Schiff for neutral polysaccharides. In all cadmium treatments, cytochemical analysis showed 1) metachromatic granulation in vacuole and lenticular thickness of the cell wall, 2) a higher concentration of cytoplasmic organelles, and 3) an increase in the number of floridean starch grains. Cadmium also caused changes in the ultrastructure of cortical and subcortical cells, including increased cell wall thickness and vacuole volume, as well as the destruction of chloroplast internal organization and increased number of plastoglobuli. In addition, treated plants showed a gradual increase in surface roughness, apparently the result of cadmium absorption. Taken together, these findings strongly suggested that cadmium negatively affects the agarophyte G. domingensis, posing a threat to the vitality of this plant species as a supplement in the human diet.     

Preventive and therapeutic euphol treatment attenuates experimental colitis in mice

Background

The tetracyclic triterpene euphol is the main constituent found in the sap of Euphorbia tirucalli. This plant is widely known in Brazilian traditional medicine for its use in the treatment of several kinds of cancer, including leukaemia, prostate and breast cancers. Here, we investigated the effect of euphol on experimental models of colitis and the underlying mechanisms involved in its action.

Methodology/Principal Findings

Colitis was induced in mice either with dextran sulfate sodium (DSS) or with 2,4,6-trinitrobenzene sulfonic acid (TNBS), and the effect of euphol (3, 10 and 30 mg/kg) on colonic injury was assessed. Pro-inflammatory mediators and cytokines were measured by immunohistochemistry, enzyme-Linked immunoabsorbent assay (ELISA), real time-polymerase chain reaction (RT-PCR) and flow cytometry. Preventive and therapeutic oral administration of euphol attenuated both DSS- and TNBS-induced acute colitis as observed by a significant reduction of the disease activity index (DAI), histological/microscopic damage score and myeloperoxidase (MPO) activity in colonic tissue. Likewise, euphol treatment also inhibited colon tissue levels and expression of IL-1β, CXCL1/KC, MCP-1, MIP-2, TNF-α and IL-6, while reducing NOS2, VEGF and Ki67 expression in colonic tissue. This action seems to be likely associated with inhibition of activation of nuclear factor-κB (NF-κB). In addition, euphol decreased LPS-induced MCP-1, TNF-α, IL-6 and IFN-γ, but increased IL-10 secretion from bone marrow-derived macrophages in vitro. Of note, euphol, at the same schedule of treatment, markedly inhibited both selectin (P- and E-selectin) and integrin (ICAM-1, VCAM-1 and LFA-1) expression in colonic tissue.

Conclusions/Significance

Together, these results clearly demonstrated that orally-administered euphol, both preventive or therapeutic treatment were effective in reducing the severity of colitis in two models of chemically-induced mouse colitis and suggest this plant-derived compound might be a potential molecule in the management of inflammatory bowel diseases.     

Effects of salinity on the growth rate,carrageenan yield,and cellular structure of <Emphasis Type=Italic>Kappaphycus alvarezii</Emphasis> (Rhodophyta,Gigartinales) cultured in vitro

Kappaphycus alvarezii was cultured in vitro under salinities ranging from 15 to 55 psu for 35 days to determine the differential effect on growth rate, carrageenan yield, and cellular structure. Plants kept in 15 psu died after 3 days, while plants cultured in 55 psu presented low growth rates during the entire experimental period (0.28% day⁻¹). Plants cultured in 25, 35, and 45 psu showed growth rates normally associated with this species (between 3% and 4% day⁻¹) and similar cellular morphology. Carrageenan yield was significantly higher in plants cultured in 25 psu in relation to the other treatments. As observed by light microscopy, plants cultured in 15 psu showed cellular turgidity and increased cell wall thickness, both consequences of hyposalinity. Chloroplasts and other membranous organelles underwent rupture and considerable disorganization in ultrastructure. Although branches from the 55 psu samples showed plasmolysis, cells were able to maintain chloroplast integrity, despite their rudimentary features. In high salinities, great concentrations of floridean starch grains were observed in subcortical cells, indicating their probable participation in osmoregulation. Based on these results, we defined the range of 25 to 45 psu as the limits of saline tolerance for K. alvarezii. While new field studies are required to confirm these results, it can be concluded that new sites, such as inactive or abandoned shrimp tanks with salinities up to 25 psu, could be considered for commercial farming.     

sbmC, a stationary-phase induced SOS Escherichia coli gene, whose product protects cells from the DNA replication inhibitor microcin B17

Microcin B17 (MccB17) is a ribosomally synthesized peptide antibiotic of 43 amino acids that induces double-strand breaking of DNA in a DNA gyrase-dependent reaction. As a consequence, the SOS regulon is induced and massive DNA degradation occurs. In this work we have characterized an Escherichia coli gene, sbmC , that in high copy number determines high cell resistance to MccB17. sbmC encodes a cytoplasmic polypeptide of 157 amino acids ( M_r , 18 095) that has been visualized in SDS—polyacrylamide gels. The gene is located at min 44 of the E. coli genetic map, close to the sbcB gene. sbmC expression is induced by DNA-damaging agents and, also, by the entry of cells into the stationary growth phase. A G → T transversion at the fifth nucleotide of the quasicanonical LexA-box preceding the gene makes recA cells 16-fold more resistant to exogenous MccB17. The gene product, SbmC, also blocks MccB17 export from producing cells. Altogether, our results suggest that SbmC recognizes and sequesters MccB17 in a reversible way.     

Whole-exome sequencing reveals insights into genetic susceptibility to Congenital Zika Syndrome

Congenital Zika Syndrome (CZS) is a critical illness with a wide range of severity caused by Zika virus (ZIKV) infection during pregnancy. Life-threatening neurodevelopmental dysfunctions are among the most common phenotypes observed in affected newborns. Risk factors that contribute to susceptibility and response to ZIKV infection may be related to the virus itself, the environment, and maternal genetic background. Nevertheless, the newborn’s genetic contribution to the critical illness is still not elucidated. Here, we aimed to identify possible genetic variants as well as relevant biological pathways that might be associated with CZS phenotypes. For this purpose, we performed a whole-exome sequencing in 40 children born to women with confirmed exposure to ZIKV during pregnancy. We investigated the occurrence of rare harmful single-nucleotide variants (SNVs) possibly associated with inborn errors in genes ontologically related to CZS phenotypes. Moreover, an exome-wide association analysis was also performed using a case-control design (29 CZS cases and 11 controls), for both common and rare variants. Five out of the 29 CZS patients harbored known pathogenic variants likely to contribute to mild to severe manifestations observed. Approximately, 30% of affected individuals carried at least one pathogenic or likely pathogenic SNV in genes candidates to play a role in CZS. Our common variant association analysis detected a suggestive protective effect of the rs2076469 in DISP3 gene (p-value: 1.39 x 10⁻⁵). The IL12RB2 gene (p-value: 2.18x10^-11) also showed an unusual distribution of nonsynonymous rare SNVs in control samples. Finally, genes harboring harmful variants are involved in processes related to CZS phenotypes such as neurological development and immunity. Therefore, both rare and common variations may be likely to contribute as the underlying genetic cause of CZS susceptibility. The variations and pathways identified in this study may also have implications for the development of therapeutic strategies in the future.