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We consider various problems regarding roots and coincidence points for maps into the Klein bottle . The root problem where the target is and the domain is a compact surface with non-positive Euler characteristic is studied. Results similar to those when the target is the torus are obtained. The Wecken property for coincidences from to is established, and we also obtain the following 1-parameter result. Families which are coincidence free but any homotopy between and , , creates a coincidence with . This is done for any pair of maps such that the Nielsen coincidence number is zero. Finally, we exhibit one such family where is the constant map and if we allow for homotopies of , then we can find a coincidence free pair of homotopies.

Breast cancer is the most common type of cancer and the leading cause of cancer mortality among women worldwide. Considering the limitations of the current treatments available, we analyzed the in vitro cytotoxic potential of ((4-Fluoro-phenyl)-{2-[(1-phenyl-9H-β-carboline-3-carbonyl)-amino]-ethylamino}-methyl)-phosphonic acid dibutyl ester ( BCP-1 ) in breast cancer cells (MCF-7 and MDA-MB-231) and in a non-tumor breast cell line (MCF-10A). BCP-1 has an α-aminophosphonate unit linked to the β-carboline nucleus, and the literature indicates that compounds of these classes have high biological potential. In the present study, the mechanism of action of BCP-1 was investigated through methods of spectrofluorimetry, flow cytometry, and protein expression analysis. It was found that BCP-1 inhibited the proliferation of both cancer cell lines. Furthermore, it induced oxidative stress and cell cycle arrest in G2/M. Upregulation of apoptosis-related proteins such as Bax, cytochrome C, and caspases, as well as a decrease in the anti-apoptotic protein Bcl-2, indicated potential induction of apoptosis in the MDA-MB-231 cells. While in MCF-7 cells, BCP-1 activated the autophagic death pathway, which was demonstrated by an increase in autophagic vacuoles and acidic organelles, in addition to increased expression of LC3I/LC3II and reduced SQSTM1/p62 expression. Further, BCP-1 demonstrated antimetastatic potential by reducing MMP-9 expression and cell migration in both breast cancer cell lines. In conclusion, BCP-1 is a promising candidate for breast cancer chemotherapy.

First-generation ethanol (E1G) is based on the fermentation of sugars released from saccharine or starch sources, while second-generation ethanol (E2G) is focused on the fermentation of sugars released from lignocellulosic feedstocks. During the fractionation process to release sugars from hemicelluloses (mainly xylose), some inhibitor compounds are released hindering fermentation. Thus, the biggest challenge of using hemicellulosic hydrolysate is selecting strains and processes able to efficiently ferment xylose and tolerate inhibitors. With the aim of diluting inhibitors, sugarcane molasses (80% of sucrose content) can be mixed to hemicellulosic hydrolysate in an integrated E1G-E2G process. Cofermentations of xylose and sucrose were evaluated for the native xylose consumer Spathaspora passalidarum and a recombinant Saccharomyces cerevisiae strain. The industrial S. cerevisiae strain CAT-1 was modified to overexpress the XYL1, XYL2 and XKS1 genes and a mutant ([4-59Δ]HXT1) version of the low-affinity HXT1 permease, generating strain MP-C5H1. Although S. passalidarum showed better results for xylose fermentation, this yeast showed intracellular sucrose hydrolysis and low sucrose consumption in microaerobic conditions. Recombinant S. cerevisiae showed the best performance for cofermentation, and a batch strategy at high cell density in bioreactor achieved unprecedented results of ethanol yield, titer and volumetric productivity in E1G-E2G production process., (© The Author(s) 2021. Published by Oxford University Press on behalf of FEMS. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Cells are continuously subject to various stresses, battling both exogenous insults as well as toxic by-products of normal cellular metabolism and nutrient deprivation. Throughout the millennia, cells developed a core set of general stress responses that promote survival and reproduction under adverse circumstances. Past and current research efforts have been devoted to understanding how cells sense stressors and how that input is deciphered and transduced, resulting in stimulation of stress management pathways. A prime element of cellular stress responses is the increased transcription and translation of proteins specialized in managing and mitigating distinct types of stress. In this review, we focus on recent developments in our understanding of cellular sensing of proteotoxic stressors that impact protein synthesis, folding, and maturation provided by the model eukaryote the budding yeast, Saccharomyces cerevisiae, with reference to similarities and differences with other model organisms and humans., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: Since uptake of xylose limits its fermentation, we aimed to identify novel sugar transporters from Scheffersomyces stipitis that allow xylose uptake and fermentation by engineered Saccharomyces cerevisiae., Results: An hxt-null S. cerevisiae strain, lacking the major hexose transporters (hxt1Δ-hxt7Δ and gal2Δ) but having high xylose reductase, xylitol dehydrogenase and xylulokinase activities, was transformed with a genomic DNA library from S. stipitis. Four plasmids allowing growth on xylose contained three genes encoding sugar transporters: the previously characterized XUT1 permease, and two new genes (HXT2.6 and QUP2) not previously identified as xylose transporters. High cell density fermentations with the recombinant strains showed that the XUT1 gene allowed ethanol production from xylose or xylose plus glucose as carbon sources, while the HXT2.6 permease produced both ethanol and xylitol, and the strain expressing the QUP2 gene produced mainly xylitol during xylose consumption., Conclusions: Cloning novel sugar transporters not previously identified in the S. stipitis genome using an hxt-null S. cerevisiae strain with a high xylose-utilizing pathway provides novel promising target genes for improved lignocellulosic ethanol production by yeasts.

The use of clays for therapeutic practice is widespread in almost all regions of the world. In this study the physicochemical and microbiological healing characteristics of a clay from Ocara, Brazil, popularly used for therapeutic uses, were analyzed. The presence of Ca, Mg, Al, Fe, and Si was observed, which initially indicated that the clay had potential for therapeutic use. The average particle size of the clay (26.3 μm) can induce the microcirculation of the skin and the XRD analysis shows that the clay is formed by kaolinite and illite, a swelling clay. During the microbiological evaluation there was the need to sterilize the clay for later incorporation into the pharmaceutical formula. The accelerated stability test at 50°C for 3 months has showed that the pharmaceutical formula remained stable with a shelf life of two years. After the stability test the wound-healing capacity of the formulation in rats was evaluated. It was observed that the treatment made with the formulation containing the Ocara clay showed the best results since the formula allowed greater formation of collagen fibers and consequent regeneration of the deep dermis after seven days of treatment and reepithelialization and continuous formation of granulation tissue at the 14th day., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Since the uptake of xylose is believed to be one of the rate-limiting steps for xylose ethanol fermentation by recombinant Saccharomyces cerevisiae strains, we transformed a hxt-null strain lacking the major hexose transporters (hxt1Δ-hxt7Δ and gal2Δ) with an integrative plasmid to overexpress the genes for xylose reductase (XYL1), xylitol dehydrogenase (XYL2) and xylulokinase (XKS1), and analyzed the impact that overexpression of the HXT1, HXT2, HXT5 or HXT7 permeases have in anaerobic batch fermentations using xylose, glucose, or xylose plus glucose as carbon sources. Our results revealed that the low-affinity HXT1 permease allowed the maximal consumption of sugars and ethanol production rates during xylose/glucose co-fermentations, but was incapable to allow xylose uptake when this sugar was the only carbon source. The moderately high-affinity HXT5 permease was a poor glucose transporter, and it also did not allow significant xylose uptake by the cells. The moderately high-affinity HXT2 permease allowed xylose uptake with the same rates as those observed during glucose consumption, even under co-fermentation conditions, but had the drawback of producing incomplete fermentations. Finally, the high-affinity HXT7 permease allowed efficient xylose fermentation, but during xylose/glucose co-fermentations this permease showed a clear preference for glucose. Thus, our results indicate that approaches to engineer S. cerevisiae HXT transporters to improve second generation bioethanol production need to consider the composition of the biomass sugar syrup, whereby the HXT1 transporter seems more suitable for hydrolysates containing xylose/glucose blends, whereas the HXT7 permease would be a better choice for xylose-enriched sugar streams., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The draft genome sequence of the yeast Spathaspora arborariae UFMG-HM19.1A(T) (CBS 11463 = NRRL Y-48658) is presented here. The sequenced genome size is 12.7 Mb, consisting of 41 scaffolds containing a total of 5,625 predicted open reading frames, including many genes encoding enzymes and transporters involved in d-xylose fermentation.

In the last decades, a series of compounds, including quinones and polyphenols, has been described as having anti-fibrillogenic action on α-synuclein (α-syn) whose aggregation is associated to the pathogenesis of Parkinson's disease (PD). Most of these molecules act as promiscuous anti-amyloidogenic agents, interacting with the diverse amyloidogenic proteins (mostly unfolded) through non-specific hydrophobic interactions. Herein we investigated the effect of the vitamins K (phylloquinone, menaquinone and menadione), which are 1,4-naphthoquinone (1,4-NQ) derivatives, on α-syn aggregation, comparing them with other anti-fibrillogenic molecules such as quinones, polyphenols and lipophilic vitamins. Vitamins K delayed α-syn fibrillization in substoichiometric concentrations, leading to the formation of short, sheared fibrils and amorphous aggregates, which are less prone to produce leakage of synthetic vesicles. In seeding conditions, menadione and 1,4-NQ significantly inhibited fibrils elongation, which could be explained by their ability to destabilize preformed fibrils of α-syn. Bidimensional NMR experiments indicate that a specific site at the N-terminal α-syn (Gly31/Lys32) is involved in the interaction with vitamins K, which is corroborated by previous studies suggesting that Lys is a key residue in the interaction with quinones. Together, our data suggest that 1,4-NQ, recently showed up by our group as a potential scaffold for designing new monoamine oxidase inhibitors, is also capable to modulate α-syn fibrillization in vitro., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

DNA is the biopolymer most studied by scanning probe methods, and it is now possible to obtain reliable and reproducible images of DNA using atomic force microscopy (AFM). AFM has been extensively used to elucidate morphological changes to DNA structure, such as the formation of knots, nicks, supercoiling and bends. The mitochondrial or kinetoplast DNA (kDNA) of trypanosomatids is the most unusual DNA found in nature, being unique in organization and replication. The kDNA is composed of thousands of topologically interlocked DNA circles that form a giant network. To understand the biological significance of the kinetoplast DNA, it is necessary to learn more about its structure. In the present work, we used two procedures to prepare kDNA networks of Crithidia fasciculata for observation by AFM. Because AFM allows for the examination of kDNA at high resolution, we were able to identify regions of overlapping kDNA molecules and sites where several molecules cross. This found support the earlier described kDNA structural organization as composed by interlocked circles. We also observed an intricate high-density height pattern around the periphery of the network of C. fasciculata, which appears to be a bundle of DNA fibers that organizes the border of the network. Our present data confirm that AFM is a powerful tool to study the structural organization of biological samples, including complex arrays of DNA such as kDNA, and can be useful in revealing new details of structures previously visualized by other means., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Four strains of a new yeast species were isolated from rotting wood from two sites in an Atlantic Rain Forest and a Cerrado ecosystem in Brazil. The analysis of the sequences of the D1/D2 domains of the large-subunit rRNA gene showed that this species belongs to the Spathaspora clade. The new species ferments D-xylose efficiently and is related to Candida jeffriesii and Spathaspora passalidarum, both of which also ferment D-xylose. Similar to S. passalidarum, the new species produces unconjugated asci with a single greatly elongated ascospore with curved ends. The type strain of Spathaspora arborariae sp. nov. is UFMG-HM19.1A(T) (=CBS11463(T)=NRRL Y-48658(T)).

Cidofovir (CDV) is one of the most effective antiorthopoxvirus drugs, and it is widely accepted that viral DNA replication is the main target of its activity. In the present study, we report a detailed analysis of CDV effects on the replicative cycles of distinct vaccinia virus (VACV) strains: Cantagalo virus, VACV-IOC, and VACV-WR. We show that despite the approximately 90% inhibition of production of virus progeny, virus DNA accumulation was reduced only 30%, and late gene expression and genome resolution were unaltered. The level of proteolytic cleavage of the major core proteins was diminished in CDV-treated cells. Electron microscopic analysis of virus-infected cells in the presence of CDV revealed reductions as great as 3.5-fold in the number of mature forms of virus particles, along with a 3.2-fold increase in the number of spherical immature particles. A detailed analysis of purified virions recovered from CDV-treated cells demonstrated the accumulation of unprocessed p4a and p4b and nearly 67% inhibition of DNA encapsidation. However, these effects of CDV on virus morphogenesis resulted from a primary effect on virus DNA synthesis, which led to later defects in genome encapsidation and virus assembly. Analysis of virus DNA by atomic force microscopy revealed that viral cytoplasmic DNA synthesized in the presence of CDV had an altered structure, forming aggregates with increased strand overlapping not observed in the absence of the drug. These aberrant DNA aggregations were not encapsidated into virus particles.