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Resumen Documentamos por primera vez para el departamento del Tolima, Colombia, la presencia de 22 especies de plantas vasculares sin semilla, principalmente como resultado de la revisión de los especímenes del herbario de la Universidad de Caldas (FAUC). Para ocho de estas especies se amplía su rango de distribución altitudinal. Destacamos la especie endémica Luisma bivascularis (Polypodiaceae) por ampliar su distribución geográfica y altitudinal, pues se consideraba restringida a su localidad tipo, y porque se registró un nuevo hábito para ella. Abstract The presence of 22 species of seed-free vascular plants is documented for the first time in the department of Tolima, Colombia, mainly as a result of the revision of specimens in the herbarium of the Universidad de Caldas (FAUC). Eight of these species extended their range of altitudinal distribution. The endemic species Luisma bivascularis (Polypodiaceae) is highlighted due the extension of its geographic and elevational distributions, previously restricted to its type locality, and because a new habit was recorded for it.

Los bosques de encino son importantes en el equilibrio de los ecosistemas donde estos cohabitan, ya que son un grupo de especies con mayor capacidad para fijar y almacenar carbono atmosférico. El objetivo de este trabajo fue desarrollar ecuaciones alométricas para estimar biomasa aérea de seis especies de encino (Quercus rugosa, Q. obtusata, Q. sideroxyla, Q. coccolobifolia, Q. laurina y Q. candicans) con un muestreo destructivo de 165 árboles. Se ajustaron ecuaciones para estimar biomasa por componentes estructurales (fuste, ramas y follaje), y de forma aditiva se estimó la biomasa total, así como una ecuación generalizada para las seis especies, y ecuaciones para estas divididas en dos grupos. Para mejorar la capacidad predictiva de las ecuaciones se ajustaron modelos que incluyen las variables de diámetro normal, altura total y densidad de la madera. El mayor porcentaje de biomasa se concentró en el fuste con 60.6%, mientras que ramas y follaje representaron 36.1% y 3.28%, respectivamente. Las ecuaciones ajustadas explicaron más de 95% de la variabilidad en la biomasa total del árbol y, comparadas con ecuaciones desarrolladas en otros lugares para el mismo género, presentaron un menor sesgo porcentual. Las ecuaciones alométricas generadas pueden ser utilizadas para la región, así como en bosques con características estructurales y de crecimiento similares a las de las comunidades de encino de la sierra de Guanajuato.

The cell wall is a structure external to the plasma membrane that is essential for the survival of the fungi. This polysaccharidic structure confers resistance to the cell internal turgor pressure and protection against mechanical injury. The fungal wall is also responsible for the shape of these organisms due to different structural polysaccharides, such as β-(1,3)-glucan, which form fibers and confer rigidity to the cell wall. These polysaccharides are not present in animal cells and therefore they constitute excellent targets for antifungal chemotherapies. Cell wall damage leads to the activation of MAPK signaling pathways, which respond to the damage by activating the repair of the wall and the maintenance of the cell integrity. Fission yeast Schizosaccharomyces pombe is a model organism for the study morphogenesis, cell wall, and how different inputs might regulate this structure. We present here a short overview of the fission yeast wall composition and provide information about the main biosynthetic activities that assemble this cell wall. Additionally, we comment the recent advances in the knowledge of the cell wall functions and discuss the role of the cell integrity MAPK signaling pathway in the regulation of fission yeast wall., This work was supported by grants BIO2015-69958-P and BFU2017-82423-P from MINECO, Spain and CSI068P17 from Junta de Castilla y León.

Cytokinesis is the final process of the vegetative cycle, which divides a cell into two independent daughter cells once mitosis is completed. In fungi, as in animal cells, cytokinesis requires the formation of a cleavage furrow originated by constriction of an actomyosin ring which is connected to the plasma membrane and causes its invagination. Additionally, because fungal cells have a polysaccharide cell wall outside the plasma membrane, cytokinesis requires the formation of a septum coincident with the membrane ingression. Fission yeast Schizosaccharomyces pombe is a unicellular, rod-shaped fungus that has become a popular model organism for the study of actomyosin ring formation and constriction during cell division. Here we review the current knowledge of the septation and separation processes in this fungus, as well as recent advances in understanding the functional interaction between the transmembrane enzymes that build the septum and the actomyosin ring proteins.

Background: Phytolacca tetramera is an endemic plant from Argentina that is currently at serious risk because its environment is subjected to a high anthropic impact. A previous study has shown that berry extracts obtained from this plant display antifungal activity against multiple human-pathogenic fungi when tested with a non-standardized method. Further evidences of the antifungal properties of other parts of the plant and studies of mechanism of antifungal action of the antifungal chemically characterized extracts are required. Purpose: This study aimed to gain further evidence of the antifungal activity of P. tetramera berry, leaf and root extracts in order to find the most active extract to be developed as an Herbal Medicinal Antifungal Product. The medicinal usefulness of P. tetramera extracts as antifungal agents will serve as an important support to create concience and carry out actions tending to the preservation of this threatened species and its environment. Materials and methods: Chemical analysis of all P. tetramera extracts, including quantitation of selected markers, was performed through UHPLC-ESI-MS/MS and UPLC-ESI-MS techniques according to the European Medicines Agency (EMA). The antifungal activity of the quantified extracts was tested with the standardized CLSI microbroth dilution method against Candida spp. Antifungal mechanisms of the most active extract were studied by examination of morphological changes by phase-contrast and fluorescence microscopies and both, cellular and enzymatic assays targeting either the fungal membrane or the cell wall. Results: The antifungal activity of twelve P. tetramera extracts was tested against Candida albicans and Candida glabrata. The dichloromethane extract from berries (PtDEb) showed the best activity. Phytolaccagenin (PhytG) and phytolaccoside B (PhytB) were selected as the main active markers for the antifungal P. tetramera extracts. The quantitation of these active markers in all extracts showed that PtDEb possessed the highest amount of PhytG and PhytB. Finally, studies on the mechanism of antifungal action showed that the most active PtDEb extract produces morphological changes compatible with a damage of the cell wall and/or the plasma membrane. Cellular and enzymatic assays showed that PtDEb would not damage the fungal cell wall by itself, but would alter the plasma membrane. In agreement, PtDEb was found to bind to ergosterol, the main sterol of the fungal plasma membrane. Conclusion: Studies of the anti-Candida activity of P. tetramera extracts led to the selection of PtDEb as the most suitable extract, confirming the antifungal properties of the threatened species P. tetramera. The new data give a valuable reason for the definitive protection of this sp. and its natural environment thus allowing further studies for the future development of an Herbal Medicinal Antifungal Product., Susana A. Zacchino and Laura Svetaz (L.S.) acknowledge Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), PICT2014-1170 and PICT2016-1833 and National University of Rosario, Argentina (UNR) for funds. J.C.R. acknowledges MINECO (BIO2015-69958-P), Junta de Castilla y León/FEDER (CSI068P17 and >Escalera de Excelencia> CLU-2017-03), Spain, for funds. Estefanía Butassi (E.B.) acknowledges Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) for doctoral and post-doctoral fellowships. L.S. is a member of the CONICET Researcher career; L.S. and E.B. belong to the teaching staff of Pharmacognosy area. Jean-Luc Wolfender and Shuaizhen Zhou (S.Z.) acknowledge Sino Swiss Science and Technology Cooperation Program (SSSTC) IP18-092011 for the funding of the post-doctoral stay of S.Z. The MEDINA authors Francisca Vicente, Caridad Díaz and José Pérez-del Palacio disclosed the receipt of financial support from Fundación MEDINA, a public-private partnership of Merck Sharp & Dohme de España S.A./Universidad de Granada/Junta de Andalucía, Spain.

This is an open access article distributed under the terms of the Creative Commons Attribution License.-- et al., Cytokinesis in many organisms requires a plasma membrane anchored actomyosin ring, whose contraction facilitates cell division. In yeast and fungi, actomyosin ring constriction is also coordinated with division septum assembly. How the actomyosin ring interacts with the plasma membrane and the plasma membrane-localized septum synthesizing machinery remains poorly understood. In Schizosaccharomyces pombe, an attractive model organism to study cytokinesis, the β-1,3-glucan synthase Cps1p / Bgs1p, an integral membrane protein, localizes to the plasma membrane overlying the actomyosin ring and is required for primary septum synthesis. Through a high-dosage suppressor screen we identified an essential gene, sbg1 (suppressor of beta glucan synthase 1), which suppressed the colony formation defect of Bgs1-defective cps1-191 mutant at higher temperatures. Sbg1p, an integral membrane protein, localizes to the cell ends and to the division site. Sbg1p and Bgs1p physically interact and are dependent on each other to localize to the division site. Loss of Sbg1p results in an unstable actomyosin ring that unravels and slides, leading to an inability to deposit a single contiguous division septum and an important reduction of the β-1,3-glucan proportion in the cell wall, coincident with that observed in the cps1-191 mutant. Sbg1p shows genetic and / or physical interaction with Rga7p, Imp2p, Cdc15p, and Pxl1p, proteins known to be required for actomyosin ring integrity and efficient septum synthesis. This study establishes Sbg1p as a key member of a group of proteins that link the plasma membrane, the actomyosin ring, and the division septum assembly machinery in fission yeast., MB was supported by Core funds from Temasek Life Sciences Laboratory (http://www.tll.org.sg), Wellcome Trust SIA (WT101885MA) (www.wellcome.ac.uk) and a Royal Society Wolfson Merit Award (https://royalsociety.org/). NIN was supported by Core funds from Temasek Life Sciences Laboratory (http://www.tll.org.sg). JCR was supported by Spanish Ministry of Science and Innovation (BIO2012-35372 and BIO2015-69958-P). MO was supported by Bio-imaging Center (S0991205) of Japan Women’s University established as a private university in Japan with the support of Ministry of Education, Culture, Sports Science and Technology (http://www.jiirs.org).

In animal cells cytokinesis relies on the contraction of an actomyosin ring that pulls the plasma membrane to create a cleavage furrow, whose ingression finally divides the mother cell into two daughter cells. Fungal cells are surrounded by a tough and flexible structure called cell wall, which is considered to be the functional equivalent of the extracellular matrix in animal cells. Therefore, in addition to cleavage furrow ingression, fungal cytokinesis also requires the centripetal formation of a septum wall structure that develops between the dividing cells, whose genesis must be strictly coordinated with both the actomyosin ring closure and plasma membrane ingression. Here we briefly review what is known about the septum structure and composition in the fission yeast Schizosaccharomyces pombe, the recent progress about the relationship between septum biosynthesis and actomyosin ring constriction, and the importance of the septum and ring in the steady progression of the cleavage furrow., This work was supported by the Spanish Ministry of Science and Innovation (BFU2010-15641 and BFU2013-39394-P) to PP. JCR was financed by the Spanish Ministry of Science and Innovation (BIO2012-35372 and BIO2015-69958-P), and the Junta de Castilla y León, Spain (CSI037U14). JCGC was supported by a Juan de la Cierva postdoctoral contract from the Spanish Ministry of Science and Innovation.

Fungal cleavage furrow formation during cytokinesis relays in the coordinated contraction of an actomyosinbased ring and the centripetal synthesis of both new plasma membrane and a special wall structure named division septum. Through transmission electron microscopy, the septum exhibits a three-layered structure with a central primary septum, fl anked at both sides by the secondary septum. In contrast to the chitinous primary septum present in most of fungi, the fi ssion yeast Schizosaccharomyces pombe does not contain chitin, instead it divides through the formation of a linear β(1,3)glucan-rich primary septum, which has been shown to be specifi cally stained by the fl uorochrome Calcofl uor white. Recent fi ndings in S. pombe have revealed the importance of septum synthesis for the steady contraction of the ring during cytokinesis. Therefore, to study the molecular mechanisms that connect the extracellular septum wall with the other components of the cytokinetic machinery located in the plasma membrane and cytoplasm, new experimental approaches are needed. Here we describe the methods developed to image the septum structure by fl uorescence microscopy, with a special focus in the analysis of septum progression by the use of time-lapse microscopy.

13 páginas, 7 figuras, 5 tablas.-- El pdf del artículo es la versión post-print., Three specific β(1,3)glucan synthase (GS) inhibitor families, papulacandins, acidic terpenoids, and echinocandins, have been analyzed in Schizosaccharomyces pombe wild-type and papulacandin-resistant cells and GS activities. Papulacandin and enfumafungin produced similar in vivo effects, different from that of echinocandins. Also, papulacandin was the strongest in vitro GS inhibitor (IC50 103–104-fold lower than with enfumafungin or pneumocandin), but caspofungin was by far the most efficient antifungal because of the following. 1) It was the only drug that affected resistant cells (minimal inhibitory concentration close to that of the wild type). 2) It was a strong inhibitor of wild-type GS (IC50 close to that of papulacandin). 3) It was the best inhibitor of mutant GS. Moreover, caspofungin showed a special effect for two GS inhibition activities, of high and low affinity, separated by 2 log orders, with no increase in inhibition. pbr1-8 and pbr1-6 resistances are due to single substitutions in the essential Bgs4 GS, located close to the resistance hot spot 1 region described in Saccharomyces and Candida Fks mutants. Bgs4pbr1-8 contains the E700V change, four residues N-terminal from hot spot 1 defining a larger resistance hot spot 1-1 of 13 amino acids. Bgs4pbr1-6 contains the W760S substitution, defining a new resistance hot spot 1-2. We observed spontaneous revertants of the spherical pbr1-6 phenotype and found that an additional A914V change is involved in the recovery of the wild-type cell shape, but it maintains the resistance phenotype. A better understanding of the mechanism of action of the antifungals available should help to improve their activity and to identify new antifungal targets., This work was supported in part by Grants BIO2006-13566 from Ministerio de Educación y Ciencia, BIO2009-10597 from Ministerio de Ciencia e Innovación, and GR231 from Junta de Castilla y León, Spain. Supported by a fellowship from Fundaçâo para a Ciência e a Tecnologia, Portugal. Supported by a fellowship from Consejo Superior de Investigaciones Científicas, Spain. Supported by a fellowship from Junta de Castilla y León, Spain. Supported by a fellowship from Ministerio de Ciencia e Innovación, Spain.

Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to animals and humans. Poultry litter is frequently used as a food supplement for ruminants, and when poultry feed contains AF, the litter becomes contaminated as well, thus having an effect on livestock health. This study identified and quantified AF (AFB(1), AFB(2), AFG(1), and AFG(2)) from poultry feed and their recovery, together with their metabolites (AFM(1), AFM(2), AFP(1), and aflatoxicol) in litter. An experiment with 25 Hy-Line W-36 hens, in their second production stage, 121 wk old, was carried out. Hens were distributed in 3 groups placed in individual cages and 1 ration of 250 g of feed was given to each hen daily. Nine hens of the control group were fed with clean feed, without AFB(1); the other 2 experimental groups, with 8 hens each, were fed with 2 AFB(1) concentrations: 30 and 500 microg.kg(-1). The feed was replaced and weighed daily throughout a 7-d period to register the amount of feed consumed by the hens. Litter from each hen was collected, weighed, and dried individually. The chemical analysis of 40 g of each one of the 200 feed and 200 litter samples was chemically extracted and concentrated with immunoaffinity columns for total AF. To quantify AF, calibration curves for each AF were done by HPLC. Feed samples of the 3 groups presented significant difference with AFB(2) and AFG(2), whereas in litter samples, there were significant differences for AFG(2) in the 500 microg.kg(-1) group. Poultry litter had traces of AFM(1), AFM(2), AFP(1), and AFL with no significant differences among treatments. Aflatoxin B(1) prevalence in litter samples can cause damages in livestock because this mycotoxin reduces the digestibility of ruminant feed up to 67%.

The cps5 - 138 fission yeast mutant shows an abnormal lemon-like morphology at 28°C in minimal medium and a lethal thermosensitive phenotype at 37°C. Cell growth is completely inhibited at 28°C in a Ca 2+ -free medium, in which the wild type is capable of growing normally. Under these conditions, actin patches become randomly distributed throughout the cell, and defects in septum formation and subsequent cytokinesis appear. The mutant cell is hypersensitive to the cell wall-digesting enzymatic complex Novozym234 even under permissive conditions. The gene SPBC31E1.02c, which complements all the mutant phenotypes described above, was cloned and codes for the Ca 2+ -ATPase homologue Pmr1p. The gene is not essential under optimal growth conditions but is required under conditions of low Ca 2+ (35°C). The green fluorescent protein-tagged Cps5 proteins, which are expressed under physiological conditions (an integrated single copy with its own promoter in the cps5 Δ strain), display a localization pattern typical of endoplasmic reticulum proteins. Biochemical analyses show that 1,3-β- d -glucan synthase activity in the mutant is decreased to nearly half that of the wild type and that the mutant cell wall contains no detectable galactomannan when the cells are exposed to a Ca 2+ -free medium. The mutant acid phosphatase has an increased electrophoretic mobility, suggesting that incomplete protein glycosylation takes place in the mutant cells. These results indicate that S. pombe Pmr1p is essential for the maintenance of cell wall integrity and cytokinesis, possibly by allowing protein glycosylation and the polarized actin distribution to take place normally. Disruption and complementation analyses suggest that Pmr1p shares its function with a vacuolar Ca 2+ -ATPase homologue, Pmc1p (SPAPB2B4.04c), to prevent lethal activation of calcineurin for cell growth.

Schizosaccharomyces pombe Bgs1p/Cps1p has been identified as a putative (1,3)beta-D-glucan synthase (GS) catalytic subunit with a possible function during cytokinesis and polarized growth. To study this possibility, double mutants of cps1-12 and cdc septation mutants were made. The double mutants displayed several hypersensitive phenotypes and altered actin distribution. Epistasis analysis showed mutations prior to septum synthesis were dominant over cps1-12, while cps1-12 was dominant over the end of septation mutant cdc16-116, suggesting Bgs1p is involved in septum cell-wall (1,3)beta-D-glucan synthesis at cytokinesis. We have studied the in vivo physiological localization of Bgs1p in a bgs1delta strain containing a functional GFP-bgs1(+) gene (integrated single copy and expressed under its own promoter). During vegetative growth, Bgs1p always localizes to the growing zones: one or both ends during cell growth and contractile ring and septum during cytokinesis. Bgs1p localization in cdc septation mutants indicates that Bgs1p needs the medial ring and septation initiation network (SIN) proteins to localize properly with the rest of septation components. Bgs1p localization in the actin mutant cps8-188 shows it depends on actin localization. In addition, Bgs1p remains polarized in the mislocalized growing poles and septa of tea1-1 and tea2-1 mutants. During the meiotic process of the life cycle, Bgs1p localizes to the mating projection, to the cell-to-cell contact zone during cell fusion and to the neck area during zygote formation. Also, Bgs1p localization suggests that it collaborates in forespore and spore wall synthesis. During spore germination, Bgs1p localizes first around the spore during isotropic growth, then to the zone of polarized growth and finally, to the medial ring and septum. At the end of spore-cell division, the Bgs1p displacement to the old end occurs only in the new cell. All these data show that Bgs1p is localized to the areas of polarized cell wall growth and so we propose that it might be involved in synthesizing the lineal (1,3)beta-D-glucan of the primary septum, as well as a similar lineal (1,3)beta-D-glucan when other processes of cell wall growth or repair are needed.

Cytokinesis is a crucial event in the cell cycle of all living cells. In fungal cells, it requires co-ordinated contraction of an actomyosin ring and synthesis of both plasmatic membrane and a septum structure that will constitute the new cell wall end. Schizosaccharomyces pombe contains four essential putative (1,3)β-d-glucan synthase catalytic subunits, Bgs1p to Bgs4p. Here we examined the function of Bgs1p in septation by studying the lethal phenotypes of bgs1+ shut-off and bgs1Δ cells and demonstrated that Bgs1p is responsible and essential for linear (1,3)β-d-glucan and primary septum formation. bgs1+ shut-off generates a more than 300-fold Bgs1p reduction, but the septa still present large amounts of disorganized linear (1,3)β-d-glucan and partial primary septa. Conversely, both structures are absent in bgs1Δ cells, where there is no Bgs1p. The septum analysis of bgs1+-repressed cells indicates that linear (1,3)β-d-glucan is necessary but not sufficient for primary septum formation. Linear (1,3)β-d-glucan is the polysaccharide that specifically interacts with the fluorochrome Calcofluor white in fission yeast. We also show that in the absence of Bgs1p abnormal septa are formed, but the cells cannot separate and eventually die., J.C.G.C and I.M.M. acknowledge support from fellowships granted by CSIC, Spain, and FCT, Portugal respectively. This work was supported by Grants BIO2003-01040, Ministerio de Educación y Ciencia, and CSI02C05, Junta de Castilla y León, Spain, and by the Ministry of Education, Culture, Sports, Science and Technology, Japan.