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Objectives Enterococcus faecalis has been associated with root canal infections, while Streptococcus mutans has a central role in the etiology of dental caries. One of the main reasons of endodontic failure has been associated to the presence of E. faecalis and the formation of biofilms. S. mutans inhabits the oral cavity, specifically the dental plaque, which is a multispecies biofilm formed on the hard surfaces of the tooth. The biofilm formation is the main factor determining the pathogenicity of numerous bacteria. Natural antimicrobial peptides in the saliva protect against pathogenic bacteria and biofilms. The aim of this study was to assess the ultrastructural damage induced by salivary peptides in bacteria involved in biofilms has not been previously studied. Material and methods Enterococcus faecalis and S. mutans incubated with cystatin C, chromogranin A, or histatin 5 were morphologically analyzed and counted. The ultrastructural damage was evaluated by transmission electron microscopy (TEM). Results A decrease in bacterial numbers was observed after incubation with cystatin C, chromogranin A, or histatin 5, compared to the control group (P < 0.001). Ultrastructural damage in E. faecalis and S. mutans incubated with salivary peptides was found in the cell wall, plasma membrane with a decreased distance between the bilayers, a granular pattern in the cytoplasm, and pyknotic nucleoids. Conclusions This study demonstrated that salivary peptides exert antibacterial activity and induce morphological damage on E. faecalis and S. mutans. Knowledge on the ultrastructural damage inflicted by salivary antimicrobial peptides on two important bacteria causing dental caries and root canal infections could aid the design of new therapeutic approaches to facilitate the elimination of these bacteria.

39 p.-5 fig., Biomonitoring is a valuable tool for assessing the presence and effects of air pollutants such as heavy metals (HM); due to their toxicity and stability, these compounds can affect human health and the balance of ecosystems. To assess its potential as a sentinel organism of HM pollution, the wild plant Gnaphalium lavandulifolium was exposed to four sites in the metropolitan area of México Valley (MAMV): Altzomoni (ALT) Coyoacán (COY), Ecatepec (ECA), and Tlalnepantla (TLA) during 2, 4, and 8 weeks, between October and November 2019. Control plants remained under controlled conditions. The chemical analysis determined twelve HM (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn) in the leaves. Macroscopic damage to the leaves, later determined in semi-thin sections under light microscopy, lead to a finer analysis. Transmission electron microscope (TEM) showed major structural changes: chromatin condensation, protoplast shrinkage, cytoplasm vacuolization, cell wall thinning, decreased number and size of starch grains, and plastoglobules in chloroplasts. All these characteristics of stress-induced programed cell death (sPCD) were related to the significant increase of toxic HM in the leaves of the exposed plants compared to the control (p < 0.05). Immunohistochemistry revealed a significant amount of proteases with caspase 3-like activity in ECA and TLA samples during long exposure times. Ultrastructural changes and sPCD features detected confirmed the usefulness of G. lavandulifolium as a good biomonitor of HM contamination. They supported the possibility of considering subcellular changes as markers of abiotic stress conditions in plants., This work was supported by the Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT-DGAPA) of the Universidad Nacional Autónoma de México through the project IN112517 and partially supported by Project grant PD12020-113018RB-100 (Spanish AEI and FEDER/EFRD).

Introducción: Se reconoce la importancia ecológica de los anfibios y reptiles, vitales en el funcionamiento de los ecosistemas y con patrones de reproducción diversos. No existen muchos estudios en biología de la reproducción en especies cubanas. El objetivo es mostrar el impacto de los estudios histológicos y ultraestructurales de las gónadas de anfibios y reptiles cubanos en la determinación del estado reproductivo del ejemplar y las etapas de la gametogénesis. Métodos: Se recolectaron once ranas del género Eleutherodactylus, un hílido y ocho sapos del género Peltophryne, además de tres especies de lagartijas; dos lagartos, un geckónido y cinco serpientes. Se procesaron las gónadas de ambos sexos con histología clásica, inmunofluorescencia, microscopía electrónica de transmisión y microscopía de fuerza atómica. Resultados: En anfibios y reptiles los ovocitos se clasifican en previtelogénicos, vitelogénicos y postvitelogénicos, acorde al proceso de síntesis y deposición del vitelo. Se aprecia una mayor cantidad de ovocitos vitelogénicos en etapa reproductiva. Los testículos contienen lóbulos seminíferos en anfibios donde tiene lugar la espermatogénesis cística y túbulos en reptiles, con espermatogénesis radial. Se identificó el órgano de Bidder en los sapos machos y en una hembra. La morfología de los espermatozoides en anfibios es similar incluso a nivel ultraestructural, y diferente entre los lagartos y las serpientes. Conclusiones: la histología clásica establece diferencias a nivel celular en ovarios y testículos, aspecto esencial para describir los ciclos gonadales que se suceden en anfibios y reptiles. Los caracteres histológicos y ultraestructurales permitieron describir los tipos celulares de la gametogénesis.

In the cell nucleus several ribonucleoproteins related to gene expression are present The nucleolus coiled bodies and other nuclear particles are among these structures Particles of nanometer size include perichromatin fibrils perichromatin and Balbiani ring granules interchromatin granules and Lacandonia granules All of them are involved in pre messenger RNA intranuclear metabolism Previous and recent research suggests that these particles are involved in transcription and processing of pre messenger RNA within the cell nucleus

The global, three-dimensional organization of RNA molecules in the nucleus is difficult to determine using existing methods. Here we introduce Proximity RNA-seq, which identifies colocalization preferences for pairs or groups of nascent and fully transcribed RNAs in the nucleus. Proximity RNA-seq is based on massive-throughput RNA barcoding of subnuclear particles in water-in-oil emulsion droplets, followed by cDNA sequencing. Our results show RNAs of varying tissue-specificity of expression, speed of RNA polymerase elongation and extent of alternative splicing positioned at varying distances from nucleoli. The simultaneous detection of multiple RNAs in proximity to each other distinguishes RNA-dense from sparse compartments. Application of Proximity RNA-seq will facilitate study of the spatial organization of transcripts in the nucleus, including non-coding RNAs, and its functional relevance.

Neutral electrolyzed water (NEW) was tested as a disinfectant against Listeria monocytogenes on the surface of table eggs. Eggs were collected from a single Bovans White flock and were exposed to L. monocytogenes. Artificially contaminated eggs were divided into three different treatment groups: NEW, 2% citric acid solution (CAS), and saline solution (SS). To evaluate the bactericidal effect, the Mexican norm for antimicrobial activity determination protocol was performed. The observed bactericidal effect was compared against those obtained from CAS and SS. Bacterial cells present on the eggshells were quantified. NEW exhibited a significantly higher bactericidal effect than CAS when evaluated on the surfaces of chicken eggshells (6.11 log10CFU/ml reduction in vitro and a 2.18 log10 CFU/egg reduction on eggs vs. 1.06 log10CFU/ml in vitro reduction and 1.74 log10CFU/egg). Additionally, CAS was found to react with the carbonate egg shield, resulting in a loss of cuticle integrity. Mineral content of NEW‐treated eggshells was similar to SS‐treated eggshells; however, CAS‐treated eggshells showed a significant decrease in phosphorous concentration compared to NEW treatment. In this study, we demonstrated the effect of NEW and CAS on the integrity of the L. monocytogenes wall using transmission electron microscopy. To the best of our knowledge, this is the first report of the effect of NEW against L. monocytogenes on eggshells. Our results show that NEW is a viable alternative solution for the disinfection of table eggs that does not affect the cuticle or shell.

During sporulation Bacillus subtilis Mfd couples transcription to nucleotide excision repair (NER) to eliminate DNA distorting lesions. Here, we report a significant decline in sporulation following Mfd disruption, which was manifested in the absence of external DNA-damage suggesting that spontaneous lesions activate the function of Mfd for an efficient sporogenesis. Accordingly, a dramatic decline in sporulation efficiency took place in a B. subtilis strain lacking Mfd and the repair/prevention guanine oxidized (GO) system (hereafter, the ∆GO system), composed by YtkD, MutM and MutY. Furthermore, the simultaneous absence of Mfd and the GO system, (i) sensitized sporulating cells to H2O2, and (ii) elicited spontaneous and oxygen radical-induced rifampin-resistance (Rifr) mutagenesis. Epifluorescence (EF), confocal and transmission electron (TEM) microscopy analyses, showed a decreased ability of ∆GO ∆mfd strain to sporulate and to develop the typical morphologies of sporulating cells. Remarkably, disruption of sda, sirA and disA partially, restored the sporulation efficiency of the strain deficient for Mfd and the ∆GO system; complete restoration occurred in the RecA− background. Overall, our results unveil a novel Mfd mechanism of transcription-coupled-repair (TCR) elicited by 8-OxoG which converges in the activation of a RecA-dependent checkpoint event that control the onset of sporulation in B. subtilis.

Mexico City has been classified as one megacity, its altitude, thermal inversions, and high seasonal radiation are factors that prevent dispersion of pollutants, which effects are detrimental to health. Therefore, it is important to have an organism that allows evaluate the damage caused by such exposure, as is the case of mosses that obtain nutrients from the atmosphere; this property makes them excellent biomonitors to evaluate genotoxic damage caused by exposure to pollutants, in addition to its large accumulation capacity. For these reasons and to relate the effects of atmospheric pollution with a biological response, we propose to use the moss Hypnum amabile as a bioaccumulator of atmospheric pollutants and biomonitor of the genotoxic effect that the air pollution can induce it through the comet assay. Mosses were placed in five localities of Mexico City and the metropolitan area on the first days of each month of the dry (cold and warm) and rainy seasons, with a 30-day exposure, after which they were changed for a new sample (for 8 months). Each month, the moss exposed was collected and nuclei were isolated to perform comet assay. To demonstrate heavy metal bioaccumulation capacity, samples were observed in a transmission electron microscope and qualitative microanalysis by scanning electron microscopy was carried out parallel. The chemical analysis detected 14 heavy metals by mass spectrometry method with inductively coupled plasma source. Additionally, 22 polycyclic aromatic hydrocarbons were also determined by gas chromatography-mass spectrometry. Analysis of variance and Kruskal-Wallis test were performed to compare DNA damage of each station against control, which was maintained in the laboratory in a chamber with filtered air. This is the first study on the genotoxicity of mosses exposed to the atmosphere of Mexico City and metropolitan area that in addition to proving their accumulation capacity shows their ability to respond to atmospheric pollutants.

Background and aimsThis is the first time that obesity and diabetes mellitus (DM) as protein conformational diseases (PCD) are reported in children and they are typically diagnosed too late, when β-cell damage is evident. Here we wanted to investigate the level of naturally-ocurring or real (not synthetic) oligomeric aggregates of the human islet amyloid polypeptide (hIAPP) that we called RIAO in sera of pediatric patients with obesity and diabetes. We aimed to reduce the gap between basic biomedical research, clinical practice-health decision making and to explore whether RIAO work as a potential biomarker of early β-cell damage.Materials and methodsWe performed a multicentric collaborative, cross-sectional, analytical, ambispective and blinded study; the RIAO from pretreated samples (PTS) of sera of 146 pediatric patients with obesity or DM and 16 healthy children, were isolated, measured by sound indirect ELISA with novel anti-hIAPP cytotoxic oligomers polyclonal antibody (MEX1). We carried out morphological and functional studied and cluster-clinical data driven analysis.ResultsWe demonstrated by western blot, Transmission Electron Microscopy and cell viability experiments that RIAO circulate in the blood and can be measured by ELISA; are elevated in serum of childhood obesity and diabetes; are neurotoxics and works as biomarkers of early β-cell failure. We explored the range of evidence-based medicine clusters that included the RIAO level, which allowed us to classify and stratify the obesity patients with high cardiometabolic risk.ConclusionsRIAO level increases as the number of complications rises; RIAOs > 3.35 μg/ml is a predictor of changes in the current indicators of β-cell damage. We proposed a novel physio-pathological pathway and shows that PCD affect not only elderly patients but also children. Here we reduced the gap between basic biomedical research, clinical practice and health decision making.

To date, no safe vaccine or antivirals for Zika virus (ZIKV) infection have been found. The pathogenesis of severe Zika, where host and viral factors participate, remains unclear. For the control of Zika, it is important to understand how ZIKV interacts with different host cells. Knowledge of the targeted cellular pathways which allow ZIKV to productively replicate and/or establish prolonged viral persistence contributes to novel vaccines and therapies. Monocytes and endothelial vascular cells are the main ZIKV targets. During the infection process, cells are capable of releasing extracellular vesicles (EVs). EVs are mediators of intercellular communication. We found that mosquito EVs released from ZIKV-infected (C6/36) cells carry viral RNA and ZIKV-E protein and are able to infect and activate na&iuml, ve mosquito and mammalian cells. ZIKV C6/36 EVs promote the differentiation of na&iuml, ve monocytes and induce a pro-inflammatory state with tumor necrosis factor-alpha (TNF-&alpha, ) mRNA expression. ZIKV C6/36 EVs participate in endothelial vascular cell damage by inducing coagulation (TF) and inflammation (PAR-1) receptors at the endothelial surface of the cell membranes and promote a pro-inflammatory state with increased endothelial permeability. These data suggest that ZIKV C6/36 EVs may contribute to the pathogenesis of ZIKV infection in human hosts.

Background: Lacandonia granules are extranucleolar ribonucleoprotein (RNPs) particles, 32 nanometers in diameter that were first described in the nucleus of Lacandonia schismatica . Cytochemical and immunocytochemical studies suggest that these particles are equivalent to perichromatin and Balbiani ring granules described in mammals and salivary glands cells of the insect Chironomus tentans, respectively. Lacandonia granules are also present in the related Triuris brevystilis , and they were later described in the gymnosperm Ginkgo biloba . These findings suggest that Lacandonia granules have a wider distribution in the plant kingdom. Species study: The plant Welwitschia mirabilis, a gymnosperm of the order Gnetales. Hyphotesis: Lacandonia granules are present in the cell nucleus of W. mirabilis . Methods: Plants were cultivated in a germination chamber and samples of leaves were processed for transmission electron microscopy. Thin sections were stained with the EDTA technique preferential for ribonucleoproteins and osmium amine specific for DNA and observed with a microscopy. Results: Light, electronic and atomic force microscopy revealed that cell nuclei of W. mirabilis display a reticulated arrangement of chromatin. Moreover, granules of 32.17 ± 1.7 nm in diameter were observed among strands of reticulated chromatin. Conclusions: Our results indicate that Lacandonia granules are present in the nuclei of the gnetal W. mirabilis.

Light and electron microscopy have been used to study cell structure for many years, but atomic force microscopy is a more recent technique used to analyze cells, mainly due to the absence of techniques to prepare the samples. Isolated molecules or organelles, whole cells, and to a lesser extent in situ cell structure have been observed by different atomic force microscopy imaging modes. Here, we review efforts intended to analyze in situ the cell structures using approaches involving imaging of the surface of semithin sections of samples embedded in resin and sections prepared with an ultramicrotome. The results of such studies are discussed in relation to their implications to analyze the fine structure of organelles at the nanoscale in situ at enhanced resolution compared to light microscopy.

The formation of amyloid oligomers and fibrils of the human islet amyloid polypeptide (hIAPP) has been linked with β- cell failure and death which causes the onset, progression, and comorbidities of diabetes. We begin to unpack the aggregation-oligomerization-fibrillization process of these oligomers taken from sera of pediatric patients. The naturally occurring or real hIAPP (not synthetic) amyloid oligomers (RIAO) were successfully isolated, we demonstrated the presence of homo (dodecamers, hexamers, and trimers) and hetero-RIAO, as well as several biophysical characterizations which allow us to learn from the real phenomenon taking place. We found that the aggregation/oligomerization process is active in the sera and showed that it happens very fast. The RIAO can form fibers and react with anti-hIAPP and anti-amyloid oligomers antibodies. Our results opens the epistemic horizon and reveal real differences between the four groups (Controls vs obesity, T1DM or T2DM) accelerating the process of understanding and discovering novel and more efficient prevention, diagnostic, transmission and therapeutic pathways.

Neutral Electrolyzed Water (NEW) was tested in vitro and on artificially contaminated eggs against Salmonella enterica subsp. enterica or Escherichia coli. The antibacterial effect was measured 30 s after treatment. NEW microbicide activity results were compared against 2% citric acid and 0.9% saline solutions. NEW caused an in vitro decrease in Salmonella titers by ˃5.56 Log10 CFU mL−1 and in artificially contaminated eggs by ˃1.45 Log10 CFU/egg. When it was tested against E. coli, it decreased in vitro bacterial titers by ˃3.28 Log10 CFU mL−1 and on artificially contaminated eggs by ˃6.39 Log10 CFU/egg. The 2% citric acid solution caused an in vitro decrease of 0.4 Log10 CFU mL−1 of Salmonella and E. coli and on eggs artificially contaminated with E. coli or Salmonella there was a decrease of 0.06 and 0.62 Log10 CFU/egg respectively. We evaluated egg cuticle integrity by scanning electron microscopy after treatments with evaluated solutions; the 2% citric acid solution caused damage to the cuticle and exposed eggshell pores and no interaction of NEW or NaCl with the cuticle was observed. NEW treatment showed a fast-bactericidal effect in vitro and table eggs.

Trypanosoma cruzi, which causes Chagas disease, is a significant health threat in many countries and affects millions of people. Given the magnitude of this disease, a broader understanding of trypanocidal mechanisms is needed to prevent and treat infection. Natural endoperoxides, such as ergosterol peroxide, have been shown to be toxic to parasites without causing harm to human cells or tissues. Although prior studies have demonstrated the trypanocidal activity of ergosterol peroxide, the cellular and molecular mechanisms remain unknown. The results of this study indicate that a free-radical reaction occurs in T. cruzi following ergosterol peroxide exposure, leading to cell death. Using a combination of biochemical, microscopic and in silico experimental approaches, we have identified, for the first time, the cellular and molecular cytotoxic mechanism of an ergosterol peroxide obtained from Pleurotus ostreatus (Jacq) P. Kumm. f. sp. Florida.

Many reports investigating the hippocampus have demonstrated an increase in neuronal damage, cellular loss, oxidative stress and mitochondrial DNA damage during status epilepticus (SE); however, information regarding alterations in mitochondrial fission and fusion events in SE is lacking. The aim of the present study was to examine the possible imbalance between mitochondrial fission and fusion in the hippocampus of male rats after acute seizure mediated by SE. In this study, we used ninety animals were randomly divided into control and SE groups and subjected to the lithium-pilocarpine model of epilepsy. Hippocampi were obtained at 3, 24 and 72h after SE, and the cytoplasmic and mitochondrial fractions of the cells were used to analyze changes in the Drp1 and Fis1 fission proteins and the Mfn1 and Opa1 fusion proteins by western blot analysis. Moreover, changes in the expression of fission and fusion mRNA transcripts were evaluated by real-time PCR. Mitochondrial morphology was also analyzed using standard transmission electron microscopy. Our data showed that the fission-related mRNA Drp1 was down-regulated rapidly after SE, while Fis1 did not show any significant changes in expression. Moreover, the mitochondrial fusion-associated proteins Mfn1 and Opa1 exhibited an increase in expression at 72h after SE. Electron microphotography revealed several morphological changes, such as swollen mitochondria and damage of the inner mitochondrial membrane, at 24h; at 72h elongation of some mitochondrial was also observed. Our results suggest that after the initiation of SE, the main regulator of the fission mRNA Drp1 is down-regulated, which in turn regulates mitochondrial fission and leads to an increase in the Mfn1 and Opa1 proteins to induce mitochondrial fusion, suggesting an imbalance of the fission and fusion processes.

Desmodium diversity has been mainly classified using fruit characters, and because of variability in these and other characters, the taxonomy has sometimes been problematic and thus, there is a need for clarification and taxonomic reassessments. This is the case for the Desmodium procumbens group, where several infraspecific taxa have been named. The phylogenetic relationships among taxa referred to this group is unknown, and the taxonomic status has been recently revised only for some of the taxa. In this study, pollen morphology and ultrastructure of D. neomexicanum, D. procumbens var. procumbens, D. procumbens var. exiguum, D. procumbens var. longipes and D. procumbens var. transversum, belonging to the Mexican Desmodium procumbens group, were examined using light, phase-contrast, scanning electron and transmission electron microscopy, in order to establish palynological characters that might contribute to a better taxonomic resolution. Pollen grains are tricolporate, radiosymmetric, oblate sph...

Nucleolar assembly is a cellular event that requires the synthesis and processing of ribosomal RNA, in addition to the participation of pre-nucleolar bodies (PNBs) at the end of mitosis. In mammals and plants, nucleolar biogenesis has been described in detail, but in unicellular eukaryotes it is a poorly understood process. In this study, we used light and electron microscopy cytochemical techniques to investigate the distribution of nucleolar components in the pathway of nucleolus rebuilding during closed cell division in epimastigotes ofTrypanosoma cruzi, the etiologic agent of American trypanosomiasis. Silver impregnation specific for nucleolar organizer regions and an ethylenediaminetetraacetic acid regressive procedure to preferentially stain ribonucleoprotein revealed the conservation and dispersion of nucleolar material throughout the nucleoplasm during cell division. Furthermore, at the end of mitosis, the argyrophilic proteins were concentrated in the nucleolar organizer region. Unexpectedly, accumulation of nucleolar material in the form of PNBs was not visualized. We suggest that formation of the nucleolus in epimastigotes ofT. cruzioccurs by a process that does not require the concentration of nucleolar material within intermediate nuclear bodies such as mammalian and plant PNBs.

The nucleolus is a nuclear organelle involved in ribosome biogenesis. In most eukaryotes this structure disperses during prophase through anaphase and reorganizes at telophase by a process known as nucleologenesis. This process involves new transcription of ribosomal DNA at the nucleolar organizer region and the formation of prenucleolar bodies fusing to it. In Giardia lamblia, for a long time considered the only anucleolated eukaryote, a very small nucleolus has been recently described. In order to evaluate whether nucleologenesis is also present in Giardia, we analyzed the distribution of nucleolar material during telophase using different light and electron microscopy techniques including silver staining for the nucleolar organizer. Results indicate that in G. lamblia, nucleolar elements persist mainly as an intranuclear peripheral organelle during all stages of division, including telophase, however, no prenucleolar bodies are detected in the nucleoplasm. Therefore, in the parasite, nucleolar material is present throughout cell division including telophase and formation of prenucleolar bodies may not be required for nucleologenesis.

This work explores the influence of controlled acidification on lipid accumulation in S. obtusiusculus AT-UAM under N-deplete conditions. The protocol included determination of the acidification procedure (CO2 or HCl) and the application chronology in flat panel photobioreactors, operated under controlled conditions. The highest lipid content and productivity of 60% glipids gDCW−1 and 85 mg L−1 d−1, respectively, were obtained when controlled acidification to pH of 5.5 was applied after 80 h of operation under N-depletion. The strategy was also applied successfully in a larger scale using different configurations such as bubble-column photobioreactors and raceway ponds, operated outdoors, yielding a maximum lipid content of 45% glipids gDCW−1 in both systems. Globally, the lipid content increased almost twice the value obtained without acidification in indoor and outdoor conditions. The analysis revealed that no major changes in fatty acid profile occurred, suggesting a high specificity of the microalga toward lipid production; however, significant changes in the ultrastructure of the subcellular components and the cell wall were observed.

Human islet amyloid peptide (hIAPP1–37) aggregation is an early step in Diabetes Mellitus. We aimed to evaluate a family of pharmaco-chaperones to act as modulators that provide dynamic interventions and the multi-target capacity (native state, cytotoxic oligomers, protofilaments and fibrils of hIAPP1–37) required to meet the treatment challenges of diabetes. We used a cross-functional approach that combines in silico and in vitro biochemical and biophysical methods to study the hIAPP1–37 aggregation-oligomerization process as to reveal novel potential anti-diabetic drugs. The family of pharmaco-chaperones are modulators of the oligomerization and fibre formation of hIAPP1–37. When they interact with the amino acid in the amyloid-like steric zipper zone, they inhibit and/or delay the aggregation-oligomerization pathway by binding and stabilizing several amyloid structures of hIAPP1–37. Moreover, they can protect cerebellar granule cells (CGC) from the cytotoxicity produced by the hIAPP1–37 oligomers. The modulation of proteostasis by the family of pharmaco-chaperones A–F is a promising potential approach to limit the onset and progression of diabetes and its comorbidities.

Two untapered, heterocytous species were observed and collected from the intertidal and supratidal zones of the Mexican coastline of the Pacific Ocean near Oaxaca and from the Gulf of Mexico. These populations were highly similar in morphology to the freshwater taxon Petalonema incrustans in the Scytonemataceae. However, 16S rRNA sequence data and phylogenetic analysis indicated that they were sister taxa to the epiphyllic, Brazilian species Phyllonema aveceniicola in the Rivulariaceae, described from culture material. While genetic identity between the two new species was high, they differed significantly in morphology, 16S rRNA gene sequence identity, and sequence and structure of the 16S-23S ITS region. Their morphology differed markedly from the generitype of the previously monotypic Phyllonema, which has tapered, heteropolar, single-false branched trichomes with very thin or absent sheath. The two new species, Phyllonema ansata and Phyllonema tangolundensis, described from both culture and environmental material, have untapered, isopolar, geminately false branched trichomes with thick, lamellated sheaths, differences so significant that the species would not be placed in Phyllonema without molecular corroboration. The morphological differences are so significant that a formal emendation of the genus is required. These taxa provide a challenge to algal taxonomy because the morphological differences are such that one would logically conclude that they represent different genera, but the phylogenetic evidence for including them all in the same genus is conclusive. This conclusion is counter to the current trend in algal taxonomy in which taxa with minor morphological differences have been repeatedly placed in separate genera based primarily upon DNA sequence evidence.

A gall is the result of complex interactions between a gall inducing-insect and its host plant. Certain groups of insects have the ability to induce a new structure, a gall, on plant organs by altering the normal growth of the host involved plant organ. The gall usually provides shelter and nutrients, in addition to protection against adverse environmental conditions and natural enemies to the inducing insect and its offspring. The ecological uniqueness of a gall is that it allows the inducing-insect to complete their life cycles. In this study, we have described the structures of different stages of growth of a gall induced by Amphibolips michoacaensis on the buds of leaves on Quercus castanea (Fagaceae) to know the subcellular changes during development. The gall consist of various layers such as a nutritive tissue, a lignified sheath, a spongy layer and an outermost epidermis around a centrally located larval chamber. The nutritive cell of the larval chamber show nuclear and nucleolar hypertrophy in the early phases of growth. The granular profile of the nucleolus suggests an active synthesis of ribosomes indicating an accelerated protein synthesis in these cells. During early stages of growth, the cells of the spongy layers within galls are nucleate and nucleolate and include amyloplasts, and the cytoplasm is less abundant. During later growth stages, the spongy cells are enucleate and enucleolate. Chloroplasts occur in the epidermal cells during early stages of growth, indicating that galls are photosynthetically active in early stages of growth. During intermediate stages of growth, a gradual loss of cellular components occurs commencing in the epidermal cells and progressing towards the nutritive cells.

Endosymbiosis is a common phenomenon in nature, especially between bacteria and insects, whose typically unbalanced diets are usually complemented by their obligate endosymbionts. While much interest and focus has been directed toward phloem-feeders like aphids and mealybugs, blood-feeders such as the Lone star tick (Amblyomma americanum), Glossina flies, and the human body louse (Pediculus humanus corporis) depend on obligate endosymbionts which complement their B-vitamin-deficient diets, and thus are required for growth and survival. Glossiphoniid leeches have also been found to harbor distinct endosymbionts housed in specialized organs. Here, we present the genome of the bacterial endosymbiont from Haementeria officinalis, first of a glossiphoniid leech. This as-yet-unnamed endosymbiont belongs to the Gammaproteobacteria, has a pleomorphic shape and is restricted to bacteriocytes. For this bacterial endosymbiont, we propose the name Candidatus Providencia siddallii. This symbiont possesses a highly reduced genome with high A+T content and a reduced set of metabolic capabilities, all of which are common characteristics of ancient obligate endosymbionts of arthropods. Its genome has retained many pathways related to the biosynthesis of B-vitamins, pointing toward a role in supplementing the blood-restricted diet of its host. Through comparative genomics against the endosymbionts of A. americanum, Glossina flies, and P. humanus corporis, we were able to detect a high degree of metabolic convergence among these four very distantly related endosymbiotic bacteria.

En este trabajo se caracterizan y comparan las punteaduras, la pared secundaria y la membrana de la punteadura en elementos traqueales en dos especies de Cactaceae con madera contrastante. Se recolectaron individuos adultos de Echinocactus grusonii (madera dimorfa) y Mammillaria compressa (madera no fibrosa) pertenecientes a la tribu Cacteae y se procesaron utilizando diferentes métodos para su observación por microscopía fotónica, electrónica de barrido y de transmisión. Los elementos de vaso tienen placas de perforación simples con un reborde, así como diferentes grados de acumulación de la pared secundaria desde anulares y helicoidales hasta punteaduras pseudoescalariformes y alternas. En M. compressa la pared secundaria en algunos elementos de vaso puede acumularse tanto en forma anular como helicoidal. En E. grusonii , la membrana de las punteaduras alternas en los elementos de vaso tiene poros muy pequeños, apreciables con aumentos altos exclusivamente con microscopia electrónica. En las fibras se observaron organelos núcleo y mitocondrias y un material electrodenso; además el par de punteaduras fibra-fibra tiene un pequeño reborde visto con microscopia electrónica de transmisión no descrito para la familia. Las diferencias en la membrana de la punteadura entre ambas especies posiblemente están relacionadas con su capacidad de evitar embolismos lo que se podrá demostrar con trabajo empírico.

Background The current drugs for Chagas Disease caused by the protozoan Trypanosoma cruzi have limited therapeutic potential and are associated with serious side effects. Natural products can aid to develop new chemotherapeutic agents. Several natural coumarins, especially Mammea A/BA, have shown significant activity against T. cruzi and low toxicity on human lymphocytes, but its effectivity on a wide range of strains need to be tested, as well as to deepen in their mode of action and safety. Hypothesis/Purpose To discern the effects and explore the action mechanisms of mammea A/BA and a mixture of mammea coumarins isolated from Calophyllum brasiliense on Mexican strains of T. cruzi belonging to different genotypes and compare its effectivity with the drug benznidazole. Study design We evaluated the trypanocidal activity in vitro of mammea A/BA (93.6%), and a mixture of coumarins, mammea A/BA + A/BB + A/BD (86:10:1%) on Mexican T. cruzi strains belonging to different genotypes Ninoa, Queretaro (TcI) and Ver6 (TcVI). Material and methods Mammea A/BA and the mixture of coumarins, were isolated from Calophyllum brasiliense, identified by proton NMR and purity determined by HPLC. The in vitro trypanocidal activity was evaluated on mobility, growth recovery, morphology and infectivity of T. cruzi. The cytotoxicity on mammalian cells was compared with benznidazole. The ultrastructure of the treated epimastigotes was analyzed by transmission electron microscopy (TEM). Results Mammea A/BA and the mixture of coumarins showed high trypanocidal activity, affecting the mobility, growth recovery, morphology, ultrastructure of epimastigotes, and drastically reduce trypomastigotes infectivity on Vero cells. These substances were four times more potent than benznidazole and showed low cytotoxicity and high selectivity index. The TEM showed severe alterations on the plasmatic membrane, nuclear envelope, as well as, mitochondrial swelling, that leads to the death of parasites. Conclusion Mammea A/BA (93.6%) and a mixture of mammea A/BA + A/BB and A/BD (86: 10: 1%) isolated from the tropical tree C. brasiliense showed higher trypanocidal activity than the current drug benznidazole on three Mexican strains of T. cruzi. These compounds induced severe physiological and morphological alterations. These results suggest their possible use in preclinical studies.