Apoptogenic effect of the lipophilic <i>o</i>-naphthoquinone CG 10-248 on rat hepatocytes: light and electron microscopy studies

CG 10-248 (3,4-dihydro-2,2-dimethyl-9-chloro-2H-naphtho[1,2b]pyran- 5,6-dione; CG-NQ), a β-lapachone analogue, modified the ultrastructure of rat hepatocytes, as demonstrated by light and electron microscopy. After 4 h incubation with 100 µM CG-NQ, the following effects were observed: (a) nuclear chromatin condensation; (b) chromatin fragmentation; (c) displacement of mitochondria, concentrated around the nucleus; (d) disruption or expansion of mitochondrial outer or inner membranes, respectively; (e) displacement and alteration of endoplasmic reticulum (rough and smooth); (f) decrease of microvilli; (g) blebbing of plasma membrane and production of apoptotic bodies formed by folding of plasma membrane fragments around mitochondria or peroxysomes; and (h) production of hydrogen peroxide. Expression of such effects varied according to hepatocyte samples and taken together strongly support an apoptotic action of CG-NQ dependent on “reactive oxygen species”.     

Structure of the stigma and style in sunflower (<i>Helianthus annuus</i> L.)

This is the first report of the ultrastructure of the stigma and style during and after anthesis in Helianthus annuus L. using light and transmission electron microscopy. The stigma is bifid with unicellular papillae. There is no secretion of lipids, carbohydrates or proteins at anthesis. The style is semisolid in the upper portion, closer to the stigma, and becomes solid below. Ultrastructural changes on cells of the stigma and the style are described. The transmitting tissue of the ovule is first evident 40 minutes after pollination and persists during the first stages of embryogenesis. Only one pollen tube per micropyle was observed growing through this tissue.     

Structure of the kidney of <i>Bufo arenarum</i>: Intermediate segment,distal tubule and collecting tubule

The ultrastructure of the intermediate segment (IS), distal tubule and collecting tubule (CT) of the south american toad Bufo arenarum, was studied by light and transmission electron microscopy. The IS is composed of cubical ciliated cells which propel the urine along the renal tubule. The distal tubule is divided into two portions: the early distal tubule (EDT) and the late distal tubule (LDT). The EDT is characterized by only one type of cells with well developed basolateral interdigitations and numerous elongated mitochondria, which are oriented normal to the basal surface. The “macula densa - like” is a specialized zone of the EDT in contact with the vascular pole, where cells are more tightly packed than in the rest of the tubule. The LDT shows two types of cells called dark and light cells according to the appearance of their cytoplasm. Dark cells have microplicae and few but long microvilli at their luminal surface, and abundant mitochondria in their cytoplasm. Light cells show basal and lateral infoldings and few mitochondria. The CT, which is composed of dark and light cells, exhibits an enlarged lumen with an undulated surface and dilated spaces between neighbouring cells.
This work is a contribution to the knowledge of the kidney of B. arenarum; frequently used as an experimental model for physiological and biochemical studies.     

Association between preterm birth risk and polymorphism and expression of the DNA repair genes <i>OGG1</i> and <i>APE1</i> in Saudi women

Genomic instability and mutations caused by increases in oxidative stress during pregnancy can damage the fetoplacental unit and can upshot preterm birth. Oxidative damage to DNA may possibly be involved in etiology of preterm birth (PTB) which can be repaired by DNA repair gene. In the present study, we assessed the association of base excision repair gene family by analyzing the association of single nucleotide polymorphisms and genes expression in 8-oxoguanine glycosylase-1 (OGG1) and apurinic-apyrimidinic endonuclease 1 (APE1) genes with risk of preterm birth in Saudi women. We analyzed genotypes of four single nucleotide polymorphisms (SNPs) (rs1052133, rs293795, rs2072668 and rs2075747) in OGG1 gene and three SNPs (rs1130409, rs3136814, and rs3136817) in APE1 gene using TaqMan Genotyping assay kits in 50 pairs of preterm cases and individually matched controls. Also, gene expression level was explored by RT-PCR in 10 pairs of preterm placental tissues and individually matched normal placental tissues. Two OGG1 SNP, rs1052133 (OR=0.497; c2=1.11; p=0.292) and rs2072668 (OR=0.408; c2=1.90; p=0.167) and one APE1 SNP rs3136817 (OR=0.458; c2=0.40; p=0.527) showed nonsignificant protective effect against PTB development. The expression of both genes under study was found lower in the PTB patients. Genotype and allele frequencies of both gene SNPs did not show any association with the risk of preterm delivery in Saudi women (P˃0.05). However, synthesis and release of OGG1 and APE1 proteins decreased in preterm placental tissues compared to term delivery reflects the probability of being one of the mechanisms leading to preterm birth.     

Ultrastructural characteristics of the lung of <i>Melanophryniscus stelzneri stelzneri</i> (Weyenberg, 1875) (Anura,Bufonidae)

The lung of the toad, Melanophryniscus stelzneri stelzneri was studied using scanning and transmission electron microscopy. In M.s.stelzneri the parenchyma forms a polygonal network arrangement, therefore the parenchyma is edicular. These spaces are delimited by the interconnection of third order septa which are covered by respiratory epithelium. Small patches of ciliated epithelium without goblet cells appear irregularly distributed on the septa. The respiratory epithelium consists of one type of pneumocyte, which shows characteristics of both type I and type II alveolar cells of higher vertebrates. The pneumocytes are irregular in shape and possess attenuated cytoplasmic processes, which spread around the capillaries to form the outer layer of the air-blood barrier. These cells contain different types of cytoplasmic bodies: electron dense bodies, multivesicular bodies and lamellar bodies. Dense bodies are probably the precursors of lamellar bodies and the multivesicular bodies are incorporated into the latter. Neuroepithelial bodies appear randomly distributed over the septa. These bodies are separated from the lumen of the lung by thin cytoplasmic processes of neighbouring pneumocytes. The air-blood barrier consists of three layers: epithelium, interstitial space and endothelium.
The relatively simple pulmonary structure of M.s.stelzneri is due to a lower degree of partitioning of the pulmonary lumen in comparison to the lung of other bufonid anurans, could be correlated with a well developed cutaneous and buccopharingeal respiration. The testing of this hypothesis awaits further studies.     

Cytogenetical and ultrastructural effects of copper on root meristem cells of <i>Allium sativum</i> L.

Different copper concentrations, as well as different exposure times, were applied to investigate both cytogenetical and ultrastructural alterations in garlic (Allium sativum L.) meristem cells. Results showed that the mitotic index decreased progressively when either copper concentration or exposure time increased. C-mitosis, anaphase bridges, chromosome stickiness and broken nuclei were observed in the copper treated root tip cells. Some particulates containing the argyrophilic NOR-associated proteins were distributed in the nucleus of the root-tip cells and the amount of this particulate material progressively increased with increasing exposure time. Finally, the nucleolar material was extruded from the nucleus into the cytoplasm. Also, increased dictyosome vesicles in number, formation of cytoplasmic vesicles containing electron dense granules, altered mitochondrial shape, disruption of nuclear membranes, condensation of chromatin material, disintegration of organelles were observed. The mechanisms of detoxification and tolerance of copper are briefly discussed.     

Inhibitory effect of jasmonic acid and ethylene on epicotyl growth and bud induction in the maritime pine, <i>Pinus pinaster</i> Soland. in Ait

Two independent parameters, epicotyl height (cm) and number of induced buds were studied on Pinus pinaster explants to analyse the effects of three phytohormones (6-benzylaminopurine, jasmonic acid, ethylene) which were combined or not in 11 different treatments. Epicotyle length diminished significantly in relation to the control medium (medium without exogen phytohormones) in presence of jasmonic acid, 6-benzylaminopurine or Ethephon (which is converted to ethylene in plants) in any of treatments. Concentrations of 100 μM of jasmonic acid and Ethephon had a greater inhibitory effect than the treatments with 10 μM. In addition to that, jasmonic acid was a stronger inhibitor than Ethephon in any of the tried combinations. There were no significant differences between the control treatment and the treatments with only 10 μM of jasmonic acid or Ethephon. However, 10 μM 6-benzylaminopurine induced bud formation. The different combinations of 6-benzylaminopurine with jasmonic acid and Ethephon showed that concentrations of 10 to 100 μM did not affect the number of induced buds. Jasmonic acid had an inhibitory effect which Ethephon only showed when combined with 100 μM of jasmonic acid and 10 μM of 6-benzylaminopurine. Three response groups were defined by cluster analysis: group 1 produced the greatest mean number of buds (4 to 5) and a mean epicotyl growth of 1 to 1.5 cm; group 2 produced 2 to 4 buds and a mean growth of 0.5 to 1.2 cm; group 3 produced only one bud and a mean epicotyl length of 1.2 to 2 cm.     

Examination of camptothecin and 10-hydroxycamptothecin in <i>Camptotheca acuminata</i> plant and cell culture,and the affected yields under several cell culture treatments

Camptothecin and its derivatives are monoterpenoid indole alkaloids exhibiting significant anti-tumor actions. With the aim of improving the production of these pharmaceuticals, the contents of camptothecin and 10-hydroxycamptothecin in different tissues including roots, stems, leaves, young flower buds, opening flowers, fading flowers and seeds from Camptotheca acuminata, were investigated. The young flower buds had the highest alkaloid concentrations (camptothecin, 2.46 mg/g of dry weight; 10- hydroxycamptothecin, 1.41 mg/g of dry weight). Callus showed lower concentrations but it should also be considered as a potential source of these pharmaceuticals. In the present study, the growth rate of Camptotheca acuminata cells in culture did not correlate with contents of camptothecin and 10-hydroxycamptothecin. Alkaloid accumulation by cells under various treatments (heavy metal ions, UV-B), methyl-jasmonate, abscisic acid, salicylic acid and hydrogen peroxide was examined, and the most notable effects appeared in the cells induced by UV-B light (which showed an 11-fold increase in camptothecin concentration) and by salicylic acid (which showed a 25-fold increase in 10-hydroxycamptothecin concentration). These results are significant in the context of the production of both pharmaceuticals.     

Proteome-wide screening for the analysis of protein targeting of <i>Chlamydia pneumoniae</i> in endoplasmic reticulum of host cells and their possible implication in lung cancer development

Available reports have confirmed a link between bacterial infection and the progression of different types of cancers, including colon, lungs, and prostate cancer. Here we report the Chlamydia pneumonia proteins targeting in endoplasmic reticulum (ER) using in-silico approaches and their possible role in lung cancer etiology. We predicted 48 proteins that target human ER, which may be associated with protein folding and protein-protein interactions during infection. The results showed C. pneumoniae proteins targeting human ER and their implications in lung cancer growth. These targeted proteins may be involved in competitive interactions between host and bacterial proteins, which may change the usual pathway functions and trigger the development of lung cancer. Moreover, C. pneumoniae unfolded protein accumulation in the human ER possibly induces ER stress, consequently activating the unfolded protein response (UPR), and providing a favorable microenvironment for cancer growth. The current study showed the C. pneumoniae protein targeting in ER of host cell and their implication in lung cancer growth. These results may help researchers better manage lung cancer and establish a molecular mechanism for C. pneumoniae lung cancer association.     

Effect of <i>Lycopus lucidus</i> Turcz. supplementation on gut microflora and short chain fatty acid composition in Crj: CD-1 mice

We investigated the diversity and composition of microflora in feces of Lycopus lucidus Turcz.-fed mice. Inaddition, we evaluated the production of major cytokines (Interleukin-6 and -10) which are related to inflammationand fatty acid composition of several tissues. 16S ribosomal DNA sequencing-based microbiome taxonomic profilinganalysis was performed utilizing the EzBioCloud data base. Male mice fed on L. lucidus showed a significantlyreduced number of lactic acid bacteria and coliform in the feces compared with the control group (p < 0.05). 16SrDNA sequencing analysis of fecal samples showed that L. lucidus supplementation decreased the community ofharmful microflora (Enterobacteriaceae including Escherichia coli and Bacteroides sp.) in feces compared with thecontrol group (p < 0.05). There were no significant differences in mRNA expression of cytokine IL-6 and IL-10between the control and L. lucidus fed groups. The fecal fatty acid composition in the L. lucidus group hadpercentages of 4:0, 6:0, 8:0 and 10:0 in the intestine but those short chain fatty acids were not detected in the controlgroup. Our results showed that L. lucidus supplementation influenced gut environment by decreasing harmfulmicroflora and increased the percentages of several short fatty acids.     

<i>In vitro</i> effects of 2-methoxyestradiol-bis-sulphamate on cell growth,morphology and cell cycle dynamics in the MCF-7 breast adenocarcinoma cell line

In the search for new and improved anticancer therapies, researchers have identified several potentially useful compounds. One of these agents is 2-methoxyestradiol-bis-sulphamate (2ME-BM), a sulphamoylated derivative of 2-methoxyestradiol. The objective of this study was to evaluate 2ME-BM’s in vitro efficacy as antiproliferative agent in the MCF-7 breast adenocarcinoma cell line. Light- and fluorescent microscopy showed decreased cell density, increased apoptotic characteristics and significant ultrastructural aberrations indicative of autophagic cell death after 24 hours of exposure at a concentration of 0.4μM. In addition, mitotic indices revealed that 2ME-BM induces a G₂M block. The latter was confirmed by flow cytometric analyses where increased sub-G₁ and G₂ /M fractions, as well as an increase in cyclin B1 levels were observed. Further in vitro research into the mechanism of this potentially useful anticancer compound is thus warranted.     

Application of two forms of silicon and their impact on the postharvest and the content of bioactive compounds in cucumber (<i>Cucumis sativus</i> L.) fruits

The metabolic activity of the fruits continues even after harvest, which results in the loss of bioactive compounds, a decrease in the quality of the fruits, softening and browning, among other negative effects. The use of certain elements such as silicon can improve postharvest quality, since it is involved in the metabolic, physiological and structural activity of plants, moreover can increase the quality of the fruits. In addition, nanotechnology has had a positive impact on crop yield, nutritional value, fruit quality and can improve antioxidant activity. For these reasons, the use of beneficial elements such as silicon in the form of nanoparticles can be a viable option to improve the characteristics of the fruits. In the present study was evaluated the application of potassium silicate (125, 250 and 500 mg L⁻¹) and SiO₂ nanoparticles (125, 250 and 500 mg L⁻¹) during the development of the crop. The results showed that the application of silicon (potassium silicate and silicon nanoparticles) increased the content of total soluble solids (up to 15.6% higher than control), titratable acidity (up to 38.8% higher than control), vitamin C (up to 78.2% higher than control), phenols (up to 22% higher than control), flavonoids (up to 64.6% higher than control), and antioxidant activity in lipophilic compounds (up to 56.2% higher than control). This study suggests that the use of silicon can be a good option to increase the content of bioactive compounds in cucumber fruits when they are applied during the development of the crop.     

Neural stem cell-conditioned medium upregulated the PCMT1 expression and inhibited the phosphorylation of MST1 in SH-SY5Y cells induced by Aβ_25-35

A progressive neurodegenerative disease, Alzheimer’s disease (AD). Studies suggest that highly expressedprotein isoaspartate methyltransferase 1 (PCMT1) in brain tissue. In the current study, we explored the effects ofneural stem cell-conditioned medium (NSC-CDM) on the PCMT1/MST1 pathway to alleviate Aβ_25-35-induceddamage in SH-SY5Y cells. Our data suggested that Aβ25-35 markedly inhibited cell viability. NSC-CDM or Neuralstem cell-complete medium (NSC-CPM) had a suppression effect on toxicity when treatment with Aβ_25-35, with agreater effect observed with NSC-CDM. Aβ_25-35 + NSC-CDM group exhibited an increase in PCMT1 expression.sh-PCMT1 markedly decreased cell proliferation and suppressed the protective role of NSC-CDM through theinduction of apoptosis and improved p-MST1 expression. Overexpression of PCMT1 reversed the Aβ_25-35-induceddecrease in cell proliferation and apoptosis. In summary, our findings suggest that NSC-CDM corrects the Aβ_25-35-induced damage to cells by improving PCMT1 expressions, which in turn reduces phosphorylation of MST1.     

Effect of Applied Load and Surface Roughness on the Tribological Properties of Ni-Based Superalloys Versus Ta<Subscript>2</Subscript>AlC/Ag or Cr<Subscript>2</Subscript>AlC/Ag Composites

The novel Ta₂AlC–20 vol.% Ag (TaAg) and Cr₂AlC–20 vol.% Ag (CrAg) composites were tribologically tested versus a Ni-based superalloy Inc718 (SA) by dry sliding at a sliding speed of 1 m/s at room temperature in air at loads from 3 N to 18 N. The TaAg composites were also tested at 8 and 18 N at 550 °C, and at a 3 N load against the SA with different surface roughnesses at 26 °C and 550 °C. At room temperatures, the coefficients of friction, μ’s, decreased from ~0.8–0.9 to ~0.3–0.4 for both the TaAg and CrAg composites as the applied normal force increased from 3 N to 8 N. Further increases in load to 18 N did not change the μ’s. The specific wear rates, sWR, increased with increased loads for the TaAg composite; they remained almost unchanged for the CrAg composite. This behavior was attributed to the formation of glaze tribofilms—similar to ones observed previously in these tribocouples at elevated temperatures and 3 N—promoted by the increased loads. Preconditioning of the SA surface by sliding against the TaAg composite at 550 °C and 8 N resulted in μ’s of <0.2 and sWR < 10⁻⁶ mm³/N-m in subsequent room temperature sliding at 3 N. Somewhat higher, but stable room temperature μ’s of ~0.3 and sWR of ~3 × 10⁻⁵ mm³/N-m were observed when the TaAg composites were slid versus a sandblasted SA surface at 500 °C and 3 N. It follows that in situ preconditioning of the tribo-surfaces is a powerful tool for improving the properties of the MAX/Ag-SA tribocouples. The relationship between sliding conditions, chemistries of tribofilms, and their properties are discussed.