Helicobacter pylori adhesion to gastric epithelial cells is mediated by glycan receptors

Helicobacter pylori adhesion to gastric epithelial cells constitutes a key step in the establishment of a successful infection of the gastric mucosa. The high representation of outer membrane proteins in the bacterial genome suggests the relevance of those proteins in the establishment of profitable interactions with the host gastric cells. Gastric epithelial cells are protected by a mucous layer gel, mainly consisting of the MUC5AC and MUC6 mucins. In addition to this protective role, mucins harbor glycan-rich domains that constitute preferential binding sites of many pathogens. In this article we review the main players in the process of H. pylori adhesion to gastric epithelial cells, which contribute decisively to the high prevalence and chronicity of H. pylori infection. The BabA adhesin recognizes both H-type 1 and Lewis b blood-group antigens expressed on normal gastric mucosa of secretor individuals, contributing to the initial steps of infection. Upon colonization, persistent infection induces an inflammatory response with concomitant expression of sialylated antigens. The SabA adhesin mediates H. pylori binding to inflamed gastric mucosa by recognizing sialyl-Lewis a and sialyl-Lewis x antigens. The expression of the BabA and SabA adhesins is tightly regulated, permitting the bacteria to rapidly adapt to the changes of glycosylation of the host gastric mucosa that occur during infection, as well as to escape from the inflammatory response. The growing knowledge of the interactions between the bacterial adhesins and the host receptors will contribute to the design of alternative strategies for eradication of the infection.

Silencing HIF-1α reduces the adhesion and secretion functions of acute leukemia hBMSCs

Hypoxia inducible factor-1α (HIF-1α) is an important transcription factor, which plays a critical role in the formation of solid tumor and its microenviroment. The objective of the present study was to evaluate the expression and function of HIF-1α in human leukemia bone marrow stromal cells (BMSCs) and to identify the downstream targets of HIF-1α. HIF-1α expression was detected at both the RNA and protein levels using real-time PCR and immunohistochemistry, respectively. Vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) were detected in stromal cells by enzyme-linked immunosorbent assay. HIF-1α was blocked by constructing the lentiviral RNAi vector system and infecting the BMSCs. The Jurkat cell/BMSC co-cultured system was constructed by putting the two cells into the same suitable cultured media and conditions. Cell adhesion and secretion functions of stromal cells were evaluated after transfection with the lentiviral RNAi vector of HIF-1α. Increased HIF-1α mRNA and protein was detected in the nucleus of the acute myeloblastic and acute lymphoblastic leukemia compared with normal BMSCs. The lentiviral RANi vector for HIF-1α was successfully constructed and was applied to block the expression of HIF-1α. When HIF-1α of BMSCs was blocked, the expression of VEGF and SDF-1 secreted by stromal cells were decreased. When HIF-1α was blocked, the co-cultured Jurkat cell’s adhesion and migration functions were also decreased. Taken together, these results suggest that HIF-1α acts as an important transcription factor and can significantly affect the secretion and adhesion functions of leukemia BMSCs.

Notch ligand Delta-like 1 promotes the metastasis of melanoma by enhancing tumor adhesion

Notch signaling plays a vital role in tumorigenicity and tumor progression by regulating proliferation, invasion, and the tumor microenvironment. Previous research by our group indicated that Notch ligand Delta-like 1 (Dll1) is involved in angiogenesis in melanoma, and we noticed that it took a longer time to trypsinize Dll1-expressing B16 melanoma cells than the control cells. In this article, we extended our study to investigate the effects of Dll1 on tumor cell adhesion and metastasis. Dll1 overexpression activated Notch signaling in B16 tumor cells and significantly enhanced the adhering capacity of B16 tumor cells both in vitro and in vivo. B16-Dll1 cells also had a higher metastatic potential than their counterpart in the mouse model of lung metastasis. Along with increased Dll1 expression, N-cadherin, but not E-cadherin, was upregulated in B16-Dll1 cells. These data suggested that Notch ligand Dll1 may enhance the adhesion and metastasis of melanoma cells by upregulation of N-cadherin.

Adhesion and production of degrading enzymes by bacteria isolated from biofilms in raw milk cooling tanks

Biofilms in milk cooling tanks compromise product quality even on farms. Due to the lack of studies of this topic, this study evaluated the microbiological conditions of raw milk cooling tanks on farms and characterized the microorganisms isolated from these tanks. Samples were wiped off with sterile swabs from seven milk cooling tanks in three different points in each tank. Mesophiles and psychrotrophic counts were performed in all samples. The isolation of Pseudomonas spp., Bacillus cereus and atypical colonies formed on selective media were also performed, totalizing 297 isolates. All isolates were tested for protease and lipase production and biofilm formation. Of the total isolates, 62.9% produced protease, 55.9% produced lipase, and 50.2% produced biofilm. The most widespread genus inside the milk cooling tank was Pseudomonas since it was not possible to associate this contamination with a single sampling point in the equipment. High counts of microorganisms were found in some cooling tanks, indicating poor cleaning of the equipment and providing strong evidences of microbial biofilm presence. Moreover, it is worth mentioning the milk potential contamination with both microbial cells and their degrading enzymes, which compromises milk quality.

Adhesion of uredospores of Phakopsora pachyrhizi on soybean seeds and their viability during storage

To study adhesion and viability of uredospores of the fungus Phakopsora pachyrhizi on soybean seeds during storage, suspension tests of those uredospores were carried out by washing seeds at each 30 days interval. Furthermore, germination and inoculation tests of uredospores on soybean plants were performed with uredospores collected from seeds of two soybean production areas, located in the municipalities "Chapada dos Guimarães" and "Tangará da Serra", State of Mato Grosso, Brazil. High levels of uredospores infestation were detected before storage [249.31 and 85.18 uredospores/100 seeds (U/100)] on seeds collected in both localities, respectively. After 30 days storage, these figures were 46.12 and 122.5 U/100; at 60 days were 14.62 and 26.62 U/100; and at 90 days were only 2.87 and 3,68 U/100, respectively; dropping to zero after 120 days storage. The percentage of germinated uredospores decreased with increasing storage periods and at 120 days germination percentage was nil. When uredospores were inoculated on soybean plants, rust symptoms were only observed for uredospores collected from freshly harvested seeds. Uredospores associated to soybean seed germinate until 90 days after storage, but are not viable after this time span. Infection of plants only occurs with inoculation of uredospores obtained from freshly harvested seeds.

Bacterial adhesion and biofilm formation on monolithic zirconia

Tutkimuksen tavoitteena oli selvittää bakteerien kiinnittymistä ja bakteeribiofilmin muodostumista implanttimateriaalien pinnalla. Monoliittisen zirkonian ja lasikeramien käyttö implanttikruunujen materiaaleina kasvaa jatkuvasti. Zirkoniaa käytetään myös abutmenttien materiaalina esteettisillä alueilla. Tällä hetkellä on vain vähän tutkimustietoa näiden implanttikruunumateriaalien sekä implanttikruunujen sementoimiseen käytetyn sementin pinnalla tapahtuvasta bakteeriadheesiosta ja biofilmin muodostumisesta. Bakteerien adheesiota ja biofilmin muodistumista tutkittiin neljän eri materiaalin pinnalla. Tutkimuksessa käytetyt materiaalit olivat: (1) Litiumdisilikaatti (LDS; IPS e.max CAD, Ivoclar Vivadent,kontrolli), (2) Kokonaan stabiloitu zirkonia (FSZ; Prettau Anterior, Zirkonzahn), (3) Osittain stabiloitu zirkonia (PSZ; Katana, Noritake), ja (4) Kaksoiskovetteinen sementti (DCC; Multilink hybrid abutment cement, Ivoclar Vivadent). Kaikki tutkimuksessa käytetyt materiaalit valmisteltiin ja kiillotettiin valmistajien ohjeiden mukaisesti Tutkittavat pinnat inkuboitiin Streptococcus mutans-suspensiossa +37°C:ssä asteessa. Bakteeriadheesiotestissä inkubointiaika oli 30 minuuttia ja biofilmitestissä vastaava aika oli 24 tuntia. Materiaalien pintoja tarkasteltiin myös elektronimikroskooppia käyttäen. Tutkimuksessa todettiin, että bakteeriadheesiossa oli eroja eri materiaalien välillä. Biofilmin. muodostumisessa ei todettu tilastollisesti merkittäviä eroja tutkittavien materiaalien välillä.

Estudio microscópico del diámetro apical de las raíces de caninos y molares inferiores con conductos mesiales separados.

Tesis (Especialidad en Endodoncia) UANL, 2010.

Análisis de biocompatibilidad de diferentes cementos de sellado apical.

Tesis (Maestría en Ciencias Odontológicas con Especialidad en Endodoncia) UANL, 2012.

Análisis de biocompatibilidad de tres cementos selladores endodónticos y tres materiales de sellado apical sólido a base de cemento portland.

Tesis (Maestría en Ciencias Odontológicas con Especialidad en Endodoncia) UANL, 2011.

Análisis de biocompatibilidad de tres cementos de sellado apical a base de silicato de calcio.

Tesis (Maestría en Ciencias Odontológicas con orientación en Endodoncia) UANL, 2014.

Adhesion and transcellular migration of neutrophils and B lymphocytes on fibroblasts

During tissue inflammation, infiltrated leukocytes may have physical contacts with fibroblasts. We observed that neutrophils and B lymphocytes adhered in a larger proportion than T cells on cultured fibroblasts. Microscopy showed that adhesion was also characterized by leukocyte engulfment by the fibroblasts. In migration assays, only neutrophils and B lymphocytes were selectively able to migrate through a fibroblast barrier. Adhesion and migration were increased by stimulation with tumor necrosis factor-alpha (TNF-alpha) and phorbol-12-myristate-13-acetate (PMA). Antibodies against ICAM-1/beta2 integrin blocked the interaction of neutrophils to fibroblasts. For B lymphocytes the couple VCAM-1/alpha4 integrin was also involved in this interaction. Human skin fibroblasts presented similar adhesion characteristics as rat cardiac fibroblasts. By measuring the distance between the border of migration holes and cadherin-positive adherens junctions, more than 65% of the holes correspond to the transcellular route over the paracellular route. Furthermore, vimentin staining revealed that the migration holes were highly nested by intermediate filaments in accordance with the transcellular route. Our results demonstrated that engulfment of neutrophils and B lymphocytes by fibroblasts resulted in selective passage by a transcellular route.

Microtubule disrupting N-phenyl-N’-(2-chloroethyl) ureas display anticancer activity on cell adhesion, P-glycoprotein and BCL-2-mediated drug resistance.

Objective: Our research program has focused on the development of promising, soft alkylating N-phenyl-N’-(2-chloroethyl)urea (CEU) compounds which acylate the glutamic acid-198 of β-tubulin, near the binding site of colchicum alkaloids. CEUs inhibit the motility of cancerous cells in vitro and, interestingly, exhibit antiangiogenic and anticancer activity in vivo. Mitotic arrest induced by microtubule-interfering agents such as CEUs remains the major mechanism of their anticancer activity, leading to apoptosis. However, we recently demonstrated that microtubule disruption by CEUs and other common antimicrotubule agents greatly alters the integrity and organization of microtubule-associated structures, the focal adhesion contact, thereby initiating anoikis, an apoptosis-like cell death mechanism caused by the loss of cell contact with the extracellular matrix. Methods: To ascertain the activated signaling pathway profile of CEUs, flow cytometry, Western blot, immunohistochemistry and transfection experiments were performed. Wound-healing and chick embryo assays were carried out to evaluate the antiangiogenic potency of CEUs. Results: CEU-induced apoptosis involved early cell cycle arrest in G2/M and increased level of CDK1/cycline B proteins. These signaling events were followed by the specific activation of the intrinsic apoptosis pathway, involving loss of mitochondrial membrane potential (Δψm) and ROS production, cytochrome c release from mitochondria, caspase activation, AIF nuclear translocation, PARP cleavage and nuclear fragmentation. CEUs maintained their efficacy on cells plated on pro-survival extracellular matrices or exhibiting overexpression of P-glycoprotein or the anti-apoptotic protein Bcl-2. Conclusion: Our results suggest that CEUs represent a promising new class of antimicrotubule, antiangiogenic and pro-anoikis agents.

Self adhesion of short Kevlar fibre -thermoplastic polyurethane composite

The self adhesion behaviour of thermoplastic polyurethane (TPU) in itself and its composite with short Kevlar fibre with respect to contact time, temperature, pressure, and fibre loading has been studied. The adhesion strength showed two linear increments of different slopes with respect to the square root of time: with temperature and pressure of contact, the adhesion strength was improved. The maximum strength was obtained with 20 phr of short fibre in only one of the mating substrates in the peel test sample. The duration for wetting and diffusion was shifted to longer time intervals with fibres loaded in both the substrates.

HUMAN PERICARDIAL FLUID AT MICROWAVE FREQUENCIES

This article reports a new method of analyzing pericardial fluid based on the measurement of the dielectric properties at microwave frequencies. The microwave measurements were performed by rectangular cavity perturbation method in the S-band of microwave frequency with the pericardial fluid from healthy persons as well as from patients suffering from pericardial effusion. It is observed that a remarkable change in the dielectric properties of patient samples with the normal healthy samples and these measurements were in good agreement with clinical analysis. This measurement technique and the method of extraction of pericardial fluid are simple. These results give light to an alternative in-vitro method of diagnosing onset pericardial effusion abnormalities using microwaves without surgical procedure.

Simptomatologia i microorganismes associats a la necrosi bruna apical de la noguera (Juglans regia)

La Necrosi Apical Bruna (BAN, brown apical necrosis, segons les sigles en anglès) Es va detectar per primer cop l’any 1997 a Extremadura degut a la severa caiguda de fruits. Avui dia la malaltia és present a quasi totes les zones productores de la mediterrània. Els símptomes difereixen dels provocats per Xanthomonas arboricola pv. juglandis i Gnomonia leptsostyla.. S’observa que els fruits afectats presenten una taca bruna a la zona apical i necrosi dels teixits interiors. El grup de Patologia Vegetal de la Universitat de Girona participa i dirigeix la tasca sobre l’etiologia de la BAN dins la xarxa europea d’investigació en bacteris patògens de fruiters ,COST873. Hi ha una certa controvèrsia en la definició dels símptomes i agents causals. Tots els grups coincideixen en afirmar que es tracta d’una malaltia complexa amb diferents organismes implicats