Many intracellular pathogens subvert host membrane trafficking pathways to promote their replication.
multiplies in a membrane-bound parasitophorous vacuole (PV) that interacts with mammalian host ...organelles and intercepts Golgi Rab vesicles to acquire sphingolipids. The mechanisms of host vesicle internalization and processing within the PV remain undefined. We demonstrate that
sequesters a broad range of Rab vesicles into the PV. Correlative light and electron microscopy analysis of infected cells illustrates that intravacuolar Rab1A vesicles are surrounded by the PV membrane, suggesting a phagocytic-like process for vesicle engulfment. Rab11A vesicles concentrate to an intravacuolar network (IVN), but this is reduced in
and
parasites, suggesting that tubules stabilized by the TgGRA2 and TgGRA6 proteins secreted by the parasite within the PV contribute to host vesicle sequestration. Overexpression of a phospholipase TgLCAT, which is localized to the IVN, results in a decrease in the number of intravacuolar GFP-Rab11A vesicles, suggesting that TgLCAT controls lipolytic degradation of Rab vesicles for cargo release.
Secondary caries remains the main reason for dental restoration failure. Replacement of failed restorations accounts for 50%-70% of all restorations performed. Antibacterial adhesives could inhibit ...biofilm acids at tooth-restoration margins, and calcium phosphate (CaP) ions could remineralize tooth lesions. The objectives of this study were to: (1) incorporate nanoparticles of silver (NAg), quaternary ammonium dimethacrylate (QADM), and nanoparticles of amorphous calcium phosphate (NACP) into bonding agent; and (2) investigate their effects on dentin bonding and microcosm biofilms. An experimental primer was made with pyromellitic glycerol dimethacrylate (PMGDM) and 2-hydroxyethyl methacrylate (HEMA). An adhesive was made with bisphenol-A-glycerolate dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA). NAg was incorporated into primer at 0.1 wt %. The adhesive contained 0.1% NAg and 10% QADM, and 0%-40% NACP. Incorporating NAg into primer and NAg-QADM-NACP into adhesive did not adversely affect dentin bond strength (p > 0.1). Scanning electron microscopy showed numerous resin tags, and transmission electron microscopy revealed NAg and NACP in dentinal tubules. Viability of human saliva microcosm biofilms on primer/adhesive/composite disks was substantially reduced via NAg and QADM. Metabolic activity, lactic acid, and colony-forming units of biofilms were much lower on the new bonding agents than control (p < 0.05). In conclusion, novel dental bonding agents containing NAg, QADM, and NACP were developed with the potential to kill residual bacteria in the tooth cavity and inhibit the invading bacteria along tooth-restoration margins, with NACP to remineralize tooth lesions. The novel method of combining antibacterial agents (NAg and QADM) with remineralizing agent (NACP) may have wide applicability to other adhesives for caries inhibition.
The Nannochloropsis genus contains oleaginous microalgae that have served as model systems for developing renewable biodiesel. Recent genomic and transcriptomic studies on Nannochloropsis species ...have provided insights into the regulation of lipid production in response to nitrogen stress. Previous studies have focused on the responses of Nannochloropsis species to short-term nitrogen stress, but the effect of long-term nitrogen deprivation remains largely unknown. In this study, physiological and proteomic approaches were combined to understand the mechanisms by which Nannochloropsis oceanica IMET1 is able to endure long-term nitrate deprivation and its ability to recover homeostasis when nitrogen is amended. Changes of the proteome during chronic nitrogen starvation espoused the physiological changes observed, and there was a general trend toward recycling nitrogen and storage of lipids. This was evidenced by a global down-regulation of protein expression, a retained expression of proteins involved in glycolysis and the synthesis of fatty acids, as well as an up-regulation of enzymes used in nitrogen scavenging and protein turnover. Also, lipid accumulation and autophagy of plastids may play a key role in maintaining cell vitality. Following the addition of nitrogen, there were proteomic changes and metabolic changes observed within 24 h, which resulted in a return of the culture to steady state within 4 d. These results demonstrate the ability of N. oceanica IMET1 to recover from long periods of nitrate deprivation without apparent detriment to the culture and provide proteomic markers for genetic modification.
The Electron Microscopy Core Imaging Facility (EMCIF) of the University of Maryland Baltimore conducts 100-150 electron microscopy (EM) -related research projects and processes a wide range of ...specimens each year. Many experimental procedures are customized to meet the demands of each specific research project. In order to minimize the time required for record-keeping of a large number of samples and experimental details, we have developed a management database using Microsoft Office Access, a program included in the Microsoft Office Professional Suite. EMCIF day-to-day records are divided into several main data tables including client information, project information, sample description, project charges, project experiments, and lab reagents. Records are entered using a custom-designed entry form with drop-down menus to minimize typing. The whole database is safely stored in a web-based server and can be accessed by all EMCIF personnel from their own computers simultaneously. Using built-in command buttons, documents such as invoices, quotes, project summaries and experimental workflows can be printed as reports, exported to other programs, or e-mailed to clients with a single click. This Do-It-Yourself management system was initially constructed in 2009 with five tables designed to manage service records. It has been expanded and modified through the years to incorporate new experimental procedures, reagents, as well as other critical information. The database recently celebrated its ten years anniversary. It currently includes records for approximately 10,000 EM specimens, 1,500 projects and over 500 clients. The ease of navigation of the database allows the EMCIF director and its staff to track down information concerning any client, project, or sample with a few clicks. A significant advantage of this ‘DIY' database is its ease of adaptation and expansion to fit the changing needs of both the facility and its clients, an option often not available in commercial
Immune-checkpoint inhibitors (ICIs) changed the therapeutic landscape of patients with lung cancer. However, only a subset of them derived clinical benefit and evidenced the need to identify reliable ...predictive biomarkers. Liquid biopsy is the non-invasive and repeatable analysis of biological material in body fluids and a promising tool for cancer biomarkers discovery. In particular, there is growing evidence that extracellular vesicles (EVs) play an important role in tumor progression and in tumor-immune interactions. Thus, we evaluated whether extracellular vesicle PD-L1 expression could be used as a biomarker for prediction of durable treatment response and survival in patients with non-small cell lung cancer (NSCLC) undergoing treatment with ICIs.
Dynamic changes in EV PD-L1 were analyzed in plasma samples collected before and at 9 ± 1 weeks during treatment in a retrospective and a prospective independent cohorts of 33 and 39 patients, respectively.
As a result, an increase in EV PD-L1 was observed in non-responders in comparison to responders and was an independent biomarker for shorter progression-free survival and overall survival. To the contrary, tissue PD-L1 expression, the commonly used biomarker, was not predictive neither for durable response nor survival.
These findings indicate that EV PD-L1 dynamics could be used to stratify patients with advanced NSCLC who would experience durable benefit from ICIs.
Display omitted
Pancreatic cancer represents a life threatening disease with rising mortality. Although the synergistic combination of gemcitabine and albumin-bound paclitaxel has proven to enhance ...the median survival rates as compared to gemcitabine alone, their systemic and repeated co-administration has been associated with serious toxic side effects and poor patient compliance. For this purpose, we designed a thermosensitive and biodegradable hydrogel encapsulating targeted nanoparticles for the local and sustained delivery of gemcitabine (GEM) and paclitaxel (PTX) to pancreatic cancer. GEM and PTX were loaded into PR_b-functionalized liposomes targeting integrin α5β1, which was shown to be overexpressed in pancreatic cancer. PR_b is a fibronectin-mimetic peptide that binds to α5β1 with high affinity and specificity. The PR_b liposomes were encapsulated into a poly(δ-valerolactone-co-D,L-lactide)-b-poly(ethylene glycol)-b-poly(δ-valerolactone-co-D,L-lactide) (PVLA-PEG-PVLA) hydrogel and demonstrated sustained release of both drugs compared to PR_b-functionalized liposomes free in solution or free drugs in the hydrogel. Moreover, the hydrogel-nanoparticle system was proven to be very efficient towards killing monolayers of human pancreatic cancer cells (PANC-1), and showed a significant reduction in the growth pattern of PANC-1 tumor spheroids as compared to hydrogels encapsulating non-targeted liposomes with GEM/PTX or free drugs, after a one week treatment period. Our hybrid hydrogel-nanoparticle system is a promising platform for the local and sustained delivery of GEM/PTX to pancreatic cancer, with the goal of maximizing the therapeutic efficacy of this synergistic drug cocktail while potentially minimizing toxic side effects and eliminating the need for repeated co-administration.
Investigations conducted on feral African Sacred Ibises (Threskiornisaethiopicus) in western France led to the isolation of a strain with chlamydial genetic determinants. Ultrastructural analysis, ...comparative sequence analysis of the 16S rRNA gene, ompA, and of a concatenate of 31 highly conserved genes, as well as determination of the whole genome sequence confirmed the relatedness of the new isolate to members of the Chlamydiaceae, while, at the same time demonstrating a unique position outside the currently recognized species of this family. We propose to name this new chlamydial species Chlamydiaibidis .
The commercial marketplace has seen a rapid increase in the number of over-the-counter charcoal-containing mouthwashes. The purpose of this systemic review was to examine the clinical and laboratory ...evidence supporting therapeutic claims of efficacy and safety of use of charcoal-based mouthwashes. Secondly, the product labels and information of 36 commercially marketed charcoal mouthwashes were reviewed for active ingredients. Only 8% of charcoal mouthwashes contained an active ingredient, such as cetylpyridinium chloride or chlorhexidine. There is insufficient evidence to substantiate the therapeutic and cosmetic marketing claims of charcoal-based mouthwashes, including antimicrobial activity, anti-halitosis, tooth whitening, periodontal disease control, caries reduction and tooth remineralisation, among others. Moreover, there is no available information on charcoal particulate size or abrasivity of any of these products. Dental clinicians should advise their patients to exercise caution when using over-the-counter charcoal-containing mouthwashes because of the lack of evidence supporting therapeutic or cosmetic effectiveness as well as safety.
Although endosomal compartments have been suggested to play a role in unconventional protein secretion, there is scarce experimental evidence for such involvement. Here we report that recycling ...endosomes are essential for externalization of cytoplasmic secretory protein tissue transglutaminase (tTG). The de novo synthesized cytoplasmic tTG does not follow the classical ER/Golgi-dependent secretion pathway, but is targeted to perinuclear recycling endosomes, and is delivered inside these vesicles prior to externalization. On its route to the cell surface tTG interacts with internalized β1 integrins inside the recycling endosomes and is secreted as a complex with recycled β1 integrins. Inactivation of recycling endosomes, blocking endosome fusion with the plasma membrane, or downregulation of Rab11 GTPase that controls outbound trafficking of perinuclear recycling endosomes, all abrogate tTG secretion. The initial recruitment of cytoplasmic tTG to recycling endosomes and subsequent externalization depend on its binding to phosphoinositides on endosomal membranes. These findings begin to unravel the unconventional mechanism of tTG secretion which utilizes the long loop of endosomal recycling pathway and indicate involvement of endosomal trafficking in non-classical protein secretion.
PDF
