(C,D) Ormeloxifene also showed a marked decrease in tumor pounds and quantity than in comparison to PBS. cell routine at G1-S changeover, inducing apoptosis, reducing PI3K and Akt phosphorylation, mitochondrial membrane potential, and modulating G1-S changeover related protein (p21, cyclin E and Cdk2). Furthermore, ORM repressed the manifestation of HPV E6/ E7 oncoproteins and restored the manifestation of their downstream focus on tumor suppressor protein (p53, Rb and PTPN 13). As a total result, ormeloxifene induces radio-sensitization in cervical tumor cells and triggered potent tumor development inhibition in orthotopic mouse model. Used collectively, ormeloxifene represents an alternative solution restorative modality for cervical tumor which may possess rapid medical translation since it is already tested safe for human being use. and displays superb anti-tumor activity in orthotopic mice style of cervical tumor. Results out of this scholarly research, collectively, claim that ormeloxifene offers great potential to become novel restorative agent for the administration of cervical tumor. Outcomes Ormeloxifene treatment inhibits mobile development and motility of varied cervical PR-104 tumor cells To look for the aftereffect of ormeloxifene on cell development of varied cervical tumor cells, we performed cell proliferation (MTS) assays with Caski and SiHa (HPV positive) (Fig.?1A) and, C33A and HT3 (HPV bad) (Fig.?S1A). Cells had been treated with ormeloxifene at micro-molar runs for 48?hours. All cell lines demonstrated a significant reduction in a dose-dependent way and a extreme inhibitory impact was discovered between 20?M and 25?M dosages. A rise kinetic test was also performed using xCELLigence RTCA program (Fig.?1B) to verify ormeloxifenes influence on cellular development of Caski and SiHa cell lines regarding time. Colony developing capability is an important real estate of cancerous cells. Therefore, we evaluated colony developing assays to look LEP for the long-term aftereffect of ormeloxifene on cervical tumor cell lines. Ormeloxifene demonstrated PR-104 a significant influence on clonogenic potential of most tested cervical tumor cell lines (Figs.?1C,D,S1B,C) inside a dose-dependent way. We also examined the metastatic properties of cervical tumor cells after ormeloxifene treatment with cell migration and invasion assays using Boyden chamber migration and Boyden chamber matrigel invasion assays. Both Caski and SiHa cells demonstrated an inhibition of migration and invasion (Fig.?1E) with a rise in ormeloxifene focus. A real period kinetic evaluation for migration and invasion was also performed using xCELLigence RTCA program (Fig.?1F) to verify ormeloxifenes influence on metastasis of Caski and SiHa cells, and outcomes were in keeping with the Boyden chamber assays. Furthermore, the migratory capability of cells was examined through the use of an agarose bead assay (Fig.?S1D). Ormeloxifene treatment once again demonstrated an inhibition of migration in dosage and time reliant way in both cell lines. Open up in another windowpane Shape 1 Ormeloxifene inhibits cell motility and proliferation. (A) Ormeloxifene lowers mobile proliferation of Caski and SiHa cells. Caski and SiHa cells had been treated with ormeloxifene (10, 20, 25?M) for 48?mTS and hours technique was utilized to determine proliferation and absorbance was measured in 490?nm. Results had been normalized to the automobile control (ETOH). Mistake bars display SEM, n?=?3. *p?0.05. PR-104 (B) Development kinetics through xCELLigence RTCA. Caski and SiHa PR-104 cell lines had been treated with 20?M ormeloxifene and development kinetics (price of real-time proliferation) was measured. (C,D) Ormeloxifene inhibits clonogenic potential of cells. (C) Cells demonstrated inhibited colony developing capability after 15 times of ormeloxifene treatment. Outcomes were normalized towards the ETOH control. Mistake bars display SEM, n?=?3. *p?0.05. (D) Qualitative representation of inhibited clonogenecity of cells. Pictures were used at 200X. (E) Ormeloxifene reduced the mobile migration and invasion. Cells had been treated with ormeloxifene for 24?pictures and hours were taken in 100X. Both cells show very clear inhibition of invasion and motility verified by Boyden chamber technique. (F) Motility kinetics through xCELLigence RTCA. Real-time intrusive and migratory properties of Caski and SiHa cells were also verified using xCELLigence system. Ormeloxifene induces cell loss of life through mitochondrial intrinsic pathway Reduced mitochondrial membrane potential (MMP).
Cell fusion is an extremely regulated biological process that occurs less than both physiological and pathological conditions. to the initiation, invasion, and metastasis of tumor. The phenotypic characteristics of hybrids are based on the phenotypes of parental cells, and the fusion of tumor cells with varied forms of microenvironmental fusogenic cells is definitely concomitant with phenotypic heterogeneity. This review shows the types of fusogenic cells in tumor microenvironment that can fuse with tumor cells and their specific significance and summarizes the various microenvironmental factors influencing tumor cell fusion. This review may be used as a reference to develop strategies for long term study on tumor cell fusion and the exploration of cell fusion-based antitumor therapies. 1. Intro Cell fusion is definitely a process that two or more cells become one by membrane fusion [1, 2]. Cell fusion is essential for fertilization, organ development, Galidesivir hydrochloride immune response, cells restoration, and regeneration under physiological conditions [3, 4]. In some pathological processes, such as illness and tumor progression, aberrant cell fusion happens regularly . As a major public health problem, malignant tumor is definitely a leading cause of death worldwide [6, 7]. Therefore, continued medical and basic research is required to fight against tumor. Cell fusion participates in processes associated with tumor initiation and progression [8, 9]. The presumption that cell fusion takes on critical tasks in tumor appears since it was postulated by Otto Aichel in 1911 . Tumor may originate from the build up of chromosomal abnormalities, such as the formation of aneuploidy or tetraploidy, which can cause the chromosomal damage and genetic instability and result in the malignant transformation of cells [11, 12], Galidesivir hydrochloride and cell fusion is an important way to generate polyploid cells [13, 14]. During tumor progression, cell fusion is definitely involved in tumor stem cell formation [9, 15], high invasiveness acquisition , tumor microenvironment (TME) redesigning , epithelialCmesenchymal transition (EMT) , drug resistance , and tumor angiogenesis , which are closely related to the growth, invasion, and metastasis of tumor. Earlier researches on the relationship between cell fusion and tumor focused on the part of cell fusion in tumor stem cell origination and tumor metastasis. Tumor stem cells possess the ability to initiate a heterogeneous tumor and show apparent changes in behavior associated with metastasis and recurrence [20, 21], which are the main causes of human tumor deaths [22, 23]. Tumor stem cells reportedly originate from primitive progenitor cells with cancerous mutations  or from normal stem cells with phenotypic changes or gene mutations . An increasing number of studies indicate the origination of tumor stem cells is definitely closely related to cell fusion and that bone marrow-derived stem cells fuse with somatic cells or tumor cells to produce tumor stem cells [26C28]. In addition, tumor cells fuse with tumor cells or additional somatic cells to generate cross cells INSR that possess the genetic characteristics of both parental cells, leading to the apparent variance of the biological behaviors of tumor cells, such as decreased adhesion, enhanced invasion and migration, increased drug resistance, and enhanced proliferation and Galidesivir hydrochloride antiapoptotic ability [29C31]. Overall, cell fusion participates in the initiation of tumor stem cells and malignancy transformation of tumor cells, resulting in the recurrence and metastases of tumor. TME is a complex dynamic system that includes tumor cells, the surrounding epithelial cells [32, 33], stromal cells composed of fibroblasts, immune cells, vascular endothelial cells, pericytes, adipocytes, bone marrow mesenchymal stromal cells, cytokines, vascular cells, and the extracellular matrix . Tumor cells interact with the surrounding stroma, exchange info, and dynamically remodel the microenvironment, Galidesivir hydrochloride therefore creating a microenvironment conducive to events such as tumor angiogenesis, proliferation, invasion, metastasis, and restorative resistance [33, 35, 36]. Moreover, the factors.
Supplementary MaterialsSupplementary Information 41467_2018_8154_MOESM1_ESM. proteins kinases exhibiting changed appearance and/or phosphorylation in Src-transformed mammary epithelial cells. A built-in siRNA screen recognizes nine kinases, including SGK1, to be needed for Src-induced change. Accordingly, we discover that Src favorably regulates SGK1 appearance in triple harmful breasts cancers cells, which exhibit FITC-Dextran a prominent signalling network governed by Src family kinases. Furthermore, combined inhibition of Src and SGK1 reduces colony formation and xenograft growth more effectively than either treatment alone. Therefore, this approach not only provides mechanistic insights into oncogenic transformation but also aids the design of improved therapeutic strategies. Introduction While great progress has been made in characterizing downstream signaling mechanisms of specific tyrosine kinase oncogenes, most of this work has focused on well-established signaling pathways, such as the Ras/MAPK, PI3K/Akt, and JAK/Stat pathways1. This continues despite data from cancer genome sequencing analyses, mass spectrometry (MS)-based proteomics and functional genomic screens highlighting involvement of many poorly-characterized protein kinases in cell transformation2. Consequently, our understanding of oncogenic kinase signaling is clearly limited and likely underestimates the complexity of downstream signaling events and their functional functions. Src was the first cellular proto-oncogene to be identified3 and is negatively regulated by phosphorylation on FITC-Dextran a conserved C-terminal tyrosine residue (Y527 and Y530 in poultry and individual Src, respectively), mediated by C-terminal CTNND1 Src kinase (Csk). This promotes development of a shut, inactive conformation where in fact the phosphorylated tyrosine residue is certainly engaged with the src FITC-Dextran homology (SH)2 area. Reflecting this, the Src Con527F mutant is active and exhibits transforming activity4 constitutively. While Src mutations in individual cancers are uncommon, elevated Src activity and appearance takes place in a number of malignancies, including breasts, non-small cell lung, digestive tract, and pancreatic malignancies, where it correlates with poor mediates or prognosis resistance to specific therapies5C9. Reflecting this, many Src-directed targeted remedies are in scientific studies in solid malignancies presently, like the tyrosine kinase inhibitors saracatanib, bosutinib, and dasatinib. Nevertheless, disease response or stabilization pursuing treatment with Src Tyrosine Kinase Inhibitors (TKIs) continues to be generally limited by little subsets of sufferers10, highlighting the necessity for a larger knowledge of Src-induced change and id of biomarkers that anticipate patient reaction to such therapies. Src signaling regulates a number of natural endpoints, including cell proliferation, success, adhesion, migration, and invasion11,12, and many strategies have been useful to interrogate substrates, signaling pathways and transcriptional applications governed by this oncogene. Early function exploited monoclonal antibody era and/or appearance cloning methods to recognize Src substrates13,14, while transcript profiling provides identified gene appearance applications connected with cell routine control, cytoskeletal firm, cell adhesion, and motility to be governed by Src15C17. Significantly, this function continues to be complemented and expanded by the use of an immunoaffinity-coupled MS-based proteomics workflow significantly, where tryptic tyrosine-phosphorylated peptides are enriched to MS analysis18 prior. Application of the method of Src-transformed fibroblasts and cancers cells FITC-Dextran exhibiting high degrees of Src activity provides highlighted the variety of proteins classes which are tyrosine-phosphorylated upon Src-induced change, ranging from particular kinases and phosphatases to GEFs, Spaces, and scaffolds, and uncovered novel processes governed by Src such as for example RNA maturation19C23. Despite these developments in our knowledge of Src-induced oncogenesis, the proteins kinase systems and pathways that control the pleiotropic ramifications of energetic Src stay badly characterized, because the proteomic strategies applied so far have focused FITC-Dextran on the tyrosine phosphoproteome, and do not provide insights into the expression or activation status of the large numbers of non-tyrosine phosphorylated kinases that lie downstream..
Aim To successfully translate magnetically mediated cell targeting from bench to bedside, there’s a have to systematically measure the potential undesireable effects of magnetic nanoparticles (MNPs) getting together with therapeutic cells. that MNPs at doses necessary for targeting did not induce significant adverse effects on structural integrity and functionality of primary endothelial cells C potential cell therapy vectors. transfection reagent according to the manufacturers protocol (BamaGen BioScience, MD, MDL 28170 USA). The same Gen-Drill transfection agent was used to introduce green fluorescent protein (GFP)-tubulin plasmid to visualize microtubules. Cells expressing fluorescent EYFP–actin or GFP-tubulin were loaded overnight with BODIPY?564/570 nm MNPs 24 h post-transfection. Before microscopy imaging, cells were rinsed vigorously with Ca2+ and Mg2+ made up of PBS to Il1a wash out MNPs not taken up by cells and kept in a modified Krebs buffer: 137 mM NaCl, 5 mM KCl, 1 mM KH2PO4, HEPES 20 mM, pH 7.4, 1 mM MgCl2, 2mM CaCl2, 10 mM glucose. To visualize endoplasmic reticulum (ER), cells were first loaded overnight with BODIPY?564/570 MNPs. The next day noninternalized nanoparticles were removed by several intensive washings with Ca2+ and Mg2+ made up of PBS prior to labeling with 200 nM ER-Tracker Blue-White DPX (Ex/Em wavelengths 374/430 nm; Life Technologies, NY, USA). After 15-min incubation at room temperature in the dark, cells were rinsed and left in the last wash in a modified Krebs buffer described above for imaging. To visualize mitochondria, both packed and unloaded with nanoparticles, cells had been stained MDL 28170 with 24 nM MitoTracker Orange CM?Ros (Former mate/Em wavelengths 554/576 nm) and/or with 70 nM MitoTracker Green FM (Former mate/Em wavelengths 490/516 nm; Lifestyle Technology). After 15-min incubation at area temperature at night, MDL 28170 cells were still left and rinsed within the last clean for imaging. To show the proliferative condition, cells had MDL 28170 been tagged with 14 g/ml acridine orange (Former mate/Em wavelengths 500/526 nm; Lifestyle Technology), a membrane-permeable nucleic acidity binding dye, before imaging immediately. The microscopy research had been performed using Olympus FluoView FV1000 confocal laser beam checking inverted microscope (Olympus America. Inc., PA, USA), which enables parallel video imaging and micro-fluorimetry for monitoring modulations in intracellular calcium mineral focus and mitochondria membrane potential due to cell launching with nanoparticles. Differential disturbance contrast (DIC) choice allows 3D imaging of cells. Microscopy measurements of mobile free of charge calcium mineral RAECs seeded on MatTek glass-bottom dishes at full confluence were loaded with 2 M Fluo-4AM free calcium-sensitive dye (Ex/Em wavelengths 488/560 nm) in a altered Krebs buffer (see above). After 15-min incubation at 25C in the dark, cells were washed twice and kept in the buffer for an additional 15 min for stabilization. Cell examination revealed uniform distribution of Fluo-4AM throughout the cells, suggesting no compartmentalization of Fluo-4AM within the organelles. The average fluorescence intensity of Fluo-4AM measured over each tested cell was converted to Ca2+ concentration using the equation : [=?and are the Fluo-4 fluorescence intensity for Ca2+-lacking and Ca2+-saturation concentrations determined by permeabilization from the cells with 10 M Ionomycin in the current presence of 20 mM ethylene glycol tetraacetic acidity (EGTA) and 2 mM CaCl2, respectively. Dissociation continuous (Kd) for the Fluo-4/Ca organic has been used as 345 nM based on the manufacturer. To judge the quantity of calcium mineral released from ER solely, cells had been held in calcium-free buffer defined above to exclude extracellular calcium mineral influx. Prior to examination Just, RAECs had been additionally subjected to 2 g/ml oligomycin to stop the mitochondria adenosine triphosphate synthase to avoid energy-dependent calcium mineral sequestration through mitochondria Ca2+-uniporter. On the ultimate stage of cell permeabilization with Ionomycin, calcium-free extracellular buffer was changed using the buffer formulated with 2 mM CaCl2 accompanied by chelating Ca2+ with 20 mM EGTA. Evaluation of mitochondria mass & mitochondria membrane potential RAECs had been loaded with non-fluorescent nanoparticles for 24 h ahead of measurements. The packed cells had been washed out many times to eliminate noninternalized MNPs. After that cells were re-suspended and trypsinized in modified Krebs buffer for labeling with fluorescent dyes. MitoTracker Green FM (70 nM; Ex girlfriend or boyfriend/Em wavelengths 490/516 nm; Lifestyle Technology) fluorescence continues to be utilized to designate mitochondria. Cells had been noticed using 60 NA 1.42 PLAPON essential oil goal. Mitochondria membrane potential was analyzed on BD Accuri C6 stream cytometer (BD Biosciences) with the cells dual labeling with 70nM MitoTracker Green FM and 24 nM MitoTracker Orange CM?Ros (Ex girlfriend or boyfriend/Em wavelengths 554/576 nm; Lifestyle Technologies), the fluorescence which had been utilized being a way of measuring mitochondrial MDL 28170 mitochondria and mass internal membrane potential, correspondingly. Treatment of the cells with 1 M of carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), which uncouples mitochondria oxidative phosphorylation producing a collapse of membrane potential, was utilized as.
Supplementary Materialsijms-21-03148-s001. knockdown of Handbag3 led to increased viral produces in HEK293T cells. Hence, these data indicated a poor regulation function of Handbag3 during PRV lytic infections. Collectively, our findings revealed a novel molecular mechanism on host protein degradation induced by PRV pUL56. Moreover, we identified BAG3 as a host restricted protein during PRV lytic contamination in cells. gene, alpha-herpesvirus, WW-domain, PPxY motif, leucine 1. Introduction Pseudorabies computer virus (PRV), which is one of the most important swine pathogens, belongs to the subfamily and contains a large (approximately 150 kb) double-stranded DNA genome. The virion is composed of a complex structure including a linear genome surrounded by nucleocapsid, proteinaceous tegument, and a lipid bilayer envelope from your inner side to the outer side, in addition to some host proteins (e.g., Rab GTPases) [1,2]. During the lytic contamination of alpha-herpesviruses, the interplay between computer virus and host proteins contributes to a diversity of influences around the viral life cycle (e.g., viral access, replication, envelope, and egress) [2,3]. Host BCL-2-associated athanogene (BAG) 3 is usually a co-chaperone protein of the BAG protein family, and was first isolated and identified as a Bcl-2 binding protein [4,5]. The family talk about a conserved Handbag domains on the C-terminus [5 extremely,6]. Among these family members proteins, Handbag3 may be the only one which has an N-terminal WW-domain [5,6,7]. To time, two Handbag3 variations (81IIe and 81Met) have already been uncovered in mice. The novel variant (81Met Handbag3) was reported lately, as well as the known degree of genetic variation was sufficient to confer susceptibility to necrosis in mice . The connections between Handbag3 and PPxY theme filled with viral proteins is normally a well-defined event occurring throughout a viral an infection [7,9,10]. This connections is involved with modulation from the viral lifestyle routine, and such results have been seen in alpha-herpesviruses, filoviruses, arenaviruses, and coronaviruses [7,9,10,11,12]. A depletion of Phthalic acid Handbag3 results within an inhibition of varicella-zoster trojan (VZV) replication . Furthermore, Handbag3 is necessary for the temporal legislation and deposition of instant early gene items for augmenting the replication Rabbit Polyclonal to BAGE3 of herpes virus (HSV) 1 via an connections between ICP0 and Handbag3 . These results suggest that Handbag3 can facilitate the replication of alpha-herpesviruses by impacting the instant early gene items. On the other hand, the connections between Handbag3 and PPxY theme filled with the matrix proteins VP40 in Ebola trojan and Marburg trojan or Z proteins in Lassa fever trojan suppresses the budding of VP40 Phthalic acid virus-like contaminants. Thus, Handbag3 counteracts the egress and pass on of viral contaminants, which suggests a poor regulatory function [7,11]. Furthermore, the inhibition from the gene by RNA disturbance (RNAi) can result in a substantial suppression of SARS-CoV replication . Hence, web host Handbag3 could be involved with regulating the viral lifestyle routine via different strategies, which leads to the positive or a poor influence on viral proliferation during multiple procedures of Phthalic acid lytic an infection. PRV type II membrane proteins UL56 (pUL56) provides four PPxY motifs , which represents a potential Handbag3 interactor. Lately, PRV pUL56 continues to be defined as a virulence-associated aspect that plays a part in Phthalic acid viral dissemination in the rodent anxious program . The HSV1 pUL56 is normally mixed up in maintenance.
Unpleasant processing procedures in piglets such as for example tail docking, castration, and teeth clipping are an growing pet welfare concern. 0.0416) and 0.5 mg/kg of firocoxib (= 0.0397). From control to weaning, litters of sows getting 2.0 mg/kg firocoxib gained more excess weight than litters of sows that received 0.5 mg/kg (= 0.008) or 1.0 mg/kg (= 0.005). No indications of non-steroidal anti-inflammatory medication toxicity had been observed on study of the kidney, liver organ, stomach, and little intestine, and concentrations of firocoxib as well as the descyclopropylmethyl metabolite had been below the limit of recognition (0.01 g/g) in every tissues examined from sows and piglets. These results reveal that maternal delivery of firocoxib to suckling piglets before tail docking and castration may securely reduce processing-induced tension and enhance creation by raising weaning weights. = 4/treatment)16161616161616161616161616No. of piglets (= 36/treatment)144144144144144144144144144144144144144SowsBody pounds determinationXRandomizationXTreatmentXFirocoxib 0.5 mg/kg = 4Firocoxib 1.0 mg/kg = 4Firocoxib 1.5 mg/kg = 4Firocoxib 2.0 mg/kg = 4Blood test for firocoxibXXXXXXXXXXXNecropsy and cells collectionXNursing pigletsTime in accordance with control (h)?30?6?4?202618426690Body pounds determinationXADGXCastration, tail docking and teeth clipping (male piglets)XBlood sample (= 3 piglets/litter)XXXXXXXXXXXFirocoxib determinationXXXXXXXXXXXCortisol determinationXXXXXXXNecropsy and cells collection (= 3 piglets/litter)X Open up in another window H100 Pets Twenty-two pregnant Yorkshire Landrace sows (mean SEM bodyweight, 250.3 7.61 kg) which were approximately 1 wk before farrowing were sourced from a industrial swine farm (Desk 2). All scholarly research pets H100 were bred towards the same boar except sow 16149 and sow 16175. The boar range was Maxgro (Hermitage NGT genetics, Gwynne, Abdominal, Canada). Particularly, the male part was Pietrain and the feminine part was a 5 method mix of Berkshire, Hamp, Duroc, Landrace, and Yorkshire. The sows had been Hermitage Lineage-F1. Each sow was examined with a vet to verify that she was pregnant and healthy. A distinctive numerical ear label (Allflex Global Ear Tags, Allflex USA, Inc., DFW Airport terminal, TX) was put into the right hearing of every sow for recognition. The sows had been housed inside Rabbit Polyclonal to 5-HT-6 a industrial swine procedure at MVS (Western Point, NE) relative to the suggestions in the Guidebook for the Treatment and Usage of Agricultural Pets in Agricultural Make use of and Study and Teaching (Federation of Pet Technology, 2010). Sows had been put into Quad- or Euro-style farrowing stalls (Thorp Tools, Thorp, WI), based on availability. Of stall type Regardless, each sow was housed inside a farrowing cage calculating 0.6 m 2.1 m. Euro and Quad crates had piglet creep regions of 7.0 and 6.4 m2, respectively. After farrowing, a temperature lamp was offered on one part from the creep H100 region for the piglets in H100 each cage. All sows had been fed a diet plan that fulfilled or exceeded Country wide Study Council (NRC, 2012) nutritional requirements and drinking water was provided advertisement libitum. At the proper period of research commencement, there is no energetic disease pressure from porcine reproductive and respiratory symptoms, porcine epidemic diarrhea disease, or swine influenza disease. Table 2. Research population doses and information of firocoxib administered to lactating sows via intramuscular injection at 0.5, 1.0, 1.5, or 2.0 mg/kg bodyweight = 4 sows per group; Desk 2). Study employees had been masked to treatment group. An example size of 4 sows was chosen to spell it out the pharmacokinetics of firocoxib predicated on concepts defined by Riviere (2011). For the assessment of plasma cortisol concentrations and normal daily gain in bodyweight (ADG), an example size of 36 piglets per treatment was determined to supply Statistical Power of 80% (0.8), assuming an alpha of 0.05, sigma of 0.54, and delta of 0.20. During research commencement (to sediment the proteins pellet. Pursuing centrifugation, the supernatant was poured into cell tradition pipes and evaporated to dryness inside a Turbovap focus evaporator at 48 C. The pipe contents had been reconstituted with 150 L 25% acetonitrile and used in autosampler vials built with 300-L cup inserts. The examples had been centrifuged at 770 before liquid chromatographyCmass spectroscopy (LCCMS) evaluation. Twelve calibration spikes had been prepared in empty porcine plasma in the focus selection of 1 to 5,000 ng/mL for the examples through the sows. The examples through the piglets had been analyzed utilizing a.