The Rbf1, Hfl1 and Dbp4 of Candida albicans regulate common as well as transcription factor-specific mitochondrial and other cell activities

BACKGROUND

Our interest in Candida albicans mitochondria began with the identification of GOA1. We demonstrated its role in cell energy production, cross-talk among mitochondria and peroxisomes, non-glucose energy metabolism, maintenance of stationary phase growth, and prevention of premature apoptosis. Its absence results in avirulence. However, what regulated transcription of GOA1 was unknown.

RESULTS

To identify transcriptional regulators (TRs) of GOA1, we screened a C. albicans TF knockout library (TRKO) and identified Rbf1p, Hfl1p, and Dpb4p as positive TRs of GOA1. The phenotypes of each mutant (reduced respiration, inability to grow on glycerol, reduced ETC CI and CIV activities) are reasonable evidence for their required roles especially in mitochondrial functions. While the integration of mitochondria with cell metabolic activities is presumed to occur, there is minimal information on this subject at the genome level. Therefore, microarray analysis was used to provide this information for each TR mutant. Transcriptional profiles of Rbf1p and Hfl1p are more similar than that of Dpn4p. Our data demonstrate common and also gene-specific regulatory functions for each TR. We establish their roles in carbon metabolism, stress adaptation, cell wall synthesis, transporter efflux, peroxisomal metabolism, phospholipid synthesis, rRNA processing, and nuclear/mtDNA replication.

CONCLUSIONS

The TRs regulate a number of common genes but each also regulates specific gene transcription. These data for the first time create a genome roadmap that can be used to integrate mitochondria with other cell processes. Of interest, the TRs are fungal-specific, warranting consideration as antifungal drug targets.

Antifungal drug discovery: the process and outcomes

New data suggest that the global incidence of several types of fungal diseases have traditionally been under-documented. Of these, mortality caused by invasive fungal infections remains disturbingly high, equal to or exceeding deaths caused by drug-resistant tuberculosis and malaria. It is clear that basic research on new antifungal drugs, vaccines and diagnostic tools is needed. In this review, we focus upon antifungal drug discovery including in vitro assays, compound libraries and approaches to target identification. Genome mining has made it possible to identify fungal-specific targets; however, new compounds to these targets are apparently not in the antimicrobial pipeline. We suggest that 'repurposing' compounds (off patent) might be a more immediate starting point. Furthermore, we examine the dogma on antifungal discovery and suggest that a major thrust in technologies such as structural biology, homology modeling and virtual imaging is needed to drive discovery.

GluR6-FasL-Trx2 mediates denitrosylation and activation of procaspase-3 in cerebral ischemia/reperfusion in rats

Global cerebral ischemia/reperfusion (I/R) facilitates the activation of procaspase-3 and promotes apoptosis in hippocampus. But the mechanisms have remained uncharacterized. Protein S-nitrosylation and denitrosylation is an important reversible posttranslational modification, which is a common mechanism in signal transduction and affects numerous physiological and pathophysiological events. However, it is not known whether S-nitrosylation/denitrosylation modification of procaspase-3 serves as a component of apoptosis and cell death induced by cerebral I/R. Here we show that procaspase-3 is significantly denitrosylated and activated after I/R in rat hippocampus. NS102, a glutamate receptor 6 (GluR6) antagonist, can inhibit the denitrosylation of procaspase-3 and diminish the increased Fas ligand (FasL) and thioredoxin (Trx)-2 expression induced by cerebral I/R. Moreover, downregulation of FasL expression by antisense oligodeoxynucleotides inhibits the denitrosylation and activation of procaspase-3. Auranofin, a TrxR inhibitor or TrxR2 antisense oligodeoxynucleotide, has similar effects. In primary hippocampal cultures, Lentiviral-mediated knockdown of FasL and TrxR2 before the oxygen and glucose deprivation/reoxygenation further verifies that FasL and TrxR2 are involved in the denitrosylation of procaspase-3. In situ TUNEL staining and cresyl violet staining validate that inhibiting denitrosylation of procaspase-3 may exert neuroprotective effect on apoptosis and cell death induced by cerebral I/R in hippocampal CA1 pyramidal neurons. This is the first evidence that cerebral I/R mediates procaspase-3 denitrosylation and activation through GluR6-FasL-Trx2 pathway, which leads to neuronal apoptosis and cell death.

Combination of targeting gene-viro therapy with recombinant Fowl-pox viruses with HN and VP3 genes on mouse osteosarcoma

BACKGROUND

Osteosarcoma is an aggressive cancerous neoplasm arising from primitive transformed cells of mesenchymal origin that exhibit osteoblastic differentiation and produce malignant osteoid. With the rapid development of tumor molecular biology, gene and viral therapy, a highly promising strategy for the treatment, has shown some therapeutic effects.

OBJECTIVES

To study the strategy of cooperative cancer gene therapy, previously, we explored the antitumor effects of recombinant Fowl-pox viruses (FPVs) with both HN (hemagglutinin-neuramidinase) and VP3 genes on mouse osteosarcoma.

MATERIALS AND METHODS

We constructed vFV-HN, vFV-VP3 and vFV-HN-VP3 inserting CAV VP3 gene, NDV HN gene into fowlpox virus. S180 osteosarcoma were transfected with Recombinant Fowl-pox viruses (FPVs). These cell lines stably expressing tagged proteins were selected by culturing in medium containing puromycin (2 µg/ml) and confirmed by immunoblotting and immunostaining. S180 osteosarcoma model with BALB/c mice and nude mice were established and the vFPV viruses as control, vFV-HN, vFV-VP3, vFV-HN-VP3 were injected into the tumor directly. The rate of tumor growth, tumor suppression and the sialic acid levels in serum were examined and the tumor tissues were analyzed by the method of immunohistochemistry. Flow cytometric analysis was performed using a FACSCalibur flow cytometer. A total of 100,000 events were analyzed for each sample and the experiment was repeated at least twice.

RESULTS

Our data indicated that vFV-HN, vFV-VP3 and vFV-HN-VP3 all had growth inhibition effects, the inhibition rate of vFV-HN-VP3 group was 51.7%, which was higher than that of vFV-HN, vFV-VP3 group and control group (p < 0.01). The sialic acid level of vFV-HN-VP3 group in mouse serum was 4.22±0.27 mmol/l, which was lower than that of other groups (p < 0.01).

CONCLUSIONS

These results suggest that genes into mouse osteosarcoma cancer cells can cause cell a specificity anti-tumor immune activity, suppress tumor growth, and increase the survival rate of the tumor within host.

A comparison of the clinical characteristics of women with recurrent major depression with and without suicidal symptomatology

BACKGROUND

The relationship between recurrent major depression (MD) in women and suicidality is complex. We investigated the extent to which patients who suffered with various forms of suicidal symptomatology can be distinguished from those subjects without such symptoms.

METHOD

We examined the clinical features of the worst episode in 1970 Han Chinese women with recurrent DSM-IV MD between the ages of 30 and 60 years from across China. Student's t tests, and logistic and multiple logistic regression models were used to determine the association between suicidality and other clinical features of MD.

RESULTS

Suicidal symptomatology is significantly associated with a more severe form of MD, as indexed by both the number of episodes and number of MD symptoms. Patients reporting suicidal thoughts, plans or attempts experienced a significantly greater number of stressful life events. The depressive symptom most strongly associated with lifetime suicide attempt was feelings of worthlessness (odds ratio 4.25, 95% confidence interval 2.9-6.3). Excessive guilt, diminished concentration and impaired decision-making were also significantly associated with a suicide attempt.

CONCLUSIONS

This study contributes to the existing literature on risk factors for suicidal symptomatology in depressed women. Identifying specific depressive symptoms and co-morbid psychiatric disorders may help improve the clinical assessment of suicide risk in depressed patients. These findings could be helpful in identifying those who need more intense treatment strategies in order to prevent suicide.

A survey of peptides with effective therapeutic potential in Alzheimer's disease rodent models or in human clinical studies

Alzheimer’s disease (AD) is a devastating neurodegenerative disorder and the most common cause of dementia. Today, only palliative therapies are available. The pathological hallmarks of AD are the presence of neurofibrillary tangles and amyloid plaques, mainly composed of the amyloid-β peptide (Aβ), in the brains of the patients. Several lines of evidence suggest that the increased production and/or decreased cleavage of Aβ and subsequent accumulation of Aβ oligomers and aggregates play a fundamental role in the disease progress. Therefore, substances which bind to Aβ and influence aggregation thereof are of great interest. A wide range of Aβ binding peptides were investigated to date for therapeutic purposes. Only very few were shown to be effective in rodent AD models or in clinical studies. Here, we review those peptides and discuss their possible mechanisms of action.

Bioinformatics analysis reveals potential candidate drugs for psychological stress in ovarian cancer

BACKGROUND

Women with ovarian cancer may be at increased risk for psychological distress around the time of diagnosis relative to patients diagnosed with other cancers, because of the seriousness of the disease. However, the molecular mechanism of this effect is far from clear.

AIM

We sought to investigate the influence of psychological status in regulating gene expression among women with primary ovarian cancer and to identify the small molecules which exhibit similar effects with different psychological status.

MATERIALS AND METHODS

DNA microarray analyses of 10 ovarian carcinomas (GSE9116, downloaded from GEO) identified 916 human transcripts that were differentially expressed in tumors from patients with high depression relative to grade-and stage-matched tumors from low depression patients, and pathways related to immune system were dysfunctional.

RESULTS

Our results suggest that psychosocial stress is related to impaired immunity in ovarian cancer patients. Besides, we identified a group of small molecules which can be exploited as adjuvant drug to improve therapeutic effect for ovarian cancer, such as MS-275 and adiphenine.

CONCLUSIONS

Our findings may be useful for the development of management strategies for psychological distress, and we suggest that there is a need for improvement in the quality of life of cancer outpatients being treated with chemotherapy.

Efficacy of folic acid supplementation in stroke prevention: new insight from a meta-analysis

AIMS

  There are growing data and a continuing controversy over the efficacy of folic acid supplementation in stroke prevention. We conducted a meta-analysis based on relevant, up-to-date published randomised trials to further examine this issue.

METHODS

  Relative risk (RR) was used to measure the effect of folic acid supplementation on risk of stroke with a fixed-effects model.

RESULTS

  Overall, folic acid supplementation reduced the risk of stroke by 8% (n = 55,764; RR: 0.92; 95% CI: 0.86-1.00, p = 0.038). In the 10 trials with no or partial folic acid fortification (n = 43,426), the risk of stroke was reduced by 11% (0.89; 0.82-0.97, p = 0.010). Within these trials, a greater beneficial effect was observed among trials with a lower percent use of statins [≤ 80% (median); 0.77; 0.64-0.92, p = 0.005], and a meta-regression analysis also suggested a positive dose-response relationship between percent use of statins and log-RR for stroke associated with folic acid supplementation (p = 0.013). A daily dose of 0.4-0.8mg folic acid appeared to be adequate for stroke prevention in comparison with larger doses. In the remaining five trials conducted in populations with folic acid fortification (n = 12,338), folic acid supplementation had no effect on stroke risk (1.03; 0.88-1.21, 0.69).

CONCLUSIONS

  Our analysis indicated that folic acid supplementation is effective in stroke prevention in populations with no or partial folic acid fortification. In addition, a greater beneficial effect was observed among trials with a lower percent use of statins. Our findings underscore the importance of identifying target populations that can particularly benefit from folic acid therapy.

Metabotropic glutamate subtype 7 and 8 receptors oppositely modulate cardiac nociception in the rat nucleus tractus solitarius

Recent study from our laboratory has indicated that microinjection of glutamate into the nucleus tractus solitarius (NTS) facilitates the cardiac-somatic reflex induced by pericardial capsaicin. Further, N-methyl-d-aspartate (NMDA) receptors and metabotropic glutamate receptors (mGluRs) mediate this function. However, the roles of the individual receptor subtypes or subunits in modulating cardiac nociception are unknown. Among the three groups of mGluRs, group III mGluRs are the primary mGluR subtype expressed in visceral afferent neurons in the NTS. The present study examined the roles of group III mGluRs and their subtype 7 and 8 receptors (mGluR7 and mGluR8) in modulating the cardiac-somatic reflex induced by pericardial capsaicin, which was monitored by recording electromyogram (EMG) activity from the spinotrapezius muscle in anesthetized rats. Intra-NTS microinjection of a group III mGluR agonist, l-(+)-2-Amino-4-phosphonobutyric acid (l-AP4, at 1, 10, and 20 nmol) or a selective mGluR7 agonist, N,N'-diphenylmethyl-1,2-ethanediamine dihydrochloride (AMN082, at 1, 2, and 4 nmol) both decreased the EMG response in a dose-dependent manner. This decrease was inhibited by the group III mGluR antagonist (RS)-α-Methylserine-O-phosphate (MSOP, at 20 nmol). In contrast, intra-NTS microinjection of a selective mGluR8 agonist, (S)-3, 4-dicarboxyphenylglycine (DCPG, at 6 and 8 nmol), significantly increased the EMG response above control levels. This effect was eliminated by intra-NTS MSOP and by vagal deafferentation. These data suggest that group III mGluRs and mGluR7 in the NTS display an inhibitory effect, while mGluR8 displays a facilitatory effect in modulating cardiac nociception, and this facilitatory effect is dependent on vagal afferents.

Chemical lesioning and glutamate administration reveal a major role for the nucleus tractus solitarius in the cardiac-somatic reflex in rats

Many patients suffer from secondary muscle hyperalgesia after experiencing angina pectoris. In this study, we examined the role of the nucleus tractus solitarius (NTS) and glutamate receptors in modulating cardiac-evoked muscle hyperalgesia induced by pericardial capsaicin, which was monitored by recording electromyogram (EMG) activity from the spinotrapezius muscle in the anesthetized rat. Unilateral chemical lesioning of the commissural NTS with the neurotoxin ibotenic acid significantly depressed the cardiac-somatic reflex; the EMG responses decreased to 56.4 ± 6.9% of that of the controls (5 of 5). Microinjection of the excitatory amino acid glutamate, at 10, 20, and 50 nmol, into the commissural NTS increased the EMG response, in a dose-dependent manner, to 116.9 ± 4.9%, 143.9 ± 10.2%, and 214.2 ± 15.8% (n=8), respectively, of that of the controls. In contrast, microinjection of the N-methyl-D-aspartate (NMDA) receptor antagonist (+)-5-methyl-10, 11-dihydro-5H-dibenzo [a, d]-cyclohepten-5,10-imine maleate (MK-801) at 4 and 6 nmol, decreased the EMG response to 45.2 ± 10.6% and 36.8 ± 14.3%, respectively, of that of the controls (n=8 for each dose). Similarly, the metabotropic glutamate receptor (mGluR) antagonist (RS)-a-methyl-4-carboxyphenylglycine (MCPG), at 2.5 and 5 nmol, decreased the EMG response to 65.2 ± 16.3% and 57.0 ± 4.2%, respectively, of that of the controls. When a combination of MK-801 and MCPG was administrated, the EMG response further decreased to 22.5 ± 13.2% (n=6) of that of the controls. However, administration of a non-NMDA receptor antagonist 6, 7-dinitroquinoxaline-2, 3-dione (DNQX), at 2 and 5 nmol, had no effect on the EMG response. These results suggest that the NTS is involved in the facilitation of the cardiac-somatic reflex, and that the NMDA receptor and mGluRs play an important role in mediating this effect.

Optimization of complex conditions by response surface methodology for APAM-oil/water emulsion removal from aqua solutions using nano-sized TiO2/Al2O3 PVDF ultrafiltration membrane

This paper studies the cumulative effect of various parameters, namely anionic polyacrylamide (APAM) concentration, oil concentration, pH, trans-membrane pressure (TMP), and total dissolved solid (TDS), and obtains optimal parameters for the minimum relative flux (J/J(0)) declining in aqueous solutions with response surface methodology (RSM). In order to analyze the mutual interaction and optimal values of parameters affecting ultrafiltration, a central composite rotatable design (CCRD), one method of RSM, was employed. The analysis of variance (ANOVA) of the cubic polynomial model demonstrated that this model was highly significant and reliable. The results show that the effect of APAM and oil on J/J(0) has an inverse trend with pH value increasing. Moreover, the mutual interaction of initial APAM (oil) concentration (C(APAM(oil))) and pH (TMP) were negligible, while the mutual interaction of C(APAM) and C(oil) has an obvious effect, i.e. the effect of initial feed C(APAM) became more important at higher values of initial feed C(oil), and the J/J(0) was only about 4%. The favorable operate conditions in this ultrafiltration process were at low C(APAM), C(oil), pH, and TMP, which agreed with the conclusions of many authors, while considering water production, C(APAM) and C(oil) < 50 mg/L, pH < 4, and TMP < 0.075 MPa could be accepted.

Isotherm and kinetic behavior of adsorption of anion polyacrylamide (APAM) from aqueous solution using two kinds of PVDF UF membranes

To determine the isotherm parameters and kinetic parameters of adsorption of anion polyacrylamide (APAM) from aqueous solution on PVDF ultrafiltration membrane (PM) and modified PVDF ultrafiltration membrane (MPM) is important in understanding the adsorption mechanism of ultrafiltration processes. Effect of variables including adsorption time, initial solution concentration, and temperature were investigated. The Redlich-Peterson equation of the five different isotherm models we chose was the most fitted model, and the R(2) was 0.9487, 0.9765 for PM and MPM, respectively; while, the pseudo-first-order model was the best choice among all the four kinetic models to describe the adsorption behavior of APAM onto membranes, suggesting that the adsorption mechanism was a chemical and physical combined adsorption on heterogeneous surface. The thermodynamic parameters were also calculated from the temperature dependence (Δ(r)G(m)(θ), Δ(r)H(m)(θ), Δ(r)S(m)(θ)), which showed that the process of adsorption is not spontaneous but endothermic process and high temperature favors the adsorption.

Trichodermaketones A-D and 7-O-methylkoninginin D from the marine fungus Trichoderma koningii

Five new polyketide derivatives, 7-O-methylkoninginin D (1) and trichodermaketones A-D (2-5), together with four known compounds, koninginins A, D, E, and F, were isolated from the marine-derived fungus Trichoderma koningii. Trichodermaketones A (2) and B (3) are unprecedented polyketides with a bistetrafuran-containing tricyclic skeleton. The chemical structures and absolute configurations of compounds 1-5 were elucidated by comparing with literature data and extensive spectroscopic methods, including 2D NMR and CD spectroscopic analysis. Compounds 1-5 were evaluated for action against bacteria and fungi and for synergistic antifungal activity. Compound 2 showed synergistic antifungal activity against Candida albicans with 0.05 microg/mL ketoconazole.

Goa1p of Candida albicans localizes to the mitochondria during stress and is required for mitochondrial function and virulence

Using a Tn7 transposon library of Candida albicans, we have identified a mutant that exhibited sensitivity in drop plate assays to oxidants such as menadione and hydrogen peroxide. To verify the role of the mutated gene in stress adaptation, null mutants were constructed and phenotypically characterized. Because of its apparent functions in growth and oxidant adaptation, we have named the gene GOA1. Goa1p appears to be unique to the CTG subclade of the Saccharomycotina, including C. albicans. Mutants of C. albicans lacking goa1 (strain GOA31) were more sensitive to 6 mM H(2)O(2) and 0.125 mM menadione than the wild type (wt) or a gene-reconstituted (GOA32) strain. The sensitivity to oxidants correlated with reduced survival of the GOA31 mutant in human neutrophils and avirulence compared to control strains. Other phenotypes of GOA31 include reduced growth and filamentation in 10% serum, Spider, and SLAD agar media and an inability to form chlamydospores. Since Goa1p has an N-terminal mitochondrion localization site, we also show that green fluorescent protein-tagged Goa1p shows a mitochondrionlike distribution during oxidant or osmotic stress. Further, the inability of GOA31 to grow in medium containing lactate, ethanol, or glycerol as the sole carbon source indicates that the mitochondria are defective in the mutant. To determine how Goa1p contributes to mitochondrial function, we compared the wt, GOA32, and GOA31 strains for mitochondrial electrical membrane potential, respiration, and oxidative phosphorylation. We now show that GOA31, but not the wt or GOA32, had decreased respiration and mitochondrial membrane potential such that mutant cells are unable to drive oxidative phosphorylation. This is the first report in C. albicans of a respiratory defect caused by a loss of mitochondrial membrane potential.

Neonatal death in mice lacking cardiotrophin-like cytokine is associated with multifocal neuronal hypoplasia

Mice with null mutations of ciliary neurotrophic factor (Cntf) receptor alpha (Cntf-Ralpha), or cytokine-like factor 1 (Clf), one component of Cntf-II (a heterodimeric Cntf-Ralpha ligand), die as neonates from motor neuron loss affecting the facial nucleus and ventral horn of the lumbar spinal cord. Exposure to cardiotrophin-like cytokine (Clc), the other putative Cntf-II element, supports motor neuron survival in vitro and in ovo. Confirmation that Clc ablation induces an equivalent phenotype to Clf deletion would support a role for Clc in the functional Cntf-II complex. In this study, Clc knockout mice had decreased facial motility, did not suckle, died within 24 hours, and had 32% and 29% fewer motor neurons in the facial nucleus and lumbar ventral horn, respectively; thus, Clc is essential for motor neuron survival during development. The concordance of the Clc knockout phenotype with those of mice lacking Cntf-Ralpha or Clf bolsters the hypothesis that Clc participates in Cntf-II.

Expressed sequence tags from persimmon at different developmental stages

Persimmon (Diospyros kaki Thunb.) is an important fruit in Asian countries, where it is eaten as a fresh fruit and is also used for many other purposes. To understand the molecular mechanism of fruit development and ripening in persimmon, we generated a total of 9,952 expressed sequence tags (ESTs) from randomly selected clones of two different cDNA libraries. One cDNA library was derived from fruit of "Saijo" persimmon at an early stage of development, and the other from ripening fruit. These ESTs were clustered into 6,700 non-redundant sequences. Of the 6,700 non-redundant sequences evaluated, the deduced amino acid sequences of 4,356 (65%) showed significant homology to known proteins, and 2,344 (35%) showed no significant similarity to any known proteins in Arabidopsis databases. We report comparison of genes identified in the two cDNA libraries and describe some putative genes involved in proanthocyanidin and carotenoid synthesis. This study provides the first global overview of a set of genes that are expressed during fruit development and ripening in persimmon.

Nephrin mediates actin reorganization via phosphoinositide 3-kinase in podocytes

Nephrin is a slit diaphragm protein critical for structural and functional integrity of visceral glomerular epithelial cells (podocytes) and is known to be tyrosine phosphorylated by Src family kinases. We studied the role of phosphoinositide 3-kinase (PI3K), activated via the phosphorylation of nephrin, in actin cytoskeletal reorganization of cultured rat podocytes. Phosphorylation of rat nephrin by the Fyn kinase markedly increased its interaction with a regulatory subunit of PI3K. Stable transfection of rat nephrin in the podocytes with podocin led to nephrin tyrosine phosphorylation, PI3K-dependent phosphorylation of Akt, increased Rac1 activity, and an altered actin cytoskeleton with decreased stress fibers and increased lamellipodia. These changes were reversed with an inhibitor of PI3K and not seen when the nephrin-mutant Y1152F replaced wild-type nephrin. Rac1 and Akt1 contributed to lamellipodia formation and decreased stress fibers, respectively. Finally, in the rat model of puromycin aminonucleoside nephrosis, nephrin tyrosine phosphorylation, nephrin-PI3K association, and glomerular Akt phosphorylation were all decreased. Our results suggest that PI3K is involved in nephrin-mediated actin reorganization in podocytes. Disturbed nephrin-PI3K interactions may contribute to abnormal podocyte morphology and proteinuria.

High-throughput synergy screening identifies microbial metabolites as combination agents for the treatment of fungal infections

The high mortality rate of immunocompromised patients with fungal infections and the limited availability of highly efficacious and safe agents demand the development of new antifungal therapeutics. To rapidly discover such agents, we developed a high-throughput synergy screening (HTSS) strategy for novel microbial natural products. Specifically, a microbial natural product library was screened for hits that synergize the effect of a low dosage of ketoconazole (KTC) that alone shows little detectable fungicidal activity. Through screening of approximately 20,000 microbial extracts, 12 hits were identified with broad-spectrum antifungal activity. Seven of them showed little cytotoxicity against human hepatoma cells. Fractionation of the active extracts revealed beauvericin (BEA) as the most potent component, because it dramatically synergized KTC activity against diverse fungal pathogens by a checkerboard assay. Significantly, in our immunocompromised mouse model, combinations of BEA (0.5 mg/kg) and KTC (0.5 mg/kg) prolonged survival of the host infected with Candida parapsilosis and reduced fungal colony counts in animal organs including kidneys, lungs, and brains. Such an effect was not achieved even with the high dose of 50 mg/kg KTC. These data support synergism between BEA and KTC and thereby a prospective strategy for antifungal therapy.