Proteasome stress in skeletal muscle mounts a long-range protective response that delays retinal and brain aging.

Neurodegeneration in the central nervous system (CNS) is a defining feature of organismal aging that is influenced by peripheral tissues. Clinical observations indicate that skeletal muscle influences CNS aging, but the underlying muscle-to-brain signaling remains unexplored. In Drosophila, we find that moderate perturbation of the proteasome in skeletal muscle induces compensatory preservation of CNS proteostasis during aging. Such long-range stress signaling depends on muscle-secreted Amyrel amylase. Mimicking stress-induced Amyrel upregulation in muscle reduces age-related accumulation of poly-ubiquitinated proteins in the brain and retina via chaperones. Preservation of proteostasis stems from the disaccharide maltose, which is produced via Amyrel amylase activity. Correspondingly, RNAi for SLC45 maltose transporters reduces expression of Amyrel-induced chaperones and worsens brain proteostasis during aging. Moreover, maltose preserves proteostasis and neuronal activity in human brain organoids challenged by thermal stress. Thus, proteasome stress in skeletal muscle hinders retinal and brain aging by mounting an adaptive response via amylase/maltose.

Risk factors of postoperative major adverse cardiac events after radical cystectomy: implication of diastolic dysfunction.

Radical cystectomy, which is a standard treatment of muscle invasive and high-grade non-invasive bladder tumour, is accompanied with high rates of postoperative complications including major adverse cardiac events (MACE). Diastolic dysfunction is associated with postoperative complications. We evaluated perioperative risk factors including diastolic dysfunction related with MACE within 6 months after radical cystectomy. The 546 patients who underwent elective radical cystectomy were included. Diastolic dysfunction was defined as early transmitral flow velocity (E)/early diastolic mitral annulus velocity (e') > 15. Logistic regression analysis, Kaplan-Meier survival analysis and log-rank test were performed. MACE within 6 months after radical cystectomy developed in 43 (7.9%) patients. MACE was related with female (odds ratio 2.546, 95% confidence interval 1.166-5.557, P = 0.019) and diastolic dysfunction (odds ratio 3.077, 95% confidence interval 1.147-8.252, P = 0.026). The 6-month mortality were significantly higher in the MACE group, and hospital stay and intensive care unit stay were significantly longer in the MACE group compared to the non-MACE group. Accordingly, preoperative diastolic dysfunction (E/e' > 15) was related with postoperative MACE and MACE was related with 6-month survival after radical cystectomy. These results suggest that preoperative diastolic dysfunction can provide useful information on postoperative complications.

Structure-guided mutational evidence and postulates explaining how a glycohydrolase from Pyrococcus furiosus functions simultaneously as an amylase and as a 4-α-glucanotransferase.

Pyrococcus furiosus exoamylase-cum-4-α-glucanotransferase (4-α-GTase; PF0272; PfuAmyGT) is reported to both (i) act upon starch, and (ii) catalyze 'disproportionation' of maltooligosaccharides (with glucose as the smallest product). PfuAmyGT shares ∼65% sequence identity with a homo-dimeric Thermococcus litoralis 4-α-GTase, for which structures are available in complex with a non-hydrolysable analog of maltotetraose (acarbose) bound to one subunit and maltose (of unknown origin) bound to the other subunit. We structurally transposed the maltose onto the acarbose-bound subunit and discovered that the two molecules lie juxtaposed in what could be perfect 'acceptor' and 'donor' substrate-binding sites, respectively. We also discovered that there is a loop between the two sites which could use an available aspartate to excise a glucose from the donor, and an available tryptophan to transfer the glucose to the non-reducing end of the acceptor glucan. We derived a structure for PfuAmyGT through homology-based modeling, identified the potential donor site, acceptor site, glucan-transferring loop, and catalytically important residues, and mutated these to alanine to examine effect(s) upon activity. Mutation D362A abolished creation of shorter, or longer, maltooligosaccharides. Mutation W365A abolished creation of longer oligosaccharides. Mutation H366A had no effect on activity. We propose that D362 facilitates glucose excision, and that W365 facilitates its transfer, either (a) directly into solution (allowing PfuAmyGT to act as an exoamylase), or (b) by glycoside bond formation with an acceptor (allowing PfuAmyGT to act as a 4-α-glucanotransferase), depending upon whether the acceptor site is vacant or occupied in a reaction cycle.

A Legionella pneumophila amylase is essential for intracellular replication in human macrophages and amoebae.

Legionella pneumophila invades protozoa with an "accidental" ability to cause pneumonia upon transmission to humans. To support its nutrition during intracellular residence, L. pneumophila relies on host amino acids as the main source of carbon and energy to feed the TCA cycle. Despite the apparent lack of a requirement for glucose for L. pneumophila growth in vitro and intracellularly, the organism contains multiple amylases, which hydrolyze polysaccharides into glucose monomers. Here we describe one predicted putative amylase, LamB, which is uniquely present only in L. pneumophila and L. steigerwaltii among the ~60 species of Legionella. Our data show that LamB has a strong amylase activity, which is abolished upon substitutions of amino acids that are conserved in the catalytic pocket of amylases. Loss of LamB or expression of catalytically-inactive variants of LamB results in a severe growth defect of L. pneumophila in Acanthamoeba polyphaga and human monocytes-derived macrophages. Importantly, the lamB null mutant is severely attenuated in intra-pulmonary proliferation in the mouse model and is defective in dissemination to the liver and spleen. Our data show an essential role for LamB in intracellular replication of L. pneumophila in amoeba and human macrophages and in virulence in vivo.

Salivary Amylase: Digestion and Metabolic Syndrome.

Salivary amylase is a glucose-polymer cleavage enzyme that is produced by the salivary glands. It comprises a small portion of the total amylase excreted, which is mostly made by the pancreas. Amylases digest starch into smaller molecules, ultimately yielding maltose, which in turn is cleaved into two glucose molecules by maltase. Starch comprises a significant portion of the typical human diet for most nationalities. Given that salivary amylase is such a small portion of total amylase, it is unclear why it exists and whether it conveys an evolutionary advantage when ingesting starch. This review will consider the impact of salivary amylase on oral perception, nutrient signaling, anticipatory metabolic reflexes, blood sugar, and its clinical implications for preventing metabolic syndrome and obesity.

Clinical applications of amylase: Novel perspectives.

BACKGROUND: Amylase was the first enzyme to be characterized, and for the previous 200 years, its clinical role has been restricted to a diagnostic aid. Recent interface research has led to a substantial expansion of its role into novel, viable diagnostic, and therapeutic applications to cancer, infection, and wound healing. This review provides a concise "state-of-the-art" overview of the genetics, structure, distribution, and localization of amylase in humans. METHOD: A first-generation literature search was performed with the MeSH search string "Amylase AND (diagnost∗ OR therapeut$)" on OVIDSP and PUBMED platforms. A second-generation search was then performed by forward and backward referencing on Web of Knowledge™ and manual indexing, limited to the English Language. RESULTS: "State of the Art" in amylase genetics, structure, function distribution, localisation and detection of amylase in humans is provided. To the 4 classic patterns of hyperamylasemia (pancreatic, salivary, macroamylasemia, and combinations) a fifth, the localized targeting of amylase to specific foci of infection, is proposed. CONCLUSIONS: The implications are directed at novel therapeutic and diagnostic clinical applications of amylase such as the novel therapeutic drug classes capable of targeted delivery and "smart release" in areas of clinical need. Future directions of research in areas of high clinical benefit are reported.

Amy63, a novel type of marine bacterial multifunctional enzyme possessing amylase, agarase and carrageenase activities.

A multifunctional enzyme is one that performs multiple physiological functions, thus benefiting the organism. Characterization of multifunctional enzymes is important for researchers to understand how organisms adapt to different environmental challenges. In the present study, we report the discovery of a novel multifunctional enzyme Amy63 produced by marine bacterium Vibrio alginolyticus 63. Remarkably, Amy63 possesses amylase, agarase and carrageenase activities. Amy63 is a substrate promiscuous α-amylase, with the substrate priority order of starch, carrageenan and agar. Amy63 maintains considerable amylase, carrageenase and agarase activities and stabilities at wide temperature and pH ranges, and optimum activities are detected at temperature of 60 °C and pH of 6.0, respectively. Moreover, the heteroexpression of Amy63 dramatically enhances the ability of E. coli to degrade starch, carrageenan and agar. Motif searching shows three continuous glycosyl hydrolase 70 (GH70) family homologs existed in Amy63 encoding sequence. Combining serial deletions and phylogenetic analysis of Amy63, the GH70 homologs are proposed as the determinants of enzyme promiscuity. Notably, such enzymes exist in all kingdoms of life, thus providing an expanded perspective on studies of multifunctional enzymes. To our knowledge, this is the first report of an amylase having additional agarase and carrageenase activities.

[Studies on hibernation pivotal temperature of Whitmania pigra].

The biological characteristics, oxygen consumption, oxygen consumption rate, and activities of amylase, lipase and protease of Whitmania pigra at different temperature were studied by using direct observational method, the still water method and 3, 5-dinitrosalicylic acid colorimetry, right-nitrophenyl palmitate ester（ρ-NPP）colorimetry and folin-phenol method.The results revealed that with decreasing water temperature, the daily activity and the daily feeding ration were decreased. As the temperature was lowered to 4 ℃, the head and tail of Wh.pigra curved, showing a crescent-shape without feeding and daily activity. Oxygen consumption, oxygen consumption rate and digestive enzyme activities reduced along with temperature drops. The downward trend slowed below 10 ℃, began to stabilize below 4 ℃ and doesn't change with the decrease of temperature since then. During the 40 days treatment at 4 ℃, the changes of amylase were not significant, the lipase and protease activity decreased at the 20th day, and the lipase showed an slightly increase after the decrease and finally remained at a low level.In conclusions, the pivotal temperature of hibernation of Wh.pigra is 4 ℃ and the crescent shape can be considered as a symbol of hibernation.

Digestive enzyme activity of two stonefly species (Insecta, Plecoptera) and their feeding habits.

The digestive enzymes of two stoneflies species, Hemimelaena flaviventris and Isoperla morenica, were studied for the first time. These species are temporary water inhabitants and exhibit great feeding plasticity. Although they are traditionally referred to as predators, a previous study revealed that H. flaviventris incorporates some diatoms into its diet in addition to feeding usually on several prey, and I. morenica (in that study under the name of I. curtata) only feeds on animals occasionally. The enzymatic activities of digestive amylase, lipase, protease, trypsin and chymotrypsin were determined for each species at the same developmental stage. The results show that H. flaviventris has a greater digestive enzymatic pool and higher relative and absolute protease, lipase and trypsin activities than I. morenica. The latter has a relative higher amylase activity. As higher amylase activity is typical of phytophagous species and higher protease activity typical of carnivorous species; these results reveal that H. flaviventris is a more efficient zoophagous species than I. morenica. The ecological implications of these findings, including the higher secondary production of H. flaviventris in its habitat, are discussed.

Role of hormonal axis, growth hormone - IGF-1, in the therapeutic effect of ghrelin in the course of cerulein-induced acute pancreatitis.

Ghrelin is a ligand for growth hormone secretagogue receptor and stimulates release of growth hormone (GH). Recent studies have shown that treatment with ghrelin exhibits protective and therapeutic effect in the course of experimental pancreatitis. The aim of present study was to examine the role of GH and insulin-like growth factor-1 (IGF-1) in these effects. Acute pancreatitis was induced by cerulein. Study was performed on pituitary-intact hypophysectomized rats. Ghrelin was administered twice a day at the dose of 8 nmol/kg/dose. IGF-1 was given twice a day at the dose of 20 nmol/kg/dose. The severity of acute pancreatitis was assessed 0 h or 1, 2, 3, 5 and 10 days after the last dose of cerulein. Administration of cerulein led to the development of acute edematous pancreatitis. In pituitary-intact rats, treatment with ghrelin reduced biochemical indexes of the severity of acute pancreatitis and morphological signs of pancreatic damage, leading to faster regeneration of the pancreas reduction in serum concentration of pro-inflammatory interleukin-1ß and decrease in serum activity of amylase and lipase. These effects were accompanied with an improvement of pancreatic blood flow and an increase in pancreatic DNA synthesis. Hypophysectomy delayed the healing of the pancreas and abolished the therapeutic effect of ghrelin. In hypophysectomized rats with pancreatitis, treatment with IGF-1 exhibits therapeutic effect similar to that observed in ghrelin-treated rats with the intact pituitary. We conclude that therapeutic effect of ghrelin in cerulein-induced pancreatitis is indirect and depends on the release of GH and IGF-1.

Evolution of herbivory in a carnivorous clade of minnows (teleostei: cyprinidae): effects on gut size and digestive physiology.

We constructed a phylogeny for 10 minnow species (family Cyprinidae) previously revealed to be members of sister genera with different dietary affinities and used the phylogeny to examine whether the evolution of digestive tract size and physiology is correlated with the evolution of diet in these fishes. We studied a total of 11 taxa: four herbivorous species in the genus Campostoma and six largely carnivorous species in the genus Nocomis, including two populations of Nocomis leptocephalus, the carnivorous Chattahoochee River drainage population and the herbivorous Altamaha River drainage population. Thus, we were able to compare digestive tract size and physiology among sister genera (Campostoma and Nocomis) and among sister taxa (N. leptocephalus Chattahoochee and N. leptocephalus Altamaha) in dietary and phylogenetic contexts. The herbivorous taxa had longer digestive tracts and higher activity of the carbohydrases amylase and laminarinase in their guts, whereas the carnivorous species had higher chitinase activity. Phylogenetic independent-contrast analysis suggested that the evolution of amylase and chitinase activities was correlated with the evolution of diet in these species, whereas trypsin and lipase activities showed no pattern associated with diet or phylogenetic history. Concentrations of short-chain fatty acids were low in all taxa, indicating that these fishes rely largely on endogenous digestive mechanisms to subsist on their respective diets. Subtle differences in tooth shape were observed between species in the two genera. Overall, our results suggest that dietary specialization can be observed on the level of anatomy and physiology of the digestive tracts of fishes but that such differences are most appropriately viewed in comparisons of closely related species with different diets.

Parotid acinar cells transiently change to duct-like cells during epithelial-mesenchymal transition.

Hyposecretion of saliva and consequent dry mouth lead to severe caries and periodontal disease. Therapeutic radiation for head and neck cancer and sialadenitis result in atrophy and fibrosis of salivary glands, but the mechanism is not clear. As a model for dysfunction of salivary glands, we examined the change of gene expression patterns in primary cultured parotid acinar cells. The expression levels of acinar markers such as amylase and aquaporin-5 rapidly decreased during culture. At the same time, ductal markers began to be expressed although their expression was transient. In the late phase of culture, markers of epithelial-mesenchymal transition began to be expressed and increased. Inhibitor for Src or p38 MAP kinase suppressed these changes. These results suggest that parotid acinar cells transiently change to duct-like cells during epithelial-mesenchymal transition and that these changes are induced by signal transduction via Src-p38 MAP kinase pathway. There is a possibility that parotid acinar cells retain a plasticity of differentiation.

Human pancreatic digestive enzymes.

A primary function of the pancreas is to produce digestive enzymes that are delivered to the small intestine for the hydrolysis of complex nutrients. Much of our understanding of digestive enzymes comes from studies in animals. New technologies and the availability of the sequence of the human genome allow for a critical review of older reports and assumptions based on animal studies. This report updates our understanding of human pancreatic digestive enzymes with a focus on new insights into the biology of human proteases, lipases and amylases.

Effect of saliva composition on experimental root caries.

The aim of this study was to determine the effect of saliva composition on caries lesion development independently of the flow rate of unstimulated whole saliva (UWS) and other caries-related variables such as lesion progression time, oral hygiene level, and fluoride exposure. We hypothesized that this could be done by developing experimental root caries under carefully controlled conditions in situ in test subjects with UWS flow rates within a narrow window of normalcy. Fifteen female and 5 male subjects (66 +/- 6 years) were selected for the study according to their UWS flow rates between 0.2 and 0.4 ml/min. All subjects developed experimental root caries lesions during a 62-day period in which UWS as well as stimulated whole saliva (SWS) were repeatedly collected and analysed for flow rate, pH, buffer capacity, inorganic, and organic composition. Caries lesion development was determined by quantitative microradiography. The mean UWS flow rate was 0.30 +/- 0.05 ml/min. Significant negative correlations were obtained between UWS total phosphate concentration and mineral loss (DeltaZ; r(s) = -0.72, p < 0.001) and UWS total protein concentration and DeltaZ (r(s) = -0.70, p < 0.01). SWS and its constituents had only limited or no effect on DeltaZ. Qualitative UWS protein analysis (SDS-PAGE) revealed that subjects with low DeltaZ values had broader and more stained amylase bands than subjects with high DeltaZ values. These findings were confirmed quantitatively by HPLC. We conclude that, within a group of subjects with normal UWS flow rates, the UWS composition was more important for caries lesion development than the SWS composition. Furthermore, high UWS concentrations of phosphate, protein, and amylase were caries-protective.

Differential aggregation properties of secretory proteins that are stored in exocrine secretory granules of the pancreas and parotid glands.

Low-pH- and calcium-induced aggregation of regulated secretory proteins has been proposed to play a role in their retention and storage in secretory granules. However, this has not been tested for secretory proteins that are stored in the exocrine parotid secretory granules. Parotid granule matrix proteins were analyzed for aggregation in the presence or absence of calcium and in the pH range of 5.5 to 7.5. Amylase did not aggregate under these conditions, although <10% of parotid secretory protein (PSP) aggregated below pH 6.0. To test aggregation directly in isolated granules, rat parotid secretory granules were permeabilized with 0.1% saponin in the presence or absence of calcium and in the pH range of 5.0 to 8.4. In contrast to the low-pH-dependent retention of amylase in exocrine pancreatic granules, amylase was quantitatively released and most PSP was released from parotid granules under all conditions. Both proteins were completely released upon granule membrane solubilization. Thus neither amylase nor PSP show low-pH- or calcium-induced aggregation under physiological conditions in the exocrine parotid secretory granules.

Characterization of Aspergillus oryzae fermentation extract effects on the rumen fungus Neocallimastix frontalis, EB 188. Part 2. Carbon source utilization and effects on zoospore production.

The effect of a commercial Aspergillus oryzae fermentation extract on the utilization of carbon source and zoospore production by the rumen fungus Neocallimastix frontalis EB 188 was determined. In addition, the composition of a soluble extract prepared from the commercial product was analyzed. This extract was added to N. frontalis EB 188 cultures grown on a variety of substrates and periodically assayed for protein, enzymes, zoospore production, and carbon source utilization. The powdered product contained 93% dry matter, more than 3,000 A. oryzaespores per gram, and did not contain strong buffers or high concentrations of salt. Measurable concentrations of DNA, protein, carbohydrate and several enzymes including cellulase and amylase were also found. Soluble extract increased fungal physiology and treated cultures produced significantly higher levels of supernatant protein and enzymes including amylase, cellulase and beta-glucosidase. The fungal response depended on culture carbon source. However, culture zoospore production was increased regardless of substrate provided. Culture utilization of glucose was more rapid in treated cultures, yet high levels of the extract greatly inhibited glucose utilization.

Both thermal and non-thermal stress protect against caerulein induced pancreatitis and prevent trypsinogen activation in the pancreas.

BACKGROUND AND AIM: Recent studies have indicated that prior thermal stress causes upregulation of heat shock protein 70 (HSP70) expression in the pancreas and protects against secretagogue induced pancreatitis. The mechanisms responsible for the protective effect are not known. Similarly, the effects of prior non-thermal stress on HSP70 expression and pancreatitis are not known. The current studies were designed to specifically address these issues. METHODS: In the current studies pancreatitis was induced by administration of a supramaximally stimulating dose of caerulein 12 hours after thermal stress and 24 hours after non-thermal (that is, beta adrenergic stimulation) stress. RESULTS: Both thermal and non-thermal stresses caused pancreatic HSP70 levels to rise and resulted in increased expression of HSP70 in acinar cells. Both forms of stresses protected against caerulein induced pancreatitis and prevented the early intrapancreatic activation of trypsinogen which occurs in this model of pancreatitis. CONCLUSIONS: These results suggest that both thermal and non-thermal stresses protect against pancreatitis by preventing intrapancreatic digestive enzyme activation and that HSP70 may mediate this protective effect.

Indicadores de actividad amilasa en la enfermedad parotídea. Parotiditis crónica recurrente infantil / Amylase activity markers for parotid disease: infant recurrent chronic parotiditis

No disponible