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At least 523 records · Page 29Linked to original sources
PubMed2005

Novel actinobacteria from marine sponges.

Actinobacteria exclusively within the sub-class Acidimicrobidae were shown by 16S rDNA community analysis to be major components of the bacterial community associated with two sponge species in the genus Xestospongia. Four groups of Actinobacteria were identified in Xestospongia spp., with three of these four groups being found in both Xestospongia muta from Key Largo, Florida and Xestospongia testudinaria from Manado, Indonesia. This suggests that these groups are true symbionts in these sponges and may play a common role in both the Pacific and Atlantic sponge species. The fourth group was found only in X. testudinaria and was a novel assemblage distantly related to any previously sequenced actinobacterial clones. The only actinobacteria that were obtained in initial culturing attempts were Gordonia, Micrococcus and Brachybacterium spp., none of which were represented in the clone libraries. The closest cultured actinobacteria to all the Acidimicrobidae clones from Xestospongia spp. are 'Microthrix parvicella' and Acidimicrobium spp. Xestospongia spp. can now be targeted as source material from which to culture novel Acidimicrobidae to investigate their potential as producers of bioactive compounds. Isolation of sponge-associated Acidimicrobidae will also make it possible to elucidate their role as sponge symbionts.

Actinobacteria↗
PubMed2004

Functional foods, herbs and nutraceuticals: towards biochemical mechanisms of healthy aging.

Aging is associated with mitochondrial dysfunctions, which trigger membrane leakage, release of reactive species from oxygen and nitrogen and subsequent induction of peroxidative reactions that result in biomolecules' damaging and releasing of metals with amplification of free radicals discharge. Free radicals induce neuronal cell death increasing tissue loss, which could be associated with memory detriment. These pathological events are involved in cardiovascular, neurodegenerative and carcinogenic processes. Dietary bioactive compounds from different functional foods, herbs and nutraceuticals (ginseng, ginkgo, nuts, grains, tomato, soy phytoestrogens, curcumin, melatonin, polyphenols, antioxidant vitamins, carnitine, carnosine, ubiquinone, etc.) can ameliorate or even prevent diseases. Protection from chronic diseases of aging involves antioxidant activities, mitochondrial stabilizing functions, metal chelating activities, inhibition of apoptosis of vital cells, and induction of cancer cell apoptosis. Functional foods and nutraceuticals constitute a great promise to improve health and prevent aging-related chronic diseases.

Aging↗
PubMed2006

Methionine-enkephalin modulated regulation of oxidant/antioxidant status in liver of CBA mice.

Reactive oxygen species (ROS) are formed by all aerobic organisms, and are involved in the numerous physiological and pathophysiological processes. Opioid peptides belong to a class of bioactive compounds of great interest because of their opiate-like activity. We determined the influence of methionine-enkephalin (MENK) on age-associated oxidant/antioxidant status in liver of CBA mice. Lipid peroxidation (LPO), total superoxide dismutase (tSOD), catalase (CAT), and glutathione peroxidase (Gpx) activities of 1, 4, 10 and 18 months old male and female control and MENK treated (10 mg/kg bw) CBA mice were determined. MENK showed gender-related effect on both oxidant/antioxidant parameters. It stimulated LPO in males, but suppressed in females. CAT and Gpx activities were lowered upon MENK exposure in males, but in females the activities were modulated by MENK. The relative mRNA levels for the antioxidant enzymes CuZnSOD, MnSOD, CAT and Gpx-1 were determined by reverse transcriptase polymerase chain reaction (RT-PCR) in groups where differences in activities between control and treated samples were observed. Changes of mRNA level in MENK treated groups showed that transcriptional regulation is both gender- and age-related. Comparison of enzyme activities and mRNA levels in control and MENK treated groups showed that, in some cases parallel changes occurred, while in other cases nonparallel changes were found. These results suggest that transcriptional changes are in accordance with enzyme activities in some cases, while in other cases posttranscriptional regulation of antioxidant enzymes may exist.

Aging↗
PubMed2006

Effect of bitter gourd and spent turmeric on constituents of glycosaminoglycans in different tissues in streptozotocin induced diabetic rats.

Diet is now one of the well established means in the management of diabetes. Bitter gourd and spent turmeric at 10% level were tested for their efficacy on glycosaminoglycan metabolism in various tissues viz., liver, spleen, lungs, heart and testis in control, diabetic and treated rats. The glycosaminoglycans (GAGs) were isolated from defatted and dried tissues. The contents of sulfated GAGs decreased in all the tissues and the decrease was more prominent in heart and testis. In the isolated GAGs, contents of total sugar, amino sugar, uronic acid and sulfate were studied. Decrease in total sugar content was maximum in testis. Amino sugar content decreased considerably in testis (38%) and lungs (15%). The content of uronic acid also decreased in testis (33%) besides heart (29%) and liver (25%). Sulfate groups in GAGs perform pivotal functions in many biological events and decrease in sulfate content was significant in heart (40%), testis (37%) and liver (37%). GAGs profile on the cellulose acetate electrophoresis revealed that heparan sulfate (HS), hyaluronic acid (HA) and chondroitin sulfate/dermatan sulfate (CS/DS) were present in liver, spleen and lungs. HS, CS were present in heart, DS/CS was observed in testis. The observed beneficial effects in GAGs metabolism during diabetes may be due to the presence of high amounts of dietary fibres present in bitter gourd and spent turmeric, besides, possible presence of bioactive compounds in one or both of them.

Amino Sugars↗
PubMed2004

Antagonism against Rhizoctonia solani and fungitoxic metabolite production by some Penicillium isolates.

A number of Penicillium isolates were recovered in association to Rhizoctonia solani strains pathogenic on tobacco and from soil on plates pre-colonized by the pathogen itself. Their antagonism toward R. solani AG-2-1 was evaluated in dual cultures in vitro. Inhibition of growth was evident to some extent in most pairings, while hyphal interactions referable to mycoparasitic relationships were not observed. However, the occurrence of plasmolysis and/or vacuolisation and the induction of monilioid cells were indicative of the release of bioactive compounds. Therefore, production of fungitoxic metabolites was tested by adding concentrated culture filtrates of each Penicillium isolate to the growth medium of R. solani. Complete and lasting inhibition was incited by culture filtrates of some isolates belonging to P. brevicompactum, P. expansum, and P. pinophilum. Three purified compounds, respectively mycophenolic acid, patulin and 3-O-methylfunicone, which were extracted from culture filtrates, were able to inhibit R. solani in vitro. Their production was also detected in dual cultures of the same Penicillium strains with R. solani prepared in sterilized soil and when the Penicillium strains were cultured directly on R. solani mycelium harvested from liquid cultures. The possible role of such metabolites in antagonism of the above-mentioned Penicillium species against R. solani is discussed.

Antibiosis↗
PubMed2006

4-Hydroxyacetophenone-induced choleresis in rats is mediated by the Mrp2-dependent biliary secretion of its glucuronide conjugate.

PURPOSE: The present study examined the underlying mechanism by which 4-hydroxyacetophenone (4-HA), a bioactive compound found in several medicinal herbs, exerts its potent stimulatory effects on hepatic bile secretion. METHODS: Bile flow, and biliary excretion of 4-HA, its metabolites, and inorganic electrolytes was examined in both normal Wistar rats and in TR(-) Wistar rats that have a congenital defect in the multidrug resistance-associated protein-2, Mrp2/Abcc2. The effects of 4-HA were also examined in animals treated with buthionine sulfoximine to decrease hepatic glutathione (GSH) levels. RESULTS: In normal rats, 4-HA dramatically increased bile flow rate, whereas it failed to exert a choleretic effect in TR(-) rats. This choleresis was not explained by increased biliary output of Na(+), K(+), Cl(-) or HCO(3) (-), or by increased biliary GSH excretion. Depletion of hepatic GSH with buthionine sulfoximine had no effect on the 4-HA-induced choleresis. HPLC analysis revealed that a single major compound was present in bile, namely.4-hydroxyacetophenone-4-O-beta-glucuronide, and that the parent compound was not detected in bile. Biliary excretion of the glucuronide was directly correlated with the increases in bile flow. In contrast to normal rats, this 4-HA metabolite was not present in bile of TR(-) rats. CONCLUSIONS: These results demonstrate that the major biliary metabolite of 4-HA in rats is the 4-O-beta-glucuronide, a compound that is secreted into bile at high concentrations, and may thus account in large part for the choleretic effects of 4-HA. Transport of this metabolite across the canalicular membrane into bile requires expression of the Mrp2 transport protein.

Acetophenones↗
PubMed2026

Coating materials enhance urochordate primary cell culture adherence.

Marine invertebrate cell cultures are a potential source for diverse biotechnological applications, given the wide range of bioactive compounds they synthesize and accumulate. Yet, the number of established marine invertebrate cell culture systems remains limited compared with those of insects and vertebrates, particularly with respect to adherent cell cultures. Here we studied the in vitro adherence of circulating blood cells from the colonial ascidian Botryllus schlosseri. Two experimental approaches were employed, seeding blood cells either alone (setup 1) or in combination with tissue fragments (setup 2), using three basal media (DMEM, DMEM/F-12, RPMI) on culture plates coated with either Poly-L/D-lysine, gelatin, collagen, or laminin. Each experiment lasted for up to 3 d. Setup 1 results reveal that Botryllus cells remain viable and can adhere to coated surfaces in all tested media. Collagen- and laminin-coated plates supported longer-term cultures, whereas Poly-D (or L)-lysine coatings were more suitable for short-term studies. Among the basal media, RPMI and DMEM/F12 most effectively supported cell attachment. Setup 2 plates consistently showed higher cell adherence compared to setup 1, suggesting that tissue-derived factors may enhance attachment. Overall, circulating Botryllus cells demonstrate the capacity for substrate adhesion in vitro, offering a foundation for the development of adherent cell cultures.

Animals↗
PubMed1999

Bioassay development: the implications of cardiac myocyte motility in vitro.

Cardiac myocytes cultured over microfabricated extracellular recording devices can be used to assay bioactive compounds. However, electrophysiological signals recorded from these devices vary in amplitude with time. Theoretically, changes in signal amplitude arise from myocytes being moved over recording sites by cocultured fibroblasts. To test this, neonatal rat cardiac myocytes were cultured at high densities and low densities on fibronectin-coated glass. After 36.5 h, myocytes were identified by their rhythmic contractions and then time-lapse-recorded for 3.5 h. Length, width, and angle of orientation was then determined every 30 min for five cells in low density and five cells in high-density culture. Low-density cells had mean lengths of 65.3 microm and widths of 35.1 microm, whereas cells in high-density culture had greater mean lengths of 74.2 microm and lower mean widths of 24.3 microm. Length, width, and angle of orientation of cells in low- and high-density culture changed by 4.1%, 11.8%, and 2.7 degrees, and 6.4%, 10%, and 4.6 degrees, respectively, every half hour. We found no evidence of myocyte-fibroblast interactions influencing cell position or shape in low density, but in high density, we found evidence that fibroblast-myocyte interactions could transiently influence cell shape. We conclude that fibroblast-independent changes in cell shape are largely responsible for the changes in signal amplitude recorded from cardiac myocytes cultured on microfabricated extracellular recording devices. However, there is some evidence that myocyte-fibroblast interactions may augment this process in high-density culture. The implications of these findings for bioassay development are discussed.

Animals↗
PubMed2003

Role of dietary calcium and dairy products in modulating adiposity.

Dietary calcium plays a pivotal role in the regulation of energy metabolism. High-calcium diets attenuate adipocyte lipid accretion and weight gain during overconsumption of an energy-dense diet and increase lipolysis and preserve thermogenesis during caloric restriction, thereby markedly accelerating weight loss. Our studies of the agouti gene demonstrate a key role for intracellular Ca2+ in regulating adipocyte lipid metabolism and TG storage. Increased intracellular Ca2+ resulting in stimulation of lipogenic gene expression, and lipogenesis and suppression of lipolysis resulting in adipocyte lipid filling and increased adiposity. Moreover, we recently demonstrated that the increased calcitriol produced in response to low-calcium diets stimulates adipocyte Ca2+ influx and, consequently, promotes adiposity. Accordingly, suppressing calcitriol levels by increasing dietary calcium is an attractive target for obesity intervention. In support of this concept, transgenic mice expressing the agouti gene specifically in adipocytes (a human-like pattern) respond to low-calcium diets with accelerated weight gain and fat accretion, whereas high-calcium diets markedly inhibit lipogenesis, accelerate lipolysis, increase thermogenesis, and suppress fat accretion and weight gain in animals maintained at identical caloric intakes. Further, low-calcium diets impede body fat loss, whereas high-calcium diets markedly accelerate fat loss in transgenic mice subjected to caloric restriction. Dairy sources of calcium exert markedly greater effects in attenuating weight and fat gain and accelerating fat loss. This augmented effect of dairy products is likely due to additional bioactive compounds in dairy that act synergistically with calcium to attenuate adiposity. These concepts are confirmed by both epidemiological and clinical data, which demonstrate that increasing dietary calcium results in significant reductions in adipose tissue mass in obese humans in the absence of caloric restriction and markedly accelerates the weight and body fat loss secondary to caloric restriction, whereas dairy products exert significantly greater effects. These data indicate an important role for dairy products in both the prevention and treatment of obesity.

Adipose Tissue↗
PubMed2006

Natural neo acids and neo alkanes: their analogs and derivatives.

This review presents more than 260 naturally occurring (as well as 47 synthesized) neo fatty (carboxylic) acids, neo alkanes, and their analogs and derivatives, isolated and identified from plants, algae, fungi, marine invertebrates, and microorganisms, that demonstrate different biological activities. These natural metabolites are good prospects for future chemical preparations as antioxidants, and also as anticancer, antimicrobial, and antibacterial agents. Described also are some synthetic bioactive compounds containing a tertiary butyl group(s) that have shown high anticancer, antifungal, and other activities. Applications of some neo fatty (carboxylic) acid derivatives in cosmetic, agronomic, and pharmaceutical industries also are considered. This is the first review to consider naturally occurring neo fatty (carboxylic) acids, neo alkanes, and other metabolites containing a tertiary butyl group(s) [or tert-butyl unit(s)].

Alkanes↗
PubMed2026

Microalgae-Mediated Synthesis of Gold Nanoparticles from Indonesian Chlorella vulgaris InaCC M205 with Potential Anticancer Properties for Biomedical Application.

Sustainable nanomaterial synthesis has emerged as a critical strategy to reduce the environmental burden associated with conventional chemical synthesis method. Microalgae-derived biomolecules offer a promising platform for the green production of metal nanoparticles due to their rich bioactive compounds capable of acting as natural reducing and stabilizing agents. Here, we report the eco-friendly synthesis of gold nanoparticles (AuNPs) using extract of Indonesian microalga Chlorella vulgaris extract. To optimize the synthesis process, the effects of precursor-to-extract ratio, temperature, and incubation time were evaluated. Optimal synthesis of C5-AuNPs was obtained at 37 °C for 20 h with precursor to extract ratio of 6:4, resulting in moderately stable C5-AuNPs characterized by a surface plasmon resonance (SPR) peak at 541 nm. Furthermore, Fourier-transmission infra-red (FT-IR) analysis revealed the involvement of functional groups of C. vulgaris extract in the interaction with Au+ during the production of C5-AuNPs. Transmission electron microscopy (TEM) demonstrated the formation of uniformly spherical nanoparticles with an average diameter of approximately 8.8 nm. Biological evaluation showed that the synthesized C5-AuNPs exerted pronounced dose-dependent cytotoxicity against MCF-7 breast cancer cells with an IC50 threshold of 21.17 ppm, while no toxicity appears in normal HEK293 cells. Mechanistically, the C5-AuNPs induced early apoptosis and inhibit cell-cycle progression at the stage of G0/G1. Collectively, these findings demonstrate that C. vulgaris-mediated AuNPs represent a promising preliminary in vitro findings for cancer therapy candidate.

Gold↗
PubMed2006

Are the olive oil and other dietary lipids related to cancer? Experimental evidence.

There is a wealth of evidence supporting the relationship between dietary lipids and cancer, particularly those of the breast, colon and rectum and prostate. The main support comes from the international correlational studies and, especially, from experimental ones. The evidence from human analytical studies is less consistent because of several conflicting findings, probably due to methodological issues. Experimentally, it has been clearly demonstrated that quantity and type of dietary lipids as well as the particular critical phases of the carcinogenesis in which they act, are the essential factors in this relationship. Thus, whereas high dietary intake of n-6 polyunsaturated fatty acids (PUFA), primarily LA, and saturated fat has tumor-enhancing effects, long chain n-3 PUFA, CLA and GLA have inhibitory effects. Monounsaturated fatty acids (MUFA), mainly OA, present in high quantities in olive oil, seem to be protective although some inconsistent results have been reported. Bioactive compounds of virgin olive oil may also account for the protective effect of this oil, which is the main source of fat in the Mediterranean diet. Experimental studies have also provided evidence of several putative mechanisms of action of dietary lipids on cancer. Lipids can influence the hormonal status, modify cell membranes structure and function, cell signalling transduction pathways and gene expression, and modulate the function of the immune system. Although further studies are needed to evaluate and verify these mechanisms in humans, based on the multiple ways dietary lipids can act, they may have an important influence on tumorigenesis.

Animals↗
PubMed1991

The direct measurement of protein kinase C (PKC) activity in isolated membranes using a selective peptide substrate.

A protein kinase C (PKC)-selective peptide substrate was used to develop a method for measuring PKC activity directly and quantitatively in isolated cell membranes without prior detergent extraction and reconstitution of the enzyme with phosphatidylserine and TPA in the presence of excess Ca2+. This simple and rapid method can reliably measure changes in membrane-associated PKC activity induced by various bioactive compounds such as hormones and growth factors. Also, this method, which measures PKC activity in its native membrane-associated state, has the advantage of being able to distinguish between active and inactive PKC associated with cell membranes.

Amino Acid Sequence↗
PubMed1986

Transbilayer reorientation of platelet-activating factor in the erythrocyte membrane.

Platelet-activating factor (PAF) is a phospholipid, intermediate in its structure between diacyl- and lysophospholipids. The reorientation of this highly bioactive compound to the inner membrane layer of human erythrocytes after its primary incorporation into the outer membrane layer has been studied. Reorientation was shown to be a slow process with an initial rate of only 0.012 h-1. It does not depend on energy supply. From the steady-state distribution of PAF between inner and outer membrane layers, after very long incubation times (40-50 h), a preference of PAF for the outer membrane layer analogous to that of endogenous lecithin is derived. Our data indicate that the process of simple transbilayer reorientation of PAF is probably too slow to account for very fast transmembrane signal transmission or for the fast uptake and metabolism observed in certain cell types.

Acylation↗
PubMed1994

Isolation of serotonin from the accessory salivary glands of the marine snail Nucella lapillus.

We report here the presence of a bioactive compound in the secretion of the accessory salivary glands (ASGs) of Nucella lapillus. We have purified the compound using HPLC and identified it as serotonin by mass spectrometry, UV spectroscopy, HPLC and capillary electrophoresis. Serotonin was not found in the secretions of the acinous salivary glands or the hypobranchial gland. The amount of serotonin in the secretion of the ASGs does not show seasonal or regional variation.

Animals↗
PubMed1995

Enkephalin immunoreactivity in the paraneurons of the tiger salamander (Ambystoma tigrinum) tongue.

Immunohistochemical tests have demonstrated the presence of leu-5-enkephalin and other bioactive compounds (serotonin and neuron-specific enolase) in the basal cells of lingual taste buds in Ambystoma tigrinum; there was also a weak reaction for met-5-enkephalin. Similar reactions were obtained from particular cells dispersed within the lingual epithelium, which are provisionally identified as Merkel cells.

Ambystoma↗
PubMed1990

Lipid metabolism and signal transduction in endothelial cells.

Endothelial cells have the capacity to metabolize several important lipids; this includes the ability to store and then metabolize arachidonate, as well as the capacity to synthesize platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine). Arachidonate is predominantly metabolized via cyclooxygenase to PGI2 although the spectrum of prostaglandins may vary depending upon the source of the endothelial cell. Biosynthesis of eicosanoids and PAF are likely to be an important physiologic function of the endothelial cell as these potent lipids appear to have a role in maintaining vascular tone and mediating interactions of the endothelium with circulating inflammatory cells. In addition to production of eicosanoids and PAF, endothelial cells metabolize exogenous arachidonate and arachidonate metabolites and other fatty acids such as linoleate to bioactive compounds (HODEs). There is also evidence that small amounts of arachidonate are metabolized via a lipoxygenase. The physiologic significance of these minor lipid pathways is not known at this time. Production of eicosanoids and PAF is not a constitutive function of the endothelial cell. Lipid biosynthesis by endothelial cells is one component of the early activation response that occurs in response to stimulation with pro-inflammatory and vasoactive hormones or to pathologic agents such as oxidants and bacterial toxins. A central mechanism for activation of the relevant pathways is a rise in cellular calcium concentrations that can be mediated by hormone-receptor-binding or by direct permeabilization of the cell membrane to calcium (Fig. 3). Regulatory mechanisms distal to the calcium signal are unknown, but current evidence suggests that calcium directly or indirectly activates phospholipases that release arachidonate from phospholipids and hydrolyze a specific phospholipid to the immediate precursor of PAF. There is evidence that protein kinase C may, in part, regulate this process, but the role of other potential regulatory components, such as other protein kinases or G-proteins is not known. As noted above, the most direct mechanism for initiation of PAF biosynthesis and arachidonate release would be activation of a phospholipase A2 as shown in Fig. 3. Activation of other phospholipases (e.g. phospholipase C) may contribute to the total amount of arachidonate released, although the magnitude of that contribution is not yet known. In addition to generation of PAF and eicosanoids, activation of endothelial cell phospholipases generates second messengers that are important in intracellular signaling (Fig. 4). Activation of phospholipase C, in response to hormonal stimulation, generates diacylglycerol and inositol phosphates from phosphatidylinositol. Each of these is a potent intracellular second messenger.(ABSTRACT TRUNCATED AT 400 WORDS)

Arachidonic Acid↗
PubMed1994

Anatomical and functional imaging of neurons using 2-photon laser scanning microscopy.

Light scattering by brain tissue and phototoxicity are major obstacles to the use of high-resolution optical imaging and photo-activation ('uncaging') of bioactive compounds from inactive ('caged') precursors in intact and semi-intact nervous systems. Optical methods based on 2-photon excitation promise to reduce these obstacles (Denk, 1994; Denk et al., 1990, 1994). Here we show a range of imaging modes based on 2-photon laser scanning microscopy (TPLSM) as applicable to problems in neuroscience. Fluorescence images were taken of neurons labeled with ion-sensitive and voltage-sensitive dyes in invertebrate ganglia, mammalian brain slices, and from the intact mammalian brain. Scanning photochemical images with whole-cell current detection (Denk, 1994) show how the distribution of neurotransmitter receptors on the surface of specific cells can be mapped. All images show strong optical sectioning and usable images can be obtained at depths greater than 100 microns below the surface of the preparation.

Animals↗