Antimicrobial peptides (AMPs) are crucial effectors of the innate immune system. They provide the first line of defense against a variety of pathogens. AMPs display synergistic effects with ...conventional antibiotics, and thus present the potential for combined therapies. Insects are extremely resistant to bacterial infections. Insect AMPs are cationic and comprise less than 100 amino acids. These insect peptides exhibit an antimicrobial effect by disrupting the microbial membrane and do not easily allow microbes to develop drug resistance. Currently, membrane mechanisms underlying the antimicrobial effects of AMPs are proposed by different modes: the barrel-stave mode, toroidal-pore, carpet, and disordered toroidal-pore are the typical modes. Positive charge quantity, hydrophobic property and the secondary structure of the peptide are important for the antibacterial activity of AMPs. At present, several structural families of AMPs from insects are known (defensins, cecropins, drosocins, attacins, diptericins, ponericins, metchnikowins, and melittin), but new AMPs are frequently discovered. We reviewed the biological effects of the major insect AMPs. This review will provide further information that facilitates the study of insect AMPs and shed some light on novel microbicides.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•This study analyzed how PAs were involved in AMF-enhanced drought tolerance of plants.•AM trifoliate orange had higher Put and Cad and lower Spd and Spm under drought.•Mycorrhizal plants had higher ...activity of PA catabolic enzymes and Put synthetase.•AM plants showed overexpression of PtSPMS, PtPAO, PtSOD, and PtCAT1 under DS.•AM plants represented down-regulated expression of PtCuAO under DS.
Arbuscular mycorrhizas enhance the drought tolerance of host plants through several underlying mechanisms. Polyamines (PAs) are known to protect plant cells from the damages of drought by enhancing the antioxidant defense system, restricting ethylene synthesis, maintaining cell pH and ion homeostasis, preventing chlorophyll loss, and so on; concomitantly, the mechanism through which arbuscular mycorrhizal (AM) fungi modulate PA metabolism to enhance drought tolerance of plants remains unclear. A pot experiment was conducted to assess how an AM fungus, Funneliformis mosseae, affects root PA homeostasis, activities and gene expressions of PA-related synthesizing and degrading enzymes, hydrogen peroxide (H2O2, a PA metabolite) production, and antioxidant enzyme gene expressions in trifoliate orange (Poncirus trifoliata) exposed to drought stress (DS). AM seedlings showed higher growth traits, leaf water potential, two plasma membrane intrinsic protein aquaporin gene expressions, and chlorophyll concentrations than non-AM seedlings under well-watered (WW) and DS conditions. Mycorrhizal treatment induced higher putrescine and cadaverine but lower spermidine and spermine concentrations, with higher activity of PA catabolic enzymes (copper-containing diamine oxidase, CuAO; polyamine oxidase, PAO) and putrescine synthases (ornithine decarboxylaseby; arginine decarboxylase, ADC). Mycorrhizas up-regulated the expression of the spermine synthase gene, PtSPMS, under DS, and down-regulated the transcript levels of PA catabolic enzyme genes (PtCuAO1, PtCuAO2, PtCuAO6, and PtCuAO8) and PA synthase genes (PtADC1 and PtADC2) under DS. PtPAO1, PtPAO2, and PtPAO3 had higher expression levels in AMF-inoculated seedlings, as compared to non-AMF-inoculated seedlings, under DS, triggering reactive oxygen species-related signalling for stress responsiveness through low H2O2 levels by up-regulating the expression of PtMn-SOD, PtCu/Zn-SOD, and PtCAT1. This study demonstrated that mycorrhizas have the capacity to modulate PA metabolism to enhance the drought tolerance of plants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Therapeutic application of newly developed oximes is limited due to their adverse effects on different tissues. Within this article, it has been investigated which morphological changes could be ...observed in Wistar rats after the treatment with increasing doses of selected acetyl cholinesterase reactivators - asoxime, obidoxime, K027, K048, and K075. Subsequently, heart, diaphragm and musculus popliteus were obtained for pathohistological and semiquantitative analysis 24 hrs and 7 days after im administration of a single dose of 0.1 LD
, 0.5 LD
, and 1.0 LD
of each oxime. Different muscle damage score was based on an estimation scale from 0 (no damage) to 5 (strong damage). In rats treated with 0.1 LD
of each oxime, muscle fibres did not show any change. The intensive degeneration was found in all muscles after treatment with 0.5 LD
of asoxime and obidoxime, respectively. Acute toxic muscle injury was developed within 7 days following treatment with 0.5 LD
and 1.0 LD
of each oxime, with the highest values in K048 and K075 group (P < 0.001 vs. control and asoxime), respectively. The early muscle alterations observed in our study seem to contribute to the pathogenesis of the oxime-induced toxic muscle injury, which probably manifests as necrosis and/or inflammation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A feature of arbuscular mycorrhiza is enhanced drought tolerance of host plants, although it is unclear whether host H
-ATPase activity and gene expression are involved in the physiological process. ...The present study aimed to investigate the effects of an arbuscular mycorrhizal fungus (AMF),
, on H
-ATPase activity, and gene expression of trifoliate orange (
) seedlings subjected to well-watered (WW) and drought stress (DS), together with the changes in leaf gas exchange, root morphology, soil pH value, and ammonium content. Soil drought treatment dramatically increased H
-ATPase activity of leaf and root, and AMF inoculation further strengthened the increased effect. A plasma membrane (PM) H
-ATPase gene of trifoliate orange, PtAHA2 (MW239123), was cloned. The
expression was induced by mycorrhization in leaves and roots and also up-regulated by drought treatment in leaves of AMF-inoculated seedlings and in roots of AMF- and non-AMF-inoculated seedlings. And, the induced expression of
under mycorrhization was more prominent under DS than under WW. Mycorrhizal plants also showed greater photosynthetic rate, stomatal conductance, intercellular CO
concentration, and transpiration rate and better root volume and diameter than non-mycorrhizal plants under DS. AMF inoculation significantly increased leaf and root ammonium content, especially under DS, whereas it dramatically reduced soil pH value. In addition, H
-ATPase activity was significantly positively correlated with ammonium contents in leaves and roots, and root H
-ATPase activity was significantly negatively correlated with soil pH value. Our results concluded that AMF stimulated H
-ATPase activity and
gene expression in response to DS, which resulted in great nutrient (e.g., ammonium) uptake and root growth, as well as low soil pH microenvironment.
Vascular cognitive impairment (VCI) is the second most common cause of cognitive deficit after Alzheimer's disease. Since VCI patients represent an important target population for prevention, an ...ongoing effort has been made to elucidate the pathogenesis of this disorder. In this review, we summarize the information from animal models on the molecular changes that occur in the brain during a cerebral vascular insult and ultimately lead to cognitive deficits in VCI. Animal models cannot effectively represent the complex clinical picture of VCI in humans. Nonetheless, they allow some understanding of the important molecular mechanisms leading to cognitive deficits. VCI may be caused by various mechanisms and metabolic pathways. The pathological mechanisms, in terms of cognitive deficits, may span from oxidative stress to vascular clearance of toxic waste products (such as amyloid beta) and from neuroinflammation to impaired function of microglia, astrocytes, pericytes, and endothelial cells. Impaired production of elements of the immune response, such as cytokines, and vascular factors, such as insulin-like growth factor 1 (IGF-1), may also affect cognitive functions. No single event could be seen as being the unique cause of cognitive deficits in VCI. These events are interconnected, and may produce cascade effects resulting in cognitive impairment.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Arbuscular mycorrhizal fungi (AMF) reduce disease incidence of host plants through the competition of carbon sources and direct inhibition of pathogens, as well as through induction of biochemical ...and molecular responses. However, it is not known whether AMF enhance the resistance to
Phytophthora parasitica-
induced root rot in citrus and what the underlying mechanisms are. This study was carried out to analyze roles of
Funneliformis mosseae
(a mycorrhizal fungus) in plant defence responses of
Poncirus trifoliata
infected by
P. parasitica
. A week after the pathogen infection, mycorrhizal seedlings possessed higher expression of root mitogen-activated protein kinase 3 (
PtMAPK3
) regardless of
P. parasitica
infection.
F
.
mosseae
induced higher root salicylic acid (SA) concentrations, accompanied with up-regulation of SA synthesis genes (
PtPAL1
and
PtEPS1
), regardless of being infected with
P. parasitica
or not. Jasmonic acid (JA) synthesis genes were down-regulated by mycorrhization in the absence of
P. parasitica
and up-regulated (except for
PtAOC
) by mycorrhization under
P
.
parasitica
infection. Moreover,
F
.
mosseae
stimulated higher expression of pathogenesis-related protein gene 1 (
PtPR1
),
PtPR4
, and
PtPR5
, especially under
P
.
parasitica
infection.
F
.
mosseae
inoculation increased levels of root lignin, calmodulin, and total soluble phenol and activities of root chitinase, phenylalanine ammonialyase, and β-1,3-glucanase, and decreased concentrations of root nitric oxide with or without
P. parasitica
infection. These results implied that
F
.
mosseae
elicited MAPKs cascades as well as SA- and calmodulin-mediated signal pathways to activate disease-defence genes, proteins, and compounds to early-warn
P
.
parasitica
infection for enhancing tolerance of root rot in trifoliate orange.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In plants, there is a complex and multilevel network of the antioxidative system (AOS) operating to counteract harmful reactive species (RS), the foremost important of which are reactive oxygen ...species (ROS), and maintain homeostasis within the cell. Specific AOSs for plant cells are, first and foremost, enzymes of the glutathione-ascorbate cycle (Asc-GSH), followed by phenolic compounds and lipophilic antioxidants like carotenoids and tocopherols. Evidence that plant cells have excellent antioxidative defense systems is their ability to survive at H
O
concentrations incompatible with animal cell life. For the survival of stressed plants, it is of particular importance that AOS cooperate and participate in redox reactions, therefore, providing better protection and regeneration of the active reduced forms. Considering that plants abound in antioxidant compounds, and humans are not predisposed to synthesize the majority of them, new fields of research have emerged. Antioxidant potential of plant compounds has been exploited for anti-aging formulations preparation, food fortification and preservation but also in designing new therapies for diseases with oxidative stress implicated in etiology.
Tea plants grown in acidic soils are strongly dependent on arbuscular mycorrhizas, whereas it is not clear whether soil arbuscular mycorrhizal fungi (AMF) improve plant growth, root development, and ...nutrient absorption in tea plants. A potted study was conducted to determine the effects of Claroideoglomus etunicatum, Diversispora spurca, D. versiformis and a mixture of the three AMF species on plant growth, root morphology, root-hair growth, and leaf nutrient status in Camellia sinensis cv. Fuding Dabaicha in Jingzhou, China. After 12 weeks of AMF inoculation, root mycorrhizal colonization ranged from 15.12% to 40.23%. AMF inoculation heavily increased plant height, shoot and root biomass, and total leaf area, whilst the increased effect was ranked as C. etunicatum > D. spurca > mixed-AMF > D. versiformis in the decreasing order. Mycorrhizal inoculation also considerably increased total root length and volume, whereas obviously inhibited root-hair length and number, in company with an increment in root-hair diameter. Leaf N, P, K, Ca, Mg, Zn, and Mn contents were significantly higher in AMF-inoculated plants than in non-AMF-inoculated plants, regardless of AMF species. It concludes that AMF inoculation had positive effects on plant growth performance, root morphology, and leaf nutrient levels in cv. Fuding Dabaicha seedlings, whilst C. etunicatum performed the best effects.
Transition metal ions are key elements of various biological processes ranging from oxygen formation to hypoxia sensing, and therefore, their homeostasis is maintained within strict limits through ...tightly regulated mechanisms of uptake, storage and secretion. The breakdown of metal ion homeostasis can lead to an uncontrolled formation of reactive oxygen species, ROS (via the Fenton reaction, which produces hydroxyl radicals), and reactive nitrogen species, RNS, which may cause oxidative damage to biological macromolecules such as DNA, proteins and lipids. An imbalance between the formation of free radicals and their elimination by antioxidant defense systems is termed oxidative stress. Most vulnerable to free radical attack is the cell membrane which may undergo enhanced lipid peroxidation, finally producing mutagenic and carcinogenic malondialdehyde and 4-hydroxynonenal and other exocyclic DNA adducts. While redox-active iron (Fe) and copper (Cu) undergo redox-cycling reactions, for a second group of redox-inactive metals such as arsenic (As) and cadmium (Cd), the primary route for their toxicity is depletion of glutathione and bonding to sulfhydryl groups of proteins. While arsenic is known to bind directly to critical thiols, other mechanisms, involving formation of hydrogen peroxide under physiological conditions, have been proposed. Redox-inert zinc (Zn) is the most abundant metal in the brain and an essential component of numerous proteins involved in biological defense mechanisms against oxidative stress. The depletion of zinc may enhance DNA damage by impairing DNA repair mechanisms. Intoxication of an organism by arsenic and cadmium may lead to metabolic disturbances of redox-active copper and iron, with the occurrence of oxidative stress induced by the enhanced formation of ROS/RNS. Oxidative stress occurs when excessive formation of ROS overwhelms the antioxidant defense system, as is maintained by antioxidants such as ascorbic acid, alpha-tocopherol, glutathione (GSH), carotenoids, flavonoids and antioxidant enzymes which include SOD, catalase and glutathione peroxidase. This review summarizes current views regarding the role of redox-active/inactive metal-induced formation of ROS, and modifications to biomolecules in human disease such as cancer, cardiovascular disease, metabolic disease, Alzheimer’s disease, Parkinson’s disease, renal disease, blood disorders and other disease. The involvement of metals in DNA repair mechanisms, tumor suppressor functions and interference with signal transduction pathways are also discussed.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Spirulina is a species of filamentous cyanobacteria that has long been used as a food supplement. In particular,
Spirulina platensis
and
Spirulina maxima
are the most important. Thanks to a high ...protein and vitamin content, Spirulina is used as a nutraceutical food supplement, although its other potential health benefits have attracted much attention. Oxidative stress and dysfunctional immunity cause many diseases in humans, including atherosclerosis, cardiac hypertrophy, heart failure, and hypertension. Thus, the antioxidant, immunomodulatory, and anti-inflammatory activities of these microalgae may play an important role in human health. Here, we discuss the antioxidant, immunomodulatory, and anti-inflammatory activities of Spirulina in both animals and humans, along with the underlying mechanisms. In addition, its commercial and regulatory status in different countries is discussed as well. Spirulina activates cellular antioxidant enzymes, inhibits lipid peroxidation and DNA damage, scavenges free radicals, and increases the activity of superoxide dismutase and catalase. Notably, there appears to be a threshold level above which Spirulina will taper off the antioxidant activity. Clinical trials show that Spirulina prevents skeletal muscle damage under conditions of exercise-induced oxidative stress and can stimulate the production of antibodies and up- or downregulate the expression of cytokine-encoding genes to induce immunomodulatory and anti-inflammatory responses. The molecular mechanism(s) by which Spirulina induces these activities is unclear, but phycocyanin and β-carotene are important molecules. Moreover, Spirulina effectively regulates the ERK1/2, JNK, p38, and IκB pathways. This review provides new insight into the potential therapeutic applications of Spirulina and may provide new ideas for future studies.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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