Introduction
Experimental and clinical evidence suggests that estrogens have protective effects in the brain. Nevertheless, their potential role against neurodegenerative diseases, in particular ...Alzheimer’s disease (AD), is still a matter of debate. The identification of the
seladin
-
1
gene (for SELective Alzheimer’s Disease INdicator-1), which appeared to be significantly less expressed in brain region affected in AD, opened a new scenario in the field of neuroprotective mechanisms. Seladin-1 was found to have neuroprotective properties through its anti-apoptotic activity. In addition, it was subsequently demonstrated that seladin-1 also has enzymatic activity, because it catalyzes the conversion of desmosterol into cholesterol. Several studies have shown that an appropriate amount of membrane cholesterol plays a pivotal role to protect nerve cells against β-amyloid toxicity in AD and to counteract the synthesis of β-amyloid.
Methods and Results
We demonstrated that the expression of
seladin
-
1
, as well as the synthesis of cell cholesterol, is stimulated by estrogens in human neuronal precursor cells. Cholesterol enriched cells became more resistant against oxidative stress and β-amyloid toxicity. We thus hypothesized that seladin-1 might be a mediator of the neuroprotective effects of estrogens. Indeed, in cells in which
seladin
-
1
gene expression had been silenced by siRNA the protective effects of estrogens were lost. This finding indicates that seladin-1 is a crucial mediator of the neuroprotective effects of these hormones, at least in our cell model.
Conclusions
In summary, these results establish a new link between estrogens and cholesterol, which is represented by the neuroprotective factor seladin-1.
Advances in ecological immunity have illustrated that, like vertebrates, insects exhibit adaptive immunity, including induced changes in feeding behavior that aid the immune system. In particular, ...recent studies have pointed to the importance of protein intake in mounting an immune response. In this study, we tested the hypothesis that the polyphagous caterpillar Grammia incorrupta (H. Edwards) (Family: Erebidae) would adaptively change its feeding behavior in response to immune challenge, predicting that caterpillars would increase their intake of dietary protein. We further predicted that this response would enhance the melanization response, a component of the immune system that acts against parasitoids. We challenged the immune system using either tachinid fly parasitoids or a bead injection technique that has been used in studies to simulate parasitism, and measured feeding before and after immune challenge on diets varying in their macronutrient content. To evaluate the effects of diet on melanization, we quantified melanization of beads following feeding assays. Contrary to our prediction, we found that parasitized or injected caterpillars given a choice between high- and low-protein foods reduced their intake of the high-protein food. Furthermore, in a no-choice experiment, caterpillars offered food with a protein concentration that is optimal for growth reduced feeding following immune challenge, whereas those offered a low-protein food did not. Although variation in protein intake did not change the caterpillars' melanization response, increased carbohydrate intake did increase melanization, suggesting a prophylactic role for carbohydrates. We discuss alternative mechanisms by which variation in protein intake could negatively or positively affect parasitized caterpillars, including nutritional interactions with the caterpillar's self-medication response.
Austropuccinia psidii
causes rust disease on species within the family Myrtaceae. It was first detected in Australia in 2010, with the first detection in Western Australia in 2022. While species ...within the genus
Melaleuca
from eastern Australia show variable responses to the pathogen, little is known of the response of species from Western Australia. This study established that 13 previously unscreened species of
Melaleuca
, including Threatened and Priority listed species that were grown from seeds sourced from Western Australian populations, were susceptible four months post-germination to the pandemic strain of the pathogen. The proportion of highly susceptible plants within a single species ranged from 2 to 94%, with several species displaying highly variable levels of resistance to
A. psidii
. These results highlight the importance of disease screening and may direct conservation efforts.
ObjectiveTo describe demographic and hormonal characteristics, comorbidities (diabetes mellitus and hypertension), therapeutic procedures and their effectiveness, as well as predictors of morbidity ...and mortality in a nationwide survey of Italian acromegalic patients.DesignRetrospective multicenter epidemiological study endorsed by the Italian Society of Endocrinology and performed in 24 tertiary referral Italian centers. The mean follow-up time was 120 months.ResultsA total of 1512 patients, 41% male, mean age: 45±13 years, mean GH: 31±37 μg/l, IGF1: 744±318 ng/ml, were included. Diabetes mellitus was reported in 16% of cases and hypertension in 33%. Older age and higher IGF1 levels at diagnosis were significant predictors of diabetes and hypertension. At the last follow-up, 65% of patients had a controlled disease, of whom 55% were off medical therapy. Observed deaths were 61, with a standardized mortality ratio of 1.13 95% (confidence interval (CI): 0.87–1.46). Mortality was significantly higher in the patients with persistently active disease (1.93; 95% CI: 1.34–2.70). Main causes of death were vascular diseases and malignancies with similar prevalence. A multivariate analysis showed that older age, higher GH at the last follow-up, higher IGF1 levels at diagnosis, malignancy, and radiotherapy were independent predictors of mortality.ConclusionsPretreatment IGF1 levels are important predictors of morbidity and mortality in acromegaly. The full hormonal control of the disease, nowadays reached in the majority of patients with modern management, reduces greatly the disease-related mortality.
Eucalyptus grandis (W. Hill ex Maiden) is an Australian Myrtaceae tree grown for timber in many parts of the world and for which the annotated genome sequence is available. Known to be susceptible to ...a number of pests and diseases, E. grandis is a useful study organism for investigating defense responses in woody plants. Chitinases are widespread in plants and cleave glycosidic bonds of chitin, the major structural component of fungal cell walls and arthropod exoskeletons. They are encoded by an important class of genes known to be up-regulated in plants in response to pathogens. The current study identified 67 chitinase gene models from two families known as glycosyl hydrolase 18 and 19 (36 GH18 and 31 GH19) within the E. grandis genome assembly (v1.1), indicating a recent gene expansion. Sequences were aligned and analyzed as conforming to currently recognized plant chitinase classes (I-V). Unlike other woody species investigated to date, E. grandis has a single gene encoding a putative vacuolar targeted Class I chitinase. In response to Leptocybe invasa (Fisher & La Salle) (the eucalypt gall wasp) and Chrysoporthe austroafricana (Gryzenhout & M.J. Wingf. 2004) (causal agent of fungal stem canker), this Class IA chitinase is strongly up-regulated in both resistant and susceptible plants. Resistant plants, however, indicate greater constitutive expression and increased up-regulation than susceptible plants following fungal challenge. Up-regulation within fungal resistant clones was further confirmed with protein data. Clusters of putative chitinase genes, particularly on chromosomes 3 and 8, are significantly up-regulated in response to fungal challenge, while a cluster on chromosome 1 is significantly down-regulated in response to gall wasp. The results of this study show that the E. grandis genome has an expanded group of chitinase genes, compared with other plants. Despite this expansion, only a single Class I chitinase is present and this gene is highly up-regulated within diverse biotic stress conditions. Our research provides insight into a major class of defense genes within E. grandis and indicates the importance of the Class I chitinase.
•How do long-lived trees respond effectively to fast-evolving pathogens?•Is there evidence for dynamic pathogen-specific recognition within tree defence genes?•We propose that tree defence uses a ...three-pronged genomic approach.•This involves gene numbers, genomic architecture, and lifetime mutation loads.
Perennial plants need to cope with changing environments and pathogens over their lifespan. Infections are compartmentalised by localised physiological responses, and multiple apical meristems enable repair and regrowth, but genes are another crucial component in the perception and response to pathogens. In this opinion article we suggest that the mechanism for dynamic pathogen-specific recognition in long-lived plants could be explained by extending our current understanding of plant defence genes. We propose that, in addition to physiological responses, tree defence uses a three-pronged genomic approach involving: (i) gene numbers, (ii) genomic architecture, and (iii) mutation loads accumulated over long lifespans.
Eucalyptus grandis is a commercially important hardwood species and is known to be susceptible to a number of pests and pathogens. Determining mechanisms of defense is therefore a research priority. ...The published genome for E. grandis has aided the identification of one important class of resistance (R) genes that incorporate nucleotide binding sites and leucine-rich repeat domains (NBS-LRR). Using an iterative search process we identified NBS-LRR gene models within the E. grandis genome. We characterized the gene models and identified their genomic arrangement. The gene expression patterns were examined in E. grandis clones, challenged with a fungal pathogen (Chrysoporthe austroafricana) and insect pest (Leptocybe invasa). One thousand two hundred and fifteen putative NBS-LRR coding sequences were located which aligned into two large classes, Toll or interleukin-1 receptor (TIR) and coiled-coil (CC) based on NB-ARC domains. NBS-LRR gene-rich regions were identified with 76% organized in clusters of three or more genes. A further 272 putative incomplete resistance genes were also identified. We determined that E. grandis has a higher ratio of TIR to CC classed genes compared to other woody plant species as well as a smaller percentage of single NBS-LRR genes. Transcriptome profiles indicated expression hotspots, within physical clusters, including expression of many incomplete genes. The clustering of putative NBS-LRR genes correlates with differential expression responses in resistant and susceptible plants indicating functional relevance for the physical arrangement of this gene family. This analysis of the repertoire and expression of E. grandis putative NBS-LRR genes provides an important resource for the identification of novel and functional R-genes; a key objective for strategies to enhance resilience.
Data regarding the prevalence of metallo-beta-lactamases (MBLs) among Pseudomonas aeruginosa isolates in cystic fibrosis patients are scarce. Furthermore, there is limited knowledge on the effect of ...MBL production on patient outcomes. Here we describe a fatal respiratory infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient and the results of the subsequent epidemiological investigation. This is the first description of a fatal infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient. The circulation of P. aeruginosa isolates harboring MBLs pose a substantial risk to the cystic fibrosis population due to the limited therapeutic options available and their spreading potential.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Defensive mixology Mason, Peri A.; Singer, Michael S.
Functional ecology,
04/2015, Letnik:
29, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Summary
The myriad chemicals produced by plants may act in combination to enhance chemical defence against herbivores. Many animals have evolved the ability to harness plant secondary metabolites ...(PSMs) and other chemical resources for their own defence, but few studies have addressed the compelling notion that non‐human animals combine exogenous chemicals from different sources to defend themselves against predators, parasites and pathogens.
We consider the use of ‘defensive cocktails’ from an evolutionary ecology perspective, introducing the term, ‘acquired combinatorial chemical defence’ (ACCD). We define ACCD as the adaptive use of multiple chemicals of discrete origin resulting in defence against natural enemies.
First, we discuss the defining characteristics of ACCD: the ability to harness interspecific chemical variation, to independently regulate it, and to obtain defensive benefits via synergy that exceed those associated with single sources.
Then, we describe three non‐mutually exclusive modes by which acquired chemicals may operate against natural enemies: different chemical resources may provide defence during different stages of development, may be effective against different enemies or may work additively or synergistically against a given enemy at a given developmental stage.
Next, we describe possible avenues by which chemical combinations may be acquired by herbivores and other taxa, including the mixing of exogenous chemicals from different items in the diet and mixing chemicals of dietary origin with those from non‐food resources. We discuss possible costs of ACCD, including detoxification costs and interactions with the immune system, and discuss methods of testing for ACCD and its costs.
Finally, we discuss the evolutionary prediction that herbivores may converge on the use of complementary combinations of chemical resources from the environment or chemical defence syndromes. Opportunities to combine chemical resources abound, suggesting that animal and human medication may be more closely aligned than previously recognized.
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