95 research outputs found
Amphibian peptides for skin protection and healing
BACKGROUND: Amphibians are currently suffering a dramatic decline worldwide, mainly due to chytridiomycosis, a skin infection caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). An important natural defense of amphibian skin is the production of antimicrobial peptides (AMPs) by granular glands in the dermis. AMPs collected from several species of frogs successfully inhibit the growth of Bd in vitro. Besides their anti-microbial and anti-fungal activities, AMPs have been shown to exert other biological effects such as anti-viral, anti-tumor, anti-oxidant, immunomodulating and wound healing.
AIM: We intended to test the efficacy of AMPs as cutaneous defenses in frog species either resistant or susceptible to Bd.
METHODS: 3 frog species (Gastrotheca nebulanastes (GN), G. excubitor (GE) and Hypsiboas gladiator (HG), were collected in montane scrub, cloud forest and high elevation grassland habitats near Manu National Park in southeastern Peru. AMP secretion was stimulated by injection of norepinephrine into the dorsal lymph sacks. AMPs were then purified by chromatographic techniques. The human endothelial cell line HECV was treated with AMP concentrations ranging from 0.005 to 50 \ub5g/mL. Cell viability was verified by MTT test. Wound healing properties were analyzed by scratch wound assay. AMP inhibition strength against Bd growth was measured in vitro by incubating Bd zoospores with different concentrations of AMPs.
RESULTS: Treatment with AMPs secreted from GN, GE and HG did not affect HECV cell viability at any concentration tested. No significant differences in cell migration rate were observed in HECV cells scratched and treated with GN and GE AMPs. Only HG peptides showed wound healing properties as well as strong Bd growth inhibiting ability.
CONCLUSIONS: Stimulation of wound healing mechanisms and inhibition of Bd growth by skin AMPs might both contribute to HG resistance to chytridiomycosis. Understanding the role of skin defenses may lead to the development of novel Bd mitigation strategies. Possible applications of amphibian AMPs in skin medicine deserve attention and further studies.
This work was funded by the European Commission (Tender ENV.B.3/SER/2016/0028, Mitigating a new infectious disease in salamanders to counteract the loss of European biodiversity) and by Parco Nazionale delle Cinque Terre
Thalamocortical bistable switch as a theoretical model of fibromyalgia pathogenesis inferred from a literature survey
Fibromyalgia (FM) is an unsolved central pain processing disturbance. We aim to provide a unifying model for FM pathogenesis based on a loop network involving thalamocortical regions, i.e., the ventroposterior lateral thalamus (VPL), the somatosensory cortex (SC), and the thalamic reticular nucleus (TRN). The dynamics of the loop have been described by three differential equations having neuron mean firing rates as variables and containing Hill functions to model mutual interactions among the loop elements. A computational analysis conducted with MATLAB has shown a transition from monostability to bistability of the loop behavior for a weakening of GABAergic transmission between TRN and VPL. This involves the appearance of a high-firing-rate steady state, which becomes dominant and is assumed to represent pathogenic pain processing giving rise to chronic pain. Our model is consistent with a bulk of literature evidence, such as neuroimaging and pharmacological data collected on FM patients, and with correlations between FM and immunoendocrine conditions, such as stress, perimenopause, chronic inflammation, obesity, and chronic dizziness. The model suggests that critical targets for FM treatment are to be found among immunoendocrine pathways leading to GABA/glutamate imbalance having an impact on the thalamocortical system
3,5-Diiodo-L-thyronine modulates the expression of genes of lipid metabolism in a rat model of fatty liver.
Recent reports demonstrated that 3,5-diiodo-l-thyronine (T(2)) was able to prevent lipid accumulation in the liver of rats fed a high-fat diet (HFD). In this study, we investigated how the rat liver responds to HFD and T(2) treatment by assessing the transcription profiles of some genes involved in the pathways of lipid metabolism: oxidation, storage and secretion. The mRNA levels of the peroxisome proliferator-activated receptors (PPARα, PPARγ and PPARδ), and of their target enzymes acyl-CoA oxidase and stearoyl-CoA desaturase were evaluated by real-time RT-PCR. Moreover, the expression of the adipose triglyceride lipase involved in lipid mobilisation, of the main PAT proteins acting in lipid droplet (LD) turnover, and of apoprotein B (apo B), the major protein component of very low-density lipoproteins (VLDLs) were analysed. Overall, our data demonstrated that T(2) administration to HFD rats counteracts most of the hepatic transcriptional changes that occurred in response to the excess exogenous fat. In particular, our results suggest that T(2) may prevent the pathways leading to lipid storage in LDs, promote the processes of lipid mobilisation from LDs and secretion as VLDL, in addition to the stimulation of pathways of lipid oxidation. In conclusion, our findings might give an insight into the mechanisms underlying the anti-steatotic ability of T(2) and help to define the potential therapeutic role of T(2) for preventing or treating liver steatosis
Precise Measurements of Branching Fractions for Meson Decays to Two Pseudoscalar Mesons
We measure the branching fractions for seven two-body decays to
pseudo-scalar mesons, by analyzing data collected at
GeV with the BESIII detector at the BEPCII collider. The branching fractions
are determined to be ,
,
,
,
,
,
,
where the first uncertainties are statistical, the second are systematic, and
the third are from external input branching fraction of the normalization mode
. Precision of our measurements is significantly improved
compared with that of the current world average values
Observation of the Singly Cabibbo-Suppressed Decay and Evidence for
Based on 2.93 fb collision data taken at center-of-mass
energy of 3.773 GeV by the BESIII detector, we report searches for the singly
Cabibbo-suppressed decays and .
A double tag technique is used to measure the absolute branching fractions
and
, with
statistical significances of and , respectively. We also
present measurements of the absolute branching fractions for the related decay modes. We find
and
, which are
consistent with the current world averages. The first and second uncertainties
are statistical and systematic, respectively
Measurements of Weak Decay Asymmetries of , , , and
Using production from a 567 pb
data sample collected by BESIII at 4.6 GeV, a full angular analysis is carried
out simultaneously on the four decay modes of , , , and . For the first time, the
transverse polarization is studied in unpolarized
collisions, where a non-zero effect is observed with a statistical significance
of 2.1. The decay asymmetry parameters of the weak
hadronic decays into , , and
are measured to be ,
,
, and
, respectively. In comparison with
previous results, the measurements for the and
modes are consistent but with improved precision, while the parameters for the
and modes are measured for the first time
Scripta in honorem Igor Fisković: zbornik povodom sedamdesetog rođendana
The International Research Centre for Late Antiquity and the Middle Ages prepared a Festschrift in honour of one of its founders, Igor Fisković on the occassion of his 70th birthday. The Festschrift includes works addressing the periods that Igor Fisković has dealt with most, thus reflecting the diversity of his interests, ranging from Late Antiquity to contemporary art, with key emphasis on the Late Middle Ages and early modernity. Due to the diversity and the broad period of time the texts are covering, they have been arranged more or less chronologically. The works focus mainly on the Late Middle Ages and the early modern period, Fisković’s forte and the topic of some of his best writings. There are also several texts addressing the baroque period, which was not one of the honouree’s interests, but they were written by some of his closest friends and members of the generation of his former students who have had prestigious careers. (from the Foreword)Zbornik je pripredio Međunarodni istraživački centar za kasnu antiku i srednji vijek povodom sedamdesetog rođendana jednog od svojih osnivača Igora Fiskovića. Zbornik obuhvaća radove koje pokrivaju razdoblja kojima se Igor Fisković ponajviše bavio, reflektirajući raznolikost njegovih interesa, od početne kasne antike i suvremene umjetnosti, do ključnoga naglaska na kasnom srednjem vijeku i početku modernog doba. Zbog te raznolikosti i širokog vremenskog razdoblja koje pokrivaju, radovi su poredani manje-više kronološki. Ističe se brojem radova upravo kasnosrednjovjekovno doba i početci modernoga, forte u kojem je Igor Fisković dao svoje ponajbolje radove. Uz njih je i više priloga koji pokrivaju razdoblje baroka, kojim se slavljenik nije bavio, no koji su iz pera njegovih najbliskijih prijatelja i one generacije njegovih bivših studenata koji su danas ostvarili ugledne karijere. (iz Predgovora
Scripta in honorem Igor Fisković: zbornik povodom sedamdesetog rođendana
The International Research Centre for Late Antiquity and the Middle Ages prepared a Festschrift in honour of one of its founders, Igor Fisković on the occassion of his 70th birthday. The Festschrift includes works addressing the periods that Igor Fisković has dealt with most, thus reflecting the diversity of his interests, ranging from Late Antiquity to contemporary art, with key emphasis on the Late Middle Ages and early modernity. Due to the diversity and the broad period of time the texts are covering, they have been arranged more or less chronologically. The works focus mainly on the Late Middle Ages and the early modern period, Fisković’s forte and the topic of some of his best writings. There are also several texts addressing the baroque period, which was not one of the honouree’s interests, but they were written by some of his closest friends and members of the generation of his former students who have had prestigious careers. (from the Foreword)Zbornik je pripredio Međunarodni istraživački centar za kasnu antiku i srednji vijek povodom sedamdesetog rođendana jednog od svojih osnivača Igora Fiskovića. Zbornik obuhvaća radove koje pokrivaju razdoblja kojima se Igor Fisković ponajviše bavio, reflektirajući raznolikost njegovih interesa, od početne kasne antike i suvremene umjetnosti, do ključnoga naglaska na kasnom srednjem vijeku i početku modernog doba. Zbog te raznolikosti i širokog vremenskog razdoblja koje pokrivaju, radovi su poredani manje-više kronološki. Ističe se brojem radova upravo kasnosrednjovjekovno doba i početci modernoga, forte u kojem je Igor Fisković dao svoje ponajbolje radove. Uz njih je i više priloga koji pokrivaju razdoblje baroka, kojim se slavljenik nije bavio, no koji su iz pera njegovih najbliskijih prijatelja i one generacije njegovih bivših studenata koji su danas ostvarili ugledne karijere. (iz Predgovora
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