1,721,030 research outputs found
MicroRNA-mediated stress response in bivalve species
No full textBivalve mollusks are important aquatic organisms, which are used for biological monitoring because of their abundance, ubiquitous nature, and abilities to adapt to different environments. MicroRNAs (miRNAs) are small noncoding RNAs, which typically silence the expression of target genes; however, certain miRNAs directly or indirectly upregulate their target genes. They are rapidly modulated and play an essential role in shaping the response of organisms to stresses. Based on the regulatory function and rapid alteration of miRNAs, they could act as biomarkers for biotic and abiotic stress, including environmental stresses and contaminations. Moreover, mollusk, particularly hemocytes, rapidly respond to environmental changes, such as pollution, salinity changes, and desiccation, which makes them an attractive model for this purpose. Thus, bivalve mollusks could be considered a good animal model to examine a system's response to different environmental conditions and stressors. miRNAs have been reported to adjust the adaptation and physiological functions of bivalves during endogenous and environmental stressors. In this review, we aimed to discuss the potential mechanisms underlying the response of bivalves to stressors and how miRNAs orchestrate this process; however, if necessary, other organisms’ response is included to explain specific processes
An attempt to determine the mechanisms of Cl-exit across the basolateral membrane of eel intestine: use of different Cl-transport pathway inhibitors
No full textComparison of Cl-absorption in the intestine of the seawater- and freshwater-adapted eel,Anguilla anguilla: evidence for the presence of an Na-K-Cl cotransport system on the luminal membrane of the enterocyte
No full textCa2+ regulation of paracellular permeability in the middle intestine of the eel, Anguilla anguilla.
No full textThe role of Ca++ on the regulation of the paracellular pathway permeability of the middle intestine of Anguilla anguilla was studied by measuring the transepithelial resistance and the dilution potential, generated when one half of NaCl in the mucosal solution was substituted iso-osmotically with mannitol, in various experimental conditions altering extracellular and/or intracellular calcium levels. We found that removal of Ca++ in the presence of ethylene glycol-bis(β-aminoethyl ether) (EGTA) from both the mucosal and the serosal side, but not from one side only, reduced both the transepithelial resistance and the magnitude of the dilution potential. The irreversibility of this effect suggests a destruction of the organization of the junction in the nominal absence of Ca++. However a modulatory role of extracellular Ca++ cannot be excluded. The decrease of the intracellular Ca++ activity, produced by using verapamil to block the Ca++ entry into the cell, or by adding 3,4,5-trimethoxybenzoic acid 8-(diethylamino) octyl ester (hydrochloride) (TMB-8), an inhibitor of Ca++ release from the intracellular stores, reduced both the transepithelial resistance and the magnitude of the dilution potential, indicating a role of cytosolic Ca++ in the modulation of the paracellular permeability. However the rise of calcium activity produced by the Ca++ ionophore calcimycin (A23187) evoked an identical effect, suggesting that any change in physiological intracellular Ca++ activity alters the paracellular permeability
Daily rhythm of total activity/rest pattern in small and large domestic animals
Full text linkCircadian rhythms represent an inherent property of living organ- isms that seem to guarantee an optimal functioning of the biological system, with maximum efficiency, performance and welfare.1 In mam- mals, a master clock located in the suprachiasmatic nuclei (SCN) of the hypothalamus adjusts the timing of other self-sustained oscillators in the brain and peripheral organs.2 In most species, the daily light- dark (L/D) cycle is the primary environmental stimulus (Zeitgeber) for the entrainment of the SCN pacemaker. The SCN receives light infor- mation from the retina and regulates several physiological processes by synchronizing molecular clockwork mechanisms consisted by a core group of clock genes in each cell.3 Among all physiological processes, the total locomotor activity (TLA) is one of the most susceptible to the L/D cycle. Light acutely suppresses locomotor activity in nocturnal (night active) animals such as rats and owls but promotes activity in diurnal (day active) animals like dogs and eagles.4 Since animals have a species-typical organization of activity patterns,5 the aim of this study was to compare the TLA in small and large domestic animals like rabbits, cats, dogs, goats, sheep, cows, donkeys and horses. Five clini- cally healthy female subjects from eight different species: rabbits (body weight 2.5±0.2 kg), cats (body weight 4.5±0.3 kg), dogs (body weight 13.5±1 kg), goats (body weight 40±2 kg), sheep (body weight 45±2 kg), cows (body weight 390±10 kg), donkeys (body weight 395±20) and horses (body weight 565±42) were enrolled in the study with owners consent. Animals were housed under natural photoperiod (March) 12:12 hours L/D cycle (5.30 am sunrise, 5.30 pm sunset) according to specific farm management, except for cats and dogs that lived outdoors. Water was available ad libitum and feeding was suit- able for each species. Total activity pattern was recorded for 10 days using actigraphy-based data loggers Actiwatch-Mini (Cambridge Neurotechnology Ltd, UK) placed on each animal through collars or halters according to the species. Activity was monitored with a sam- pling interval of 5 minutes. Total daily amount of activity, mount of activity during the photophase and the scotophase were calculated
using Actiwatch Activity Analysis 5.06 (Cambridge Neurotechnology Ltd, UK). The Cosine peak of a rhythm (the time of the daily peak) was computed by cosinor rhythmometry6 as implement in the Actiwatch Activity Analysis 5.06 program. The temporal resolution of the locomo- tor activity data was reduced to t h bins by the averaging of all 15 data points within each 1 h bin to apply the statistical analysis. To analyze the locomotor activity a trigonometric statistical model was applied to each time series to statistically describe the periodic phenomenon, by characterizing the main rhythmic parameters according to the single cosinor procedure.6 Four rhythmic parameters were determined: mean level, amplitude, acrophase (the time at which the peak of a rhythm occurs), and robustness (strength of rhythmicity). For each animal, the mean level of the rhythm was computed as the arithmetic mean of all values in the data set (24 data points). The amplitude of the rhythm was calculated as half the maximum-minimum range of the oscilla- tion, which was computed as the difference between peak and trough. Robustness was computed as the percentage of the maximal score attained by the chi-square periodogram statistic for ideal data sets of comparable size and 24-h periodicity.7 Two-way analysis of variance (ANOVA) was used for the assessment of effects due to species and days on the daily amount of activity per 24 h. Statistical analysis showed significant differences among domestic species. The highest daily amount of activity was observed during the photophase (p<0.0001) in dogs, sheep, goats, cows, donkeys and horses, and dur- ing the scotophase (p<0.0001) in rabbits and cats. Our results show different pattern of locomotor activity in every domestic species (Figure 1), underlining a diurnal pattern of locomotor activity in dogs, goats, sheep, cows, donkeys and horses while rabbits and cats have a main nocturnal pattern. As previously observed by several authors,8-10 our study confirms that locomotor activity exhibits a robust daily rhythmicity during the photophase in dogs, cows and horses, therefore in these species the rhythm can be poorly affected by external stimuli. On the contrary, other domestic species can spontaneously shift from diur- nal to nocturnal activity pattern. Sheep with restricted night time feed- ing can shift the main bout of activity during the night8 or cats, that are considered mainly nocturnal, use to loose their rhythm when they live in symbiosis with humans.11 Therefore, the daily pattern of TLA does not depend only on L/D cycle but it can be affected by several environ- mental variables including different activities such as feeding, drink- ing, walking, grooming, playing as well as all conscious and uncon- scious movements
Pinna nobilis: A big bivalve with big haemocytes?
No full textThe fan mussel Pinna nobilis (Linnaeus, 1758) is one of the biggest bivalves worldwide. Currently, no
updated information is available in the literature concerning the morpho-functional aspects of haemocytes
from this bivalve species. Consequently, in this study, we characterised P. nobilis haemocytes from
both a morphological and functional point of view. The mean number of haemocytes was about 5
(105) cells mL haemolymph1, and the cell viability was about 92e100%. Two haemocyte types were
distinguished under the light microscope: granulocytes (51.6%), with evident cytoplasmic granules, and
hyalinocytes (48.4%), with a few granules. The granules of the granulocytes were mainly lysosomes, as
indicated by the in vivo staining with Neutral Red. Haemocytes were further distinguished in basophils
(83.75%), acidophils (14.75%) and neutrophils (1.5%). After adhesion to slides and fixation, the cell
diameter was approximately 10 mm for granulocytes and 7 mm for hyalinocytes. The granulocytes and
hyalinocytes were both positive to the Periodic Acid-Schiff reaction for carbohydrates. Only granulocytes
were able to phagocytise yeast cells. The phagocytic index (6%) increased significantly up to twofold after
preincubation of yeast in cell-free haemolymph, suggesting that haemolymph has opsonising properties.
In addition, haemocytes produce superoxide anion and acid and alkaline phosphatases. Summarising,
this preliminary study indicates that both the granulocytes and hyalinocytes circulate in the haemolymph
of P. nobilis and that they are active immunocytes
Daily rhythm of total activity/rest pattern in small and large domestic animals
No full textCircadian rhythms represent an inherent property of living organ- isms that seem to guarantee an optimal functioning of the biological system, with maximum efficiency, performance and welfare.1 In mam- mals, a master clock located in the suprachiasmatic nuclei (SCN) of the hypothalamus adjusts the timing of other self-sustained oscillators in the brain and peripheral organs.2 In most species, the daily light- dark (L/D) cycle is the primary environmental stimulus (Zeitgeber) for the entrainment of the SCN pacemaker. The SCN receives light infor- mation from the retina and regulates several physiological processes by synchronizing molecular clockwork mechanisms consisted by a core group of clock genes in each cell.3 Among all physiological processes, the total locomotor activity (TLA) is one of the most susceptible to the L/D cycle. Light acutely suppresses locomotor activity in nocturnal (night active) animals such as rats and owls but promotes activity in diurnal (day active) animals like dogs and eagles.4 Since animals have a species-typical organization of activity patterns,5 the aim of this study was to compare the TLA in small and large domestic animals like rabbits, cats, dogs, goats, sheep, cows, donkeys and horses. Five clini- cally healthy female subjects from eight different species: rabbits (body weight 2.5±0.2 kg), cats (body weight 4.5±0.3 kg), dogs (body weight 13.5±1 kg), goats (body weight 40±2 kg), sheep (body weight 45±2 kg), cows (body weight 390±10 kg), donkeys (body weight 395±20) and horses (body weight 565±42) were enrolled in the study with owners consent. Animals were housed under natural photoperiod (March) 12:12 hours L/D cycle (5.30 am sunrise, 5.30 pm sunset) according to specific farm management, except for cats and dogs that lived outdoors. Water was available ad libitum and feeding was suit- able for each species. Total activity pattern was recorded for 10 days using actigraphy-based data loggers Actiwatch-Mini (Cambridge Neurotechnology Ltd, UK) placed on each animal through collars or halters according to the species. Activity was monitored with a sam- pling interval of 5 minutes. Total daily amount of activity, mount of activity during the photophase and the scotophase were calculated
using Actiwatch Activity Analysis 5.06 (Cambridge Neurotechnology Ltd, UK). The Cosine peak of a rhythm (the time of the daily peak) was computed by cosinor rhythmometry6 as implement in the Actiwatch Activity Analysis 5.06 program. The temporal resolution of the locomo- tor activity data was reduced to t h bins by the averaging of all 15 data points within each 1 h bin to apply the statistical analysis. To analyze the locomotor activity a trigonometric statistical model was applied to each time series to statistically describe the periodic phenomenon, by characterizing the main rhythmic parameters according to the single cosinor procedure.6 Four rhythmic parameters were determined: mean level, amplitude, acrophase (the time at which the peak of a rhythm occurs), and robustness (strength of rhythmicity). For each animal, the mean level of the rhythm was computed as the arithmetic mean of all values in the data set (24 data points). The amplitude of the rhythm was calculated as half the maximum-minimum range of the oscilla- tion, which was computed as the difference between peak and trough. Robustness was computed as the percentage of the maximal score attained by the chi-square periodogram statistic for ideal data sets of comparable size and 24-h periodicity.7 Two-way analysis of variance (ANOVA) was used for the assessment of effects due to species and days on the daily amount of activity per 24 h. Statistical analysis showed significant differences among domestic species. The highest daily amount of activity was observed during the photophase (p<0.0001) in dogs, sheep, goats, cows, donkeys and horses, and dur- ing the scotophase (p<0.0001) in rabbits and cats. Our results show different pattern of locomotor activity in every domestic species (Figure 1), underlining a diurnal pattern of locomotor activity in dogs, goats, sheep, cows, donkeys and horses while rabbits and cats have a main nocturnal pattern. As previously observed by several authors,8-10 our study confirms that locomotor activity exhibits a robust daily rhythmicity during the photophase in dogs, cows and horses, therefore in these species the rhythm can be poorly affected by external stimuli. On the contrary, other domestic species can spontaneously shift from diur- nal to nocturnal activity pattern. Sheep with restricted night time feed- ing can shift the main bout of activity during the night8 or cats, that are considered mainly nocturnal, use to loose their rhythm when they live in symbiosis with humans.11 Therefore, the daily pattern of TLA does not depend only on L/D cycle but it can be affected by several environ- mental variables including different activities such as feeding, drink- ing, walking, grooming, playing as well as all conscious and uncon- scious movements
Growth and liver histology of Channa punctatus exposed to a common biofertilizer
No full textMustard oil cake (MOC) is widely used as biofertilizer in the field of agriculture and aquaculture. Channa punctatus was exposed to 0.42 g.L−1 sublethal concentration for 4, 7, 14, 21 and 28 days. Due to such exposure, body growth and histological changes in liver were observed. It was revealed that weight, length and breadth of fish were gradually increased with the days of exposure in compare to control fish, whereas, liver showed an increase in sinusoidal space and lipidosis during early days, followed by a recovery from the stress of MOC on the 28th day
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