Phagocytic efficiency and cytotoxic responses of Indian freshwater sponge (Eunapius carteri) cells isolated by density gradient centrifugation and flow cytometry: a morphofunctional analysis

The freshwater sponge Eunapius carteri (Porifera: Demospongiae: Spongillidae), a resident of Indian freshwater ecosystems, has pharmaceutical and ecological potential, but there is inadequate information on its cellular spectrum and cell-mediated immune responses. Microscopical analysis revealed the existence of eight distinct cellular variants, i.e. blast-like cells, choanocytes, small amoebocytes, granular cells, pinacocytes, large amoebocytes, archaeocytes and sclerocytes. The cells were isolated by density gradient centrifugation and flow cytometry and used for a morphofunctional analysis. We investigated the phagocytic efficiency of E. carteri cells under the challenge of yeast particles in vitro and spectrophotometrically quantified the generation of cytotoxic molecules (superoxide anions and nitric oxide) in different isolated cellular fractions. The two cell separating technologies did not yield any significant differences in the major findings on morphology, phagocytic response and generation of superoxide anions and nitric oxide. Archaeocytes, granular cells and large amoebocytes were identified as chief phagocytes with a high phagocytic potential as recorded by light microscopy. Archaeocytes were the principal generators of superoxide anions, whereas nitric oxide was recorded in the fractions rich in archaeocytes and large amoebocytes. The present investigation thus provides useful information regarding cellular variation, cytotoxic status and innate phagocytic response of the cells of E. carteri, a common but less studied sponge of India.     

Water temperature: A factor in the seasonality of two freshwater sponge species,Ephydatia fluviatilis and Spongilla alba

Two freshwater sponge species, Ephvdatia fluviatilis and Spongilla alba, were maintained in a continuous-flow laboratory culture system at several different water temperatures. Experimental results suggest that sponge growth rate is affected by water temperature and that it is affected differently in the two species. The results correlate well with field observations on species abundance at different water temperatures and thereby support the view that water temperature is a factor determining seasonality in these species.     

Pyrosequencing reveals highly diverse and species-specific microbial communities in sponges from the Red Sea

Marine sponges are associated with a remarkable array of microorganisms. Using a tag pyrosequencing technology, this study was the first to investigate in depth the microbial communities associated with three Red Sea sponges, Hyrtios erectus, Stylissa carteri and Xestospongia testudinaria. We revealed highly diverse sponge-associated bacterial communities with up to 1000 microbial operational taxonomic units (OTUs) and richness estimates of up to 2000 species. Altogether, 26 bacterial phyla were detected from the Red Sea sponges, 11 of which were absent from the surrounding sea water and 4 were recorded in sponges for the first time. Up to 100 OTUs with richness estimates of up to 300 archaeal species were revealed from a single sponge species. This is by far the highest archaeal diversity ever recorded for sponges. A non-negligible proportion of unclassified reads was observed in sponges. Our results demonstrated that the sponge-associated microbial communities remained highly consistent in the same sponge species from different locations, although they varied at different degrees among different sponge species. A significant proportion of the tag sequences from the sponges could be assigned to one of the sponge-specific clusters previously defined. In addition, the sponge-associated microbial communities were consistently divergent from those present in the surrounding sea water. Our results suggest that the Red Sea sponges possess highly sponge-specific or even sponge-species-specific microbial communities that are resistant to environmental disturbance, and much of their microbial diversity remains to be explored.     

Compositional analysis of archaeal communities in high and low microbial abundance sponges in the Misool coral reef system,Indonesia

The high/low microbial abundance (HMA/LMA) dichotomy in sponges has been the subject of several studies over recent years, but few studies have analysed this dichotomy in terms of the sponge archaeal community and function. Using a 16S rRNA gene barcoded pyrosequencing approach and predictive functional analysis (PICRUSt) we compared the archaeal composition, richness and predicted function of one HMA sponge (Xestospongia testudinaria), one LMA sponge (Stylissa carteri) and one sponge species of unknown microbial abundance (Aaptos lobata). Although most of the archaeal sequences were assigned to the Crenarchaeota phylum, S. carteri had the highest percentage of sequences assigned to the Euryarchaeota phylum. Variation among sponge species explained >85% of the variation in archaeal operational taxonomic unit (OTU) composition with each sponge species forming a distinct cluster. There were significant differences in predicted PICRUSt profiles among sponge species, suggesting that archaeal communities present in the studied sponge species may perform different functions. X. testudinaria and A. lobata were similar both in terms of OTU and KEGG orthologues composition, which may indicate that A. lobata is a HMA sponge. Additionally, some of the most enriched functions seem to be related to traits associated with high and low microbial abundance sponges.     

Photoinactivation of Catalase Occurs under Both High- and Low-Temperature Stress Conditions and Accompanies Photoinhibition of Photosystem II

Severe photoinactivation of catalase (EC 1.11.1.6) and a decline of variable fluorescence (F_v), indicating photoinhibition of photosynthesis, were observed as rapid and specific symptoms in leaves exposed to a high heat-shock temperature of 40°C as well as in leaves exposed to low chilling temperatures in white light of only moderately high photosynthetic photon flux density of 520 μE m⁻² s⁻¹. Other parameters, such as peroxidase (EC 1.11.1.7), glycolate oxidase (EC 1.1.3.1), glutathione reductase (EC 1.6.4.2), or the chlorophyll content, were hardly affected under these conditions. At a compatible temperature of 22°C, the applied light intensity did not induce severe photoinactivations. In darkness, exposures to high or low temperatures did not affect catalase levels. Also, decline of F_v in light was not related to temperature sensitivity in darkness. The effective low-temperature ranges inducing photoinactivation of catalase differed significantly for chilling-tolerant and chilling-sensitive plants. In leaves of rye (Secale cereale L.) and pea (Pisum sativum L.), photoinactivation occurred only below 15°C, whereas inactivation occurred at 15°C in cucumber (Cucumis sativus L.) and maize (Zea mays L.). The behavior of F_v was similar, but the difference between chilling-sensitive and chilling-tolerant plants was less striking. Whereas the catalase polypeptide, although photoinactivated, was not cleaved at 0 to 4°C, the D1 protein of photosystem II was greatly degraded during the low-temperature treatment of rye leaves in light. Rye leaves did not exhibit symptoms of any major general photodamage, even when they were totally depleted of catalase after photoinactivation at 0 to 4°C, and catalase recovered rapidly at normal temperature. In cucumber leaves, the decline of catalase after exposures to bright light at 0 to 4°C was accompanied by bleaching of chlorophyll, and the recovery observed at 25°C was slow and required several days. Similar to the D1 protein of photosystem II, catalase differs greatly from other proteins by its inactivation and high turnover in light. Inasmuch as catalase and D1 protein levels depend on continuous repair synthesis, preferential and rapid declines are generally to be expected in light whenever translation is suppressed by stress actions, such as heat or chilling, and recovery will reflect the repair capacity of the plants.     

Effect of growth temperature on photosynthetic capacity and respiration in three ecotypes of Eriophorum vaginatum

Ecotypic differentiation in the tussock‐forming sedge Eriophorum vaginatum has led to the development of populations that are locally adapted to climate in Alaska's moist tussock tundra. As a foundation species, E. vaginatum plays a central role in providing topographic and microclimatic variation essential to these ecosystems, but a changing climate could diminish the importance of this species. As Arctic temperatures have increased, there is evidence of adaptational lag in E. vaginatum, as locally adapted ecotypes now exhibit reduced population growth rates. Whether there is a physiological underpinning to adaptational lag is unknown. Accordingly, this possibility was investigated in reciprocal transplant gardens. Tussocks of E. vaginatum from sites separated by ~1° latitude (Coldfoot: 67°15′N, Toolik Lake: 68°37′, Sagwon: 69°25′) were transplanted into the Toolik Lake and Sagwon sites and exposed to either an ambient or an experimental warming treatment. Five tussocks pertreatment combination were measured at each garden to determine photosynthetic capacity (i.e., V_cmax and J_max) and dark respiration rate (R_d) at measurement temperatures of 15, 20, and 25°C. Photosynthetic enhancements or homeostasis were observed for all ecotypes at both gardens under increased growth temperature, indicating no negative effect of elevated temperature on photosynthetic capacity. Further, no evidence of thermal acclimation in R_d was observed for any ecotype, and there was little evidence of ecotypic variation in R_d. As such, no physiological contribution to adaptational lag was observed given the increase in growth temperature (up to ~2°C) provided by this study. Despite neutral to positive effects of increased growth temperature on photosynthesis in E. vaginatum, it appears to confer no lasting advantage to the species.     

Toxin-Producing Ability among Bacillus spp. Outside the Bacillus cereus Group

A total of 333 Bacillus spp. isolated from foods, water, and food plants were examined for the production of possible enterotoxins and emetic toxins using a cytotoxicity assay on Vero cells, the boar spermatozoa motility assay, and a liquid chromatography-mass spectrometry method. Eight strains produced detectable toxins; six strains were cytotoxic, three strains produced putative emetic toxins (different in size from cereulide), and one strain produced both cytotoxin(s) and putative emetic toxin(s). The toxin-producing strains could be assigned to four different species, B. subtilis, B. mojavensis, B. pumilus, or B. fusiformis, by using a polyphasic approach including biochemical, chemotaxonomic, and DNA-based analyses. Four of the strains produced cytotoxins that were concentrated by ammonium sulfate followed by dialysis, and two strains produced cytotoxins that were not concentrated by such a treatment. Two cultures maintained full cytotoxic activity, two cultures reduced their activity, and two cultures lost their activity after boiling. The two most cytotoxic strains (both B. mojavensis) were tested for toxin production at different temperatures. One of these strains produced cytotoxin at growth temperatures ranging from 25 to 42°C, and no reduction in activity was observed even after 24 h of growth at 42°C. The strains that produced putative emetic toxins were tested for the influence of time and temperature on the toxin production. It was shown that they produced putative emetic toxin faster or just as fast at 30 as at 22°C. None of the cytotoxic strains produced B. cereus-like enterotoxins as tested by PCR or by immunological methods.     

Two Different Rickettsial Bacteria Invading Volvox carteri

BackgroundBacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE.Conclusion/SignificanceAt least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.     

THE CYTOTOXIC PRINCIPLE OF THE PHYTOFLAGELLATE PRYMNESIUM PARVUM

The cytotoxic events leading to lysis induced in Ehrlich ascites tumor (E.A.) cells by Prymnesium parvum cell extracts were followed microscopically and measured quantitatively as changes in E.A. cell volume, uptake of trypan blue, and release of macromolecular constituents from the cells. Cell swelling was the most immediate response to P. parvum cytotoxin, while cell death and lysis were later events distinguished by a decline in cell volume, uptake of dye, and appearance of cellular macromolecules free in the incubation medium. The pH and temperature were shown to affect the outcome of the lytic sequence. At either low pH or temperature, cells swelled but did not lyse until the pH or temperature was raised. On the other hand, cells swollen at the higher pH or temperature could be protected from lysis by lowering either the pH or the temperature.     

Analysis of the Protein Phosphotome of Entamoeba histolytica Reveals an Intricate Phosphorylation Network

Phosphorylation is the most common mechanism for the propagation of intracellular signals. Protein phosphatases and protein kinases play a dynamic antagonistic role in protein phosphorylation. Protein phosphatases make up a significant fraction of eukaryotic proteome. In this article, we report the identification and analysis of protein phosphatases in the intracellular parasite Entamoeba histolytica. Based on an in silico analysis, we classified 250 non-redundant protein phosphatases in E. histolytica. The phosphotome of E. histolytica is 3.1% of its proteome and 1.3 times of the human phosphotome. In this extensive study, we identified 42 new putative phosphatases (39 hypothetical proteins and 3 pseudophosphatases). The presence of pseudophosphatases may have an important role in virulence of E. histolytica. A comprehensive phosphotome analysis of E. histolytica shows spectacular low similarity to human phosphatases, making them potent candidates for drug target.     

Distribution patterns of pelagic euphausiids in the East China Sea

Distribution patterns and abundance of the euphausiids were examined in the East China Sea (23°30′ –33°00′N, 118°30′ –128°00′ E) in relation to temperature and salinity. The data were collected in 4 surveys from 1997 to 2000. The density or yield density model was used to predict optimum temperature and salinity of water for euphausiid distribution, and thereafter distribution patterns of euphausiids were determined based on the predicted parameters. Of 23 species, Euphausia pacifica, E. nana, Pseudeuphausia sinica and P. latifrons were numerically dominant. The analyses indicate that Euphausia pacifica is an offshore temperate water species, E. nana is an offshore temperate warm water species, P. sinica is a coastal subtropical water species and P. latifrons is an oceanic tropical water species. The 4 species occupied 4 different water masses, respectively, namely, cold water mass, cold and warm water mixed masses in winter and spring, cold and warm water mixed masses in summer and autumn, and warm water mass, which could be the good designators of individual water masses, respectively. The predicated optimal temperatures for E. tenera, S. carinatum, E. diomedeae, Stylocheiron affine, Nematoscelis sp., N. gracilis, N. atlantica, Stylocheiron sp. and S. suhmii are all > 25°. These species are mainly distributed in southern Kuroshio in winter and spring, Kuroshio, the Taiwan Warm Current and Tsushima Current in summer and autumn, the equatorial waters of Pacific Ocean and the eastern waters of the Taiwan Strait. They are called as oceanic tropical water species. Nematoscelis tenella and T. tricuspidata are referred to as offshore subtropical water species according to their geographic distributions even if they are halobionts. Euphausia sanzoi is considered as a typical offshore subtropical water species, which inhabited waters below 25°. Stylocheiron microphthalma, occupying warm current waters where temperature and salinity are nearly 25° and 34 in summer and autumn, belongs to oceanic tropical water species. In the same way, E. similes, E. mutica, Euphausia sp., E. brevis and E. recurva are classified into offshore subtropical water species in accordance with the optimum temperature and salinity of waters as well as locations and seasons of their occurrence. Optimum temperature, rather than salinity, is a better parameter in determining the distribution patterns of euphausiids.     

The characteristics of Escherichia coli adsorption of arsenic(III) from aqueous solution

The potential of using Escherichia coli (E. coli) as adsorbent for the adsorption of As(III) from aqueous solution was assessed. Various parameters like pH, initial concentration and temperature have been investigated. It is found that the adsorption of As(III) is pH dependent and the optimum value was 2.0. Kinetics studies revealed that the equilibrium of the adsorption of As(III) on to E. coli was obtained within 30 min and the process was followed with the pseudo-2nd-order kinetic model. The equilibrium adsorption data obtained at different temperatures were fitted better with Langmuir than Freundich isotherm. The adsorption capacity of E. coli for As(III) is increased with the increasing of temperature and the maximum adsorption capacity is 1.111 mg/g which obtained at 40°C. Potentiometric titration and Fourier transform infra-red spectroscopy were applied to reveal the mechanisms of the As(III) binding. Amino, amide, amine group and C–H of the alkane are determined to be involved in As(III) binding based on the results.     

Physicochemical Parameters for Growth of the Sea Ice Bacteria Glaciecola punicea ACAM 611T and Gelidibacter sp. Strain IC158

The water activity and pH ranges for growth of Glaciecola punicea (a psychrophile) were extended when this organism was grown at suboptimal rather than optimal temperatures. No such extension was observed for Gelidibacter sp. strain IC158 (a psychrotolerant bacterium) at analogous temperatures. Salinity and pH may be primary physicochemical parameters controlling bacterial community development in sea ice.     

Comparison of the Thermostability Properties of Three Acid Phosphatases from Molds: Aspergillus fumigatus Phytase, A. niger Phytase, and A. niger pH 2.5 Acid Phosphatase

Enzymes that are used as animal feed supplements should be able to withstand temperatures of 60 to 90°C, which may be reached during the feed pelleting process. The thermostability properties of three histidine acid phosphatases, Aspergillus fumigatus phytase, Aspergillus niger phytase, and A. niger optimum pH 2.5 acid phosphatase, were investigated by measuring circular dichroism, fluorescence, and enzymatic activity. The phytases of A. fumigatus and A. niger were both denatured at temperatures between 50 and 70°C. After heat denaturation at temperatures up to 90°C, A. fumigatus phytase refolded completely into a nativelike, fully active conformation, while in the case of A. niger phytase exposure to 55 to 90°C was associated with an irreversible conformational change and with losses in enzymatic activity of 70 to 80%. In contrast to these two phytases, A. niger pH 2.5 acid phosphatase displayed considerably higher thermostability; denaturation, conformational changes, and irreversible inactivation were observed only at temperatures of ≥80°C. In feed pelleting experiments performed at 75°C, the recoveries of the enzymatic activities of the three acid phosphatases were similar (63 to 73%). At 85°C, however, the recovery of enzymatic activity was considerably higher for A. fumigatus phytase (51%) than for A. niger phytase (31%) or pH 2.5 acid phosphatase (14%). These findings confirm that A. niger pH 2.5 acid phosphatase is irreversibly inactivated at temperatures above 80°C and that the capacity of A. fumigatus phytase to refold properly after heat denaturation may favorably affect its pelleting stability.     

Development and Evaluation of a Model Predicting the Survival of Escherichia coli O157:H7 NCTC 12900 in Homemade Eggplant Salad at Various Temperatures, pHs, and Oregano Essential Oil Concentrations

Homemade eggplant salad, a traditional Greek appetizer, was inoculated with Escherichia coli O157:H7 NCTC 12900 supplemented with different concentrations of oregano essential oil (0.0, 0.7, 1.4, and 2.1% [vol/wt]) and stored at different temperatures (0, 5, 10, and 15°C). The product's pH was adjusted to 4.0, 4.5, or 5.0 with lemon juice. For each combination of the environmental factors, the bacterial counts were modeled, using the Baranyi model, as a function of time to estimate the kinetic parameters of the pathogen. A reduction of more than 1 log unit in E. coli O157:H7 counts was observed in all cases, and the death rate depended on the pH, the storage temperature, and the essential oil concentration. Separate quadratic models were developed with natural logarithms of the shoulder period and death rate as estimated by the growth model, as a function of temperature, pH, and oregano essential oil concentrations. These were further used to predict the population of E. coli O157:H7 NCTC 12900 from other inoculated eggplant salads at random conditions of temperature, pH, and oregano oil concentration. The predicted values were compared with viable-count measurements for validation.     

The effects of intertidal air exposure on the respiratory physiology and the killing activity of hemocytes in the pacific oyster, Crassostrea gigas (Thunberg)

The occurrence of summer mortalities of the commercially important Pacific oyster, Crassostrea gigas, has increased in recent years. These mortality events occur during the late summer when water temperatures are at their highest. Many theories have been proposed concerning the causes including reproductive stress, environmental stress, disease, or synergistic interactions of these factors. C. gigas are grown intertidally and are exposed to the air (emersed) for hours at a time. These organisms can experience extreme changes in temperature during the course of a day. An oyster closed during emersion depletes the oxygen stores to near zero within the shell and builds up CO₂ causing a decrease in tissue pH. The focus of this study is to determine the respiratory (pH, Po₂, Pco₂ and total CO₂) and immune responses of oysters exposed to air at normal seasonal temperatures, and to determine whether these stresses associated with emersion inhibit the immune system of the oyster and contribute to the summer mortalities. The respiratory variables of the hemolymph of oysters submerged at 18 °C (pH = 7.52 ± 0.04 S.E.M., Po₂ = 7.09 ± 0.53 S.E.M. kPa and Pco₂ = 0.20 ± 0.03 S.E.M. kPa) varied significantly from oysters emersed for four hours at 22°C (pH = 7.11 ± 0.03 S.E.M., Po₂ = 3.83 ± 0.15 S.E.M. kPa, Pco₂ = 0.36 ± 0.03 S.E.M. kPa) and those emersed for four hours at 30 °C (pH = 6.84 ± 0.02 S.E.M., Po₂ = 3.10 ± 0.12 S.E.M. kPa, Pco₂ = 1.31 ± 0.06 S.E.M. kPa). The ability of hemocytes to kill the bacterium Vibrio campbellii was assessed using an in vitro assay to generate a killing index. There was no significant difference in the killing index between pH treatment groups (p = 0.856): at pH 7.6 killing index = 50.2% ± 2.33 S.E.M., at pH 6.6 killing index = 52.3% ± 3.67 S.E.M.. Temperature was the only factor to significantly affect the killing indices among temperature and oxygen treatment groups. The killing index was lowest (29.3% ± 3.25 S.E.M.) at 30 °C and 7% oxygen, simulating in vivo oxygen pressure in well-aerated conditions and 30 °C and 3% oxygen, simulating in vivo oxygen pressure in hypoxia (30.5% ± 3.25 S.E.M.), compared with the index in 7% oxygen at low temperature (18 °C) (44.4% ± 4.50 S.E.M.) or compared with low oxygen (3%) at low temperature (18 °C) (39.7% ± 2.51 S.E.M.). The seasonal and diurnal rise in temperature may, therefore, be an important factor contributing to summer mortalities of C. gigas.     

Phenology of sexual reproduction in the common coral reef sponge,Carteriospongia foliascens

Understanding processes that contribute to population maintenance is critical to the management and conservation of species. Despite this, very little is currently known about the reproductive biology of Great Barrier Reef (GBR) sponge species. Here, we established reproductive parameters including mode of sexuality and development, seasonality, sex ratios, gametogenesis, reproductive output, and size at sexual maturity for the common phototrophic intertidal sponge, Carteriospongia foliascens, in the central GBR over two reproductive cycles. A population sexual productivity index (PoSPi) integrating key reproductive parameters was formulated to compare population larval supply over time. This study shows that C. foliascens is reproductive all year round, gonochoric and viviparous, with larvae developing asynchronously throughout the mesohyl. The influence of environmental parameters relevant to C. foliascens reproduction [i.e., sea surface temperature (SST), photoperiod, and rainfall] was also examined, and SST was found to have the most significant effect on phenology. C. foliascens reproduction exhibited annual mono-cyclic patterns closely resembling SST fluctuations. Reproductive output was depressed at low SST (<23 °C) and increased at temperatures above 23 °C. Peak sperm release occurred at temperatures above 25 °C, while peak larval release occurred during the annual temperature maxima (>28 °C). A twofold increase in maximum larval production (PoSPi) in C. foliascens was observed in the second reproductive cycle, following a depressed PoSPi in the first cycle. This reduction in PoSPi in the first reproductive cycle was associated with elevated SST and rainfall, coinciding with one of the strongest La Niña events on record.     

The effect of spring water on the growth of a submerged macrophyte Egeria densa

We elucidated the effect of spring water on the growth of Egeria densa Planch., a widespread submerged macrophyte in Japan. We observed the longitudinal distributions of physical (water temperature, particle diameter of the bed sediment, sediment layer thickness, etc.), chemical [pH, dissolved oxygen (DO), dissolved inorganic carbon (DIC), phosphate (PO₄-P), total nitrogen (TN), and total phosphorus (TP) content of the sediment, etc.], and biological (species composition, biomass, and growth rate) factors related to E. densa in the Kurohashi River, a spring-fed stream flowing into the Lake Biwa. It was found that E. densa growth rate from summer to autumn was negatively correlated to pH and DO, which implies that the low pH spring water increases the growth rate of the species. The growth rate was also positively correlated to the free carbon dioxide (CO₂) concentration (r = 0.67, p = 0.02). These results indicate that the low pH spring water increases E. densa growth rate by affecting free CO₂ concentration in water.     

Sclareol modulates the Treg intra-tumoral infiltrated cell and inhibits tumor growth in vivo

A regulatory or suppressor T cell is functionally defined as a T cell that inhibits an immune response by influencing the activity of another cell type. On the other hand, Th1 cells express IFN-γ and mediate cellular immunity.Sclareol exhibits growth inhibition and cytotoxic activity against a variety of human cancer cell lines. In the first set of experiments, Sclareol was isolated from the plant Salvia sclarea and our study assessed the immuno-therapeutic effectiveness of Sclareol by direct intra-tumoral injection. Secondly, several immunological parameters such as splenocytes proliferation, intra-tumor CD4⁺CD25⁺Foxp3⁺ Treg cells, IFN-γ and IL-4 secretion and tumor size were assessed to evaluate the anti-tumoral immune response. By all means, the findings confirmed that the activity of Sclareol could reduce the tumor growth in vivo against breast cancer.     

Experimentally induced stress,oxidative load and changes in immunity in a tropical wild bird,Perdicula asiatica: involvement of melatonin and glucocorticoid receptors

Throughout the year, birds encounter various environmental challenges such as extreme temperatures, rainfall and shortage of food. Here we report on the effect of stress on the general immunity of wild birds as measured by several assays including melatonin, an anti-stress hormone. We selected Perdicula asiatica, a wild tropical bird, and exposed them to experimental stressors such as water deprivation, food deprivation and immobilization, i.e., stressors that they would encounter in a natural environment. We measured the oxidative load in the spleen in terms of superoxide dismutase (SOD), catalase activity and thiobarbituric acid-reactive substance (TBARS) levels. The immune status was judged by total leukocyte count (TLC), heterophil/lymphocyte ratios (H/L) and percent stimulation ratio of splenocytes (%SR). The peripheral levels of melatonin and corticosterone were also determined and correlated with the expression of melatonin (Mel_1a/Mel_1b) and glucocorticoid receptors. Our results showed a significant (p < 0.05) decrease in splenic SOD and catalase activity, while a significant (p < 0.05) increase in TBARS and a corticosterone level was observed. Stressful conditions also decreased the immune status as reflected by the low values of H/L ratios, TLC and %SR. In contrast, melatonin pretreatment significantly (p < 0.05) reduced the oxidative stress and improved the immune parameters when compared to untreated control birds. This suggests that melatonin prevents/alleviates oxidative damage and suppresses the immune status induced by stressful conditions via its membrane receptor expression (Mel_1a and Mel_1b) in P. asiatica.