Epidemiological investigation of Cryptosporidium in children with diarrhea in middle Inner Mongolia, China.

Cryptosporidia (Cryptosporidium) is a protozoan that is widely parasitic in the intestinal cells of humans and animals, and it is also an important zoonotic parasite. However, there is no epidemiological investigation on Cryptosporidium spp. infection in infants with diarrhea of Inner Mongolia, the largest livestock region in China. To investigate the prevalence of Cryptosporidium, 2435 fresh fecal samples were collected from children with diarrhea in Inner Mongolia Maternal and Child Health Care Hospital. Molecular characterization of Cryptosporidium was carried out based on its 18S rRNA and gp60 gene sequences. The overall prevalence was 12.85% (313/2435), and in Hohhot (12.15%), it was lower than that in the surrounding city (14.87%) (P < 0.05). Moreover, Cryptosporidium was detected in different seasons and sexes. Concerning the age of children with diarrhea, the prevalence of those age groups between 0 and 1 was obviously lower than others, and there were significant differences in the prevalence at different ages (P < 0.001). Analysis of the 18S rRNA gene sequence revealed that all the positive samples were Cryptosporidium parvum, and there were 5 subtypes (IIdA23G3, IIdA24G3, IIdA24G4, IIdA25G3, and IIdA25G4). To the best of our knowledge, the above subtypes have not been reported. Our results provide a relevant basis for control and education on food safety and foodborne illness prevention.

Study on semi-bionic extraction of Astragalus polysaccharide and its anti-aging activity in vivo.

Astragalus membranaceus (A. membranaceus) is a homologous plant with high medicinal and edible value. Therefore, the extraction methods of Astragalus polysaccharide (APS) have attracted the attention of many research groups, but the yield of the active components is still not high. The aim of this study was to extract APS by a semi-bionic extraction method, optimize the extraction process, and evaluate the anti-aging activities of APS in vivo. The results showed that the APS yield was 18.23% when extracted by the semi-bionic extraction method. Anti-aging evaluation in rats showed that APS extracted by this method significantly decreased the malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity to cope with D-galactose-induced aging. Serum metabolomic analysis indicated that a total of 48 potential biomarkers showed significant differences, mainly involving 5 metabolic pathways. These altered metabolic pathways were mainly related to energy metabolism, amino acid metabolism, and lipid metabolism. These results indicated that the semi-bionic extraction method can effectively improve the yield of APS, and the extracted APS exhibited anti-aging activity in rats. Our study provided a novel and effective method to extract APS and indicated that APS can be used as functional food and natural medicine to delay aging and prevent its complications.

Differences in Toxoplasma gondii distribution in different muscle and viscera of naturally infected sheep.

Toxoplasma gondii (T. gondii) is a zoonotic parasite that can cause serious pathology in intermediate hosts such as humans and animals. Eating undercooked or raw meat is the most important route of infection by T. gondii. Sheep are an important source of meat worldwide, and they are also susceptible to T. gondii. Mutton infected with T. gondii poses a serious threat to the food safety of consumers. At present, studies have mainly focused on the infection ratio of T. gondii in livestock; however, systematic studies have not been performed on differences in the distribution of this parasite in different muscle and viscera tissues of animals. In this study, the differences in the distribution of T. gondii in naturally infected Small-tailed Han sheep was studied. By amplifying the B1 gene of the parasite via real-time fluorescence quantification PCR (RT‒qPCR), we found that the parasite burden of T. gondii differed among different parts of the sheep, with the highest burden observed in the heart among the viscera and the external ridge among the muscle. The relative expression was ranked from high to low in our study as follows: heart, spleen, external ridge, tenderloin, lung, liver, kidney, neck meat, forelegs, cucumber strips, hind leg, lamb belly, and lamb chops. This study provided important guidance for monitoring the food safety of mutton products.

Detection of Respiratory Events during Sleep Based on Fusion Analysis and Entropy Features of Cardiopulmonary Signals.

Sleep apnea hypopnea syndrome (SAHS) is a common sleep disorder with a high prevalence. The apnea hypopnea index (AHI) is an important indicator used to diagnose the severity of SAHS disorders. The calculation of the AHI is based on the accurate identification of various types of sleep respiratory events. In this paper, we proposed an automatic detection algorithm for respiratory events during sleep. In addition to the accurate recognition of normal breathing, hypopnea and apnea events using heart rate variability (HRV), entropy and other manual features, we also presented a fusion of ribcage and abdomen movement data combined with the long short-term memory (LSTM) framework to achieve the distinction between obstructive and central apnea events. While only using electrocardiogram (ECG) features, the accuracy, precision, sensitivity, and F1 score of the XGBoost model are 0.877, 0.877, 0.876, and 0.876, respectively, demonstrating that it performs better than other models. Moreover, the accuracy, sensitivity, and F1 score of the LSTM model for detecting obstructive and central apnea events were 0.866, 0.867, and 0.866, respectively. The research results of this paper can be used for the automatic recognition of sleep respiratory events as well as AHI calculation of polysomnography (PSG), which provide a theoretical basis and algorithm references for out-of-hospital sleep monitoring.

Effects of cranberry powder on the diversity of microbial communities and quality characteristics of fermented sausage.

Fermented sausage is popular with many consumers because of its distinctive flavor, but the safety of it has attracted widespread attention. At present, nitrite is widely used in fermented meat products because of its ideal color and bacteriostatic effect, but nitrite can be transformed into nitrosamines, which cause strong carcinogenic effects. Therefore, it is urgent to actively explore safe and efficient nitrite substitutes. In this study, cranberry powder was selected as a natural substitute for nitrite during the production of fermented sausage due to its unique antioxidant and bacteriostatic properties. The results showed that adding an appropriate amount of cranberry powder (5 g/kg) promoted a better color of the fermented sausage and promoted the accumulation of aromatic compounds. Furthermore, Pediococcus and Staphylococcus became the dominant species, accounting for more than 90% in all samples. According to the Pearson correlation analysis, Staphylococcus and Pediococcus had positive effects on the quality characteristics of fermented sausage products. This study provided the latest information on the application of cranberry powder as a natural substitute for nitrite in the process of manufacturing fermented sausage, and it also introduced an advanced solution to improve the quality characteristics and safety of fermented sausage products during processing.

Lactobacillus improves meat quality in Sunit sheep by affecting mitochondrial biogenesis through the AMPK pathway.

Sunit sheep are famous for their high meat quality, but the meat quality of them has declined due to the change in feeding methods. Lactobacillus has a variety of probiotic effects and is widely used in animal diets to optimize meat quality. This study aimed to investigate the effect of dietary supplementation with different levels of Lactobacillus on meat quality. A total of 24 3-month-old Sunit sheep with an average body weight of 19.03 ± 3.67 kg were randomly divided into control (C), 1% (L1), 2% (L2), and 3% Lactobacillus groups (L3), with 6 sheep in each group. Myofiber characteristics, meat quality, and metabolic enzyme activity were detected. Moreover, the regulatory mechanism of Lactobacillus on meat quality was explored by using Western blotting and real-time Quantitative polymerase chain reaction (RT-qPCR). The results showed that dietary addition of Lactobacillus decreased LDH activity in the Biceps femoris of Sunit sheep (P < 0.05). Compared to the other groups, the 1% Lactobacillus group showed the conversion of myofibers from the glycolytic to the oxidative type, and the increasing b* values (P < 0.05), decreasing shear force and cooking loss of meat (P < 0.05) and the relative gene and protein expression levels of AMPK, PGC-1α, NRF1, TFAM, and COX IV (P < 0.05) in the Biceps femoris were also increased in the 1% Lactobacillus group. Therefore, the addition of Lactobacillus to the diet of Sunit sheep could regulate the AMPK signaling pathway to promote myofiber type conversion, which improves meat quality. This study provided a theoretical and data basis for improving the meat quality of sheep and supplied a novel way of applying Lactobacillus.

Study on the effect of koumiss on reactivation of Toxoplasma gondii infection.

Toxoplasma gondii is an obligate intracellular parasite that infects nucleated cells of all warm-blooded animals, and most patients have latent infections. The latent infection will be reactivated in the immunocompromised or immunocompromised individuals, which will lead to severe toxoplasmosis. At present, less research has been focused on the reactivation of T. gondii infection. Koumiss is a kind of fermented milk made from fresh mare's milk through natural fermentation that can be applied to clinical and rehabilitation medicine to mitigate the development of various diseases due to its unique functional characteristics. In this study, we explored the antagonistic effect of koumiss on reactivation of T. gondii infection. Mice were treated with dexamethasone to establish a reactivation model after infection with T. gondii and then treated with koumiss. The survival rate, SHIRPA test, serum cytokine levels, organ parasite burden and intestinal microbiota were measured, respectively. Our results showed that koumiss treatment improved the clinical symptoms of mice, significantly reduced the organ parasite burden of mice, and improved the composition and structure of intestinal flora. This study provides new evidence for the alleviation and treatment of toxoplasmosis and provides a novel idea for the development and utilization of koumiss.

Study on the antagonistic effects of koumiss on Toxoplasma gondii infection in mice.

Toxoplasma gondii is an important food-borne zoonotic parasite, and approximately one-third of people worldwide are positive for T. gondii antibodies. To date, there are no specific drugs or vaccines against T. gondii. Therefore, developing a new safe and effective method has become a new trend in treating toxoplasmosis. Koumiss is rich in probiotics and many components that can alleviate the clinical symptoms of many diseases via the functional characteristics of koumiss and its regulation of intestinal flora. To investigate the antagonistic effect of koumiss on T. gondii infection, the model of acute and chronic T. gondii infection was established in this study. The survival rate, SHIRPA score, serum cytokine levels, brain cyst counts, ß-amyloid deposition and intestinal flora changes were measured after koumiss feeding. The results showed that the clinical symptoms of mice were improved at 6 dpi and that the SHIRPA score decreased after koumiss feeding (P < 0.05). At the same time, the levels of IL-4, IFN-γ and TNF-α decreased (P < 0.001, P < 0.001, P < 0.01). There was no significant difference of survival rate between koumiss treatment and the other groups. Surprisingly, the results of chronic infection models showed that koumiss could significantly reduce the number of brain cysts in mice (P < 0.05), improve ß-amyloid deposition in the hippocampus (P < 0.01) and decrease the levels of IFN-γ and TNF-α (P < 0.01, P < 0.05). Moreover, koumiss could influence the gut microbiota function in resisting T. gondii infection. In conclusion, koumiss had a significant effect on chronic T. gondii infection in mice and could improve the relevant indicators of acute T. gondii infection in mice. The research provides new evidence for the development of safe and effective anti-T. gondii methods, as well as a theoretical basis and data support for the use of probiotics against T. gondii infection and broadened thoughts for the development and utilization of koumiss.

Effect of collagen casing on the quality characteristics of fermented sausage.

OBJECTIVE: Fermented sausage is popular all over the world for its rich nutrition and unique flavor. Sausage casing is one of the key factors affecting the quality of fermented sausage. However, there is little information involved in this field. METHODS: In this study, collagen casings were used as a wrapping material, and natural casings (pig casings) were used as a control. The effects of the two types of casings on biogenic amine content and other quality characteristics of fermented sausage were analyzed with increasing the storage time. RESULTS: The results showed that with storage time increasing, the hardness and gumminess of fermented sausage in collagen casing (CC) group were higher than those in pig casing (PC) group (P<0.05), while the elasticity in CC group was lower than that in PC group (P<0.05). In the processing and storage period, there was no significant difference in the type and content of flavor substances between the two groups. More importantly, the contents of tryptamine, putrescine, cadaverine, histamine, tyramine and phenyethylamine in fermented sausage of CC group were lower than those in PC group (P<0.05). CONCLUSION: In conclusion, this study revealed that CC could improve the quality characteristics of fermented sausage and reduce the content of biogenic amines in fermented sausage, which provides a theoretical basis for the choice of casings in industrial production in the future.

Study on the effect of koumiss on the intestinal microbiota of mice infected with Toxoplasma gondii.

Toxoplasma gondii is a worldwide food-borne parasite that can infect almost all warm-blooded animals, including humans. To date, there are no effective drugs to prevent or eradicate T. gondii infection. Recent studies have shown that probiotics could influence the relationship between the microbiota and parasites in the host. Koumiss has been used to treat many diseases based on its probiotic diversity. Therefore, we explored the effect of koumiss on T. gondii infection via its effect on the host intestinal microbiota. BALB/c mice were infected with T. gondii and treated with PBS, koumiss and mares' milk. Brain cysts were counted, and long-term changes in the microbiota and the effect of koumiss on gut microbiota were investigated with high-throughput sequencing technology. The results suggested that koumiss treatment significantly decreased the cyst counts in the brain (P < 0.05). Moreover, T. gondii infection changed the microbiota composition, and koumiss treatment increased the relative abundance of Lachnospiraceae and Akkermansia muciniphila, which were associated with preventing T. gondii infection. Moreover, koumiss could inhibit or ameliorate T. gondii infection by increasing the abundance of certain bacteria that control unique metabolic pathways. The study not only established a close interaction among the host, intracellular pathogens and intestinal microbiota but also provided a novel focus for drug development to prevent and eradicate T. gondii infection.

Skeleton-Based Abnormal Behavior Detection Using Secure Partitioned Convolutional Neural Network Model.

Theabnormal behavior detection is the vital for evaluation of daily-life health status of the patient with cognitive impairment. Previous studies about abnormal behavior detection indicate that convolution neural network (CNN)-based computer vision owns the high robustness and accuracy for detection. However, executing CNN model on the cloud possible incurs a privacy disclosure problem during data transmission, and the high computation overhead makes difficult to execute the model on edge-end IoT devices with a well real-time performance. In this paper, we realize a skeleton-based abnormal behavior detection, and propose a secure partitioned CNN model (SP-CNN) to extract human skeleton keypoints and achieve safely collaborative computing by deploying different CNN model layers on the cloud and the IoT device. Because, the data outputted from the IoT device are processed by the several CNN layers instead of transmitting the sensitive video data, objectively it reduces the risk of privacy disclosure. Moreover, we also design an encryption method based on channel state information (CSI) to guarantee the sensitive data security. At last, we apply SP-CNN in abnormal behavior detection to evaluate its effectiveness. The experiment results illustrate that the efficiency of the abnormal behavior detection based on SP-CNN is at least 33.2% higher than the state-of-the-art methods, and its detection accuracy arrives to 97.54%.

An Investigation of the Relationship between Cyniclomyces guttulatus and Rabbit Diarrhoea.

Cyniclomyces guttulatus is usually recognised as an inhabitant of the gastrointestinal (GI) tract in rabbits. However, large numbers of C. guttulatus are often detected in the faeces of diarrhoeic rabbits. The relationship of C. guttulatus with rabbit diarrhoea needs to be clearly identified. In this study, a C. guttulatus Zhejiang strain was isolated from a New Zealand White rabbit with severe diarrhoea and then inoculated into SPF New Zealand white rabbits alone or co-inoculated with Eimeriaintestinalis, another kind of pathogen in rabbits. Our results showed that the optimal culture medium pH and temperature for this yeast were pH 4.5 and 40-42 °C, respectively. The sequence lengths of the 18S and 26S ribosomal DNA fragments were 1559 bp and 632 bp, respectively, and showed 99.8% homology with the 18S ribosomal sequence of the NRRL Y-17561 isolate from dogs and 100% homology with the 26S ribosomal sequence of DPA-CGR1 and CGDPA-GP1 isolates from rabbits and guinea pigs, respectively. In animal experiments, the C. guttulatus Zhejiang strain was not pathogenic to healthy rabbits, even when 1 × 108 vegetative cells were used per rabbit. Surprisingly, rabbits inoculated with yeast showed a slightly better body weight gain and higher food intake. However, SPF rabbits co-inoculated with C. guttulatus and E. intestinalis developed more severe coccidiosis than rabbits inoculated with C. guttulatus or E. intestinalis alone. In addition, we surveyed the prevalence of C. guttulatus in rabbits and found that the positive rate was 83% in Zhejiang Province. In summary, the results indicated that C. guttulatus alone is not pathogenic to healthy rabbits, although might be an opportunistic pathogen when the digestive tract is damaged by other pathogens, such as coccidia.

Potential linkage between Toxoplasma gondii infection and physical education scores of college students.

OBJECTIVE: Toxoplasma gondii is a worldwide protozoan parasite that could infect virtually all warm-blooded animals, including humans. Our study aimed to investigate the prevalence of T. gondii infection in college students at Anhui province, China and to assess risk factors for T. gondii infection in college students. Moreover, growing studies demonstrated the association between T. gondii infection and host behavioral changes. We also studied the linkage between T. gondii and physical education (PE) scores of college students. METHODS: A total of 2704 serum samples of medical school students attending physical education lessons were collected from September 2017 to September 2019 and evaluated for T. gondii IgG antibodies using an enzyme-linked immunosorbent assay (ELISA). Questionnaires and statistical analysis were used to determine the risk factors for T. gondii infection. We also analysed PE scores of T. gondii -infected students and T. gondii-uninfected students. RESULTS: The overall seroprevalence of T. gondii was 11.5%. The main risk factors related to T. gondii infection in college students were cat in the household and gardening or agriculture activity. Furthermore, in the basketball group and the soccer group, scores of T. gondii seropositive students were significantly higher than those of seronegative students, while in other sports there was no difference between scores of T. gondii-infected students and T. gondii uninfected students. CONCLUSION: This is the first report of T. gondii seroprevalence in college students in Anhui province, China.

Exogenous nitric oxide stimulates early egress of Eimeria tenella sporozoites from primary chicken kidney cells in vitro.

Egress plays a vital role in the life cycle of apicomplexan parasites including Eimeria tenella, which has been attracting attention from various research groups. Many recent studies have focused on early egress induced by immune molecules to develop a new method of apicomplexan parasite elimination. In this study, we investigated whether nitric oxide (NO), an immune molecule produced by different types of cells in response to cytokine stimulation, could induce early egress of eimerian sporozoites in vitro. Eimeria tenella sporozoites were extracted and cultured in primary chicken kidney cells. The number of sporozoites egressed from infected cells was analyzed by flow cytometry after treatment with NO released by sodium nitroferricyanide (II) dihydrate. The results showed that exogenous NO stimulated the rapid egress of E. tenella sporozoites from primary chicken kidney cells before replication of the parasite. We also found that egress was dependent on intra-parasitic calcium ion (Ca2+) levels and no damage occurred to host cells after egress. The virulence of egressed sporozoites was significantly lower than that of fresh sporozoites. The results of this study contribute to a novel field examining the interactions between apicomplexan parasites and their host cells, as well as that of the clearance of intracellular pathogens by the host immune system.

TITLE: L'oxyde nitrique exogène stimule in vitro la sortie précoce des sporozoïtes d'Eimeria tenella des cellules primaires de rein de poulet. ABSTRACT: La sortie des cellules joue un rôle vital dans le cycle de vie des parasites Apicomplexa, y compris Eimeria tenella, ce qui a attiré l'attention de plusieurs groupes de recherche. De nombreuses études récentes se sont concentrées sur la sortie précoce induite par des molécules immunitaires, pour développer une nouvelle méthode d'élimination des parasites Apicomplexa. Dans cette étude, nous avons examiné si l'oxyde nitrique (NO), une molécule immunitaire produite par différents types de cellules en réponse à la stimulation des cytokines, pouvait induire in vitro une sortie précoce des sporozoïtes des Eimeria. Les sporozoïtes d'E. tenella ont été extraits et cultivés dans des cellules primaires de rein de poulet. Le nombre de sporozoïtes sortant des cellules infectées a été analysé par cytométrie en flux après traitement avec du NO libéré par le nitroferricyanure de sodium (II) dihydraté. Les résultats ont montré que le NO exogène stimulait la sortie rapide des sporozoïtes d'E. tenella des cellules primaires de rein de poulet avant la réplication du parasite. Nous avons également constaté que la sortie dépendait des niveaux intra-parasitaires d'ions calcium (Ca2+) et qu'aucun dommage n'est survenu aux cellules hôtes après la sortie. La virulence des sporozoïtes sortis était significativement inférieure à celle des sporozoïtes frais. Les résultats de cette étude contribuent à un nouveau domaine d'étude des interactions entre les parasites Apicomplexa et leurs cellules hôtes, ainsi qu'à celui relatif à l'élimination des pathogènes intracellulaires par le système immunitaire de l'hôte.

Seroprevalence of Toxoplasma gondii infection in sheep in Inner Mongolia Province, China.

Toxoplasma gondii is an important zoonotic parasite that can infect almost all warm-blooded animals, including humans, and infection may result in many adverse effects on animal husbandry production. Animal husbandry in Inner Mongolia is well developed, but data on T. gondii infection in sheep are lacking. In this study, we determined the seroprevalence and risk factors associated with the seroprevalence of T. gondii using an indirect enzyme-linked immunosorbent assay (ELISA) test. A total of 1853 serum samples were collected from 29 counties of Xilin Gol League (n = 624), Hohhot City (n = 225), Ordos City (n = 158), Wulanchabu City (n = 144), Bayan Nur City (n = 114) and Hulunbeir City (n = 588). The overall seroprevalence of T. gondii was 15.43%. Risk factor analysis showed that seroprevalence was higher in sheep ≥12 months of age (21.85%) than that in sheep <12 months of age (10.20%) (p < 0.01). Seroprevalence was higher in male sheep (18.76%) than females (12.80%) (p < 0.01). Barn-feeding sheep (23.13%) had higher prevalence than grazing sheep (10.94%) (p < 0.01). The seroprevalence was significantly different in different districts (p < 0.01). This study shows that sheep are exposed to T. gondii in Inner Mongolia, and provides a data reference for public health and disease control.

TITLE: Séroprévalence de l'infection par Toxoplasma gondii des moutons dans la province de Mongolie intérieure, Chine. ABSTRACT: Toxoplasma gondii est un parasite zoonotique important qui peut infecter presque tous les animaux à sang chaud, y compris les humains, et son infection peut entraîner de nombreux effets néfastes sur la production animale. L'élevage de Mongolie intérieure est développé, mais les données sur l'infection des moutons par T. gondii manquent. Dans cette étude, nous avons déterminé la séroprévalence et les facteurs de risque associés à la séroprévalence de T. gondii en utilisant un test immuno-enzymatique indirect (ELISA). Un total de 1853 échantillons de sérum ont été prélevés dans vingt-neuf comtés de la Ligue Xilin Gol (n = 624), Hohhot City (n = 225), Ordos City (n = 158), Wulanchabu City (n = 144), Bayan Nur City (n = 114) et la ville de Hulunbeir (n = 588). La séroprévalence globale de T. gondii était de 15,43 %. L'analyse des facteurs de risque a montré que le taux d'infection était plus élevé chez les ovins ≥ 12 mois (21,85 %) que chez les ovins <12 mois (10,20 %) (p < 0,01). Les moutons mâles (18,76 %) avaient une séroprévalence plus élevée que les femelles (12,80 %) (p < 0,01). Les moutons nourris à l'étable (23,13 %) avaient une séroprévalence plus élevée que ceux au pâturage (10,94 %) (p < 0,01). La séroprévalence était significativement différente entre les différents districts (p < 0,01). L'étude a montré que les moutons étaient exposés à T. gondii en Mongolie intérieure et a fourni une référence de données pour la santé publique et la lutte contre les maladies.

A Method of FPGA-Based Extraction of High-Precision Time-Difference Information and Implementation of Its Hardware Circuit.

Abstract: The positioning technology to find shallow underground vibration sources based on a wireless sensor network is receiving great interest in the field of underground position measurements. The slow peaking and strong multi-waveform aliasing typical of the underground vibration signal result in a low extraction accuracy of the time difference and a poor source-positioning accuracy. At the same time, the transmission of large amounts of sensor data and the host computer's slow data processing speed make locating a source a slow process. To address the above problems, this paper proposes a method for high-precision time-difference measurements in near-field blasting and a method for its hardware implementation. First, based on the broadband that is typical of blast waves, the peak frequency of the P-wave was obtained in the time-frequency domain, taking advantage of the difference in the propagation speed of the P-wave, S-wave, and the surface wave. Second, the phase difference between two sensor nodes was found by means of a spectral decomposition and a correlation measurement. Third, the phase ambiguity was eliminated using the time interval of the first break and the dynamic characteristics of the sensors. Finally, following a top-down design idea, the hardware system was designed using Field Programmable Gate Array(FPGA). Verification, using both numerical simulations and experiments, suggested that compared with generalized cross-correlation-based time-difference measurement methods, the proposed method produced a higher time-difference resolution and accuracy. Compared with the traditional host computer post-position positioning method, the proposed method was significantly quicker. It can be seen that the proposed method provides a new solution for solving high-precision and quick source-location problems, and affords a technical means for developing high-speed, real-time source-location instruments.

Calcium-dependent microneme protein discharge and in vitro egress of Eimeria tenella sporozoites.

Egress is a vital step in the endogenous development of apicomplexan parasites, as it assures the parasites exit from consumed host cells and entry into fresh ones. However, little information has previously been reported on this step of Eimeria spp. In this study, we investigated in vitro egress of Eimeria tenella sporozoites triggered by acetaldehyde. We found that addition of exogenous acetaldehyde induces egress of sporozoites from primary chicken kidney cells (PCKs) and stimulate secretion of E. tenella microneme 2 protein (EtMic 2). Moreover, by using cellular calcium inhibitors, we further proved that these processes were dependent on the intracellular calcium of the parasites. Our findings provide clues to the study of interaction between eimerian parasites and their hosts.

In vitro observation of the stage conversion of transgenic Toxoplasma gondii RH strain expressing dual fluorescent proteins.

Toxoplasma gondii converts from tachyzoites to bradyzoites after acute infection and thus survives the attack of the host immune responses. In this study, we observed the conversion of tachyzoites to bradyzoites in cell cultures using a transgenic T. gondii RH strain. The transgenic parasites continuously express yellow fluorescent protein (YFP) but only express red fluorescent protein (RFP) at the bradyzoite stage. Red fluorescent bradyzoite-containing cysts were found in transgenic parasite infected cells cultured with atmospheric CO2 supply, indicating the successful induction of the stage conversion. In cell culture with alkalic medium (pH 8.1) and atmospheric CO2 supply, only part of the YFP-expressing parasites in a cyst express RFP marker, suggesting the asynchronous development of T. gondii in vitro. This study provides a possibility for further studies of the gene expression profile during stage conversion and the genes involved.

Nitric oxide stimulates early egress of Toxoplasma gondii tachyzoites from Human foreskin fibroblast cells.

BACKGROUND: Egress is a vital step in the life cycle of Toxoplasma gondii which attracts attentions of many groups. Previous studies have shown that exogenous nitric oxide (NO) stimulates the early egress of T. gondii from infected peritoneal macrophages, a kind of immune cells. However, because Toxoplasma forms cysts in brain and muscle tissues, the development of autonomous immunity in non-immune cells is vital for limiting parasite burden and cyst formation. Therefore, we attempted to investigate whether exogenous NO could induce the early egress of T. gondii from infected non-immune cells. METHODS: T. gondii tachyzoites were cultured in human foreskin fibroblast (HFF) cells and were then treated with NO released by sodium nitroferricyanide (III) dihydrate (SNP). The egressed parasites were analysed by flow cytometry. RESULTS: The results showed that NO induced the early egress of parasites from HFF cells before completing their intracellular life cycles. We also found that the occurrence of egress was dependent on intracellular calcium (Ca(2+)) levels and the mobility of the parasite. Compared with freshly isolated tachyzoites, the developmental ability and virulence of egressed tachyzoites presented no difference. CONCLUSIONS: Taken together, our findings demonstrate a novel assay for the analysis of egress signalling mechanisms and an avenue of parasite clearance by hosts of T. gondii.

Ethanol and isopropanol trigger rapid egress of intracellular Eimeria tenella sporozoites.

Egress from host cells is a vital step of the intracellular life cycle of apicomplexan parasites such as Toxoplasma gondii. This phenomenon has attracted attentions from many research groups. Previous studies have shown that ethanol could stimulate the release of microneme proteins by elevating intracellular Ca(2+) concentration of T. gondii, resulting in the parasite egress from host cells. However, little information about egress is known on Eimeria species, the causative agent of coccidiosis in poultry and livestock. In this report, we studied the effect of ethanol and isopropanol on the egress of eimerian parasites. Eimeria tenella sporozoites cultured in primary chicken kidney cells were treated with ethanol and isopropanol, then the egressed parasites were analyzed. Ethanol and isopropanol could induce the rapid egress of E. tenella sporozoites from host cells. No substantial damage was found in parasite-egressed host cells. Compared to the freshly isolated sporozoites, the re-invading ability and reproductivity of the egressed parasites significantly decreased by 43.4 and 44.1 % individually. We also found that fewer sporozoites egressed from host cells when the parasites developed for a longer time before the alcohol treatment. These results demonstrate an in vitro egress mode different from that of T. gondii, facilitating the deciphering of the mechanisms of egress of eimerian parasites.