Forward genetic analysis of monensin and diclazuril resistance in Eimeria tenella.

Worldwide distributed coccidiosis is caused by infection of both Eimeria species and Cystoisospora in the host intestine and causes huge economic losses to the livestock industry, especially the poultry industry. The control of such diseases relies mainly on chemoprophylaxis with anticoccidials, which has led to a very common drug resistance in this field. However, the genetic mechanisms underlying resistance to many anticoccidial drugs remain unknown. In this study, strains of E. tenella resistant to 250 mg/kg monensin were generated and characterized. Forward genetic approaches based on pooled genome sequencing, including experimental evolution and linkage group selection, were used to locate candidate targets responsible for resistance to monensin and diclazuril in E. tenella. A total of 16 nonsynonymous mutants in protein-coding genes were identified in monensin-resistant strains, and two genomic regions with strong selection signals were also detected in diclazuril-resistant strains. Our study reveals the genetic characterization of the experimental evolution and linkage group selection in Eimeria species, and also provides important information that contributes to the understanding of the molecular mechanism of drug resistance in coccidia.

Atractylodes-I Overcomes the Oxidative Stress-induced Colonic Mucosal Epithelial Cells Dysfunction to Prevent Irritable Bowel Syndrome Via Modulating the miR-34a-5p-LDHA Signaling Pathway.

BACKGROUND: Irritable bowel syndrome (IBS) is a known brain-gut disorder. Currently, the molecular and cellular mechanisms of IBS remain unclear. Atractylenolide-I (ATL-I) is a majorly bioactive component extracted from Rhizoma Atractylodes Macrocephalae. METHODS: Studies have revealed that ATL-I functioned as an anti-tumor drug in various cancers. However, the effects and molecular mechanisms of ATL-I on the pathological processes of colonic mucosal epithelial cells (CMECs) during IBS remain unclear. This study reports ATL-I effectively alleviated the oxidative stress-induced colonic mucosal epithelial cell dysfunction. In colonic mucosal tissues from IBS patients, we detected upregulated miR-34a-5p and suppressed glucose metabolism enzyme expressions. Under H2O2 treatment which mimics in vitro oxidative stress, miR-34a-5p was induced and glucose metabolism was inhibited in the colon mucosal epithelial cell line, NCM460. Meanwhile, ATL-I treatment effectively overcame the oxidative stress-induced miR-34a- 5p expression and glucose metabolism in NCM460 cells. RESULT: By bioinformatics analysis, Western blot and luciferase assay, we illustrated that miR-34a-5p directly targeted the 3'UTR region of glucose metabolism key enzyme, lactate dehydrogenase-A (LDHA) in colonic mucosal epithelial cells. Rescue experiments validated that miR-34a-5p inhibited glucose metabolism by targeting LDHA. Finally, we demonstrated that ATL-I treatment reversed the miR-34a-5p-inhibited glucose metabolism and -exacerbated colonic mucosal epithelial cell dysfunction under oxidative stress by modulating the miR-34a-5p-LDHA pathway. CONCLUSION: Summarily, our study reports the roles and mechanisms of ATL-I in the oxidative stress-induced colonic mucosal epithelial cell dysfunction during IBS through regulating the miR-34a-5p-LDHA-glucose metabolism axis.

Inflammasome activation restrains the intracellular Neospora caninum proliferation in bovine macrophages.

Neospora caninum is an intracellular parasite that causes neosporosis in cattle. Bovine neosporosis is considered a major cause of bovine abortion worldwide. Rapid replication of N. caninum tachyzoites within host cells is responsible for the acute phase of N. caninum infection. Evidence shows that the host immune response plays an essential role in recognizing and regulating the replication of invading pathogens. Nucleotide-binding oligomerization domain receptors (NLRs) are a class of cytoplasmic sensors that can sense pathogens and induce the formation of the inflammasome complex. Activation of the inflammasome promotes restriction of microbial replication. Our previous study revealed NLRP3 inflammasome activation in N. caninum-infected murine macrophages. However, the role of inflammasome activity in N. caninum-infected bovine cells is unknown. To address this question, a bovine peritoneal macrophage cell line was used to investigate the role of inflammasome activation in regulating intracellular N. caninum replication. The results showed that inflammasome mediated activation of caspase-1 occurs in N. caninum-infected bovine macrophages, and caspase-1-dependent cell death was considered to be induced in N. caninum-infected bovine macrophages because N. caninum induced cell death decreased following pretreatment with zVAD-fmk and VX765. Meanwhile, the inhibition of caspase-1 in N. caninum-infected bovine macrophages led to the presence of more parasites in the parasitophorous vacuole. In contrast, inflammasome activation induced by ATP treatment in N. caninum-infected bovine macrophages contributed to the clearance of N. caninum. In addition, pyroptotic cell supernatant collected from ATP-stimulated bovine macrophages also impaired the ability of this parasite to infect new cells. In conclusion, this study is the first report on the role of the bovine inflammasome in restraining intracellular N. caninum replication and suggests that the bovine inflammasome may be a potential target for future development of drugs or vaccines against N. caninum infection in cattle.

Influence of Eimeria falciformis Infection on Gut Microbiota and Metabolic Pathways in Mice.

Coccidiosis, caused by different species of Eimeria parasites, is an economically important disease of poultry and livestock worldwide. Here we report previously unknown alterations in the gut microbes and metabolism of BALB/c mice infected with Eimeria falciformis Specifically, we observed a significant shift in the abundance of cecal bacteria and disrupted metabolism in parasitized animals. The relative abundances of Lachnospiraceae bacterium NK4A136, Ruminiclostridium, Alistipes, and Lactobacillus declined in response to E. falciformis infection, whereas Escherichia, Shigella, Helicobacter, Klebsiella, and Bacteroides were increased. Carbohydrate and amino acid metabolites in the serum samples of infected mice were significantly altered compared to naïve controls. Levels of amino acids, including asparagine, histidine, l-cysteine, tryptophan, lysine, glycine, serine, alanine, proline, ornithine, methionine, and valine, decreased on day 7 postinfection before returning to baseline on day 14. In addition, increased levels of indolelactate and mannitol and a reduced amount of oxalic acid indicated impaired carbon metabolism upon parasitic infection. These data demonstrate that intestinal coccidial infection perturbs the microbiota and disrupts carbon and nitrogen metabolism.

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.

"Self-cleaving" 2A peptide from porcine teschovirus-1 mediates cleavage of dual fluorescent proteins in transgenic Eimeria tenella.

The "self-cleaving" 2A sequence of picornavirus, which mediates ribosome-skipping events, enables the generation of two or more separate peptide products from one mRNA containing one or more "self-cleaving" 2A sequences. In this study, we introduced a single 2A sequence of porcine teschovirus-1 (P2A) linked to two fluorescent protein genes, the enhanced yellow fluorescent protein (EYFP) gene and the red fluorescent protein (RFP) gene, in a single cassette into transgenic Eimeria tenella (EtER). As expected, we obtained two separated protein molecules rather than a fused protein, although the two molecules were translated from the same mRNA carrying a single "self-cleaving" 2A sequence. Importantly, RFP led by a secretion signal was secreted into parasitophorous vacuoles, while EYFP localized mainly to the nucleus of EtER. Our results demonstrate that the "self-cleaving" 2A sequence actively mediated cleavage of polyproteins in the apicomplexan parasite E. tenella.

From the Macro to the Micro: Gel Mapping to Differentiate between Sporozoites of Two Immunologically Distinct Strains of Eimeria maxima (Strains M6 and Guelph).

Two immunologically distinct strains of E. maxima were examined in this study: the M6 strain and the Guelph strain. The differential expression between the sporozoites of the two strains of E. maxima was determined by image analysis of 100 µg of protein from each strain separated by standard one- and conventional two-dimensional polyacrylamide gel electrophoresis. In addition to differences in both molecular weight and the electrophoretic mobility, differences in the intensity of polypeptide bands for example, GS 136.4 and M6 169 were explored. Pooled gels were prepared from each strain. A representative 2D-PAGE gel spanning a non-linear pH range of 3-10 of E. maxima strain M6 consisted of approximately 694 polypeptide spots with about 67 (9.6%) of the polypeptide spots being unique relative to the other strain. E. maxima strain GS had about 696 discernable polypeptide spots with 69 spots (9.9%) that differed from those of the M6 strain. In-depth characterization of the variable polypeptide spots; unique polypeptide spots (absence or presence) and shared polypeptide spots with modifications may lead to novel vaccine target in the form of multi-component, multi-stage, multi-immunovariant strains, multi-species subunit vaccine, and diagnostic probe for E. maxima.

Interferon-Gamma Release Assay: An Effective Tool to Detect Early Toxoplasma gondii Infection in Mice.

Early diagnosis of Toxoplasma gondii infection before the formation of tissue cysts is vital for treatment, as drugs available for toxoplasmosis cannot kill bradyzoites contained in the cysts. However, current methods, such as antibody-based ELISA, are ineffective for detection of early infection. Here, we developed an interferon-gamma release assay (IGRA), measuring the IFN-γ released by T lymphocytes stimulated by Toxoplasma antigen peptides in vitro, for the detection of T. gondii infection in mice. Splenocytes isolated from infected mice were stimulated by peptides derived from dense granule proteins GRA4 and GRA6 and rhoptry protein ROP7, and released IFN-γ was measured by ELISA. Results showed that both acute and chronic infection could be detected by IGRA. More importantly, IGRA detected infection as early as the third day post infection; while serum IgM and IgG were detected 9 days and 13 days post infection, respectively. Our findings demonstrated that an IGRA-positive and ELISA-negative sample revealed an early infection, indicating the combination of IGRA and ELISA can be employed for the early diagnosis of T. gondii infection in human beings, cats and livestock.

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.

Early detection of Toxoplasma gondii-infected cats by interferon-gamma release assay.

Felines, the only definitive hosts that shed the environmentally-durable oocysts, are the key in the transmission of Toxoplasma gondii to all warm-blooded animals. They seroconvert as late as the third week and begin to shed oocysts as early as 3-8 days after being fed tissue cysts. Early detection of Toxoplasma-infected cats is crucial to evaluate Toxoplasma-contaminated environment and potential risks to public health. Moreover, it is fundamental for Toxoplasma infection control. Interferon-gamma release assay (IGRA) is a blood-based test assessing the presence of IFN-γ released by the T-lymphocytes directed against specific antigens, which is an ideal assay for early detection of Toxoplasma-infected cats. Here, cats were orally infected with the tissue cysts and blood was collected for toxoplasmic antigen stimulation, and the released IFN-γ was measured by ELISA. Results showed that Toxoplasma-infection was detected by IGRA as early as 4 days post-infection (dpi); while serum Toxoplasma IgM and IgG were detected by ELISA at 10 dpi and 14 dpi, respectively. Our findings demonstrated that IGRA-positive and ELISA-negative samples revealed an early Toxoplasma infection in cats, indicating a new strategy for the early diagnosis of Toxoplasma infection by combining IGRA and ELISA. Therefore, IGRA could emerge as a reliable diagnostic tool for the exploration of cat toxoplasmosis prevalence and its potential risks to public health.

Immunogenicity and protective efficacy of an Eimeria vaccine candidate based on Eimeria tenella immune mapped protein 1 and chicken CD40 ligand.

The CD40 ligand (CD40L) has shown potential as a powerful immunological adjuvant in various studies. Here, the efficacy of a chimeric subunit vaccine, consisting of Eimeria tenella immune mapped protein 1 (EtIMP1) and chicken CD40L, was evaluated against E. tenella infection. The recombinant EtIMP1-CD40L was purified from E. coli over-expressing this protein. Chickens were vaccinated with EtIMP1-CD40L without adjuvant or EtIMP1 with Freund's adjuvant. Immunization of chickens with EtIMP1-CD40L fusion protein resulted in stronger IFN-γ secretion and IgA response than that with only recombinant EtIMP1 with Freund's adjuvant. The clinical effect (cecal lesions, body weights gain, and oocysts shedding) of the EtIMP1-CD40L without adjuvant was also better than that of the EtIMP1 with adjuvant, as evidenced by the difference between the two groups in the oocyst output of E. tenella-challenged chickens. The results suggest that the EtIMP1-CD40L fusion protein can be used as an effective immunogen in the development of subunit vaccines against Eimeria infection.

Exploring early and late Toxoplasma gondii strain RH infection by two-dimensional immunoblots of chicken immunoglobulin G and M profiles.

Toxoplasma gondii is an intracellular apicomplexan parasite infecting warm-blooded vertebrate hosts, with only early infection stage being contained with drugs. But diagnosis differencing early and late infection was not available. In the present investigation, 2-dimensional immunobloting was used to explore early and late infections in chickens. The protein expression of T. gondii was determined by image analysis of the tachyzoites proteome separated by standard-one and conventional two-dimentional gel polyacrylamide electrophoresis (2D- PAGE). Pooled gels were prepared from tachyzoites of T. gondii. A representative gel spanning a pH range of 3-10 of the tachyzoite proteome consisted of 1306 distinct polypeptide spots. Two-dimensional electrophoresis (2-DE) combined with 2-DE immunoblotting was used to resolve and compare immunoglobulins (Igs) M & G patterns against Toxoplasma gondii strain RH (mouse virulent strain). Total tachyzoite proteins of T. gondii were separated by two-dimensional gel electrophoresis and analyzed by Western blotting for their reactivity with the 7 and 56 days post-infection (dpi) SPF chicken antisera. Different antigenic determinant patterns were detected during analysis with M and G immunoglobulins. Of the total number of polypeptide spots analyzed (1306 differentially expressed protein spots), 6.97% were identified as having shared antigenic polypeptide spots on immunoblot profiles with IgG and IgM antibodies regardless the time after infection. Furthermore, some of the immunoreactive polypeptide spots seemed to be related to the stage of infection. Interestingly, we found natural antibodies to toxoplasmic antigens, in addition to the highly conserved antigenic determinants that reacted with non-specific secondary antibody; goat anti-chicken IgG antibodies conjugated with horseradish peroxidase. In conclusion, unique reactive polypeptide spots are promising candidates for designation of molecular markers to discriminate early and late chicken infection.

Acquired adenoma of the nonpigmented ciliary epithelium: analysis of five cases.

PURPOSE: Adenoma of the non-pigmented ciliary epithelium (ANPCE) is extremely rare. The aim of this study is to present our experience in treating this rare entity and to determine the long-term surgical outcomes of local tumor resection (partial iridocyclectomy with lamellar sclerouvectomy) in five cases of ANPCE in China. PATIENTS AND METHODS: The medical data of four women and one man ranging in age from 28 to 46 years (median, 38 years) with ANPCE were reviewed retrospectively at the Zhongshan Ophthalmic Center of Sun Yat-sen University, China. All patients had received local tumor resection and the diagnosis was confirmed by histopathological examination. RESULTS: All five cases experienced blurred vision. The right eye was affected in four cases and the left in one. Slit-lamp biomicroscopy revealed a nodular, non-pigmented, gray-white mass with a slightly irregular surface. Tumor invasion through the peripheral iris was observed in two patients, two patients had multiple iris or ciliary cysts, and one patient had a partially bloodstained cornea. All tumors transmitted light readily. Ultrasound biomicroscopy showed a middle- or hyper-echoic solid mass in the ciliary body. MRI examination showed the tumor hyperintense to vitreous on T1WI and hypointense to vitreous on T2WI. Local resection was performed in all cases. After a median of 5.0 years of follow-up, no tumor recurrence was present in any of the cases and all involved eyes were saved. The visual acuity improved seven lines in three cases, decreased one line in one case, and vision was lost in one case. CONCLUSIONS: ANPCE often presents in adults as gray-white in color, with an irregular and sometimes multilobulated surface. The tumor transmits light well. Local resection of the mass generally provides the patient with useful vision. Recurrence after surgical removal is unlikely.

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.

Molecular cloning and protein characterization of swine 4-1BB.

4-1BB is expressed on activated T cells and other immune and non-immune cells. It plays important roles in human and mouse T cell function. However, the swine 4-1BB sequence remains unknown and its role in swine T cell response has not been studied. In the present study, we for the first time described the cloning of the swine 4-1BB gene and the property of the protein. Two 4-1BB variants were detected in swine. The coding sequences of variant 1 and variant 2 were 768 and 726 nucleotides in length, respectively, and both variants were coded by 7 exons in the swine genome. Comparison of nucleotide and amino acid sequences showed that both swine 4-1BB variants were more closely related to bovine and human sequences than to either the mouse or rat sequence. Prediction analysis showed that swine 4-1BB belonged to the tumor necrosis factor receptor (TNFR) superfamily like human and mouse 4-1BB and the tertiary structures of the swine 4-1BB variants were much more similar to mouse 4-1BB than to human 4-1BB. The 1556bp 5' regulatory sequence cloned by nested PCR efficiently induced green fluorescent protein expression in porcine peripheral blood mononuclear cells (PBMC) post nucleofection. Moreover, 4-1BB protein was widely expressed in pig tissues and both variants of swine 4-1BB protein were transmembrane proteins and expressed on the membrane of porcine PBMCs.

[Researches on the effect of gas humidity on photoacoustic spectroscopy gas detection system].

Environmental influence is the important factor in a photoacoustic spectroscopy gas detection (PASGD) system when it is applied in the industrial field. The experiments show that the sensitivity of condenser microphone is affected mostly by the humidity of the gas under test, leading to the PASGD's result drift. The present paper puts forward a method to eliminate the influence of gas humidity. A speaker is fixed in the photoacoustic cell, whose amplitude is regarded as the sensitivity self-adaption characterization of sound sensor, used to correct the photoacoustic signal amplitude. Thus the problem of sensitivity changing in sound detection with condenser microphone is solved. Based on this method, a photoacoustic experimental setup, equipped with a diode laser, a resonant photoacoustic cell and a lock-in amplifier, was applied to compare the test for different humidity samples. The results show that this method is useful to eliminating the gas humidity influence and enhancing environmental adaptability of PASGD system.

Evaluation of Toxoplasma gondii as a live vaccine vector in susceptible and resistant hosts.

BACKGROUND: Toxoplasma gondii has been shown to trigger strong cellular immune responses to heterologous antigens expressed by the parasite in the inbred mouse model. We studied the immune response induced by T. gondii as an effective vaccine vector in chickens and rabbits. RESULTS: T. gondii RH strain was engineered to express the yellow fluorescent protein (YFP) in the cytoplasm. A subcutaneous injection of the transgenic T. gondii YFP in chickens afforded partial protection against the infection of transgenic E. tenella YFP. T. gondii YFP induced low levels of antibodies to YFP in chickens, suggesting that YFP specific cellular immune response was probably responsible for the protective immunity against E. tenella YFP infection. The measurement of T-cell response and IFN-γ production further confirmed that YFP specific Th1 mediated immune response was induced by T. gondii YFP in immunized chickens. The transgenic T. gondii stimulated significantly higher YFP specific IgG titers in rabbits than in chickens, suggesting greater immunogenicity in a T. gondii susceptible species than in a resistant species. Priming with T. gondii YFP and boosting with the recombinant YFP can induce a strong anti-YFP antibody response in both animal species. CONCLUSIONS: Our findings suggest that T. gondii can be used as an effective vaccine vector and future research should focus on exploring avirulent no cyst-forming strains of T. gondii as a live vaccine vector in animals.

The molecular mechanism of endoplasmic reticulum stress-induced apoptosis in PC-12 neuronal cells: the protective effect of insulin-like growth factor I.

Endoplasmic reticulum (ER) stress has been implicated in several neurodegenerative diseases. Although CCAAT/enhancer-binding protein homologous protein (CHOP) has been shown to play a critical role in ER stress, the precise apoptosis cascade downstream of CHOP is unknown. In this report, we investigated the mechanism of ER stress-mediated apoptosis as well as the action of IGF-I in PC-12 neuronal cells. Our results demonstrated that tribbles-related protein 3 (TRB3), which is a target gene of CHOP, was responsible for tunicamycin (an ER stress inducer)-induced apoptosis. TRB3 could promote dephosphorylation of Akt in PC-12 cells. IGF-I inhibited ER stress-induced apoptosis by restoring the phosphorylation level of Akt. Both wortmannin (a phosphatidylinositide 3-kinase inhibitor) and SB 212090 (a p38 MAPK inhibitor) suppressed the protective effect of IGF-I on ER stress-induced apoptosis. Interestingly, IGF-I attenuated ER stress-mediated expression of TRB3 but not CHOP. This action of IGF-I was abolished by SB 212090 but not by wortmannin. Immunoprecipitation analysis revealed that IGF-I promoted the phosphorylation of CHOP by activating p38 MAPK, probably leading to a decrease in the transcriptional activity of CHOP. The dephosphorylation of Akt resulted in increased expression of a proapoptotic protein, p53 up-regulated modulator of apoptosis (PUMA), in a forkhead box O3a-dependent manner. Knockdown of PUMA by short hairpin RNA attenuated ER stress-mediated apoptosis. Thus, our current study indicates that both TRB3 and PUMA are critical molecules in ER stress-induced apoptosis. IGF-I effectively protects PC-12 neuronal cells against ER stress-induced apoptosis through the phosphatidylinositide 3-kinase/Akt and p38 MAPK pathways.

[Effect of reducing caloric intake on mice transplanted with S180 ascitic cancer].

OBJECTIVE: To examine the effect of different reduced caloric intake on mice transplanted with S180 ascitic tumor. METHODS: The institute for cancer research (ICR) mice were randomly divided into control group, 3.0 standard feed (SF) group, 2.0 SF group and 1.3 SF group. The mice in control group were fed enough (about 5 g/d) dietary intake, while the amounts of dietary intake in the latter three groups were scaled down in the proportion of 65%, which were 3.0 g, 2.0 g and 1.3 g standard feed respectively. Meanwhile the essential vitamins were added to the latter three groups to keep the amount of intake the same as that of the control's. RESULTS: For most of the mice, the caloric intake obviously prolonged the mean survival days and improved the life quality was 7.14 kcal/d, and the fasting blood glucose level was 2-3 mmol/L. CONCLUSION: Properly reduced caloric intake and keeping lower blood glucose level is beneficial to prolonging the survival time of mice transplanted with S180 ascitic cancer.