Insights into the in vitro digestibility of pork myofibrillar protein with different ionic polysaccharides from the perspective of gel characteristics.

In this work, the simulated gastrointestinal digestion of myofibrillar protein gels (MPGs) with anionic xanthan (XMP) and sodium alginate (SMP)/cationic chitosan (CSMP)/neutral curdlan (CMP) and konjac (KMP) was investigated to develop muscle-gelled foods with good qualities before and after eating. The results indicated that the neutral CMP and KMP groups had higher gel strength and protein digestibility than the CSMP group. Xanthan and sodium alginate facilitated myosin degradation in gastrointestinal digestion because of the weak wraps between protein and anionic polysaccharides, gaining plentiful peptides (1790 and 1692 respectively) with molecular weights below 2000 Da. Chitosan and neutral curdlan could improve the strength of MP gel but inhibited proteolysis and resulted in low contents of released amino acids via the strong cross-linked network blocking trypsin contact. This work provides a theoretical basis for developing low-fat meat products with good qualities and digestion behaviors by simply controlling the ionic types of polysaccharides.

[Decreasing toxicity and synergistic effects of intracellular and extracellular polysaccharides from Phellinus igniarius to tumor-bearing mice].

To study the toxicity-decreasing and synergistic effect of intracellular and extracellular polysaccharides from Phellinus igniarius on S180 mice. The PIP and PIE were extracted from the products of liquid submerged fermentation of P. igniarius. Transplanting S180 mice tumor models were established so as to observe the changes in tumor inhibiting rate, indexes of the spleen and thymus, body weight, peripheral blood cells and IFN-gamma levels when CTX was used alone and when used in combination with the PIP and PIE from P. igniarius. The results indicate that the PIP and PIE from P. igniarius can increase the activity of body immunity, attenuate the toxicity of CTX as well, and improve the anti-tumor effects.

Effects of Different Ionic Polysaccharides in Cooked Lean Pork Batters on Intestinal Health in Mice.

The effects of cooked lean pork batters with three ionic types of polysaccharides (anionic xanthan-gum/sodium-alginate, neutral curdlan-gum/konjac-gum and cationic chitosan) on the intestinal health of mice were investigated in this study. The results showed that the zeta potential in the sodium-alginate group (−31.35 mV) was higher (p < 0.05) than that in the chitosan group (−26.00 mV), thus promoting the protein hydrolysis in the anionic group because of electrostatic repulsion. The content of total free amino acids in the small intestine in the xanthan-gum and sodium-alginate groups (2754.68 µg and 2733.72 µg, respectively) were higher (p < 0.05) than that in the chitosan group (1949.78 µg), which could decrease the amount of undigested protein entering the colon. The two anionic groups could also increase the abundance of Lactobacillus and the balance of Faecalibaculum and Alistipes in the colon. The content of proinflammatory factor IL−6 of colon tissues in the sodium-alginate group (1.02 ng/mL) was lower (p < 0.05) than that in chitosan, curdlan-gum and konjac-gum groups (1.29, 1.31 and 1.31 ng/mL, respectively). The result of haematoxylin-eosin staining of the colon also revealed that sodium alginate was beneficial for colonic health. The two neutral groups increased the content of faecal short-chain fatty acids in mice. These results demonstrated that anionic polysaccharides have potential for developing functional low-fat meat products.

Anti-tumour effects of polysaccharide extracted from Acanthopanax senticosus and cell-mediated immunity.

Acanthopanax senticosus, also known as Siberian ginseng, is widely distributed throughout northern Asia and used in traditional Chinese medicine; it has been reported to prevent a number of diseases. However, the association between the antitumour and immunostimulatory activities of polysaccharide extracted from A. senticosus (ASPS) remains to be elucidated. The aim of the present study was to investigate the anti-tumour and immunomodulatory effects of polysaccharide extracted from ASPS on Crocker sarcoma S180, hepatic carcinoma H22 and uterine cervical carcinoma U14 tumour cell lines implanted in mice. High performance liquid chromatography, gas chromatography and infrared spectroscopy were used to analyse the monosaccharide composition of ASPS. The monosaccharide composition of ASPS (Arabic candy: Xylose: Glucose: Mannose) was 7.1:22.3:7.6:1.0. On day 0, female Kunming mice, were injected subcutaneously with 1×108 tumour cells in 0.2 ml. The inoculated mice were subsequently divided into five groups (10 mice/group) as follows: Model group, treated with normal saline; positive control group, treated with 30 mg/kg cyclophosphamide (CTX); and three treatment groups, treated with 200, 100 or 50 mg/kg ASPS. Non-inoculated mice were divided into the normal group, which was treated with normal saline, and the negative control group, which was treated with 200 mg/kg ASPS (n=10/group). CTX and ASPS were administered intragastrically once daily for 10 days. All mice were sacrificed on day 11. ASPS was observed to have an inhibitory effect on the growth of S180, H22 and U14 cells in solid and ascites tumour-bearing mice. Serum interleukin (IL)-2 and IL-12 levels were significantly increased in S180 solid tumour-bearing mice treated with 200 or 100 mg/kg ASPS compared with mice in the normal, control and model groups (P<0.05), whereas serum IL-2 and IL-12 levels were significantly decreased in the cyclophosphamide treatment group compared with the normal, control and model groups (P<0.05). No significant difference in serum levels of tumour necrosis factor-α level was observed between any groups. In S180 and U14 solid tumour-bearing mice, no significant differences in serum levels of interferon (INF)-γ level in were observed between groups; however, in H22 solid tumour-bearing mice, treatment with ASPS significantly increased serum INF-γ compared with the positive control group (P<0.05). The results may provide a basis for the potential application of ASPS in clinical treatment for cancer.

Detection of very early antibody to native HIV antigens by HIV neutralization and live-cell immunofluorescence assays.

Very early detection of HIV infection could help decrease the spread of HIV, improve safety of the blood supply, and permit earlier treatment. Early detection was reported when native gp41 antigen was used to detect antibodies that occurred 2-6 weeks earlier than detection of antibodies to denatured antigens by the current EIA or WB tests or detection by the HIV RNA test. We hypothesized that early antibodies to native gp41/160 could be detected, not only by the reported live-cell immunofluorescence (IFA) but also by a neutralization test, since virions as well as HIV-infected cells contain native gp41/160. To test this hypothesis, we did an initial test of concept study to compare the neutralization test with other tests, using sera from 12 high-risk patients. The neutralization test reproducibly detected early antibodies (characterized) in the sera of 10 of 12 (83%) high-risk subjects. Importantly, the EIA and WB tests that use denatured antigens missed the early diagnosis in 12 of the 13 subjects (92%). The findings support the concept that native HIV antigens can detect polyclonal HIV neutralizing antibodies and live-cell IFA antibodies earlier than currently available tests that use denatured antigens.

Endo-polysaccharide of Phellinus igniarius exhibited anti-tumor effect through enhancement of cell mediated immunity.

The purpose of this study was to assess the anti-tumor and immunomodulatory effects of PIE on tumor cells Sarcoma 180 and Hepatoma 22 in implanted mice. The monosaccharide composition of PIE was analyzed by GC. The results demonstrated that PIE monosaccharide composition was n(Xyl): n(Man): n(Fuc): n(Glc): n(Gal)=2.3: 1: 6.4: 22.1: 19.83. The oral administration of PIE characteristically inhibited the growth of S180 and H22 cells and increased the life span. The concentrations of serum IL-2 and IL-18 were significantly increased in the S180 implanted mice fed with PIE in the doses of 500 mg/kg and 250 mg/kg compared with those in control (p<0.01). The concentrations of serum IL-2 were significantly increased in H22 implanted mice in the doses of 500 mg/kg and 250 mg/kg compared with those in control (p<0.01).

Is human immunodeficiency virus RNA load composed of neutralized immune complexes?

During acute human immunodeficiency virus (HIV) infection, both virus load (HIV RNA) and infectivity are high (10(3)-10(7) RNA copies/mL or TCID(50)/mL) until antibody is produced, which may reduce the HIV infectivity. In HIV carriers, the HIV RNA load is elevated (10(3)-10(5) copies/mL), but infectivity is low (10(0)-10(2) TCID(50)/mL). The low infectivity in carriers could be due to neutralization by antibody in serum, resulting in immune complexes (ICs). We demonstrated that ICs in plasma, prepared with protein A beads, contained HIV RNA (80%-100%) in association with immunoglobulin G (IgG). In comparison, ICs from patients with acute HIV infection and little or no antibody contained virtually no HIV RNA. Moreover, ICs prepared by ultrafiltration contained IgG and specifically and irreversibly neutralized HIV, which indicates that the ICs contained neutralizing antibody. These findings indicate that the HIV RNA in the plasma of carriers is frequently composed of antibody-neutralized HIV as ICs.