A novel peptide identified from skin secretions of Bombina maxima possesses LPS-neutralizing activity.

Lipopolysaccharide (LPS) is a major pathogenic factor in endotoxin shock or sepsis. Most antibiotics have little clinical anti-endotoxin activity, but some antimicrobial peptides (AMPs) have been shown to be effective in blocking LPS. We identified a novel peptide from the skin secretions of Bombina maxima (B. _maxima) by challenging the skin of frogs with an LPS solution. Peptide 2 has an amino acid sequence of LVGKLLKGAVGDVCGLLPIC. Peptide 2 possesses low hemolytic activity, low cytotoxicity against RAW 264.7 cells, and strong anti-inflammatory activity. Moreover, peptide 2 plays an anti-inflammatory role by inhibiting inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). A biolayer interferometry (BLI) assay indicated that peptide 2 binds to LPS with strong affinity and that this interaction has an affinity constant (KD) value of 1.05 × 10-9 M. A survival study showed that peptide 2 possesses potent LPS-neutralizing activity to protect LPS-treated mice from death. In conclusion, we have identified a potent peptide with LPS neutralizing activity, which lays a foundation for future research and development.

Molecular characterization and functional analysis of four teleostean K+ channels in macrophages of sea perch (Lateolabrax japonicas).

Potassium ion channels are one of the most diversely and widely distributed channels, which are involved in all kinds of physiological functions in both excitable and non-excitable cells. The expression of voltage-gated potassium ion (Kv) channels is highly variable according to the state of macrophages activation. Macrophages have an important function in innate immunity against intruding pathogens. They produce a variety of inflammatory and immunoactive molecules that modulate imflammatory responses. Here we show that blockade of K+ channels by non-selective Kv channel inhibitor tetraethylammonium chloride (TEA), and 4-aminopyridine (4-AP) inhibited proinflammatory cytokines expression, cell proliferation, and reactive oxygen species (ROS) production in LPS-stimulated macrophages of Sea perch (Lateolabrax japonicas). Then we isolated four Kv channels genes (spKv1.1, spKv1.2, spKv1.5 and spKv3.1) in LPS-activated fish macrophages. These channels genes were up-regulated after LPS stimulation except spKv3.1, which remained unchanged during the test. The results of this study indicate that Kv channels could be required for modulating the immune function of fish macrophages.

Molecular cloning and functional analysis of a voltage-gated potassium channel in lymphocytes from sea perch, Lateolabrax japonicus.

Voltage-gated potassium (Kv) channels on cell plasma membrane play an important role in both excitable cells and non-excitable cells and Kv1 subfamily is most extensively studied channel in mammalian cells. Recently, this potassium channel was reported to control processes inside mammalian T lymphocytes such as cell proliferation and volume regulation. Little is known about Kv1 channels in fish. We have postulated the presence of such a channel in lymphocytes and speculated its potential role in immunoregulation in fish. Employing specific primers and RNA template, we cloned a segment of a novel gene from sea perch blood sample and subsequently obtained a full cDNA sequence using RACE approach. Bioinformatic analysis revealed structural and phylogenetic characteristics of a novel Kv channel gene, designated as spKv1.3, which exhibits homologous domains to the members of Kv1.3 family, but it differs notably from some other members of that family at the carboxyl terminus. Full-length of spKv1.3 cDNA is 2152 bp with a 1440 bp open reading frame encoding a protein of 480 amino acids. SpKv1.3 gene is expressed in all of the tested organs and tissues of sea perch. To assess the postulated immune function of spKv1.3, we stimulated lymphocytes with LPS and/or channel blocker 4-AP. Expression levels of messenger RNA (mRNA) of spKv1.3 under stimulation conditions were measured by quantitative RT-PCR. The results showed that LPS can motivate the up-regulation of spKv1.3 expression significantly. Interestingly, we found for the first time that 4-AP with LPS can also increase the spKv1.3 mRNA expression levels in time course. Although 4-AP could block potassium channels physically, we speculated that its effect on blockage of potassium channel may start up an alternative mechanism which feed back and evoke the spKv1.3 mRNA expression.

Biodegradation of crude oil by an Arctic psychrotrophic bacterium Pseudoalteromomas sp. P29.

A psychrotrophic petroleum-degrading bacterium Pseudoalteromonas sp. P29 was isolated from marine sediment, which was collected during 2nd Chinese Arctic Scientific Expedition. The phenotypic character and biodegradation efficiency on mixed oil or vacuum oil were tested at low temperature. The strain Pseudoalteromonas sp. P29 grew in a range of temperature from 5 to 35 degrees C and the optimum temperature was 25 degrees C. Gas chromatography analysis indicated that the strain might preferentially metabolize shorter-chain alkanes. The biodegradation efficiency were nearly 90 and 80%, respectively, after incubation at 5 degrees C for 28 days in the mineral medium supplement with mixed oil or vacuum oil as the sole carbon and energy source. The results showed a possible exploitation of the strain in future biotechnological processes especially in cold contaminated environments.

[Facilitation of Shengjingbao to spermatogenesis in oligospermia mouse models and its action mechanisms].

OBJECTIVE: To investigate the effects of Shengjingbao on spermatogenesis in the mouse model of oligospermia and its action mechanisms. METHODS: Sixty male mice were randomly divided into 4 groups, Shengjingbao (Group 1), Vitamin E (Group 2), blank model control (Group 3) and normal blank control (Group 4). The first three groups were treated by celiac injection of cyclophosphamide for 5 successive days to make models, followed by intragastric administration of Shengjingbao and Vitamin E to Group I and 2, respectively, for 36 days. And then all the mice were sacrificed. The serum testosterone (T) level was determined by radioimmunology, and a suspension was made from the testis and epididymis of one side for sperm analysis, while the testis of the other side was sliced up and stained by HE method and TUNEL technique to detect the count of Leydig cells, the layers of spermatogenic epithelia and the apoptosis of spermatogenic cells. RESULTS: Compared with Group 3, the serum T level, the layers of spermatogenic epithelia and the count of Leydig cells were obviously improved and even exceeded those in Group 2. The positive expression rate of spermatogenic cell apoptosis in Group 1 was evidently lower than Group 2 and 3. The above differences were statistically significant (P < 0.01 or P < 0.05), but no significant difference was noted between Group 1 and 4. CONCLUSION: Shengjingbao can significantly increase the count of Leydig cells, elevate the T level that influences the layers of spermatogenic epithelia, and thus enhance spermatogenesis. The action mechanisms of Shengjingbao may lie in its capacity of inhibiting the apoptosis of spermatogenic cells, increasing the layers of spermatogenic epithelia and facilitating spermatogenesis. T may play a role in inhibiting the apoptosis of spermatogenic cells.

[Cultivation of fibroblasts derived from urethral scar and the effects of salviae miltiorrhizae and ligustrazine on its growth].

OBJECTIVE: To explore the possible effect and related mechanism of salviae miltiorrhizae (SM) and ligustrazine in the treatment of urethral scar. METHODS: In vitro cultivation of fibroblasts derived from urethral scar has been developed. The effects of these two medicines on its morphology and proliferation have been detected based on the in vitro culture system. RESULTS: The spindle cells were found to become elliptical in shape. The two medicines inhibited the proliferation of fibroblasts derived from urethral scar, and this may be resulted from their inhibitive effects on cell division rather than cell necrosis or degradation. CONCLUSION: Salviae multiorrhizae and ligustrazine as effective scar inhibitors may have application prospects in the treatment of urethral stricture.