[Vincristine inhibits the proliferation of ovarian cancer cells by regulating the demethylation of RASSF2A]

Objective: To investigate the effect of vincristine on the proliferation of ovarian cancer cells by regulating RASSF2A demethylation. Methods: SKOV3 cells were infected with control (LV-NC) and RASSF2A lentivirus (LV-RASSF2A) and treated with or without vincristine. Cell counting kit-8 (CCK-8) was used to detect the activity of ovarian cancer cells (SKOV3) treated with different doses of vincristine. Colony formation assay was used to detect the proliferation of SKOV3 cells. Flow cytometry was used to detect the apoptosis of SKOV3 cells. Real time polymerase chain reaction (RT-PCR) was used to examine the mRNA expression of RASSF2A in IOSE-29 and SKOV3 cells. Western blot was used to examine the protein expression of RASSF2A in IOSE-29 and SKOV3 cells. Methylation-specific PCR was used to detect methylation and demethylation levels of RASSF2A gene in IOSE-29 and SKOV3 cells. Results: The cell viabilities of SKOV3 cell treated with 6.25 nmol/L, 12.5 nmol/L, 25 nmol/L, 50 nmol/L and 100 nmol/L vincristine were (87.19±4.49)%, (73.67±8.62)%, (66.35±6.04)%, (50.32±6.00)% and (34.92±6.11)%, respectively, lower than (100.46±4.69)% of control group (P<0.05). The half maximal inhibitory concentration of vincristine at 48 hours was 50.02 nmol/L. The proliferation abilities of SKOV3 cells in vincristine 12.5 nmol/L group, 25 nmol/L group and 50 nmol/L group were (41.70±2.21)%, (32.15±1.80)% and (23.00±2.01)%, respectively, significantly lower than (100.78±5.66)% in the control group (all P<0.05). The apoptotic rates of SKOV3 cells in vincristine 12.5 nmol/L group, 25 nmol/L group and 50 nmol/L group were (3.65±0.27)%, (5.21±0.76)% and (10.46±1.00)%, respectively, significantly higher than (2.12±0.23)% in the control group (all P<0.05). Compared with the IOSE-29 group (1.00±0.07 and 0.68±0.04), the mRNA expression (0.32±0.04) and protein expression (0.24±0.02) of RASSF2A were down-regulated in SKOV3 cells (P<0.05). Compared with the LV-NC group [(101.60±4.39)%, (100.73±3.29)%, (4.06±0.30)%], over-expression of RASSF2A down-requlated cell viability (68.92±3.94)%, inhibited proliferation (16.38±2.16)%, and promoted apoptosis (8.65±0.56)%, (P<0.05). Conclusion: Vincristine can increase RASSF2A expression and inhibit ovarian cancer cell proliferation by promoting the demethylation of RASSF2A promoter.

[Analysis of discordance between HbA1c and FPG criteria for dysglycemia screening in physical examination individuals]

The general data, blood routine, liver and kidney function, glucose metabolism and lipid metabolism of 11 922 participants who underwent physical examination at the Health Management Center of the Second Xiangya Hospital of Central South University from January 2019 to December 2019 were collected. Clinical characteristics and independent factors of patients with discordance between HbA1c and FPG were evaluated and analyzed. The prevalence of HbA1c-defined diabetes and prediabetes (respectively 8.13%, 34.79%) were significantly higher than that in FPG-defined diabetes and prediabetes (respectively 4.70%, 8.97%) (χ²=2 635.940;P<0.001). The prevalence of inconsistence between HbA1c and FPG was 35.65% and increased with increasing age. This inconsistence mainly occurred in population with HbA1c:5.7%-6.0% and FPG<5.6 mmol/L, followed by population with HbA1c:6.1%-6.4% and FPG<5.6 mmol/L. The risk factors of inconsistency included advanced age, overweight or obesity, hypoalbuminemia, dyslipidemia and hyperuricemia. Among these special participants, compared with participants under 45 years old, participants with over 45 years of age (OR=3.525, 95%CI: 3.216-3.863, P<0.001) were more likely to have inconsistence between HbA1c and FPG; and overweight participants (OR=1.474, 95%CI: 1.341-1.620, P<0.001) or obese participants (OR=1.856, 95%CI: 1.633-2.110, P<0.001) are prone to have the inconsistence than those with normal weight.

Saturation cavity ring-down spectrometry using a dynamical relaxation model

We propose a new simple approximate solution to the two-state rate equation model for analyzing decay signals of saturation cavity ring-down spectrometry in the adiabatic and low-saturation regime. It helps obtain baseline-immune Doppler-free spectra for hyperfine transitions and linear absorption coefficients of a gas in the saturation regime. To demonstrate it, a baseline-immune Lamb dip spectrum of the R1A2 transitions in the 2v₂ + v₃ band of methane was recorded. The line position was determined to be 6 076.108 457 7(11) cm^-1, the relative uncertainty being 1.8 × 10^-10.

Discovery of New Lines in the R9 Multiplet of the 2v_{3} Band of ^{12}CH_{4}

We present the first results for resolving methane (CH_{4}) line transition frequencies down to the kilohertz level for overlapping lines using comb-linked cavity ring-down spectroscopy, while most available laboratory measurements, having resolution at the megahertz level, cannot separate merged lines. To demonstrate the technique, Lamb-dip spectra and linear-absorption spectra were used to identify overlapped lines of vibration-rotation spectra in the R9 multiplet of the 2v_{3} band. Three new weak lines were found for the first time. The experimental methods are extensible to other important bands of CH_{4} and many other gas-phase molecules, and should provide a more detailed understanding of molecular structure and line parameters for future high-precision studies.

[Minocycline inhibits formalin-induced inflammatory pain and the underlying mechanism]

OBJECTIVE

To unravel the underlying mechanism of minocycline in formalin-induced inflammatory pain, and to investigate the effects of minocycline on synaptic transmission in substantia gela-tinosa (SG) neurons of rat spinal dorsal horn.

METHODS

Behavioral and immunohistochemistry experiments: 30 male Sprague-Dawley (SD) rats (3-5 weeks old) were randomly assigned to control (n=8 rats), model (n=8 rats), saline treatment model (n=6 rats) and minocycline treatment model (n=8 rats) groups. The control group was subcutaneously injected with normal saline on the right hindpaws. Acute inflammatory pain model was established by injecting 5% (volume fraction) formalin into the right hindpaws. The rats in the latter two groups received intraperitoneal injection of saline and minocycline 1 h before the formalin injection, respectively. The time of licking and lifting was recorded every 5 min within 1 h after the subcutaneous injection of normal saline or formalin for all the groups, which was continuously recorded for 1 h. One hour after the pain behavioral recording, the spinal cord tissue was removed following transcardial perfusion of 4% paraformaldehyde. The expression of c-Fos protein in spinal dorsal horn was observed by immunohistochemistry. Electrophysiological experiment: In vitro whole-cell patch-clamp recordings were performed in spinal cord parasagittal slices obtained from 26 male SD rats (3-5 weeks old). Two to five neurons were randomly selected from each rat for patch-clamp recording. the effects of minocycline, fluorocitrate and doxycycline on spontaneous excitatory postsynaptic currents (sEPSCs) or spontaneous inhibitory postsynaptic currents (sIPSCs) of SG neurons were investigated.

RESULTS

Compared with the control group, both the licking and lifting time and the expression of c-Fos protein in ipsilateral spinal dorsal horn of the model group were significantly increased. Intraperitoneal injection of minocycline largely attenuated the second phase of formalin-induced pain responses (t=2.957, P<0.05). Moreover, c-Fos protein expression was also dramatically reduced in both the superficial lamina (I-II) and deep lamina (III-IV) of spinal dorsal horn (t_I-II=3.912, t_III-IV=2.630, P<0.05). On the other side, bath application of minocycline significantly increased the sIPSCs frequency to 220%±10% (P<0.05) of the control but did not affect the frequency (100%±1%, t=0.112, P=0.951) and amplitude (98%±1%, t=0.273, P=0.167) of sEPSCs and the amplitude (105%±3%, t=0.568, P=0.058) of sIPSCs. However, fluorocitrate and doxycycline had no effect on the frequency [(99%±1%, t=0.366, P=0.099); (102%±1%, t=0.184, P=0.146), respectively] and amplitude [(98%±1%, t=0.208, P=0.253); (99%±1%, t=0.129, P=0.552), respectively] of sIPSCs.

CONCLUSION

Minocycline can inhibit formalin-induced inflammatory pain and the expression of c-Fos protein in spinal dorsal horn. These effects are probably due to its enhancement in inhibitory synaptic transmission of SG neurons but not its effect on microglial activation or antibiotic action.

Temperature-scanning saturation cavity ring-down spectrometry for Doppler-free spectroscopy

Saturation cavity ring-down spectroscopy (SCRDS) is a powerful Doppler-free spectroscopy means for measuring absolute frequencies of transitions at the ultra-low uncertainties. We report in this paper a simple way to implement it by temperature scanning the cavity length, which circumvents the need for a complex optical cavity-length stabilization system based upon a piezoelectric actuator (PZT). To demonstrate this approach, the absolute frequencies of the two transitions, R6F1 of the 2v₃ and Q9A1 of the 2v₂ + v₃ bands, of ¹²CH₄, are determined to be 182 185 269.362(20) MHz and 182 187 617.543(39) MHz. The accuracy of measurements is improved by about 3-4 orders of magnitude when compared to those obtained with conventional spectroscopic methods.

The Boltzmann project

The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of the Consultative Committee for Units (CCU) on the redefinition of the kilogram, ampere, kelvin and mole. For the redefinition of the kelvin, the Boltzmann constant will be fixed with the numerical value 1.380 649 × 10-23 J K-1. The relative standard uncertainty to be transferred to the thermodynamic temperature value of the triple point of water will be 3.7 × 10-7, corresponding to an uncertainty in temperature of 0.10 mK, sufficiently low for all practical purposes. With the redefinition of the kelvin, the broad research activities of the temperature community on the determination of the Boltzmann constant have been very successfully completed. In the following, a review of the determinations of the Boltzmann constant k, important for the new definition of the kelvin and performed in the last decade, is given.

Determination of the Boltzmann constant with cylindrical acoustic gas thermometry: new and previous results combined

We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previous work (Zhang et al 2011 Int. J. Thermophys.32 1297, Lin et al 2013 Metrologia50 417, Feng et al 2015 Metrologia52 S343) that determined the length of a different cavity using two-color optical interferometry. In this new study, the half-widths of the acoustic resonances are closer to their theoretical values than in our previous work. Despite significant changes in resonator design and the way in which the cylinder length is determined, the value of kB is substantially unchanged. We combined this result with our four previous results to calculate a global weighted mean of our kB determinations. The calculation follows CODATA's method (Mohr and Taylor 2000 Rev. Mod. Phys. 72 351) for obtaining the weighted mean value of kB that accounts for the correlations among the measured quantities in this work and in our four previous determinations of kB. The weighted mean k̂B is 1.380 6484(28) × 10-23 J K-1 with the relative standard uncertainty of 2.0 × 10-6. The corresponding value of the universal gas constant is 8.314 459(17) J K-1 mol-1 with the relative standard uncertainty of 2.0 × 10-6.

[Spinal analgesic mechanism of minocycline in formalin-induced inflammatory pain]

Objective: To investigate the spinal analgesic mechanism of minocycline in formalin-induced inflammatory pain. Methods: Behavioral test: Male Sprague-Dawley rats(3-5-week old) were randomly assigned into four groups: control, model, vehicle-controlled and minocycline group. Ten percent neutral formalin was injected subcutaneously into the right hind paw dorsum of the rats in model, vehicle-controlled and minocycline group. Normal saline was injected subcutaneously into the right hind paw dorsum of the rats in control group. Before 1 h of formalin injection, the rats in vehicle-controlled and minocycline group received intraperitoneal injection of saline and minocycline, respectively. Licking and lifting time was observed as the behavior results of inflammatory pain. Electrophysiologic experiment: In vitro spinal cord parasagittal slices were prepared from the same rats as above. The effect of minocycline on spontaneous inhibitory postsynaptic currents(sIPSCs) of substantia gelatinosa(SG) neurons was observed using whole-cell patch-clamp technique. Results: Compared with the control group, the licking and lifting time in the model group was significantly increased. Compared with the vehicle-controlled group, the licking and lifting time in the minocycline group was significantly decreased. Minocycline significantly increased the frequency(t=9.32, P<0.05)but not the amplitude(t=1.54, P>0.05) of sIPSCs of SG neurons, the frequency of sIPSCs of control and minocycline group were (2.5±0.3)Hz and (5.2±0.6)Hz, respectively. When calcium was removed from the extracellular solution, the frequency before and after minocycline perfusion were (0.9±0.1)Hz and (0.9±0.1)Hz, respectively, the amplitude before and after minocycline perfusion were (18.2±0.7)pA and (18.5± 0.6)pA, respectively, the difference of frequency or amplitude was not statistically significant(t=0.32, 0.82, all P>0.05). However, minocycline still increased the frequency of sIPSCs when glutamate receptor antagonists 6-Cyano-7-nitroquinoxaline-2, 3-dione(CNQX) and D-(-)-2-Amino-5-phosphonopentanoic acid(APV) were included in extracellular solution(t=13.51, P<0.05), the frequency of sIPSCs were (2.0±0.1)Hz and (4.3±0.4)Hz, respectively. Minocycline still increased the frequency of IPSCs when voltage-gated sodium channel blocker tetrodotoxin(TTX) were included in extracellular solution(t=8.67, P<0.05), the frequency of IPSCs were (2.2±0.2)Hz and (5.2±0.5)Hz. Conclusion: Minocycline can attenuate formalin-induced inflammatory pain which may be associated with its increase in the inhibitory synaptic transmission of SG neurons.

[The effect of transforming growth factor β(1) in the transition of bone marrow-derived macrophages into myofibroblasts during renal fibrosis]

To study which subgroup of bone marrow derived cells formed myofibroblasts and the mechanism that transforming growth factor β(1)(TGFβ(1)) regulates the formation of bone marrow derived macrophages into myofibroblasts during renal fibrosis. Chimeric mice were generated by lethally irradiation of C57 mice followed by transfusion of green fluorescent protein (GFP) labeled bone marrow cells. Complete marrow reconstitution was developed until 12 weeks after transplantation. The mice were randomly divided into Sham operation group, unilateral ureteral obstruction (UUO) 3 days group, UUO5 days group, UUO7 days group and UUO7 with TGFβ(1) treatment group. Each group had four mice. Flow cytometry was used to evaluate cell components. Compared with Sham operation group the proportions of GFP(+) CD(14)(+)α-smooth muscle actin(α-SMA)(+) cells, GFP+ CD(44)(+)CD(105)(+)α-SMA(+) cells and GFP(+) F4/80(+) α-SMA(+) cells in each UUO group were progressively increased and the transformation rate in UUO7 day group was the highest. The GFP(+) F4/80(+) α-SMA(+) cells accounted for the largest population. TGFβ(1) promoted the transformation of bone marrow derived macrophages into myofibroblasts. Compared with Sham operation group or UUO7 day group, the proportion of GFP(+) F4/80(+) α-SMA(+) cells increased in UUO7 day TGFβ(1) treatment group. Compared with Sham operation group (or UUO7 days group) the protein expressions of F4/80, α-SMA, Collagen Ⅰ increased in UUO7 with TGFβ(1) group. Bone marrow derived macrophages are considered as the main type of myofibroblast precursors during the development of renal fibrosis. TGFβ(1) regulates the transformation of bone marrow-derived macrophages into myofibroblasts. This process contributes to progressive renal fibrosis and deterioration of renal function.

Determination of the molar mass of argon from high-precision acoustic comparisons

This article describes the accurate determination of the molar mass M of a sample of argon gas used for the determination of the Boltzmann constant. The method of one of the authors (Moldover et al 1988 J. Res. Natl. Bur. Stand.93 85-144) uses the ratio of the square speed of sound in the gas under analysis and in a reference sample of known molar mass. A sample of argon that was isotopically-enriched in ⁴⁰Ar was used as the reference, whose unreactive impurities had been independently measured. The results for three gas samples are in good agreement with determinations by gravimetric mass spectrometry; (〈M_acoustic/M_mass-spec〉 - 1) = (-0.31 ± 0.69) × 10^-6, where the indicated uncertainty is one standard deviation that does not account for the uncertainties from the acoustic and mass-spectroscopy references.

Steroids administered after vacuum-assisted biopsy in the management of idiopathic granulomatous mastitis

AIMS

The aetiology and treatment options for idiopathic granulomatous mastitis (IGM) are controversial. The aim was to study the clinical and diagnostic features and discuss medical and surgical treatment for IGM in our patients.

METHODS

Sixty-five patients who met the histological criteria for IGM were retrospectively studied. The diagnosis of IGM was confirmed using Mammotome (an ultrasound-guided, vacuum-assisted biopsy system), core needle biopsy, quadrantectomy or segmental resection. Forty-five patients were treated with prednisolone (69.2%). Immunohistochemical (IHC) staining for immune-related antigens (CD3, CD4, CD8, CD79a, IgG, and IgM) was performed.

RESULTS

Ultrasonography (USG) was carried out in all patients. Among them, 61 were considered to have an inflammatory mass and 15 had accompanying liquefaction. In four patients, the findings mimicked breast carcinoma (6.2%). The IHC results showed CD3, CD4, CD8 and CD79a lymphocytes diffusely distributed in the lesion. Stains for IgG and IgM were negative. Prednisolone was administered to the patients diagnosed with IGM. The success rate was 53 (81.5%) and the whole recurrence was 12 (18.5%). The median follow-up period was 12 months (range 4-42 months).

CONCLUSIONS

The aetiology of IGM remains uncertain. The disease has no propensity for the right or left breast. It is a local autoimmune disease, involving humoral and cell-mediated immunity. Hyperprolactinaemia may play a role in some patients. Corticosteroids administered after complete removal of the IGM lesion using the Mammotome biopsy system is an effective treatment option.

[Effect of zoledronate on protein interaction between Ca(2+)/calmodulin-dependent protein kinaseⅡ and calmodulin and expression of downstream genes during osteoclast differentiation]

Objective: To investigate the effect of zoledronate on protein interaction between Ca(2+)/calmodulin-dependent protein kinaseⅡ(CaMKⅡ) and calmodulin and protein expression of nuclear factor of activation of T cells-1 (NFATc1) and tartrate resistant acid phosphatase (TRAP) during osteoclast differentiation. Methods: Mouse RAW264.7 cells were divided into group A and B and were cultured. Group A was induced with 50 mg/L receptor activator of NF-κB ligand (RANKL) for osteoclastogenesis, and group B was treated with 1×10(-6) zoledronate for two days from day 2. Co-immunoprcipitation (Co-IP) and reverse Co-IP were used to detect the protein-binding between CaMKⅡ and calmodulin. Western-blotting and immunofluorescent cytochemistry were also used to detect the protein level of NFATc1 and TRAP in both groups. Osteoclast formation was also analyzed. Results: In group B, the number of osteoclasts, number and size of dentin resorption lacunaes were 11.3±1.5, 8.7±2.1 and (5 034.4±775.4) μm(2) respevtively, which were significantly lower than those (37.7±5.7, 23.0±4.0 and [15 042.7±1 906.0] μm(2)) in group A (P<0.01). Co-IP and reverse Co-IP examination indicated that protein-binding between CaMKⅡ and calmodulin significantly decreased by 59.8% and 50.9% in group B compared with group A (P<0.01). The protein level of calmodulin and CaMKⅡ in total cellular proteins also significantly decreased by 52.1% and 51.5% in group B compared with group A (P<0.01). NFATc1 and TRAP protein decreased by 52.4% and 38.9% in group B than in group A (P<0.01), respectively. Conclusions: Zoledronate could significantly inhibit protein-binding between CaMKⅡ and calmodulin and down-regulate protein level of NFATc1 and TRAP.

Recombinant expression and biological characterization of the antimicrobial peptide fowlicidin-2 in Pichia pastoris

Fowlicidins are a group of cathelicidin antimicrobial peptides that were initially identified in chickens. Fowlicidin-2, which is composed of 31 amino acids, is widely expressed in the majority of tissues in chickens and has an important role in innate immunity. In the present study, a recombinant expression system for fowlicidin-2 was successfully constructed using Pichia pastoris X-33 and the expression vector pPICZα-A. Under the optimized fermentation conditions, 85.6 mg fowlicidin-2 with >95% purity was obtained from 1 liter culture medium following purification by ion exchange chromatography and reversed phase high performance liquid chromatography. The recombinant fowlicidin-2 exhibited broad spectrum antimicrobial activity and had a minimum inhibitory concentration ranging from 1 to 4 µM. Furthermore, recombinant fowlicidin-2 exhibited hemolytic activity, promoting 50% human erythrocyte hemolysis in the concentration range of 128-256 µM, and anticancer activity, resulting in the death of 50% of A375 human malignant melanoma cells in the concentration range of 2-4 µM. The results of the present study suggest that recombinant fowlicidin-2 may be a promising candidate for therapeutic applications.

Acoustic and microwave tests in a cylindrical cavity for acoustic gas thermometry at high temperature

Relative primary acoustic gas thermometry (AGT) determines the ratios of thermodynamic temperatures from measured ratios of acoustic and microwave resonance frequencies in a gas-filled metal cavity on isotherms of interest. When measured in a cavity with known dimensions, the frequencies of acoustic resonances in a gas determine the speed of sound, which is a known function of the thermodynamic temperature T. Changes in the dimensions of the cavity are measured using the frequencies of the cavity's microwave resonances. We explored techniques and materials for AGT at high temperatures using a cylindrical cavity with remote acoustic transducers. We used gas-filled ducts as acoustic waveguides to transmit sound between the cavity at high temperatures and the acoustic transducers at room temperature. We measured non-degenerate acoustic modes in a cylindrical cavity in the range 295 K Collapse

Key Words

• acoustic resonator
• cylindrical acoustic gas thermometer
• microwave resonator
• thermodynamic temperature
• waveguide

Collapse

MESH Headings Collapse

Grants

• 9999-NIST Intramural NIST DOC

Collapse

Using a two-capillary viscometer with preheating to measure the viscosity of dilute argon from 298.15 K to 653.15 K

Currently, there exists only one set of experimental results at temperatures up to 680 K with the claimed relative standard uncertainty of (0.15-0.20)%. This paper reports new experimental results using the two-capillary viscometer in the temperature range from 298.15 K to 653.15 K with the claimed relative standard uncertainty of 0.062%. The new measurements agree with the existing high accuracy measurements and ab initio calculations in the overlapping temperature range within the extraordinary low relative differences of ±0.08%. The good agreement represents a robust proof of the potential models derived from the ab initio calculations, which play the powerful means in obtaining the thermophysical properties of dilute monoatomic gases over wide temperature ranges. In the experiments, the authors observed the occurrence of insufficient preheating existing with the two-capillary viscometer at high temperature.

Identification and partial characterization of lactic acid bacteria isolated from traditional dairy products produced by herders in the western Tianshan Mountains of China

Thirty strains of lactic acid bacteria (LAB) were isolated from herders' traditional dairy products collected from Xinjiang, China. The species Lactobacillus, Lactococcus, Enterococcus, Pediococcus and Leuconostoc were identified by 16S ribosomal RNA gene sequencing analysis and conventional observation. The strains' fermentation characteristics, including milk acidification, proteolysis, autolysis, antimicrobial activity and diacetyl production, were assayed and compared. Strains NL24 and NL31 showed the highest proteolytic activity-2·75 and 2·08 mmol Phe l(-1) milk, respectively. Strains C, NL41, SW2, Z3-11, NL42 and Z2-91 had high autolytic activity. In addition, most of the wild strains produced diacetyl, half of them to high levels. This study provides a clue to LAB biodiversity in traditional dairy foods produced by herders in the western Tianshan Mountains. High-performing strains should be further evaluated for practical application in value-added fermented dairy products.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results reveal a certain variety of lactic acid bacteria (LAB) in traditional dairy products from Xinjiang. Some of the LAB strains, such as Lactobacillus rhamnosus NL24 and Lactobacillus paracasei SW2, possess excellent functional properties and have the potential for application in indigenous fermented dairy products. Performance of the newly isolated strains in cheese or yogurt manufacturing was further evaluated. Application of the high-performing strains to enrich the flavour of fermented dairy products is highly desirable and holds great commercial potential.

Cell selectivity and interaction with model membranes of Val/Arg-rich peptides

Antimicrobial peptides are major components of the innate self-defence system and a large number of peptides have been designed to study the mechanism of action. In the present study, a small combinatorial library was designed to study whether the biological activity of Val/Arg-rich peptides is associated with targeted cell membranes. The peptides were produced by segregating hydrophilic residues on the polar side and hydrophobic residues on the opposite side. The peptides displayed strong antimicrobial activity against Gram-negative and Gram-positive bacteria, but weak haemolysis even at a concentration of 256 µM. CD spectra showed that the peptides formed α-helical-rich structure in the presence of negatively charged membranes. The tryptophan fluorescence and quenching experiments indicated that the peptides bound preferentially to negatively charged phospholipids over zwitterionic phospholipids, which corresponds well with the biological activity data. In the in vivo experiment, the peptide G6 decreased the bacterial counts in the mouse peritoneum and increased survival after 7 days. Overall, a high binding affinity with negatively charged phospholipids correlated closely with the cell selectivity of the peptides and some peptides in this study may be likely candidates for the development of antibacterial agents.

Multimerization and fusion expression of bovine lactoferricin derivative LfcinB15-W4,10 in Escherichia coli

Antimicrobial peptides are promising candidates for therapeutic and industrial application owing to their broad spectrum. In this work, a cost-effective method for expression of a potent antimicrobial peptide, bovine lactoferricin derivative LfcinB15-W4,10, has been developed. The oligonucleotide encoding the peptide was linked to generate different oligomeric oligonucleotide segments containing from one to nine but eight tandem copies which was inserted individually to the E. coli expression vector pET32a. The thioredoxin fusion peptides were successfully expressed and detected with different molecular weight on SDS gel, respectively. Among the monomer and other multimeric peptides, the tetramer was expressed at the highest level. After purification, more than 10 mg of tetramer with 99% purity was obtained from 1 l culture and exhibited similar antimicrobial activity as synthetic LfcinB15-W4,10 monomer. The expression system in this study provides a potential production method for lactoferricin derivatives and other antimicrobial peptides in research and industrial applications.

[Systemic breeding of the new variety of Biantiao ginseng (Panax ginseng)]

OBJECTIVE

To breed new varieties of Biantiao ginseng for high yield and fine quality.

METHODS

Systemic breeding methods were applied. About 3,000 outstanding Biantiao ginseng roots were selected and planted in breeding field, and self-crossed for four generations. During the course, inferior lines or plants were rejected. Then strain comparison, identification of resistance to black-speck disease, and analysis of active compositions were carried out.

RESULTS

"Biantiao 1" (BT1), the first new variety of Biantiao ginseng, with green stems and thick, long, elegant roots and median resistance to black-speck disease, has been harvested since 20 years. The percentage of Biantiao ginseng roots and yield were 15% and 30% higher than the control's respectively. The content of total ginsenosides and the main monomers was 1.8%-2.5% higher than the control's. The characteristics of overground part and root of BT1 were uniform and stable.

CONCLUSIONS

BT1, a new excellent ginseng variety, has a good potential value to be generalized in ginseng production.

Effects of storage temperature and fetal calf serum on the endothelium of porcine aortic valves

Endothelial integrity and function may be an important determinant for long-term success of allograft heart valves. To determine the optimal storage temperatures for preservation of long-term endothelial function in porcine aortic valves, different storage temperatures and times were investigated. Fresh valves were either (1) stored at 4 degrees C, with or without 10% fetal calf serum supplement, for 1, 2, 4, 7, 14, 21, or 28 days; (2) cryopreserved for 2, 4, or 8 weeks at -80 degrees C or -170 degrees C; (3) cryopreserved in long-term storage (as long as 1 year), with or without fetal calf serum, at -170 degrees C. Viability of endothelial cells was assessed through measurement of the production of prostacyclin in basal and bradykinin-stimulated conditions, during in vitro incubation of the valve cusps at 37 degrees C. Endothelial morphologic variations in valves stored at 4 degrees C were evaluated by scanning electron microscopy. With storage at 4 degrees C, after 4 days the valves already produced significantly less (p < 0.05) prostacyclin than fresh preparations in both basal (0.21 +/- 0.04 versus 3.56 +/- 0.03 ng.ml-1.cm-2) and stimulated conditions (4.17 +/- 0.36 vs 24.23 +/- 1.83). Morphologic changes could not yet be distinguished with scanning electron microscopy at that time. When the storage period was extended, the levels of prostacyclin further diminished; after 14 days, prostacyclin release could no longer be detected. In cryopreserved valves, prostacyclin production was similar for as long as 2 weeks of storage either at -80 degrees C or at -170 degrees C in basal (2.69 +/- 0.63 vs 2.93 +/- 0.51) and stimulated (16.43 +/- 3.19 vs 16.50 +/- 2.57, = 6) conditions. After 8 weeks, no prostacyclin release could be detected in valves stored at -80 degrees C. After 6 months storage at -170 degrees C, the prostacyclin production was significantly (p < 0.05) reduced compared with fresh valves; it then remained constant for as long as 1 year. The valves stored with fetal calf serum produced significantly (p < 0.05) less prostacyclin than did those without fetal calf serum. For longer cryopreserved banking, we recommend storing heart valves at -170 degrees C instead of at -80 degrees C to maintain viability of endothelial cells. Fetal calf serum would harm endothelial viability during long-term cryopreservation.

Thrombin triggers the de novo expression of an inducible NO synthase in porcine aortic valve endothelial cells

The nitric oxide (NO) production by porcine aortic valve endothelial cells was estimated in cusps incubated at 37 degrees C by measuring their cyclic GMP content and the nitrite levels of the incubation medium. After a stabilization period, incubation for 5 min with acetylcholine, bradykinin, ADP and bovine thrombin resulted in a receptor-mediated increase in cyclic GMP which could be blocked by EGTA, N-omega-nitro-L-arginine methyl ester (L-NAME) and NG-monomethyl-L-arginine (L-NMMA). Incubation with lipopolysaccharide (endotoxin) from E. coli O111:B4 or bovine for 5 h, dose-dependently increased nitrite production as well as cyclic GMP content. The elevated nitrite production was completely abolished in the presence of the protein synthesis inhibitor cycloheximide, was reduced by more than 50% by dexamethasone but was not affected by EGTA. L-NMMA dose-dependently reduced the increased nitrite production and cyclic GMP content. These results suggest that besides the presence of a constitutive NO synthase in porcine aortic valve endothelial cells thrombin, like lipopolysaccharide, triggers the de novo expression of an inducible Ca(2+)-independent NO synthase.

Effects of different antibiotics on the endothelium of the porcine aortic valve

Homograft heart valves are usually sterilized by exposure to multiple-antibiotic solutions at 4 degrees C for 24 hours. Several combinations of antibiotics have been proposed and discussed in the literature, but their toxicity to cusp endothelium has not been investigated yet. We studied the endothelial cell viability of porcine aortic valves by measuring their in vitro prostacyclin (PGI2) production after being exposed to different antibiotics solutions. Porcine aortic valves were immersed for 24 hours at 4 degrees C in RPMI medium to which antibiotics (Gentamycin 80 micrograms/ml, Azlocillin 500 micrograms/ml, Cloxacillin 25 micrograms/ml, Metronidazole 100 micrograms/ml, Amphotericin B 50 micrograms/ml, GACMA) were added separately or in combination. The basal and bradykinin (10 microM) stimulated PGI2 release of these valves in the medium were measured during consecutive incubation lasting 15 minutes at 37 degrees C, using a radioimmunoassay for 6-oxo-PGF1 alpha. Valves treated with the combination of all five antibiotics produced significantly less PGI2 in basal and stimulated conditions (1.64 +/- 0.63--7.25 +/- 1.73 ng/ml x cm2, p < 0.05) than the controls (4.66 +/- 0.66--30.55 +/- 3.84 ng/ml x cm2, p < 0.001). Although all antibiotics, when studied separately at the above mentioned concentrations, tended to reduce the biosynthesis of PGI2, amphotericin B was responsible for the most pronounced decrease in its production. The toxic effect of amphotericin B was dose dependent; at a low concentration (5 micrograms/ml), which is usually enough for antifungal action, toxicity was undetectable. At 50 micrograms/ml PGI2 production was half of that found at 5 micrograms/ml, although concentrations as high as 100 micrograms/ml have been used clinically to disinfect homografts. Scanning electron microscopy (SEM) also confirmed the extensive loss of endothelium after exposure to high concentrations of amphotericin B. Our study suggests that the other four antibiotics used in the concentrations described above do not damage endothelial function; amphotericin B is also harmless if used at a concentration of 5 micrograms/ml.

Improved endothelial viability of heart valves cryopreserved by a new technique

The aim of this study was to compare different techniques of aortic valve cryopreservation by studying the viability of the endothelial cells. Viability was assessed by measuring their in vitro prostacyclin (PGI2) production under basal and stimulated conditions. Fresh and cryopreserved porcine valves were incubated at 37 degrees C in tissue culture medium and PGI2 content in the medium was measured every 15 min up to 300 min. Cryopreservation by the older procedure A included 5% fetal calf serum (FCS) in the preservation medium, a plastic box inside a freezing plastic bag, a cooling schedule approximating -2 degrees C/min, a long thawing time and few dilution steps of the cryoprotectant dimethylsulphoxide (DMSO). The newer procedure B differed from A in packaging, freezing and thawing rates and DMSO dilution. Procedure C was similar to B with the exception that FCS was omitted. Leaflets preserved by procedure A produced significantly less prostacyclin as compared to those treated according to procedures B or C. We conclude that minor differences in the cryopreservation method can become critical to endothelial functional viability.