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The present study investigated the three-dimensional spectra and emission spectra of the autofluorescence of rabbit hearts. The results suggested that the three-dimensional spectra of the iced atria and ventricle were observed more evidently different from that of the fresh tissue compared to the main artery, which indicated that the amount of flavins and NADHs changed. Also, the atria, ventricle and main artery have different specific excitation spectra at the wavelength of 340 nm. The main fluorescence peaks were of NADH (at about 460 nm), collagen and elastin (at about 290-400 nm). The Gauss spectra of atria and ventricle were different in the peak value, relative intensity and half width. So the ratios of fluorescence intensities of peaks may be used to distinguish different heart tissues. Furthermore, a phenomenon was firstly uncovered that the autofluorescence intensity of NADH in ventricle decays with the time of death and it could be a useful method for the estimation of postmortem interval.

The laser-inducted fluorescence spectrum technology (LIF) was used for the first time to study the autofluorescence spectral characteristics of the heart, kidney, liver, fat, foreleg muscle, hind leg soleus muscle and musculus gastrocnemius of the rat performing motion exercises. The wavelength of the excitation light used during the measurement was in the range of 250-650 nm and the emission wavelength was 300-700 nm. When comparing the three-dimensional fluorescence spectra of the control group with those of the four groups of different motion states, a specific fluorescence peak related to the motion and located in the area where the excitation wavelength was (340 +/- 10) nm and the emission wavelength was (460 +/- 10) nm was found mainly in the spectra of the soleus muscle. From this fluorescence peak, it is possible to determine that its corresponding fluorescent substance is NADH (nicotinamide adenine dinucleotide reduced). When comparing the fluorescence spectra of the four groups of different motion modes, it was found that the motion mode has a conspicuous relativity with the peak intensity. The results show that the energy metabolism of the soleus muscle of the rat in motion is stronger than that of the foreleg, soleus muscle and other visceras, and the autofluorescence spectral characteristics of NADH form one of the effective indexes for determining the muscular metabolism degree.

Recently, non-invasive optical methods to monitor transmembrane electrical potential using voltage sensitive dyes have been applied widely in the studies of normal and pathological heart rhythms and defibrillation. In the present paper, the authors measured the excitation and the emission spectra of the voltage-sensitive dyes di-4-ANEPPS bound to phospholipid bilayer membranes. And according to the spectral shift of di-4-ANEPPS, the authors presented an optical mapping system combining a DALSA CCD camera and a LED light source. Using this optical mapping system, the authors could record the action potential duration of the heart cells with high spatial and temporal resolutions. It can be a powerful tool in the study of cardiac arrhythmia mechanisms.

This study investigated the absorption spectrum and the fluorescence spectrum of rabbit hearts stained with the voltage sensitive dye (di-4-ANEPPS). The results suggested that the optical absorption of tissue with the dye was higher than that of the control group, and there were significant differences between the experimental group and control group in the range of 450-550 nm. It was also indicated that the maximum absorption peak of the dye in tissues was at (479.25 +/- 0.44) nm. Additionally, the different peaks of fluorescence emission spectra from the atriums, ventricles and aorta were originally found by testing the five parts of rabbit hearts with the dye. Their relative intensities were related to the distribution concentrations of the dye. Meanwhile, the peaks of excitation spectra and fluorescence emission spectra were determined by examining the three-dimensional and two-dimensional fluorescence spectra using ventricles and atriums with the dye. Based on the discrepancy of rest membrane voltages between ventricles and atriums, the best wavelength ranges of excitation light and emissions light of optical mapping were determined by the shifts of the dye in emission spectra with excitation at different wavelengths. These results offer a theoretical foundation for the design of a cardiac optical mapping system.

Microbial xylanases have received a great deal of attention in the last two decades for their potential applications in food, paper making and animal feed industries. Bacillus pumilus WL-11 was identified as a producer of alkane xylanase free of cellulase after screening soil samples of paper-making factories. The xylanase A (XylA) was purified to homogeneity from the culture filtrate of Bacillus pumilus WL-11 by (NH4) 2SO4 precipitation, CM-Sephadex and Sephadex G-75 chromatographies. The molecular mass of XylA is estimated to be 26.0 kD by SDS-PAGE and its isoelectric point is 9.5. The apparent Km is 16.6 mg/mL and V(max) is 1263 micromol/(min x mg) towards oat spelt xylan. XylA is optimally active between pH 7.2 and 8.0, and stable at pH 6.0 to 10.4. The enzyme is optimally active at 45 degrees C - 55 degrees C and stable at temperature below 45 degrees C, with its half time of activity of 35 min and 15 min at 55 degrees C and 60 degrees C respectively. HPLC analysis revealed that hydrolysis patterns of xylans from oat spelt, birch wood and beech wood by purified XylA were different. The XylA is determined to be an endo-beta-1,4-xylanase, as it generated mainly xylotriose and no xylose was detected among the three hydrolysates. XylA has strong hydrolytic activity towards the pentose in the hydrolysates of beech wood and birch wood xylans, but was not active to the pentose in the hydrolysate of oat spelt xylan. The crude WL-11 enzyme can efficiently hydrolyze oat spelt xylan to a series of xylo-oligosaccharides, suggesting its potential application in nutraceutical industry.

The psychrotrophs SYP-A2-3 producing the cold-adapted protease has been isolated from the bacterial samples collected from the No. 1 Glacier of China and identified as Bacillus cereus according to its morphological and physiochemical characteristics and 16s rDNA gene sequence analysis. It could grow between 0 degree C and 38 degrees C while its optimal growth temperature was 25 degrees C and the optimal temperature for its protease production was 15 degrees C. The cold-adapted protease was identified as neutral metallo-protease, the molecular weight was 34.2 kD shown by SDS-PAGE, the optimal pH and temperature for activity was 7.0-8.5 and 42 degrees C, respectively. Various fermentation conditions of its protease production were also investigated. The results showed that casein was the best nitrogen source while glucose and starch were suitable carbon source for its protease production. The initial pH of fermentation broth ranged from 6.5 to 7.0 was optimal. Under optimized conditions, the protease activity produced by SYP-A2-3 could reach 3800 U/mL and 4800 U/mL conducted in shaking flask and 5 L stirred jar experiment, respectively.

Aim: To study the stability of insulin-loaded polybutylcyanoacrylate nanoparticles (IPN) in an oily medium (soybean oil containing 0.5% (v/v) Tween-20 and 5% (v/v) Vitamin E) along with the hypoglycemic effect following their oral administration to streptozotocin (STZ) induced diabetic rats., Methods: The stability of IPN in the process was appraised by measurement of the amount of undegraded insulin associated to nanoparticles, the average size and the span of IPN, as well as the release of insulin from IPN. IPN in an aqueous medium (containing 0.5% (v/v) Tween-20) at pH 2.0 was also investigated as control., Results: The study showed that IPN in the oily medium was more stable than that in the aqueous medium over one year of storage in the dark at (25 +/- 2) degrees C and the in vitro stability of IPN in the oily medium against degradation by proteolytic enzymes was much better than that in the aqueous medium. The apparent bioavailability of an oral administration of IPN (50 u x kg(-1)) in the oily medium versus an (sc) injection of insulin (2 u x kg(-1)) was 22.4%, much higher than that of IPN in the aqueous medium (15.5%), based on decreased areas above curve (AAC) determination for the blood glucose depression from time zero to 144 h of a single oral administration of IPN to STZ-diabetic rats., Conclusion: IPN in soybean oil containing Tween-20 (0.5% v/v) and Vitamin E (5% v/v) could be considered as an effective and stable delivery system for oral insulin.

An alkaline catalase has been purified and characterized from a slightly halophilic and alkaliphilic bacterium Bacillus sp. F26. The purification was performed with a four step procedure consisting of ammonium sulfate precipitation, ion exchange, gel filtration and hydrophobic interaction chromatography, and finally achieved a 58.5-fold-purifying over the crude extract. The purified catalase was composed of two identical subunits with a native molecular mass of 140 kD. The native enzyme showed the typical Soret band appearing at 408 nm. The pyridine hemochrome spectrum indicated the presence of protoheme IX as the prosthetic group. The apparent Km value for enzyme activity on H2O2 was calculated to be 32.5 mmol/L. The activity of this catalase was not reduced by dithionite but was strongly inhibited by cyanide, azide, and 3-amino-1,2,4-triazole (the specific inhibitor of monofunctional catalase). No peroxidase activity of this enzyme was detected when using o-dianisidine, diaminobenzidine (DAB) and p-phenylenediamine as electron donor. Moreover, the N-terminal sequence of this catalase exhibited substantial similarity to the monofunctional catalase subgroup rather than catalase-peroxidase or Mn-catalase one. Therefore, we characterize the purified catalase as a monofunctional catalase. Besides, this monofunctional catalase was thermosensitive and its activity exhibited pH-independent over pH 5-9 but showed a sharp maximum at pH 11. An activity half-life of approximately 49 h was measured when the enzyme was incubated at 20 degrees C and pH 11. To our knowledge, pH 11 is the most alkaline condition for optimum catalysis and enzyme stability among the catalases reported up to now. Furthermore, this monofunctional catalase also showed excellent halo-alkali-stability with a half-life of approximately 90 h at 0.5 mol/L NaCl and pH 10.5. On the other hand, so far as we know, the characterized catalase is the first dimeric monofunctional catalase from alkaliphiles and is also the first monofunctional catalase derived from a natural soda lake, which could partially reflect the oxidative stress response in the corresponding environment.