Study of recombinant human interleukin-12 for treatment of complications after radiotherapy for tumor patients

AIM To evaluate the treatment effects of recombinant human interleukin-12(rh IL-12) on radiotherapy complications, such as severe myelosuppression or pancytopenia, the decline or imbalance of immune function, etc.METHODS The patients received high-dose and short-course precise radiotherapy, such as Cyber knife and image-guided radiotherapy(IGRT), which can cause myelosuppression or pancytopenia and immune function decline within a short time. One-hundred subjects were enrolled in the study, and 50 were randomized to a treatment group which used rh IL-12 and 50 were randomized to a control group which used symptomatic and supportive therapy after radiotherapy. The 50 subjects in the treatment group were further divided into five subgroups and intervenedwith rh IL-12 at a dose of 50, 100, 150, 200 or 250 ng/kg respectively. The dose-effect relationship was observed. RESULTS Rh IL-12 significantly attenuated the decrease of peripheral blood cells in the treatment group, and immune function was improved after treatment. Due to the different radiation doses, there was a fluctuation within 12 h after treatment but mostly showing an increasing trend. As to the clinical manifestations, 2 patients in the 250 ng/kg subgroup showed low fever after administration, 1 patient in the 200 ng/kg subgroup and 2 patients in the 250 ng/kg subgroup showed mild impairment of liver function during the observation period.CONCLUSION Rh IL-12 has effective therapeutic and protective effects on complications following radiotherapy, such as the decline of blood cells, myelosuppression and the decline or imbalance of immune function, which indicated good prospects for development and application.

Enhancing production of a 24-membered ring macrolide compound by a marine bacterium using response surface methodology

A 24-membered ring macrolide compound,macrolactin A has potential applications in pharmaceuticals for its anti-infectious and antiviral activity.In this study,macrolactin A was produced by a marine bacterium,which was identified as Bacillus subtilis by 16S ribosomal RNA(rRNA) sequence analysis.Electrospray ionization mass spectrometry(ESI/MS) and nuclear magnetic resonance(NMR) spectroscopy analyses were used to characterize this compound.To improve the production,response surface methodology(RSM) involving Box-Behnken design(BBD) was employed.Faeces bombycis,the main by-product in sericulture,was used as a nitrogen source in fermentation.The interactions between three significant factors,F.bombycis,soluble starch,and(NH4)2SO4 were investigated.A quadratic model was constructed to fit the production and the factors.Optimum medium composition was obtained by analysis of the model.When cultivated in the optimum medium,the production of macrolactin A was increased to 851 mg/L,2.7 times as compared to the original.This study is also useful to find another way in utilizing F.bombycis.

High-level soluble expression of the hemA gene from Rhodobacter capsulatus and comparative study of its enzymatic properties

The Rhodobacter capsulatus hemA gene, which encodes 5-aminolevulinic acid synthase （ALAS）, was expressed in Escherichia coil Rosetta （DE3） and the enzymatic properties of the purified recombinant ALAS （RC-ALAS） were studied. Compared with ALASs encoded by hemA genes from Agrobacterium radiobacter（AR-ALAS） and Rhodobacter sphaeroides （RS-ALAS）, the specific activity of RC-ALAS reached 198.2 U/mg, which was about 31.2% and 69.5% higher than those of AR-ALAS （151.1 U/mg） and RS-ALAS （116.9 U/mg）, respectively. The optimum pH values and temperatures of the three above mentioned enzymes were all pH 7.5 and 37 ℃, respectively. Moreover, RC-ALAS was more sensitive to pH, while the other two were sensitive to temperature. The effects of metals, ethylene diamine tetraacetic acid （EDTA）, and sodium dodecyl sulfate （SDS） on the three ALASs were also investigated. The results indicate that they had the same effects on the activities of the three ALASs. SDS and metal ions such as Co^2＋, Zn^2＋, and Cu^2＋ strongly inhibited the activities of the ALASs, while Mn^2＋ exerted slight inhibition, and K^＋, Ca^2＋, Ba^2＋, Mg^2＋, or EDTA had no significant effect. The specificity constant of succinyl coenzyme A [（kcatlKm）^S-CoA] of RC-ALAS was 1.4989, which was higher than those of AR-ALAS （0.7456） and RS-ALAS （1.1699）, showing its high catalytic efficiency. The fed-batch fermentation was conducted using the recombinant strain containing the R. capsulatus hemA gene, and the yield of 5-aminolevulinic acid （ALA） achieved was 8.8 g/L （67 mmol/L） under the appropriate conditions.

Microencapsulated β-carotene preparation using different drying treatments

β-Carotene is one of the most abundant natural pigments in foods;however,usage of β-carotene is limited because of its instability.Microencapsulation techniques are usually applied to protect microencapsulated p-carotene from oxidization.In this study,β-carotene was microencapsulated using different drying processes:spray-drying,spray freeze-dryi ng,coati ng,and spray granulation.The properties of morphology,particle size,water con tent,thermal characteristic,and chemical stability have been explored and compared.Scanning electron microscopy measure?ments showed that the coated powder had a dense surface surro un ded by starch and suggested that the coati ng process gave a microencapsulated powder with the smallest bulk density and the best compressibility among the prepared powders.The chemical stabilities of microcapsules were evaluated during six months of storage at different temperatures.The coated powder had the highest mass fraction of β-carotene,which indicated that the coating process was superior to the three other drying processes.

Analysis of nicotine-induced metabolic changes in Blakeslea trispora by GC-MS

Blakeslea trispora is a natural source of carotenoids,includingβ-carotene and lycopene,which have industrial applications.Therefore,classical selective breeding techniques have been applied to generate strains with increased productivity,and microencapsulatedβ-carotene preparation has been used in food industry(Li et al.,2019).In B.trispora,lycopene is synthesized via the mevalonate pathway(Venkateshwaran et al.,2015).Lycopene cyclase,which is one of the key enzymes in this pathway,is a bifunctional enzyme that can catalyze the cyclization of lycopene to produceβ-carotene and exhibit phytoene synthase activity(He et al.,2017).

Succession law of Nd–Fe–B alloys with different coercivities

In order to establish a succession law of every phase in sintered Nd–Fe–B magnets marked as 38/38H/38SH/38 UH, four alloys of Nd33-xDyxAl0.7Nb0.6Cu0.1B1.05 Fe bal.(at%) were investigated after smelting processing, sintering processing, high-temperature tempering processing, and highand low-temperature tempering processing. It is found that the four phases: the Nd2Fe14B matrix phase, Nd-rich phase,B-rich phase, and defect phase can be inherited by means of the subsequent processing. These phases might have the special constitution and appearance in the different states.Magnetic properties also have succession law. In every processing except smelting one, the values of remanence and maximum energy product hardly alter, but the value of coercive force increases gradually.