Stimulation of low intensity ultrasound on fermentation of skim milk medium for yield of yoghurt peptides by Lactobacillus paracasei.

Herein the effect of low intensity ultrasound on the fermentation of skim milk medium by Lactobacillus paracasei were investigated to obtain optimum ultrasonic conditions for the highest yield of yoghurt peptides. The results showed that the fermented skim milk medium treated with ultrasound with its seed culture without ultrasonic treatment was an optimum scheme. In this scheme with the ultrasonic conditions of 28 kHz, ultrasonic pulsed model of on-time 100 s and off-time 10 s, 100 W/L for the treatment time of 30 min after the fermentation time of 9 h, the peptide content in the fermented skim milk media increased by 49.5% and the viable cells in the same media increased by 43.5% compared with those in the untreated samples. By response surface methodology (RSM) analysis and its verification experiments, a reasonably accurate empirical model was established for investigating and predicting the relationship between skim milk concentration, ultrasonic treatment time, power and the yield of yoghurt peptides. The former two parameters 12.6% w/v and 35 min were taken in the verification experiments in which the peptide content of the fermented media reached 5.9 mg/mL with an increase by 64.23% and the peptide yield was 14.2%, similar to its theoretical value of 14.6% according to the empirical model. The comparison of extracellular enzyme activities in the fermented skim milk media between with and without ultrasonic treatment under the conditions in the optimum scheme indicated that the mechanism of the ultrasound-activated peptide content increment might be the extracellular enzyme activities immediately activated by the ultrasound, effect of which would disappear in the progress of fermentation after the ultrasound was removed.

Ginsenoside improves papillary thyroid cancer cell malignancies partially through upregulating connexin 31.

Connexin 31 (Cx31) is considered a suppressor for many tumors. Ginsenoside (Rg1) is a traditional Chinese herb that is widely acknowledged due to its anti-tumor characteristics. However, limited studies have focused on the role of Rg1 in papillary thyroid cancer (PTC) cells. In the current study, we found that the expression of Cx31 in thyroid cancer tissues and thyroid cancer cell lines was significantly lower than that in normal thyroid epithelial tissues and cell lines. Overexpression of Cx31 reduced thyroid cancer cell proliferation, migration and invasion. Furthermore, we found that Rg1 significantly enhanced the expression of Cx31. Moreover, the proliferation and migration of IHH-4 and BCPAP cells were significantly reduced by Rg1 treatment. In contrast, the silencing of Cx31 enhanced the expression of Ki67 and proliferating cell nuclear antigen (PCNA). Meanwhile, treatment with Rg1 significantly decreased the protein levels of Ki67 and PCNA, but these effects could be abolished by transfection with si-Cx31. In summary, we provide novel evidence that the expression of Cx31 was decreased in thyroid cancer cells, but Rg1 treatment could significantly enhance the expression of Cx31 thereby suppressing thyroid cancer cell proliferation and migration.

Effects of ultrasound on microbial growth and enzyme activity.

Nowadays, ultrasound is widely used in many aspects. In the last few years, many papers have concentrated on the applications of ultrasound in engineering, chemistry, medicine, physics and biology, but few in biological effects such as the acceleration effects on proliferation of microbial cells, the inactivation effects on microorganisms and the influences on the activities of enzyme. Thus, the objective of this review is to investigate the biological effects of ultrasound on these aspects.

[Distribution of Bt protein in transgenic cotton soils].

A pot experiment with red soil, yellow brown soil, and yellow cinnamon soil was conducted to detect the Bt protein content in rhizosphere and non-rhizosphere soils at different growth stages of transgenic Bt cotton and common cotton by using enzyme linked immunosorbent assay (ELISA). With the planting of transgenic Bt cotton, the Bt protein content in rhizosphere soil was significantly higher than that in non-rhizosphere soil; while in common cotton soils, there was no significant difference in the Bt protein content between rhizosphere soil and non-rhizosphere soil. At bud stage of transgenic Bt cotton, the Bt protein content in rhizosphere soil was in the order of yellow cinnamon soil > yellow brown soil > red soil, being 144% 121%, and 238% of that in common cotton rhizosphere soil; at florescence stage of transgenic Bt cotton, the Bt protein content in rhizosphere soil was in the order of yellow brown soil > yellow cinnamon soil > red soil, being 156% , 116% , and 197% of that in common cotton rhizosphere soil, respectively. Regardless of planting Bt cotton or common cotton, the Bt protein content in rhizosphere and non-rhizosphere soils had an initial increase with the growth of cotton, peaked at florescence stage, and then decreased. Throughout the whole cotton growth period, the Bt protein content in transgenic Bt cotton rhizosphere soil was higher than that in Bt cotton non-rhizosphere soil, and also, higher than that in common cotton rhizosphere soil, indicating that transgenic Bt cotton could release its Bt protein to rhizosphere soil.

[Post antibiotic, post beta-lactamase inhibitor and post antibiotic sub-MIC effect of ceftriaxone/tazobactam on beta-lactamase-producing Escherichia coli in vitro].

OBJECTIVE: To study post antibiotic effect (PAE), post beta-lactamase inhibitor effect (PLIE) and post antibiotic sub-MIC effect (PASME) of ceftriaxone/tazobactam on beta-lactamase-producing Escherichia coli in vitro. METHODS: The minimal inhibitory concentration (MIC) of ceftriaxone/tazobactam against 4 types of beta-lactamase producing E. coli strains, was measured by two-fold agar dilution method. The numbers of CFU on plates were counted by micro-inoculation colony counting method. The growth kinetics curves of the bacteria were drawn according to CFU counts, from which the PAE, PLIE and PASME were calculated. RESULTS: The MIC of the ceftriaxone/tazobactam combination was eight times more than ceftriaxone alone. No longer PAE (-0.59-0.85 h) was found in the ceftriaxone/tazobactam combination or any of them alone. The PLIE and PASME varied according to the type of beta-lactamase but similar results were observed for the strains producing the same type beta-lactamase. All PLIEs (0.62-3.22 h) and most PASMEs (0.12-5.61 h) were longer than PAEs. The lower MIC of ceftriaxone the strain had, the longer the PAE, PLIE and PAMSE were. CONCLUSION: The duration of PLIE and PASME may concerned with the type of beta-lactamase. With both longer PLIE and PASME, longer dosing interval should be recommended. The PAE, PLIE and PASME provide an important instrument for pharmacodynamic studies of antibiotics, in particular for the design of dosing schedules.

Embryonic development of an insect sensory system, the abdominal cerci ofAcheta domesticus.

1. The embryonic development of the abdominal cerci of the house cricketAcheta domesticus is described from scanning and transmission electron microscope data. 2. A staged description of externally visible events in embryogenesis is tabulated as a context for describing the chronology of embryonic development of the abdominal cerci. 3. Three phases of cercal development are distinguished: differentiation of the cercal anlagen and secretion of the first embryonic cuticle; elongation of the cercus culminating in the secretion of the second embryonic cuticle after completion of a continuous epidermis at the time of dorsal closure; and differentiation of functional sensilla on the third embryonic (first instar) cuticle. 4. The first axon profiles appear in the cercus immediately before elongation of the cercus. These axons have dendrites with ciliary configuration in the lumen of the cercus. Glial cells associated with the pioneer axons may precede the axons in occupying dorsal and ventral luminal midlines of the cerci. 5. Trichoid sensilla appear in the integumet following apolysis of the second embryonic cuticle. 6. Axons are added to the dorsal and ventral pioneer fibre bundles shortly before sensilla become apparent. 7. The majority of sensory axons traverse the cercus during the final 15% of embryonic development. 8. The sensilla of the first instar cercus do not achieve their final orientation until the cercal cuticle is expanded following eclosion from the second embryonic cuticle that encloses the hatchling until it reaches a free surface. 9. The role of the pioneer fibres in establishing a pathway for the functional sensillar neurons is discussed in relation to other studies of sensillar development in insects.