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21 results on '"Liu, Nanjun"'

18. Spinal pathomorphological changes in the breeding giant salamander juveniles.

Author

Chen, Jindong, Liu, Nanjun, Li, Xueying, Niu, Jing, and Wang, Dazhong

Subjects
*SALAMANDERS, *ANIMAL breeding, *SCOLIOSIS, *BONE density, *ENDANGERED species
Abstract

The Chinese giant salamander ( Andrias davidianus, Blanchard, 1871) is the largest amphibian on earth. While the number of the wild Chinese giant salamanders is declining and becoming a rare endangered species, breeding of giant salamander in China has launched since 1980s. However, scoliosis often occurs in the breeding giant salamander juveniles. To explore the pathomorphological changes and bone mineral density of the morbid breeding giant salamander, molybdenum-rhodium target X-ray photography and conventional histopathological analysis have been adopted to investigate the disease occurred in affected salamander juveniles. Vertebra, spinal core, vertebral foramen, paravertebral skeletal muscle, and other related parts were examined. The results showed that the bone mineral density in the body-curved giant salamander juveniles is significant lower compared to the peer normal controls ( p > 0.05). In addition, spinal cord, spine, and its surrounding muscles were deformed in the diseased salamander. [ABSTRACT FROM AUTHOR]

Published
2016
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20. Chemical Approaches to Understand the On-Membrane Action of Magainin 2

Author

Liu, Nanjun (Liu, Nanjun)

Subjects
Antibiotics, Antimicrobial peptides, Mechanism, Selectivity
Abstract

There is substantial interest in exploring antibiotic alternatives with a new mode of action due to the increasing rates of bacterial resistance against current antibiotics. Antimicrobial peptides (AMPs) may take up the battle against bacteria in the future because as a result of their membrane-lysis mechanism, it is more difficult for bacteria to develop resistance against AMPs. Although AMPs could preferentially bind to and disrupt negatively charged bacterial membranes through electrostatic and hydrophobic interactions, there is still a great need to further increase the potency and selective toxicity towards bacteria for clinical applications. Herein, we present two strategies to improve the selectivity: light activation and environment-responsive moiety incorporation. Along the way, we also explored the effect of structure stabilization on AMPs action. A well-characterized antimicrobial peptide magainin 2 (mag2) was used as a prototype. Chemical manipulations of mag2 sequence were achieved by incorporation of unnatural amino acids. The selectivity was then tested on liposomes as a membrane model, as well as on bacterial cells and human red blood cells (hRBCs). Different extents of selectivity enhancement were observed from the modified peptides, and within the attempts to illustrate these results, we have gained useful information revealing the membrane-lysis mechanism, which may help us to rationally design and engineer AMPs as therapeutic drugs in the future.

Published
2011

21. Establishment of a Mouse Asthenospermia Model through Triggering D-Galactose Mediated Oxidative Stress Injury.

Author

Liu N, Wang Q, Li L, and Lu J

Subjects
Animals, Asthenozoospermia chemically induced, Asthenozoospermia metabolism, Asthenozoospermia pathology, Galactose, Humans, Male, Malondialdehyde metabolism, Mice, Oxidative Stress drug effects, Semen Analysis, Spermatozoa drug effects, Spermatozoa metabolism, Testis drug effects, Testis metabolism, Asthenozoospermia etiology, Disease Models, Animal, Oxidative Stress physiology
Abstract

Background: Asthenospermia is defined as the forward motility of sperm less than 32%., Aim/objective: This study aimed to establish a mouse model of asthenospermia through triggering D-galactose mediated oxidative stress., Methods: A total of 40 Kunming male mice were randomly divided into control group, low-dose group (administrating D-galactose at 60 mg/kg), high-dose group (administrating D-galactose at 120 mg/kg), and high-dose+feed addition group (administrating D-galactose at 120 mg/kg together with oral D-galactose). The testicular weight, testicular organ coefficient, sperm viability, sperm concentration, and survival rate of the tail of epididymis were measured. Oxidative damage of D-- galactose to the reproductive system of mice was evaluated by measuring superoxide dismutase (SOD) and malondialdehyde (MDA) in the testicular homogenate of mice., Results: The sperm motility, motility rate, concentration, and survival rate of low-dose, high-dose and high-dose+feed addition group were decreased, compared to that in the control group. However, there background:was a significant difference between high-dose group/high dose+feed group and the control group (p<0.05): the forward motile sperm motility rate and total motility rate are accorded with critical criteria of asthenospermia. As compared with the control group, the activity of SOD of model group mice significantly decreased, and MDA concentration significantly increased (p<0.05), except for low-dose versus control group for SOD activity. This suggests that testicular tissues suffered from oxidative damage., Conclusion: This study successfully established a mouse asthenospermia model through D-galactose mediated oxidative stress injury. The establishment of asthenospermia model in this study would provide new promising insight and act as a potential approach for studying asthenospermia in vivo levels., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Published
2021
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