Recombinant Snail Sialic Acid Aldolase is Promiscuous towards Aliphatic Aldehydes.

Aldolases are enzymes that reversibly catalyze the cleavage of carbon-carbon bonds. Here we describe a recombinant sialic acid aldolase originating from the freshwater snail Biomphalaria glabrata (sNPL), and compare its substrate spectrum with a sialic acid aldolase originating from chicken (chNPL). In contrast to vertebrate animals which can synthesize, degrade, and incorporate sialic acids on glycoconjugate ubiquitously, snails (as all mollusks) cannot synthesize sialic acids endogenously, and therefore the biological function and substrate scope of sNPL ought to differ significantly from vertebrate sialic aldolases such as chNPL. sNPL was active towards a series of sialic acid derivatives but was in contrast to chNPL unable to catalyze the cleavage of N-acetylneuraminic acid into N-acetylmannosamine and pyruvate. Interestingly, chNPL and sNPL showed contrasting C4(R)/(S) diastereoselectivity towards the substrates d-mannose and d-galactose in the presence of pyruvate. In addition, sNPL was able to synthesize a series of 4-hydroxy-2-oxoates using the corresponding aliphatic aldehyde substrates in the presence of pyruvate, which could be not achieved by chNPL.

Effect of Acupuncture on Ovary Morphology and Function in DHEA-Induced Polycystic Ovary Syndrome Model Rats.

OBJECTIVE: To investigate the effects of acupuncture on ovary morphology and function in dehydroepiandrosterone (DHEA)-induced polycystic ovary syndrome (PCOS) model rats. METHODS: A total of 40 adult female Wistar rats were randomly allocated to 4 groups by a random number table, including control, model, metformin and acupuncture groups, 10 rats in each group. PCOS rat model was developed by injecting with DHEA (6 mg/100 g body weight) in 0.2 mL of oil subcutaneously. Electrical stimulation (2 Hz, 3 mA) was applied to Guanyuan (CV 4), Zigong (EX-CA1) and Qihai (CV 6) acupoints for 30 min daily in the acupuncture group, and metformin (200 mg/kg) was given to rats in the metformin group, both once per day for 21 consecutive days, and rats in the normal group was fed with normal saline and fed regularly. After 21 days of administration, the rat blood samples were collected for detecting the reproductive hormonal levels [luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol (E2), progesterone (P), testosterone (T)] and inflammatory factors (visfatin, IL-6) analysis. Ovary tissue was used for histopathological analysis. RESULTS: Compared with the model group, rats in the acupuncture and metformin groups were significantly lower in weight gain, FSH, LH and T levels, and E2 and P levels significantly increased (alll P<0.05). Meanwhile, LH and FSH levels were significantly decreased, and P, T and E2 levels significantly increased in the acupuncture group, compared with the metformin group (P<0.05). Compared with the model group, IL-6 and visfatin levels were significantly decreased in the acupuncture and metformin groups (P<0.05). There were no significant differences in IL-6 and visfatin levels between the acupuncture and metformin groups (P>0.05). Ovarian diameter in the acupuncture and metformin groups were smaller than the model group (P<0.05). However, there were no significant differences in ovarian diameters between the acupuncture and metformin groups (P>0.05). CONCLUSION: Acupuncture might improve ovary morphology and its function in DHEA-induced PCOS model rats.