Welcome to the 31st IUBS General Assembly and Conference on ...

improve its website <strong>and</strong> database quality which will
fur<strong>the</strong>r promote idea exchanges <strong>and</strong> accurate modeling
studies. BCGC will also improve public awareness about
its research output, which may help in <strong>the</strong> policy‐making
of governments for managing our biological resources.
BioonGroup
BioonGroup was established in
2001. Now it has become <strong>the</strong>
first Chinese media platform <strong>and</strong> professional service
provider of biological medicine industry. Relying on <strong>the</strong>
Internet, BioonGroup can provide consulting research,
industry analysis, br<strong>and</strong> packaging, product promotion,
human resources, conference planning <strong>and</strong>
comprehensive service system for enterprises,
research <strong>and</strong> development institutions, universities,
parks <strong>and</strong> <strong>the</strong> government of biological medicine
industry. BioonGroup contains six websites (for
example: www.bioon.com, www.bioon.com.cn,
www.pharmon.com.cn,
www.bioonjob.com,
www.bioinsight.com.cn, <strong>and</strong> www.bioevent.cn) <strong>and</strong>
core database of biological medicine industry, so we
can provide <strong>the</strong> leading, accurate, efficient service
systems <strong>and</strong> solutions.
Ceramide regulation of HA synthase
Jingdong QIN
University of Chicago, Rm C‐418, 5841 S Maryl<strong>and</strong> Ave, MC
4068, USA. Email: qjingdong@peds.bsd.uchicago.edu
Fibroblasts from <strong>the</strong> fro/fro mouse, with a deletion in <strong>the</strong>
Smpd3 gene coding for <strong>the</strong> active site of neutral
sphingomyelinase2 (NSMase2), secreted increased
amounts of hyaluronan (HA). This was reversed by
transfection with <strong>the</strong> Smpd3 gene, suggesting a
connection between sphingolipid <strong>and</strong> glycosaminoglycan
metabolism. The deficiency of NSMase2 resulted in
s<strong>to</strong>rage of sphingomyelin (SM) <strong>and</strong> cholesterol with a
50% reduction in ceramides (Cer). RT‐PCR <strong>and</strong> Western
blot analysis showed that <strong>the</strong> increased HA secretion
resulted from increased hyaluronan synthase 2 (HAS2)
activity localized <strong>to</strong> sphingolipid‐enriched lipid rafts.
Although cholesterol levels were also elevated in lipid rafts
from mouse fibroblasts deficient in lysosomal acid SMase
activity (deletion of <strong>the</strong> Smpd1‐/‐ gene), <strong>the</strong>re was no
increase in HA secretion. We <strong>the</strong>n showed that in fro/fro
fibroblasts, <strong>the</strong> reduced ceramide was associated with
decreased phosphorylation of protein phosphatase 2A
(PP2A) <strong>and</strong> increased phosphorylation of its substrate
Akt‐p, <strong>to</strong>ge<strong>the</strong>r with PI3K, PDK1, mTOR <strong>and</strong> p‐70S6K
whereas PTEN was unaffected. Exogenous ceramide, as
well as inhibi<strong>to</strong>rs of Akt (Akt inhibi<strong>to</strong>r VIII), PI3kinase
(LY294002 <strong>and</strong> wortmannin) <strong>and</strong> mTOR (rapamycin)
reduced secretion of HA whereas <strong>the</strong> NSMase2 inhibi<strong>to</strong>r
GW4869 increased HA syn<strong>the</strong>sis <strong>and</strong> secretion. We
propose that NSMase2/Cer are <strong>the</strong> key media<strong>to</strong>rs of <strong>the</strong>
regulation of HA syn<strong>the</strong>sis, via microdomains <strong>and</strong> <strong>the</strong>
Akt/mTOR pathway.
Characterization <strong>and</strong> functional
identification of vacuolar Na + /H + antiporter
from Nitraria sibirica Pall
Li WANG 1 ,Xiaofei LIN 1 , Huiping MAO 1
<strong>and</strong>Wenbo ZHANG 2
1College of Life Sciences, Inner Mongolia University, Hohhot
010021, China <strong>and</strong> 2College of Forestry, Inner Mongolia
Agricultural University, Hohhot 010019, China. Email:
linxiaofei04@hotmail.com
Vacuolar Na + /H + antiporters play an important role in
plants salt <strong>to</strong>lerance, which can deliver Na + in<strong>to</strong> <strong>the</strong>
vacuoles against <strong>the</strong> electrochemical gradient. The
compartmentation of Na + provides an effective
mechanism <strong>to</strong> avert <strong>the</strong> deleterious effects of Na + on
cy<strong>to</strong>sol, <strong>and</strong> maintain an osmotic potential by Na + in <strong>the</strong>
vacuoles. In this study, using <strong>the</strong> method of degenerate
PCR <strong>and</strong> rapid amplification of cDNA ends (RACE), an
ortholog of Na + /H + antiporter, referred <strong>to</strong> as NsNHX1,
was isolated from Nitraria sibirica Pall.
The cloned NsNHX1 cDNA contains 2182‐bp, with a
predicted ORF of 1635‐bp. The predicted NsNHX1 ORF
encodes a protein of 544 amino acids with 59.9 kDa of
<strong>the</strong>oretical molecular mass <strong>and</strong> 8.15 of isoelectric point.
The predicted amino acid sequence has an
amiloride‐binding motif <strong>and</strong> conserved domains as kefB,
CPA2, b‐cpa1, NhaP, etc. The phylogenetic analysis shows
that NsNHX1 forms a clade with <strong>the</strong> most closely related
plant NHX homologs, which was distinct from <strong>the</strong> cluster
of plasma membrane Na + /H + antiporters such as AtSOS1,
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