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

consumption of crustaceans. To explore how Cd affects
<strong>the</strong> oxygen consumption of freshwater crab Sinopotamon
henanense, <strong>the</strong> crabs were exposed <strong>to</strong> 0.71, 1.42,
2.86mg/L Cd for three weeks. The oxygen consumption,
gill morphological changes, cardiac metabolism activity
(activity of isocitrate dehydrogenase (IDH) <strong>and</strong>
cy<strong>to</strong>chrome c oxidase (CCO), mRNA expression of CCO
active subunit 1 (cco­1)), cardiomyocyte ultrastructure
changes <strong>and</strong> ATP level were investigated. After exposure,
oxygen consumption was decreased at 2.86mg/L, which
partly resulted from profound gill structural changes. The
branchial epi<strong>the</strong>lial cells were necrosed, disorganized <strong>and</strong>
vacuolized. Ultrastructurally, decreased number of apical
microvilli, vacuolized mi<strong>to</strong>chondria <strong>and</strong> condensed
chromatin in gill epi<strong>the</strong>lial cells were observed. Cd
exposure also induced decreased IDH <strong>and</strong> CCO activity,
down‐regulation of cco­1 mRNA expression with <strong>the</strong> loss
of cardiomyocyte mi<strong>to</strong>chondrial membrane integrity,
suggesting <strong>the</strong> impaired cardiac metabolism activity.
Heart ATP level was lower than that in control. By
coupling morphological <strong>to</strong> physiological <strong>and</strong> biochemical
endpoints, this work provides new insights in<strong>to</strong> <strong>the</strong>
mechanisms involved in metal <strong>to</strong>xicity <strong>and</strong> metabolism
impairment of S. henanenseexposed <strong>to</strong> Cd.
How rapid was <strong>the</strong> biggest biological mass
extinction during <strong>the</strong> Phanerozoic?
Permian‐Triassic boundary. To better constrain <strong>the</strong>
timing, <strong>and</strong> ultimately <strong>the</strong> causes of this event, we
collected a suite of geochronologic, iso<strong>to</strong>pic <strong>and</strong>
biostratigraphic data on tens of well‐preserved
Permian‐Triassic sections in South China <strong>and</strong> <strong>the</strong>
peri‐Gondwanan region. High‐precision U‐Pb dating
based on 29 volcanic ash layers <strong>and</strong> biodiversity pattern
pooled occurrence data of 4500 species in a large
geographic area reveal that <strong>the</strong> extinction interval was
less than 200000 years, <strong>and</strong> <strong>the</strong> extinction peak
occurred just before 252.28+/‐0.08 Ma <strong>and</strong> coincided
with a d13C excursion of about ‐5‰. It was
synchronous in marine <strong>and</strong> terrestrial realms;
associated charcoal‐rich <strong>and</strong> soot‐bearing layers
indicate widespread wildfires on l<strong>and</strong>. The
end‐Guadalupian biological crisis was ano<strong>the</strong>r less
pronounced event separated by a high‐diversity
interval more than 7 millions years long from <strong>the</strong>
end‐Permian mass extinction.
How <strong>to</strong> promote longevity: let H 2 S count <strong>the</strong>
way
Guangdong YANG
School of Kinesiology, Lakehead University, Canada. Email:
gyang@lakeheadu.ca
Shuzhong SHEN
Nanjing Institute of Geology <strong>and</strong> Palaeon<strong>to</strong>logy, 39 East Beijing
Road, Nanjing, Jiangsu 210008, China. Email:
szshen@nigpas.ac.cn
The end‐Permian mass extinction has been universally
documented as <strong>the</strong> biggest extinction during <strong>the</strong>
Phanerozoic <strong>and</strong> resulted in <strong>the</strong> extinction of 95%
marine species <strong>and</strong> 75% terrestrial species. In <strong>the</strong>
immediate aftermath <strong>the</strong> marine ecosystem was
prevailed by microbial <strong>and</strong> mono<strong>to</strong>nous communities
dominated by disaster taxa, <strong>and</strong> <strong>the</strong> whole recovery <strong>to</strong> <strong>the</strong>
pre‐extinction level <strong>to</strong>ok more than 5 million years.
Although it is <strong>the</strong> most intensively‐studied event, its
causes <strong>and</strong> patterns remain contentious yet. It has been
documented that <strong>the</strong> end‐Permian mass extinction was a
protracted event beginning from <strong>the</strong> end‐Guadalupian
about 8 million years before <strong>the</strong> end of Permian. By
contrast, some o<strong>the</strong>rs suggested that this event happened
within a very short time beginning just before <strong>the</strong>
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H 2 S, <strong>the</strong> third member of <strong>the</strong> gasotransmitter family
along with nitric oxide <strong>and</strong> carbon monoxide, exerts a
wide range of actions in our body. H 2 S can be
endogenously produced by cystathionine gamma‐lyase
(CSE) <strong>and</strong> cystathionine beta‐synthase (CBS), <strong>and</strong> one
of <strong>the</strong> signaling mechanisms of H 2 S is post‐translational
modification of proteins through S‐sulfhydration.
Aging at <strong>the</strong> cellular level, known as cellular senescence,
can result from increases in oxidative stress. Here we
showed that mouse embryonic fibroblasts isolated from
CSE knockout mice (KO‐MEFs) displayed increased
oxidative stress <strong>and</strong> cellular senescence in comparison
with MEFs from wild‐type mice (WT‐MEFs) in a
passage‐dependent manner. Incubation of <strong>the</strong> cells
with NaHS (a well‐known H 2 S donor) significantly
increased glutathione level <strong>and</strong> rescued KO‐MEFs from
senescence. Short interfering‐mediated knockdown of
CBS also stimulated cell.