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conditions of C. megacephala protein. Optimization
fac<strong>to</strong>rs were enzyme dosage (5–7%), level of water added
(20–30 mL/g), pH (8–9) <strong>and</strong> temperature (50–60℃)
while investigated response was <strong>the</strong> degree of hydrolysis
(DH%). An optimal design, with 4 variables <strong>and</strong> one
response function, was employed <strong>to</strong> study <strong>the</strong> effect of <strong>the</strong>
individual variables on <strong>the</strong> response function. For each
response, second‐order polynomial models were
developed using multiple linear regression analysis. The
degree of hydrolysis was significantly affected by <strong>the</strong>
enzyme dosage, pH <strong>and</strong> temperature. Applying
desirability function method, optimum hydrolysis
operating conditions were found <strong>to</strong> be enzyme dosage of
7%, level of water added of 25 mL/g, pH of 9.0 <strong>and</strong>
temperature of 59.87℃. At this optimum point, <strong>the</strong> actual
degree of hydrolysis was found <strong>to</strong> be 23.30%, <strong>and</strong> <strong>the</strong>
predicted value 22.66%. The results presented in this
work show a fast, simple <strong>and</strong> easy enzymatic hydrolysis
process of C. megacephala protein.
Patterns determinants <strong>and</strong>conservation of
vascular plants on <strong>the</strong> Tibetan Plateau
Yujing YAN <strong>and</strong> Zhiyao TANG
Department of Ecology, College of Urban <strong>and</strong> Environmental
Science, Peking University, Beijing 100871, China. Email:
africarugu@gmail.com
Large‐scale patter of species richness <strong>and</strong> its
determinants have long been <strong>the</strong> central issues in
biogeography <strong>and</strong> macroecology. The Tibetan Plateau is
<strong>the</strong> highest plateau in <strong>the</strong> world; it provides habitats for
about 8000 vascular plants, of which about 17% are
endemic <strong>to</strong> <strong>the</strong> plateau. The plateau is undergoing
remarkable climate change. To underst<strong>and</strong> <strong>the</strong> response
of ecosystems <strong>to</strong> climate change on <strong>the</strong> Tibetan Plateau, it
is <strong>the</strong>refore necessary <strong>to</strong> explore <strong>the</strong> patterns <strong>and</strong> <strong>the</strong>
fac<strong>to</strong>rs determine <strong>the</strong>se patterns of <strong>the</strong> biodiversity. Here,
we studied patterns of richness of <strong>the</strong> vascular plant,
based on a high resolution distribution database of
vascular plants. The results show that most of <strong>the</strong> vascular
plants are distributed on <strong>the</strong> eastern part of <strong>the</strong> plateau
<strong>and</strong> in <strong>the</strong> main mountain areas, while <strong>the</strong> species
endemic <strong>to</strong> <strong>the</strong> Tibetan Plateau are mostly distributed
along <strong>the</strong> HimalayaMountains. The complimentary
algorithm revealed that ‘hotspots’ of endemic plants are
mainly located in <strong>the</strong> sou<strong>the</strong>astern part of <strong>the</strong> plateau.
Moreover, an area occupies approximately 20% of <strong>the</strong>
plateau could cover all <strong>the</strong> species endemic <strong>to</strong> <strong>the</strong> plateau.
The annual precipitation <strong>and</strong> mean temperature of <strong>the</strong>
coldest month are <strong>the</strong> fac<strong>to</strong>res in shaping <strong>the</strong>se patterns;
whereas <strong>the</strong> habitat hererogeneity played no significant
role in determing this pattern.
Population dynamics <strong>and</strong> invasive his<strong>to</strong>ry of
red swamp crayfish (Procambarus Clarkii)
Lijun HE 1,2 <strong>and</strong> Min CHAO 2
1State Key Labora<strong>to</strong>ry of Estuarine <strong>and</strong> Coastal Research, East
China Normal University, Shanghai 200062 China <strong>and</strong> 2 East
China Sea Fisheries Research Institute, Chinese Academy of
Fishery Sciences, Shanghai200090, China. Email:
tiger02j@hotmail.com
Since <strong>the</strong> 1900s, human activities have increased
opportunities for biological invasion <strong>and</strong> caused some
severe economic <strong>and</strong> ecological questions in <strong>the</strong>
terrestrial ecosystem. In China, red swamp crayfish
(Procambarusclarkii) is an economically important
aquatic invasive species. This species has quickly
exp<strong>and</strong>ed <strong>to</strong> almost <strong>the</strong> entire drainage of Yangtze River
through human‐mediated translocations or natural
migrations since <strong>the</strong>ir first introduction. To elucidate <strong>the</strong>
genetic diversity <strong>and</strong> population origin of this introduced
crayfish, we obtained samples from 8 sites in China <strong>and</strong> 2
sites in native USA. Segment of mi<strong>to</strong>chondrial
cy<strong>to</strong>chrome oxidase subunit I gene (COI) was amplified,
<strong>and</strong> some DNA sequences from o<strong>the</strong>r native population in
North America <strong>and</strong> alien population in Europe were also
downloaded from GenBank. A star‐like tree <strong>and</strong> shallow
intraspecific divergence indicate recent population
expansion in native North America. Relative <strong>to</strong> <strong>the</strong>
native population in USA <strong>and</strong> Mexico, genetic bottleneck
<strong>and</strong> reduced genetic variation were revealed from
populations in European <strong>and</strong> China. Two of 3 European
haplotypes were shared by Louisiana samples, which
supports <strong>the</strong> records that P. Clarkii was first introduced
from Louisiana <strong>to</strong> Spain in 1973. Only 2 haplotypes
occurred in <strong>the</strong> Chinese samples. One of <strong>the</strong>m was shared
by a dominant <strong>and</strong> central haplotype from Louisiana, <strong>the</strong>
o<strong>the</strong>r was shared by a terminal haplotype from
nor<strong>the</strong>astern Mexico, which likely provide direct evidence
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