Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf...
-
Upload
kameron-tilley -
Category
Documents
-
view
214 -
download
2
Transcript of Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf...
![Page 1: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/1.jpg)
Hypoxia: Hypoxia: Problems and Scientific ChallengesProblems and Scientific Challenges
Prof. Rudolf WuSchool of Biological SciencesThe University of Hong Kong
![Page 2: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/2.jpg)
Hypoxia: An Old Problem with New Insights
![Page 3: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/3.jpg)
Hypoxia: TrendHypoxia: Trend
During the last few decades, anthropogenic input of nutrients into our coastal environment has increased ca. three folds, and is expected to double or triple if no action is taken
![Page 4: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/4.jpg)
Hypoxia: TrendHypoxia: Trend
Decrease in dissolved oxygen recorded over large coastal areas worldwide (including USA, China, Norway, UK, Sweden, Germany, Denmark, the Black Sea, Adriatic Seas) in the last 30-80 years
Diaz & Rosenberg, 1995; Rabalais, 2001
![Page 5: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/5.jpg)
Total area>245,000 km2
![Page 6: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/6.jpg)
Number of Dead Zones doubled Number of Dead Zones doubled
every 10 years since the 1960severy 10 years since the 1960s
Diaz & Rosenberg, 2008
![Page 7: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/7.jpg)
Hypoxia Has Caused Major Changes in Hypoxia Has Caused Major Changes in Structure and Functions of EcosystemsStructure and Functions of Ecosystems
– Mass mortality of fish and benthos – Changes in species composition– Changes in trophic relationships– Decrease in biodiversity and species
richness– Decrease in fisheries production
Phil, 1994; Wu, 2002; Gray et al., 2002Wu, 2002; Gray et al., 2002
![Page 8: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/8.jpg)
Normoxia Hypoxia
Diversity, Species richnessDemersal fishLarger body sizePredator
Suspended feeders
Deposit feedersMeiofauna, NanoplanktonPelagic fishShort life cycle
Generalized Changes in Structure Generalized Changes in Structure and Functions of Ecosystemsand Functions of Ecosystems
Wu, 2002
![Page 9: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/9.jpg)
New Scientific EvidenceNew Scientific Evidence
further show that…..further show that…..
![Page 10: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/10.jpg)
Hypoxia is Hypoxia is an endocrine disruptoran endocrine disruptor
Common carp (Cyprinus carpio)
![Page 11: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/11.jpg)
MaleMale
0
0.1
0.2
0.3
7.0 mg/L
1.0 mg/L
***
(ng/ml)
** p<0.01; *** p<0.001
Wu et al, 2003
0
1
2
3
4
5
6
7
8
9
10
7.0 mg/L
1.0 mg/L
EstradiolEstradiolTestosteroneTestosterone
**
![Page 12: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/12.jpg)
Female Female
0
2
4
6
8
10
Testosterone Estradiol
7.0 mg/L
1.0 mg/L
*** *
(ng/ml)
* p<0.05; *** p<0.001
Wu et al, 2003
![Page 13: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/13.jpg)
• Gonadal
development
• Gametogenesis
• Spawning
• Fecundity
Hypoxia impairs fish reproductionHypoxia impairs fish reproduction
• Fertility
• Gamete quality
• Offspring survival
• Reproductive behavior
Common carp
(Wu et al. 2003)
Zebrafish
(Shang et al. 2006)
Atlantic croaker
(Thomas et al. 2006,2007)
Gulf killifish
(Landry et al. 2007)
![Page 14: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/14.jpg)
Sperm MotilitySperm Motility
0
10
20
30
40
50
60
70
80
7 mg/L
1 mg/L
Curvilinearvelocity
StraightLine velocity
ActualPath velocity
*
*
*
* p < 0.05
µmS-1
Wu et al, 2003
![Page 15: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/15.jpg)
Reproductive ImpairmentReproductive Impairment
0
10
20
30
40
50
60
70
80
90
100
7 mg/L
1 mg/L
Fertilization Hatching LarvalSurvival
Egg to Larvae
***
***
***
***
*** p < 0.001
%
Wu et al, 2003
![Page 16: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/16.jpg)
Follow-up questions: What caused the Follow-up questions: What caused the observed endocrine disruption?observed endocrine disruption?
• A smaller gonad and reduced hormone production due to reduced energy intake and reduced growth?
• Hypoxia affects synthesis and metabolism of sex hormones?
• Hypoxia affects GnRH and gonadotropins?
![Page 17: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/17.jpg)
In vitroIn vitro evidence evidence
• In vitro studies using H295R human adrenocortical carcinoma cell line and primary cell culture of medaka gonads
![Page 18: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/18.jpg)
Cholesterol
CYP11A
Pregnenolone
3β-HSD
Progesterone
CYP21
11-Deoxy-corticosterone
CYP11B1
Corticosterone
CYP11B2
Aldosterone
CYP17
17α-OH-
Pregnenolone
3β-HSDCYP17
17α-OH-
Progesterone
CYP21
11-Deoxycortisol
CYP11B1
Cortisol
CYP17
DHEA
3β-HSDCYP17
Androstene-dione
17β-HSD
Testosterone
CYP19
17β-Estradiol
Zona glomerulosaZona fasciculata
Zona reticularis
StAR
![Page 19: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/19.jpg)
Hypoxia is a teratogenHypoxia is a teratogen
Zebrafish (Danio rerio)
![Page 20: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/20.jpg)
Hypoxia delays developmentHypoxia delays development24hpf
Control
Hypoxia (0.5mg/l)
48hpf
Shang & Wu, 2004
![Page 21: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/21.jpg)
Hypoxia caused spine and cardiac malformationsHypoxia caused spine and cardiac malformations
Shang & Wu, 2004
Mal
form
atio
n (
%)
Time (hour)
* p < 0.05; ** p < 0.01
5.8 mg/L0.8 mg/L* **
**
![Page 22: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/22.jpg)
Under hypoxia, apoptosis concentrates in the head Under hypoxia, apoptosis concentrates in the head but not the tailbut not the tail
Control Hypoxia
Shang & Wu, 2004
![Page 23: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/23.jpg)
Sex differentiation/
reversal completed
Final maturation
of the gonads
Gonads differentiate into ovaries
SpawningSex
differentiation begins
3-HSD (-)CYP11A (-)
CYP19A (ND)CYP19B (-)
3-HSD (-)CYP11A (-) CYP19A (-)CYP19B (-)
Male3-HSD (-)CYP11A (-)CYP19A (+)CYP19B (+)
T/E2 (NC)
Male3-HSD (-)CYP11A (-)CYP19A (-)
CYP19B (NC)T/E2 (NC)
Female 3-HSD (+)CYP11A (-)CYP19A (+)CYP19B (+)
T/E2 (+)
Female 3-HSD (-)CYP11A (-)CYP19A (+)
CYP19B (NC)T/E2 (+)
(C) 60 dpf (D) 120 dpf
(B) 40 dpf (A) 10 dpf
10-12 dpf 23-25 dpf 42 dpf 60 dpf 120 dpf
Juvenile AdultLarval 3 dpf 90 dpf 30 dpf
Shang et al, 2006
![Page 24: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/24.jpg)
Hypoxia tips sex balance & Hypoxia tips sex balance & favors a male biased populationfavors a male biased population
***
*** p < 0.001
Shang, Yu & Wu, 2006
![Page 25: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/25.jpg)
Where the girls are? Where the girls are?
Will this affect reproductive success of Will this affect reproductive success of the natural population?the natural population?
![Page 26: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/26.jpg)
Is the observed male biased Is the observed male biased phenotypic or geneotypic?phenotypic or geneotypic?
Will the same happens to Will the same happens to species with XY species with XY chromosomes?chromosomes?
![Page 27: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/27.jpg)
Phenotypic & Phenotypic & gonadal Sex in genotypic onadal Sex in genotypic females (females (O. latipes)O. latipes) are altered by are altered by hypoxiahypoxia
Cheung, 2006; Wu, 2009
![Page 28: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/28.jpg)
Will the same occur in higher vertebrates?
• Salamanders (Ambystoma sp.): delayed development and hatching, less developed and deformed embryos
• Australian frog (Crinia georgiana): delayed embryonic development, increased malformation
• Male albino rats: reduced numbers of sertoli cells and Leydig cells in testis
• Male Wistar rats: lower levels of LH and testosterone
Seymonr et al., 2000; Shevantaeva & Kosyuga, 2006; Farias et al., 2007
![Page 29: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/29.jpg)
Wu & Orr, 2005
7.50 4.50 3.500
20
40
60
80
100
A
% c
op
ula
tion
***
7.50 4.50 3.500
2
4
6
8
10
B
No
.of o
ffsp
rin
g
***
7.50 4.50 3.500.0
0.5
1.0
C
Dissolved oxygen (mg O2 L-1)
No
. of b
roo
ds
***7.50 4.50 3.50
0
10
20
30
40
50
***
D
Dissolved oxygen (mg O2 L-1)
Fec
un
dity
*** p<0.005
Methyl farnesoate?
Ecdysteroid?
Will the same occur in invertebrates?
![Page 30: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/30.jpg)
Is the situation getting better or getting worse?
![Page 31: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/31.jpg)
The situation is likely to get worse because…..
• Growth of treatment facilities is unlikely to catch up with growth of population and industry, especially in developing counties
• Contributions from atmospheric fallout and non-point source are significant
• Trans-boundary issues are difficult to resolve
![Page 32: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/32.jpg)
Increase TemperatureIncrease freshwater input
Increase nutrient flux Increase stratification
Nutrient enrichmentEnhanced productivity
Global Warming
HypoxiaSediment
Increase metabolic rate
![Page 33: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/33.jpg)
Risk Assessment• Ecological consequence Very serious
• Area affected Very large
• Socioeconomic loss Very big
• No. people affected Very large
• Probability of occurrence Very high
• Trend Getting worse
The new scientific evidence presented here calls for an urgent re-assessment of this old problem
![Page 34: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/34.jpg)
![Page 35: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/35.jpg)
Will the same happen in humans?
• Patients suffering from sleeping apnea have lower sex drive and testosterone level (Saaresranta & Polo, 2003)
• Sex ratio in human depends on level of sex hormones of father and mother during conception, and high testosterone level during conception favors subsequent birth of sons (James, 2004)
![Page 36: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/36.jpg)
Brain
Pituitary
Ovary
Blood
sGnRH
FSH
LH
(+)
(+) FSH-R
HMGR
(-)
(-)Progestin ?
(+)?
Summary of effects of hypoxia on The HPG axis in female zebrafish
ER
GnRH FSH CYP19A E2
CYP19A
E2(+)(+)
(+)
![Page 37: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/37.jpg)
Proposed WorkCollaborate with fisheries authorities and undertake a scientific global review, focusing on :
– Trend analysis (spatial and level in the last 50 years)
– Changes in structure and trophodynamics of marine communities (plankton, benthos, fish)
– Identification of sensitive groups (bioindicators)
![Page 38: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/38.jpg)
Proposed WorkCollaborate with fisheries authorities and undertake a scientific global review, focusing on :
– Reproductive status and reproductive impairment of fish in hypoxic areas vs normoxic areas
– Endocrine disruption, malformation, sex ratio
– Deciphering effects of hypoxia from those caused by other anthropogenic activities (chemicals) prevailing simultaneously in the marine environment??
– Identifying information gaps and further studies
![Page 39: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/39.jpg)
Hypoxia affects spermatogenesisHypoxia affects spermatogenesis
Normoxia Hypoxia
** p < 0.01; *** p < 0.001
0
1
2
3
4
5
6
7
8
9
SPG SPC SPD
***
*****
common carpcommon carp
No
. of
cyst
s/lo
bu
le
0
10
20
30
40
50
60
70
SPG SPC SPD
******
***
zebrafishzebrafish
% o
f ea
ch s
tag
e in
tes
tis
Wu et al., 2003; Shang et al., 2006
0
50
100
150
200
250
300
Dia
met
er (m
)/L
ob
ule
***
common carpcommon carp
HypoxiaNormoxia
![Page 40: Hypoxia: Problems and Scientific Challenges Hypoxia: Problems and Scientific Challenges Prof. Rudolf Wu School of Biological Sciences The University of.](https://reader035.fdocuments.in/reader035/viewer/2022062511/551b740c550346a10a8b4aea/html5/thumbnails/40.jpg)
0
10
20
30
40
50
60
70
Oo PreV Vit PreO
Ovarian cell stage
% o
f ea
ch s
tag
e in
oo
cyte
***
***
*** ***
zebrafishzebrafish
Shang et al., 2006; Thomas et al., 2007 Landry et al., 2007
% o
f o
oc
yte
s
Atlantic croakerAtlantic croaker
Normoxia Hypoxia
*** p < 0.001
Hypoxia affects OogenesisHypoxia affects Oogenesis