Bathymodiolamides A and B, ceramide derivatives from a deep-sea hydrothermal vent invertebrate mussel, bathymodiolus thermophilus

Article abstract of DOI:10.1021/np100601w

Two ceramide derivatives, bathymodiolamides A (1) and B (2), were isolated from the deep-sea hydrothermal vent invertebrate mussel Bathymodiolus thermophilus. The molecular structures of these compounds were determined using a combination of NMR spectroscopy, mass spectrometry, and chemical degradation. Biological activities were assessed in a ApopScreen cell-based screen for apoptosis induction and potential anticancer activity. To our knowledge, this is the first report of secondary metabolites from the marine hydrothermal vent mussel B. thermophilus.

Full text of DOI:10.1021/np100601w

NOTE
pubs.acs.org/jnp
Bathymodiolamides A and B, Ceramide Derivatives from
a Deep-Sea Hydrothermal Vent Invertebrate Mussel,
Bathymodiolus thermophilus
Eric H. Andrianasolo,† Liti Haramaty,† Kerry L. McPhail,‡ Eileen White,§,^,|| Costantino Vetriani,†
Paul Falkowski,† and Richard Lutz*,†
†Center for Marine Biotechnology, Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New
Brunswick, New Jersey 08901-8521, United States
‡Department of Pharmaceutical Sciences, Oregon State University, Corvallis, Oregon 97331, United States
§Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers, The State University
of New Jersey, Piscataway, New Jersey 08854, United States
^University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854,
United States
The Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, United States
S Supporting Information
b
ABSTRACT:
Two ceramide derivatives, bathymodiolamides A (1) and B (2), were isolated from the deep-sea hydrothermal vent invertebrate
mussel Bathymodiolus thermophilus. The molecular structures of these compounds were determined using a combination of NMR
spectroscopy, mass spectrometry, and chemical degradation. Biological activities were assessed in a ApopScreen cell-based
screen for apoptosis induction and potential anticancer activity. To our knowledge, this is the first report of secondary
metabolites from the marine hydrothermal vent mussel B. thermophilus.
he oceans are the Earth’s largest ecosystem and hold great,
underexplored potential for drug discovery. Within this vast
T
ecosystem, one area remains particularly enigmatic: deep-sea
hydrothermal vents, which are characterized by high concentra-
tions of reduced sulfur compounds.1 Life is supported by the
growth of chemolithoautotrophic bacteria, capable of oxidizing
hydrogen sulfide, hydrogen, and other reduced inorganic com-
pounds to provide energy that is used to fuel carbon dioxide
fixation into macromolecules. The vent mussel Bathymodiolus
thermophilus is characterized by a considerable flexibility in its
sources of nutrition. Symbionts within the gills of this organism
were found to be thiosulfate- and sulfide-oxidizing chemoauto-
trophs.2
Thirty specimens of B. thermophilus were collected using the
deep submergence vehicle DSV Alvin from an active hydrother-
mal vent along the Mid-Atlantic Ridge, northern region, at the
In our ongoing effort to discover and develop new marine
natural product biomedicinals, we have investigated the ability of
the marine hydrothermal vent mussel B. thermophilus to produce
novel secondary metabolites.
Received: August 25, 2010
Published: January 11, 2011
r
Copyright
2011 American Chemical Society and
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dx.doi.org/10.1021/np100601w J. Nat. Prod. 2011, 74, 842–846
American Society of Pharmacognosy
|

Journal of Natural Products
NOTE
Figure 1. Key HMBC and selected COSY correlations for bathymo-
diolamide A (1).
Lucky Strike location with a latitude of 37ꢀ17.630 N, longitude of
32ꢀ16.530 W, and depth of 1733 m.3 Once aboard the research
vessel, the mussels were dissected, and samples of adductor
muscle, gill, and mantle tissues were frozen at -70 ꢀC for
subsequent analyses. One hundred grams wet weight of the
tissues from approximately 20 gills was extracted in MeOH. One
part of the MeOH-soluble extract was dissolved in DMSO and
was tested for apoptosis induction as assessed by the ApopScreen
protocol.4-6 Screening was expected to identify compounds that
possess proapoptotic, and potentially anticancer, activity.
The extract induced apoptosis and therefore was fractionated,
with subsequent purification by analytical reversed-phase HPLC.
Using this strategy, two compounds were isolated. The chemical
structures of these two compounds (1 and 2) were ascertained by
standard spectroscopic techniques, as described below.
Figure 2. Compounds 3-6 resulting from chemical degradation of 1.
The molecular formula of 1 was established as C49H89NO7 on
the basis of HRMALDITOFMS [m/z 804.6712 (M þ H)þ].
The 13C NMR spectrum for 1 clearly indicated resonances for
three ester or amide carbonyl carbons (δC 173.2, 173.4, 173.8),
as well as four oxygen-bearing carbons (δC 59.9, 62.5, 63.7, 66.1)
and one nitrogen-bearing carbon (δC 53.5, δH 4.29). Analysis of
the multiplicity-edited HSQC spectrum for 1 revealed that these
heteroatom-substituted carbons comprise two methylenes (C-
H2-1, δC 63.7, δH 3.65; CH2-5, δC 59.9, δH5a 4.20, δH5b 4.45)
and three methines (CH-2, δC 53.5, δH 4.29; CH-3, δC 62.5, δH
4.01; CH-4, δC 66.1, δH 5.25). The HMBC correlations between
H-2 and the carbonyl at δC 173.2, H-4 and the carbonyl at δC
173.4, and H-5a and H-5b and the carbonyl at δC 173.8 suggested
that 1 has an amide moiety attached to C-2 and two ester
moieties attached to C-4 and C-5. Considering the molecular
formula and all carbon signals for 1, the remaining oxygen-
bearing carbons C-1 and C-3 are substituted with hydroxy
groups, resulting in primary and secondary alcohols at C-1 and
C-3, respectively. The connectivity of C-1 through C-5 of 1 was
established from COSY data as shown in Figure 1, confirming the
presence of the amino alcohol moiety in 1.
The remaining partial structures for 1 could be assigned as
three acyl moieties. Given the six degrees of unsaturation of 1
based on its molecular formula, three double bonds must be
present in one or more of the three acyl moieties. The HMBC
correlations from δH 5.35 to δC 26.5 and from δH 2.81 to
δC 127.5, taken together with the 4H integral of the signal at δH
2.81 in the 1H NMR spectrum of 1, indicated the occurrence of
four bis-allylic protons and two bis-allylic methylene carbons,
suggesting that all three double bonds are located in one branch
of the aliphatic side chain. Since bis-allylic carbon signals for Z
and E isomers are observed at ca. δC 27 and 32, respectively,7,8
the 26.5 ppm shift suggested that all double bonds have a cis
geometry (Z).
Figure 3. Compounds 50 and 60 resulting from chemical degradation
of 2.
routine workup of the reaction, the nonpolar organic extract
was analyzed by GC-MS and ESIMS, and three ion peaks [M þ
H]þ at m/z 215.2010, 265.2166, and 271.2636 were observed,
corresponding to dodecanoic acid methyl ester (4), hexadeca-
trienoic acid methyl ester (5), and hexadecanoic acid methyl
ester (6), respectively (Figure 2).
The regiochemical distribution of these three acyl chains was
established using different ionization mass spectrometry anal-
yses. The amide bond was most readily recognized21 by MAL-
DITOFMS/MS [M þ H]þ at m/z 184.1, corresponding to the
cleavage of the dodecanoyl moiety. ESIMS9 was used to differ-
entiate the acyl attached at C-4 and C-5. Fragmentation by
positive-mode ESIMS generated a more stable fragment ion from
cleavage of the acyl chain attached at C-5 than cleavage of the acyl
chain attached to C-4. In contrast, the negative-mode ESIMS
fragment ion resulting from cleavage of the acyl chain attached at
C-4 is more stable. Successive losses of dodecanoyl and hexade-
catrienoyl moieties were observed in the negative-mode ESIMS
(m/z 584.2 and 367.1, respectively). From these analyses it was
concluded that the dodecanoyl moiety is attached to C-2, while
the hexadecatrienoyl and hexadecanoyl moieties are attached
to C-4 and C-5, respectively. To verify this conclusion, a selective
enzyme reaction was performed. Upon regioselective enzymic
hydrolysis of 1 with lipase enzyme type III in dioxane/H2O (1:1)
at 37 ꢀC for 4 h,10 only hexadecanoic acid was obtained, as evidenced
by ESIMS and comparison with an authentic sample. Thus, it was
concluded that the hexadecanoyl residue is attached to C-5 of 1.
The aqueous phase from the hydrolysis product of 1 yielded
an aminotetraol (3), which was identified as (2S,3S,4R)-2-amino-
1,3,4,5-pentane tetraol. The relative configuration of 3 was
To deduce the identity of the fatty acids, 1 was subjected to a
transesterification reaction in MeOH/NaOMe (2 h). After
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Journal of Natural Products
NOTE
Table 1. NMR Spectroscopic Data for Bathymodiolamide A (1) (500 MHz, CD3OD)
position
1-b
δC, mult.
δH (J in Hz)
HMBCa
1-a
2
63.7, CH2
53.5, CH
62.5, CH
66.1, CH
59.9, CH2
173.2, C
3.65, d (4.5), 3.65, d (4.5)
4.29, dd (4.5, 2)
2, 3
1, 3, 10
3
4.01, dd (2, 6.5)
2, 4
4
5.25, dt (6.5, 3)
3, 5, 100
4, 1000
5-a
10
5-b
100
4.20, dd (12, 3), 4.45, dd (12, 3)
1000
173.4, C
173.8, C
20
30
40
50
60
70
80
90
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000
14000
15000
1600
30.0, CH2
29.9, CH2
29.8, CH2
29.8, CH2
29.8, CH2
29.7, CH2
29.7, CH2
29.5, CH2
29.5, CH2
28.9, CH2
13.2, CH3
30.1, CH2
22.5, CH2
27.5, CH2
24.5, CH2
129.5, CH
127.8, CH
26.5, CH2
127.9, CH
128.1, CH
26.5, CH2
128.0, CH
128.4, CH
25.5, CH2
22.5, CH2
13. 1, CH3
30.2, CH2
29.9, CH2
29.8, CH2
29.8, CH2
29.8, CH2
29.7, CH2
29.7, CH2
29.6, CH2
29.6, CH2
29.5, CH2
29.5, CH2
29.5, CH2
29.4, CH2
28.9, CH3
13.0, CH3
2.31, t (7.5)
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
0.89, t (7.0)
2.35, t (7.2)
1.68, m
1.33, m
2.08, m
5.38, m
5.36, m
2.81, m
5.36, m
5.36, m
2.81, m
5.36, m
5.36, m
2.01, m
1.40, m
0.91, t (7.5)
2.36, t (7.5)
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
0.90, t (7.5)
10, 40
10, 50
20, 60
30, 70
40, 80
50, 90
60, 100
70, 110
80, 120
90, 120
100, 110
100, 400
100, 500
200, 600
300, 700
400, 800
500, 900
600,1000
700, 1100
800, 1200
900, 1300
1000, 1400
1100, 1500
1200, 1600
1300, 1600
1300, 1500
1000, 4000
1000, 5000
2000, 6000
3000, 7000
4000, 8000
5000, 9000
6000, 10000
7000, 11000
8000, 12000
9000, 13000
10000, 14000
11000, 15000
12000, 16000
13000, 16000
14000, 15000
100
110
120
a HMBC correlations, optimized for 8 Hz, are from proton(s) stated to the indicated carbon.
elucidated using the 3JH,H coupling constant analysis from an
NMR database for a given stereocluster.11 Eight stereoisome-
res are possible for aminotetraol (3), depending on the relative
position of H-2 and H-3 (S = syn or A = anti) and H-3 and H-4
(S = syn or A = anti), and the eight isomers are classified as
follows: one pair of SS, one pair AA, one pair of SA, and one
pair of AS. According to the value recorded for 3 of the 3JH,H
coupling constant between H-2 and H-3 (J = 2.5 Hz) and H-3 and
H-4 (J = 7 Hz), H-2 and H-3 are on the same side (S = syn)
and H-3 and H-4 are on the opposite side (A = anti); thus the
remaining probable stereoisomers is the pair of SA: (2S,3S,4R)-2-
amino-1,3,4,5-pentane tetraol and (2R,3R,4S)-2-amino-1,3,4,5pen-
tane tetraol. Theoretically these two isomers should have
opposite optical rotation sign. The positive optical rotation
Thus, it was concluded that the tetradecanoyl residue is attached to
the C-5 position of 2. The hydrolysis of 2 gave similar results
to those observed for 1, with the exception of the presence of
undecadienoic acid methyl ester (50) and tetradecanoic acid
methyl ester (60) (Figure 3). The structure of 2 is similar to 1
with undecadienoyl and tetradecanoyl residues at C-4 and C-5,
respectively. Thus, the structure of 2 was established as shown.
The isolated compounds were evaluated in the apoptosis induc-
tionassay. The results showed that 1 and 2 inhibit the growth
of two cancer cell lines [HeLa (cervical cancer) (IC50 0.4 μM
for 1 and IC50 0.5 μM for 2) and MCF7 (breast cancer) (IC50
0.1 μM for 1 and IC50 0.2 μM for 2)]. The compounds
described herein represent new chemical structures and may
have potential in future drug discovery efforts. Another
interesting observation is that although the deep-sea hydro-
thermal vents are characterized by high concentrations of
reduced sulfur compounds, the presence of sulfur-contain-
ing secondary metabolites from the deep-sea hydrothermal
vent invertebrate mussel Bathymodiolus thermophilu is not
detected.
of 3 ([R]24 þ8 (c 0.05, H2O)) favors the (2S,3S,4R)-2-
D
amino-1,3,4,5-pentane tetraol configuration as that of seen
in L-arabino-phytosphingosine ([R]25 þ5 (c 0.51, pyridine)),22
D
which is also the opposite of that observed in D-arabino-
phytosphingosine ([R]25 -4.3 (c 0.50, pyridine)).22 The
D
identical coupling constants between H-2 and H-3 (J = 3
Hz) and H-3 and H-4 (J = 6 Hz) along with the optical
rotation reported ([R]27 þ9.2 (c 0.05, MeOH)) for the
’ EXPERIMENTAL SECTION
D
sphingosine derivative12-14 and bathymodiolamides A (1)
further suggested a (2S,3S,4R)-configuration of the sphin-
gosine-like moiety in 1. From the above data, the structure
of 1 was established as shown.
General Experimental Procedures. Optical rotations were
measured on a JASCO P 1010 polarimeter. UV and FT-IR spectra were
obtained using Hewlett-Packard 8452A and Nicolet 510 instruments,
respectively. CD spectra were acquired on a JASCO J-720 spectro-
polarimeter. All NMR spectra were recorded on a Bruker Avance
DRX400 spectrometer, a Varian-400 instrument (400 MHz), and a
Varian-500 instrument (500 MHz). Spectra were referenced to residual
solvent resonances at δH/C 3.31/49.15 (CD3OD). ESIMS data were
acquired on a Waters Micromass LCT Classic mass spectrometer and a
Varian 500-MS LC ion trap instrument. MALDITOFMS data were
acquired on an ABI-MDS SCIEX 4800 instrument capable of performing
true MS/MS for peptide analysis. HPLC separations were performed using
The molecular formula of 2 was established as C42H77NO7 on
the basis of HRMALDITOFMS (m/z 730.5594 [M þ Na]þ).
1
The strong similarity of its H NMR spectrum to that of bath-
ymodiolamide A (1) revealed that 1 and 2 share the same general
structural features. Upon regioselective enzymic hydrolysis of 2 with
lipase enzyme type III in dioxane/H2O (1:1) at 37 ꢀC for 4 h,10
only tetradecanoic acid was obtained, as established by
ESIMS analysis and comparison with an authentic sample.
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Journal of Natural Products
NOTE
Table 2. NMR Spectroscopic Data of Bathymodiolamide B (2) (400 MHz, CD3OD)
position
1-b
δC, mult.
δH (J in Hz)
HMBCa
1-a
2
63.7, CH2
53.5, CH
62.5, CH
66.1, CH
59.9, CH2
173.2, C
3.65, d (4.5), 3.65, d (4.5)
2, 3
1, 3, 10
4.29, dd (4.5, 2)
3
4.01, dd (2, 6.5)
2, 4
4
5.25, dt (6.5, 3)
3, 5, 100
4, 1000
5-a
10
5-b
100
4.20, dd (12, 3), 4.45, dd (12, 3)
1000
173.4, C
173.8, C
20
30
40
50
60
70
80
90
200
300
400
500
600
700
800
900
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000
14000
30.0, CH2
29.9, CH2
29.8, CH2
29.8, CH2
29.8, CH2
29.7, CH2
29.7, CH2
29.5, CH2
29.5, CH2
28.9, CH2
13.2, CH3
30.1, CH2
24.5, CH2
127.5, CH
128.1, CH
26.5, CH2
128.0, CH
26.5, CH2
127.9, CH
128.1, CH
26.5, CH2
128.0, CH
30.2, CH2
29.9, CH2
29.8, CH2
29.8, CH2
29.8, CH2
29.7, CH2
29.7, CH2
29.6, CH2
29.6, CH2
29.5, CH2
29.5, CH2
28.4, CH2
13.0, CH2
2.31, t (7.5)
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
0.89, t (7.0)
2.35, t (7.2)
2.08, m
2.36, t (7.5)
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
1.29, brs
0.90, t (7.5)
10, 40
10, 50
20, 60
30, 70
40, 80
50, 90
60, 100
70, 110
80, 120
90, 120
100, 110
100, 400
100, 500
200, 600
300, 700
400, 800
500, 900
600, 1000
700, 1100
800, 1200
900, 1300
1000, 4000
1000, 5000
2000, 6000
3000, 7000
4000, 8000
5000, 9000
6000, 10000
7000, 11000
8000, 12000
9000, 13000
10000, 14000
11000, 14000
12000, 13000
5.38, m
5.36, m
2.81, m
5.36, m
5.36, m
2.01, m
100
110
120
1000
1100
1.40, m
0.91, t (7.5)
a HMBC correlations, optimized for 8 Hz, are from proton(s) stated to the indicated carbon.
Waters 510 HPLC pumps, a Waters 717 plus autosampler, and a Waters
996 photodiode array detector. All solvents were purchased as HPLC grade.
Animal Material. Bathymodiolus thermophilus was collected using
the deep submergence vehicle DSV Alvin from an active hydrothermal
vent along the Mid-Atlantic Ridge (region: north, location: Lucky Strike
(LS), dive number: 3120, date: July 10, 1997, latitude: 37ꢀ17.630 N,
longitude: 32ꢀ16.530 W, depth: 1733 m) and identified by Dr. R. C.
Vrijenhoek (Department of Genetics, Rutgers, The State University of
New Jersey) and Dr. C. Vetriani (IMCS, Rutgers, The State University
of New Jersey). A voucher specimen is available at the Center for Marine
Biotechnology, IMCS, Rutgers, The State University of New Jersey,
New Brunswick, with collection number AD-MUS-LS-7/10/97.
Extraction and Isolation. B. thermophilus tissue (100 g wet mass)
was extracted three times with MeOH to give a polar organic extract
(850 mg). A portion of this extract (20 mg) was tested for induction of
apoptosis and was found to be active. Therefore, the remaining organic
extract was subjected to fractionation using solid-phase extraction on
normal-phase silica to give four fractions, F1 to F4, eluted with hexanes,
hexanes/EtOH, EtOH, and MeOH, in a series of increasingly hydro-
philic solvent systems. The MeOH fraction (F4) had apoptosis induc-
tion activity. This fraction was further chromatographed by analytical RP
HPLC (Phenomenex Luna C18, 250 ꢀ 4.60 mm, isocratic elution 4:1
MeOH/H2O, flow rate 1 mL/min) to yield 11.4 mg of 1 (tR = 11.5 min)
and 8.7 mg of 2 (tR = 9.5 min).
between CHCl3 and H2O. The organic layer was analyzed by GC-MS.
The aqueous layer was also purified and analyzed.
Enzymatic Hydrolysis. Compounds 1 and 2 (2 mg) were dis-
solved separately in 4 mL of dioxane/H2O (1:1) and treated with lipase
enzyme type III (2 mg, 50 unit, from a Pseudomonas species, Sigma-
Aldrich) at 37 ꢀC, with shaking for 4 h. Each reaction mixture was
quenched with 5% AcOH (1 mL), and the product was dried under
reduced pressure. The resulting crude residues were each dissolved in
H2O and extracted with EtOAc, concentrated under reduced pressure,
and analyzed by ESIMS.
Biological Evaluation (Apoptosis Induction). Testing for
induction of apoptosis in the presence of compounds 1 and 2 was
carried out as described in Andrianasolo et al. using the ApoScreen
assay.5,18-20 In this assay, the viability of treated W2 (apoptosis
competent) and D3 (apoptosis defective)15 cells is measured using a
modification of the MTT assay.16 For the current study, viability was
measured at 0 and 48 h, and differential growth was calculated in the
presence and absence of the compounds. Staurosporine (an apoptosis
inducer) was used as a positive control, and DMSO as a negative control.
’ ASSOCIATED CONTENT
S
Supporting Information. NMR and MS data for 1 and 2.
b
This material is available free of charge via the Internet at http://
pubs.acs.org.
Bathymodiolamide A (1):. [R]24 þ10.8 (c 0.08, MeOH); IR
D
νmax (neat) 3350, 3250, 2900, 2850, 1640, 1450, 1050 cm-1; 1H NMR
and 13C NMR, see Table 1; HRMALDITOFMS m/z 804.6712 [M þ
H]þ (calcd for C49H90NO7, 804.6717).
’ AUTHOR INFORMATION
Bathymodiolamide B (2):. [R]24 þ10.9 (c 0.08, MeOH); IR
D
νmax (neat) 3350, 3250, 2900, 2850, 1640, 1450, 1050 cm-1; 1H NMR
and 13C NMR, see Table 2; HRMALDITOFMS m/z 730.5594 [M þ
Na]þ (calcd for C42H77NNaO7, 730.5598).
Corresponding Author
*Tel: (732) 932-8959, ext. 242. Fax: (732) 932-6557. E-mail:
rlutz@imcs.marine.rutgers.edu.
Preparation of Methyl Esters. Compound 1 (7.5 mg) was
dissolved in MeOH (1.5 mL), and NaOMe (2.5 mg) was added; the
reaction mixture was stirred at room temperature for 3 h. The reaction
mixture was quenched with the acidic ion-exchange resin Amberlite
IRC-50 (Rohm and Hass, Hþ form), and the resin was removed by
filtration. The filtrate was dried under reduced pressure and partitioned
’ ACKNOWLEDGMENT
We thank S. Kim for NMR data from NMR facilities in the
Department of Chemistry at Rutgers University. We also thank
H. Zheng for mass spectrometry analysis at the Center for
845
dx.doi.org/10.1021/np100601w |J. Nat. Prod. 2011, 74, 842–846

Journal of Natural Products
NOTE
Advanced Biotechnology and Medicine, Rutgers University. This
research was funded by Rutgers University through an Academic
Excellence award, by NSF grants OCE 03-27373 (R.A.L and
C.V.) and MCB 04-56676 (C.V.), by the New Jersey Agricultural
and Experiment Station (C.V.), and by NIH grant R37 CA53370
(E.W.).
’ REFERENCES
(1) G€artner, A.; Wiese, J.; Imhoff, J. F. Int. J. Syst. Evol. Microbiol.
2008, 58, 34–39.
(2) Nelson, D. C.; Hagen, K. D.; Edwards, D. B. Mar. Biol. 1995, 121,
487–495.
(3) Nees, H. A.; Moore, T. S.; Mullaugh, K. M.; Holyoke, R. R.;
Janzen, C. P.; Ma, S.; Metzer, E.; Waite, T. J.; Y€ucel, M.; Lutz, R. A.;
Shank, T. M.; Vetriani, C.; Nuzzio, D. B.; Luther, G. W., III. J. Shellfish
Res. 2008, 27, 169–175.
(4) Andrianasolo, E. H.; Haramaty, L.; Degenhardt, K.; Mathew, R.;
White, E.; Lutz, R.; Falkowski, P. J. Nat. Prod. 2007, 70, 1551–1557.
(5) Mathew, R.; Degenhart, K.; Haramaty, L.; Karp, C. M.; White, E.
Methods Enzymol. 2008, 453, 53–81.
(6) Karantza-Wadsworth, V.; White, E. In Programmed Cell Death.
Cancer: Principles and Practice of Oncology; DeVita, V. T., Lawrence, T. S.,
Rosenberg, S. A., Eds.; Lippincott, Williams, and Wilkins: Philadelphia,
PA, 2008; pp 93-101.
(7) Ishii, T.; Okino, T.; Mino, Y. J. Nat. Prod. 2006, 69, 1080–1082.
(8) Scribe, P.; Guezennec, J.; Dagaut, J.; Pepe, C.; Saliot, A. Anal.
Chem. 1988, 60, 928–931.
(9) Guella, G.; Frassanito, R.; Mancini, I. Rapid Commun. Mass
Spectrom. 2003, 17, 1982–1994.
(10) Kitagawa, I.; Hayashi, K.; Kobayashi, M. Chem. Pharm. Bull.
1989, 37, 849–851.
(11) Seike, H.; Ghosh, I.; Kishi, Y. Org. Lett. 2006, 8, 3861–3864.
(12) Garg, H. S.; Agrawal, S. J. Nat. Prod. 1995, 58, 442–445.
(13) Natori, T.; Morita, M.; Akimoto, K.; Koezuka, Y. Tetrahedron
1994, 50, 2771–2774.
(14) Mulzer, J.; Brand, C. Tetrahedron 1986, 42, 5961–5964.
(15) Degenhardt, K. S. R.; Chen, G.; Lindsten, T.; Thomson, C.;
White, E. J. Biol. Chem. 2002, 277, 14127–14134.
(16) Denyer, S. P.; Maillard, J.-Y. J. Immunol. Methods 1983, 65, 55–63.
(17) Danial, N.; Korsmeyer, S. Cell 2004, 116, 205–219.
(18) Gelinas, C.; White, E. Genes Dev. 2005, 19, 1263–1268.
(19) Degenhardt, K.; White, E. Clin. Cancer Res. 2006, 12, 5274–
5276.
(20) Fesik, S. W. Nat. Rev. Cancer 2005, 5, 876–885.
(21) Koster, S.; Duursma, M. C.; Boon, J. J.; Heeren, R. M. A.;
Ingemaan, S.; Van Benthem, R. A. T. M.; Kostert, C. G. J. Am. Soc. Mass
Spectrom. 2003, 14, 332–341.
(22) Park, J.-J.; Lee, J. H.; Li, Q.; Diaz, K.; Chang, Y.-T.; Chung, S.-K.
Bioorg. Chem. 2008, 36, 220–228.
846
dx.doi.org/10.1021/np100601w |J. Nat. Prod. 2011, 74, 842–846