With the help of the Merck-AAAS Undergraduate
Science Research Program, Claflin’s Departments of Biology and
Chemistry has established the Merck-AAAS Research Program in
Interdisciplinary Learning (MARPIL). The MARPIL program
institutionalizes a number of novel interdisciplinary instructional
strategies that creates a unique program designed to recruit, inspire,
and retain minority and female students who are trained in the use of
interdisciplinary approaches to biological and chemical problems in
research. This initiative provides a significant and positive
interdisciplinary research experience that blends hands-on research
and conceptual ideas in the fields of chemistry and biology for over
100 minority and female students by incorporating cutting edge
research into the classroom environments of three courses; Organic
Chemistry Lab, Biochemistry Lab, and Environmental Ecology Lab, and
across two departments; Biology & Chemistry. It also provides 18
students with stipend supported summer research experiences to
encourage pursuit of advanced degrees, and teaching valuable critical
thinking skills that merge multiple scientific disciplines to promote
success in future interdisciplinary careers.
1.
Interdisciplinary Research
Project
Background & Significance Cockroach
infestations pose serious health risks especially to children and
adult family members with asthma and other respiratory problems. The
cockroach antigen exacerbates the symptoms of health problems and
cockroaches are regarded as offensive pest because of their residual
odor and potential to cause gastrointestinal illness. To make matters
worse, often pest control methods used in eradicating roaches result
in more serious health problems.
The mosquito is another pest which causes
serious health and economic problems for families in the United States
and other developing countries. For centuries mosquitoes have been
known as vectors for malaria and most recently the West Nile disease
in humans and other animals.
Research into insect pest control has generally
led to three approaches: 1) using chemicals like Pyrethrin
insecticides, organophosphates, organochloro compounds, and carbamates
that attack the insect’s central nervous system, 2) using artificially
synthesized pheromonal attractants to draw insects into traps, and 3)
using synthetic chemicals such as methoprene and fenoxycarb that mimic
the insect’s hormone system to inhibit growth at various stages. This
latest twist in integrated pest management (IPM),
the use of insect growth regulators especially those that
inhibit the completion of metamorphosis from egg to adult are called
“bio-rational approaches”, and offers
an alternative technique for pest control that is relatively less
explored 1. The chemicals used however, are unfortunately
either not highly effective in eliminating these pests, thermally or
photochemically unstable, or have adverse effects on non-target
organisms.
Juvenile
Hormone III (JH III) is one such hormone. JH III interacts with
Juvenile Hormone Esterase (JHE), a protein target that selectively
degrades the hormone, to control development of eggs to adulthood.
1A)
1 B).
1 C)
Figure 1. A) Juvenile Hormone III, B)
Methoprene, C) Fenoxycarb,
The first JH analog to be sold as a bio-rational
insecticide was Methoprene (Fig. 1B). It has been widely used as an
insect growth regulator - specifically as a mosquito larvicide.
Although methoprene is effective in disrupting the progression of the
mosquito larva to adult flying and biting stages of development, it
has been reported as toxic to aquatic organisms,
especially fish. Methoprene is also highly unstable in sunlight,
drastically reducing its effectiveness. Fenoxycarb (Fig. 1C) is also
used in pest control as a JH analog but it has a higher toxicity than
methoprene and is environmentally unsafe in aquatic ecosystems.
Because JH analogs containing aromatic rings are
relatively stable, a large number have been synthesized and their
effectiveness as insecticides tested 2 . Unlike traditional
organic materials, organometallic materials offer the possibility of
designing a large number of aromatic compounds with different metals,
oxidation states, ligands, and molecular symmetry, etc. Ferrocene, the
starting point for the growing discipline of Organometallic Chemistry,
is a thermally and photonically stable “aromatic” 3.
Similarities between traditional organic aromatic compounds and its
aromatic properties are well studied 4 and this moiety may
be a suitable starting point for more stable insecticides. It is non
toxic and biodegradation by-products are also non-toxic, thus making
it a model candidate for use as a bio-rational
insecticide in integrated pest management.
The objective of this project is to synthesize
ferrocene-derived compounds that mimic the mode of action of JH and
test their effectiveness for control of cockroach and mosquito
populations. This research is driven by testing three fundamental
hypotheses for each of the three proposed compounds: 1) a ferrocene
derived analog will be more stable and less photochemicaly active. 2)
synthesized analogs bind to biologically relevant
proteins at biologically relevant concentrations, and 3) analogs will
have an inhibitory effect on the maturation of mosquito and or
cockroach eggs.
Research
Objectives: In this study, a joint initiative between the
Chemistry and Biology departments at Claflin University, MARPIL
Scholars will 1) synthesize the following analogs of JH under the
direction of Dr Raja (Chemistry) (Fig. 2).
Compound I)
Compound II)
Compound III)
Figure 2. Target
Compounds
These analogs are selected for several
reasons: These JH analogs have the ferrocene moiety, which is easy to
introduce, and will likely confer thermal and light stability.
Additionally, the unsubstituted cyclopentadienyl ring in the
ferrocenyl moiety has a distinctive signal in 1H-NMR and 13C-NMR.
These signals will be a useful
Figure 3. JHE/Methoprene (2FJO)
marker in planned protein studies using NMR
spectroscopy. 2) As analogs are made, MARPIL Scholars will move to Dr
Panasik’s lab (Biology) to make direct measurements of the analog’s
interaction with its target proteins – JHE; establishing precise
association constants. Students will clone, express, and purify JHE,
learning vital concepts of molecular biology in the process. 3) Moving
to research in Dr Iyer’s lab (Chemistry), the cross over between
chemistry and biology will be exemplified as students co-crystallize
analogs with purified protein, explore crystal growth conditions, and
submit the crystals for x-ray crystallographic study. In the event
that crystallization attempts fail, students will use molecular
modeling tools in Panasik’s lab to model interactions. Crystal
structures currently exist for JHE and JHE-methoprene complex (2FJO)
(Fig 3). These are suitable templates for homology modeling. 4)
Concurrently, in the lab of Mrs. Anoruo (Biology), students will
directly measure the activity of analogs on eggs of cockroaches and
mosquitoes, perform comparative analysis analog efficacy in different
application methods, and determine the effective dose to achieve 90%
or higher rates of success in the inhibition of successful completion
of the metamorphic process for both the mosquito and cockroach. In
this way, students will learn to measure biological repercussions of
chemical compounds by experimenting with dosage and delivery and
monitoring morphological effects on the biology of the target
organisms.
2.
Joint Promotion of the Related Nature of Biology and Chemistry
These projects are implemented in a novel
marriage between a problems-based course curricula approach for all
students taking 3 required courses, coupled with full time hands-on
summer research for six select students from these classes. As a
primary layer to this interdisciplinary approach, we implement the
proposed project as part of the laboratory component of 3 required and
successive courses: Organic Chemistry II, Biochemistry I, and Ecology.
Organic II is taken in the final semester of sophomore year,
biochemistry lab I is taken the first semester of junior year, and
Ecology may be taken as a restricted elective (required for
participants in MARPIL summer program) in the second semester of their
Junior year. In organic chemistry lab II, students in the class will
be divided into cohorts of 4, with cohorts working on synthesis of one
of the 3 novel target compounds listed above. Students will learn
organic synthesis techniques, IR and NMR characterization under the
guidance of Dr Raja, Professor of the course and participant in this
grant. The top 6 students of the class (2 from each of the three
synthesis projects) will be selected as “MARPIL Scholars” to
participate in stipend-supported research for the summer of their
sophomore year. During this summer, students continue characterizing
the compounds and compare them to methoprene. Students will
participate in weekly joint meetings between the Raja, Panasik, Anoruo,
and Iyer labs to discuss behaviors of these compounds, measured
characteristics, and the physiological pathways involved. Students
will present their results to the group and future classes.
In the following fall semester, cohorts from
Organic II Lab will be maintained in Biochem I Lab. In this
problems-based course, under mentorship of Dr. Panasik (Biology), they
will study the interactions of the compounds they synthesized with the
biological targets. After cloning, expressing, and purifying JHE, the
analogs target protein, they will measure the association constants of
the analog and measure its effect on the kinetics of esterase
activity. MARPIL Scholars will act as peer mentors to their cohort
within this class.
Following Biochem I lab, in spring semester of
their junior year, students will again participate in hands-on mentor
driven research. Under the direction of Dr Iyer (Chemistry), students
will attempt to co-crystallize analogs with JHE for x-ray
crystallographic study. In conjunction with Dr Panasik they will use
molecular modeling techniques to study the structure-function
relationships of the protein-hormone complex. Weekly inter-lab group
meetings will be maintained.
Concurrent with this research, MARPIL Scholars,
will be taking Ecology I lab with Mrs. Florence Anoruo (Biology).
Students in this problems-based lab will directly analyze the effects
of their synthesized compounds on eggs of target pests. Afterwards, at
least 2 MARPIL Scholars will continue in stipend-supported summer
research to complete their project -supported by funds identified or
allocated by the departments as part of CU matching (see Institutional
Support). As a final capstone to this project, all MARPIL Scholars
will include this research as part of their senior thesis as well as
submit their findings to one or more peer reviewed scientific
journals. MARPIL Scholars will receive first authorship for articles
related to their synthesized compound while other student researchers
involved in research on that compound will be included as additional
authors.
The greater impact of this research however,
beyond creation and characterization of three novel compounds which
are potentially useful for pest management is that the impact of the
Merck-AAAS interdisciplinary approach will be extended to the over 100
minority biology and chemistry students (65% of whom are first
generation college students) who will be taking these modified
courses. Six will be selected each year to participate in the MARPIL
Scholar summer research program and these students will serve as peer
mentors, and give a presentation on their research to successive
classes as classes begin their synthesis projects. Bridging the gap
between chemistry and biology, students will be exposed to the broad
range of scientific techniques from chemical synthesis to the effect
on biological phenotype. Over the course of 3 years, 18 students will
have participated in full time laboratory research and presented their
findings to the School of Natural Sciences and Mathematics and
regional and/or national science meetings.
3.
Incorporation into Existing Research Projects:
Currently, the Biology and Chemistry Departments provide 38 fully
supported research internships through Howard Hughes Medical Institute
(HHMI), and various National Institutes of Health and National Science
Foundation grants. Six MARPIL Scholars will be added to that number
each year and we will find support through one of these programs or
through departmental support, for at least two of the successful
MARPIL Scholars from the previous years. As there are currently 210
students in Biology & Chemistry combined, the total number of summer
research students would be roughly 21%. Implemented as part of these
three courses, MARPIL will impact ALL biology and chemistry students
enrolled in SNSM, provide a novel, competency-based means of
recruitment (those who scored well in the initial hands-on lab
course), and provide a forum to showcase future MARPIL successes.
Complimenting existing research
projects, students will participate in regular lab group meetings with
each of their mentors, leading journal clubs related to their research
and listening to lab-mate presentations. Students will interact with
other students in all 4 of the respective fields of their mentors and
learn the commensurate scientific methodology and techniques, building
a strong foundation of interdisciplinary research, communication, and
leadership skills.
4.
Facilities: There are 9 undergraduate laboratories and 7
faculty research areas that are fully funded by extramural support and
have over 12,600 sq feet of research space. There are 9 Optiplex 650
workstations each in chemistry & biology that are available for
students, 1 computer instruction room, three full molecular biology
labs in addition to the teaching labs that are complete with gel
apparatus, reagents, enzymes, etc, an organic synthesis lab, and 1
green house. Equipment includes: 300 MHz NMR; FTIR; Atomic
Absorption, GC Mass, Fluorescence and 2 Temperature controlled UV-Vis
Spectrometers, HPLC; Capillary Electrophoresis System. Protein
electrophoresis equipment ; DNA fluorimeter; hybridization ovens,
French pressure cell, sonicator, Beckman JA centrifuge, 2x gel
densitometers, high, low, and mesophilic temperature incubators
(shaking and static); -70, -30, -4 freezers, 8 refrigerators, 2
computational computers with 8G RAM 2x2.3 GHz processors, 1 TB
combined storage, 3 lab computers in labs involved in MARPIL, 10x 3D
shutter glasses, 3D projector for molecular imaging and lectures, and
local lab intranet.
5.
Institutional Support & Commitment to Undergraduate Research
In evidence of a. strong commitment to fostering an
interdisciplinary scientific approach between Chemistry and Biology
the Biology department has recently changed its curriculum so that
Biology majors earn a minor in chemistry. Biology students are
encouraged to pursue undergraduate research projects in chemistry and
those in chemistry are likewise encouraged. The Institution will
support MARPIL by providing $4000 in related supplies for Organic Lab
II, Biochem Lab I, and Ecology and by including the conceptual
training needed for their research in required core curricula. The
university will also provide housing during the summer sessions. The
biology department will sponsor all poster production for regional and
national meetings. At least two MARPIL Scholars who have completed
summer research supported by MERCK-AAAS will be selected to continue
their research in an added summer of stipend supported research via
extramural or departmental funds.
6.
Ancillary Programs: In any interdisciplinary approach to
science, it is important to reinforce the development of communication
skills that bridge gaps between disparate communities. Equally
important is the establishment of “Learning Communities”, wherein
students can regularly discuss related research and concepts learned
in a forum that promotes interaction, questioning, and brainstorming.
Commensurately, MARPIL Scholars will give presentations on their
research in both Chemistry and Biology Seminars, giving a useful forum
for presentations of interdisciplinary projects. Participating
students will meet with mentors to adapt presentations so they may
remain technically specific yet understandable to both communities.
Mentors will discuss how to draw associations and connections between
concepts central yet traditionally exclusive to the two fields.
7.
Allocation of Funds. Each year, six students will
receive $3,000 per summer session as a summer stipend. $2000 will be
used for supplies.
References.
1. E. Garfield, Current Contents
1990, 46, 413-421.
2 L.I. Gilbert, A. Granger, and R. M. Roe
Insect Biochemistry. Molecular Biology 2000, 30, 617-644.
3.J. Halpern, Pure Applied Chemistry.
2001, 73, 209.
4.R. H. Crabtree “ The organometallic chemistry
of the transition metals” John Wiley 2005.
