Transcriptome Profiling and In Silico Analysis of the Antimicrobial Peptides of the Grasshopper Oxya chinensis sinuosa

Abstract

Antimicrobial peptides/proteins (AMPs) are present in all types of organisms, from microbes and plants to vertebrates and invertebrates such as insects. The grasshopper Oxya chinensis sinuosa is an insect species that is widely consumed around the world for its broad medicinal value. However, the lack of available genetic information for this species is an obstacle to understanding the full potential of its AMPs. Analysis of the O. chinensis sinuosa transcriptome and expression profile is essential for extending the available genetic information resources. In this study, we determined the whole body transcriptome of O. chinensis sinuosa and analyzed the potential AMPs induced by bacterial immunization. A high-throughput RNA-seq approach generated 94,348 contigs and 66,555 unigenes. Of these unigenes, 36,032 (54.14%) matched known proteins in the NCBI database in a BLAST search. Functional analysis demonstrated that 38,219 unigenes were clustered into 5,499 Gene Ontology (GO) terms. In addition, 26 cDNAs encoding novel AMPs were identified by an in silico approach using public databases. Our transcriptome data set and AMP profile greatly improves our understanding of O. chinensis sinuosa genetics and provides a huge number of gene sequences for further study, including genes of known importance and genes of unknown function.

Full text

November 2016
⎪
Vol. 26
⎪
No. 11
J. Microbiol. Biotechnol. (2016), 26(11), 1863–1870
http://dx.doi.org/10.4014/jmb.1608.08029
Research Article
jmb
Review
Transcriptome Profiling and In Silico Analysis of the Antimicrobial
Peptides of the Grasshopper Oxya chinensis sinuosa
In-Woo Kim
1†
, Kesavan Markkandan
2†
, Joon Ha Lee
1
, Sathiyamoorthy Subramaniyam
2
, Seungil Yoo
2
,
Junhyung Park
2
*, and Jae Sam Hwang
1
*
Department of Agricultural Biology, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365,
Republic of Korea
Theragen ETEX Bio Institute, Theragen Etex Inc., Suwon 16229, Republic of Korea
Introduction
Oxya chinensis sinuosa
is a grasshopper species belonging
to the phylum Arthropoda (Order: Orthoptera; Family:
Acrididae; subfamily: Oxyinae) that is edible and widely
consumed. There are approximately 1,900 edible insects,
and among these, insects belonging to the Orthoptera are
the fourth most commonly consumed at its mature stage [3,
19]. Orthopteran insects are also commonly used for
entomotherapy [5], and are used to treat various human
ailments, including enuresis in women, scorpion stings,
anemia, violent headaches, foot inflammation, fertility,
hypertension, asthma, stroke, and skin diseases [7]. These
conditions are ameliorated by the combination of
biochemicals, including proteins, minerals, and fatty acids,
that are present in insect hemocytes and fat body mass.
Antimicrobial peptides (AMPs) are small peptides/
proteins (~100 aa) that are secreted/triggered by the host
innate immune system in response to external microbial
infection. AMPs are important components of the host
defense system in all invertebrates. In addition, AMPs are
considered as an alternative to conventional antibiotics
[18]. Recently, AMPs have been predicted in insect
transcriptomes, and these transcriptome profiles revealed
that defensins, cecropins, and attacins are widely distributed
in insects [15]. In the genomic era, most of the bases present
Received: August 11, 2016
Revised: August 19, 2016
Accepted: August 30, 2016
First published online
September 2, 2016
*
Corresponding authors
J.S.H.
Phone: +82-63-238-2974;
Fax: +82-63-238-3833;
E-mail: hwangjs@korea.kr
J.P.
Phone: +82-31-888-9318;
Fax: +82-31-888-9335;
E-mail: junhyung.park@
theragenetex.com
These authors contributed
equally to this work.
upplementary data for this
paper are available on-line only at
http:
//
jmb.or.kr.
pISSN 1017-7825, eISSN 1738-8872
Copyright
©
2016 by
The Korean Society for Microbiology
and Biotechnology
Antimicrobial peptides/proteins (AMPs) are present in all types of organisms, from microbes
and plants to vertebrates and invertebrates such as insects. The grasshopper
Oxya chinensis
sinuosa
is an insect species that is widely consumed around the world for its broad medicinal
value. However, the lack of available genetic information for this species is an obstacle to
understanding the full potential of its AMPs. Analysis of the
O. chinensis sinuosa
transcriptome
and expression profile is essential for extending the available genetic information resources. In
this study, we determined the whole-body transcriptome of
O. chinensis sinuosa
and analyzed
the potential AMPs induced by bacterial immunization. A high-throughput RNA-Seq
approach generated 94,348 contigs and 66,555 unigenes. Of these unigenes, 36,032 (54.14%)
matched known proteins in the NCBI database in a BLAST search. Functional analysis
demonstrated that 38,219 unigenes were clustered into 5,499 gene ontology terms. In addition,
26 cDNAs encoding novel AMPs were identified by an in silico approach using public
databases. Our transcriptome dataset and AMP profile greatly improve our understanding of
O. chinensis sinuosa
genetics and provide a huge number of gene sequences for further study,
including genes of known importance and genes of unknown function.
Keywords:
Grasshopper,
Oxya chinensis
, transcriptome, antimicrobial peptides, insect-derived
AMP
S
S

1864 Kim et al.
J. Microbiol. Biotechnol.
in cells are sequenced by next-generation sequencing (NGS)
technologies and annotated using bioinformatics methods
[10]. To uncover the hidden benefits of insects in ecology
and human health, the insect research community has
collectively undertaken two molecular meta-data projects,
the 1K Insect Transcriptome Evolution (1KITE) and 5,000
Insect Genome Project (i5k) [17]. The largest sequenced
insect genome (~6 Gb) belongs to an Orthopteran (
Locusta
migratoria
) [23]. Currently, only a few
Oxya
molecular
studies have been published, on heavy metal stresses and
nutrient supplements. Specifically,
Oxya hyla hyla
and
Oxya chinensis
have been studied as potential heavy metal
bioindicators in industrial agricultural fields [1, 3, 27], and
O. fuscovittata
and
O. hyla hyla
have been
studied as
nutrient supplements for fish [9] and poultry birds [19].
Since
O. chinensis sinuosa
has long been used as a food
source for the South Korean population and it possesses
antioxidant and antimicrobial properties [9], we sought to
examine its transcriptome.
Therefore, in the present study,
we set out to obtain high-throughput data of the
O. chinensis
sinuosa
transcriptome using Illumina-based NGS. In addition,
we obtained the first transcriptome data for a member of
the Oxyinae subfamily, and predicted the AMPs as
preliminary data to support future molecular studies.
Materials and Methods
Insects and Treatment
Adult
O. chinensis sinuosa
were obtained from Jeonnam
Agricultural Research & Extension Services, South Korea. For
immunization, each grasshopper was injected with log phase
Escherichia coli
(4 × 10 colony forming units) suspended in 10
μ
l of
autoclaved 10 mM sodium phosphate buffer (pH 7.4). Non-
immunized and immunized grasshoppers were reared at 25°C ±
1°C for 18 h before total RNA isolation.
E. coli
Strain and Growth Conditions
E. coli
KACC 13821 (ATCC 11775) was purchased from the
Korean Agricultural Culture Collection (KACC). Bacteria were
cultivated overnight in tryptic soy broth (TSB; Difco, USA) in a
shaking incubator (200 rpm, 37°C) until the stationary phase.
Then, the bacteria were cultivated in fresh TSB medium under the
same conditions until log phase (for 3 h). Bacteria were stored in
15% glycerol at −70°C until use.
Library Preparation and Sequencing
Total RNA was extracted from each sample with the RNeasy
Lipid Tissue Kit (Qiagen, Germany) according to the manufacturer’s
instructions after treatment with RNase-free DNase I (Qiagen) to
eliminate genomic DNA. The concentration and integrity of the
RNA were assessed with a Thermo Scientific NanoDrop 8000
Spectrophotometer and Agilent 2100 Bioanalyzer, respectively
(Agilent Technologies, USA). RNA with an OD
≥
1.8 and an
RNA integrity number
≥
7.0 was used in subsequent experiments.
Equal amounts of high-quality RNA from tissues were then
pooled for cDNA synthesis and sequencing. The cDNA library
was prepared with ~2.5
μ
g of total RNA according to the Illumina
TrueSeq RNA Sample Preparation Kit (Illumina) protocol. The
library was then amplified, and the final library yielded ~400 ng
of cDNA, with an average fragment size of ~300 bp. The resulting
cDNA libraries (for all four samples) were then paired-end
sequenced (2 × 150 bp) with NextSeq (Illumina).
Preprocessing, De Novo Assembly, and Annotations
Paired-end sequence files from four samples (Fastq: R1, R2)
were obtained and subjected to processing using Trimmomatic-
0.32, with the following parameter settings: leading, 5; trailing, 5;
sliding window, 4:15; and minlen, 30. Processed sequences were
checked for bacterial contamination using an in-house bacterial
database that was constructed from NCBI GenBank. Preprocessed
clean reads were mapped to the bacterial database using Bowtie2
with default parameters, and the mapped reads and their
respective pairs were removed. From this point on, these
sequences are called preprocessed. Total preprocessed sequences
from NextSeq were pooled and assembled with Trinity assembler
ver. 2.0.6 [11] using default values. To remove redundant
sequences, CD-HIT-EST [13] was used, with a 95% sequence
similarity cutoff. Finally, transcripts greater than 500 bp were
selected for inclusion in the reference transcriptome. The
reference transcriptomes were subjected to functional annotation
using BLASTX mapping (e-value cutoff 1e ) against the UniProt
KB (Metazoa) database, and the Gene Ontology (GO) terms and
Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway
maps were determined using Blast2GO [6]. GO annotations were
classified using the WEGO Web server [25].
Identification of Differentially Expressed genes
Differentially expressed genes (DEGs) were measured by
counting tags in immunized samples and comparing the number
with that in non-immunized
O. chinensis sinuosa
samples and were
normalized using the RNA Sequence Expected Maximization
method [16]. Reads from all samples were mapped to the
reference transcriptome, and differential expression was assessed
using Trinity utility scripts (align_and_estimate_abundance.pl
and abundance_estimates_to_matrix.pl) as instructed (http:
//
trinityrnaseq.github.io/). From the edgeR statistics files,
regulated transcripts across libraries were filtered with default
parameters (
i.e
., 1
≤
log (FC), FDR < 0.01) using Python scripts. To
determine the differential expression pattern from the GenBank
datasets, the same procedures were followed.
Antimicrobial Peptide Prediction and Classification
The deduced amino acid sequences were subjected to AMP
prediction using a modified bioinformatics strategy. Peptide

Antimicrobial Peptides in the Grasshopper Oxya chinensis sinuosa 1865
November 2016
⎪
Vol. 26
⎪
No. 11
characteristics such as (i) molecular propensity (physicochemical
properties) (ii) aggregation propensity (in vitro and in vivo), and
(iii) AMP prediction were assessed by using a predefined
bioinformatics strategy with the given parameters [24]. In
addition, the allergenic propensity of the peptides was predicted
using Allerdictor [8, 22]. Finally, the AMPs were mapped with the
CAMP database [22] and classified as novel or known. To classify
the AMPs as novel, sequences were matched to the CAMP
database with two programs, PatMatch (no mismatch) for
sequences
≤
20 amino acids [19] and BLASTP (1E-05) for sequences
≥
20 amino acids. The BLAST results were filtered using a
similarity score
≥
90. Similar sequences, using the given cutoff,
were considered as known AMPs, and the others were considered
novel AMPs.
Data Deposition
The raw reads from
O. chinensis sinuosa
were submitted to the
NCBI Sequence Read Archive under Accession No. SRP080832.
Results and Discussion
Transcriptome Sequencing and Assembly
The de novo transcriptome of
O. chinensis sinuosa
was
processed as depicted in Fig. 1. To obtain a more
comprehensive view of the transcriptome, pooled cDNA
samples from the non-immunized control and
E. coli
-
immunized
O. chinensis sinuosa
were isolated. Illumina
sequencing produced an average of 40,809,315 and
40,232,081 clean reads, representing 5.52 Gb and 5.41 Gb of
the non-immunized control and immunized samples,
respectively (Table 1). The quality of the transcriptome
sequence was high, with a Q percentage (percentage of
sequences with a sequencing error rate lower than 1%) of
85.74% and 45.16% G+C. These short reads were assembled
into 94,348 contigs with a mean length of 1,439 bp. We
obtained 66,555 unigenes, with a mean size of 1,286 bp
(range, 500–26,614 bp), implying that the pipeline used to
assemble the
O. chinensis sinuosa
transcriptome libraries
Fig. 1.
Workflow of the transcriptome assembly and analysis
of
Oxya chinensis sinuosa
high-throughput sequencing data.
Tab le 1 .
Sequencing, assembly, and annotation statistics.
A. Sequencing
Control (non-immunized) Immunized
Total sequenced bases 13,720,373,521 100% 13,550,796,905 100%
Total preprocessed bases 11,053,358,720 81% 10,834,378,027 80%
B. Assembly
Contigs Bases
Trinity 94,383 100% 135,864,252 100%
CD-HIT-EST 64,047 67.8% 82,380,545 60.6%
C. Annotation
No. of Contigs %
No. of hits 30,523 45.6%
BLAST 36,032 54.1%
Gene Ontology 18,991 29.6%
KEGG 3,115 4.8%

1866 Kim et al.
J. Microbiol. Biotechnol.
was satisfactory (Fig. 1). Of these unigenes, 28,049 (42.14%)
were longer than 1,000 bp. BLAST searching matched
36,032 unigenes (54.14%) to known genes, suggesting that
the assembly quality was high (Table 1). The remaining
unigenes could not be matched to any known gene, as
there is currently no genome information available for
O. chinensis sinuosa
. Recently, the transcriptome profiles of
some insect species in the Acrididae family, including
Schistocerca gregaria
,
Locusta migratoria
,
and
Epacromius
coerulipes
, were investigated using cDNA libraries [2, 4, 14].
Fig. 2.
Annotation of the
Oxya chinensis sinuosa
transcriptome.
(
A
) Histogram of the GO classifications. The
O. chinensis sinuosa
transcriptome was annotated in three ontology categories: “Biological Processes,”
“Cellular Component,” and “Molecular Function.” (
B
) Species distribution of the BLASTX matches to transcriptome unigenes against the nr
protein database (cutoff value E < 10 ) and the proportion of matches in each species.

Antimicrobial Peptides in the Grasshopper Oxya chinensis sinuosa 1867
November 2016
⎪
Vol. 26
⎪
No. 11
In addition, the antennal transcriptome of the odorant-
binding proteins in the grasshopper
Oedaleus asiaticus
has
also been studied [26]. However, there has been no
published research on bacteria-immunized grasshoppers.
The current transcriptome sequencing of
O. chinensis sinuosa
provided significant amounts of information (66,555 unigenes)
compared with that available for other grasshoppers, revealing
more detailed genetic and gene expression data that were
produced using whole-body transcriptome sequencing.
Annotation of Predicted Proteins
To determine the putative annotations of the reference
transcripts, distinct sequences were first searched by
BLASTX against the GenBank non-redundant protein
database, with an E-value cutoff of 10 using Blast2GO, as
described in the Materials and Methods section. A total of
36,032 distinct sequences (54.14% of the unigenes) were
matched to known genes that encode functional proteins.
The percentage of unigenes matching known proteins was
much higher than those reported in the whole-body
transcriptomes of
S. gregaria
and
L. migratoria
[2, 4]. Of the
total unigenes, almost half (30,523) shared no significant
similarity to known genes; therefore, these may be novel or
fast-evolving sequences. Studying these transcripts will
provide information about insects in the family Acrididae.
In addition, our results will also be useful for future
studies, such as the cloning and characterization of
O. chinensis sinuosa
genes. In the functional annotation,
5,499 GO terms were assigned, which were subsequently
categorized into three level 2 category observations;
biological processes (13,736), cellular component (8,834),
and molecular function (15,649) (Fig. 2A). Within the
biological processes category, genes encoding metabolic
processes (16.8%) and cellular processes (16.7%) were the
most enriched. Proteins related to cells (14.4%) and cell
part (14.3%) were enriched in the cellular component
category. With regard to the category of molecular
function, catalytic (27.0%) and binding (26.6%) were the
most highly represented categories. It is not very surprising
that numerous sequences were classified into every GO
category. These are more general GO terms that comprise
the basic processes required to maintain a living organism.
The top BLASTX hit showed that
O. chinensis sinuosa
is
highly homologous to
Zootermopsis nevadensis
(44%),
followed by
Acyrthosiphon pisum
(3%).
O. chinensis sinuosa
shared only 2% homology with
Locusta migratoria
(Fig. 2B).
Our data are the first ever transcriptome profile of an
organism belonging to the genus
Oxya
,
and the above
results suggest more representative collections of
O. chinensis
sinuosa
genes in this study.
Analysis of Differentially Expressed Genes
Pairwise comparisons of the non-immunized control and
immunized
O. chinensis sinuosa
for differential expression
analysis revealed a total of 2,887 DEGs (Table S1). The MA
plot showed significant DEGs (blue) against all nonsignificant
DEGs (red) (Fig. 3). Among the identified DEGs, 1,800 were
expressed at significantly higher levels in the control,
whereas 1,087 genes were expressed at significantly higher
levels in the immunized sample. In addition, 2,117 genes
showed more than a 10-fold difference between the non-
immunized control and immunized samples (Fig. 3). Of the
DEGs, 1,053 could not be annotated using any database,
and 419 of these were more highly expressed in immunized
Fig. 3.
MA plot of differentially expressed genes in the transcriptome of non-immunized control and
E. coli
-immunized
O. chinensis sinuosa
.
Data are the individual gene responses plotted as log fold-change versus base mean fold-change >2 (
p
< 0.05), with negative changes representing
downregulated genes and positive changes representing upregulated genes.

1868 Kim et al.
J. Microbiol. Biotechnol.
samples. Of the 2,887 DEGs, 512 were annotated as
homologous genes in
Zootermopsis nevadensis
, a dampwood
termite that is closely related to
O. chinensis sinuosa
. The
number of genes with higher expression levels in immunized
O. chinensis sinuosa
was lower than that in the control, which
clearly showed that the bacterial infection was significant.
In Silico Identification of AMPs
Insects produce a greater number of AMPs than any
other taxonomic group, and the number of individual
AMPs produced by each insect species varies substantially
[18, 21]. A vast number of studies have been performed
that have identified more than 100 insect-specific AMPs by
high-throughput, forward genetics approaches and various
screening procedures [12]. Our comprehensive transcriptome
dataset from non-immunized control and bacteria-immunized
O. chinensis sinuosa
was screened extensively for cDNAs
encoding AMPs using public databases (Table 2). We
identified 26 novel AMPs (non-allergen) belonging to
diverse families and functional classes (Table S2). Among
these, nine are involved in various biological functions,
whereas the remaining 17 have unknown/uncharacterized
functions. Furthermore, our DEG results revealed that
most of the AMPs were differentially expressed, and this
was visualized by preparing a heat map to compare the
normalized mapped read (RPKM) values of each AMP
between the non-immunized control and immunized
samples (Fig. 4).
High-throughput analyses, such as RNA-Seq, have led to
the discovery of not only many immune-related genes but
also the corresponding networks and pathways involved in
pathogen recognition, signal transduction, and effector
functions, including AMPs [20]. Previous reports have
identified several potential AMPs in insects of various
orders [18]. Recently, the transcriptome of the ladybird
beetle,
Harmonia axyridis
, was analyzed for AMPs induced
against
E. coli
,
Micrococcus luteus
, and
Saccharomyces cerevisiae
[21]. Several novel AMPs in
Periplaneta americana
were
identified in an
E. coli
-immunized de novo
transcriptome
and were validated in vitro. Indeed, most of these AMPs
are involved in defense and protein binding [15].
In conclusion, transcriptome sequencing and annotation
can be used to provide remarkable information for analyzing
the molecular basis of the economically important traits of
an organism. Here, we described the first comprehensive
investigation of the
O. chinensis sinuosa
transcriptome. In
this study, we characterized the transcriptome of
E. coli
-
immunized
O. chinensis sinuosa
and identified a significant
number of AMPs through an in silico approach. The
transcriptome data assembled in this study will be a valuable
resource for future studies, including gene expression and
annotation studies of the
O. chinensis sinuosa
genome.
Tab le 2 .
In silico functional characterization of identified AMPs.
Filter Propensity Method Cutoff No. of total peptide Seq
Step 1 Molecular Pepstats Total peptides (
≤
100) 58,696
Charge >0(+) 55,073
8
≤
pI
≤
12 41,207
Aggregation TANGO
(in vivo)
AGG
≤
500 42,866
0
≤
HELIX
≤
25 41,612
25
≤
BETA
≤
100 18,134
Homologs BLAST Known (similarity >90%) 1,627
Novel Novel (no BLAST score) 57,069
Allergen Allerdictor Non-allergen 58,261
Filter 1 total (common) 9,015
Step 2 Aggregation Aggrescan (in vitro) -40
≤
Na4vSS
≤
60 8,065
CAMP SVM AMP 1,526
RF AMP 1,908
ANN AMP 2,934
DA AMP 2,024
(3 out of 4)
≥
3 1,496
Final peptides (Filter 2 common) 1,346

Antimicrobial Peptides in the Grasshopper Oxya chinensis sinuosa 1869
November 2016
⎪
Vol. 26
⎪
No. 11
Promising insect-derived AMPs are currently being
employed in various medicinal applications. Therefore, our
future work will focus on producing
Oxya
-derived AMPs
in the quantities required for topical therapeutic applications.
Acknowledgments
This research was supported by a grant (PJ01099301) from
the Agenda Program, Rural Development Administration.
References
1. Azam I, Afsheen S, Zia A, Javed M, Saeed R, Sarwar MK,
Munir B. 2015. Evaluating insects as bioindicators of heavy
metal contamination and accumulation near industrial area
of Gujrat, Pakistan.
Biomed
.
Res
.
Int
.
2015:
942751.
2. Badisco L, Huybrechts J, Simonet G, Verlinden H, Marchal
E, Huybrechts R,
et al.
2011. Transcriptome analysis of the
desert locust central nervous system: production and
annotation of a
Schistocerca gregaria
EST database.
PLoS One
6:
e17274.
3. Badman J, Harrison JF, McGarry MP. 2007. Grasshoppers in
research and education: methods for maintenance and
production.
Lab Anim
.
(NY)
36:
27.
4. Chen S, Yang P, Jiang F, Wei Y, Ma Z, Kang L. 2010. De
novo analysis of transcriptome dynamics in the migratory
locust during the development of phase traits.
PLoS One
5:
e15633.
5. Cherniack EP. 2010. Bugs as drugs, Part 1: Insects: the “new”
alternative medicine for the 21st century.
Altern
.
Med
.
Rev
.
15:
124-135.
6. Conesa A, Götz S, García-Gómez JM, Terol J, Talón M,
Robles M. 2005. Blast2GO: a universal tool for annotation,
visualization and analysis in functional genomics research.
Bioinformatics
21:
3674-3676.
7. Costa-Neto EM. 2005. Entomotherapy, or the medicinal use
of insects.
J
.
Ethnobiol
.
25:
93-114.
8. Dang HX, Lawrence CB. 2014. Allerdictor: fast allergen
prediction using text classification techniques.
Bioinformatics
30:
1120-1128.
9. Ganguly A, Chakravorty R, Sarkar A, Mandal DK, Haldar P,
Ramos-Elorduy J, Moreno JMP. 2014. A preliminary study
on
Oxya fuscovittata
(Marschall) as an alternative nutrient
supplement in the diets of
Poecillia sphenops
(Valenciennes).
PLoS One
9:
e111848.
10. Goodwin S, McPherson JD, McCombie WR. 2016. Coming of
age: ten years of next-generation sequencing technologies.
Nat
.
Rev
.
Genet
.
17:
333-351.
11. Haas BJ, Papanicolaou A, Yassour M, Grabherr M, Blood
PD, Bowden J,
et al.
2013. De novo transcript sequence
reconstruction from RNA-Seq using the Trinity platform for
reference generation and analysis.
Nat
.
Protoc
.
8:
1494-1512.
Fig. 4.
Heat map showing relative expression levels of
differentially expressed
O. chinensis sinuosa
antimicrobial peptides.
The data are log -transformed RPKM values (green, lower-expressed
genes; red, highly expressed genes).

1870 Kim et al.
J. Microbiol. Biotechnol.
12. Hadley EB, Hancock RE. 2010. Strategies for the discovery
and advancement of novel cationic antimicrobial peptides.
Curr
.
Top
.
Med
.
Chem
.
10:
1872-1881.
13. Huang Y, Niu B, Gao Y, Fu L, Li W. 2010. CD-HIT Suite: a
Web server for clustering and comparing biological sequences.
Bioinformatics
26:
680-682.
14. Jin Y, Cong B, Wang L, Gao Y, Zhang H, Dong H, Lin Z.
2016. Differential gene expression analysis of the
Epacromius
coerulipes
(Orthoptera: Acrididae) transcriptome.
J
.
Insect Sci
.
16:
42.
15. Kim I-W, Lee JH, Subramaniyam S, Yun E-Y, Kim I, Park J,
Hwang JS. 2016. De novo transcriptome analysis and detection
of antimicrobial peptides of the American cockroach
Periplaneta americana
(Linnaeus).
PLoS One
11:
e0155304.
16. Li B, Dewey CN. 2011. RSEM: accurate transcript quantification
from RNA-Seq data with or without a reference genome.
BMC Bioinformatics
12:
1.
17. Misof B, Liu S, Meusemann K, Peters RS, Donath A, Mayer
C,
et al.
2014. Phylogenomics resolves the timing and
pattern of insect evolution.
Science
346:
763-767.
18. Mylonakis E, Podsiadlowski L, Muhammed M, Vilcinskas
A. 2016. Diversity, evolution and medical applications of
insect antimicrobial peptides.
Philos
.
Trans
.
R
.
Soc
.
Lond.
B
Biol.
Sci
.
371:
20150290.
19. Van Huis A, Van Itterbeeck J, Klunder H, Mertens E,
Halloran A, Muir G, Vantomme P. 2013.
Edible Insects: Future
Prospects for Food and Feed Security
. FAO Forestry, Rome.
20. Vilcinskas A. 2013. Evolutionary plasticity of insect immunity.
J
.
Insect Physiol
.
59:
123-129.
21. Vilcinskas A, Mukherjee K, Vogel H. 2013. Expansion of the
antimicrobial peptide repertoire in the invasive ladybird
Harmonia axyridis
.
Proc
.
Biol
.
Sci
.
280:
20122113.
22. Waghu FH, Barai RS, Gurung P, Idicula-Thomas S. 2015.
CAMPR3: a database on sequences, structures and signatures
of antimicrobial peptides.
Nucleic Acids Res
.
44:
D1094-
D1097.
23. Wang X, Fang X, Yang P, Jiang X, Jiang F, Zhao D,
et al.
2014. The locust genome provides insight into swarm
formation and long-distance flight.
Nat
.
Commun
.
5:
2957.
24. Yan T, Yoo D, Berardini TZ, Mueller LA, Weems DC, Weng
S,
et al.
2005. PatMatch: a program for finding patterns in
peptide and nucleotide sequences.
Nucleic Acids Res
.
33:
W262-W266.
25. Ye J, Fang L, Zheng H, Zhang Y, Chen J, Zhang Z,
et al.
2006. WEGO: a Web tool for plotting GO annotations.
Nucleic Acids Res
.
34:
W293-W297.
26. Zhang S, Pang B, Zhang L. 2015. Novel odorant-binding
proteins and their expression patterns in grasshopper,
Oedaleus
asiaticus
.
Biochem
.
Biophys
.
Res
.
Commun
.
460:
274-280.
27. Zhang Y, Sun G, Yang M, Wu H, Zhang J, Song S,
et al.
2011. Chronic accumulation of cadmium and its effects on
antioxidant enzymes and malondialdehyde in
Oxya chinensis
(Orthoptera: Acridoidea).
Ecotoxicol
.
Environ
.
Saf
.
74:
1355-1362.