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Acaricide

For centuries , tick control has been effected using chemical acaricides. Dipping in arsenical compounds was used against R.*microplus and R.*annulatus and worked well to  eradicate these tick species from the USA in early 1900s. But resistance subsequently  developed in the ticks. Organochlorine insecticides such as DDT and  Benezenehexachloride, introduced later, eliminate ticks by preventing acetylcholine  binding to its receptor, hence overRstimulating the sodium channels in neurons.  However, resistance to organochlorine insecticides also developed in*R.*appendiculatus,* R.* microplus* and* R.* decoloratus in Australia and Africa. Furthermore, the residues  persisted in the environment with potential but as yet unquantified implications for  wildlife populations and human health. As a result of these factors their use has been  discontinued.  Organochlorines  were  replaced  by  organophosphates  and  organocarbamates, mainly to control Rhipicephalus*(Boophilus) ticks. They function by  inhibiting acetylcholinesterase thereby inducing continuous nerve firing. Unlike  organochlorines, they do not persist in the environment, however, their toxicity to  vertebrates, combined with emerging resistance in ticks has led to a decline in use.  Amitraz, a member of the formamidine chemical family, is used to control a wide range  of invertebrates and organophosphateRresistant ticks, including R.* microplus,* R.* decoloratus,*R.*appendiculatus*and*R.*evertsi on cattle and other domestic animals. Ticks  on treated animals are usually killed either prior to attachment or within 24 hours of  attachment. Pyrethroids are synthetic compounds that, like most insecticides, affect the  nervous system of the invertebrate. They are costly but effective. Benzoyle phenyl ureas  such as Fluazuron, inhibit chitin formation in B.*microplus, which in turn leads to a  decline in the fecundity and fertility of engorged female ticks. Due to its lipophilic  property Fluazuron is excreted in milk, transmitting chemical protection to the calves.  However, the meat of such cattle cannot be consumed until the residues of the chemical  have waned from the animal’s fat tissues. Spinosad confers about 90% control of R.* microplus. It functions by binding to the nicotinic acetylcholine receptors on the  postsynaptic cell membrane, and is effective against all developmental stages of the tick.

Enzymes:*proteases,*nucleases,*esterases,*lipases,* chitinases***

Enzymes  including  metalloproteases,  nucleotidase/apyrase,  carboxypeptidase,   chitinase,  serine  proteases,  carboxyl  esterase,  endonucleases  and  phospholipase  are   represented  by  80  proteins,  37  of  which  are  metalloproteases,  as  identified  by   conserved  domain  matches  to  the  Zn<dependent  metalloproteases  secreted  by   arthropod  salivary  glands  (CDD:  cd04272,  Superfamily:  cl00064)  (Francischetti  et  al.,   2003).  Most  of  these  contain  the  Pfam  reprolysin  motif  (PF01421).  Metalloproteases   have  been  found  to  be  expressed  abundantly  in  other  hard  ticks    (Chmelař  et  al.,  2008;   Nakajima  et  al.,  2005;  Ribeiro  et  al.,  2006;  Valenzuela  et  al.,  2002a)  as  well  as  soft  ticks   (Mans  et  al.,  2008a)  and  are  thought  to  be  involved  in  anti<blood  clotting  activity   (Valenzuela  et  al.,  2002a).

CHAPTER  1.  LITERATURE  REVIEW
1.1  TICK  BIOLOGY  AND  MEDICAL  AND  ECONOMIC  IMPACT
1.2 RHIPICEPHALUS  APPENDICULATUS  AND  ITS  ROLE  IN  CAUSING  EAST  COAST  FEVER  IN  CATTLE
1.3  TICK  CONTROL 1.4  TICK  SALIVARY  GLAND  FUNCTION  AND  MODULATION  OF  HOST  PATHWAYS
CHAPTER  2.  MATERIALS  AND  METHODS
2.1  PREPARATION  OF  TICK  MATERIAL
2.2  EST  LIBRARY  CONSTRUCTION
2.3  CLUSTERING  AND  ANNOTATION 2.4  BAC  LIBRARY  PREPARATION
2.5  ITM  STABILATE  SEQUENCING  AND  ASSEMBLY
2.6  QUANTIFICATION  OF  RUKA  COPY  NUMBER  IN  R. APPENDICULATUS  GENOMIC  DNA  USING   QUANTITATIVE  REAL  TIME  PCR  (RTUPCR)%
2.7  STRUCTURE  PREDICTION
2.8  IDENTIFICATION  OF  GLYCINEURICH  PROTEINS
2.9  ASSESSMENT  OF  NONUCODING  POTENTIAL  OF  A  TRANSCRIBED  SEQUENCE  USING  PORTRAIT
CHAPTER  3.  ANALYSIS  OF  RHIPICEPHALUS APPENDICULATUS  SALIVARY  GLAND  EXPRESSED   SEQUENCE  TAG  DATABASES (RAGI):  ADDITIONAL  DATA  AND  NOVEL  INSIGHTS
3.1  OVERVIEW
3.2  SUMMARY  OF  GENE  FAMILIES  WITHIN  RAGI
3.3  HOMOLOGUES  OF  TICK  GENES  ENCODING  PREVIOUSLY  IDENTIFIED  VACCINE  CANDIDATES
3.4  UNANNOTATED  TRANSCRIPTS  IN  RAGI
3.5  GLYCINE  RICH  PROTEINS
3.6  CONCLUSION
CHAPTER  4.  NONUCODING  RNA  IN  TRANSCRIBED  SEQUENCES
4.1  BACKGROUND
4.2  EVIDENCE  OF  NONUCODING  RNA  IN  RAGI
4.3  CONCLUSION
CHAPTER  5.  COMPARATIVE  ANALYSIS  OF  GENE  INDICES  GENERATED  FROM  DIFFERENT   IXODID  TICK  SPECIES
5.1  RESULTS
5.2  SEQUENCES  CONSERVED  IN  TICKS
5.3 R. APPENDICULATUSUSPECIFIC  TRANSCRIPTS
5.4  CONCLUSIONS
CHAPTER  6.  ANALYSIS  OF  THE  NUCLEAR  GENOME  OF  R. APPENDICULATUS
6.1  INSIGHTS  INTO  THE  ORGANIZATION  OF  THE  R. APPENDICULATUS GENOME  THROUGH  ANALYSIS   OF  SAMPLE  SEQUENCES
6.2  TRANSPOSABLE  ELEMENTULIKE  SEQUENCES  IN  R. APPENDICULATUS
6.3  CONCLUSION
CHAPTER  7.  CONCLUDING  REMARKS
7.1  FUTURE  AVENUES  FOR  INVESTIGATION

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