[See also 25: no. 12417]
12387 Kabayo, J.P., 2002. Aiming to eliminate tsetse from Africa. Trends in Parasitology, 18 (11): 473-475.
Kabayo: PATTEC Co-ordination Office, Organization of African Unity, PO Box 200032 Addis Ababa, Ethiopia. [[email protected]]
The problem of tsetse-transmitted trypanosomiasis occurs only in sub-Saharan Africa, where it represents a major constraint to socio-economic development. The East African form of sleeping sickness, caused by Trypanosoma brucei rhodesiense, is an acute and fatal disease, whereas the West African form, caused by Trypanosoma brucei gambiense, is generally more chronic and debilitating. The African governments have developed a new initiative, known as the Pan African Tsetse and Trypanosomiasis Eradication Campaign, which seeks to employ an area-wide approach and appropriate fly suppression methods to eradicate tsetse from areas of tsetse infestation, progressively, to ultimately create tsetse-free zones.
12388 Rogers, D.J. & Randolph, S.E., 2002. A response to the aim of eradicating tsetse from Africa. Trends in Parasitology, 18 (12): 534-536.
Rogers: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK. [[email protected]]
An ambitious plan to eradicate tsetse, and therefore tsetse-transmitted trypanosomiases, from Africa was launched at the 36th Organization of African Unity summit meeting (Togo, July 2000) in a bold attempt to re-focus attention on one of Africa's greatest scourges. This plan involves the use of the sterile insect technique to achieve final eradication in areas where the fly is suppressed by more conventional methods (such as traps and targets). In this article the current aims of this project are questioned on historical, ecological, logistical and financial grounds.
12389 Akman, L., Yamashita, A., Watanabe, H., Oshima, K., Shiba, T., Hattori, M. & Aksoy, S., 2002. Genome sequence of the endocellular obligate symbiont of tsetse flies, Wigglesworthia glossinidia. Nature Genetics, 32 (3): 402-407.
Aksoy: Department of Epidemiology and Public Health, Section of Vector Biology, Yale University School of Medicine, 60 College Street, 606 LEPH, New Haven, CT 06510 USA.
Many insects that rely on a single food source throughout their developmental cycle harbour beneficial microbes that provide nutrients absent from their restricted diet. Tsetse flies, the vectors of African trypanosomes, feed exclusively on blood and rely on one such intracellular microbe for nutritional provisioning and fecundity. As a result of co-evolution with hosts over millions of years, these mutualists have lost the ability to survive outside the sheltered environment of their host insect cells. We present the complete annotated genome of Wigglesworthia glossinidia brevipalpis, which is composed of one chromosome of 697 724 base pairs (bp) and one small plasmid, called pWig1, of 5 200 bp. Genes involved in the biosynthesis of vitamin metabolites, apparently essential for host nutrition and fecundity, have been retained. Unexpectedly, this obligate's genome bears hallmarks of both parasitic and free-living microbes, and the gene encoding the important regulatory protein DnaA is absent.
12390 Gariou-Papalexiou, A., Yannopoulos, G., Zacharopoulou, A. & Gooding, R.H., 2002. Photographic polytene chromosome maps for Glossina morsitans submorsitans (Diptera: Glossinidae): cytogenetic analysis of a colony with sex-ratio distortion. Genome, 45 (5): 871-880.
Gooding: Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada. [[email protected]]
Photographic polytene chromosome maps from trichogen cells of pharate adult Glossina morsitans submorsitans were constructed. Using the standard system employed to map polytene chromosomes of Drosophila, the characteristic landmarks were described for the X chromosome and the two autosomes (L1 and L2). Sex-ratio distortion, which is expressed in male G. m. submorsitans, was found to be associated with an X chromosome (XB) that contains three inversions in each arm. Preliminary data indicate no differences in the fecundity of XAXA and XAXB females, but there are indications that G. m. submorsitans in colonies originating from Burkina Faso and Nigeria have genes on the autosomes and (or) the Y chromosome that suppress expression of sex-ratio distortion.
12391 Haddow, J.D., Poulis, B., Haines, L.R., Gooding, R.H., Aksoy, S. & Pearson, T.W., 2002. Identification of major soluble salivary gland proteins in teneral Glossina morsitans morsitans. Insect Biochemistry and Molecular Biology, 32 (9): 1045-1053.
Pearson: Department of Biochemistry and Microbiology, Petch Building, University of Victoria, Victoria, BC, Canada V8W 3P6. [[email protected]]
Salivary glands of tsetse flies (Diptera: Glossinidae) contain molecules that are involved in preventing blood clotting during feeding as well as molecules thought to be intimately associated with trypanosome development and maturation. Here we present a protein microchemical analysis of the major soluble proteins of the salivary glands of Glossina morsitans morsitans, an important vector of African trypanosomes. Differential solubilization of salivary proteins was followed by reverse-phase, high-performance liquid chromatography (HPLC) and analysis of fractions by 1-D gel electrophoresis to reveal four major proteins. Each protein was subjected to amino acid microanalysis and N-terminal microsequencing. A protein chemical approach using high-resolution 2-D gel electrophoresis and mass spectrometry was also used to identify the salivary proteins. Matrix-assisted, laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and quadrupole time-of-flight (Q-TOF) tandem mass spectrometry methods were used for peptide mass mapping and sequencing, respectively. Sequence information and peptide mass maps queried against the NCBI non-redundant database confirmed the identity of the first protein as tsetse salivary gland growth factor-1 (TSGF-1). Two proteins with no known function were identified as tsetse salivary gland protein 1 (Tsal 1) and tsetse salivary gland protein 2 (Tsal 2). The fourth protein was identified as Tsetse antigen-5 (TAg-5), which is a member of a large family of anti-haemostatic proteins. The results show that these four proteins are the most abundant soluble gene products present in salivary glands of teneral G. m. morsitans. We discuss the possible functions of these major proteins in cyclical transmission of African trypanosomes.
12392 Haines, L.R., Haddow, J.D., Aksoy, S., Gooding, R.H. & Pearson, T.W., 2002. The major protein in the midgut of teneral Glossina morsitans morsitans is a molecular chaperone from the endosymbiotic bacterium Wigglesworthia glossinidia. Insect Biochemistry and Molecular Biology, 32 (11): 1429-1438.
Pearson: Department of Biochemistry and Microbiology, Box 3055 Petch Building, University of Victoria, Victoria, British Columbia, Canada V8W 3P6. [[email protected]]
Molecules in the midgut of the tsetse fly (Diptera: Glossinidae) are thought to play an important role in the life cycle of African trypanosomes by influencing their initial establishment in the midgut and subsequent differentiation events that ultimately affect parasite transmission. It is thus important to determine the molecular composition of the tsetse midgut to aid in understanding disease transmission by these medically important insect vectors. Here, we report that the most abundant protein in the midguts of teneral (unfed) Glossina morsitans morsitans is a 60 kDa molecular chaperone of bacterial origin. Two species of symbiotic bacteria reside in the tsetse midgut, Sodalis glossinidius and Wigglesworthia glossinidia. To determine the exact origin of the 60 kDa molecule, a protein microchemical approach involving two-dimensional (2-D) gel electrophoresis and mass spectrometry was used. Peptide mass maps were compared with virtual peptide maps predicted for S. glossinidius and W. glossinidia 60 kDa chaperone sequences. Four signature peptides were identified, revealing that the source of the chaperone was W. glossinidia. Comparative 2D gel electrophoresis and immunoblotting further revealed that this protein was localized to the bacteriome and not the distal portion of the tsetse midgut. The possible function of this highly abundant endosymbiont chaperone in the tsetse midgut is discussed.
12393 Hao, Z.G. & Aksoy, S., 2002. Proventriculus-specific cDNAs characterized from the tsetse, Glossina morsitans morsitans. Insect Biochemistry and Molecular Biology, 32 (12): 1663-1671.
Aksoy: Department of Epidemiology and Public Health, Section of Vector Biology, Yale University School of Medicine, 60 College Street, 606 LEPH, New Haven, Connecticut 06510, USA. [[email protected]]
Peritrophic matrix (peritrophic membrane or PM) is an important structure in the gut of most insects at some stage in their development. It is composed of chitin, proteins and proteoglycans. Multiple roles for the PM ranging from partitioning of digestive enzymes and food to protection of gut epithelial cells from viral and parasitic invasion have been proposed. While most adult members of Diptera have a Type I PM synthesized in response to a blood meal, the medically and agriculturally important vector insect, tsetse, has a sleeve-like Type II PM which is constitutively synthesized by cells in the proventriculus (cardia). Using a differential hybridization approach, we have identified three abundant cDNAs from a proventriculus cDNA library of Glossina morsitans morsitans: GmPro1, GmPro2 and GmPro3. DNA sequence analysis indicates that GmPro1 and GmPro2 share similarities with the peritrophin-15 family of larval PM proteins, while GmPro3 is a member of the serine protease family. Northern analysis indicates that transcripts for all three cDNAs are preferentially expressed in the proventriculus tissue. The expression profile of these genes in response to the presence of trypanosome indicates that transcription of GmPro1 is increased in the presence of parasites (immune sensitive), while the other two are not affected. Western analysis using antibodies developed against the recombinant GmPro2 shows its primary localization in the gut to be within the peritrophic matrix structure. We discuss the molecular characteristics of these proventriculus specific cDNAs and their products as well as their potential role for vector control studies.
12394 Pollock, J.N., 2002. Observations on the biology and anatomy of Curtonotidae (Diptera: Schizophora). [Glossinidae] Journal of Natural History, 36: 1725-1745.
Pollock: 25 Palmeira Mansions, Church Road, Hove, East Sussex BN3 2FA, UK.
New information concerning the biology and anatomy of Cyrtona spp. and Curtonotum quinquevittatum (Curtonotidae, Ephydroidea) is given. During the hot, dry season the latter species leaves its warthog burrow refuges at night. Cyrtona spp. rest in densely shaded humid habitats during the same season, dispersing in the cooler seasons. Postabdominal sclerites and internal anatomy of the male abdomen are described for both genera. A suggested ground plan of the Ephydroidea is outlined. The families Gasterophilidae, Glossinidae and Hippoboscidae are regarded as collectively the sister group of Oestridae, and based in part on the comparative anatomy of Curtonotidae, the whole complex is seen as deriving from early ephydroids, not from Calyptratae.
12395 Wren, B.W., 2002. Deciphering tsetse's secret partner. Nature Genetics, 32 (3): 335-336.
Wren: Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK. [[email protected]]
The genome sequence of the bacterial endosymbiont Wigglesworthia glossinidia that resides in the gut of the tsetse fly has been determined. Because the tsetse fly relies on this bacterium for fertility and nutrition, this information may be useful in reducing fly populations and halting the spread of the deadly African sleeping disease.
12396 Yan, J., Cheng, Q., Narashimhan, S., Li, C.-B. & Aksoy, S., 2002. Cloning and functional expression of a fat body-specific chitinase cDNA from the tsetse fly, Glossina morsitans morsitans. Insect Biochemistry and Molecular Biology, 32 (9): 979-989.
Aksoy: Department of Epidemiology and Public Health, Section of Vector Biology, Yale University School of Medicine, New Haven, CT 06510, USA. [[email protected]]
A chitinase cDNA, GChit1 was isolated from Glossina morsitans morsitans and shown to be specifically expressed in fat body tissue. GChit1 is encoded by a 1.6 kb mRNA with a putative open reading frame (ORF) of 460 amino acids (predicted pI = 7.5, m.w. = 51kDa) that contains a signal peptide domain and two potential N-linked glycosylation sites. The ORF exhibits homology to various chitinases characterized from insects. It has the conserved catalytic site residues and the cysteine-rich 3'-end domain associated with chitin binding although the serine/threonine rich domain is apparently missing. Southern blot data indicate that GChit1 is present as a single-copy locus in the Glossina genome. Northern analysis indicates that transcripts for GChit1 can be detected only from the fat body of adult flies. Similarly, chitinase activity could be detected in fat body but not in the gut or salivary gland tissues. The full-length cDNA was expressed in vitro in Drosophila S2 cells and the molecule was produced in a soluble form. Polyclonal antibodies raised against recGChit1 could recognize a protein of about 50 kDa in adult fat body extracts. In addition to fat body, chitinase protein was detected by Western analysis from the milk gland tissue of pregnant females as well as from the intrauterine larval and pupal developmental stages. No chitinase specific mRNA transcripts could be observedhowever, from larvae and pupae. The intrauterine larva of tsetse may receive the protein from its mother via the milk gland route. The molecular characteristics of GChit1 and its product and the potential role of this chitinase in tsetse biology are discussed.
12397 Evans, W.G. & Gooding, R.H., 2002. Turbulent plumes of heat, moist heat, and carbon dioxide elicit upwind anemotaxis in tsetse flies Glossina morsitans morsitans Westwood (Diptera: Glossinidae). Canadian Journal of Zoology, 80 (7): 1149-1155.
Evans: Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9. [[email protected]]
The roles and interactions of turbulent plumes of heat, moist heat, and carbon dioxide in mediating upwind flight of adult tsetse flies (Glossina morsitans morsitans) were investigated using a wind tunnel in a constant-environment chamber. Heat fluctuations in the plume that were detected by a thermocouple and displayed as oscilloscope traces allowed direct visualization of the structures of the plumes. Significantly more flies flew upwind when exposed to plumes of (i) carbon dioxide (0.0051 percent above background) and air (58 percent relative humidity) compared with air alone; (ii) carbon dioxide and heated air (35 percent relative humidity and temperature fluctuating up to 0.09 °C above background) compared with carbon dioxide and air; and (iii) carbon dioxide and moist (82 percent relative humidity) heated air (temperature fluctuating up to 0.05 °C above background) compared with carbon dioxide and heated air. However, there were no significant differences in upwind flight of flies exposed to plumes of (i) air compared with humidified air (65 percent relative humidity); (ii) carbon dioxide and heated air compared with heated air alone; and (iii) carbon dioxide and moist heated air compared with moist heated air alone. Recorded temperature fluctuations in heat plumes transported downwind from a tethered steer in a pasture showed patterns similar to those produced in the wind-tunnel plumes. These results suggest that host emissions of carbon dioxide alone and combined heat and moisture carried downwind by low-velocity winds elicit upwind anemotaxis in tsetse flies, which distinguish these emissions from a background of lower atmospheric levels.
12398 Krafsur, E.S. & Endsley, M.A., 2002. Microsatellite diversities and gene flow in the tsetse fly, Glossina morsitans s.l. Medical and Veterinary Entomology, 16 (3): 292-300.
Krafsur: Department of Entomology, Iowa State University, Ames IA 50011, USA. [[email protected]]
Tsetse flies occupy discontinuous habitats and gene flow among them needs to be investigated in anticipation of area-wide control programs. Genetic diversities were estimated at six microsatellite loci in seven Glossina morsitans submorsitans populations and five microsatellite loci in six G. m. morsitans populations. Nei's unbiased diversities were 0.808 and 76 alleles in G. m. submorsitans and 0.727 and 55 alleles in G. m. morsitans. Diversities were less in three laboratory cultures. Matings were random within populations. Populations were highly differentiated genetically. Populations were strongly subdivided, as indicated by fixation indices (F (ST)) of 0.18 in G. m. morsitans and 0.17 in G. m. submorsitans. Thirty-five percent of the genetic variance in G. m. submorsitans was attributed to differences between populations from The Gambia and Ethiopia. All available genetic evidence suggests that genetic drift is much greater than gene flow among G. morsitans s.l. populations.
12399 Ruxton, G.D., 2002. The possible fitness benefits of striped coat coloration for zebra. Mammal Review, 32 (4): 237-244.
Ruxton: Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8GG, UK. [[email protected]]
The literature addressing evolutionary reasons for the striped patterns of zebra coats is reviewed here. Possible mechanisms, and the evidence for and against them, are discussed. These mechanisms span four general themes: protection from predators; social functions; thermoregulation; and protection from tsetse flies. The last is the only hypothesis that has been tested experimentally, and the results of these tests are inconclusive. Additionally or alternatively, although stripes apparently increase zebra visibility in daylight, it is at least plausible that they provide effective cryptic protection from predators in poor light, although critical testing has not been attempted. Other related evolutionary questions are raised and suggestions made for future research.
[See also 25: nos. 12387, 12388, 12421]
12400 Mamuye H. & Dawit A., 2002. Pathogenicity of Ethiopian isolates of Metarhizium anisopliae and Beauveria bassiana against the tsetse fly, Glossina morsitans morsitans. Pest Management Journal of Ethiopia, 6: 23-29.
Mamuye: Ethiopian Health and Nutrition Research Institute, PO Box 1242, Addis Ababa, Ethiopia. [[email protected]]
Entomopathogenic fungi, Metarhizium anisopliae EE, M. anisopliae MM, Beauveria bassiana FF, B. bassiana GG and B. bassiana AK isolated from different sources in Ethiopia were evaluated against the tsetse fly, Glossina morsitans morsitans in the laboratory. Metarhizium anisopliae isolates EE and MM caused mortalities of 96.67 percent and 73.33 percent respectively, while B. bassiana isolates coded as FF, GG and AK showed percent mortalities of 75.00, 63.33 and 53.33, respectively. Beauveria bassiana FF was significantly better than B. bassiana AK (P<0.05). Spore production of presumably promising isolates, M. anisopliae MM and EE, was determined on solid substrates, whole grains of rice, wheat, barley and sorghum. Both isolates grew best on rice giving a yield of 1.42×109 spores/g of rice for M. anisopliae MM and 1.62×109 spores/g of rice for M. anisopliae EE. No relationship was observed between moisture content of grain types and spore yield (P>0.05). The potential of the isolates for the control of tsetse flies is discussed.
12401 Mihok, S., 2002. The development of a multipurpose trap (the Nzi) for tsetse and other biting flies. Bulletin of Entomological Research, 92 (5): 385-403.
Mihok: 388 Church Street, Russell, Ontario, K4R 1A8, Canada. [[email protected]]
New trap designs for tsetse (Glossinidae), stable flies (Muscidae: Stomoxyinae), and horse flies (Tabanidae) were tested in Kenya to develop a multipurpose trap for biting flies. Many configurations and colour/fabric combinations were compared with a simplified, blue-black triangular trap to identify features of design and materials that result in equitable catches. New designs were tested against conventional traps, with a focus on Glossina pallidipes and G. longipennis, Stomoxys niger, and Atylotus agrestis. A simple design based on minimal blue and black rectangular panels, for attraction and contrast, with a trap body consisting of an innovative configuration of netting, proved best. This 'Nzi' trap (Swahili for fly) caught as many or significantly more tsetse and biting flies than any conventional trap. The Nzi trap represents a major improvement for Stomoxyinae, including the cosmopolitan species Stomoxys calcitrans, with up to eight times the catch for key African Stomoxys spp. relative to the best trap for this group (the Vavoua). Catches of many genera of Tabanidae, including species almost never caught in traps (Philoliche), are excellent, and are similar to those of larger traps designed for this purpose (the Canopy). Improvements in capturing biting flies were achieved without compromising efficiency for the savannah tsetse species G. pallidipes. Catches of fusca group tsetse (G. longipennis and G. brevipalpis) were higher or were the same as catches in good traps for these species (NG2G, Siamese). Altogether, the objective of developing a simple, economical trap with harmonized efficiency was achieved.
