Figure 1.
The major morphological classes of trypanosomatids.
Diagrams of six common, easily distinguished trypanosomatid morphologies [3]. A. Morphologies with a flagellum laterally attached to the cell body. B. Morphologies with a free flagellum (no lateral attachment of the flagellum to the cell body extending beyond the flagellar pocket neck). Metrics used to record cell morphology are indicated (cell body length, free flagellum length, kinetoplast–posterior distance (KP) and nucleus–posterior distance (NP)). Genera in which each morphology occurs [28] in are indicated, monophyletic genera [25] are underlined. C. Amastigote morphology, which does not have a long, motile, flagellum. D. Key. Structures associated with the flagellum (the basal body/pro-basal body pair (BB), flagellar pocket (FP), Axoneme (Ax) and paraflagellar rod (PFR)) are indicated.
Figure 2.
Trypanosomatid morphology, life cycle and phylogeny are indicative of two morphological superclasses.
A. Phylogeny of 12 representative trypanosomatids inferred from the small subunit (SSU) rRNA gene sequence, rooted with the outgroup B. saltans. Values at nodes indicate bootstrap support. The apparent paraphyly of Trypanosoma is a well documented example of a long branch attraction artefact [212]. B. Morphological classes attained though the 12 trypanosomatid life cycles. a[3], b[1], c[8], d[6], e[9], f[5], g[7], h[213], i[36], j[195], k[214], l[215], m[216], n[217], o[187], p[218], r[219], s[213]. C. Life cycle type and transmission route from the insect host in the 12 trypanosomatid life cycles. Relevance of the L. tarentolae amastigote in the life cycle [220], [221] and the transmission pathway [213] are debated. D. Phylogeny of the 12 trypanosomatids inferred from the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH), rooted with the outgroup B. saltans. Values at nodes indicate bootstrap support.
Figure 3.
Conservation of known cytoskeletal-associated proteins between liberforms and juxtaforms.
Summary of cytoskeleton-associated proteins, the organism in which they were originally identified (red), and possession (black) or absence (white) of a homolog, identified by reciprocal best BLASTp. PFR1 and 2 were originally identified in Euglena gracilis. a[222], b[223], c[4], d[224], e[225], f[226], g[227], h[228], i[229], j[230], k[231], l[232], m[233], n[234], o[235], p[236], r[237], s[238], t[239].
Figure 4.
Diversity and correlation of morphological features in species with a juxtaform morphology.
Data are colour coded by genus and host, Trypanosoma isolates are from either the vertebrate bloodstream of the insect host and all Blastocrithidia and Strigomonas isolates are from the insect host. n numbers for each plot are indicated in the top left. Solid black lines indicate the linear regression fit line for bloodstream Trypanosoma; the regression coefficient (R2) is shown each plot. Axenic procyclic form T. brucei dimensions [39], [41] and bloodstream form dimensions are indicated with a open data point.
Figure 5.
Diversity and correlation of morphological features in species with a liberform morphology.
Data are colour coded by genus, all isolates are derived from the insect host. n numbers for each plot are indicated in the top left. Solid black lines indicate the linear regression fit line of data for all genera combined; the regression coefficient (R2) is shown each plot. Axenic promastigote L. mexicana dimensions [38] are indicated with an open data point.
Figure 6.
Range of cell body and flagellum length within isolates of juxtaforms and liberforms.
Histograms of the ratio of the cell body length range within an isolate to the mean (the cell body ‘length range ratio’) (A and C) and flagellum length range ratio (B and D) for juxtaforms (A and B) and liberforms (C and D). n numbers for each plot are indicated in the bottom right. Vertical dashed line indicates where either proliferating axenic procyclic T. brucei trypomastigotes [39], [40] or L. mexicana promastigotes [38] would be positioned on the cell body length plots.
Figure 7.
Diversity of erythrocyte dimensions of hosts from which bloodstream Trypanosoma isolates were derived.
A. Diagram of erythrocyte measurements used to characterise their shape. B. Correlation of erythrocyte major axis and minor axis from vertebrate hosts of Trypanosoma parasites, subcategorised by class. n numbers for each genus are indicated in the bottom left. Homo sapiens erythrocyte dimensions are indicated with an open data point.
Figure 8.
Limits on bloodstream-inhabiting trypanosomatid morphology relative to host erythrocyte dimensions.
Correlations of trypanosomatid cell body length, cell body width, free flagellum length and flagellum length with host erythrocyte major axis and minor axis. Solid data points indicate host species-specific erythrocyte data, where available, open data points indicate the average of erythrocyte data available for the host genus. Solid lines indicate the linear regression fit line for genus data; the regression coefficient (R2) is shown on each plot. Dashed lines indicate the line along which trypanosomatid and host erythrocyte dimensions would be equal. T. binneyi data points are circled with a dotted line. n numbers for each plot are indicated in the bottom right.
Figure 9.
Limits on kinetoplast position in bloodstream-inhabiting trypanosomatid species.
Histograms of kinetoplast-posterior (KP) distance (A and C) and the ratio of KP distance to cell body length (B and D) for all trypanosomatid isolates from the bloodstream (A and B) and a separate set of only mammalian-infective African trypanosomes (C and D). n numbers for each plot are indicated in the top right. Vertical dashed lines indicate where axenic PCF and BSF T. brucei would be positioned on these plots.
Figure 10.
Cell body morphogenesis of a promastigote and trypomastigote through the cell cycle.
Cell growth is indicated by arrows with a perpendicular bar, the bar indicates the region that grows. Cell remodelling is indicated by barb-headed arrows. The path of furrow ingression is indicated by dashed arrows. The old and new flagellum are coloured red and turquoise respectively. A. Summary of the morphological changes of an example liberform (promastigote L. mexicana) through the cell cycle [38]. The cell grows in length, then remodels the cytoskeleton during cytokinesis. B. Summary of the morphological changes of an example juxtaform (trypomastigote procyclic T. brucei) through the cell cycle [39], [81], [240]. The cell first grows in length then in width prior to cytokinesis.