The cytology of tritrichomonas as revealed by the electron microscope

THE CYTOLOGY O F TEITRICHOlfONAS

ELECTRON MIC'ROSCOPE AS REVEALED BY THE

EVERETT ANDERSOPU' AND 11. W. BEAMS Department of Zoology, State LTnRersity of Iowa,

Iowa Ci ty

FIFTEEN FIGURES

Although many electron microscope studies of finc structure of unicellular organisms have been reported, relatively few observations have been made on the complex organelles of tritrichomonads. I n an earlier communication (Anderson, ' 55) the ultrastructural organization of such highly differentiated organelles was studied by methods then available. a s revealed here recent advancements in fixation, microtomy and microscopy have made it possible to learn more about the submicroscopic organization of the organelles and their relationship to one another. I t is f u r this reason that we here present the results of this invmtigation.

MATERIALS AND METHODS

The organisms used in this investigation, Trif richommans type-nzuris, were obtained from the caecum of thc golden hamster and fked for 30 minutes in a 1% osmium tetroxide solution, buffered at pH 8.5 with acetate veronal buffer. They were subsequently dehydrated, infiltrated, embedded in meth-

'The contents of this paper were presented at a Round Table Discussion on The Ultrastructure of Protozoa held jointly by the Society of Protozoologists and the American Society of Zoologists a t the American Institute for Biological Sciences meeting a t Stanford University; Stanford, California, August 2629,1957. Supported by a grant (RG-4706 and 5479) from the National Institutes of IIenlth, United States Public Health Service.

205

206 EVERETT AFDERSON AND 33. VC'. BEAMS

acryla te, sectioned and observed with a Pliilips Electron Microscope, model 1 0 0 - i ~ ~

For light microscopy, a few organisms were fixed in Schaudinn's fluid with 5% acetic acid added and stained with iron hematoxj-liiz.

RESULTS

Light 97tic?-Oscqq

Tr-itrichoimms type-nmris is p:Triform in shape ; it tapers posteriorly and is approxiinaiely 16 p in length. The organelle systems of a typical trophic individual are indicated in figure 1. The blepharoplast complex (E) is located at the anterior end of the major axis of the organism, and serves as the point of origin for ihe follo~ving organelles: t h e e anterior flagella (AF), recurrent flagellum (RE'): accessory filament (ACF), undulating membrane ( UBf), costa (C) , asostyle (AX), parabasal body (PB) and parabasal filament (PF). The axostyle is surrounded by a chroiuatic ring (CR) near the point of apparent emergence from the posterior. end of the body.

The nucleus (N) is oval in shape and located in the anterior third of the body. Within the nucleus are sniall chromatin granules and a nucleolus (NCL), usually encompassed by a clear area. Surrounding the nucleus is a mass of basopliilic material first described by Kofoid and Swezy ( '15) and subsequently by Samuels ('41).

Scattered throughout the cytoplasm are darkly staining granules, referred to by certain investigators as cliromatic granules (CG). Many of these are arranged in rows along the costa where they are called paracostal granules (E'CG). For a detailed description of Tritrichowtonas type-nzzlris the rearicr is refcrred to Wenrich, ('21) arid Kirby and Honig- berg, ('49).

aThc authors wish to express their thanks t o the Departinent of Anatomy of the University of Colorado Medical Center for the use of the Philips Electron Microscope.

Fig. 1 Diagrammitic drawing of Il'ritrichoni0nn.s murzs. >4F, aiiterior flngclln ; R, blepharoplast ; K, nacleus; KLYi, nualcolus ; PP, p:tr:tlsnsnl f i lammt ; AX, axovtyle ; CG, chromatir grnriiilo ; C'R, chromatic ring; KF, recurrent flagellum; PB, p a r a h a d body ; C, costa; Uhl , undulating membrane; PCC, paraeostal granule ; ACF, accessory filameut.

007

208 EVERETT ANDERSON APU’D H. W. REAMS

Electrom Microscopy

Blepharoplnst. Figures 3, 5, 6 and 7 are electron micrographs of sections through the anterior end of the organism showing the relationship of the costa and flagella to one another in the region of the blepharoplast. These organelles appear to end in a dense collection of small granules describing a cytoplasmic area of relatively high density (figs. 5 and 6, b) . The flagella are anchored to basal bodies (kinetosomes) which consist essentially of prolongations of the flagellar filaments below the surface membrane. The proximal ends of the flagellar basal bodies seem to be in close association with the costa (figs. 2, 3 and 5, c) ; however, whether a morphological connection exists between them cannot be stated since few sections of this small region have been obtained.

The flagella of T‘ritrichomonas exhibit an ultramicroscopic structural pattern similar to that found for flagella and cilia in othcr cell types. In longitudinal see- tion the slightly curved flagella are composed of longi tudin- ally oriented filaments embedded in a matrix whose density closely approximates that of the surrounding cytoplasm (figs. 2, 3, 5, and 6, af) . These filaments are enclosed by a smooth membrane which is continuous with the plasma rncmbrane. In cross section the filaments are seen to have a geometrical pattern of nine pairs spaced around the periphery of two centrally located ones (fig. 4, af). I n longitudinal sections the central filaments appear to approach the basal bodies without interruptions (figs. 2 and 3 ) . A row of small granules about 180 A in diameter are located in the basal portions (figs. 2, 3 and 7, cf) ; the nature and significance of these granules is unknown.

Recurrent flagellum, ‘ ‘nccessory filament’’ and undulatimg rwmbrame. Two structures, the recurrent flagellum and “accessory filament, ’) are described by light microscopists as forming a stiffening rib along the outer border of the undulat-

Anterior flagella.

Since this paper was submitted for publication, additional observations reveal that the costa extends from the basal body of the recurrent flagellum; the parabasal filament from one of the basal bodies of the anterior flagelhe. An account of these observations i s being preparcd f o r publication.

CYTOLOGY O F TRITRICHOMOITAS 209

ing membrane. The arrangement of the internal filaments of the recurrent flagellum is similar to that described for the anterior flagella (fig. 8, rf).

The often cited “accessory filament, ” located parallel to the recurrent flagellum, may be seen at dz in figure 8. It appears, as has been described by light microscopists, to be larger than the recurrent ff agellum. This organelle, however, seems to be devoid of any filamentous structure. It usually appears, in electron micrographs, to be composed of a number of granules located in a zone between the recurrent flagellum and the fibrous sheet-like component designated as the undulating membrane-proper (fig. 8, ump).

Because of the spiral nature of the undulating membrane it is difficult to obtain thin sections longitudinal to the long axis of the organelle. A transverse section through a fold of the undulating membrane may be seen in figure 8. The fibrous sheet-like component, here oriented perpendicular to the long axis of the undulating membrane, is embedded in a granular matrix. The components of the undulating membrane, i.e., the filaments of the recurrent flagellum, ‘ ‘accessory filament’ ’ and fibrous sheet-like component, are all enclosed by a single- layered membrane.

From relatively low power electron micrographs this organelle displays an obvious axial periodicity (fig. 6, c). At higher magnifications (figs. 8 and 9) the costa is revealed to be more complex possessing a linear array of small cross bands of relatively high density alternating with broaded ones of lower density. I n figure 9 the broad bands can be seen bisected by a narrow dense line.

I n figure 8 just lateral to the costa is seen a collcetion of small granules (g), the significance of which is obscure.

Paracostal bodies ( g r a d e s ) . The paracostal bodies, when viewed with the electron microscope, display a complex morphology (fig. 8, pc). Their internal structure is seen to be composed of a system of vesicles and granules of varying sizes. This internal system is bounded by a double membrane envelope which is surrounded by an in close contact with a fine reticular-like network.

Costa.

210 EVERETT ANDERSON AKD H. TV. BEAMS

Axostyle a d “chromatic riqq.’’ The axostyle is described by light microscopists as a hyalinc rod extending through the body of the organism. This organelle is divided into two parts: (1) the capitulum, the expanded cup-like area at the level of the nucleus which projects anterior to the blepharoplast complex and (2) the shaft o r trunk, extending from a position posterior to the nucleus to the end of the organism where it tapers to a point.

It may be observed at pbc in figure 3 that the anterior portion of the capitulum extends beyond the region of the blepharoplast and is slightly reflected over it. For convenience in describing the axostyle, the portion of the capitulum and shaft or trunk se-ment adjacent to the nucleus will be referred to as the central aspect ; that portion nearest the internal plasma membrane will be referred to as the peripheral portion. From electron micrographs of a slightly tangential section made at a level anterior to the nucleus the centra.1 (ca) and peripheral aspects (pa) of the organelle may be seen (fig. 7). In the region of the blepharoplast complex the two portions appear to approximate one another closely and as they pass posteriorly become farther apart at the level of the nucleus. The central part at the level of the nucleus appears discontinous while the peripheral portion seems to be continuous. Figure 14 illustrates a tangential section through the axostyle (ax) a t the level of the nucleus where it appears C-shaped; appar- ently only the peripheral part of its greater curvature is shown. The cup of the C-shaped axostyle contains a number of dense granules. The surrounding cytoplasm appears to be continuous with that seen in the axostyle, displaying a similar density. From a section made at a level just posterior to the nucleus (fig. 10) the central and peripheral aspects can be seen to continue to the posterior end of the organism. The tip of the axostyle is surrounded by the limiting plasma niem- brane (fig. 11).

The axostyle appears to be limited by a single-layer of many fine filaments oriented obliquely to its long axis (figs. 10

CYTOLOGY O P THITRICH0”INAS 211

and 14). These filaments are approximately 140 A in thick- ness.

Near the posterior end of the axostyle is usually seen a dense ring referred to by light microscopists as the “chromatic ring.” From electron micrographs it apears to be composed of a number of membranes whose surfaces are studded with small granules o r rod-like particles (fig. 11, aer). These membrane systems are similar to elements of the endoplasmic reticulum.

I n figure 12 the parabasal filament (pf) appears to have its origin in the blepharoplast complex (b), and at this magnification exhibits an axial periodicity ; at higher magnifications the complexity of the periodicity can be seen (fig. 14, pf) . The filament appears to be composed of areas of material of high density alternating with broader ones of lower density.

I n juxtaposition and parallel to the parabasal filament is the parabasal body (figs. 12, 14, and 15, pb). This organelle is seen to be composed of a number of distinct smooth double- membrane lamellae in parallel array and a system of thick- walled vesicles located at their borders. The menibrane coni- ponents often display many constrictions along their longitudinal axis and dilatations are usually seen at their ends (figs. 10, 12 and 13).

The nucleus is surrounded by a double membrane envelope, interrupted at intervals by pores (fig. 7, np). The nucleoplasni is composed of fine particulate matter in the form of granules o r rod-like particles (figs, ?‘,lo, 14 and 15). The nucleolus appears to be composed of closely aggregated dense granules or rod-like particles (fig. 15, ncl).

Organisms fixed and stained with basic stains often reveal a mass of basophilic material surrounding the nucleus. From the electron micrographs this mass is seen to be composed of distinct membranes or cistcrnal units having at their surfaces small dense granules o r rod-like particles (figs. 10 and 15, er). The arrangement of this material in relation to the nucleus is

PQrabasal filarne+?,t mad body.

Nucleus amd “nudear cloztd. ”

212 EVERETT AKOEtiSOX AND H. W. REAMS

isomorphic with the basophilic material described by Kofoid and Swezy ( ’15) as the “ extra nuclear cloud’ ’ and by Samuels ( ’41) as “ a special cytoplasmic area.” Similar membranes are seen scattered in the cytoplasm with no perferred orienta- tion (fig. 6, er) as wcll as clusters of similar granules or rod- like particles (figs. 6 and 8, er,). The morphological organization of this material is similar to the component described as the endoplasmic reticulum and small particulate component in many different cell types (Palade, ’56; ’58).

Mitochondria. The mitochondria appear to be limited by a single membrane of low density. The internal structure seems to he composed of a few circular profiles which may be sections through tubular-like structures (figs. 7 and 10, m).

DISCUSSIOS

In tlie classical paper on tritrichomonads by Kofoid and Swezy ( ’15), the blepharoplast was reported to be composed of two parts, the centrosome and basal granules. Since that time many investigators have envisioned that the complex area is the central point of origin for the flagella, undulating membrane, costa, axostyle, parabasal body and parabasal filament; it has been referred to as a “granular organelle’’ (Buttrey, ’54). Each basal granule o r kinetosome is thought to be associated with a particular organelle arising at that point. The present study also suggests that the flagella, costa and parabasal filament arise within the area of the blepharoplast complex and demonstrates basal bodies associated with flagella.

The composition of thc margin of the undulating membrane in this group has been a difficult problem and rcany conflicting opinions concerning it exist in the literature (See Kirby, ’44). The area designated as the “accessory filampnt” has been showii by light microscopists to give a different staining i-e- action than that of the recurrent flagellum. The low-power electron micrographs presented by Anderson ( ’ 5 5 ) and the relatively high-power ones illustrated in the present study

CYTOLOGY OF TRITRICHOMONAS 213

suggest a niorphological difference in this area when compared with the recurrent flagellum.

Investigations dealing with the ultramicroscopic structure of undulating membranes associated with a flagellar structure have revealed a similarity between organelles in quite un- related cell types. For example Anderson, Saxe and Beams ('56) found a non-fibrillar material composing the body of the undulating membrane of Trypanosoma epuiperdum which is closely associated with the filaments of the marginal flagellum. A similar observation was made on the undulating membrane of the spermatozoa of Bufo arenarttm by Burgos and Fawcett ( '56). The function of the non-fibrillar material located in the undulating membrane of T. equiperdum is not known; however, Fawcett ('58) speculates from his studies on Bufo and Triturus that the non-fibrillar material "pro- vides some degree of stiffness or that it serves as a weighted keel to counter balance torque and stabilize the spermatozoon during its swimming movements. " Very little can be stated with respect to the fibrous sheet-like component of the undulating membrane-proper of Tritrichowzonas. It may be pointed out that this area is morphologically similar to the myonemes described for Steator polymorphus and Spirostumunz by Randall ( '56; '57). Whether the energy for contraction, producing the undulatory movement, is derived from all of the components associated with filaments of the recurrent flagellum or whether it is derived only from the filamcnts of the recurrent flagellum is not accrtainable from this data.

The electron microscope has demonstrated an axial periodicity in many structures, namely trichocysts, muscle, collagen' fibrin, ciliary rootlets and others (Schmitt, Hall and Jakus, '42; Fawcett and Porter, '54; Potts, '55; Schmitt, '56; Beams, Tahmisian and Devine, '57 ; Pitelka and Schooley, '58). Ludvik ( '54) presented electron micrographs of whole mounts of TritrichornoNnas foetus showing the costa to possess a number of striations. Anderson ('55; '57) presented evi-

214 EVERETT ANDERSOB AND H. W. BEAMS

dence from sectioned material to show that the costa was composed of a series of discs embedded in a matrix. With the present high resolution electron niicrographs the general picture is essentially the same but more complex.

Nany investigators are of the opinion that the costa is a supporting structure. This is borne out by its ultramicroscopic structure which resembles collagen, ciliary rootlets and other known supporting structures. This similarity in structure to certain other biological materials is interesting because it must mean that the same laws that operate in protozoa are governing the organization of macromolecules throughout the animal kingdom.

The paracostal bodies (granules) belong to that ill-defined group of cytoplasmic structures called by students of tritrichomonads “chromatic granules. ” From the literature it is evident that many workers have been reluctant to assign a function to these bodies ; however, Allexeieff ( ’24) suggested that they were mitochondria and Uuttrey (’54) believed them to be waste products. The organization of structure displayed in electron micrographs by these organelles, i.e., the double limiting membrane envelope, internal granules and vesicles, suggest that of mitochondria. One may speculate that these organelles may be modified or specialized mitochondria carry- ing an array of enzyme systems directly o r indirectly related to the general metabolism of the organism. Before this suggestion is proven, however, more biochemical and physiologi- cal information is needed.

Much discussion is found in the literature concerning the origin, morphology and reorganization of the axostyle (for details see Kirby, ’44). The present investigation dcmon- strates that the capitular portion of the axostyle does not arise within the blepharoplast complex but is anterior to and in juxtaposition to this region. Since the capitular portion of the axostyle extends beyond the blepharoplast complex, this part has been referred to by Samnels (’57) as the preblepharoplastic portion of the capitulum. From light and electron microscopic preparations of tritrichomonads it is

CYTOLOGY O F TRITRICHOMONAS 215

observed that tlie flagella do not emerge from the extreme tip of the organism, but slightly to one side. We are indeed re- ceptive to Samuels’ ( ’57) suggestion that “the preblepharoplastic portion of the capitulum prevents emergence (of the flagella) at the extreme anterior end of the cell.”

The functional significance of the axostyle is not clear; however, both it and the costa map function to help maintain the body shape of the organism. The axostyle may be, in part, contractile as suggested by Grass6 (’56) for the axostyle of Pyrsoaympha oertens.

With the resolution available to the light microscopists the exact relationship which the components of the parabasal body has with tlie blepharoplastic region could not be demonstrated. It can be seen from one of the electron micrographs presented that the parabasal filament originates iiidepeiident of the lamellar component. A number of investigators have reported on the parabasal body during division. I n these studies the authors were careful to point out that the bulk of the organelle, presumably the membrane and vesicular components is lost and only a small stub remains, probably portions of the parabasal filament (See Kirby, ’44). It is thought from the present observations that the parabasal filament is the only part of the parabasal complex directly associated tf-ith the blepharoplastic region.

Grass6 ( ’26) from light microscopic observations reported that the parabasal body typically consists of two parts, a chromophobic interior and a chromophilic exterior. A similar organization has been described by other workers. Anderson (’55) interpreted this organelle as belonging to the endoplasmic reticulum. Furthermore it appears, however, that the lamellar portion demonstrated by the electron microscope may be related to tlie chromophilic portion and the vesicular component to the chromophobic part of the Golgi material. This interpretation is borne out by the likeness in disposition, size and density of the components of this organelle to the ultrastructural organization of the Golgi complex described

216 EVERETT ANDERSON AND H. W. BEAMS

by electron microscopists for protozoa (Grass6 and Carrasso, '57; Sager and Palade, '57 and others), parazoa (Gatenby, Dalton and Felix, '55; Gatenby and Tahmisian, '58) and for metazoa (Dalton and Felix, '54; Burgos and Fawcett, '56; Beams, Tahmisian, Devine and Anderson, '56 ; Lacy, '57 and others.

The function of the parabasal body is unknown, however, it will suffice to point out that a few investigators mere of the opinion that it serves some role in the metabolism of the organism (Wenrich, '21). The small vesicles associated with the parabasal complex may synthesize material and move out to distribute it in the cytoplasm or perform some secretory process as has been suggested for the Golgi complex (see review by Bowen, '29).

SUMMARY

The submicroscopic structure of T'ritricho~nonns has been studied in thin sections by electron microscopy.

1. The flagella are composed of one central pair and nine pairs of pcripheral filaments anchored in basal bodies (kinetosomes).

2. The undulating membrane consists of three areas: (1) the recurrent flagellum, (2 ) the "accessory filament" which appears to be composed of granules occupying a zone between the filaments of the recurrent flagellum and the undulating membrane-proper and ( 3 ) a fibrous sheet-like component designated as the undulating membrane-proper. All of the components of the undulating membrane are enclosed within a single-layered membrane.

3. The costa appears to be a complex striated fiber system composed of an array of small dense bands alternating with broader ones of lower density. 4. The paracostal bodies (granules) display an internal

structure of vesicles and granules surrounded by a double limiting membrane envelope.


5. The axostyle appears to be a tubular organelle whose surface is composed of fine filaments oriented obliquely to its longitudinal axis.

6. The parabasal filament is seen to have an axial periodicity. Associated with the filament is the parabasal body displaying an ultrastructure similar to the Golgi complex of other cell types.

7. The nucleus is surrounded by a double membrane cn- velope interrupted by pores. The endoplasmic reticulum is seen encompassing the nucleus and is isomorphic with the basophilic area described by light microscopists.

8. The “chromatic ring” is seen to represent what appears to be elements of the endoplasrnic reticulum located a t the posterior end of the axostyle.

LITERATURE CITED

ALESEIEFF, A. 1924 Sur de le corps parabasal, l’axostyle et les mitochondria chez les flagellbs. Arch. Russ. Protist., 3: 129-152 (cited from Wenrich, D. H. 1944).

1955 The electron microscopy of Trichomonas m7wis. J. Proto- zool., 2: 114-124.

1957 Further observations on the fine structure of Trichornonas. Ibid., Supplement 27.

1956 Observations of Trypa~zo- soma eguiperdlcm. -1. Parasitol., 48: 11-16.

1956 Phase- contrast and electron microscope studies on the dietyosome and acrn- blast (Golgi bodics) i n the male germ cells of the cricket. J. Royal Micro. Soe., 76: 98-104.

BEIMS, I€. W., T. N. TAHMISIAN AND R. L. DEVINE 1957 Electron microscope observations on cilia from nephrostome epithcliuin of Lumbrirus t P r

restris. Anat. Rec., 127: 460. ROTEX, R. H. 1929 The cytology of glandular secrcltion. Quart. Rcv. Bin1 ,

4 : 299-394; 484-519. BURGOS, ?”I., AND D. W. FAWCETT An elertron microscope study of sper-

matid rliflerentiation in the toad, B r f o arenartrni Henscl, J. Riophys. Diochem. Cytol., 2: 223-240.

CUTTREY, D. W. 1954 Morphological variations in Tritrichomonas cur,q7r,rtn (Alexeieff) from amphibin. J. Norph., 94: 125-164.

D~I ,TOV, A. J., AND M. D. FELIX 1954 Cytologic and cytochemical charneteristic of the Golgi suhstnncc of epithelial cells of th r epididvnlis, in situ, in homogciiates and after isolation. Am. J. Snat. , 94: 171-208.

AFDERSON, E.

ANDERSOX, E., L. H. SAXE AND H. W. BEANS

REAMS, H. V., T. N. TAHNISISW, R. L. DEVIKE AND E. ANDERSON

1956

215 EVERETT AKDERSON AND H. W. BEAMS

FAWCETT, D. W.

FAWCETT, D. W., AND K. R. PORTER

GATENBY, J. E., A. J. DALTON AND M. n. FELIX

GATEXBY, J. R.. AND T. N. TAHYISIAN

1958 Specializations of the cell surface. In: Frontiers I n Cytology, (Sanford Palay, ed.). Yale Univ. Press, New Haven.

1954 A study of the fine structure of the ciliated epithelia. J. Morph., 9f: 221-281.

The contractile vacuole of parazoa and protozoa, and the Golgi apparatus. Nature, 176: 301.

1958 The contractile vacuoles and Golgi apparatus of EpJqdatio $zwzcutiEis : An electron niicroseope study. J. Royal Micro. Soc., (in press).

1926 Contribution a I’etnde drs flagelles parasites. Arch. Zool. Exp. et Gcn., 65: 345-602.

L ’ultrastructure de Pyrsonympha cer tms les flagelles et leur roaptation aree le corps, l’axostyle contractile, le para-axostyle, la cytoplasme.

GRASS^, P. P., AND AT. CAR~SSO Ultra-strurture of the Golgi apparatus in protozoa and metazoa (somatic and germinal cells). Nature,

KIRBY, H. Some observations on cytology 2nd niorphogenesis in flagellates. J. Morph., 7 5 : 361-421.

KIRBY, H., AND B. M. HONIGHERG Flagellates of the caecum of ground squirrels.

KOFOID, C. A, AND 0. SWEZY Mitosis and multiple fission in trichomonad flagcllates. Proc. Anier. Acad. Arts Sei., .51: 289-378.

LACY, D. 1957 The Golgi apparatus in neurons and epithelia cells of the common limpet Patrlln v ~ l g a l a . J. Biophys. Bioel~em. Cytol., 3 : 779-796.

LUDV~K, J. 1954 Studiunl bun8Eni: inorfologie Trzchomonas foe#us (Ricclmiiller’r elektronoym niikroskopen. Rcta Soc. 2001. Rohemoslovenirae, 18 :

PALADE, G. E. 1956 The endoplasmic reticulum. J. Biophys. Biochcm. Cytol.,

A small particulate component of the cytop1:tsm. In : Frontiers

1955

GRASS$, P. P.

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- Arch. Biol., 67 : 295-611.

1957

179: 31-33. 1944

1949 Univ. Calif. Pub. Zool., 5 3 : 31.5-366.

1915

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2 : 85-98. 7 958

I n Cytology, (Sanford Palay, 4.). Y a k Unir. Prcss, S e w Haven.

apparatus in Tricho?aymplza. J. hlorpli., 10Z: 199 -246.

Riophys. Acta, 76: 464470.

PITETX4, D. R., BKD c. N. SCHOOLEY 1958 The fine structurc O f the fl2gellor

POTTS, B. P. 1955 Electron microscope observations on trichocysts. Biochem.

RANDALL, J. T. Fine structure of some ciliate protozoa. Nature, 178: 9-14. 1957 Observations on contractile systemp, J. Cell. and Comp.

Physiol., 49 (mppl. 1 ) : 199-221). Structnre and development of the chloroplast

in Chlamydomonas 1. The normal grcen cell. J. Diophp% Diocbem.

RAMUELF, R. 1941 Tlic morphology and division of Trzchomonns augusta

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SAGER, R., AND a. E. PALADE 1956

Cytol., 3’: 463-488.

(Alexeieff ). Trans. Am. Micro. SOP., 60: 421- 440.

ism. J. Protozool., 4 : I f 0-118. 1957 Studies of Tritrichomonas bat? acakorcim 1. The trophir orgari


SCHMITT, 1'. 0. 1956 Xacromolecnlar interaction in patterns in biological systems. Proc. Am. Phil. Soc., 100: 476-486.

SCHYITT, F. O., C. E. HALL AND M. A. JAKUS 1942 Electron microscopic investigations of the structure of collagen. J. Ccll. and Comp. Physiol.,

The structure and divis~on of 2'1-ichonzonas ?nuriu IIart- man. J. Morph., 36: 119-155.

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PLATE 1

EXPLANATION OF FIGURES

2-5 Electron micrographs of the anterior end of the organism showing longitudinal (figs. 2, 3 and 5, af) and cross sections (figs. 4 and 5, a f ) of the anterior flagella. At cf in figures 2 and 3 may be noted granulcs within the basal bodies. The relationship of the costa ( c ) to the basal bodies of the flagella in the region of the blepharoplast may be seen (fig. 5, b) . At pbc (figs. 3 and 5 ) is the preblepharoplastic portion of the capitulum. All figures X 65,000.

220

CYTOLOGY OF TRITRICHOMONAS >,vinwrT OJI)EBWN AND 51. w. B I A M ~

PLATE 1

PTJATE 2

EXPLANATION OF FIGURE

6 A tangent ia l scction throngli the anterior end of the org;lnisin sbowinf tlir aiiterior flagclla (uf) and costa ( c ) originating in the region of thcl h1eph:iroplast (b). A t er is the rndoplasrriir reticulum arid pr, arc dense gi niiuleb aii;iiiged in clii rh . A t v arc lurgc rncuoles ant1 :i paracostal botl? at pc. In the uppcr left corner of the figure ji: a tangential section through the icearrmt fliigrllniii showing B loirgitudiiinl as \wll as n moss secational v iev of tlic internal donhle fileiiients cinhedilecl in granri1:rr matrix. X 65,000.

222

CYTOLOGY OF TRITKICHOblONAS WRRRTT ANUEILSOY AXD H. W. BEAM8

PL.4TE 3

EXPLANATION OF FIGURE

7 Tangential section through tlie anterior end of the organism. I n the upper right corner of the figure iiiay be observed cross sections of the anterior flagella ( a f ) as well as a longitudinal section of the recurrent flagellum ( r f ) . I n tlie basal body of the recurrent flageliuiii mag be seen granules (c f ) . At x is an unidentified body. The central (ca) and peripheral (pa) aspects of the axostyle as well as niitochonclria (in) are also illustrated in this section. To the left of the figure j s seen a portion of the nucleus limited hp a double membrane envelope. A nuclear pore is lalwled np and tlir endoplasniic rc~ticnlnin is sreii a t er. x 65,000.

224

CYTOLOGY OF TRITRICIIOJ1OS.iS EVERETT AXDEWOX .4SD IT. Vi. BEAMS

PLATE 3

8 aiicl 9 Rrctioii cnt lnngentinlly through the lnterul po’tion of the org:mism. I n t,he upper part, of tlic figurt: is see11 n sectioll through a fold of tllc undu1:tt- ing memhraw slmriiig the recurretit. flngellurii ( r f ) the I ‘ accessory filament” area (do) : I I I ~ the fibrous sheet-like corriponeiit, of the anilulating membrxne- proper (iiiiip). The curveil costa ( c ) mii hc sceii cottiposed of an array OP small deuse bands alternating with hroailer ones of l o v e r dcnsity (figs. 8 mil 9 ) . d collection of gr:iiiulcs ( g ) 311d ~ ~ a r a c 1 lioilics [ J C ) a r c i lh - strated in iigure 8. S o t c the rct.icular~lilic iirtworli nrouiicl the par;ieosl.al boaies. Figurc 8, X 65,000; figure 9, X 100,000.

CYTOLOGY OF TRITRICHOMOXAS RVRRBTT AXDERSON AND H. W. REAMS

PIATE 4

PLATE 5

EXPLb_UATlOh’ OF FICUKP.

10 A tangeutinl section through the orgauistri at a level posterior to t8hc nuelcus (nc). At, the top of thtr mirrograpli is t.he pnrnbasal body (pb) and t.hc associated vesicular eoniponent. (v). The axostylr (ax) is seen with its central (c:I) H I I ~ pcriplieral rspect.s (pa). JCndoplasmie rctieuluni (er), mitochondria (m) and iiiclusion body (ih) sire also shown. x 05,000.

PIAATE 6

EXPLASATIOX OF FIGURE

11 A ~eotioir through the posterior cnd of the organiRm diowing the mustylo (ax) tapering t o a point. Note tha fino Iilnments of the axoatylc oriented obliquelr to its longitudinal ax&. The central (ca) and pcripheeral (pa) aspects of the sxostyle are also Been. At wr are what appeaers tu be clemontn of tho ndo- pl1pamic reticulum. X 65,000.

CYTOLOGY O F TRITRTCHO&!ONSS EVERETT ANI>BRSON AN11 If. \T. BEAMS

PLATE i

ICSPIAh’hTION OF FIGURES

12, 13 arld 14 T:ingeiiti:il slioivirig tlie c lov relatioii~liip of tlie parahas:il body (1317) ivitlt the pn Glninent ( p f ) (figs. 12 and 14). Notice the di+ t inct doithlr i i i c ~ ~ ~ ~ t ~ r a i ~ c s composing tlic pn rnb~sa l hodj (pb) in figure 13. 111

figure 12 may IJC w c i i n 1ongitiidin:rI sectioii of the niitetior f lng~liuni, (:if) i?g i n the l ~ l ~ ~ ~ l i a i o p l n ~ t i c region ( 1 ~ ) . T h e peripheral ;~s:pcct (pa) -ostyle i s x c w c.oiiipowcl ot i i ini i> fin(. filanieiits. The iinelriis is 1;cheletl

lie (fig. 14). Figure 12, x 30,000; figures 13 a i d 14, x 65,000.

332

CYTOLOQY 01' TRITRICHOMONAS IVERETT ANDERSON AJD H. w. nmx8

PLATE 8

EXPLANATION O F FiCrTJRE

15 Section bliomiiig the nucleus ( n c ) and nuelcolus (nrl) . Surrounding tho nucleus are a miniher of eisternae of tlic eildoylasmic reticulum (er). The parabasal body (pb'l, para'rissal filament (pf) and peripheral aspect (pa) of the asostyle are also illustrated in this figure. X 30,000.

CPT<iI,OGP O F TRITRICTIONONA 8 EVERETT ANDERSON ANTI H. W, BI’AMS

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