Morphological Study of Taenia Taeniaeformis Scolex Under Scanning Electron

8/14/2019 Morphological Study of Taenia Taeniaeformis Scolex Under Scanning Electron

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ANNALS OF MICROSCOPY Vol 7, April 2007

80

Morphological Study OfTaenia taeniaeformis Scolex Under Scanning Electron

Microscopy Using Hexamethyldislazane

*Al-Jashamy K and Islam M. N.

1Department of Medical Microbiology and Parasitology,School of Medical Sciences, Universiti Sains Malaysia, Kubnag Kerian, Kelantan

2 Faculty of Health Sciences, Universiti Sains Malaysia, Kubnag Kerian, Kelantan

ABSTRACT

Taenia taeniaeformis commonly known as feline tapeworm, is recognized by lack of neck

and bell shape of posterior segments. This is known as the broad necked tapeworm of cats. The

neck is almost as broad as the scolex and segmentation begins immediately behind the scolex.

The scolex ofT. taeniaeformis is armed with a large double circlet of 30 to 40 hooks and four

clearly lateral suckers with lack of a neck. The very large hooks are arranged with double and

alternating circlet of hooks, and their size 0.36-0.44 mm for the anterior crown and 0.5-7 mm

for the posterior one. Therefore, it can be clearly differentiated T. taeniaeformis from all other

Taeniae species microscopically. The samples were dried by hexamethyldislazane (HMDS) before

examination under scanning electron microscopy

INTRODUCTION

Taenia taeniaeformis (Cestoda: Taeniidae) is a parasite characterized by a cosmopolitan

geographic distribution. The nal hosts are carnivores of the families Felidae, Canidae andMustelidae, including domestic cats and dogs (Nichol, et al., 98). Adults reach a maximum

length of about 60 cm and it occurs as adult tapeworms in the small intestine of carnivores as

denite hosts. The intermediate hosts of T. taeniaeformis are mouse, rat, cat, muskrat, squirrel,

rabbit, other rodent, bat and human. Cysticercus fasciolaris is a larval stage ofT. taeniaeformis

which, commonly found in a liver of intermediated host through contaminated water or feed

materials with infected cat feaces. There are some sporadic cases were reported in human from

Argentine, Czechoslovakia, Denmark and Taiwan (Nichol, et al., 98; Ekanayake, et al., 999).

The adult T. taeniaeformis can be subdivided into three body sections. The anterior region

in called the scolex, which is used to adhere to the intestine of the host species. In T. taeniaeformis,

the scolex is made up of four large suckers arranged around the sides with double circlet of hooks.Behind the scolex is the neck region, and nally the third region is the strobilus. The neck region is

fairly small, almost nonexistent, and it produces the proglottids (Iwaki, et al., 994). The HMDS

treatment seems very satisfactory for biomaterials as same as quality to CPD drying with a great

saving in time and without complex equipment (James, 984; Al-Salihi et al., 004). Therefore,

the objective of this study was to demonstrate the morphological structures ofT. taeniaeformis

scolex under scanning electron microscopy using HMDS

MATERIALS AND METHODS

Collecting specimens and scanning electron microscopy procedure

Scolexes of ten adult T. taeniaeformis parasites were collected from one cat which had

positive stool examination. In the rapid procedure, specimens were xed in 2.5% glutaraldehyde,


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dehydrated through a graded ethanol series, immersed in hexamethyldisilazane (HMDS) for 5

minutes 3 times, and air dried. Finally removed as much of the HDMS as possible and allow the

specimen to air-dry. The samples are then ready to mount and sputter coated with gold for scanning

electron microscopy.

RESULTS

The scolex is distinctly large, bearing four lateral suckers and a rostellum armed with

double and alternating rings of large and small hooks, hooks arranged in a circular pattern with a

large double circlet of 30 to 40 hooks, and their size 0.36-0.44 mm for the large anterior hooks and

0.5-7 mm for the small posterior one (Figure ). The scolex is a visible shape with four lateral

distinct suckers (Figure ). Top surface of the rostellum had micro-papillae (Figure 3). Specimens

prepared using the HMDS, and the results showed very clear structures and microstructures with

excellent surface details were observed. The HMDS treatment required about 5 minutes.

DISCUSSION

The rostellum armed with double and alternating rings of hooks, these hooks might have

roles to adhere the scloex of parasite within the gut epithelium of the host and later might due

to a damage of intestinal epithelium. Histopathology of stomach and small intestine revealed

gastroenteropathy associated with mucosal hyperplasia, and such observation has been recorded in

rats infected with larvae ofT. taeniaeformis (Abella, et al., 997), where there was proliferation of

submucosal glands and severe lymphoid follicular hyperplasia in duodenum. Immunouoresence

assay of brosarcoma in liver sections showed concurrence with spindle cell sarcoma (Bannasch,

et al., 980). The scolex often bears suckers which was sometimes able to absorb materials not

available to the other body segments, but absorption mainly occurs throughout the segments

(Nichol, et al., 98).

Used the HMDS as a dryer material showed that the morphological structures were very

clear and microstructures with excellent surface details were observed. The HMDS treatment

required about 5 minutes, whereas the critical point drying procedure required about .5 hours

(Al-Salihi, et al., 004). Specimens prepared by the HMDS treatment did not shrink or distort

upon air drying (Hochberg and Litvaitis, 000).

The results showed that HMDS is an effective alternative for preparing parasities for SEM

because it saves time and is cheaper compared to critical-point drying (CPD). The evaluation of

HMDS as an alternative treatment to CPD for preparing microscopic specimens for SEM and

as the primary dehydration solvent, was and compared with the results of earlier investigations

using CPD. The results of HMDS dehydration are similar to or better than CPD for resolution ofthese important taxonomic features. The only unfavorable result of HMDS dehydration was an

occasional coagulation of gold residue when the solvent had not fully evaporated before sputter-

coating (Bray et al., 993; Hochberg and Litvaitis, 000). This chemical hexamethyldisilazane is

readily available and cheap, no heating or cooling is needed for using HMDS. Some researchers

used as merely dehydrate specimens to 100% alcohol, and then do the two soaks of one-half hour

in pure HMDS (i.e. change the HMDS once). Other users agree with nding that HMDS is just as

effective or more effective than CPD for producing perfect specimens of various tissues (Nation,

983).

CONCLUSION

HMDS treatment and subsequent air drying provide good quality scanning electron


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micrographs that reveal both macro- and microstructures. The disadvantage of HMDS drying may

be a shrinkage and distortion similar to other drying agents. Ease of handling, low cost, and a high

rate of success are advantages that favor HMDS desiccation over other drying methods.

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the support provided by Electron Microscopy Unite /

Universiti Sains Malaysia / Penang

REFERENCES

Abella, Y., Oku, N., Nonaka, M. and M. Kamiya (1997). Role of host immune response in the

Scanning electron microscopy micrographs of Taenia taeniaeformis scolex showing: (Fig ), the scolex is distinctly

larger, bearing rostellum armed with double and alternating rings of large anterior hooks (AH) and small posterior

hooks (PH). Fig ), the scolex is a visible shape with four lateral distinct suckers (CU). Fig 3), the top surface of the

rostellum with micro-papillae (MP).


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occurrence of gastropathy in rats infected with larval Taenia taeniaeformis .J. Vet. Med. Sci.

59, pp10391043.

Al-Salihi K. A., Al-Jashamy K., Samsudin A.R., Afandi J. and Patchamuthu R. (2004). Comparative

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Bannasch, H., Zerban, E., Schmid and Franke W.W. (980). Liver tumors distinguished byimmunouorescence microcopy with antibodies to proteins of intermediate sized laments,

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Bray, DF., Bagu, J., Koegler, P., (993). Comparison of hexamethyldisilazane (HMDS). Peldri II,

and critical-point drying methods for scanning electron microscopy of biological specimens.

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Ekanayake, S., Warnasuriya, ND., Samarakoon, PS., Abewickrama, H., Kuruppuarachchi,

ND., Dissanaike, AS. (999). An unusual infection of a child in Sri Lanka with Taenia

taeniaeformis of the cat. Ann Trop med prasito. 93, pp. 869-73.

Hochberg, R and Litvaitis MK. (2000). Hexamethyldisilazane for scanning electron microscopy of

Gastrotricha. Biotech Histochem. 75, pp.4-4.Iwaki, T., Nonaka, N., Okamoto, M., Oku, Y and Kamiya M. (994). Developmental and

morphological characteristics ofTaenia taeniaeformis Clethrionomys rufocanus bedfordiae

and Rattus norvegicus from different geographical locations. J Parasitol. 80, pp. 461-7.

James, L. N. (984). A new methods using hexamethyldisilazane for preparation of soft insect

tissue for scanning electron microscopy. Florida Agri. Exper. Station. J. 58 pp 347-35

Nation JL. (983). A new method using hexamethyldisilazane for preparation of soft insect tissues

for scanning electron microscopy. Stain Technol. 58 (6):347-5.

Nichol S., Ball S. J and Snow, K. R. (1981). Prevalence of intestinal parasites in feral cats in some

urban areas of England Vet. Parasito. 9, pp. 07-0.

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Morphological Study of Taenia Taeniaeformis Scolex Under Scanning Electron