Identification of nucleoli in the early branching protist Giardia duodenalis

Jiménez‐García, Luis Felipe; Zavala, Guadalupe; Chávez‐Munguía, Bibiana; Ramos‐Godínez, María del Pilar; López-Velázquez, Gabriel; Segura-Valdéz, María de Lourdes; Montañéz, Cecilia; Hehl, Adrian B.; Argüello-García, Raúl; Ortega‐Pierres, Guadalupe

doi:10.1016/j.ijpara.2008.04.012

Cited by 53 publications

(52 citation statements)

References 22 publications

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“…A fibrous and granular component characterizes an intranuclear region. Further analysis with transfection of the gene for the rRNA-pseudourydine synthase or fibrillarin also confirmed the presence of a nucleolar domain within the nuclei of G. lamblia [14].…”

Section: Discussionmentioning

confidence: 72%

“…The results mentioned for the presence of this nuclear organelle in such early divergent eukaryote organism [14], suggest that nucleoli may be considered a sine qua non structure for eukaryotes, further suggesting that the origin of nucleoli predates the origin of nuclei. In addition, the persistence of nucleolar material during cell division [17], may also indicate that nucleoli are active through cell division, an aspect that have to be explored.…”

Section: Discussionmentioning

confidence: 94%

“…Nucleolar material was observed as small fiber-granular areas of impregnation around 0.3 µm large [14] (Figure 1). Then, transmission electron microscopy (TEM) confirmed this result.…”

Section: Introductionmentioning

confidence: 99%

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The Nucleolus of Giardia lamblia

Jiménez‐García¹

2017

MOJAP

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The nucleolus is the major site of ribosome biogenesis in eukaryotes. Until recently, G. lamblia was considered the only eukaryote lacking nucleoli. Recently, light and electron microscopy cytochemical techniques have been used to demonstrate the presence of nucleoli in the interphase nucleus of G. lamblia. Here we review the work made during the last few years on the nucleolus of G. lamblia in interphase and cell division. This mini review indicates that nucleoli are present in G. lamblia interphase cell nuclei. Also, the persistence of nucleoli during cell division was documented more recently. Therefore, microscopical anatomy of G. lamblia should include the presence of authentic morphological nucleoli.

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Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 94%

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The Nucleolus of Giardia lamblia

Jiménez‐García¹

2017

MOJAP

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“…Further analysis with transfection of the gene for the rRNA-pseudourydine synthase or fibrillarin also confirmed the presence of a nucleolar domain within the nuclei of G. Lamblia. 14 The results mentioned for the presence of this nuclear organelle in such early divergent eukaryote organism, 14 suggest that nucleoli may be considered a sine qua non structure for eukaryotes, further suggesting that the origin of nucleoli predates the origin of nuclei. In addition, the persistence of nucleolar material during cell division, 17 may also indicate that nucleoli are active through cell division, an aspect that have to be explored.…”

Section: Discussionmentioning

confidence: 99%

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2017

MOJAP

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Abbreviations: AgNOR, silver staining for nucleolar organizer region; NOR, nucleolar organizer region; Rrna, ribosomal rna; TEM, transmission electron microscopy Introduction G. Lamblia, also known as G. Intestinalis or G. DSuodenalis, is a unicellular parasite infecting human large intestine and causing severe diarrhea.1-6 According to B. Ford, it was first observed by Antony van Leeuwenhoeck back in 1681, 7 as very small organisms, with a large body and a flattish belly with little paws and stir movements. G. Lamblia was later described taxonomically. 8G. Lamblia also belongs to early divergent lineages of eukaryotes as revealed by protein or nucleic acids sequence analysis, 9-11 although reduced processes also may have occurred.12 Studies on the cell biology of G. Lamblia have described several organelles as nuclei, mitosomes, flagella, several elements of cytoskeleton, but definite proof for the presence of Golgi apparatus or endoplasmic reticulum have not been documented.1-6 For a long time G. Lamblia was known as the only eukaryote lacking nucleoli. Since the detailed analysis searching for nucleoli failed to show the presence of nucleoli in Giardia even by using immunocytochemistry and in situ hybridization combined with the use of confocal microscopy, 13 it was asked whether classical cytochemical staining as silver staining for nucleolar organizer would produce better contrast than fluorescent techniques.The first evidence for the presence of nucleoli in G. Duodenalis, G. Intestinalis or G. Lamblia was obtained after using silver staining for nucleolar organizer regions (AgNOR) for light microscopy. Nucleolar material was observed as small fiber-granular areas of impregnation around 0.3µm large (Figure 1).14 Then, transmission electron microscopy (TEM) confirmed this result. In fact, standard technique for TEM produced results indicating an intranuclear electron dense material at the periphery of nuclei (Figure 2), that in addition was positive to silver staining for NOR, for RNA using the EDTA method for RNA, silver staining for NOR at the EM level followed by immunoelectron microscopy for fibrillarin and high resolution in situ hybridization for rRNA. Analysis of expression of transfected rRNA-pseudouridine synthase (CBF5) and confocal microscopy confirmed these results. Later on, additional light and electron microscopy techniques also revealed the presence of nucleoli (Figure 3). 15 Microscopical anatomy of G. Lamblia therefore, includes the presence of nucleoli. 4-6,16 Figure 1A) Bright field light microscopy after silver staining for nucleolar organizer region (AgNOR) staining in G. lamblia. B)Same image as A processed to enhance the silver stained material. Nucleolus is present as peripheral structures within both cell nuclei.More recently, it was reported further confirmation of the presence of nucleoli in G. Lamblia in interphase and also the persistence of this organelle through cell division, 17 therefore indicating that the process of nucleolar biogenesis does not include the formation of th...

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“…The trophozoite-to-cyst conversion process (encystation) of this parasite represents a primitive response to cellular stress. Likewise Giardia is a relatively simple eukaryote with reduced/cryptic structures such as mitosomes, Golgi-like apparatus and nucleolus (Tovar et al, 2003;Luján & Touz, 2003;Jiménez-García et al, 2008) coupled to a compact genome encoding a limited proteomic repertoire (Morrison et al, 2007). Nevertheless Giardia is considered as the most highly evolved and adaptedto-parasitism diplomonad on the basis of morphogenetic criteria (Keeling & Brugerolle, 2006).…”

Section: Introductionmentioning

confidence: 99%