Plasmalemmasomes and Lomasomes in Candida Albicans, Article Critique Example

Introduction

Rajasingham and Cawson (1984) published a study to refute earlier findings which stated that the fungus, Candida albicans, could only be found in either lomasomes, or in plasmalemmasomes. Lomasomes are tubular membranous wall bodies found between the plasma membrane and the cell wall of Polystictus versicolor (Stevens, 1912). The latter is one of the most common wood-rotting saprophytes. Earlier studies regarded plasmalemmasomes as structures produced from plasmalemma through the process of in-folding  (Rajasingham & Cawson, 1984). However, Rajasingham and Cawson (1984) found that Candida albicans possesses properties of both plasmalemmasomes and lomasomes, which were historically only thought to be present in eumycetes.

The Experiment

The authors’ claim derived from a study during which they collected scrapings from the oral legions of human patients who have been diagnosed with mucosal candidal infections (p. 21). The scrapings were then fixed in osmium tetroxide and buffered with veronal acetate at zero degrees Celsius and at a pH level of 7.4. The scrapings were then dehydrated in a series of ethyl alcohol solutions before it was cleared in propolyne oxide and embedded in Taab resin. After this step, the researchers polymerized the scrapings for two days at 60 degrees Celsius. After two days, very thin slices were cut at 60 and 90 degree nanometers and mounted on clean copper grids and stained in alcoholic uranyl acetate and alkaline lead citrate. The scrapings were finally examined through a Joel 100Belectron microscope. The examination proved the scrapings to consist primarily of candidal hyphae and human epithelial cells (p. 21).

The Results

The authors argue that the examination of the sectional fragments of the scrapings showed the various stages of development for plasmalemmasomes and lomasomes. This examination also proved that plasmalemmasomes, although less obviously so than lomasomes, did in fact embed itself in the cell’s wall material. These findings, therefore, would suggest that plasmalemmasomes change into lomasomes during cell wall synthesis (Marchant & Moore, 1973). As such, the endoplasmic reticulum and lomasomes are considered to be the practical equal to the Golgi apparatus in Candida albicans.

Design and Interpretation Errors

Although the researchers conducted a meticulous experiment, which, under normal circumstances would have rendered very accurate results, one issue became evident upon further investigation. The premise of the experiment is based on fungal infections and the properties that plasmalemmasomes and lomasomes adopt once they become active and interact with other surfaces; most specifically cell walls. However, the results of the experiment could have been compromised due to the fact that different fungal infections present different characteristics. Although the authors identified the infection as a mucosal candidal infection, it is important to note that that particular infection has many derivatives, which could have rendered different results, had a particular derivative been identified. In other words, interactions between Candida albicans and epithelial surfaces will differ between various types of Candida albicans. This will therefore change subsequent microbial-mucosal interactions (Moyes & Naglik, 2011).

The Candida species is considered the most common of human fungal pathogens. As such, it is the primary causative agent of vaginal, gastrointestinal, and oral candidiasis (p. 2). In fact, vaginal candidiasis affects an estimated 30 million women annually. In addition, nearly 90 percent of all AIDS patients and nearly 50 percent of all HIV patients suffer from oral candidiasis. The result of these statistics is that Candida infections are the most common oral manifestation of HIV contagions. This fungus is also responsible for the development of mucosal diseases in geriatric populations. Furthermore, infections caused by the Candida species result in the third most common hospital-acquired bloodstream infection (Moyes & Naglik, 2011). It is clear, therefore, that the Candida fungi is a predominant health concern and has a severe impact on the wellbeing of a large portion of the global population. It is therefore vital that scientists and researchers comprehend the mechanisms involved in host-Candida interactions because the majority of Candida infections take place at mucosal surfaces, despite the fact that they present far more complex qualities on a deeper level (Calderone & Fonzi, 2001).

These deeper qualities will, by definition, mean that it will present different outcomes when coming into contact with other surfaces. This is true because each derivative of the Candida species is comprised of a variety of qualities. That is why each derivative can cause a different disease. The human micro biome has different interactions with its host; therefore, a specialized set of interactions exist between the host organism, the pathogenic microbes, and the residential micro biota (Marchant & Moore, 1973). The variation in interaction result in either some form of mutualism in the case of the resident, or in ruptures in the epithelial barrier; which typically either results in disease pathology, or immune activation. In other words, the host discriminates between pathogenic and commensal microbes. The reasons for this occurrence are not well understood, and little evidence exists to offer a conclusion.

What is known, however, is that the Candida albicans fungus is considered an opportunistic microbe, which goes through various pathogenic and commensal states. In addition, the fungus typically exists as a commensal organism in more than half of the human population (Moyes & Naglik, 2011). This fungus does not typically cause pathology; however, changes in the environment, such as altered local immune defenses, can cause it to become pathogenic. It is at this point that the fungi will cause a mucosal disease.

The Solution

The researchers neglected to identify the causes for the pathogenic qualities found in the scrapings of their study subjects. This means that they simply assumed the basic qualities of the Candida fungus to render their study results. However, it could very well be possible that the results will only be true for a specific Candida variation. For instance, if the subjects were infected with oral candidiasis, the results of this study may be based solely on that fact. However, if the subjects were infected with gastrointestinal candidiasis, the result would be different. Also, the researchers did not state how many of the scrapings had the same results. In other words, they did not state that 100 percent of the scrapings showed that plasmalemmasomes, although less obviously so than lomasomes, did in fact embed itself in the cell’s wall material. This means that some segments of the scraping samples may have rendered different results, which could indicate a different variation of the Candida fungus. A similar study should specify between the types of fungal infection that the study participants suffered from, so as to deliver more accurate and conclusive results.

References

Calderone, R. A., & Fonzi, W. (2001). Virulence factors of Candida albicans. Trends in Microbiology, 9(7), 327–335.

Marchant, R., & Moore, R. T. (1973). Lomasomes and plasmalemmasomes in fungi. Protoplasma, 76(2), 235-247.

Moyes, D. L., & Naglik, J. R. (2011). Mucosal Immunity and Candida albicans Infection. Clinical and Developmental Immunology, 2011, 1-9.

Rajasingham, K., & Cawson, R. (1984). Plasmalemmasomes and lomasomes in Candida albicans. Cytobios, 40(157), 21-25.

Stevens, N. E. (1912). Polystictus Versicolor as a Wound Parasite of Catalpa. Mycologia, 5(4), 263-270.