Microtubule Disruption does not Impair Learning in the Unicellular Organism Paramecium: Implications for Information Processing in Microtubules

Information processing in microtubules is an open question that has not been properly addressed yet. It was suggested that microtubules could store and process information in the nervous system or even support consciousness. The unicellular organism, Paramecium caudatum, that has a microtubular structure but does not have a neuron or neural network, shows intelligent behaviors such as associative learning. This may suggest that the microtubules are involved in intelligent behavior, information storage or information processing in paramecium. To test this hypothesis, we have utilized a paramecium learning task in which the organism associates brightness in its swimming medium with attractive cathodal shocks to study the role of microtubules in paramecium learning. We disrupted the microtubular dynamics in paramecium using an antimicrotubular agent (parbendazole) to see if microtubules are an integral part of information storage and processing in paramecium. We observed that while a partial allosteric modulator of GABA (midazolam) could disrupt the learning process in paramecium, the antimicrotubular agent could not interfere with the learning in paramecium. Therefore, our results suggest that microtubules are probably not vital for the learning behavior in P. caudatum. Consequently, our results call for a further revisitation of the microtubular information processing hypothesis.

Analisis P/b Rasio Foraminifera di Perairan Delta Wulan, Demak, Jawa Tengah

Foraminifera merupakan organisme uniseluler yang dapat berperan sebagai indikator lingkungan serta dapat menentukan lingkungan pengendapan. Cara hidup foraminifera dibagi menjadi dua yaitu foraminifera planktonik (melayang) dan foraminifera bentonik (menambat). Peran foraminifera sebagai organisme indikator ideal karena memiliki siklus hidup relatif singkat sehingga memfasilitasi peristiwa rekaman episodik (Haunold et al., 1997). Saat ini foraminifera banyak hidup di perairan laut dangkal dan laut dalam seperti di Delta Wulan, Demak. Litologi penyusun Delta Wulan ini masih berupa endapan sedimen yang dapat diketahui bahwa delta ini berumur Kuarter. Sehingga, persentase P/b Rasio dapat digunakan untuk menganalisis lingkungan pengendapan (Grimsdale dan Morkhoven, 1955). Tujuan dari penelitian ini adalah untuk menentukan komposisi foraminifera dan P/b rasio sebagai indikator lingkungan pengendapan. Penelitian ini dilaksanakan pada bulan Januari dan Maret 2019 di perairan Delta Wulan, Demak. Metode yang digunakan dalam penelitian ini adalah metode survei eksploratif. Pengambilan sampel dilakukan secara purposive sampling dengan menetapkan 12 titik penelitian. Berdasarkan hasil penelitian ditemukan 24 genus foraminifera yang dikelompokkan menjadi 4 kelas, yaitu Globothalamea, Fusulinata, Tubothalamea dan Nodosariata. Nilai kelimpahan untuk foraminifera planktonik berkisar 57-8000 ind/m2sedangkan foraminifera bentonik berkisar 29-314 ind/m2. Nilai P/b Rasio berkisar antara 86 – 93% dengan kategori batimertri batial atas.Foraminifera is an unicellular organism that can act as an environmental indicator and can determine the depositional environment. The way of life of foraminifera is divided into two namely planktonic foraminifera (floating) and bentonic foraminifera (tethering). The role of foraminifera as an ideal indicator organism because it has a relatively short life cycle thus facilitating episodic recording events (Haunold et al., 1997). At present many foraminifera live in shallow and deep sea waters such as the Wulan Delta, Demak. This Wulan Delta lithology is still in the form of sediment deposits which can be seen that this delta is Quaternary age. Thus, the percentage P/b ratio can be used to analyze the depositional environment (Grimsdale and Morkhoven, 1955). The purpose of this research is to determine the composition of foraminifera and P/b ratio as indicators of depositional environment. This research was conducted in January and March 2019 in the waters of Delta Wulan, Demak. The method used in this research is explorative survey method. Sample was collected by using purposive sampling and deciding 12 research sites. Based on the results of the study found 24 genus foraminifera which are grouped into 4 classes, namely Globothalamea, Fusulinata, Tubothalamea and Nodosariata. The abundance value for planktonic foraminifera ranges from 57-8000 ind/m2 while the bentonic foraminifera ranges from 29-314 ind/m2. The value of P/b Ratio range from 86 - 93% with the upper batial bathymetry category.

Current understandings of the relationship between extracellular vesicles and cilia

Mammalian cells have a tiny hair-like protrusion on their surface called a primary cilium. Primary cilia are thought to be the antennae for the cells, receiving signals from the environment. In some studies, extracellular vesicles (EVs) were found attached to the surface of the primary cilium. An idea for the phenomenon is that the primary cilium is the receptor for receiving the EVs. Meanwhile, a unicellular organism, Chlamydomonas, which has two long cilia, usually called flagella, release EVs termed ectosomes from the surface of the flagella. Accumulating evidence suggests that the primary cilium also functions as the ‘emitter’ of EVs. Physiological and pathological impacts are also elucidated for the release of EVs from primary cilia. However, the roles of released cilia-derived EVs remain to be clarified. This review introduces the historical background of the relationship between EVs and cilia, and recent progresses in the research field.

Whole Organism Model to Study Molecular Mechanisms of Differentiation and Dedifferentiation

Cancer recurrence has remained a significant challenge, despite advances in therapeutic approaches. In part, this is due to our incomplete understanding of the biology of cancer stem cells and the underlying molecular mechanisms. The phenomenon of differentiation and dedifferentiation (phenotypic switching) is not only unique to stem cells but it is also observed in several other organisms, as well as evolutionary-related microbes. Here, we propose the use of a primitive eukaryotic unicellular organism, Acanthamoeba castellanii, as a model to study the molecular mechanisms of cellular differentiation and dedifferentiation.

Synchronisation of yeast cell cycle through quorum sensing coupling

The cell cycle is present in all cells of all species and it is of fundamental importance in coordinating all the steps required for cell replication, including growth, DNA replication and cell division. Budding yeast is an unicellular organism characterised by a mother cell that buds to generate a daughter cell at each cell cycle. Each cell in a population buds at a different time. Despite its importance in biological applications, such as unravelling cell-cycle machinery mechanisms and production of valuable bioproducts, at present no yeast strain is capable of budding synchronously. To overcome this problem, we used control theory to propose a strategy to modify the yeast cell to endow it with the ability to synchronise its cell cycle across the population. Our strategy relies on a quorum sensing molecule diffusing freely in and out of the cell. The quorum sensing molecule is produced only during a specific phase of the cell cycle and couples the cell-cycle across the cell population. Here we model the proposed strategy with ordinary differential equations and numerically simulate it to demonstrate the feasibility of such an approach.

The N-glycans of Chlorella sorokiniana and a related strain contain arabinose but have strikingly different structures

The many emerging applications of microalgae such as Chlorella also instigate interest in their ability to conduct protein modifications such as N-glycosylation. Chlorella vulgaris has recently been shown to equip its proteins with highly O-methylated oligomannosidic N-glycans. Two other frequently occurring species names are Chlorella sorokiniana and Chlorella pyrenoidosa—even though the latter is taxonomically ill defined. We analyzed by mass spectrometry and nuclear magnetic resonance spectroscopy the N-glycans of type culture collection strains of C. sorokiniana and of a commercial product labeled C. pyrenoidosa. Both samples contained arabinose, which has hitherto not been found in N-glycans. Apart from this only commonality, the structures differed fundamentally from each other and from that of N-glycans of land plants. Despite these differences, the two algae lines exhibited considerable homology in their ITS1-5.8S-ITS2 rDNA sequences. These drastic differences of N-glycan structures between species belonging to the very same genus provoke questions as to the biological function on a unicellular organism.

When Unity Is Strength: The Strategies Used by Chlamydomonas to Survive Environmental Stresses

The unicellular green alga Chlamydomonas reinhardtii is a valuable model system to study a wide spectrum of scientific fields, including responses to environmental conditions. Most studies are performed under optimal growth conditions or under mild stress. However, when environmental conditions become harsher, the behavior of this unicellular alga is less well known. In this review we will show that despite being a unicellular organism, Chlamydomonas can survive very severe environmental conditions. To do so, and depending on the intensity of the stress, the strategies used by Chlamydomonas can range from acclimation to the formation of multicellular structures, or involve programmed cell death.