Unicellular Microorganisms Research Articles

Phycoremediation as a Strategy for the Recovery of Marsh and Wetland with Potential in Colombia

Colombia is the country with the sixth highest amount of water reserves in the world, and 25% of its territory is covered by wetlands. However, approximately 50% of the country’s water is estimated to exhibit some type of contamination related to anthropic activities. An alternative for the treatment and the recovery of its bodies of water is the use of microalgae, unicellular, and mixotrophic microorganisms, as these bioreactors are highly adaptable to the environment, and their maintenance costs are minimal, because they feed on almost any substrate. In fact, different countries have already reported using microalgae as bioremediators for bodies of water. The use of these microphytes is efficient because they metabolize, degrade, or bioaccumulate heavy metals, pesticides, emerging pollutants, and antibiotics. In general, strategies relying on microalgae to eliminate pollutants are very similar to one another. For example, the first stage often includes a process of bioadsorption, consumption, degradation, and accumulation, wherein the microalgae use molecules generated from their own cellular metabolism. Some pilot studies focusing on the phycoremediation of marshes and other bodies of water have already been conducted in Colombia; however, more studies on process optimization, effectively leveraging the biodiversity of the existing microalgae, and better adapting microalgae to the region are still required.

ISOLATION OF MICROALGAE FROM ANTARCTIC SOIL

Microalgae are unicellular photosynthetic microorganisms which are able to survive in extreme environmental conditions, specifically low temperature, high evaporation rates as well as low water availability. Polar microalgae from the Antarctic region have received attention from researchers due to their special adaptations for surviving in extremely cold environments and being isolated from various types of samples. Four Antarctic soil samples were used on this study namely-Sample A, Sample B, S18 and S30. All soil samples were subjected to serial dilution and spread on BBM followed by 3 weeks incubation at 25oC with periodic light. Only soil sample S30 showed positive microalgae growth after additional 3 weeks incubation period. Consequently, soil sample S30 was proceeded to isolation of microalgae using BBM, 3N- BBM+V, JM and MWC media. Observable growth of green microalgae could only be obtained using 3N-BBM+V and JM media. Moreover, 3N-BBM+V medium successfully produced the highest number of microalgae colonies recovered from Antarctic soil sample. Isolation of microalgae from Antarctic provides resources for various industrial and commercial applications.

Gut Microbiome Profiles in Colonizations with the Enteric Protozoa Blastocystis in Korean Populations.

The influence of unicellular eukaryotic microorganisms on human gut health and disease is largely unexplored. Blastocystis species commonly colonize the gut, but their clinical significance and ecological role are unclear. We evaluated the effect of Blastocystis colonization on the fecal microbiota of Koreans. In total, 39 Blastocystis-positive and -negative fecal samples were analyzed. The fecal microbiome was assessed by targeting the V3–V4 region of the bacterial 16S ribosomal gene. Bacterial diversity was greater in the Blastocystis-positive than in the Blastocystis-negative group. The bacterial community structure and phylogenetic diversity differed according to the presence of Blastocystis. The mean proportions of Faecalibacterium species and Ruminococcaceae were larger in the Blastocystis-positive group, and that of Enterococcus species was larger in the Blastocystis-negative group. Linear discriminant analysis showed that Faecalibacterium, Prevotella 9, Ruminococcaceae UCG-002, Muribaculaceae, Rikenellaceae, Acidaminococcaceae, Phascolarctobacterium, and Ruminococcaceae UCG-005 were highly enriched in the Blastocystis-positive group, whereas Enterococcus hirae, Enterococcus faecalis, Enterococcus durans, Enterococcaceae, Lactobacillales, and Bacilli were highly abundant in the Blastocystis-negative group. Overall, our results enlighten the notion that Blastocystis colonization is associated with a healthy gut microbiota.

Bioelectricity generation from live marine photosynthetic macroalgae

The conversion of solar energy into electrical current by photosynthetic organisms has the potential to produce clean energy. Bio-photoelectrochemical cells (BPECs) utilizing unicellular photosynthetic microorganisms have been studied, however similar harvesting of electrons from more evolved intact photosynthetic organisms has not been previously reported. In this study, we describe for the first time BPECs containing intact live marine macroalgae (seaweeds) in natural seawater or saline buffer. The BPECs produce electrical currents of >50 mA/cm2, from both light-dependent (photosynthesis) and light-independent processes. These values are significantly greater than the current densities that have been reported for single-cell microorganisms. The photocurrent is inhibited by the Photosystem II inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, indicating that the source of light-driven electrons is from photosynthetic water oxidation. The current is mediated to the external anode via NADPH and possibly other reduced molecules. We show that intact macroalgae cultures can be used in large-scale BPECs containing seawater, to produce bias-free photocurrents, paving the way for the future development of low-cost energy solar energy conversion technologies using BPECs.

Phytochemicals: Their role and mechanism in suppressing plant pathogenic bacteria

Bacteria are unicellular prokaryotic micro-organisms which may be beneficial or harmful to plants. Earlier the infections caused by plant pathogenic bacteria were controlled by applying antibiotics and synthetic chemicals. But over-use of these antibiotics has resulted in evolving of antibiotic-resistant bacterial strains. Thus, it is the need of hour to explore alternative ways to target the bacterial virulence factors. Phytochemicals are extract from plants capable of inhibiting the growth of micro-organisms through various mechanisms, some which already been explained, while some others yet to be. In this review article, we are discussing about various phytochemicals, their source plant, their properties and composition, mode of actions, the bacterial phytopathogens on which they are effective, also some new perspectives of how they are gaining importance in the world of organic pesticides.

Paramecium, a model organism to study ciliogenesis and ciliopathies

The cilium is a cell extension forming a distinct compartment of eukaryotic cell body with a complex and dynamic structure. This structure is highly conserved across species and ensures various functions as sensory and motility. In humans, ciliary dysfunction results in diseases (ciliopathies) that can affect all organs. Thanks to its complex ciliary structure, the unicellular and ciliated microorganism, Paramecium, constitutes a model of choice not only to study the structure, assembly and function of cilia but also to validate the specific role of mutations of genes linked to the ciliopathies.

Testate amoebae from two low-lying tropical islets of Tuvalu, South Pacific

Testate amoebae are a polyphyletic group of ubiquitous unicellular eukaryotic micro-organisms. They occur in high abundances in freshwater and terrestrial habitats, where they play an important role in biogeochemical and ecological processes. Terrestrial amoeba data from small tropical islands are rarely available despite the fact that they are interesting for investigations on global change induced sea level rise, biodiversity and biogeography. Based on a previously published paper on the impact of increased salinity to testate amoebae, the aim of this study is to present data on amoebal biodiversity from two remote, low-lying tropical islets of Tuvalu (South Pacific). In total 47 species and subspecific taxa of testate amoebae were recorded. These findings are based on 21 soil samples from 7 terrestrial habitats examined microscopically. Most species found were relatively small (< 100 μm) and considered as cosmopolitan. Non-metric multidimensional scaling ordination (NMDS) separated the samples by habitat structure and flooding regime rather than islet origin. Despite the apparently remote character of the study sites, human influence on distribution and biogeography of testate amoebae cannot be excluded.

Identification of Bacteria in Kawista Leaves (Limonia acidissima L.)

Background: Bacteria are unicellular prokaryotic microorganisms which are abundant in nature. This study aims to isolate and identify bacteria present in the leaves of Kawista (Limonia acidissima L.). Method: The identification process was carried out in a microbiology analyzer with the help of the BD Phonix M50 identification tool. The study was conducted at the West Nusa Tenggara Province Testing and Calibration Laboratory for Health, using kawista (Limonia acidissima L.) leaves obtained from West Sumbawa Regency. Results: The results showed eight bacterial isolates were found including Bacillus sp, Bacillus megaterium, Staphylococcus sp, Staphylococcus epidermidis, Staphylococcus capitis, Streptococcus oralis, Leuconostoc mesenteroides spp. mesenteroides, and Shewanella putrefaciens. Conclusion: Diversity of types of bacteria can be studied through the process of identification. This study aims to isolate and identify bacteria found in kawista leaves. The identification method is carried out in a microbiology analyzer with the help of the BD Phonix M50 identification tool. Bacteria found on the leaves of kawista (Limonia acidissima L.) consist of a group of endophytic bacteria, lactic acid bacteria, metal reducing bacteria, and pathogenic bacteria.

Solid-state culture of Azospirillum brasilense: a reliable technology for biofertilizer production from laboratory to pilot scale.

A biofertilizer of Azospirillum brasilense was produced in solid-state culture (SSC) from laboratory to pilot scale. Similar operation conditions (continuous aeration and mild intermittent mixing) and two dimensionless numbers with similar L/D ratio and a similar working volume were applied to reach a scale-up factor of 75. An innovative bioreactor with rotating helical ribbons (15kg wet matter) was used at pilot scale. A mathematical model was proposed and validated to evaluate the respirometry trends at laboratory and pilot scale exhibiting similar behavior. The cell viability was (1.3 ± 0.4) × 109 and (1.3 ± 0.3) × 109 colony-forming units per gram of initial dry mass at laboratory and pilot scale, at 36 and 43h, respectively. A. brasilense maintains its viability twelve months of storage at 4 and 30°C. This is the first report of A. brasilense being cultivated in SSC under controlled conditions. SSC processes involving unicellular microorganisms with tolerance to agitation are a promising technology to produce biofertilizers.

Evolution of Photobioreactors: A Review based on Microalgal Perspective

Energy is indispensable for bringing competence, resilience, and comfort for the ever-advancing human lifestyle. Therefore, to satisfy the growing energy requirement researchers are trying to delve in exploring sustainable and renewable energy sources that will contribute to the reduction of carbon footprint and ultimately help to check the issue of global warming caused by the increased emission of CO2, due to the excessive usage of non-renewable and exhaustive fossil fuels. Microalgae are having the potential which can be exploited to produce biofuels (substitute for fossil fuels) and other value-added compounds. Microalgae is a form of unicellular photoautotrophic microorganism which can attain higher rate of proliferation. Microalgae is having merits over other terrestrial crops and fossil fuels as they have higher productivity of oil per hectare of land. Various other advantages of microalgae include their tolerance in different types of environment because of their ubiquitous nature (in terms of pH, salinity, and temperature). Furthermore, they can be cultivated in nonarable land and wastewater which will resolve the food-fuel duel and problem of freshwater usage, therefore leading towards environmental sustainability. The main factors governing the growth and cultivation of microalgae are light, CO2/air, nutrients, process parameters (pH, temperature, growth medium etc) and most importantly the type of system used for cultivation. The systems usually employed for the cultivation of microalgae are open system (open ponds, raceway ponds, scrubbers), closed system also commonly known as photobioreactors (flat plate and tubular photobioreactors) and hybrid system in which separation of biomass growth and lipid accumulation is achieved in two stages. All the systems have some merits and demerits but photobioreactors are widely accepted and used because they are having an upper hand over open system because of the optimised control of the growth conditions, contamination evasion and efficient productivity of microalgal biomass. This review will provide an insight to different parameters which govern the growth of microalgae and various types of photobioreactors with their advantages and disadvantages. This study will help in the optimized selection of the photobioreactors for a particular species of microalgae because despite the continuous and intensive research going on the cultivation systems it is a challenge for the researchers to achieve a suitable and economically viable system.

Assessment of the Prevalence of Malaria and Typhoid Fever among Apparently Healthy Undergraduates

Malaria is a mosquito-borne infectious disease of humans and other animals caused by parasitic protozoans (a type of unicellular microorganism) of the genus Plasmodium. Commonly, the disease is transmitted via a bite from an infected female Anopheles mosquito, which introduces the organisms from its saliva into a person’s circulatory system. In the blood, the protists travel to the liver to mature and reproduce. Malaria causes symptoms that typically include fever and headache which in severe cases can progress to coma or death. The disease is widespread in tropical and subtropical regions in a broadband around the equator, including much of Sub-Saharan Africa, Asia, and the Americans Five species of Plasmodium can infect and be transmitted by humans. The vast majority of deaths are caused by Plasmodium falciparum and Plasmodium vivax, while Plasmodium ovale and Plasmodium malariae cause a generally milder form of malaria that is rarely fatal. The result showed that prevalence of typhoid fever in both male and female are 9 (%) and 21 (21%) respectively. The distribution of this result was statistically significant (p&lt;0.05; X2=4.745). The result showed that prevalence of typhoid fever in both male and female are 6 (6%) and 4 (4%) respectively. The distribution of this result was not statistically significant (p&gt;0.05; X2=0.105). The result showed that prevalence of the co-infection in both male and female are 3 (3%) and 2 (2%) respectively. The distribution of this result was not statistically significant (p&gt;0.05; X2=0.205). The result showed that co-infection was negatively correlated with typhoid fever in both male (r=-0.055) and female (r=-0.074) subjects. Also co infection was negatively correlated with malaria for male subjects (r=-0.044) while it is positively correlated with the female subjects (r=0.335). Similarly typhoid fever was negatively correlated with malaria in both male (r=-0.079) and females (r=-0.105) subjects. Conclusively, the results in this study showed that the prevalence of malaria and typhoid co-infections are low which means the no association was found between malaria and typhoid fever infections within the study area. Hence one cannot actually say that malaria may predispose to typhoid fever. Also cross reacting antigens are widely distributed in the microbial world and since there will always be repeated exposures to salmonella species in endemic regions, increased efforts should be made to find a better, more rapid, sensitive and specific clinical and cultural methods.

Single-cell Raman micro-spectroscopy for tracking of carotenoids in cyanobacteria exposed to Mn and Zn doped ferrite nanoparticles

Ferrite nanoparticles are increasingly produced and exploited as adsorbents for environmental pollutants. However, their impact on the aquatic microbiota such as cyanobacteria, are not yet investigated. Targeting the environmental monitoring context, in this paper we explored for the first time if any change in the carotenoid signal from cyanobacteria Coelomoron pussilum (AICB 1012) exposed to non-lethal doses of Mn and Zn doped ferrite nanoparticles (NPs) can be associated with the nano-aggression on single-cell level, using micro-Raman spectroscopy. UV–Vis absorption spectroscopy of the bulk culture and single-cell Raman microscopy showed that the carotenoid signal increases relative to the chlorophyll contribution upon exposure of the cells to the Mn-ferrite NPs throughout the 7 days of the experiment. The red-shift and broadening of the strongest carotenoid Raman band arising from (CC) stretching modes indicates the change of carotenoid profile towards increased amount of β-carotene in answer to the NPs stress. The increase of this band intensity relative to the fluorescence background was also observed in Zn-ferrite NPs treatment. Using a simplified and rapid sample preparation procedure, electron microscopy in both transmission and scanning modes, showed greater coverage of the cells by the stable colloidal AgNPs than by the magnetic ferrite NPs. The latter mostly clumped together rather than adhering to the cells. The combined single-cell micro-Raman tracking of physiological response of the unicellular photosynthetic microorganisms coupled with electron microscopy approach to visualise cell-NPs interaction and the extracellular polymeric substance secretion holds the promise for rapid assessment of the NPs-induced environmental stress acting on the unicellular organisms.

Unique Cl- pump rhodopsin with close similarity to H+ pump rhodopsin.

Microbial rhodopsin is a ubiquitous membrane protein in unicellular microorganisms. Similar to animal rhodopsin, this protein consists of seven transmembrane helices and the chromophore retinal. However, unlike animal rhodopsin, microbial rhodopsin acts as not only a photosignal receptor but also a light-activated ion transporter and light-switchable enzyme. In this article, the third Cl– pump microbial rhodopsin will be introduced. The physiological importance of Cl– pumps has not been clarified. Despite this, their mechanisms, especially that of the first Cl– pump halorhodopsin (HR), have been studied to characterize them as model proteins for membrane anion transporters. The third Cl– pump defines a phylogenetic cluster distinct from other microbial rhodopsins. However, this Cl– pump conserves characteristic residues for not only the Cl– pump HR but also the H+ pump bacteriorhodopsin (BR). Reflecting close similarity to BR, the third Cl– pump begins to pump H+ outwardly after single amino acid replacement. This mutation activates several residues that have no roles in the original Cl– pump function but act as important H+ relay residues in the H+ pump mutant. Thus, the third Cl– pump might be the model protein for functional differentiation because this rhodopsin seems to be the Cl– pump occurring immediately after functional differentiation from the BR-type H+ pump.

Acoustic synthesis of feed proteins under conditions of a complex ultrasonic field

Liquid waste of food industry enterprises contains various valuable organic substances of natural origin, which can be rationally used to obtain feed proteins. The problem of using valuable substances from food waste solves the problem of using biotechnological methods in order to use methods of accumulating biomass, enzymes, vitamins, etc. The biomass of unicellular microorganisms formed in the process of cultivation can be a raw material for obtaining feed additives and other biologically active substances.

Penapisan Enzim Invertase dari Khamir Asal Nektar dan Madu Hutan

Yeast is unicellular eukaryotic microorganism and one of the main resources in of organic compound. The natural compounds produced by yeasts have high commercial value; one of the examples is enzyme. Enzymes are widely used in industrial production processes. The invertase enzyme has the ability to catalyze sucrose, and hydrolyze it into equimolar monosaccharides, D-glucose and D-fructose mixtures called invert sugar. Invertase itself is commonly found in various parts of plants wich has high carbon content. Honey and nectar are compounds that have high carbon contents. Very high glucose and fructose contents show high levels of sucrose hydrolysis, so it is possible to have high levels of invertase enzymes in honey and nectar. This study aims to perform screening of invertase enzyme from yeasts that isolated from the nectar and forest honey and to find out the optimum temperature and pH for the enzyme production. This research was conducted by isolating yeast contained in wild honey and flowers nectar. Then conducted by qualitative test with selective medium and benedict test method. Quantitative test of intervase unit activity measured by DNS method with OD 540 nm. Protein concentration measured by Lowry Method with OD 650 nm. From 47 isolats 16 isolates able for invertase enzymes production. Yeast isolat SG 3.2 unit activity is 0.222 U/ml and specific activity is 7.07 U/mg. Optimum production pH and temperature are 5 and 25°C, respectively.

Epiphytic microalgae as biological indicators for carbon monoxide concentrations in different areas of Peninsular Malaysia

Microalgae are unicellular microorganisms with unique features and can be used as indicators for air pollutants. Microalgae have been found to withstand the negative effects of air pollutants. This study examined the relationship between the levels of carbon monoxide (CO) and the density of microalgal cells in different areas in Peninsular Malaysia, which has a hot and humid climate throughout the year. The influence of CO on the composition of microalgal species was also investigated. Microalgae samples were collected from four selected areas, chosen based on average CO readings for 2015 in the pattern of increasing values (low, medium, high) – Jerantut (low), Banting (medium), Kuala Lumpur (medium) and Petaling Jaya (high). The study found that Desmococcus olivaceus was the most widespread species found in the study areas whereas Trebouxia arboricola was the most dominant species. Trentepohlia rigidula, Coccomyxa confluens, Keratococcus bicaudatus, and Klebsormidium flaccidum can be categorised as non-tolerant to high levels of CO as they were only found in the area with low levels of CO, Jerantut. The study also showed that there was a perfect positive correlation between the CO levels and the number of microalgal cells. Data from the Jaccard Similarity Index indicates a low similarity in species composition between Jerantut and Banting, Kuala Lumpur and Petaling Jaya with Jaccard coefficients of 0.2857, 0.1250, and 0.1250, respectively. The outcomes from this study provide useful data in understanding the relationship of CO on microalgae cell density together with the composition of species and suggest the use of epiphytic microalgae as ecological indicators for air pollution.

Thermocatalytic Pyrolysis of Exhausted Arthrospira platensis Biomass after Protein or Lipid Recovery

Microalgae and cyanobacteria are unicellular microorganism that contain high-added-value compounds. To make their extraction economically feasible, the biorefinery concept is the only solution. In this study, the residues resulting from lipid or protein extraction from Arthrospira platensis biomass were valorized by catalytic pyrolysis using ZSM5 zeolite or amorphous silica–alumina as catalyst. The reaction was performed in a quartz reactor, and the catalysts were placed in a fixed bed, to force the reaction gases to pass through it. The reaction products were analyzed by FTIR and GC–MS analyses. The reaction gases and liquids obtained from the extraction residues had higher hydrocarbon contents compared with the untreated biomass. Moreover, the pyrolysis of biomass after protein extraction led to fractions with lower nitrogenated component contents, while that after lipid extraction to fractions with lower oxygenated component contents. This study showed that the pyrolysis process could be used to valorize the microalgae extraction residues, aiming to make biofuels production and extraction of high-added-value products more economically feasible.

Trap-and-release of motile microorganisms using glass-based standing surface acoustic wave devices

Standing surface acoustic waves (SSAWs) are an effective tool for cell manipulation and isolation in many biological and biomedical applications. Chlamydomonas reinhardtii, a unicellular motile microorganism, is an excellent biological model to study ciliary mechanics; however, its swimming strength is a challenge for trapping and analysis by conventional non-contact methods. SSAW devices incorporating polydimethylsiloxane (PDMS) channels are unable to hold C. reinhardtii due to inadequate acoustic trapping forces at power levels that do not induce excessive heating. Under operating conditions that are suitable for trapping, the sample temperature increases rapidly to exceed the thermotolerance threshold of the cells leading to loss of function or death . In this study, we show that SSAW devices with wet-etched glass channels allow for gentle trap-and-release of C. reinhardtii using 10 and 25 MHz ultrasound while traditional SSAW devices with PDMS channels kill the cells. In addition, we use infrared thermography to confirm that PDMS-based SSAW devices reach significantly higher temperatures than glass-based devices at comparable input powers. Glass-based SSAW devices easily generate the required trapping forces while maintaining a biocompatible thermal environment.

Development of microalgal industries in the past 60 years due to biotechnological research in China: a review

Microalgae are unicellular photosynthetic microorganisms. About 1500 years ago, at the Jin Dynasty, the Chinese consumed microalgae as food and tried its use as traditional medicines. During the “three-year period of famine” from 1959 to 1962, the central Chinese government encouraged scientists to conduct research on the cultivation of Chlorella as a food substitute, thus initiating the early developmental stage of microalgal biotechnology. A newer biotechnological innovation was conceived in the 1980s, when the national strategy which states that “ Spirulina should be taken as a protein supplement by the Chinese” was instituted. Since then several key biotechnological innovations have been developed over the past 60 years, which are related to the breeding of microalgal species, raceway pond and tubular photobioreactor technology and “from 0–1” originality of microalgal cultivation modes. In China, a series of breakthroughs as regards the biomass scaling-up of Spirulina , Chlorella , Haematococcus pluvialis , and Euglena gracilis have been achieved; this has therefore made China the largest producer of microalgal biomass globally. The core missions of the research and development of microalgal biotechnology in China are to reduce production cost, and develop new bio-economy modes for both precise application and environmental governance through microalgal biomass usage.

Humic Substances Mitigate the Impact of Tritium on Luminous Marine Bacteria. Involvement of Reactive Oxygen Species.

The paper studies the combined effects of beta-emitting radionuclide tritium and Humic Substances (HS) on the marine unicellular microorganism—luminous bacteria—under conditions of low-dose radiation exposures (<0.04 Gy). Tritium was used as a component of tritiated water. Bacterial luminescence intensity was considered as a tested physiological parameter. The bioluminescence response of the marine bacteria to tritium corresponded to the “hormesis” model: it included stages of bioluminescence inhibition and activation, as well as the absence of the effect. HS were shown to decrease the inhibition and activation effects of tritium, similar to those of americium-241, alpha-emitting radionuclide, studied earlier. Correlations between the bioluminescence intensity and the content of Reactive Oxygen Species (ROS) were found in the radioactive bacterial suspensions. The results demonstrate an important role of HS in natural processes in the regions of low radioactive contamination: HS can mitigate radiotoxic effects and adaptive response of microorganisms to low-dose radioactive exposures. The involvement of ROS in these processes was demonstrated.