Dinitrogen-Fixing Cyanobacteria in Microbial Mats of Two Shallow Coral Reef Ecosystems

Dinitrogen-fixing organisms in cyanobacterial mats were studied in two shallow coral reef ecosystems: La Reunion Island, southwestern Indian Ocean, Sesoko (Okinawa) Island, and northwestern Pacific Ocean. Rapidly expanding benthic miniblooms, frequently dominated by a single cyanobacterial taxon, were identified by microscopy and molecular tools. In addition, nitrogenase activity by these blooms was measured in situ. Dinitrogen fixation and its contribution to mat primary production were calculated using 15N2 and 13C methods. Dinitrogen-fixing cyanobacteria from mats in La Reunion and Sesoko showed few differences in taxonomic composition. Anabaena sp. among heterocystous and Hydrocoleum majus and Symploca hydnoides among nonheterocystous cyanobacteria occurred in microbial mats of both sites. Oscillatoria bonnemaisonii and Leptolyngbya spp. occurred only in La Reunion, whereas Hydrocoleum coccineum dominated in Sesoko. Other mats dominated by Hydrocoleum lyngbyaceum, Phormidium laysanense, and Trichocoleus tenerrimus occurred at lower frequencies. The 24-h nitrogenase activity, as measured by acetylene reduction, varied between 11 and 324 nmoles C2H2 reduced µg−1 Chl a. The highest values were achieved by heterocystous Anabaena sp. performed mostly during the day. Highest values for nonheterocystous cyanobacteria were achieved by H. coccineum mostly during the night. Daily nitrogen fixation varied from nine (Leptolyngbya) to 238 nmoles N2µg−1 Chl day−1 (H. coccineum). Primary production rates ranged from 1,321 (S. hydnoides) to 9,933 nmoles C µg−1 Chl day−1 (H. coccineum). Dinitrogen fixation satisfied between 5% and 21% of the nitrogen required for primary production.Ocean Development Sub-Committee of France–Japan S&T Cooperation; Mitsubishi cooperation; The Ministry of Education, Science, Sport, and Culture of Japan; Hanse Wissenschaftskolleg; Delmenhorst and Alexander-von-Humboldt Foundation; Bad Godesberg; Germany supported collaborative research on cyanobacterial diversit

Changes in microbial communities in coastal sediments along natural CO2gradients at a volcanic vent in Papua New Guinea

Natural CO2 venting systems can mimic conditions that resemble intermediate to high pCO2 levels as predicted for our future oceans. They represent ideal sites to investigate potential long-term effects of ocean acidification on marine life. To test whether microbes are affected by prolonged exposure to pCO2 levels, we examined the composition and diversity of microbial communities in oxic sandy sediments along a natural CO2 gradient. Increasing pCO2 was accompanied by higher bacterial richness and by a strong increase in rare members in both bacterial and archaeal communities. Microbial communities from sites with CO2 concentrations close to today's conditions had different structures than those of sites with elevated CO2 levels. We also observed increasing sequence abundance of several organic matter degrading types of Flavobacteriaceae and Rhodobacteraceae, which paralleled concurrent shifts in benthic cover and enhanced primary productivity. With increasing pCO2, sequences related to bacterial nitrifying organisms such as Nitrosococcus and Nitrospirales decreased, and sequences affiliated to the archaeal ammonia-oxidizing Thaumarchaeota Nitrosopumilus maritimus increased. Our study suggests that microbial community structure and diversity, and likely key ecosystem functions, may be altered in coastal sediments by long-term CO2 exposure to levels predicted for the end of the century

Забезпечення якості медичної допомоги в умовах запровадження в Україні обов'язкового медичного страхування (адміністративно-правові принципи та складові елементи)

Аналізуються адміністративно правові принципи та складові елементи забезпечення якості медичної допомоги в умовах запровадження в Україні обов’язкового медичного страхування. Особлива увага приділена питанням контролю якості медичної допомоги. Ключові слова: якість надання медичної допомоги, обов’язкове медичне страхування.Анализируются административно правовые принципы и составляющие части обеспечения качества медицинской помощи в условиях утверждения в Украине обязательного медицинского страхования. Особое внимание уделено вопросам контроля качества оказания медицинской помощи. Ключевые слова: качество медицинской помощи, обязательное медицинское страхование.Administrative and legal principles and component parts of providing medical care quality in conditions of introducing compulsory medical insurance in Ukraine are analyzed in the article. Special attention is paid to the control provision of medical care quality. Key words: medical care quality, compulsory medical insurance

Study the Effects of Reactive Materials Replacement on Some Properties of Cement Mortar

This study involves natural--materials replacement and its reaction with cement mortar behavior for many mortar samples under variable curing time with constant water to cement ratio (W/C = 0.5).In this researchsomeproperties such as (compressive strength the surface hardness and water absorption test), were affected by adding small ratios ofpowder (from (RHA) and (BRP) particles)as replacements to the Ordinary Portland Cement (OPC) / type (I). The percentages of natural materials additives replacement on the mixture of mortar include (0, 5, 10, 15 and 20%) with constant (W/C) ratio. Also the amount of the fine aggregate used was three times the amount of cement. The results showed that, the compressive strength and splitting tensile strength and water absorption of the mortars for (replacement) gives better properties than mortar without replacement in all tests. Best enhancements in properties for mortars with pozzalanic replacements were achieved at (15%) for (RHA) and 10% for (RBP) replacement from weight of cement

Living on the edge: Biofilms developing in oscillating environmental conditions

For the first time, the densities and diversity of microorganisms developed on ocean gliders were investigated using flow cytometry and Illumina MiSeq sequencing of 16S and 18S rRNA genes. Ocean gliders are autonomous buoyancy-driven underwater vehicles, equipped with sensors continuously recording physical, chemical, and biological parameters. Microbial biofilms were investigated on unprotected parts of the glider and surfaces coated with base, biocidal and chitosan paints. Biofilms on the glider were exposed to periodical oscillations of salinity, oxygen, temperature, pressure, depth and light, due to periodic ascending and descending of the vehicle. Among the unprotected surfaces, the highest microbial abundance was observed on the bottom of the glider’s body, while the lowest density was recorded on the glider’s nose. Antifouling paints had the lowest densities of microorganisms. Multidimensional analysis showed that the microbial communities formed on unprotected parts of the glider were significantly different from those on biocidal paint and in seawater

The Impact Of Oral Health Education And Preventive Measures On Dental Caries And Periodontal Diseases

Oral problems, including dental caries, periodontal diseases, and tooth loss, are significant global public health concerns. This is due to the fact that inadequate oral health has extensive impacts on general health and quality of life. In improving oral health, especially in developing countries, there are obstacles that need to be addressed. It is crucial to enhance public health programs worldwide by implementing efficient preventative measures against diseases and simultaneously boosting oral health. Frequently, collective actions are employed for the purpose of oral health education. These actions often involve delivering lectures utilizing various materials such as flipcharts, videos, PowerPoint presentations, as well as implementing other activities like supervised teeth brushing and topical fluoride application. This paper aimed to review the impact of oral health education and preventive measures on dental caries and periodontal diseases

Intracellular nitrate storage by diatoms can be an important nitrogen pool in freshwater and marine ecosystems

Identifying and quantifying nitrogen pools is essential for understanding the nitrogen cycle in aquatic ecosystems. The ubiquitous diatoms represent an overlooked nitrate pool as they can accumulate nitrate intracellularly and utilize it for nitrogen assimilation, dissipation of excess photosynthetic energy, and Dissimilatory Nitrate Reduction to Ammonium (DNRA). Here, we document the global co-occurrence of diatoms and intracellular nitrate in phototrophic microbial communities in freshwater (n = 69), coastal (n = 44), and open marine (n = 4) habitats. Diatom abundance and total intracellular nitrate contents in water columns, sediments, microbial mats, and epilithic biofilms were highly significantly correlated. In contrast, diatom community composition had only a marginal influence on total intracellular nitrate contents. Nitrate concentrations inside diatom cells exceeded ambient nitrate concentrations ∼100–4000-fold. The collective intracellular nitrate pool of the diatom community accounted for <1% of total nitrate in pelagic habitats and 65–95% in benthic habitats. Accordingly, nitrate-storing diatoms are emerging as significant contributors to benthic nitrogen cycling, in particular through Dissimilatory Nitrate Reduction to Ammonium activity under anoxic conditions

Effect of biostimulation using sewage sludge, soybean meal and wheat straw on oil degradation and bacterial community composition in a contaminated desert soil

Waste materials have a strong potential in the bioremediation of oil-contaminated sites, because of their richness in nutrients and their economical feasibility. We used sewage sludge, soybean meal and wheat straw to biostimulate oil degradation in a heavily contaminated desert soil. While oil degradation was assessed by following the produced CO2 and by using gas chromatography-mass spectrometry (GC-MS), shifts in bacterial community composition were monitored using illumina MiSeq. The addition of sewage sludge and wheat straw to the desert soil stimulated the respiration activities more than the addition of soybean meal. GC-MS analysis revealed that the addition of addition of sewage sludge and wheat straw resulted in 1.7 to 1.8 fold increase in the degraded C14 to C30 alkanes, compared to only 1.3 fold increase in the case of soybean meal addition. The degradation of ≥ 90% of the C14 to C30 alkanes were measured in the soils treated with sewage sludge and wheat straw. MiSeq sequencing revealed that the majority (76.5-86.4% of total sequences) of acquired sequences from the original soil belonged to Alphaproteobacteria, Gammaproteobacteria and Firmicutes. Multivariate analysis of operational taxonomic units (OTUs) placed the bacterial communities of the soils after the treatments in separate clusters (ANOSIM R=0.66, P=0.0001). The most remarkable shift in bacterial communities was in the wheat straw treatment, where 95-98% of the total sequences belonging to Bacilli. We conclude that sewage sludge and wheat straw are useful biostimulating agents for the cleanup of oil-contaminated desert soils