Microbial Filtrates Research Articles

Optimization of Biodegradation of Common Bean Biomass for Fermentation Using Trichoderma asperellum WNZ-21 and Artificial Neural Networks

This study showcases a promising approach to sustainably unlocking plant biomass residues by combining biodegradation with artificial intelligence to optimize the process. Specifically, we utilized the definitive screening design (DSD) and artificial neural networks (ANNs) to optimize the degradation of common bean biomass by the endophytic fungus Trichoderma asperellum WNZ-21. The optimized process yielded a fungal hydrolysate rich in 12 essential and non-essential amino acids, totaling 18,298.14 μg/g biomass. GC-MS analysis revealed four potential novel components not previously reported in microbial filtrates or plants and seven components exclusive to plant sources but not reported in microbial filtrates. The hydrolysate contained phenolic, flavonoid, and tannin compounds, as confirmed by FT-IR analysis. High-resolution transmission electron microscopy depicted structures resembling amino acid micelles and potential protein aggregates. The hydrolysate exhibited antioxidant, antibacterial, and anticancer properties and innovatively induced apoptotic modulation in the MCF7 cancer cell line. These findings underscore the potential of ANN-optimized fermentation for various applications, particularly in anticancer medicine due to its unique composition and bioactivities. The integration of the DSD and ANNs presents a novel technique for biomass biodegradation, warranting the valorization of plant biomass and suggesting a further exploration of the new components in the fungal hydrolysate. This approach represents the basic concept for exploring other biomass sources and in vivo studies.

A High Efficiency, Low Resistance Antibacterial Filter Formed by Dopamine-Mediated In Situ Deposition of Silver onto Glass Fibers.

The coating of filter media with silver is typically achieved by chemical deposition and aerosol processes. Whilst useful, such approaches struggle to provide uniform coating and are prone to blockage. To address these issues, an in situ method for coating glass fibers is presented via the dopamine-mediated electroless metallization method, yielding filters with low air resistance and excellent antibacterial performance. It is found that the filtration efficiency of the filters is between 94 and 97% and much higher than that of silver-coated filters produced using conventional dipping methods (85%). Additionally, measured pressure drops ranged between 100 and 150Pa, which are lower than those associated with dipped filters (171.1Pa). Survival rates of Escherichia coli and Bacillus subtilis bacteria exposed to the filters decreased to 0 and 15.7%±1.49, respectively after 2h, with no bacteria surviving after 6 h. In contrast, survival rates of E. coli and B. subtilis bacteria on the uncoated filters are 92.5% and 89.5% after 6 h. Taken together, these results confirm that the in situ deposition of silver onto fiber surfaces effectively reduces pore clogging, yielding low air resistance filters that can be applied for microbial filtration and inhibition in a range of environments.

Metagenomic 18S rDNA reads revealed zonation of eukaryotic communities in the Yongle blue hole.

The Yongle blue hole (YBH), situated in the South China Sea, represents a compelling subject of study in marine microbiology due to its unique redox-layered microbial ecosystems. However, the diversity and ecology of microbial eukaryotes within the YBH remains underexplored. This study endeavors to bridge this gap through the application of the in situ microbial filtration and fixation (ISMIFF) device to collect 0.22-30 μm microbial samples from 21 water layers of YBH. Subsequent extraction of 18S rRNA metagenomic reads of 21 metagenomes and 10 metatranscriptomes facilitated a comprehensive analysis of community structures. Findings revealed a pronounced superiority in the diversity and richness of eukaryotic microorganisms in the oxic zone compared to its suboxic and anoxic counterparts. Notably, Dinophyceae and Maxillopoda emerged as the predominant taxa based on the analysis of the 18S rRNA reads for the V4 and V9 regions, which showed stratification In their relative abundance and suggested their potential role in the thermo-halocline boundaries and oxic-anoxic interface. Specifically, In these eukaryotic microbial communities, Dinophyceae exhibited significant abundance at 20 m (20.01%) and 105 m (26.13%) water depths, while Maxillopoda was prevalent at 40 m (22.84%), 80 m (23.19%), and 100 m (15.42%) depths. A part of these organisms, identified as larvae and protists, were likely attracted by swarming chemosynthetic bacterial prey prevailing at the thermo-halocline boundaries and oxic-anoxic interface. Furthermore, the phylogenetic relationships of the major 18S operational taxonomic units (OTUs) showed a close adjacency to known species, except for three Dinophyceae OTUs. In conclusion, this study provides critical insights into the vertical distribution and transcriptional activity of <30-μm eukaryotic microbes, shedding light on the taxonomic novelty of eukaryotic microorganisms within the semi-enclosed blue holes.

اختبار التأثير التثبيطي لمركب Tricin ضد بعض البكتريا التي تنتقل عن طريق الاغذية وتقدير المعامل الفينولي له

The inhibitory effect of the hot aqueous extract of commercial jasmine rice bran (HAE) and the purified tricin compound on the growth of some food-borne pathogenic bacteria (Escherichia coli, E. coli O157:H7, Salmonella typhimurium, Salmonella typhi, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella spp, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis) and compared with phenol coefficient using several dilutions of water: purified tricin (70:1, 90:1, 1:100, 1:120 and 1:150). and water: purified tricin (70:1, 90:1 and 1:100),at the same concentration, sterilized with microbial filters .Tricin purified showed higher efficiency then the aqueous extract HAE against growth of gram-positive and negative bacteria. The highest significant inhibition activity of purified Tricin compound was at P≤0.05 effect against B. subtilis , B. cereus and S. aureus with inhibitory diameter of 29, 27.5 and 27.5 mm respectively. White the aqueous extract HAE had loupe effectiveness than it against the same bacteria with a diameter of inhibition7,8.5 and 10.5 mm respectively After incubation at 37°C for 24 h, the last reading was the highest inhibition activity of the extract HAE. As for the results of the susceptibility of tricin as an antiseptic towards Gram-negative bacteria S. typhi and Gram-positive S. aureus compared to phenol using several dilutions of each, high dilutions had a clear inhibition in the growth of S. aureus and S. typhi bacterial isolates, especially when compared with phenol when The higher dilution (1:100) showed bacterial growth, while we did not find growth for these isolates at the same dilution coefficient of tricin for periods (5, 10, and 15) min After incubation at 37°C for 48 h. S. typhi was less sensitive than S. aureus towards phenol and tricin.

Discovery of Prevalent Ciliophora, Discoba, and Copepoda Protists in Deep Sea Water by In Situ Nucleotide Extraction

Deep-sea eukaryotic microorganisms play a vital role in degrading organic matter and geochemically cycling elements in the deep ocean. However, the impact of sampling methods on detection of these microorganisms under high hydrostatic pressure remains uncertain. In this study, we compared a traditional water sampling method using a Niskin bottle, an in situ microbial filtration and fixation method (ISMIFF), and a multiple in situ nucleic acid collection (MISNAC) method to exhibit differences in the community structures that were collected at ~590–3100 m in the South China Sea (SCS). The classification and biodiversity indices of 18S rDNA Illumina sequencing reads from the V9 variation region revealed higher diversity for MISNAC DNA absorption column samples compared to others. Importantly, the relative abundance of Ciliophora (19.49%), Copepoda (23.31%), and Diplonemea (10.67%) was higher in MISNAC adsorption column samples, while Retaria (48.86%) were dominant in the MISNAC membrane samples. This indicates that MISNAC columns might collect more DNA in situ for the naked protists, while Retaria with a carbonate shell were more likely retained on the membrane. In conclusion, MISNAC is an effective method for DNA collection of deep-sea eukaryotic microorganisms and provides valuable materials for studying deep-sea microbial ecosystems.

Metagenomic 16S rDNA reads of in situ preserved samples revealed microbial communities in the Yongle blue hole.

Our knowledge on biogeochemistry and microbial ecology of marine blue holes is limited due to challenges in collecting multilayered water column and oxycline zones. In this study, we collected samples from 16 water layers in Yongle blue hole (YBH) located in the South China Sea using the in situ microbial filtration and fixation (ISMIFF) apparatus. The microbial communities based on 16S rRNA metagenomic reads for the ISMIFF samples showed high microbial diversity and consistency among samples with similar dissolved oxygen levels. At the same depth of the anoxic layer, the ISMIFF samples were dominated by sulfate-reducing bacteria from Desulfatiglandales (17.96%). The sulfide concentration is the most significant factor that drives the division of microbial communities in YBH, which might support the prevalence of sulfate-reducing microorganisms in the anoxic layers. Our results are different from the microbial community structures of a Niskin sample of this study and the reported samples collected in 2017, in which a high relative abundance of Alteromonadales (26.59%) and Thiomicrospirales (38.13%), and Arcobacteraceae (11.74%) was identified. We therefore demonstrate a new profile of microbial communities in YBH probably due to the effect of sampling and molecular biological methods, which provides new possibilities for further understanding of the material circulation mechanism of blue holes and expanding anoxic marine water zones under global warming.

Tree seedling shade tolerance arises from interactions with microbes and is mediated by functional traits

Shade tolerance is a central concept in forest ecology and strongly influences forest community dynamics. However, the plant traits and conditions conferring shade tolerance are yet to be resolved. We propose that shade tolerance is shaped not only by responses to light but also by a species’ defense and recovery functional traits, soil microbial communities, and interactions of these factors with light availability. We conducted a greenhouse experiment for three temperate species in the genus Acer that vary in shade tolerance. We grew newly germinated seedlings in two light levels (2% and 30% sun) and controlled additions of microbial filtrates using a wet-sieving technique. Microbial filtrate treatments included: &amp;lt;20 µm, likely dominated by pathogenic microbes; 40-250 µm, containing arbuscular mycorrhizal fungi (AMF); combination, including both filtrate sizes; and sterilized combination. We monitored survival for nine weeks and measured fine root AMF colonization, hypocotyl phenolics, stem lignin, and stem+root nonstructural carbohydrates (NSC) at three-week intervals. We found that differences in seedling survival between low and high light only occurred when microbes were present. AMF colonization, phenolics, and NSC generally increased with light. Phenolics were greater with &amp;lt;20 µm microbial filtrate, suggesting that soil-borne pathogens may induce phenolic production; and NSC was greater with 40-250 µm filtrate, suggesting that mycorrhizal fungi may induce NSC production. Across species, microbe treatments, and light availability, survival increased as phenolics and NSC increased. Therefore, shade tolerance may be explained by interactions among soil-borne microbes, seedling traits, and light availability, providing a more mechanistic and trait-based explanation of shade tolerance and thus forest community dynamics.

Enhancing durability and sustainable preservation of Egyptian stone monuments using metabolites produced by Streptomyces exfoliatus

Despite their threatens for Egyptian stone monuments, A few studies focused on using biocontrol agents against deteriorative fungi and bacteria instead of using chemical assays that leave residuals leading to human toxicity and environmental pollution. This work aims to isolate and identify fungal and bacterial isolates that showed deteriorative activities from stone monuments in Temple of Hathor, Luxor, Egypt, as well as determine the inhibitory activity of metabolites produced by Streptomyces exfoliatus SAMAH 2021 against the identified deteriorative fungal and bacterial strains. Moreover, studying the spectral analysis, toxicological assessment of metabolites produced by S. exfoliatus SAMAH 2021 against health human cell fibroblast, and colorimetric measurements on the selected stone monuments. Ten samples were collected from Temple of Hathor, Luxor, Egypt. Three fungal isolates and one bacterial isolate were obtained and identified as A. niger isolate Hathor 2, C. fioriniae strain Hathor 3, P. chrysogenum strain HATHOR 1, and L. sphaericus strain Hathor 4, respectively. Inhibitory potential of the metabolites in all concentrations used (100–25%) against the recommended antibiotics (Tetracycline 10 µg/ml and Doxycycline (30 µg/ml) showed an inhibitory effect toward all tested deteriorative pathogens with a minimum inhibition concentration (MIC) of 25%. Cytotoxicity test confirmed that microbial filtrate as the antimicrobial agent was safe for healthy human skin fibroblast with IC50 of < 100% and cell viability of 97%. Gas chromatography analysis recorded the existence of thirteen antimicrobial agents, Cis-vaccenic acid; 1,2-Benzenedicarboxylic acid; ç-Butyl-ç-butyrolactone and other compounds. Colorimetric measurements confirmed no color or surface change for the limestone-treated pieces. The use of the metabolite of microbial species antimicrobial as a biocontrol agent raises contemporary issues concerning the bio-protection of the Egyptian monuments to reduce chemical formulas that are toxic to humans and pollute the environment. Such serious problems need further investigation for all kinds of monuments.

Analysis of Particulate and Microbiological Filtration Performance of Air Handling Unit Filters in a Low-Energy Office Building over 12 Months

Indoor air quality is an important consideration for the health and well-being of building occupants, and the SARS CoV-2 pandemic highlighted the importance of maintaining proper ventilation in buildings. Air handling units (AHUs) are used to provide fresh air and maintain occupant comfort. The objective of this work was to study the evolution of filtration efficiency in an AHU fitted with bag filters, installed to treat office air in a low-energy building, over a 12-month period. The particulate filtration efficiency (PFE) and the microbial filtration efficiency (MFE) were quantified by measuring particle size distribution and bacterial and fungal concentration in the air circulating in the AHU. The resulting microbial concentration measurements in the fresh air (between 10²–103 CFU/m3 for fungi and around 103 CFU/m3 for bacteria) were higher than those in the extracted air from the offices (between 101 and 102 CFU/m3 for fungi and around 102 CFU/m3 for bacteria). The PFE and MFE measured were almost constant throughout the 12 months, with an increase of the filter pressure drop from 70 to 90 Pa. The PFE and MFE were quite comparable for a particle diameter. Therefore, the measurement of PFE is a reliable indicator of the MFE.

Microbial Adhesion on Circular Obstacles: An Optimization Study

Microbial filtration is an important process with applications in environmental, mining, and sanitary engineering. Here, we study the interplay between the motility of microswimmers and the imposed flow to determine the adhesion of bacteria at the surface of the solid obstacle. For that, we perform numerical simulations of active Brownian particles interacting with a single cylindrical obstacle when an imposed laminar flow is present. Highly and weakly persistent swimmers are studied, representing extreme cases of bacteria used in experiments and we vary the swimmers’ velocity u0, the imposed flow velocity U∞, and the obstacle radius R. Starting with no swimmers close to the cylinder, we inject them steadily until a constant number of swimmers are adhered to the obstacle surface. The deposition/erosion process is characterized by the number of bacteria in contact with the obstacle, quantified by the average coverage of the cylinder surface λtrap, and the relaxation time to reach the steady state τtrap. Two regimes are found. The Brownian deposition is attained when swimmer velocities are smaller than the imposed flow. In this case, the particles can diffuse across the streamlines and settle around the obstacle covering the whole perimeter, forming multiple layers. The direct interception is obtained when the particle’s velocities are larger, reaching the obstacle by direct swimming, in which case they form approximately one layer on the obstacle surface. It is found that λtrap decreases with u0 and R, but the dependence with the imposed flow U∞ is non-monotonic, with and optimum coverage for intermediate flows, given by the crossover of the two regimes. The relaxation rate τtrap decreases with u0 and increases with R. The dependence of τtrap with U∞ is more complex, depending on the persistence of the swimmers. The existence of an optimum value of the flow velocity to reach maximum values of the number of deposited swimmers is an important design information for different applications that use microbial filtration. Finally, in general, it is found that optimal adhesion that has larger values of λtrap and smaller values of τtrap is obtained for more-persistent swimmers moving at small velocities interacting with small obstacles.

Investigation The Bacterial Filtration Efficiency Of Medical Masks From Polyethylene Terephthalate (PET) Fabric

The Covid-19 pandemic period caused attention to the importance of medical masks. Various studies show that mask fabrics should not be ordinary. Uncontrollably produced masks with poor quality have become an important problem in the market. Based on the idea that viruses spread by binding themselves to environmental bacteria and water droplets, it is assumed that the basic filtering efficiency of masks is of primary importance and requires the use of masks with a certain filtering ability. The purpose of the present study was to produce fabric masks from Polyethylene Terephthalate (PET), and to investigate the filtration efficiency. Masks were produced from the developed PET fabric and widely used Meltblown (MB) fabric, which is known to have a high filtration rate and their filtration efficiencies were compared. EN 14683 BFE methods was used in laboratory setting to measure the filtration efficiency of the masks. It was found that the MB/3-layer mask had 99.7% (SD±0.2) capacity of filtering microorganisms and the 3-layer ART/Mask in the developed PET structure was capable of filtering microorganisms at a rate of 96.8% (SD±2.7). When the filtration efficiency of the masks detected for each microorganism was compared separately, no statistically significant differences were detected (p>0.05). The tested mask was found to have a similar high microbial filtration rate to the mask made of meltblown fabric. This suggests that it will reduce the spread of viruses by attaching themselves to bacteria from sick individuals. It is also it can has protective effect for nosocomial infections.

Efektivitas Jenis Bahan Masker Kain Berdasarkan Kemampuan Penyaringan Mikroba

A cloth mask is a mask that can be used repeatedly and is made of thicker fabric material. Cloth masks circulating in the community have not guaranteed quality. This study aims to find out the effectiveness of fabric mask materials based on microbial filtration capabilities as well as find out the optimal characteristics of the initial use of cloth mask materials and after washing 50 times. This study was conducted experimentally where the effectiveness of fabric mask material by spraying bacterial suspension, and testing the characteristics of fabric mask materials by conducting fiber observation, light intensity test, steam filtration test, water absorption test and water capillary on the fabric. The results of research on the effectiveness of fabric mask materials showed Asymp.Sig &gt;0.05 so that there are significant differences from all types of fabric mask materials. Based on the results of characteristic testing, the fiber material of the initial cloth mask looks better than after 50 washes. Test the light intensity of the outer layer, inner layer, and filter layers p, f and s after washing there is an increase compared to the initial use. Steam filtration tests of outer layers, inner layers and filter layers p, f and s when the initial user takes time for steam to penetrate the fabric compared to 50 washes. The absorption test of the outer layer during initial use does not occur absorption above 60 seconds and after 50 washes begins absorption. The inner layer and filter layer at the initial use do not absorb above 60 seconds and after 50 washes there is absorption under 60 seconds. The p filter layer does not absorb during initial use and after 50 washes. Filter layer f during initial use and after 50 washes there is absorption under 60 seconds. Capillary test results for 60 seconds the outer layer and the p filter layer during initial use do not absorb while 50 times the washing occurs absorption. The inner layer, filter layer f and s increase after 50 washes. The conclusion of the study was that the effectiveness of the mask material was good enough for the inner and outer layers, the p filter layer was more effective than the f and s filter layers. The characteristic test results at initial use were very good, but after 50 washes there was a decrease.

Biological treatment of asbestos cement wastes by Aspergillus niger and Acidithiobacillus thiooxidans

Asbestos cement materials used in the past by the building construction sector still poses environmental problems, requiring proper treatment and storage. Here we investigated an alternative microbiological-induced treatment of raw chrysotile and asbestos cement materials. Based on the knowledge that some microorganisms, such as Aspergillus niger (fungus) and Acidithiobacillus thiooxidans (bacteria) are potential organic or inorganic acid producers, we evaluated the dissolution of the chrysotile structure, which is the toxic component in these materials, under submerged and solid-state cultivation conditions. The Mg, and Ca release percentage evaluated and SEM/EDX, XRD, and FTIR characterization data have shown a high potential of both microorganisms studied to total chrysotile degradation (up to 100%, based on Mg content), using either the microbial filtrate, submerged and solid-state cultivation. The present study is a potential biological treatment of asbestos cement materials that can also be applied in situ in areas contaminated with asbestos, which is an alternative not applied to energy-intensive methods such as mechanochemical or thermal treatment.

Acaulospora as the Dominant Arbuscular Mycorrhizal Fungi in Organic Lowland Rice Paddies Improves Phosphorus Availability in Soils

Flooding in rainfed lowlands greatly impairs the mutualistic relationship between indigenous arbuscular mycorrhizal fungi (AMF) and rice. In flooded soils, root colonization by AMF is arrested, but some AMF genera, defined as the core AMF, remain present. However, the core AMF in rainfed lowlands and their symbiotic roles remain unknown. Here, we showed that Acaulospora fungi were the core AMF in rice seedling roots of the Sangyod Muang Phatthalung (SMP) landrace rice variety grown in non-flooded and flooded paddy soils. Subsequently, indigenous Acaulospora spores were propagated by trap cultures using maize as the host plants. Therefore, to clarify the roles of cultured Acaulospora spores in a symbiotic partnership, the model japonica rice variety Nipponbare was grown in sterile soil inoculated with Acaulospora spores, and recolonized with a native microbial filtrate from the organic rice paddy soil. Our data demonstrated that the inoculation of Acaulospora spores in well-drained soil under a nutrient-sufficient condition for six weeks enabled 70 percent of the rice roots to be colonized by the fungi, leading to higher phosphate (Pi) accumulation in the mycorrhizal roots. Unexpectedly, the growth of rice seedlings was significantly suppressed by inoculation while photosynthetic parameters such as fractions of incoming light energy and relative chlorophyll content were unaltered. In the soil, the Acaulospora fungi increased soil phosphorus (P) availability by enhancing the secretion of acid phosphatase in the mycorrhizal roots. The findings of this work elucidate the symbiotic roles of the dominant Acaulospora fungi from lowland rice paddies.

Dust and microbial filtration performance of regular and antimicrobial HVAC filters in realistic conditions

Two polypropylene HVAC electret filters: a regular filter and an antimicrobial filter containing zinc pyrithione (ZPT), were compared for filtration performance. The study was conducted over 7 months in realistic conditions with semi-urban outdoor air. Several parameters were monitored over the study period: the average temperature was about 20 °C and relative humidity about 60%, the average inlet concentration of cultivable microorganisms was 50 CFU m-3, the average inlet concentration of particles was 10 μg m-3, the filter pressure drop increased moderately by about 30 Pa, and the particle collection efficiency of soda fluorescein (median diameter 0.35 μm) decreased in the first half of the study period by about 30% and then stabilized. The microbial concentration on the filters was quantified every 2 months using an innovative methodology based on media coupons in conjunction with microorganism quantification by CFU counting, with 5 culture media favorable to bacteria and/or fungi growth. The microbial concentrations on the filters were between 100 and 2000 CFU cm-2. The antimicrobial effect of zinc pyrithione was confirmed by the fungi cultivated with DRBC agar: no effects in the level of filter clogging were revealed in the range studied. The high statistical deviation in the results regarding the inhibiting effect of zinc pyrithione on bacteria prevents any conclusion.

Novel Systems and Membrane Technologies for Carbon Capture

Due to the global menace caused by carbon emissions from environmental, anthropogenic, and industrial processes, it has become expedient to consider the use of systems, with high trapping potentials for these carbon-based compounds. Several prior studies have considered the use of amines, activated carbon, and other solid adsorbents. Advances in carbon capture research have led to the use of ionic liquids, enzyme-based systems, microbial filters, membranes, and metal-organic frameworks in capturing CO2. Therefore, it is common knowledge that some of these systems have their lapses, which then informs the need to prioritize and optimize their synthetic routes for optimum efficiency. Some authors have also argued about the need to consider the use of hybrid systems, which offer several characteristics that in turn give synergistic effects/properties that are better compared to those of the individual components that make up the composites. For instance, some membranes are hydrophobic in nature, which makes them unsuitable for carbon capture operations; hence, it is necessary to consider modifying properties such as thermal stability, chemical stability, permeability, nature of the raw/starting material, thickness, durability, and surface area which can enhance the performance of these systems. In this review, previous and recent advances in carbon capture systems and sequestration technologies are discussed, while some recommendations and future prospects in innovative technologies are also highlighted.

Multiple in situ Nucleic Acid Collections (MISNAC) From Deep-Sea Waters

To obtain an accurate picture of microbial processes is essential for in-depth understanding of the dynamics of microbial communities and metabolic potentials. In this study, an apparatus for automatic multiple in situ nucleic acid collections (MISNAC) loaded and controlled by a lander was designed and applied for in situ microbial filtration, cell lysis and nucleic acid collection at different time points during three cruises in the South China Sea. The MISNAC apparatus completed 390 L in situ water filtration and collected a total of 1,176 ng DNA with six working units in four deployments at ~1,000 m depth. Microbial community structures in water samples obtained by the MISNAC and in situ microbial filtration and fixation (ISMIFF) apparatus, respectively, were compared by analyzing sequences of 16S rRNA amplicons. The result showed that these communities were largely consistent, regardless of the differences in the communities in the samples from different cruises and time points. In addition, the transcriptomes of the samples collected by the MISANC and a Niskin bottle dramatically differed in abundance and diversity of 16S rRNA gene reads, indicating that more in situ RNA molecules were preserved by the MISNAC, compared to the Niskin. The application of the MISNAC apparatus paved the way to time-series changes of deep-sea microorganisms and their response to various environmental factors.

Negative plant-soil feedbacks are stronger in agricultural habitats than in forest fragments in the tropical Andes.

There is now strong evidence suggesting that interactions between plants and their species-specific antagonistic microbes can maintain native plant community diversity. In contrast, the decay in diversity in plant communities invaded by nonnative plant species might be caused by weakening negative feedback strengths, perhaps because of the increased relative importance of plant mutualists such as arbuscular mycorrhizal fungi (AMF). Although the vast majority of studies examining plant-soil feedbacks have been conducted in a single habitat type, there are fewer studies that have tested how the strength and direction of these feedbacks change across habitats with differing dominating plants. In a fragmented montane agricultural system in Colombia, we experimentally teased apart the relative importance of AMF and non-AMF microbes (a microbial filtrate) to the strength and direction of feedbacks in both native and nonnative plant species. We hypothesized that native tree species of forest fragments would exhibit stronger negative feedbacks with a microbial filtrate that likely contained pathogens than with AMF alone, whereas nonnative plant species, especially a highly invasive dominant grass, would exhibit overall weaker negative feedbacks or even positive feedbacks regardless ofthe microbial type. We reciprocally inoculated each of 10 plant species separately with either the AMF community or the microbial filtrate originating from their own conspecifics, or with the AMF or microbial filtrate originating from each of the other nine heterospecific plant species. Overall, we found that the strength of negative feedback mediated by the filtrate was much stronger than feedbacks mediated by AMF. Surprisingly, we found that the two nonnative species, Urochloa brizantha and Coffea arabica, experienced stronger negative feedbacks with microbial filtrate than did the native forest tree species, suggesting that species-specific antagonistic microbes accumulate when a single host species dominates, as is the case in agricultural habitats. However, negative feedback between forest trees and agricultural species suggests that soil community dynamics may contribute to the re-establishment of native species into abandoned agricultural lands. Furthermore, our finding of no negative feedbacks among trees in forest fragments may be due to a loss in diversity of those microbes that drive diversity-maintaining processes in intact tropical forests.

Interval analysis of blood filtration efficacy in novel device for autotransfusion in postpartum hemorrhage

Postpartum haemorrhage (PPH), the leading cause of maternal mortality, is particularly problematic in low resource settings where access to safe blood supplies and definitive medical treatment is limited. We describe the continued development of an autotransfusion device designed to treat PPH by collection, filtration and infusion of maternal blood. Previous study has demonstrated that the device effectively moves blood through a filtration apparatus and removes up to 97% of aerobic bacteria but had poor anaerobic bacteria reduction. In this study, we investigate the filtration efficacy of the device using configurations comprised of three different leukocyte depletion filter designs: the Pall Leukoguard RS leukocyte reduction filter (PLRF), the Haemonetics BPF4™ (BPF4) leukocyte reduction filter, and the Haemonetics SCRC Leukotrap® (SCRC) filter. All configurations performed well with reductions ranging from 49 to 98%. Configurations containing 2 Haemonetics SCRC Leukotrap®filters (configuration 5 and 6) consistently reduced anaerobic bacteria by at least 73%. These results indicate that utilising a combination of SCRC and PLRF filters confers a high level of microbial filtration with improved removal of anaerobic organisms.

Hadal water sampling by in situ microbial filtration and fixation (ISMIFF) apparatus

The deepest point of the oceans is over 10 km depth and is characterized with extremely high hydrostatic pressure. Water sampling from the hadal zone for microbiological studies is therefore difficult. In this study, we demonstrate the application of an in situ microbial filtration and fixation (ISMIFF) apparatus in sampling work from the Challenger Deep. A total of 2300 L hadal waters were filtered by the ISMIFF equipped on a hadal lander during seven deployments. The microbial communities in the hadal samples (>6000 m) collected by the ISMIFF were composed of more heterotrophic Marinimicrobia and less photoautotrophic Prochlorococcus and SAR11 bacteria, compared with those by Niskin bottles. Such a difference in the community structure was not observed in the samples collected by the two methods from ~5000-m depth, indicating an effect of greater depths on sample quality. Our results indicate that the ISMIFF or similar filtration apparatuses are indispensable for hadal water sampling since using Niskin bottles is probably difficult to obtain pristine samples from the hadal zone. Application of the ISMIFF will pave the way to meta-omics studies on the hadal microbes.