Bacterial Accumulation Research Articles

A Natural Feed Additive Phytobiotic, Pomegranate (Punica granatum L.), and the Health Status of Poultry

Abstract The addition of antibiotic growth promotors in poultry diets results in a development of resistant bacterial strains and accumulation of drug residues in the meat and eggs. The new trend in poultry industry is the dietary addition of natural feed additives including phytobiotics. Pomegranate (Punica granatum L.) is a natural cheap feed source that has been extensively used in the livestock production. In poultry production system, pomegranate by-products such as peel powder or extract, seed oil, or juice showed high nutritional values, several health benefits, and good economic profits. Pomegranate displays a growth promoting effect and an enhancement of carcass traits of broilers, along with an improvement of the egg production traits parameters. Moreover, dietary pomegranate by-products showed a potential antioxidant and antimicrobial effects on the treated birds. Modulation of both humeral and cell mediated immune response, hypo-lipidemia, as well as enhancement of liver functions have been proved following dietary treatment with different pomegranate by-products. Therefore, this review article was designed to present the different effects of dietary pomegranate by-products on the production indices of broilers and layers, the antioxidant, antimicrobial, and immune status, as well as the blood parameters.

Difference in Intestine Content of Caenorhabditis elegans When Fed on Non-Pathogenic or Pathogenic Bacteria.

We investigated the bacterial food digestion and accumulation in wild-type adult Caenorhabditis elegans (C. elegans) worms that have fed on either non-pathogenic RFP-expressing Escherichia coli (E. coli) OP50 or pathogenic-RFP-expressing Pseudomonas aeruginosa (P. aeruginosa) PAO1 during the first 4 days of adulthood. Once the worms had completed their planned feeding cycles, they were loaded on microfluidic chips, where they were fixed to allow high-resolution z-stack fluorescence imaging of their intestines utilizing a Spinning Disk Confocal Microscope (SDCM) equipped with a high-resolution oil-immersion objective (60×). IMARIS software was used to visualize and analyze the obtained images, resulting in the production of three-dimensional constructs of the intestinal bacterial load. We discovered two distinct patterns for the bacteria-derived fluorescence signal in the intestine: (i) individual fluorescent spots, originating from intact bacteria, were present in the fluorescent E. coli-OP50-fed worms, and (ii) individual fluorescent spots (originating from intact bacteria) were dispersed in large regions of diffuse fluorescence (RDF), originating from disrupted bacteria, in fluorescent P. aeruginosa-PAO1-fed worms. We performed a semi-automated single-worm-resolution quantitative analysis of the intestinal bacterial load, which showed that the intestinal bacterial load generally increases with age of the worms, but more rapidly for the fluorescent P. aeruginosa-PAO1-fed worms.

Comparative Evaluation of Antibacterial Efficacy of Cetylpyridinium Chloride and Chlorhexidine Gluconate Mouthwashes after Periodontal Surgery - A Randomized Clinical Study

Background: Periodontitis affects 20-50 percent population is and has various systemic interrelationship. Treatment of periodontal disease requires a holistic approach. Prevention of bacterial accumulation at surgical site is crucial to minimize post-operative complications. The principal cause of post-surgical infection is bacterial colonization due to the wicking effect of the sutures. Despite numerous factors, pathogenic biofilm formation continues to play a crucial role in disease progression. Hence, a comprehensive approach with the goals of infection control, periodontal tissue regeneration, and function restoration becomes a necessity. In this study, we assessed the antibacterial efficacy of Chlorhexidine (CHX) and Cetylpyridinium Chloride (CPC) mouthwashes after periodontal surgery. Material and Methods: In this single-centric, prospective, randomized study, patients undergoing various periodontal surgeries including flap procedures, crown lengthening, resective osseous surgeries, implant placement and periodontal plastic procedures following placement of simple interrupted sutures using monofilament PTFE sutures to reduce the wicking effect. Patients included were >18 years of age, while those with any systemic diseases, pregnant and lactating women, smokers or any other deleterious habits, immune and mental disorders, unwilling to participate were excluded from the study. A total of 46 patients were randomized using envelope method to either one of the two types of mouthwashes CHX or CPC for 10 days post-periodontal surgeries and the sutures were removed after 10 days for CFU analysis. Results: Out of total 46 participants more than half were males (26) and the mean age of participants was 32.53 years (range 18-65 years). Maximum periodontal surgeries were flap procedures (21) and crown lengthening (15) while remaining included osseous surgery (5), perioplastic procedures (3) and implant procedures (2). There was a statistically significant difference seen for the values between the groups. Group I CPC had average CFU count (Mean 1.2x1010) Group II CHX had (Mean 1.2x108) The p value of Mann-Whitney U test was <0.01. Conclusion: Though the bacterial load was reduced by both types of mouthwashes, our study observed better antibacterial effectivity with CHX as compared to CPC. The findings of the study also highlighted the importance of careful adjuvant therapies regardless of the type of periodontal surgery. Keywords: Periodontal surgery, Cetylpyridinium chloride, Chlorhexidine gluconate, mouthwashes, periodontitis, biofilm, Plaque, Wound healing.

Bacterial community profiling associated with pearl culture facilities of Liusha Bay, the largest marine pearl culture base on the western Guangdong coast, South China

A large number of aquaculture facilities produced during the farming process are made of plastics. These plastics can be a distinct habitat for bacteria due to their unique materials. Therefore, this paper focuses on plastic aquaculture facilities and investigates the impact of bacterial accumulation on plastic surfaces. In this study, the high-throughput sequencing of 16S rRNA was conducted to investigate bacterial community profiling associated with the pearl culture facilities (cultured net cages and foam buoys) and surrounding water of Liusha Bay. Alpha diversity analysis showed that the richness and diversity indexes of bacterial communities in pearl culture facilities were higher than those in the aquatic environment. The richness and diversity indexes of bacterial communities were different between cultured net cages and foam buoys. Spatially influenced bacterial communities attached to pearl culture facilities varied between aquaculture areas. Thus, plastic has become a habitat for bacteria, floating in the marine environment and providing a favorable living environment for marine microorganisms and specific preferences for different substrate types. The relative abundance of certain functions on the attached bacterial community of the culture facility was high, which suggested that plastics did not only alter community structure but also influenced bacterial function. In addition, we detected small amounts of pathogenic bacteria, such as Vibrio and Bruegeria, in pearl culture facilities and surrounding seawater, suggesting that plastics can act as vectors for potentially pathogenic bacteria that may have an impact on the development of aquaculture. Our understanding of plastic ecology has been enriched by the discovery of the various microbial assemblages that can occur in aquaculture facilities.

Quaternary Phosphonium Salt-functionalized Graphene Filter for Effective Water Disinfection

To access safe water, a facile and low-cost quaternary phosphonium salt-functionalized graphene filter (PYQP-G filter) was developed via pi-pi stacking interaction between perylene and graphene surface. We first synthesized a new perylene derivative with two QPS groups at its amide sides denoted as PYQP. Next, shellac was used as a carbon source to coat the graphene material onto the surface of a porous SiO2 substrate in a chemical vapor deposition (CVD) process. Thus, a graphene filter (G-filter) was obtained. Third, the PYQP was attached to the graphene surface through π-π stacking to generate the PYQP-G filter. Due to the high bacterial accumulation and killing ability of the assembled PYQP, the PYQP-G filter showed high efficiency in water disinfection. When the bacterial concentration is blown at 105 CFU/mL, one PYQP-G filter can purify up to 500 ml of water.

Effective Modalities of Periodontitis Induction in Rat Model.

Induction of periodontal disease using the rat model is the preferred model for human periodontal disease studies that are related to gene expression, mechanisms of inflammatory regulation, microbial and host responses, resolution, and the healing process. There are 3 methods that are frequently used to induce periodontal disease, which are: ligature application, oral bacterial inoculation, and the lipopolysaccharide injection technique. In the ligature model, sterile non-absorbable sutures or orthodontic wires are widely used to induce local irritation and bacterial plaque accumulation. Secondly, mono and mixed cultures of periodontal bacteria are inoculated orally by gavage or topical application. Lastly, lipopolysaccharide extracted from pathogenic bacteria can be directly injected into the gingival sulcus to induce inflammation and stimulate osteoclastogenesis and alveolar bone loss. Among these methods, ligature application induces inflammation and alveolar bone resorption more promptly compared to other methods. This review will provide an overview of the main induction methods in experimental periodontal disease, with their advantages and disadvantages.

Comparative evaluation of Chlorhexidine and Triphala with Rajat Bhasma jelly as against Chlorhexidine mouth rinse in prevention of bacterial accumulation in fixed orthodontic assembly: A randomized interventional study

Background: By offering numerous mechanical retention sites, fixed orthodontic treatment increases the build-up of bacterial plaque, rendering teeth more susceptible to gingivitis and periodontitis. Chlorhexidine is a frequently utilised adjuvant to mechanical oral hygiene techniques and is regarded as the gold standard. As compared to chemicals and allopathy, nowadays patients are showing great inclination for the herbal products. Commercially available herbal mouhrinses are emerging in the market. Due to their lack of purity, these is a need for more herbal alternative mouthrinses like Triphala. As known, silver coated wire has antimicrobial and antiadherent properties, still not commercially available. Some reasons could be cost, toxicity levels, etc. Thereby, to evaluate the effects herbal mouthwashes in adjunct with herbal form of silver i.e. Rajat bhasma, present study has been taken up to check the antimicrobial and anti-adherent properties with various combinations Objectives: 1. To evaluate the efficacy of chlorhexidine mouthrinse and Rajat bhasma jelly as an antimicrobial agent 2. To evaluate the efficacy of Triphala mouthrinse and Rajat bhasma jelly as an antimicrobial agent 3. To compare the antimicrobial potency of chlorhexidine, triphala with rajat bhasma jelly combinations as against chlorhexidine on bacterial accumulation (streptococcus mutans and lactobacillus). Methods: Plaque will be collected from the left molar to right molar of the upper arch with a disinfected curette at 3 time periods: T 0 = just prior bonding, following full prophylaxis. T 1 = one month following bonding. T 3 = two months following bonding Streptococcus mutans and lactobacilli will be quantified by colony count procedure. Expected results: Patients receiving orthodontic treatment experience a greater reduction in plaque buildup attributable to the synergistic effects of rajat bhasma and different mouthrinses. Conclusion: It is expected that, Rajat bhasma and triphala being ayurvedic products cause no harm and show plaque reduction. Trial number: CTRI/2022/07/044130

Pathogen-induced dormancy in liquid limits gastrointestinal colonization of Caenorhabditis elegans

ABSTRACT Colonization is generally considered a prerequisite for infection, but this event is context-dependent, as evidenced by the differing ability of the human pathogen Pseudomonas aeruginosa to efficiently colonize Caenorhabditis elegans on agar but not in liquid . In this study, we examined the impact of the environment, pathogen, host, and their interactions on host colonization. We found that the transition to a liquid environment reduces food uptake by about two-fold. Also expression of specific adhesins was significantly altered in liquid-based assays for P. aeruginosa, suggesting that it may be one factor driving diminished colonization. Unexpectedly, host immune pathways did not appear to play a significant role in decreased colonization in liquid. Although knocking down key immune pathways (e.g. daf-16 or zip-2), either alone or in combination, significantly reduced survival, the changes in colonization were very small. In spite of the limited bacterial accumulation in the liquid setting, pathogenic colonization was still required for the virulence of Enterococcus faecalis. In addition, we found that a pathogen-induced dormancy was displayed by C. elegans in liquid medium after pathogen exposure, resulting in cessation of pharyngeal pumping and a decrease in bacterial intake. We conclude that poor colonization in liquid is likely due to a combination of environmental factors and host-pathogen interactions. These results provide new insights into mechanisms for colonization in different models, enabling pathogenesis models to be fine-tuned to more accurately represent the conditions seen in human infections so that new tools for curbing bacterial and fungal infections can be developed.

Recent Advances on Electrospun Nanofibers for Periodontal Regeneration.

Periodontitis is an inflammatory infection caused by bacterial plaque accumulation that affects the periodontal tissues. Current treatments lack bioactive signals to induce tissue repair and coordinated regeneration of the periodontium, thus alternative strategies are needed to improve clinical outcomes. Electrospun nanofibers present high porosity and surface area and are able to mimic the natural extracellular matrix, which modulates cell attachment, migration, proliferation, and differentiation. Recently, several electrospun nanofibrous membranes have been fabricated with antibacterial, anti-inflammatory, and osteogenic properties, showing promising results for periodontal regeneration. Thus, this review aims to provide an overview of the current state of the art of these nanofibrous scaffolds in periodontal regeneration strategies. First, we describe the periodontal tissues and periodontitis, as well as the currently available treatments. Next, periodontal tissue engineering (TE) strategies, as promising alternatives to the current treatments, are addressed. Electrospinning is briefly explained, the characteristics of electrospun nanofibrous scaffolds are highlighted, and a detailed overview of electrospun nanofibers applied to periodontal TE is provided. Finally, current limitations and possible future developments of electrospun nanofibrous scaffolds for periodontitis treatment are also discussed.

Treatment with paeoniflorin increases lifespan of Pseudomonas aeruginosa infected Caenorhabditis elegans by inhibiting bacterial accumulation in intestinal lumen and biofilm formation

Paeoniflorin is one of the important components in Paeoniaceae plants. In this study, we used Caenorhabditis elegans as a model host and Pseudomonas aeruginosa as a bacterial pathogen to investigate the possible role of paeoniflorin treatment against P. aeruginosa infection in the host and the underlying mechanisms. Posttreatment with 1.25-10mg/L paeoniflorin could significantly increase the lifespan of P. aeruginosa infected nematodes. After the infection, the P. aeruginosa colony-forming unit (CFU) and P. aeruginosa accumulation in intestinal lumen were also obviously reduced by 1.25-10mg/L paeoniflorin treatment. The beneficial effects of paeoniflorin treatment in increasing lifespan in P. aeruginosa infected nematodes and in reducing P. aeruginosa accumulation in intestinal lumen could be inhibited by RNAi of pmk-1, egl-1, and bar-1. In addition, paeoniflorin treatment suppressed the inhibition in expressions of pmk-1, egl-1, and bar-1 caused by P. aeruginosa infection in nematodes, suggesting that paeoniflorin could increase lifespan of P. aeruginosa infected nematode by activating PMK-1, EGL-1, and BAR-1. Moreover, although treatment with 1.25-10mg/L paeoniflorin did not show obvious anti-P. aeruginosa activity, the P. aeruginosa biofilm formation and expressions of related virulence genes (pelA, pelB, phzA, lasB, lasR, rhlA, and rhlC) were significantly inhibited by paeoniflorin treatment. Treatment with 1.25-10mg/L paeoniflorin could further decrease the levels of related virulence factors of pyocyanin, elastase, and rhamnolipid. In addition, 2.5-10mg/L paeoniflorin treatment could inhibit the swimming, swarming, and twitching motility of P. aeruginosa, and treatment with 2.5-10mg/L paeoniflorin reduced the cyclic-di-GMP (c-di-GMP) level. Therefore, paeoniflorin treatment has the potential to extend lifespan of P. aeruginosa infected hosts by reducing bacterial accumulation in intestinal lumen and inhibiting bacterial biofilm formation.

Structure-activity relationships of actively FhuE transported rifabutin derivatives with potent activity against Acinetobacter baumannii

Hospital-acquired infections are on the rise and represent both, a clinical and financial burden. With resistance emerging and an ever-dwindling armamentarium at hand, infections caused by Acinetobacter baumannii are particularly problematic, since these bacteria have a high level of resistance and resilience to traditional and even last-resort antibiotics. The antibiotic rifabutin was recently found to show potent in vitro and in vivo activity against extensively drug resistant A. baumannii. Building on this discovery, we report on the synthesis and activity of rifabutin analogs, with a focus on N-functionalization of the piperidine ring. The antimicrobial testing uncovered structure activity relationships (SAR) for A. baumannii that were not reflected in Staphylococcus aureus. The cellular activity did not correlate with cell-free transcription inhibition, but with bacterial intracellular compound accumulation. Mass spectrometry-based accumulation studies confirmed the involvement of the siderophore receptor FhuE in active compound translocation at low concentrations, and they showed a strong impact of the culture medium on the accumulation of rifabutin. Overall, the study underlines the structural feature required for strong accumulation of rifabutin in A. baumannii and identifies analogs as or more potent than rifabutin against A. baumannii.

Cover Image

EcosphereVolume 14, Issue 3 e4119 COVER IMAGEOpen Access Cover Image First published: 06 March 2023 https://doi.org/10.1002/ecs2.4119AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract COVER PHOTO: Adélie penguins (Pygoscelis adeliae) have life histories dependent on suitable sea ice, landscape, seascape, and preyscape conditions—making them a valuable indicator of climate change and variability. Long-term patterns in ecosystem phenology were investigated from the perspective of Adélie penguins using data from the Palmer Antarctica Long Term Ecological Research (LTER) program. Cimino et al. (Ecosphere, Volume 14, Issue 2, Article e4417; doi: 10.1002/ecs2.4417) show that sea ice retreat and increasing photoperiod in the spring trigger a sequence of events from late spring into summer, including Adélie penguin clutch initiation, snow melt, calm weather, phytoplankton blooms, particulate organic carbon flux, peak whale abundances, and bacterial accumulation. Later sea ice retreat generally resulted in events happening later and the ecosystem was more “predictable” than early retreat years. The timing of the Adélie penguins breeding cycle was relatively consistent compared to other events, making them susceptible to mismatches in optimal environmental windows or prey characteristics that could ultimately influence chick survival. Photo credit: Darren Roberts Volume14, Issue3March 2023e4119 RelatedInformation

Effects of reducing excess dental adhesive on bacterial adhesion in the bracket periphery

ObjectivesWhite spot lesions are one of the most common side effects of orthodontic therapy with a multibracket appliance and may indicate a preliminary stage of caries, also known as initial caries. Several approaches may be utilized to prevent these lesions, such as reducing bacterial adhesion in the area surrounding the bracket. This bacterial colonization can be adversely affected by a number of local characteristics. In this context, the effects of excess dental adhesive in the bracket periphery were investigated by comparing a conventional bracket system with the APC flash-free bracket system.Materials and methodsBoth bracket systems were applied to 24 extracted human premolars, and bacterial adhesion with Streptoccocus sobrinus (S. sobrinus) was performed for 24 h, 48 h, 7 d, and 14 d. After incubation, bacterial colonization was examined in specific areas by electron microscopy.ResultsOverall, significantly fewer bacterial colonies were found in the adhesive area around the APC flash-free brackets (n = 507 ± 13 bacteria) than the conventionally bonded bracket systems (n = 850 ± 56 bacteria). This is a significant difference (**p = 0.004). However, APC flash-free brackets tend to create marginal gaps with more bacterial adhesion in this area than conventional bracket systems (n = 265 ± 31 bacteria). This bacterial accumulation in the marginal-gap area is also significant (*p = 0.029).ConclusionA smooth adhesive surface with minimal adhesive excess is beneficial for reducing bacterial adhesion but also poses a risk of marginal gap formation with subsequent bacterial colonization, which can potentially trigger carious lesions.Clinical relevanceTo reduce bacterial adhesion, the APC flash-free bracket adhesive system with low adhesive excess might be beneficial.APC flash-free brackets reduce the bacterial colonization in the bracket environment.A lower number of bacteria can minimize white spot lesions in the bracket environment.APC flash-free brackets tend to form marginal gaps between the bracket adhesive and the tooth.

Influence of Gutta-Percha Surface on Enterococcus faecalis Initial Adhesion In Vitro: An Atomic Force Microscopy Study.

The aim of this study was to evaluate the influence of surface topography of gutta-percha (GP) cones and plasticized disks of GP on the initial adhesion of Enterococcus faecalis (E. faecalis). The GP cones (Tanari and Dentsply brands) were cut 3 mm from the apical portion and fixed on a glass slide. To make the disks, the cones were thermoplasticized in standardized molds. The specimens were divided into groups according to the shape of the GP and the presence or absence of the bacteria. For contamination, the strain of E. faecalis (ATCC 29212) was used. The surface topography was analyzed using an atomic force microscope (AFM). The surface, roughness, and waviness parameters were evaluated by the Kruskal-Wallis and Dunn test. The comparison between disks and cones showed significant differences, where the cones were rougher, with a higher value attributed to the Dentsply cone (DC group). The same was observed for the waviness. After contamination, there was greater bacterial accumulation in cones, especially in their valleys, but both the surface and the topography became more homogeneous and smoother, with no differences between disks and cones of both brands. The topographic surface of the GP, at the micro and nanoscale, influences the initial adhesion of E. faecalis, with a greater tendency for contamination in regions associated with the presence of roughness and waviness. In this context, plasticization of GP is indicated, as it reduces surface irregularities compared to cones, contributing to less retention of bacteria.

Long‐term patterns in ecosystem phenology near Palmer Station, Antarctica, from the perspective of the Adélie penguin

AbstractClimate change is leading to phenological shifts across a wide range of species globally. Polar oceans are hotspots of rapid climate change where sea ice dynamics structure ecosystems and organismal life cycles are attuned to ice seasonality. To anticipate climate change impacts on populations and ecosystem services, it is critical to understand ecosystem phenology to determine species activity patterns, optimal environmental windows for processes like reproduction, and the ramifications of ecological mismatches. Since 1991, the Palmer Antarctica Long‐Term Ecological Research (LTER) program has monitored seasonal dynamics near Palmer Station. Here, we review the species that occupy this region as year‐round residents, seasonal breeders, or periodic visitors. We show that sea ice retreat and increasing photoperiod in the spring trigger a sequence of events from mid‐November to mid‐February, including Adélie penguin clutch initiation, snow melt, calm conditions (low winds and warm air/sea temperature), phytoplankton blooms, shallow mixed layer depths, particulate organic carbon flux, peak humpback whale abundances, nutrient drawdown, and bacterial accumulation. Subsequently, from May to June, snow accumulates, zooplankton indicator species appear, and sea ice advances. The standard deviation in the timing of most events ranged from ~20 to 45 days, which was striking compared with Adélie penguin clutch initiation that varied <1 week. In general, during late sea ice retreat years, events happened later (~5 to >30 days) than mean dates and the variability in timing was low (<20%) compared with early ice retreat years. Statistical models showed the timing of some events were informative predictors (but not sole drivers) of other events. From an Adélie penguin perspective, earlier sea ice retreat and shifts in the timing of suitable conditions or prey characteristics could lead to mismatches, or asynchronies, that ultimately influence chick survival via their mass at fledging. However, more work is needed to understand how phenological shifts affect chick thermoregulatory costs and the abundance, availability, and energy content of key prey species, which support chick growth and survival. While we did not detect many long‐term phenological trends, we expect that when sea ice trends become significant within our LTER time series, phenological trends and negative effects from ecological mismatches will follow.

The antidiabetic drug metformin aids bacteria in hijacking vitamin B12 from the environment through RcdA

Years of use of the antidiabetic drug metformin has long been associated with the risk of vitamin B12 (B12) deficiency in type 2 diabetes (T2D) patients, although the underlying mechanisms are unclear. Accumulating evidence has shown that metformin may exert beneficial effects by altering the metabolism of the gut microbiota, but whether it induces human B12 deficiency via modulation of bacterial activity remains poorly understood. Here, we show that both metformin and the other biguanide drug phenformin markedly elevate the accumulation of B12 in E. coli. By functional and genomic analysis, we demonstrate that both biguanides can significantly increase the expression of B12 transporter genes, and depletions of vital ones, such as tonB, nearly completely abolish the drugs’ effect on bacterial B12 accumulation. Via high-throughput screens in E. coli and C. elegans, we reveal that the TetR-type transcription factor RcdA is required for biguanide-mediated promotion of B12 accumulation and the expressions of B12 transporter genes in bacteria. Together, our study unveils that the antidiabetic drug metformin helps bacteria gather B12 from the environment by increasing the expressions of B12 transporter genes in an RcdA-dependent manner, which may theoretically reduce the B12 supply to T2D patients taking the drug over time.

Application of loofah and insects in a bio-trickling filter to relieve clogging

Bio-trickling filters (BTFs) use an inert filler to purify pollutants making them prone to clogging due to bacterial accumulation. To investigate the performance of a non-inert filler in BTF and its cooperation with insects to relieve clogging, a vertical BTF was constructed with a loofah/Pall ring/polydimethylsiloxane composite filler and selected bacteria to purify toluene. The BTF was started up within 17 d and restarted within 3 d after starvation for 12–16 d. Its average removal efficiency was >90% at steady state. The maximum elimination capacity of 86.4 g·(m3·h)−1 was obtained at a volume capacity of 96.2 g·(m3·h)−1. The introduction of holometabolous insects (Clogmia albipunctata) rapidly removed the biofilm and accelerated the degradation of the loofah, which alleviated clogging. Furthermore, confocal laser scanning microscope (CLSM) observations showed that the biofilm polysaccharides were difficult to remove, while lipids were readily lost. Analysis of microbial diversity over time and space revealed that the dominant bacterium, Comamonas, was replaced by diverse microflora with no obvious dominant genus. Insect introduction and loofah migration had little effect on the evolution of microflora. This study provides a promising approach to operating BTFs with less clogging.

Biogeochemical properties of blue carbon sediments influence the distribution and monomer composition of bacterial polyhydroxyalkanoates (PHA)

Coastal wetlands are highly efficient ‘blue carbon’ sinks which contribute to mitigating climate change through the long-term removal of atmospheric CO2 and capture of carbon (C). Microorganisms are integral to C sequestration in blue carbon sediments and face a myriad of natural and anthropogenic pressures yet their adaptive responses are poorly understood. One such response in bacteria is the alteration of biomass lipids, specifically through the accumulation of polyhydroxyalkanoates (PHAs) and alteration of membrane phospholipid fatty acids (PLFA). PHAs are highly reduced bacterial storage polymers that increase bacterial fitness in changing environments. In this study, we investigated the distribution of microbial PHA, PLFA profiles, community structure and response to changes in sediment geochemistry along an elevation gradient from intertidal to vegetated supratidal sediments. We found highest PHA accumulation, monomer diversity and expression of lipid stress indices in elevated and vegetated sediments where C, nitrogen (N), PAH and heavy metals increased, and pH was significantly lower. This was accompanied by a reduction in bacterial diversity and a shift to higher abundances of microbial community members favouring complex C degradation. Results presented here describe a connection between bacterial PHA accumulation, membrane lipid adaptation, microbial community composition and polluted C rich sediments.Graphical Geochemical, microbiological and polyhydroxyalkanoate (PHA) gradient in a blue carbon zone.

Impaired immune response and barrier function in GSPD-1-deficient C. elegans infected with Klebsiella pneumoniae

gspd-1-RNAi knockdown Caenorhabditis elegans was used as an immune-compromised model to investigate the role of G6PD in host-pathogen interactions. A shorted lifespan, increased bacterial burden and bacterial translocation were observed in gspd-1-knockdown C. elegans infected with Klebsiella pneumoniae (KP). RNAseq revealed that the innate immune pathway, including clc-1 and tsp-1, was affected by gspd-1 knockdown. qPCR confirmed that tight junction (zoo-1, clc-1) and immune-associated genes (tsp-1) were down-regulated in gspd-1-knockdown C. elegans and following infection with KP. The down-regulation of antimicrobial effector lysozymes, including lys-1, lys-2, lys-7, lys-8, ilys-2 and ilys-3, was found in gspd-1-knockdown C. elegans infected with KP. Deletion of clc-1, tsp-1, lys-7, and daf-2 in gspd-1-knockdown C. elegans infected with KP abolished the shorten lifespan seen in the Mock control. GSPD-1 deficiency in C. elegans resulted in bacterial accumulation and lethality, possibly due to a defective immune response. These findings indicate that GSPD-1 has a protective role in microbial defense in C. elegans by preventing bacterial colonization through bacterial clearance.

Biofilm formation and Streptococcus mutans adhesion on different coated and noncoated nickel-titanium archwires: An in vitro study

Abstract Aim: The orthodontic archwires used in routine practice are coated with esthetic coatings to keep up with the aesthetic demand among patients seeking orthodontic treatment, which have been reported to increase the surface roughness (SR) of archwires and lead to an increase in bacterial and plaque accumulation. This in vitro study aims to compare the biofilm formation and bacterial adherence between esthetic coated and noncoated archwires. Material and Methods: This experimental in vitro study was conducted using three aesthetic coated and two noncoated nickel-titanium (NiTi) archwires (n = 5/group). The archwires were subjected to artificially cultured Streptococcus mutans broth followed by colony count assessment (CFU) and crystal violet staining assay to determine S. mutans adhesion and biofilm formation. Statistical analysis was performed using the SPSS software for inter-group and intra-group comparisons of CFU and biofilm formation (optical density) with one-way ANOVA with post hoc Tukey’s test and Mann–Whitney’s U test. Results: A significant difference in CFU/biofilm was observed at 3% sucrose concentration between the tested archwires (P = 0.029) and epoxy coated (Libral) archwire had higher S. mutans adhesion when compared to its noncoated counterpart (P = 0.035). The biofilm formation however showed no statistical difference between the tested archwires. Conclusion: A significant difference was noted in S. mutans adherence (CFU/biofilm) under 3% sucrose condition, with greater S. mutans adherence in epoxy coated archwire. In vivo use of aesthetic coated archwires is at a similar risk of biofilm accumulation as their noncoated counterparts.