Multistep approach to control microbial fouling of historic building materials by aerial phototrophs

The scientific multistep approach described herein is a result of two years of research into a control method against microbial fouling and biodeterioration of historic building materials by phototrophs. A series of tests were conducted to select the best antifouling agent for eliminating ‘green’ coatings and protecting surfaces against biofouling. Of the seven active compounds, two with the best penetration abilities were subjected to a photosynthetic activity inhibition test using confocal microscopy. Of the two, a quaternary ammonium salt (QAC) – didecyldimethylammonium chloride (DDAC) – was found to be the most effective. Ten biocides containing QACs at different concentrations were then tested against ‘green’ coatings on wood, brick and plaster, with the best four being selected for further research in model conditions. As a result, biocides containing >14% (v v^–1) DDAC were found to be successful antifouling agents for protecting historical materials against biodeterioration by phototrophs.     

Biodegradation of didecyldimethylammonium chloride by Pseudomonas fluorescens TN4 isolated from activated sludge

Bacteria that degrade didecyldimethylammonium chloride (DDAC) were isolated from activated sludge from a municipal sewage treatment plant by enrichment culture with DDAC as a sole carbon source. One of the isolates, Pseudomonas fluorescens TN4, degraded DDAC to produce decyldimethylamine and subsequently, dimethylamine, as the intermediates. The TN4 strain also assimilated the other quaternary ammonium compounds (QACs), alkyltrimethyl- and alkylbenzyldimethyl-ammonium salts, but not alkylpyridinium salts. TN4 was highly resistant to these QACs and degraded them by an N-dealkylation process. These data mean that there are some QAC-resistant and QAC-degrading bacteria such as TN4 in the environment.     

Rapid diagnosis of rice bakanae caused by Fusarium fujikuroi and F. proliferatum using loop‐mediated isothermal amplification assays

Rice bakanae is an important disease that causes serious rice production loss worldwide. We describe a new method for rapid diagnosis of rice bakanae caused by Fusarium fujikuroi and F. proliferatum, based on loop‐mediated isothermal amplification (LAMP) assays. After screening, primers were selected to target FusariumDNA sequences, that is, the intergenic spacer (IGS) region of the nuclear ribosomal operon and reductase‐coding region (RED1) in F. fujikuroi and F. proliferatum, respectively. Both LAMP assays efficiently amplified target genes in 70 min at 62°C. A colour change from purple to sky blue (visible to the unaided eye) was observed in the presence of the DNA of the targeted pathogens only, by adding hydroxynaphthol blue to the reaction system prior to amplification. The minimum of genomic DNA needed in the assays was 67 and 346 pg/μl for F. fujikuroi and F. proliferatum, respectively. Using the two assays described here, we successfully and rapidly diagnosed suspected diseased rice plant and seed samples collected from Jiangsu Province.     

Role of aluminum in red-to-blue color changes in <Emphasis Type="Italic">Hydrangea macrophylla</Emphasis> sepals

Red, purple, and blue sepals on selected cultivars of Hydrangea macrophylla were analyzed for their aluminum content. This content was determined to be a function of the sepal color with red sepals possessing 0–10 μg Al/g fresh sepal, purple sepals having 10–40 μg Al/g fresh sepal, and blue sepals containing greater than 40 μg Al/g fresh sepal. Accordingly, the threshold aluminum content needed to change H. macrophylla sepals from red to blue was about 40 μg Al/g fresh sepal. Higher aluminum concentrations were incorporated into the sepals, but this additional aluminum did not affect the intensity or hue of the blue color. These observations agreed with a chemical model proposing that the concentration of the blue Al³⁺-anthocyanin complex reached a maximum when a sufficient excess of aluminum was present. In addition, the visible absorbance spectra of harvested red, purple, and blue sepals were duplicated by Al³⁺ and anthocyanin (delphinidin-3-glucoside) mixtures in this model chemical system.     

Efficacy of three commercially available ballast water biocides against vegetative microalgae, dinoflagellate cysts and bacteria

One proposed solution to the problem of ballast-mediated aquatic invasions involves chemically treating ballast water to kill key target organisms. Here, we examine the efficacy of three commercially available ballast water biocides using vegetative microalgae, dinoflagellate resting cysts and bacteria as test organisms. Chemicals tested were the ballast water biocides SeaKleen^® and Peraclean^® Ocean, and the chlorine dioxide biocide Vibrex^®. Results demonstrate that the applicability of each of the three chemical biocides as a routine ballast water treatment is limited by factors such as cost, biological effectiveness and possible residual toxicity of the discharged ballast water (assessed on the basis of impact on motility of vegetative marine microalgae). Of the three biocides tested, Peraclean^® Ocean appears to hold the most potential; however its effectiveness in shipboard trials is yet to be proven. Peraclean^® Ocean was biodegradable within 2–6 weeks (initial concentration of 200 ppm), could effectively inactivate resting cysts of the marine dinoflagellates Gymnodinium catenatum, Alexandrium catenella and Protoceratium reticulatum at 400 ppm, could control bacterial growth of Escherichia coli, Staphylococcus aureus, Listeria innocua and Vibrio alginolyticus at 125–250 ppm, and could eliminate vegetative dinoflagellate cells at a concentration of 100 ppm. SeaKleen^® eliminated vegetative microalgae at 2 ppm and could control resting cysts of the dinoflagellates G. catenatum and P. reticulatum at a concentration of 6 and 10 ppm, respectively, when exposed for a period of 2 weeks. SeaKleen^® did not inactivate resting cysts of A. catenella at a concentration of 10 ppm and was found to degrade at a rate that could result in the discharge of residual toxic water into the marine environment. Together with the poor bactericidal properties of SeaKleen^® (100–200 ppm required), this may limit the use of this biocide as a routine treatment option. Vibrex^® is not a suitable ballast water treatment option due to the need for hydrochloric acid as an activator, however it was found to be the most effective against bacteria (complete inhibition at 15 ppm) indicating that onboard chlorine dioxide generators may provide an effective bacterial treatment option. The performance of these biocides was adversely influenced by a variety of factors including low water temperatures (6 °C compared to 17 °C), light versus dark conditions, and the presence of humus-rich seawater and ballast water sediments.     

A frameshift mutation in the melanophilin gene causes the dilute coat colour in rabbit (Oryctolagus cuniculus) breeds

In rabbit, the dilute locus is determined by a recessive mutated allele (d) that causes the dilution of both eumelanic and pheomelanic pigmentations. In mice, similar phenotypes are determined by mutations in the myosin VA, Rab27a and melanophilin (MLPH) genes. In this study, we investigated the rabbit MLPH gene and showed that a mutation in this gene appears responsible for the dilute coat colour in this species. Checkered Giant F1 families segregating for black and grey (diluted or blue) coat colour were first genotyped for a complex indel in intron 1 of the MLPH gene that was completely associated with the coat colour phenotype (θ = 0.00; LOD = 4.82). Then, we sequenced 6357 bp of the MLPH gene in 18 rabbits of different coat colours, including blue animals. A total of 165 polymorphisms were identified: 137 were in non‐coding regions and 28 were in coding exons. One of them was a frameshift deletion in exon 5. Genotyping the half‐sib families confirmed the complete cosegregation of this mutation with the blue coat colour. The mutation was analysed in 198 rabbits of 23 breeds. All Blue Vienna and all other blue/grey/ash rabbits in other breeds (Californian, Castor Rex, Checkered Giant, English Spot, Fairy Marburg and Fairy Pearly) were homozygous for this deletion. The identification of MLPH as the responsible gene for the dilute locus in rabbit provides a natural animal model for human Griscelli syndrome type 3 and a new mutant to study the role of this gene on pigmentation.     

Removal of residual methylene chloride from homoharringtonine by pre-treatment with ethanol

In this study, methylene chloride, which is a residual solvent in final purified homoharringtonine, was removed effectively through pre-treatment with ethanol. When the final HPLC-purified sample was concentrated using a rotary evaporator, the residual methanol easily met the ICH-specified value (3000 ppm), but methylene chloride did not meet the ICH-specified value (600 ppm). However, when the sample (methylene chloride: 10,000 ppm, methanol: 500 ppm) was concentrated through pre-treatment with 95% ethanol using a rotary evaporator, the residual methylene chloride easily met the ICH-specified value. Also, the residual ethanol (concentration > 10,000 ppm) was removed effectively below the ICH-specified value (5000 ppm) through microwave-assisted drying (microwave power: 400 W).     

Germination responses of <Emphasis Type="Italic">Erica andevalensis</Emphasis> to different chemical and physical treatments

Erica andevalensis Cabezudo & Rivera is a threatened edaphic endemic species of Andalusia (SW Spain). Under natural conditions, the plants produce a very large number of small seeds (0.3–0.4 mm) but very few seedlings survive. Different treatments (high temperature, cold pre-treatment, nitrogen salts, and gibberellic acid applications) were tested to assess germination patterns in different populations and to determinate the most favorable conditions for germination. Gibberellic acid was provided in five different concentrations from 0 to 400 ppm GA₃, while nitrogen was applied as 10 mM of either KNO₃ or NH₄NO₃. The effect of pH on germination was also tested. The species always showed a low germination rate (6.50–22%) that was not stimulated either by 1 or 4 months in dry cold pre-treatment, nitrogen application, acid pH medium, or by high temperature (80°C for 10 min); although gibberellic acid application (100–400 ppm) significantly enhanced germination. The highest percentage of germination (41.6%) was achieved with a mean germination time to start germination (t ₀) of 7.6 ± 0.54 days when the seeds were subjected to 400 ppm gibberellic acid treatment. The population origin did not have a significant effect on germination percentage.     

Rapid Diagnosis of Soya Bean Root Rot Caused by Fusarium culmorum Using a Loop‐Mediated Isothermal Amplification Assay

We report a rapid diagnosis of soya bean (Glycine max L.) root rot caused by Fusarium culmorum, using a loop‐mediated isothermal amplification (LAMP) assay. We used the CYP51C gene sequence to design LAMP assay primers specific for F. culmorum. The LAMP assay amplified the target gene efficiently in 60 min at 63°C. The sensitivity of the assay was 100 pg/μl of genomic DNA. Among the tested soya bean pathogens, a positive colour (sky blue) was only observed in the presence of F. culmorum with the addition of hydroxynaphthol blue (HNB) dye prior to amplification, whereas other species isolates showed no colour change. Suspected diseased soya bean samples collected in the field from Jiangsu, Shandong and Anhui provinces and Beijing were diagnosed successfully using the LAMP assay reported here. This study provides a new and readily available method for rapid diagnosis of soya bean root rot caused by F. culmorum.     

Positive effect of the yellow morph on female reproductive success in the flower colour polymorphic Iris lutescens (Iridaceae), a deceptive species

The deceptive Iris lutescens (Iridaceae) shows a heritable and striking flower colour polymorphism, with both yellow‐ and purple‐flowered individuals growing sympatrically. Deceptive species with flower colour polymorphism are mainly described in the family Orchidaceae and rarely found in other families. To explain the maintenance of flower colour polymorphism in I. lutescens, we investigated female reproductive success in natural populations of southern France, at both population and local scales (within populations). Female reproductive success was positively correlated with yellow morph frequency, at both the population scale and the local scale. Therefore, we failed to observe negative frequency‐dependent selection (NFDS), a mechanism commonly invoked to explain flower colour polymorphism in deceptive plant species. Flower size and local flower density could also affect female reproductive success in natural populations. Pollinator behaviour could explain the positive effect of the yellow morph, and our results suggest that flower colour polymorphism might not persist in I. lutescens, but alternative explanations not linked to pollinator behaviour are discussed. In particular, NFDS, although an appealingly simple explanation previously demonstrated in orchids, may not always contribute to maintaining flower colour polymorphism, even in deceptive species.     

The influence of silver content on antimicrobial activity and color of cotton fabrics functionalized with Ag nanoparticles

The aim of this study was to examine the antimicrobial efficiency and color changes of cotton fabrics loaded with colloidal silver nanoparticles which were synthesized without using any stabilizer. The influence of colloidal concentration and consequently, the amount of silver deposited onto the fabric surface, on antimicrobial activity against Gram-negative bacterium Escherichia coli, Gram-positive bacterium Staphylococcus aureus and fungus Candida albicans as well as laundering durability of obtained effects were studied. Although cotton fabrics loaded with silver nanoparticles from 10 ppm colloid exhibited good antimicrobial efficiency, their poor laundering durability indicated that higher concentrated colloids (50 ppm) must be applied for obtaining long-term durability. Additionally, the influence of dyeing with C.I. Direct Red 81 on antimicrobial activity of cotton fabrics loaded with silver nanoparticles as well as the influence of their presence on the color change of dyed fabrics were evaluated. Unlike color change, the antimicrobial efficiency was not affected by the order of dyeing and loading of silver nanoparticles.     

Trap colour and aggregation pheromone dose affect the catch of western flower thrips in blackberry crops

Frankliniella occidentalis causes significant damage to berry crops in Mexico. Traps may be used for monitoring or mass-trapping thrips populations. Generally, colour traps are used for monitoring thrips, but sometimes a chemical stimulus can be added to the traps. However, there is conflicting information about what colour is the most attractive and efficient for capturing F. occidentalis. In this study, we first evaluated six colours of adhesive traps for catching F. occidentalis in blackberries grown in tunnels or in an open field. Subsequently, using the most attractive trap colour, we assessed the biological activity of neryl (S)-2-methylbutanoate and (R)-lavandulyl acetate, components of the pheromone aggregation of F. occidentalis. Finally, we examined the effect of neryl (S)-2-methylbutanoate dosage rates on the number of captured thrips. We found that blue (tunnel) and yellow (open field) followed by violet traps captured a significantly greater number of F. occidentalis compared with the white, black and green traps. Our results confirm that neryl (S)-2-methylbutanoate is the only component necessary for enhancing the performance of coloured traps. Blue and yellow traps baited with 200–400 µg of neryl (S)-2-methylbutanoate increased the capture 2.5–3 times compared to unbaited traps. In all experiments, traps captured more females than males in blackberries grown in tunnels, whereas the opposite was found in blackberries cultivated in the open field. These results constitute the first step in the development of a monitoring system for F. occidentalis in soft fruit crops in Mexico.     

Combined effects of elevated CO2 concentration and Wolbachia on Hylyphantes graminicola (Araneae: Linyphiidae)

The increasing concentration of carbon dioxide in atmosphere is not only a major cause of global warming, but it also adversely affects the ecological diversity of invertebrates. This study was conducted to evaluate the effect of elevated CO₂ concentration (ambient, 400 ppm and high, 800 ppm) and Wolbachia (Wolbachia‐infected, W⁺ and Wolbachia‐uninfected, W^?) on Hylyphantes graminicola. The total survival rate, developmental duration, carapace width and length, body weight, sex ratio, net reproductive rate, nutrition content, and enzyme activity in H. graminicola were examined under four treatments: W^? 400 ppm, W^? 800 ppm, W⁺ 400 ppm, and W⁺ 800 ppm. Results showed that Wolbachia‐infected spiders had significantly decreased the total developmental duration. Different instars showed variations up to some extent, but no obvious effect was found under elevated CO₂ concentration. Total survival rate, sex ratio, and net reproductive rate were not affected by elevated CO₂ concentration or Wolbachia infection. The carapace width of Wolbachia‐uninfected spiders decreased significantly under elevated CO₂ concentration, while the width, length and weight were not significantly affected in Wolbachia‐infected spiders reared at ambient CO₂ concentration. The levels of protein, specific activities of peroxidase, and amylase were significantly increased under elevated CO₂ concentration or Wolbachia‐infected spiders, while the total amino content was only increased in Wolbachia‐infected spiders. Thus, our current finding suggested that elevated CO₂ concentration and Wolbachia enhance nutrient contents and enzyme activity of H. graminicola and decrease development duration hence explore the interactive effects of factors which were responsible for reproduction regulation, but it also gives a theoretical direction for spider's protection in such a dynamic environment. Increased activities of enzymes and nutrients caused by Wolbachia infection aids for better survival of H. graminicola under stress.     

Antimicrobial activity of AgCl embedded in a silica matrix on cotton fabric

An antimicrobial finishing for cotton fabric was prepared from commercial (iSys AG, Germany) silver chloride (Ag) dispersed at different concentrations in a reactive organic–inorganic binder (RB) (iSys MTX (CHT, Germany). Pad-dry-cure and exhaustion methods were used for the sols application, giving Ag-RB coating with Ag concentration from ca. 48 to ca. 290 ppm on the cotton fabric. The presence of silver on the cotton finishes was confirmed by measuring its concentration in the fabrics with the help of inductively coupled plasma mass spectroscopy (ICP-MS). The morphology of the finished fabrics was investigated by SEM, while their composition was established from EDXS measurements combined with the results of FT-IR spectral analysis. The antimicrobial activity of variously treated cotton fabrics was assessed before and after repetitive (up to 10×) washing by the application of standard tests: for the fungi Aspergillus niger (ATCC 6275) and Chaetomium globosum (ATCC 6205) by the modified DIN 53931 standard method, while the presence of Gram-negative bacterium Escherichia coli (ATCC 25922) was followed by using ISO 20645:2004 (E) and AATCC 100-1999 standard methods. Results revealed that the antimicrobial activity of the coatings strongly depended on the concentration of Ag in the corresponding Ag-RB dispersions, indirectly depending on the preparation method (pad-dry-cure vs. exhaustion) and that the Ag-RB coatings were more effective for bacteria than for fungi. The Ag concentrations on the cotton fabrics achieved by the pad-dry-cure method (48 and 52 ppm) were not sufficient to impart satisfactory antifungal activity to the cotton fabrics, though they assured excellent reduction of the bacterium E. coli (98–100%). A minimal inhibitory concentration of Ag in the coating providing a sufficient bacterial reduction of 60% was ca. 24 ppm. Effective antifungal activity was achieved only by applying the exhaustion method, enabling high initial Ag concentration in the Ag-RB coating (>100 ppm). The antibacterial activity depended on the washing treatment. No antifungal activity was noted for washed cotton fabric, even those with highly concentrated Ag (290 ppm) in the Ag-RB coating, but a 94% bacterial reduction was obtained for the corresponding cotton fabric, after 10 repetitive washings, corroborated by the Ag concentration on washed fabric of about 65 ppm.     

In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

Background  

The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16) strain in two mouse wound models.     

Lindernia kinmenensis sp. nov. (Scrophulariaceae) from Kinmen (Taiwan)

Lindernia kinmenensis Y. S. Liang, C. H. Chen, & C. L. Tasi sp. nov. from Kinmen (Taiwan) is described. The new species belongs to section Torenioides and is most similar to L. crustacea. It differs from the latter by the following characters: calyx pubescent between the ridges (vs pubescent on ridges), with (2)3(4) bristles on the ridge near the apex of the calyx‐lobes (vs without such bristles), corolla shorter, 6–8 mm long (vs 7–11 mm long) and pale purple (vs purple or blue), posterior theca with obtuse (vs acute) apex. This species is usually found in sandy wetlands. A line drawing, colour photos and SEM micrographs of pollen and seed as aids for identification are provided.     

Structural colour in the moss Sphagnum subnitens Russ. & Warnst

Abstract

The blue-grey sheen of dried specimens of Sphagnum subnitens is attributed to thin film interference in the walls of the hyaline cells, this being produced by reflection from upper and lower film surfaces. The reflectance is large in air and small in water, so that the colour is visible only in dried specimens. S. rubellurn lacks the blue-grey sheen because only a small part of the total area of the hyaline cells is thin enough to generate interference colour.     

Use of plant products and copepods for control of the dengue vector, <Emphasis Type="Italic">Aedes aegypti</Emphasis>

The efficacy of plant extracts (neem tree, Azadirachta indica A. Juss.; Meliaceae) and copepods [Mesocyclops aspericornis (Daday)] for the control of the dengue vector Aedes aegypti L. was tested in the laboratory. Neem Seed Kernel Extract (NSKE) at 25, 50, 100, 200 and 400 ppm caused significant mortality of Ae. aegypti larvae. Lethal concentrations (LC₅₀ and LC₉₀) were worked out. The LC₅₀ and LC₉₀ values for I to IV larval instars were 111.98, 138.34, 158.93, 185.22 ppm and for pupae was 146.13 ppm, respectively. The LC₉₀ value of I instar was 372.95 ppm, II instar was 422.77 ppm, III instar was 440.63 ppm, IV instar was 456.96 ppm, and pupae was 476.92 ppm, respectively. A study was conducted to test the whether the predatory efficiency of copepods on first instars changed in the presence of NSKE. The percentage of predatory efficiency of copepod was 6.80% in treatments without NSKE and the percentage of predatory efficiency increased up to 8.40% when copepods were combined with NSKE. This increase in predation efficiency may caused by detrimental effects of the neem active principle compound (Azadirachtin) on the mosquito larvae. Our results suggest that the combined application of copepods and neem extract to control Aedes populations is feasible. Repeated application of neem does not cause changes in copepod populations, because neem is highly degradable in the environment.