Microstructural and physicochemical quality maintenance in green bell pepper infected with Botrytis cinerea and treated with thyme essential oil combined with carnauba wax

Bell pepper presents rapid weight loss and is highly susceptible to gray mold caused by the fungus Botrytis cinerea. The most employed method to control this disease is the application of synthetic fungicides such as thiabendazole (TBZ); however, its continued use causes resistance in fungi as well as environmental problems. For these reasons, natural alternatives arise as a more striking option. Currently, bell pepper fruits are coated with carnauba wax (CW) to prevent weight loss and improve appearance. Moreover, CW can be used as a carrier to incorporate essential oils, and previous studies have shown that thyme essential oil (TEO) is highly effective against B. cinerea. Therefore, this study aimed to evaluate the effect of CW combined with TEO on the development of gray mold and maintenance of microestructural and postharvest quality in bell pepper stored at 13°C. The minimal inhibitory concentration of TEO was 0.5%. TEO and TBZ provoked the leakage of intracellular components. TEO and CW + TEO treatments were equally effective to inhibit the development of gray mold. On the quality parameters, firmness and weight loss were ameliorated with CW and CW + TEO treatments; whereas lightness increased in these treatments. The structural analysis showed that CW + TEO treatment maintained the cell structure reducing the apparition of deformities. The results suggest that CW + TEO treatment could be used as a natural and effective antifungal retarding the appearance of gray mold and maintaining the postharvest quality of bell pepper. PRACTICAL APPLICATION: CW and TEO are classified as generally recognized as safe (GRAS) by the US Food and Drug Administration (FDA). This combination can be employed on the bell pepper packaging system to extend shelf life and oppose gray mold developments. Bell pepper fruits are normally coated with lipid-base coatings such as CW before commercialization; therefore, TEO addition would represent a small investment without any changes on the packaging system infrastructure.

A novel cultivation platform of duckweed (Lemna minor) via application of beeswax superhydrophobic coatings

Conventional establishment of laboratory cultures of duckweed Lemna minor are prepared in beakers, Erlenmeyer flasks or Schott bottles. These conventional cultivation methods limit the available surface area for growth which then causes layering of fronds that reduces the efficiency of plants in sunlight capturing. Here, acrylic sheets were spray-coated with a superhydrophobic (SHP) beeswax suspension and these coated acrylic sheets were used as a novel cultivation platform for L. minor. L. minor was grown for 7 days in conventional glass jar which acted as the control and were compared to SHP coated acrylic (SHPA) and SHP coated acrylic with aluminium mesh centrally placed (SHPAM) at similar duration and cultivation conditions. Addition of mesh was to entrap the plantlets and fixed the plantlets' position on the growing platform. The effects of cultivation platforms on growth rate and biochemical compositions of L. minor were monitored. The highest biomass growth was obtained from SHPA cultivation where the relative growth rate (RGR) was 0.0909 ± 0.014 day^-1 and the RGR was 2.17 times higher than the control. Moreover, L. minor harvested from SHPA displayed the highest values in total protein content, total carbohydrates content and crude lipid percentage. The values were 156.04 ± 12.13 mg/g, 94.75 ± 9.02 mg/g and 7.09 ± 1.14% respectively. However, the control showed the highest total chlorophyll content which was 0.7733 ± 0.042 mg/g FW. Although SHPA obtained a slightly lower chlorophyll content than the control, this growing platform is still promising as it displayed the highest growth rate as well as other biochemical composition. Hence, this study proved that the proposed method that applied superhydrophobic properties in cultivation of L. minor provided a larger surface area for L. minor to grow, which then resulted in a greater biomass production while simultaneously maintaining the quality of the biochemical compositions of duckweeds.

Biomedical Properties of Propolis on Diverse Chronic Diseases and Its Potential Applications and Health Benefits

The use of alternative medicine products has increased tremendously in recent decades and it is estimated that approximately 80% of patients globally depend on them for some part of their primary health care. Propolis is a beekeeping product widely used in alternative medicine. It is a natural resinous product that bees collect from various plants and mix with beeswax and salivary enzymes and comprises a complex mixture of compounds. Various biomedical properties of propolis have been studied and reported in infectious and non-infectious diseases. However, the pharmacological activity and chemical composition of propolis is highly variable depending on its geographical origin, so it is important to describe and study the biomedical properties of propolis from different geographic regions. A number of chronic diseases, such as diabetes, obesity, and cancer, are the leading causes of global mortality, generating significant economic losses in many countries. In this review, we focus on compiling relevant information about propolis research related to diabetes, obesity, and cancer. The study of propolis could generate both new and accessible alternatives for the treatment of various diseases and will help to effectively evaluate the safety of its use.

Chemical profiles of cuticular waxes on various organs of Sorghum bicolor and their antifungal activities

Sorghum bicolor is widely cultivated in arid and semi-arid areas. This paper reports the chemical profiles of cuticular waxes on adaxial and abaxial sides of common leaf, flag leaf, sheath and stem from six sorghum cultivars and the variations of leaf cuticular waxes at seedling, jointing and filling stages. Then, the bioassay of leaf and sheath wax were evaluated against Penicillium sp and Alternaria alternata. The six sorghum cultivars had similar wax profiles. In total, eight wax compounds were identified, including fatty acids, aldehydes, primary alcohols, alkanes, secondary alcohols, ketones, sterols and minor triterpenoids. Leaf wax coverage increased from 2.2 to 3.1 μg/cm² at seedling stages to 6.5-14.0 μg/cm² at jointing and filling stages, respectively. The relative abundance of primary alcohols decreased from 51 to 62% at seedling stage to 17-33% at jointing stage whereas alkanes increased from 5-9% to 19-33%. Leaf was dominated with alkanes (28.4%) and aldehydes (28.4%), sheath with acids (42.8%), and stem with aldehydes (80.8%). Epicuticular wax of leaf and sheath contained higher proportions of alkanes whereas the intracuticular waxes contained higher proportions of sterols. The leaf wax improved the growth of Penicillium but reduced that of A. alternaria, whereas sheath wax reduced the growth of Penicillium but unchanged A. alternaria. The detailed sorghum wax profiles improve our understanding of the physiological roles of these waxes and their diversified potential usages in industries.

Acute Effects of Transdermal Administration of Jojoba Oil on Lipid Metabolism in Mice

Background and objectives: Aroma therapy is a complementary therapy using essential oils diluted with carrier oils. Jojoba oils have been widely used as carrier oils. However, limited information is available regarding their effects on blood biochemical parameters. This study aimed to investigate the effect of transdermal administration of jojoba oil on blood biochemical parameters in mice. Materials and Methods: Eight-week-old male hairless mice were randomly divided into naïve control and treatment groups. In the treatment group, mice were topically administered 4 μL of jojoba oil, per gram of body weight, on the dorsa 30 min before euthanasia. Thereafter, serum biochemical parameters were assayed, and gene expression was analyzed in various tissues via a real-time polymerase chain reaction. Results: Serum non-esterified fatty acid (NEFA) levels increased significantly 30 min after topical application of jojoba oil (p < 0.05). Atgl was significantly upregulated in the liver (p < 0.05), and Atgl upregulation in the liver was positively correlated with serum NEFA levels (r = 0.592, p < 0.05). Furthermore, a trend of decreasing fatty acid trafficking-related gene (FABPpm, FATP-1, FATP-3, and FATP-4) expression in the skin after topical application of jojoba oil (p = 0.067, 0.074, 0.076, and 0.082, respectively) was observed. Conclusions: Serum NEFA levels were elevated 30 min after transdermal administration of jojoba oil. The mechanisms of elevated serum NEFA levels might be related to both enhanced lipolysis in the liver and reduced fatty acid trafficking in the skin.

Klein-Nishina electronic cross-section, Compton cross sections, and buildup factor of wax for radiation shielding and protection

Klein-Nishina scattering cross-sections, Compton scattering, mass attenuation and energy transfer cross-sections, linear attenuation coefficient and buildup factor of 99.99% pure paraffin wax (Carbon = 85.14%, Hydrogen = 14.86%). are calculated using 0.662, 0.835, 1.17 and 1.33 MeV γ-rays. The mentioned γ-rays were obtained from Cs-137, Mn-54 and Co-60 radioisotopes. Gamma rays obtained from these radioisotopes were passed through circular shaped wax slices and allowed to fall on a NaI detector. The thickness of wax slices were 0.33-2.9 cm with 6 cm diameter. Lead collimator of 1 cm diameter hole in the middle was used to obtain a collimated beam for narrow beam geometry. Broad beam geometry was used by removing the collimator to investigate buildup factor. Results show that Klein-Nishina electronic cross-section, Compton mass attenuation coefficient and Compton energy transfer coefficient all decrease with increasing photon energy. Linear attenuation coefficients μ = 0.0532 cm^-1 for 1.17 MeV beam and μ = 0.0419 cm^-1 for 1.33 MeV γ-rays were obtained for wax. Variations in buildup factors are observed with increasing thickness of wax for 1.17 and 1.33 MeV beams.

Hypolipidemic activity of P-methoxycinnamic diester (PCO-C) isolated from Copernicia prunífera against Triton WR-1339 and hyperlipidemic diet in mice

Carnauba wax is extracted from the leaves of the Copernicia prunífera and contains approximately 80% of esters in its composition. The purpose of the present study was evaluate the hypolipidemic effect of p-methoxycinnamic diesters (PCO-C) extracted from Copernicia prunífera in a model of acute and chronic dyslipidemia in mice. The levels of total cholesterol and triglycerides were significantly reduced plasma levels in PCO-C at the dose of 100mg/kg in a model of acute and chronic dyslipidemia. Histological studies showed that PCO-C has no hepatotoxic effect and reduces hepatic steatosis in animals that consumed hyperlipidemic ration. Thus, it was concluded that PCO-C isolated from Copernicia Prunifera was effective in reducing total cholesterol and triglyceride levels in both dyslipidemia induction models. The finding indicates that PCO-C might be beneficial in treatment of hyperlipidemia and atherosclerosis.

Spruce budworm feeding and oviposition are stimulated by monoterpenes in white spruce epicuticular waxes

Monoterpenes, source of the distinctive odor of conifers, are generally considered plant defensive compounds. However, they are also known to act as long-range insect attractants, as they are volatile and permeate forest airspaces. Moreover, they are lipid soluble and can be absorbed into plant epicuticular waxes. We test their role in short-range host plant choice by both adult females and larvae of a folivorous forest pest (Choristoneura fumiferana). We conducted laboratory assays testing the responses of Eastern spruce budworm to an artificial monoterpene mix (α-pinene, β-pinene, limonene, myrcene) and to white spruce (Picea glauca) epicuticular waxes in closed arenas. Ovipositing females preferred filter paper discs treated with P. glauca waxes to controls, and preferred the waxes + monoterpenes treatment to waxes alone. However, females showed no preference between the monoterpene-treated disc and the control when presented without waxes. Feeding larvae prefered wax discs to control discs. They also consumed discs treated with realistic monoterpene concentrations and wax preferentially over wax-only discs, but showed no preference between extremely high monoterpene concentrations and wax-only controls. In an insect-free assay, P. glauca epicuticular wax decreased monoterpene volatilization. These results suggest that P. glauca waxes and realistic concentrations of monoterpenes are stimulatory to both egg-laying females and feeding larvae, and that their effects are synergistic.

Antiprotozoal activity of extracts and isolated triterpenoids of 'carnauba' (Copernicia prunifera) wax from Brazil

CONTEXT

'Carnauba' wax is a natural product obtained from the processing of the powder exuded from Copernicia prunifera (Miller) H. E. Moore (Arecaceae). This material is widely used in the Brazilian folk medicine, including the treatment of rheumatism and syphilis.

OBJECTIVE

To investigate the antiprotozoal activity of hexane and EtOH extracts from the 'carnauba' wax as well as from the isolated compounds from the bioactive extracts.

MATERIAL AND METHODS

Two different samples of 'carnauba' (C. prunifera) waxes - types 1 and 4 - were individually extracted using hexane (EH) and EtOH (EE). Aliquots of hexane (type 1 - EH-1 and EH-4) and EtOH (type 4 - EE-1 and EE-4) extracts were tested against promastigote (2-200 μg/mL in DMSO during 48 h at 24 °C) and amastigote (3-150 μg/mL in DMSO during 120 h at 37 °C) forms of Leishmania infantum as well as against trypomastigote (3-150 μg/mL in DMSO during 24 h at 37 °C) forms of Trypanosoma cruzi. Bioactive extracts EH-1 and EE-4 were subjected to a bioactivity-guided fractionation to afford three dammarane-type triterpenoids (1-3). The in vitro antiprotozoal activities of the obtained compounds were evaluated as described above. Additionally, the cytotoxicity activity of compounds 1-3 against mammalian conjunctive cells (NCTC - 2-200 μg/mL in DMSO during 48 h at 37 °C) was determined.

RESULTS

From the bioactive hexane and EtOH extracts from the 'carnauba' (C. prunifera) wax, were isolated three dammarane-type triterpenoids: (24R*)-methyldammar-25-ene-3β,20-diol (carnaubadiol, 1), (24R*)-methyldammara-20,25-dien-3-one (2) and (24R*)-methyldammara-20,25-dien-3α-ol (3). These compounds were identified based on the analysis of NMR and MS spectroscopic data. Compounds 1-3 were effective against the intracellular amastigotes of L. infantum, with IC₅₀ values ranging from 8 to 52 μM, while compounds 1 and 3 displayed activity against trypomastigote forms of T. cruzi with IC₅₀ values of 15 and 35 μM, respectively. The mammalian cytotoxicity assay demonstrated no damage to NCTC conjunctive cells up to 200 μM, except for compound 1, which demonstrated a CC₅₀ value of 34 μM.

CONCLUSION

Based on the results, it was possible to conclude that the detected antiprotozoal bioactivity of 'carnauba' (C. prunifera) wax extracts could be related to the presence of the natural dammarane triterpenoid derivatives. The results suggested that these compounds could be used as promising scaffolds for drug design studies for leishmaniasis and Chagas disease.

Insecticidal Properties of a Highly Potent Wax Isolated from Dolichandra cynanchoides Cham

Bioassay-guided fractionation of an ethanolic extract of the aerial parts of Dolichandra cynanchoides Cham. (Bignoniaceae) led to the isolation of a natural wax with anti-insect activity against Spodoptera frugiperda (Noctuidae) and Epilachna paenulata (Coleptera). The compound was identified spectroscopically as an ester of a C27 fatty acid and a C25 alcohol, pentacosyl heptacosanoate (1). The effective doses of 1 for 50% feeding inhibition (ED50) of S. frugiperda and E. paenulata were 0.82 and 8.53 µg/cm², respectively, in a choice test, while azadirachtin showed ED50 of 0.10 and 0.59 µg/cm², respectively. In a no-choice test, both insects refused to feed on leaves treated with 1 at doses of 0.1 µg/cm² or greater inhibiting larval growth and dramatically reducing survival. The lethal doses 50 (LD50) of 1 were 0.39 and 0.68 µg/cm² for S. frugiperda and E. paenulata, respectively. These results indicate that 1 has potential for development as botanical insecticides. Similar esters might be obtainable in large quantities as many edible crops produce wax esters that are discarded during food processing. Research on these materials could lead to the detection of similar waxes with insecticidal activity.

Impact of sweet sorghum cuticular waxes (SSCW) on acetone-butanol-ethanol fermentation using Clostridium acetobutylicum ABE1201

The effect of cuticular waxes of sweet sorghum stem on acetone-butanol-ethanol (ABE) fermentation process was investigated. About 22.9% of butanol and 25.4% of ABE were decreased with fermentation period extended when SSCW was added. The inhibition of SSCW militate against both acidogenesis and solventogenesis phase, which were inconsistent with the inhibition of lignocellulose hydrolysate. Further studies on the composition of SSCW were performed. Regulations of inhibition with different carbon chain length of main compositions of SSCW on ABE fermentation were also investigated.

A new ovitrap made of slow release natural materials containing pyriproxyfen for Aedes aegypti (Diptera:Culicidae) control

ABSTRACT This initial study is aimed to measure the performance of incorporating pyriproxyfen in natural materials with low environmental impact to obtain slow release formulations that can be used as larvicidal or autocidal ovitraps avoiding hatched Aedes aegypti (L.) eggs to emerge as adults. Hollow candles made of beeswax or paraffin:stearin 1:1 mixture containing pyriproxyfen 0.01 and 0.05% were prepared and used as holding water containers for larval bioassay. Pyriproxyfen was released quickly into the larvae-breeding water. Ae. aegypti larvae were introduced immediately after the addition of tap water to the hollow candles (t = 1 min) or after 1, 4, and 8 h. More than 40% of the larvae did not emerge as adults for t = 1 min, reaching 80-100% when the larvae were added after 1 or 4 h, respectively. The hollow candles were kept at room temperature, and water was replaced every 15 d. Bioassays performed every 30 d showed that the residual activity obtained for both matrices and both concentrations of pyriproxyfen was higher than 360 d, with 100% inhibition of adult emergence.

Dual-functional beeswaxes on enhancing antimicrobial activity and water vapor barrier property of paper

The guanidine-based antimicrobial polymers were grafted onto the surface of beeswax latex particles stabilized with or without amphoteric surfactant, n-dodecyl-N,N-dimethylglycine. N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) was used as a coupling reagent to introduce the covalent bonding or ensure sufficient binding force. The resulting novel beeswax latexes were utilized as a dual-functional paper additive, which improved both water-vapor resistance and antimicrobial activities of the paper. Compared with control sample, the water vapor transmission rate of the paper was reduced significantly. The antimicrobial activity of paper against E. coli was also improved substantially even at a low dosage of the beeswax latex derivatives (20 mg/g fiber).

Antimicrobial activity in the egg wax of the tick Amblyomma hebraeum (Acari: Ixodidae) is associated with free fatty acids C16:1 and C18:2

Untreated eggs of the tick Amblyomma hebraeum Koch (Acari: Ixodidae) exhibited antimicrobial activity (AMA) against Gram-negative but not Gram-positive bacteria; eggs denuded of wax by solvent extraction showed no AMA. The unfractionated egg wax extract, however, showed AMA against Gram-positive but not Gram-negative bacteria, as also shown by Arrieta et al. (Exp Appl Acarol 39: 297-313, 2006). In this study we partitioned the egg wax into various fractions, using a variety of techniques, analyzed their compositions, and tested them for AMA. The crude aqueous extract exhibited AMA. However, although more than 30 metabolites were identified in this extract by nuclear magnetic resonance analysis, none of them seemed likely to be responsible for the observed AMA. In the crude organic extract, cholesterol esters were the most abundant lipids, but were devoid of AMA. Fatty acids (FAs), with chain lengths between C13 and C26 were the next most abundant lipids. After lipid fractionation and gas chromatography/mass spectroscopy, free FAs, especially C16:1 and C18:2, accounted for most of the AMA in the organic extract. The material responsible for AMA in the crude aqueous extract remains unidentified. No AMA was detected in the intracellular contents of untreated eggs.

Wax on, wax off: nest soil facilitates indirect transfer of recognition cues between ant nestmates

Social animals use recognition cues to discriminate between group members and non-members. These recognition cues may be conceptualized as a label, which is compared to a neural representation of acceptable cue combinations termed the template. In ants and other social insects, the label consists of a waxy layer of colony-specific hydrocarbons on the body surface. Genetic and environmental differences between colony members may confound recognition and social cohesion, so many species perform behaviors that homogenize the odor label, such as mouth-to-mouth feeding and allogrooming. Here, we test for another mechanism of cue exchange: indirect transfer of cuticular hydrocarbons via the nest material. Using a combination of chemical analysis and behavioral experiments with Camponotus aethiops ants, we show that nest soil indirectly transfers hydrocarbons between ants and affects recognition behavior. We also found evidence that olfactory cues on the nest soil influence nestmate recognition, but this effect was not observed in all colonies. These results demonstrate that cuticular hydrocarbons deposited on the nest soil are important in creating uniformity in the odor label and may also contribute to the template.

Wound healing properties of jojoba liquid wax: an in vitro study

AIM OF THE STUDY

The wound healing properties of jojoba (Simmondsia chinensis) liquid wax (JLW) were studied in vitro on HaCaT keratinocytes and human dermal fibroblasts, which are involved in wounded skin repair.

MATERIALS AND METHODS

JLW cytotoxicity was evaluated by the crystal violet staining and the neutral red uptake endpoint. Induction of wound healing by JLW was assessed by scratch wound assay on cell monolayers. The involvement of signaling pathways was evaluated by the use of the Ca(2+) chelator BAPTA and of kinase inhibitors, and by Western blot analysis of cell lysates using anti-phospho antibodies. Collagen and gelatinase secretion by cells were assayed by in-cell ELISA and zymography analysis, respectively.

RESULTS

Cytotoxicity assays showed that the toxic effects of JLW to these cells are extremely low. Scratch wound experiments showed that JLW notably accelerates the wound closure of both keratinocytes and fibroblasts. The use of inhibitors and Western blot revealed that the mechanism of action of JLW is strictly Ca(2+) dependent and requires the involvement of the PI3K-Akt-mTOR pathway and of the p38 and ERK1/2 MAPKs. In addition, JLW was found to stimulate collagen I synthesis in fibroblasts, while no effect was detected on the secretion of MMP-2 and MMP-9 gelatinases by HaCaT or fibroblasts.

CONCLUSIONS

Taken together, data provide a pharmacological characterization of JLW properties on skin cells and suggest that it could be used in the treatment of wounds in clinical settings.

Antifeedant activity of citrus waste wax and its fractions against the dry wood termite, Cryptotermes brevis

The wood protective action of citrus wax, a waste from the citrus industry that is a mixture of citrus fruit epicuticular waxes and essential oils, was evaluated against the termite Cryptotermes brevis Walker (Isoptera: Kalotermitidae). The antifeedant index (AI) of the total wax and fractions was calculated. The total citrus wax exhibited an AI₅₀ value of 24.69 mg/cm³, the wax after hydrodistillation showed the strongest antifeedant property (AI₅₀ 11.68 mg/cm³). Fractionation of the wax and gas chromatography-mass spectrometric analysis allowed the identification of coumarins and furancoumarins as the active compounds. These results suggest the potential use of these industrial residues as a natural approach to termite control.

Vehicle and enhancer effects on human skin penetration of aminophylline from cream formulations: evaluation in vivo

The effects of four essential oils (rosemary, ylang, lilacin, and peppermint oils), and three plant oils (jojoba oil, corn germ oil, and olive oil) on the permeation of aminophylline were studied using human skin. The permeation effects of these oils were compared with those of three chemical penetration enhancers. Although all oils enhanced the permeation of aminophylline, their effects were less than that of ethanol. Jojoba oil was found to be the most active, causing about a 32% peak height decrease of N-H bending absorbances in comparison with the control, while peppermint, lilacin, rosemary, and ylang oils caused 28%, 24%, 18%, and 12% peak height decreases, respectively. Microemulsions containing 10% jojoba oil and 30% corn germ oil were found to be superior vehicles for the percutaneous absorption of aminophylline. Comparision with results obtained from high-performance liquid chromatography shows good agreement.

The Effects of Hemostatic Agents on Peripheral Nerve Function: An Experimental Study

PURPOSE

In the practice of oral and maxillofacial surgery, hemostatic agents are sometimes placed in close proximity to peripheral nerves. In the present study, we evaluated immediate and delayed effects of 4 hemostatic agents (oxidized regenerated cellulose, 5% colloid silver-added gelatine sponge, bovine collagen, bone wax) on peripheral nerve function.

MATERIALS AND METHODS

A total of 25 rat sciatic nerves were prepared, and the amplitudes were recorded with a physiological data acquisition system. Animals were randomly assigned to 5 groups: control, oxidized regenerated cellulose, gelatine sponge, bone wax, and bovine collagen. The first hour records are defined as immediate effects of these hemostatic agents on nerve function. The animals were then allowed to recover for 4 weeks. At the end of this period, the same surgical and recording procedures were performed. These final records are defined as delayed effects of hemostatic agents on nerve function. According to nerve conduction velocity (NCV) and compound action potential (CAP) values of the experimental groups, early and delayed effects of each hemostatic agent were statistically compared with Bonferroni corrected test (P < .05).

RESULTS

Statistically, NCV was significantly reduced, and the CAP was significantly increased 1 hour after surgery (P < .05) in the group of oxidized regenerated cellulose. However, there were no significant differences after 4 weeks compared with the first records. In the gelatine sponge group, CAP was significantly increased 4 weeks after the application. In the bovine collagen and bone wax groups, NCV and CAP values (1 hour and 4 weeks after the application) were not statistically significant compared with initial control records.

CONCLUSION

The present study shows that bovine collagen is the most suitable hemostatic agent applicable for peripheral nerves.

Effects of Nidus Vespae extract and chemical fractions on glucosyltransferases, adherence and biofilm formation of Streptococcus mutans

Nidus Vespae (the honeycomb of Polistes olivaceous, P. japonicus Saussure and Parapolybiavaria fabricius) have been extensively used in traditional Chinese medicine, given their multiple pharmacological activities, including antimicrobial, anti-inflammatory, anti-virus, anti-tumor and anesthetic properties. The present study evaluated the anti-glucosyltransferases (GTFs) activity, anti-adherence and anti-biofilm properties of 95% ethanol/water extract, cyclohexane/ethyl acetate, petroleum ether/ethyl acetate and chloroform/methanol fractions of Nidus Vespae. Chloroform/methanol fraction showed a remarkable capacity for inhibiting the adherence of Streptococcus mutans ATCC 25175 to saliva-coated hydroxyapatite disc (S-HA) at sub-MC concentrations. In addition, the Nidus Vespae extract and chemical fractions significantly inhibited the activity of cell-associated and extracellular GTFs at sub-MIC concentrations, and the chloroform/methanol fraction was the most effective one. For the anti-biofilm activity assays, minimum biofilm inhibition concentrations (MBIC50) and minimum biofilm reduction concentrations (MBRC50) were determined using the microdilution method. The chloroform/methanol fraction showed the highest anti-biofilm activities with a MBIC50 of 8mg/ml and a MBRC(50) of 16mg/ml against Streptococcus mutans ATCC 25175. The significant inhibition of GTFs activity and biofilm formation demonstrated by Nidus Vespae shows it to be a promising natural product for the prevention of dental caries.

An in vivo model to evaluate the efficacy of barrier creams on the level of skin penetration of chemicals

The reservoir function and the barrier function are important properties of the skin. The reservoir function is dependent on the barrier function which, however, needs support by protective measures, in particular under working conditions. Barrier creams represent a possibility to protect the skin. In the present study, a method was developed to investigate the effectiveness of reservoir closure by different formulations. Patent Blue V in water was used as a model penetrant. Its penetration, with and without barrier cream treatment, was analyzed by tape stripping in combination with UV/VIS spectroscopic measurements. The investigations showed that the stratum corneum represents a reservoir for topically applied Patent Blue V in water. Furthermore, the barrier investigations showed that vaseline and bees wax form a 100% barrier on the skin surface. The third barrier cream, containing waxes and surfactant, only partially showed a protective effect against the penetration of Patent Blue V in water. Strong interindividual differences were observed for this barrier product. In conclusion, it was assumed that the application of barrier creams cannot replace other protective measures and should be maximally used to inhibit low-grade irritants or in combination with other protectants or in body areas where other protective measures are not applicable.

The safety and efficacy of a mixture of honey, olive oil, and beeswax for the management of hemorrhoids and anal fissure: a pilot study

We have found that a mixture of honey, olive oil, and beeswax was effective for treatment of diaper dermatitis, psoriasis, eczema, and skin fungal infection. The mixture has antibacterial properties. A prospective pilot study was conducted to evaluate the therapeutic effect of topical application of the mixture on patients with anal fissure or hemorrhoids.Fifteen consecutive patients, 13 males and 2 females, median age 45 years (range: 28—70), who presented with anal fissure (5 patients) or first- to third-degree hemorrhoids (4 with first degree, 4 with second degree, and 2 with third degree), were treated with a 12-h application of a natural mixture containing honey, olive oil, and beeswax in ratio of 1:1:1(v/v/v). Bleeding, itching, edema, and erythema were measured using a scoring method: 0 = none, 1 = mild, 2 = moderate, 3 = severe, and 4 = very severe. The pain score was checked using a visual analog scale (minimum = 0, maximum = 10). Efficacy of treatment was assessed by comparing the symptoms' score before and after treatment; at weekly intervals for a maximum of 4 weeks. The patients were observed for evidence of any adverse effect such as appearance of new signs and symptoms, or worsening of the existing symptoms. The honey mixture significantly reduced bleeding and relieved itching in patients with hemorrhoids. Patients with anal fissure showed significant reduction in pain, bleeding, and itching after the treatment. No side effect was reported with use of the mixture. We conclude that a mixture of honey, olive oil, and beeswax is safe and clinically effective in the treatment of hemorrhoids and anal fissure, which paves the way for further randomized double blind studies.

Polymethylmethacrylate causes prolonged pulmonary hypertension during fat embolism: a study in sheep

BACKGROUND

Fat embolism (FE), the release of bone marrow contents into the circulation and the subsequent cardiovascular changes, is still a potentially fatal com-plication during orthopedic surgery. Different causative factors have been suggested, but the exact pathomechanism of FE still remains unclear. We investigated the role of polymethylmethacrylate (PMMA) in FE during vertebroplasty in sheep.

METHODS

In 8 sheep, two vertebral bodies were augmented alternatively with PMMA or bone wax. Pulmonary and cardiovascular parameters were monitored during the procedure.

RESULTS

The peak response was similar for both groups and characterized by hypotension, a drop in cardiac output and pulmonary hypertension. However, the recovery in pulmonary arterial pressure and pulmonary vascular resistance was quicker in the wax group.

INTERPRETATION

The injection of PMMA may cause prolonged pulmonary hypertension during vertebro-plasty and also arthroplasty. Surgeons should be aware of this potential cardiovascular complication, especially in patients with impaired pulmonary and cardiovascular function.

Mixture of honey, beeswax and olive oil inhibits growth of Staphylococcus aureus and Candida albicans

BACKGROUND

Honey, beeswax and olive oil mixture (1:1:1, v/v) is useful in the treatment of diaper dermatitis, psoriasis and eczema. The study was designed to investigate effects of honey, olive oil, and beeswax and the mixture on growth of Staphylococcus aureus and Candida albicans isolated from human specimens.

METHODS

The following experiments were performed: 1) honey mixture was poured on holes made on plates seeded with S. aureus or C. albicans, 2) the microorganisms were cultured onto media made of honey mixture alone, nutrient agar-honey mixture and Sabouraud glucose agar-honey mixture. The concentration of honey mixture in nutrient agar or Sabouraud glucose agar was 12.5, 25, 33, 50 and 66% (v/v), and 3) honey, olive oil or beeswax was added onto nutrient agar or Sabouraud glucose agar at a ratio of 1:2 (v/v) and then were seeded with S. aureus or C. albicans.

RESULTS

Clear zone of inhibition was observed around holes filled with honey mixture; 3.5 mm on media seeded with C. albicans and 4 mm on media seeded with S. aureus. No growth of either microorganism was obtained on media made of honey mixture alone. The minimum concentration of honey mixture in nutrient agar-honey mixture media required to inhibit S. aureus was 50% and 66% concentration was required to inhibit C. albicans growth onto Sabouraud glucose agar-honey mixture media. No growth of S. aureus or C. albicans was obtained on media containing honey whereas mild to moderate growth was obtained on media containing olive oil or beeswax.

CONCLUSIONS

Honey and honey mixture apparently could inhibit growth of S. aureus or C. albicans.

Effect of the epicuticular waxes of fruits and vegetables on the photodegradation of rotenone

The effect of epicuticular waxes extracted from fruits (apple, nectarine, pear, and plum) and vegetables (tomato and eggplant) on the photodegradation of rotenone was studied. The waxes affected the decay rate and the degradation pathway of this botanical insecticide. Tomato, nectarine, and plum waxes decreased the photodegradation rate compared to controls, whereas apple and pear waxes increased it. Rotenone irradiated under sunlight without waxes gave seven photoproducts; in contrast, in the presence of waxes it changed its behavior, leading to different pathways according to the wax employed. The main photoproduct formed was 12abeta-rotenolone.

Monoterpenes and Epicuticular Waxes Help Female Autumn Gum Moth Differentiate Between Waxy and Glossy Eucalyptus and Leaves of Different Ages

The autumn gum moth, Mnesampela privata, is a native Australian species whose preferred host, Eucalyptus globulus (Myrtaceae), is an aromatic evergreen tree that has long-lived waxy leaves during the juvenile phase of growth. We compared the behavioral and antennal responses of female moths to whole leaves (new and old) and samples of foliar chemicals (from new and old leaves) from a typical E. globulus subsp. pseudoglobulus with responses to a glossy, half-sibling E. g. subsp. pseudoglobulus putative hybrid (the result of natural cross-pollination). We also studied larval survival and development on leaves from the same trees. In laboratory binary-choice assays, female M. privata laid more eggs on waxy leaves than on glossy leaves thereby confirming the nonpreference for the glossy tree that was observed in the field. Analyses of the monoterpenes and waxes of both trees revealed that they had comparable suites of monoterpenes and total oil contents but different suites of epicuticular waxes. Headspace extracts differed in the intensity of component monoterpenes. Gas chromatographic analyses with electroantennographic detection showed different patterns of monoterpene detection. Leaves of the glossy tree had a less diverse array of epicuticular waxes than those of the waxy tree. Electroantennographic screening of responses to wax extracts from leaves (new and old) from either tree revealed positive dose-dependent responses of female antennae to waxes from new leaves only. Binary-choice assays also revealed a strong preference by ovipositing females for new, compared to old, leaves whether they were from the waxy or the glossy tree. However, new leaves from either tree could be manipulated (by physical abrasion of epicuticular waxes) so that females would lay almost no eggs on them. Larval survival did not differ between groups reared on leaves from both trees (new and old). Over 70% of all larvae survived to pupation. However, larvae reared on leaves from the glossy tree took longer to pupate than those reared on leaves from the waxy tree. Also, larvae reared on new leaves from either tree did not perform as well as those reared on old leaves. Monoterpene and wax cues are suggested as helping female M. privata locate preferred hosts in native forests.

Therapeutic Constituents and Actions of Rubus Species

Rubus species (family Rosaceae) have been cultivated for centuries for their fruits. These and other parts of the plants have been used traditionally for therapeutic purposes. This article highlights these and the potential they can offer. The constituents reported in the various species and those demonstrated to exhibit pharmacological properties have been reviewed. In the search for biologically active compounds, one of the most frequently documented species of the genus is the raspberry plant R. idaeus, the leaves of which have been used traditionally as a uterine relaxant and stimulant during confinement, for the treatment of diarrhoea and similar enteric disorders and as an astringent. Investigations of other Rubus species have been conducted in the last twenty-five years, and have shown possible application for a wide range of indications, including bacterial infections, anxiety, pain and inflammation.

Plant waxy bloom on peas affects infection of pea aphids by Pandora neoaphidis

This study examined the effects of the surface wax bloom of pea plants, Pisum sativum, on infection of pea aphids, Acyrthosiphon pisum, by the fungal pathogen Pandora neoaphidis. In prior field surveys, a higher proportion of P. neoaphidis-killed pea aphids (cadavers) had been observed on a pea line with reduced wax bloom, as compared with a sister line with normal surface wax bloom. Laboratory bioassays were conducted in order to examine the mechanisms. After plants of each line infested with aphids were exposed to similar densities of conidia, the rate of accumulation of cadavers on the reduced wax line was significantly greater than on the normal wax bloom line; at the end of the experiment (13d), the proportion of aphid cadavers on the reduced wax line was approximately four times that on the normal wax bloom line. When plants were exposed to conidia first and then infested with aphids, the rate of accumulation of cadavers was slightly but significantly greater on the reduced wax line, and infection at the end of the experiment (16d) did not differ between the lines. When aphids were exposed first and then released onto the plants, no differences in the proportion of aphid cadavers were observed between the pea lines. Greater infection of pea aphid on reduced wax peas appears to depend upon plants being exposed to inoculum while aphids are settled in typical feeding positions on the plant. Additional experiments demonstrated increased adhesion and germination by P. neoaphidis conidia to leaf surfaces of the reduced wax line as compared with normal wax line, and this could help explain the higher infection rate by P. neoaphidis on the reduced wax line. In bioassays using surface waxes extracted from the two lines, there was no effect of wax source on germination of P. neoaphidis conidia.

Independence of circadian entrainment state and responses to melatonin in male Siberian hamsters

Background

Seasonal fluctuations in physiology and behavior depend on the duration of nocturnal melatonin secretion programmed by the circadian system. A melatonin signal of a given duration, however, can elicit different responses depending on whether an animal was previously exposed to longer or shorter photoperiod signals (i.e., its photoperiodic history). This report examined in male Siberian hamsters which of two aspects of photoperiod history – prior melatonin exposure or entrainment state of the circadian system – is critical for generating contingent responses to a common photoperiodic signal.

Results

In Experiment #1, daily melatonin infusions of 5 or 10 h duration stimulated or inhibited gonadal growth, respectively, but had no effect on entrainment of the locomotor activity rhythm to long or short daylengths, thereby demonstrating that melatonin history and entrainment status could be experimentally dissociated. These manipulations were repeated in Experiment #2, and animals were subsequently exposed to a 12 week regimen of naturalistic melatonin signals shown in previous experiments to reveal photoperiodic history effects. Gonadal responses differed as a function of prior melatonin exposure but were unaffected by the circadian entrainment state. Experiment #3 demonstrated that a new photoperiodic history could be imparted during four weeks of exposure to long photoperiods. This effect, moreover, was blocked in animals treated concurrently with constant release melatonin capsules that obscured the endogenous melatonin signal: Following removal of the implants, the gonadal response depended not on the immediately antecedent circadian entrainment state, but on the more remote photoperiodic conditions prior to the melatonin implant.

Conclusions

The interpretation of photoperiodic signals as a function of prior conditions depends specifically on the history of melatonin exposure. The photoperiodic regulation of circadian entrainment state contributes minimally to the interpretation of melatonin signals.

Cuticular lipids and silverleaf whitefly stage affect conidial germination of Beauveria bassiana and Paecilomyces fumosoroseus

Beauveria bassiana and Paecilomyces fumosoroseus are generalist entomopathogenic fungi that infect the silverleaf whitefly (Bemisia argentifolii). We found second and third instar whiteflies to be the most susceptible larval stage to both fungi. Conidia of B. bassiana germinated most readily on the cuticle of second instars (54% germinated) and P. fumosoroseus germination was highest on third instar cuticle (45%). Fourth instars (the ultimate instar) had low susceptibility to these pathogens, and spore germination on the cuticle of fourth instars was very low for B. bassiana (7%) and intermediate for P. fumosoroseus (33%). Cuticular lipids were found to have toxic or inhibitory effects on conidia of B. bassiana and P. fumosoroseus when the spores were germinated on nutrient agar in the presence of the lipids. In the absence of added nutrients, P. fumosoroseus conidial germination increased in the presence of the lipids. To test if the inhibitory effects of the lipids were due solely to hydrophobicity (preventing water from coming into contact with the conidia) we tested the effects of synthetic long-chain wax esters. The synthetic wax esters inhibited germination of P. fumosoroseus to a degree that was similar to the effect of the cuticular lipid extracts, but the synthetic lipids did not have a significant effect on B. bassiana. Thus, the thick coating of long-chain wax esters produced by whitefly nymphs affect spore germination of fungal pathogens, but whether they play a significant role in defense against disease is not clear.

Pressurization of vertebral bodies during vertebroplasty causes cardiovascular complications: an experimental study in sheep

STUDY DESIGN

An experimental study of cardiovascular complications arising during vertebroplasty (VP) of multiple levels in sheep.

OBJECTIVES

To investigate the effect of pressurizing vertebral bodies during VP using different materials in the development of fat embolism (FE) and any associated cardiovascular changes.

SUMMARY OF BACKGROUND DATA

Polymethylmethacrylate (PMMA) is the material of choice for VP. However, PMMA has several disadvantages, such as toxicity, exothermic curing, uncertain long-term biomechanical effects, and biocompatibility. Alternative materials are being developed for VP; however, there is the concern that an increase in intraosseous pressure and displacement of bone marrow contents could lead to FE and hypotension during VP regardless of what type of materials is used.

METHODS

In 20 sheep, four vertebral bodies were augmented either with PMMA or bone wax. Heart rate; arterial, central venous, and pulmonary artery pressure; cardiac output; and blood gas values were recorded. Postmortem the lungs were subjected to histologic evaluation.

RESULTS

The consecutive augmentation of four vertebral bodies with PMMA induced a cumulative FE that gradually deteriorated baseline mean arterial blood pressure (MABP) and blood gas values. The augmentation with bone wax resulted in similar cardiovascular changes and amount of intravascular fat in the lungs.

CONCLUSION

There are potential cardiovascular complications during VP of multiple levels regardless of the augmentation material used. The deteriorating baseline MABP during VP is associated with the pressurization of the vertebral bodies rather than with the use of polymethylmethacrylate.

Respiratory metabolic responsiveness during the pupal stage of the red palm weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae) to certain plant extracts

The prepupae of Rhynchophorus ferrugineous were topically applied with one of three dose-levels (0.1, 0.005 or 0.001 microgram/insect) of Jojoba oil (Joj) or azadirachtin (Azt). The daily O2 consumption and CO2 respiratory output were determined and the respiratory quotient (RQ) was calculated. After Joj treatments, O2 consumption of early- and late pupae increased as the dose-level was decreased. The respiration curve did not assume an U-shaped pattern as common in the pupal stage of many insect species. Also, an inhibitory action of Azt on the pupal respiration has been clearly exhibited. A similar result of the respiration curve was observed by Azt. All dose levels of Joj, but only the higher two ones of Azt, suppressed the CO2 release. Both botanicals inhibited the RQ during the pupal stage. However, all RQ mean values of treated or control pupae were < 1.0 and > 0.7.

Inhibition of osteoporosis in rats fed with sugar cane wax

Rats fed on a restricted, semi-purified diet containing a 50%-reduced level of carbohydrate and oil, but normal levels of protein, minerals and vitamins, exhibited osteoporosis. However, rats fed on this restricted diet, but containing sugar cane wax, did not exhibit this bone disease. Sugar cane wax, containing a long-chain carbohydrate with an OH radical, prevented the development of osteoporosis via a non-estrogenic mechanism.

Survival of Escherichia coli O157:H7 and Salmonella Muenchen on apples as affected by application of commercial fruit waxes

Survival of Escherichia coli O157:H7, Salmonella Muenchen, and yeasts and molds on apples as affected by application of five commercial apple waxes was investigated. Red Delicious cv. apples at 21 degrees C were spot inoculated with E. coli O157:H7 and S. Muenchen and spray coated with waxes. Apples sprayed with water served as controls. Apples were dried at either 21 or 55 degrees C for 2 min before subjecting to microbiological analysis after storage for 0, 1, 3, 6, and 12 weeks at 2 or 21 degrees C. Drying temperature did not significantly influence populations of E. coli O157:H7 and S. Muenchen. Waxing reduced populations E. coli O157:H7 and S. Muenchen by up to 1.48 log10 cfu/apple. Compared to untreated apples, treatment of apples with water or waxes resulted in significant (P < or = 0.05) reductions in populations of E. coli O157:H7 and S. Muenchen during storage at 2 degrees C. Reductions on waxed apples stored at 21 degrees C were not as marked compared to reductions on waxed apples stored at 2 degrees C. With the exception of one wax, drying temperature did not significantly influence populations of yeasts and molds. Mold populations were less affected by wax applications than were yeasts, and were detected in higher numbers on apples treated with three of the five waxes compared to populations recovered from untreated control apples. None of the waxes evaluated can be relied upon to kill or remove E. coli O157:H7 and Salmonella on apples.

Vascular response of current and potential dental etchants

This study investigated the hemostatic properties of current and potential dentin conditioners by observing the contraction of blood vessels using the rat carotid artery model. Four different agents (3M Scotchbond etchant, NRC, RC-Prep, File-Eze) were used. Dose-dependent contractions/relaxations of the test materials were first compared with epinephrine, followed by administration of papaverine, which was used to reverse epinephrine-induced contractions. In all sequences, the contraction or relaxation forces produced by the test and control materials were recorded using a force displacement transducer. RC-Prep was the only agent to produce epinephrine-like contractions (vasoconstriction) in the rat carotid artery. No contraction could be achieved with 3M etchant. Dose-dependent relaxations were observed with 3M etchant, which eventually led to collapse of the vessel wall; afterward, no response could be achieved with administration of adrenalin. File-Eze and NRC also did not cause vasoconstriction. Both materials caused dose-dependent relaxations in the smooth muscle. However, subsequent administration of adrenalin and papaverine caused dose-dependent contractions and relaxations, respectively, showing that these etchant effects did not lead to collapse of the vessel wall, as did 3M etchant.

Pine resin and Biopin ointment: effects on nonspecific resistance of organisms

We studied the effects of pine resin and Biopin ointment used for the therapy of burns, wounds, purulent and inflammatory diseases on blood leukocyte count, phagocytic activity of macrophages and neutrophils, and redox potential of peripheral blood neutrophils. The wound-healing effect of the test preparations is determined by their ability to activate phagocytosis.

Identification of chemical components of corn kernel pericarp wax associated with resistance to Aspergillus flavus infection and aflatoxin production

Kernel pericarp wax of the corn breeding population GT-MAS:gk has been associated with resistance to Aspergillus flavus infection and aflatoxin production. GT-MAS:gk wax, previously compared to waxes of three susceptible genotypes, was presently compared to wax of a different, and more numerous, group of susceptible lines. Wax separation by TLC confirmed previous findings, demonstrating a unique GT-MAS:gk band and a unique "susceptible" band. Only GT-MAS:gk wax inhibited the growth of A. flavus; however, no association was established, as before, between kernel wax abundance and resistance. Gas chromatography-mass spectroscopy (GC-MS) analysis of kernel whole wax showed a higher percentage of phenol-like compounds in wax from GT-MAS:gk than in waxes from the susceptible lines. The GT-MAS:gk unique band contained phenol-like compounds and ethyl-hexadecanoate; butyl-hexadecanoate was preeminent in most of the "susceptible bands". Alkylresorcinol (phenolic compounds) content was dramatically higher in GT-MAS:gk wax than in the wax of susceptible lines. An alkylresorcinol, 5-methylresorcinol, also inhibited in vitro growth of A. flavus. These and other phenolic compounds may contribute to kernel wax inhibition of A. flavus infection/aflatoxin production. Further investigation is needed to confirm a role for them in GT-MAS:gk resistance.

Protecting against water loss: analysis of the barrier properties of plant cuticles

The cuticle is the major barrier against uncontrolled water loss from leaves, fruits and other primary parts of higher plants. More than 100 mean values for water permeabilities determined with isolated leaf and fruit cuticles from 61 plant species are compiled and discussed in relation to plant organ, natural habitat and morphology. The maximum barrier properties of plant cuticles exceed that of synthetic polymeric films of equal thickness. Cuticular water permeability is not correlated to the thickness of the cuticle or to wax coverage. Relationships between cuticular permeability, wax composition and physical properties of the cuticle are evaluated. Cuticular permeability to water increases on the average by a factor of 2 when leaf surface temperature is raised from 15 degrees C to 35 degrees C. Organic compounds of anthropogenic and biogenic origin may enhance cuticular permeability. The pathway taken by water across the cuticular transport barrier is reviewed. The conclusion from this discussion is that the bulk of water diffuses as single molecules across a lipophilic barrier while a minor fraction travels along polar pores. Open questions concerning the mechanistic understanding of the plant cuticular transport barrier and the role the plant cuticle plays in ensuring the survival and reproductive success of an individual plant are indicated.

Effects of chelating agents and sodium hypochlorite on mineral content of root dentin

Effects of combined and single use of EDTA, RC-Prep, and NaOCl on mineral content of root dentin were evaluated in vitro using energy dispersion spectrometric microanalysis. Thirty-six standardized midroot dentin specimens obtained from human anterior teeth were used. Specimens were polished and divided into six experimental groups. The first two groups were treated with EDTA or RC-Prep followed by NaOCl irrigation. Groups 3 to 5 were treated with EDTA, RC-Prep, and NaOCl, respectively. The last group was irrigated with saline solution as a control. Levels of calcium, phosphorus, and magnesium were measured in the root dentin after treatments. The results showed that (i) EDTA combined with NaOCl irrigation as final flush and NaOCl alone changed the calcium/phosphorus ratio of root dentin significantly (p < 0.05); and (ii) there was a significant increase in the magnesium level after the use of chelating agent combined with NaOCl (p < 0.05). It was concluded that using NaOCl irrigation as final flush altered the effectiveness of chelating agents on root dentin.

Photolysis of pesticides: influence of epicuticular waxes from Persica laevis DC on the photodegradation in the solid phase of aminocarb, methiocarb and fenthion

Pesticides with N,N-dimethyl and thiomethyl moieties (aminocarb, methiocarb and fenthion) were irradiated under artificial light (lambda > 290 nm) in an amorphous wax phase from Persica laevis DC. The effect of the presence of the wax on the photolysis rate differed in the three pesticides, increasing it in aminocarb, having little effect in methiocarb and slowing it down in fenthion. The presence of the wax affected the qualitative photodegradation behaviour of all the pesticides. The data obtained were compared with those for pirimicarb, which had been studied earlier.

A mitogen-activated protein kinase kinase required for induction of cytokinesis and appressorium formation by host signals in the conidia of Colletotrichum gloeosporioides

Differentiation of fungal conidia of phytopathogens into the infection structure, appressorium, requires contact with a hard surface and host signals. The molecular signaling involved in the induction of this differentiation is poorly understood. We report the cloning of a mitogen-activated protein kinase kinase (MEK), CgMEK, from Colletotrichum gloeosporioides and its role in the induction of these developmental processes involved in pathogenesis. Disruption of CgMEK1 resulted in the loss of its ability to form appressoria in response to the host's signals and a loss of virulence. Results of confocal microscopic examination of germinating conidia of the gene-disrupted mutants were similar to those for wild-type conidia treated with an MEK inhibitor, suggesting that CgMEK1 is involved in two developmental processes in the differentiation into appressorium: (1) polarized cell division, with the preferential increase in F-actin in one of the daughter nuclei after nuclear division and the formation of septum; and (2) differentiation of the germ tube into an appressorium. CgMEK1 is required for the differentiation.

Effect of diluents on tablet integrity and controlled drug release

The objective of this study was to evaluate the effect of diluents and wax level on tablet integrity during heat treatment and dissolution for sustained-release formulations and the resultant effect on drug release. Dibasic calcium phosphate dihydrate (DCPD), microcrystalline cellulose (MCC), and lactose were evaluated for their effect on tablet integrity during drug dissolution and heat treatment in wax matrix formulations. A newly developed direct compression diluent, dibasic calcium phosphate anhydrous (DCPA), was also evaluated. Compritol 888 ATO was used as the wax matrix material, with phenylpropanolamine hydrochloride (PPA) as a model drug. Tablets were made by direct compression and then subjected to heat treatment at 80 degrees C for 30 min. The results showed that MCC, lactose, and DCPA could maintain tablets intact during heat treatment above the melting point of wax (70 degrees C-75 degrees C). However, DCPD tablets showed wax egress during the treatment. MCC tablets swelled and cracked during drug dissolution and resulted in quick release. DCPD and lactose tablets remained intact during dissolution and gave slower release than MCC tablets. DCPA tablets without heat treatment disintegrated very quickly and showed immediate release. In contrast, heat-treated DCPA tablets remained intact through the 24-hr dissolution test and only released about 80% PPA at 6 hr. In the investigation of wax level, DCPD was used as the diluent. The drug release rate decreased as the wax content increased from 15% to 81.25%. The dissolution data were best described by the Higuchi square-root-of-time model. Diluents showed various effects during heat treatment and drug dissolution. The integrity of the tablets was related to the drug release rate. Heat treatment retarded drug release if there was no wax egress.

In vitro antimicrobial effect of RC-Prep within dentinal tubules

The antimicrobial effect of RC-Prep and its components--10% urea peroxide, 15% EDTA, and glycol--were evaluated individually, in vitro, within dentinal tubules. Standardized bovine incisor root specimens that had been infected with either Staphylococcus aureus or Streptococcus peltzer were incubated with each agent for 10 and 45 min. After exposure to the agent, dentin samples were collected from within the lumina using ISO 23 to 31 burs. Dentin powder samples were incubated with bacterial broth, and the amount of bacteria present was assessed by spectrophotometry. All agents tested were more effective in killing bacteria after incubation for 45 min than after 10 min.

In vitro disinfection of dentinal tubules by various endodontics irrigants

Effectiveness of endodontic irrigants within dentinal tubules of human teeth was evaluated. Mid-sections of single-rooted teeth were prepared into dentin wedges. The pulpal sides of the sections were exposed to Micrococcus luteus or Bacillus megaterium that grew into the tubules. Irrigants used in the study included: 0.525% NaOCl, 0.12% chlorhexidine, RC Prep, 0.5% betadine iodine, and sterile H2O (as a control). Pulpal surfaces were exposed to an irrigant and then rinsed in sterile water. The samples were then cracked, exposing a fresh surface. Culture of the exposed dentin surfaces showed that selected irrigants reached to the far ends of the dentinal tubules in a concentration sufficient to kill 100% of the M. luteus. However B. megaterium was neither killed nor apparently inhibited by any irrigant. We conclude that endodontic irrigants permeate throughout dentinal tubules, but their effectiveness is dependent on the type of bacteria found within the tubules.

TMC-171A,B,C and TMC-154, novel polyketide antibiotics produced by Gliocladium sp. TC 1304 and TC 1282

Four new antibiotics, TMC-171A (2), B (3), C (4) and TMC-154 (5) have been isolated from the fermentation of fungal strains Gliocladium sp. TC 1304 and TC 1282, respectively. Spectroscopic and degradation studies have shown that TMC-171s and TMC-154 were new members of the TMC-151 class of antibiotics, unique polyketides modified with a D-mannose and a D-mannitol or a D-arabitol. These compounds showed moderate cytotoxicity to various tumor cell lines.

In vitro antibacterial effect of RC-Prep components on Streptococcus sobrinus

The aim of this study was to examine the bacteriostatic and bactericidal effects of the components of RC-Prep: EDTA, urea peroxide and glycol. The minimal inhibitory concentration and the minimal bactericidic concentration of EDTA, urea peroxide and glycol were tested on the viability of Streptococcus sobrinus (S. sobrinus). The combined antibacterial effect of these components was also examined on S. sobrinus. The minimal inhibitory concentration of EDTA was found to be 0.125%, of urea peroxide 0.25%, and of glycol 30%. The minimal bactericidic concentration of EDTA was 0.25%, of urea peroxide 0.5% and of glycol 50%. An antibacterial synergistic effect was found between specific combinations of urea peroxide, EDTA and glycol. No antagonistic effects were found in the various combinations between the components. The antimicrobial effect of the components of RC-Prep was enhanced in specific combinations of the ingredients. This effect might contribute to the intracanal cleansing properties of this medication.

Effect of chelating agents on the molecular composition and extent of decalcification at cervical, middle and apical root dentin locations

The aim of this study was to investigate the interaction of two chelating agents used in endodontic treatment with dentin from different root locations. Standardized cervical, middle and apical root dentin specimens were prepared and subjected to treatment with 15% neutral EDTA and RCPrep. Following rinsing with water, dentin surfaces were studied by reflected light optical microscopy and micro-MIR FTIR spectroscopy, while the wash-off extracts were analyzed by atomic absorption spectrometry (AAS) to determine the content of calcium and phosphorus. Neutral EDTA removed the smear layer and opened tubules while RCPrep did not. FTIR measurements showed higher decalcification of dentin surfaces after neutral EDTA treatment although its effect was reduced at apical regions. AAS measurements of calcium and phosphorus confirmed the higher dentin dissolution potential of EDTA at cervical and middle root dentin locations. The results of the present study implied different reaction modes for the two chelating agents tested which might affect the efficiency of the chemo-mechanical preparation when these agents are used.

Early expression of the calmodulin gene, which precedes appressorium formation in Magnaporthe grisea, is inhibited by self-inhibitors and requires surface attachment

Fungal conidia contain chemicals that inhibit germination and appressorium formation until they are well dispersed in a favorable environment. Recently, such self-inhibitors were found to be present on the conidia of Magnaporthe grisea, and plant surface waxes were found to relieve this self-inhibition. To determine whether the self-inhibitors suppress the expression of early genes involved in the germination and differentiation of conidia, the calmodulin gene was chosen as a representative early gene, because it was found to be expressed early in Colletotrichum gloeosporioides and Colletotrichum trifolii differentiation. After calmodulin cDNA and genomic DNA from M. grisea were cloned, the promoter of the calmodulin gene was fused to a reporter gene, that for green fluorescent protein (GFP), and transformed into the M. grisea genome. Confocal microscopic examination and quantitation of expression of GFP green fluorescence showed (i) that the expression of the calmodulin gene decreased significantly when self-inhibition of M. grisea appressorium formation occurred because of high conidial density or addition of exogenous self-inhibitors and (ii) that the expression level of this gene was restored when self-inhibition was relieved by the addition of plant surface waxes. The increase in fluorescence correlated with the percentage of conidia that formed appressoria. The induction of calmodulin was also confirmed by RNA blotting. Concanavalin A inhibited surface attachment of conidia, GFP expression, and appressorium formation without affecting germination. The high correlation between GFP expression and appressorium formation strongly suggests that calmodulin gene expression and appressorium formation require surface attachment.

A scanning electron microscopic study of the cleansing effectiveness of three irrigating modalities on the tubular structure of dentin

This is a scanning electron microscope study of the cleaning effectiveness of three irrigating modalities on root dentin. When hydrogen peroxide was followed by sodium hypochlorite, it effectively cleaned the dentinal tubules of the root. When RC-Prep was reacted with sodium hypochlorite, it proved to be a more efficient irrigating method than the hydrogen peroxide and sodium hypochlorite solution. When a new improved RC-Prep with 15% carbanide peroxide was reacted with sodium hypochlorite, it proved to be a superior cleansing method for root dentin.