High-yield expression,purification, characterization,and structure determination of tag-free <Emphasis Type="Italic">Candida utilis</Emphasis> uricase

We report the successful high-yield expression of Candida utilis uricase in Escherichia coli and the establishment of an efficient three-step protein purification protocol. The purity of the recombinant protein, which was confirmed to be C. utilis uricase by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analysis, was >98% and the specific activity was 38.4 IU/mg. Crystals of C. utilis uricase were grown at 18°C using 25% polyethylene glycol 3350 as precipitant. Diffraction by the crystals extends to 1.93 Å resolution, and the crystals belong to the space group P2₁2₁2₁ with unit cell parameters a?=?69.16 Å, b?=?139.31 Å, c?=?256.33 Å, and α?=?β?=?γ?=?90°. The crystal structure of C. utilis uricase shares a high similarity with other reported structures of the homologous uricases from other species in protein database, demonstrating that the three-dimensional structure of the protein defines critically to the catalytic activities.     

The nitrite reductase activity of horse heart carboxymethylated-cytochrome <Emphasis Type="Italic">c</Emphasis> is modulated by cardiolipin

Horse heart carboxymethylated cytc (CM-cytc) displays myoglobin-like properties. Here, the effect of cardiolipin (CL) liposomes on the nitrite reductase activity of ferrous CM-cytc [CM-cytc-Fe(II)], in the presence of sodium dithionite, is reported between pH 5.5 and 7.6, at 20.0 °C. Cytc-Fe(II) displays a very low value of the apparent second-order rate constant for the NO₂ ^?-mediated conversion of cytc-Fe(II) to cytc-Fe(II)-NO [k _on = (7.3 ± 0.7) × 10^?2 M^?1 s^?1; at pH 7.4], whereas the value of k _on for NO₂ ^? reduction by CM-cytc-Fe(II) is 1.1 ± 0.2 M^?1 s^?1 (at pH 7.4). CL facilitates the NO₂ ^?-mediated nitrosylation of CM-cytc-Fe(II) in a dose-dependent manner, the value of k _on for the NO₂ ^?-mediated conversion of CL–CM-cytc-Fe(II) to CL–CM-cytc-Fe(II)-NO (5.6 ± 0.6 M^?1 s^?1; at pH 7.4) being slightly higher than that for the NO₂ ^?-mediated conversion of CL–cytc-Fe(II) to CL–cytc-Fe(II)-NO (2.6 ± 0.3 M^?1 s^?1; at pH 7.4). The apparent affinity of CL for CM-cytc-Fe(II) is essentially pH independent, the average value of B being (1.3 ± 0.3) × 10^?6 M. In the absence and presence of CL liposomes, the nitrite reductase activity of CM-cytc-Fe(II) increases linearly on lowering pH and the values of the slope of the linear fittings of Log k _on versus pH are ?1.05 ± 0.07 and ?1.03 ± 0.03, respectively, reflecting the involvement of one proton for the formation of the transient ferric form, NO, and OH^?. These results indicate that Met80 carboxymethylation and CL binding cooperate in the stabilization of the highly reactive heme-Fe atom of CL–CM-cytc.     

Striking Effects of Storage Buffers on Apparent Half-Lives of the Activity of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> Arylsulfatase

To obtain the label enzyme for enzyme-linked-immunoabsorbent-assay of two components each time in one well with conventional microplate readers, molecular engineering of Pseudomonas aeruginosa arylsulfatase (PAAS) is needed. To compare thermostability of PAAS/mutants of limited purity, effects of buffers on the half-activity time (t _0.5) at 37 °C were tested. At pH 7.4, PAAS showed non-exponential decreases of activity, with the apparent t _0.5 of ~6.0 days in 50 mM HEPES, but ~42 days in 10 mM sodium borate with >85 % activity after 15 days; protein concentrations in both buffers decreased at slower rates after there were significant decreases of activities. Additionally, the apparent t _0.5 of PAAS was ~14 days in 50 mM Tris–HCl, and ~21 days in 10 mM sodium phosphate. By sodium dodecyl-polyacrylamide gel electrophoresis, the purified PAAS gave single polypeptide; after storage for 14 days at 37 °C, there were many soluble and insoluble fragmented polypeptides in the HEPES buffer, but just one principal insoluble while negligible soluble fragmented polypeptides in the borate buffer. Of tested mutants in the neutral borate buffer, rates for activity decreases and polypeptide degradation were slower than in the HEPES buffer. Hence, dilute neutral borate buffers were favorable for examining thermostability of PAAS/mutants.     

Comparative Pharmaceutical Evaluation of Candesartan and Candesartan Cilexetil: Physicochemical Properties, <Emphasis Type="Italic">In Vitro</Emphasis> Dissolution and <Emphasis Type="Italic">Ex Vivo In Vivo</Emphasis> Studies

The aim of the present work is to answer the question is it possible to replace the ester prodrug candesartan cilexetil (CC) by its active metabolite candesartan (C) to bypass the in vivo variable effect of esterase enzymes. A comparative physicochemical evaluation was conducted through solubility, dissolution, and stability studies; additionally, ex vivo permeation and in vivo studies were assessed. C demonstrated higher solubility over CC at alkaline pH. Moreover, dissolution testing using the pharmacopeial method showed better release profile of C even in the absence of surfactant in the testing medium. Both drugs demonstrated a slight degradation in acidic pH after short-term stability. Instead, shifting to alkaline pH of 6.5 and 7.4 showed superiority of C solution stability compared to CC solution. The ex vivo permeation results demonstrated that the parent compound C has a significant (P < 0.05) enhanced permeation compared to its prodrug from CC, that agreed with in vivo results in which C suspension reached significantly (P < 0.05) higher C _max of 1.39 ± 0.59 μg/mL at T _max of 0.66 ± 0.11 h, while CC suspension reached C _max of 0.47 ± 0.22 μg/mL at T _max of 2.00 ± 0.27 h, a lag period of 40 min is needed prior to detection of any absorbed CC in plasma. Those findings are not in agreement with the previously reported rationale on the prodrug formation owing to the poor permeability of the parent compound, suggesting the possibility of marketing the parent drug candesartan for clinical use similarly to azilsartan and its prodrug.     

Cold storage of <Emphasis Type="Italic">Trichogramma nerudai</Emphasis> using an acclimation period

The availability of suitable storage methods for parasitoids is a valuable tool in biological control programs. Studies were conducted to investigate the effects of cold storage with acclimation period on the quality of Trichogramma nerudai Pintureau and Gerding. Prepupae were stored 50, 75 and 100 days at 5 °C with a previous acclimation period of 10 or 20 days at 12 °C. It was possible to arrest the development of T. nerudai. All the treatments with acclimation period of ten days had emergence values under 10% that were not useful to establish a cold storage protocol. Twenty days of acclimation had a positive impact on cold storage tolerance at 50 and 75 days. The adult emergence, the emergence time, the sex ratio, the parasitism and the progeny quality have not been affected by the storage of T. nerudai using an acclimation period of 20 days and until 50 days under cold temperature.     

Development of <Emphasis Type="Italic">Cleruchoides noackae</Emphasis>, an egg-parasitoid of <Emphasis Type="Italic">Thaumastocoris peregrinus</Emphasis>, in eggs laid on different substrates,with different ages and post-cold storage

Cleruchoides noackae Lin and Huber (Hymenoptera: Mymaridae) is an egg parasitoid of Thaumastocoris peregrinus Carpintero and Dellapé (Hemiptera: Thaumastocoridae). The parasitism and development of C. noackae was studied in T. peregrinus eggs of different ages, laid on eucalyptus leaves or paper towel and stored at 5 °C. The emergence, sex ratio and development of C. noackae and hatched nymphs of T. peregrinus were evaluated. This parasitoid had an emergence rate higher than 60% from zero to one, one to two, and two to three-day old eggs and lower than 10% for those 3–4 and 4–5 days old. The female proportion was 78% and the egg-adult period for C. noackae was 19.5 days. The use of T. peregrinus eggs up to three days old, laid on paper towel and stored at 5 °C for 14 days did not affect the biological parameters of C. nockae and should be used for mass rearing of this parasitoid.     

Population Growth Parameters of Rose Aphid, <Emphasis Type="Italic">Macrosiphum rosae</Emphasis> (Hemiptera: Aphididae) on Different Rose Cultivars

The rose aphid, Macrosiphum rosae (L.), is one of the most important pests on rose plants (Rosa spp.) with a worldwide distribution. As resistance indices, the development, survivorship, and reproduction of this aphid were evaluated on 10 rose cultivars, including Bella Vita, Cool Water, Dolce Vita, Maroussia, Orange Juice, Pinkpromise, Roulette, Tea, Valentine, and Persian Yellow in laboratory at 25?±?1°C, 65?±?5% relative humidity, and photoperiod of 16:8 (L/D)?h. Rose aphid successfully survived on all 10 rose cultivars, although mortality rate was higher on Tea and Bella Vita. The number of offspring per female differed significantly among the tested rose cultivars, and ranged from 9.2 on Tea to 38.7 nymphs on Orange Juice. Population growth parameters were significantly affected by rose cultivars. The longest mean generation time (T) was observed on Bella Vita (14.8 days) and Tea (14.7 days) and the shortest on Orange Juice (10.0 days). The net reproductive rate (R ₀ ) ranged from 6.9 on Tea to 33.2 nymphs on Orange Juice cultivar. Correspondingly, the highest value of intrinsic rate of increase (r _m ) was observed on Orange Juice (0.348 day^?1) and lower values on Tea (0.131 day^?1) followed by Bella Vita (0.154 day^?1). Cluster analysis of all the measured parameters of rose aphid on different rose cultivars revealed that Tea and Bella Vita were relatively resistant to M. rosae. These findings could be useful in developing an integrated pest management (IPM) program for this aphid in urbanized areas and commercial rose potting.     

Effects of temperature on the development and circannual control of pupation in the carpenter moth, <Emphasis Type="Italic">Cossus insularis</Emphasis> (Lepidoptera: Cossidae), reared on an artificial diet

The effects of temperature on larval development and the timing of pupation in the carpenter moth, Cossus insularis (Staudinger) (Lepidoptera: Cossidae) were examined by artificial rearing under different temperatures and the same photoperiod (15L:9D). Although C. insularis pupated and emerged at 20, 25, and 30 °C, the pupation rate was lower at 20 °C than at 25 and 30 °C. These results suggest that the optimum temperature range for preadult development is 25–30 °C. The duration of larval development was about 260 days for the first pupation group at 25 and 30 °C, and at least 600 days at 20 °C. Therefore, the C. insularis generation time was 2 years or more, as the total effective temperature for development from hatching to the pupal stage was unlikely to be reached within 1 year in Tokushima Prefecture. The second group pupated at 25 °C, about 200 days after the first group. This periodicity of pupation was likely due to the free-running period of the circannual rhythm. Furthermore, although only the first group pupated at 30 °C, the peak was almost synchronous with the first group at 25 °C. These results indicate that the timing of the first pupation group in C. insularis is temperature compensated. Therefore we propose that the presence of an endogenous rhythm during the development of C. insularis is evidence for a circannual rhythm related to the timing of pupation.     

Effects of Copper and Zinc Supplementation on Weight Gain and Hematological Parameters in Pre-weaning Calves

Cow-calf operations may be affected by trace mineral deficiencies, particularly copper (Cu) and zinc (Zn) deficiency, which may decrease the calf daily weight gain and alter hematological parameters. We evaluated the effect of Cu and Zn supplementation on pre-weaning calves (n?=?40; 92?±?6 kg initial body weight) from the Salado River basin, Buenos Aires, Argentina. Calves were divided into four groups (n?=?10 each) and subcutaneously administered 0.3 mg/kg Cu (Cu group), 1 mg/kg Zn (Zn group), Cu and Zn together (Cu + Zn group), and sterile saline solution (control group) every 40 days for 120 days. Plasma Cu and Zn concentrations, hematological parameters, and weight were recorded every 40 days. A completely randomized 2?×?2 factorial treatment design was used and data were analyzed with a mixed model for repeated measures over time. Cu and Zn were detected in plasma after the second sampling. Cu × Zn interaction was significant (p?=?0.09), being Cu concentration higher in the Cu + Zn than in the Cu group. Differences in weight gain (Zn × time interaction; p?<?0.01) were observed in the Zn but not in the Cu group (p?>?0.1). On the other hand, none of the treatments altered any of the hematological parameters assessed (p?>?0.1). Our results show the risk of lower weight gain due to Zn deficiency in pre-weaning calves raised in the Salado River basin.     

Thermostable phycocyanin from the red microalga <Emphasis Type="Italic">Cyanidioschyzon merolae</Emphasis>, a new natural blue food colorant

The demand for natural food colorants is growing as consumers question the use of artificial colorants more and more. The phycobiliprotein C-phycocyanin of Arthospira platensis is used as a natural blue colorant in certain food products. The thermoacidophilic red microalga Cyanidioschyzon merolae might provide an alternative source of phycocyanin. Cyanidioschyzon merolae belongs to the order Cyanidiophyceae of the phylum Rhodophyta. Its natural habitat are sulfuric hot springs and geysers found near volcanic areas in, e.g., Yellowstone National Park in the USA and in Java, Indonesia. It grows optimally at a pH between 0.5 and 3.0 and at temperatures up to 56 °C. The low pH at which C. merolae grows minimizes the risk of microbial contamination and could limit production loss. As C. merolae lacks a cell wall, phycocyanin with a high purity number of 9.9 could be extracted by an osmotic shock using a simple ultrapure water extraction followed by centrifugation. The denaturation midpoint at pH 5 was 83 °C, being considerably higher than the A. platensis phycocyanin (65 °C). The C. merolae phycocyanin was relatively stable at pH 4 and 5 up to 80 °C. The high thermostability at slightly acidic pH makes the C. merolae phycocyanin an interesting alternative to A. platensis phycocyanin as a natural blue food colorant.     

Kinsenoside and polysaccharide production by rhizome culture of <Emphasis Type="Italic">Anoectochilus roxburghii</Emphasis> in continuous immersion bioreactor systems

Anoectochilus roxburghii (Wall) Lindl. (Orchidaceae) is a precious raw material for medicine. However, the wild resource of A. roxburghii has been endangered, and artificial cultivation results in low yields. To provide rhizomes of A. roxburghii as alternative plant materials, the present study used continuous immersion bioreactor systems to investigate several factors affecting rhizome biomass and bioactive compound accumulation. The bioreactor with a net at the bottom of the sphere in the bioreactor was suitable for production of rhizomes. The rhizome biomass and kinsenoside and polysaccharide accumulation peaked at 30 days of the bioreactor culture. Thus, 30 days was the appropriate culture period. Maximum rhizome biomass and kinsenoside and polysaccharide accumulation were determined when a bioreactor was inoculated with 12.5 g L^??1 (fresh weight) of rhizomes, aerated at 500 mL min^??1, and maintained under 45 µmol m^??2 s^??1 light intensity. This process resulted in the production of 2980.5 mg L^??1 of kinsenoside and 5672.9 mg L^?1 of polysaccharides.     

Expression of ethylene biosynthetic and signaling genes in relation to ripening of banana fruit after cold storage

Banana fruit are highly sensitive to chilling injury (CI), while the effect of different degrees of CI on the subsequent fruit ripening is largely unknown. In the present work, ripening characteristic of banana fruit after storage at 7 °C for 3 days or for 8 days, and expression levels of eight genes associated with ethylene biosynthetic and signaling, including MaACS1, MaACO1, MaERS1, MaERS3, and MaEIL1–4, were investigated. The results showed that banana fruit stored at 7 °C for 8 days exhibited more severe chilling symptoms than those at 7 °C for 3 days. Compared with banana fruit stored at 7 °C for 8 days, which showed abnormal ripening, more decrease in fruit firmness, while higher increase in ethylene production and hue angle were observed in banana fruit stored at 7 °C for 3 days, which could ripening normally. Moreover, gene expression profiles during ripening revealed that ethylene biosynthetic and signaling genes were differentially expressed in peel and pulp of banana fruit after storage at 7 °C for 3 days and 7 °C for 8 days. In the peel of fruit storage at 7 °C for 3 days, expression levels of MaACS1, MaACO1, MaEIL1, and MaEIL2 increased remarkably while MaERS3, MaEIL1, and MaEIL4 were enhanced in the fruit after storage at 7 °C for 8 days. In the pulp, with the exception of MaACO1 and MaERS3, expression levels of other genes did not exhibit a significant difference, between the banana fruit storage at 7 °C for 3 days and 7 °C for 8 days. Taken together, our results suggest that differential expression of ethylene biosynthetic and signaling genes such as MaERS3, MaACO1, and MaEIL2, may be related to ripening behavior of banana fruit with different degrees of CI after cold storage.     

A review of the history of research and control of <Emphasis Type="Italic">Rhipicephalus</Emphasis> (<Emphasis Type="Italic">Boophilus</Emphasis>) <Emphasis Type="Italic">microplus</Emphasis>, babesiosis and anaplasmosis in Uruguay

The effect of five constant temperatures (16, 20, 24, 28 and 32 °C) on the development, survival and reproduction of Tetranychus cinnabarinus (Boisduval) [=?Tetranychus urticae Koch (red form)] fed on cassava leaves was examined in the laboratory at 85% relative humidity. Development time of various immature stages decreased with increasing temperature, with total egg-to-adult development time varying from 27.7 to 6.7 days. The lower thermal threshold for development was 10.8 °C and the thermal constant from egg to adult was 142.4 degree-days. Pre- and post-oviposition period and female longevity all decreased as temperature increased. The longest oviposition period was observed at 20 °C with 20.4 days. Under different temperatures, mated females laid, on average, 1.0, 2.9, 4.7, 4.7 and 4.9 eggs per day, respectively. The maximum fecundity (81.5 eggs per female) was at 28 °C and the intrinsic rate of increase (r _m ) was highest (0.25) at 32 °C. The results of this study indicate that T. cinnabarinus population could increase rapidly when cassava leaves serve as a food source. At the appropriate temperature T. cinnabarinus could seriously threaten growth of cassava.     

Effects of Probiotics on Survival,Growth and Digestive Enzymes Activities in Freshwater Prawn <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis> (De Man 1879)

A study was conducted to examine the effects of three probiotics, Lactobacillus sporogenes, Bacillus subtilis and Saccharomyces cerevisiae on the survival, growth and digestive enzymes activities of the freshwater prawn Macrobrachium rosenbergii post larvae (PL). The probiotics, L. sporogenes (4 %), B. subtilis (3 %) and S. cerevisiae (4 %) were taken and mixed with basal diet. Diet without probiotics served as control. These probiotics diets were fed to M. rosenbergii PL for a period of 60 days. After the feeding trail, the growth parameters such as survival, weight gain, specific growth rate and protein efficiency rate were found to be significantly (P < 0.05) higher in 4 % S. cerevisiae incorporated diet fed PL when compared with control. In the case of feed conversion rate just the reverse was seen (P < 0.05) at this concentration. This indicates its superior quality among different concentrations of probiotics tested. Activities of digestive enzymes, such as protease, amylase and lipase were significantly (P < 0.05) higher at this concentration (4 % S. cerevisiae). Some of essential and non-essential amino acids also significantly elevated in probiotics supplemented diet fed prawns. This study indicated that probiotics, S. cerevisiae incorporated diets were beneficial for M. rosenbergii in terms of increasing growth, enzyme and amino acid production.     

Heterologous expression and characterisation of a laccase from <Emphasis Type="Italic">Colletotrichum lagenarium</Emphasis> and decolourisation of different synthetic dyes

Laccases have received considerable attention in recent decades because of their ability to oxidise a large spectrum of phenolic and non-phenolic organic substrates and highly recalcitrant environmental pollutants. In this research, a laccase gene from Colletotrichum lagenarium was chemically synthesised using yeast bias codons and expressed in Pichia pastoris. The molecular mass of the recombinant laccase was estimated to be 64.6 kDa by SDS–PAGE, and the enzyme exhibited maximum activity at pH 3.6–4.0 but more stability in buffer with higher pH (>pH 3.6). The optimal reaction temperature of the enzyme was 40 °C, beyond which stability significantly decreased. By using 2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulphonate (ABTS) as a substrate, K _m and V _max values of 0.34 mM and 7.11 mM min^?1 mg^?1, respectively, were obtained. Using ABTS as a mediator, the laccase could oxidise hydroquinone to p-benzoquinone and decolourise the synthetic dyes malachite green, crystal violet and orange G. These results indicated that the laccase could be used to treat industrial effluents containing artificial dyes.     

Periphyton nutrient content,biomass and algal community on artificial substrate: response to experimental nutrient enrichment and the effect of its interruption in a tropical reservoir

Periphyton plays an important functional role in the retention of nutrients in aquatic ecosystems, especially phosphorus. We evaluated the effects of enrichment with N and P and the effect after 20 days of no additional N and P on periphyton on artificial substratum in open-bottom mesocosms. The aim was to jointly evaluate periphyton, phytoplankton and zooplankton in the presence of macrophytes. Experimental conditions simulated natural conditions and nutrient addition was based on the maximum concentration recorded in mesotrophic reservoir. Our hypothesis is that the periphyton is sensitive to the effects of N and P enrichment and its interruption, despite the positive response of phytoplankton and zooplankton. Two treatments were designed using open-bottom mesocosms (n = 3): control (no nutrient addition); NP+ (combined phosphorus and nitrogen addition). Sampling for the measurement of biotic and abiotic variables was performed, with 10 days of continuous enrichment, on the 3rd, 6th and 11th, and 20 days after enrichment had ended (31st day). Periphyton chlorophyll a, dry mass and algal density increased significantly with the addition of N and P and decreased 20 days after the interruption of the enrichment. The highest periphyton P content was found in the NP+ treatment. The enrichment had a positive effect on Chrysophyceae (Chromulina spp.) and rotifer (Polyarthra spp.) density and the interruption of enrichment favored Bacillariophyceae (Gomphonema sp.) and rotifers (Gastropus stylifer). Phytoplankton responded positively to enrichment. Along with the high macrophyte coverage over the experimental period, we evidenced the positive effect enrichment had on phytoplankton biomass and zooplankton abundance. Therefore, periphyton on artificial substrate was sensitive to effects of N and P enrichment and its interruption, responding promptly to changes in nutrient availability in a scenario of high competition and grazing.     

Impact of Chemical,Organic and Bio-Fertilizers Application on Bell Pepper, <Emphasis Type="Italic">Capsicum annuum</Emphasis> L. and Biological Parameters of <Emphasis Type="Italic">Myzus persicae</Emphasis> (Sulzer) (Hem.: Aphididae)

Myzus persicae (Sulzer) is a polyphagous aphid that causes chlorosis, necrosis, stunting, and reduce growth rate of the host plants. In this research, the effects of Zinc sulfate and vermicompost (30%), Bacillus subtilis, Pseudomonas fluorescens, Glomus intraradices, G. intraradices × B. subtilis, and G. intraradices × P. fluorescens compared to control was investigated on the growth characters of Capsicum annuum L. and biological parameters of M. persicae. Different fertilizers caused a significant effect on growth characters of C. annuum and biological parameters of M. persicae. The highest plant growth was observed on Zinc sulfate and B. subtilis treated plants, and the lowest was on control. Increase in the amount of specific leaf area (SLA) (0.502 mm² mg^?1) was significantly higher in the B. subtilis than other fertilizer treatments. The longest (10.3 days) and the shortest (5.3 days) developmental times of M. persicae nymphs were observed on 30% vermicompost and Zinc sulfate treatments, respectively. The lowest adult longevity periods of M. persicae (11.2 and 11.3 days) were observed on G. intraradices × B. subtilis and 30% vermicompost treatments, respectively, and the longest ones (16.4 days) on Zinc sulfate. The highest rate of nymphal mortality and the lowest amount of nymphal growth index (NGI) were recorded on 30% vermicompost. The nymphs reared on Zinc sulfate treatment had the lowest rate of nymphal mortality and the highest amount of NGI. Thus, amending the soil with 30% vermicompost had a significantly negative effect on the biological parameters of M. persicae that can be used as an ecological control tactic for this pest.     

Design,Optimization, and Evaluation of a Novel Metronidazole-Loaded Gastro-Retentive pH-Sensitive Hydrogel

Floating pH-sensitive chitosan hydrogels containing metronidazole were developed for the eradication of Helicobacter pylori from the stomach. Hydrogels were prepared by crosslinking medium or high molecular weight chitosan in lyophilized solutions containing metronidazole using either citrate or tripolyphosphate (TPP) salts at 1% or 2% concentration. A 2³ factorial design was developed to study the influence of formulation parameters on the physical characteristics of the prepared hydrogels. The interaction between hydrogel components was investigated. The morphology of the prepared hydrogels was inspected and their percentage swelling, release pattern, and moisture content were evaluated. The results revealed the absence of interaction between hydrogel components and their highly porous structure. Percentage swelling of the hydrogels was much higher, and drug release was faster in gastric pH compared with intestinal pH. The formula prepared using 2% high molecular weight chitosan and 2% TPP significantly swelled (700%) within the first 4 h and released the loaded drug over a period of 24 h. Its moisture content was not affected by storage at high relative humidity. Therefore, this formula was selected to be tested in dogs for its gastric retention (using X-ray radiography) and efficacy in the eradication of H. pylori (using histopathological and microbiological examination). The results revealed that the prepared hydrogel formula was retained in dog stomach for at least 48 h, and it was more effective against H. pylori than the commercially available oral metronidazole tablets (Flagyl®).     

<Emphasis Type="Italic">In Vitro</Emphasis> Anti-inflammatory and Antimicrobial Activities of Azithromycin After Loaded in Chitosan- and Tween 20-Based Oil-in-Water Macroemulsion for Acne Management

The objectives of the current investigation are (1) to prepare and characterize (particle size, surface charge (potential zeta), surface morphology by transmission electron microscopy, drug content, and drug release) the azithromycin (AZM, 100 mg)-loaded oil-in-water (o/w) macroemulsion, (2) to assess the toxicity of macroemulsion with or without AZM using RBC lysis test in comparison with AZM in phosphate buffer solution of pH 7.4, (3) to compare the in vitro antimicrobial activity (in Escherichia coli using zone inhibition assay) of AZM-loaded macroemulsion with its aqueous solution, and (4) to assess the in vitro anti-inflammatory effect (using egg albumin denaturation bioassay) of the AZM-loaded macroemulsion in comparison with diclofenac sodium in phosphate buffer solution of pH 7.4. The AZM-loaded macroemulsion possessed the dispersed oil droplets with a mean diameter value of 52.40?±?1.55 μm. A reversal in the zeta potential value from negative (?2.16?±?0.75 mV) to positive (+6.52?±?0.96 mV) was noticed when AZM was added into the macroemulsion. At a 1:5 dilution ratio, 2.06?±?0.03 mg of drug was released from macroemulsion followed by 1.01?±?0.01 and 0.25?±?0.08 mg, respectively, for 1:10 and 1:40 dilution ratios. Antimicrobial activity maintenance and significant reduction of RBC lysis property were noticed for AZM after loaded in the macroemulsion. However, an increment in the absorbance values for emulsion-treated samples in comparison to the control samples was noticed in the anti-inflammatory test. This speculates the potential of the AZM-loaded emulsion to manage inflammatory conditions produced at Acne vulgaris.