Identification of two major direct repeat unit clusters, 8i and 11ce, among methicillin resistant Staphylococcus aureus strains: the emergence of novel dru types and repeats.

BACKGROUND: The changing epidemiology and decreasing susceptibility to first-line antibiotics, such as vancomycin and linezolid, leave clinicians with few therapeutic options for MRSA infections. This study aimed to conduct an epidemiology study and characterize MRSA isolates. METHODS: A total of 150 MRSA isolates were collected from clinical specimens. Antimicrobial susceptibility was determined using the disk diffusion method. Resistance and major virulence genes were screened using the polymerase chain reaction. The SCCmec and dru typing were used to conduct molecular epidemiology. The BioNumerics tandem-repeat sequence typing plug-in tool was utilized for dru type cluster analysis. We constructed a minimum spanning tree using the similarity matrix of the DSI model. RESULTS: We discovered 24 dru types among the 55 dru sequenced MRSA isolates. Additionally, eight new dru types were discovered and added to the dru typing database. Two dru clusters (8i, 11ce) and nine single dru types were identified in 55 dru sequenced MRSA isolates. The two dru clusters, 8i and 11ce, accounted for 46 MRSA isolates (83.63%). The most common one of the nine singles dru types in this study was dt9bd, which belonged to the SCCmec types of IX. CONCLUSIONS: Given that two clusters account for the majority of strains in our study, we can conclude that the genetic origin of these strains is the same. Therefore, the spread of these strains can be prevented with effective MRSA monitoring in hospitals and communities.

Efficacy of dietary supplemental insoluble fibrous materials in ameliorating adverse effects of coccidial challenge in broiler chickens.

The current experiment was designed to examine effects of dietary supplemental sunflower hulls (SH) and rice hulls (RH) on growth performance, carcass traits, intestinal morphology, lesion score and oocyst shedding in broiler chickens exposed to coccidial challenge. A total of 540 broiler chickens (Ross 308) were assigned to six dietary treatments based on a factorial arrangement (2 × 3) across 1-14, 14-28 and 28-42-d periods. Experimental treatments consisted of broiler chickens without or with coccidial challenge each offered with three different diets: a basal diet or basal diet supplemented with either RH or SH at 40 g/kg diet, respectively. Infection with Eimeria impaired daily weight gain (DWG) and feed conversion ratio (FCR) of broiler chickens during growing period (p < 0.05) while supplementation of SH or RH reduced the adverse effect of coccidiosis so that birds had similar DWG to those fed the basal diet without infection. However, only dietary SH improved the FCR of broilers challenged with coccidiosis. Regardless of coccidial challenge, dietary access to insoluble fibre improved performance of broilers across the growing period (p < 0.05); however, this effect was not observed during the entire rearing period. Relative weights of liver and pancreas were increased in birds subjected to coccidial challenge on d 21 of age (p < 0.05). Moreover, relative weights of the intestinal segments were enhanced (p < 0.05). Furthermore, gizzard weights were higher in birds receiving diets added with fibre (p < 0.05). Infection with coccidiosis decreased villus height and villus height to crypt depth ratio in duodenum of broilers which received the basal diet compared with those fed the same feed without coccidial challenge (p < 0.05). However, supplemental SH could decrease the negative effect of infection on the noted intestinal morphometric attributes. Similarly, a marked reduction was observed for lesion score and faecal oocyst excretion of challenged broilers fed on dietary supplemental fibre (p < 0.05). In conclusion, supplementation of insoluble fibre could ameliorate negative effects of coccidial challenge on DWG of broiler chickens and inclusion of SH in diet of birds exposed to Eimeria infection could be recommended.

Transgenerational sublethal effects of abamectin and pyridaben on demographic traits of Phytonemus pallidus (Banks) (Acari: Tarsonemidae).

In addition to determining the lethal effects, identifying sublethal effects of a pesticide is crucial to understanding the total impact a pesticide may have on a pest population. We determined the sublethal effects the two pesticides, abamectin and pyridaben, have on the cyclamen mite, Phytonemus pallidus (Banks) (Acari: Tarsonemidae)-a major pest of strawberry. Demographic traits of the P. pallidus progeny (F1 generation) produced by parents (F0 generation) treated with a low lethal concentration (LC15) of abamectin and pyridaben were assessed using the age-stage, two-sex life table theory. The total longevity of the F1 generation (males = 10.78 days; female = 14.35 days) was the shortest in the progeny of the abamectin treated parents, differing significantly from the progeny of mites treated with pyridaben (males = 11.50 days, females = 15.63 days), and the control population (males = 13.50 days, females = 17.81 days). The intrinsic rates of increase (r) and the finite rates of increase (λ) of the progeny of abamectin (r = 0.0854 day-1, λ = 1.0891 day-1) and pyridaben (r = 0.0951 day-1, λ = 1.0997 day-1) treated parents were significantly lower than in the control mites (r = 0.1455 day-1, λ = 1.1567 day-1). The lowest fecundity (5.35 eggs/female), occurred in F1 female offspring of parents treated with LC15 concentrations of abamectin, which was significantly lower than in the pyridaben (6.11 eggs/female) and control treatments (11.45 eggs/female). Transgenerational sublethal effects of abamectin and pyridaben in P. pallidus can be effectively used to for optimizing IPM programs against this pest on strawberries.

Analyzing Sunn pest resistance in bread wheat genotypes using phenotypic characteristics and molecular markers.

Sunn pest is one of the most destructive insects in the western and central parts of Asia causing severe reductions of wheat yield and flour quality. Therefore, an effort was undertaken to find effective resistance by analyzing genetic variation among 25 wheat genotypes artificially infested in field-cages as well as using start codon targeted (SCoT) polymorphism and inter- retrotransposon amplified polymorphism (IRAP) markers. High variation was revealed amongst genotypes with Sunn pest resistance characteristics including Bayat, Bezostaya, Sayson, Line93, Line120, Rashagol, Golsepi and AarasGolsoor, which were classified as resistant to moderately resistant. SCoTs and IRAPs were determined as efficient markers for studying genetic diversity. The non-parametric Kruskal-Wallis test was conducted to evaluate the effect of specific SCoT and IRAP amplicons on Sunn pest resistance characteristics for wheat genotypes. The stepwise regression analysis exhibited seven informative SCoTs and IRAPs explaining the highest resistance characteristics variation ranging from 25.7-50.1 to 17.6-40.1, respectively. The relationship between resistance of genotypes and informative SCoT and IRAP amplicons was found based on canonical discriminant analysis showing the capacity of informative markers for functional marker selection method and screening the wheat germplasms for Sunn pest resistance characteristics.

Demographic characteristics and population projection of Phytonemus pallidus fragariae reared on different strawberry cultivars.

The strawberry mite, Phytonemus pallidus fragariae (Banks) (Acari: Tarsonemidae), is one of the most important pests of greenhouse grown strawberry plants. Field grown strawberries may also be infested by the pest in high humid conditions. Life tables give the most comprehensive description of the development, survival, stage differentiation, reproduction and consequently population growth of a population, and thus it is an important base of population ecology and pest management. In this study, to provide a comprehensive evaluation of an ecology-based and cost-effective control program, life history and demographic parameters of the strawberry mite were studied. The experiment was conducted under laboratory conditions providing 20 ± 1 °C, 80 ± 10% RH and L16:D8 photoperiod. The data were analyzed based on the age-stage, two-sex life table theory. The population parameters net reproduction rate (R0 = 6.14 offspring), intrinsic rate of increase (r = 0.1317 day-1), and finite rate of increase (λ = 1.1407 day-1) on cv. Aromas were lower than those on the other cultivars tested. Based on the population characteristics, Aromas is a less favorable cultivar for the population growth of strawberry mite.

Effect of various fiber types and choice feeding of fiber on performance, gut development, humoral immunity, and fiber preference in broiler chicks.

Two experiments were conducted to investigate the effect of fibrous materials with one single diet or by choice feeding on performance, intestinal morphology, immunity, and fiber preference in broiler chicks. In experiment 1, 240-day-old chicks (Ross 308) were assigned to one of 4 treatments, comprising 5 replicates per treatment in a completely randomized design. Dietary treatments included: a basal diet (control) or 30 g/kg sugar beet pulp (SBP), 30 g/kg rice hull (RH), or 30 g/kg equal combination of them (SBP/RH) added to the basal diet. Results showed SBP and SBP/RH impaired daily weight gain (DWG) in the growing period compared with control (P < 0.05). Additionally, chickens that received SBP had deteriorated FCR across the entire rearing period (P < 0.05). In comparison to control and SBP, supplementing SBP/RH significantly increased antibody titer against Newcastle disease virus (NDV; P < 0.05) at 23 d of age. Furthermore, SBP reduced duodenal and ileal villus height compared with control at 21 d of age. In experiment 2, a total of 240 chicks were allotted to 4 experimental treatments of feeding: 1) control; or choice feeding between 2) control and SBP (C-SBP); 3) control and RH (C-RH); 4) control and SBP/RH (C- SBP/RH). Results indicated that chicks had a tendency to use separate sources of fiber. RH was consumed lower than C-SBP/RH and C-SBP in starter and growing periods, respectively (P < 0.05). Chickens choice fed RH and SBP/RH had greater daily feed intake than control across 14 to 28 d of age (P < 0.05). However, DWG reduced in all fiber fed birds (P < 0.05) and resulted in impaired FCR in broilers of the C-SBP group (P < 0.05). In addition, choice feeding of SBP/RH increased antibody titer against NDV as compared with control and SBP (P < 0.05). In conclusion, fiber inclusion in both experiments impaired growth performance but an equal combination of fiber improved immunity. In addition, broilers had a tendency to use separate sources of fiber.

Hybrid gelatin-sulfated alginate scaffolds as dermal substitutes can dramatically accelerate healing of full-thickness diabetic wounds.

Diabetic foot ulcers (DFUs) are defined as chronic and non-healing wounds that cause skin disorders. Here, we introduce a novel biodegradable gelatin/sulfated alginate hybrid scaffold as a dermal substitute to accelerate the healing of full-thickness diabetic ulcers in a diabetic mouse model. The hybrid scaffold possessing different weight ratios of sulfated alginate, from 10 % up to 50 %, were prepared through chemical crosslinking by carbodiimide chemistry and further freeze-drying. Based on the in vitro cytotoxicity experiments, the hybrid scaffolds not only showed no cytotoxicity, but the cell growth also dramatically increased by increasing the sulfated alginate content. Finally, the pathology of hybrid scaffolds as the dermal substitutes for healing of full-thickness diabetic wounds showed the more appropriate formation of epidermal layer, more homogeneous distribution of collagenous tissue and lower penetration of immune cells for the hybrid scaffolds-treated wounds.

Induction of resistance to Myzus persicae-nicotianae in Cucumber mosaic virus infected tobacco plants using silencing of CMV-2b gene.

Aphids such as tobacco aphid Myzus persicae-nicotianae, are among the most important plant viral vectors and plant viruses encode genes to interact with their vectors. Cucumber mosaic virus (CMV) encodes 2b protein as a suppressor of plant immune and it plays a vital role in CMV accumulation and susceptibility to aphid vectors. In this study, the resistance of tobacco plants (Nicotiana tabacum) to M. p. nicotianae was evaluated by silencing of 2b in CMV-infected plants. However, the pFGC-C.h silencing gene construct was transiently expressed using Agrobacterium tumefacience, LBA 4404 in tobacco leaves, and four days later, the plants were mechanically inoculated by CMV (Kurdistan isolate), and then, 15 days post-inoculation 1 nonviruliferous aphid was placed on each leaf for evaluation of resistance to M. p. nicotianae. To evaluate the tobacco plants resistance and susceptibility to M. p. nicotianae, the number of aphids existent per tobacco leaf, life table and, demographic parameters were recorded and used as a comparison indicator. The obtained results were analyzed using the age-stage, two-sex life table. The highest number of aphids was recorded on the control CMV-infected plants, while the lowest number on CMV infected leaves expressing CMV-2b silencing construct (pFGC-C.h). The obtained data revealed the lowest rate for all of intrinsic rate of natural increase (rm) (0.246/day), the rate of reproduction (r0) (17.04 females/generation), and finite rate of increase (λ) (1.279/day), on the pFGC-C.h treatment. The maximum generation time (T) (11.834 days) was observed on (V) treatment. However, the collected data revealed induction of resistance to tobacco aphids by silencing of CMV-2b in CMV infected plants.

Determination of Virulence Factors and Resistance Profile of Methicillin-Resistant Staphylococcus aureus Strains among Different Types of spa, agr, and SCCmec.

In order to restrict the spread of methicillin-resistant S. aureus (MRSA) in hospitals, it is necessary to characterize isolates rapidly and precisely. The objective of this study was to determine virulence factors and resistance profiles of MRSA strains among spa, agr, and SCCmec types. In total, 55 MRSA isolates were collected from clinical specimens. The MRSA isolates were characterized by antimicrobial susceptibility testing, virulence genes, agr typing, spa typing, and SCCmec typing. According to our findings, all MRSA strains were resistant to cefoxitin; 88% and 86.7% of which were resistant to erythromycin and clindamycin, respectively. Type II agr was predominant with 54.54% frequency. Among 27 different spa types, type t030 was most frequently (25.45%). Most MRSA isolates (63.3%) were SCCmec type III. The pvl and tst genes were found in 25.3% and 32.7% of MRSA isolates, respectively. Among the MRSA strains, ermA, ermB, and ermC were present in 50%, 33.3%, and 57.3% of cases, respectively. In addition, 43 of the 55 MRSA strains (78%) harbored aminoglycoside resistance genes. The results of our study revealed that the MRSA rate in our region is dramatically high. Better infection control guidelines in hospitals, as well as ongoing epidemiological surveillance studies, could be strongly suggested for effective prevention of the spread of MRSA to inpatients.

Fabrication and In Vitro Evaluation of A Chondroitin Sulphate-Polycaprolactone Composite Nanofibrous Scaffold for Potential Use in Dermal Tissue Engineering.

OBJECTIVE: Poly(ε-caprolactone) (PCL) has considerable mechanical and biological properties that make it a good candidate for tissue engineering applications. PCL alongside proteins and polysaccharides, like gelatin (GEL) and chondroitin sulphate (CS), can be used to fabricate composite scaffolds that provide mechanical and biological requirements for skin tissue engineering scaffolds. The aim of this study was fabricating novel composite nanofibrous scaffold containing various ratios of GEL/CS and PCL using co-electrospinning process. MATERIALS AND METHODS: In this experimental study, PCL mixed with a GEL/CS blend has limitations in miscibility and the lack of a common solvent. Here, we electrospun PCL and GEL/CS coincide separately on the same drum by using different nozzles to create composite nanofibrous scaffolds with different ratios (2:1, 1:1 and 1:2) of GEL to CSPCL, and we mixed them at the micro/nanoscale. Morphology, porosity, phosphate-buffered saline (PBS) absorption, chemical structure, mechanical property and in vitro bioactivity of the prepared composite scaffolds were analysed. RESULTS: Scanning electron microscopy (SEM) images showed beadless nanofibres at all ratios of GEL to CS-PCL. The composite scaffolds (2:1, 1:1 and 1:2) had increased porosity compared to the PCL nanofibrous scaffolds, in addition to a significant increase in PBS absorption. The mechanical properties of the composite scaffolds were investigated under different conditions. The results demonstrated that all of the composite specimens had better strength when compared with the GEL/CS nanofibres. The increase in PCL ratio led to an increase in tensile strength of the nanofibres. Human dermal fibroblasts (HDF) were cultured on the fabricated composite scaffolds and evaluated by 3-(4,5-dimethylthiazol- 2-yl)-5-(3 carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) analysis and SEM. The results showed the bioactivity of these nanofibres and the potential for these scaffolds to be used for skin tissue engineering applications. CONCLUSION: The fabricated co-electrospun composite scaffolds had higher porosity and PBS absorption in comparison with the PCL nanofibrous scaffolds, in addition to significant improvements in mechanical properties under wet and dry conditions compared to the GEL/CS scaffold.

Multilayered 3-D nanofibrous scaffold with chondroitin sulfate sustained release as dermal substitute.

Electrospun nanofibers for skin tissue engineering applications face two main challenges. The low thickness of electrospun mats is the main reason for their weak load-bearing performance at clinical applications and limited cell penetration due to their small pore sizes. We have developed multi-layered nanofibrous 3D (M3DN) scaffolds comprising gelatin, polyvinyl alcohol, and chondroitin sulfate (CS) by an electrospinning method and attaching three electrospun layers via ethanol to cause interface fibers to come in contact with each other. Prepared M3DN scaffolds revealed a sustained CS release profile. The improved mechanical performance, stable release of CS, and penetration capability of the cells and blood vessels through the spaces between layers in the prepared multi-layered nanofibrous scaffolds demonstrate their potential applications in response to the increasing demand for replacement of damaged dermis. The results of animal studies on the dorsal skin of Rat with full-thickness wounds have shown that the reconstruction of full-thickness skin lesions is significantly higher for M3DN scaffolds than a control group (treated with sterile gauze). The amount of epithelization, collagen arrangement, and inflammatory cells (acute and chronic) has been investigated, and their associated results demonstrated that M3DN scaffolds have great potential for full-thickness wound restoration.

Gastrointestinal symptoms and the severity of COVID-19: Disorders of gut-brain interaction are an outcome.

BACKGROUND: Many of the studies on COVID-19 severity and its associated symptoms focus on hospitalized patients. The aim of this study was to investigate the relationship between acute GI symptoms and COVID-19 severity in a clustering-based approach and to determine the risks and epidemiological features of post-COVID-19 Disorders of Gut-Brain Interaction (DGBI) by including both hospitalized and ambulatory patients. METHODS: The study utilized a two-phase Internet-based survey on: (1) COVID-19 patients' demographics, comorbidities, symptoms, complications, and hospitalizations and (2) post-COVID-19 DGBI diagnosed according to Rome IV criteria in association with anxiety (GAD-7) and depression (PHQ-9). Statistical analyses included univariate and multivariate tests. RESULTS: Five distinct clusters of symptomatic subjects were identified based on the presence of GI symptoms, loss of smell, and chest pain, among 1114 participants who tested positive for SARS-CoV-2. GI symptoms were found to be independent risk factors for severe COVID-19; however, they did not always coincide with other severity-related factors such as age >65 years, diabetes mellitus, and Vitamin D deficiency. Of the 164 subjects with a positive test who participated in Phase-2, 108 (66%) fulfilled the criteria for at least one DGBI. The majority (n = 81; 75%) were new-onset DGBI post-COVID-19. Overall, 86% of subjects with one or more post-COVID-19 DGBI had at least one GI symptom during the acute phase of COVID-19, while 14% did not. Depression (65%), but not anxiety (48%), was significantly more common in those with post-COVID-19 DGBI. CONCLUSION: GI symptoms are associated with a severe COVID-19 among survivors. Long-haulers may develop post-COVID-19 DGBI. Psychiatric disorders are common in post-COVID-19 DGBI.

Characterization of Plasmid-Mediated Quinolone Resistance and Serogroup Distributions of Uropathogenic Escherichia coli among Iranian Kidney Transplant Patients.

INTRODUCTION: Urinary tract infection (UTI) is one of the most frequent infections in kidney transplant patients (KTPs). This infection is mainly caused by uropathogenic Escherichia coli (UPEC). Plasmid-mediated quinolone resistance (PMQR) was also increasingly identified in UPEC. This study proposed to investigate the frequency of quinolone-resistance plasmid genes and the O-antigen serogroup among UPEC isolated from KTPs and non-KTP with UTI. METHODS: Totally, 114 UPEC isolates from 49 KTPs and 65 non-KTPs patients diagnosed with an UPEC-associated UTI were obtained from June 2019 to December 2019 at three laboratory centers in Isfahan, Iran. The isolates were confirmed through phenotypic and genotypic methods. Moreover, the antimicrobial susceptibility test to nalidixic acid, ciprofloxacin, norfloxacin, and ofloxacin was performed using a disk diffusion method. The presence of the qnr gene as well as the serogroup distribution was identified using the PCR method. RESULT: According to data, the distribution of O1, O2, O4, O16, and O25 serogroups were 3.5%, 2.6, 3.5, 3.5, and 20.2%, respectively. Antibiotic susceptibility pattern revealed that the highest and lowest resistance rates were to nalidixic acid (69.3%) and norfloxacin (43.9%), respectively. Also, the frequency of qnrS and qnrB genes were 33.3% and 15.8%, respectively, while none of the isolates was found to be positive for the qnrA gene. There was no significant association between the presence of qnr genes and higher antibiotic resistance. CONCLUSION: This study recognized that the qnrS gene, O25 serotype, and resistance to nalidixic acid had the highest frequencies in UPEC strains isolated from UTI patients.

Evaluation of the susceptibility of the pea aphid, Acyrthosiphon pisum, to a selection of novel biorational insecticides using an artificial diet.

An improved technique was developed to assay the toxicity of insecticides against aphids using an artificial diet. The susceptibility of the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphidoidea) was determined for a selection of novel biorational insecticides, each representing a novel mode of action. Flonicamid, a novel systemic insecticide with selective activity as feeding blocker against sucking insects, showed high toxicity against first-instar A. pisum nymphs with an LC(50) of 20.4 microg/ml after 24 h, and of 0.24 microg/ml after 72 h. The toxicity was compared with another feeding blocker, pymetrozine, and the neonicotinoid, imidacloprid. In addition, four insect growth regulators were tested. The chitin synthesis inhibitor flufenoxuron, the juvenile hormone analogue pyriproxyfen, and the azadirachtin compound Neem Azal-T/S showed strong effects and reduced the aphid population by 50% after 3 days of treatment at a concentration of 7-9 microg/ml. The ecdysone agonist tested, halofenozide, was less potent. In conclusion, the improved aphid feeding apparatus can be useful as a miniature screening device for insecticides against different aphid pests. The present study demonstrated rapid and strong toxicity of flonicamid, and other biorational insecticides towards A. pisum.

Tough, hybrid chondroitin sulfate nanofibers as a promising scaffold for skin tissue engineering.

Fabrication of gelatin/polyvinyl alcohol/chondroitin sulfate (GEL/PVA/CS) hybrid nanofibrous scaffolds using acetic acid and water as an environmentally friendly solvent system via electrospinning for skin tissue engineering was investigated. Modeling and optimization of the nanofibers were performed using response surface methodology (RSM). The influence of CS ratio on mechanical, physical and biological properties of the nanofibers was studied. PVA was used as a carrier and enhancer of mechanical properties. The mechanical properties of hybrid nanofibers were investigated in dry and wet states. The results showed that in the cross-linked dry state the tensile strength was up to 4 MPa. In the wet state, nanofibers exhibited 200% elongation at break, indicating a toughness behavior which enhances the flexibility for clinical applications. Scanning electron microscope (SEM) confirmed the stability of nanofibrous morphology during degradation up to 21 days. Human dermal fibroblast-green fluorescent protein-positive (HDF-GFP+) cells were cultured on the scaffolds and results showed the appropriate biocompatibility. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was employed to study cell proliferation, and the results confirmed the positive effect of CS ratio on HDF cells attachment as well as proliferation on the nanofibers. Considering the results of in vitro assay, nanofibers containing 15% CS ratio suggested as an optimum CS ratio.

Enhanced chondrogenic differentiation of bone marrow mesenchymal stem cells on gelatin/glycosaminoglycan electrospun nanofibers with different amount of glycosaminoglycan.

Tissue engineering is a new technique to help damaged cartilage treatment using cells and scaffolds. In this study we tried to evaluate electrospun scaffolds composed of gelatin/glycosaminoglycan (G/GAG) blend nanofibers in chondrogenesis of bone marrow-derived mesenchymal stem cells (BMMSCs). Scaffolds were fabricated by electrospinning technique with different concentration of glycosaminoglycan (0%, 5%, 10%, and 15%) in gelatin matrix. BMMSCs were cultured on the scaffolds for chondrogenesis process. MTT assay was done for scaffold's biocompatibility and cells viability evaluation. Alcian blue staining was carried out to determine the release of GAG and reverse transcription polymerase chain reaction (RT-PCR) was done for expression of COL2A1 and also immunocytochemistry assay were used to confirm expression of type II collagen. Scaffold with 15% GAG showed better result for biocompatibility (p =0.02). Scanning electron microscopy (SEM) micrographs showed that MSCs have good attachment to the scaffolds. Alcian blue staining result confirmed that cells produce GAG during differentiation time different from GAG in the scaffolds. Also the results for RT-PCR showed the expression of COL2A1 marker. Immunocytochemistry assay for type II collagen confirm that this protein expressed. Scaffold comprising 15% GAG is better results for chondrogenesis and it can be a good applicant for cartilage tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 38-48, 2019.

Electrospun polyvinyl alcohol/gelatin/chondroitin sulfate nanofibrous scaffold: Fabrication and in vitro evaluation.

Electrospun nanofibers have attracted a lot of attention in recent years in tissue engineering applications. In this research, novel polyvinyl alcohol/gelatin/chondroitin sulfate (PVA/GE/Cs) nanofibrous scaffolds using non-carcinogen solvent system via electrospinning technique was evaluated. A solvent system containing water and acetic acid was used as a safe solvent system to obtain a homogenous mixture with suitable solvent properties and finally non-toxic nanofibrous scaffolds. The effect of water to the acetic acid ratio in the solvent system (7:3, 6:4, 5:5, 4:6, 3:7) and also polymer concentration (8, 9, 10w/v %) on nanofibers morphology was investigated. The appropriate flow rate and voltage ranges to obtain uniform and bead-free electrospun scaffold were investigated. Effect of different Cs ratio (0, 10, 15 and 20wt%) on solution properties was evaluated. Influence of Cs ratio on chemical, physical and thermal properties of the electrospun scaffolds was studied. The results of cell toxicity indicated that prepared PVA/GE/Cs scaffolds have no cell toxicity. SEM results demonstrated that L929 mouse fibroblast cells have suitable interaction with scaffold surface and also attached and proliferated well on the prepared substrate after 24 and 48h and also have a potential for using in tissue engineering.

Demographic Comparison of the Tetranychus urticae Koch. (Acari: Tetranychidae) Reared on Different Cultivars of Strawberry.

The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an important pest of strawberry (Fragaria × ananassa Duch.) grown in greenhouses and outdoors. In this study, we evaluated the resistance status of five common strawberry cultivars ('Aromas', 'Kurdistan', 'Missionary', 'Paros', and 'Queen Elisa') under laboratory conditions. The developmental times of the preadult and adult stages, total longevity, reproduction, and life table parameters were analyzed according to the age-stage, two-sex life table theory, which provides the most comprehensive description on the survival, stage differentiation, and reproduction of a population. Preadult development was the shortest on Kurdistan and longest on Aromas (17.70 d vs. 21.00 d). The greatest number of oviposition days occurred on Missionary (28.65 d), whereas the fewest were on Queen Elisa (21.58 d). The intrinsic rate of natural increase (r) and finite rate of increase (λ) varied among the cultivars. The highest values were found on Kurdistan (r = 0.1436d-1, λ=1.1544d-1), while the lowest values were on the Aromas cultivar (r = 0.1081d-1, λ=1.1141d-1). The longest mean generation time (T) of T. urticae occurred on Aromas. Based on the results of the present study, the cultivar Aromas was considered the most resistant to T. urticae and least favored strawberry cultivar for the development and reproduction of the mite. Demographic data of twospotted spider mite on these five strawberry cultivars can be used to improve our understanding of the population dynamics of the pest and thereby develop effective pest management strategies against T. urticae in both integrated and organic strawberry production.

Expression of garlic leaf lectin under the control of the phloem-specific promoter Asus1 from Arabidopsis thaliana protects tobacco plants against the tobacco aphid (Myzus nicotianae).

BACKGROUND: To check for correlation between the insecticidal properties and the specificity of lectins, a comparative study was made of the insecticidal activities of two garlic lectins with different biological activities. RESULTS: The insecticidal activity of the garlic (Allium sativum L.) leaf lectin ASAL and bulb lectin ASAII towards the tobacco aphid Myzus nicotianae Blackman was studied using bioassays with transgenic tobacco (Nicotiana tabacum L. cv. Wisconsin 38). Bioassays were started with newborn nymphs of the tobacco aphid. Although during the first 7-8 days when nymphs developed to adults there were no apparent effects, part of the nymphal population was found to develop into winged (alate) forms. Later it became clear that transgenic plants expressing ASAL and ASAII had a significant effect on the reproduction capacity of the resulting adults, with a reduction of up to 40%. Different life table parameters such as prereproductive time, intrinsic rate of natural increase, generation time and doubling time were significantly affected (P < 0.05) in aphids grown on transgenic plant material expressing ASAL and ASAII. CONCLUSION: Bioassays with tobacco plants expressing ASAL and ASAII demonstrated a significant impact on the population growth of M. nicotianae. Therefore, both lectins can be considered as valuable candidate aphid control agents.

Deterrent activity of plant lectins on cowpea weevil Callosobruchus maculatus (F.) oviposition.

A set of 14 plant lectins was screened in a binary choice bioassay for inhibitory activity on cowpea weevil Callosobruchus maculatus (F.) oviposition. Coating of chickpea seeds (Cicer arietinum L.) with a 0.05% (w/v) solution of plant lectins caused a significant reduction in egg laying. Control experiments with heat inactivated lectin and BSA indicated that the observed deterrent effects are specific and require carbohydrate-binding activity. However, no clear correlation could be established between deterrent activity and sugar-binding specificity/molecular structure of the lectins. Increasing the insect density reduced the inhibitory effect of the lectins confirming that female insects are capable of adjusting their oviposition rates as a function of host availability.