A Potential Inhibitory Profile of Liver CD68+ Cells during HCV Infection as Observed by an Increased CD80 and PD-L1 but Not CD86 Expression

AimThe lack of potent innate immune responses during HCV infection might lead to a delay in initiating adaptive immune responses. Kupffer cells (KCs) and liver-infiltrating monocytes/macrophages (CD68⁺ cells) are essential to establish effective anti-HCV responses. They express co-stimulatory molecules, CD80 and CD86. CD86 upregulation induces activator responses that are then potentially regulated by CD80. The relative levels of expression of CD80, CD86 and the inhibitory molecule, PD-L1, on CD68⁺ cells modulate T cell activation. A few studies have explored CD80 and PD-L1 expression on KCs and infiltrating monocytes/macrophages in HCV-infected livers, and none investigated CD86 expression in these cells. These studies have identified these cells based on morphology only. We investigated the stimulatory/inhibitory profile of CD68⁺ cells in HCV-infected livers based on the balance of CD80, CD86 and PD-L1 expression.MethodsCD80, CD86 and PD-L1 expression by CD68⁺ cells in the lobular and portal areas of the liver of chronic HCV-infected (n = 16) and control (n = 14) individuals was investigated using double staining immunohistochemistry.ResultsThe count of CD68⁺ KCs in the lobular areas of the HCV-infected livers was lower than that in the control (p = 0.041). The frequencies of CD68⁺CD80⁺ cells and CD68⁺PD-L1⁺ cells in both lobular and total areas of the liver were higher in HCV-infected patients compared with those in the control group (p = 0.001, 0.031 and 0.007 respectively). Moreover, in the lobular areas of the HCV-infected livers, the frequency of CD68⁺CD80⁺ cells was higher than that of CD68⁺CD86⁺ and CD68⁺PD-L1⁺ cells. In addition, the frequencies of CD68⁺CD80⁺ and CD68⁺CD86⁺ cells were higher in the lobular areas than the portal areas.ConclusionsOur results show that CD68⁺ cells have an inhibitory profile in the HCV-infected livers. This might help explain the delayed T cell response and viral persistence during HCV infection.     

Root colonization and growth enhancement in wheat and tomato by rhizobacteria isolated from the rhizoplane of grasses

Rhizobacteria isolated from the rhizoplane of grasses growing at the Nylsvlei Nature Reserve in South Africa were investigated for growth promotion and root colonization in wheat (Triticum aestivum L.) and tomato (Lycopersicon esculentum Mill.) under greenhouse and microplot field conditions. The identities of the isolates were determined by means of 16S rRNA gene sequencing as Bacillus simplex (KBS1F-3), Bacillus megaterium (NAS7-L), Bacillus cereus (KFP9-F) and Paenibacillus alvei (NAS6G-6). The three Bacillus strains were isolated from the perennial grass Themeda triandra while the Paenibacillus strain was isolated from another perennial grass Sporobolus fimbriatus. Enhanced plant shoot and root weight in wheat was achieved by single inoculation with three of the isolates whereas no significant increase was observed in root length. Combined inoculation of Paenibacillus alvei (NAS6G-6) and Bacillus cereus (KFP9-F) on wheat resulted in significant increase in these parameters. Single inoculations of Bacillus simplex (KBS1F-3) and Bacillus cereus (KFP9-F) resulted in significant increase in root and shoots fresh weight, root dry weight and total root length in tomatoes. Indoleacetic acid production, phosphate solubilization and siderophore secretion were studied as possible mechanisms by which the bacterial isolates enhanced plant growth. Root colonization was studied by means of spontaneous rifampicin resistant strains of the wild type isolates. Except for B. megaterium (NAS7-L), the rest of the isolates colonized the roots efficiently resulting in concentrations of 10⁶–10⁸ cfu g⁻¹ root. The root colonization of Bacillus simplex (KBS1F-3) and Paenibacillus alvei (NAS6G-6) was visualized by confocal scanning laser microscope (CSLM) after successful transformation of the isolates with the pNF8 plasmid carrying the gene for the green fluorescent protein (gfp).     

Mixed Infection of Toe Nail Caused by Trichosporon asahii and Rhodotorula mucilaginosa

Mycopathologia - Trichosporon asahii and Rhodotorula mucilaginosa are important fungal species causing disseminated disease in immunocompromised patients. Onychomycosis prevalence rate ranges from...     

Interactions between dung beetles (Coleoptera: Scarabaeidae) and the arbovirus vector Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae)

Abstract  The potential for dung beetles to reduce populations of the biting midge and arbovirus vector Culicoides brevitarsis in bovine dung was studied in the Hunter Valley, New South Wales (NSW) between 1999 and 2003 using natural populations of insects. Preliminary work to develop experimental procedures showed that: a few C. brevitarsis could survive in buried dung; dung beetles and C. brevitarsis coming to dung were unaffected by a background of shade-cloth used experimentally to prevent dung burial; the most abundant dung beetle, Onthophagus gazella L. and C. brevitarsis oviposition occurred concurrently in the first 2 d after dung deposition, and the potential for interaction between dung beetles and C. brevitarsis was greatest in open pasture adjacent to trees where cattle congregate at night. Laboratory experiments on dung burial showed that C. brevitarsis numbers decreased as numbers of dung beetles increased or as the dry weight of dung decreased due to burial. This was seldom reflected in the field where, although significant burial occurred experimentally in 9 of 20 trials over 3 years, a significant decline in C. brevitarsis numbers attributable to burial only occurred once. C. brevitarsis numbers in the field were lower in unburied dung in 70% of trials. Differences were significant twice and were considered the result of dung disturbance. In the laboratory, decreasing numbers of C. brevitarsis were related to three characteristics of disturbance: the flattening, spreading and reduction in wet weight of the dung. Evidence of C. brevitarsis activity throughout coastal NSW suggests that, while C. brevitarsis numbers may be modified by dung beetles, the interaction is insufficient to prevent their increase, spread and ability to transmit viruses to livestock.     

The antibiotic ciprofloxacin alters the growth,biochemical composition,and antioxidant response of toxin-producing and non-toxin-producing strains of Microcystis

The increased production, consumption, and release of antibiotics account for their frequent contamination of aquatic ecosystems and detection in different biological matrices. Several antibiotics affect non-target organisms such as algae, cyanobacteria, zooplankton, and fish, making investigations on them very crucial for the health and maintenance of biodiversity. The impact of broad-spectrum antibiotics like ciprofloxacin (CPX) on toxin-producing and non-toxin-producing cyanobacteria has been poorly investigated. Therefore, the present study investigated the physiological and toxicological effects of CPX on Microcystis aeruginosa EAWAG 198, Microcystis aeruginosa LE3, and Microcystis flos-aquae UTEX-LB 2677. CPX caused a significant (p < 0.05) decrease in the cell densities and chlorophyll-a of the three strains. The antibiotic caused oxidative stress in all the strains, as demonstrated by a significant rise in the levels of intracellular hydrogen peroxide (H₂O₂) of the treated cultures at 96 h post-exposure. Lipid peroxidation and the activity of the antioxidant enzyme—peroxidase (POD) and glutathione-S-transferase (GST)—of the cultures were significantly (p < 0.05) altered. Exposure to CPX generally stimulated the production of biomolecules such as total proteins, lipids, and total carbohydrates as a function of increasing exposure concentration. The exception to the general trend was M. aeruginosa EAWAG 198, a non-toxin-producing strain, which suffered a significant decline in carbohydrate content during exposure to CPX. This study revealed that environmentally relevant levels of CPX could alter the population dynamics, photosynthesis, biochemical composition, and the general physiology of Microcystis species/strains in aquatic ecosystems.

     

Characterization of Afp1, an antifreeze protein from the psychrophilic yeast Glaciozyma antarctica PI12

The psychrophilic yeast Glaciozyma antarctica demonstrated high antifreeze activity in its culture filtrate. The culture filtrate exhibited both thermal hysteresis (TH) and ice recrystallization inhibition (RI) properties. The TH of 0.1 °C was comparable to that previously reported for bacteria and fungi. A genome sequence survey of the G. antarctica genome identified a novel antifreeze protein gene. The cDNA encoded a 177 amino acid protein with 30 % similarity to a fungal antifreeze protein from Typhula ishikariensis. The expression levels of AFP1 were quantified via real time-quantitative polymerase chain reaction (RT-qPCR), and the highest expression levels were detected within 6 h of growth at ?12 °C. The cDNA of the antifreeze protein was cloned into an Escherichia coli expression system. Expression of recombinant Afp1 in E. coli resulted in the formation of inclusion bodies that were subsequently denatured by treatment with urea and allowed to refold in vitro. Activity assays of the recombinant Afp1 confirmed the antifreeze protein properties with a high TH value of 0.08 °C.     

Effects of organosulfurs, isothiocyanates and vitamin C towards hydrogen peroxide-induced oxidative DNA damage (strand breaks and oxidized purines/pyrimidines) in human hepatoma cells

The aim of this study was to evaluate the effects of organosulfurs, isothiocyanates and vitamin C towards hydrogen peroxide-induced DNA damage (DNA strand breaks and oxidized purines/pyrimidines) in human hepatoma cells (HepG2), using the Comet assay. Treatment with hydrogen peroxide (H(2)O(2)) increased the levels of DNA strand breaks and oxidized purine and pyrimidine bases, in a concentration and time dependent manner. Organosulfur compounds (OSCs) reduced DNA strand breaks induced by H(2)O(2). In addition, OSCs also decreased the levels of oxidized pyrimidines. However, none of the OSCs tested reduced the levels of oxidized purines. Isothiocyanates compounds (ITCs) and vitamin C showed protective effects towards H(2)O(2)-induced DNA strand breaks and oxidized purine and pyrimidine bases. The results indicate that removal of oxidized purine and pyrimidine bases by ITCs was more efficient than by OSCs and vitamin C. Our findings suggest that OSCs, ITCs and vitamin C could exert their protective effects towards H(2)O(2)-induced DNA strand breaks and oxidative DNA damage by the free radical-scavenging efficiency of these compounds.     

A simple culture method for epithelial stem cells derived from human hair follicle

The challenge arises among researchers when hair follicle stem cells (HFSCs) derived from a human hair follicle remain poorly expanded in defined culture medium. In this study, we isolated the HFSCs and they became confluent after 10 days of cultivation. Comparing the viability of HFSCs cultured in defined keratinocytes serum free medium (KSFM) in a coated plate and CnT07 medium in an uncoated plate, the number of HFSCs cultured in CnT07 was significantly higher at days 2, 4, 6 and 8 (P=0.004). The population doubling time of HFSCs was 21.48±0.44 hours in non-coated plates with CnT07 and 30.73±0.75 hours in coated plates with KSFM. Our primary HFSC cultures were positive for CD200 and K15 with brownish color. Flow cytometry analysis showed that the percentage of HFSCs expressing CD200 and K15 were 65.20±3.16 and 72.07±6.62 respectively. After reaching 100% confluence, the HFSCs were differentiated into an epidermal layer in vitro using CnT02-3D defined media. HFSCs were differentiated into an epidermal layer after 2 weeks of induction. Involucrin- and K6-positive cells were detected in the differentiated epidermal layer. This method is a simple technique for HFSC isolation and has a lower cost of processing and labor, and it represents a promising tool for skin tissue engineering.