Water-resistant Lignin/Poly(vinyl alcohol) Blend Fibers for Removal of Hexavalent Chromium

Lignin is the second most abundant renewable biomass-derived natural resource that has been used to replace traditional petrochemical-based materials. However, fabricating the lignin component into the various forms required for practical application is still challenging. In this work, we fabricated water-resistant lignin/poly(vinyl alcohol) (PVA) blend fibers by wet spinning and glutaraldehyde crosslinking methods. The effect of the lignin/PVA blend ratio and glutaraldehyde crosslinking process on the physicochemical properties of wet-spun lignin/PVA blend fibers were studied using maximum draw ratios, hydrolytic degradation profiles, and mechanical properties. Furthermore, the hexavalent chromium [Cr(VI)] removal behavior of lignin/PVA blend fibers was investigated according to the effect of pH, initial Cr(VI) concentration, and contact time. The wet-spun lignin/PVA blend fiber achieved excellent water stability through glutaraldehyde crosslinking and exhibited notable Cr(VI) adsorption capacity (350.87 mg/g) and good regeneration ability. These findings demonstrate that glutaraldehyde-crosslinked lignin/PVA blend fibers could be promising adsorbents for the remediation of heavy metal species containing textile wastewater.     

The Molecular Biology of the Interactions Between Trichoderma spp., Phytopathogenic Fungi, and Plants

ABSTRACT Trichoderma-based biofungicides are a reality in agriculture, with more than 50 formulations today available as registered products worldwide. Several strategies have been applied to identify the main genes and compounds involved in this complex, three-way cross-talk between the fungal antagonist, the plant, and microbial pathogens. Proteome and genome analysis have greatly enhanced our ability to conduct holistic and genome-based functional studies. We have identified and determined the role of a variety of novel genes and gene-products, including ABC transporters, enzymes and other proteins that produce or act as novel elicitors of induced resistance, proteins responsible for a gene-for-gene avirulent interaction between Trichoderma spp. and plants, mycoparasitism-related inducers, plant proteins specifically induced by Trichoderma, etc. We have transgenically demonstrated the ability of Trichoderma spp. to transfer heterologous proteins into plant during root colonization, and have used green fluorescent protein and other markers to study the interaction in vivo and in situ between Trichoderma spp. and the fungal pathogen or the plant.     

Seroprevalence of Mycobacterium avium subspecies paratuberculosis in Korean black goats (Capra hircus aegagrus)

In total, 582 sera from 116 black goat herds were analyzed by a commercially available ELISA kit to monitor the seroprevalence of Mycobacterium avium subspecies paratuberculosis (Mpt) in Korean black goats (Capra hircus aegagrus). The mean number of goats sampled per herd was 5.11, 4.66, and 5.38 for the northern, central, and southern regions of Korea, respectively. The apparent regional prevalence of Mpt was estimated at 18.2-38.2% and 4.6-15.3% for herds and goats, respectively. The Mpt-positive goats were predominantly detected in the south (n=28), compared to either the northern (n=9) or central (n=11) regions (chi=14.459, P<0.05). Our findings indicate that Mpt is prevalent among the goat population, but regional variation exists.     

Seroprevalence of low pathogenic avian influenza (H9N2) and associated risk factors in the Gyeonggi-do of Korea during 2005-2006

Between November 2005 and March 2006, a total of 253 poultry flocks in the Gyeonggi-do of Korea were examined for seroprevalence against avian influenza (AI) using a hemagglutination inhibition (HI) test and an agar gel precipitation test. No low pathogenic avian influenza (LPAI) virus was isolated from 47 seropositive flocks that lacked clinical signs during sampling. The unadjusted percentage of seroprevalence rates of layer and broiler flocks were not significantly different, i.e., 26% (25/96) and 23% (22/97), respectively. The HI titer of the layers (mean = 89) was higher than the broilers (mean = 36; p < 0.001). A cross-sectional study was conducted for the seroprevalence of LPAI in the layers. Of 7 risk factors, farms employing one or more workers had a higher seropositive prevalence as compared to farms without hired employees (adjusted prevalence OR = 11.5, p = 0.031). Layer flocks older than 400 d had higher seropositivity than flocks younger than 300 d (OR = 4.9, p = 0.017). The farmers recognized at least one of the clinical signs in seropositive flocks, such as decreased egg production, respiratory syndromes, and increased mortality (OR = 2.3, p = 0.082). In a matched case-control study, 20 pairs of case and control flocks matched for type of flock, hired employees, age, and flock size were compared. Frequent cleansing with disinfectants was associated with a decreased risk of seropositivity (OR = 0.2, p = 0.022). Although there was a low statistical association, using a foot disinfectant when entering the building led to a decreased rate of seropositivity (OR = 0.3, p = 0.105).     

Glyoxysomal Nature of Microbodies Complexed with Lipid Globules in Botryosphaeria dothidea

ABSTRACT The glyoxysomal nature of microbodies was determined in Botryosphaeria dothidea hyphae based on morphology and in situ enzyme characteristics by transmission electron microscopy and cytochemistry. Bound by a single membrane, microbodies had a homogeneous matrix and varied in size ranging from 200 to 400 nm in diameter. Microbodies often had crystalline inclusions that consisted of parallel arrays of fine tubules in their matrices. Microbodies and lipid globules were placed in close association with each other, forming microbody-lipid globule complexes in hyphae. The cytochemical activities of catalase and malate synthase were localized in microbodies, showing intense electron density of the organelle. In addition, immunogold labeling detected the presence of catalase in a multivesicular body-like organelle and the cell wall as well as in the matrix and crystalline inclusion of microbodies, supporting the enzyme secretion outward. Meanwhile, isocitrate lyase was localized only in matrices of microbodies. These results suggest that the microbodies complexed with lipid globules in B. dothidea hyphae are functionally defined as glyoxysomes which may enable the fungus to survive latent periods using lipids via the glyoxylate cycle and catalase secretion.     

Effects of temperature on the in vivo and in vitro multiplication of Trypanosoma danilewskyi Laveran et Mesnil.

Temperature directly affected the in vivo and in vitro multiplication of Trypanosoma danilewskyi Laveran et Mesnil. The parasitemia in experimentally infected goldfish (Carassius auratus L.) increased rapidly at 20 degrees C and reached its peak in 3 to 5 weeks post-infection. The multiplication was slower at 10 degrees C. The parasitemia declined after the peak at 20 degrees C. Lowering of temperature of the infected goldfish from 20 degrees C to 10 degrees C slowed multiplication of the parasite. Similarly, raising of temperature of infected fish from 10 degrees C to 20 degrees C resulted in rapid multiplication of the parasite. These were confirmed in the in vitro studies. It is suggested that lower temperature slows the multiplication of the parasites because T. danilewskyi is a parasite of a warm water host (Carassius auratus gibelio Bloch).     

Seroprevalence of leptospirosis in Korean municipal zoo animals

From 2002 to 2005, we collected 118 serum samples from 34 species belonging to 13 families of zoo animals in Korea and determined the prevalence of antibodies for 18 serovars of Leptospira spp. using the microscopic agglutination test (MAT). Twenty-nine (25%) of the serum samples tested were positive for one or more of the serovars. There were no significant differences in relation to genders: 23% and 26% of positives occurring in male and female animals, respectively (P>0.05). However, the seroprevalence for the Leptospira spp. was significantly higher (P<0.05) in herbivores (45%) than in either carnivores (17%) or omnivores (17%). Among the 5 serovars detected in this study, the most common was sejroe (n=27; 87% of all positive reactions). All positive reactions showed low titers (< or = 1:200) and the positives were most frequently detected in 1:25 (58%) and 1:50 (23%) serum dilutions. The highest antibody titer (1:200) was observed for the serovars sejroe (n=1) and bratislava (n=1). We conclude that the exposure of zoo animals to Leptospira spp. is relatively common in Korea and produces low MAT titers, with sejroe being the most commonly encountered serovar.     

Air assisted lamellar keratectomy for the corneal haze model

To standardize the corneal haze model in the resection depth and size for efficient corneal haze development, air assisted lamellar keratectomy was performed. The ex vivo porcine corneas were categorized into four groups depending on the trephined depth: 250 µm (G1), 375 µm (G2), 500 µm (G3) and 750 µm (G4). The stroma was equally ablated at the five measurement sites in all groups. Significant differences were observed between the trephined corneal depths for resection and ablated corneal thickness in G1 (p < 0.001). No significant differences were observed between the trephined corneal depth for resection and the ablated corneal thickness in G2, G3, and G4. The resection percentage was similar in all groups after microscopic imaging of corneal sections. Air assisted lamellar keratectomy (AK) and conventional keratectomy (CK) method were applied to six beagles, after which development of corneal haze was evaluated weekly until postoperative day 28. The occurrence of corneal haze in the AK group was significantly higher than that in the CK group beginning 14 days after surgery. Alpha-smooth muscle actin expression was significantly higher in the AK group (p < 0.001) than the CK group. Air assisted lamellar keratectomy was used to achieve the desired corneal thickness after resection and produce sufficient corneal haze.