Low OD Values Research Articles

Influences of two sizes of nano-Fe3O4 on stereolithography 3D printing properties of gel photoresist for photothermal-responsive hydrogel

Nanocomposite hydrogels enable augmented properties, functions, and responsive behaviors. In the field of stereolithography 3D printing of the photothermal responsive nanocomposite hydrogel, the influence of the size of nano-Fe3O4 on 3D printing properties is significant due to the sedimentation, but the relevant research is rare. In this study, for the fabrication of photothermal responsive hybrid hydrogel, poly(N-isopropylacrylamide-acrylamide)/nano-Fe3O4 [P(NIPAM-AM)/nano-Fe3O4] gel photoresist was prepared and digital light processing (DLP)-based 3D printing as one of the popular stereolithography 3D printing technology was utilized. The influences of two sizes of Fe3O4 nanoparticles (10 and 50 nm) denoted as nano-Fe3O4(10) and nano-Fe3O4(50) on DLP 3D printing properties of the gel photoresist were investigated in detail. The results reveal that the gel photoresist with nano-Fe3O4(10) obtained long exposure time for the basic prototype, low overcuring degree (Od), and good uniformity of nanoparticles in hybrid hydrogels, while those with nano-Fe3O4(50) had the merits of printing high 3D sample due to the low release fore. Unfortunately, the gel photoresist with a high content of nano-Fe3O4 such as 3.11 wt% failed in 3D printing of a high and uniform gel cylinder. A strategy of preparing P(NIPAM-AM)/nano-Fe3O4 gel photoresist with mixed nano-Fe3O4(10) and (50) for 3D printing was proposed. Using the gel photoresist (nano-Fe3O4 content: 3.11 wt%) with two sizes of nano-Fe3O4 mixed with 50% each and the exposure time of 8 s, a gel cylinder with a height of 1 cm was successfully printed with uniform nano-Fe3O4 distribution and low Od values (≤ 1.17%). Further, a biomimetic hydrogel octopus was 3D printed by using the gel photoresist with mixed nano-Fe3O4 and thereafter a near-infrared-light-driven waving motion of octopus tentacle was achieved successfully.

Determination of foot-and-mouth disease serotypes from naturally infected cattle by solid phase competitive ELISA (SPCE) techniques

Objective: Foot and mouth disease (FMD) is a highly infectious and economically important disease affecting cloven-hoofed domestic and wild animals. Early diagnosis and serotyping of the agent are very important to effectively design and implement the control approach. This study was conducted on serum samples collected from Amhara, Tigray, Oromia and Addis Ababa between October 2018 to February 2020. The animals were kept under a semi-intensive to an extensive system of rearing. Serum samples with low OD values (positive) using competition NSP-ELISA were subjected to serotyping ELISA. Results: In the present study, three serotypes were identified from 186 NSP ELISA positive sera of which 156 serotype O, 40 serotypes A and 28 serotype SAT2. In this analysis, multiple serotype infection was observed which is why the number of serotypes was beyond the samples analyzed. Among 23 samples from Addis Ababa 10, 3 and 5 were O, A and SAT2 serotypes respectively, while in samples from the Oromia region 12 were O and 3 were SAT2 serotypes. From the Amhara region, 99 samples analyzed were found to be serotype O and SAT2 in 7 of the serum samples. From the Tigray region, 30 samples were seen to have Serotype O infection, whereas 13 of them were SAT2. The proportion of serotypes identified based on the production system practices was also found that semi-intensive production takes the largest share in all three serotypes followed by extensive production. Generally, early determination of the serotype from past infection helps to aware of the epidemiology as well as the infection immunity of the herd/individual animals.

Inhibition of Autism Spectrum Disorder Associated Bacteria and C. difficile by Polyols

Objectives: To determine the effectiveness of erythritol and xylitol in the inhibition of gut bacteria possibly associated with Autism Spectrum Disorder (ASD) and Clostridium difficile Infection (CDI). Methods: Seven bacterial strains associated with ASD, or with CDI and a control probiotic were tested for polyol inhibitory activity: Clostridium histolyticum, Bacteroides vulgatus, Bifidobacterium longham, and two strains each of Clostridium bolteae and difficile. Each strain was grown in brain heart infusion/sucrose media with polyol concentrations varying from 0% to 15% for erythritol and 0% -30 % for xylitol. Growth of Clostridium histolyticum and Bifidobacterium longham was measured after 24 hours while all other strains were evaluated at 48 hours to permit additional growth. Optical density was measured using a spectrophotometer and the plates were read at 620 nm. Results: All strains had results indicating polyol inhibition of growth. Clostridium histolyticum (Chis), Bifidobacterium longham (Blof), and both Clostridium bolteae (Cbol) strains showed reduced growth with increasing polyol concentration with an inflection point of about 4% for both xylitol and erythritol (complete or near complete inhibition relative to control wells). Bacteroides vulgatus (Bvul) grew very lightly in the BHI/sucrose. This strain has visible growth but very low OD values. Inhibition of growth with increasing polyol concentrations was observed but assessing the polyol inhibition break point was difficult with this strain. Conclusions: Xylitol and erythritol at sufficient concentrations were able to inhibit the growth of bacterial strains that have been associated with the development of Autism Spectrum Disorder in recently published studies.

Seroprevalence of infectious bursal disease virus antibodies in some species of poultry in Maiduguri, Nigeria

This study was aimed at determining the antibodies of IBDV in some poultry species in Maiduguri, Nigeria. A total of 944 serum samples were collected from village chickens, broilers, layers, ducks, turkeys and geese in Maiduguri and tested for IBDV antibodies using inzyme linked Immunosorbent assay (ELISA) and a seroprevalence of 46.6% was recorded. The species distribution showed that 33.4% of local chickens (134/401), 67.3% of layers (35/52), 50.8% of broilers (159/313), 60.6% of turkeys (77/127), 65.5% of ducks (19/29) and 72.7% of geese (16/22) sampled were positive for IBDV antibodies. Males showed a seroprevalence of 70% while females recorded 30%. IBDV seropositive sera showed that samples from broilers reacted with 31.5% middle OD values and turkeys with 9.4% middle OD values. Samples from other species reacted with lower OD values. Samples from other species reacted with lower OD values. Presence of IBDV antibodies in species other than chickens suggested that different bird species might have IBDV and could serve as reservoirs for IBDV transmission. Because of this threat to poultry industry, there is need for continuous surveillance of IBDV in all poultry species so as to institute effective preventive measures against the disease. Keywords: ELISA, Infectious bursal disease virus, IgG, Poultry species, Serum samples

Allergens and intestinal damage induced by soybean antigen proteins in weaned piglets

This study was conducted to investigate the effects of soybean antigen proteins on serum cytokine levels and claudin-1 distribution in the intestine of weaned piglets. Seventy piglets (24 d of age) were randomly divided into seven groups. Piglets in group A were fed a basal diet, in groups B, C and D were fed the basal diet supplemented with β-conglycinin; and in groups E, F, G were fed the basal diet supplemented with glycinin. Blood samples were collected and analysed for IFN-γ, IL-2, IL-4 and IL-6 levels on day 24, 26, 28 and 30. At the end of the trial, five piglets per group were sacrificed and the small intestine was collected to evaluate intestinal claudin-1 distribution and OD of the relative staining positivity. β-Conglycinin and glycinin decreased the growth performance in piglets by decreasing ADFI, ADG and increasing F/G. Serum levels of IL-2, IL-4 and IL-6 in β-conglycinin and glycinin groups ranged from 126.067 to 144.067 ng • L−1, 31.798 to 44.360 ng • L−1 and 36.360 to 40.482 ng • L−1 on day 24, 26 and 30. However, serum IFN-γ levels were negatively correlated with soybean antigen proteins supplementation levels ranged from 6.956 to 15.361 ng • L−1. The treatment groups had lower OD values of claudin-1 than those of the control group. The β-conglycinin groups had lower distribution and OD values than the glycinin groups at similar antigen protein supplementation levels. These results suggest that β-conglycinin and glycinin damage the intestinal mucosal immune barrier in weaned piglets.

Serological Survey of Encephalitozoon cuniculi Infection in Japanese Dogs

Antibodies to Encephalitozoon cuniculi were examined by enzyme-linked immunosorbent assay using E. cuniculi PTP2 recombinant protein and by Western blot analysis on a total of 472 dog serum samples that had been collected in Japan. Of these samples, 21.8% (103/472) had antibodies against E. cuniculi. Each of 5 serum samples that showed high (>1.0) or low (<0.1) OD value was selected randomly and further examined by Western blot using E. cuniculi-native antigens. All samples with high OD values reacted with specific E. cuniculi proteins, including an antigen of approximately 35 kDa corresponding with PTP2; sera with low OD values did not recognize this E. cuniculi band. This study is the first to demonstrate the prevalence of E. cuniculi infection in dogs in Japan.

B-CELL EPITOPE SPECIFICITY OF CARBOXY TERMINUS OF MYCOBACTERIUM PARATUBERCULOSIS ModD

Epitope mapping of ModD of Mycobacterium paratuberculosis was performed using overlapping peptides. In total, 80 overlapping peptides, covering the entire mature ModD, were commercially synthesized. Each peptide spanned 14 amino acids with an offset of 4 amino acids, i.e., with an overlap of 10 amino acids. Synthetic peptide antigenicity was evaluated by enzyme-linked immunosorbent assay (ELISA) using rabbit antisera to culture filtrate (CF) of M. avium or M. paratuberculosis or recombinant ModD (rModD). The peptides o f ModD reacting most strongly (ELISA OD > 1.0) were clustered near the N- and C-terminal ends. The peptides around the C-terminal end only showed the greatest specificity for M. paratuberculosis, yielding high ELISA OD values with rabbit anti-M. paratuberculosis CF serum and low ELISA OD values with rabbit anti-M. avium CF serum. Sera from naturally M. paratuberculosis-infected cattle, however, bound poorly to the short, 14-amino-acid peptides. Thus, two longer peptides covering amino acids 100 to 125 and 328 to 353 were synthesized based on their broad reactivity to rabbit serum against M. paratuberculosis CF. The peptide covering amino acids 328 to 353 showed the highest level of specific bovine antibody binding.

QUANTIFYING METHIONINE WITH A GREEN FLUORESCENT ESCHERICHIA COLI METHIONINE AUXOTROPH

ABSTRACT Methionine is one of the essential and primary limiting amino acids in animal nutrition. In this study, an Escherichia coli methionine auxotroph bacterial strain that exhibited a linear growth response to methionine concentrations was transformed with a plasmid containing genes encoding for a green fluorescent protein, in order to develop a fluorescent bioassay technique for methionine quantitation. Transformants were grown on arabinose‐supplemental media and kept at 27C. The strain was also tested in supplemented media with increasing methionine concentrations, and growth response (measured as optical density [OD]) was compared with fluorescence. The transformed E. coli methionine auxotroph exhibited low OD values, but the OD and fluorescent standard curves used for estimating methionine concentrations were linear with increasing increments of methionine concentration (OD, R2 = 0.97 and 0.89; fluorescent, R2 = 0.90 and 0.89) as were the corresponding fluorescent responses (OD versus fluorescent, R2 = 0.85 and 0.91). The transformed fluorescent strain also responded to enzymatic digests of selected animal feed proteins, yielding differences in available methionine among the different feed protein sources. Using the fluorescence‐based bacterial growth assay to quantify methionine in microtiter plates has potential for assessment of methionine levels in animal feed samples.

Evaluation of clinical and serological data from Taenia solium cysticercosis patients in eastern Inner Mongolia Autonomous Region, China

Neurocysticercosis (NCC) is one of the major causes of neurological disease in China. ELISA and immunoblotting using glycoproteins purified by preparative isoelectric focusing were used to detect human cysticercosis in Tongliao area, Inner Mongolia, China in 1998. Approximately 89% (39 of 44 inpatients and outpatients with suspected NCC at Tongliao City Hospital) were residents of Inner Mongolia. About 53% were male and 77% were of working age (18-59 years), and 32% were farmers. Immunoblotting and ELISA showed a high correlation. Of the 44 patients, 31 positive by cerebral computed tomography (CT) scan were confirmed serologically to have cysticercosis. In the ELISA, patients with no lesions by CT scan had lower OD values, similar to those of normal serum. These findings confirm that both ELISA and immunoblotting assays are sufficiently sensitive to detect asymptomatic or symptomatic cysticercosis patients.

Effects of Paratuberculosis on Productivity in Danish Dairy Cows

Paratuberculosis is a chronic enteritis in dairy cattle and other ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Clinical outbreak causes economic losses due to reduced milk production and slaughter weight and susceptibility to other diseases, and at herd level involuntary culling and death rate are increased. During the last twenty years it has become more and more obvious, that also subclinical paratuberculosis may have an effect on milk production, fertility, milk quality, susceptibility to mastitis, slaughter weight and culling rate. However previous studies of these effects on productivity offer conflicting results, which may be due to herd specific circumstances. In this study antibodies to MAP in milk samples from 7994 cows in 108 Danish herds were tested with enzyme-linked immunosorbent assay (ELISA). Readings were recorded on a continuous scale as the optical density (OD). These OD values were standardised according to parity and stage of lactation as previous studies on the same material show significant increase in ELISA response with increasing parity and in the first and last weeks of the lactation of infected cows. In order to use the diagnostic information in recordings on a continuous scale, subdivision into a positive and negative group by choosing a cut-off value is avoided. Response variables expressing productivity are: milk yield, milk quality (fat, protein and somatic cell count), days open, slaughter quality and weight. At herd level effects on death and culling rate will be analysed. Besides the primary explanatory variable: adjusted ELISA response to MAP, covariables such as age at first calving, parity, calving season, housing system and herd size are included in the analysis. Effects on productivity will be analysed with multi-level regression analyses. A preliminary analysis comparing the lowest10% with the highest 10%of the corrected OD-values indicate that average daily milk yield during the first 24 weeks of lactation, protein content of the milk, slaughter weight and quality are reduced in cows with high OD-values (probably infected cows) compared to cows with low OD-values (probably non-infected cows). More detailed analyses at cow and herd level will be presented at the 11th ICPD in August 2001.

Detection of antibodies to Borna disease virus (BDV) in Turkish horse sera using recombinant p40. Brief report.

The nucleoprotein of Borna disease virus (BDV-p40) was produced in a Baculovirus expression system using sf9 cells. The purity and specificity of the recombinant p40 was confirmed by SDS-PAGE and immunoblotting. The recombinant p40 was used in an ELISA to screen horse sera in Turkey. For this, 323 horses from selected cities in the Marmara region of Turkey were examined clinically and serum was collected from each. All horses were clinically healthy except for a few with wounds on the skin. Antibodies to BDV were detected in the sera of 82 (25%) of 323 horse sera. Six sera were selected that had low, medium or high OD values by ELISA and were analysed by Western blotting. All reacted specifically with p40 at a dilution of 1 in 1000. This is the first report of the detection of Borna disease in Turkey and needs further molecular biological investigations to compare the Turkish strains with those strains detected in Europe.

Detection of enteroviruses by polymerase chain reaction in urine samples of patients with aseptic meningitis.

Detection of enteroviruses by polymerase chain reaction in urine samples of patients with aseptic meningitis.