• Journal of Dairy Science and Biotechnology
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• v.41 no.3
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• pp.126-137
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• 2023

In this study, we isolated lactic acid bacteria from Allium wakegi and examined the usability of culture supernatants obtained from these lactic acid bacteria. The antibacterial activity of the culture supernatant obtained from the isolated lactic acid bacteria against the pathogens Escherichia and Salmonella spp. was measured. The obtained lactic acid bacteria culture medium showed significant antibacterial activity against pathogenic bacteria in a dose-dependent manner. The effects of pH and heat denaturation on the observed anti-pathogenic bacterial activity was also investigated. Adjusting the culture supernatant to pH 7 resulted in loss of all antibacterial activity against pathogenic bacteria, suggesting that the antibacterial activity of the obtained culture supernatant against pathogenic bacteria is influenced by organic acids. Assessment of the heat stability of the anti-pathogenic bacterial activity revealed that heat treatment did not diminish activity. The obtained lactic acid bacteria culture medium is thus stable against heat.

• Journal of Dairy Science and Biotechnology
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• v.41 no.4
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• pp.191-202
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• 2023

In this study, lactic acid bacteria (LAB) was isolated from blueberries. The isolated LAB were rod-shaped and gram-positive, as shown using gram staining. In addition, the identified bacteria showed high homology to Lactiplantibacillus argentoratensis. The culture supernatant was isolated from L. argentoratensis and its antibacterial activity against the pathogenic bacteria Salmonella and Escherichia was analyzed. Culture supernatants of L. argentoratensis significantly inhibited the growth of Salmonella. Enteritidis NCCP 16947, Salmonella Typhimurium NCCP 16960, and Salmonella. Thompson NCCP 11704. Interestingly, the higher the concentration of the culture supernatant, the more significant was the antibacterial activity. Additionally, the culture supernatant of L. argentoratensis showed significant antibacterial activity against Escherichia strains. To determine whether the antibacterial substance is stable to heat and pH, the LAB culture supernatant was heat-treated under 65℃ for 30 min, 75℃ for 15 min, 85℃ for 10 min, and 100℃ for 5 min. Measurement of antibacterial activity against pathogenic strains by adding 5% of heat-treated culture medium showed the same antibacterial activity as before heat treatment. However, in a test where the pH of the culture supernatant was adjusted to 7.0 from 3.73, no antibacterial activity was observed.

• Journal of Embryo Transfer
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• v.25 no.3
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• pp.171-177
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• 2010

Plasminogen activators (PAs) are serine proteases that convert plasminogen to plasmin. The PA/plasmin system has been associated with a number of physiological processes such as fibrinolysis, ovulation and fertilization. Although correlations have been reported between reactive oxygen species (ROS) and oocyte maturation, the relationship between PA activity and ROS is unknown. The present study was undertaken to determine the effects of cumulus cells on PA activity in matured porcine oocytes under xanthine (X)-xanthine oxidase (XO) system. When oocytes were matured under the X-XO system, the proportion of oocytes remaining GV stage was higher (p<0.05) in oocytes without cumulus cells. The incidence of degenerated oocytes was higher (p<0.05) in the X+XO ($11.1{\pm}6.1$ and $21.6{\pm}3.4%$) than in the control group ($2.9{\pm}1.8$ and $4.0{\pm}1.6%$). The proportion of TUNEL-positive oocytes and activity of caspase-3 were higher (p<0.05) in cumulus-free oocytes and oocytes exposed to ROS. Tissue-type plasminogen activator-plasminogen activator inhibitor (tPA-PAI) and tissue-type plasminogen activator (tPA) activity were detected in oocytes that were separated from cumulus-oocytes complexs (COCs) at 44 h of maturation culture, and only tPA was produced in oocytes that were denuded before the onset of maturation culture. On the other hand, the activities of PA were increased (p<0.05) when oocytes were cultured under the X-XO system. The higher activity of tPA was observed in denuded oocytes (DOs) underwent apoptotic changes by oxidative stress. In COCs, however, tPA-PAI as well as tPA activity was detected and apoptotic changes such as DNA cleavage or caspase-3 activation were not observed. These results suggest that tP A may be relevant to apoptotic cell death in porcine oocytes by oxidative stress.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.281-284
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• 1991

Combination effects of sulfamethoxazole (SMX) and trimethoprim (TMP) against nine gram positive bacterial strains and 43 gram negative bacterial strains which included 40 strains of animal intestinal bacteria were studied in vitro. Minimum inhibitory concentrations (MICs) of SMX and TMP alone and 20:1 (SMX : TMP) mixture (ST) were investigated by the method recommended by Ad Hoc Committee of the Japan Society of Chemotherapy for the Evaluation of Sensitivity Testing Methods for Sulfamethoxazole and Trimethoprim. MICs of ST were more potentiated than those of SMX alone in 8 of 9 gram positive strains and 40 of 43 gram negative strains. Especially, 38 strains of 40 intestinal bacteria showed significant susceptibility to ST as compared to SMX. These results suggest a strong synergistic activity of ST mixture against animal intestinal bacteria, The activity was considered to be comparable to those of other current antibiotics.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1794-1802
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• 2001

Biotechnology will play critical role in improving animal productivity. Animal growth rate and muscle deposition potential can be greatly improved by the application of biotechnology and biotechnological products. Administration of recombinant somatotropin (ST) or other compounds such as IGF-1 and growth hormone-releasing peptides (GHRPs) can enhance growth rate and carcass lean percentage. Gene transfer offers a powerful approach to manipulate endocrine system and metabolic pathways toward faster growth and better feed efficiency. Biotechnology is also extensively used for improving metabolism and activity of gut microorganisms for better nutrient digestibility. Knockout of growth-inhibiting genes such as myostatin results in considerable acceleration of body weight and muscle growth. Animal growth can also be improved by the use of gene therapy. Immunomodulation is another approach for efficient growth through controlling the activity of endogenous anabolic hormones. All the above aspects will be discussed in this review.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.811-815
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• 2001

The study evaluated different synthetic and semisynthetic media for maximal recovery of rumen bacteria and expression of their antibacterial activity. Rumen Glucose Cellobiose Agar (RGCA) medium was found to be the best for recovery of rumen bacteria. However, L-10 medium was the best for expression of antibacterial activity of ruminal isolates followed by Easy, M-10, RGCA and M-98-5 medium. The present study recommends the use of L-10 medium as the medium of choice for screening of antibacterial activity of ruminal isolates. Comparative evaluation of bacterial counts on different dietary regimes indicated significant difference between different growth media on a specific diet and between diets on specific growth media within a species. However, there is no overall significant difference between total bacterial counts obtained from rumen liquor of cattle and buffalo with respect to either the feeding regime or growth media. Feeding straw based diet to the animal is the best for high recovery of rumen bacteria.

• Parasites, Hosts and Diseases
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• v.59 no.5
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• pp.439-445
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• 2021

Coccidiosis in chickens is an intestinal parasitic disease caused by protozoan parasites named Eimeria spp. In some Eimeria infections, intestinal lymphocytes are known to highly express chicken NK-lysin (cNK-lysin), an antimicrobial peptide with anticoccidial activity. Therefore, this study aims to investigate the expression of cNK-lysin in E. necatrix-infected chickens and its role in E. necatrix infection. The expression of cNK-lysin transcript was significantly increased in E. necatrix sporozoites-treated lymphocytes. In E. necatrix infection, cNK-lysin transcript was induced in intestinal lymphocytes but not in the spleen. The recombinant cNK-lysin exhibited anticoccidial activity against E. necatrix sporozoites as well as immunomodulatory activity on macrophages by inducing proinflammatory cytokines. These results indicated that E. necatrix infection induces high local expression of cNK-lysin and the secreted cNK-lysin helps protect coccidiosis.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1054-1058
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• 2000

The objective of this study was to determine the effect of draught stress on certain haemograms and ovarian activity and the influence of dietary supplementation on the negative effects of draught in cows. Blood parameters and ovarian activity were assessed in supplemented non-working (SNW), supplemented working (SW) and non-supplemented non-working (NSNW) cows. Body weights and body condition scores were recorded fortnightly. Blood samples were collected through jugular venipuncture in December, February and April to determine the contents of haematocrit, erythrocyte, haemoglobin and white blood cells. Ovarian palpations were carried out in October, January and April. The SW cows maintained body weights (p>0.05) during the monitoring period whereas both SNW and NSNW cows gained (p<0.05) body weights. Body condition scores were similar between SW and NSNW cows. Cows in the NSNW group had lower (p<0.05) haematocrit concentrations in April than both supplemented groups. In December, erythrocyte concentrations were similar (p>0.05) among all treatment groups. Haemoglobin concentrations were higher (p<0.05) in SW and SNW cows in February and April than in December. The SW cows had higher leucocyte contents (p<0.05) in February than the other groups of cows. All treatment groups showed similar (p>0.05) ovarian activity in January. However, the NSNW group showed a lower proportion (p<0.05) of cows that exhibited normal ovarian activity in April. The results suggest that dietary supplementation of cows increases haematocrit and haemoglobin contents. In addition, supplementary feeding during the period of draught power provision maintains ovarian activity in cows.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.714-718
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• 2003

This study was conducted to determine the effect of DL-methionine (Met) and DL-methionine hydroxy analogue (MHA) supplementation on the growth performance, contents of serum amino acids and activities of digestive protease in broiler chicks from 0 to 3 weeks old . There were three treatments in this study: (1) control (basal diet), (2) 0.24% Met supplementation and (3) 0.368% MHA supplementation. The results showed that Met and MHA supplementation did not significantly (p>0.05) improve feed efficiency and body weight gain for broilers from 0-1, 0-2 and 0-3 weeks of age. The serum levels of homocystine, methionine and taurine were significantly (p<0.05) higher with supplementation of Met or MHA than with control. The pepsin activity of proventriculus was increased with (p<0.05) Met supplementation at 21 days of age and with MHA supplementation at 7 and 14 days of age. The trypsin activity was also increased (p<0.05) with MHA supplementation at 7 days of age. The chymotrypsin activity in pancreas and the dipeptidase activity in small intestinal mucosa and content were not affected (p>0.05) by Met or MHA supplementation.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1426-1432
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• 2018

Staphylococcus aureus causes a broad variety of diseases. The spread of multidrug-resistant S. aureus highlights the need to develop new ways to combat S. aureus infections. Sortase A (SrtA) can anchor proteins containing LPXTG binding motifs to the bacteria surface and plays a key role in S. aureus infections, making it a promising antivirulence target. In the present study, we used a SrtA activity inhibition assay to discover that isovitexin, a Chinese herbal product, can inhibit SrtA activity with an $IC_{50}$ of $28.98{\mu}g/ml$. Using a fibrinogen-binding assay and a biofilm formation assay, we indirectly proved the SrtA inhibitory activity of isovitexin. Additionally, isovitexin treatment decreased the amount of staphylococcal protein A (SpA) on the surface of the cells. These data suggest that isovitexin has the potential to be an anti-infective drug against S. aureus via the inhibition of sortase activity.