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Controlling the growth of food-borne pathogens in foodstuffs is important to enhance food safety and promote higher food safety standards. A number of naturally occurring compounds (e.g., bacteriocins and plant-derived compounds) have been widely reported to be safe and effective antimicrobial agents against spoilage and food-borne pathogenic bacteria. The aim of the present work was to evaluate the antibacterial potential of a semi-purified preparation (SPP) containing bacteriocin from Bacillus velezensis BUU004, a mixture of lemongrass (Cymbopogon citratus (DC) Stapf.), chili spur pepper (Capsicum frutescens L.) extracts, and their combination to control the growth of Escherichia coli and Salmonella Typhimurium in dried, crushed, and seasoned squid during 28 d of storage. The mixed herb extracts (160 mg/mL) showed stronger inhibitory activity against E. coli and S. Typhimurium than the SPP (800 AU/mL) from B. velezensis BUU004. Interestingly, the combination of SPP from B. velezensis BUU004 and the mixed herb extracts substantially decreased the numbers of both pathogens in dried seasoned squid during storage as compared to that observed with the individual additives. The bactericidal activity of the SPP from B. velezensis BUU004 in combination with the mixed herb extracts against the food-borne pathogens involved cell lysis as ruptured cell walls were observed by a scanning electron microscopy. Therefore, the SPP from B. velezensis BUU004 combined with the mixed herb extracts offers tremendous advantages as a novel, safe, natural, and effective way to improve the biosafety of dried seafood products. [ABSTRACT FROM AUTHOR]

Several microorganisms, including Bacillus and yeasts species, are widely used as aquaculture probiotics. In the present study, a mixed Bacillus sp. contained five species of B. thuringiensis BUU 001, B. megaterium BUU 002, B. polymyxa BUU 003, B. licheniformis BUU 004, and B. subtilis BUU 005, and a mixed yeast probiotics contained Debaryomyces hansenii BUU 01 and Rhodotorula sp. BUU 02. The effects of mixed microbial probiotics as a dietary supplement on growth, survival, and microbiological changes of juvenile whiteleg shrimp (Litopenaeus vannamei) were investigated. Shrimp (~5.7–5.8 g) were fed a commercial diet alone (control) or with one of three probiotic supplements—freeze-dried mixture of Bacillus (FB), freeze-dried mixture of Bacillus and yeast (FBY), and freeze-dried mixture of yeast (FY)—for 90 days in simulated earthen ponds. Growth of FB-fed shrimp was significantly higher (P < 0.05) than those fed with FBY, FY, and control diets. However, survival was not significantly different (P > 0.05) among the three treated groups but was significantly higher (P < 0.05) than that of the control. Numbers of culturable heterotrophic bacteria in intestine were not significantly different (P > 0.05) among the four groups. Bacillus numbers in FB- and FBY-fed shrimp increased significantly (P < 0.05) in intestine. Yeast numbers in intestine of FBY- and FY-treated shrimp were significantly higher (P < 0.05) than those of FB-treated and control shrimp and increased significantly (P < 0.05) during the rearing period, while no yeast was observed in FB-treated and control shrimp. Numbers of Vibrio in intestine were significantly lower (P < 0.05) in the three treated groups than the control. Administration of mixed Bacillus, mixed yeasts, or Bacillus mixture in combination with mixed yeasts resulted in improved (P < 0.05) growth and survival and reduced Vibrio numbers along with an increase in beneficial probiotic abundance and a decrease in the number of potential pathogenic bacteria (V. parahaemolyticus and V. cholerae) in digestive tract of juvenile L. vannamei. [ABSTRACT FROM AUTHOR]

Development of a novel biopreservative harmless to human health has gained increasing attention to control spoilage and pathogenic bacteria in food products. The aims of the present work were to characterise partially purified substance from Bacillus velezensis BUU004 (PBV), evaluate its cytotoxicity, and assess the presence of encoding genes associated with enterotoxin production in B. velezensis BUU004. The highest antibacterial activity was achieved at 18 h post-incubation in stationary growth phase. The PBV containing bacteriocin displayed proteinaceous nature because its activity was partially inactivated by chymotrypsin and papain, and fully degraded by pepsin, proteinase K and trypsin. Bacteriocin in PBV was thermoresistant up to 96°C, and pH stable ranging from 3.0 - 9.0. It also showed a broad spectrum of antibacterial activity against B. cereus, B. coagulans, Listeria monocytogenes, Micrococcus luteus, Staphylococcus aureus, Escherichia coli, E. coli O157:H7, and Salmonella Typhimurium. The molecular weight of the bacteriocin was approximately 5.75 kDa, and the amino acid sequence revealed 43% similarity with existing antimicrobial peptides as determined by an LC-MS/MS analysis. Furthermore, B. velezensis BUU004 produced the bacteriocin that has a low IC50 of 927.4 µg/mL to HK-2 cells along with absence of enterotoxin genes: cytotoxin K (cytK), hemolysin (hlyII), hemolytic enterotoxin HBL (hblABCD), nonhemolytic enterotoxin NHE (nheABC) and cereulide (cesABCD), indicating its basic biosafety characteristic. Our results suggest that a bacteriocin produced by B. velezensis BUU004 has promising potential as a safe biopreservative in the food industry. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the efficacy of dry shipper for the cryostorage of silver barb (Barbodes gonionotus) sperm, the subsequent risk of bacterial cross-contamination, and the effects of Aeromonas hydrophila on post-thaw sperm. Semen was diluted with calcium-free Hank's balanced salt solution containing 10% ME 2 SO, frozen at -8 °C/min and stored for 14 d in a dry shipper. A significant decline (P < 0.05) in the post-thaw sperm motility and viability of samples kept in the dry shipper for 14 d showed a reverse correlation (P < 0.05) with a slight increase in temperature within the dry shipper. The levels of contaminated bacteria in the compartments of the dry shipper were significantly (P < 0.05) lower than those detected in the liquid nitrogen tank. Bacteria from the atmosphere could recontaminate the chambers of the dry shipper and liquid nitrogen tank after 14 d. Bacillus was the most common bacteria isolated from the dry shipper, liquid nitrogen tank, circulating air, bench surface and outer surface of straws. There was no cross-contamination of A. hydrophila from contaminated straws to pathogen-free straws kept in either cryogenic tank. Post-thaw sperm motility and sperm viability significantly (P < 0.05) declined during cryostorage in the dry shipper and liquid nitrogen tank due to the introduction of A. hydrophila and the interaction effect of A. hydrophila and freezing. This study reports, for the first time, the efficacy of a dry shipper for the cryostorage of fish sperm for at least 14 d without a risk of bacterial cross-contamination., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purposive use of cryopreserved sperm contaminated with pathogenic agents has increased the risk of spreading of fish diseases. The objective of this study was to investigate the effects of A. hydrophila subsp. hydrophila and P. fluorescens inoculations into cryostored milt on fertilization capacity and transmission potential to embryos of silver barb (Barbodes gonionotus) with or without 0.25% penicillin-streptomycin (PS) administration. The experiment comprised six treatments: addition of milt into T1) extender only, T2) extender with 0.25% PS, T3) extender with A. hydrophila subsp. hydrophila (BG19), T4) extender with A. hydrophila subsp. hydrophila (BG19) and 0.25% PS, T5) extender with P. fluorescens (BG20) and T6) extender with P. fluorescens (BG20) and 0.25% PS. Milt were loaded into 0.25-mL straws and cryostored in the controlled-rate programmable freezer. After a cryostorage for 28 d, post-thawed sperm were evaluated for the fertilization capacity and risk of pathogen transmission to embryos. Inoculation of A. hydrophila subsp. hydrophila and P. fluorescens into extended milt (T3 and T5) caused a reduction (P < 0.05) in fertilization capacity of cryopreserved sperm. Cryopreserved sperm inoculated with the two pathogenic bacteria and 0.25% PS (T4 and T6) did not fertilize the eggs. The two pathogenic bacteria could be transmitted into embryos after artificial insemination of eggs with bacterial-inoculated cryopreserved sperm, suggesting that the risks of disease transmission via cryopreserved fish sperm would exist. This is the first study reporting pathogenic bacterial transmission on in vitro fish embryos through artificial insemination of cryopreserved sperm., (Copyright © 2017. Published by Elsevier Inc.)

This objective of the study was to evaluate the effects of A. hydrophila subsp. hydrophila and P. fluorescens on sperm motility, sperm viability and sperm morphometry of cryopreserved silver barb (Barbodes gonionotus) semen and survival of tested bacteria after cryostorage. Semen was diluted in a calcium-free Hank's balanced salt solution (Ca-F HBSS) supplemented with or without 0.25% penicillin-streptomycin (PS) after which A. hydrophila subsp. hydrophila or P. fluorescens was immediately added into extended semen prior to freezing. Extended semen and cryostored semen kept for 20 min, 24 h, 7 d, 14 d and 28 d were assessed for sperm motility, sperm viability, sperm morphometry, survival of challenged bacteria and the relationship between bacteria and sperm. Bacterial-exposed semen with or without 0.25% PS supplementation showed a significant reduction (P < 0.05) in sperm motility and viability during a cryostorage of 28 d, compared to semen without bacterial supplementation (control groups). Addition of A. hydrophila subsp. hydrophila and P. fluorescens resulted in a significant (P < 0.05) alteration of sperm morphometry of cryopreserved semen, especially flagellum width. The two pathogens were detected at a level of 10(5) CFU ml(-1) in cryostored semen with or without antibiotic supplementation. There were significant correlations among bacterial number, percentage of sperm motility and viability and flagellum width. In conclusion, the presence of A. hydrophila subsp. hydrophila and P. fluorescens had a deleterious effect on cryopreserved silver barb sperm based on a reduction in sperm motility and viability and alteration of sperm morphometry, especially flagellum width., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Disease prevention is a key aspect in developing cryopreservation procedures for fish sperm and in improving the reproductive biotechnology for commercially important aquatic species. The purpose of this study was to evaluate the effects of an antibiotic supplementation (0.25% penicillin-streptomycin, PS and 0.25% penicillin-gentamicin, PG) on sperm motility and viability, bacterial profile and fertilization capacity of cryopreserved silver barb (Barbodes gonionotus) semen. The experimental protocol involved three treatments: addition of PS alone; addition of PG alone; and no addition of antibiotics (Control). Semen samples were frozen and cryostored for 12-mo. Administration of 0.25% PS significantly (P<0.05) improved sperm motility and viability and reduced (P<0.05) total heterotrophic bacteria, Gram negative bacteria and pseudomonads bacteria in cryopreserved semen. Post-thawed semen treated with 0.25% PS did not contain contaminating bacteria including Bacillus subtilis subsp. inaquosorum, Bacillus safensis, Aeromonas punctata subsp. caviae, Serratia plymuthica, Pseudomonas azotoformans and Pseudomonas sp. Post-thawed semen supplemented with 0.25% PG showed degenerative changes in motility and viability of sperm. Eggs fertilized with 0.25% PS or antibiotic-free cryopreserved semen had similar fertilization rates, lower (P<0.05) than those of fresh semen. Incorporation of 0.25% PS was suitable for cryopreservation of silver barb semen based on the presence of good quality of post-thawed sperm and elimination of bacterial contaminants: B. subtilis subsp. inaquosorum, B. safensis, A. punctata subsp. caviae, Ser. plymuthica, P. azotoformans and Pseudomonas sp. This is the first study to investigate the antibiotic effect on the number of bacteria and their profile in cryopreserved semen of fish., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Biosafety issue associated with the risk of pathogenic contamination of cryopreserved semen is a common concern because of associated declines in sperm quality, storage period and disease transmission. This study was conducted to evaluate the effects of methods of semen collection on sperm quality and bacterial composition of post-thawed semen of silver barb (Barbodes gonionotus). Semen collection methods consisted of four treatments: (1) hand-stripping of abdomen without rinsing of urogenital area with water, (2) hand-stripping of abdomen after rinsing of urogenital area with water, (3) catheterization without rinsing of urogenital area with water and (4) catheterization after rinsing of urogenital area with water. Semen diluted with calcium-free Hank's balanced salt solution containing 10% dimethylsulfoxide (DMSO) was frozen at a freezing rate of -8°Cmin(-1) before plunging in liquid nitrogen. Post-thawed semen collected by catheterization after rinsing urogenital area had the lowest bacterial number, about 2-log reduction of total heterotrophic, Gram negative and pseudomonad bacteria, compared with the other three collection treatments. However, percentages of motile and viable sperm were not significantly (P>0.05) different among treatments. This method eliminated Flavobacterium aquatile, Bacillus megaterium, Kocuria varians, Staphylococcus haemolyticus and Aeromonas media in cryopreserved semen. This is the first report demonstrating the effects of semen collection methods on bacteriological quality of frozen-thawed fish semen., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Epidemics of epizootics and occurrence of multiresistant antibiotics of pathogenic bacteria in aquaculture have put forward a development of effective probiotics for the sustainable culture. This study examined the effectiveness of forms of mixed Bacillus probiotics (probiotic A and probiotic B) and mode of probiotic administration on growth, bacterial numbers and water quality during rearing of white shrimp (Litopenaeus vannamei) in two separated experiments: (1) larval stages and (2) postlarval (PL) stages. Forms of Bacillus probiotics and modes of probiotic administration did not affect growth and survival of larval to PL shrimp. The compositions of Bacillus species in probiotic A and probiotic B did not affect growth and survival of larvae. However, postlarvae treated with probiotic B exhibited higher (P<0.05) growth than probiotic A and controls, indicating Bacillus probiotic composition affects the growth of PL shrimp. Total heterotrophic bacteria and Bacillus numbers in larval and PL shrimp or culture water of the treated groups were higher (P<0.05) than in controls. Levels of pH, ammonia and nitrite of the treated shrimp were significantly decreased, compared to the controls. Microencapsulated Bacillus probiotic was effective for rearing of PL L. vannamei. This investigation showed that administration of mixed Bacillus probiotics significantly improved growth and survival of PL shrimp, increased beneficial bacteria in shrimp and culture water and enhanced water quality for the levels of pH, ammonia and nitrite of culture water., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The objective of this study was to determine the effects of various extenders, cryoprotectants and cryopreservation methods on post-thaw sperm motility and duration of sperm motility in common carp (Cyprinus carpio). We focused on freezing of common carp sperm utilizing a practical and inexpensive protocol for aquaculture. Sperm were diluted 1:1 in one of six extenders (common carp sperm extenders; CCSE 1-CCSE 6) containing three types of cryoprotectants (dimethyl sulfoxide; DMSO, methanol; MET and propylene glycol; PG) at a final concentration of 10%, and frozen at a rate of 10°C/min from an initial temperature 25 to -40°C before storage in liquid nitrogen. The results demonstrated that sperm diluted with CCSE 2 and DMSO had the best post-thaw motility (94.5 ± 3.3%), similar to that of the control (98.6 ± 0.7%; P>0.05). Duration of sperm motility from a treatment with CCSE 2 and DMSO (97 ± 20.8s) was not significantly different (P>0.05) from that of the control (73.3 ± 12.9s). A second experiment studied the effects of various cryopreservation methods on post-thaw sperm motility and duration of sperm motility, based on using CCSE 2 and DMSO in all treatments. Sperm were frozen using different cryopreservation methods: direct immersion into liquid nitrogen, controlled-rate programmable freezer, or exposure to liquid nitrogen vapor at different heights and time. Sperm frozen at a height of 2 cm above liquid nirogen surface for 10 min gave the highest post-thaw sperm motility (91.7 ± 7.8%) and longest duration of post-thaw sperm motility (105.7 ± 23.1s). Sperm frozen 2 cm above liquid nitrogen surface for 10 min produced the highest fertilization and hatching rate of about 73.6 ± 6.5% and 62.8 ± 5.9%, respectively, not significant different (P>0.05) from those of fresh sperm (75.6 ± 7.5% and 66.5 ± 4.8%, respectively). This study reports superior performance of the combination of CCSE 2 and DMSO for freezing common carp sperm that resulted in high fertilization capacity., (Copyright © 2010 Elsevier B.V. All rights reserved.)

This research was the first long-term attempt to concurrently measure and identify major sources of both PM(10) and PM(2.5) in Bangkok Metropolitan Region (BMR). Ambient PM(10) and PM(2.5) were evaluated at four monitoring stations and analyzed for elemental compositions, water-soluble ions, and total carbon during February 2002-January 2003. Fifteen chemical elements, four water-soluble ions, and total carbon were analyzed to assist major source identification by a receptor model approach, known as chemical mass balance. PM(10) and PM(2.5) were significantly different (p<0.05) at all sites and 24 h averages were high at traffic location while two separated residential sites were similar. Seasonal difference of PM(10) and PM(2.5) concentrations was distinct between dry and wet seasons. Major source of PM(10) at the traffic site indicated that automobile emissions and biomass burning-related sources contributed approximately 33% each. Automobiles contributed approximately 39 and 22% of PM(10) mass at two residential sites while biomass burning contributed about 36 and 28%. PM(10) from re-suspended soil and cooking sources accounted for 10 to 15% at a residential site. Major sources of PM(2.5) at traffic site were automobile and biomass burning, contributing approximately 32 and 26%, respectively. Biomass burning was the major source of PM(2.5) mass concentrations at residential sites. Meat cooking also accounted for 31% of PM(2.5) mass at a low impact site. Automobile, biomass burning, and road dust were less significant, contributed 10, 6, and 5%, respectively. Major sources identification at some location had difficulty to achieve performance criteria due to limited source profiles. Improved in characterize other sources profiles will help local authority to better air quality.

Thioredoxin-related protein of 14 kDa, TRP14, has previously been identified only in humans. Here we report the identification and expression of an amphioxus TRP14 gene, named AmphiTRP14, the first such data in a non-mammalian organism. AmphiTRP14 consists of a 372-bp open reading frame coding for a 123-amino-acid protein with a calculated molecular weight of 14 kDa. It shares 56% identity with human TRP14 and possesses a highly conserved motif CPDC. Sequence comparison suggests the evolutionary appearance of the four-exon-three-intron organization of TRP14 genes after the split of protostome/deuterostome, which is highly conserved since then. AmphiTRP14 has been successfully expressed in Escherichia coli and purified. The recombinant protein exhibited features characteristic of human TRP14, including a reductase activity towards insulin. Both in situ hybridization histochemistry and immunohistochemistry revealed that AmphiTRP14 was expressed in a tissue-specific manner, with the most abundant expression in the hepatic caecum, ovary and hind-gut. This suggests that AmphiTRP14 plays a fundamental but tissue-specific role, or alternatively reflects differences in the tissue susceptibility to oxidative damage.

Three hundred and four strains of beta-hemolytic streptococci were isolated from different patients at Siriraj Hospital during 1989-1990. Among these strains, 24.01% were group A, 23.03% were group B, 2.96% were group C, 29.61% were group D, 0.66% were group F, 6.25% were group G and 13.48% could not be grouped by using the Lancefield reference method. The distribution of each serogroup according to the types of clinical specimens was also studied. From pus, group A Streptococcus (44.8%) was the most frequent isolate. From vagina/cervix/urethra specimens, group B Streptococcus (47.95%) was the most frequent isolate. From urine, group D Streptococcus (82.5%) was the most frequent isolate. From blood, group B Streptococcus (43.33%) was the most frequent isolate. From throat/sputum specimens, only group A Streptococcus was isolated. There were some differences in susceptibility to 19 antimicrobial agents among various groups of streptococci. Resistance to penicillin was not found in groups A, B, C, F and G streptococci except for group D (91.1% resistance for enterococci and 33.3% resistance for non-enterococci) and nongroupable streptococci (12.2% resistance).