Transmission of methicillin-resistant Staphylococcus aureus strains between different kinds of pig farms     

van Duijkeren E  Ikawaty R  Broekhuizen-Stins MJ  Jansen MD  Spalburg EC  de Neeling AJ  Allaart JG  van Nes A  Wagenaar JA  Fluit AC 《Veterinary microbiology》2008,126(4):383-389

The main objective of the present study was to investigate if different kinds of pig farms, like farrowing farms and rearing farms, play a role in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) to Dutch finishing farms. Twelve farrowing farms, 11 finishing farms, 6 farrow-to finish farms, 1 rearing farm and 1 centre for artificial insemination were included. Screening of 310 pigs from these 31 farms showed 35 pigs (11%) to carry MRSA in their nares. On 7 of the 31 (23%) investigated farms colonized pigs were found, including 3 finishing farms, 3 farrowing farms and 1 farrow-to-finish farm. The use of standard antimicrobial medication of the pigs seemed to be a risk factor for MRSA carriage. Screening of the pigs on six farms supplying pigs for the MRSA positive farms revealed that the pigs on all but one farm were MRSA positive. Genotyping revealed that all MRSA strains were non-typeable by PFGE using the SmaI restriction enzyme and had multilocus sequence type (MLST) ST398. Different spa-types were found including t011, t108, t567, t899 and t1939, but the spa-types on epidemiologically related farms were identical indicating that MRSA are transmitted between farms through the purchase of colonized pigs. Two SCCmec types were found among the MRSA: type IV and type V. SCCmec type V was predominant. On two farms MRSA isolates with ST398, the same spa-type but with different SCCmec types (IV and V) were found, suggesting that different SCCmec elements have been inserted into MSSA with the same genotype. All MRSA strains were resistant to tetracycline, but additional resistances to erythromycin, lincomycin, kanamycin and gentamicin were also found. All MRSA isolates were negative for the exfoliative toxin genes (eta and etb), PVL toxin genes (lukF and lukS), toxic shock syndrome gene (tst-1), and the leukotoxin genes (lukE, lukD, lukM, lukF').  相似文献   

In vitro and in vivo bioactivity of recombinant canine hepatocyte growth factor   总被引：1，自引：0，他引：1  

Arends B  Spee B  Hoffmann G  Jansen GE  Slump E  Auriemma E  Ijzer J  Hemrika W  Romijn RA  van der Heijden-Liefkens KH  Sondermeijer PJ  van den Ingh TS  Penning LC  Rothuizen J 《Veterinary journal (London, England : 1997)》2008,178(1):70-77

Hepatocyte growth factor (HGF) is crucial for the development and regeneration of the liver and offers a possible new therapeutic strategy for the treatment of canine liver disease. In this study, the in vitro and in vivo bioactivity of recombinant canine HGF (rcHGF) produced with a baculoviral expression system in insect cells was measured. In vitro rcHGF induced mitogenesis, motogenesis, and phosphorylated the HGF receptor c-MET and its downstream mediators PKB and ERK1/2 in two canine epithelial cell lines. After a partial hepatectomy (phx) in dogs, rcHGF increased phosphorylation of c-MET, PKB and ERK1/2. A moderate increase was seen with the cell cycle protein PCNA in rcHGF treated livers, but no HGF-induced increase in liver weight was seen 7 days after phx. Furthermore, rcHGF treated livers showed lower levels of the key mediator of apoptosis, caspase-3, at 7days after phx. It is concluded that rcHGF is a biologically active protein in vitro and in vivo and the baculoviral expression system supplies sufficient amounts of rcHGF for future clinical studies in dogs.  相似文献   

Tracking the long-term decline and recovery of an isolated population     

RL Westemeier  JD Brawn  SA Simpson  TL Esker  RW Jansen  JW Walk  EL Kershner  JL Bouzat  KN Paige 《Science (New York, N.Y.)》1998,282(5394):1695-1698

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.  相似文献   

Volatile composition of sunflower oil-in-water emulsions during initial lipid oxidation: influence of pH.     

S M van Ruth  J P Roozen  M A Posthumus  F J Jansen 《Journal of agricultural and food chemistry》1999,47(10):4365-4369

The formation of odor active compounds resulting from initial lipid oxidation in sunflower oil-in-water emulsions was examined during storage at 60 degrees C. The emulsions differed in initial pH, that is, pH 3 and 6. The volatile compounds were isolated under mouth conditions and were analyzed by gas chromatography/sniffing port analysis. The lipid oxidation rate was followed by the formation of conjugated hydroperoxide dienes and headspace hexanal. The initial pH affected the lipid oxidation rate in the emulsions: the formation of conjugated diene hydroperoxides and the hexanal concentration in the static headspace were increased at pH 6. Pentanal, hexanal, 3-pentanol, and 1-octen-3-one showed odor activity in the emulsions after 6 days of storage, for both pH 3 and 6. Larger amounts of odor active compounds were released from the pH 6 emulsion with extended storage. It was shown that this increased release at pH 6 was not due to increased volatility because an increase in pH diminished the static headspace concentrations of added compounds in emulsions.  相似文献   

A three‐year field study on the short‐term effects of insecticides used to control cereal aphids on plant‐dwelling aphid predators in winter wheat     

Jean Pierre Jansen 《Pest management science》2000,56(6):533-539

Short‐term effects of six insecticides used to control aphids were assessed in wheat on plant‐dwelling aphid predators. Products were applied to small plots of winter wheat in June or at the beginning of July and the densities of predators were estimated three days after treatment using a beating method. Insecticides were tested in 1994, 1995 and 1997 at a single dose, corresponding to their maximum recommended field rate in Belgium. Fluvalinate and esfenvalerate did not significantly reduce catches of syrphid larvae compared to the control but ladybirds were affected by these compounds. Pirimicarb was the only product tested that had no effect on ladybirds. However, syrphid larvae appeared sensitive to this product. Cyfluthrin, deltamethrin and phosalone reduced catches of both syrphids and ladybirds. Populations of lacewing larvae were unaffected by any of the insecticide treatments. Syrphid larvae were the most abundant aphid predator and Episyrphus balteatus the most common species. Ladybirds (Coccinella septempunctata and Propylea quatuordecimpunctata) were less numerous and only a few Chrysoperla carnea larvae were recorded. These results indicate that products that are less toxic to syrphid larvae, like esfenvalerate and fluvalinate, may be preferable to other compounds to control cereal aphids in wheat in spring and early summer. However, other criteria, such as the effectiveness of the different aphid‐specific predators, cost, efficacy of the treatment and side effects on other aphid antagonists (including parasitic hymenoptera and polyphagous predators) must also be taken into consideration. © 2000 Society of Chemical Industry  相似文献   

Two-year surveillance of tilapia lake virus (TiLV) reveals its wide circulation in tilapia farms and hatcheries from multiple districts of Bangladesh     

Partho Pratim Debnath  Jerome Delamare-Deboutteville  Mona Dverdal Jansen  Kornsunee Phiwsaiya  Afsana Dalia  Md. Abir Hasan  Saengchan Senapin  Chadag Vishnumurthy Mohan  Ha Thanh Dong  Channarong Rodkhum 《Journal of fish diseases》2020,43(11):1381-1389

Tilapia lake virus (TiLV) is an emerging pathogen in aquaculture, reportedly affecting farmed tilapia in 16 countries across multiple continents. Following an early warning in 2017 that TiLV might be widespread, we executed a surveillance programme on tilapia grow-out farms and hatcheries from 10 districts of Bangladesh in 2017 and 2019. Among farms experiencing unusual mortality, eight out of 11 farms tested positive for TiLV in 2017, and two out of seven tested positive in 2019. Investigation of asymptomatic broodstock collected from 16 tilapia hatcheries revealed that six hatcheries tested positive for TiLV. Representative samples subjected to histopathology confirmed pathognomonic lesions of syncytial hepatitis. We recovered three complete genomes of TiLV from infected fish, one from 2017 and two from 2019. Phylogenetic analyses based on both the concatenated coding sequences of 10 segments and only segment 1 consistently revealed that Bangladeshi TiLV isolates formed a unique cluster within Thai clade, suggesting a close genetic relation. In summary, this study revealed the circulation of TiLV in 10 farms and six hatcheries located in eight districts of Bangladesh. We recommend continuing TiLV-targeted surveillance efforts to identify contaminated sources to minimize the countrywide spread and severity of TiLV infection.  相似文献   

Assessment of Bioactive Potential of Aqueous Protein Extracts from Diatoms Nitzschia laevis,Spirulina platensis,and Chlorella vulgaris     

Mona Ahmed J. Alzahrani  Rasangani Sabaragamuwa  Yacine Hemar 《Journal Of Aquatic Food Product Technology》2019,28(2):177-193

The bioactivities of protein extracts from Nitzschia laevis, Spirulina platensis, and Chlorella vulgaris were evaluated in vitro. Free radical scavenging potential, reducing power, oxygen radical absorbance capacity, superoxide anion radical, xanthine oxidase inhibition, and potential to inhibit angiotensin 1-converting enzyme (ACE) and acetylcholinesterase enzyme (AChE) were studied. Nitzschia protein extracts showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, reducing power, and ACE inhibitory activity. Spirulina’s proteins showed the highest 2,2′-Azino-bis (3 ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity, xanthine oxidase, and AChE inhibition activities. Aqueous protein extracts from Nitzschia, Spirulina, and Chlorella showed in vitro antioxidant, anti-ACE, and anti-AChE activities, suggesting possible new sources of bioactive proteins of different phyla with nutraceutical and pharmaceutical potentials.  相似文献   

Direct-fed microbes: A tool for improving the utilization of low quality roughages in ruminants     

Mona M Y Elghandour  Abdelfattah Z M Salem  Jose S Martínez Castaneda  Luis M Camacho  Ahmed E Kholif  Juan C Vázquez Chagoyán 《农业科学学报》2015,14(3):526-533

For many years, ruminant nutritionists and microbiologists have been interested in manipulating the microbial ecosystem of the rumen to improve production efficiency of different ruminant species. Removal and restriction of antibiotics subtherapeutic uses from ruminant diets has amplified interest in improving nutrient utilization and animal performance and search for more safe alternatives. Some bacterial and fungal microorganisms as a direct-fed microbial(DFM) can be the most suitable solutions. Microorganisms that are commonly used in DFM for ruminants may be classified mainly as lactic acid producing bacteria(LAB), lactic acid utilizing bacteria(LUB), or other microorganism's species like Lactobacillus, Bifidobacterium, Enterococcus, Streptococcus, Bacillus, Propionibacterium, Megasphaera elsdenii and Prevotellabryantii, in addition to some fungal species of yeast such as Saccharomyces and Aspergillus. A definitive mode of action for bacterial or fungal DFM has not been established; although a variety of mechanisms have been suggested. Bacterial DFM potentially moderate rumen conditions, and improve weight gain and feed efficiency. Fungal DFM may reduce harmful oxygen from the rumen, prevent excess lactate production, increase feed digestibility, and alter rumen fermentation patterns. DFM may also compete with and inhibit the growth of pathogens, immune system modulation, and modulate microbial balance in the gastrointestinal tract. Improved dry matter intake, milk yield, fat corrected milk yield and milk fat content were obtained with DFM administration. However, the response to DFM is not constant; depending on dosages, feeding times and frequencies, and strains of DFM. Nonetheless, recent studies have supported the positive effects of DFM on ruminant performance.  相似文献   

Health monitoring of plants by their emitted volatiles: A model to predict the effect of Botrytis cinerea on the concentration of volatiles in a large-scale greenhouse     

R.M.C. Jansen  J.W. Hofstee  J. Wildt  B.H.E. Vanthoor  F.W.A. Verstappen  K. Takayama  H.J. Bouwmeester  E.J. van Henten 《Biosystems Engineering》2010,106(1):37-47

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Establishment limitation of holm oak (Quercus ilex subsp. ballota (Desf.) Samp.) in a Mediterranean savanna — forest ecosystem     

Christian Smit  Mario Díaz  Patrick Jansen 《Annals of Forest Science》2009,66(5):511-511

? Tree recruitment in Mediterranean savannas is generally hampered, in contrast with the original oak forests where these savannas are derived from. We asked whether this difference in recruitment success can be explained by differential post-dispersal survival. For one year we monitored experimentally cached holm oak acorns in a savanna — forest ecosystem in Central Spain, and recorded cache pilferage, type of pilferer, boar rooting, seedling emergence, seedling survival and the cause of mortality.

? Cache pilferage was significantly lower in savanna (8%) than in forest (21%). However, the higher cache survival was more than offset by lower seedling emergence and, particularly, by nine times higher seedling mortality in savanna, mainly due to desiccation. Wild boar rooting did not differ between experimental caches and controls without acorns, indicating that individual cached acorns do not trigger rooting activity.

? Our results indicate that the difference in post-dispersal survival between savanna and forest is due to lower emergence and, primarily, higher seedling mortality in savanna, not to higher cache pilferage. Absence of safe sites such as shrubs, abundantly present in the forest, may well explain the lack of recruitment in the savanna. Management measures appear necessary for long-term persistence of Mediterranean savannas in general.

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