Selection of reference genes to quantify relative expression of ochratoxin A-related genes by Penicillium nordicum in dry-cured ham

The ecological conditions during the ripening of dry-cured ham favour the development of moulds on its surface, being frequently the presence of Penicillium nordicum, a producer of ochratoxin A (OTA). Biocontrol using moulds and yeasts usually found in dry-cured ham is a promising strategy to minimize this hazard. The aim of this work is to evaluate the effect of previously selected Debaryomyces hansenii and Penicillium chrysogenum strains on growth, OTA production, and relative expression of genes involved in the OTA biosynthesis by P. nordicum. P. nordicum was inoculated against the protective cultures individually and combined on dry-cured ham for 21 days at 20 °C. None of the treatments reduced the growth of P. nordicum, but all of them decreased OTA concentration. The lower production of OTA could be related to significant repression of the relative expression of otapksPN and otanpsPN genes of P. nordicum. The efficacy of the combined protective cultures was tested in 24 dry-cured hams in industrial ripening (an 8 month-long production). OTA was detected in nine of the 12 dry-cured hams in the batch inoculated only with P. nordicum. However, in the batch inoculated with both P. nordicum and the combined protective culture, a considerable reduction of OTA contamination was observed. In conclusion, although the efficacy of individual use P. chrysogenum is great, the combination with D. hansenii enhances its antifungal activity and could be proposed as a mixed protective culture to control the hazard of the presence of OTA in dry-cured ham.

Download Full-text

Penicillium Populations in Dry-Cured Ham Manufacturing Plants

Journal of Food Protection ◽

10.4315/0362-028x-70.4.975 ◽

2007 ◽

Vol 70 (4) ◽

pp. 975-980 ◽

Cited By ~ 82

Author(s):

PAOLA BATTILANI ◽

AMEDEO PIETRI ◽

PAOLA GIORNI ◽

SILVIA FORMENTI ◽

TERENZIO BERTUZZI ◽

...

Keyword(s):

Relative Humidity ◽

Ochratoxin A ◽

Potential Risk ◽

Dominant Species ◽

Surface Contamination ◽

Curing Conditions ◽

Manufacturing Plants ◽

Dry Cured Ham ◽

Penicillium Nordicum

Seven ham manufacturing plants were sampled for 1 year to assess the mycoflora present in the air and on hams, with special attention given to potential mycotoxin producers. Temperature and relative humidity were recorded in the ripening rooms. Maturing rooms held hams from 2 to 3 through 6 to 7 ripening months, and aging rooms held hams for the following 6 to 7 months, until the 14-month ripening point, when they were ready for the market. Mean temperatures and relative humidities registered during the study were 14.9°C and 62.4%, respectively, in maturing rooms and 16.3°C and 57.6% in aging rooms. Aspergilli and penicillia, potential mycotoxin producers, were isolated in all the plants from the air and the ham. Aspergilli represented 5% of the isolates, while penicillia were largely dominant, with Penicillium nalgiovense being the most represented species (around 60% of the penicillia), followed by Penicillium nordicum, with 10 and 26% of the penicillia isolated, respectively, from the air or the ham. Ochratoxin A production ability, checked in vitro at 25°C, was observed in 50% of the P. nordicum isolates obtained both from the air and the ham. Air and ham surface contamination by penicillia was greater in the ripening rooms, where higher temperatures were registered. A certain correlation was also observed between air and ham surface contamination. On the basis of this study, P. nordicum, the ochratoxin A producer that is notable on proteinaceous substrates, is normally present in ham manufacturing plants in Italy, even though not a dominant species. Further studies are necessary to clarify and ensure if dry-curing conditions minimize the potential risk of ochratoxin A formation in the product.

Download Full-text

Biocontrol of Penicillium nordicum Growth and Ochratoxin A Production by Native Yeasts of Dry Cured Ham

Toxins ◽

10.3390/toxins4020068 ◽

2012 ◽

Vol 4 (2) ◽

pp. 68-82 ◽

Cited By ~ 42

Author(s):

Roberta Virgili ◽

Nicoletta Simoncini ◽

Tania Toscani ◽

Marco Camardo Leggieri ◽

Silvia Formenti ◽

...

Keyword(s):

Ochratoxin A ◽

Dry Cured Ham ◽

Penicillium Nordicum

Download Full-text

The influence of salt (NaCl) on ochratoxin A biosynthetic genes, growth and ochratoxin A production by three strains of Penicillium nordicum on a dry-cured ham-based medium

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2014.03.007 ◽

2014 ◽

Vol 178 ◽

pp. 113-119 ◽

Cited By ~ 49

Author(s):

Alicia Rodríguez ◽

Ángel Medina ◽

Juan J. Córdoba ◽

Naresh Magan

Keyword(s):

Ochratoxin A ◽

Biosynthetic Genes ◽

Dry Cured Ham ◽

Penicillium Nordicum

Download Full-text

Influence of ochratoxin A on adaptation of Penicillium nordicum on a NaCl-rich dry-cured ham-based medium

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2018.02.020 ◽

2018 ◽

Vol 272 ◽

pp. 22-28 ◽

Cited By ~ 8

Author(s):

Josué Delgado ◽

Lucía da Cruz Cabral ◽

Mar Rodríguez ◽

Alicia Rodríguez

Keyword(s):

Ochratoxin A ◽

Dry Cured Ham ◽

Penicillium Nordicum

Download Full-text

The Selection of Reference Genes for Quantitative Real-Time PCR in the Ashidan Yak Mammary Gland During Lactation and Dry Period

Animals ◽

10.3390/ani9110943 ◽

2019 ◽

Vol 9 (11) ◽

pp. 943 ◽

Cited By ~ 4

Author(s):

Xiaoyun Wu ◽

Xuelan Zhou ◽

Xuezhi Ding ◽

Min Chu ◽

Chunnian Liang ◽

...

Keyword(s):

Gene Expression ◽

Mammary Gland ◽

Real Time ◽

Milk Yield ◽

Reference Genes ◽

Quantitative Polymerase Chain Reaction ◽

Expression Stability ◽

Dry Period ◽

Relative Expression ◽

Selection Of

Investigating the critical genes related to milk synthesis is essential for the improvement of the milk yield of the yak. Real-time quantitative polymerase chain reaction (RT-qPCR) is a reliable and widely used method to measure and evaluate gene expression levels. Selection of suitable reference genes is mandatory to acquire accurate normalization of gene expression results from RT-qPCR. To select the most stable reference genes for reliable normalization of mRNA expression by RT-qPCR in the mammary gland of the Ashidan yak, we selected 16 candidate reference genes and analyzed their expression stability at different physiological stages (lactation and dry period). The expression stability of the candidate reference genes was assessed using geNorm, NormFinder, BestKeeper, Delta Ct, and RefFinder methods. The results showed that the hydroxymethylbilane synthase gene (HMBS) and the tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide gene (YWHAZ) were the most stable genes across all treatment samples. The reliability of selected reference genes was validated by normalizing relative expression of the lactation-related 60S ribosomal protein L35 gene (RPL35). The relative expression of RPL35 varied considerably according to the different reference genes. This work provides valuable information to further promote research in the molecular mechanisms involved in lactation and mammary gland development and provides a foundation for the improvement of the milk yield and quality of the Ashidan yak.

Download Full-text

Identification of reliable reference genes for gene expression studies in maternal reproductive tissues and fetal tissues of pregnant cows

10.21203/rs.2.22639/v1 ◽

2020 ◽

Author(s):

Lei Cheng ◽

Jie Yu ◽

Xiuzhong Hu ◽

Min Xiang ◽

Yu Xia ◽

...

Keyword(s):

Gene Expression ◽

Reference Genes ◽

Target Genes ◽

Quantitative Polymerase Chain Reaction ◽

Related Factor ◽

Expression Stability ◽

Relative Expression ◽

Reproductive Tissues ◽

Fetal Tissues ◽

Selection Of

Abstract Background: The relationship between the conceptus and the maternal uterine environment is crucial for the successful establishment and maintenance of pregnancy in cattle. Gene expression analysis of the conceptus and maternal reproductive tissues is a favorable method to assess the embryonic maternal interaction. The reliability of the commonly used method reverse transcription-quantitative polymerase chain reaction (RT-qPCR) depends on proper normalization to stable reference genes (RGs). The objective of this study was to determine the expression stability of ten potential RGs (SUZ12, CNOT11, ACTB, RPL19, RPS9, GAPDH, TBP, HPRT1, SDHA and PPIA) in maternal reproductive tissues and fetal tissues, and to analyze the effect of RG selection on the calculation of the relative expression of target genes. Results: The expression stability of ten potential RGs was analyzed in eight different tissues (caruncular endometrium, intercaruncular endometrium, corpus luteum, ovary, oviduct, mammary gland, embryonic disc and trophoblast) from three pregnant dairy cows. Three programs—GeNorm, NormFinder and Bestkeeper—were used to identify the best RGs. According to all three programs, the most stable RG was CNOT11, whereas the least stable RGs were GAPDH and HPRT1. GeNorm analysis showed that a combination of five RGs (SDHA, PPIA, CNOT11, RPS9 and RPL19) was necessary for appropriate data normalization. However, NormFinder analysis indicated that the combination of CNOT11 and PPIA was the most suitable. When target genes were normalized to these RGs, the relative expression of the Radical S-adenosyl methionine domain containing 2 gene was not affected by the choice of RGs, whereas a large difference was observed in the expression profile of the Nuclear erythroid2-related factor 2 gene between the most stable RGs and least stable RGs. Conclusions: The results indicate that careful selection of RGs is crucial under different conditions, especially for target genes with relatively small fold changes. Furthermore, the results provide useful information for the selection of RGs for evaluating genes affecting bovine reproduction.

Download Full-text