Acosta Raquel, Rodríguez-Martín Andrea, Martín Alberto, Núñez Félix, Asensio Miguel A
Higiene y Seguridad Alimentaria, Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad s/n. 10071 Cáceres, Spain.
Int J Food Microbiol. 2009 Sep 30;135(1):39-46. doi: 10.1016/j.ijfoodmicro.2009.07.020. Epub 2009 Jul 28.
To control unwanted molds in dry-cured meats it is necessary to allow the fungal development essential for the desired characteristics of the final product. Molds producing antifungal proteins could be useful to prevent hazards due to the growth of mycotoxigenic molds. The objective has been to select Penicillium spp. that produce antifungal proteins against toxigenic molds. To obtain strains adapted to these products, molds were isolated from dry-cured ham. A first screening with 281 isolates by the radial inhibition assay revealed that 166 were active against some of the toxigenic P. echinulatum, P. commune, and Aspergillusniger used as reference molds. The activity of different extracts from cultured medium was evaluated by a microspectroscopic assay. Molds producing active chloroform extracts were eliminated from further consideration. A total of 16 Penicillium isolates were screened for antifungal activity from both cell-free media and the aqueous residues obtained after chloroform extraction. The cell-free media of 10 isolates that produced a strong inhibition of the three reference molds were fractionated by FPLC on a cationic column. For protein purification, the fractions of the three molds that showed high inhibitory activity were further chromatographed on a gel filtration column, and the subfractions containing the highest absorbance peaks were assayed against the most sensitive reference molds. One subfraction each from strains AS51D and RP42C from Penicilliumchrysogenum confirmed the inhibitory activity against the reference molds. SDS-PAGE revealed a single band from each subfraction, with estimated molecular masses of 37kDa for AS51D and 9kDa for RP42C. Although further characterisation is required, both these proteins and the producing strains can be of interest to control unwanted molds on foods.
为了控制干腌肉中不需要的霉菌，有必要让真菌生长，这对于最终产品的理想特性至关重要。产生抗真菌蛋白的霉菌可能有助于预防由产毒霉菌生长引起的危害。目标是筛选出能产生针对产毒霉菌的抗真菌蛋白的青霉属菌株。为了获得适应这些产品的菌株，从干腌火腿中分离霉菌。通过径向抑制试验对281个分离株进行初步筛选，结果显示其中166个对用作参考霉菌的一些产毒的棘孢青霉、普通青霉和黑曲霉有活性。通过显微光谱分析评估了来自培养基的不同提取物的活性。产生活性氯仿提取物的霉菌不再进一步考虑。从无细胞培养基和氯仿提取后得到的水相残余物中筛选了总共16个青霉分离株的抗真菌活性。对10个对三种参考霉菌有强烈抑制作用的分离株的无细胞培养基在阳离子柱上进行快速蛋白质液相色谱分离。为了进行蛋白质纯化，对三种霉菌中显示出高抑制活性的数据进行进一步的凝胶过滤柱色谱分离，并针对最敏感的参考霉菌检测含有最高吸光度峰的亚组分。产黄青霉的AS51D和RP42C菌株各有一个亚组分证实了对参考霉菌的抑制活性。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示每个亚组分有一条带，AS51D的估计分子量为37kDa，RP42C的为9kDa。尽管需要进一步表征，但这些蛋白质和产生菌株对于控制食品中不需要的霉菌可能都具有重要意义。
