To quote my old pal Jon Gritton "Whoa.... Google's bold text just changed font"
And yes, a quick check in Google UK indeed confirms that both the organic and paid (Ads) text now highlights the search term in bold text.
This is a significant change to the Google Search Engine Results Pages (SERPs) and now almost certainly increases the value of Meta Description tags within each page. So expect the Search Engine Optimisation and Paid Ads community to be excited and full of recommendations to take advantage of this alteration.