I'm curious what the dark blobs are in the photos of the live yeast cells in the paper [1]. They look like what I'd expect organelles to look like but yeast are

I'm curious what the dark blobs are in the photos of the live yeast cells in the paper [1]. They look like what I'd expect organelles to look like but yeast are eukaryotes so I'm guessing coagulation of some sort? I would have thought that bacteria would look much more homogeneous internally, at least at this scale. [1] https://www.nature.com/articles/s41586-021-03528-w.epdf?sharing_token=z589AjKJ21YqsNSgqbqqjtRgN0jAjWel9jnR3ZoTv0Mno9fr00zq_Eu4WL3ds5lODEwwMyzjZ4XzmXvPXaH4CJC4JR0D8qwlies9DwQ9Wl-a-1EnPERl21cvbtn4SwVAf_Fp-GNwh0qk7C3ut-q6rYQ0kXUN90tBriT91ZrzdFp5exUg_ajSNtrjDtN78GPGUq1K4Ik67I7TJXr53oHqgGO8kXkGbEo_QQHj9KMYhVA%3D&tracking_referrer=www.newscientist.com https://www.nature.com/articles/s41586-021-03528-w.epdf?shar...