When we casually gob onto a pavement or a sport’s field, how many of us ever take time to consider the truly wonderful nature of saliva. Our saliva is 99.5% water, with the other important 0.5% comprising electrolytes, mucus, glycoproteins, enzymes, antibacterial compounds such as lysozyme. Various enzymes naturally present in saliva initiate the processes of digestion and begin to breakdown food. Saliva also serves as a lubricant, wetting food and thus permitting swallowing, and also protects the mucosal surfaces of the oral cavity from desiccation. It also bathes and nourishes the oral microbiome (that is the natural bacterial microflora of the mouth).
The various images here were taken during a workshop at ASCUS (@_ASCUS ) that I ran, and are of participants saliva imaged after a DIY staining method that I developed and using a portable Newton field microscope and my iPhone.
Below is an image of the field microscope used
Below are the stained spit specimens on glass microscope slides as visible to the human eye
Below are the same slides as imaged by the microscope.You can clearly see cheek epithelial cells from the people taking part and with the darker stained nuclei that contained the participants genomes. The tiny specks are mostly bacteria from the oral microbiome.
For comparison the image below was taken of my own spit after the same DIY staining process but instead using a powerful laboratory microscope. The lab microscope does produce a better image but it cost £30,000 and is a lab-bound beast that cannot be taken on expeditions. In comparison, the field microscope, which costs around £500, does a pretty good job.
Finally, whilst still on the subject of spit, please follow the link below to see another version of Cellfies, with artist Heather Barnett and myself, in which we used a Differential Interference Contrast microscope to image spit specimens from both of us. The advantage of this microscope is that it allows us to see cells in detail and without staining, and in a way that the cells stay alive and active. In the video you can see bacteria from the mouth, epithelial cells, and immune cells called neutrophils in action.
The video can be seen at the Menagerie of Microbes exhibition (#MenagerieOfMicrobes) at @Summerhallery as part of @EdSciFest