Microscopy Masterpieces 

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Fern sporangia 2a (and) MAX_fern 10a – Sorus– a cluster of sporangia and accessory trichomes –     paraphyses – on the underside of a polypody fern (Polypodium virginianum) leaf. Magnification ~100x.

 

Desmids compilation 1 – A composite image showing various species of freshwater green algae, desmids. The cell wall was stained with Calcofluor White, chloroplasts show innate red fluorescence. Magnification: 400x.

 

Desmids mandala 2 – A compilation of images showing several species of freshwater green algae, desmids, shown to scale. The largest (outermost) six are Micrasterias rotata, M. radiosa, M. furcata, M. americana, and two variants of M. truncata. Two innermost Desmids are Euastrum bidentatum and a cosmid. The cell sizes among Desmids vary considerably; the largest one measures 250 microns across, the tiny Cosmarium – only 40 microns. The cell wall was stained with Calcofluor White, chloroplasts show innate red fluorescence.

 

Diving beetle foot – Front foot (tarsus) of a diving beetle Acilus sulcatus. The structures covering it evolved as a means of attaching to the back of a female during and after mating (a behavior called “mate guarding”). Female diving beetles don’t like giving piggyback rides to males; they want to be able to mate with multiple partners, and also attached males steal some food females catch, and so the females evolved structures on their thoraxes that make it more difficult for the males to stay attached.  That in turn drove further adaptation of male appendages. Inter-sexual arms race led to the foot being equipped with several sets of suction cups of various sizes. The Acilius diving beetle tarsus is ~2 mm in diameter; the image is a mosaic of 4 tailed projections.

 

Dog+and+Lonestar+ticks+from+Janelia+campus – mouthparts of a Brown dog tick (Rhipicephalus sanguineus; front) and a Lone star tick (Amblyomma americanum), ventral side. Cuticle stained with Congo Red and Calcofluor White. Colors represent varied affinity of the insect’s exoskeleton to chitin-binding dyes reflecting different structural properties of chitin. Jagged structure in the center is hypostome, the digits of chelicerae are visible as hook-like blades near hypostome’s top; palps flank the structure from both sides. Length 1 mm; maginification ~100x.

 

Fern sporangia 2a (and) MAX_fern 10a – Sorus – a cluster of sporangia and accessory trichomes – paraphyses – on the underside of a polypody fern (Polypodium virginianum) leaf. Magnification ~100x

 

Humped bladderwort trap interior 2 – Confocal stack projection showing frontal section through  the trap – or bladder – of an aquatic carnivorous plant, Humped bladderwort (Utricularia gibba). The The four bright vertical elements visible above the mouth-like entrance to the trap are the bases of trigger hairs. A prey – usually a crustacean, nematode worm or an insect, such as mosquito larva – is guided towards the ‘mouth’ by antenna-like protrusions and sucked in within a millisecond upon touching the trigger hairs. Several elements of the bladder’s construction are visible in the image, giving some insight into working of this tiny – only 1.5 mm long – but elaborate suction trap. The driving force behind the trapping mechanism is hydrostatic pressure: the plant “cocks” the trap by pumping water out of the bladder, accumulating potential energy in its thick and flexible walls like in the limbs of a bow. Specialized cells called bifid and quadrifid glands are responsible for the task of active transport of water. They line the inner walls and are visible in the image as bright-purple elongated shapes. Once inside, the prey dies of anoxia and is digested by enzymes secreted by the bifid and quadrifid glands. The intricately shaped objects visible in the lower part of the image are those aforementioned green algae called desmids; two species belonging to the genus Micrasterias and three species of Staurastrum can be identified. Various authors have described algae in Utricularia traps as commensals (algae that thrive and propagate in the nutrient-rich interior of the trap), symbionts (bladderwort benefits from the carbohydrates produced by algae) or as prey. Recent studies show that algae are able to survive only inside older, inactive traps; more than 90% are killed inside vivid, young traps. It may be that late in the season when I collected the specimens, most of the traps were already inactive, which could explain why the trapped desmids seemed to be doing fine. Magnification: 100x; Colors: blue and green – cellulose stained with Calcofluor white; red – autofluorescence of chloroplasts.

 

Moth proboscis – Median – inner – side of a moth proboscis (Geometridae sp.). Cuticle stained with Congo Red and Calcofluor White. Colors represent varied affinity of the insect’s exoskeleton to chitin-binding dyes reflecting different structural properties of chitin. The proboscis is covered in mechano- and chemo-sensory hairs. Length 0.8 mm, magnification ~100x.

 

Snail radula 2 – Radula; or simply a tongue; of a freshwater snail. The array of tiny chitinous teeth; each only 30 microns in length; is used to scrape algae. Depth color-coded projection of a confocal stack taken at ~400x magnification

 

Stentors 2 – The image shows three single-cell freshwater microorganisms known as Stentors. Those iconic protozoa are covered in hair-like organelles called cilia; the shorter ones are used for swimming, longer – feeding. The segmented macronucleus has an appearance of beads on a string, shown in bluish-purple hues. To visualize those structures with a confocal microscope I used antibodies against acetylated tubulin that is abundant in the cilia, and DAPI, a blue-fluorescent dye with an affinity to DNA. The largest Stentor in the trio is ~250 microns long.