Arion lusitanicus and other slugs are able to feed on a variety of plants, even those containing toxic secondary metabolites, such as alkaloids. Alkaloids, like sparteine, lupanine, quinidine and atropine are avoided in no-choice feeding experiments only when they are present in concentrations above 1 mg/g food pellet. Alkaloids (sparteine, lupanine, cytisine, quinidine, atropine, senecionine, eserine, and harmaline) are toxic to Arion lusitanicus when injected. LD 50 values are 10 to 20 fold higher than in vertebrates indicating that slugs have a high tolerance towards food toxins. The tolerance is higher in young animals than in adult slugs. Injected alkaloids are rapidly detoxified within 72 h. Tolerance and detoxification can be induced by feeding slugs on non-lethal doses of lupin alkaloids. Using isolated microsomal preparations from the digestive gland, active detoxification was observed in vitro. Evidence is presented that cytochrome p450 plays an important role in detoxification of the applied alkaloids. A powerful and inducible detoxification systems appears to be the main mechanism that allows slugs to feed on plants rich in secondary metabolites (when no other food is available), that are usually avoided by other herbivores.

Three different methods for the culture of rumen microorganisms (Hungate's technique, the Hohenheim in vitro gas production method, and the semicontinuous rumen simulation technique) were employed to study the influence of various alkaloids (sparteine, lupanine, cytisine, atropine, quinidine, lobeline, harmaline, arecoline, nicotine, caffeine, pilocarpine, gramine, senecionine, and monocrotaline) on rumen microorganisms. Rumen micro-organisms from naive ruminants (sheep, cattle) that had not been exposed to the alkaloids before were generally not able to degrade most of the alkaloids. Only the alkaloids pilocarpine, gramine, and monocrotaline appeared to be degradable. Rumen microorganisms from a sheep preconditioned to lupin alkaloids tolerated lupanine much better than nonadapted microorganisms, but no degradation occurred. The findings indicate that the main site of detoxification in naive ruminants is not the rumen but more likely the liver and kidneys as in nonruminants.

Colorado and Wyoming lakes with high pH values generally ranging from 8 to 10 are dominated by phytoplankton belonging to the chrysophytes, diatoms and cryptomonads. Our studies on phytoplankton diversity in Dowdy, South Delaney Buttes and Cowdrey Lakes in Colorado and Diamond and Twin Buttes Lakes in Wyoming have yielded several isolates of rare or new chrysophytes. These isolates were examined with light microscopy, SEM, TEM, and novel information regarding their structure is presented. Proposed new species belong to the genera Saccochrysis, Prymnesium and Chrysochromulina. Chrysophytes that were examined for the first time include Monochrysis aphanaster, Uroglenopsis, and a mixotrophic species of Ochromonas, which ingests small diatoms. Probable new species are the following: Saccochrysis sp. nov. differs in chloroplast structure, cell shape and cell number/colony, and absence of a posterior vacuole; Prymnesium sp. nov. is the first freshwater form examined with EM and differs in scale morphology; and Chrysochromulina sp. nov. is similar to Chrysochromulina parva but lacks scales. The ultrastructure of M. aphanaster is unique and appears to be a member of the Chrysophyceae. It has two flagella, one of which is emergent, while the other is hidden within an invagination of the cytoplasm. Diacronema and Sarcinochrysis spp. from these lakes also were isolated and reinvestigated, and some unique cellular features will be discussed.

Electron microscopic examinations of numerous isolates from Colorado lakes and reservoirs have revealed several new genera and species. Based on the furrow/gullet variations and the structure of the periplast, four new genera are proposed. These new genera and their characteristics are as follows. The first genus has a furrow without a gullet, and it has oval periplast plates. There are two chloroplasts per cell and two nucleomorphs located anterior to the chloroplasts in the periplastidial compartment. Pyrenoids are lacking. Chloroplasts contain phycoerythrin 566. The second genus is similar in shape and structure to Plagioselmis, but it has small rectangular plates rather than hexagonal plates. There is one dorsal chloroplast per cell, with a single stalked pyrenoid, which is not traversed by thylakoids and associated with two starch plates. The nucleomorph is posterior to the pyrenoid and is located between the nucleus and pyrenoid. Chloroplasts contain phycoerythrin 566. The third genus lacks a gullet and furrow and has an inner periplast sheet. Cells have two chloroplasts without pyrenoids, and the chloroplasts contain phycoerythrin 566. The nucleomorphs are located in the anterior portion of the plastidial compartment. The fourth genus is blue‐green in color, it lacks a furrow/gullet, and the internal and surface periplast components consist of hexagonal plates. Cells have a large pyrenoid that protrudes ventrally into the cytoplasm and is traversed by numerous paired thylakoids. The nucleomorph is situated lateral to the pyrenoid. Chloroplasts contain phycocyanin 645. This cryptomonad was previously identified as Chroomonas pochmanni, and it is mixotrophic.