A discrete stage-structured model of California newt population dynamics during a period of drought.

We introduce a mathematical model for studying the population dynamics under drought of the California newt (Taricha torosa), a species of special concern in the state of California. Since 2012, California has experienced a record-setting drought, and multiple studies predict drought conditions currently underway will persist and even increase in severity. Recent declines and local extinctions of California newt populations in Santa Monica Mountain streams motivate our study of the impact of drought on newt population sizes.

Mini-hemoglobins from nemertean worms.

Hemoglobins (Hbs) found in members of the phylum Nemertea are smaller than any other known Hb molecules. These mini-Hbs have been of great interest because of their unique three-dimensional structure and their stable ligand-binding properties. Also of interest is the expression of mini-Hb in neural tissue, body wall muscle tissue, and red blood cells.

A HECT domain ubiquitin ligase closely related to the mammalian protein WWP1 is essential for Caenorhabditis elegans embryogenesis.

The highly conserved ubiquitin/proteasome pathway controls the degradation of many critical regulatory proteins. Proteins are posttranslationally conjugated to ubiquitin through a concerted set of reactions involving activating (E1), conjugating (E2), and ligase (E3) enzymes. Ubiquitination targets proteins for proteolysis via the proteasome and may regulate protein function independent of proteolysis.

A High-Affinity Hemoglobin Is Expressed in the Notochord of Amphioxus, Branchiostoma californiense.

In the phylum Chordata, only members of the subphylum Vertebrata were thought to express hemoglobin (Hb). Here we document the existence of intracellular Hb expressed in members of the subphylum Cephalochordata. Hemoglobin is expressed in myotome tissue and in notochord cells within the body of amphioxus.

The mini-hemoglobins in neural and body wall tissue of the nemertean worm, Cerebratulus lacteus.

Hemoglobin (Hb) occurs in circulating red blood cells, neural tissue, and body wall muscle tissue of the nemertean worm, Cerebratulus lacteus. The neural and body wall tissue each express single major Hb components for which the amino acid sequences have been deduced from cDNA and genomic DNA. These 109-residue globins form the smallest stable Hbs known.