Metabolic Scaling: Exploring the Relation Between Metabolic Rate and Body Size.

We present an alternative to the traditional classroom lecture on the topics of metabolic scaling, allometric relationships between metabolic rate (MR) and body size, and reasons for rejecting Rubner''s surface "law," concepts that students have described as challenging, counterintuitive, and/or mathematical. In groups, students work with published data on MR and body size for species representing all five vertebrate groups. To support the exercise, we developed a worksheet that has students define the concept in their own words, compare different measures of MR, and evaluate plots of MR and mass-specific MR versus body mass for both homeotherms and poikilotherms.

Flipped teaching eased the transition from face-to-face teaching to online instruction during the COVID-19 pandemic.

Due to the COVID-19 pandemic, Rice University canceled classes for the week of March 9-13, 2020 and shifted all instruction to online only following spring break. For the second half of the semester, animal physiology was taught exclusively over Zoom. Here we describe how a flipped teaching format that was used before the pandemic eased the transition from face-to-face teaching to online instruction.

Modular laboratory courses: An alternative to a traditional laboratory program.

Our modular laboratory teaching program is characterized by two major features. First, each course is taught independently and not linked with a particular lecture course. Second, each course is designed to be completed within one-half semester or less.

Control of Drosophila perineurial glial growth by interacting neurotransmitter-mediated signaling pathways.

Drosophila peripheral nerves, similar structurally to the peripheral nerves of mammals, comprise a layer of axons and inner glia, surrounded by an outer perineurial glial layer. Although it is well established that intercellular communication occurs among cells within peripheral nerves, the signaling pathways used and the effects of this signaling on nerve structure and function remain incompletely understood. Here we demonstrate with genetic methods that the Drosophila peripheral nerve is a favorable system for the study of intercellular signaling.

A precise group size in Dictyostelium is generated by a cell-counting factor modulating cell-cell adhesion.

A remarkable aspect of Dictyostelium development is that cells form evenly sized groups of approximately 2 x 10(4) cells. A secreted 450 kDa protein complex called counting factor (CF) regulates the number of cells per group. We find that CF regulates group size by repressing cell-cell adhesion.

A protein containing a serine-rich domain with vesicle fusing properties mediates cell cycle-dependent cytosolic pH regulation.

Initial differentiation in Dictyostelium involves both asymmetric cell division and a cell cycle-dependent mechanism. We previously identified a gene, rtoA, which when disrupted randomizes the cell cycle-dependent mechanism without affecting either the underlying cell cycle or asymmetric differentiation. We find that in wild-type cells, RtoA levels vary during the cell cycle.

Electrotransformation of Clostridium acetobutylicum ATCC 824 using high-voltage radio frequency modulated square pulses.

Molecular biological improvement of industrial solventogenic clostridia could be enhanced by a higher efficiency of electrotransformation. In this research, we used a new approach to determine the frequency spontaneously generated by Clostridium acetobutylicum ATCC 824 cells during the application of a square high-voltage pulse. Once the frequency of 100 kHz was determined we transformed clostridial cells with pSOS84 plasmid DNA using radio-frequency modulated high-voltage square pulses (electric field strength 12 kVcm-1; pulse duration 22.

Different temporal patterns of expression result in the same type, amount, and distribution of filamin (ABP) in cardiac and skeletal myofibrils.

The morphogenesis of functional myofibrils in chick skeletal and cardiac muscle occurs in greatly different time spans, in about 7 and 2 days, respectively. In chick skeletal myogenic cells, one isoform of the 250 kD actin-binding protein (ABP) filamin is associated with stress fiber-like structures of myoblasts and early myotubes, then disappears for approximately 4 days, whereupon a second filamin isoform reappears at the Z-disc periphery. We sought to determine if cardiac myogenesis involves this sequence of appearance, disappearance, and reappearance of a new filamin isoform in a compressed time scale.

Association of clathrin with microsomes isolated from canine myocardium.

We and others have observed specialized regions of sarcoplasmic reticulum membranes that resemble coated vesicles, in the I-band region of myocardial cells. These structures have been named "corbular" sarcoplasmic reticulum, and are distinct in appearance from Golgi-associated coated vesicles, in that they are larger and contain a flocculent material that has been identified as calsequestrin. Whereas it has been suggested that these structures have a role in cardiac calcium metabolism, their function(s) and the molecular identity of the characteristic "bristle" coat remain unknown.

Isovolumetric performance of isolated ground squirrel and rat hearts at low temperature.

The effects of low temperature on mechanical performance of the isolated left ventricles of the 13-lined ground squirrel (a hibernator) and the rat (a nonhibernator) were studied. In addition, low-temperature performance of hearts from summer-active, winter-hibernating, and winter-active ground squirrels were compared. By measuring pressure (P) generated against a balloon inserted into the left ventricle, maximum developed pressure (DP) and maximum rate of increase of P (peak dP/dt) were determined over a temperature range of 5-20 degrees C.