Optical diffraction study of muscle fibers: I. A theoretical basis

We present a simple theoretical model of optical diffraction by striated muscle fibers. The model accounts for (1) changes in diffraction intensity during isometric contraction, (2) spectra of quasielastically scattered light from isometrically contracting muscle, and (3) an electro-optical effect or intensity modulation of diffraction lines by applied electric field. Items (1) and (2) are concerned with the fluctuations of the sarcomere structure during isometric contraction, and item (3) is concerned with the lateral motions of, or the flexibility of, thin filaments in striated muscle at rest.     

Suppression of Growth of Herpes Simplex Virus in Chick Embryo Fibroblasts at 40 C

Four strains of herpes simplex virus tested all showed inability to form plaques in chick embryo fibroblasts (CEF) at 40 C, while no such suppression of growth was observed with WEE, vaccinia or JE virus in the same cells. The suppression was not due to a complete inhibition of viral growth, because virus-infected CEF bottle cultures consistently showed a small but definite increase of virus titer in 24 hr. When CEF monolayers adsorbing herpes virus were placed at 40 C, the number of infective centers decreased gradually; however, this decrease was much slower than the degradation of free virus at this temperature. Transfer of virus-infected CEF bottle cultures from 35 C to 40 C at any time during a one step growth cycle promptly slowed down subsequent virus replication. When virus-infected CEF bottles were incubated first at 40 C for 24 hr and then transferred to 35 C, a new increase in virus titer took place following a short lag. What stage of virus replication is suppressed at 40 C remains yet to be determined.     

Elbow-joint morphology as a guide to forearm function and foraging behaviour in mammalian carnivores

Among the hunting strategies employed by members of the order Carnivora (Mammalia), two, stalk and ambush and sustained pursuit, are particularly prevalent among larger species of the order. It has been difficult to identify morphological traits that support this distinction and ecological observations have shown that most carnivorans adopt a continuum of strategies, depending on available habitat and prey. In this paper, the shape of the distal humerus articulation is analysed, with the aim of exploring the use of the forelimb in prey procurement, and as a guide to such behaviour among fossil carnivorans. The results suggest that manual manipulation and locomotion are conflicting functions. Elbow‐joint morphology supports a division between grapplers (i.e. ambushers) and nongrapplers (i.e. pursuers). Joints of the former are characterized by being relatively wide and the latter, by being relatively narrow and box‐like with pronounced stabilizing features. At intermediate and large body sizes, carnivorans show a pattern suggesting mutually exclusive feeding strategies that involve either grappling with prey or sustained pursuit. The former allows for large body sizes, such as pantherine felids and ursids; the latter includes species of only moderate size, such as hyenids and canids. Elbow‐joint morphology is closely linked to phylogeny, but the morphology of the cheetah converges with that of nongrapplers, showing that strong selective forces may override the phylogenetic component. Two taxa of giant mustelids from the Miocene were analysed to test whether this sort of analysis is applicable to carnivorans of the past. The African Late Miocene species Ekorus ekakeran has a joint morphology comparable to that of modern‐day nongrapplers. Two joint morphologies were found in the North American Late Oligocene‐Early Miocene Megalictis ferox. The first morphology is comparable to that of modern pantherine cats and the second forms an intermediate between grapplers and nongrapplers that is not present in the modern carnivoran fauna. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142 , 91–104.     

Optical diffraction study of muscle fibers. II. Electro-optical properties of muscle fibers.

When an electric field is applied along the fiber axis, the intensities of all observable optical diffraction lines of skeletal muscle fibers increase. This electro-optical effect was extensively studied and it was confirmed that the effect is due to the interaction between electric dipole moments of thin filaments and the applied field. From the present study on the intensity modulation due to applied field in sinusoidal and square forms, we confirmed that (1) the thin filament is a semiflexible rod, (2) the second order mode of the bending motion of thin filaments contributes to the electro-optical effect of muscle fibers at higher frequencies of a sinusodidal field or shorter durations of a square field, (3) the induced moment has no appreciable effect, and (4) the estimated value of the flexural rigidity of thin filaments strongly depends on the concentrations of free calcium ions in the myofibrillar space.     

Lipase activity in the hemolymph of Biomphalaria glabrata (Mollusca) challenged with bacterial lipids

The levels of lipase activity in both the cellular and serum constituents of the hemolymph of Biomphalaria glabrata that had been challenged in vitro to beat-killed and sonicated Bacillus megaterium as well as samples challenged with live B. megaterium were ascertained. There were no significant alterations in the levels of enzyme activity in both cells and serum of the samples that had been challenged with sonicated bacteria; however, there was a signficant elevation in the enzyme activity associated with both the cells and serum of hemolymph that had been challenged with live bacteria. It has been concluded that live B. megaterium can stimulate hypersynthesis of lipase, a lysosomal enzyme, in phagocytes of B. glabrata and that this enzyme subsequently is released into serum. Consequently, the hydrolysis of lipid constituents of bacteria could theoretically occur in serum as well as within phagocytes.     

The Ultrastructure of Circulating Hemolymph Cells of the Marine Snail Cerithidea californica (Gastropoda: Prosobranchiata)

Two morphologically distinct blood cell-types, the granulocyte and hyalinocyte, are found in the hemolymph circulation of the marine prosobranch Cerithidea californica. Granulocytes, measuring 12.7 µ (9.0–15.0 µ) in diameter, possess well-defined ectoplasmic and endoplasmic regions of the cytoplasm, granules of moderate to heavy electron density, tubular rough endoplasmic reticulum (RER), short vesicles of smooth endoplasmic reticulum (SER), and a large cytoplasm to nucleus ratio. Two morphological variants of this cell-type are distinguished depending upon the presence or absence of dense granules or RER. Hyalinocytes, measuring 5.3 µ (4.0–8.0 µ) in diameter, are distinguished from gran ulocytes by possessing a smaller cytoplasm to nucleus ratio and a general lack of dense cytoplasmic granules and SER.     

A new silverside, <Emphasis Type="Italic">Atherinomorus aetholepis</Emphasis> sp. nov., from the West Pacific (Atheriniformes: Atherinidae)

Atherinomorus aetholepis sp. nov. is described from the holotype and 51 paratypes, 44–72 mm in standard length, collected from Indonesian and Philippine waters. The species is similar to other congeners in general body appearance, especially A. duodecimalis and A. regina, in having a slender body, a tubercle on the posterior end of the dentary, and a narrow midlateral band, but clearly differing from them in having a long spatular outgrowth on the posterior margins of most of the predorsal and interdorsal scales. Additionally, the species differs from A. duodecimalis in having a more slender body [body depth 17–22 (mean 19) % SL vs. 19–25 (mean 22) % SL], more midlateral scales [37–40 (mean 38.4) vs. 35–38 (mean 36.6)], more total vertebrae [38–42 (mean 39.9) vs. 36–40 (mean 38.0)], and fewer lower gill rakers [18–22 (mean 20.2) vs. 20–25 (mean 22.3)], and from A. regina in having more anal fin soft rays (12–14 vs. 9–10). Electronic supplementary material to this article is available at and accessible to authorized users. Received: October 22, 2001 / Revised: March 14, 2002 / Accepted: March 26, 2002 An erratum to this article is available at .