Phylogeography of the leaf beetle Chrysolina virgata in wetlands of Japan inferred from the distribution of mitochondrial haplotypes

The genetic differentiation among populations of the leaf beetle Chrysolina virgata living in wetlands of Japan was studied based on the sequence data of the mitochondrial cytochrome oxidase subunit I gene region (750 bp). Two distinct lineages of mitochondrial haplotypes were found: one (clade A) consisted of 26 haplotypes distributed over the distribution range of C. virgata between north‐east Honshu and Kyushu, whereas the other (clade B) was monotypic and confined to a small region in north‐east Honshu where it coexisted with clade A. Nested clade analysis for these haplotypes suggested that range expansion and following differentiation due to isolation by distance might have resulted in the present distribution pattern of the haplotypes in clade A. We discuss the evolutionary process leading to the occurrence of two distinct haplotype clades in Japan in terms of repeated colonization from the continent and range expansion and contraction during climatic changes.     

DIRECT ISOLATION OF NATIVE THIN FILAMENTS FROM EMBRYONIC MUSCLE CELLS*

A method is presented for the release of “native” thin filaments from 13-day old embryonic chick muscle without tryptic digestion or desoxycholate (DOC) solubilization of Z bands. The isolated filaments were 50–60 Å in diameter, of variable length, and formed “arrowhead-like” complexes with heavy meromyosin (HMM). In addition, the filaments interacted with purified myosin to form actomyosin as effectively as action extracted from an acetone powder of muscle. The Mg⁺⁺-dependent ATPase activity and extent of superprecipitation of the synthetic actomyosin required a low concentration of Ca⁺⁺, strongly suggesting the presence of troponin and tropomyosin on the thin filaments isolated from muscle at this stage of embryogenesis. The native thin filaments were more sensitive to trypsin than synthetic F-actin prepared from an acetone powder based on measurements of flow birefrengence, viscosity and the ability to activate myosin ATPase.     

Circadian Motile Activity of Erythrophores in the Red Abdominal Skin of Tetra Fishes and Its Possible Significance in Chromatic Adaptation

The red abdominal skin of the neon tetra Paracheirodon innesi and the cardinal tetra P. axelrodi was found to blanch at night or in the dark. Melatonin added to the bathing medium caused blanching of the red skin. Microscopic observations of the erythrophores indicated that the erythrosomes aggregated in response to norepinephrine, melanin-concentrating hormone (MCH), and melatonin. Of these compounds, melatonin was the most effective. By contrast, many erythrophores were refractory to MCH. Alpha-melanophore-stimulating hormone, isoproterenol, adenosine, and ATP each caused dispersal of the pigment to some extent. Isoproterenol dispersed the pigment only when an alpha-adrenergic blocker, tolazoline, was present. It appears that the change in color of the abdominal skin is primarily due to increased secretion during the night of the pineal hormone melatonin, while other hormonal and nervous factors may modify the distribution of the pigment in the erythrophores.     

Convergence of insular dwarfism in damselflies (Euphaea) and dobsonflies (Protohermes)

SUMMARY. 1. The life history was compared between mainland and island congeners of Protohermes (Megaloptera: Corydalidae) and also between those of Euphaea (Odonata: Euphaeidae). Larvae of these genera coexisted in stream riffles, and prey availability for them was assessed to examine the effects on their body size at maturation.
2. Body size of P. costalis on the 'mainland'. Taiwan, was larger than that of an insular congener, P . sp., on Iriomotc and Ishigaki Islands about 200 km east from Taiwan. Insular dwarfism also occurred between E. formosa on the mainland and E. yayeyamana on the islands. All species had an annual life cycle.
3. Prey availability was much lower in the island streams than in mainland streams throughout the year. Convergence of insular dwarfism in these phylogenetically distant but ecologically similar taxa (both predatory insects) suggested that prey availability is an important factor affecting their body size determination.
4. Seasonal changes in body size occurred within a population of Euphaea which lacked synchronous emergence. Adults emerging from larvae spending their late instars in the warm season were smaller than those in the cold season. However, the size differences between species always exceeded the range of such intraspecific variation.
5. Dwarfism in E. yayeyamana was probably achieved by decreasing the size of first-instar larvae without changing the number of instars and with the size ratio at each moult constant. The mechanisms producing the dwarf form of Protohermes are also discussed.     

An Ustilago maydis Mutant Partially Blocked in P45014DM Activity Is Hypersensitive to Azole Fungicides

An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole.     

Genetic variants of phosvitin in egg yolk of the Japanese quail, Coturnix coturnix japonica

Summary. Phosvitin polymorphism in egg yolk of the Japanese quail was found by horizontal polyacrylamide gradient gel electrophoresis. Six phenotypes of yolk phosvitin designated A, B, C, AB, AC, and BC were observed in a population of 281 birds. Analysis of family data revealed that the phenotypic variation of quail yolk phosvitins was controlled by an autosomal Pv locus with three codominant alleles, Pv^a, Pv^b and Pv^c. The gene frequencies of Pv^a, Pv^b and Pv^c were 0.064, 0.824 and 0.112, respectively.     

Hexazonium pararosaniline as a fixative for animal tissues

Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution.