The calcium response of mouse sperm flagella: role of calcium ions in the regulation of dynein activity

Triton X-100-extracted mouse sperm treated with 0.1 mM ATP and 1.0 mM Ca(2+) exhibit an extremely coiled configuration that has been previously described as a curlicue. Sperm in the curlicue configuration exhibit a monotonically curved flagellum where the shear angle of the flagellum can reach a value as high as 14 radians at the flagellar tip. We utilized this strong reaction to Ca(2+) to elucidate the mechanism of the calcium response. The disintegration of the axoneme was facilitated by the use of an extraction procedure that removed the mitochondrial sheath without eliminating the calcium response. The order of emergence of the doublet microtubule outer dense fiber complexes was observed in the presence and absence of added Ca(2+). The identity of the emergent elements was confirmed by transmission electron microscopy. Ca(2+) altered the order of emergence of internal axoneme elements to favor the appearance of the elements of the 9-1-2 side of the axoneme. These elements are propelled baseward by the action of dyneins on doublets 1 and 2. It was also possible to establish that the motive force for maintaining the curlicue configuration is dynein-based. The curlicues were relaxed by inhibition with 50 μM NaVO(3) and were reestablished by disinhibiting the vanadate with 2.5 mM catechol.     

Phylogeography of Wild Musk Shrew (Suncus Murinus) Populations in Asia Based on Blood Protein/Enzyme Variation

The musk shrew (Suncus murinus) is an insectivore species that inhabits tropical and subtropical Asia widely. To clarify the genetic relationship among wild musk shrew populations, we examined the electrophoretic variants of biparentally inherited genetic markers at 10 loci coding for eight blood proteins/enzymes in a total of 639 animals and compared the results obtained from the mitochondrial DNA data. The principal-component analysis performed using the allele frequency data revealed that the 17 populations could be divided into two major groups, a South Asian group and a Southeast Asian group that includes several island populations bound by Myanmar. The degrees of genetic divergence among populations were higher within the Southeast Asian group than within the South Asian group. This finding was incongruent with the mtDNA diversity. Analysis conducted at the individual level showed that a shrew from the central region in Myanmar that carries a South Asian type of mtDNA showed the electrophoretic variants specific to the Southeast Asian group, suggesting that this region is a contact zone between the two major groups.     

Electron microscopical observations on Kölliker's and Hatschek's pit and on the wheel organ in the head region of Amphioxus (Branchiostoma lanceolatum)

Cell and Tissue Research - Kölliker's and Hatschek's pit and the wheel organ in the head region of Amphioxus have been studied with the electron microscope. Kölliker's pit is...     

In Vivo Production of Neuraminidase by Pasteurella haemolytica in Market Stressed Cattle After Natural Infection

Pasteurella haemolytica (Ph) is the most important cause of the bovine acute fibrinohemorrhagic pneumonia that occurs in market stressed calves after shipment to feedyards. Recent characterization of neuraminidase production by these organisms has shown that all 16 serotypes produce an immunologically similar form of the enzyme. Anti-neuraminidase antibody against PhA1 and PhA6 was determined in 101 2- to 5-month-old calves, on their farms of origin, at the order buyer barn (OBB), and through 28 days in the feedyard. Half of the calves were vaccinated with a killed Ph serotype-A1 (PhA1) product. Nasal secretion and tonsil wash specimens were cultured for Ph and Pasteurella multocida (Pm). Serum antibody against PhA1 and PhA6 was measured by indirect hemagglutination (IHA), and anti-neuraminidase antibody was determined by the neutralization assay. At the feedyard, 73 calves had respiratory tract disease. IHA values ranged between 1:2 and 1:1024 for PhA1 and between 1:2 and 1:512 for Ph serotype A6 (PhA6). Forty-two, 24, and 28% of the calves were infected with PhA1, PhA6, and Pm, respectively. Ninety-six percent of the calves experienced an increase in anti-PhA1 neuraminidase antibody when sera drawn on feedyard day 28 were compared with sera drawn on the farm. These data demonstrate that the enzyme neuraminidase is produced in vivo in market stressed cattle after a natural Ph infection. Received: 23 March 1998 / Accepted: 4 May 1998