Björn A. Afzelius

The immotile-cilia syndrome. A congenital ciliary abnormality as an etiologic factor in chronic airway infections and male sterility.

We investigated six men and a woman suspected of suffering from congenital immotility of cilia. All had chronic airway infections, and the men had immotile spermatozoa. The woman and three men had Kartageners syndrome. The investigations included measurements of the mucociliary transport in the lower airways and ultrastructural studies of the sperm tails or respiratory cilia (or both). Mucociliary transport was significantly delayed. Sperm tails lacked dynein arms in five patients. Respiratory cilia from the women and two men lacked dynein arms and were irregularly oriented. The results support the hypothesis that a congenital defect in the cilia and sperm tails will cause chronic respiratory-tract infections and male sterility--the immotile-cilia syndrome. In about half these patients there will also be a situs inversus--i.e., Kartageners syndrome.

The general occurrence of mitochondrial DNA

Abstract Mitochondrial fibers with DNA-characteristics are described from a large number of cell types, representing different tissues taken from animals of eight phyla. Similar fibers are seen also in the mitochondria of the onion root tip. In an earlier study it was concluded that chick mitochondrial fibers contain DNA, and the present study shows that the DNA is an integral part of most and probably all mitochondria, although the fibers in some cases are difficult to visualize. It was demonstrated by serial sectioning of chick heart tissue that every branch of these polymorphic mitochondria contains at least one fiber. DNA fibers are often seen to be connected with the mitochondrial inner membranes. The fibers are particularly evident if the mitochondrial matrix has a relatively low density and if the fibrous material is made to clump together during the tissue preparation. The fibers of two dinoflagellate species were observed in a dispersed state after fixation conditions which produced a clumped state in all other tissues. The most prominent fibers are found in undifferentiated cells and in cells which are engaged in rapid proliferation. This fact and the finding that even the sperm cell brings its cytoplasmic store of DNA to the egg is taken as a basis for speculation on the role of these fibers. A comparison between mitochondria and bacteria with regard to their structure and function is made. Some mitochondria, apart from having fibers with DNA-characteristics, also are provided with ribosome-like granules with nucleic-acid “staining” properties.

Microtubular diversity in insect spermatozoa : results obtained with a new fixative

Abstract The architecture of the tail axoneme of spermatozoa from 49 insect species representing 20 insect orders has been examined. Whereas the microtubular walls of the nine doublet tubules and the two central singlet tubules were found to consist of a fixed number of protofilaments, the walls of the accessory tubules may consist of 13, 15, 16, 17, or 19 microtubules and have diameters from 24 to 38 nm. Cytoplasmic microtubules in the spermatid cytoplasm, outside the axoneme, may have 13, 14, or 16 protofilaments. The number of protofilaments seems constant for each class of accessory tubule and, except in Diptera, seems fixed in each insect order. Pterygote insects have 16 protofilaments and this was found in all orders except Ephemeroptera and Psocoptera with 13, Phasmida with 17, and Trichoptera with 19 protofilaments. Within Diptera, 16 protofilaments were found within the family Mycetophilidae, which for this reason can be regarded as the most primitive, extant dipteran group; the majority of dipteran flies have 13 protofilaments. Two nematoceran families, Bibionidae and Culicidae, have axonemes of a 9 + 9 + “1” type and accessory tubules with 15 protofilaments. We feel that axonemal ultrastructure is important in studies of insect phylogeny. We conclude that spermatids can effect specification of different protofilament numbers with numerical exactitude for the different types of microtubules.

Flagellar mutants in man: On the heterogeneity of the immotile-cilia syndrome

In a search for flagellar mutants in man we have examined sperm tails from men who have spermatozoa that are immotile but living. In this paper we describe 14 such cases, which belong to five distinct groups. These are: sperm axonemes lacking both dynein arms, sperm axonemes lacking the inner dynein arms, sperm axonemes lacking the outer dynein arms, sperm axonemes probably lacking the spoke heads, and sperm axonemes lacking one or both central microtubules and lacking the central sheath. Other types of flagellar defects are likely to occur, but have not been seen in this study. Men having spermatozoa of the first four of these categories have the immotile-cilia syndrome characterized by respiratory tract disease since early childhood. The three men from our fifth category did not suffer from the immotile-cilia syndrome. Their spermatozoa were characterized by the middle piece being very short and the fibrous sheath being unusually thick.

Electron microscopy on the basophilic structures of the sea urchin egg.

SummaryThe following RNA-containing components of sea urchin oocytes and eggs, some of which stratified by centrifugation, were examined in the electron microscope: the main nucleolus, the “minor nucleoli” and cytoplasmic “heavy bodies” and yolk nuclei. The inclusionfree and RNA-containing clear cytoplasm was also examined.1.The cytoplasmic RNA content was correlated with the presence of granules, somewhat angular in size and approximately 150 Å in diameter.2.In the yolk nuclei of the oocyte these granules were attached to membranes in a way characteristic of α-cytomembranes. In the clear cytoplasm they appear free.3.The “heavy bodies” were surrounded by a membrane that very closely resembled the nuclear membrane. Evidence is presented that the “heavy bodies” may be derived from the nucleus, but they are not extruded portions of the main nucleolus.

The spermatozoon of the jellyfish Nausithoë

The spermatozoon of the primitive scyphomedusa Nausithoe has a short conical head, a midpiece containing four large mitochondria, and a long tail consisting of a flagellum. It is therefore a “primitive spermatozoon” as earlier defined. Some unusual structural features have been noted. There is no evident acrosome cap, but in its place a layer containing vesicles of a complex appearance. The centrioles are removed from the nucleus and lie at the posterior end of the midpiece. The distal centriole is connected to an “anchoring fiber apparatus”, an intricate array of striated fibers which evidently anchor the flagellar base to the cell body. A proximal, 0.8 μ long, zone of the tail is peculiar in that its cell membrane carries a coat consisting of 0.2 μ long fibrils. The rest of the tail membrane has a much shorter fuzz on its outside. The ciliary filaments are double tubules, one unit of which is slightly longer than the other. In their distal tips the ciliary filaments have triangular cross sections.

On the Function of Cilia in the Female Reproductive Tract

A recently discovered syndrome is characterized by congenital immotility of the cilia. It consists of chronic infections in the respiratory system, male infertility, and, in about one-half of the cases, situs inversus. The syndrome thus includes Kartageners syndrome. The syndrome provides a unique opportunity to gain insight into the role of the cilia in the human body. Five women evidently suffering from this syndrome were examined. They had no gynecologic disorders. Three of the five women had tried to become pregnant and two have suceeded. A review of the literature indicates that men with Kartageners syndrome are usually infertile, whereas the women are not. This fact and the data presented herein constitute strong evidence that ciliary motility is not essential for female fertility. More conclusive proof could be obtained if any of the affected women would consent to ultrastructural investigation of the oviductal cilia.

Fine structure of the garfish spermatozoon

The spermatozoon of the holostean fish species gar (Lepisosteus osseus) agrees in its main features with those of primitive teleosts. Thus, it lacks an acrosome and has a short midpiece with a ring-shaped mitochondrion. There are two centrioles and both have end regions with doublets of a characteristic form. The proximal centriole is joined to a fibrous body, which sends an extension to a posterior central fossa of the nucleus. The sperm tail has two lateral sidefins which are roughly in the plane of the two central microtubules. The close correspondence between the teleost and the holostean spermatozoa is in agreement with the proposed close affinity between these two fish groups. A survey shows that other fish groups have other types of spermatozoa.

The effect of intermittent cold treatment on the adipose tissue of the cat. Apparent transformation from white to brown adipose tissue.

Young cats (Felis domestica), aged 10-13 weeks, were intermittently exposed to a temperature of -30 degrees C for two periods of 1 hr per day. Animals were sacrificed on the 7th day and adipose tissue from the perirenal, pericardial, axillary, interscapular, and subcutaneous-inguinal depots was examined by electron microscopy and analysed stereologically. All examined depots were morphologically changed after cold treatment. Adipose tissue of perirenal, pericardial, and axillary depots showed a greater decrease in lipid content than the interscapular and subcutaneous-inguinal depots, but other changes were similar. Compared to the control group, which consisted of typical white adipose tissue, the diameter of adipose cells examined after cold treatment was diminished, in extreme cases to 18 micron (from 75 micron in the control group). The number of capillaries per cell was doubled (as evaluated on semithin sections). The most dramatic changes were observed in the mitochondria. Their volume increased to 0.48 micron 3 (from 0.13 micron 3 in the control), and the surface density of mitochondrial cristae per mitochondrial volume increased to 50 micron 2/micron 3 (from 32 in the control). Pleomorphism in mitochondrial size and inner structure and the presence of intramitochondrial electron-dense bodies and crystalline structures led us to conclude that the cold stress induced an increase in the absolute number of mitochondria in the adipose cells. The adipose tissue after cold treatment thus morphologically resembled the brown adipose tissue of cold-acclimated rodents. This implies that the adipose tissue of young cats can change its morphology and function, depending on the requirements of the organism.

Cilia and flagella that do not conform to the 9 + 2 pattern: I. Aberrant members within normal populations

Descriptions are given of abnormal cilia and flagella with (a) supernumerary peripheral filaments, (b) supernumerary central filaments, (c) reduced peripheral filaments, or (d) lacking central filaments. With a proposed coding system the number of filaments at various levels from the ciliary axis is registered. The following patterns are reported: 1 + 9 + 2, 2 + 9 + 2, > 2 + 9 + 2, 5 + 8 + 2, 6 + 2, 7 + 0, 9 + 4, and 10 + 4. The descriptions are from cross sections and refer to limited segments of the cilia. It is thus not known whether the centriole is changed or normal. The possibility that only a distal part of the cilium is modified cannot be excluded. The cylinder of peripheral filaments is filled by 9 (rarely 8 or 10) filaments. At higher numbers of supernumerary filaments a new shell of filaments is present; when the number of filaments is below 8 the cylinder has a slot. The optimal number, 9, might be determined by the morphology of the peripheral filament. Two additional observations are: local fragmentation of the ciliary membrane, and the possibility to measure, on a favorable material, the circular ciliary cross section.