A Hyper-Parasite of Iodamoeba buetschlii from the Rhesus Monkey, Macaca mulatta, and the Domestic Pig

SYNOPSIS. So called "inclusion" bodies in the cytoplasm of Iodamorba biretschlii cysts from rhesus monkeys ( Mocaca mulatta ) and domestic pips appeared to be hyper-parasites of unknown taxonomic position (posubly a protozoon or a fungus), They had a dot-like Feulgen-positive nucleus, cytoplasmic alkaline phosphatase, periodic acid Schiff -positive material, and proteins reacting to the bromophenol blue test. Their nuclei appeared to divide by budding and ultimately to produce six to eight minute, round or oval spore-like bodies. The Iodamoeba cysts mntaining these bodies had highly vacuolated cytoplasm, suggesting that the hyper-parasites had a degenerating effect on their host.     

Late Cambrian hard substrate communities from Montana/Wyoming: the oldest known hardground encrusters

Hardground surfaces from the Late Cambrian Snowy Range Formation in Montana/Wyoming are the oldest known non-reefal hard substrates exhibiting encrusting fossils. These surfaces range in age from Early Franconian to early Trempealeauan. Hardgrounds were developed on slightly hummocky to planar, truncated surfaces of glauconite-rich, carbonate, flat pebble conglomerates, which were deposited during episodes of storm scouring in shallow subtidal environments of the Montana/Wyoming shelf. Snowy Range hardgrounds are encrusted by a low diversity assemblage of fossils dominated by simple discoidal holdfasts of pelmatozoans, probably crinoids, and including small conical spongiomorph algae? and probable stromatolites. Macroborings (e.g. Trypanites) are notably absent from all hardground surfaces, although sharp-walled, vertical, cylindrical holes (borings?) occur in micrite clasts imbedded in certain flat pebble conglomerates. No evidence of faunal succession or microecologic partitioning of irregular surfaces was observed on these Cambrian hardgrounds.     

Farbmuster auf jurassischen Belemniten-Rostren

Colour patterns have been observed in belemnites of the genus Megateuthis from the middle Jurassic of North and South Germany. They are present only in adult specimens, appearing first on the dorsal and then on the ventral side, and, finally, on the flanks. This suggests that the rostrum at this stage was covered only by a thin (translucent) layer of soft tissue. More probably, the rostrum was temporarily uncovered, as indicated by the presence of borings of fungi or algae on several rostra. The regular distribution of these borings suggests pre-mortem infestation of the belemnites. Fossil bacteria have also been found within the individual colour patterns.     

A New Ichnospecies of Gastrochaenolites Leymerie from the Pleistocene Port Morant Formation of Southeast Jamaica and the Taphonomy of Calcareous Linings in Clavate Borings

The ichnospecies Gastrochaenolites pickerilli isp. nov. is based on ten borings found in a shell of the gastropod Strombus gigas Linné from the Pleistocene (Sangamonian) Port Morant Formation of southeast Jamaica. These borings bear morphological similarities to Gastrochaenolites torpedo Kelly and Bromley but differ from all other Gastrochaenolites ispp. in having prominent and numerous calcareous meniscate structures arrayed adjacent to one side of the boring. These menisci are concave towards the center of the boring and are the remnants of calcareous tubes that lined earlier boreholes, that the boring bivalve treated as part of the lithified substrate when relocating. They are thus evidence of the former positions of borings that, unusually, were breached as the bivalve migrated sideways. Although this was a common behavior for Gastrochaenolites-producing bivalves within this substrate, the reason for it occurring is uncertain.     

Functional morphology and taxonomy of branch dimorphism in the Paleozoic bryozoan genus Rhabdomeson

Silicified maria of the widespread cylindrical genus Rhabdomeson have been discovered that bear conical branches traditionally assignable to Coeloconus . Other, conical stems gave rise to cylindrical branches. That the dimorphic branches are not encrustations is shown by the absence of overgrowths and the regular alignment of apertures between parent stem and branch. A similar relationship is true of the type species of Coeloconus , which is synonymized with Rhabdomeson . Both conical and cylindrical branches were broken but survived to resume growth; this is shown by basal healing patterns and growth reversals. Colony fragmentation has been described in certain Cenozoic and modern bryozoans as a mode of increase, and is inferred to have been important in Rhabdomeson . The presence of fragmentation in taxonomically and stratigraphically widely separated bryozoans suggests that this mode of increase may be more important than realized.     

Cohesive properties of mammalian epididymal spermatozoa

Changing spermatozoan associations were observed in the epididymides of several mammals. These associations ranged from closely interwoven cylindrical bodies, found in the proximal part of the epididymis, to disorganized masses of spermatozoa, found in the distal part of the duct. It is suggested that changes in the cohesive properties of epididymal spermatozoa resulted in the formation and fragmentation of cylindrical bodies. These bodies, differeing in pattern and complexity according to the species, were found in all investigated mammals, including man. Cohesiveness appeared first in the upper part of the epididymidis, where it was confined to the spermatozoan tails. In general, there was a diminution of cohesive forces as the spermatozoa passed down the epididymal duct; consequently, the cylindrical bodies turned into disorganized masses of spermatozoa. There are indications that changes in the cohesive properties of spermatozoa may represent one aspect of spermatozoan maturation.     

Primary rotational stability of cylindrical and conical revision hip stems as a function of femoral bone defects: an in vitro comparison

Bone stock losses in cementless femoral stem revisions compromise a stable fixation. The surgeon has to rely on his wealth of experience in deciding which stem shape to use. The aim of our study was to compare the primary rotational stability of cylindrical and conical revision hip stems subjected to femoral defects. Four current prostheses (two cylindrical, two conical) were implanted into four synthetic femora. Micro-motion was measured under torque application and femoral neck osteotomy and segmental AAOS Type I and III defects were simulated. The relative movements of all prostheses were significantly influenced by the extent of bone loss (p<0.01). Major differences were seen in fixation behavior (p<0.01). The main fixation area of conical stems is within the distal femoral isthmus, whereas cylindrical implants are dependent on proximal bone stock. In our study, cylindrical stems are advantageous for minor defects because they provide a proximal fixation. In cases of extensive substance loss, the conical implants showed lesser relative movements. These findings should be taken into account for clinical decisions.     

Morphological and ultrastructural features in selected species of Licea (Myxomycetes)

Ultrastructural studies of selected species of Licea were made in order to elucidate relationships among species. Based on structural studies, species may be grouped as representing different stages of morphological complexity. The majority of species possess protoplasmodia and form sporangia. The two plasmodiocarpous species L. retiformis and L. variabilis possess more highly differentiated plasmodia and are an anomaly among Licea species. Processes along the margin of peridial lobes in several species of the genus are probably homologous with the capillitium in Listerella . The latter genus is morphologically and structurally very similar to species of the Licea pusilla group, but its plasmodium is still unknown. The sole species of Listerella agrees with Licea operculata in the structure of spore ornamentation, the processes consisting of densely packed granules of high electron density. This structure is quite different from that of L. pusilla and L. minima , where the processes have an internal structure of alternating layers different in electron transparency. Presence of spore-like bodies, different in size and ornamentation from normal spores, have been demonstrated in the border region between stalk and sporangium in L. operculata . This is a feature previously supposed to be restricted to Arcyria and related genera. Using X-ray analysis, calcium has been found in the peridium of several species of Licea . Since environmental factors may influence the presence or absence of calcium, caution should be taken in interpreting differences taxonomically. The similarity in elemental composition between the spores and sporangial lid in L. operculata is interesting, considering the fact that the sporangial lid of Trichia crateriformb has been demonstrated to be composed of spore-like structures.     

Computational fluid dynamics in the oral cavity of ram suspension-feeding fishes

We have modeled steady, three-dimensional flow with a no-slip boundary condition in cylindrical and conical oral cavities possessing vertical or slanted branchial slits. These numerical simulations illustrate the transport of food particles toward the esophagus, as well as the velocity profiles of water exiting the oral cavity via the branchial slits. The maximum and average velocities are highest for flow exiting the most posterior branchial slit. The highest volume flow rates also occur in the most posterior slit for the cylindrical simulations, but occur in the most anterior slit for the conical simulations. Along the midline, there is a pronounced bilaterally symmetrical vortex in the posterodorsal region of the cylindrical and conical oral cavities and a second bilaterally symmetrical vortex in the posteroventral region of the cylinder. Particles entrained in the vortices will recirculate in the posterior oral cavity, increasing the probability of encounter with sticky, mucus-covered surfaces such as the oral roof, gill arches, or gill rakers. The posterodorsal vortex could serve to concentrate particles near the entrances of the epibranchial organs. The ventral vortex could be involved in sequestering dense inorganic particles that sink toward the floor of the oral cavity. All vortices are absent in the conical simulation with vertical branchial slits, indicating that the slanted branchial slits between the gill arches are responsible for the formation of the vortex in the conical oral cavity. Experiments using in vivo flow visualization techniques are needed to determine whether ram suspension feeders, pump suspension feeders, and non-suspension-feeding fishes possess vortices in the posterior oral cavity that contribute to particle transport, food particle encounter with sticky surfaces, and inorganic particle rejection.     

Host‐specific acrothoracid barnacles on Middle Devonian platyceratid gastropods

Borings, attributed to acrothoracic barnacles, occur on the platyceratid gastropod Naticonema lineatum (Conrad) from the Middle Devonian Hamilton Group of western New York and rarely in specimens as old as the Early Devonian. These latter are the oldest known acrothoracid borings are in the fossil record. The borings are consistently developed as laterally compressed, inequilateral pouches exclusively on these gastropods, commonly as dense infestations.

Naticonema shells yielding borings typically occur associated with partially articulated qrinoid remains, and they are sometimes found attached to crinoids in a manner similar to coprophagous Platyceras. In addition to barnacle borings, Naticonema shells often bear thin encrustations of bryozoans which are usually perforated by these borings but sometimes also overgrow them. Barnacles bored live hosts; gastropods prevented shell penetration by producing cyst‐like secondary secretions of calcite beneath acrothoracid boreholes.

The relative antiquity of these borings and their association with coprophagous platyceratids makes their discovery particularly significant in revealing aspects of the early ecology of barnacles. Attachment to the host commensal gastropods was one of the first successful life modes of these crustaceans prior to their later diversification to other habitats. Mississippian and Pennsylvanian occurrences of similarly bored gastropods demonstrate continuity of the barnacle‐gastropod‐crinoid ecological association from the Middle to Late Paleozoic.     

Comparison of the primary stabilities of conical and cylindrical endosseous dental implants: an in-vitro study

The aim of this study is to determine the differences in primary stability between conical and cylindrical dental implants. The insertion and removal torques were the parameters used to measure the primary stability of the implants. Ten conical and cylindrical dental implants were positioned in polyurethane foam blocks to simulate bone density classes D1, D2, D3 and D4. The insertion and removal torques were quantified using a digital torque gauge. The maximum insertion torque and the maximum removal torque measured for the D1 and D4 synthetic bone were significantly higher for the conical implants than the cylindrical implants. In this in-vitro model, conical implants show significantly higher primary stability than cylindrical implants for the D1 and D4 synthetic bone classes.     

Taphonomy of Logs Bored with Teredolites longissimus Kelly and Bromley in the Danian (Lower Paleocene) of West Greenland

The boring Teredolites longissimus Kelly and Bromley is recorded infesting silicified logs in the Fossil Wood Member, Kangilia Formation (Lower Danian, Paleocene) of West Greenland. There are two morphologies of T. longissimus, probably representing two different episodes of invasion of the wood. The initial borings of Morphology 1 are large, deformed to an elliptical section, and confined to a direction of boring parallel to sub-parallel to the wood grain. Morphology 2 borings are less common, narrower and shorter, sinuous, markedly crosscut the grain of the wood and, where preserved intact, retain their circular cross-section. They were a later infestation than Morphology 1. Following the infestation by Morphology 1, the logs were deformed, probably by weight of overburden, and then reworked, when some of them were infested by Morphology 2 producers. Final burial was followed by brittle collapse of some Morphology 2 borings and lithification before further deformation could occur. The occurrence of T. longissimus in deeper water deposits close to a land mass with a steep slope indicates that transport in the marine realm was minimal before waterlogging.     

Nautiloid debris oriented by long-shore currents along a late Ordovician-early Silurian rocky shore

Siphuncular fragments from arminocerid cephalopods are abundant along 350 m of a well defined rocky shore of late Ordovician or early Silurian age exposed near Churchill in northeastern Manitoba, Canada. The paleoshore is composed of the Precambrian Churchill Quartzite, which is dramatically abutted by carbonate strata gently dipping north beneath Hudson Bay. At one end of the exposure, a former sea stack or sea arch extends prominently outward for 15 m perpendicular to the otherwise linear paleoshore. Probably it acted as a natural groin with some influence on local currents and waves. The orientations of 189 siphuncular fragments were recorded and found to be dominantly perpendicular to the trend of the ancient shore. They are far more cylindrical in shape than conical, and are interpreted to have been rolled to their final resting place pushed by long-shore currents. Concentration of nearly 80% of the fragments towards one end of the shore is consistent with transport by long-shore currents. Ripple marks preserved at a different stratigraphic level form a 45-degree angle to the trend of the paleoshore, providing additional evidence that wave trains must have set up long-shore currents from time to time.     

Sperm morphology in four species of African platypleurine cicadas (Hemiptera: Cicadomorpha: Cicadidae)

Mature spermatozoa from four species of platypleurine cicadas (Albanycada albigera, Azanicada zuluensis, Platypleura capensis and P. hirtipennis) were examined by light and electron microscopy. The filiform sperm have a similar ultrastructure in all species but notable variations were found in sperm dimensions. All species produce more than one discrete length of nucleated, motile sperm, a form of polymorphism termed polymegaly. Polymegaly is expressed in two ways: sperm have bi- or trimodal head and tail lengths. The anterior parts of sperm heads are embedded in an elongate homogenous matrix forming a spermatodesm. The conical acrosome is deeply invaginated posteriorly, and sits on top of the nucleus. The acrosomal contents are differentiated internally with an electron-lucent central medulla and a denser cortex. The homogenously electron-dense nucleus is pointed anteriorly and is generally cylindrical, although posteriorly there is a lateral invagination that extends part-way along the nucleus. This invagination houses fine granular material of the centriolar adjunct. Vesicle-like elements that are associated with both the posterior nucleus and the centriolar adjunct are also found within the invagination. Immediately posterior of and adjoining the centriolar adjunct is a pair of mitochondrial derivatives that are elongated and extend for almost the entire length of the tail. The absence of accessory bodies in cicada sperm suggests that within the Cicadomorpha, the families Cicadidae and Cercopidae are closely affiliated.     

Pulmonary epithelial stem cells

Classically, the stem/progenitor cells of the pulmonary epithelium are considered to be the basal and mucous cells of the proximal airways, Clara cells in the bronchioles and type II pneumocytes in the alveoli. Recent data suggest that there is a variant of Clara cells, lying in pulmonary neuroendocrine bodies, that meets several stem cell criteria and that type II pneumocytes exist in at least two populations, one of which is more resistant to injury. However, a complete revision of our understanding of pulmonary stem cell biology is underway as a result of the discovery of pulmonary epithelium derived from blood-borne cells. In addition, the existence in the lung of a 'universal' pluripotent cell has long been speculated upon and now some initial evidence has emerged with the identification of a spore-like cell that can differentiate in vitro to bronchiolar tissue.     

The shape of the thorax based on data of fluorographic studies]

Five thoracic types were distinguished on the basis of 3 transverse sizes between the 4th, 7th, and 10th ribs, detected on the thoracic fluorograms of 1116 men and 1460 women: cylindrical, narrow conical, conical, wide conical, and egg-shaped. A subtype of a cylindrical thorax--cylindrical with a waist--was distinguished in women. In men conical chests occurred in 48.9% of cases, wide conical in 24%, whereas in women narrow conical chests occurred in 41.8% and cylindrical in 27.5% of cases. The examinees were grouped in accordance with the thoracic shape and their physical parameters and the parameters of the chests were compared. The chest proportions represent the most comprehensive characterization of the skeletal index: the ratio between the transverse size between the 7th ribs and the vertical size in per cent. The skeletal index directly correlates with body mass, thoracic circumference, transverse and longitudinal sizes of the heart and is in inverse correlation with body length, angle of inclination of the 8th rib and angle of inclination of the heart axis to the horizontal line.     

Use of conical wire arrays for modeling three-dimensional MHD implosion effects

Results are presented from experimental studies and numerical simulations of three-dimensional dynamics of the plasma produced in the Angara-5-1 facility by the electrical implosion of conical wire arrays at currents of up to 3 MA. The arrays were made of 6-to 8-μm-diameter tungsten wires, the inclination angle of the generatrix with respect to the axis being from 15° to 42°. The results of two-dimensional MHD simulations are compared with experimental data. The formation dynamics of the plasma precursor is found to be different for cylindrical and conical arrays. As the cone angle increases, the duration of the X-ray pulse increases, while the height of the pinch radiating zone decreases.     

Spatiotemporal behavior of X-ray emission above 20 keV from a Z-pinch produced by wire-array implosion

Results are presented from experimental studies of hard X-ray (HXR) emission in the photon energy range above 20 keV from dense radiating Z-pinch plasmas. The work is aimed at revealing the nature of fast-electron (electron beam) generation during the implosion of cylindrical and conical wire arrays in the Angara-5-1 facility at currents of up to 3 MA. It is found that the plasma implosion zippering caused by the inclination of wires affects the parameters of the HXR pulse emitted during the implosion of a conical array. It is shown that HXR emission correlates well with the decay of the plasma column near the cathode in the stagnation phase. HXR images of the pinch are produced by the bremsstrahlung of fast electrons generated during plasma column decay and interacting with plasma ions and the anode target. It is found that the use of conical arrays makes it possible to control the direction of plasma implosion zippering and the spatiotemporal and energy parameters of the pinch X-ray emission, in particular the X-ray yield. For wire array with diameters of 12 mm and linear masses of 200–400 μg/cm, the current of the fast electron beam is 20 kA and its energy is 60 J, which is about 1/500 of the energy of the main soft X-ray pulse.     

Stegmata in Orchidales: character state distribution and polarity

The- distribution of stegmata in Orchidales is given for 130 species representing 105 genera. The stegmata occur in leaves and stems as longitudinal files of silica cells. lining fibre bundles or vascular bundle sheaths. The silica bodies contained in orchid stegmata arc of two major kinds, spherical and conical. The species investigated are characterized either by a single kind of silica body or by lack of silica cells. Absence of stegmata and presence of stegmata with conical bodies are the two most common character states in the order. The stegmata containing spherical bodies characterize Vandeae and Eriinae, Podochilinae, and Dendrobiinae within Epidendreae
Comparison of character slates of the various groups within the family is used for a discussion of evolutionary polarity. The function of silica accumulation is reconsidered in the light of the epiphytic life-form of many of the investigated orchids.     

The ultrastructure of a new species of Chlamydia--Chlamydia pneumoniae]

The dynamic study of a new Chlamydia species, C. pneumoniae (strain TWAR, isolate TW-480), inoculated into the monolayer culture of cells L-929 was made 24, 48, 72 and 96 hours after inoculation. When compared with C. trachomatis and C. psittaci, C. pneumoniae were found to stand between these two species with respect to the morphology of their intracytoplasmic microcolonies (inclusions): they were round, almost bubble-like, but more densely packed with chlamydiae, surrounded by an undulate membrane, preserving its integrity until the late stages of their development cycle. In cells L-929 C. pneumoniae had a typical development cycle accompanied by the formation of vegetative and spore-like cells, reticular and elementary bodies, as well as intermediate cells, though this process was slower than in C. trachomatis and C. psittaci. Besides normal elementary bodies, many altered ones were formed in the process of the development of C. pneumoniae in cells L-929. Most of these alterations were similar to the process of bacterial L-transformation and could be regarded as the manifestation of chlamydial pathology related to the adaptation to new host cells.