ALBERT

Notes: Abstract The 6-km-thick Karmutsen metabasites, exposed over much of Vancouver Island, were thermally metamorphosed by intrusions of Jurassic granodiorite and granite. Observations of about 800 thin sections from the Campbell River and Buttle Lake area show that the metabasites provide a complete succession of mineral assemblages ranging from the zeolite to pyroxene hornfels facies around the intrusion. The most important observations are as follows. (1) The compositional change of Ca-amphiboles with increasing metamorphic grade is not straightforward. The tremolite component decreases from the prehnite–actinolite facies to the greenschist facies with a compensating tschermak component increase, but the tendency is not clear thereafter. Instead, the edenite component increases from the amphibolite facies to the pyroxene hornfels facies. (2) The most pargasitic Ca-amphibole occurs in high-Fe2+/Mg metabasite from the greenschist/amphibolite transition zone. (3) The reasons for such irregular compositional trends, even in the rather uniform MORB-like composition of the Karmutsen metabasites, are non-ideal solid solutions of Ca-amphibole at low temperature and the effective control by bulk rock composition in the amphibolite facies. (4) The data from this study support, but do not prove, a transition loop for the actinolite–hornblende compositional gap rather than a solvus. If the gap is a solvus, its shape is asymmetric, and is highly dependent on the other compositional parameters such as Fe3+/Al and Fe2+/Mg. (5) The XNaA/XA±XAb) ratios between Ca-amphibole and plagioclase are most useful as an indicator of metamorphic grade even within the amphibolite facies, and these change systematically from 0.2 to 0.5 from the greenschist to pyroxene hornfels facies. (6) The compositional trend of Ca-amphibole from the Karmutsen metabasites indicates a typical low-P/T metamorphic facies series on a Rbk–Gln–Tr–Ts diagram.

Notes: Abstract The central sector of Mühlig-Hofmannfjellet (3°E/71°S) in western Dronning Maud Land (East Antarctic shield) is dominated by large intrusive bodies of predominantly orthopyroxene-bearing quartz syenites (charnockites). Metasedimentary rocks are rare; however, two distinct areas with banded gneiss–marble–quartzite sequences of sedimentary origin were found during the Norwegian Antarctic Research Expedition NARE 1989/90. Cordierite-bearing metapelitic gneisses from two different localities contain the characteristic mineral assemblage: cordierite + garnet + biotite + K-feldspar + plagioclase + quartz ± sillimanite ± spinel. Thermobarometry indicates equilibration conditions of about 650°C and 4 kbar. Associated orthopyroxene–garnet granulites, on the other hand, revealed pressures of about 8 kbar and temperatures of 750°C. The earlier granulite facies metamorphism is not well preserved in the cordierite gneisses as a result of excess K-feldspar combined with interaction with an H2O-rich fluid phase, probably released by the cooling intrusives. These two features allowed the original high-grade K-feldspar + garnet assemblages to recrystallize as cordierite–biotite–sillimanite gneisses, completely re-equilibrating them. Phase relationships indicate that the younger metamorphic event occurred in the presence of a fluid phase that varied in composition between the lithologies.

Notes: Quantitative Methods in Petrology. Edited by T. M. Gordon.

Notes: Abstract Archaean and Proterozoic granulite facies complexes of Inner Mongolia differ in lithological association, tectonic style, mineral assemblage and metamorphic P–T path. A nearly isobaric cooling path for Archaean high-grade metamorphic rocks is suggested by reaction textures and geothermobarometry. Early Proterozoic metamorphic rocks show nearly isothermal decompression. Archaean metamorphism may have been caused by magmatic accretion, whereas early Proterozoic metamorphism suggests a major continental thickening event followed by exhumation.

Notes: Abstract Two blueschist belts in the North Qilian Mountains occur in Middle Cambrian and Lower Ordovician strata and strike N30–35°W for about 500 km along the Caledonian fold belt on the south-west margin of the Sino-Korean plate. The styles of metamorphism and deformation are quite different in the two belts. The Middle Cambrian to Ordovician rocks in the high-grade belt are mainly blueschists and C-type eclogites in which six phases of lower and upper crustal deformation have been recognized. The rocks contain glaucophane, phengite, epidote, clinozoisite, chlorite, garnet, stilpnomelane, piedmontite, albite, titanite and quartz. The estimated P–T conditions of eclogites are 340 ± 10°C, 8 ± 1 kbar and, of blueschist, 〉380°C, 6–7 kbar. The Ordovician rocks in the low-grade belt are characterized by ductile to brittle deformation in the middle to upper crust. The low-grade blueschists contain glaucophane, lawsonite, pumpellyite, aragonite, albite and chlorite. The estimated P–T conditions are 150–250°C and 4–7 kbar.K–Ar and 39Ar/40Ar geochronology on glaucophane and phengite from the high-grade blueschist belt suggest two stages of metamorphism at 460–440 and 400–380 Ma, which may represent the times of subduction and orogeny. The subduction metamorphism of the northern low-grade blueschist belt took place approximately at the end of the Ordovician.

Notes: Abstract Regional metamorphic rocks that form Late Palaeozoic subduction complexes in central Queensland, Australia, are products of two metamorphic episodes. Synaccretion metamorphism (M1) gave rise to prehnite-pumpellyite and greenschist facies rocks, whereas a subsequent episode (M2) at about 250 Ma formed upper greenschist to upper amphibolite facies rocks of both intermediate- and low-pressure type, probably in a compressive arc or back-arc setting. A similar pattern can be recognized for 1000 km along the New England Fold Belt, although at several localities, where higher grade rocks are exposed, metamorphism was essentially continuous over the M1-M2 interval, with a rapid rise in geothermal gradient at the end of accretion. Where out-stepping of tectonic elements has occurred at long-lived convergent margins elsewhere, similar overprinting of high- by lower-pressure facies series is anticipated, complicating the tectonic interpretation of metamorphism. The discrete character of metamorphic events may be blurred where conditions giving rise to a major episode of accretion and out-stepping are followed by the subduction of a major heat source.

Notes: Abstract Deformed quartz veins in garnet-zone schist adjacent to the active Alpine Fault, New Zealand, have fluid inclusions trapped along quartz grain boundaries. Textures suggest that the inclusions formed in their present shapes during annealing of the deformed veins. Many of the inclusions are empty, but some contain carbon dioxide with densities that range from 0.16 to 0.80 g cm−3. No water, nitrogen or methane was detected. The inclusions are considerably more CO2-rich than either the primary metamorphic fluid (〈5% CO2) or fluids trapped in fracture-related situations in the same, or related, rocks (〈50% CO2). Enrichment of CO2 is inferred to have resulted from selective migration (wicking) of saline water from the inclusions along water-wet grain boundaries after cooling-induced immiscibility of a water-CO2 mixture. Inclusion volumes changed after loss of water. Non-wetting CO2 remained trapped in the inclusions until further percolation progressively removed CO2 in solution. This mechanism of fluid migration dominated in ductile quartz-rich rocks near, but below, the brittle-ductile transition. At deeper levels, hydraulic fracturing is also an important mechanism for fluid migration, whereas at shallower levels advection through open fractures dominates the fluid flow regime.

Notes: Abstract The North Shore Volcanic Group in northern Minnesota is part of the Middle Proterozoic Keweenawan sequence, one of the largest plateau lava provinces in the world. The primary geochemistry of the basalts suggests that volcanism occurred in an intracontinental rift environment. The subaerial lava flows, mainly amygdaloidal olivine tholeiites and tholeiites, have undergone low-grade metamorphism from zeolite to lower greenschist facies. On the basis of alteration phases replacing the primary magmatic minerals, infilling amygdales and veins, and replacing secondary minerals, the following zones have been distinguished: (1) thomsonite-scolecite-smectite, (2) heulandite-stilbite-smectite, (3) laumontitechlorite-albite, (4) laumontite-chlorite-albite ± prehnite ± pumpellyite and (5) epidote-chlorite-albite ± actinolite zone.In addition to the overall zonation based on mineral parageneses, zonations in the composition of the Ab content of the newly formed albite replacing primary Ca-rich plagioclase and of the newly formed mafic phyllosilicates are observed within the sequence and within single flows. Mafic phyllosilicates in the upper part of the sequence (mainly smectites and mixed-layer smectite/chlorites) display high Si and Ca + Na + K contents, whereas in the lower part of the sequence the amounts of Si and Ca + Na + K are markedly lower (mainly chlorites and mixed-layer chlorite/smectites). Similar zonations are observed within the individual flows. The albite content of the newly formed plagioclase is highest, and the Si and Ca + Na + K content of the phyllosilicates lowest in the amygdaloidal flow top while the opposite is true for the massive flow interior.The above features suggest that the overall pattern is one of burial-type metamorphism associated with extension in the rift setting. In detail, the mineral assemblages are controlled not only by the stratigraphic position but also by the flow morphology controlling permeability whose effect on the assemblages is most pronounced in the stratigraphically upper parts. This suggests that at the first stages of alteration (lowest grade) the patterns of fluid flow were important effects in controlling the assemblages. At greater burial depth, assemblages are more homogeneous, perhaps representative of a more even and pervasive flow pattern.Using the observed assemblages at face value to define grade and/or facies, different conditions would be assigned within the different morphological flow portions. Thus at low-grade metamorphic conditions it is essential to integrate assemblages from different morphological flow portions in order to define satisfactorily the overall metamorphic conditions.

Notes: Abstract Three types of mineral associations are described from calc-silicate granulites from the Eastern Ghats, India, where geothermobarometry in associated rocks suggests extremely high P–T conditions of metamorphism (c. 9 ± 1 kbar, 950° C). These mineral associations are: (i) calcite + quartz + scapolite + plagioclase, (ii) calcite + scapolite + wollastonite + porphyroblastic garnet + coronal garnet and (iii) calcite + quartz + wollastonite + scapolite + porphyroblastic garnet + coronal garnet, all coexisting with K-feldspar, titanite and clinopyroxene. The first two associations evolved through nearly isobaric cooling retrograde paths, whereas the third evolved through a nearly isothermal decompression path followed by an isobaric cooling retrograde path. Textural and compositional characteristics suggest the following mineral reactions in the calc-silicate granulites: calcite + quartz = wollastonite + CO2, calcite + plagioclase = scapolite, calcite + scapolite + wollastonite = porphyroblastic garnet ± quartz + CO2, CaTs + wollastonite = coronal garnet (association ii) and wollastonite + scapolite = coronal garnet (association iii) + quartz + CO2. Andradite content in garnet was buffered by the redox equilibria wollastonite + hedenbergite + O2= andradite + quartz (association iii) and wollastonite + andradite + CaTs + scapolite = hedenbergite + calcite + grossular + O2 (association ii). The contrasting mineral parageneses have been ascribed to interplay of variables such as XCO2, fO2, fHCl in the fluid, bulk Na content and the nature of the retrograde P–T–XCO2 paths through which the rocks evolved.

Notes: Abstract The D'Entrecasteaux Islands of eastern Papua New Guinea consist of a number of active metamorphic core complexes formed under an extensional tectonic setting related to sea-floor spreading in the west Woodlark Basin. The complexes are defined by mountainous domes (〉2500 m high) of fault-bounded, high-grade metamorphic rocks (including eclogite facies) intruded by 2–4-Ma granodiorite plutons. Garnet–clinopyroxene exchange thermometers indicate that the temperature of equilibration of the eclogites was 730–900° C. The jadeite component of omphacite indicates minimum pressure of 21 kbar, suggesting depths of 〉70 km.The metamorphic rocks have undergone widespread retrogression to amphibolite facies. Retrogression of the metamorphic basement is associated with shearing and formation of the metamorphic core complexes. P–T conditions in the early stages of shear zone activity, determined using the garnet–biotite exchange thermometer and the GASP and GRIPS barometers, were 570–730° C and 7–11 kbar. A second phase of re-equilibration at much lower pressures appears to be related to the widespread intrusion of granodiorite plutons. One re-equilibrated gneiss indicated maximum temperature of 730° C at estimated pressures of approximately 4 kbar. This late, high-temperature metamorphism is also indicated by reactions involving the production of hercynite and corundum in aluminous gneisses and formation of sillimanite at the expense of kyanite.Two major episodes of granodiorite intrusion occurred during uplift and exhumation of the core complexes. Both closely coincide spatially with high-temperature metamorphic rocks, the onset of deformation in extensional shear zones and subsequent uplift of the metamorphic basement. These observations indicate a fundamental link between uplift and granodiorite intrusion during continental extension and the formation of the D'Entrecasteaux Islands metamorphic core complexes.

Notes: Abstract Fluids with compositions in the system CO2-H2O-NaCl were trapped in quartz veins enclosed in low-grade metamorphic rocks (chlorite zone) on the southern flank of the Canigó Massif, eastern Pyrenees. The veins, which also contain arsenopyrite crystals, were formed contemporaneously with the main Hercynian foliation and metamorphism. Volumetric properties of the fluid and the results of arsenopyrite geothermometry suggest P-T trapping conditions of 4.6–6 kbar and 450–530° C. This implies that an episode of metamorphism with an average geothermal gradient of 25° C km−1 occurred during the main deformation event. This episode preceded the low-P/high-T metamorphism described around domes and to date considered as characteristic of the Hercynian orogeny in the Pyrenees.

Notes: Abstract In the Twin Lakes area, central Sierra Nevada, California, most contact metamorphosed marbles contain calcite + dolomite + forsterite ± diopside ± phlogopite ± tremolite, and most calc-silicate hornfelses contain calcite + diopside + wollastonite + quartz ± anorthite ± K-feldspar ± grossular ± titanite. Mineral-fluid equilibria involving calcite + dolomite + tremolite + diopside + forsterite in two marble samples and wollastonite + anorthite + quartz + grossular in three hornfels samples record P± 3 kbar and T± 630° C. Various isobaric univariant assemblages record CO2-H2O fluid compositions of χCO2= 0.61–0.74 in the marbles and χCO2= 0.11 in the hornfelses. Assuming a siliceous dolomitic limestone protolith consisting of dolomite + quartz ° Calcite ± K-feldspar ± muscovite ± rutile, all plausible prograde reaction pathways were deduced for marble and hornfels on isobaric T-XCO2 diagrams in the model system K2O-CaO-MgO-Al2O3-SiO2-H2O-CO2. Progress of the prograde reactions was estimated from measured modes and mass-balance calculations. Time-integrated fluxes of reactive fluid which infiltrated samples were computed for a temperature gradient of 150 °C/km along the fluid flow path, calculated fluid compositions, and estimated reaction progress using the mass-continuity equation. Marbles and hornfelses record values in the range 0.1–3.6 × 104 cm3/cm2 and 4.8–12.9 × 104 cm3/cm2, respectively. For an estimated duration of metamorphism of 105 years, average in situ metamorphic rock permeabilities, calculated from Darcy's Law, are 0.1–8 × 10−6 D in the marbles and 10–27 × 10−6 D in the hornfelses. Reactive metamorphic fluids flowed up-temperature, and were preferentially channellized in hornfelses relative to the marbles. These results appear to give a general characterization of hydrothermal activity during contact metamorphism of small pendants and screens (dimensions ± 1 km or less) associated with emplacement of the Sierra Nevada batholith.

Notes: Contact Metamorphism. Edited by D. M. Kerrick.Oxide Minerals: Petrologic and Magnetic Significance. Edited by D. H. Lindsley.Geology and Tectonics of the Karakoram Mountains. By M. P. Searle.

Notes: Abstract The St Malo region in north-west France contains migmatites and anatectic granites derived by partial melting of metasedimentary protoliths during Cadomian orogenesis at c. 540 Ma. Previously reported Rb–Sr model ages for muscovite and biotite range from c. 550 to c. 300 Ma, and suggest variable resetting of mineral isotopic systems. These rocks display microscopic evidence for variably intense Cadomian intracrystalline plastic strain but record no obvious evidence of penetrative Palaeozoic regional deformation. 40Ar/39Ar mineral ages have been determined to evaluate better the extent, timing and significance of Palaeozoic overprinting.Eleven muscovite concentrates and one whole-rock phyllite have been prepared from various units exposed in the St Malo and adjacent Mancellian regions. In the Mancellian region, muscovite from two facies of the Bonnemain Granite Complex record 40Ar/39Ar plateau ages of c. 527 and 521 Ma. An internally discordant 40Ar/39Ar release spectrum characterizes muscovite from protomylonitic granite within the Cadomian Alexain-Deux Evailles-Izé Granite Complex, and probably records the effects of Variscan displacement along the North Armorican Shear Zone. Muscovite concentrates from anatectic granite and from Cadomian mylonites along ductile shear zones within the north-western sector of the St Malo region exhibit internally discordant 40Ar/39Ar release spectra which suggest variable and partial late Palaeozoic rejuvenation. By contrast, muscovite concentrates from samples of variably mylonitic Brioverian metasedimentary rocks exposed within the south-eastern sector of the St Malo region display internally concordant apparent age spectra which define plateaux of 326–320 Ma. A whole-rock phyllite sample from Brioverian metasedimentary rocks exposed along the eastern boundary of the St Malo region displays an internally discordant argon release pattern which is interpreted to reflect the effects of a partial late Palaeozoic thermal overprint. Muscovite from the Plélan granite, part of the Variscan Plélan-Bobital Granite Complex, yields a 40Ar/39Ar plateau age of c. 307 Ma.The 40Ar/39Ar results indicate that Cadomian rocks of the St Malo region have undergone a widespread and variable Palaeozoic (Carboniferous) rejuvenation of intracrystalline argon systems which apparently did not affect the Mancellian region. This rejuvenation was not accompanied by penetrative regional deformation, and was probably of a static thermal–hydrothermal origin. The heat source for rejuvenation was probably either the result of heating during Variscan extension or advection from Variscan granites which are argued to underlie the St Malo region.

Notes: Results of a short-term study of the revegetation of illegally rock-plowed wetlands in the East Everglades are reported. Comparisons of the plant communities on a restored site, an unrestored site, and the natural control areas directly adjacent to these sites were made using line intercept transects. On the site where removal of the rock-plowed material and grading of the surface to below original elevation were required for restoration, less than 20% of plant cover was of nonwetland species, and the occurrence of exotic species was low. On the rock-plowed site where no restoration efforts were performed, 61% of plant cover was of nonwetland species, and there was a higher occurrence of exotic species compared to the restored rock-plowed and the control sites.

Notes: The extreme species richness of native shrubland vegetation (kwongan) near Eneabba, Western Australia, presents a major problem in the restoration of sites following mineral sand mining. Seed sources available for post-mining restoration and those present in the native kwongan vegetation were quantified and compared. Canopy-borne seeds held in persistent woody fruits were the largest seed source of perennial species in the undisturbed native vegetation and also provided the most seeds for restoration. In undisturbed vegetation, the germinable soil seed store (140–174 seeds · m−2) was only slightly less than the canopy-borne seed store (234–494 seeds · m−2), but stockpiled topsoil provided only 9% of the germinable seeds applied to the post-mining habitat. The age of stockpiled soil was also important. In the three-year-old stockpiled topsoil, the seed bank was only 10.5 seeds · m−2 in the surface 2.5 cm, compared to 56.1 to 127.6 seeds · m−2 in fresh topsoil from undisturbed vegetation sites. In the stockpiled topsoil, most seeds were of annual species and 15–40% of the seeds were of non-native species. In the topsoil from undisturbed vegetation, over 80% of the seeds were of perennial species, and non-native species comprised only 2.7% of the seed bank. Additional seeds of native species were broadcast on restoration areas, and although this represented only 1% of the seed resources applied, the broadcast seed mix was an important resource for increasing post-mining species richness. Knowledge of the life-history characteristics of plant species may relate to seed germination patterns and assist in more accurate restoration where information on germination percentages of all species is not available.

Notes: The composition and structure of ant communities were used to assess the success of the preliminary restoration program at Ranger uranium mine in the seasonal tropics of northern Australia. Ants were surveyed at eight sites, including two relatively undisturbed control sits, within the Ranger lease. The revegetated sites represented a range of variables likely to influence restoration success: revegetation age (two, four, and eight years), proximity to undisturbed sites (which act as potential sources of recolonization), and burning treatment. Revegetation at most sites was dominated by fast-growing species of Acacia. There was a clear succession of ant species across revegetated sites. Initial colonization was by species of Iridomyrmex, but as plant cover and litter development increased these were replaced by broadly adapted, opportunist species, especially the introduced Paratrechina longicornis. Ant recolonization was very slow at isolated sites, with only 12 species present after eight years (the oldest site available). This compares with 21 species after only four years at a site located close to potential sources of recolonization. The ant community at this site, however, was very similar to that at another site located close to colonization sources, but eight years old. Ant succession therefore appeared to have stalled at this point, with species richness and composition bearing little resemblance to that at control sites. The heavy shade and litter produced by acacias were considered to be the major impediment to further change. Results from a site that had undergone a prescribed burn after two years, thereby breaking dominance by acacias and allowing for the establishment of a wide variety of plant taxa, suggest that such management practices may promote further colonization by ant species.

Notes: Soil microbial activity and soil nutrients were monitored on a revegetated coal surface mine in southwestern Wyoming from the initial planting in 1982 through 1987. Total soil nitrogen (N) and organic matter did not change during this period. However, despite no changes in available phosphorus (P) concentrations, the total P declined over 50% during the five-year period, with no apparent reduction in the loss rates. The greatest loss was in the bound inorganic P pool. Moisture appeared not to limit microbial mass-C. Microbial mass-C was higher under shrubs than in interspaces and increased with time. Total organic matter did not increase. Thus, the ratio of microbial mass-C to organic matter-C increased during the study period. This suggests that the input of readily decomposable substrate may limit microbial activity. During the study period, all above-ground litter was removed by wind. Root production in the surface soils was low and highly variable and, in this habitat, probably did not contribute largely to the organic matter status. These data suggest that despite an apparent recovery of many parameters used to indicate reclamation or restoration success, the soil-bound P pools could be undergoing a loss. Microbial-C and organic matter changes indicate a system that is not approaching equilibrium within the required monitoring period of most restoration efforts. These parameters could eventually reduce the recovery potential of restored sites.

Notes: A series of experiments designed to demonstrate the potential of using managed, attached algal production to permanently remove excess phosphorus from agricultural run-off is described. The experiments were carried out on a secondary canal in the New Hope South region of the Florida Everglades Agricultural Area from October, 1991, to May, 1992. Natural algal populations of periphyton, including species of the genera Cladophora, Spirogyra, Enteromorpha, Stigeoclonium, and a variety of filamentous diatoms such as Eunotia and Melosira, were grown on plastic screens in raceways, under a wave surge regime. Considerable biomass production of algae occurred, and the resulting algal canopy also trapped plankton and organic particulates from the water column. A seven- to eight-day harvest interval was determined to be optimal, and both hand harvesting and vacuum harvesting were employed. The vacuum device is applicable to large scale-up. In source water having total phosphorus concentrations of 0.012–0.148 ppm, mean macro-recovery dry biomass production levels of 15–27 g/m2/day were achieved. The lower rates occurred in the winter, the higher rates in the late spring. Two techniques were employed to reduce losses of fine material at harvest during the March to May period. Gravity sieving increased mean dry production levels to 33–39 g/m2/day. The mean phosphorus content of harvested biomass ranged from 0.34% to 0.43%. Total phosphorus removal rates during the spring period of average solar intensity and low nutrient supply, by methods demonstrated in this study, ranged from 104 to 139 mgTP/m2/day (380–507 kgP/ha/year). Over the incoming nutrient range studied, phosphorus removal was independent of concentration and was 16.3% of total phosphorus for 15 m of raceway. Up-stream-downstream studies of overflowing water chemistry (total P, total dissolved -P, orthophosphate -P) showed highly -significant reductions of all phosphorus species. Total phosphorus reduction closely correlated with phosphorus yield from biomass removal. Yearly, minimum phosphorus removal rates are predicted that are 100–250 times that achieved both experimentally and in long-term, large-area wetland systems. Engineering scale-up to systems of hundreds of acres is being studied.

Notes: The goal of this study was to use terrestrial arthropods to help evaluate the progress of a riparian restoration effort along the San Luis Rey River in California by comparing characteristics of the arthropod community at the reconstructed system to those of a naturally occurring riparian woodland used as a reference site. Insects and other arthropods were sampled throughout 1989–1991 using pan trapping and sweep sampling of dominant plants. Assemblages of taxa were monitored as indicators of functional groups that influence ecosystem processes: pollinators, herbivores, predators, parasites, and detritivores. Relative abundances of indicator assemblages were compared between sites to evaluate the establishment and maintenance of processes critical for the natural function of the reconstructed riparian ecosystem. A major objective of this project was to create habitat for the Least Bell's Vireo, so a group of potential prey items was designated to indicate vireo food resources. Over 230,000 arthropods were identified to order or family and by size. Insect communities developed rapidly at the restored habitat. Although the abundance of all arthropods was lower at the reconstructed site than at the reference site, the same orders were present after three years in similar proportions at both locations, and mean abundances were within an order of magnitude of each other. Abundance of certain groups, such as detritivores, suggested that arthropods had propagated rapidly at the restoration site, a possible indication of resiliency. Relatively low numbers of other arthropods, such as predators and parasites, at the reconstructed site indicated the need for continued monitoring. The decline of pollinators and herbivores by 1991 at the reconstructed site suggested that they may have immigrated or been introduced with transplanted vegetation in 1989, but have had difficulty colonizing the site. Although the Least Bell's Vireos were seen foraging at the restored site after three years, no nests were found. Nesting is anticipated, however, as the site matures.

Notes: We consider communication of quality via cheap talk and dissipative advertising expenditures, when consumers have heterogeneous tastes for quality, and price information must be acquired through costly search. For search pods, cheap talk communicates quality when fixed costs are roughly constant across quality levels, while if fixed costs vary greatly with quality, then firms having the higher fixed-cost quality level use dissipative advertising. For experience goods, quality can be communicated by cheap talk in a range where low-quality firms have greater fixed costs, and low-quality firms use dissipative advertising if their fixed costs are greater still.

Notes: We show that asymmetric information may prevent firms with pure discount bonds from renegotiating their capital structure prior to the maturity of the debt, although this would increase the value of the firm when its prospects are poor. This inefficiency can be reduced if the firm issues debt with a risky intermediate debt payment, such as a coupon or a sinking fund payment. We also demonstrate that bankruptcy institutions leading to deviations from absolute priority can improve the timing of recapitalizations by financially distressed firms. Finally, we show that, under certain conditions, the optimal capital structure adjustment during financial distress consists of a convertible debt-for-straight debt swap.

Notes: In the audit literature, it was postulated that audit firms are differentiated due to their quality and, thus, the fees charged are a function of quality. We hypothesize that this may lead to audit firm specialization in different amounts of auditing, leading to a differential audit fee structure. This hypothesis is empirically tested by using a very large sample of audit fees paid to then Big Eight auditors. The results are consistent with the hypothesis in that three Big Eight auditors are observed to charge significantly different fees when compared with the other firms.

Notes: This paper develops a simple model of sequential innovations with a diversity of research lines. Competitive strategies of firms for R&D are analyzed at each stage in a sequence of innovations. We compare two alternative regimes of enforcing patent law, as a mechanism to provide adequate incentives for R&D at each stage. The regime that protects the research line gives monopoly rights to an entire line of research, hence limiting the utilization of the previous knowledge and retarding subsequent innovations. The other regime protects the product, which facilitates the use of previous knowledge at the expense of providing inadequate protection to the ideas embodied in the product, and results in underinvestment in the first stage.

Notes: This article examines the role that multimarket operations play in a firm's ability to preempt entry into new markets when presence in a market does not commit the firm to remain there. Success in one market affects a firm's incentives and, in turn, strategic power, to fight a rival fur survival in a related market. This is modeled as a way of attrition, and the risk-dominant equilibrium is derived. The model supports brand proliferation as a credible preemptive strategy for an established firm and also has implications regarding the strategic role of economies of scope and “deep pockets.”

Notes: Economic transition in Eastern Europe should generate market growth. In addition, current discussions on economic integration and the development of a free-trade area in Eastern Europe will improve market accessibility. These two forces will significantly affect the strategies by which external firms will choose to supply markets in Eastern Europe. This paper examines the ways in which supply strategy is likely to change. We show that both market growth and improved market accessibility will lead the external firms to switch from exporting to foreign direct investment. However, market growth is likely to lead to dispersed investment in the growing economies, whereas increased market accessibility, by establishing an integrated regional bloc in Eastern Europe, is more likely to lead to concentrated investment plus infra-regional exports to the remainder of the regional bloc. The switch from exporting to local production through foreign direct investment will favor consumers through lowered prices but will harm national producers by depressing profit margins.

Notes: This paper demonstrates that, when the manager of a poorly performing firm generates firm-specific rents, strategic considerations associated with anticipated future restructuring may lead to the adoption of risky operating policies. Furthermore, this bias toward risky policies may be exacerbated by increases in managerial entrenchment. This is the case even when the manager does not have an ownership stake in the firm. On the other hand, a manager of a firm that is performing well will prefer safer policies. These results are driven by endogenously determined management-borne costs of financial distress, and obtain under both restructuring regimes that enforce the priority of creditor claims as well as restructuring regimes that induce deviations from absolute priority.

Notes: This paper considers an agency model in which a principal delegates an agent authority to choose investment projects. The performance of the project depends stochastically on the agent's evaluation and operating efforts. The paper examines the conditions under which the principal prefers to assign production to a second agent. It is shown that the tasks will be assigned to two agents of the agent chooses an unobservable operating effort. The tasks will be assigned to one agent if the agent's evaluation and operating efforts are both unobservable and if disutilities of efforts are large relative to the profit from the risky project.

Notes: It is well documented that a firm may choose to offer underpriced securities in an initial public offer. An open question is why investment banks do not retain underpriced offers in their portfolio. We argue that the distribution of underpriced securities allows banks of high qualify to signal their value to their customers, promoting in this way their other product lines. We show that the total dollar value of underpriced securities distributed (rather than the percentage value) acts as the signal. We also find that, all else equal, larger customers and those with more elastic demand functions receive n larger total dollar value of underpricing.

Notes: This paper develops a theory to explain the frequently observed resistance offered by the management of target firms to high-premium takeover bids. Contrary to the popular perception of managerial entrenchment at the expense of the shareholders' interests, such resistance may be strategically designed to increase shareholder wealth by threatening to initiate an informal auction process fur the target involving other potential bidders. Remarkably, this strategy can be effective even when it is common knowledge that the other bidders do not have a higher reservation price for the target. The analysis also offers insights into division of takeover gains and several other takeover-related issues.

Notes: I study how profit-maximizing organizations make decisions. Members of organizations tend to have incompatible preferences over decisions, but willingness to pay for decisions plays a very limited role in actual decision making. A sizable empirical literature documents that people who provide critical services, are hard to replace, or deal effectively with external shocks are powerful; they have disproportionate influence over decisions. This can be profit maximizing because the right to shape the firm through its decisions renders the firm more attractive as an employer. Thus, the relative costliness of employees' departures should affect their relative power.

Notes: Earlier mathematical models that have been developed for use with data acquisition/data reduction systems in close range photogrammetry have not taken into consideration the geometry of video imagery. In this paper, a recently developed multi-application collinearity equation (MACE) model is analysed and assessed. The model is simple to apply and is adaptable to any data acquisition/data reduction system in close range photogrammetry.

Notes: The use of CCD cameras for digital photogrammetry has only slowly been taken up by the photogrammetric community. However, the pace of change is quickening with better understanding and cheaper equipment. Recently a decision was made to start some research into close range three dimensional digital measurement. The overall objective was to develop a low cost system for the automated measurement of small industrial objects. This shorter contribution describes the initial stages of this work.

Notes: This paper presents two mathematical models of the accuracy of digital terrain model (DTM) surfaces which have been linearly constructed from square gridded data, respectively with and without additional feature specific data. In these models, the accuracy of DTM surfaces is expressed as a function of a few parameters, such as slope angle, grid interval or the accuracy of raw data, which are familiar to practitioners in photogrammetry and other mapping related disciplines. These models are in a form similar to the conventional formulae for contour map accuracy and they are compared with experimental test results.

Notes: In 1989, the Council of the Photogrammetric Society decided that some record of the use of analogue photogrammetric equipment in Great Britain should be preserved before it was too late. The author agreed to investigate this matter as a research project funded by a number of survey organisations. Work on the project so far has resulted in the completion of two documents. The first is a Catalogue of Analogue Instruments that list some 230 instruments of 30 different types. The second is an Archive that gives further details of the history and use of the 30 different types of instrument. The entry included in his paper, by way of example, is that concerned with the Zeiss Stereoplanigraph.Readers are encouraged to provide corrections and additional information wherever possible.

Notes: Feature extraction is the first and crucial step of all image analysis procedures. Together with their mutual relations, features form perceptual structures on which hypothesis generation and reconstruction processes are built. The article gives a framework for feature extraction within an interpretation system, discusses a possible object and image model useful for building up perceptual structures and gives examples for the use of various features for standard photogrammetric tasks.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméĽextraction automatique de silhouettes est la première étape fondamentale dans tout procédéďanalyse ďimages.Ces silhouettes constituent, en même temps que leurs relations mutuelles, des structures identifiables à partir desquelles on peut établir des hypothèses et procéder à la re constitution. On donne dans cet article un cadre général pour ľextraction de silhouettes dans un système ďinterprétation et ľon y discute ďune modélisation possible de ľimage et de ľobjet pour obtenir des structures identifiables. On fournit enfin des exemples sur ľemploi de diverses silhouettes d̄objets dans les travaux photogrammétriques courants.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungDie Kantenextraktion stellt den I. wesentlichen Schritt aller Bild-analyseverfahren dar. Gemeinsam mit ihren wechselseitigen Beziehungen bilden die Kanten wahrnehmbare Strukturen, auf denen Hypothesen und Rekonstruktionsprozesse aufgebaut werden können. Im Artikel werden ein Grundgerüst z.ur Kantenextraktion angegeben, mögliche Objekt- und Bild-modelle zur Entwicklung von Wahrnehmungsstrukturen diskutiert und Beispiele zur Nutzung verschiedener Kanten für photogrammetrische Standardaufgaben angegeben.

Notes: Accurate and rapid planning techniques are of vital importance when competing for business in the deregulated telecommunications market. This requirement, together with the arrival of personal communication networks, demands more detailed spatial data than are available now. This paper examines difficulties in current planning methods and considers the specifications of future data sets. 〈section xml:id="abs1-2"〉〈title type="main"〉Résumé Les méthodes de planification précises et rapides sont ď une importance vitale lorsque ľ on est en concurrence en affaires dans le marché déréglementé des télécommunications. Ce besoin, parallèlement àľ arrivée des réseaux personnels de communication, nécessite une disponibilité de données tridimensionnelles beaucoup plus détailées que celles que ľ on a actuellement. On examine dans cet article les difficultiés rencontrées dans les méthodes actuelles de planification, et ľ on réfléchit sur les spécifications des jeux de données dans ľ avenir. 〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Genaue und schnelle Planungsverfahren sind beim Geschäftswettbewerb aufdem nicht regulierten Telekommunikations-Markt von auβerordentlicher Bedeutung. Diese Anforderung in Verbindung mit dem Aufkommen von Personal-Kommunikations-Netzwerken erfordert detailliertere Raumdaten ah jetzt verfügbar sind. In dem Artikel werden die Schwierigkeiten der gegen-wärtigen Planungsmethoden geprüft und Anforderungen an künftige Datensätze erörtert.

Notes: The President's Medallist directs the Survey Services Branch of the Technical Services Group of English Heritage. This Branch includes the Photogrammetric Unit which was first established at the Institute of Advanced Architectural Studies of the University of York in 1975, with support from English Heritage's predecessor organisation. The Unit has played a leading part in the development of architectural photogrammetry in the UK, with particular reference to the recording of ancient monuments and historic buildings. The writer discusses some aspects of the application of photogrammetry in this area, illustrating the modern photogrammetric product in comparison with 18th and 19th century pictures and prints from his own collection. 〈section xml:id="abs1-2"〉〈title type="main"〉Résumé C'est le titulaire de la Médaile du Président de notre Société qui dirige le Département de Levés du groupe des services techniques du Patrimoine anglais. Ce Département comprend ľUnité de Photogrammétrie qui était installée initialiement àľInstitut des Études Architecturales Avancées ďYork en 1975, avec le soutien de ľorganisme qui précédait le Patrimoine anglais. Cette Unité a joué un rôle prépondérant dans le développement de la photogrammétrie architecturale au Royaume-Uni, et une mention particulière est à faire en ce qui concerne ľarchivage des constructions anciennes et des monuments historiques. Ľauteur discute de quelques aspects des applications de la photogrammétrie dans ce domaine, illustrant le produit photogrammétrique moderne par comparaison avec des tableaux et des gravures des 18èmeet 19ème siècles issus de sa collection personelle. 〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Der Träger der Präsidenten-Medaille leitet die Vermessungsabteilung innerhalb des Technischen Dienstes von English Heritage. Diese Abteilung schlieβt die Photogrammetrie-Einheit mit ein, die zunächst im Jahre 1975 im Institut für Moderne Architektur an der Universitat York mit unterstüt-zung der Vorgängerorganisation von English Heritage aufgebaut wurde. Diese Einheit hat eine führende Rolle bei der Entwicklung der Architektur-photogrammetrie im Vereinigten Königreich gespielt, wobei besonders altehrwürdige Denkmäler und historische Bauwerke aufgenommen wurden. Der Schreiber diskutiert einige Aspekte der Anwendung der Photogrammetrie aufdiesem Gebiet und illustriert das moderne photogrammetrische Erzeugnis im Vergleich mit Bildern und Kopien aus dem 18. und 19. Jahrhundert, die der eigenen Sammlung entstammen.

Notes: The reunification of Germany also paved the way for the reunion of Carl Zeiss in Jena and Oberkochen in 1991, after many months of negotiation. For the surveying and photogrammetry divisions, this means that a joint policy for development, production and marketing will be pursued in Jena and Oberkochen in the future. The two photogrammetry divisions in Jena and Oberkochen will continue to exist on the market, with both their advanced aerial survey cameras (LMK 2000 and RMK TOP) being available. While Oberkochen will concentrate on the further development of analytical plotters and aerial photograph rectification systems, Jena will increasingly specialise in software development, which is an expanding field. Due to its longstanding expertise in these fields, Jena will also continue its activities in the fields of interpretation and close range photogrammetry, including the taking and evaluation of images. 〈section xml:id="abs1-2"〉〈title type="main"〉Résumé La ré-unification de ľAllemagne a éalement ouvert la voie à celle des deux Zeiss, léna et Oberkochen, en 1991, après plusieurs mois de négotiation. Pour les divisions des levés et de la photogrammétrie, cela signifie qu ľon mènera dorénavant, à Iéna et à Oberkochen, une politique commune en ce qui concerne les developpements, la production et le marketing. Les deux divisions photogrammétriques, celle ďléna et celle ďOberkochen, continueront ďêtre présentes sur le marché, offrant toutes deux lews chambres photogrammétriques aériennes avancées LMK 2000 et RMK TOP. Tandis qu à Oberkochen on concentre les activités sur lapoursuite du développement des restituteurs analytiques et des systèmes de redressement des photographies aériennes, à léna on se spécialisera dans le développement des logiciels, domaine qui est en expansion. Etant donnée la compétence que ľon a acquise de longue date à Iéna dans le domaine de ľinterprétation et dans celui de la photogrammétrie à courte distance, on γ poursuivra les activités dans ces domaines, qui comprennent également la saisie et ľévaluation des images. 〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Die Wiedervereinigung Deutschlands bahnte im Jahre 1991 nach vielen Monalen der Verhandlung auch den Weg zur Vereinigung der Firmen von Carl Zeiss in Jena und Oberkochen. Für die Abteilungen Vermessung und Photogrammetrie bedeutet das, daβ in Zukunft für Entwicklung, Produktion und Vertrieb in Jena und Oberkochen eine abtestimmte Politik verfolgt wird. Die beiden photogrammetrischen Abteilungen in Jena and Oberkochen werden weiterhin mil ihren beiden Luftbildmeβkammern (LMK 2000 und RMK TOP) auf dem Markt vertreten sein. Wahrend sich Oberkochen auf die Weiterentwicklung analytischer Auswertegeräte und von Systemen zur Luftbildentzerrung konzentriert, wird sich Jena auf die Software-Entwicklung spezialisieren, was ein stark expandierendes Gebiet ist. Dank langjähriger Erfahrungen wird Jena seine Aktivitäten auf den Gebieten Photointerpretation und Nahbereichsphoto-grammetrie fortsetzen, wobei Bildaufnahme und Bildbewertung einges-chlossen sind.

Notes: The paper outlines the author's background and continuing education in photogrammetry. The potential of low cost instruments for non-specialists is examined from her viewpoint as a research student and as an employee of Leica UK Ltd. 〈section xml:id="abs1-2"〉〈title type="main"〉Résumé Ľarticle retrace les compétences acquises par ľauteur en photogrammétrie et lew prolongement en formation continue. Ľauteur présente également les possibilityé des appareils à bas prix pour les non-spécialistes en so plaçant à un double point de vue, en tant qu'tudiant faisant de la recherche et en tant qu'employee de la Société Leica Ltd. (RU). 〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung In dem Artikel werden die Ausbildung und die fortwährende Weiter-bildung der Autorin in Photogrammetrie skizziert. Der Nutzen preiswerter Gerdte für Nichtspezialisten wird unter ihrem Blickwinkel als Forschungs-student und Mitarbeiterin der Leica UK Ltd. beleuchtet.

Notes: Book Reviewed in this article:MONITORING BUILDING STRUCTURES. Edited by J. F. A. Moore.POSTCODES: THE NEW GEOGRAPHY. By J. F. Raper, D. W. Rhind and J. W. Shepherd.TEST OF TRIANGULATION OF SPOT DATA. Edited by I. J. Dowman.EUROPEAN SPACE DIRECTORY 1992. Seventh edition. Endorsed by Eurospace. Edited by D. Shirvanian.WISSENSBASIERTE METHODEN ZUR FERNERKUNDUNG DER UMWELT. Edited by O. Günther and W.-F. Riekert.PROCEEDINGS OF THE ISPRS AND OEEPE JOINT WORKSHOP ON UPDATING DIGITAL DATA BY PHOTOGRAMMETRIC METHODS, CHRIST CHURCH, OXFORD UNIVERSITY, ENGLAND, 15–17 SEPTEMBER 1991. Edited by P. R. T. Newby and C. N. Thompson.GLIMPSES OF WORLD WAR By W. P. Roe.A GUIDE TO MAP AND IMAGE PROCESSING By M. P. Skrdla.MULTIPHOTO GEOMETRICALLY CONSTRAINED MATCHING. By E. P. Baltsavias.DIGITALE PHOTOGRAMMETRIE IN DER DREIDIMENSIONALEN STRÖMUNGSMESSTECHNIK. By H.-G. Maas.LONDON. AN AEROFILMS GUIDE. By I. Thomson.THE SOUTH DEVON COAST PATH: AN AEROFILMS GUIDE. By D. Hannigan.THE COTSWOLD WAY: AN AEROFILMS GUIDE. By T. Fryer.THE SOUTH DOWNS WAY: AN AEROFILMS GUIDE. By J. Godfrey.SURVEYING. Sixth edition. By A. Bannister, S. Raymond and R. Baker.INSTRUMENT MAKERS TO THE WORLD: A HISTORY OF COOKE, TROUGHTON AND SIMMS. By A. McConnell.TRANSIT CIRCLE–THE STORY OF WILLIAM SIMMS 1793–1860. By E. Mennim.TERRA-1: UNDERSTANDING THE TERRESTRIAL ENVIRONMENT. THE ROLE OF EARTH OBSERVATIONS FROM SPACE. Edited by P. M. Mather.SPACE. By R. Gibson.KATASTER-ABC. Second edition. By O. Kriegel and D. Dresbach.

Notes: The ultrastructure of the life cycle of Vairimorpha necatrix (Kramer) was studied in Heliothis (Helicoverpa) zea larvae raised at temperatures ranging from 15° C to 30° C. In contrast to the description of the type species, both patterns of development (Nosema-like and Thelohania-like) that characterize the genus Vairimorpha were present at all temperatures examined. No temperature-related differences in the ultrastructure of Vairimorpha necatrix were observed; however, the effects of temperature variation were apparent in 1) the time between inoculation with V. necatrix and the initiation of the parasite life cycle and 2) the duration (or length) of the parasite life cycle. An additional form of the parasite, that of a diplokaryon in a sporophorous vesicle, was present during early sporogony. The nuclei of the diplokaryon separated followed by cytokinesis, forming two monokaryotic parasites, and eventually two plasmodia, within the sporophorous vesicle. This pattern of development is characteristic neither of Nosema nor Thelohania, nor has it been described for Vairimorpha.

Notes: Observations by electron microscopy were conducted on Coelosporidium periplanetae (Lutz & Splendore, 1903) Swarczewsky, 1914, an extracellular sporogenic protist in the lumen of the Malpighian tubules of Blatta orientalis Linn., 1758 and other domiciliary cockroaches. Results generally agreed with earlier studies by light microscopy but also allowed a more complete characterization of the species. Some outstanding features of the protist were: amoeboid multinucleate stages (plasmodia) capable of producing cytoplasmic projections for attachment to microvilli of tubules, endogenous formation of spores, differentiation of “generative” and “somatic” nuclei in plasmodia undergoing spore formation, polarized early sporoblasts (a nucleus on one half and a chondriome on the other), and biconcave, ovoid, non-polarized spores that are retained until maturation by the plasmalemma and residual cytoplasm of the original plasmodium. The new combination Nephridiophaga periplanetae is proposed based on this new, updated information. The family name Nephridiophagidae Sprague, 1970 is resurrected to include N. periplanetae and eleven other species of protists in the Malpighian tubules of arthropods, mostly insects in the orders Dictyoptera and Coleoptera. According to its characteristics, the family Nephridiophagidae cannot be included into any of the currently recognized phyla of protists. It is suggested that it should be temporarily treated as an incertae sedis group of Protista.

Notes: Direct observations of schizonts and agamonts releasing megalospheres clarified the asexual phase of the life cycle of Peneroplis planatus and made it most probable that this species has a paratrimorphic life cycle. Specimens with maximum lengths between 837 and 3,503 μm released about 500 to 1,500 megalospheric juveniles, which possessed two chambers (proloculi and flexostyles) prior to emergence from the parental shell. The presence of gamonts was not shown and was only implied by the occurrence of the agamonts. Since agamonts and schizonts have been found from December to May and since asexual reproduction occurs in spring in Elat, sexual reproduction probably occurs at another time of year (June to December). More detailed studies of this species need to be conducted throughout the year to improve our knowledge of the life cycle of this species.

Notes: . Ditrichomonas honigbergii n. g., n. sp. is a small trichomonad flagellate that has three emergent flagella arising from four basal bodies, a parabasal apparatus (single dictyosome with associated striated flagellar rootlets), a microtubular axostyle, a short undulating membrane, and hydrogenosomes. Cultures of D. honigbergii were isolated from the sediments of a freshwater lake and there is no known metazoan host. Cells form walled cysts with internalized flagella and go through all phases of the life cycle (excystment, binary division, encystment) without any perturbations to the culture medium. Ditrichornonas honigbergii is capable of ingesting and digesting bacteria by phagocytosis. These facts suggest that D. honigbergii may be a free-living inhabitant of oxygen-reduced environments. The structure of D. honigbergii is similar to that of retortamonads and the relationship of trichomonads to other amitochondrial protists is discussed.

Notes: . Tetrahymena thermophila mutants homozygous for the oad mutation become nonmotile when grown at the restrictive temperature, and axonemes isolated from nonmotile mutants lack approximately 90% of their outer dynein arms. Electrophoretic analyses of axonemes isolated from nonmotile mutants (oad axonemes) indicate they contain significantly fewer of the 22 S dynein heavy chains that axonemes isolated from wild-type cells (wild-type axonemes) contain. The 22 S dynein heavy chains that remain in axonemes isolated from nonmotile, oad mutants are assembled into 22 S dynein particles that exhibit wild-type levels of ATPase activity. Two-dimensional gel electrophoresis of oad axonemes show that they are deficient in no proteins other than those proteins thought to be components of 22 S dynein. This report is the first formal proof that outer dynein arms in Tetrahymena cilia are composed of 22 S dynein.

Notes: . A cell culture of Paramecium with a precise negative gravitaxis was exposed to 4 times 10-6g during a parabolic flight of a sounding rocket for 6 min. Computer image analysis revealed that without gravity stimulus the individual swimming paths remained straight. In addition, three reactions could be distinguished. For about 30 s, paramecia maintained the swimming direction they had before onset of low gravity. During the next 20 s, an approximate reversal of the swimming direction occurred. This period was followed by the expected random swimming pattern. Similar behavior was observed under the condition of simulated weightlessness on a fast-rotating clinostat. Control experiments on the ground under hyper-gravity on a low-speed centrifuge microscope and on a vibration test facility proved that the observed effects were caused exclusively by the reduction of gravity.

Notes: . The nuclear apparatus of H. vermiculare consists of a single moniliform macronucleus and about 25 micronuclei. the micronuclei are about 3 μm in diameter and characterized by a meshwork of thick condensed chromatin. Mitosis is intranuclear and acentric as in all other ciliates. In metaphase, interpolar and chromosomal microtubules are abundant and the length of the micronuclei increases to about 5 μm. In late anaphase, interzonal microtubules become prominent and the spindle elongates to about 50 μ. In meta- and anaphase, the microtubules of the spindle are attached to the polar vesicles, and in anaphase, chromosomes become attached to it. In contrast to most other eukaryotes, micronuclear mitosis is not strictly bound to cell division in H. vermiculare. While most of the micronuclei divide prior to cytokinesis, others retain their interphasic shape or degenerate. In addition, some micronuclei divide in the interdivision period, i.e. between two successive divisions of the cell and macronucleus. Mating cells of H. vermiculare become joined to each other in the cilia-free region covering the cytostome. In the course of conjugation, the cell membranes and the underlying oral filamentous sheaths of both cells fuse, thus uniting the endoplasm of both cells in the mouth region. Synaptonemal complexes in the meiotic chromosomes are more distinct in H. vermiculare than in most other dilates. the micrographs presented here depict dearly the central filament, transverse elements, and other substructures.

Notes: . Miamiensis avidus, a marine scuticociliate, undergoes microstome to macrostome transformation. This process is induced by prey ciliates. the morphogenesis of this process was examined using scanning electron microscopy and light microscopy of quantitative protargol-stained specimens. Several stages are identified and described.

Notes: . Scanning electron microscopic observations of feeding plasmodia show three characteristic features: 1) extension of multilobed pseudopodia protruding from the leading edge of the plasmodium as it advances onto the surface of a food particle, 2) confluence of the lobes to form a sheath-like pseudopodium attached to the surface of the food particle, and 3) protrusion of small nodules with thin lamellar projections from the leading edge of the plasmodium. Sections through freeze-dried preparations of the feeding plasmodium exhibit a highly convoluted under surface in contact with loosened starch grains that appear to be released by extracellular digestion. the cytoplasm, viewed by transmission electron microscopy, contains branched, internally penetrating canals (ca. 2 μm wide) enclosing engulfed starch grains. Starch grains in the deeper part of the canals are more electron dense and appear to be digested. Micropseudopodia (70-80 nm dia.), projecting from the surface of the canals, protrude toward and into the ingested starch grains. Digestive marker enzyme (acid phosphatase) activity was detected cytochemically in food particles penetrated by micropseu-dopodia indicating a digestive role for these structures not reported previously.

Notes: . Intestinal microsporidiosis in patients diagnosed with acquired immunodeficiency syndrome (AIDS) and having chronic diarrhea was first reported in 1985 and the associated microsporidian was named Enterocytozoon bieneusi. the intracellular developmental cycle of E. bieneusi in enterocytes has been demonstrated and many cases have been reported worldwide. This report presents the life cycle of a second intestinal microsporidian, associated with the same symptoms, in five AIDS patients. This new microsporidian also infects enterocytes but its pathology and morphology differ from that of E. bieneusi. It involves lamina propria macrophages, fibroblasts, and endothelial cells and can disseminate to infect other parts of the body, e.g. the kidney and gall bladder. the parasite cycle includes development of rounded uninucleate and elongated bi- or tetranucleate cells without the formation of plasmodial stages. Sporogony is similar to the more typical development of microsporidia with sporoblast morphogenesis occurring after the last cell division. the development of cells within chambers of a septate, honeycomb-like, parasite-secreted fibrillar network and surrounded by a parasitophorous vacuole, however, is unique to this microsporidian, justifying the establishment of a new genus and species, Septata intestinalis n. g., n. sp.

Notes: Spores of the microsporidian parasitic protozoan Encephalitozoon hellem were purified and incubated at 37° C in a solution with an electrolyte composition similar to that of mammalian extracellular fluid, and in solution in which the calcium had been replaced with 0.2 mM EGTA. Polar filament extrusion (germination) was monitored by both scanning electron microscopy and light microscopy. Germination was pH-dependent, with optima at pH 7.4 and 9.5, and was significantly greater in the presence of medium calcium. Hydrogen peroxide caused a concentration-dependent increase in germination that was also reduced in a calcium-free medium. Four agents were found to inhibit spontaneous and H2O2-stimulated polar filament extrusion: the microfilament disrupter, cytochalasin D; the microtubule disrupter, demecolcine; the calcium channel blocker, nifedipine; and the antifungal agent, itraconazole. These results are consistent with the existence of a calcium-channel-mediated step, and requirements for an F-actin- and for a tubulin-containing element in the germination process of the spore of this parasite. Nifedipine, cytochalasin D and itraconazole all have different sites of action and were therefore able to potentiate one another when used in paired combination to inhibit germination.

Notes: Pneumocystis carinii organisms were isolated from viral antibody-negative rats that had been infected by intratracheal intubation of organism preparations tested negative for common bacteria and fungi. Infection scores of lungs from infected animals at the time of parasite isolation was 〉 5 (100-1,000 organisms/oil immersion field). Electron microscopy of heavily infected lungs revealed that the pathogens adhered to Type I pneumocytes and to each other, resulting in obstructions up to several cell layers thick, which extended into the alveolar lumen. Protocols for purifying the organisms were developed to optimize separation from each other and from host cells, and to optimize preparation purity, recovery efficiency, and organism viability. The study tested mucolytic agents, sieving, various centrifugation speeds, lysis of host cells by osmotic shock and filtration through membranes of different pore diameter. Final preparations contained no intact host cells as determined by light microscopy. Only minor amounts (〈 5%) of host debris were detected by electron microscopy. Most organisms and their pellicles were ultrastructurally intact but no longer adhered to one another. The final preparation was characterized biochemically by quantitation of the specific lung surfactant marker surfactant protein A, which indicated 〉 99.5% purity. The total non-P. carinii protein in the final preparation (〈 6%, depending on the level of infection) was estimated by the protein content of pelletable material resulting from processing uninfected lungs in an identical manner. Elimination of free cholesterol and phospholipids from host lung tissue was monitored during the purification process. Exogenous stigmasterol, added as an extracellular marker, decreased during the purification process and was undetectable in the final organism preparation. Yields of 108-109 organisms/rat were routinely obtained. Viability, assessed by the calcein acetoxymethyl ester-propidium iodide assay, was 80–95%.

Notes: Pneumocystis is a eukaryotic microbe that causes pneumocystosis, an AIDS-associated pneumonia. Pneumocystosis also occurs in many other mammalian species, and animal-derived organisms have been extensively utilized in Pneumocystis research. Pneumocystis from diverse hosts contain a large glycoprotein (gpA/MSG) on the surface. Antibodies elicited against gpA/MSG of Pneumocystis from humans sometimes cross-react with epitopes on proteins of similar size from Pneumocystis from other host species. Here we report the isolation and partial sequence of two presumptive gpA/MSG genes from human-derived Pneumocystis. The cloned human-derived Pneumocystis gpA/MSG genes and predicted peptides were different from those previously isolated from Pneumocystis from rats and ferrets. The genome of human-derived Pneumocystis contained multiple copies of sequences related to the two cloned gpA/MSG genes.

Notes: . Trypanosomatids isolated from corn seeds and from digestive tract and salivary glands of Leptoglossus zonatus (Hemiptera, Coreidae) were obtained in pure cultures. In experimental transmission, the flagellates present in naturally infected insects were able to infect laboratory-raised corn. A simplified liquid culture medium was established that increased parasite yield three- to five-fold. Cultured and cloned parasites, and forms found in insects and corn as well, were studied by light and electron microscopy. A remarkable finding was the observation that the cultured strain 163M bears a surface coat similar to that observed in naturally occurring African trypanosomes. but not observed in trypanosomes in vitro. Based on the biochemical characteristics of the arknine-ornithine cycle and on the presence of this cell coat, we propose that the strain 163M is a new species and name it Herpetomonas macgheei n. sp.

Notes: . Expression of a 21 kDa determinant (Pbs21), first detected on the surface of ookinetes, and of the circumsporozoite protein (CSP) was studied by immunofluorescence and Western blots during the developmental cycle of Plasmodium berghei in the mosquito A nopheles stephensi. The expression of Pbs21 was predominantly localised on the ookinete surface one day after the infectious blood meal, and thereafter reactivity declined to a minimum on days 2 and 3, the time of onset of oocyst development. A gradual increase in fluorescence was observed on the oocysts from day 6 that was retained until day 17 post-infection. In contrast, sporozoites released from oocysts or salivary glands showed little or no antibody labelling with anti-Pbs21. Circumsporozoite protein was not detectable in any rnidgut preparations until 5–6 days after feeding, when reactivity was observed against immature oocysts. Expression then continued and increased throughout oocyst and sporozoite development. Western blots confirmed that Pbs21 was expressed minimally during the oocyst development but was not detectable in sporozoites. Co-localisation of anti-Pbs21 and anti-CSP monoclonal antibodies to the 50 kDa and 60 kDa bands in Western blots of sporozoite suggests immunological cross-reactivity between the CSP and the anti-21 kDa antibodies.

Notes: . The amoebae, a phenotypically diverse, paraphyletic group of protists, have been largely neglected by molecular phy-logeneticists. To better understand the evolution of amoebae, we sequenced and analyzed the 16S-like ribosomal RNA genes of three vahlkampfiid amoebae: Paratetramitus jugosus, Tetramitus rostratus and Vahlkampfia lobospinosa. The Vahlkampfiidae lineage is monophyletic, branches early along the eukaryotic line of descent, and is not a close relative of the multicellular amoebae that also reversibly transform from amoebae to flagellates.

Notes: . The “flagellates” as a taxon has become obsolete and should be dispensed with. It is obsolete because it is not phylo-genetically coherent. Adopting an ultrastructural perspective, it is argued that the flagellates exemplify an extreme case of paraphyly. Meaningful discussion of the evolution or ecology of flagellates can only emerge after we identify the monophyletic constituents of the flagellates. There are over 40 known types of heterotrophic flagellates and these should form the basis of a new understanding of flagellate diversity.

Notes: . A soluble enzyme amylopectin synthase (UDP-glucose-α 1,4-glucan α-4-glucosyltransferase) which transfers glucose from uridine 5′-diphosphate glucose (UDP-glucose) to a primer to form α-I,4-glucosyl linkages has been identified in the extracts of unsporulated oocysts of Eimeria tenella. UDP-glucose and not ADP-glucose was the most active glucosyl donor. Corn amylopectin, rabbit liver glycogen, oyster glycogen and corn starch served as primers; the latter two were less efficient. The enzyme has an apparent pH optimum of 7.5 and exhibited typical Michaelis-Menten kinetics with dependence on both the primer and substrate concentrations. The Michaelis constants (Km). with respect to UDP-glucose, was 0.5 mM; and 0.25 mg/ml and 1.25 mg/ml with respect to amylopectin and rabbit liver glycogen. The product formed by the reaction was predominantly a glucan containing α-1,4 linkages. The specificity of the enzyme suggests that this enzyme is similar to glycogen synthase in eukaryotes and has been designated as amylopectin synthase (UDP-glucose-α-1,4-glucosetransferase EC 2.4.1.11).

Notes: . The recently established protozoan phylum Opalozoa Cavalier-Smith 1991 includes all those zooflagellates with tubular mitochondrial cristae that never have cortical alveoli or rigid tubular ciliary hairs (retronemes), and also the opalinids, proteomyxids sensu stricto, and plasmodiophorids. Opalozoa totally lack plastids but usually (though not invariably) have peroxisomes. They always have well-developed Golgi dictyosomes. The trophic phase is a unicellular ciliated phagotroph except in the only intracellular parasites, the plasmodiophorids, where it is a non-phagotrophic and non-ciliated microplasmodium, and in the proteomyxids where it is an amoeboflagellate (which may sometimes be nonciliated) or a multicellular meroplasmodium. Unlike the phagotrophic Mycetozoa, opalozoans do not form aerial fruiting bodies, but encystation is common. The first detailed classification of the phylum is presented here. It is divided into four subphyla (three new), eight classes (four new, one emended), three subclasses (all new), three superorders (all new) and 22 orders of which 12 are new and one is emended. Diagnoses of these taxa are given, as well as lists of the 31 families (11 new) and 62 genera included within them. Opalozoa, which include Cercomonas and Heterornita, the commonest soil flagellates, are ecologically and evolutionarily important.

Notes: . Two new hemimastigophoran flagellates are described using light and electron microscopy, and the family Spironemidae is revised. Spironema terricola n. sp. occurs in soil from the Grand Canyon (southwest USA). It moves in a conspicuously euglenoid manner and differs from S. multiciliatum Klebs by its vermiform shape and shorter kinetics. Spironema terricola is similar to Goodey's Spironema multiciliatum from soil in England. However, Goodey's vermiform species has a very elongate nucleus and is thus neither identical with S. terricola, which has a roundish nucleus, nor with Klebs' lanceolate S. multiciliatum; we consider it a new species, Spironema goodeyi n. sp, Stereonema geiseri n. g., n. sp. was discovered in the Aufwuchs (periphyton) of a river in Bavaria, Germany. the new genus differs from Spironema by its a contractility, and from Hemimastix by its shorter kinetics and less plicate cortex. the fine structure of Spironema and Stereonema is very similar to that of Hemimastix Foissner et al., viz., the cortex is composed of two plates having diagonal symmetry and the flagellated basal bodies have associated a short and a long microtubular ribbon. All species have unique extrusomes of the same type. the main differences between the three genera and five species recognized are contractility, length of kinetics, body size, shape of cell and nucleus, and particulars of the cortex and extrusomes. the phylogenetic relationships of the Hemimastigophora are still uncertain. However, the diagonal symmetry of the cortical plates and the pronounced euglenoid movement of Spironema spp. suggest a common ancestor with euglenids.

Notes: . The replication band is a large, migrating, macronuclear domain that is the site of DNA synthesis in hypotrichous ciliated protozoa. A number of agents that produce inactivation of this structure and its replicational activity are described here. These agents include heat shock, aphidicolin, cell crowding, various cAMP phosphodiesterase inhibitors and a calmodulin inhibitor. With the exception of aphidicolin, which has a direct inhibitory effect upon DNA polymerases, the mechanisms of inactivation are presently unknown. the inactivating properties of cAMP phosphodiesterase inhibitors suggest that intracellular cAMP levels may influence replication band structure and function.

Notes: . The ultrastructure of the oral region and the ultrastructural architecture of the basket of Prorodon aklitolophon and Prorodon teres are described. the oral region of Prorodon consists of: 1) A circumoral kinety at the anterior pole of the cell surrounding the typically slit-shaped cytostomial funnel. This kinety is composed of inversely oriented dikinetids in which both kinetosomes are ciliated and are associated with a very short postciliary microtubular ribbon and a few transverse microtubules; 2) Three brush rows aligned in parallel and extended meridionally in the anterior part of the cell. the individual brush rows consist of dikinetids, but in contrast to the dikinetids around the cytopharynx they are not inverted and only the anterior kinetosomes bear specialized short brush cilia and are associated with a divergent-tangential transverse microtubular ribbon. the posterior kinetosome is non-ciliated and bears a prominent convergent postciliary microtubular ribbon. Schematized dikinetid patterns of both oral regions of Prorodon are provided. In addition, a three-dimensional reconstruction of the basket of the genus Prorodon based on serial thin sections is presented. A phylogenetic tree, mainly based on stomatogenic data, is given to show the phylogenetic relationships of some prostomatid genera as well as the hypothesized sistergroup relationship of colpodid and prostomatid ciliates.

Notes: . This study describes the ultrastructure of the somatic cortex of Prorodon aklitolophon and Prorodon teres. the meridionally arranged somatic kineties of both species can be separated into two parts: a short anterior part, which consists of a few somatic dikinetids (in which both kinetosomes are ciliated), and a longer posterior consisting of monokinetids. the somatic monokinetids are associated with a convergent postciliary microtubular ribbon, a transverse microtubular ribbon flatly inserted in front of the kinetosome, a short and steeply extending kinetodesmal fibre attached to kinetosomal triplet 5 and 7, and a desmose anterior to triplet 3. From this desmose, two to five prekinetosomal microtubules originate and extend anteriorly. the posterior kinetosome of the somatic dikinetids is associated with the same microfibrillar and microtubular structures as the somatic monokinetid, except that no prekinetosomal microtubules originate from the desmose. the anterior kinetosome has a single postciliary microtubule and a tangentially oriented transverse microtubular ribbon. the permanent collecting canals of the unique contractile vacuole system extend parallel and adjacent to the somatic kinetics of Prorodon. the collecting canals are supported by the prekinetosomal microtubules. A similarly organized contractile vacuole system is not yet known from any other ciliate group. One of the most surprising results of this investigation was finding a significant similarity between the somatic dikinetid pattern of Prorodon and the colpodid dikinetid pattern. A hypothesis is presented to illustrate the evolution of the somatic kinetid patterns in colpodid and prostomatid ciliates.

Notes: . The morphological characteristics of two new species of Isospora observed in Emberiza cirlus (Cirl Bunting) from Italy are reported. the oocysts of Isospora normanlevinei n. sp. are spherical or sub-spherical, with a smooth double-layered wall, and measure 24.2 times 23.7 (21.0-26.5 times 21.5-25.5) μm; each oocyst contains 2 to 10 polar granules. No micropyle or residuum was observed. the piriform sporocysts measure 19.4 times 11.2 (17.0-21.0 times 10.0-12.5) μm and contain a dispersed residuum. the Stieda body is flat; the substiedal body, with scattered clear and dark granules, may be either symmetrical or asymmetrical. the oocysts of I. coluzzii n. sp. are asymmetrical and rounded shape and measure 28.6 times 24.2 (25.0-31.5 times 21.5-26.0) μm. the oocyst has a double-layered wall and 2 to 3 polar granules. Neither micropyle nor residuum is present. the sub-ellipsoidal sporocyst, measuring 18.2 times 10.0(16.5-20.0 times 9.0-11.0) μm, has a dispersed sporocyst residuum. the Stieda complex is symmetrical.

Notes: . Free-living amoebae belonging to the species Naegleria fowleri are known to be the etiological agents for a form of fulminant meningoencephalitis that is generally fatal (primary amoebic meningoencephalitis). In a broad bacterial screening from soil and water we have isolated three strains (M-4, D-13 and A-12) belonging to the species Bacillus licheniformis that have remarkable amoebicidal activity against Naegleria sp. and also against different Gram-positive and Gram-negative bacteria. Physical-chemical characteristics, partial purification and biological activities of a substance produced by the M-4 strain have been investigated. This substance (m-4) is stable at high temperature (up to 100°C) and extremes of pH (2.5-9.5) and also at -20°C for months. Its production is greatly influenced by oxygenation of the cultures and is probably related to the sporulation process of the bacterium. Scanning electron microscope observations reveal that amoebae are lysed after a few minutes contact with m-4.

Notes: . Rhodamine 123, a membrane potential-specific dye, has been evaluated as a probe to monitor the function of the mitochondrion in long slender bloodstream and procyclic trypomastigotes of several Trypanosoma brucei spp. By epifluorescence microscopy, mitochondrial development has been followed in long slender bloodstream and procyclic organisms stained with rhodamine 123. to photograph stained long slender bloodstream forms, it was necessary to develop a method to completely immobilize viable organisms. In both parasite forms, as the cell cycle progressed, the mitochondrion developed from a thread-like structure to a highly branched organelle. A dramatic reorganization occurred preceding cytokinesis to produce two progeny thread-like structures which were partitioned into newly formed daughter cells. the organelle within the long slender trypomastigote was found to stain optimally at 0.3 μ/ml of rhodamine 123, while the procyclic form required 3.0 μ/ml. the results suggest that the plasma membrane potential is higher in the long slender parasite than in the procyclic form. the effects of inhibitors that disrupt mitochondrial function were examined in long slender and procyclic parasites, and some of these agents were shown to affect rhodamine 123 accumulation and retention. In long slender trypomastigotes the trypanosome alternative oxidase does not appear to be coupled to proton pumping, whereas in procyclic organisms the effects of inhibitors indicate that this oxidase may be coupled to a pathway that is branched preceding an antimycin A1-sensitive site.

Notes: . The biochemical characterizations of lipophosphoglycans from various Leishmania species reported by other workers may or may not contain several types of lipophosphoglycan molecules. This is the first report in which a specific lipophosphoglycan has been defined by both its antigenie and electrophoretic properties. Furthermore, a purification procedure for this specific lipophosphoglycan is described and some biochemical characterizations are presented. Phospholipase C and the so-called phosphatidylinositol-specific phospholipase C of Bacillus cereus convert the amphipathic form of the lipophosphoglycan antigen to the hydrophilic form. Under equivalent incubation conditions, other phospholipases tested were not effective in conversion of the amphipathic to the hydrophilic form. Since the amphipathic form is present in conditioned media, antigen shedding cannot be explained by phospholipase C digestion of the amphipathic form, which would result in the release of only the hydrophilic form into the medium. Both the pellet and the supernatant fractions of conditioned media contained both forms of the antigen and did not differ in the relative amounts of the two. This observation rules out membrane blebbing as the major mechanism for the release of the amphipathic form.

Notes: . A myosin-like protein (Mr 175,000) was detected in the parasitic protozoan Gregarina blaberae, by both immunofluorescence and immunoblotting of one- and two-dimensional electrophoresis gels using anti-myosin antibodies. This protein was present in the trophozoite ghost but not in the cytoplasmic extract, nor in extract from the sexual stage, suggesting a protein-stage-dependent expression. the protein tightly bound to the cortical membranes was insoluble at low ionic strength, or in detergent solutions, but could be extracted from Gregarina ghosts by 6 M urea in high ionic strength solution (0.5 M NaCI) and in the presence of reducing agents (20 mM DTT). the protein was localized by indirect immunofluorescence in the cortex of the epimerite, in the fibrillar disc (the socalled septum) separating the proto- and the deutomerite segments, in the contractile ring or sphincter at the top of the protomerite, and as longitudinal lines underlying the G. blaberae epicyte folds. the presence of both actin-like and myosin-like proteins would be consistent with a role in gliding and other cell motility processes of this parasite.

Notes: . Explaining the low incidence of invasive disease (10%) in humans infected with Entamoeba histolytica has occupied the attention of generations of both clinical and nonclinical investigators. One possible explanation would be the existence of two morphologically identical species—one an invasive pathogen, the other noninvasive. This was first proposed by Brumpt in 1925, but his explanation was virtually ignored until 1978 when the first of several publications appeared suggesting that E. histolytica did indeed consist of two species. We have reexamined Brumpt's claim in light of recent biochemical, immunological and genetic studies and conclude that the data derived from these investigations provide unequivocal evidence supporting his hypothesis. With this in mind, we redescribe the invasive parasite retaining the name Entamoeba histolytica Schaudinn, 1903 (Emended Walker, 1911), and set it apart from the noninvasive parasite described by Brumpt, Entamoeba dispar Brumpt, 1925.

Notes: . Vance Tartar (1911-1991) has made major discoveries concerning morphogenesis, patterning, and nucleocytoplasmic relations in the giant ciliate Stentor coeruleus, mostly by means of hand-grafting using glass microneedles. This article provides a chronological account of the major events of Vance Tartar's life, a brief description of some of his major scientific achievements, and a discussion of his distinctive personality and multifaceted interests. It concludes with a consideration of how his unique style of life and work contributed to his equally unique seientific contributions.

Notes: . Electron microsocpic investigations reveal that the Golgi apparatus of Tetrahymena thermophila consists of numerous tiny dictyosomes, each consisting of one or two cisternae. the dictyosomes are localized predominantly in the cell cortex closely associated with the mitochondria, arranged in meridians alternating with the ciliary meridians. We estimated about 300-400 of these dictyosomes in the periphery of a cell, a value corresponding to the number of somatic cilia per cell. Cytochemical assays of thiamine pyrophosphatase and acid phosphatase, both marker enzymes of trans Golgi cisternae, resulted in deposits of lead or cerium phosphate in the outermost cisternae of the dictyosomes. In addition, cisternae located at the bases of the basal body/parasomal sac arrangements are stained. This indicates that these cisternae may belong to the Golgi apparatus of the cell.

Notes: . The effects of different sulphonamides, dihydrofolate reductase inhibitors and other inhibitors of folate metabolism on growth of Acanthamoeba culbertsoni in a chemically defined medium are reported. Among the sulphonamides, sulphamethoxazole and sulphadiazine were most effective followed by sulphanilamide and sulphaguanidine. Inhibition by each sulphonamide was reversed by p-aminobenzoic acid as well as folic acid. 7-Methylguanosine, a pteridine synthesis-inhibitor, did not inhibit multiplication of A. culbertsoni. Among the dihydrofolate reductase inhibitors, pyrimethamine blocked the amoebic growth at 100 μg/ml, while trimethoprim and cycloguanil palmoate failed to cause significant inhibition of growth even at 250 μg/ml. Metoprine inhibited amoebic growth completely at 50 μg/ml. Methotrexate and a thymidylate synthetase inhibitor 5-fluorouracil inhibited growth strongly, with IC50 values (the concentration of the drug which causes 50% inhibition of the growth at 72 h) of 1.97 and 2.45 μg/ml, respectively. Inhibition by methotrexate, metoprine or 5-fluorouracil could not be reversed by folic acid, folinic acid, thymidine, or folinic acid plus thymidine. the results indicate unusual features in A. culbertsoni folate metabolism.

Notes: . Using monospecific antibodies, the presence and distribution of tubulin, actin, myosin, intermediate filaments, and lamins were examined in the exoerythrocytic liver schizont of Plasmodium berghei by conventional indirect fluorescent antibody methods and confocal laser scanning microscopy. the binding reactivity of the antibodies to parasite proteins was determined by Western blot analysis. the localisation of all antibodies in control host hepatocytes followed expected distributions in both uninfected and infected hepatocytes; by contrast, reactivity to the exoerythrocytic schizont was variable. the parasite reacted positively with selected anti-tubulin, -actin, and -myosin antibodies in both fluorescence and Western blot analysis. Anti-lamin antibodies were positive by confocal indirect fluorescent antibody labelling, but no labelling was detected with anti-intermediate filament antibody. Within the technical limits of resolution of the methods as applied to asynchronous parasite infections, not one of the antibodies reacting positively with the parasite by the indirect fluorescent antibody technique could be shown to identify unequivocally the classic architectural features associated with their respective target organelles, i.e. microtubules, stress-fibres or the nuclear envelope.

Notes: . Pyrimidine salvage enzyme activities in cell-free extracts of Toxoplasma gondii were assayed in order to determine which of these enzyme activities are present in these parasites. Enzyme activities that were detected included phosphoribosyltransferase activity towards uracil (but not cytosine or thymine), nucleoside phosphorylase activity towards uridine, deoxyuridine and thymidine (but not cytidine or deoxycytidine), deaminase activity towards cytidine and deoxycytidine (but not cytosine, cytidine 5′-monophosphate or deoxycytidine 5′-monophosphate), and nucleoside 5′-monophosphate phosphohydrolase activity towards all nucleotides tested. No nucleoside kinase or phosphotransferase activity was detected, indicating that T. gondii lack the ability to directly phosphorylate nucleosides. Toxoplasma gondii appear to have a single non-specific uridine phosphorylase enzyme which can catalyze the reversible phosphorolysis of uridine, deoxyuridine and thymidine, and a single cytidine deaminase activity which can deaminate both cytidine and deoxycytidine. These results indicate that pyrimidine salvage in T. gondii probably occurs via the following reactions: cytidine and deoxycytidine are deaminated by cytidine deaminase to uridine and deoxyuridine, respectively; uridine and deoxyuridine are cleaved to uracil by uridine phosphorylase; and uracil is metabolized to uridine 5′-monophosphate by uracil phosphoribosyltransferase. Thus, uridine 5′-monophosphate is the end-product of both de novo pyrimidine biosynthesis and pyrimidine salvage in T. gondii.

Notes: Miamiensis avidus is a marine polymorphic scuticociliate that undergoes microstome to tomite transformation when nutrients are depleted. This transformation takes place as a result of two consecutive divisions and does not involve a cyst. Tomitogenesis was induced by nutrient deprivation. When returned to nutrient medium tomites transformed into microstomes. Changes in population were noted at one-hour intervals. Tomites of Miamiensis avidus Ma/2 are compared to dispersal stages in other scuticociliates and hymenostomes.

Notes: Leishmania donovani promastigotes in late-stationary phase incorporated label from [2-14C]acetate and [1-14C]laurate into the mannose residues of mannan, thus confirming the presence of a functional glyoxylate bypass in these parasitic protozoa. Isolated, washed calls also incorporated label from [2-14C]acetate and [1-14C]laurate into mannan during a 1-hr incubation in buffer. Glucose had no effect on label incorporation into mannan, but glutamate caused over a four-fold increase in incorporation from [2-14C]acetate and a 2.4-fold increase from [1-14C]laurate. Staurosporine, a protein kinase inhibitor that inhibits glutamate and alanine oxidation, did not inhibit label incorporation from [2-14C]acetate into mannan. Hyperosmolality caused about a 33% inhibition of label incorporation into mannan. These results show the glyoxylate cycle and/or the subsequent biosynthetic pathway from fructose-6-phosphate to mannan are subject to regulation.

Notes: Pneumocystis carinii from rats and from humans were compared with respect to electrophoretic karyotype, presence of DNA sequences known to be repeated in rat-derived P. carinii, overall DNA sequence homology, and the sequences at two genetic loci. The organisms from each host species were different in each respect. Neither of two repeated DNAs from rat-derived P. carinii was found in the genome of human-derived organisms, and total DNA from rat-derived P. carinii failed to hybridize to human-derived P. carinii DNA. The sequences of the α-tubulin genes from the two P. carinii were strikingly different and the base composition of the α-tubulin gene from rat-derived P. carinii was rich in adenine and thymine, while the base composition of this gene from human-derived P. carinii was rich in guanine and cytosine. The sequence from the 18S rRNA gene of human-derived P. carinii was twice as divergent from that of rat-derived P. carinii as the sequence from the corresponding region of Candida albicans was from that of Candida tropicalis. These data show that rats and humans can harbor distinct types of P. carinii that are sufficiently different to suggest that P. carinii from the two hosts could be different species.

Notes: Six monoclonal antibodies (MAbs) were produced against a highly immunogenic fraction derived by the chromatographic separation of the soluble preparation of axenic Entamoeba histolytica (strain NIH:200) trophozoites. Isotype characterization of the six MAbs revealed that four belonged to the IgM class and one each to the IgG1 and the IgG2a subclasses. The immunoreactivity patterns and the specificity of the MAbs with homologous and heterologous antigens were analyzed by the enzyme-linked immunotransfer blot technique and by the enzyme-linked immunosorbent assay. The MAbs reacted intensely with isolates of E. histolytica (strain NIH:200 as well as a local isolate MX1) but showed no reactivity with Entamoeba coli, Iodamoeba butschlii, Endolimax nana, Entamoeba hartmanni, free-living amoeba (Acanthamoeba harticolus) and other enteric parasites. Using the IgG1 MAb as a detecting antibody, a polyclonal-monoclonal antibody-based enzyme-linked immunosorbent assay was developed for the detection of E. histolytica antigens in stool samples of infected patients. The detection limit of the assay was 8 ng of amoebic antigen. This test was found to be specific and sensitive and yielded 100% positive results in cases with amoebiasis but did not react with controls included in the evaluation. The MAb-based enzyme-linked immunosorbent assay developed in this study will be an important test for the diagnosis of E. histolytica in the feces of infected humans; however, the limitation of the test is the inability to discriminate the pathogenic status of the amoeba detected in the stool.