Eimeria nieschulzi: glucose absorption in infected rats

Liquid scintillation spectrophotometry was employed to determine absorption of ³H-glucose by rats infected with the coccidium Eimeria nieschulzi. In vivo studies showed increased uptake of label into small intestinal tissue and hepatic portal plasma at 3 days postinoculation and decreased absorption at 8 days postinfection compared to uninfected control animals. Observations of tissues incubated in labeled glucose in vitro confirm in vivo findings of increased uptake early in infection and malabsorption coinciding with the observation of clinical disease symptoms.     

Micro-autoradiographic studies on host-parasite interactions

Tritium labeled uredospores of Uromyces phaseoli were produced be feeding the host, Phaseolus vulgaris, with ³H-orotic acid. These spores were allowed to germinate on and to penetrate into a bean leaf. 24 hrs after inoculation, the bean rust had formed the first haustorium. All fungal structures, including the fungus walls, were heavily labeled. No label could be detected in the cells that had come into contact with the hyphae. In the infected host cell, the haustorium was labeled heavily, but the sheath around the haustorium and the host cell remained free of label. These results indicate that no detectable amounts of label leach from the bean rust into the host at this stage of infection although it is known that the rust takes up many metabolites. Since the sheath remains free of label and all fungal structures are evenly labeled, it is concluded that the sheath is formed by the host.     

Sugar uptake by the grape berry: A note on the absorption pathway

Summary ³H-glucose was fed to excised Sultana grape berries via their pedicels for up to 5 hours. Autoradigraphy showed that the label was distributed throughout the fruit within 1 hour. Microautoradiography of tissue sections taken at a number of points showed that within the pedicel the walls of cortical cells had become heavily labelled, suggesting that the cortical cell walls offered a diffusion pathway for the solutes entering the vascular system from the external aqueous solution. Transport along the pedicel was confined to the central vascular tissue with little radioactivity occurring in the cortical cells. Within the pericarp, the vascular bundles and walls of nearby parenchyma cells had become heavily labelled, indicating that the labelled solute was present within the vicinity of cell walls. The general pattern of ³H-glucose accumulation by excised berries was similar to the deposition pattern of ²⁴C-labelled photosynthate within attached fruit.     

Reversible independent alterations in glucose transport and metabolism in cultured human cells deprived of glucose

We have measured uptake of ³H-hexoses into diploid human cells by exposing them to brief pulses of isotopic sugar during the log-growth, subconfluent-growth, and confluent-growth (contact inhibited) phases of the strain HSWP derived from human skin. ³H-deoxyglucose appears to be taken up three times faster than ³H-glucose. After exposure to ³H-glucose for longer than one minute, the cells excrete ～70% of the isotope into the medium as lactate. If lactate production (and hence excretion) is abolished by treating the cells with iodoacetic acid or dinitrofluorobenzene, neither of which inhibits transport, the uptake of ³H-glucose is found to be in fact somewhat larger than that of ³H-deoxyglucose. If cells are deprived of glucose for 24 hours, apparent uptake of ³H-glucose is enhanced 10-fold or more. This latter increase is accounted for by 2- to 3-fold enhancement of true transport plus retention of > 90% of the radioactivity, since little lactate is formed or excreted in glucose-deprived cells. Deoxyglucose, galactose, or pyruvate when present during glucose deprivation each have quantitatively different effects on the cells' capacity to produce lactate from a short pulse of glucose, but none of them prevents the enhancement of hexose transport. After restoration of 5 mM glucose to starved cells, their metabolism returns to normal (in the sense that ～70% of the glucose taken up in a pulse is again excreted as lactate), with a half-time of 0.5 hour; but the transport of hexoses returns to control levels much more slowly, with a half-time of ～6 hours. The two processes appear to be independently regulated.     

Glucose metabolism in the basal state and during a two-hour glucose infusion in low insulin responders and control subjects

Glucose metabolism was studied in eight low insulin responders to glucose and eight controls using a primed-constant tracer infusion technique. The tracer was 3-3H-glucose. The former group demonstrated a lower IVGTT than the controls, although the K-values were well within the normal range. They also attained higher blood glucose levels during iv administration of high and low glucose loads. Glucose turnover studies revealed normal hepatic glucose production, normal total glucose uptake and normal metabolic clearance of glucose in the low responders as a group. The findings suggest normal sensitivity to insulin in these subjects, and imply that the low insulin response is the sole mediator of the observed lowering in IVGTT.     

Numbers and viability of bacteria in ornithogenic soils of Antarctica

Summary Bacteria in ornithogenic soils from Ross Island, Antarctica, were counted by direct observation, and the percentages of viable organisms were assessed by incubation with ³H-glucose and by enumerating numbers of colony-forming units. The effects of incubation times and temperatures, and of storage of the samples, on the uptake of ³H-glucose were determined. Direct counts showed that large total numbers of bacteria were present in samples from occupied penguin colonies and recentlyabandoned sites. The percentages of bacteria metabolizing ³H-glucose increased when incubation was extended from 2 h to 8 h at field (average 4–5°C) or laboratory (average 18.5°C) temperatures to a maximum of 22%; storage of the samples for 31 days had no significant effect. The numbers of colony-forming units (CFU) were less than 0.058% of the direct counts. There were 77 times as many CFU in samples from the abandoned site compared to the inhabited colony. About 10% of the CFU were cocci compared with about 48% visible by direct microscopy. The glucose utilization data indicated that far more of the bacteria were viable than were cultured.     

THE UPTAKE AND DEVELOPMENT OF VACCINIA VIRUS IN STRAIN L CELLS FOLLOWED WITH LABELED VIRAL DEOXYRIBONUCLEIC ACID

Vaccinia virus which had its DNA labeled with thymidine-H³ was purified and used as inoculum for L cells growing in suspension. Samples taken over an 8-hour period after infection were studied by light and electron microscopic autoradiography. Within 20 minutes of its being taken up at the cell membrane in phagocytic vesicles, the outer coat of vaccinia becomes disrupted and the virus core containing the labeled DNA passes into the cytoplasmic matrix. Within 1 hour after inoculation the labeled material passes out of the cores into zones of viroplasm, where cores or remnants of cores are gathered and the label becomes more concentrated by 3 hours after inoculation. Most of the label is conserved in the viroplasm areas during the remainder of the experiment. However, 6 hours after inoculation a very small proportion of progeny virus in the cytoplasm, morphologically distinct from the cores of the inoculum, has associated with it labeled material, perhaps derived from the DNA of the inoculum.     

The uptake,distribution, leakage,and incorporation of32P into organic compounds in alfalfa plants susceptible and resistant to the bacterial wilt and the effect ofCorynebacterium insidiosum upon these processes

Higher³²P uptake per plant was found in the healthy resistant (R) alfalfa (Medicago saliva L.) plants when compared with the healthy plants susceptible (S) to the bacterial wilt, following the exposure of the roots of intact plants to the radiophosphate solution. The bacterial infection markedly decreased³²P uptake and radioactivity levels per dry matter in most organs of the R-plants on the day 8 and 14 after inoculation withCorynebacterium insidiosum whereas in the S-plants a decrease in³²P uptake was only found on the day 8.³²P leakage rate from the infected R-plant roots to the nonradioactive nutrient solution was higher than from the healthy ones on the day 8. At the same time³²P content in the organic P fraction was somewhat increased due to the infection in the R-plant roots, whereas³²P content in DNA was decreased. After foliar application,³²P distribution pattern was similar in the tissues of both the S- and the R-plants and was not affected due to the infection in the course of the 3rd week after inoculation. However, the bacterial infection markedly increased³²P translocation from the primary leaf to the rest of the R-plant. An erratum to this article is available at .     

Cupular secretion by Xenopus laevis line organs: autoradiographic evidence for incorporation of 3H-glucose and 35S-sulfate

Autoradiographic evidence for incorporation of 3H-glucose and 35S-sulfate into the cupulae of Xenopus laevis (African clawed toad) lateral line organs was obtained after injection into the dorsal lymph sacs of adult animals. Time intervals of 15 minutes to 4 hours after administration of these labeled metabolic precursors were used to examine the time course of the apparent mechanism of growth of the cupulae. Our results suggest that the two layers of accessory cells (the sustentacular cells and inner layer of mantle cells), concentrically arranged around the organ's central sensory (hair) cells, elaborate distinct cupular components. Sustentacular cells, immediately adjacent to the sensory cells, appear to produce and extrude at their exposed apices a cupular "core" substance labeled by 3H-glucose, but not by 35S-sulfate. The layer of inner mantle cells, external to the sustentacular cells, was labeled by both precursors and is spatially situated to secrete a cupular sheath enclosing the cupular core. Ultrastructural differences between the secretory products within the two cell types were marked. Electron microscopic autoradiography of toads killed 4 hours after 3H-glucose injection showed that silver grains were associated with accumulations of the respective secretory products in sustentacular and inner mantle cells, and label was found over the cupular trough area, where the bases of the cupulae are attached. These results suggest that the cupular core and sheath may both contain mucopolysaccharide, and the sheath, a sulfated mucopolysaccharide.     

Abundance and distribution of bacterioplankton in the Gambia River,West Africa

Four ecological zones of the Gambia River were sampled during four different hydrologic seasons for determination of microbial, nutrient, and physical parameters. A Greco-Latin Square experimental design was used to define the particular transect, station, depth, and tide/time-of-day of samples taken. Ranges of total bacterioplankton densities (10⁶ cells/ml) were similar to those of tropical and temperate environments. Numbers of free bacteria were similar temporally, whereas attached bacteria numbers were greater during periods of high stream flows when suspended solids concentrations were higher. Free bacteria were usually twice as numerous in the freshwater zones than in the estuarine zones. Attached bacterial densities were approximately four times greater in the estuarine zones than in the freshwater zones. Uptake of³H-glucose on both a sample volume and per-cell basis increased from the early stages of the flood (6.95±SE 1.37 ng/liter/hour and 3.8 pg/hour/10⁶ cells, respectively) and reached observed annual maximums during the dry season (21.01±SE 3.05 ng/ liter/hour and 13.0 pg/hour/10⁶ cells, respectively). Spatially,³H-glucose uptake per sample volume and per cell was highest in the upper river zone and lowest in the lower estuary zone. The lower estuary zone consistently acted out of concert with the other river zones in terms of³H-glucose and¹⁴C-bicarbonate uptake. Analysis of variance (ANOVA) indicated that free and attached bacterioplankton densities were not homogeneous among transects, stations, depths, and tide/time-of-day at the different zones during the four hydrologic seasons. The results suggested that heterotrophy overshadowed autotrophy in the river and that the bacterial abundance, distribution, and glucose uptake activity in this tropical floodplain river were greatly influenced by the annual flood and the presence of extensive mangrove forests in the estuary.     

Loss of exudates from the roots of perennial ryegrass inoculated with a range of micro-organisms

To determine the effect of microbial metabolites on the release of root exudates from perennial ryegrass, seedlings were pulse labelled with [¹⁴C]-CO₂ in the presence of a range of soil micro-organisms. Microbial inoculants were spatially separated from roots by Millipore membranes so that root infection did not occur. Using this technique, only microbial metabolites affected root exudation. The effect of microbial metabolites on carbon assimilation and distribution and root exudation was determined for 15 microbial species. Assimilation of a pulse label varied by over 3.5 fold, dependent on inoculant. Distribution of the label between roots and shoots also varied with inoculant, but the carbon pool that was most sensitive to inoculation was root exudation. In the absence of a microbial inoculant only 1% of assimilated label was exuded. Inoculation of the microcosms always caused an increase in exudation but the percentage exuded varied greatly, within the range of 3–34%.     

柿树炭疽菌侵染不同柿树种、品种和部位的细胞学特征

用柿树炭疽病菌Colletotrichumgloeosporioides的分生孢子制备孢子悬浮液,接种无核柿、野柿、冬柿和浙江柿的新梢、叶柄和叶片,并观察致病性、附着胞形成和侵染特性。柿树炭疽菌可以侵染无核柿枝条和叶柄以及野柿枝条,但不侵染无核柿叶片、野柿叶柄和叶片,也不侵染冬柿和浙江柿枝条、叶柄和叶片。室内接种试验与田间自然发病结果一致。柿树炭疽菌在不同柿树表面均能形成附着胞,附着胞产生在寄主表皮背斜细胞壁间结合处(JACWs)或近结合处的百分率达81%~93%。接种12h后,不同柿树表面都有附着胞形成;36h后,无核柿枝条、叶柄中有侵染菌丝存在;48h后,无核柿枝条、叶柄中观察到膨大初生菌丝和较细次生菌丝,初生菌丝可扩展到相邻细胞中,而野柿枝条中仅观察到侵染菌丝;60h后,野柿枝条中也观察到膨大的初生菌丝和较细的次生菌丝,但初生菌丝仅局限在最初侵染的细胞中,无核柿枝条和叶柄以及野柿枝条中都有分枝的次生菌丝在细胞内、细胞间或相邻的细胞中扩展;直到接种90h后,在冬柿和浙江柿上都未观察到侵染菌丝的形成。结果表明,柿树炭疽菌在不同柿树种和品种上侵染菌丝的形成和扩展方式可能是其寄主专化性(或致病性)差异的重要机制之一。     

Observations on the Taiwanese Strain of Leucocytozoon caulleryi (Haemosporina) in Chickens

ABSTRACT. The Taiwanese strain of Leucocytozoon caulleryi was isolated from an infected chicken in Taipei, Taiwan, and established in chickens and biting midges Culicoides arakawae from Japan. Sporogony of the strain in C. arakawae was completed on day 3 after the infective blood meals at 25°C. Sporozoites isolated from the salivary glands of C. arakawae on days 3 or 4 after feeding caused infection in all the chickens inoculated. The strain showed high pathogenicity for chickens. Mortality of chickens rose with an increase in the number of sporozoites inoculated. The prepatent period for chickens inoculated with sporozoites was 14 days. Parasites appeared in the peripheral blood of chickens on day 15 and disappeared on day 26 after sporozoite inoculation. Soluble antigens were found in the sera of chickens infected with the strain between 10 and 17 days after inoculation, and homologous antibodies appeared after 17 days. Antigens prepared from sera, schizonts, merozoites, and gametocytes of the Taiwanese strain reacted with the sera of chickens infected witt the same strain or the strain isolated in Japan. The chickens that recovered from a primary infection with the Taiwanese strain demonstrated complete resistance to reinfection with the same strain or the strain isolated in Japan.     

Observations on the Taiwanese strain of Leucocytozoon caulleryi (Haemosporina) in chickens

The Taiwanese strain of Leucocytozoon caulleryi was isolated from an infected chicken in Taipei, Taiwan, and established in chickens and biting midges Culicoides arakawae from Japan. Sporogony of the strain in C. arakawae was completed on day 3 after the infective blood meals at 25 degrees C. Sporozoites isolated from the salivary glands of C. arakawae on days 3 or 4 after feeding caused infection in all the chickens inoculated. The strain showed high pathogenicity for chickens. Mortality of chickens rose with an increase in the number of sporozoites inoculated. The prepatent period for chickens inoculated with sporozoites was 14 days. Parasites appeared in the peripheral blood of chickens on day 15 and disappeared on day 26 after sporozoite inoculation. Soluble antigens were found in the sera of chickens infected with the strain between 10 and 17 days after inoculation, and homologous antibodies appeared after 17 days. Antigens prepared from sera, schizonts, merozoites, and gametocytes of the Taiwanese strain reacted with the sera of chickens infected with the same strain or the strain isolated in Japan. The chickens that recovered from a primary infection with the Taiwanese strain demonstrated complete resistance to reinfection with the same strain or the the strain isolated in Japan.     

A comparative study on the uptake of ascorbic acid by the iris-ciliary body of the rabbit, guinea pig and rat

1. The uptake of 14C-ascorbic acid by the iris-ciliary body in vitro was examined in the rabbit, guinea pig and rat. 2. It was observed that iris-ciliary body from the rabbit and guinea pig, but not the rat, accumulated 14C-ascorbate to levels exceeding that in the bathing medium. 3. In all three species, the uptake of 14C-ascorbate was diminished by cold temperature; the degree of uptake at 0 degrees C was similar in the rabbit, guinea pig and rat iris-ciliary body. 4. Chromatographic examination of the 14C accumulated by the rabbit and guinea pig tissue demonstrated that the label remains almost exclusively as 14C-ascorbate.     

Persistent colonization and transient suppression of DTH responses in an estrogen-dependent vaginal candidosis murine model

Recurrence of vaginal candidosis in women of childbearing age has been attributed to several predisposing factors including the presence of significant amounts of estrogen in the reproductive tract. In this study, the effect of estrogen on the level of C. albicans colonization, persistence of infection and suppression of DTH responses was investigated in an estrogen-dependent vaginal candidosis murine model. Mice were first injected subcutaneously with 0.5 mg of estradiol valerate 72 hours prior to C. albicans intravaginal inoculation and at weekly intervals thereafter for a period of up to 4 weeks; the inoculum consisted of 2 x 10(7) stationary-phase C. albicans blastoconidia in a volume of 20 microl. C. albicans colonization was evaluated in the spleen, liver, kidney, small intestine and reproductive tract of estrogen-treated and control mice 72 hours following inoculation, DTH responses were evaluated 2 and 5 weeks following primary inoculation and persistence of infection was evaluated at days 2, 3, 4, 8, 12, 19 and 26 post inoculation. Estrogen-treated mice exhibited higher levels of C. albicans colonization compared with control mice; this was most evident in the small intestine and reproductive tract. Estrogen treatment resulted in pronounced suppression of C. albicans-specific DTH responses; in that average footpad swelling was 4.7 mm in untreated mice compared with 2.3 mm in estrogen-treated mice. Long-term estrogen treatment resulted in the persistence of infection; in contrast, C. albicans infection resolved by day 8 post inoculation in untreated mice. DTH responses assayed 5 weeks post primary inoculation in treated mice were on average 4.1 mm, this was similar to that observed in untreated mice tested for DTH response 2 and 5 weeks post primary inoculation. These results suggest that, on the one hand, estrogen has an enhancing effect on C. albicans colonization and persistence of infection. On the other, estrogen seems to suppress DTH responses within the first 2 weeks post infection; persistence of infection under the influence of estrogen, however, seems to coexist with detectable systemic cell-mediated immunity.     

西藏高原天然长芒草地丛枝菌根真菌接种效应

采用草地均匀打孔方法,就草地土壤未消毒条件下接种丛枝菌根（AM）真菌对长芒草(Stipa bungeana)的侵染效应以及对植物生长、吸磷效率、土壤微生物区系等的影响进行研究.结果表明,1)接种处理、不接种处理的菌根效应存在着明显的差异,多数接种处理根围土壤AM真菌孢子密度、菌根侵染率和侵染强度显著提高,但对丛枝丰度的影响相对较低.2)接种后AM真菌孢子密度对菌根侵染率具有极显著影响(r=0.7679**);随菌根侵染率的增加,植株总干物重和吸磷总量均呈极显著提高,r值分别为0.7556**、0.8018**.3)与植株地上部相比,接种AM真菌对提高根系干物重、根系吸磷量和含磷量的促进作用相对较大.4)多数接种处理根际土壤酸性磷酸酶、碱性磷酸酶活性均呈一定程度的提高,根际土壤细菌数量显著增加,真菌、放线菌的数量变化则不甚明显.5)各接种处理对寄主植物的综合侵染效应在总体上呈Glomus mosseae+G. intraradices+Scutellospora calospora＞G. mosseae+G. aggregatum＞Glomus sp.＞G. mosseae＞G. mosseae+ G. etunicatum+G. intraradices+S. erythropa＞G. geosporum的趋势.     

14C]methylammonium transport by Frankia sp. strain CpI1

We describe an NH4+-specific transport system in the N2-fixing symbiotic actinomycete Frankia sp. strain CpI1. [14C]methylammonium was used as an NH4+ analog. No specific transport process was detected when cells were grown on high concentrations of NH4+. A transport system with a high affinity for CH3NH3+ was synthesized after 3 to 4 h of nitrogen starvation. Methylammonium transport was not significantly inhibited by a variety of amino acids, primary amines, and polyamines. Ammonium completely eliminated CH3NH3+ transport. The Km for CH3NH3+ transport was around 2 +/- 1.8 microM with a Vmax of 4 to 5 nmol/min per mg of protein. The electron transport inhibitors cyanide and azide eliminated uptake, as did the uncoupler carbonyl cyanide-m-chlorophenylhydrazone. The sulfydryl reagent p-chloromercuribenzoic acid and the heavy metal thallium also inhibited uptake, suggesting the presence of an NH4+-specific permease. Concentration of CH3NH3+ across the membrane was demonstrated by conducting uptakes at low temperature to slow the metabolism of CH3NH3+ by glutamine synthetase. At 7 degrees C most of the label was concentrated inside the cells in a form that could be chased from the cells by adding excess NH4+ to the medium. At 30 degrees C most of the label was present as an impermeant metabolite. Thin-layer chromatography of cell extracts confirmed that the radioactivity inside the cells was mainly in the form of CH3NH3+ at 7 degrees C but was present as an unidentified metabolite at 30 degrees C. These studies demonstrate that Frankia sp. strain CpI1 has a high-affinity NH4+ transport system that is synthesized in response to NH4+ starvation.     

Influenza virus infection of tracheal gland cells in culture.

Influenza virus-induced tracheobronchitis causes limited epithelial deciliation but markedly decreased mucociliary transport. This suggests that virus-induced alterations in airway mucus play a role in decreased mucociliary transport. Airway submucosal glands are a primary source of mucus. Therefore, we examined virus-gland cell interactions by exposing primary cultures of isolated feline tracheal gland cells to influenza A/Scotland/840/74 H3N2 virus for 1 h at a multiplicity of infection of 0.1. Virus production and release into the culture medium first occurred between 8 and 12 h postinfection and eventually reached a steady state that continued for at least 8 days. Virus which was produced and released by infected cells infected other monolayers, resulting in viral production similar to that after infection with stock virus. Hemadsorption assays conducted 24 h after infection demonstrated that most of the cells in a monolayer became infected. The infection was nonlytic according to cell morphology, trypan blue dye exclusion, and release of lactate dehydrogenase. Because lysis of a cell subpopulation could have been masked by subsequent cell division, we compared the uptake of [3H]thymidine by infected and control monolayers. There was no increase in uptake by infected monolayers. These results demonstrate that feline tracheal gland cells in primary culture undergo productive and nonlytic infection with influenza A virus. This model provides a unique system for the study of virus-gland interactions isolated from the influence of other tissues.     

Ribulose Bisphosphate Carboxylase Protein and Enzymes of CO2 Assimilation in Barley Infected by Powdery Mildew (Erysiphe graminis hordei)

Effects were examined of barley powdery mildew (Erysiphe graminis f. sp. hordei) on the major leaf protein, ribulose-l,5-bisphosphate carboxylase (RuBPCase), and other enzymes of CO₂ assimilation, phosphoenolpyruvate carboxylase (PEPcase) and malic enzymes, and enzymes associated with RuBPCase in the reductive pentose phosphate pathway. Activity of RuBPCase per unit fresh weight of leaf was inhibited by infection from the first sample, 3 days after inoculation, to the last sample, 24 days after inoculation, when healthy control leaves were visibly senescing. The inhibition occurred because the amount of RuBPCase protein (measured specifically by an immunological technique) was reduced from 6 days after inoculation and because activity per unit protein declined from 3 days until 21 days after inoculation, at which time there was little protein remaining. Activity of PEPcase per unit fresh weight of leaf was initially stimulated by infection but, thereafter, it was inhibited. Inhibition, like that also affecting malic enzymes (NAD) and (NADP), 3-phosphoglycerate kinase, and glyceraldehyde-3-phosphate dehydrogenases (NAD) and (NADP), was associated with a decline in amounts of total soluble minus RuBP Case protein per unit fresh weight of leaf. Reduced amounts of leaf protein may be associated with reduced nitrate uptake by roots and fungal demand for nitrogen in mildewed plants.