Early Stages Of Incubation Research Articles

The temperature-sensitive period (TSP) during incubation of broad-snouted caiman (Caiman latirostris) eggs

Abstract All crocodiles studied to date exhibit temperature-dependent sex determination. During the many weeks from egg laying to hatch there is a period of 10 to 15 d in the middle third of incubation (in the American alligator) during which the sex of the embryo is irreversibly fixed, referred to as the temperature-sensitive period or TSP. In this work we investigated the TSP in Caiman latirostris eggs incubated at female-inducing and male-inducing temperatures (29° C and 33° C respectively) by switching eggs from 29° C to 33° C and vice versa at timed interval throughout incubation. Compared to Alligator mississippiensis the duration of TSP was longer, and the onset of TSP was at an earlier stage of incubation.

Characterization of the transformations of lignocellulosic structures upon degradation in planted soil

Analytical pyrolysis (AP) as well as chemical analysis, ESR, FTIR and UV/VIS-spectroscopy has been used to characterize effects of modification of industrial lignins (hydrolysis lignin and kraft lignin) with silicon-containing oligomers on their transformation in soil planted with timothy grass ( Phleum pratense). Using Py-GC/MS it was shown that carbohydrate-originated admixtures of non-modified hydrolysis lignin were degraded preferentially during the first vegetation season (12 weeks), whereas the degradation of lignin moieties was developed during the second vegetation season (60 weeks of incubation). The modification of both hydrolysis and kraft lignins with Si-oligomers promotes degradation of lignin from the earlier stage of incubation in soil. After the first 12 weeks of incubation the G/S ratio in products from pyrolysis of residual Si-modified hydrolysis lignin has increased almost twice, whereas for non-modified hydrolysis lignin this ratio has not changed. At the same time, Si-modification prevented oxidation of lignin during the whole incubation duration: yields of CO 2 and carbonyl-containing compounds upon pyrolysis of residues of Si-modified hydrolysis lignin were lower in comparison with those for the residues of non-modified lignin. Simultaneously with degradation, condensation of the lignins residual structure occurred, moreover in Si-modified hydrolysis lignin up to a higher extent than for non-modified lignin. For non-modified kraft lignin an aromatization and condensation of the structure was observed at earlier incubation time in comparison with hydrolysis lignin, and the effect of Si-modification in this case is not as potent as it is observed for hydrolysis lignin. Py-GC/MS data were used to define relationships between the changes in chemical structure of lignins and numbers of microorganisms in the timothy grass rhizosphere. Significant positive correlations were found between the development of humus-degrading bacteria population and the relative abundance of carbon dioxide in the lignin pyrolysis products as well as between numbers of humus-degrading fungi population and relative abundances of guaiacol and syringol.

Embryonic developmental plasticity of the chick: Increased CO 2 during early stages of incubation changes the developmental trajectories during prenatal and postnatal growth

This study investigated the effect of non-ventilation of the incubator during the first 10 days of incubation on carbon dioxide (CO 2) concentrations in the incubator and its effects on the embryonic and post-hatch development of the chicken ( Gallus gallus). Two different incubation conditions were created, one incubator was kept at standard conditions, with adequate ventilation (V) and a second incubator was non-ventilated (NV) during the first ten days of incubation, allowing the CO 2 to rise. After the first 10 days, both incubations were continued under standard conditions. The experiment was repeated twice with different ages of the breeders (45 and 60 wks) which resulted in different CO 2 levels at ED10 (1.5 and 1%). The CO 2 concentration in the V incubators remained below 0.1% in these first 10 days. The eggs of the NV incubation showed higher pCO 2 levels in the air cell from ED10 until ED14 compared to the eggs of the V group. The NV embryos had significantly higher absolute and relative (to egg weight) body weights from ED10 until ED18, pointing to an accelerated embryonic growth. At internal pipping, the NV chick embryos had higher plasma corticosterone and T 3 levels and higher pCO 2 in the air cell. Chicks incubated under NV conditions hatched 10 h earlier in the first and 15 h earlier in the second experiment and the spread of hatch was narrower. During the post-hatch period, the NV chickens had a higher body weight compared to the V chickens. From these results, it is clear that higher levels of CO 2 during the first ten days of incubation have persistent (epigenetic) effects during the incubation and early post-hatch period.

Effect of resident microbiota on the solubilization of gold in soil from the Tomakin Park Gold Mine, New South Wales, Australia

The processes influencing the solubilization and observed mobility of Au in soil were studied using a combination of geochemical and microbiological techniques. In this study, we demonstrate for the first time that biotic processes mediated by the resident microbiota are likely to control the mobilization of Au in auriferous soils and other regolith materials. Microcosms with auriferous soils from the Tomakin Park Gold Mine in temperate south eastern New South Wales, Australia, were incubated under biologically active versus inactive (sterilized) conditions. The soils were incubated oxic and anoxic, unamended and Au pellet- or cycloheximide amended for 70 days in a 1:4 (w:v) aqueous slurry at 25 °C in the dark. In biologically active unamended Ah- and B-horizon microcosms up to 80 wt.% of total Au was detected in solution after 45 days of incubation. In biologically active Au pellet amended microcosms Au was liberated from the soil and also from added Au pellets. Scanning electron microscopy and nucleic acid staining combined with confocal stereo laser microscopy revealed the presence of bacterial biofilms on Au pellets incubated in the biologically active microcosms. The biologically inactive microcosms displayed no or significantly reduced Au solubilization. After 40–50 days of incubation Au was generally re-adsorbed to the solid soil fractions. The results of sequential extractions conducted with dried slurry samples collected from the biologically active Ah-horizon microcosms after 0, 10, 20, 30, 40, and 68 days of incubation indicated a continuous microscale solubilization and re-adsorption of Au. In samples taken after 40 days of incubation more than 80 wt.% of the Au was extracted from the operationally defined organic fraction, which appears to act as a final re-adsorption site for Au in the soil. In samples taken after 10 days of incubation from microcosms amended with 100 μg g −1 (d.w. soil) of Au as AuCl 4 − 95 wt.% of the Au was associated with the organic fraction. To establish a mechanistic link between Au dissolution and re-adsorption with the activity of the heterotrophic bacterial community, analysis of the community structure based on carbon utilization patterns using was conducted. The bacterial community structure changed from a carbohydrate- and polymer-utilizing to a carboxylic- and amino acid utilizing community concurrently with the change from Au solubilization to re-adsorption. The bacterial community in the early stages of incubation (0–30 days) apparently produced an excess of amino acids, which are known to form stable amino acid Au complexes. The bacterial community in the later stages of incubation (after 40–50 days) metabolized these Au complexing ligands and Au, which apparently became unstable in the solution, was re-adsorbed to the solid soil fractions.

Effect of Continuous Application of Shear Stress on Liver Tissue: Continuous Application of Appropriate Shear Stress Has Advantage in Protection of Liver Tissue

Rapid blood flow changes occur in the liver following a massive resection or in the grafted liver following transplantation, under which shear stress (SS) change induced by the flow change may determine the postoperative results. We observed changes in liver tissue structure and liver-specific function, and consequently assessed SS effect. The cultured liver tissue exposed to continuous application of moderate SS was shown to express and maintain a long-term liver-specific function. There was also evidence showing that destruction of the liver structure was inhibited. However, the cultured liver tissue not exposed to SS or exposed to high SS was shown to lose liver-specific function soon after expression. The liver structure was destroyed in the early stage of incubation. These results suggested that continuous application of appropriate SS has advantages over other types of stresses to protect liver tissue.

A secreted lipase encoded by LIP1 is necessary for efficient use of saturated triglyceride lipids in Fusarium graminearum

A triglyceride lipase gene LIP1 was identified in the genome of Fusarium graminearum strain PH-1. The predicted protein encoded by LIP1 contains 591 amino acid residues with a putative N-terminal signal peptide and shows 57 and 40-44 % identity to a Botrytis cinerea lipase and five Candida rugosa lipases, respectively. Yeast cells overexpressing LIP1 showed lipolytic activity against a broad range of triglyceride substrates. Northern blot analyses revealed that expression of LIP1 was activated in planta during the fungal infection process. LIP1 expression was strongly induced in minimal medium supplemented with wheatgerm oil, but only weakly induced by olive oil and triolein. In contrast, supplementation with other carbon sources, including glucose, sucrose, apple pectin and wheat cell-wall material, did not induce LIP1 expression. Saturated fatty acids were the strongest inducers for LIP1 expression and this induction was suppressed proportionally by the presence of the unsaturated fatty acid. To determine the potential function of LIP1, gene replacement was conducted on strain PH-1. When compared with wild-type PH-1, DeltaLIP1 mutants showed greatly reduced lipolytic activities at the early stage of incubation on minimal medium supplemented with either saturated or unsaturated lipid as the substrate, indicating that LIP1 encodes a secreted lipase for exogenous lipid hydrolysis. Moreover, the DeltaLIP1 mutants exhibited growth deficiency on both liquid and solid minimal media supplemented with the saturated triglyceride tristearin as the sole carbon source, suggesting that LIP1 is required for utilization of this substance. Despite these differences, no variation in disease symptoms between the DeltaLIP1 mutants and the wild-type strain was observed on susceptible cereal hosts.

Flocculating activity of cross-linked poly-γ-glutamic acid against bentonite and Escherichia coli suspension pretreated with FeCl 3 and its interaction with Fe 3+

Cross-linked poly-gamma-glutamic acid (C-L gamma-PGA) at 5 microg/ml flocculated bentonite suspension pretreated with polyaluminum chloride (PAC) at 2 microg/ml Al3+-PAC to a transparency of approximately 30% after 30 min and more than 90% after 4 h, while Al3+ concentration in the upper phase of the suspension decreased with incubation time. When pretreated with FeCl3 at 16 microg/ml Fe3+-FeCl3, similar results were obtained. In the case of Escherichia coli suspension, the combination of C-L gamma-PGA and FeCl3 demonstrated a more marked flocculating activity with a satisfactory transparency occurring after 30 min of treatment, accompanied by a decrease in residual Fe3+ concentration. In the above two suspensions pretreated with FeCl3, small visible floats appeared in the early stage of incubation. These floats were found to be due to the direct interaction between FeCl3 and C-L gamma-PGA, indicating the formation of a water-insoluble complex. After allowing the suspension to stand for a long time, elemental analysis and inductively coupled plasma spectroscopy of the precipitates produced suggested that not only the complex was formed due to the interaction between Fe3+ in FeCl3 and COO- in the C-L gamma-PGA molecule, but also Fe2O3 and Fe(OH)3 might be entrapped in this complex. This could be applied to scavenge metal ions including Fe3+ from polluted water.

The effect of ursodeoxycholic acid on glycochenodeoxycholic acid-induced apoptosis in rat hepatocytes

Ursodeoxycholic acid (UDCA) has been widely used for treating cholestatic liver diseases. However, in a recent review of clinical trial articles, its therapeutic benefits were not proven. Therefore, we investigated whether UDCA prevents or potentiates glycochenodeoxycholic acid (GCDCA)-induced apoptosis in isolated rat hepatocytes. Hepatocellular cytotoxicity was assessed by lactate dehydrogenase (LDH) release, and apoptosis evaluated by DNA fragmentation, caspase activities, release of cytochrome C from mitochondria, and mitochondrial membrane potential change (Δ ψ). When hepatocytes were co-incubated with GCDCA and UDCA for a short time (2–6 h), GCDCA-induced LDH release was significantly reduced, while prolonged co-incubation (12–20 h) increased it. Similarly, the same co-incubation for a short time resulted in the inhibition of caspase activities and cytochrome C release, while prolonged incubation enhanced them compared with the incubation with GCDCA alone. Furthermore, UDCA significantly promoted the GCDCA-induced Δ ψ decline after 4 h of incubation. These results demonstrated that UDCA reduced GCDCA-induced apoptosis in short incubation, but potentiated it in prolonged incubation. Based on these, we propose a hypothesis that induction of Δ ψ decrease from earlier stage of incubation may be responsible for the aggravation of GCDCA-induced apoptosis in long-term exposure, and would like to raise caution about clinical long-term use of UDCA.

Ex ovo electroporation for gene transfer into older chicken embryos

In ovo electroporation is an excellent method to ectopically induce or inhibit gene expression in chicken embryos and to study the in vivo function of genes during embryonic development. However, the application of electroporation in ovo to date is limited to an early stage of incubation (< stage 20). In older embryos (> stage 22), the vitelline and allantoic vessels have developed extensively and the in ovo manipulation of the embryo becomes exceedingly difficult. Therefore, in this study, we validate an ex ovo electroporation system, by which the time for performing electroporation can be extended up to at least day 7 of incubation. The application of this method will help to study gene function and regulation at later stages of development in the living chicken embryo.

Actividad enzimática extracelular y serotipo en cepas de Cryptococcus neoformans de pacientes con sida en Brasil

One hundred and fifty-one Cryptococcus neoformans strains isolated from AIDS patients in Brazil and maintained in the Adolfo Lutz Institute (São Paulo, Brazil) were tested for phospholipase, protease and other extracellular enzymatic activities and their serotypes determined. Production of extracellular phospholipase and protease was tested by the agar plate methods. Determination of extracellular enzyme profile of the strains was performed by using the API-ZYM kit system, which can test 19 different enzymes. The serotypes were determined by cell agglutination using the Crypto-check method. Among the 151 strains, 147 were identified as serotype A and four strains were serotype AD. Production of extracellular phospholipase and protease was extensive and observable at early stages of incubation. All of the tested strains were positive for the production of both enzymes. In the API-ZYM tests, more than 90 % of the 151 tested strains were positive for esterase C4 (No. 3), esterase lipase C8 (No. 4), leucine arylamidase (No. 6), phosphatase acid (No. 11), naphtol-AS-BI-phosphohydrolase (No. 12), alpha-glucosidase (No. 16) and beta-glucosidase (No. 17). Differences in enzymatic activities between the Brazilian strains and strains isolated in other countries were observed. The phospholipase, protease and other enzyme activities may play a role in host tissue invasion by C. neoformans.

Decrease in molecular weight of photosynthetic products of marine phytoplankton during early diagenesis

Changes in the size and neutral aldose (NAld) composition of phytoplankton photosynthetic products during the early diagenetic process were experimentally examined using 13C as a tracer. Most (94.7%) of the photosynthetically produced (P−) organic carbon (OC) was found to be particulate organic carbon (POC) after a 12‐h light incubation. An increase in the concentration of P‐dissolved organic carbon (DOC) was found after the shift to the dark incubation, probably due to a leakage of cellular constituents. An increase in the concentration of P‐DOC was mainly due to an increase in the high molecular weight (HMW: ≫10 kDa) fraction that reached its maximum concentration on day 3 and then declined at a relatively high rate. The change in the concentration of the low molecular weight (LMW: ≪10 kDa) DOC fraction was less marked than that in the HMW fraction, and the rate of decrease was much slower, indicating a more biorefractory nature of P‐LMW DOC. P‐dissolved carbohydrates (DCHO) accounted for 38% and 50% in P‐HMW DOC and P‐LMW DOC, respectively, after a 12‐h light incubation. The concentration of P‐LMW DCHO showed a rapid decrease in the early stage of the dark incubation, whereas the concomitant increase in the concentration of P‐LMW dissolved noncarbohydrate (DnonCHO) was noticed. The decrease in the contribution of CHO was noticed both in P‐POC and P‐HMW DOC fractions, but the decline rates were slower than that in P‐LMW DOC fraction. On day 60, the remaining P‐OC accounted for 4.6% of photosynthetic material originally produced. The distribution of the size fractions of the remaining P‐OC on day 60 (POC, 14%; HMW DOC, 22%; LMW DOC, 64%) indicates that phytoplankton photosynthetic products were rapidly degraded to the less bioreactive LMW DOM during early diagenesis. The present results indicate that the annual global ocean production rate of semilabile DOC with lifetimes exceeding 2 months is 1.91 PgC yr−1.

The process of sulfide oxidation in some acid sulfate soil materials

The process of sulfide oxidation in acid sulfate soils (ASS) is complex, involving the formation of numerous oxidation products. In this study the sulfide oxidation process was examined in 2 ASS materials over a period of 36 days using laboratory incubation experiments. Both ASS materials experienced substantial sulfide oxidation and acidification during incubation. The oxidation of pyrite was the primary cause of acidification in these ASS materials. Although a decrease in magnetic susceptibility (χ) over the initial 4 days of incubation suggested the rapid oxidation of ferromagnetic iron monosulfide greigite (Fe3S4), the total acid volatile sulfur (SAV) fraction increased in concentration by an order of magnitude over the initial 8 days of incubation. Oxygen (O2) concentration profiles indicated the presence of anoxic conditions in the centre of the incubating materials even after 16 days of exposure to the atmosphere enabling SAV formation to occur. The oxidation of the SAV fraction did not result in substantial acidification. A large proportion of the water-soluble iron released by sulfide oxidation was precipitated as iron oxides and hydroxides. Sulfate (SO42–) was the dominant sulfur species produced from sulfide oxidation in both ASS materials, although water-soluble SO42– was a poor indicator of the extent of sulfide oxidation. The sulfoxyanion intermediates, thiosulfate (S2O32–) and tetrathionate (S4O62–), were detected only in the early stages of incubation, with minimal amounts being detected after the initial 4 days. The relative abundance of these 2 intermediate sulfur species appeared to be dependent on the soil pH, with S4O62– dominating S2O32– in the more acidic ASS material (i.e. pH &lt;6) as has been observed in previous studies. The diminishing presence of sulfoxyanion intermediates as oxidation progressed was indicative that ferric ion (Fe3+) and bacterial catalysis were driving the oxidation processes. While these sulfoxyanion intermediates only constituted a small percentage of the reduced inorganic sulfur (RIS) fraction, they accounted for up to 9.3% of the total soluble sulfur fraction. Elemental sulfur (S0) was not an important sulfide oxidation product in the ASS materials examined in this study.

The Response of Escherichia coli, Bacillus subtilis, and Burkholderia cepacia WZ1 to Oxidative Stress of Exposure to Quinclorac

The activity response of the antioxidant enzymes superoxide dismutase, catalase, ATP enzyme activities of Escherichia coli (G−), Bacillus subtilis (G+), and Burkholderia cepacia WZ1 (G−) following exposure to quinclorac was investigated. The bacterial strains were treated with the different concentrations of quinclorac (1.65, 16.5, 33.0, 165.0, 330.0, and 500.0 µg L−1). Results obtained indicated that SOD and CAT activities of these bacteria were induced positively and obviously by quinclorac, especially to Gram-positive (G+) bacteria treated by lower than 330 µg L−1 of quinclorac. The inhibition of ATPase in E. coli K12, B. subtilis, and B. cepacia WZ1 appeared stronger with the increase of quinclorac concentration, showing a striking dose–response relationship, which can, therefore, be used as an available bioindicator for quinclorac pollution. The concentration of quinclorac applied in this research had significant effects on these three bacteria at the early stage of incubation, but none of which was persistent. Native polyacrylamide gel electrophoresis and activity staining of SOD revealed that quinclorac had effects on isoforms of E.coli and B. subtilis, and on the staining intensities of the isoforms of B. cepacia WZ1. When E. coli K12 was incubated with 330 µg L−1 of quinclorac, the upper band of the isoforms of SOD tended to become slightly more apparent at 1 h after the quinclorac treatment, but the staining activity was slightly reduced after the prolonged treatment of quinclorac. No such changes of the isoforms of B. cepacia WZ1 was observed.

Effect of straws from Bt-transgenic rice on selected biological activities in water-flooded soil

The biochemical properties of soil have often been described as early and sensitive indicators of ecological changes in both natural soil and agroecosystem. In the current study, the impacts of the amendment of Bt-transgenic rice (KMD) straw on biological activities in water-flooded soil were investigated under laboratory conditions and compared with non-transgenic rice (Xiushui 11) straw. The results showed that there were some differences in protease, neutral phosphatase and cellulase activities between soil amended with Bt-transgenic rice straw and non-transgenic rice straw at the early stage of incubation, and none of these differences were persistent. However, differences in dehydrogenase activity, methanogenesis, hydrogen production and anaerobic respiration between soil supplemented with Bt-transgenic rice straw and non-transgenic rice straw were persistent over the course of incubation. Dehydrogenase activity, methanogenesis and anaerobic respiration were considerably lower from sample days 7 to 56, but higher after day 56 in soil amended with Bt-transgenic rice straw. In comparison, the H 2-production in soil containing Bt-transgenic rice straw was significantly lower after day 56. The results demonstrated that the amendment of the Bt-transgenic rice straw altered some important biological properties in water-flooded soil, indicating a shift in microbial populations or a change in the metabolic abilities of the microbial community as a result of substrate availability in soil.

Bt-transgenic rice straw affects the culturable microbiota and dehydrogenase and phosphatase activities in a flooded paddy soil

There have been few investigations of the possible effects of genetically engineered plants on the microbiota and enzyme activities in flooded soil. We studied the influence of the transgenic rice KeMingDao (KMD) straw on the culturable microbiota and enzymatic activities in a flooded paddy soil under laboratory conditions. KMD contained a synthetic cry1Ab gene from Bacillus thuringiensis under the control of a maize ubiquitin promoter and linked in tandem with the gusA and hpt genes. The results showed that there were only some occasional significant differences ( P<0.05) in the number of Colony forming units of aerobic bacteria, actinomycetes and fungi and in the number of anaerobic fermentative bacteria, denitrifying bacteria, hydrogen-producing acetogenic bacteria, and methanogenic bacteria between the paddy soil amended with Bt-transgenic rice straw and with the non-Bt parental rice straw during the early stages of incubation. From d14 to d84 there were significant increases ( P<0.05) in soil dehydrogenase and soil neutral phosphatase activity in soils amended with rice straw compared to soil without added straw. The dehydrogenase activity was significantly greatly (almost 1.95-fold) in soil amended with Bt-transgenic straw from d7 to d14 but from d21 to d49 there was significantly greater activity (about 1.47-fold) in the soil amended with non-Bt-straw. There were no apparent differences between the activity of soil neutral phosphatase in the soils to which non-Bt-straw and Bt-straw had been added. However, both soils to which rice straws were added demonstrated significant differences in the number of microorganisms except for aerobic bacteria and enzymatic activities with respect to the control soil throughout the incubation. The above results indicated that the Bt-straw from KMD transgenic rice is not toxic to a variety of culturable microorganisms in the studied flooded paddy soil.

Dephosphorylation of p53 during cell death by N-α-tosyl- l-phenylalanyl chloromethyl ketone

The apoptotic function of N-α-tosyl- l-phenylalanyl chloromethyl ketone (TPCK) was investigated in cultured human colorectal carcinoma cells (HCT116). TPCK-induced apoptosis was shown to be p53-dependent in HCT116 cells during the early stage of incubation. The function of p53 was required for TPCK-induced activation of caspase-3 and caspase-7. TPCK promoted dephosphorylation of p53 on serine residues at 6, 9, 46, 376, and 378 in parallel with the activation of p53 transcriptional activity. HCT116 p53−/− cells expressing p53 mutant, in which serine residues at 6, 9, 46, 376, and 378 were replaced by aspartic acids, were resistant to TPCK-induced apoptosis suggesting the requirement of dephosphorylation of p53 on serine residues during TPCK-induced apoptosis.

Vibration analysis on incubating eggs and its relation to embryonic development.

Coucke (1998) was the first to use acoustic resonance analysis to monitor embryo development in chicken eggs. He remarked that at around 100 hours of incubation, the course of the resonant frequency and damping changed abruptly in the case of fertile eggs. He also showed that these changes were related to a physiologic event during early embryonic development. The objective of our study is to monitor the course of the vibration parameters during the early incubation of chicken eggs and to relate these changes to egg and embryo characteristics. A total of 72 Hybro eggs were incubated vertically in a small incubator at standard conditions. Several egg parameters were measured before incubation. During the early stages of incubation the vibration behavior of these eggs was monitored. The time at which the damping of the vibration suddenly changed, the diameter of the eggs and their interaction were found to be significant explanatory variables in order to predict hatching time. A correlation coefficient r of 0.72 was obtained.

Grassland Passerine Nest Predators Near Pasture Edges Identified on Videotape

Abstract Fragmentation of grassland habitat may increase predation rates on grassland passerine nests and contribute to population decline of several species. Studies that simultaneously document the nest predator community and associate predator species with edges created by fragmentation have not been conducted for grassland habitats. The purpose of our study was to evaluate the effects of using miniature video camera systems to document predation events, identify grassland passerine nest predators in grazed pastures, and determine whether predation patterns of nest predators known to prefer wooded edges differed from those of other nest predators. In 1998–2000, we deployed cameras at 89 nests of Savannah Sparrows (Passerculus sandwichensis), Grasshopper Sparrows (Ammodramus savannarum), Song Sparrows (Melospiza melodia), meadowlarks (Sturnellaspp.), and Bobolinks (Dolichonyx oryzivorus) in southwestern Wisconsin pastures 16–169 ha in size. Abandonment rates were higher for nests with cameras than for nests without cameras (P = 0.04). Trampling rates did not differ between nests with and without cameras. There was limited evidence of differences in predation rates between nests with and without cameras. Predation rate was high in the early incubation stage. Grassland passerine nests were depredated by at least 11 different species in that system, and the predator community differed from those documented in similar studies in other regions. Raccoon (Procyon lotor), thirteen-lined ground squirrel (Spermophilus tridecemlineatus), and snakes (Thamnophisspp. and Elaphespp.) were most common. Over one-third of documented predation events were caused by species that prefer wooded edges. Those species usually depredated nests located closer to wooded edges than to any other type of edge, but there was no evidence that those species restricted their movements to depredate nests within a certain distance from wooded areas in the landscape compared to grassland specialist species (P = 0.28). Predators known to prefer wooded edges traveled up to 190 m into pastures and up to 150 m from wooded areas. Effects of edge predators in pastures are likely to extend beyond the 50 m suggested by other grassland passerine studies.

Direct interaction of the Golgi membrane with the endoplasmic reticulum membrane caused by nordihydroguaiaretic acid

Nordihydroguaiaretic acid (NDGA), an inhibitor of lipoxygenase, blocks protein transport from the endoplasmic reticulum (ER) to the Golgi complex and induces the redistribution of Golgi proteins into the ER. We investigated characteristics of NDGA-induced retrograde movement of the Golgi proteins to the ER. At an early stage of incubation of cells with NDGA, the Golgi complex formed convoluted membrane aggregates. Electron microscopy revealed that these aggregates directly interact en bloc with the ER membrane. The direct interaction and subsequent incorporation of the Golgi proteins into the ER were found to be temperature-dependent. The protein of ER–Golgi intermediate compartment (ERGIC), ERGIC53, was rapidly accumulated in the Golgi upon treatment with NDGA. This accumulation was significantly inhibited by low temperature at 15 °C. Under the condition, the redistribution of the Golgi proteins into the ER as well as the direct interaction between the ER and the Golgi by NDGA were also inhibited, suggesting an important role of the ERGIC in the retrograde movement. In contrast, the low temperature did not inhibit formation of the Golgi aggregates by NDGA. Taken together, these results suggest that NDGA causes the redistribution of the Golgi proteins into the ER through the direct connections between the Golgi, the ERGIC, and the ER.

Comparative Metabolism of Organophosphorus Pesticides in Water-Sediment Systems

The aerobic aquatic soil metabolism of three 14C-labeled organophosphorus pesticides was examined in French lake water-sediment systems to estimate factors controlling their behavior in the natural aquatic environment. The more hydrophobic tolclofos-methyl and butamifos rapidly distributed between the aqueous and sediment phases even in the early stage of incubation, while partition of cyanophos to the sediment was found to be more gradual. The three pesticides were degraded in the water-sediment systems with half-lives of 8.8 to 24.5 days. Tolclofos-methyl and cyanophos commonly underwent cleavage of the P-O-methyl and P-O-aryl linkages the latter with a stepwise hydration of the cyano group, while butamifos was degraded to many unknown compounds each with less than 1.4% of the applied radioactivity. The evaporative loss of tolclofosmethyl and butamifos possibly due to azeotropic co-distillation was observed. The behavior of pesticides in the water-sediment system was considered to be mainly controlled by the balance among partition, degradation and evaporative processes, at least in part due to their chemical structures and physico-chemical properties.