Variations in bacterial communities in laboratory-scale and big bale silos assessed by fermentation products, colony counts and denaturing gradient gel electrophoresis profiles

Aims: To assess the variation in bacterial communities in laboratory‐scale and big bale silos. Methods and Results: Wilted Italian ryegrass (628 g dry matter kg^?1) was ensiled in vacuum‐packed plastic pouches and big bales. Silos were opened after 3 months, and the fermentation products, colony counts and denaturing gradient gel electrophoresis (DGGE) profiles were determined. Eight samples were collected separately from a big bale, while one representative sample was taken from a plastic pouch. Significant variation was found between big bales in dry matter, ethanol, lactic acid, acetic acid and ammonia‐N contents. No differences were shown between plastic pouches and big bales, except that more ethanol was produced in the former air‐tight silos. Plastic pouches could resemble a specific silo and outer sampling sites of big bales based on fermentation products and DGGE profiles respectively. Conclusions: Considerable variation in fermentation products may exist between big bale silos. Plastic pouches can serve as a model of big bale silos, although they do not provide information on the heterogeneity within and between bales. Significance and Impact of the Study: Assessment of bacterial communities associated with ensiling can differ according to the criteria of fermentation products, colony counts and DGGE profiles.     

An economical system for liquid scintillation counting

Small glass shell vials (12 × 35 mm minivials), containing 2.0 ml of a dioxane-based scintillation solution plus a ¹⁴C-labeled sample, were placed in a conventional glass, 20-ml count vial and assayed in a scintillation spectrometer. Statistical comparison of counts recorded from ¹⁴C samples prepared both in the minivial system and conventional 20-ml count vials indicated that the two systems were equivalent with sample volumes of 10 and 100 μliters (1600-cpm solution) and 10 μliters (60-cpm solution). Conventional 20-ml glass or plastic count vials were both acceptable as containers for the minivials.There were no significant differences in the counts from samples in minivials placed on-center and off-center in the container vial. Cost per sample was reduced from 24.8 cents (conventional glass vials) to 4.7 cents (minivial system).     

Protection of histones isolated from elastase-treated mouse epidermis

Small glass shell vials (12 × 35 mm minivials), containing 2.0 ml of a dioxane-based scintillation solution plus a ¹⁴C-labeled sample, were placed in a conventional glass, 20-ml count vial and assayed in a scintillation spectrometer. Statistical comparison of counts recorded from ¹⁴C samples prepared both in the minivial system and conventional 20-ml count vials indicated that the two systems were equivalent with sample volumes of 10 and 100 μliters (1600-cpm solution) and 10 μliters (60-cpm solution). Conventional 20-ml glass or plastic count vials were both acceptable as containers for the minivials.There were no significant differences in the counts from samples in minivials placed on-center and off-center in the container vial. Cost per sample was reduced from 24.8 cents (conventional glass vials) to 4.7 cents (minivial system).     

The biosynthesis of the male housefly accessory secretion and its fate in the mated female

Autoradiographic studies of ejaculatory ducts from male houseflies, Musca domestica, previously injected with either tritiated arginine, lysine, or histidine showed that only arginine and lysine were incorporated into the stored accessory secretion. Scintillation spectrophotometry indicated that the amount of [³H] arginine incorporated into the duct correlated with the number of times the male had previously copulated. Cycloheximide and actinomycin D were effective in inhibiting the uptake of [³H] arginine in the ejaculatory ducts of newly emerged males, but only cycloheximide was an effective inhibitor in older males that had mated repeatedly. Autoradiography and electron microscopy showed that during mating the accessory secretion was transferred to the vaginal pouches of the female and that within 10 min after mating began, it was penetrating the intimal lining of the pouches. Cytolysis of many of the cells of these pouches was correlated to the transfer of the secretion during mating. This transfer of the secretion apparently terminated about 40 min after copulation began, although mating usually continued for an additional 10 to 20 min. The amount of ³H-labelled material in the haemolymph of the females increased until the completion of mating and then decreased about 60 per cent after 8 hr.     

Production of Soy Sauce Koji Mold Spore Inoculum in Plastic Bags

An innovation is described for producing soy sauce koji mold spore inoculum by using inexpensive autoclavable plastic bags and reuseable plastic enclosures to make culture vessels. After growth, the spore mass could be dried and packaged in the same bag after removing the enclosure. Broken rice was used as the substrate for mold cultivation. Viable spore counts of 10⁹ spores per g were obtained under optimal conditions. After drying at 50°C for 6 h, the moisture content of the spore mass decreased from 35.22 to 6.32% with no significant effect on spore viability. The dry spores could be stored in the refrigerator or at room temperature for at least 3 months.     

Cultivation of mammalian cells in heat-sealable pouches that are permeable to carbon dioxide

Petri plates, 96-well plates, and other unsealed culture vessels are the chief cause of air-borne contamination of cell cultures. In this study, heat-sealable plastic pouches that are permeable to CO2 and other gases are used as a means to avoid contamination. Several applications of heat-sealable pouches are described. First, petri plates can simply be sealed in a wide variety of plastic films that are permeable to CO2. Second, a few CO2-permeable plastic films can be used directly as substrata for mammalian cell growth and can also be cut with a simple hole punch for the isolation of clones. Third, one can grow cells in chemically sterilized carbonic acid solutions and thereby avoid the use of a CO2 incubator entirely.     

Effect of Handling Procedures on the Post-process Contamination of Retort Pouches

The effect of handling flexible retort pouches has been studied in relation to their integrity and resistance to post-process contamination ('leaker spoilage'). Tests were made using a pilot-plant processing line on which pouches were filled with broth, sealed, heat-processed and subjected to three post-process handling treatments. Using Enterobacter aerogenes as an indicator organism, it was shown initially that rough instead of careful handling during loading of the retort increased the proportion of punctured pouches from 0.06 to 0.27%. The effect of post-process handling procedures on leaker spoilage was studied using pouches deliberately punctured with a needle of 100 μm diameter. When these pouches were cooled in tap water, unloaded manually from the retort and stored wet, the incidence of post-process contamination was 90%. With similar pouches which were dried immediately after manual unloading and stored dry, the contamination rate was only 10%, whereas cooling in chlorinated water and drying before manual unloading reduced the contamination rate of punctured pouches to less than 1%. It was concluded that manual handling of dry pouches presents an acceptable alternative to complete mechanical handling of freshly heat-processed pouches, which was proposed in a Code of Practice for retort pouches formulated in 1971.     

Cheek pouch capacities and loading rates of heteromyid rodents

Rodents of the family Heteromyidae are proficient gatherers and hoarders of seeds. A major component of their adaptive specialization for harvesting and transporting seeds is their spacious, fur-lined cheek pouches. Precise measurements of cheek pouch capacities are essential if ecologists are to understand the foraging ecology, possible constraints on locomotion patterns, and competitive relationships of heteromyid rodents. To measure the size of these cheek pouches and the rate at which animals load seeds into their pouches during seed harvest, we attracted 56 individuals representing ten species of heteromyid rodents to bait stations in the field and allowed them to fill their cheek pouches with seeds several times while we observed and timed the events with the aid of night-vision equipment. The largest load taken by each individual was used as an estimate of its cheek pouch capacity. At the end of observations, each subject was captured and its mass and other data gathered. The allometric relationship between cheek pouch capacity and body mass for ten species of heteromyids was significant [pouch capacity (ml) = 0.148 body mass (g)^0.992, r ²=0.91, P<0.0001]. The regression coefficient is ≈1.0, which indicates that the volume of the cheek pouches scales in direct proportion to body size. When the data were subdivided into quadrupeds (Perognathus and Chaetodipus) and bipeds (Dipodomys) (n=5 for each), the relationships between pouch capacity and body mass were significant, but the two regressions were not significantly different from each other. When all loads (full and partial) were considered, subjects filled their cheek pouches an average of 93 ± 10% of pouch capacity (n=185). Cheek pouch capacities from published studies of artificially filled pouches of heteromyids in the laboratory averaged about 40% below the field measurements obtained here. The allometric relationship between mean loading rate and body mass was also significant [seeds/s=1.067 bodymass (g)^0.830, r ²=0.85,P=0.0011), but when quadrupeds and bipeds were considered separately, the relationships were not significant. Seed densities and bulk densities were used to calculate packing coefficients for seed species, which, when used in conjunction with the allometric relationship between cheek pouch capacity and body size, can be used to estimate the maximum load carried by a heteromyid. Except for the very largest kangaroo rat species, a full pouch load of Indian ricegrass seeds represents less than the daily energy requirements of an active heteromyid. Received: 3 March 1997 / Accepted: 15 July 1997     

Prediction of citation counts for clinical articles at two years using data available within three weeks of publication: retrospective cohort study

Objective To determine if citation counts at two years could be predicted for clinical articles that pass basic criteria for critical appraisal using data within three weeks of publication from external sources and an online article rating service.Design Retrospective cohort study.Setting Online rating service, Canada.Participants 1274 articles from 105 journals published from January to June 2005, randomly divided into a 60:40 split to provide derivation and validation datasets.Main outcome measures 20 article and journal features, including ratings of clinical relevance and newsworthiness, routinely collected by the McMaster online rating of evidence system, compared with citation counts at two years.Results The derivation analysis showed that the regression equation accounted for 60% of the variation (R²=0.60, 95% confidence interval 0.538 to 0.629). This model applied to the validation dataset gave a similar prediction (R²=0.56, 0.476 to 0.596, shrinkage 0.04; shrinkage measures how well the derived equation matches data from the validation dataset). Cited articles in the top half and top third were predicted with 83% and 61% sensitivity and 72% and 82% specificity. Higher citations were predicted by indexing in numerous databases; number of authors; abstraction in synoptic journals; clinical relevance scores; number of cited references; and original, multicentred, and therapy articles from journals with a greater proportion of articles abstracted.Conclusion Citation counts can be reliably predicted at two years using data within three weeks of publication.     

Lactic acid is absorbed from the small intestine of sheep

A series of experiments was conducted in vivo on anaesthetized sheep to explore the hypothesis that lactic acid is absorbed from the small intestine of sheep. Test solutions varying in lactic acid concentration, pH, osmolarity, and with fixed physiological concentrations of volatile fatty acids (VFAs), K+, Na+, NH4 +, Cl-, and PO4 (-3), were separately introduced into clean, surgically sealed pouches. Studies were undertaken in 27 sheep, each with three pouches in the middle of the duodenum, jejunum, and ileum. Samples were taken at 15-minute intervals for 60 minutes to determine the absorption rates. The experimental results showed that L- and D-lactic acid were absorbed from the pouches of the duodenum, jejunum, and ileum throughout the 60 minutes. In the test solutions with pH 5.3, 420mOsmol/kg, and 12.5mM lactic acid that are in vivo conditions of light lactic acidosis, the mean absorption rates of D-lactic acid and L-lactic acid pooled from three pouches were similar, 0.07micro mol/cm2/min and 0.06micro mol/cm2/min, respectively, based on absorptive surface area. The mean absorption rates of DL-lactic acid from the duodenum, jejunum, and ileum pouches were almost the same, 0.14, 0.14, and 0.11micro mol/cm2/min, respectively. The absorption of lactic acid varied depending on lactic acid concentration, and there was a curvilinear relationship between lactic acid concentration and its absorption rate. A decrease in pH and osmotic pressure resulted in significant, corresponding increases in the absorption of lactic acid (P<0.0001 and P<0.05, respectively).     

Density,activity, and diversity of bacteria indigenous to a karstic aquifer

The microbial ecology of karstic ground water is largely unknown. The density, activity, and diversity of bacteria indigenous to subsurface karstic material in Mammoth Cave National Park, Mammoth Cave, Kentucky were studied using minimally disruptive, on-site procedures. Two sites, located 100 m below the surface and consisting of saturated fine to coarse sand in pooled water, were examined. Samples were taken aseptically using modified, sterile 60-cc syringes. Total cell and total respiring cell densities were determined using an acridine orange/p-iodonitrotetrazolium violet (AO/INT) staining procedure. Cells in selected cores were stained with INT and incubated in the cave for 4 h prior to fixing with glutaraldehyde and subsequent transport to the laboratory. Cells were stained with AO in the laboratory. Low- and high-nutrient media were used to determine viable cell counts. Plates were incubated in the cave for 1 day at ambient temperature prior to transportation to the laboratory in an insulated cooler. Viable cell counts ranged from 1.0 × 106 to 8.1 × 106 cells wet g^–1 of sediment. Total direct counts were 3.9 × 106 and 1.4 × 107 cells wet g^–1 for the Olivia's Dome and the Catherine's Dome sites, respectively. Viable cell counts were highly similar to respiring cell counts at both sites. At the Olivia's Dome site, viable cell counts represented 26–31% of the direct cell counts, while 58% of the total cell count were actively respiring. At the Catherine's Dome site, viable cell counts represented 11–58% of the direct counts, while 53% of the cells were actively respiring. A total of 237 strains recovered from low- and high-nutrient media at both Olivia's and Catherine's Domes, and 10 reference strains were examined for 117 morphological, biochemical, and physiological characteristics. Results were coded in a binary fashion and analyzed using numerical taxonomic techniques. Similarity values were calculated using a simple matching coefficient. Fifty-two clusters, ranging in size from 2 to 13 members, were defined at the 80–85% similarity level with the weighted pair-group mathematical average algorithm (WPGMA). The matrix was examined using the Jaccard coefficient and WPGMA clustering to control for distortion due to negative matches and varying group size. Presumptively identified genera include, Arthrobacter, Brevibacterium, Bacillus, Cornyebacterium, Actinomyces, Aureobacterium, Chromobacterium, and Mycobacterium. Pseudomonas spp. were not recovered. Fifty percent of the clustered operational taxonomic units (OTUs) were not identified. Thirty percent of the clustered OTUs were irregular, asporogenous, Gram-positive rods. The bacterial communities varied between sites, and isolation medium had a strong influence on the strains recovered. The bacterial community in the karstic sediments sampled exhibits a high degree of diversity having no dominant strain or strains.Correspondence to: K.J. Rusterholtz     

Infection and nodulation of clover by nonmotile Rhizobium trifolii.

Nonmotile mutants of Rhizobium trifolii were isolated to determine whether bacterial motility is required for the infection and nodulation of clover. The nonmotile mutants were screened for their ability to infect and nodulate clover seedlings in Fahraeus glass slide assemblies, plastic growth pouches, and vermiculite-sand-filled clay pots. In each system, the nonmotile mutants were able to infect and nodulate clover.     

Nodule protein synthesis and nitrogenase activity of soybeans exposed to fixed nitrogen

Nitrate or ammonium was added to soybean (Glycine max L. Merrill cv Corsoy) plants grown in plastic pouches 10 days after nodules first appeared. By the third day of treatment with 10 millimolar nitrate, nitrogenase specific activity (per unit nodule weight) had decreased to 15% to 25% of that of untreated plants. Longer incubations and higher concentrations of nitrate had no greater effect. In addition, exogenous nitrate or ammonium resulted in slower nodule growth and decreased total protein synthesis in both the bacterial and the plant portion of the nodule (as measured by incorporation of ³⁵S). Two-dimensional gel electrophoresis revealed that the nitrogenase components were not repressed or degraded relative to other bacteroid proteins. In the presence of an optimal carbon source, the nitrogenase specific activity of nodules detached from nitrate-treated plants was equivalent to that of nodules from untreated plants. These results are consistent with models that propose decreased availability or utilization of photosynthate in root nodules when legumes are exposed to fixed nitrogen.     

Actigraph accelerometer-defined boundaries for sedentary behaviour and physical activity intensities in 7 year old children

Background

Accurate objective assessment of sedentary and physical activity behaviours during childhood is integral to the understanding of their relation to later health outcomes, as well as to documenting the frequency and distribution of physical activity within a population.

Purpose

To calibrate the Actigraph GT1M accelerometer, using energy expenditure (EE) as the criterion measure, to define thresholds for sedentary behaviour and physical activity categories suitable for use in a large scale epidemiological study in young children.

Methods

Accelerometer-based assessments of physical activity (counts per minute) were calibrated against EE measures (kcal.kg⁻¹.hr⁻¹) obtained over a range of exercise intensities using a COSMED K4b² portable metabolic unit in 53 seven-year-old children. Children performed seven activities: lying down viewing television, sitting upright playing a computer game, slow walking, brisk walking, jogging, hopscotch and basketball. Threshold count values were established to identify sedentary behaviour and light, moderate and vigorous physical activity using linear discriminant analysis (LDA) and evaluated using receiver operating characteristic (ROC) curve analysis.

Results

EE was significantly associated with counts for all non-sedentary activities with the exception of jogging. Threshold values for accelerometer counts (counts.minute⁻¹) were <100 for sedentary behaviour and ≤2240, ≤3840 and ≥3841 for light, moderate and vigorous physical activity respectively. The area under the ROC curves for discrimination of sedentary behaviour and vigorous activity were 0.98. Boundaries for light and moderate physical activity were less well defined (0.61 and 0.60 respectively). Sensitivity and specificity were higher for sedentary (99% and 97%) and vigorous (95% and 91%) than for light (60% and 83%) and moderate (61% and 76%) thresholds.

Conclusion

The accelerometer cut points established in this study can be used to classify sedentary behaviour and to distinguish between light, moderate and vigorous physical activity in children of this age.     

Autoregulation of soybean nodulation: Delayed inoculation increases nodule number

The influence of seedling age at the time of inoculation on the regulation of nodule number in soybean (Glycine max [L.] Merr.) was examined in cv. Williams 82 and its hypernodulating mutant NOD1-3. Nodulation was evaluated on plants grown in plastic growth pouches or in vermiculite in 50- or 500-ml glass containers in growth chamber studies. Seeds or seedlings were inoculated once with Bradyrhizobium japonicum strain USDA 110 (10^k cells seedling^?1) between 0 and 15 days after sowing at 3- or 5-day intervals and were grown for 21 days after inoculation. Nodule number plant^?1 was similar across inoculation times in plants grown in growth pouches, but was significantly greater when inoculation was delayed and plants were grown in vermiculite in 500-ml containers. Plant culture in vermiculite in 50- or 500-ml containers confirmed the suppressive effect of restricted space for root growth on nodulation. Inoculation with 10⁵ or 10⁹ USDA 110 cells revealed that nodulation was inhibited by a high inoculum dose. There was a large increase in nodule number plant^?1 when plants were transferred from a restricted rooting environment (growth pouch culture) to a nonrestricted rooting environment (2-1 hydroponic pots). Autoregulation was also examined in split-root assemblies of plants in 500-ml containers of vermiculite. Controls involved concurrent inoculation of both root halves at 0. 4 or 8 days after transplant. Treatments involved time-separated inoculations of root halves with the primary and secondary inoculations being separated by 4 days. Plants were harvested at 21 days after inoculation. Williams 82 exhibited autoregulation of nodule number on the root half receiving delayed inoculation, regardless of plant age at the time of primary inoculation. Total nodule number plant^?1 invariably increased with later inoculation times. In contrast. NOD1 - 3 exhibited little, if any, autoregulation of nodule number. It was concluded that although Williams 82 exhibits autoregulation of nodule number and NODI - 3 does not, there was no finite limit to nodule number in either line since any delay in inoculation resulted in formation of a greater nodule number on both lines if root growth was not restricted. Nodule number in Williams 82 and NODI - 3 appears to be a function of infection sites (root size) at the time of inoculation and of subsequent plant growth.     

DNA extraction during giemsa differentiation of chromatids singly and doubly substituted with BrdU

Human lymphocytes were cultured in ³H-labelled BrdU. Cells were pretreated to induce differentiation, autoradiographed and Giemsastained. DNA extraction was deduced if grain counts were lower in differentiated mitoses compared with untreated controls. — The differentiation method involved sequential pretreatments with short wave UV and 2 × SSC at 60 ° C. This removed 34% of label from first division cells (with TB.TB chromosomes) but relatively more (53%) from second division (TB.BB chromosomes). In second division cells, about two thirds of label was lost from pale (BB) chromatids but only one third from dark (TB) chromatids. The UV and SSC pretreatments acted in collaboration, since neither alone reduced grain counts significantly. — On testing other methods, similar preferential DNA extraction was obtained with Perry and Wolff's FPG method, and with the hot salt pretreatment of Korenberg and Freedlender. However, good Giemsa differentiation could also be obtained using Hoechst 33258 and light pretreatments without any DNA loss. Reverse differentiation patterns (TB pale, BB dark) induced by warm acids resulted in extraction of nearly two thirds of ³H-BrdU label, but relative loss was the same from pale and dark chromatin. Direct reverse staining using alkaline Giemsa did not result in any loss of label. — Thus preferential DNA loss from pale stained chromatin underlies differentiation methods using light plus hot salt pretreatments, but it is not obligatory for good differentiation using other techniques.     

Acetorphan, an enkephalinase inhibitor, decreases gastric secretion in cats

Acetorphan is an inhibitor of "enkephalinase" (EC 3.4.24.11) which has been shown to reduce in vivo and in vitro the degradation of enkephalins and other peptides. The effects of acetorphan on gastric secretion were studied in cats fitted with gastric fistulae and Heidenhain pouches. Acetorphan inhibited by 40-60% the acid secretion from the gastric fistulae after stimulation by submaximal doses of pentagastrin, histamine and 2 deoxy-D-glucose. These inhibitions were reduced or suppressed by naloxone. The meal-stimulated secretion from the fistulae was not changed after acetorphan. Acetorphan slightly and progressively reduced the pentagastrin-stimulated acid output from the Heidenhain pouches, and this effect was naloxone resistant. No change was found in the secretion from Heidenhain pouches under histamine stimulation, while meal-induced secretion of the pouches was increased by acetorphan, and this increase was not prevented by naloxone. Endogenous opioids probably exert an inhibitory regulatory control upon the gastric secretion of cats. In addition, non-opioid factors may be involved in the effect of acetorphan on meal-stimulated secretion.     

Preclinical Evaluation of Radiation-Induced Toxicity in Targeted Alpha Therapy Using [211At] NaAt in Mice: A Revisit

We recently reported the dose-dependent therapeutic effect of ²¹¹At-NaAt in differentiated thyroid cancer xenograft models. In the present study, we evaluated the radiation-induced toxicity of ²¹¹At-NaAt using detailed hematological, biochemical, and histological analyses. Biodistribution of ²¹¹At-NaAt was measured in normal ICR mice (n = 12), absorbed doses in the major organs were calculated. Groups of ICR mice (n = 60) were injected with 0.1 MBq or 1 MBq of ²¹¹At-NaAt, using saline as the control group (n = 30). Body weight and food intake were followed up for 60 days. Blood cell counts and serum level of biochemical parameters were measured 3, 7, 15, 29, 60 days after injection. Histological analyses of the major organs with hematoxylin and eosin staining were performed. Biodistribution study revealed a high-absorbed dose in the thyroid gland, stomach, bladder, heart, lungs, spleen, kidneys, and testis. The 0.1 MBq group showed no abnormalities. The 1 MBq group showed decreased body weight and food intake. Histological analysis showed atrophy and fibrosis in the thyroid gland, a transient hypospermatogenesis in the testis on day 29 was found in one mouse. Hematological toxicity was mild and transient. The total cholesterol, albumin, and total protein increased with no signs of recovery, which was considered to be caused by hypothyroidism. High-dose administration of ²¹¹At-NaAt showed transient toxicity in the white blood cells and testis without severe hematological or renal toxicity, suggesting its tolerable safety as targeted alpha-therapy for differentiated thyroid cancer in the 1 MBq group.     

Persistence and efficacy of spinosad residues in farm stored wheat

Degradation and insecticidal effectiveness of spinosad residues were evaluated in Kansas during November 2000 to November 2001 in farm bins holding wheat (34-metric ton capacity). About 50 kg of hard red winter wheat from each of three bins were brought to the laboratory and treated separately with 1-ml aqueous suspensions of spinosad to provide rates of 0.1, 0.5,1, 3, 6 mg (AI)/kg of wheat. Wheat treated with distilled water served as the control treatment. Untreated and spinosad-treated wheat samples (250 g each) were placed in three plastic pouches of two different mesh sizes, and buried 2.5 cm below the grain surface. Pouches with large mesh openings were used to monitor insect infestations and kernel damage in untreated and spinosad-treated samples. Pouches with small mesh were used for extracting spinosad residues and for conducting laboratory bioassays with adults of the lesser grain borer, Rhyzopertha dominica (F.) and red flour beetle, Tribolium castaneum (Herbst) at 28 degrees C and 65% RH. Wheat temperature and relative humidity near the pouches during the 1 yr of storage ranged from -10 to 32 degrees C and 50 to 70%, respectively. Moisture of wheat samples varied from 12.4 to 13%. Observed spinosad residues on wheat samples were 25% less than the calculated rates of 0.1 to 6 mg/kg. However, these residues were stable during the 1 yr of storage, and killed all R. dominica adults exposed for 14 d in the laboratory. Mortality of T. castaneum adults increased with an increase in spinosad rate. The linear regression slope of LD50s (0.3-2.7 mg/kg) against storage time was not significantly different from zero, indicating no loss in spinosad toxicity to T. castaneum adults. Insect species, insect numbers, and kernel damage over time in wheat samples inside pouches with large mesh openings were highly inconsistent, and failed to accurately characterize spinosad performance. Laboratory bioassays with R. dominica and T castaneum adults using grain from pouches with small mesh openings accurately gauged spinosad persistence and insecticidal activity under the field conditions.     

Types and Distribution of Anaerobic Bacteria in the Large Intestine of Pigs

An examination was made of various sites along the length of the swine large intestine, using strictly anaerobic culture methods. Sites were separated by differential washing into fractions described as lumenal content, lumenal surface layer, and intestinal wall tissue. Direct microscopic clump counts averaged 13.3 × 10¹⁰ organisms per g (dry weight) of material in the lumenal content, 14.0 × 10¹⁰ in the surface layer, and 5.1 × 10¹⁰ in the intestinal wall tissue. Both direct microscopic counts and viable culture counts were higher from the lumenal content and surface layer than from the intestinal tissue at all sites sampled in the intestine. Cultural counts averaged 56.2% of the direct microscopic counts in lumenal content and surface layer and 20.2% in intestinal tissue. Over 90% of the bacteria isolated were gram positive and consisted mainly of gram-positive cocci, lactobacilli, eubacteria, and clostridia. Of 192 isolates recovered, only 124 could be assigned to recognized species.