Comparisons of bacterial and archaeal communities in the rumen and a dual-flow continuous culture fermentation system using amplicon sequencing.

Dual-flow continuous culture (CC) fermenters are commonly used to study rumen fermentation in vitro. Research using culture-based and oligonucleotide techniques has shown that certain microbial populations within fermenters may be maintained at abundances similar to those observed in vivo. In this study, bacterial and archaeal communities in the rumen of dairy cattle and in a dual-flow CC fermentation system were compared using high-throughput amplicon sequencing targeting the V4 hypervariable region of 16S rRNA. We hypothesized that the in vitro system harbored a comparable bacterial and archaeal community to that observed in the rumen. Members of the Bacteroidetes and Firmicutes made up the 2 most abundant phyla in the rumen, inoculum, and fermenters and did not differ among sample types (P > 0.10). Similarly, Prevotellaceae, the most abundant family in all 3 sample types, did not differ based on source (P = 0.80). However, beta diversity analyses revealed that bacterial and archaeal communities differed between fermenters and rumen samples (P ≤ 0.001), but fermenter bacterial and archaeal communities stabilized by day 4 of each period. While the overall bacterial and archaeal community differs between natural rumens and those detected in in vitro fermenter systems, several prominent taxa were maintained at similar relative abundances suggesting that fermenters may provide a suitable environment in which to study shifts among the predominant members of the microbial community.

Vacuum packing: a model system for laboratory-scale silage fermentations.

AIMS: To determine the utility of vacuum-packed polythene bags as a convenient, flexible and cost-effective alternative to fixed volume glass vessels for lab-scale silage studies. METHODS AND RESULTS: Using perennial ryegrass or red clover forage, similar fermentations (as assessed by pH measurement) occurred in glass tube and vacuum-packed silos over a 35-day period. As vacuum-packing devices allow modification of initial packing density, the effect of four different settings (initial packing densities of 0.397, 0.435, 0.492 and 0.534 g cm(-3)) on the silage fermentation over 16 days was examined. Significant differences in pH decline and lactate accumulation were observed at different vacuum settings. Gas accumulation was apparent within all bags and changes in bag volume with time was observed to vary according to initial packing density. CONCLUSIONS: Vacuum-packed silos do provide a realistic model system for lab-scale silage fermentations. SIGNIFICANCE AND IMPACT OF THE STUDY: Use of vacuum-packed silos holds potential for lab-scale evaluations of silage fermentations, allowing higher throughput of samples, more consistent packing as well as the possibility of investigating the effects of different initial packing densities and use of different wrapping materials.

Bioprospecting Rumphius's Ambonese Herbal: Volume I.

Collaborating with traditional healers remains a valid method for the identification of potential lead compounds for novel pharmaceuticals. However, the knowledge of these traditional healers is rapidly being lost. Historic herbal texts provide a unique window to identify plants whose specific uses are no longer known. We have identified nine plants in the 17th century Ambonese Herbal: Volume I which were documented as having medicinal properties but which have not been examined in the current literature. We demonstrate that by evaluating plant and herb efficacy reports from historic texts, in the context of comprehensive modern databases such as NAPRALERT, we can ultimately identify candidate specimens deserving further pharmacological study.

A simple kinetic model of polymer adsorption and desorption.

A model of the desorption and adsorption of a polymer layer at a planar surface indicates a transition from exponential kinetics at high temperatures to nonexponential kinetics (stretched exponential with index one-half) at lower temperatures where these processes are diffusion-limited. Measurements of polystyrene desorption through polyisoprene overlayers show this predicted transition. Corroborative results are obtained for polystyrene desorption through polymethylmethacrylate overlayers. This identification of two distinct kinetic regimes suggests a unifying perspective from which to analyze polymer and biopolymer mobility at surfaces.

The ability of airborne Klebsiella pneumoniae to colonize mouse lungs.

A strain of Klebsiella pneumoniae was aerosolized and its survival in air at different relative humidities was studied. Survival was dependent upon relative humidity and aerosols were most stable during storage at a relative humidity of 60%. Mice were exposed to aerosols of K. pneumoniae produced at this humidity and lung samples taken at timed intervals after exposure. Fifteen strains of K. pneumoniae were tested for their ability to colonize mice, but only five were detectable in mouse lungs 7 days after exposure. Three of these strains persisted without an increase in bacterial numbers, regardless of the initial inoculum used. Two strains of K. pneumoniae, designated strains 15 and 16, persisted in a similar manner when used at a low dose; however, when the dose received per lung was increased there was a rapid multiplication of bacteria in the lungs.

Evaluation of the biological potency of new agmatine analogs of growth hormone-releasing hormone in the bovine.

Four new growth hormone-releasing hormone (GHRH) analogs with C-terminal agmatine were compared with the parent human GHRH(1-29)NH2 fragment to assess their abilities to increase serum concentrations of growth hormone (GH) in the bovine. The four analogs were: [D-Ala2, Nle27] GHRH(1-28)Agm (JG-73); [desNH2-Tyr1, Ala15, Nle27] GHRH(1-28)Agm (MZ-2-51); [desNH2-Tyr1, Ala15, D-Lys21, Nle27] GHRH(1-28)Agm (MZ-2-75); and [desNH2-Tyr1, D-Lys12,21, Ala15, Nle27] GHRH(1-28)Agm (MZ-2-87). The special characteristic of all four GHRH analogs is that arginine was replaced by agmatine (Agm) in Position 29. Five pregnant Holstein cows received these peptides subcutaneously at the following doses: 0.0156, 0.0625, 0.25, 1, and 4 micrograms/kg body wt. Each cow received each analog-dose combination according to a 5 x 5 Greco-Latin square design repeated for the 5-week treatment. Each cow also received saline vehicle only at the end of the 5-week treatment. Blood samples were collected from 30 min before until 360 min after treatment injection. Total area under the GH response curves for the 6-hr sampling period for each dose of each GHRH analog was compared. There was a linear dose-dependent GH release in response to hGHRH(1-29)NH2 and its four GHRH(1-28)Agm analogs. At the dose of 0.25 micrograms/kg, two GHRH analogs, JG-73 and MZ-2-75, stimulated greater GH release than hGHRH(1-29)NH2 (P less than 0.05). No differences were seen at the two lowest doses, 0.0625 and 0.156 micrograms/kg. When both total area under the GH response curves and GH peak amplitudes for each treatment were averaged for all doses, JG-73 and MZ-2-75 stimulated greater GH release than hGHRH(1-29)NH2 (P less than 0.05). In summary, three GHRH(1-28)Agm analogs, JG-73, MZ-2-75, and MZ-2-51, were found to be 11.8, 11.3, and 6.5 times more potent, respectively, on a weight basis, than hGHRH(1-29)NH2 in stimulating the release of GH in cows.

Fungal and actinomycete spore aerosols measured at different humidities with an aerodynamic particle sizer.

An aerodynamic particle sizer (APS) that uses laser Doppler velocimetry was used to determine aerodynamic diameters of spores of fungal and thermophilic actinomycete species common in mouldy hay, aerosolized at different humidities and temperatures. Results were compared with those obtained from inertial impaction in a cascade impactor. The APS gave slightly smaller measurements than the cascade impactor. Both methods gave aerodynamic diameters generally slightly smaller than the average spore dimensions observed on cascade impactor slides with a microscope. The latter measurements were less than axial dimensions given in the literature. Brief passage of spores through air at 95% relative humidity (RH) and 38 degrees C, compared with 40% RH and 20 degrees C, caused an immediate increase in their aerodynamic diameter and the breaking of chains of spores. Cultures maintained at 75% RH and aerosolized at 98% RH similarly produced larger spore particles than those passed through dry air. These findings have implications for mould-induced asthma and allergic alveolitis since they relate to physical behaviour of airborne spores and particle deposition sites in the lung.

New mechanism of nonequilibrium polymer adsorption.

Nonequilibrium states of surface composition can be extremely long-lived when polymer chains adsorb competitively. In a model system (polymethylmethacrylate adsorbed from CCl(4) onto oxidized silicon previously saturated with polystyrene), it is shown that a weakly adsorbing polymer was sterically pinned to a surface by a more strongly adsorbing polymer. The dynamical evolution of the surface composition was strongly nonexponential in time and non-Arrhenius in temperature; the phenomenology is analogous to bulk glasses. This interpretation offers a new mechanism to explain why weakly adsorbing chains may bind to surfaces, as well as a direction in which to look for a method to release them.

Physical protection against airborne pathogens and pollutants by a novel animal isolator in a level 3 containment laboratory.

A containment laboratory unit for research with aerosols of group 2 pathogenic microorganisms is described. The design criteria are based on current UK guidelines, which imply containment at group 3 level during aerosol production, storage, exposure of animals and sampling. Within the aerosol laboratory, primary containment is provided by a Henderson apparatus operating at a negative pressure to the external environment. Flexible film isolators under negative pressure are used for all hazardous microbiological work, e.g. tissue homogenization, and for housing infected laboratory rodents. A novel feature of the animal isolator is the separate ventilation of each cage, which minimizes the risk of cross-infection by aerosol transmission and ensures a similar environment within each cage. The results of an intentional release of a cloud of non-pathogenic microorganisms are presented to show the effectiveness of the containment barriers. Recommendations are given for the safe operation of a containment unit based upon practical experience.

Air hygiene in a pullet house: effects of air filtration on aerial pollutants measured in vivo and in vitro.

1. The natural history of air hygiene in a pullet house was assessed at three-weekly intervals using a combination of in vitro and in vivo assays. The performance of an internal air filter was also examined as an experimental technique for providing clean air. 2. Overall, air hygiene was poor by comparison with occupational standards for human health. The mass concentrations of respirable and inspirable dust were 1.4 and 11.3 mg/m3 compared to human exposure limits of 5 and 10 mg/m3 respectively. The concentration of ammonia was typically about 20 ppm. 3. The majority (greater than 99%) of airborne particles were non-viable. Commensal bacteria from the skin were the most numerous airborne bacteria. Scopulariopsis and Aspergillus spp. were the most prevalent fungi recovered from the air and bird's lungs respectively. The concentrations of airborne and lung fungi were positively correlated with ammonia concentrations. 4. The differences between in vivo and in vitro assays of airborne microorganisms suggest that an aerosol sampler should be devised which better mimics the physical and biochemical environment of the respiratory tract.

Active immunization of beef heifers against luteinizing hormone: III. Evaluation of dose and longevity.

Objectives were to evaluate the dose (Exp. 1) and purity of LH preparations (Exp. 2) on the anti-LH antibody response in heifers. Experiment 3 evaluated the longevity of LH immunization on sterility in heifers. In Exp. 1, 115 crossbred heifers were injected every 3 wk for 6 wk with .1, .33, 1.0, 3.0 or 9.0 mg of LH-ovalbumin. Concentrations of anti-LH antibodies generated were quantified by determining the percentage of binding of [125I]LH in serum. Mena LH binding over wk 0 to 12 was greater in heifers immunized with 1.0 mg conjugate than in heifers immunized with other doses (P less than .05). In Exp. 2, LH-ovalbumin conjugates were made from either LH-1, LH-2 or LH-3, which had relative immunological potencies of 2.1, 1.5 and 1.2 x NIH-LH-S1 units/mg, respectively. Forty-eight crossbred beef heifers were immunized against one of these three LH-ovalbumin conjugates, against LH conjugated without ovalbumin (LH-LH), or against ovalbumin alone (Oval). Estrous cycle activity was monitored by measuring serum progesterone concentration. Potency of the LH preparation used in the LH-ovalbumin conjugate was correlated (r = .94) with its ability to produce LH antibodies. In Exp.3, heifers were injected with 1 mg antigen every 2 wk for 10 wk. Five LH-1 heifers and five control heifers were slaughtered for examination of ovaries 10 wk after the last booster injection. The remaining five LH-I and five control animals were placed with a bull 8 wk after the last booster. All five control heifers conceived by 4 +/- 1 wk after placement with the bull whereas the LH-immunized heifers remained acyclic for 42 to 96 wk.

Air hygiene in a pullet house: spatial homogeneity of aerial pollutants.

1. The spatial distribution of aerial pollutants was measured in a large deep-litter pullet house, initially holding 10,000 birds, at 12 sites within the birds' breathing zone: on 6 occasions when the birds were between 8 and 27 d of age and on two occasions when the birds were 29 and 34 d of age and the flock size was halved. 2. The distribution of most pollutants appeared uniform, implying that all sites could be considered representative of the overall concentration of pollutant. 3. The concentration of ammonia differed between sites, probably because of local variations in the rate of release from the litter. The number concentration of non-respirable particles (greater than 5 microns in diameter) became heterogeneous when the flock size was halved. 4. The operation of two punka fans had no effect on the spatial distribution of aerial pollutants, but increased the maximum air speed from 0.08 to 0.16 m/s. 5. Recommendations are given for the minimum number of sampling sites necessary for a predetermined level of statistical accuracy. Eight sites at least are recommended for most aerial pollutants, though more are needed for the concentration of gaseous ammonia.

Vaccines against endogenous hormones: a possible future tool in animal production.

Vaccines have been widely used by the livestock industry to control and prevent disease. New technologies now permit development of vaccines against hormones that control reproduction, growth, and lactation in domestic farm animals. Results of research projects studying passive and active immunization against such hormones as estrogen, testosterone, LH, FSH, and somatotropin have demonstrated that reproductive efficiencies and growth can be altered through vaccination. Although immunizations against most of the hormones studied have proven effective in most cases, there remain problems related to longevity, consistency, and efficiency of response both within and between animals. When these areas have been clearly defined for individual hormones, standardized immunization regimens can be developed that will optimize antibody production in the animal, thus providing the animal agriculture industry with a powerful and profitable production tool.

Active immunization of heifers against luteinizing hormone-releasing hormone, human chorionic gonadotropin and bovine luteinizing hormone.

Seventy crossbred heifers were allotted randomly to 10 treatment groups. Treatments consisted of active immunization against ovalbumin (OV) conjugates of luteinizing hormone-releasing hormone (LHRH), human chorionic gonadotropin (hCG) and bovine luteinizing hormone (bLH) with each of three adjuvants. The adjuvants were complete Freund's adjuvant (CFA), M103(6) and 6VR6. Control animals were immunized against OV alone using CFA. Bulls were placed with the heifers following immunization to allow comparison of pregnancy rates between groups. Blood samples were collected weekly for 14 wk to determine antibody concentrations. Significant levels of circulating LH or LHRH antibodies were detected in heifers immunized with each of the hormone conjugates. Complete Freund's adjuvant was the most effective for stimulating antibody response to these antigens; however, M103 was equally effective when used with bLH or hCG conjugates. None of the heifers in the bLH-OV-CFA, bLH-OV-M103 or LHRH-OV-CFA immunization groups was pregnant at slaughter, whereas 71% of the OV-CFA control heifers were pregnant. Fertility suppression may be achieved in the bovine by active immunization against any of these three hormone conjugates. However, the duration of this study (8 wk after immunization) does not allow evaluation of the duration of effectiveness of each of the treatments.

A luteinizing hormone-releasing hormone-induced serum luteinizing hormone surge is not detectable in the milk of cows.

Six lactating Holstein cows were used to determine whether a serum luteinizing hormone (LH) surge induced by luteinizing hormone-releasing hormone (LHRH) could be detected in milk. A double antibody radioimmunoassay was evaluated for measuring LH in whole milk. Cows (d 10 of the estrous cycle) were injected with saline (time zero), followed by LHRH 12 h later. Blood samples were collected hourly for 12 h via jugular cannula following each injection; milk removal was accomplished every 2 h by a portable milking machine. On d 10 of the next estrous cycle, treatment, order was switched, with the same cows receiving LHRH at time zero and saline 12 h later. Approximately 2 h following LHRH treatment, serum LH levels peaked at 29 ng/ml and remained elevated for 5 h. There was no corresponding change in milk LH detected during the 12-h to 24-h period following the induced serum LH surge. Our conclusion is that the measurement of LH in the milk of cows shows little promise for predicting ovulation time in the cow.

Feeding Great Lakes fish to mink: effects on mink and accumulation and elimination of PCBS by mink.

The effects of feeding Great Lakes fish or fish products (carp, sucker, perch scraps, whitefish racks, and alewife fishmeal) to mink were studied. Growth and furring of mink were normal for all species of fish tested. However, mink fed carp failed to reproduce, and the reproductive performance and/or kit survival in groups fed the perch, whitefish, and sucker were inferior to the control. Only the alewife fishmeal diet supported reproduction and kit survival comparable to the control. PCB residues (as Aroclor 1254) accumulated in mink subcutaneous body fat to as much as 38 times the dietary level, while some individual congeners accumulated up to 200 times. The half-life of PCB in mink adipose tissue was determined to be 98 d. The toxicity of PCBs derived from Great Lakes fish was greater than that observed in previous studies with mink fed comparable levels of technical-grade PCBs.