Biomedical subjects

D B Bates

Publications and source records attributed to D B Bates.

15 recordsLinked to original sources

PubMed2001

Source and level of energy supplementation for yearling cattle fed ammoniated hay.

Brahman x British crossbred steers were used in growth and digestion trials to evaluate the response of source (corn, sugar cane molasses, or soybean hulls) and feeding rate (0, 1.4, or 2.8 kg DM per steer daily in the growth trials; 0, 15, or 30% of the ration DM in the digestion trial) of energy supplementation in cattle fed ammoniated (4% of forage DM) stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) hay. Cattle on all treatments were fed 0.5 kg cottonseed meal daily. In the growth trials, steers grazed dormant bahiagrass (Paspalum notatum) pasture. Increasing the levels of supplementation decreased hay intake but increased total dietary intake for all diets (P < 0.07). Daily gain and feed efficiency of steers were improved (P < 0.03) with supplementation. Steers supplemented with corn or soybean hulls at 2.8 kg DM/d had a higher ADG (0.92 kg) and gain/feed (0.103) than steers supplemented with molasses (0.78 kg, 0.08, respectively) at the same level. Seven crossbred steers (200 kg) were used in a five-period digestion trial to evaluate apparent OM, NDF, ADF, and hemicellulose digestibility. Apparent OM digestibility of all diets increased linearly (P = 0.02) as the level of supplementation increased. Apparent NDF and ADF digestibility decreased (P < 0.03) as the level of supplementation with corn or molasses increased, whereas increasing the level of soybean hulls in the diet increased (P < 0.06) apparent NDF and ADF digestibility. Four ruminally fistulated crossbred steers (472 kg) were used in a 4 x 4 latin square design to investigate ruminal characteristics with energy supplementation at 30% of ration DM. Ruminal pH in steers supplemented with soybean hulls or corn declined after feeding. Ruminal pH decreased more rapidly with corn supplementation and remained below 6.2 for a longer period of time than with the other diets. Ruminal pH did not change within 24 h after feeding for steers fed the control or molasses diets. No change in total VFA concentration was observed in steers fed molasses or corn. Total ruminal VFA concentration in steers supplemented with soybean hulls increased initially after feeding and then declined within 24 h after feeding. Soybean hulls produced fewer negative associative effects than corn when fed with ammoniated stargrass hay at 2.8 kg DM/d. The reduced gain/feed of steers supplemented with molasses compared to soybean hulls or corn indicates that molasses was not utilized as efficiently as the other energy sources.

Ammonia↗

PubMed2000

RecA protein-dependent R-loop formation in vitro.

The RecA protein of Escherichia coli, which has crucial roles in homologous recombination, DNA damage repair, induction of the SOS response, and SOS mutagenesis, was found to catalyze assimilation of complementary RNA into a homologous region of a DNA duplex (R-loop). The reaction strictly requires a region of mismatch in the duplex, which may serve as a nucleation site for RecA protein polymerization. The optimum conditions for the assimilation reaction resemble those for the previously studied RecA protein-catalyzed homologous pairing and strand exchange reaction between two DNA molecules. Our finding lends strong support to the proposal that RecA protein-catalyzed assimilation of a transcript into duplex DNA results in formation of an R-loop at certain regions of the chromosome and that, when stabilized, the R-loop can serve as an origin of chromosome replication.

Adenosine Triphosphate↗

PubMed1999

Evaluating copper lysine and copper sulfate sources for heifers.

The effects of feeding different sources and quantities of Cu to heifers were evaluated in a 211-d experiment. Forty crossbred predominantly Brahman x Hereford heifers averaging 13.5 mo of age and 301 kg were initially depleted of Cu. The depletion diet was fed for 70 d and consisted of low Cu and high antagonist minerals, Fe, S, and Mo at 1000 mg/kg, 0.5%, and 5 mg/kg (dry basis), respectively. On d 71, heifers continued to receive the antagonistic minerals and were allotted equally to five Cu treatments: 1) control, no additional Cu source; 2) 8 mg of Cu/kg from CuSO4; 3) 16 mg of Cu/kg from CuSO4; 4) 8 mg of Cu/kg from Cu lysine; and 5) 16 mg of Cu/kg from Cu lysine. When no notable change in concentration of Cu in the liver was observed, d 169, a second diet was formulated. The heifers were fed the same Cu treatments, but S and Mo were removed and Fe was lowered to 50 mg/kg. This diet was then fed for the final 42 d of the experiment. In addition to performance, concentrations of Cu, Fe, and Zn in the plasma and liver, plasma ceruloplasmin, hemoglobin, superoxide dismutase (SOD) activity of neutrophils and lymphocytes, and a cell mediated immune response (phytohemagglutinin-P, PHA) were measured. Heifers in this study had increased growth over time, but there were no treatment differences for growth and average daily gain. Liver and plasma Cu concentrations were not greatly influenced by different supplemental Cu sources. However, compared with other treatments, Cu lysine (16 mg/kg) increased liver Cu in cattle that were deficient and tended to increase plasma Cu in animals that were marginally deficient in Cu. Iron concentrations decreased over time in liver and plasma, but there was no difference in Fe and Zn concentrations in liver and plasma among treatments. Differences in ceruloplasmin and hemoglobin concentrations were significant over time but not among treatments. The SOD activity in neutrophils did not change over time, but SOD activity of lymphocytes increased over time. For the PHA immune response test, there was no effect of time or a time by treatment interaction. These data suggest that all Cu sources were available, but Cu at 16 mg/kg from Cu lysine was more beneficial than were other sources and particularly for heifers with low Cu status.

Animal Nutritional Physiological Phenomena↗

PubMed1998

Are minichromosomes valid model systems for DNA replication control? Lessons learned from Escherichia coli.

Initiation of chromosome replication is a key event in the life cycle of any organism. Little is known, however, about the regulatory mechanisms of this vital process. Conventionally, the initiation mechanism of chromosome replication in microorganisms has been studied using plasmids in which an origin of chromosome replication has been cloned, rather than using the chromosome itself. The reason for this is that even bacterial chromosomes are so large that biochemical and genetic manipulations become difficult and cumbersome. Recently, the combination of flow cytometry and genetic methods, in which modifications of the replication origin are systematically introduced onto the chromosome, has made possible detailed studies of the molecular events involved in the control of replication initiation in Escherichia coli. The results indicate that requirements for initiation at the chromosomal origin, oriC, are drastically different from those for initiation at cloned oriC.

Chromosomes, Bacterial↗

PubMed1997

The absence of effect of gid or mioC transcription on the initiation of chromosomal replication in Escherichia coli.

Despite the widely accepted view that transcription of gid and mioC is required for efficient initiation of cloned oriC, we show that these transcriptions have very little effect on initiation of chromosome replication at wild-type chromosomal oriC. Furthermore, neither gid nor mioC transcription is required in cells deficient in the histone-like proteins Fis or IHF. However, oriC that is sufficiently impaired for initiation by deletion of DnaA box R4 requires transcription of at least one of these genes. We conclude that transcription of mioC and especially gid is needed to activate oriC only under suboptimal conditions. We suggest that either the rifampicin-sensitive step of initiation is some other transcription occurring from promoter(s) within oriC, or the original inference of transcriptional activation derived from the rifampicin experiments is incorrect.

Bacterial Proteins↗

PubMed1997

Effects of supplemental energy source and amount on forage intake and performance by steers and intake and diet digestibility by sheep.

Two levels of concentrate supplements containing different types of carbohydrates (corn-soybean meal, CSBM; wheat middlings, WM; and soybean hulls, SBH) were evaluated for effects on forage intake and performance in growing steers and total diet digestibility in sheep. In Exp. 1, 63 crossbred yearling cattle (298 and 377 kg initial BW for yr 1 and 2, respectively) were given ad libitum access to chopped bermudagrass (Cynodon dactylon [L.]) hay with no supplementation (CONTROL) or with 25 or 50% of projected total TDN intake from CSBM, WM, or SBH. In Exp. 2, digestibilities of organic matter (OMD) and neutral detergent fiber (NDFD) were determined with sheep fed levels of hay and concentrates similar to those used in the growth trials. Hay intake was 1.99% of BW for steers fed hay alone and averaged 1.93% of BW in steers fed supplements at the low level. At the high level of concentrate supplementation, hay intake was depressed (P < .001) to a similar extent (1.63% of BW) in steers supplemented with CSBM, WM, or SBH. AT the low concentrate level, shrunk ADG was similar (.63 kg/d) among supplements, but at the high concentrate level steers fed SBH had higher (P = .06) shrunk ADG (.95 kg/d) than steers fed CSBM (.76 kg/d). Body condition score (BCS) increased more (P = .06) for CSBM- and SBH- than for WM-supplemented steers. Total tract OMD was lower (P < .001) in sheep fed WM (54.8% for low and 56.9% for high supplementation levels) than in sheep fed CSBM (57.4 and 62.6%) or SBH (57.2 and 62.5%). Total tract NDFD was higher (P < .001) for the SBH (58.9% for low and 63.3% for high levels) diets than for CSBM (54.6 and 51.0%) or WM (54.6 and 51.8%) diets. Supplements containing highly digestible fiber (SBH) produced less negative associative effects than high-starch supplements (CSBM) when fed with bermudagrass hay at the high level (.8 to 1% of BW), but no differences were found at the low feeding level (.4 to .5% of BW).

Animal Feed↗

PubMed1996

Use of sodium dodecyl sulfate polyacrylamide gel electrophoresis to measure degradation of soluble soybean proteins by Prevotella ruminicola GA33 or mixed ruminal microbes in vitro.

Degradation of soluble soybean meal proteins by Prevotella ruminicola GA33 and mixed ruminal bacteria was studied using SDS-PAGE. This technique facilitated the quantification of peptides (molecular weight > or = kDa) released during the partial hydrolysis of soybean proteins. In P. ruminicola incubations, conglycinin alpha and alpha' subunits were degraded completely within 4 h, whereas the beta subunit of beta-conglycinin as well as the basic and acidic polypeptide components of glycinin were more resistant to degradation. Several peptides derived from digested soybean proteins appeared during the incubation. The N-terminal amino acid sequences of these peptides were similar to amino acid sequences in soybean proteins. The N-terminus of a 23-kDa peptide was identical to the N-terminus of the beta subunit of beta-conglycinin; the N-terminus of a 59-kDa peptide differed from amino acids 101 to 115 of the alpha subunit of beta-conglycinin by two of 15 amino acids; the N-terminus of a 64-kDa peptide differed from amino acids 67 to 76 of the alpha' subunit of beta-conglycinin by three of 10 amino acids. The transient accumulation of these peptides when soluble soybean proteins were incubated with mixed ruminal microorganisms suggests a role for P. ruminicola in the early stages of protein digestion in the rumen. Approximately 30% of the soluble soybean protein incubated with mixed ruminal microorganisms was not degraded after 9 h, and SDS-PAGE indicated that the basic subunit of glycinin and several peptides (molecular weights less than 23 kDa) make an appreciable contribution to metabolizable protein when soybean protein is fed to ruminants.

Amino Acid Sequence↗

PubMed1995

The DnaA box R4 in the minimal oriC is dispensable for initiation of Escherichia coli chromosome replication.

We have developed a genetic system with which to replace oriC+ on the Escherichia coli chromosome with modified oriC sequences constructed on plasmids. Using this system we have demonstrated that chromosomal oriC can tolerate the insertion of a 2 kb fragment at the HindIII site between DnaA boxes R3 and R4, whereas the same insertion completely inactivates cloned oriC. We have further found that although R4 is essential for the origin activity of cloned oriC, cells carrying a deletion of R4 in chromosomal oriC are viable. These results indicate that the oriC sequence necessary for initiation of chromosome replication is different from the so-called minimal oriC that was determined with cloned oriC. Flow cytometric analyses have revealed that these oriC mutations confer the initiation asynchrony phenotype. Introduction of the R4 deletion into a fis::kan mutant, which lacks the DNA bending protein FIS, renders the mutant cells inviable.

Alleles↗

PubMed1994

DNA replication triggered by double-stranded breaks in E. coli: dependence on homologous recombination functions.

Homologous recombination-dependent DNA replication (RDR) of a lambda cos site-carrying plasmid is demonstrated in E. coli cells when the cells express lambda terminase that introduces a double-stranded break into the cos site. RDR occurs in normal wild-type cells if the plasmid also contains the recombination hotspot chi. Chi is dispensable when cells are induced for the SOS response or contain a recD mutation. recBC sbcA mutant cells are also capable of RDR induction. A recN mutation greatly reduces RDR in normal cells, but not in SOS-induced cells. RDR proceeds by the theta mode or rolling circle mode of DNA synthesis, yielding covalently closed circular plasmid monomers or linear plasmid multimers, respectively. Previously described inducible stable DNA replication is considered to be a special type of RDR that starts exclusively from specific sites (oriMs) on the chromosome.

Bacterial Proteins↗

PubMed1991

Effects of a microbial inoculant and(or) sugarcane molasses on the fermentation, aerobic stability, and digestibility of bermudagrass ensiled at two moisture contents.

Tifton 81 bermudagrass was harvested and ensiled either directly (D; 32.4% DM) or wilted (W; 44.1% DM). Four treatments applied to each harvesting method were 1) control (C), or no additive; 2) dried cane molasses (M) at 5% of DM; 3) microbial inoculant (I; Pioneer 1174); and 4) a combination of Treatments 2 and 3 (MI). Wilting reduced the rate of decline of silage pH (P = .001) and produced silages with greater lactic acid concentrations (P = .069), lower acetic acid (P = .001) and ammonia contents (P = .001), and greater in vitro OM (IVOMD; P = .001) and ADF digestibilities (IVADFD; P = .001). These high-quality silages were less stable under aerobic conditions, as evidenced by greater average temperatures (P = .001) and greater yeast and mold counts (P = .001). Adding M to D forage resulted in silage with lower pH (P = .001), greater concentration of lactic acid (P = .001), greater IVOMD (P = .092), and lower acetic acid (P = .009) and ammonia concentrations (P = .002) than inoculated D silage. Wilted silage treated with MI averaged lower pH (P = .025), greater lactic acid content (P = .001) and IVOMD (P = .001), and lower acetic acid (P = .001) and ammonia concentrations than silages treated with M or I alone. These results indicate that wilting improved bermudagrass silage the most, and that the addition of molasses and inoculant to wilted bermudagrass further enhanced silage quality.

Aerobiosis↗

PubMed1989

Lasalocid-catalyzed proton conductance in Streptococcus bovis as affected by extracellular potassium.

The effect of extracellular potassium on lasalocid-catalyzed proton conductance in Streptococcus bovis 24 was measured by using the fluorescent probe 9-aminoacridine. Increasing external potassium concentration resulted in decreased proton flux into S. bovis cells exposed to the ionophore. These results suggest that lasalocid catalyzes K+/H+ exchange diffusion in S. bovis cells.

Aminoacridines↗

PubMed1989

Prevention of leucaena toxicosis of cattle in Florida by ruminal inoculation with 3-hydroxy-4-(1H)-pyridone-degrading bacteria.

Ruminal microorganisms in cattle at a Florida agriculture research station did not have the ability to detoxify leucaena by degradation of 3-hydroxy-4(1H)-pyridone (3,4,-DHP), but a DHP isomer (2,3-DHP) was degraded in some cattle. Cattle with microorganisms that degraded 2,3-DHP were mostly Senepol cattle imported from St. Croix, US Virgin Islands, where leucaena is an indigenous species. Hereford cattle at the research station in Florida generally did not degrade 3,4-DHP or 2,3-DHP. An experiment was conducted in which a pure culture of 3,4-DHP-degrading bacteria was inoculated into Hereford cattle (with ruminal fistula) grazing leucaena. The bacteria successfully colonized the rumen of recipient cattle and persisted through the following winter when there was no leucaena in the diet.

Animals↗

PubMed1987

Efficacy of amoxicillin trihydrate for the treatment of experimentally induced foot rot in cattle.

Twenty holstein heifers were intradermally inoculated in the interdigital skin with a suspension containing Fusobacterium necrophorum and Bacteroides melaninogenicus to induce acute foot rot. Lesions, lameness, and swelling were evaluated during the study, using a subjective scoring system. Rectal temperature, species and number of bacteria isolated, and change in body weight were monitored throughout the study. Ten heifers (treated) were given amoxicillin trihydrate (10 mg/kg of body weight, IM) for 5 days, beginning at the onset of lameness. The remaining 10 heifers (controls) were given physiologic saline solution IM. Treated heifers had less severe lesions and greater weight gain than did control heifers. Rectal temperatures of treated heifers did not differ significantly from those of control heifers. It was concluded that administration of amoxicillin trihydrate early in the course of acute foot rot may reduce the severity of lesions associated with foot rot in cattle.

Amoxicillin↗

PubMed1986

The effect of high dietary cation concentration on methanogenesis by steers fed diets with and without ionophores.

Nine steers (300 to 350 kg body weight) were divided into three groups and received either no ionophore, monensin or lasalocid in a 70% cracked corn basal diet for the entire experiment. Within each group, a 3 X 3 Latin-square design was used to evaluate the effect of a high cation concentration added to the diets on in vivo methanogenesis. The three cation treatments consisted of NaCl or KCl addition (Na or K increased to 2.5% of diet dry matter) or no cation addition. Sodium addition decreased methane production in the monensin group 19% when compared with control (P less than .05). Sodium also tended to decrease methane in the lasalocid group (P less than .1) but had no effect on the no-ionophore group. There was no significant effect of K addition on methane production when compared to no added cation. However, K tended to increase methane in both the lasalocid and no-ionophore groups and decrease methane in the monensin group. Results of this experiment support in vitro evidence that cation levels may modulate ionophore effects on methane production.

Animals↗

PubMed1984

Ionophores: their effect on production efficiency and mode of action.

Carboxylic polyether ionophores, when fed to growing ruminants improve efficiency of production. This review summarizes the observed effects of ionophores on the ruminal fermentation and the host animal. The effect of ionophores on prokaryotic and eukaryotic cells is described and this knowledge is then utilized to explain many of the observed ionophore effects on the rumen fermentations and host gastrointestinal physiology.

Animal Diseases↗