Digestion characteristics by beef cattle consuming bermudagrass or bromegrass hay alone or with alfalfa and(or) corn

Cannulated beef cattle (four cows: 556 kg initial weight; four steers: 504 kg initial weight) were used in an experiment with two simultaneous Latin squares to determine effects of substituting alfalfa and(or) corn for vegetative bermudagrass (BER; 77% neutral detergent fibre and 5.5% acid detergent lignin) or mature bromegrass (BRO; 70% neutral detergent fibre and 6.6% acid detergent lignin) hay on digestion characteristics. For Controls, BER or BRO was fed at 1.32 or 1.54% body weight of cows and steers, respectively; other treatments entailed substitution for hay DM of alfalfa cubes (17%) or ground corn (33%). A protein supplement was given to all animals. In vitro neutral detergent fibre (NDF) digestion was slightly greater for BER than BRO. Supplement treatments did not affect the concentration of total volatile fatty acids or the molar proportion of propionate in ruminal fluid. True ruminal organic matter (OM) digestion was similar among diets; greater duodenal microbial OM flow and postruminal NDF digestion for BRO than BER diets were responsible for higher (P < 0.05) postruminal OM digestion for BRO diets. Supplement treatment did not affect duodenal microbial nitrogen flow or efficiency of microbial growth. Corn supplementation increased total tract OM digestion (P < 0.05). Alfalfa addition depressed total tract OM and NDF digestibilities more when added to BER than BRO; depressions in total tract NDF digestion with alfalfa and corn substitutions were additive. With constant DM intake, slightly less than ad libitum, alfalfa or corn substituted alone or together for hay did not improve characteristics of digestion by cattle consuming vegetative bermudagrass or mature bromegrass other than increased postruminal and total tract OM digestibilities with corn.

Cloning the partial cDNAs of mu-calpain and m-calpain from porcine skeletal muscle

Calpains are non-lysosomal proteases involved in myofibrillar protein degradation. To facilitate studying the expression of the porcine calpain genes and their influence on protein accretion, we have cloned partial cDNAs for mu- and m-calpain from porcine skeletal muscle via PCR amplification. A 289 bp fragment for mu-calpain and a 629 bp fragment for m-calpain were cloned into the EcoRV site of pBluescript II KS+ vector. The nucleotide sequence for porcine mu-calpain and m-calpain were 92% and 90% identical to corresponding regions of rabbit mu- and m-calpain, respectively. The deduced amino acid sequences for both mu- and m-calpain share 94% identity with respective rabbit mu- and m-calpains. Isoform specificity was validated by Southern hybridization of mu- and m-calpain probes with cloned mu- and m-calpain fragments and Northern hybridization with pig muscle mRNA. These clones will be used to evaluate the role of calpain expression in muscle hypertrophy.

Effects of various supplements on voluntary intake and performance by growing cattle consuming forage moderate to high in crude protein

Growing cattle were supplemented with substances to lessen or increase ruminal ammonia level to determine if consumption of moderate- to high-crude protein (CP) forage is limited by high ruminal ammonia absorption. In Experiment 1 (5 x 5 Latin square), five Holstein steers (198 kg) had ad libitum access to alfalfa cubes (17% CP) without supplementation or with corn at 0.25 or 0.75% body weight (BW) alone (LC or HC) or with 0.06% BW of zeolite (chabazite; LC-Z and HC-Z). Total daily organic water (OM) intake was not affected by treatment (6.08, 6.14, 6.11, 6.19 and 6.09 kg for control, LC, LC-Z, HC and HC-Z, respectively; SE 0.25). In Experiment 2, Simmental crossbred beef calves grazed fescue-clover paddocks in the spring (clipped forage: 21 to 27% CP) for 84 days and were supplemented with 0.25 or 0.75% BW corn alone or with added zeolite (0.06% BW) or lasalocid (0.5 mg/kg BW). Daily gain did not differ among treatments (1.24 to 1.31 kg/day). In Experiment 3 (6 x 6 Latin square), six Holstein steer calves (168 kg) had ad libitum access to medium-quality, orchardgrass-clover hay (15% CP). Steers received one of the following six treatments: no supplement (Control), 0.35% BW ground corn (C), corn plus 0.049% BW urea (C-U), 0.35% BW soybean meal (S), 0.205% BW feather meal (F) or 0.103% BW feather meal, 0.052% BW blood meal and 0.067% BW corn gluten meal (F-BG). Total daily OM intake was 5.00, 5.14, 5.00, 5.11, 4.84 and 4.70 kg for control, C, C-U, S, F and F-BG, respectively (SE 0.13). In Experiment 4 (6 x 6 Latin square), six Holstein steer calves (226 kg) were fed 0.75% BW of alfalfa cubes (19% CP) plus ad libitum access to medium- to high-quality orchardgrass hay (16% CP). Steers received one of the following six treatments: no supplement (Control), corn at 0.25% BW alone (c) or mixed with 0.12% BW peanut skins (C-PSK), a mix of high-CP feedstuffs high in ruminal escape protein (0.029% BW blood meal, 0.038% BW corn gluten meal and 0.028% BW feather meal; C-REP), 0.139% soybean meal (C-S) or soybean meal plus peanut skins (C-PSK-S). Total daily OM intake was 6.16, 6.25, 6.13, 6.52, 6.50 and 6.60 kg for control, C, C-PSK, C-REP, C-S and C-PSK-S, respectively (SE 0.10).(ABSTRACT TRUNCATED AT 400 WORDS)

Selective expression of mitogen-inducible cyclooxygenase in macrophages stimulated with lipopolysaccharide

Two forms of cyclooxygenase are known to be present in eukaryotic organisms: a cyclooxygenase (COX-1) first purified from ram seminal vesicles encoded by a 2.8-kilobase mRNA, and a newly discovered mitogen-inducible cyclooxygenase (COX-2) encoded by a 4-kilobase mRNA. Expression of these two forms of the enzyme in rat alveolar macrophages stimulated with lipopolysaccharide was investigated by 1) determining the activity of newly synthesized enzyme after inactivating the endogenous enzyme with aspirin; 2) comparing levels of newly synthesized enzyme proteins in cells treated with or without lipopolysaccharide; and 3) assessing the expression of the mRNAs encoding COX-1 and COX-2. Levels of enzyme proteins were assessed by Western blot analysis and immunoprecipitation of 35S-labeled enzyme using two different antibodies, one specific for COX-2 and the other recognizing both forms of the enzyme but preferentially recognizing COX-1. We report here that the enhanced cyclooxygenase activity induced by the bacterial lipopolysaccharide in rat alveolar macrophages is caused by selective expression of the COX-2. Expression of COX-2 in macrophages stimulated by lipopolysaccharide was completely inhibited by dexamethasone, whereas COX-1 was unaffected. In resting unstimulated macrophages, only COX-1 but not COX-2 was detected. Levels of mRNA for the COX-2 in macrophages were increased, but those of the COX-1 were not affected by lipopolysaccharide as assessed by reverse transcription coupled with polymerase chain reaction. These results indicate that increased synthesis of prostaglandins and thromboxanes in lipopolysaccharide-stimulated macrophages results from selective expression of COX-2.

Mapping of a human brain voltage-gated calcium channel to human chromosome 12p13-pter

Degenerate DNA oligomers coding for highly conserved regions of the voltage-gated calcium channel were synthesized for the polymerase chain reaction (PCR) using DNA from a human brain cDNA library as template. PCR amplified a 640-bp DNA fragment from the human brain cDNA library. Sequencing revealed that this fragment encodes part of a protein highly homologous to a subtype of the dihydropyridine-sensitive calcium channel cloned from rabbit heart and rat brain. Southern analysis of panels of somatic cell hybrids mapped the 640-bp fragment, CACNL1A1, to human chromosome 12p13-pter.

CD4 lymphocyte decline and survival in human immunodeficiency virus infection. The Military Medical Consortium for Applied Retroviral Research

The loss of the CD4 lymphocyte is the central pathophysiologic event in the progression of human immunodeficiency virus (HIV) infection. This retrospective study, based on review of data from deceased HIV patients followed in a single HIV clinic, was conducted to determine if the rate of CD4 lymphocyte decline was predictive of survival. Forty of 172 patients met defined criteria for inclusion in this study. For each patient, CD4-cell counts showed approximate exponential decline over time. A Cox regression analysis was used to assess the association of CD4 cell decline (half-life), race, age, gender, initial CD4-cell count, and treatment (anti-Pneumocystis carinii pneumonia prophylaxis and/or zidovudine vs. no therapy) on total survival (from initial CD4 cell count) and on remaining survival time after reaching a CD4 cell count of 100 (estimated). For all patients, the rate of CD4 cell decline was predictive of total survival (p = .009) but not for survival after reaching a count of 100 (p = .6). For patients who had never received therapy (6 patients), however, the CD4 half-life remained associated with survival time from 100 CD4 cells (p < .05) as opposed to the treated patients. Therapy was the single variable most predictive of both survival endpoints, resulting in an increase in median total survival of 27.2 mo (p < .00001) and of 15.4 mo from a CD4 cell count of 100 (p < .00004). Nonwhites had a slight survival disadvantage compared to whites (p = .08 overall; p = .02 from CD4 cell count of 100).(ABSTRACT TRUNCATED AT 250 WORDS)

Digestion, feed intake, and live weight gain by cattle consuming bermudagrass hay supplemented with whey

Three experiments were conducted with cattle consuming bermudagrass hay to determine whether low-level supplements of whey alone, corn alone, or whey plus corn affect feed intake, digestion, and(or) BW gain. Six ruminally and duodenally cannulated beef cows (574 kg), used in a Latin-square trial (Exp. 1), were fed bermudagrass hay without supplementation (control) or with 2.8% whey (low whey, LW), 5.6% whey (high whey, HW), 17.4% ground corn (C), 2.8% whey plus 14.9% corn (C-LW), or 5.6% whey plus 12.4% corn (C-HW). Supplementing with whey and(or) corn increased ruminal butyrate (8.8, 9.4, 10.0, 9.6, 10.5, and 11.0 mol/100 mol of total VFA for control, LW, HW, C, C-LW, and C-HW, respectively; SE = .20). Supplements did not affect microbial N flow at the duodenum. Six Holstein steer calves (158 kg) in a Latin square (Exp. 2) consumed bermudagrass hay ad libitum alone (control) or with .075 or .15% BW whey (LW and HW, respectively), .5% BW ground corn (C), or corn-whey mixes made by substituting whey for corn (C-LW and C-HW). Substituting .15% BW of whey for corn increased (P less than .05) total OM intake slightly (3.99, 3.84, 3.75, 4.11, 4.28, and 4.47 kg for control, LW, HW, C, C-LW, and C-HW, respectively; SE = .10). In an 84-d randomized block experiment (Exp. 3), 96 beef calves (194 kg) consumed (ad libitum) low-quality bermudagrass hay alone or with C, LW, HW, C-LW, or C-HW supplements.(ABSTRACT TRUNCATED AT 250 WORDS)

Estrogen negatively regulates rat gonadotropin releasing hormone (rGnRH) promoter activity in transfected placental cells

To dissect the functional architecture of the rat gonadotropin releasing hormone (GnRH) gene promoter and its regulation by estrogen, gene transfer studies were performed in a placental cell line. 5'-Deletional constructs demonstrated that cis-acting elements important for rGnRH promoter activity in placenta were contained within a region of the proximal promoter between -73 and -16 bp upstream of the transcription initiation site. In addition, an inhibitory region was found from -903 to -424. Deletion of sequences to -424 which removed the inhibitory region, produced a promoter fragment which exhibited a 50% inhibition of GnRH promoter activity in the presence of estrogen (E) and cotransfected estrogen receptor. Negative regulation by E was retained in constructs deleted to -73 bp. We conclude that sequences important for placental cell expression and estrogen regulation of rGnRH lie within the region from -73 to -16. In addition, potential repressor sequences active in placental cells are present between -903 to 424.

DL, Forster Jr. LA, Li F, West CP, Johnson ZB, Patil A, Sun W. Liveweight gain by beef calves grazing cool-season annual grass in the spring and supplemented with grass hays

Supplementing beef calves grazing cool-season annual grass with warm- or cool-season grass hay (0.4% liveweight), differing in cell wall content, depressed weight gain more by heifers than steers. Adding supplemental corn (0.8% liveweight) to hay only improved gain by heifers, though gain was not greater than controls for either gender. Key words: Cattle, beef, supplements, pasture, corn, hay

Cloning of the cDNA encoding a neuronal myosin heavy chain from mammalian brain and its differential expression within the central nervous system

The complete amino acid sequence of a neuronal myosin heavy chain (MHC) from mammalian brain (1999 amino acids, 230 kDa) has been deduced by sequencing cDNA clones isolated from a rat brain cDNA library. The library was screened using an affinity-purified polyclonal antibody that had been raised against myosin purified from a neuronally-derived cell line (Neuro-2A). Restriction digests of genomic DNA from Neuro-2A cells and rat brain are consistent with an identity of the sequenced isoform from these two sources. RNA blot analysis demonstrates this myosin to exhibit differential expression within the cerebral cortex and spinal cord. No expression was observed in liver, kidney, heart, spleen or skeletal muscle, or even within other regions of the brain. The sequence of this neuronal MHC is compared with those of other non-muscle MHCs, to which it shows an overall similarity of structure, especially with respect to conserved regions within the head (ATP binding site, actin binding site, reactive thiols) and the presence of an alpha-helical coiled-coil tail that can be arranged as 28-residue repeating units plus four skip residues. A unique non-helical tailpiece composed of 72 amino acid residues marks the C-terminus of this neuronal myosin isoform.

Molecular cloning, chromosomal mapping, and functional expression of human brain glutamate receptors

A full-length cDNA clone encoding a glutamate receptor was isolated from a human brain cDNA library, and the gene product was characterized after expression in Xenopus oocytes. Degenerate PCR primers to conserved regions of published rat brain glutamate receptor sequences amplified a 1-kilobase fragment from a human brain cDNA library. This fragment was used as a probe for subsequent hybridization screening. Two clones were isolated that, based on sequence information, code for different receptors: a 3-kilobase clone, HBGR1, contains a full-length glutamate receptor cDNA highly homologous to the rat brain clone GluR1, and a second clone, HBGR2, contains approximately two-thirds of the coding region of a receptor homologous to rat brain clone GluR2. Southern and PCR analysis of a somatic cell-hybrid panel mapped HBGR1 to human chromosome 5q31.3-33.3 and mapped HBGR2 to chromosome 4q25-34.3. Xenopus oocytes injected with in vitro-synthesized HBGR1 cRNA expressed currents activated by glutamate receptor agonists with the following specificity sequence: domoate greater than kainate much greater than quisqualate greater than or equal to alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid greater than or equal to L-glutamate much greater than N-methyl-D-aspartate. The kainate-elicited currents were specifically blocked by 6-cyano-7-nitroquinoxaline-2,3-dione but were insensitive to 2-amino-5-phosphonovalerate and kynurenic acid. These results indicate that clone HBGR1 codes for a glutamate receptor of the kainate subtype cognate to members of the glutamate receptor family from rodent brain.

Partition coefficient of luciferase from photobacteria in PEG/salt two aqueous phase system

The relationship between the logarithmic partition coefficient (K) of luciferase of photobacteria and PEG MW in the PEG/salt two aqueous phase system was shown to be a linear function. The hydrophilic PEG of lower MW facilitated the partition of luciferase into the top PEG-riching phase and gave a higher K value, while PEG of higher MW, its hydrophobic characteristic, made more enzyme partition into the bottom salt-riching phase and lower K value was obtained. In the PEG/trivalent salt system, such as phosphate and citrate, there was a turning-point on the linear relation between the log K and the PEG MW, but which never appeared if a divalent salt such as sulfate, succinate or tartrate was used in the system. When the system was composed of homogeneous PEG and ammonium sulfate, the K value was increased with the increment of the salt concentration, but after the salt concentration had reached at certain level, the K value was uninfluenced. When two kinds of PEG with different MW were used in this system a minimal K value appeared at certain concentration of ammonium sulfate, and the K value was raised when the salt concentration was either increased or decreased. Neither the proportion of the two kinds of PEG nor their total concentration used in the system showed any effect on the above patterns, although the K value may give some corresponding changes. (ABSTRACT TRUNCATED AT 250 WORDS)

Digestion and performance responses to lasalocid and concentrate supplements by beef cattle fed bermudagrass hay

Beef cattle consuming bermudagrass hay were not supplemented or received a limited amount of ground corn alone or with a mix of protein meals to determine influences of concentrate supplementation on digestion and performance when the ionophore lasalocid (200 mg daily) was given. With limited feed intake, supplement treatment did not change the acetate to propionate shift in beef cows occurring with lasalocid (P < 0.06). Lasalocid did not affect sites of digestion of organic matter or nitrogen with any supplement treatment. However, lasalocid decreased (P < 0.10) ruminal digestion of neutral and acid detergent fibre. Live-weight gain by growing beef calves ingesting bermudagrass hay ad libitum was higher (P < 0.05) with than without supplementation and tended (P < 0.12) to be greater for corn plus protein meals than for corn alone. Lasalocid did not affect or interact with supplement treatment in feed intake or live-weight gain of heifers (236 kg; no growth stimulant) or steers (237 kg; treated with 200 mg progesterone and 20 mg estradiol benzoate). Lasalocid at 200 mg daily did not improve digestion characteristics or influence performance by beef cattle consuming a Basal diet of bermudagrass hay. Further, effects of lasalocid were not modulated by supplementation with concentrate, concentrate type or sex or growth stimulant usage.

Endothelial cell adhesion on polyurethanes containing covalently attached RGD-peptides

Peptides based on cell-adhesive regions of fibronectin, Arg-Gly-Asp-Ser (RGDS), and vitronectin, Arg-Gly-Asp-Val (RGDV), were covalently bound to a polyurethane backbone via amide bonds. Nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies were used to monitor the reactions. The amount of grafted peptide was determined by amino acid analysis. X-ray photoelectron spectroscopy (XPS) suggested the presence of the grafted peptide at the polymer-air interface in vacuo. Dynamic contact angle analysis showed that, in water, the peptide-grafted polyurethane surfaces were more polar than the underivatized polyurethane indicating enrichment of peptide groups at the surface. The attachment and spreading of human umbilical vein endothelial cells (HUVECs) on the underivatized and peptide-grafted polyurethanes was investigated. The GRGDSY- and GRGDVY-grafted substrates supported cell adhesion and spreading even without serum in the culture medium. The GRGDVY-grafted substrate supported a larger number of adherent cells and a higher extent of cell spreading than the GRGDSY-grafted substrate. These RGD-containing peptide-grafted polyurethane copolymers may be useful in providing an easily prepared cell-adhesive substrate for various biomaterial applications.

[Effects of nicardipine on automaticity of sinoatrial node in rabbit heart]

The dual effects of nicardipine (Nic) on the automatic activity of sinoatrial (SA) node cell in rabbit heart had been observed using intracellular microelectrodes. Superfused with Nic 0.1, 0.5, 1.0, and 5.0 mumol.L-1 for 10 min, the spontaneous rate was decreased by 32%, 42%, 47%, and 69%, respectively. However, by superfusing with Nic 0.05 mumol.L-1, the spontaneous rate and the amplitude of action potentials were increased by 12% and 13% respectively. Nic 5.0 mumol.L-1 inhibited the positive chronotropic effects of isoproterenol and nicotine. The results suggest that Nic may block the calcium influx in SA node cells.

[Penicillin-resistant pneumococcal meningitis: report of two cases]

Cases of penicillin-resistant pneumococcal meningitis have been reported in other countries since 1977, but never before reported in Taiwan. In 1990, two cases of the disease were diagnosed here. Case one was a two-year-old boy who had had fever and vomiting for several days prior to admission. Under the impression of meningitis, a spinal tap was done. The CSF yielded pneumococcus, which was misinterpreted as sensitive to penicillin. Penicillin (400,000 units/kg/day) was given parenterally without effect. On the 12th day after admission, another spinal tap still yielded pneumococcus. This time the sensitivity test was reread with great care, and then reported to be penicillin-resistant pneumococcus. Minimal inhibitory concentration (MIC) of penicillin was performed simultaneously and it revealed 0.1 microgram/ml. Vancomycin (60 mg/kg/day) was substituted for penicillin. The patient became afebrile two days later, and was discharged ten days later without sequelae. Case two, a five-month-old girl, was diagnosed to have meningitis because of fever, vomiting, tense fontanel and seizure on admission. After a spinal tap was done, she was put on ampicillin and cefotaxime. The fever subsided two days later. At that time, the CSF was reported to grow pneumococcus, again misread as sensitive to penicillin. The antibiotics was switched to penicillin, but fever recurred. The second spinal tap still yielded pneumococcus which was sensitive to penicillin but resitstant to oxacillin. Based on experience with the first case, penicillin was changed to vancomycin, and performed MIC immediately. The MIC was 1.0 microgram/ml. The patient became afebrile two days later, and was discharged in good condition after ten days of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Digestion in steers and lactational performance of Jersey cows fed diets varying in natural protein level continuously or on alternate days

Five crossbred beef steers (515 kg) were used in a Latin square experiment and 36 lactating Jersey cows (12 primiparous, 310 kg; 24 multiparous, 365 kg) were used in a completely randomized design study to determine effects on characteristics of digestion and lactational performance of daily alternation of the dietary level of natural protein (NP). In Experiment 1, steers were fed diets of 50% bermudagrass hay and 50% concentrate. Concentrate was approximately 18% crude protein (CP), formulated to be 60, 80 or 100% NP (varying proportions of soybean meal, urea and ground corn), and was fed at 1.5% body weight (dry matter basis). These concentrates were fed daily or ones with 60 and 100% NP were fed on alternate days. Alternate day feeding did not markedly affect characteristics of digestion, including ruminal escape of feed protein, and NP level of concentrate fed continuously had no effects either. In Experiment 2, cows were subjected to treatments similar to those in Experiment 1, and performance on d 20-40 of lactation was measured. Concentrate was given at 1 kg (as fed)/2.15 kg milk produced, yielding a dietary concentrate level of approximately 40% (dry matter basis). Alternate feeding depressed (P less than 0.05) overall milk fat percentage. Alternate feeding increased production of milk and protein and body weight of primiparous cows but caused little change with multiparous cows. Besides increasing the dietary level of concentrate, perhaps alternate feeding regimes have utility to lower milk fat level without impairing milk production. Level of NP in concentrate fed continuously did not affect performance by multiparous cows though primiparous cow performance was generally enhanced, possibly because CP intake was adequate for multiparous cows but marginal for primiparous cows. However, overall, efficiency of production of solids-corrected milk rose slightly with increasing NP.

[Effect of atrial natriuretic factor on the automaticity of sinus node in guinea pig heart]

The effect of atrial natriuretic factor (ANF) on sinoatrial (SA) node cells in guinea pig heart was studied by using intracellular microelectrodes. When the heart superfused with ANF 0.025 and 0.05 mumol/L for 7 min respectively, the spontaneous rate showed no significant changes, but 0.1 mumol/L ANF resulted in a definite decrease by 7% (P less than 0.01). However, when ANF (0.025, 0.05 and 0.1 mumol/L) was superfused along with 0.5 mumol/L isoproterenol, the spontaneous rate was respectively depressed by 4, 12 and 22%. These results indicate that ANF can depress the positive chronotropic effect of isoproterenol. The mechanism of this action may be related to the blocking effect of ANF on T-type calcium channel of SA node.

Relationships of body weight, forage composition, and corn supplementation to feed intake and digestion by Holstein steer calves consuming bermudagrass hay ad libitum

Holstein steer calves (101 to 350 kg BW) consumed bermudagrass hay ad libitum without or with supplemental ground corn up to 1.0% of BW. As BW increased, total DMI increased quadratically (-2.459 + .05448 [BW]-.000073 [BW2] + .540 [corn DMI]; R2 = .83, sy.x = .655). Each kilogram of corn DM decreased bermudagrass DMI by .46 kg. Total digestible OM intake (kg) increased with BW and corn supplementation (.314 + .0127 [BW] + .441 [corn OM intake]; R2 = .79, sy.x = .444). Feed intake level accounted for approximately 2.5 times more variability in total digestible OM intake than digestion did. Corn supplementation decreased digestion of bermudagrass NDF (62.50 - 8.468 [corn DMI, % BW]; R2 = .13, sy.x = 8.121), with a similar decrease across BW. Increasing bermudagrass DMI (% of BW) decreased bermudagrass NDF digestion slightly, but variation accounted for was only 33% of that attributable to corn DMI (% of BW). Concentrations of common fiber fractions (NDF, ADF, cellulose, hemicellulose, and ADL) in bermudagrass explained very little variation in feed intake and digestion, indicating considerable influence of other factors. Bermudagrass intake and digestion were not related, and no substantial interactions were observed among steer BW, corn level, and bermudagrass composition.

[Identification of Chinese drugs by fluorescence spectrum]

Cortex Fraxini, Radix et Rhizoma Rhei, Semen Astragali Complanati, Semen Lini, Bulbus Fritillariae Cirrhosae, Bulbus Fritillariae Thunbergii and their confused medicinal materials have been identified by the fluorescence spectrum. This is a referential method for the identification of Chinese drugs.

Feed intake and digestion by Holstein steers fed warm or cool season grass hays with corn, dried molasses, or wheat middlings

This study determined the effects of adding a small amount of dried molasses to supplemental corn and of supplementing with corn, wheat middlings, or corn-wheat middlings mixture on intake and digestion by Holstein steers fed warn or cool season grass hays. Eight steers (175 kg BW), in two simultaneous Latin squares, were fed, once daily, bermuda-grass (72% NDF) or ryegrass-wheat (58% NDF) hay ad libitum, alone or with approximately .05% BW of dried molasses (with 31% roughage), 5% BW of ground corn, or both. Adding dried molasses to corn decreased feed intake but did not affect digestible OM intake. Total tract digestion of fiber from bermudagrass tended to be enhanced by adding dried molasses to corn. Eight steers (193 kg BW) were used in an experiment with the same design in which similar forages were fed alone or with corn (.5% BW), wheat middlings (.63% BW), or .25% BW of corn plus .31% BW of middlings. Feed intake for both grasses was similar among supplements. Wheat middlings depressed total tract fiber digestion more than corn with both forages. Supplementation with corn depressed fiber digestion slightly more with ryegrass-wheat than with bermudagrass, but wheat middlings had a slightly greater depressing effect on fiber digestion with bermudagrass. Associative effects of mixing corn and wheat middlings in OM digestion and digestible OM intake were negative for bermudagrass and positive for ryegrass-wheat. Interaction among characteristics of basal forage and concentrate modulated feed intake and digestion by ruminants.

[Quantitative determination of strychnine and brucine in semen Strychni and its preparations by gas chromatography]

Contents of strychnine and brucine in dry seeds of Strychnos nux-vomica and its preparations were determined by gas chromatography. The determination conditions were:support Gas Chrom Q; liquid phase 3% OV-101; stainless steel column 0.5 m x 3 mm; column temperature 265 degrees C; FID detector.

Dominant negative umuD mutations decreasing RecA-mediated cleavage suggest roles for intact UmuD in modulation of SOS mutagenesis

The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli. The UmuD protein shares homology with a family of proteins that includes LexA and several bacteriophage repressors. UmuD is posttranslationally activated for its role in mutagenesis by a RecA-mediated proteolytic cleavage that yields UmuD'. A set of missense mutants of umuD was isolated and shown to encode mutant UmuD proteins that are deficient in RecA-mediated cleavage in vivo. Most of these mutations are dominant to umuD+ with respect to UV mutagenesis yet do not interfere with SOS induction. Although both UmuD and UmuD' form homodimers, we provide evidence that they preferentially form heterodimers. The relationship of UmuD to LexA, lambda repressor, and other members of the family of proteins is discussed and possible roles of intact UmuD in modulating SOS mutagenesis are discussed.

[Study of mechanisms in the pathogenesis of myelodysplastic syndrome: changes in lymphocyte subpopulations]

The mechanism of pathogenesis in myelodysplastic syndrome (MDS) is still unknown up to the present day, but examination of blood and bone marrow from 22 patients with MDS showed that the majority had low lymphocyte counts in bone marrow. Using monoclonal antibodies (MoAbs) OKT3, OKT4 and OKT8 combined with SRBC rosettes, the authors found that there was a significant decrease of OKT3-defined Pan-T lymphocytes in peripheral blood. This reduction was primarily confined to the OKT4-defined helper subset, but there was a relative increase in the OKT8-defined suppressor subpopulation. As a result, the ration OKT4/OKT8 was reversed. The data of MLC test also showed abnormalities of cell-mediated immunity function in the patients. The significance of these observed changes in the pathogenesis of MDS was discussed.

In vitro studies on the nucleocapsid-associated RNA polymerase of wheat rosette stunt virus

RNA-dependent RNA polymerase activity was detected in both virion and nucleocapsid preparations of wheat rosette stunt virus, a plant rhabdovirus. The presence of nonionic detergent such as Nonidet P40 was essential for activity in reaction mixtures containing virions. The polymerase product was proved to be single-stranded RNA. By two-step controlled dissociation of the nucleocapsids, four subviral fractions (L protein, NS-N-RNA complex, NS protein, and N-RNA complex) were prepared. None of these fractions showed RNA polymerase activity when assayed individually. In experiments combining the various fractions, RNA synthesis was observed only when the L and NS proteins and the N-RNA complex were present in reaction mixtures.