bluuebunny/crossref_metadata_2025 huggingface dataset:
Total fluoride intake and urinary excretion in 4–year–old Iranian children residing in low-fluoride areas
Authors: Zohouri F. V. , Rugg-Gunn A. J.
Published: May 2019

Knowledge of levels of fluoride ingestion and excretion is important in planning optimum fluoride therapy for young children. In previous literature, it has been assumed that only about one-third of ingested fluoride is excreted in young children. The aims of the present study were (a) to measure total fluoride intake, urinary fluoride excretion and fluoride balance, and (b) to investigate the effect of air temperature on fluoride intake and urinary fluoride excretion, in young children. Children (4 years old) living in a city, a small town and rural areas of Fars province, Iran, where drinking water contained 0·30–0·39 mg F/l, were invited to participate. Selection of subjects was by random sampling of kindergartens or health centres. The children were surveyed twice, once in summer and once in winter. Diet was obtained by 3 d diaries with interview. Samples of most foods and drinks were analysed for fluoride content. Ingestion of fluoride from toothpaste was estimated for each child. Each child's urine was collected over 24 h and analysed for fluoride content. Seventy-eight of the 116 volunteers completed all aspects of the study, which was conducted in 1995–6. For all children, the mean fluoride ingestion from diet was 0·390 (sd 0·122) mg/d or 0·028 (sd 0·008) mg/kg body weight per d. Fluoride ingestion from diet was higher in summer and higher in rural areas. The mean ingestion of fluoride from all sources was 0·426 (sd 0·126) mg/d and the mean fluoride urinary excretion was 0·339 (sd 0·100) mg/d. The difference between ingestion and urinary excretion was +0·087 (sd 0·143) mg, equivalent to 80 % excretion. Faecal excretion was not estimated. The results indicate fluoride retention at 4 years to be much lower than previously assumed.
Estimation of the energy costs of locomotion in the Iberian pig(Sus mediterraneus)
Authors: Lachica M. , Aguilera J. F.
Published: May 2019

The energy cost of locomotion of four Iberian pigs was measured in two experiments conducted when the animals averaged 41·3 (se 0·1) kg (first experiment) and 84·1 (se 0·1) kg (second experiment). The heat production of the pigs was determined when standing or walking at a speed of 0·555 m/s on a treadmill enclosed in a confinement-type respiration chamber, on different slopes (-10·5, 0, and +10·5 % in the first experiment, and -5·25, 0 and +10·5 % in the second experiment). The energy costs of locomotion, estimated from the coefficients of linear regressions of heat production per kg body weight (BW) on distance travelled, were in the first experiment 2·99, 3·31 and 5·88 J/kg BW per m for -10·5, 0, and +10·5 % inclines respectively, and 2·56, 2·84 and 7·13 J/kg BW per m for -5·25, 0 and +10·5 % inclines respectively, in the second experiment. The net energy cost of locomotion on the level appeared to be independent of live weight, attaining a value of 2·98 J/kg BW per m. Also, it was found that within experiments the net energy cost of walking on negative slopes was similar to that for locomotion on the level, indicating that no energy was recovered on vertical descent. Mean values were 3·11 and 2·72 kJ/kg BW per m for the light and heavy pigs respectively. The energy cost of raising 1 kg BW one vertical metre was found to be 27·1 J/kg BW per m in the first experiment and 40·0 J/kg BW per m in the second experiment. Correspondingly, the calculated efficiency for upslope locomotion appeared to decline with increasing BW, resulting in average values of 36·2 and 24·5 %.
Interactions among the branched-chain amino acids and their effects on methionine utilization in growing pigs: effects on nitrogen retention and amino acid utilization
Authors: Langer Stefan , Fuller Malcolm F.
Published: May 2019

An experiment was conducted to investigate the effects of branched-chain amino acid (BCAA) interactions on their utilization by growing pigs and the effects of excessive amounts of BCAA (leucine, isoleucine, valine) on the utilization of methionine. A semipurified diet containing 100 g crude protein/kg with a balanced amino acid pattern was prepared using casein supplemented with free amino acids. Three further diets were made by reducing the concentration of methionine + cyst(e)ine, valine or isoleucine by 20 %. Each of these four diets was then supplemented with leucine (50 % excess) or a mixture of BCAA (50 % excess of each but excluding the limiting amino acid). All diets were isoenergetic and were made isonitrogenous by replacement of glutamic and aspartic acids. The twelve diets were given to twenty-four growing pigs (30–40 kg) in three periods according to a randomized block design. Each period lasted 8 d and N retention was measured during the last 5 d of each period. Reducing dietary methionine, valine or isoleucine reduced the utilization of N (N retained/N digested) by approximately 20 % (P< 0·05). Adding leucine to the isoleucine-limiting diet decreased the utilization of N by 9 % (P< 0·05). This was reversed by simultaneous addition of valine. Excess leucine in a valine-deficient diet did not significantly reduce N utilization. In methionine-limiting diets an excess of either leucine alone or of all three BCAA increased the utilization of N by 8 % (P< 0·05).
Evidence of progressive deterioration of renal function in rats exposed to a maternal low-protein dietin utero
Authors: Nwagwu Margaret O. , Cook Anna , Langley-Evans Simon C.
Published: May 2019

Intrauterine growth retardation associated with maternal undernutrition is proposed to play a significant role in the aetiology of hypertension and CHD. Animal experiments suggest that the kidney, which is extremely vulnerable to the adverse effects of growth-retarding factors, may play an important role in the prenatal programming of hypertension. Maintenance of renal haemodynamic functions following structural impairment in fetal life is proposed to require adaptations which raise systemic blood pressure and promote a more rapid progression to renal failure. Rats were fed on diets containing 180 g casein/kg (control) or 90 g casein/kg (low protein) during pregnancy. The offspring were studied in terms of blood pressure, creatinine clearance, blood urea N, plasma and urinary albumin, renal morphometry and metabolic activity at 4, 12 and 20 weeks of age. Blood pressure was elevated at all ages in the low-protein-exposed offspring, relative to control rats. Rats (4 weeks old) exposed to the low-protein diet had smaller kidneys which were shorter and wider than those of control animals. Creatinine clearance was significantly reduced in 4-week-old rats exposed to the low-protein diet. Renal morphometry and creatinine clearance at older ages were not influenced by prenatal diet. Blood urea N, urinary output and urinary albumin excretion were, however, significantly greater in low-protein-exposed rats than in control rats at 20 weeks of age. These findings are suggestive of a progressive deterioration of renal function in hypertensive rats exposed to mild maternal protein restriction during fetal life. This is consistent with the hypothesis that adaptations to maintain renal haemodynamic functions following impairment of fetal nephrogenesis result in an accelerated progression towards glomerulosclerosis and increased intrarenal pressures mediated by rising vascular resistance.
Effect of thyme oil and thymol dietary supplementation on the antioxidant status and fatty acid composition of the ageing rat brain
Authors: Youdim Kuresh A. , Deans Stanley G.
Published: May 2019

The present study measured changes in antioxidant enzyme activity in, and the phospholipid fatty acid composition of the ageing rat brain and tested whether dietary supplementation with thyme oil or thymol could provide beneficial effects. There were significant declines in superoxide dismutase (EC1.15.1.1) and glutathione peroxidase (EC1.11.1.9) activities and the total antioxidant status in the untreated rats with age, while thyme-oil- and thymol-fed rats maintained significantly higher antioxidant enzyme activities and total antioxidant status. The proportions of 18: 2n−6, 20: 1n−9, 22: 4n−6 and 22: 5n−3 in the brain phospholipids resulting from all three dietary treatments were significantly higher in 28-month-old rats than in 7-month-old rats. Only 20: 1n−9 levels in 28-month-old thyme-oil- and thymol-treated rats were significantly higher than in the age-matched control. The proportion of 22: 6n−3 in brain phospholipids, which declined with age in control rats, was also significantly higher in rats given either supplement. This latter finding is particularly important as optimum levels of 22: 6n−3 are required for normal brain function. These results highlight the potential benefit of thyme oil as a dietary antioxidant.
Decreasing dietary fat saturation lowers HDL-cholesterol and increases hepatic HDL binding in hamsters
Authors: Terpstra A. H. M. , van den Berg P. , Jansen H. , Beynen A. C. , van Tol A.
Published: May 2019

In order to study the mechanism by which increasing unsaturation of dietary fat lowers HDL-cholesterol levels, we studied various measures of HDL metabolism in hamsters fed with fats with different degrees of saturation. Hamsters were fed on a cholesterol-enriched (1 g/kg) semipurified diet containing 200 g/kg of maize oil, olive oil, or palm oil for 9 weeks. Increasing saturation of dietary fat resulted in increasing concentrations of total plasma cholesterol (4·29 (SD 0·51), 5·30 (sd 0·67) and 5·58 (sd 0·76) mmol/l respectively,n12) and HDL-cholesterol (3·31 (sd 0·50), 3·91 (sd 0·12) and 3·97 (sd 0·43) mmol/l) and these concentrations were significantly higher (P< 0·05) in the palm-oil and olive-oil-fed hamsters compared with the maize-oil group. Total plasma triacylglycerol levels also increased with increasing fat saturation (1·01 (sd 0·59), 1·56 (sd 0·65) and 2·75 (sd 1·03) mmol/l) and were significantly higher (P< 0·05) in the palm-oil group compared with the olive-oil and maize-oil-fed hamsters. The three diets did not have differential effects on plasma activity levels of lecithin: cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP). Levels of phospholipid transfer protein (PLTP) tended to be higher with increasing fat saturation but this effect was not significant. The capacity of liver membranes to bind human HDL3was significantly higher (P< 0·05) in the hamsters fed with maize oil (810 (sd 100) ng HDL3protein/mg membrane protein,n4) compared with those fed on palm oil (655 (sd 56) ng/mg), whereas the olive-oil group had intermediate values (674 (sd 26) ng/mg). The affinity of HDL3for the binding sites was not affected by the type of dietary fat. Hepatic lipase (EC3.1.1.3) activity, measured in liver homogenates, increased with increasing fat saturation. We conclude that dietary maize oil, when compared with either olive oil or palm oil, may lower HDL-cholesterol concentrations by enhancing HDL binding to liver membranes.
Accelerated thymus involution in magnesium-deficient rats is related to enhanced apoptosis and sensitivity to oxidative stress
Authors: Malpuech-Brugère Corinne , Nowacki Wojciech , Gueux Elyett , Kuryszko Jan , Rock Edmond , Rayssiguier Yves , Mazur Andrzej
Published: May 2019

Experimental Mg deficiency leads to alterations in the immune response. Reduction of thymus weight and histological changes were previously observed in Mg-deficient rats after several weeks on a deficient diet, suggesting that functions of this immune organ may be affected by Mg deficiency. More recently, changes in the immune system during early Mg deficiency were shown. Thus, in the present study we examined modifications in the thymus during the early stages of Mg deficiency in weanling rats. From our results, it appears that Mg deficiency accelerates thymus involution. The assessment of apoptosis (enumeration of apoptotic cells on the basis of morphological criteria and intranucleosomal degradation of genomic DNA) showed greater values in thymuses from Mg-deficient rats as compared with controls. This was observed very early, since a significant difference was shown on the second day of deficiency, before reduced weight of thymus, which was recorded in the later period. These results indicate the relationship of accelerated thymus involution with an active process of cell death. Mg deficiency led to histological changes in the thymus. In the early stage of deficiency (second day) the presence of inflammatory cells was shown, suggesting that the inflammatory process was already occurring in the tissue studied. Later (eighth day) an increased proportion of epithelial reticular cells in the cortex was shown, indicating a remodelling process occurring in this period. Enhanced susceptibility to peroxidation also occurred very early during Mg deficiency. It may be hypothesized that disturbances in Mg status of short duration could have cellular effects with various deleterious consequences.
Protein restriction during early development enhances insulin responsiveness but selectively impairs sensitivity to insulin at low concentrations in white adipose tissue during a later pregnancy
Authors: Holness M. J. , Fryer L. G. D. , Sugden M. C.
Published: May 2019

Poor early nutrition may elicit long-term detrimental effects on adult health, including susceptibility to non-insulin-dependent diabetes mellitus. We investigated the impact of moderate maternal protein restriction during pregnancy and lactation on the action of insulin on adipocyte glucose uptake in female offspring during their own pregnancies. Offspring of dams provided with diets containing either 200 g protein/kg or 80 g protein/kg during pregnancy and lactation (termed C and EPR groups respectively) were weaned on to 200 g protein/kg diet at 24 d of age. At 9–12 weeks of age both groups were time-mated and studied at day 19 of gestation. Rates of glucose utilization (assessed using the 2-deoxy-d-- [1-3H- ]glucose technique) measured in five distinct adipose tissue depots (parametrial (PM), mesenteric (MES), perirenal (PR), subcutaneous (SC), interscapular (IS))in vivoin the post-absorptive state were consistently lower in early-protein-restricted (EPR) pregnant rats compared with control (C) pregnant rats. In C pregnant rats, insulin significantly increased glucose utilization only in the IS depot. In contrast, significantly increased glucose utilization rates in response to hyperinsulinaemia were evident in all five adipose-tissue depots of the EPR pregnant group. Consequently, glucose utilization rates in PM and SC depots during hyperinsulinaemia were significantly higher in EPR pregnant rats compared with C pregnant rats. Adipocytes were isolated from PM and MES depots to determine whether altered responses to insulinin vivowere retainedin vitro. Rates of insulin-stimulated glucose uptake at sub-maximal (15 μU/ml) and maximal (15 mU/ml) insulin concentrations were significantly higher in both MES and PM adipocytes from EPR pregnant rats, but the sensitivity of glucose uptake to insulin at low concentrations was blunted compared with adipocytes from C pregnant rats. The results demonstrate that early protein restriction enhances the capacity for adipocyte glucose uptake at high insulin concentrations, but dampens the response to insulin at low physiological concentrations.
Ileal amino acid digestibilities in pigs of barley-based diets with inclusion of lucerne (Medicago sativa), white clover (Trifolium repens), red clover (Trifolium pratense) or perennial ryegrass (Lolium perenne)
Authors: Reverter M. , Lundh T. , Lindberg J. E.
Published: May 2019

Two experiments were performed with post-valve T-cannulated growing pigs, using five animals in each experiment in a change-over design to evaluate the effect of inclusion of four different dried forage meals on ileal crude protein (CP) and amino acid (AA) digestibilities. The control diets (C1 and C2) were barley-based and the experimental diets were formulated by replacing the barley with 100 or 200 g/kg of either lucerne (Medicago sativa) or white clover (Trifolium repens) meal in Expt 1 and red clover (Trifolium pratense) or perennial ryegrass (Lolium perenne) meal in Expt 2. A decrease (P< 0·05) in the apparent ileal digestibility of CP and most of the essential and nonessential AA was found with the inclusion of lucerne, white clover and perennial ryegrass meal in the barley-based diets. When red clover meal was included, only the apparent ileal digestibilities of CP, leucine, phenylalanine, tyrosine and glutamic acid were found to decrease (P< 0·05). The estimated apparent ileal digestibilities of most essential AA in the forage meals were lower than in the barley-based diets. The ileal flow of glucosamine and ornithine was found to increase (P< 0·05) with increasing proportion of fibre in the diet, suggesting an increase in endogenous N secretions and small-intestinal microbial activity. With the minor changes found for ileal essential AA digestibilities with forage meal inclusion in the diet the present data confirm the potential of forage meals as a source of protein in pig diets.
Effect of diet composition and ration size on key enzyme activities of glycolysis–gluconeogenesis, the pentose phosphate pathway and amino acid metabolism in liver of gilthead sea bream (Sparus aurata)
Authors: Metón I. , Mediavilla D. , Caseras A. , Cantó E. , Fernández F. , Baanante I. V.
Published: May 2019

The effects of diet composition and ration size on the activities of key enzymes involved in intermediary metabolism were studied in the liver of gilthead sea bream (Sparus aurata). High-carbohydrate, low-protein diets stimulated 6-phosphofructo 1-kinase (EC2.7.1.11), pyruvate kinase (EC2.7.1.40), glucose-6-phosphate dehydrogenase (EC1.1.1.49) and 6-phosphogluconate dehydrogenase (EC1.1.1.44) enzyme activities, while they decreased alanine aminotransferase (EC2.6.1.2) activity. A high degree of correlation was found between food ration size and the activity of the enzymes 6-phosphofructo 1-kinase, pyruvate kinase, glucose-6-phosphate dehydrogenase (positive correlations) and fructose-1,6-bisphosphatase (EC3.1.3.11) (negative correlation). These correlations matched well with the high correlation also found between ration size and growth rate in starved fish refed for 22 d. Limited feeding (5 g/kg body weight) for 22 d decreased the activities of the key enzymes for glycolysis and lipogenesis, and alanine aminotransferase activity. The findings presented here indicate a high level of metabolic adaptation to both diet type and ration size. In particular, adaptation of enzyme activities to the consumption of a diet with a high carbohydrate level suggests that a carnivorous fish likeSparus auratacan tolerate partial replacement of protein by carbohydrate in the commercial diets supplied in culture. The relationship between enzyme activities, ration size and fish growth indicates that the enzymes quickly respond to dietary manipulations of cultured fish.
Dietary restriction of energy and sugar results in a reduction in human cytochrome P450 2E1 activity
Authors: Leclercq Isabelle , Horsmans Yves , Desager Jean-Pierre , Pauwels Stanislas , Geubel André P.
Published: May 2019

Dietary habits are often considered as a pathogenic factor for fatty liver. The impact of dietary intake and steatosis on drug metabolism remains poorly investigated. Our aim was to assess the effect of dietary intake on in vivo cytochrome P450 (CYP) activities in eleven patients with abnormal liver function tests potentially due to fatty liver and associated with a high-sugar diet. Liver function tests, liver volume, aminopyrine breath test (ABT) and chlorzoxazone (CZ) pharmacokinetics (area under the curve, AUC) which are known to reflect CYP2E1 activity were evaluated before and after 2 months restriction of dietary sugar intake. Features at inclusion were an increased BMI (30·3 (sd 3·2) kg/m2), high hepatic volume (1·96 (sd 0·48) litres), hyperechogenic liver parenchyma, elevated liver enzyme activities (alanine aminotransferase (EC 2.6.1.2) 58·6 (sd 17·4) IU/l with alanine aminotransferase : aspartate aminotransferase (EC 2.6.1.1) ratio > 1), together with a normal ABT value (0·68 (sd 0·21) % specific activity of administered dose of [14C]aminopyrine in breath after 1 h) and a high CYP2E1 activity (CZ AUC 20·3 (sd 7·1) μg/ml per h). A dietary sugar restriction was prescribed. On the basis of repeated interviews by the same dietitian, unaware of any clinical and biochemical data, six patients remained compliant to the diet and exhibited reductions in BMI (P < 0·001), serum alanine aminotransferase (P = 0·008), liver volume (P = 0·002) and CYP2E1 activity (P = 0·007), a significant increase in ABT (P < 0·001) together with the disappearance of liver hyperechogenicity at ultrasound. In contrast, the five non-compliant patients did not show any significant change in any of these variables. In conclusion, CYP2E1 activity is induced in patients with perturbations of liver function tests potentially due to fatty liver. In these patients, effective dietary sugar restriction is associated with a reduction in liver volume, a reduction in CYP2E1 activity and an increased aminopyrine metabolism rate.
Involvement of lipoic acid in plasma metabolites, hepatic oxygen consumption, and metabolic response to a β-agonist in broiler chickens
Authors: Hamano Yoshio , Sugawara Sanae , Kamota Yoko , Nagai Emi
Published: May 2019

The present study was conducted to determine the role of α-lipoic acid (LA) in plasma metabolites, hepatic O2 consumption, and β-adrenergic response in broilers. In Expt 1, 12-d-old female broiler chicks were divided into three dietary groups and fed on diets with or without LA (5 or 50 mg/kg) until 4 or 6 weeks of age, as a 2 × 3 factorial arrangement. The dietary LA had no effect on growth rates (body weight, abdominal fat, breast muscle, and liver). The higher level of LA increased plasma non-esterified fatty acid and decreased plasma triacylglycerol concentrations only at 6 weeks of age. A 42 % increase in hepatic respiration was observed in the 4-week-old chickens given 50 mg LA/kg diet. In Expt 2, 3-d-old female broiler chicks were treated with or without dietary LA at 50 mg/kg. At 30 and 31 d old, isoproterenol (2 mg/kg body weight per h) was continuously infused into a wing vein for 2 h, and changes in plasma glucose, triacylglycerol, and non-esterified fatty acid concentrations were analysed. Isoproterenol increased plasma glucose over basal levels maximally at 60 min. Furthermore, the glucose increase in the LA-treated chickens was 35% greater than that of the controls at this time. Plasma non-esterified fatty acid and triacylglycerol concentrations were decreased by the isoproterenol infusion, regardless of LA administration. Therefore, the present study suggests that dietary LA has repartitioning effects on energy metabolism in chickens (although this depends on age-related metabolic state) and is a possible facilitator in the β-adrenergic response of plasma glucose to a β-agonist.
The Child and the Beast: Fighting Violence in Ancient Christianity
Authors: Bovon François
Published: May 2019

Popular nature programs, such as the cable-television programWild Discovery, are both appealing and frightening because they confront the audience with acts of pure violence that follow the natural law of the jungle and the harsh imperative of nature's food chain. Viewers are enthralled watching the leopard catch its prey: such is the power of violence.
The Oldest Original Synagogue Building in the Diaspora: A Response to L. Michael White
Authors: Runesson Anders
Published: May 2019

In 1997, the Harvard Theological Review published an article written by L. Michael White in which he “presents and analyzes evidence for the social location and organization of Jewish groups in the environs of Rome, specifically from the port city of Ostia” during the first centuries CE. White draws from two sources in his examination: archaeological remains of the Ostia synagogue and rather scanty—but important—epigraphical material, the Mindius Faustus and the Gaius Julius Justus inscriptions. White's study is the most extensive discussion of the archaeological evidence in English since the excavator, Maria Floriani Squarciapino, presented her preliminary reports from the excavations of the synagogue in the early 1960s. Despite the great interest that the synagogue at Ostia aroused when it was unearthed and excavated during two campaigns in 1961 and 1962, it has since been neglected by scholars.
Black Power Children's Literature: Julius Lester and Black Power
Authors: BATHO NICK
Published: May 2019

This article examines a small selection of children's books by Julius Lester, a black power activist, considering them in the context of the black power movement. Lester is frequently cited for his activism and polemical works on black power but no study of his works for children has yet been published. The works considered in this article provide an example of how children's books during this period reflected aspects of black power ideology, language and imagery. Whilst books for black children in the USA had a long history of trying to instil racial pride and knowledge of African American history, these efforts were nevertheless restricted for various reasons. This article argues that it was the black power movement that provided a context in which books directed at black children could flourish. Librarians, activists, educators and publishers now engaged in providing literature for black children in a more comprehensive and directed way than before. Within this context, authors like Julius Lester could write books that celebrated African American history and folklore and could at the same time address issues of racial tension and white cultural hegemony.
Stratigraphic and Paleogeographic Significance of An Upper Ordovician Acritarch Flora from the Maquoketa Shale, Northeastern Missouri, U.S.A.
Authors: Wicander Reed , Playford Geoffrey , Robertson Eddie B.
Published: May 2019

A well-preserved and moderately diverse acritarch assemblage was recovered from the upper Ordovician Maquoketa Shale of northeastern Missouri. Based on graptolite and conodont evidence, the Maquoketa in northeastern Missouri is considered Richmondian (=Ashgill) in age.

The acritarch assemblage comprises 28 species, distributed among 17 genera including two new genera,CaelatosphaeraandStictosoma.There are 11 new species,Baltisphaeridium adiastaltum, Caelatosphaera verminosa(type species),Dorsennidium undosum, Elektoriskos aktinotos, Lophosphaeridium acinatum, L. varum, Micrhystridium hirticulum, M. prolixum, Peteinosphaeridium accinctulum, P. septuosum, andStictosoma gemmata(type species); together with two species similar to previously named species and three species left in open nomenclature. Cosmopolitan and stratigraphically important species identified includeBaltisphaeridium perclarumLoeblich and Tappan, 1978;Cheleutochroasp. cf.C. diaphorosaTurner, 1984;Dorsennidium hamii(Loeblich, 1970) Sarjeant and Stancliffe, 1994;Excultibrachium concinnumLoeblich and Tappan, 1978;Orthosphaeridium insculptumLoeblich, 1970;O. rectangulare(Eisenack, 1963) Eisenack, 1968, andVillosacapsula setosapellicula(Loeblich, 1970) Loeblich and Tappan, 1976.Polygonium gracileVavrdová, 1966 emend. Sarjeant and Stancliffe, 1994 andMicrhystridium hirticulumnew species dominate the assemblage, followed byDorsennidium undosumnew species,Baltisphaeridium oligopsakiumLoeblich and Tappan, 1978,Veryhachiumsp. cf.V. oklahomenseLoeblich, 1970,Peteinosphaeridium accinctulumnew species, andLophosphaeridium acinatumnew species. Additionally, the palynoflora contains chitinozoans, scolecodonts, cryptospores, and the enigmatic palynomorphGloeocapsomorpha priscaZalessky, 1917 emend. Foster, Reed, and Wicander, 1989.

Paleontologic-palynologic and sedimentologic evidence indicates that the Maquoketa Shale at the two studied localities accumulated under low energy, somewhat offshore, and unrestricted marine conditions. The present Maquoketa Shale acritarch palynoflora shows greatest similarity to those of the Sylvan Shale (Ashgill; Richmondian) of Oklahoma and the Maquoketa Shale (Caradoc and Ashgill) of Kansas. Whereas there are some cosmopolitan acritarch species present in the Maquoketa Shale, its palynoflora shows no pronounced similarity with age-equivalent acritarch suites from outside of North America.
Analysis of parasite host-switching: limitations on the use of phylogenies
Authors: Jackson J. A.
Published: May 2019

Even the most generalist parasites usually occur in only a subset of potential host species, a tendency which reflects overriding environmental constraints on their distributions in nature. The periodic shifting of these limitations represented by host-switches may have been an important process in the evolution of many host-parasite assemblages. To study such events, however, it must first be established where and when they have occurred. Past host-switches within a group of parasites are usually inferred from a comparison of the parasite phylogeny with that of the hosts. Congruence between the phylogenies is often attributed to a history of association by descent with cospeciation, and incongruence to host-switching or extinction in ‘duplicated’ parasite lineages (which diverged without a corresponding branching of the host tree). The inference of host-switching from incongrucnt patterns is discussed. Difficulties arise because incongruence can frequently be explained by different combinations of biologically distinct events whose relative probabilities are uncertain. Also, the models of host parasite relationships implicit in historical reconstructions may often not allow for plausible sources of incongruence other than host-switching or duplication/extinction, or for the possibility that colonization could, in some circumstances, be disguised by ‘false’ congruence.
The cost of counting and identifying weed seeds and seedlings
Authors: Wiles Lori J. , Schweizer Edward E.
Published: May 2019

Bioeconomic weed management models help growers achieve appropriate weed management with less herbicide by matching management to the weed population in a field. Growers, however, will not use bioeconomic models unless cost-effective methods to sample their weed populations are identified. Counting and identifying seeds and seedlings is the most time-consuming and costly part of sampling weed populations. The time required for this process was investigated and modeled as a first step in developing sampling plans for growers using WEEDCAM, a bioeconomic model for weed management inZea maysL. in Colorado. The time required to count and identify seeds or seedlings was recorded for 9,405 soil cores (5 cm in diameter and 10 cm deep) and 9,726 quadrats (18-cm band over 1.52 m of crop row) collected or examined in eight corn fields in eastern Colorado. The time required to count and identify seeds was best described using a log-linear regression with time increasing with the number of seeds and species and the amount of sand in the core. The average cost of determining there are no seeds in a core is $1.07 for a core from a field with 37% sand and $4.32 if the field has 88% sand. The average cost of counting and identifying 36 seeds of four species is $2.70 and $10.88 for cores with 37 and 88% sand, respectively. The time required to count and identify seedlings was best described using a log-linear regression with time increasing with the number of seedlings and species. Classifying seedlings as grass or broadleaf did not improve the model. The average cost of determining that a quadrat is weed-free is $0.02. The average cost of counting and identifying 37 seedlings is $0.05, $0.07, $0.19, and $0.26 per quadrat for 1, 2, 4, and 6 species, respectively. The cost of identifying seeds and seedlings in eastern Colorado Z.maysfields to use WEEDCAM is estimated as $2.71 per core for the seed bank and $0.08 per quadrat for seedlings.
Full-season interference ofIpomoea hederaceawithGossypium hirsutum
Authors: Wood Mark L. , Murray Don S. , Westerman R. Brent , Verhalen Laval M. , Claypool P. L.
Published: May 2019

Four field experiments were conducted to measure the effects of sevenIpomoea hederacea(L.) Jacq. densities onGossypium hirsutumL. lint yield, stripper-harvest efficiency, and fiber properties. The seven densities were 0, 2, 4, 6, 8, 10, and 12 weeds 10 m−1of row. Data were used to develop prediction models to compare with those previously constructed that used fewer experiments and fewer weed densities in this range.Gossypium hirsutumlint yield in kilograms per hectare and as a percentage of the weed-free control best fit a linear regression model.Gossypium hirsutumlint yield reductions for each increase of one weed 10 m−1of row ranged from 30.7 to 36.2 kg ha−1at Chickasha and from 35.4 to 36.4 kg ha−1at Perkins. Lint yield reductions for each weed 10 m−1of row ranged from 3.8 to 6.9% at Chickasha and from 3.9 to 6.0% at Perkins. All plots could be mechanically stripper harvested, except for the 12-weed density at Chickasha in 1994 and the 10- and 12-weed densities at Perkins in 1996. Harvest efficiencies were not significantly different in any experiment. The only fiber properties to display significant differences were micronaire and strength at Chickasha in 1994. Prediction models calculated herein were highly similar to those previously constructed.
Absorption, fate, and soil activity of quinclorac in field bindweed (Convolvulus arvensis)
Authors: Enloe Stephen F. , Nissen Scott J. , Westra Philip
Published: May 2019

Laboratory and greenhouse experiments were conducted to examine the absorption and fate of quinclorac in field bindweed and to assess the importance of quinclorac soil activity for field bindweed control. No foliar absorption of14C-quinclorac occurred when applied alone, but absorption increased to 24% when quinclorac was applied with 2,4-D, 28% urea ammonium nitrate (UAN), and methylated seed oil (MSO). Quinclorac translocation in field bindweed was limited, as < 18% of the total amount of absorbed radiolabeled material translocated out of the treated leaves 168 hours after treatment (HAT). Quinclorac metabolism in the treated leaves was minimal; 95% of the recovered14Cwas intact herbicide 168 HAT. Quinclorac soil activity on field bindweed was demonstrated in preemergence and soil subsurface applications. Preemergence application of 35, 70, 140, or 280 g ha−-1quinclorac reduced field bindweed shoot growth. Field bindweed shoots exhibited auxinic herbicide symptoms at all quinclorac rates. Subsurface layering of quinclorac below the root system at rates of 35 and 280 g ha−-1also reduced shoot and root growth. Both herbicide rates induced malformation in root structure with a proliferation of lateral branching, swollen and fused root tips, and malformed root buds. Shoot growth from surviving roots replanted in untreated media was also reduced in both herbicide treatments. These findings suggest quinclorac soil activity may be important for field bindweed control.
Modeling germination and seedling elongation of common lambsquarters (Chenopodium album)
Authors: Roman Erivelton S. , Thomas A. Gordon , Murphy Stephen D. , Swanton Clarence J.
Published: May 2019

The ability to predict time of weed seedling emergence relative to the crop is an important component of a mechanistic model describing weed and crop competition. In this paper, we hypothesized that the process of germination could be described by the interaction of temperature and water potential and that the rate of seedling shoot and radicle elongation vary as a function of temperature. To test these hypotheses, incubator studies were conducted using seeds and seedlings of common lambsquarters. Probit analysis was used to account for variation in cardinal temperatures and base water potentials and to develop parameters for a new mathematical model that describes seed germination and shoot and radicle elongation in terms of hydrothermal time and temperature, respectively. This hydrothermal time model describes the phenology of seed germination using a single curve, generated from the relationship of temperature and water potential.
Cross-resistance of primisulfuron-resistant Bromus tectorum L. (downy brome) to sulfosulfuron
Authors: Mallory-Smith Carol , Hendrickson Paul , Mueller-Warrant George
Published: May 2019

A Bromus tectorum L. (downy brome) biotype with cross-resistance to sulfosulfuron has been identified. The resistant biotype was selected with primisulfuron in Poa pratensis L. (Kentucky bluegrass) plots near Madras, OR. The plots received two treatments of 20 g ai ha−1 primisulfuron in the fall of 1993, 1994, and 1995. In 1995, control of B. tectorum decreased and greenhouse studies confirmed that the biotype was resistant to primisulfuron. Cross-resistance to sulfosulfuron also was confirmed in greenhouse studies. Metabolism of sulfosulfuron rather than an insensitive site of action is the likely cause of the cross-resistance.
The influence of surfactant and nitrogen on foliar absorption of MON 37500
Authors: Miller Patrick A. , Westra Philip , Nissen Scott J.
Published: May 2019

Laboratory experiments were conducted to assess the influence of surfactants applied with or without nitrogen on MON 37500 foliar absorption byBromus tectorum, Bromus japonicus, Aegilops cylindrica, Triticum aestivum, Chorispora tenella, andLactuca serriola.MON 37500 absorption inB. tectorumandB. japonicusincreased from 40% 24 h after treatment (HAT) to 48% 48 HAT, averaged across surfactants with no added nitrogen. Averaged across nitrogen source and species, nonionic surfactant, ethylated seed oil, and organosilicate provided comparable enhancement of MON 37500 absorption (56 to 68%), whereas crop oil concentrate provided only 27 to 29% absorption under the same conditions. Averaged across species and surfactant class, urea ammonium nitrate had the greatest effect on MON 37500 absorption (68%), compared to ammonium sulfate (59%) or no nitrogen (40%). Nitrogen, regardless of the type, significantly improved foliar absorption of MON 37500. MON 37500 absorption by species was 71, 63, 57, 57, 49, and 38% inC. tenella, B. japonicus, T. aestivum, A. cylindrica, B. tectorum, andL. serriola, respectively, when averaged across surfactants and nitrogen. Densely pubescentB. japonicusleaves did not retain significant amounts of MON 37500 following a primary leaf wash.
Estimates of physiological determinants forAmaranthus retroflexus
Authors: Knezevic Stevan Z. , Horak Michael J. , Vanderlip Richard L.
Published: May 2019

Redroot pigweed is a troublesome weed in the sorghum-growing regions of North America. In 1994 and 1995, field studies were conducted at two locations near Manhattan, KS, to determine the influence of redroot pigweed density and environmental conditions on physiological determinants of redroot pigweed growth: duration of plant growth, light interception, radiation-use efficiency, and dry matter partitioning. In addition, specific leaf area was determined. Redroot pigweed was seeded at monoculture densities of 2, 4, and 12 plants m−1of row each year at each location. Duration of redroot pigweed growth was not influenced by plant density. Light interception was defined as a simple exponential function of leaf area index. Specific leaf area did not change over the season and averaged 135 cm2g−1. Partitioning of redroot pigweed dry matter was not influenced by plant density or environmental conditions but did not change within vegetative and reproductive stages. Radiation-use efficiency was not influenced by redroot pigweed density; the most reliable estimate was 1.74 g dry matter MJ−1of intercepted photosynthetically active radiation. Physiological determinants described were not affected by redroot pigweed density or environmental conditions and therefore provide a starting point for the development of a redroot pigweed growth module. The module could be coupled with available crop growth models (e.g., the sorghum growth model SORKAM) to simulate redroot pigweed–sorghum competition.
Molecular markers indicate intraspecific variation in the control ofEchinochloaspp. with quinclorac
Authors: Lopez-Martinez Nuria , Salva Antonio Pujadas , Finch Robert P. , Marshall George , De Prado Rafael
Published: May 2019

Some species of the genusEchinochloaare troublesome weeds in rice fields. The taxonomy of this genus leads to confusion in many cases due to its great morphological diversity. Because of the differential sensitivity to the herbicide quinclorac shown byEchinochloaspp., it was necessary to assess the botanical and molecular characterization of this weed.Echinochloa colonum, E. oryzoides, andE. oryzicolawere very susceptible to quinclorac treatment; by contrast,E. crus-galliandE. hispidulashowed some degree of natural tolerance. Physiological and molecular results agreed with the botanical classification of the genusEchinochloain Flora Europea. The importance of these results is due to yield losses produced by the infestation ofEchinochloaand the need for a strategy forEchinochloamanagement depending on the distribution of theEchinochloaspecies.
Near-isogenic lines forTriticum aestivumheight and crop competitiveness
Authors: Seefeldt Steven S. , Ogg Alex G. , Hou Yuesheng
Published: May 2019

Near isolines of ‘Nugaines’ winterTriticum aestivumthat differed in height were planted with and withoutAegilops cylindricato determine the effect of plant height on competition againstA. cylindrica.The isolines had either reduced height geneRht1,Rht2,Rht1plusRht2, or neitherRhtgenes and averaged 79, 77, 51, and 101 cm tall, respectively, when grown with or without competition fromA. cylindrica.Plants with fewer reduced height genes had the faster rates of height and weight gain, which are important traits for enhanced competitiveness. When growing in competition withA. cylindrica, the shortest isoline allowed the greatest amount ofA. cylindricaseed production but did not have the lowestT. aestivumyield. However, when compared to theA. cylindrica-free control, the shortest isoline had the greatest percent yield loss. The tallest isoline reducedA. cylindricaseed production the most, andT. aestivumyield reduction due toA. cylindricaon a percent basis was the least when averaged over 2 yr. When competing againstA. cylindrica, the tallest isoline did not always have the largest yield and yield parameters, and the shortest isoline did not always have the smallest yield and yield parameters. There is a cost to theT. aestivumplant to produce extra stem biomass that may reduce yield potential of taller plants and reduce the advantage gained by being taller than the surrounding weeds.
Cyperus esculentusinterference inCucumis sativus
Authors: Johnson W. Carroll , Mullinix Benjamin G.
Published: May 2019

Field studies were conducted near Tifton, GA, from 1995 to 1997 to measureCyperus esculentus(yellow nutsedge) interference with ‘Fancipack’Cucumis sativus(cucumber) using a response prediction experiment with a natural infestation ofC. esculentus. Cucumis sativuswas direct-seeded each year. Plots (1.8 by 1.8 m) were established immediately after crop emergence.Cyperus esculentusplants were counted 2 wk after crop emergence in each plot, at which time four weed-free plots were randomly established.C. esculentusdensities ranged from 0 to 955 plants m−2. Total yield, plant biomass, andC. sativusstand were regressed againstC. esculentusdensity and biomass. Regression analysis showed a 5% reduction inC. sativusyield with aC esculentusinfestation of approximately 15 plants m−2. A uniformC. sativusstand maximized its competitive ability and minimized interference fromC. esculentus. Cyperus esculentuswas more competitive and reducedC. sativusyields whenC. sativusstands were low and nonuniform.
Effect ofGalerucellaspp. on survival of purple loosestrife (Lythrum salicaria) roots and crowns
Authors: Katovich Elizabeth J. Stamm , Becker Roger L. , Ragsdale David W.
Published: May 2019

Starch levels, used as a measure of plant stress, were not consistently reduced in root or crown tissue of purple loosestrife plants after 2 yr of severeGalerucella calmariensisorGalerucella pusilla(Coleoptera: Chrysomelidae) defoliation. Early in the season, defoliation fromGalerucellaspp. approached 100%, but the majority ofLythrum salicariaplants regrew by the end of August, resulting in an average reduction of 81% of the aboveground biomass compared to the control. The stress imposed byGalerucellaspp. defoliation was less than that achieved from more severe stress imposed by mechanical shoot clipping at 2- or 4-wk intervals from June to October. Both shoot-clipping treatments killed the majority of plants after one growing season.Galerucellaspp. feeding reduced plant stature, which may reduce competitiveness. However, considering the extensive carbohydrate reserves present in the large woody crowns ofLythrum salicaria, it will require in excess of 2 yr of consistent, severe leaf defoliation to cause plant mortality. A combination of stresses, such as winter crown injury, or other biological control agents in addition toGalerucellaleaf defoliation may be required for plant mortality.
Genetic variability for resistance to trifluralin inZea mays
Authors: Landi Pierangelo , Frascaroli Elisabetta , Giuliani Marcella M.
Published: May 2019

Soil carryover of the herbicide trifluralin can injureZea mays.Therefore, the development of resistant hybrids can be an important breeding objective. This research was conducted to study the genetic variability for trifluralin resistance inZ. mays, the effects of genes controlling resistance, and the seed lipid content of resistant (R) and susceptible (S) inbreds. Twenty inbreds were tested under greenhouse conditions at three trifluralin rates (0, 12.5, and 125 g ai ha−1). Lo1067 was the most resistant, and A632 was the most susceptible inbred. Hybrids among R and S inbreds were tested, along with their parents, under greenhouse conditions (using the same three rates) and in the field (at 0, 0.4, and 0.8 kg ai ha−1). Under both greenhouse and field conditions, inbreds R were more resistant than S. Hybrids R × R were more resistant than S × S, indicating that additive effects were important. Hybrids R × S and S × R did not significantly differ, indicating that reciprocal effects were not important. On average, hybrids R × S and S × R were intermediate between R × R and S × S, suggesting that nonadditive effects were negligible. The difference between the mean across hybrids and the mean across parents (further estimating the importance of nonadditive effects) was significant only for parameters investigated in the greenhouse. Greenhouse data were correlated with field data, but the coefficients of determination were < 50%. The ability to predict hybrid resistance on the basis of parental mean was higher in the greenhouse (r2= 0.78) than in the field (r2= 0.47). R and S inbreds also differed in seed lipid content, but correlations were negligible with greenhouse and field data. Data indicated the presence of genetic variability for trifluralin resistance, that additive effects were prevailing, and that the resistance level was not related to seed lipid content.
A detoxification gene in transgenicNicotiana tabacumconfers 2,4-D tolerance
Authors: Last David I. , Llewellyn Danny J.
Published: May 2019

TransgenicNicotiana tabacumwith tolerance to 2,4-D has previously been produced using a bacterial 2,4-D-dioxygenase gene (tfdA) driven by the 35S promoter of cauliflower mosaic virus. Using promoters from thePisum sativumplastocyanin gene (petE) and anArabidopsis thalianahistone gene (H4A), we demonstrate that similar protection from 2,4-D can be obtained in transgenicN. tabacumby targeting expression oftfdAto either meristematic tissues or chloroplast-containing tissues. As with the 35S promoter constructs, the plants are tolerant but not completely resistant; very young seedlings in particular are only slightly protected. However, the levels of tolerance observed could offer a useful degree of protection from accidental spray drift.