The Importance of Comparative Growth Rates in Determining the Canopy Composition of Tasmanian Rainforest

1995 ◽  
Vol 43 (3) ◽  
pp. 243 ◽  
Author(s):  
J Read
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Forest Stands ◽  
Lower Growth ◽  
Naturally Occurring ◽  
Significant Difference ◽  
Pot Trials ◽  
Canopy Composition ◽  
Study Sites

Growth rates of the rainforest canopy species Atherosperma moschatum Labill., Eucryphia lucida (Labill.) Baill., Nothofagus cunninghamii (Hook.) Oerst., Athrotaxis selaginoides D.Don and Phyllocladus aspleniifolius (Labill.) Hook.f. were measured in naturally-occurring seedlings and in seedlings grown in glasshouse pot trials. The highest field growth rates were recorded in N. cunninghamii on lowland sites on fertile, well-drained soils. On poorer soils, growth rates of N. cunninghamii were lower and there was little difference in growth rates between species. On the most acidic and probably infertile soil, the growth rate of P. aspleniifolius was 1.4 times higher than that of N. cunninghamii, although not significantly different at the 95% level. Similar trends in growth rates were recorded in pot trials. High growth rates were recorded in N. cunninghamii and E. lucida on fertile, well-drained soils, with generally lower growth rates in A. moschatum, P. aspleniifolius and A. selaginoides. No significant difference in growth rate was recorded among N. cunninghamii, E. lucida, A. moschatum and P. aspleniifolius when grown in poor soils or in low nutrient treatments. The trends in comparative growth rates correlate with the measured canopy composition of the study sites. Nothofagus cunninghamii dominates forest stands on sites where it has a clearly superior growth rate compared with co-occurring light-demanding species. Mixed canopies occur on sites where there is little or no difference between species' growth rates. However, not all patterns of canopy dominance can be explained by comparative growth rates alone. For example, P. aspleniifolius commonly dominates forest stands at low to mid-altitude where growth rates of all species are very low, but without necessarily a higher growth rate in P. aspleniifolius than in co-occurring species. The results of the growth rate studies are integrated with some other aspects of the biology of these species in a discussion of the mechanisms determining canopy composition of Tasmanian rainforests.

scholarly journals Growth Rate-Dependent Control in Enterococcus faecalis: Effects on the Transcriptome and Proteome, and Strong Regulation of Lactate Dehydrogenase

2011 ◽  
Vol 78 (1) ◽  
pp. 170-176 ◽  
Author(s):  
Ibrahim Mehmeti ◽  
Ellen M. Faergestad ◽  
Martijn Bekker ◽  
Lars Snipen ◽  
Ingolf F. Nes ◽  
...  
Keyword(s):  
Growth Rate ◽  
Lactate Dehydrogenase ◽  
Enterococcus Faecalis ◽  
Growth Rates ◽  
Posttranscriptional Regulation ◽  
High Growth ◽  
Regulation Of Expression ◽  
Lower Growth ◽  
Content Type ◽  
Rate Dependent

ABSTRACTEnterococcus faecalisV583 was grown in a glucose-limited chemostat at three different growth rates (0.05, 0.15, and 0.4 h−1). The fermentation pattern changed with growth rate, from a mostly homolactic profile at a high growth rate to a fermentation dominated by formate, acetate, and ethanol production at a low growth rate. A number of amino acids were consumed at the lower growth rates but not by fast-growing cells. The change in metabolic profile was caused mainly by decreased flux through lactate dehydrogenase. The transcription ofldh-1, encoding the principal lactate dehydrogenase, showed very strong growth rate dependence and differed by three orders of magnitude between the highest and the lowest growth rates. Despite the increase inldh-1 transcript, the content of the Ldh-1 protein was the same under all conditions. Using microarrays and quantitative PCR, the levels of 227 gene transcripts were found to be affected by the growth rate, and 56 differentially expressed proteins were found by proteomic analyses. Few genes or proteins showed a growth rate-dependent increase or decrease in expression across the whole range of conditions, and many showed a maximum or minimum at the middle growth rate (i.e., 0.15 h−1). For many gene products, a discrepancy between transcriptomic and proteomic data were seen, indicating posttranscriptional regulation of expression.

Very High Growth Rate of 4H-SiC Using MTS as Chloride-Based Precursor

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Linear Dependence ◽  
Growth Rates ◽  
Molar Fraction ◽  
High Growth ◽  
High Growth Rate ◽  
Epitaxial Layers ◽  
Single Precursor ◽  
Very High

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.

Biomass Reduction and Mineralization Increase Due to the Ciliate Tetrahymena pyriformis Grazing on the Bacterium Pseudomonas fluorescens

1994 ◽  
Vol 29 (7) ◽  
pp. 119-128 ◽  
Author(s):  
C. H. Ratsak ◽  
B. W. Kooi ◽  
H. W. van Verseveld
Keyword(s):  
Growth Rates ◽  
Growth Parameters ◽  
Waste Water Treatment ◽  
High Growth ◽  
Tetrahymena Pyriformis ◽  
Lower Growth ◽  
Purification Efficiency ◽  
High Purification ◽  
Biomass Reduction ◽  
Sludge Production

The currently high sludge production and increasing processing costs call for waste-water treatment plants with high purification efficiency and low biomass production. We studied the latter issue through two-stage chemostat cascades to assess the overall biomass reduction due to ciliate grazing. The bacteria were cultured in the first chemostat whereas the ciliates, grazing on the bacteria from the first chemostat, were cultured in the second chemostat. Mathematical modelling was used to describe the bacteria/ciliate dynamics and some of the growth parameters were fitted. In the second chemostat 22-44% of the carbon originating from the first chemostat was mineralized to CO2. An extra biomass reduction of 12-43% was possible due to grazing by the ciliates. At lower growth rates of the ciliates the extra biomass reduction was higher than at high growth rates. This finding is auspicious, suggesting that predator organisms indeed can reduce sludge production.

scholarly journals Rapid Growth of UropathogenicEscherichia coliduring Human Urinary Tract Infection

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Valerie S. Forsyth ◽  
Chelsie E. Armbruster ◽  
Sara N. Smith ◽  
Ali Pirani ◽  
A. Cody Springman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Urinary Tract ◽  
Growth Rates ◽  
High Growth ◽  
Replication Forks ◽  
Chromosomal Replication ◽  
E Coli ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenicE. coli(ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than otherE. coliisolates and survive in that niche. To date, there has not been a reliable method available to measure their growth ratein vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robustin vivo, matching or exceedingin vitrogrowth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth ratesin vivoat 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR,E. coliin urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth ratesin vivoand resistance to the innate immune response appear to be critical phenotypes of UPEC strains.IMPORTANCEUropathogenicEscherichia coli(UPEC) strains cause most urinary tract infections in otherwise healthy women. While we understand numerous virulence factors are utilized byE. colito colonize and persist within the urinary tract, these properties are inconsequential unless bacteria can divide rapidly and survive the host immune response. To determine the contribution of growth rate to successful colonization and persistence, we employed two methods: one involving the segregation of a nonreplicating plasmid in bacteria as they divide and the peak-to-trough ratio, a sequencing-based method that enumerates chromosomal replication forks present during cell division. We found that UPEC strains divide extraordinarily rapidly during human UTIs. These techniques will be broadly applicable to measurein vivogrowth rates of other bacterial pathogens during host colonization.

Trichostrongylosis and wool growth. 2. The wool growth response of infected sheep to parenteral and duodenal cystine and cysteine supplementation

1973 ◽  
Vol 13 (63) ◽  
pp. 351 ◽  
Author(s):  
IA Barger ◽  
WH Southcott ◽  
VJ Williams
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Response ◽  
Infected Sheep ◽  
Trichostrongylus Colubriformis ◽  
Intestinal Nematode ◽  
Wool Growth ◽  
Cysteine Hydrochloride ◽  
Significant Difference ◽  
Maintenance Ration

Two experiments are reported. In experiment 1, light infections with the intestinal nematode Trichostrongylus colubriformis reduced wool growth of sheep by 42 per cent compared with pair-fed controls. There was no significant difference in wool growth between those sheep given a cystine supplement as an intraperitoneal pellet and those given a daily intra-duodenal injection of cystine, although cystine was poorly absorbed from the peritoneal cavity. In experiment 2, fifteen sheep were fed a maintenance ration and their wool growth rates defined. When six of the sheep were given a daily intra-duodenal drip containing 2 g cysteine hydrochloride, and six sheep were given the same drip intravenously, their wool growth rate increased by a mean of 33 per cent compared with the wool growth of the three untreated sheep, irrespective of the route of administration of the cysteine. Three sheep in each group of six were then lightly infected with Trichostrongylus colubriformis and the wool production of all sheep was measured in the presence and absence of the daily cysteine supplement via the two routes. The infection depressed wool growth, but did not influence the wool growth response to either route of cysteine supplementation. It was concluded that the reduced wool growth induced by trichostrongylosis could not be attributed to malabsorption of cysteine. Evidence was obtained that sheep resistant to Trichostrongylus colubriformis produced less wool when subjected to a larval challenge.

An analysis of growth of different cattle genotypes reared in different environments

1984 ◽  
Vol 103 (1) ◽  
pp. 137-153 ◽  
Author(s):  
J. E. Frisch ◽  
T. E. Vercoe
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Environmental Stresses ◽  
Growth Potential ◽  
Gastrointestinal Helminths ◽  
Treatment Groups ◽  
Survival And Growth ◽  
Different Levels ◽  
High Growth Potential

SummaryCalves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.

Heterogeneous growth rates of pancreatic adenocarcinoma by retrospective analysis of CT imaging data.

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 248-248
Author(s):  
Tanner Mortenson ◽  
Allison Bigeh ◽  
Yighua Chen ◽  
Michael Malek-Ahmadi ◽  
Kewei Chen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Screening Method ◽  
The United States ◽  
Ct Imaging ◽  
Rate Of Change ◽  
Ductal Adenocarcinoma ◽  
Cancer Center ◽  
Area Change ◽  
Significant Difference

248 Background: Pancreatic ductal adenocarcinoma (PDAC) remains the fourth leading cause of cancer death in the United States. Despite its high mortality, there is no effective screening method or frequency. The purpose of this study is to retrospectively evaluate prediagnostic CT images in order to identify growth rate and determine a potential surveillance frequency for at risk patients. Methods: 188 PDAC patients were seen at Banner MD Anderson Cancer Center (BMDACC) from 1/1/2012 to 12/31/2015. 24 patients met the final inclusion and exclusion criteria. Tumor area on CT imaging was then evaluated for rate of change prior to diagnosis. Both absolute and relative areas were plotted against time prior to diagnosis at 3, 6, 9, 12, 24, 36, 48, 60, and 72 months. Results: With two exceptions, no evidence of malignancy was identifiable at two or more years prior to diagnosis. Growth rates per year varied significantly. Absolute area change ranged from 1.7 cm2/yr to 139.22 cm2/yr; relative area change ranged from 1.17 to 7.15. Assuming a spherical mass, these relative changes correspond to relative volume change (ratio) per year of 1.27 and 19.13; the equivalent linear tumor doubling times are 3.7 years and 20 days respectively. Student’s T-test yielded no significant difference for relative growth, absolute growth, PFS, or OS between male and female patients. Conclusions: The heterogeneity in growth rate has significant implications for potential screening of PDAC. Screening interval greater than 1 year is feasible with other slow growing tumors. However, annual screening is not feasible for rapidly growing PDAC. Based on our findings, screening may need to be as frequent as 3-month intervals which would incur significant economic cost. Further correlation of prediagnostic growth rate with molecular changes may be necessary to discover the driver of this heterogeneous growth pattern.

Relationship between bone growth rate and bone tissue organization in amniotes: first test of Amprino's rule in a phylogenetic context

2010 ◽  
Vol 60 (1) ◽  
pp. 25-41 ◽  
Author(s):  
Jacques Castanet ◽  
Jorge Cubo ◽  
Laëtitia Montes
Keyword(s):  
Growth Rate ◽  
Bone Tissue ◽  
Growth Rates ◽  
Bone Growth ◽  
Phylogenetic Signal ◽  
Variation Partitioning ◽  
High Growth ◽  
Tissue Organization ◽  
Shared Ancestry ◽  
Functional Factors

AbstractA debate on the determinism (phylogenetic versus functional) of the diversity of bone histological features has centred the interest of bone comparative biologists. While some authors have noticed the presence of a phylogenetic signal in bone tissue variation, many others have argued that these characters may not include much phylogenetic information, but rather reflect functional factors. Here we quantify both components in a sample of amniotes. We hypothesize that: 1/ the observed variation is partly the outcome of shared ancestry (phylogenetic factor) and 2/ for a given quantity of bone produced, tissues formed at a rapid rate may have a higher fraction of vascular cavities than those produced at a slower rate (functional factor). Variation partitioning analyses show that the phylogeny explains a significant portion of the variation of bone vascularity (85.3%), bone growth rate also explains a significant portion of this variation (68.3%), and there is an important overlap (67.9%). Finally, an optimization through least-squares parsimony of bone growth rates onto the phylogeny shows that the most important evolutionary change may have occurred after the split between crocodiles and birds. This change may be linked to the origin of avian endothermic metabolism because high growth rates involve high protein turnover, which is very energy consuming. We conclude that the debate on the dichotomy between phylogenetic versus functional causation of bone histological diversity is misleading, because we have shown that bone vascularity has, at the same time, a functional significance and a phylogenetic signal.

scholarly journals Campylobacter Colonization and Proliferation in the Broiler Chicken upon Natural Field Challenge Is Not Affected by the Bird Growth Rate or Breed

2014 ◽  
Vol 80 (21) ◽  
pp. 6733-6738 ◽  
Author(s):  
Fraser J. Gormley ◽  
Richard A. Bailey ◽  
Kellie A. Watson ◽  
Jim McAdam ◽  
Santiago Avendaño ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Consumer Preferences ◽  
Pure Line ◽  
Public Health Perspective ◽  
Content Type ◽  
Commercial Flock ◽  
Significant Difference ◽  
Commercial Broiler ◽  
Market Needs

ABSTRACTThe zoonotic association betweenCampylobacterbacteria in poultry and humans has been characterized by decades of research which has attempted to elucidate the epidemiology of this complex relationship and to reduce carriage within poultry. While much work has focused on the mechanisms facilitating its success in contaminating chicken flocks (and other animal hosts), it remains difficult to consistently excludeCampylobacterunder field conditions. Within the United Kingdom poultry industry, various bird genotypes with widely varying growth rates are available to meet market needs and consumer preferences. However, little is known about whether any differences inCampylobactercarriage exist across this modern broiler range. The aim of this study was to establish if a relationship exists between growth rate or breed and cecalCampylobacterconcentration after natural commercial flockCampylobacterchallenge. In one investigation, four pure line genotypes of various growth rates were grown together, while in the second, eight different commercial broiler genotypes were grown individually. In both studies, theCampylobacterconcentration was measured in the ceca at 42 days of age, revealing no significant difference in cecal load between birds of different genotypes both in mixed- and single-genotype pens. This is important from a public health perspective and suggests that other underlying reasons beyond genotype are likely to control and affectCampylobactercolonization within chickens. Further studies to gain a better understanding of colonization dynamics and subsequent proliferation are needed, as are novel approaches to reduce the burden in poultry.

scholarly journals Synthesis and Fermentation Properties of Novel Galacto-Oligosaccharides by β-Galactosidases fromBifidobacterium Species

2001 ◽  
Vol 67 (6) ◽  
pp. 2526-2530 ◽  
Author(s):  
Bodun A. Rabiu ◽  
Andrew J. Jay ◽  
Glenn R. Gibson ◽  
Robert A. Rastall
Keyword(s):  
Growth Rate ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Growth Rates ◽  
Transfer Reactions ◽  
Methylation Analysis ◽  
Lower Growth ◽  
Lactose Concentration ◽  
Pure Cultures ◽  
Layer Chromatography

ABSTRACT β-Galactosidase enzymes were extracted from pure cultures ofBifidobacterium angulatum, B. bifidum BB-12, B. adolescentis ANB-7, B. infantis DSM-20088, andB. pseudolongum DSM-20099 and used in glycosyl transfer reactions to synthesize oligosaccharides from lactose. At a lactose concentration of 30% (wt/wt) oligosaccharide yields of 24.7 to 47.6% occurred within 7 h. Examination of the products by thin-layer chromatography and methylation analysis revealed distinct product derived spectra from each enzyme. These were found to be different to that of Oligomate 55, a commercial prebiotic galacto-oligosaccharide. Fermentation testing of the oligosaccharides showed an increase in growth rate, compared to Oligomate 55, with products derived fromB. angulatum, B. bifidum, B. infantis, and B. pseudolongum. However B. adolescentis had a lower growth rates on its oligosaccharide compared with Oligomate 55. Mixed culture testing of the B. bifidum BS-4 oligosaccharide showed that the overall prebiotic effect was equivalent to that of Oligomate 55.

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