Effect of protozoan predation on relative abundance of fast- and slow-growing bacteria

1989 ◽  
Vol 35 (5) ◽  
pp. 578-582 ◽  
Author(s):  
James L. Sinclair ◽  
Martin Alexander
Keyword(s):  
Growth Rate ◽  
Bacterial Community ◽  
Relative Abundance ◽  
Growth Rates ◽  
Bacterial Species ◽  
Test Species ◽  
Fast Growing ◽  
Population Sizes ◽  
Slow Growing ◽  
Fast Growing Species

The survival of six bacterial species that had different growth rates was tested in raw sewage and sewage that was rendered free of protozoa. When test bacteria were added to protozoa-free sewage at densities of approximately 105 to 106 cells/mL, five of the six species did not decline below 105 cells/mL. If protozoa were present, the population sizes of all test species were markedly reduced, but bacterial species able to grow faster in artificial media had the larger number of survivors. When the same bacteria were inoculated into protozoa-free sewage at densities of less than 103 cells/mL, only the three species able to grow quickly in artificial media increased in abundance. When the six species were inoculated at the same densities into sewage containing protozoa, the three slow-growing species were rapidly eliminated, and two of the three fast-growing species survived in detectable numbers. We suggest that in environments with intense protozoan predation, protozoa may alter the composition of the bacterial community by eliminating slow-growing bacteria.Key words: growth rate, predation, protozoa, sewage.

scholarly journals Effects of Initial Soil Properties on Three-Year Performance of Six Tree Species in Tropical Dry Forest Restoration Plantings

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 428 ◽  
Author(s):  
Valentina Carrasco-Carballido ◽  
Cristina Martínez-Garza ◽  
Héctor Jiménez-Hernández ◽  
Flavio Márquez-Torres ◽  
Julio Campo
Keyword(s):  
Soil Properties ◽  
Growth Rates ◽  
Tropical Dry Forest ◽  
Dry Forest ◽  
Diameter Growth ◽  
Relative Growth ◽  
Fast Growing ◽  
Initial Soil ◽  
Slow Growing ◽  
Fast Growing Species

Deforestation of tropical dry forest reduces soil fertility, with negative effects on future restoration intervention. To evaluate the effect of initial soil properties on three-year performance of six tree species in restoration settings, we measured C, N, and P contents in topsoils of 48 plots under minimal (exclusions of livestock grazing) and maximal (plantings of six native species) restoration intervention during two years in tropical dry forest in central Mexico. Survival and height and diameter relative growth rates were evaluated by species and by growth rank (three fast- and three slow-growing species). After two years, organic C and the C:N ratio increased early during natural succession; these increases might be related to high density of N2-fixing recruits at both intervention levels. Changes in N availability for plants (i.e., NO3− and NH4+ contents) occurred after cattle exclusion. After 40 months, the fast-growing legume Leucaena esculenta (DC.) Benth. had the highest survival (65.55%) and relative growth rate in both height (3.16%) and diameter (5.67%). Fast-growing species had higher survival and diameter growth rates than slow-growing species. Higher diameter growth rates for fast-growing species may be associated with a higher ability to forage for soil resources, whereas similar height growth rates for slow and fast-growing species suggested low competition for light due to slow natural succession at the site. Planted seedlings had higher survival possibly due to initial high NO3− content in the soil. Also, fast-growing species seem to benefit from initially higher pH in the soil. Both soil properties (i.e., pH and NO3−) may be augmented to favor the performance of fast-growing species in restoration plantings and to further accelerate soil recovery in tropical dry forests.

scholarly journals Breast meat quality of chickens with divergent growth rates and its relation to growth curve parameters

2017 ◽  
Vol 60 (4) ◽  
pp. 427-437 ◽  
Author(s):  
Philipp C. Muth ◽  
Anne Valle Zárate
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Meat Quality ◽  
Growth Curve ◽  
Growth Rates ◽  
Cooking Loss ◽  
Growth Potential ◽  
Breast Meat ◽  
Fast Growing ◽  
Slow Growing

Abstract. The effects of the increase of body weight of contemporary broilers during growth on functional meat quality and color characteristics of the chicken breast muscle are controversially debated. Therefore, male chickens (n = 264) of a fast-growing commercial broiler (Ross 308) and two slow-growing experimental meat-type chicken lines were compared at equal age and at similar body weight in order to investigate the effect of growth rate on selected functional breast meat traits and meat color. Additionally, the breast meat characteristics of birds with different growth profiles were compared within lines. When the body weight of commercial broilers reached about 40 to 60 % of their growth potential, they exhibited particularly high ultimate pH values compared with slow-growing lines. The ability of the meat of fast-growing broilers to retain water during cooking was impaired (5 to 16 percentage points increased cooking loss compared to slow-growing lines), which, in contrast to pH, was only marginally affected by body weight and/or age at slaughter. No unfavorable correlations of breast meat quality traits with the growth profile, represented by growth curve parameters derived from the Gompertz–Laird equation, were detected within any of the investigated chicken lines. It is noteworthy that the associations of ultimate pH and cooking loss with maximum growth speed indicate a non-linear relationship. Thus, some of the functional characteristics of breast meat of the fast-growing broiler resembled the white-striping defect described for poultry meat, but the hypothesis that selection on increased growth rates is detrimental for meat quality per se could not be confirmed. In fact, an elevated growth potential in particular, i.e., body weight at maturity, could have some beneficial effects for the water-holding capacity of breast meat, regardless of the genotypic growth rate.

scholarly journals 221 Effect of varying growth rates on early and aged pork loin and chop quality

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 46-47
Author(s):  
Emily D Schunke ◽  
Jessica E Lowell ◽  
Chad A Stahl ◽  
Bailey N Harsh ◽  
Anna C Dilger
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Average Daily Gain ◽  
Growing Pigs ◽  
Pork Industry ◽  
Fast Growing ◽  
Visual Color ◽  
Main Effects ◽  
Slow Growing ◽  
Daily Gain

Abstract The pork industry has observed an upward trend in ending live weights, resulting in heavier hot carcass weights (HCW). Heavier HCW positively affects loin tenderness; however, the mechanism of this effect is unclear. One possibility is increased growth rate, associated with greater HCW, resulting in more tender loins. The objective was to determine the effect of growth rate on early and aged pork quality. Pigs (N=634) were divided into three groups based on average daily gain (kg/d) from 12-26wk of age; slow (< 0.96kg/d, n=96), intermediate (0.96-1.16kg/d, n=452), and fast (≥ 1.17kg/d, n=86). The MIXED procedure of SAS was used to evaluate the main effects of growth rate, breed, sex, and their interactions on loin quality. Birth and weaning weight did not differ between growth rate (P≥0.15) but, overall ADG was increased (P<0.001) in fast growing pigs by 0.15 kg/d. Fast and intermediate growing pigs had darker loins (P=0.03) by 0.23 units. Intermediate growing pigs had firmer loins (P=0.04) by 0.07 units. Ventral a* increased as growth rate increased (P=0.04) indicating fast growing pigs had the reddest loins (9.77 vs. 9.26 vs. 8.99). Aged ventral marbling, ultimate pH, purge loss, cook loss, instrumental tenderness, and chop moisture and extractable lipid did not differ (P≥0.32) between growth rate groups. Duroc-sired pigs had increased tenth rib back fat amongst all growth rate groups, but the magnitude of difference was much greater in the slow and intermediate groups. Between all growth rate groups, slow growing Pietrain-sired Pigs had the smallest loineye areas (LEA). Carcass yield, bone-in carcass cutting yield, and boneless carcass cutting yield did not differ (P≥0.37) between growth rate groups. While fast growth rates improved aged ventral visual color, instrumental tenderness did not differ between growth rate groups.

scholarly journals Current state of Donetsk dendroflora

2016 ◽  
Vol 5 (2) ◽  
pp. 20-24
Author(s):  
Alexandr Zakharovych Glukhov ◽  
Lyudmila Valerievna Kharkhota ◽  
Georgy Alexandrovych Pasternak ◽  
Elena Nikolaevna Likhatskaya
Keyword(s):  
Age Structure ◽  
Steppe Zone ◽  
Age Group ◽  
Fast Growing ◽  
Industrial City ◽  
Current State ◽  
Study Results ◽  
Slow Growing ◽  
Trees And Shrubs ◽  
Fast Growing Species

We present the study results of modern dendroflora of Donetsk (a large industrial city of the south steppe zone). We have determined the species composition, analyzed the age structure of plantations, estimated the life condition of trees and shrubs. Plantations compose 76 species and 32 forms, types, sorts of trees, including 11 species and 9 sorts of the coniferous, as well as 79 species and 35 forms, sorts of shrubs, including 7 species and 19 sorts of the coniferous. Trees and shrubs belong to 78 genera, which are included into 38 families. The most represented family among the deciduous is Rosaceae Juss. - 46 species and 13 sorts, among the coniferous - Pinaceae Lindl. (9 species and 6 sorts), Cupressaceae Rich. ex Bartl. (7 species and 22 sorts). Tree species dominating in plantations are Populus bolleana Lauche (14,6% of the total number of trees), dominating shrubs are the sorts of Rosa hybrida (44,0% of the total number of shrubs). In the plantations studied we have indicated 33 species of trees and shrubs of the aboriginal fraction of local flora. Analysis of the age structure of plantations revealed that the majority of trees compose the age group of 20-29 years, the majority of shrubs - up to 10 years. Fast-growing species prevail in plantations (73% of the total number). Viability of the most part of trees of fast-growing and slow-growing species is estimated by 4 points, viability of moderate-growing species - by 6 points. The number of trees being in unsatisfactory condition (0 or 1-3 points) prevails among fast-growing species.

The Translocation of 14C-photoassimilate in Single Tree Progeny of White Spruce (Piceaglauca (Moench) Voss)

1973 ◽  
Vol 3 (2) ◽  
pp. 315-318 ◽  
Author(s):  
D. J. Ursino
Keyword(s):  
Growth Rate ◽  
White Spruce ◽  
Shoot Height ◽  
Fast Growing ◽  
Single Tree ◽  
Slow Growing

Young trees from seedlots representing single tree progeny of white spruce and assessed as either fast- or slow-growing on the basis of shoot height, were allowed to photoassimilate 14CO2 and either 24 or 48 h later, the magnitude and distribution of 14C were determined. In comparison to the slow-growing plants 48 h after 14CO2 photoassimilation, the fast-growing spruce retained a higher percentage of the assimilated 14C and translocated less to the root. Differences in growth rate between the seedlots did not affect the partitioning of 14C between the 80% ethanol-soluble and -insoluble fractions.

Effect of a pesticide pentachlorophenol on soil microflora. III. Growth rates as an index of pesticide resistance of bacterial groups isolated from soil

1987 ◽  
Vol 33 (9) ◽  
pp. 819-822 ◽  
Author(s):  
Kyo Sato
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Growth Rates ◽  
Bacterial Species ◽  
Bacterial Flora ◽  
Soil Microflora ◽  
Pesticide Resistance ◽  
Relative Growth ◽  
Bacterial Groups

Pentachlorophenol resistance was investigated in bacteria isolated from glycine- or water-percolated soils where the bacterial flora was modified by the addition of pentachloropenol. The strains isolated from the water-percolated soil amended with PCP had the highest resistance, and the addition of glycine to the percolated soil weakened the resistance. The strains from the glycine-percolated soil without pentachlorophenol had a medium degree of resistance, and the resistance of the strains from the water-percolated soil without PCP was the lowest. The bacterial groups were sorted taxonomically; differences in pentachloropenol resistance were correlated with taxonomic groupings. Relative growth rate in the presence of pentachlorophenol was proposed as a useful means to distinguish among the bacterial species.

scholarly journals Analysis of the fecal microbiota of fast- and slow-growing rainbow trout (Oncorhynchus mykiss)

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Pratima Chapagain ◽  
Brock Arivett ◽  
Beth M. Cleveland ◽  
Donald M. Walker ◽  
Mohamed Salem
Keyword(s):  
Growth Rate ◽  
Gut Microbiota ◽  
Dna Extraction ◽  
Significant Variation ◽  
Extraction Methods ◽  
Fish Growth ◽  
Indicator Taxa ◽  
Fast Growing ◽  
Dna Extraction Methods ◽  
Slow Growing

Abstract Background Diverse microbial communities colonizing the intestine of fish contribute to their growth, digestion, nutrition, and immune function. We hypothesized that fecal samples representing the gut microbiota of rainbow trout could be associated with differential growth rates observed in fish breeding programs. If true, harnessing the functionality of this microbiota can improve the profitability of aquaculture. The first objective of this study was to test this hypothesis if gut microbiota is associated with fish growth rate (body weight). Four full-sibling families were stocked in the same tank and fed an identical diet. Two fast-growing and two slow-growing fish were selected from each family for 16S rRNA microbiota profiling. Microbiota diversity varies with different DNA extraction methods. The second objective of this study was to compare the effects of five commonly used DNA extraction methods on the microbiota profiling and to determine the most appropriate extraction method for this study. These methods were Promega-Maxwell, Phenol-chloroform, MO-BIO, Qiagen-Blood/Tissue, and Qiagen-Stool. Methods were compared according to DNA integrity, cost, feasibility and inter-sample variation based on non-metric multidimensional scaling ordination (nMDS) clusters. Results Differences in DNA extraction methods resulted in significant variation in the identification of bacteria that compose the gut microbiota. Promega-Maxwell had the lowest inter-sample variation and was therefore used for the subsequent analyses. Beta diversity of the bacterial communities showed significant variation between breeding families but not between the fast- and slow-growing fish. However, an indicator analysis determined that cellulose, amylose degrading and amino acid fermenting bacteria (Clostridium, Leptotrichia, and Peptostreptococcus) are indicator taxa of the fast-growing fish. In contrary, pathogenic bacteria (Corynebacterium and Paeniclostridium) were identified as indicator taxa for the slow-growing fish. Conclusion DNA extraction methodology should be carefully considered for accurate profiling of the gut microbiota. Although the microbiota was not significantly different between the fast- and slow-growing fish groups, some bacterial taxa with functional implications were indicative of fish growth rate. Further studies are warranted to explore how bacteria are transmitted and potential usage of the indicator bacteria of fast-growing fish for development of probiotics that may improve fish health and growth.

Aphid fitness on 13 grass species: a test of plant defence theory

2000 ◽  
Vol 77 (12) ◽  
pp. 1783-1789 ◽  
Author(s):  
Lauchlan H Fraser ◽  
J Philip Grime
Keyword(s):  
Growth Rate ◽  
Aboveground Biomass ◽  
Plant Defence ◽  
Grass Species ◽  
Fast Growing ◽  
Grain Aphid ◽  
Growth Rate Hypothesis ◽  
Aphid Feeding ◽  
Grass Growth ◽  
Slow Growing

The growth rate hypothesis, which states that fast-growing plants support more herbivores than slow-growing plants, was tested with 12 native and 1 naturalized British grasses using the grain aphid (Sitobion avenae). Five aphids were enclosed with grasses for two weeks in a growth chamber. After 2 weeks, fast-growing plants had 38 aphids, whilst slow-growing plants had 6, which supports the growth-rate hypothesis. When aphid numbers were analysed on plants according to "CSR" theory (Grime 1977, 1979), ruderals (R) had 54, competitors (C) had 18, and stress tolerators (S) had 6. This supports the predictions of CSR theory. Furthermore, aphid numbers increased significantly with grass growth rates and a mollusc palatability index, although this largely resulted from a single outlier, Poa annua. Aphid number was not affected by hairs on grasses. Finally, the effect of aphid feeding on grasses was tested. Generally, the greatest change in total and aboveground biomass of the grasses was found in the ruderals, whilst stress tolerators had the least amount of change.

scholarly journals Sinorhizobium meliloti, a Slow-Growing Bacterium, Exhibits Growth Rate Dependence of Cell Size under Nutrient Limitation

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Xiongfeng Dai ◽  
Zichu Shen ◽  
Yiheng Wang ◽  
Manlu Zhu
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Cell Size ◽  
Sinorhizobium Meliloti ◽  
Cell Cycle Progression ◽  
Bacterial Species ◽  
Progression Rate ◽  
Content Type ◽  
E Coli ◽  
Slow Growing

ABSTRACTBacterial cells need to coordinate the cell cycle with biomass growth to maintain cell size homeostasis. For fast-growing bacterial species likeEscherichia coliandBacillus subtilis, it is well-known that cell size exhibits a strong dependence on the growth rate under different nutrient conditions (known as the nutrient growth law). However, cell size changes little with slow growth (doubling time of >90 min) forE. coli, posing the interesting question of whether slow-growing bacteria species also observe the nutrient growth law. Here, we quantitatively characterize the cell size and cell cycle parameter of a slow-growing bacterium,Sinorhizobium meliloti, at different nutrient conditions. We find thatS. melilotiexhibits a threefold change in its cell size when its doubling time varies from 2 h to 6 h. Moreover, the progression rate of its cell cycle is much longer than that ofE. coli, suggesting a delicate coordination between the cell cycle progression rate and the biomass growth rate. Our study shows that the nutrient growth law holds robustly regardless of the growth capacity of the bacterial species, generalizing its applicability among the bacterial kingdom.IMPORTANCEThe dependence of cell size on growth rate is a fundamental principle in the field of bacterial cell size regulation. Previous studies of cell size regulation mainly focus on fast-growing bacterial species such asEscherichia coliandBacillussubtilis. We find here thatSinorhizobium meliloti, a slow-growing bacterium, exhibits a remarkable growth rate-dependent cell size pattern under nutrient limitation, generalizing the applicability of the empirical nutrient growth law of cell size. Moreover,S. melilotiexhibits a much slower speed of cell cycle progression thanE. colidoes, suggesting a delicate coordination between the cell cycle progression rate and the biomass growth rate.

Gas exchange and water relations responses to drought of fast- and slow-growing black spruce families

1997 ◽  
Vol 75 (10) ◽  
pp. 1700-1706 ◽  
Author(s):  
Weixing Tan ◽  
Terence J. Blake
Keyword(s):  
Growth Rate ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Soil Water ◽  
Water Relations ◽  
Picea Mariana ◽  
Black Spruce ◽  
Turgor Pressure ◽  
Fast Growing ◽  
Slow Growing

To determine how different mechanisms of drought tolerance contribute to growth rate under drought, this study compared four full-sib black spruce (Picea mariana (Mill.) B.S.P.) families which differed in growth rate when soil water became limiting, stomatal conductance, photosynthesis, and water relations responses to drought. Repeated drought cycles were imposed by withholding soil water in a nursery and physiological responses were measured near the end of the first and third cycle. The most vigorous family under drought had greater osmotic adjustment and maintained higher rates of net photosynthesis during the first cycle of drought and resumed higher rates of photosynthesis sooner upon stress relief, compared with two slow-growing families. Pressure–volume analysis of drought-stressed shoot tissues indicated that the fast-growing family exhibited a larger degree of elastic enhancement (i.e., decrease in bulk modulus of elasticity), which would explain its higher turgor pressure, compared with the two less vigorous families. However, family differences in gas exchange and water relations largely diminished when seedlings were exposed to repeated cycles of drought. Therefore, fast-growing black spruce families under drought may gain selective growth advantage by a better ability to tolerate, rather than postpone, momentary dehydration. Short-term screening trials could be used to detect drought tolerant genotypes in black spruce. Key words: drought, family variation, photosynthesis, Picea mariana, stomatal conductance, water relations.

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