Effect of fibroblast growth factors 1, 2, 4, 5, 6, 7, 8, 9, and 10 on avian chondrocyte proliferation.

It has been demonstrated that fibroblast growth factor receptors are key regulators of endochondral bone growth. However, it has not been determined what fibroblast growth factor ligand(s) (FGFs) are important in this process. This study sought to determine whether FGFs 1, 2, 4, 5, 6, 7, 8, 9, and 10 were capable of stimulating avian chondrocyte proliferation in vitro. We have found that FGFs 2, 4, and 9 strongly stimulate avian chondrocyte proliferation while FGFs 6 and 8 stimulate proliferation to a lesser extent. RT-PCR indicates that FGF-2 and FGF-4 are expressed in the postnatal avian epiphyseal growth plate (EGP) while FGF-8 and FGF-9 are not. Thus, FGF-2 and FGF-4 stimulate chondrocyte proliferation and are both present in the EGP. This suggests that FGF-2 and FGF-4 may be important ligands, in vivo, for the regulation of endochondral bone growth. These observations coupled with our observation that multiple avian FGF receptors (Cek1, Cek2, Cek3, and FREK) are expressed in proliferative chondrocytes highlights the complexity of FGF signaling pathways in postnatal endochondral bone growth.     

Effects of culture media, temperature, pH, and light on growth, sporulation, germination, and bioherbicidal efficacy of Phoma exigua, a potential biological control agent for salal (Gaultheria shallon)

In order to evaluate the potential use of Phoma exigua isolate PFC 2705 (PFC2705) as a biological control agent for salal (Gaultheria shallon), effect of cultural and environmental parameters on growth, conidia production, and pathogenicity of P. exigua were characterized in studies conducted under laboratory and greenhouse conditions. Within a range of 5-30°C, the optimum growth and germination temperature range was 20-25°C. The effect of pH on mycelial growth and conidial germination was not significant from pH 5 to 10. Fluorescent light significantly enhanced sporulation of the fungus on most agar media tested, yet was not necessary for growth. The type of culture media significantly affected mycelium growth, sporulation, and conidia germination. Age of mycelia used as inoculum affected the disease severity on salal. PFC2705 suppressed the growth of mature salal plant by inciting lesions on leaves, branch tips, and axillary buds and caused 56% death of the total biomass above ground. Characteristics such as easy inoculum production, wide range of growth environments, and high infectivity on salal increased the potential of P. exigua as a biocontrol agent for management of salal.     

Growth and hare, Lepus timidus, resistance of white birch, Betula pendula, clones grown in different soil types

Many plant species have the ability to expand laterally through space by clonal growth. Plant pathogens can affect clonal growth characteristics thereby altering the success of host plants within populations and of clonal species within communities. We conducted a greenhouse experiment to determine the effects of the systemic fungal pathogen, Epichloë glyceriae , on clonal growth patterns of its host grass, Glyceria striata . We found that infected and uninfected plants produced similar total biomass and numbers of tillers plus primary stolons per mother ramet. However, biomass allocation to tillering (vegetative growth) vs stolon production (clonal growth) was significantly affected by pathogen infection. Infected plants produced more stolons and clonal growth biomass than uninfected plants while mother ramets of uninfected plants produced more tillers and biomass than infected plants. Stolon architecture of infected and uninfected plants also differed. In two of three populations, infected plants produced stolons with greater biomass and shorter spacer lengths, even though mean stolon lengths were similar for infected and uninfected plants. These results contrast strongly with most other clonal plant-pathogen systems where infected plants are less vigorous and have reduced clonal growth compared to uninfected plants. Greater clonal growth may be an effective mechanism for host genotypes to persist and spread when seed production is prevented, as is the case with castrating pathogens like Epichloë glyceriae .     

Parasitism, developmental plasticity and bilateral asymmetry of wing feathers in alpine swift, Apus melba, nestlings

The hypothesis that developmental instability is a cost of developmental plasticity is explored using the alpine swift ( Apus melba ) as a model organism. In a previous study, experimentally parasitized nestlings showed a reduced wing growth rate in the first half of the rearing period when parasites were abundant (i.e. peak infestation) and an accelerated growth rate (i.e. compensatory growth) in the second half when parasites decreased in number. This suggests that alpine swifts are able to adjust growth rate in relation to variation in parasite loads. Because developmental plasticity may entail fitness costs, the energy required to sustain compensatory growth may be invested at the expense of developmental stability, potentially resulting in larger deviations from symmetry in paired, bilateral traits (i.e. fluctuating asymmetry, FA). This hypothesis predicts higher FA in parasitized than deparasitized nestlings because of compensatory growth, and hence individuals sustaining the highest level of compensatory growth rate should exhibit the highest FA levels. Another non-mutually exclusive hypothesis argues that parasites directly cause FA by diverting energy required by host for maintenance and growth, and predicts that individuals suffering the most from parasitism during peak infestation should exhibit the highest FA levels. The present study shows that wing feathers of experimentally parasitized nestlings were more asymmetrical than those of experimentally deparasitized ones 50 days after hatching. Furthermore, in parasitized individuals FA was negatively correlated with wing growth rate during the period of peak infestation but not during the period of compensatory growth. These findings suggest that developmental homeostasis is more sensitive to parasites than to compensatory growth.     

Diarrhea,respiratory infections,protozoan gastrointestinal parasites,and child growth in Kathmandu,Nepal

The differential impact of diarrhea, respiratory infections, and protozoan parasitism on growth is investigated among children under five years of age living in periurban Kathmandu, Nepal. The children's parents are all carpet-making workers who live in an environment with crowded living conditions, poor sanitation, and contaminated water. Anthropometric data, both cross-sectional and longitudinal, were collected over a 9-month period. Morbidity data were gathered from maternal reports, and a subsample of children's stools were examined for gastrointestinal parasites. In a comparison of current growth status and growth velocity for children with and without diarrhea and respiratory infections, it is found that body weight is most affected by infections, particularly for children under 24 months of age. For a subsample of children whose stools were tested for parasites, there is a statistically significant association between stunting (low height-for-age) and the presence of a protozoan gastrointestinal parasite. It is concluded that although growth faltering is associated with diarrhea and respiratory infections, the impact of these infections is of less importance for long-term linear growth retardation than is infection by protozoan gastrointestinal parasites.     

ADAPTATION, CONSTRAINT, AND COMPROMISE IN AVIAN POSTNATAL DEVELOPMENT

1. This paper discusses factors that influence the evolution of growth rate and determine its variation among species of birds. Growth rate is related to evolutionary fitness through the use of time, energy, and nutrients. In addition, balances between factors favouring rapid growth and those favouring slow growth may be investigated directly by experiment and by comparative observation. 2. David Lack (1968) proposed that the growth rate of the young is the optimum balance between selection for rapid growth to reduce the vulnerable period of development and selection for slow growth to reduce the energy requirements of the young. 3. To test Lack's hypothesis, the growth rates of birds, estimated by fitting sigmoid equations to curves relating weight to age, were surveyed widely from the literature. Among all species examined, growth rate was inversely related to adult weight. Among birds of similar size, most variation in growth rate was related to the degree of maturity of the neonate. Altricial chicks, which depend upon their parents for food and warmth, grow more rapidly than precocial chicks, which are self-sufficient shortly after hatching. Lack's hypothesis, which predicts a direct relationship between growth rate and mortality rate, was not supported. 4. I propose that the key to understanding variation in growth rate among birds lies in the balance between rate of cell proliferation or cell growth, on one hand, and acquisition of mature function, on the other. This idea is consistent with principles of cellular and developmental biology. It is supported by comparisons of (a) the neonates of different species, (b) the individual over the course of the developmental period, and (c) tissues whose use is acquired at different stages of development, wherein more mature individuals or tissues grow more slowly than those with less developed function. 5. Species of birds that are classified as semi-precocial develop precocially but grow rapidly. Although these seemingly violate the general rule relating growth rate to precocity, a closer inspection of their development reveals that they too support the rule. In the Common Tern, the legs, which are the key organ in precocial development, grow at the expected slow rate. The body as a whole grows rapidly because the growth increment of the legs is small and their growth is completed quickly. 6. Growth rates of precocial birds do not decrease abruptly at hatching. This points more to gradual tissue differentiation than to the pattern of procurement and allocation of energy as the primary control for growth rate. 7. Precocious development is favoured when the chicks are capable of self-feeding or when food supplies are distant from the next site and travelling time between one and the other is long. Precocity of the neonates frees both parents to feed at a distant food source. 8. Some species having diets with low levels of protein or other nutrients may grow slowly in order to match nutrient requirements to their availability in the diet. This pattern is indicated especially among the Procellariiformes, which feed an oily diet to their young, and also among tropical fruit-eating birds. 9. Some tropical, pelagically-feeding sea-birds that rear only one offspring at a time may not be able to procure food sufficient to support rapid chick growth. Alternative explanations for slow growth among these species include difficulty in obtaining essential nutrients and more precocious development of activity than in related species having more rapid growth.     

Wolinella recta, Wolinella curva, Bacteroides ureolyticus, and Bacteroides gracilis are microaerophiles, not anaerobes.

Although the nonfermentative, asaccharolytic, putative anaerobes Wolinella curva, Wolinella recta, Bacteroides ureolyticus, and Bacteroides gracilis are phylogenetically related to the true campylobacters, the type strains of these species exhibited O2-dependent microaerophilic growth in brucella broth and on brucella agar. The optimum O2 levels for growth of these strains ranged from 4 to 14% in brucella broth and from 2 to 8% on brucella agar, when H2 was provided as the electron donor. No growth occurred under 21% O2, and scant or no growth occurred under anaerobic conditions unless fumarate or nitrate was provided as a terminal electron acceptor. Aspartate, asparagine, and malate also served as apparent electron acceptors. The organisms were catalase negative and, except for B. gracilis, oxidase positive. Catalase added to brucella broth enhanced growth. O2 uptake by all species was inhibited by cyanide and 2-heptyl-4-hydroxyquinoline N-oxide. We concluded that these organisms are not anaerobes but instead are microaerophiles, like their campylobacter relatives.     

Rubralactone, rubralides A, B and C, and rubramin produced by Penicillium rubrum

Rubralactone (1), rubralides A, B and C (2-4), rubramin (5), and 2-formyl-3,5-dihydroxy-4-methylbenzoic acid (6), were isolated from Penicillium rubrum, and their structures established by spectroscopic methods including 2D NMR. The effects on plant growth of 1-6 were examined using the lettuce seedling bioassay. Compound 1 promoted root growth. Compounds 2, 3 and 5 inhibited the growth of lettuce seedlings, but 4 and 6 did not have any inhibitory effect on their growth.     

Feeding, growth, and the thermal environment of cabbage white caterpillars, Pieris rapae L

Laboratory studies of temperature effects on short-term feeding and growth rates were combined with field data on thermal environments to explore the consequences of temperature variation for growth of caterpillars of the cabbage white butterfly, Pieris rapae. Mean short-term (24-h) consumption and growth rates of fourth-instar P. rapae feeding on collard leaves increased continuously with increasing temperatures between 10 degrees and 35 degrees C, peaked at 35 degrees C, and declined rapidly with temperatures above 35 degrees C. Physical models can mimic temperatures of real fifth-instar caterpillars under collard leaves within 1 degrees -2 degrees C in sunny summer conditions in Seattle, Washington. Continuous recordings of operative temperatures of model caterpillars in a collard garden suggest that, at the timescale of the duration of the fifth instar (5-8 d in the field), P. rapae caterpillars frequently experience temperatures spanning a 25 degrees C range, they spend most of their time at temperatures well below those that maximize growth, and they encounter substantial variation in the frequency distribution of operative temperatures between time periods. Combining these data on growth rate as a function of temperature and the distribution of operative temperatures in the field, I illustrate how growth rates at higher temperatures can make disproportionate contributions to the overall mean growth rates even when higher temperatures are relatively infrequent. Fluctuating thermal conditions may generate variable patterns of selection on reaction norms for growth rate in the field.     

Isolation, selection, and characterization of beneficial rhizobacteria from pea, lentil, and chickpea grown in western Canada

The use of beneficial soil microorganisms as agricultural inputs for improved crop production requires selection of rhizosphere-competent microorganisms with plant growth-promoting attributes. A collection of 563 bacteria originating from the roots of pea, lentil, and chickpea grown in Saskatchewan was screened for several plant growth-promoting traits, for suppression of legume fungal pathogens, and for plant growth promotion. Siderophore production was detected in 427 isolates (76%), amino-cyclopropane-1-carboxylic acid (ACC) deaminase activity in 29 isolates (5%), and indole production in 38 isolates (7%). Twenty-six isolates (5%) suppressed the growth of Pythium sp. strain p88-p3, 40 isolates (7%) suppressed the growth of Fusarium avenaceum, and 53 isolates (9%) suppressed the growth of Rhizoctonia solani CKP7. Seventeen isolates (3%) promoted canola root elongation in a growth pouch assay, and of these, 4 isolates promoted the growth of lentil and one isolate promoted the growth of pea. Fatty acid profile analysis and 16S rRNA sequencing of smaller subsets of the isolates that were positive for the plant growth-promotion traits tested showed that 39%-42% were members of the Pseudomonadaceae and 36%-42% of the Enterobacteriaceae families. Several of these isolates may have potential for development as biofertilizers or biopesticides for western Canadian legume crops.     

Three cell lines showing androgen-dependent, -independent,and-suppressed phenotypes,established from a single tumor of androgen-dependent shionogi carcinoma 115

Summary We investigated the heterogeneity of cells in terms of androgen responsiveness within a single tumor mass of Shionogi carcinoma SC-115 showing androgen-dependent growth. After cloning of the tumor by the limiting dilution method in the presence of androgen, we isolated 40 clones at random. Twenty-two clones required androgen for growth (androgen-dependent phenotype), 16 did not (androgen-independent phenotype), and the remaining two clones showed growth inhibition when androgen was added (androgen-suppressed phenotype). In addition, 22 androgen-dependent clones showed heterogeneity in growth factor sensitivity in the absence of androgen. All clones were sensitive to both acidic and basic fibroblast growth factor (FGF), 7 of 22 clones were sensitive to epidermal growth factor (EGS) and transforming growth factor (TGF)-α, and 2 of 22 clones were sensitive to TGF-β. This preexisting heterogeneity may be partly responsible for the growth of androgen-dependent tumor under hormone-deprived circumstances. Three typical clones, SC2G, SC1G, and SC4A, were selected from androgen-dependent, -independent, and-suppressed phenotypic groups, respectively. These clones, as well as original solid tumors, were found to produce heparin-binding growth factors of heterogeneous elution positions. The molecular nature of these growth factors is not yet known. Neither anti-basic FGF antibody nor anti-EGF antibody inhibited the cell growth when added in cell culture, suggesting the factors were distinct from basic-FGF and EGF.     

Dual nutrient limited growth: models, experimental observations, and applications

Dual nutrient limited growth, the control of the cell growth rate (kinetic aspect) or the restriction of the amount of biomass (stoichiometric aspect) by two nutrients at the same time, is a relatively unknown ability of the microorganisms and consequently, still not mentioned in textbooks to date. Nevertheless, multiple nutrient limited or controlled growth has been reported for different systems; e.g. ecosystems, batch, fed-batch, and chemostat cultures. Generally, dual nutrient limited growth has been observed when the microorganism of interest: (a) showed a variation of the cellular composition, (b) was able to accumulate a storage compound, (c) changed the cell metabolism, or (d) excreted metabolic intermediates. Consequently, stoichiometric models have been developed to estimate the growth conditions leading to dual nutrient limited growth. A general problem of the kinetic aspect is the accurate measurement of the growth controlling nutrients in the culture broth (microg l(-1) range), as the cells may consume residual nutrients during sampling. Nevertheless, most models of dual limited growth deal with the kinetic aspect although the control experiments are difficult to carry out. The aim of this survey is to introduce this special growth feature with respect to basic models, experimental data, and potential applications in bioprocesses.     

Interactions of cultured endothelial cells with TGF-beta, bFGF, PDGF and IGF-I

Endothelial cells in culture synthesize the growth factors transforming growth factor beta (TGF-beta), basic fibroblast growth factor (bFGF), platelet derived growth factor (PDGF) and, perhaps, insulin like growth factor I (IGF-I). We have previously demonstrated that IGF-I and PDGF have both high affinity receptors and stimulate glucose and AIB uptake in the microvessel cells under study and that IGF-I, but not PDGF, has similar high affinity receptors in cultured large vessel endothelial cells. In the present study, cultured bovine endothelial cells were exposed to these four growth factors to determine a) their effects on the acute metabolic processes of neutral amino acid (AIB) and glucose uptake and b) their interactions at the endothelial cell surface. In microvessel endothelial cells, each growth factor stimulated AIB and glucose uptake 2-4 fold whereas in large vessel endothelial cells only bFGF stimulated glucose uptake. Each growth factor had specific high affinity binding to the microvessel cells that was not influenced by the presence of the other growth factors. In large vessel endothelial cells, similar high affinity binding was present only for IGF-I and to a lesser degree TGF-beta. When cells were exposed to a given growth factor for 18 hours, homologous receptor downregulation was observed, with a maximal 60-95% decrease in surface binding. These findings suggest several potential levels of interaction of the growth factors TGF-beta, bFGF, PDGF and IGF-I in cultured vascular endothelial cells.     

Citrinolactones A, B and C, and Sclerotinin C, plant growth regulators from Penicillium citrinum

New plant growth regulators, named citrinolactones A (1), B (2) and C (3) and sclerotinin C (4), were isolated from Penicillium citrinum and their structures established by spectroscopic methods including 2D NMR. Compounds 1 and 4 increased root growth in proportion to their concentration from 3 to 300 mg/l. In contrast, 2 completely inhibited root growth at a concentration of 300 mg/l and 3 did not show any effect on root growth in a concentration range of 3-300 mg/l.     

Influence of Cadmium, Zinc, and Lead on Growth, Trap Formation, and Collagenase Activity of Nematode-Trapping Fungi

Growth and morphogenesis of seven species of nematode-trapping fungi and the activity of a collagenase produced by Arthrobotrys amerospora were measured in the presence of various concentrations of divalent cadmium, zinc, or lead. In general, growth varied with species and was dependent on the metal present and the concentration at which it was tested. Cadmium was found to exhibit the greatest toxicity followed by zinc and lead, respectively. In most cases, inhibition of growth was directly correlated with a decreased capacity to form traps. However, in a few cases, trap formation was inhibited either more or less than was growth. The activity of the collagenase was less sensitive than was growth or trap formation to heavy-metal inhibition.     

Arachidonic Acid Metabolites in bFGF-, PDGF-, and Serum-Stimulated Vascular Cell Growth

The signal transduction pathways through which growth factors regulate vascular cell growth are not fully understood. Recent studies suggest that metabolites of the lipoxygenase pathway may be involved in vascular cell growth. We have measured the effect of the lipoxygenase pathway inhibitors nordihydroguiaretic acid (NDGA), 5,6-dehydroarachidonic acid, and baicalein on bovine capillary endothelial cell (EC) and aortic smooth muscle cell (SMC) growth in the presence or the absence of growth factors. NDGA totally suppressed serum-stimulated EC and SMC growth as well as growth factor-stimulated proliferation over a 9-day time course. Removal of the inhibitor revealed that the inhibitory effect of NDGA was reversible and not due to cytotoxicity. The morphology of NDGA-treated EC was changed in a reversible manner from the characteristic polygonal to spindle shape. The 5-lipoxygenase inhibitor 5,6-dehydroarachidonic acid had no effect on vascular cell proliferation, but inhibition of 12-lipoxygenase with baicalein blocked both EC and SMC cell growth in a dose-dependent manner, in the presence and the absence of growth factors. Indomethacin, an inhibitor of the cyclooxygenase pathway, had no effect on EC and SMC proliferation. Quinacrine and oleyloxyethylphosphorycholine inhibition of the phospholipase A₂-catalyzed release of arachidonic acid from membrane phospholipids blocked growth factor- and serum-stimulated proliferation of EC and SMC. These results suggested that arachidonic acid metabolites are critical intermediaries in the regulation of vascular cell growth.     

Spatial and Temporal Variability in Juvenile Pacific Herring, Clupea pallasi, Growth in Prince William Sound, Alaska

We examined the spatial and temporal variability of juvenile Pacific herring, Clupea pallasi, growth within Prince William Sound, Alaska. Pacific herring, ranging from post-larval to mature fish, were collected from four spatially segregated bays between October 1995 and March 1998. Linear growth equations from each bay were similar. However, growth rates and wet weight-at-length, reflecting condition, of juvenile Pacific herring cohorts varied seasonally and annually. The short term spatial variability in juvenile Pacific herring growth suggested that each bay was a unique nursery area. The physical and biological conditions within each bay appeared to dictate Pacific herring growth rate.