Fertilization biology of the abalone Haliotis laevigata: laboratory and field studies

1999 ◽  
Vol 56 (9) ◽  
pp. 1668-1678 ◽  
Author(s):  
Russ Babcock ◽  
John Keesing
Keyword(s):  
Field Experiments ◽  
Nearest Neighbor ◽  
Field Studies ◽  
Fertilization Success ◽  
Limiting Factor ◽  
Fertilization Rates ◽  
Abalone Species ◽  
Nearest Neighbor Distances

A combination of laboratory and field experiments with the commercial abalone species Haliotis laevigata showed that fertilization may be a limiting factor in some exploited populations when distances separating spawning individuals are too large. The effects of gamete age, gamete concentration, and gamete contact time in the laboratory were used to model fertilization success in situ and compared with experimental fertilization rates in the field. Highest fertilization rates in vitro (80%) were found for sperm concentrations in the range of 1 × 104 to 1 × 106·mL-1. Fertilization rates of 48 ± 1.7% (95% CI) were measured at separation distances of 2 m and dropped to 2.8 ± 0.7% (95% CI) at 16 m downstream, agreeing closely with rates predicted by the model. Recruitment failures reported for South Australian populations of H. laevigata have occurred when densities fell below ca.0.3 animals·m-2, or mean nearest-neighbor distances between 1 and 2 m. This density corresponds well to critical nearest-neighbor distances for fertilization success. Stocks at higher densities are predicted to have higher fertilization rates (ca.90%) such that fertilization success is not a factor limiting recruitment.

scholarly journals In situ and in vitro estimation of mineral release from common feedstuffs fed to cattle

2017 ◽  
Vol 155 (7) ◽  
pp. 1160-1173 ◽  
Author(s):  
D. ZANETTI ◽  
A. C. B. MENEZES ◽  
F. A. S. SILVA ◽  
L. F. COSTA E SILVA ◽  
P. P. ROTTA ◽  
...  
Keyword(s):  
Release Rate ◽  
Soluble Fraction ◽  
Limiting Factor ◽  
Asymptotic Model ◽  
Mineral Absorption ◽  
Large Variability ◽  
Group 4 ◽  
Ruminal Degradation

SUMMARYThe objective of the current study was to quantify the dry matter (DM) digestibility, and total ash (TA) and mineral release from 12 concentrate and 12 forage feedstuffs commonly fed to cattle using in situ and in vitro methods. Concentrate and forage feedstuffs were incubated in the rumen of ruminally cannulated beef bulls at eight different time points. Two different trials were conducted for concentrates and forages, with maximum incubation time of 72 and 120 h, respectively. The residue from samples incubated for 24 h were treated with pepsin and hydrochloric acid to simulate abomasum digestion in vitro. The initial and residual samples after in situ and in vitro incubations were measured. An asymptotic model was adopted for estimating solubility of minerals, disappearance rate of DM, and TA. Correlations between feedstuff contents and mineral release were evaluated. Residual samples from rumen fermentation after 24 h were incubated in simulated abomasal conditions and mineral release was measured. Cluster analysis was performed to group feedstuffs in relation to TA release. Large variability was observed between concentrate and forage feedstuffs for all constituents analysed. Large variability was observed for the effective ruminal degradation of TA and individual mineral release. When feedstuffs were clustered according to the immediately soluble fraction (‘a’), the insoluble by potentially releasable fraction (‘b’) and the release rate of ‘b’ (‘kd’,/h) estimates of TA ruminal release, four groups were identified. From group ‘1’ to group ‘4’, an increase in the soluble fraction and a reduction in both moderate releasable fraction and release rate was observed. Neutral detergent fibre content had a negative correlation with mineral release in the rumen, while mineral content had a positive correlation. These results demonstrate that mineral solubilization in the digestive tract is not the limiting factor for mineral absorption from the feedstuffs tested.

In Situ Models, Physico-Chemical Aspects

1994 ◽  
Vol 8 (2) ◽  
pp. 125-133 ◽  
Author(s):  
J.M. Ten Cate
Keyword(s):  
Single Point ◽  
Limiting Factor ◽  
Model Parameters ◽  
Laboratory Findings ◽  
Physiological Processes ◽  
Physico Chemical ◽  
Crystallite Surface ◽  
Mineral Loss

In situ (intra-oral) caries models are used for two purposes. First, they provide information about oral physiological processes. Such information helps to detail our knowledge of the oral ecosystem and to verify conclusions from in vitro experiments. Second, in situ models are utilized to test preventive agents in the phase between laboratory testing and clinical trials. Most investigations involving enamel inserts have been aimed at testing new dentifrices. The experimental designs of such studies usually do not allow one to draw conclusions on physico-chemical processes, e.g., because of single point measurements. Studies of model parameters (lesion type, lesion severity, and de/remineralization in time) constitute only a minority of the research reports. The most striking observation obtained with in situ models has been the significant differences in de/remineralization observed among individuals and, more importantly, within one individual during different time periods and between different sites in the same mouth (for review, see ten Cate et al., 1992). Regardless of this, some general findings can be inferred: During in situ demineralization, up to 62 vol%μm/day may be removed from enamel. For dentin specimens, this value may be as high as 89 vol%μm/day. For remineralization, during fluoride dentifrice treatment, a median deposition rate of 0.7%/day (for lesions with integrated mineral loss values between 2000 and 4000 vol%μm) is found. The rate of deposition seems to be correlated with the extent of the pre-formedlesion. This suggests that the number of sites (crystallite surface) available for calcium phosphate precipitation is an important parameter. However, the rate at which mineral ions are supplied (by saliva) could also be a limiting factor, as is shown in a theoretical analysis of mass-balance of enamel constituents. The few studies that have monitored caries development in time reveal that mineral loss (and also lesion progression in depth) from enamel in situ is linear in time. This is in contrast to results from laboratory findings.

Corrosion and performance of dust palliatives : laboratory and field studies

2021 ◽  
Author(s):  
Lulu Edwards ◽  
Charles Weiss ◽  
J. Newman ◽  
Fred Nichols ◽  
L. Coffing ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Field Trials ◽  
Ground Vehicle ◽  
Wind Speeds ◽  
Corrosion Studies ◽  
Air Impingement ◽  
And Performance ◽  
Rotary Wing

This report details laboratory and field experiments on BioPreferred® dust suppressants to assess performance and corrosion characteristics. Numerous bio-based dust suppressant products are marketed, but little data are available to assess performance for dust abatement and corrosion of common metals. A laboratory study used an air impingement device and the Portable In-Situ Wind ERosion Laboratory (PI-SWERL) to simulate wind speeds similar to those in field conditions for rotary wing aircraft. Laboratory corrosion studies used metal coupons imbedded in soil treated with dust palliative. Field trials were conducted using ground vehicle traffic to minimize cost and lower safety concerns while increasing surface wear from repetitive traffic. These studies clearly show that bio-based products demonstrate low corrosion potential with similar dust abatement performance to synthetic-based agents.

In situ seed development and in vitro regeneration of three difficult-to-propagate Lepidosperma species (Cyperaceae)

2010 ◽  
Vol 58 (2) ◽  
pp. 107 ◽  
Author(s):  
Andrea Kodym ◽  
Shane Turner ◽  
John Delpratt
Keyword(s):  
In Vitro Culture ◽  
In Vitro Regeneration ◽  
Field Studies ◽  
Fruit Production ◽  
Germination Response ◽  
Immature Seeds ◽  
Short Period ◽  
Viable Seeds

Field studies of fruit production from Lepidosperma concavum R.Br., L. laterale R.Br. and L. longitudinale Labill. showed that large proportions (21–77%) of fruits were unfilled and that filled and unfilled fruits looked alike. Bagging of inflorescences demonstrated that filled fruits tended to be shed, while empty fruits remained within the inflorescence. Time of collection was critical for obtaining viable seeds, with successful harvesting limited to a short period (weeks) after maturation. The timing of flowering and fruit maturation were fairly consistent between species, populations and years in our study area. In L. concavum fruit production was increased in cultivation compared with wild populations. In all three species, very little or no germination of fruits occurred under nursery conditions. In vitro culture initiation was attempted using intact fruits, nicked fruits and seeds on 1/2MS (Murashige and Skoog) medium with 1 µM zeatin and 0.5 µM gibberellic acid in darkness. Culture of intact fruit resulted in no germination, while nicked fruit showed some germination response. Best results were achieved from seeds with germination occurring as early as 7 to 18 days depending on the species. Germination of L. concavum, L. laterale and L. longitudinale was 86%, 64% and 83% respectively within 5 weeks. Germination response was strongly influenced by seed maturity. Mature seeds germinated significantly faster than immature seeds. On a small proportion of cultured seeds, calli formed and differentiated into numerous plantlets on growth regulator-free medium. Given the promising results observed in this study, in vitro culture appears to be a practical means of mass propagating Lepidosperma species.

Biocontrol of Sclerotinia wilt of sunflower by Pseudomonas fluorescens and Pseudomonas putida strains

1995 ◽  
Vol 41 (8) ◽  
pp. 685-691 ◽  
Author(s):  
J. M. Expert ◽  
B. Digat
Keyword(s):  
Pseudomonas Putida ◽  
Pseudomonas Fluorescens ◽  
Sclerotinia Sclerotiorum ◽  
Field Experiments ◽  
In Vitro Tests ◽  
Significant Protection ◽  
Bacterial Strains ◽  
In Situ Tests

An increase in early injury to the roots and collar of sunflower plants caused by Sclerotinia sclerotiorum has been observed in France for several years. In vitro tests (inhibition of fungi and cyanide production by bacterial strains) and in situ tests (in nonsterile humus, in a growth chamber) were performed to screen the most efficient Pseudomonas fluorescens and Pseudomonas putida strains effective against this form of injury caused by S. sclerotiorum. Although there was no correlation between in vitro and in situ tests, a positive correlation between in situ tests and field experiments was obtained. At least 1 × 106 bacteria per seed were required for significant protection in in situ tests and field trials demonstrated that significant protection of sunflower was obtained by seed bacterization with selections of P. fluorescens and P. putida.Key words: biological control, Pseudomonas fluorescens, Pseudomonas putida, Sclerotinia sclerotiorum, sunflower, bacterization.

scholarly journals Zoospore Homing and Infection Events: Effects of the Biocontrol Bacterium Burkholderia cepacia AMMDR1 on Two Oomycete Pathogens of Pea (Pisum sativum L.)

2000 ◽  
Vol 66 (12) ◽  
pp. 5192-5200 ◽  
Author(s):  
K. Heungens ◽  
J. L. Parke
Keyword(s):  
Mutant Strain ◽  
Burkholderia Cepacia ◽  
Field Experiments ◽  
Sweet Corn ◽  
Inoculum Potential ◽  
Aphanomyces Euteiches ◽  
Pea Seeds ◽  
Roots In Vitro

ABSTRACT Burkholderia cepacia AMMDR1 is a biocontrol agent that protects pea and sweet corn seeds from Pythium damping-off in field experiments. The goal of this work was to understand the effect ofB. cepacia AMMDR1 on Pythium aphanidermatum andAphanomyces euteiches zoospore homing events and on infection of pea seeds or roots. In vitro, B. cepaciaAMMDR1 caused zoospore lysis, prevented cyst germination, and inhibited germ tube growth of both oomycetes. B. cepacia AMMDR1 also reduced the attractiveness of seed exudates to Pythiumzoospores to nondetectable levels. However, when present at high levels on seeds, B. cepacia AMMDR1 had little net effect on zoospore attraction, probably because it also enhanced seed exudation. Seed-applied B. cepacia AMMDR1 dramatically reduced the incidence of infection by Pythium zoospores in situ compared with an antibiosis-deficient Tn5 mutant strain. This mutant strain also decreased Pythium infection incidence to some extent, but only when the pathogen inoculum potential was low. B. cepacia AMMDR1 did not affect attraction ofAphanomyces zoospores or Aphanomyces root rot incidence. These results suggest that B. cepacia AMMDR1 controlsP. aphanidermatum largely through antibiosis, but competition for zoospore-attracting compounds can contribute to the effect. Differences in suppression of Aphanomyces andPythium are discussed in relation to differences in the ecology of the two pathogens.

scholarly journals Development of Tuber Blight (Phytophthora infestans) on Potato Cultivars Based on In Vitro Assays and Field Evaluations

HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1501-1508 ◽  
Author(s):  
Richard O. Nyankanga ◽  
Ocen Modesto Olanya ◽  
Hans C. Wien ◽  
Ramzy El-Bedewy ◽  
John Karinga ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Field Experiments ◽  
Field Studies ◽  
Potato Cultivars ◽  
In Vitro Assays ◽  
R Genes ◽  
Lesion Diameter ◽  
Foliar Blight ◽  
Tuber Blight

Tuber blight may result from infection of wounded or unwounded potato tubers exposed to sporangia from foliar blight, soil, or blighted tubers. However, there are limited data on the prediction of tuber blight in field or storage environment based on in vitro assays. To assess this relationship, potato cultivars with foliar blight resistance (R-genes) and general resistance were evaluated for tuber blight incited by Phytophthora infestans (US-1) based on wound-induced and unwounded tuber inoculations. Surface lesion diameter, lesion depth, and frequency distribution of blighted tubers were assessed in in vitro assays and tuber blight incidence determined in field experiments. Significant differences (P < 0.05) in lesion diameter and depth were recorded among cultivars. Surface lesion diameter, depth, and index ranged from 5 to 40, 2 to 16.3, and 15 to 656 mm, respectively, in wound-inoculated tubers. In nonwounded tuber assays, the incidence of blighted tubers ranged from 0% to 8.7% in both years. Tuber blight infection of potato cultivars varied between years in field studies. Although tuber infection differed among cultivars, the frequency of blighted tubers had a normal statistical distribution irrespective of R-genes, implying that foliar resistance may have limited effect on tuber blight occurrence based on in vitro experiments. Prediction of tuber blight based on inoculation assays can be effectively used to estimate and manage blight development in storage environments.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Application of Lattice Imaging Techniques to Amorphous Films

1975 ◽  
Vol 33 ◽  
pp. 8-9
Author(s):  
S. R. Herd ◽  
P. Chaudhari
Keyword(s):  
Nearest Neighbor ◽  
Random Network ◽  
Imaging Techniques ◽  
Network Models ◽  
Accurate Method ◽  
Direct Transmission ◽  
Lattice Imaging ◽  
Transmission Electron ◽  
Lattice Planes ◽  
Nearest Neighbor Distances

Electron diffraction and direct transmission have been used extensively to study the local atomic arrangement in amorphous solids and in particular Ge. Nearest neighbor distances had been calculated from E.D. profiles and the results have been interpreted in terms of the microcrystalline or the random network models. Direct transmission electron microscopy appears the most direct and accurate method to resolve this issue since the spacial resolution of the better instruments are of the order of 3Å. In particular the tilted beam interference method is used regularly to show fringes corresponding to 1.5 to 3Å lattice planes in crystals as resolution tests.

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