scholarly journals Germination Characteristics of Thin-leaved Huckleberry (Vaccinium membranaceum)

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 538B-538
Author(s):  
Danny L. Barney
Keyword(s):  
Bacterial Contamination ◽  
Exponential Phase ◽  
Lower Percentage ◽  
Lag Phase ◽  
Cold Stratification ◽  
Surface Sterilization ◽  
Germination Characteristics ◽  
Vaccinium Membranaceum ◽  
Petri Dishes ◽  
Germinating Seeds

Seeds of V. membranaceum germinated in petri dishes fresh (undried), airdried for 7 days, or cold-stored for 1 or 6 years exhibited similar germination vs. time curves. Dry storage at 0–4°C for 1 or 6 years did not reduce the percentage of germination compared to fresh seeds. Cold stratification at 0–4°C slowed germination by extending the initial lag phase compared to unstratified seed. Stratification for 28 to 56 days delayed germination by ≈2 weeks. This pattern held true for fresh (undried) seed, seed air-dried for 7 days, and seed cold-stored for 6 years. Surface sterilization for 20 or 30 minutes with a 0.5% aqueous solution of sodium hypochlorite reduced fungal and bacterial contamination of germinating seeds without adversely impacting germination. Treatment of V. membranaceum seeds with captan or mancozeb fungicide inhibited germination by extending the lag phase and reducing the germination vs. time slope of the exponential phase. Mancozeb-treated seeds exhibited a lower percentage of germination than did controls, and often developed necrotic radical tips.

scholarly journals Potential Propagation by Seed and Cuttings of the Azorean NativeCalluna vulgaris(L.) Hull

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Maria João Pereira ◽  
Helena Fagundo ◽  
Tiago Menezes ◽  
João Couto
Keyword(s):  
Room Temperature ◽  
Seed Storage ◽  
Calluna Vulgaris ◽  
Landscape Conservation ◽  
Wild Populations ◽  
Surface Sterilization ◽  
Cultural Conditions ◽  
Germination Characteristics ◽  
Seed Age ◽  
Natural Stands

This work investigates the potential propagation by seed and cuttings of the Azorean nativeCalluna vulgaris(L.) Hull. for landscape conservation. With that purpose we have performed several germination and cuttings trials, using plant material from wild populations of this species. In the germination trials, we tested the effects of photoperiod length (8 and 16 h), temperature (10, 15, 20, and 20–10°C), seed age (6, 108, and 270 days), temperature of seed storage (4°C and room temperature), and seed surface sterilization on the germination characteristics. In the cuttings trials, we tested the effects of stem cutting type, cultural conditions, cuttings’ harvest month, and rooting substrates on the rooting percentages. The best percentages of germination, 93 and 90%, were obtained with fresh seeds and surface sterilized and sown under an 8 h photoperiod and with temperatures of 10°C or 15°C, respectively; germination after seed storage during 270 days is significantly superior (71%) when seeds are stored at 4°C. The best percentages of rooting were achieved for straight (96%) or heel cuttings (90%) harvested in March, planted on soil from natural stands ofC. vulgarisandErica azoricaHochst., outdoors in half shade, and partially covered with transparent polyethylene film.

scholarly journals GAMMA GLOBULIN PRODUCTION IN GERMFREE RATS AFTER BACTERIAL CONTAMINATION

1959 ◽  
Vol 110 (5) ◽  
pp. 675-684 ◽  
Author(s):  
Bengt E. Gustafsson ◽  
Carl-Bertil Laurell
Keyword(s):  
Bacterial Contamination ◽  
Gamma Globulin ◽  
Microbial Flora ◽  
Lag Phase ◽  
Bacterial Cells ◽  
Newborn Rats ◽  
Growing Rats ◽  
Different Types ◽  
Germfree Rats ◽  
Normal Microbial Flora

The earlier observed pronounced hypogammaglobulinemia in germfree rats of different ages has been confirmed. Using an immunologic technique the concentration of immunologic gamma globulins were found to vary between 10 and 15 per cent of the values observed in ordinary rats. Upon contamination of germfree rats with the normal microbial flora a pronounced lag phase was noted before the gamma globulin level became normal. This lag phase was most pronounced in growing rats. Newborn rats seem to start gamma globulin production more rapidly than older germfree rats. The response with regard to gamma globulin production on contamination of germfree rats with different types of bacterial cells through the natural routes is not identical.

scholarly journals An improved device for sampling bacterial populations on blankets

1960 ◽  
Vol 58 (2) ◽  
pp. 157-158 ◽  
Author(s):  
A. B. McQuade ◽  
W. J. A. Sutherland
Keyword(s):  
Surface Properties ◽  
Fibrous Material ◽  
Bacterial Contamination ◽  
Agar Plate ◽  
Simple Method ◽  
Bacterial Populations ◽  
Agar Surface ◽  
Petri Dishes ◽  
Routine Sampling ◽  
Hospital Wards

One of the major difficulties in determining the cleanliness of blankets for use in hospital wards is the estimation of bacterial contamination remaining on the blanket after washing. Present procedures are either cumbersome or not readily reproducible. Procedures for measuring bacterial contamination on fabrics may be based on dispersion of the bacteria as an aqueous or as an airborne cloud. As aerial sampling has the advantages that it may be rapid and simple and can be used to sample blankets which have been washed with a bactericide the possibilities of this principle were investigated. A simple method has been developed (Blowers & Wallace, 1955) in which the blanket is scraped manually by the edge of an agar plate so that the bacterial dust is thrown on to the exposed agar surface, but this procedure is difficult to control. There are wide differences in surface properties of blankets, and consequently in the amount of fibrous material shaved off by the Petri dishes. Puck, Robertson, Wise, Loosli & Lemon (1946) worked on the principle of hitting an area of taut blanket and sampling the aerial cloud so formed, but as their apparatus was not convenient for routine sampling in wards an improved version has been developed.

Design of a seed surface disinfection apparatus

1993 ◽  
Vol 73 (1) ◽  
pp. 159-161
Author(s):  
M. D. Pahl
Keyword(s):  
Key Words ◽  
Bacterial Contamination ◽  
Surface Disinfection ◽  
Seed Surface ◽  
Germinating Seeds

Accurate germination tests often require control of fungal and bacterial contamination in germinating seeds. However, disinfection of seed surfaces to reduce contamination can be time consuming. A new seed surface disinfection apparatus was designed to save time and reduce the variability between seed lots. Key words: Germination tests, seed surface disinfection

scholarly journals Induction of a Global Stress Response during the First Step of Escherichia coli Plate Growth

2006 ◽  
Vol 73 (3) ◽  
pp. 885-889 ◽  
Author(s):  
Caroline Cuny ◽  
Ma�al�ne Lesbats ◽  
Sam Dukan
Keyword(s):  
Solid Medium ◽  
Physiological State ◽  
Luria Bertani ◽  
Medium Composition ◽  
Exponential Phase ◽  
Lag Phase ◽  
Wild Type ◽  
Two Dimensional Electrophoresis ◽  
And Oxidative Stress ◽  
Dimensional Electrophoresis

ABSTRACT We have investigated the first events that occur when exponentially grown cells are transferred from a liquid medium (Luria-Bertani [LB]) to a solid medium (LB agar [LBA]). We observed an initial lag phase of 180 min for the wild type MG1655 without any apparent growth. This lack of growth was independent of the bacterial physiological state (either the stationary or the exponential phase), the solid medium composition, or the number of cells on the plate, but it was dependent on the bacterial genotype. Using lacZ-reporter fusions and two-dimensional electrophoresis analysis, we observed that when cells from exponential-phase cultures were plated on LBA, several global regulons, like heat shock regulons (RpoH, RpoE, CpxAR) and oxidative-stress regulons (SoxRS, OxyR, Fur), were immediately induced. Our results indicate that in order to grow on plates, bacteria must not only adapt to new conditions but also perceive a real stress.

scholarly journals Identification of Best Surface Sterilization Treatment and Control of Endophytic Bacterial Contamination in Annona squamosa L.

2019 ◽  
pp. 1-10
Author(s):  
Dipal Minipara ◽  
Hareshkumar Dhaduk ◽  
Ghanshyam Patil ◽  
Subhash Narayanan ◽  
Sushil Kumar
Keyword(s):  
Bacterial Contamination ◽  
Axenic Culture ◽  
Shoot Tip ◽  
Surface Sterilization ◽  
Survival Percentage ◽  
Surface Contaminants ◽  
Mature Node ◽  
Fungal Contaminants ◽  
And Control ◽  
Culture Protocol

Surface sterilization is most important step in plant tissue culture protocol. In the present investigation, an attempt was made to eliminate microbial and fungal contaminants from the surface and interior of plant material, thus obtaining axenic culture with highest survival rate. Sequential surface sterilizations of hypocotyl, leaf, shoot tip and mature node were carried out to investigate its effectiveness in controlling surface contamination with satisfactory survival of explants. Combination of different surfactant were used for surface sterilization treatments. The least contamination was obtained when hypocotyl explants were treated with 200 ppm cefotaxime and 500 ppm carbendazim along with 0.1% HgCl2 with best survival percentage. Treatments consisting of alcohol treatment, carbendazim (2000 ppm) followed by 1000 ppm cefotaxime, 500 ppm kanamycin, 2% sodium hypochloride and 0.1% HgCl2 sequentially resulted in complete elimination of surface contaminants from shoot tip, soft node and hard node obtained from field grown mature tree. Optimal elimination of bioburden from young leaf (77.38%) were obtained using 1000 ppm carbendazim, 500 ppm cefotaxime, 500 ppm kanamycin and 0.1% HgCl2. Gentamicin used in the medium was able to control the endophytic bacterial bioburden completely in the first cycle of 15 days itself at higher concentration of 96 mol/l to remove endophytic bacterial contamination with out effecting plant growth.

scholarly journals NUTRIENT MEDIUM SELECTION AND OPTIMIZATION OF AVIBACTERIUM PARAGALLINARUM DEEP CULTURE METHOD

2019 ◽  
pp. 12-16
Author(s):  
M. S. Firsova ◽  
V. A. Yevgrafova ◽  
A. V. Potekhin
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Phase ◽  
Nutrient Medium ◽  
Specific Growth ◽  
Exponential Phase ◽  
Exponential Growth Phase ◽  
Lag Phase ◽  
Optimal Method ◽  
Avibacterium Paragallinarum

Different liquid nutrient media supplemented with growth factors intended for Avibacterium paragallinarum strain No. 5111 cultivation were com­pared. The highest specific growth rate (μ = 0.787 ± 0.041 h-1) and the maximal accumulation of the agent’s biomass (Х = 9.52 ± 0.04 lg CFU/ cm3) were reported when cultured in casein soybean broth. Herewith, the mean time of the live microbial cell concentration doubling was minimal (td = 0.88 h), and the exponential growth phase lasted for 6 hours. The optimal method for Avibacterium paragallinarum cultivation in casein soy­bean broth in laboratory bioreactor Biotron LiFlus GX was determined through the measurements and adjustment of basic physical and chemical parameters. The time period until the culture reached the stationary growth phase was maximal with aeration at 1.0 l/min; herewith, the O2 partial pressure in the nutrient medium did not exceed 25%. The period of the intense decrease of medium’s pH was accompanied with the exponential phase of the bacterial growth. The nutrient medium’s pH ranging from 7.30 ± 0.02 to 7.90 ± 0.06 had no significant impact on the specific growth rate of the strain and the lag phase duration was minimal – 0.36–0.45 h. The strain cultivation in the nutrient medium with pH 7.90 ± 0.06 demonstrated maximal aggregation of the bacteria (9.76 ± 0.04 lg CFU/cm3). 40% glucose solution added at 0.6-0.8 g/l during cultivation facilitated the decrease of the suspension’s pH. Minimal redox value (–75 mV) was indicative of the completion of the exponential phase of the strain growth.  

scholarly journals A System for Controlling Water Potential in Seed Germination Research

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 364-366 ◽  
Author(s):  
Phil S. Allen ◽  
Donald B. White ◽  
Karl Russer ◽  
Dave Olson
Keyword(s):  
Water Vapor ◽  
Seed Germination ◽  
Water Potential ◽  
Constant Temperature ◽  
Filter Paper ◽  
Water Reservoir ◽  
Vapor Pressures ◽  
Salt Solutions ◽  
Petri Dishes ◽  
Germinating Seeds

An inexpensive system for maintaining desired water potentials throughout seed germination was developed. During hydration, a water reservoir at the base of inclined petri dishes allowed continual saturation of filter paper on which seeds were placed. During dehydration, seeds were exposed to equilibrium vapor pressures above saturated salt solutions. Constant temperature, necessary to prevent condensation of water vapor, was achieved via a small (0.2 A) fan that furnished and circulated heat throughout an insulated chamber in which salt solutions were placed. By operating the chamber above ambient laboratory temperature, interior cooling was not required. The system allowed manipulation of the rate, degree, and frequency of dehydration episodes to which germinating seeds were exposed.

scholarly journals The metabolic profile of lag and exponential phases of Saccharomyces cerevisiae growth changes continuously

2016 ◽  
Author(s):  
Rafael N. Bento ◽  
Miguel A. Aradhya ◽  
Valdir A. R. Semedo ◽  
Carlos E. S. Bernardes ◽  
Manuel E. M. Piedade ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metabolic Profile ◽  
Environmental Changes ◽  
Exponential Phase ◽  
Cellular Growth ◽  
Lag Phase ◽  
Continuous Increase ◽  
Flow Microcalorimetry ◽  
Growth Changes ◽  
Two Phases

AbstractCellular growth is usually separated in well-defined phases. For microorganism like Saccharomyces cerevisiae, two phases usually defined are (1) a lag phase, in which no growth is observed and cells adapt to a new environment, followed by (2) an exponential phase, in which rapid proliferation occurs. Here we investigate whether these well-defined phases are uniform. By using flow-microcalorimetry, we found that the metabolic profile of the culture is continuously changing, both in the lag and exponential phases of growth. Along the lag phase there is a continuous increase in the energy that is dissipated irreversibly as heat, while in the exponential phase the opposite occurs. We also confirm recent observations that the oxidative component of metabolism decreases along the exponential phase. Interestingly, nutrient limitation further decreases the amount of energy that is dissipated irreversibly. Altogether, this points to a picture in which cells respond rapidly to minute environmental changes by adjusting their metabolic profile.

scholarly journals Standardization of surface sterilization protocols for culture establishment in banana cv. Karpurachakkarakeli(AAB) male flower budsin vitro

2021 ◽  
Keyword(s):  
Bacterial Contamination ◽  
Male Flower ◽  
Surface Sterilization ◽  
Flower Meristem ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Short Time ◽  
Banana Flower ◽  
Banana Cultivar

Plant tissue culture is a proven technique for producing banana seeds in large quantities, uniformly and in a short time to support good quality banana seeds. The banana flower meristem can be a potential explant. The banana flower meristem offers the opportunity to regenerate plants with agronomic characteristics. This study aimed to regenerate banana flowers in vitro with different sucrose and BA (Benzyladenine) concentrations after standardized surface sterilization protocols. The study used a Completely Randomized Design (CRD), two factorial designwith surface sterilents and gelling agents. The results showed that the treatmentT15 (Sodium hypochlorite (1%) + HgCl2 (0.1%)) in G1 (0.25% gelrite) recorded the lowest fungal and bacterial contamination (0.00, 0.00) & (0.73, 0.53) respectively, in in vitro cultures of male flower buds of banana cultivar KarpuraChakkarakeli (AAB). While, the combination of BA (4 mgL-1) and sucrose (30 mgL-1) concentration had directly induced organogenesis in banana male flower explants.

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