In vitro branching in relation to repeated subculture in two cultivars of Potentilla fruticosa

1993 ◽  
Vol 32 (2) ◽  
pp. 235-240 ◽  
Author(s):  
W. R. Remphrey ◽  
C. E. Palmer ◽  
M. J. Blouw
Keyword(s):  
Potentilla Fruticosa ◽  
Repeated Subculture

Precipitation and seasonality affect grazing impacts on herbage nutritive values in alpine meadows on the Qinghai-Tibet Plateau

2019 ◽  
Vol 12 (6) ◽  
pp. 993-1008 ◽  
Author(s):  
Xixi Yao ◽  
Jianping Wu ◽  
Xuyin Gong
Keyword(s):  
Nutritional Value ◽  
Dominant Species ◽  
Nutritive Value ◽  
Growing Season ◽  
Tibet Plateau ◽  
Nutritional Values ◽  
Potentilla Fruticosa ◽  
Nutritive Values ◽  
Qinghai Tibet Plateau

AbstractAimsGrasslands used for animal husbandry are chosen depending on the nutritive values of dominant herbage species. However, the influence of grazing in combination with precipitation and growing season on the nutritive values of dominant species has not been explicated.MethodsTo unveil the influence of the different grazing intensities on the nutritional values, an ecological study was formulated, namely fencing (G0), light grazing (G1), moderate grazing (G2) and high grazing (G3). This ambitious study was undertaken on the nutritive values of the four dominant species of herbage in an alpine meadow on the Qinghai-Tibet Plateau (QTP) during growing season (June–September) for two successive years, namely 2015 (rainy year) and 2016 (droughty year).Important FindingsWe found that (i) the nutritive value of Kobresia capillifolia, Polygonum viviparum and Caragana sinica was noticeably increased by grazing, but negligible effect on Potentilla fruticosa nutritive value was recorded. (ii) During the rainy year (2015), compared with G0, Polygonum viviparum and Potentilla fruticosa displayed 5.4 and 1.5% increases in the crude protein (CP) content and 8.5 and 2.4% increases in vitro true digestibility (IVTD), respectively, while the neutral detergent fibre (NDF) decreased by 13.5 and 0.9%, respectively. During the droughty year (2016), compared with G0, C. sinica and Potentilla fruticosa showed increases in the CP content by 4.3 and 1.3% and increases in the IVTD by 10.7 and 0.4%, respectively, during G3, while the NDF decreased by 6.0 and 1.0%, respectively. (iii) The nutritive values of all species were higher in the years when the rains were good. However, the nutritive values suffered heavily during drought conditions. Besides, the highest and lowest values of nutrition were detected in June and in September, respectively. The inter-seasonal and the inter-annual changes in the nutritional values of species were higher for K. capillifolia and Polygonum viviparum than for Potentilla fruticosa and C. sinica, suggesting that Potentilla fruticosa and C. sinica had higher water-use efficiency. (iv) Grazing clearly reduced the drought tolerance of three species and showed no effects on Potentilla fruticosa. (v) Grazing clearly increased the inter-month variation in the nutritional value of K. capillifolia and Polygonum viviparum but showed no effects on Potentilla fruticosa or C. sinica. Evidently, the grazing effects impacting the nutritional value of the dominant species of herbage exhibited conspicuous inter-annual and seasonal variations with species-specific influences and responses. Our findings are expected to have far-reaching implications enabling the authorities to arrive at strategic decisions and designing of relevant policies for the efficient management of the ecosystems ensuring the speed restoration of the QTP under severe grazing and extreme climatic circumstances.

scholarly journals Evaluating the Rapid Emergence of Daptomycin Resistance in Corynebacterium: A Multi-Center Study

2021 ◽  
Author(s):  
Kaitlin F. Mitchell ◽  
Erin McElvania ◽  
Meghan A. Wallace ◽  
Lauren E. Droske ◽  
Amy E. Robertson ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Exposure Period ◽  
Corynebacterium Striatum ◽  
Before And After ◽  
Multi Center Study ◽  
High Level ◽  
The Impact ◽  
Repeated Subculture ◽  
Center Study

Background: Members of the genus Corynebacterium are increasingly recognized as pathobionts and can be very resistant to antimicrobial agents. Previous studies have demonstrated that Corynebacterium striatum can rapidly develop high-level daptomycin resistance (HLDR) (minimum inhibitory concentration [MIC] ≥256 μg/mL). Here we conducted a multi-center study to assay for this in vitro phenotype in diverse Corynebacterium species. Methods: Corynebacterium clinical isolates (n=157) from four medical centers were evaluated. MIC values to daptomycin, vancomycin, and telavancin were determined before and after overnight exposure to daptomycin to identify isolates able to rapidly develop daptomycin non-susceptibility. To investigate assay reproducibility, 18 isolates were evaluated at three study sites. In addition, stability of daptomycin non-susceptibility was tested using repeated subculture without selective pressure. The impact of different media brands was also investigated. Results: Daptomycin non-susceptibility emerged in 12 of 23 species evaluated in this study (C. afermentans, amycolatum, aurimucosum, bovis, jeikeium, macginleyi, pseudodiphtheriticum, resistens, simulans, striatum, tuberculostearicum, and ulcerans) and was detected in 50 of 157 (31.8%) isolates tested. All isolates displayed low (susceptible) MIC values to vancomycin and telavancin before and after daptomycin exposure. Repeated subculture demonstrated 2 of 9 isolates (22.2%) exhibiting HLDR reverted to a susceptible phenotype. Of 30 isolates tested on three media brands, 13 (43.3%) had differences in daptomycin MIC values between brands. Conclusions: Multiple Corynebacterium species can rapidly develop daptomycin non-susceptibility, including HLDR, after a short daptomycin exposure period.

scholarly journals Hydrophobicity and adherence of oral streptococci after repeated subculture in vitro.

1983 ◽  
Vol 40 (1) ◽  
pp. 432-435 ◽  
Author(s):  
G Westergren ◽  
J Olsson
Keyword(s):  
Oral Streptococci ◽  
Repeated Subculture

scholarly journals Clonal Propagation of Rhynchostylis retusa (Lin.) Blume through in vitro Culture and their Establishment in the Nursery

2012 ◽  
Vol 22 (1) ◽  
pp. 1-11
Author(s):  
Pinaki Sinha ◽  
Miskat Ara Akhter Jahan
Keyword(s):  
Plant Tissue ◽  
Activated Charcoal ◽  
High Frequency ◽  
Nutrient Medium ◽  
Clonal Propagation ◽  
Nodal Segments ◽  
Nursery Plant ◽  
Half Strength ◽  
Repeated Subculture

For high frequency regeneration of Rhyncnostylis retusa (Lin.) Blume apical nodal segments were used. Half strength MS + 2% sucrose + 1.5 mg/l BA + 0.5 mg/l NAA + 2 g/l peptone + 10% (v/v) coconut water (CW) + 0.5 g/l activated charcoal (AC) was the best nutrient medium, on which 89% cultures induced 8 microshoots per culture. Subculture of microshoots for further 8 weeks on the same nutrient medium enhanced the number of microshoots up to 95. For further proliferation of microshoots, their development into shoots as well as formation of secondary microshoots from the base of the old ones, the best medium was half strength of MS + 2% sucrose + 2 g/l peptone + 10% (v/v) CW + 0.5 g/l AC + 150 mg/l L-glutamine. Plantlets with roots were obtained in half strength of  MS + 2% sucrose + 2 g/l peptone + 10% (v/v) CW + 0.5 g/l AC + 5.0  g/l banana powder, on which cent per cent shoots rooted within eight weeks. The pH of all the categories of cultures were maintained at 5.6 before adding 2.2 g/l gelrite and autoclaving, and the cultures were incubated at 2000 - 3000 lux for 16/8 hrs light/dark at 24 ± 2ºC. Regeneration of plantlets continued due to repeated subculture of microshoots and regenerants were acclimatized and established in the nursery. Plant Tissue Cult. & Biotech. 22(1): 1-11, 2012  (June) DOI: http://dx.doi.org/10.3329/ptcb.v22i1.11242 

scholarly journals Pengaruh jumlah subkultur dan media sub-optimal terhadap pertumbuhan dan kemampuan regenerasi kalus tebu (Saccharum officinarum L.) (Effect of Repeated Subculture and suboptimum media on the Growth of Sugarcane Calli (Saccharum officinarum L.))

2016 ◽  
Vol 84 (1) ◽  
Author(s):  
Hayati MINARSIH ◽  
. Suharyo ◽  
Imron RIYADI ◽  
Diah RATNADEWI
Keyword(s):  
Saccharum Officinarum ◽  
Coconut Water ◽  
Basic Medium ◽  
Callus Initiation ◽  
Young Leaves ◽  
Three Stages ◽  
Sugarcane Productivity ◽  
Repeated Subculture ◽  
Better Than

Sugarcane (Saccharum officinarum L.) is an important crop for sugar production. One attempt to increase sugarcane productivity is through micropropagation and quality improvement of sugarcane seedlings in vitro. This research aimed to study the effect of repeated subcultures on callus capacity for regeneration and plant survival in acclimatization phase, as well as the influence of suboptimum media on the recovery capability of sugarcane callus to proliferate in vitro. Fourth subcultured sugarcane callus derived from young leaves were used as material in this research. Basic medium of Murashige and Skoog (MS) added with 3 mg/L 2,4-D, 10% coconut water, and 3% sucrose was used for callus initiation. For callus regeneration, the MS medium was supplemented with 2 mg/L BAP, 0.2 mg/L IAA, 10% coconut water, and 3% sucrose. Study on the effect of subculture numbers consisted of three stages, i.e. initiation, regeneration, and acclimatization, while the study on resting phase or the use of sub-optimal media included six treatment media and two pathways. Results showed that the fifth subcultures produced embryoid callus (91%), the highest non mucilaginous callus (97%), and the highest abnormality rate (6%). Results from the suboptimum media treatment, showed that B pathway (4 week resting phase) was better than the A pathway (8 week resting phase), based on fresh weight and callus abnormality percentage. A and B pathways indicated that the growth of callus can be recovered when it was grown back to the normal media and 1.5D-MS treatment of the resting phase showed the best growth and appearance. 

scholarly journals Pengaruh jumlah subkultur dan media sub-optimal terhadap pertumbuhan dan kemampuan regenerasi kalus tebu (Saccharum officinarum L.) (Effect of repeated subculture and suboptimum media on the growth of sugarcane calli (Saccharum officinarum L.))

2016 ◽  
Vol 84 (1) ◽  
Author(s):  
Hayati MINARSIH ◽  
. Suharyo ◽  
Imron RIYADI ◽  
Diah RATNADEWI
Keyword(s):  
Saccharum Officinarum ◽  
Coconut Water ◽  
Basic Medium ◽  
Callus Initiation ◽  
Young Leaves ◽  
Three Stages ◽  
Sugarcane Productivity ◽  
Repeated Subculture ◽  
Better Than

Sugarcane (Saccharum officinarum L.) is an important crop for sugar production. One attempt to increase sugarcane productivity is through micropropagation and quality improvement of sugarcane seedlings in vitro. This research aimed to study the effect of repeated subcultures on callus capacity for regeneration and plant survival in acclimatization phase, as well as the influence of suboptimum media on the recovery capability of sugarcane callus to proliferate in vitro. Fourth subcultured sugarcane callus derived from young leaves were used as material in this research. Basic medium of Murashige and Skoog (MS) added with 3 mg/L 2,4-D, 10% coconut water, and 3% sucrose was used for callus initiation. For callus regeneration, the MS medium was supplemented with 2 mg/L BAP, 0.2 mg/L IAA, 10% coconut water, and 3% sucrose. Study on the effect of subculture numbers consisted of three stages, i.e. initiation, regeneration, and acclimatization, while the study on resting phase or the use of sub-optimal media included six treatment media and two pathways. Results showed that the fifth subcultures produced embryoid callus (91%), the highest non mucilaginous callus (97%), and the highest abnormality rate (6%). Results from the suboptimum media treatment, showed that B pathway (4 week resting phase) was better than the A pathway (8 week resting phase), based on fresh weight and callus abnormality percentage. A and B pathways indicated that the growth of callus can be recovered when it was grown back to the normal media and 1.5D-MS treatment of the resting phase showed the best growth and appearance. 

scholarly journals In Vitro Activities of Oral β-Lactams at Concentrations Achieved in Humans against Penicillin-Susceptible and -Resistant Pneumococci and Potential to Select Resistance

1998 ◽  
Vol 42 (8) ◽  
pp. 1973-1979 ◽  
Author(s):  
Christine E. Thorburn ◽  
Sarah J. Knott ◽  
David I. Edwards
Keyword(s):  
Streptococcus Pneumoniae ◽  
Bactericidal Effect ◽  
Penicillin G ◽  
Cross Resistance ◽  
Dosing Interval ◽  
Middle Ear Fluid ◽  
Amoxicillin Clavulanate ◽  
Time Kill ◽  
Repeated Subculture

ABSTRACT The β-lactam susceptibilities of 65 strains ofStreptococcus pneumoniae for which penicillin MICs covered a broad range were assessed. The order of potency was amoxicillin (AMX) = amoxicillin-clavulanate (AMC) > penicillin G > cefpodoxime (CPO) > cefuroxime (CXM) > cefprozil > cefaclor > loracarbef > cefixime. No decrease in susceptibility was seen following repeated subculture of two penicillin-susceptible strains of S. pneumoniae in AMX, AMC, cefaclor, or loracarbef, whereas repeated exposure to CPO and CXM resulted in 4- to 32-fold decreases in susceptibility for both strains. When one of these strains was exposed to concentrations of CPO, CXM, AMX, and AMC achieved in the serum of humans following the administration of an oral dose, all agents were rapidly bactericidal, with no decrease in susceptibility up to 72 h. This was consistent with antibiotic concentrations exceeding the MICs for 100% of the dosing interval. For a penicillin-resistant strain, MICs were exceeded for 29% of the 12-h dosing interval for 500 mg of AMX, 42% of the interval for AMC with 875 mg of AMX and 125 mg of clavulanate (875/125 mg of AMC) 21% of the interval for 500 mg of CXM, and 0% of the interval for 200 mg of CPO. Consequently, only 875/125 mg of AMC produced a sustained bactericidal effect. A four- to eightfold reduction in susceptibility to CPO and CXM and cross-resistance with cefotaxime, but not penicillin or AMC, were selected following exposure to simulated serum CPO and CXM concentrations. In addition, AMX and AMC were the only agents which consistently produced a >99% reduction in bacterial numbers in time-kill studies using concentrations of antibiotic achieved in middle ear fluid for all three strains of penicillin-resistant S. pneumoniae tested.

In vitro production and propagation of Fragaria vesca x Potentilla fruticosa hybrids

1996 ◽  
Vol 46 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Tara Silva ◽  
J. K. Jones
Keyword(s):  
Fragaria Vesca ◽  
In Vitro Production ◽  
Potentilla Fruticosa ◽  
Vitro Production

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

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