ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Preparation of stearoyl lactic acid ester catalyzed by lipases from Rhizomucor miehei and porcine pancreas optimization using response surface methodology (1999)

Kiran, K. R. ; Karanth, N. G. ; Divakar, S.

Springer

Applied microbiology and biotechnology 52 (1999), S. 579-584

add to mindlist on the mindlist

Details

ISSN: 1432-0614

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology

Notes: Abstract The esterification reaction between stearic acid and lactic acid using Rhizomucor miehei lipase and porcine pancreas lipase was optimized for maximum esterification using response surface methodology. The formation of the ester was found to depend on three parameters namely enzyme/substrate ratio, lactic acid (stearic acid) concentration and incubation period. The maximum esterification predicted by theoretical equations for both lipases matched well with the observed experimental values. In the case of R. miehei lipase, stearoyl lactic acid ester formation was found to increase with incubation period and lactic acid (stearic acid) concentrations with maximum esterification of 26.9% at an enzyme/substrate (E/S) ratio of 125 g mol−1. In the case of porcine pancreas lipase, esterification showed a steady increase with increase in incubation period and lactic acid (stearic acid) concentration independent of the E/S ratios employed. In the case of PPL, a maximum esterification of 18.9% was observed at an E/S ratio of 25 g mol−1 at a lactic acid (stearic acid) concentration of 0.09 M after an incubation period of 72 h.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002530051563

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

High efficiency transformation ofBrassica napus usingAgrobacterium vectors (1989)

Moloney, Maurice M. ; Walker, Janis M. ; Sharma, Kiran K.

Springer

Plant cell reports 8 (1989), S. 238-242

add to mindlist on the mindlist

Details

ISSN: 1432-203X

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract An efficient procedure for obtaining transgenicBrassica napus plants usingAgrobacterium binary vectors is described. The target tissue for the transformation is the cut end of cotyledonary petioles. These tissues, when cultured with their lamina intact, show a regeneration frequency of more than 80%. The cells of this cut surface, which undergo organogenesis, are very susceptible to topical infection byAgrobacterium. The cocultivation method used does not require feeder layers or use of exogenously applied promoters of virulence. After 72h of infection withAgrobacterium the explants were transferred to selective regeneration medium. Using kanamycin (15μg cm−3) for selection, transgenic plantlets emerged within 3 weeks. These plantlets which appeared on over half the explants were excised and rooted for a further 7–10 days. When the plants were large enough, leaves were taken for assay of NPT II activity using dot blots. Most of the plants surviving the selection showed substantial NPT II activity. The frequency of transformation and yield of transgenic plants was higher than in previously reported methods with this species. Southern blotting revealed that integration of the T-DNA frequently occurred in multiple copies and at multiple loci in the genome. The transgenicB. napus plants all grew normally and developed fertile flowers. The transgenic plants were self-pollinated and their progeny studied by two methods. The first was a single-embryo NPT II assay performed on developing seeds of these selfed-plants. The second was a leaf bleaching assay performed by selection of germinating seedlings of the selfed progeny. Both assays yielded segregation ratios consistent with the number of integration events indicated by Southern blots. The method should have broad application in studies of gene expression in theBrassicaceae and will be a cost-effective alternative to those seeking to improveBrassica crops by introduction of foreign genes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00778542

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Efficient shoot regeneration of Brassica campestris using cotyledon explants cultured in vitro (1991)

Hachey, John E. ; Sharma, Kiran K. ; Moloney, Maurice M.

Springer

Plant cell reports 9 (1991), S. 549-554

add to mindlist on the mindlist

Details

ISSN: 1432-203X

Keywords: Brassica campestris ; cotyledon culture ; histology ; organogenesis ; regeneration ; tissue culture

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary A system has been developed for efficient regeneration of shoots from Brassica campestris in vitro. Using 4-day old cotyledons with petioles as expiants and a combination of BA and NAA in the regeneration media, up to 70% of expiants produced shoots after 2 weeks in culture. The optimal conditions for regeneration were found to include a BA concentration of 2mgL−1 and NAA concentration of 1mgL−1. Light intensity had a profound effect on regeneration potential. The use of silver ions as an inhibitor of ethylene action reduced regeneration rates in this system. Rooting occured simultaneously with shoot formation on these media and the resultant shoots could be rooted readily on minimal medium. The genotype dependency was investigated and indicated that this method would be widely applicable to B. campestris cultivars. Regeneration of one cultivar, a high erucic acid type (R-500), was inefficient in the system described here. Histological studies indicated the development of multiple shoot primordia from the petiolar cut ends of the expiants after the initiation of meristematic activity in the cells about 100μm from the cut site within 2 days of culture initiation. The system described is compatible with previously reported Agrobacterium — mediated transformation protocols involving cotyledonary petioles.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00232329

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Micropropagation of western hemlock (Tsuga heterophylla [Raf.] Sarg.) from embryonic explants (1994)

Harry, Indra S. ; Lu, Chin-Yi ; Sharma, Kiran K. ; [et al.]

Springer

New forests 8 (1994), S. 1-13

add to mindlist on the mindlist

Details

ISSN: 1573-5095

Keywords: in vitro propagation ; organogenesis ; plantlet regeneration ; rooting ; Western hemlock

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract An in vitro propagation protocol is described for western hemlock, an important forestry species in Canada. For shoot bud induction, embryonic explants were placed initially on one-third strength Schenk and Hildebrandt medium containing 5 μM N6-benzyladenine (BA) or 5 μM BA in combination with either 5 μM kinetin or 5 μM 2-isopentenyl adenine for 14 days. The explants were transferred to basal medium without cytokinins for 3 weeks, and then to basal medium containing 0.05% activated charcoal. Elongating shoots were subcultured every 4 weeks on charcoal medium. Shoots, 10 mm in stem height, were rooted either in agar or sterilized peat/perlite (1:1). Up to 70% of the shoots formed roots when they were transferred to the latter, moistened with 1/2 strength Gresshoff and Doy medium containing 5 μM α-naphthaleneacetic acid. About 90% of the plantlets survived transfer to greenhouse conditions.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00034127

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

In vitro regeneration of shoot buds and plantlets from seedling root segments of Brassica napus L. (1989)

Sharma, Kiran K. ; Thorpe, Trevor A.

Springer

Plant cell, tissue and organ culture 18 (1989), S. 129-141

add to mindlist on the mindlist

Details

ISSN: 1573-5044

Keywords: Brassica napus ; organogenesis ; plantlet formation ; regeneration ; root segments ; shoot bud differentiation

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Root segments obtained from aseptically germinated seedlings of Brassica napus cv. Westar were used to optimize conditions for high-frequency shoot bud differentiation. The presence of low kinetin (0.5 μM) and relatively high indole-butyric acid (1.0 μM) levels facilitated optimum shoot bud differentiation. Modified MS medium (MMS) was superior to the other three basal media tested (MS, B5 and White's). Elevated sodium dihydrogen phosphate levels increased the differentiation of shoot buds. Increasing or decreasing the level of sucrose from 3% reduced the frequency of explants forming shoot buds. Addition of glutamine enhanced both the frequency of responding explants, as well as the number of shoots per responding explant. Root segments from 13-day-old seedlings produced the highest response (58%) in the presence of 100 mg l-1 glutamine. The position of the segment on the main root, size, and the presence or absence of lateral roots altered the morphogenic response. Sealing of the donor seedling cultures with Parafilm® instead of Stretch' n seal® resulted in a higher production of shoot buds, although root segment cultures were not affected by the type of sealing. Spontaneous rooting occurred on all developed shoots.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00033471

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

The role of cotyledonary tissue in the differentiation of shoots and roots from cotyledon explants of Brassica juncea (L.) Czern. (1991)

Sharma, Kiran K. ; Bhojwani, Sant S. ; Thorpe, Trevor A.

Springer

Plant cell, tissue and organ culture 24 (1991), S. 55-59

add to mindlist on the mindlist

Details

ISSN: 1573-5044

Keywords: auxin-like factor ; Brassica juncea ; brown mustard ; organogenesis ; regeneration ; tissue culture

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract In cotyledon cultures of Brassica juncea, shoots and roots invariable differentiate at the cut end of the petiole. Organogenesis occurred only if the proximal cut end of the petiole was in contact with the medium. In the absence of the petiole, differentiation from the lamina was rare. Hence investigations were carried out to study the influence of the cotyledonary lamina on regeneration of shoots and roots from the petiolar cut end. The lamina tissue was surgically removed from the cotyledon explants at different durations (0–10 days) after culturing them on either root-forming (basal medium) or shoot-forming (basal medium containing 5.0 μM N6-benzyladenine) media. The differentiation of roots or shoots from the petioles was dependent on the presence of the lamina for at least 7 days of culture. Quantitative removal of the laminar tissue had a corresponding negative effect on shoot bud differentiation from the petiole. The nature of the ‘lamina factor’ was found to be auxin-like.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00044266

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Unknown

Out-of-the-groove transport of lipids by TMEM16 and GPCR scramblases (2018)

Malvezzi, Mattia ; Andra, Kiran K. ; Pandey, Kalpana ; [et al.]

National Academy of Sciences

In: PNAS - Proceedings of the National Academy of Sciences of the United States of America. 2018; 115(30): E7033-E7042. Published 2018 Jun 20. doi: 10.1073/pnas.1806721115.

add to mindlist on the mindlist

Details

Publication Date: 2018-06-20

Description: Phospholipid scramblases externalize phosphatidylserine to facilitate numerous physiological processes. Several members of the structurally unrelated TMEM16 and G protein-coupled receptor (GPCR) protein families mediate phospholipid scrambling. The structure of a TMEM16 scramblase shows a membrane-exposed hydrophilic cavity, suggesting that scrambling occurs via the ‟credit-card” mechanism where lipid headgroups permeate through the cavity while their tails remain associated with the membrane core. Here we show that afTMEM16 and opsin, representatives of the TMEM16 and GCPR scramblase families, transport phospholipids with polyethylene glycol headgroups whose globular dimensions are much larger than the width of the cavity. This suggests that transport of these large headgroups occurs outside rather than within the cavity. These large lipids are scrambled at rates comparable to those of normal phospholipids and their presence in the reconstituted vesicles promotes scrambling of normal phospholipids. This suggests that both large and small phospholipids can move outside the cavity. We propose that the conformational rearrangements underlying TMEM16- and GPCR-mediated credit-card scrambling locally deform the membrane to allow transbilayer lipid translocation outside the cavity and that both mechanisms underlie transport of normal phospholipids.

Print ISSN: 0027-8424

Electronic ISSN: 1091-6490

Topics: Biology , Medicine , Natural Sciences in General