The effect of respiration on the phototactic behavior of the purple nonsulfur bacterium Rhodospirillum centenum

1997 ◽  
Vol 167 (2-3) ◽  
pp. 99-105 ◽  
Author(s):  
Simona Romagnoli ◽  
Alejandro Hochkoeppler ◽  
Lars Damgaard ◽  
D. Zannoni
Keyword(s):  
Rhodospirillum Centenum ◽  
Phototactic Behavior ◽  
Purple Nonsulfur Bacterium

IDENTIFICATION AND CHARACTERIZATION OF A PURPLE NONSULFUR BACTERIUM ISOLATED FROM COASTAL AREA OF HAI PHONG FOR USING IN PRODUCTION OF UNSATURATED FATTY ACID (OMEGA 6, 7, 9)

2019 ◽  
Vol 57 (6) ◽  
pp. 665 ◽  
Author(s):  
Yen Thi Hoang ◽  
Quynh Thi Thu Tran ◽  
Ha Hoang Chu ◽  
Tuyen Thi Do ◽  
Thanh Tat Dang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Unsaturated Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Nitrogen Sources ◽  
16S Rrna Analysis ◽  
Rhodovulum Sulfidophilum ◽  
Purple Nonsulfur Bacterium ◽  
High Lipid ◽  
Physiological Properties ◽  
Omega 6

Purple nonsulfur bacteria are a group that has so much biotechnological applications, particularly in producing of functional food rich with unsaturated fatty acids. A purple nonsulfur bacterium (named HPB.6) was chosen based on its strong growth, high lipid and synthesis of unsaturated fatty acid (omega 6,7,9). Studying on basic biological characteristics showed that the cells of HPB.6 were observed as ovoid-rod shape, none motility, Gram negative staining. The diameter of single bacterium was about 0.8-1.0 µm. The cells divide by binary fission and had bacteriochlorophyll a (Bchl a). This bacterium grew well on medium with carbon and nitrogen sources such as acetate, succinate, pyruvate, butyrate, glutamate, arginine, leucine, tyrosine, alanine, methionine, threonine, glutamine, yeast extract and NH4Cl. This selected strain grew well on medium with salt concentrations from 1.5 - 6.0% (optimum 3%), pH from 5.0 to 8.0 (optimum at pH 6.5) and could withstand Na2S at 4.0 - 5.2 mM. Based on morphological, physiological properties and 16S rRNA analysis received demonstrated that HPB.6 strain belongs to the species Rhodovulum sulfidophilum.

Nomenclature Abstract for Rhodospirillum centenum Favinger et al. 1994.

2003 ◽  
Author(s):  
Charles Thomas Parker ◽  
Sarah Wigley ◽  
George M Garrity ◽  
Nicole Danielle Osier
Keyword(s):  
Rhodospirillum Centenum

Time-Dependent Changes in Excitability After One-Trial Conditioning of Hermissenda

1997 ◽  
Vol 78 (6) ◽  
pp. 3460-3464 ◽  
Author(s):  
Terry Crow ◽  
Vilma Siddiqi
Keyword(s):  
Time Dependent ◽  
Control Group ◽  
Type B ◽  
Control Groups ◽  
Phototactic Behavior ◽  
Parallel Processes ◽  
Short And Long Term ◽  
A Site ◽  
Different Levels

Crow, Terry and Vilma Siddiqi. Time-dependent changes in excitability after one-trial conditioning of Hermissenda. J. Neurophysiol. 78: 3460–3464, 1997. The visual system of Hermissenda has been studied extensively as a site of cellular plasticity produced by classical conditioning. A one-trial conditioning procedure consisting of light paired with the application of serotonin (5-HT) to the exposed, but otherwise intact, nervous system produces suppression of phototactic behavior tested 24 h after conditioning. Short- and long-term enhancement (STE and LTE) of excitability in identified type B photoreceptors is a cellular correlate of one-trial conditioning. LTE can be expressed in the absence of STE suggesting that STE and LTE may be parallel processes. To examine the development of enhancement, we studied its time-dependent alterations after one-trial conditioning. Intracellular recordings from identified type B photoreceptors of independent groups collected at different times after conditioning revealed that enhanced excitability follows a biphasic pattern in its development. The analysis of spikes elicited by 2 and 30 s extrinsic current pulses at different levels of depolarization showed that enhancement reached a peak 3 h after conditioning. From its peak, excitability decreased toward baseline control levels 5–6 h after conditioning followed by an increase to a stable plateau at 16 to 24 h postconditioning. Excitability changes measured in cells from unpaired control groups showed maximal changes 1 h posttreatment that rapidly decremented within 2 h. The conditioned stimulus (CS) elicited significantly more spikes 24 h postconditioning for the conditioned group as compared with the unpaired control group. The analysis of the time-dependent development of enhancement may reveal the processes underlying different stages of memory for this associative experience.

scholarly journals Loss of Phototactic Behavior in Silkworm Larvae Reared on Synthetic Diet

1976 ◽  
Vol 52 (3) ◽  
pp. 137-140 ◽  
Author(s):  
Isamu SHIMIZU ◽  
Seiji KITABATAKE ◽  
Masaru KATO
Keyword(s):  
Silkworm Larvae ◽  
Phototactic Behavior ◽  
Synthetic Diet

In vitro associative conditioning of Hermissenda: cumulative depolarization of type B photoreceptors and short-term associative behavioral changes

1987 ◽  
Vol 57 (6) ◽  
pp. 1639-1668 ◽  
Author(s):  
J. Farley ◽  
D. L. Alkon
Keyword(s):  
Nervous System ◽  
B Cells ◽  
Hair Cell ◽  
B Cell ◽  
Behavioral Changes ◽  
Type B ◽  
Short Term ◽  
Phototactic Behavior ◽  
Optic Ganglion

Cumulative depolarization of Hermissenda type B photoreceptors, a short-term neural correlate of associative learning, was produced by simulating associative training in the isolated nervous system (in vitro conditioning). This simulation entailed stimulation and recording from three classes of neurons normally affected by the associative training procedure: a type B photoreceptor, the silent/excitatory (S/E) optic ganglion cell, and a statocyst caudal hair cell. Exposure of the isolated nervous system to five simultaneous pairings of light and current-induced impulse activity of the caudal hair cell resulted in an average 10-mV depolarization of type B cells. Cumulative depolarization was found to be pairing specific, to occur with a minimal number of training trials, and was paralleled by short-term pairing-specific changes in phototactic behavior for the intact animal. Two important determinants of cumulative depolarization were found to be the magnitude and duration of the long-lasting depolarization (LLD) response of type B cells to light, and a pairing-specific synaptic facilitation of the LLD response. The synaptic facilitation arose from two distinct sources: increased excitatory postsynaptic potential (EPSP) feedback on B cells following light and caudal hair cell stimulation pairings, and disinhibition of the type B photoreceptor following pairings. The S/E optic ganglion cell was found to be a potent regulator of B cell EPSPs. Cumulative depolarization was substantially reduced when the S/E cell was hyperpolarized throughout the course of pairings. Conversely, pairings of light with depolarizing current stimulation of the S/E cell were sufficient to produce cumulative depolarization of B cells. Precluding disinhibition of the B cell from the caudal hair cell was also found to attenuate cumulative depolarization. Additional constraints, inherent to the neural organization of the visual and statocyst neural systems were found to further limit the degree of cumulative depolarization. Among the most important of these were the interpairing interval and light intensity. Exposure of intact animals of five pairings of light and rotation resulted in short-term suppression of phototactic behavior. Like the cumulative depolarization of B cells with in vitro conditioning procedures, these changes were relatively pairing specific and persisted for comparable durations of time. Cumulative depolarization of B cells appears to be an important initial step in the production of long-term associative neural and behavioral changes in Hermissenda.

scholarly journals Analysis of a chemotaxis operon from Rhodospirillum centenum.

1997 ◽  
Vol 179 (18) ◽  
pp. 5712-5719 ◽  
Author(s):  
Z Y Jiang ◽  
C E Bauer
Keyword(s):  
Rhodospirillum Centenum
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