Lights on and action! Controlling microbial gene expression by light (Q37845235)

24 August 2017

1 reference

title

Lights on and action! Controlling microbial gene expression by light (English)

1 reference

24 August 2017

1

1 reference

Sonja Meyer zu Berstenhorst

24 August 2017

series ordinal

3

object named as

Sonja Meyer zu Berstenhorst

1 reference

24 August 2017

4

Jörg Pietruszka

1 reference

24 August 2017

Ulrich Krauss

2

1 reference

24 August 2017

Karl-Erich Jaeger

series ordinal

5

1 reference

24 August 2017

language of work or name

English

0 references

publication date

20 February 2011

1 reference

Applied Microbiology and Biotechnology

24 August 2017

published in

1 reference

24 August 2017

volume

90

1 reference

24 August 2017

issue

1

1 reference

24 August 2017

page(s)

23-40

1 reference

GCN4 protein, a positive transcription factor in yeast, binds general control promoters at all 5' TGACTC 3' sequences

24 August 2017

cites work

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Blue light activates the sigmaB-dependent stress response of Bacillus subtilis via YtvA.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

In vivo mutational analysis of YtvA from Bacillus subtilis: mechanism of light activation of the general stress response

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structure and mechanism of a bacterial light-regulated cyclic nucleotide phosphodiesterase

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

1.4 A structure of photoactive yellow protein, a cytosolic photoreceptor: unusual fold, active site, and chromophore

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A single flavoprotein, AppA, integrates both redox and light signals in Rhodobacter sphaeroides.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The LOV domain: a chromophore module servicing multiple photoreceptors

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A caged doxycycline analogue for photoactivated gene expression.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A blue light inducible two-component signal transduction system in the plant pathogen Pseudomonas syringae pv. tomato

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A blue light-inducible phosphodiesterase activity in the cyanobacterium Synechococcus elongatus

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Cryptochromes: blue light receptors for plants and animals

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Genome-wide analysis of light-inducible responses reveals hierarchical light signalling in Neurospora

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Physical interaction between VIVID and white collar complex regulates photoadaptation inNeurospora

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photocaged t7 RNA polymerase for the light activation of transcription and gene function in pro- and eukaryotic cells

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Identification and characterization of a cyclic di-GMP-specific phosphodiesterase and its allosteric control by GTP.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

LOV (light, oxygen, or voltage) domains of the blue-light photoreceptor phototropin (nph1): binding sites for the chromophore flavin mononucleotide.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Steric interactions stabilize the signaling state of the LOV2 domain of phototropin 1.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoexcited Structure of a Plant Photoreceptor Domain Reveals a Light-Driven Molecular Switch

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Cyclic di-GMP as a bacterial second messenger.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Principles and applications of the photochemical control of cellular processes.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Histidine kinases: diversity of domain organization

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The GCN4 basic region leucine zipper binds DNA as a dimer of uninterrupted alpha helices: crystal structure of the protein-DNA complex

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

PpsR: a multifaceted regulator of photosynthesis gene expression in purple bacteria.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A novel genetic system to detect protein-protein interactions

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Signal transduction by the EnvZ-OmpR phosphotransfer system in bacteria

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The blue-light receptor YtvA acts in the environmental stress signaling pathway of Bacillus subtilis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Genetic engineering of phytochrome biosynthesis in bacteria.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A haemoprotein with kinase activity encoded by the oxygen sensor of Rhizobium meliloti

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Bacteriophytochrome controls photosystem synthesis in anoxygenic bacteria

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Genetic evidence that PpsR from Rhodobacter sphaeroides 2.4.1 functions as a repressor of puc and bchF expression

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Molecular genetic analysis suggesting interactions between AppA and PpsR in regulation of photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

BLUF: a novel FAD-binding domain involved in sensory transduction in microorganisms

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structure of a biological oxygen sensor: a new mechanism for heme-driven signal transduction

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Mammalian synthetic biology: engineering of sophisticated gene networks

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Strategies for protein synthetic biology.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Genome-wide analyses revealing a signaling network of the RcsC-YojN-RcsB phosphorelay system in Escherichia coli

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

SigB-dependent general stress response in Bacillus subtilis and related gram-positive bacteria

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Principles of c-di-GMP signalling in bacteria

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

FHY1 and FHL act together to mediate nuclear accumulation of the phytochrome A photoreceptor.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Cyanobacteriochrome CcaS is the green light receptor that induces the expression of phycobilisome linker protein

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoactive yellow protein-based protein labeling system with turn-on fluorescence intensity

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Red and far-red light alter the transcript profile in the cyanobacterium Synechocystis sp. PCC 6803: impact of cyanobacterial phytochromes.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Phytochrome three-dimensional structures and functions

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

VIVID interacts with the WHITE COLLAR complex and FREQUENCY-interacting RNA helicase to alter light and clock responses in Neurospora

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structure and photoreaction of photoactive yellow protein, a structural prototype of the PAS domain superfamily

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A blue-light-activated adenylyl cyclase mediates photoavoidance in Euglena gracilis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Distribution and phylogeny of the blue light receptors aureochromes in eukaryotes

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

An Arabidopsis circadian clock component interacts with both CRY1 and phyB.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Light and redox control of photosynthesis gene expression in Bradyrhizobium: dual roles of two PpsR.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Studies of the Escherichia coli Trp repressor binding to its five operators and to variant operator sequences.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Rapid photolytic release of adenosine 5'-triphosphate from a protected analog: utilization by the sodium:potassium pump of human red blood cell ghosts

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photochemical properties of the flavin mononucleotide-binding domains of the phototropins from Arabidopsis, rice, and Chlamydomonas reinhardtii

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Cyclic nucleotide-gated ion channels

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

New classes of mutants in complementary chromatic adaptation provide evidence for a novel four-step phosphorelay system

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Responding to color: the regulation of complementary chromatic adaptation

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Synthetic biology: applications come of age

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

ZEITLUPE is a circadian photoreceptor stabilized by GIGANTEA in blue light.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Transcriptional regulation by cAMP and its receptor protein

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A comparison of the different DNA binding specificities of the bZip proteins C/EBP and GCN4.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Distribution and phylogeny of light-oxygen-voltage-blue-light-signaling proteins in the three kingdoms of life

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Heterologous production of Halorhodospira halophila holo-photoactive yellow protein through tandem expression of the postulated biosynthetic genes

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Surface sites for engineering allosteric control in proteins

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Illuminating the chemistry of life: design, synthesis, and applications of "caged" and related photoresponsive compounds.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

PIFs: pivotal components in a cellular signaling hub.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Synthetic biology: engineering Escherichia coli to see light

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Spatially discrete, light-driven protein expression

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Light activated recombination

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoexcited CRY2 interacts with CIB1 to regulate transcription and floral initiation in Arabidopsis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The bacterial counterparts of plant phototropins

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Flavin-based Blue-Light photosensors: a photobiophysics update

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Bacterial bilin- and flavin-binding photoreceptors.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

First evidence for phototropin-related blue-light receptors in prokaryotes

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoadaptation in Neurospora by Competitive Interaction of Activating and Inhibitory LOV Domains

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

AppA is a blue light photoreceptor that antirepresses photosynthesis gene expression in Rhodobacter sphaeroides.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Biologically active molecules with a "light switch".

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Signal integration in bacterial two-component regulatory systems.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Design and signaling mechanism of light-regulated histidine kinases

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structure and signaling mechanism of Per-ARNT-Sim domains

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Addition at the molecular level: signal integration in designed Per-ARNT-Sim receptor proteins

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A photoswitchable DNA-binding protein based on a truncated GCN4-photoactive yellow protein chimera.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structure-based design of a photocontrolled DNA binding protein.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Transcriptional regulation and function of the Neurospora clock gene white collar 2 and its isoforms

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

LapD is a bis-(3',5')-cyclic dimeric GMP-binding protein that regulates surface attachment by Pseudomonas fluorescens Pf0-1.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoactivated adenylyl cyclase controls phototaxis in the flagellate Euglena gracilis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Blue light diminishes interaction of PAS/LOV proteins, putative blue light receptors in Arabidopsis thaliana, with their interacting partners.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Transcriptome analysis of all two-component regulatory system mutants of Escherichia coli K-12.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Assembly of Cell Regulatory Systems Through Protein Interaction Domains

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoactive yellow protein: a structural prototype for the three-dimensional fold of the PAS domain superfamily.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoregulation in prokaryotes

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A photosensory two-component system regulates bacterial cell attachment

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

An analysis of the solution structure and signaling mechanism of LovK, a sensor histidine kinase integrating light and redox signals

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Purification and initial characterization of a putative blue light-regulated phosphodiesterase from Escherichia coli

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Recent advances in the photochemical control of protein function

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A brief history of phytochromes

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Natural and engineered photoactivated nucleotidyl cyclases for optogenetic applications

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Light-activated gene expression directs segregation of co-cultured cells in vitro

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

FKF1 and GIGANTEA complex formation is required for day-length measurement in Arabidopsis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Theoretical investigation of the excited states of 2-nitrobenzyl and 4,5-methylendioxy-2-nitrobenzyl caging groups.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structural and mechanistic determinants of c-di-GMP signalling

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Solution structure of the Mesorhizobium loti K1 channel cyclic nucleotide-binding domain in complex with cAMP

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoactive molecules for applications in molecular imaging and cell biology

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The phytochrome red/far-red photoreceptor superfamily

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A light-switchable gene promoter system

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A small GTPase activator protein interacts with cytoplasmic phytochromes in regulating root development

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Clock-associated genes in Arabidopsis: a family affair

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A switchable light-input, light-output system modelled and constructed in yeast

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The eubacterium Ectothiorhodospira halophila is negatively phototactic, with a wavelength dependence that fits the absorption spectrum of the photoactive yellow protein

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Light-activated DNA binding in a designed allosteric protein

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Rationally improving LOV domain-based photoswitches

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Vibration spectroscopy reveals light-induced chromophore and protein structural changes in the LOV2 domain of the plant blue-light receptor phototropin 1.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Blue-light-activated histidine kinases: two-component sensors in bacteria.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A synthetic genetic edge detection program.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

AUREOCHROME, a photoreceptor required for photomorphogenesis in stramenopiles

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

An unorthodox bacteriophytochrome from Rhodobacter sphaeroides involved in turnover of the second messenger c-di-GMP.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

RcaE is a complementary chromatic adaptation photoreceptor required for green and red light responsiveness

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The BLUF-EAL protein YcgF acts as a direct anti-repressor in a blue-light response of Escherichia coli

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photoreceptor proteins, "star actors of modern times": a review of the functional dynamics in the structure of representative members of six different photoreceptor families

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photosensing in chemotrophic, non-phototrophic bacteria: let there be light sensing too.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Expanding the genetic code

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Cross-talk between an orphan response regulator and a noncognate histidine kinase in Streptomyces coelicolor

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

The lactose repressor system: paradigms for regulation, allosteric behavior and protein folding

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Structural overview on the allosteric activation of cyclic AMP receptor protein

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Reversible photocontrol of DNA binding by a designed GCN4-bZIP protein

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Estimation of the available free energy in a LOV2-J alpha photoswitch

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Identification of ASK and clock-associated proteins as molecular partners of LKP2 (LOV kelch protein 2) in Arabidopsis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Induction of protein-protein interactions in live cells using light

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

A cyanobacterial phytochrome two-component light sensory system.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photochemical activation of protein expression in bacterial cells

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Photochemical control of biological processes

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

Mechanism-based tuning of a LOV domain photoreceptor

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS00253-011-3141-6

10.1007/S00253-011-3141-6

21 January 2018

Identifiers

DOI

1 reference

24 August 2017

1 reference