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PubMed2006

Removal of 1,3-dichloro2-propanol and 3-chloro1,2-propanediol by the whole cell system of pseudomonas putida DSM 437.

The removal of 1,3-dichloro-2-propanol (1,3-DCP), 3-chloro-1,2-propanediol (3-CPD) and their mixtures at concentrations up to 1,000 mg . L(-1) by the whole cell system of Pseudomonas putida DSM 437 was investigated. The 1,3-DCP removal rates ranged from 2.36 to 10.55 mg . L(-1) . h(-1); 3-CPD exhibited approximately two times higher removal rates compared to 1,3-DCP for all concentrations tested. Removal of 1,3-DCP and 3-CPD followed first-order kinetics with rate constants of 0.0109 h(-1) and 0.0206 h(-1), respectively. When the whole cell system of P. putida DSM 437 was applied to mixtures of the two halohdrins, complete removal of 1,3-DCP was achieved at 144 h while removal of 3-CPD was completed at times ranging from 72 to 144 h. Time to achieve 50% removal of both halohydrins depends on the initial concentration of each in the mixture. For 1,3-DCP, it ranged from 40.55 h at 200 mg . L(-1) to 53.28 h at 500 mg . L(-1) while the respected values for 3-CPD were 33.39 and 68.91 h.

Biodegradation, Environmental↗
PubMed1985

The cytoplasmic filament system in critical point-dried whole mounts and plastic-embedded sections.

High voltage electron microscopy of intact cells prepared by the critical point drying (CPD) procedure has become an important tool in the study of three-dimensional relationships between cytoplasmic organelles. It has been claimed that critical point-dried specimens reveal a structure that is not visible in sections of plastic-embedded material; it has also been claimed that this structure, in association with known cytoplasmic filaments, forms a meshwork of tapering threads ("microtrabecular lattice"). Alternatively, this structure might be a surface tension artifact produced during CPD. To test possible sources of artifacts during CPD, model fiber systems of known structure were used. It was found that traces of water or ethanol in the CO2 caused distortions and fusion of fibers in pure muscle actin, fibrin, collagen, chromatin, and microtubules that produce a structure very similar to the proposed "microtrabecular lattice." These structures were, however, well preserved if water and ethanol were totally excluded from the CO2. The same results were obtained with whole mounts of cultured cells. A "microtrabecular lattice" was obtained if some water or ethanol was present in the pressure chamber. On the other hand, when water or ethanol were totally excluded from the CO2 during CPD, cytoplasmic filaments were uniform in thickness similar to their appearance in sections of plastic-embedded cells. It is concluded that the "microtrabecular lattice" is a distorted image of the cytoplasmic filament network produced during CPD by traces of water or ethanol in the CO2.

Actins↗
PubMed2006

Sensitivity of rice to ultraviolet-B radiation.

BACKGROUND: Depletion of the stratospheric ozone layer leads to an increase in ultraviolet-B (UVB: 280-320 nm) radiation reaching the earth's surface, and the enhanced solar UVB radiation predicted by atmospheric models will result in reduction of growth and yield of crops in the future. Over the last two decades, extensive studies of the physiological, biochemical and morphological effects of UVB in plants, as well as the mechanisms of UVB resistance, have been carried out. SCOPE: In this review, we describe recent research into the mechanisms of UVB resistance in higher plants, with an emphasis on rice (Oryza sativa), one of the world's most important staple food crops. Recent studies have brought to light the following remarkable findings. UV-absorbing compounds accumulating in the epidermal cell layers have traditionally been considered to function as UV filters, and to play an important role in countering the damaging effects of UVB radiation. Although these compounds are effective in reducing cyclobutane pyrimidine dimer (CPD) induction in plants exposed to a challenge exposure to UVB, certain levels of CPD are maintained constitutively in light conditions containing UVB, regardless of the quantity or presence of visible light. These findings imply that the systems for repairing DNA damage and scavenging reactive oxygen species (ROS) are essential for plants to grow in light conditions containing UVB. CONCLUSION: CPD photolyase activity is a crucial factor determining the differences in UVB sensitivity between rice cultivars. The substitution of one or two bases in the CPD photolyase gene can alter the activity of the enzyme, and the associated resistance of the plant to UVB radiation. These findings open up the possibility, in the near future, of increasing the resistance of rice to UVB radiation, by selective breeding or bioengineering of the genes encoding CPD photolyase.

DNA, Plant↗
PubMed1988

Spatial frequency-dependent abnormalities of the pattern electroretinogram and visual evoked potentials in a parkinsonian monkey model.

The pattern visual evoked potential (PVEP) and pattern electroretinogram (PERG) were studied in 5 cynomolgus monkeys before and during the development of a parkinsonian syndrome induced by MPTP. The stimuli were vertical bars of four spatial frequencies (0.5, 1.2, 2.5 and 3.5 cycles/degree (cpd) modulated at temporal rates of 1, 4, 6, and 8 Hz. Following MPTP administration, all monkeys developed parkinsonian signs accompanied by changes in the amplitude and latency of the PVEP and PERG. Sinemet L-dopat carbi olopa administration produced temporary recovery of both PVEP and PERG. Two of the monkeys were followed for a prolonged period: 30-40 days after MPTP, the parkinsonian signs showed partial recovery; the PVEP latency and amplitude to 2.5 and 3.5 cpd stimuli and the latency to 1.2 cpd showed improvement but remained abnormal. The latencies of PERGs were normal, but the amplitudes were significantly reduced when stimuli of 2.5 and 3.5 cpd were used. Both PVEP and PERG to 0.5 cpd stimuli returned to normal. No further modifications were seen in the recordings performed 6 months and 1 year later. This study demonstrates (1) that spatial frequency-dependent electrophysiological abnormalities occur in the MPTP-treated monkey, a result previously found in human Parkinson's disease, and (2) that dopamine has a specific function in neurotransmission in the visual system of primates.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1982

Peritonitis due to a mycobacterium chelonei-like organism associated with intermittent chronic peritoneal dialysis.

Two outbreaks of peritonitis caused by a Mycobacterium chelonei-like organism--a previously unrecognized pathogen--occurred among patients receiving intermittent chronic peritoneal dialysis (CPD). In one center, five of 22 patients who had undergone CPD during a one-month period developed peritonitis caused by an M. chelonei-like organism acquired from a single contaminated automated CPD machine. In a second center, five of eight patients who had received CPD during a several-week period became infected, apparently as a result of cross-infection from contaminated machines. Seven sporadic cases of peritonitis due to an M. chelonei-like organism were also found. M. chelonei-like organisms can survive and proliferate in water and are relatively resistant to formaldehyde. Defects in the design of CPD machines and disinfection procedures were identified that may have permitted M. chelonei-like organisms to survive attempted disinfection.

Adult↗
PubMed2002

Characterization of Arabidopsis photolyase enzymes and analysis of their role in protection from ultraviolet-B radiation.

DNA photolyases are enzymes which mediate the light-dependent repair (photoreactivation) of UV-induced damage products in DNA by direct reversal of base damage rather than via excision repair pathways. Arabidopsis thaliana contains two photolyases specific for photoreactivation of either cyclobutane pyrimidine dimers (CPDs) or pyrimidine (6-4)pyrimidones (6-4PPs), the two major UV-B-induced photoproducts in DNA. Reduced FADH and a reduced pterin were identified as cofactors of the native Arabidopsis CPD photolyase protein. This is the first report of the chromophore composition of any native class II CPD photolyase protein to our knowledge. CPD photolyase protein levels vary between tissues and with leaf age and are highest in flowers and leaves of 3-5-week-old Arabidopsis plants. White light or UV-B irradiation induces CPD photolyase expression in Arabidopsis tissues. This contrasts with the 6-4PP photolyase protein which is constitutively expressed and not regulated by either white or UV-B light. Arabidopsis CPD and 6-4PP photolyase enzymes can remove UV-B-induced photoproducts from DNA in planta even when plants are grown under enhanced levels of UV-B irradiation and at elevated temperatures although the rate of removal of CPDs is slower at high growth temperatures. These studies indicate that Arabidopsis possesses the photorepair capacity to respond effectively to increased UV-B-induced DNA damage under conditions predicted to be representative of increases in UV-B irradiation levels at the Earth's surface and global warming in the twenty-first century.

Adaptation, Physiological↗
PubMed2000

DNA binding mode of the Fab fragment of a monoclonal antibody specific for cyclobutane pyrimidine dimer.

Monoclonal antibodies specific for the cyclobutane pyrimidine dimer (CPD) are widely used for detection and quantification of DNA photolesions. However, the mechanisms of antigen binding by anti-CPD antibodies are little understood. Here we report NMR analyses of antigen recognition by TDM-2, which is a mouse monoclonal antibody specific for the cis - syn -cyclobutane thymine dimer (T[ c, s ]T). (31)P NMR and surface plasmon resonance data indicated that the epitope recognized by TDM-2 comprises hexadeoxynucleotides centered on the CPD. Chemical shift perturbations observed for TDM-2 Fab upon binding to d(T[ c, s ]T) and d(TAT[ c, s ]TAT) were examined in order to identify the binding sites for these antigen analogs. It was revealed that d(T[ c, s ]T) binds to the central part of the antibody-combining site, while the CPD-flanking nucleotides bind to the positively charged area of the V(H)domain via electrostatic interactions. By applying a novel NMR method utilizing a pair of spin-labeled DNA analogs, the orientation of DNA with respect to the antigen-binding site was determined: CPD-containing oligonucleotides bind to TDM-2 in a crooked form, draping the 3'-side of the nucleotides onto the H1 and H3 segments, with the 5'-side on the H2 and L3 segments. These data provide valuable information for antibody engineering of TDM-2.

Animals↗
PubMed2003

UVA-induced cyclobutane pyrimidine dimers form predominantly at thymine-thymine dipyrimidines and correlate with the mutation spectrum in rodent cells.

Ligation-mediated PCR was employed to quantify cyclobutane pyrimidine dimer (CPD) formation at nucleotide resolution along exon 2 of the adenine phosphoribosyltransferase (aprt) locus in Chinese hamster ovary (CHO) cells following irradiation with either UVA (340-400 nm), UVB (295-320 nm), UVC (254 nm) or simulated sunlight (SSL; lambda > 295 nm). The resulting DNA damage spectrum for each wavelength region was then aligned with the corresponding mutational spectrum generated previously in the same genetic target. The DNA sequence specificities of CPD formation induced by UVC, UVB or SSL were very similar, i.e., in each case the overall relative proportion of this photoproduct forming at TT, TC, CT and CC sites was approximately 28, approximately 26, approximately 16 and approximately 30%, respectively. Furthermore, a clear correspondence was noted between the precise locations of CPD damage hotspots, and of 'UV signature' mutational hotspots consisting primarily of C-->T and CC-->TT transitions within pyrimidine runs. However, following UVA exposure, in strong contrast to the above situation for UVC, UVB or SSL, CPDs were generated much more frequently at TT sites than at TC, CT or CC sites (57% versus 18, 11 and 14%, respectively). This CPD deposition pattern correlates well with the strikingly high proportion of mutations recovered opposite TT dipyrimidines in UVA- irradiated CHO cells. Our results directly implicate the CPD as a major promutagenic DNA photoproduct induced specifically by UVA in rodent cells.

Adenine Phosphoribosyltransferase↗
PubMed2006

A prospective multicentre study of the nutritional status in children on chronic peritoneal dialysis.

The anthropometry-bioimpedance analysis-nutrition (ABN) score is a recently proposed objective method of assessing malnutrition in children on chronic peritoneal dialysis (CPD) that uses nine parameters based on anthropometry, skinfold thickness and bioimpedance analysis. The aim of this prospective, cross-sectional study was to apply it to children treated with CPD in seven Italian paediatric nephrology centres, with a score of < 10.33 (the 3rd percentile in a population of 264 healthy children) classifying the children as malnourished. The other considered parameters were age, age at the start of dialysis and duration of dialysis; serum haemoglobin, urea, creatinine, total protein, albumin, transferrin, bicarbonate and C-reactive protein; residual urine output; urinary and peritoneal creatinine clearance; and daily protein and energy intake. The study enrolled 43 patients (mean age 10.2 +/- 4.2 years), 21 of whom (48.8%) had an ABN score of < 10.33: 15 with mild, five with moderate, and one with severe malnutrition. The malnourished patients started CPD at a younger age (P < 0.05) and had a longer duration of dialysis (P < 0.01), and a significant worsening in nutritional status was observed in those treated for more than 12 months of dialysis; they also had significantly lower serum albumin, creatinine and haemoglobin levels. In conclusion, protein-calorie malnutrition is common in children receiving CPD. A younger age at the start of dialysis and a longer duration of treatment are clear risk factors, and counterbalance the long-term viability of CPD in paediatric age.

Adolescent↗
PubMed2006

Predictors of depression outcomes in medical inpatients with chronic pulmonary disease.

OBJECTIVE: Baseline patient characteristics and depression treatments were examined as predictors of speed of depression remission in hospitalized medical patients with chronic pulmonary disease (CPD). METHODS: Consecutively admitted patients over age 50 years with CPD were screened for major and minor depression using the Structured Clinical Interview for Depression. Patients with minor depression were followed up over 12-24 weeks with the Longitudinal Interview Follow-up Evaluation. Course of depression and predictors of remission were examined. RESULTS: Seven hundred eleven depressed patients with CPD (410 with minor, 301 with major depression) were identified and assessed over time. Two-thirds with minor depression had remitted by 12 weeks compared with 26.9% with major depression at 12 weeks and 49.2% at 24 weeks. Predictors of faster remission for minor depression were black race, community hospital admission, less severe depression, less medical comorbidity, less severe CPD, more social support, and no antidepressant treatment. For major depression, less severe depression, no past antidepressant drug treatment, and less intense current antidepressant treatment predicted faster remission. CONCLUSIONS: The course of depressive disorder after discharge in patients hospitalized with CPD can be predicted by characteristics during admission. Although patients with minor depression may be followed and treatment initiated only if depression persists, those with major depression need more aggressive treatment and psychiatric consultation if improvement does not occur.

Adaptation, Psychological↗
PubMedDate not supplied

Development and early testing of a simple subcutaneous counterpulsation device.

The intra-aortic balloon pump has been widely and successfully used as a treatment for cardiac dysfunction, but it only has short-term applications. To overcome this limitation, a superficial counterpulsation device (CPD) is being developed to provide extended counterpulsation support to promote myocardial recovery. The CPD is a valveless, monoport, pneumatically driven, 40-ml sac that is intended to be implanted in a pacemaker-type pocket in the subclavian fossa. The sac is designed to fill in systole and empty during diastole through an outflow graft anastomosed to the subclavian artery. A feasibility study was conducted to investigate acute hemodynamic responses to the CPD in eight calves with diminished cardiac function. The CPD augmented aortic diastolic pressure, reduced left ventricular peak systolic and aortic ejection pressures by up to 18%, and increased diastolic coronary flow by up to 21% and stroke volume by up to 12%. A cadaver fit study demonstrated that the human subclavian artery is a reasonable anastomosis site to consider and that the 40-ml CPD needs to be reduced in size to provide a better anatomical fit. The clinical attractiveness of this approach is that it may provide extended support through a subcutaneous surgical procedure.

Animals↗
PubMed1987

Dissipation of the Membrane Potential in Susceptible Corn Mitochondria by the Toxin of Helminthosporium maydis, Race T, and Toxin Analogs.

We have tested directly the effect of Helminthosporium maydis T (Hmt) toxin and various analogs on the membrane potential formed in mitochondria isolated from a Texas (T) cytoplasmic male-sterile and a normal (N) corn. ATP, malate or succinate generated a membrane potential (negative inside) as monitored by the absorbance change of a cationic dye, safranine. The relative membrane potential (Deltapsi) could also be detected indirectly as (45)Ca(2+) uptake. Hmt toxin added to T mitochondria dissipated the steady state Deltapsi similar to addition of a protonophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP). Toxin analogs (Cpd XIII: C(41)H(68)O(12) and Cpd IV: C(25)H(44)O(6)), reduced native toxin (RT2C: C(41)H(84)O(13)) and Pm toxin (band A: C(33)H(60)O(8), produced by the fungus, Phyllosticta maydis) were effective in dissipating Deltapsi and decreasing Ca(2+) uptake with the following order: Pm (100) >> HmT (23-30) > Cpd XIII (11-25) >> RT2C (0-4-1.8) > Cpd IV (0.2-1.0). In contrast, the toxins and analogs had no effect on Deltapsi formed in N mitochondria. The striking similarities of the HmT toxin (band 1: C(41)H(68)O(13)) and Cpd XIII on T mitochondrial activities provide strong evidence supporting the correctness of the polyketol structure assigned to the native toxin. Since the Deltapsi in energized mitochondria is caused mainly by the electrogenic extrusion of H(+), the results support the idea that HmT toxin increases membrane permeability of T mitochondria to H(+). The host specificity of the toxin suggests that an interaction with unique target site(s) on the inner mitochondrial membrane of T corn causes H(+) leakage.

Journal Article↗
PubMed2005

The photocarcinogenesis of antibiotic lomefloxacin and UVA radiation is enhanced in xeroderma pigmentosum group A gene-deficient mice.

Lomefloxacin (LFLX) is phototoxic and phototumorigenic, but the mechanisms of phototumorigenesis of quinolone drugs have not been fully elucidated. Formation of cyclobutane pyrimidine dimers (CPD) by UVB radiation is primarily involved in the carcinogenesis of ultraviolet (UV) radiation. On the other hand, UVA region is responsible to photobiologic reactions of quinolone drugs. To know if CPD can be formed by UVA radiation in the presence of LFLX and is involved in the phototumorigenesis, we used xeroderma pigmentosum (XP) group A gene-deficient (XPA-/-) mouse, which is defective in nucleotide excision repair. XPA-/- and XPA+/+ mice were irradiated to 5 J per cm2-UVA with or without the administration of LFLX. In XPA-/- mice treated with LFLX, the first skin tumor appeared after exposures to 75 J per cm2 in 5 wk. In XPA+/+ mice treated with LFLX, the first tumor appeared after exposures to 345 J per cm2 in 23 wk. Immunohistochemically, CPD formation was observed after UVA-exposure in the skin of XPA+/+ as well as XPA-/- mice which had been given LFLX. The CPD disappeared, however, earlier from XPA+/+ mice than from XPA-/- mice. The acute inflammatory reaction after LFLX administration and exposure to UVA were greatly enhanced in XPA-/- mice. These results indicate that UVA exposure induces DNA damage in the form of CPD in the presence of LFLX, which exerts phototoxicity and phototumorigenesis.

Animals↗
PubMed2000

Critical role of extracellular signal-regulated kinase (ERK) phosphorylation in novel vitamin K analog-induced cell death.

In the present study, we show that 2-(2-hydroxyethylsulfaryl)-3-methyl-1,4-naphthoquinone, or CPD 5, is a potent growth inhibitor for pancreas cancer cell lines (ID(50): 21.4 +/- 3.8, 31.8 +/- 2.7 and 55.2 +/- 4.5 microM for MiaPaCa, Panc-1 and BxPc3, respectively). It induced protein tyrosine phosphor-ylation of hepatocyte growth factor (HGF) receptor (c-Met) or epidermal growth factor receptor (EGFR), which increased progressively to a maximum level at 30 min in Panc-1 cells. The receptor phosphorylation by CPD 5 was indicated to be functional, since these receptors were found to bind with Grb2 or SOS1 protein. CPD 5 was also suggested to induce phosphorylation of external signal-regulated kinase (ERK). EGF induced cell proliferation through ERK phosphorylation, since U0126, which is an inhibitor of ERK phosphorylation, abrogated the increase of cyclin D1 by EGF. HGF increased the amount of p27 protein, suggesting that it is associated with cell differentiation. By contrast, U0126 reduced CPD 5-induced cell death. On two-dimensional electrophoresis, we found an extra type of phospho-ERK, and this was completely and selectively abolished by U0126. These results suggest that ERK phosphorylation, especially the extra spot on two-dimensional gel, is critically associated with CPD 5-mediated cell death.

Antineoplastic Agents↗
PubMed2005

Spontaneously occurring mutations in the cyclobutane pyrimidine dimer photolyase gene cause different sensitivities to ultraviolet-B in rice.

Sensitivity to ultraviolet-B (UVB) radiation (280-320 nm) varies widely among rice cultivars. We previously indicated that UV-resistant rice cultivars are better able to repair cyclobutane pyrimidine dimers (CPDs) through photorepair than are UV-sensitive cultivars. In this paper, we report that UVB sensitivity in rice, in part, is the result of defective CPD photolyase alleles. Surjamkhi (indica) exhibited greater sensitivity to UVB radiation and was more deficient in CPD photorepair ability compared with UV-resistant Sasanishiki (japonica). The deficiency in CPD photorepair in Surjamkhi resulted from changes in two nucleotides at positions 377 and 888 in the photolyase gene, causing alterations of two deduced amino acids at positions 126 and 296 in the photolyase enzyme. A linkage analysis in populations derived from Surjamkhi and Sasanishiki showed that UVB sensitivity is a quantitative inherited trait and that the CPD photolyase locus is tightly linked with a quantitative trait locus that explains a major portion of the genetic variation for this trait. These results suggest that spontaneously occurring mutations in the CPD photolyase gene cause different degrees of sensitivity to UVB in rice, and that the resistance of rice to UVB radiation could be increased by increasing the photolyase function through conventional breeding or bioengineering.

Amino Acid Sequence↗
PubMed1981

Accumulative effect of DDAVP and heparin in increasing plasma factor VIII levels.

DDAVP (l-desaminocysteine-(8-D-arginine)-vasopressin) produces a marked increase in plasma factor VIII procoagulant (F VIII:C) levels. Previously, we have reported that blood collected into heparin rather than into CPD anticoagulant results in higher starting levels of plasma F VIII:C activity. We therefore wished to determine whether the effects of these two agents were accumulative and whether they would result in any difference in the relative molecular distribution of F VIII:C. Blood was collected into CPD or heparin immediately before and 15 min after an intravenous dose of 0.2 micrograms/kg body weight of DDAVP. Pre-stimulation factor VIII levels were approximately 36% higher in heparinized plasma than in CPD plasma. Following DDAVP stimulation, the final factor VIII activity was increased 3.9-fold when either of the anticoagulants was used, with the heparin sample maintaining a 37% increase over the CPD sample. Column chromatography on Sepharose CL-6B of pre- and post-DDAVP plasma samples collected into either heparin or CPD indicated that there was no change in the relative distribution of the high and low molecular weight forms of F VIII:C. The heparinized sample showed the typical distribution of approximately 60% F VIII:C at void volume (Vo) and 40% at 2.3 Vo, suggesting that DDAVP-stimulated increases of plasma F VIII:C are equally distributed between the carrier and non-carrier associated F VIII:C activities.

Arginine Vasopressin↗
PubMed1986

Preservation of red blood cells: content of microaggregates and di-2-ethylhexylphthalate (DEHP) in red blood cells stored in saline-adenine-glucose-mannitol (SAGM) medium.

The content of microaggregates was determined in leukocyte-poor red blood cells (RBC) after 5 weeks of storage in citrate-phosphate-dextrose (CPD)-adenine plasma and in saline-adenine-glucose-mannitol (SAGM) medium. The size range was 3,600-200,000 fl, corresponding to a particle diameter of 19-73 micron, presuming a spherical particle shape. In comparison with CPD-adenine whole blood (100%), the total number of particles per unit of RBC was found to be 41.2% (CPD-adenine anticoagulant) and 25.4% (SAGM medium). The corresponding data for total particle volumes were 43.3 and 30.3%. The significant differences between the two categories of RBC could not be explained on the basis of differences concerning pH or cell composition. A majority of particles (50-62%) was observed in the lowest size range (19-29 microns), corresponding to only 18-26% of the total particle volume. The accumulation of di-2-ethylhexylphthalate (DEHP) was determined in two variations of RBC stored in SAGM medium and in RBC stored in CPD-adenine plasma. The quantities of DEHP per unit of RBC after 5 weeks were significantly smaller in SAGM medium (9.0 +/- 3.6 and 22.7 +/- 6.1 mg, respectively) compared to CPD-adenine plasma (30.1 +/- 9.5 mg).

Adenine↗
PubMed2005

Purification, cDNA cloning, and expression profiles of the cyclobutane pyrimidine dimer photolyase of Xenopus laevis.

Photolyase is a light-dependent enzyme that repairs pyrimidine dimers in DNA. Two types of photolyases have been found in frog Xenopus laevis, one for repairing cyclobutane pyrimidine dimers (CPD photolyase) and the other for pyrimidine-pyrimidone (6-4)photoproduct [(6-4)photolyase]. However, little is known about the former type of the Xenopus photolyases. To characterize this enzyme and its expression profiles, we isolated the entire coding region of a putative CPD photolyase cDNA by extending an EST (expressed sequence tag) sequence obtained from the Xenopus database. Nucleotide sequence analysis of the cDNA revealed a protein of 557 amino acids with close similarity to CPD photolyase of rat kangaroo. The identity of this cDNA was further established by the molecular mass (65 kDa) and the partial amino acid sequences of the major CPD photolyase that we purified from Xenopus ovaries. The gene of this enzyme is expressed in various tissues of Xenopus. Even internal organs like heart express relatively high levels of mRNA. A much smaller amount was found in skin, although UV damage is thought to occur most frequently in this tissue. Such expression profiles suggest that CPD photolyase may have roles in addition to the photorepair function.

Amino Acid Sequence↗