[A preliminary comparison on ophthalmic examination indices of workers with different occupations in Shenzhen].

Objective: To compare the ophthalmic examination indices of different occupational groups in Shenzhen and analyze the possible health problems, so as to provide research basis for further health intervention. Methods: In March 2021, 5426 professionals with ophthalmic examination index data were selected from the basic health database of "Shenzhen occupational population protection action". Among them, radiation workers (694), port operators (1756), sanitation workers (946), teachers (224), video workers (154), police (927) and firefighters (100) were selected as the investigated occupational population. They were exposed to noise 625 workers with traditional occupational hazards such as noise, chemical poisons and dust were used as the control population.Ophthalmic examination indices included right eye vision, left eye vision, outer eye, conjunctiva, cornea, lens, and fundus oculi. The differences of each index in different occupational groups were compared. Results: Compared with the control group, the port operator group showed lower abnormal rates of binocular vision and fundus oculi (P<0.05), but higher abnormal rates of conjunctiva (P=0.029), the environmental sanitation worker group showed higher abnormal rates of binocular vision and conjunctiva (all P<0.01), the teacher group had higher abnormal rates of binocular vision, but only the difference of left eye vision was statistically significant (P=0.021), and the video worker group had higher abnormal rates of right and left eyes vision (P=0.029、0.006) . Conclusion: There were some degrees of ophthalmic problems in different occupational population, therefore targeted intervention measures should be taken according to the characteristics of each group.

[Analysis of volatile organic components of organic solvents used in Bao'an District of Shenzhen].

Objective: To understand the volatile organic components in the organic solvents used by enterprises in Baoan District, Shenzhen. Methods: From January to December 2020, a total of 541 organic solvent samples used by 86 companies were collected for volatile organic component analysis, and the main volatile components and high-risk occupational hazards in organic solvents used in different industries were analyzed. Results: A total of 201 volatile organic components were detected in 541 organic solvents. The top 5 components detected include xylene (29.76%, 116/541), toluene (21.81%, 118/541), methanol (20.70%, 112/541), n-hexane (14.79%, 80/541) and ethylbenzene (14.23%, 77/541). The detection rates of benzene, trichloroethylene, n-hexane, and 1, 2-dichloroethane, which were high-risk occupational hazards, were 2.40% (13/541), 3.70% (20/541), 14.79% (80/541), and 1.66% (9/541), respectively. The volatile components in organic solvents used in different industries was different. Benzene is more frequently detected in organic solvents used in the printing industry, trichloroethylene was more frequently detected in organic solvents used in the electronics industry, and n-hexane was more commonly found in organic solvents used in the electronics industry, printing and other industries, and 1, 2-dichloroethane has been more frequently detected in organic solvents used in the machinery industry. Conclusion: There are many types of organic solvents used by enterprises in Bao'an District, with complex components and differences in different industries.

[A survey of cervical and lumbar spine diseases of express delivery employees].

Objective: To understand the current situation and influencing factors of cervical and lumbar spine diseases of the express delivery employees, and provide scientific basis for carrying out their occupational health protection in a targeted manner. Methods: From February 2020 to January 2021, the current situation research method was used to obtain 527 express delivery employees by cluster sampling. Online questionnaires were used to investigate sociodemographic characteristics and emotional characteristics, and clinical data were obtained by digital X-ray (DR) examination of the neck and waist. Pearson χ(2) test and multivariate logistic regression were used to analyze the influencing factors of cervical and lumbar spine diseases in express delivery employees. Results: The prevalence rates of cervical spine and lumbar spine diseases among express delivery employees were 49.15% (259/527) and 67.74% (357/527) , respectively. Univariate analysis showed that there were statistically significant differences in the distribution of cervical and lumbar spine disease among express delivery employees with different ages, length of service, working hours per week, and different degrees of distress due to emotional factors (P<0.05) . Multivariate analysis showed that express delivery employees aged ≥25 years old had a higher risk of cervical spine disease (P<0.05) , the express delivery employees who worked 49-55 hours per week had a lower risk of cervical spine disease (P<0.05) . Express delivery employees aged≥35 years old had a lower risk of lumbar spine disease (P<0.05) , and the risk of lumbar spine disease was higher among express delivery workers who suffered moderate or more distress due to emotional factors (such as anxiety, depression, or irritability) in the past 4 weeks (P<0.05) . Conclusion: The prevalence of cervical and lumbar spine diseases is relatively high among express delivery employees. It is recommended to adjust the weekly working hours of express delivery employees, organize psychological counseling training, and effectively protect the occupational health rights of express delivery employees.

[Investigation on occupational injury of sanitation workers in Shenzhen City].

Objective: To understand the occurrence of occupational injuries among sanitation workers in Shenzhen, and provide a scientific basis for the prevention of occupational injuries among sanitation workers. Methods: From May to November 2020, a cluster sampling method was used to select some street sanitation workers in Shenzhen to conduct a questionnaire survey. A total of 2200 questionnaires were recovered, of which 2167 were valid (98.5% effective recovery rate) . The socio-demographic data, length of service, type of work and occurrence of occupational injuries of sanitation workers were collected, and the distribution characteristics of occupational injuries and their relationship with factors such as type of work were analyzed. Results: Among the 2167 sanitation workers, 240 (11.1%) had experienced occupational injuries. The most common occupational injuries among sanitation workers were sharp injury, heat stroke and motor vehicle traffic accident, with the incidence rates of 6.1% (133/2167) , 2.4% (53/2167) and 1.7% (36/2167) respectively. There were statistically significant differences in the distribution of occupational injuries among sanitation workers with different lengths of work and types of work (P<0.05) . The incidence of occupational injury among sanitation workers with more than 5 years of service was significantly higher than that of workers with less than 5 years of service (P<0.05) . The incidence of sharp injury among garbage sorting and transportation personnel was higher (7.9%, 21/265) , the incidence of heat stroke among manual cleaners was higher (3.1%, 42/1366) , and the incidence of motor vehicle traffic accident among mechanized cleaners was higher (5.4%, 10/184) . Conclusion: There are many cases of occupational injuries among sanitation workers in Shenzhen. Targeted measures should be taken to prevent the occurrence of different types of work and different types of occupational injuries, and to improve the occupational health level of sanitation workers.

Data-driven machine-learning analysis of potential embolic sources in embolic stroke of undetermined source.

BACKGROUND AND PURPOSE: Hierarchical clustering, a common 'unsupervised' machine-learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data-driven machine-learning method, and explored variation in stroke recurrence between clusters. METHODS: We used a hierarchical k-means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum-variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer. RESULTS: Among 800 consecutive ESUS patients (43.3% women, median age 67 years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64-4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43-3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster. CONCLUSIONS: This data-driven machine-learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease.

Reduced risk of new onset stroke after kidney transplantation in Asian dialysis patients: a propensity score-matched, competing risk study in Taiwan.

BACKGROUND: Kidney transplantation (KT) has been found to reduce cardiovascular events and mortality in chronic dialysis patients. There is little data, however, regarding the risk reduction of cerebrovascular events after KT in Asian populations. This study evaluates the risk of cerebrovascular events after KT in Taiwan. METHODS: Tapping Taiwan's National Health Insurance claims data of patients with a diagnosis of end-stage renal disease (ESRD), we enrolled all KT recipients from 1999 to 2011 (n = 2908). For each KT patient, four controls (patients also diagnosed with ESRD) without KT were propensity matched by birth date, sex, selected comorbidities and duration of dialysis. All subjects were followed to the end of 2011. RESULTS: The incidence rate for stroke in the KT recipients and comparison group were 52.63 and 137.26 per 10 000 person-years, respectively. After adjustment for age, gender and comorbidities with competing mortality, KT recipients had 60% reduction in all kinds of stroke, compared to those who did not receive procedure. They were found to have a 48 and 74% reduction in ischemic and hemorrhagic stroke risk, respectively. Subgroup analyses also showed similar trends in the improvement of stroke after KT. While elderly patients, men, and those with diabetes, hypertension and coronary artery disease are at increased risk for stroke, our log-rank test revealed those that received KT had significantly lower cumulative incidence rates of stroke than those that did not (P < 0.001). CONCLUSIONS: KT was associated with reduced risk of new onset stroke in chronic dialysis patients in Taiwan.

Long-term risk of stroke in type 2 diabetes patients with diabetic ketoacidosis: A population-based, propensity score-matched, longitudinal follow-up study.

AIM: To investigate the long-term risk of stroke in type 2 diabetes (T2D) patients with previous episodes of diabetic ketoacidosis (DKA). METHODS: This retrospective nationwide population-based cohort study was conducted using Taiwan's National Health Insurance database. Claims data from 2000 to 2002 were extracted for 3572 T2D patients with DKA and 7144 controls matched for age, gender, diabetes complications severity index, frequency of clinical visits and baseline comorbidities. Patients with type 1 diabetes (T1D), identified by glucagon C-peptide stimulation or glutamic acid decarboxylase (GAD) antibody blood tests and possession of a catastrophic illness certificate were excluded. All patients were tracked until a new stroke diagnosis, death or the end of 2011. RESULTS: Of the 3572 selected patients, 270 with DKA and 404 of the 7144 controls were diagnosed with a new stroke, giving an incidence rate ratio (IRR) of 1.56 (95% CI: 1.34-1.82; P<0.0001). DKA patients had a higher risk of ischaemic stroke than those without DKA (IRR: 1.62, 95% CI: 1.34-1.96; P<0.0001), and DKA patients with hypertension and hyperlipidaemia were at even greater risk of stroke. Also, DKA patients were at particular risk for stroke during the first half-year following DKA diagnosis. After adjusting for patient characteristics and comorbidities, these patients were 1.55 times more likely to have a stroke than those without DKA (95% CI: 1.332-1.813, P<0.0001). CONCLUSION: T2D patients with previous DKA have a higher risk of stroke, especially ischaemic strokes.

Increased risk of sudden sensorineural hearing loss in patients with depressive disorders: population-based cohort study.

OBJECTIVES: To evaluate the incidence rates and risk of sudden sensorineural hearing loss among patients with depressive disorders. METHOD: Data for 27 547 patients with newly diagnosed depressive disorders and 27 547 subjects without depressive disorders between 2001 and 2008 were yielded from the Taiwan National Health Insurance Research Database. Sudden sensorineural hearing loss incidence at the end of 2011 was determined. Cumulative incidence and adjusted hazard ratio were computed. RESULTS: Sudden sensorineural hearing loss incidence was 1.45 times higher in the depressive disorders group compared to the non-depressive disorders group (p = 0.0041), with an adjusted hazard ratio of 1.460. A significant increased risk of developing sudden sensorineural hearing loss was noted in patients with diabetes mellitus, chronic kidney disease and hyperlipidaemia (p < 0.05). CONCLUSION: The results suggest an increased risk of developing sudden sensorineural hearing loss in patients with depressive disorders. Co-morbidities such as diabetes mellitus, chronic kidney disease and hyperlipidaemia significantly aggravated the risk. Depressive disorders might be considered a risk factor for sudden sensorineural hearing loss. It remains to be seen whether control of depressive disorders can decrease the incidence of sudden sensorineural hearing loss in patients with depressive disorders.

The lumazine protein-encoding gene in Photobacterium leiognathi is linked to the lux operon.

The nucleotide (nt) sequence of the lumP (EMBL accession No. X65612) gene of Photobacterium leiognathi PL741 was determined and the amino acid (aa) sequence deduced. The encoded aa sequence of lumP was identified as that of the lumazine protein (LumP) by homology with that of Photobacterium phosphoreum (56%). This small protein has a calculated M(r) of 19,997 and comprises 186 aa residues. Biochemical studies suggested that LumP is the protein which, when combined with luciferase, is responsible for the bioluminescent spectrum shift from blue-green light (490-505 nm) to blue (470 nm) in P. leiognathi. The nt sequence of the flanking region showed that lumP is linked to the lux operon but runs in the opposite direction. The gene order of the lumP and lux operon is as follows: <--lumP-R&R-luxC-luxD-luxA-luxB-luxN-lu xE-->; the R&R regulatory region sequence included two promoter systems, PR for the lux operon and PL for the lumP or the lum operon.

Sequence of the luxD gene encoding acyltransferase of the lux operon from Photobacterium leiognathi.

The nucleotide sequence of luxD (EMBL accession No. X65611), encoding acyltransferase (ACT), of the lux operon from Photobacterium leiognathi PL741 was determined, and the amino acid (aa) sequence was deduced. ACT is a component of the fatty acid reductase complex, which is responsible for converting fatty acid to aldehyde that serves as the substrate in the luciferase-catalyzed bioluminescent reactions. The protein has a calculated M(r) of 34,384 and comprises 305 aa residues. Alignment and comparison of the ACT of P. leiognathi with that of Vibrio fischeri ATCC7744, V. harveyi B392 and Xenorhabdus luminescens Hm shows that there is 66%, 59% and 61% aa identity, respectively.

Sugar interaction with metal ions. Crystal structure and FT-IR spectroscopic study of strontium galactarate mono-hydrate.

The crystal structure of strontium galactarate mono-hydrate, Sr2+ x C6H8O8(2-) x H2O, Mr = 313.76, monoclinic, P2(1)/c, a = 10.268(2), b = 10.333(2), c = 10.194(2) A, beta = 117.87(3) degrees, lambda(Mo K alpha) = 0.71073 A, Z = 4, Dx = 2.180 Mg m(-3), V = 956.1(3) A3, mu = 5.676 mm(-1), F(000) = 624, T = 293(2) K, R = 0.0260 for 1690 observed reflections and 145 parameters refined, has been determined. The galactarate ion is centro-symmetrical in the crystal structure, although it contains independent half-ions. The Sr2+ ion is nine-coordinated (tricapped trigonal prism) with five Sr-O bonds from carboxylic groups, and four from hydroxyl groups. The water molecule does not take part in the coordination. Six hydrogen bonds are formed, three of them related to the water molecule. The spectroscopic evidence shows that the carboxylic acid dimers of the free acid dissociate. The asymmetric stretching vibrations of the anionic COO groups in the salt are observed at 1609 and 1548, and 1581 cm(-1), assigned to a mono-dentate and a tetra-dentate coordination, respectively. The symmetric stretching vibration is located at 1397 cm(-1). The hydroxyl groups of the galactarate skeleton take part in the metal-oxygen interaction, and the hydrogen-bonding network is rearranged upon sugar metalation.

Sugar interaction with metal ions. FT-IR study on the structure of crystalline galactaric acid and its K+, NH4+, Ca2+, Ba2+, and La3+ complexes.

The FT-IR spectra of galactaric acid and its K+, NH4+, Ca2+, Ba2+, and La3+ salts have been recorded and interpreted. Spectroscopic evidence shows that the dimeric carboxylic groups of the free acid are dissociated upon formation of the salt, and the asymmetric and symmetric stretching vibrations of the anionic COO- group in these salts are observed at about 1600 and 1400 cm-1, respectively. The two carboxylic groups of the galactarate coordinate with Ca2+ ions in a monodentate form. One of the carboxylic groups in the Ba2+ salt coordinates in a monodentate state; another group interacts with three cations in a tetradentate form. In the K+, NH4+, and La3+ salts, the COO- groups coordinate in a polydentate manner with the cations. By comparison of the spectra of the salts with that of the free acid, it is concluded that the hydroxyl groups of the galactarate skeleton take part in metal-oxygen interaction, and the hydrogen-bonding network is rearranged upon sugar metalation. The degree of participation of the sugar OH groups in metal-galactarate interaction is varied from the K+ and NH4+ salts to the Ca2+, Ba2+, and La3+ salts.

IS element ISXC6 of Xanthomonas campestris pv. campestris.

An insertion sequence element, ISXC6, was isolated from Xanthomonas campestris pv. campestris 17 (Xc17). Sequence analysis showed that it is 1,500 bp long and has 20-bp perfect inverted repeat ends. Upon transposition, a direct repeat TAATTC was generated, flanking this IS. No significant homology was observed between this sequence and other sequences in database. Results of Southern hybridization showed that multiple copies of ISXC6 were present in 7 strains of Xanthomonas examined.

The interaction of Cu2 + ions and NaDC micelles.

By mixing an aqueous solution of CuCl2 with an NaDC aqueous solution of various concentration and initial molar ratio, seven coordinated samples with distinct appearances and characters were obtained. Their structures and components were investigated by FT-IR spectroscopy, EXAFS (the extended X-ray absorption fine structure), thermal analysis, X-ray diffraction, laser light scattering, TEM (transmission electron micrograph), element analysis and ICP (inductively coupled plasma) analysis. The following conclusions were given: (1) The complexes of Cu2+-NaDC with distinct appearances and properties were synthesized. (2) After Cu(DC)2 dissolved in NaDC aqueous solution, larger micelles (30-90 nm diameter) formed in the supernate, it is a mixed micelle with Cu(DC)2 and NaDC. So these micelles are a new kind of micelle containing two kinds of metal ions. This is a new result using metal ions as bridges to form micelle. (3) According to the different concentration of Cu2+ to NaDC, the complexes formed as gel or poly-crystals. Both the composition of gel complexes and the coordination structure of carboxyl groups with metal ions varied with the initial molar ratio of Cu2+ to Na+. The gel complexes exhibits the non-stoichiometric character. (4) These results are in agreement with physiological condition. All the different states such as gel, precipitate, micelles of various structures are present in bile of gallbladder. We can suggest an ideal model of the interaction between Cu2+ and bile salts in vivo.

[Synthesis and spectroscopic properties of rare earth complexes with o-phthalate and 1,10-phenanthroline].

The complexes of rare earth ions (Nd3+, Sm3+) with o-phthalate and 1,10-phenanthroline have been synthesized and characterized by elemental analysis, 1H NMR, IR, and DTA-TG. The compositions of complexes have been confirmed to be RE2L3.2H2O and RE2L3 phen.2H2O (RE: rare earth ions, L: o-phthalic, phen: 1,10-phenanthroline), their far-IR and FT-Raman spectra have been discussed and studied.

Increased risk of pulmonary tuberculosis in patients with previous non-tuberculous mycobacterial disease.

OBJECTIVE: To investigate whether or not there is an increased risk of pulmonary tuberculosis (PTB) after non-tuberculous mycobacterial (NTM) disease. DESIGN: A retrospective cohort study of 212 NTM patients and 4240 control cases. RESULTS: Patients with previous NTM disease had a significantly higher incidence of PTB than controls (incidence rate ratio [IRR] 14.74, 95%CI 8.71-24.94, P < 0.0001). Cox's proportional hazards analysis yielded an adjusted hazards ratio (aHR) of 10.15 (95%CI 5.67-18.17, P < 0.05) for NTM-associated PTB. The majority of the PTB cases (17/23, 73.9%) were diagnosed within 6 months after the diagnosis of NTM disease. Older age (≥65 years, aHR 4.45, 95%CI 1.94-10.22, P < 0.05), male sex (aHR 1.75, 95%CI 1.01-3.13, P < 0.05), human immunodeficiency virus (HIV) infection (aHR 12.49, 95%CI 3.20-48.79, P < 0.05) and chronic obstructive pulmonary disease (aHR 4.46, 95%CI 2.19-9.10, P < 0.05) were independent risk factors for developing PTB after NTM disease. The cumulative incidence of PTB in patients with previous NTM disease was significantly higher than in controls (P < 0.0001, Kaplan-Meier analysis). However, there was no significant difference in the survival rates in the two cohorts. CONCLUSION: Increased PTB prevalence after NTM disease was demonstrated. HIV infection was the greatest independent risk factor for subsequent development of PTB.

Hyperthyroidism and thyroid cancer risk: a population-based cohort study.

AIM: Thyroid hormones regulate the rate of metabolism and affect the differentiation and growth of many tissues in the body. We investigated the association between hyperthyroidism and cancer risk in Taiwan. PATIENTS AND METHODS: A random sample of 1 000 000 individuals from Taiwan's National Health Insurance database was enrolled. We found 17 033 patients to have newly diagnosed hyperthyroidism between 2000 and 2005. These patients were recruited along with a match cohort of 34 066 patients without hyperthyroidism. Starting from index date, we followed up all patients for 4 years to identify those who developed cancer. RESULTS: During the 4-year follow-up study, cancer was diagnosed in 1.23% of patients with hyperthyroidism and 1.02% of the member of the comparison cohort. Regression analysis showed that patients with hyperthyroidism were at greater risk of cancer incidence, especially thyroid cancer, compared the comparison cohort (HR: 1.213; 95% CI: 1.022-1.440; p<0.05 and HR: 7.355; 95% CI: 3.885-13.92; p<0.05, respectively). After adjusting for age, gender, diabetes mellitus, hypertension, hyperlipidemia, gout, geographic region, and income, patients with hyperthyroidism remained at increased risk of cancer incidence and thyroid cancer (Adjusted HR: 1.206; 95% CI: 1.015-1.433 and 6.803; 95% CI: 3.584-12.91, respectively) (both p<0.05). The longer the duration of hyperthyroidism, the greater the risk of thyroid cancer. CONCLUSIONS: This 4-year follow up study suggests that patients with hyperthyroidism are at increased risk of cancer, especially thyroid cancer.

Extrapulmonary tuberculosis: a study comparing diabetic and nondiabetic patients.

PURPOSE: The previous studies of extrapulmonary tuberculosis (EPTB) have not focused on the impacts of diabetes mellitus. We conducted a retrospective study to explore the difference between EPTB patients with and without diabetes. METHODS: The EPTB patients receiving initial treatments from Taipei Medical University Hospital between January 2003 and March 2008 were recruited. They were divided into with-diabetes (WD) group or non-diabetes (ND) group according to coexistence of diabetes mellitus or not, respectively. All characteristics of these two groups were compared. RESULTS: Seventy-five patients were enrolled into our study. Fifteen patients and 60 patients were recruited into WD and ND groups, respectively. The basic characteristics and tuberculosis sites of the two groups were compared. The prevalence of hypertension (66.7% vs. 38.3%, p=0.048) and chronic liver diseases (33.3% vs. 3.3%, p=0.003) in WD group were higher than in ND group. The incidence of tuberculous peritonitis in WD group was higher than in ND group (26.7% vs. 6.7%, p=0.046). The odds ratio of tuberculous peritonitis for WD group was 5 091 (95% CI 1.103-23.493, p=0.037). The random glucose level (10.9+/-5.8 vs. 6.8+/-1.6 mmol/L, p=0.025), the fasting glucose level (8.6+/-4.4 vs. 5.6+/-0.9 mmol/L, p=0.038), and the hemoglobin A1c level (7.4+/-1.1 vs. 5.6+/-0.4%, p=0.037) were higher in WD group than in ND group. The total bilirubin level was higher in WD group than in ND group (18.4+/-6.2 vs. 13+/-7.2 micromol/L, p=0.042). Presenting symptoms and other laboratory data were not different statistically between these two groups. CONCLUSIONS: This is the first study about the impacts of diabetes on EPTB. The prevalence of hypertension and chronic liver diseases, the incidence of tuberculous peritonitis, and the total bilirubin level were higher in EPTB patients with diabetes than those without diabetes.

Nucleotide sequence of the luxC gene encoding fatty acid reductase of the lux operon from Photobacterium leiognathi.

The nucleotide sequence of the luxC gene (EMBL Accession No. 65156) encoding fatty acid reductase (FAR) of the lux operon from Photobacterium leiognathi PL741 was determined and the encoded amino acid sequence deduced. The fatty acid reductase is a component of the fatty acid reductase complex. The complex is responsible for converting fatty acid to aldehyde which serves as the substrate in the luciferase-catalyzed bioluminescent reaction. The protein comprises 478 amino acid residues and has a calculated M(r) of 53,858. Alignment and comparison of the fatty acid reductase of P. leiognathi with that of Vibrio harveyi B392 and Vibrio fischeri ATCC 7744 shows that there is 70% and 59% amino acid residues identity, respectively.

Nucleotide sequence and functional analysis of regulatory region of the lumP and the lux operon from Photobacterium leiognathi.

The lumP gene is linked to the lux operon, but runs in the opposite direction in Photobacterium leiognathi PL741. The gene order of the lumP and the lux operon is < -lumP-R & R-luxC-luxD-luxA-luxB-luxN-luxE- > (R & R: regulatory region). The nucleotide sequence of the regulatory region (827-bp) between the lumP and the lux operon was determined. Sequence analysis illustrates that the regulatory region includes two divergent promoter systems, PR-promoter system for the lux operon (R-operon) and PL-promoter system for the lumP or lum operon (L-operon). Functional analysis of the regulatory region shows that the PR- and PL-promoter systems both are able to lead the gene expression. The deletion experiment result elicits that the PR- and PL-promoter are coordinatively and negatively regulated; the PR- and PL-promoter might be competing for recognition by RNA polymerase to initiate transcription. The fact of the LumP responsible for the spectral blue shift in P. leiognathi implied that the lumP gene closedly linked to the lux operon is for coordinative regulation with the lux operon. In addition, the glucose repression on the PR-promoter system shows that the expression of the lux operon is regulated by cAMP-CRP induction in E. coli.