Degradation of phenanthrene by different bacteria: evidence for novel transformation sequences involving the formation of 1-naphthol

Four polycyclic aromatic hydrocarbon (PAH)-degrading bacteria, namely Arthrobacter sulphureus RKJ4, Acidovorax delafieldii P4-1, Brevibacterium sp. HL4 and Pseudomonas sp. DLC-P11, capable of utilizing phenanthrene as the sole source of carbon and energy, were tested for its degradation using radiolabelled phenanthrene. [9-14C]Phenanthrene was incubated with microorganisms containing 100 mg/l unlabelled phenanthrene and the evolution of 14CO2 was monitored: within 18 h of incubation, 30.1, 35.6, 26.5 and 2.1% of the recovered radiolabelled carbon was degraded to 14CO2 by RKJ4, P4-1, HL4 and DLC-P11, respectively. When mixtures of other PAHs such as fluorene, fluoranthene and pyrene, in addition to phenanthrene, were added as additional carbon sources, there was a 36.1 and 20.6% increase in 14CO2 production from [9-14C]phenanthrene in the cases of RKJ4 and HL4, respectively, whereas P4-1 and DLC-P11 did not show any enhancement in 14CO2 production. Although, a combination of many bacteria enhances the degradation of organic compounds, no enhancement in the degradation of [9-14C]phenanthrene was observed in mixed culture involving all four microorganisms together. However, when different PAHs, as indicated above, were used in mixed culture, there was a 68.2% increase in 14CO2 production. In another experiment, the overall growth rate of P4-1 on phenanthrene could be enhanced by adding the non-ionic surfactant Triton X-100, whereas RKJ4, HL4 and DLC-P11 did not show any enhancement in growth. Pathways for phenanthrene degradation were also analysed by thin-layer chromatography, gas chromatography and gas chromatography-mass spectrometry. Common intermediates such as o-phthalic acid and protocatechuic acid were detected in the case of RKJ4 and o-phthalic acid was detected in the case of P4-1. A new intermediate, 1-naphthol, was detected in the cases of HL4 and DLC-P11. HL4 degrades phenanthrene via 1-hydroxy-2-naphthoic acid, 1-naphthol and salicylic acid, whereas DLC-P11 degrades phenanthrene via the formation of 1-hydroxy-2-naphthoic acid, 1-naphthol and o-phthalic acid. Both transformation sequences are novel and have not been previously reported in the literature. Mega plasmids were found to be present in RKJ4, HL4 and DLC-P11, but their involvement in phenanthrene degradation could not be established.

Chemotaxis of a Ralstonia sp. SJ98 toward different nitroaromatic compounds and their degradation

A Ralstonia sp. SJ98, isolated by a chemotactic enrichment technique, was capable of utilizing different nitroaromatic compounds (NACs). It utilized p-nitrophenol, 4-nitrocatechol, o-nitrobenzoic acid, and p-nitrobenzoic acid as the sole source of carbon and energy. It was observed that Ralstonia sp. SJ98 was chemotactic to the above-mentioned NACs as tested by the drop assay, swarm plate assay, and capillary assay. However, it failed to show chemotactic behavior toward those compounds which were not degraded by the microorganism. This is the first report which shows the chemotaxis of a microorganism toward different NACs and their subsequent degradation. Some of the intermediates of the NACs' degradative pathways have been identified using TLC, GC, and GC-MS studies. The results presented here indicate a correlation between chemotaxis and biodegradation of NACs.

Kinetics of biodegradation of p-nitrophenol by different bacteria

Three bacterial species, i.e., Ralstonia sp. SJ98, Arthrobacter protophormiae RKJ100, and Burkholderia cepacia RKJ200, have been examined for their efficiency and kinetics behavior toward PNP degradation. All the three bacteria utilized PNP as the sole source of carbon, nitrogen, and energy. The rates of radiolabeled [U-(14)C]PNP degradation by all the bacteria were higher in the nitrogen-free medium compared to the medium with nitrogen. The apparent K(m) values of PNP degradation by SJ98, RKJ100, and RKJ200 were 0.32, 0.28, and 0.23 mM, respectively, as determined from the Michaelis-Menten curves. The maximum rates of PNP degradation (V(max)) according to Lineweaver-Burk's plots were 11.76, 7.81, and 3.84 micromol PNP degraded/min/mg dry biomass, respectively. The interpretation drawn from the Lineweaver-Burk's plots showed that the PNP degradation by SJ98 was stimulated by 4-nitrocatechol and 1, 2,4-benzenetriol. Benzoquinone and hydroquinone inhibited PNP degradation by RKJ100 noncompetitively and competitively, respectively, whereas in the case of RKJ200, benzoquinone and hydroquinone inhibited PNP degradation in an uncompetitive manner. beta-Ketoadipate did not affect the rate of PNP degradation in any case.

Chemotaxis and biodegradation of 3-methyl- 4-nitrophenol by Ralstonia sp. SJ98

3-Methyl-4-nitrophenol is one of the major breakdown products of fenitrothion [O,O-dimethyl O-(3-methyl-4-nitrophenyl) thiophosphate], a recalcitrant organophosphate insecticide used in agriculture. Being the non-polar methylated aromatic compound, 3-methyl-4-nitrophenol is highly toxic and, therefore, a complete degradation of this compound is important for environmental decontamination/bioremediation purposes. A gram negative, motile Ralstonia sp. SJ98 was isolated by selective screening from a soil sample contaminated with pesticides. The microorganism was capable of utilizing 3-methyl-4-nitrophenol as the sole source of carbon and energy. Thin layer chromatography (TLC), gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), and high performance liquid chromatography (HPLC) were performed to determine the possible intermediates in the degradative pathway of this compound. Taken together, catechol was found to be one of the major intermediate of the pathway. Furthermore, the chemotactic behavior of Ralstonia sp. SJ98 towards 3-methyl-4-nitrophenol was tested using three different methods i.e., drop assay, swarm plate assay and capillary assay, which were found to be positive towards this compound. This is the first report clearly indicating the involvement of a microorganism in the chemotaxis and biodegradation of methyl-4-nitrophenol and formation of catechol as an intermediate in the degradative pathway.

Degradation of 4-nitrocatechol by Burkholderia cepacia: a plasmid-encoded novel pathway

Pseudomonas cepacia RKJ200 (now described as Burkholderia cepacia) has been shown to utilize p-nitrophenol (PNP) as sole carbon and energy source. The present work demonstrates that RKJ200 utilizes 4-nitrocatechol (NC) as the sole source of carbon, nitrogen and energy, and is degraded with concomitant release of nitrite ions. Several lines of evidence, including thin layer chromatography, gas chromatography, 1H-nuclear magnetic resonance, gas chromatography-mass spectrometry, spectral analyses and quantification of intermediates by high performance liquid chromatography, have shown that NC is degraded via 1,2, 4-benzenetriol (BT) and hydroquinone (HQ) formation. Studies carried out on a PNP- derivative and a PNP+ transconjugant also demonstrate that the genes for the NC degradative pathway reside on the plasmid present in RKJ200; the same plasmid had earlier been shown to encode genes for PNP degradation, which is also degraded via HQ formation. It is likely, therefore, that the same sets of genes encode the further metabolism of HQ in NC and PNP degradation.

Indigo production by naphthalene-degrading bacteria

A wild-type naphthalene-degrading strain Pseudomonas putida RKJ1 and two recombinant strains each of Ps. putida and Escherichia coli carrying the genes for naphthalene degradation on a recombinant plasmid pRKJ3, produced indigo and indirubin pigments from indole. Naphthalene, salicylate and IPTG induced cells of naphthalene-degrading recombinant bacteria produced up to two times higher indigo compared with the uninduced cells. The maximum rates of indigo formation by Ps. putida RKJ1, Ps. putida RKJ5/pRKJ3, Ps. putida KT2442/pRKJ3, E. coli TB1/pRKJ3 and E. coli AB1157/pRKJ3 were 0.60, 0.80, 0.60, 1.20 and 1.50 nmol min-1 mg dry biomass-1, respectively, using indole as the substrate. The apparent Km values of indigo formation by these same bacteria were 0.22, 0.15, 0.10, 0. 21 and 0.20 mmol l-1, respectively, again using indole as the substrate. The present study revealed that E. coli AB1157 was the most efficient of the hosts tested for the expression of the plasmid encoded genes (pRKJ3) from the wild-type strain Ps. putida RKJ1. In addition, both recombinant E. coli strains were capable of producing indigo directly from nutrient medium.

Evidence for plasmid-mediated chemotaxis of Pseudomonas putida towards naphthalene and salicylate

A naphthalene (Nap) and salicylate (Sal) degrading microorganism, Pseudomonas putida RKJ1, is chemotactic towards these compounds. This strain carries a 83 kb plasmid. A 25 kb EcoRI fragment of the plasmid contains the genes responsible for Nap degradation through Sal. RKJ5, the plasmid-cured derivative of RKJ1, is neither capable of degradation nor is chemotactic towards Nap or Sal. The recombinant plasmid pRKJ3, which contained a 25 kb EcoRI fragment, was transferred back into the plasmid-free wild-type strain RKJ5, and the transconjugant showed both degradation and chemotaxis. The recombinant plasmid pRKJ3 was also transferred into motile, plasmid-free P. putida KT2442. The resulting transconjugant (RKJ15) showed chemotaxis towards both Nap and Sal. Two mutant strains carrying deletions in pRKJ3 (in KT2442) with phenotypes Nap- Sal+ and Nap- Sal-, were also tested for chemotaxis. It was found that the Nap- Sal+ mutant strain showed chemotaxis towards Sal only, whereas the Nap- Sal- mutant strain is non-chemotactic towards both the compounds. These results suggest that the metabolism of Nap and Sal may be required for the chemotactic activity.

Iodine mediated oxidative cross coupling of 2-aminopyridine and aromatic terminal alkyne: a practical route to imidazo[1,2-a]pyridine derivatives

A novel, transition-metal free route leading to imidazo[1,2-a]pyridine derivatives via iodine mediated oxidative coupling between 2-aminopyridine and aromatic terminal alkyne has been demonstrated. This newly developed method discloses an operationally simple way for the construction of imidazoheterocycles. Commercially available antiulcer drug zolimidine may readily be synthesized employing this method.

Efficiency of naphthalene and salicylate degradation by a recombinant Pseudomonas putida mutant strain defective in glucose metabolism

Metabolically engineered microorganisms may have tremendous potential in removing toxic compounds from nature. In general, microorganisms prefer to utilize simpler carbon sources over toxic compounds when both are present in an environment and, therefore, the presence of simpler carbon sources may greatly reduce the efficiency of a microorganism towards toxic compounds. If a microorganism is prevented from utilizing simpler carbon sources, thereby making it totally dependent upon the toxic compounds, it should increase the specificity for and efficiency of degradation of the toxic compounds in the presence of other, simpler carbon sources. To test this hypothesis, the efficiency of naphthalene and salicylate degradation in the presence of glucose by a recombinant Pseudomonas putida strain mutated in glucose metabolism was determined and compared to the non-mutated strain. Results obtained indicate that the impairment of glucose metabolism leads to better degradation of naphthalene and salicylate in the presence of glucose.

Interrelationship between iodine nutritional status of lactating mothers and their absolutely breast-fed infants in coastal districts of Gangetic West Bengal in India

Iodine nutritional status of 128 lactating mothers and their breast-fed infants (1-3 months) from iodine-replete villages during post-salt iodization period was evaluated. Mothers' urine, blood, and breast milk (BM) and infants' urine and blood were collected and analyzed for iodine and serum FT₄ and TSH estimation. Mothers' and infants' age, parity, occupation, education, and household income were recorded. Median urinary iodine concentration (UIC) of infants was 250 μg/L, indicating their iodine intake was more than adequate. Mothers' median UIC was 185 μg/L, indicating adequate iodine nutrition; however, 13.28% had mild to severe deficiency. Median breast milk iodine concentration (BMIC) was 230 μg/L, which was more than their median UIC 185 μg/L. In iodine-deficient mothers, positive correlation was found between mothers' and infants' serum FT₄ and TSH levels, and negative correlation was found between mothers' and infants' serum FT₄ and TSH levels in excessive iodine nutrition group.

CONCLUSION

Iodine intake of breast-fed infants was at the limit of above requirement, and they are possibly at the risk of excess iodine intake. In iodine deficient and excessive iodine intake mothers, their infants' serum FT₄ and TSH are independent on their iodine nutritional status but dependent on thyroid hormone profile of their mothers but differently. What is Known: • A median urinary iodine of 100 μg/L is used to define adequate iodine intake of lactating mothers and children < 2 years. However, adequate iodine intake in terms of urinary iodine of infants of age 1-3 months is not known. What is New: • Iodine intake of absolutely breast-fed infants (1-3 months) was more than adequate, though their mother's intake was adequate as breast milk contains more iodine than urine. The infants of iodine deficient and excessive iodine intake mothers, infants' hormonal profile is independent of their iodine nutritional status but dependent on their mothers thyroid hormone profile.

Influence of temperature on survival, growth and fecundity of the freshwater snail Indoplanorbis exustus (Deshayes)

To note the effect of temperature on survival, growth and fecundity, newly hatched (zero day old) snails Indoplanorbis exustus were cultured at 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees and 35 degrees C constant temperatures and room temperature (17.5 degrees-32.5 degrees C). Individuals exposed to 10 degrees C died within 3 days while those reared at 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees C and room temperature survived for a period of 6, 27, 18, 16, 12 and 17 weeks respectively. An individual added on an average 0.21 mm and 0.45 mg, 0.35 mm and 7.94 mg, 0.63 mm and 15.5 mg, 0.81 mm and 27.18 mg, 1.07 mm and 41.48 mg and 0.78 mm and 31.2 mg to the shell diameter and body weight respectively at those temperatures per week. The snails cultured at 15 degrees C died prior to attainment of sexual maturity. On an average, an individual produced 31.9 and 582.77, 54.86 and 902.18, 56.01 and 968.45, 49.32 and 798.68 and 62.34 and 1143.97 capsules and eggs respectively at 20 degrees, 25 degrees, 30 degrees, 35 degrees C and room temperature (17.5 degrees-32.5 degrees C).

Segregational and structural instability of recombinant plasmid carrying genes for naphthalene degrading pathway

The stability of recombinant plasmid carrying genes for naphthalene mineralization was determined. A strain of Pseudomonas putida capable of mineralizing naphthalene (Nap+) via salicylate (Sal+) was isolated, and all regulatory and structural genes for the whole pathway were found to be encoded on a 25 kb EcoRI fragment of an approximately 83 kb plasmid present in this strain. The 25 kb EcoRI fragment was cloned into a tetracycline-resistant (TcR) cloning vector pLAFR3 and the recombinant plasmid, pRKJ3 (Nap+, Sal+, TcR), thus obtained was transferred into the plasmid-free strain Pseudomonas putida KT2442 in order to test the stability of the plasmid. Plasmid pRKJ3 was found to be segregationally and/or structurally unstable, depending on the growth conditions. Two types of novel derivative strains having the phenotypes Nap-, Sal+, TcR and Nap-, Sal-, TcR with specific deletions of approximately 2 kb and 18 kb, respectively, were obtained.

Cortical blindness and paraplegia following hypoxic ischemic encephalopathy as a complication of common krait bite

BACKGROUND

A case report of a successful recovery from paraplegia and cortical blindness following anti-venom injection for a snake bite by a common krait is reported here.

CASE

A 14-year old male patient was bitten by a common krait. On admission to a tertiary level hospital, he was started with antivenom serum. But the patient developed sudden respiratory distress following anaphylactic shock and he was kept on ventilation. The patient was discharged with paraplegia with loss of vision. He was diagnosed as a case of cortical blindness due to hypoxic ischemic encephalopathy. Subsequently, the patient recovered from paraplegia and regained visual acuity of 6/60 in both eyes (best corrected). The boy was reexamined after four years.

CONCLUSION

Evaluation of victims of neurotoxic snake bite for early signs of respiratory depression and prompt respiratory assistance, even if anti-venom is not available, is most essential as a life saving measure.

An unusual case of transient cortical blindness with sagittal sinus thrombosis in a case of Henoch-Schonlein purpura

INTRODUCTION

Henoch-Schonlein purpura (HSP) is one of the most common causes of small vessel vasculitis in children, but sometimes may have an atypical presentation.

OBJECTIVE

To report an unusual case of transient cortical blindness in a patient with Henoch-Schonlein purpura.

CASE

A 3-year-old female child was brought with the complaint of diffuse abdominal pain and hematochezia, which was preceded by high grade fever and cough. Three days later she developed hematuria, hematemesis, melena and hemoptysis along with palpable purpura. Four days later she became irritable and developed a few episodes of generalized tonic clonic seizure, followed by cortical blindness. The CT scan of the brain showed bilateral non-enhancing occipital hypodensity. The magnetic resonance venography showed thrombosis in transverse and sigmoid sinus. She was treated with corticosteroids and her mental status and vision improved.

CONCLUSION

The HSP can cause transient cortical blindness, and recovery is good if therapy is initiated at the appropriate time.

A direct entry to polycyclic quinoxaline derivatives via I2-DMSO mediated oxidative decarboxylation of α-amino acids and the subsequent Pictet-Spengler cyclization reaction

A facile and highly efficient iodine-promoted strategy has been delineated for the synthesis of indolo and pyrrolo[1,2-a]quinoxaline derivatives via an oxidative Pictet-Spengler type amino cyclo-annulation reaction using ∝-amino acids as aldehyde surrogates. The concomitant benzylic oxidation and the compatibility of different starting materials under standard conditions made the current method versatile. The salient features of the protocol such as readily available starting materials, inexpensive promoters, environmental benignity, broad substrate scope, scalability, and good to excellent yield make the method more attractive to practitioners of organic synthesis.

Association between berry characters and Solasodine content of solanum khasianum

Correlation between number, grren weight, dry weight and solasodine percent of berry of the treated and control plant progenies in second generation raised from X-rayed (5 KR, 7.5 KR, 10 KR, 12.5 KR and 15 KR), EMS-treated (0.5%, 0.75% and 1% solution in PO (4)-buffer) and untreated dry seeds of Solanum khasianum Clarke revealed that only the numbers of large and small berries had significant correlation with solasodine percent. Correlation between induced variations (CV%) in these characters indicated that selection on berry characters through M (1) and M (2) generations was effective. Dispersion (due to mutagenesis) in the three berry characters have created the base for progressive selection for high solasodine yielders.

An insight on the neuropharmacological activity of Telescopium telescopium--a mollusc from the Sunderban mangrove

The present study was carried out to evaluate the biological properties of the tissue extract of a marine snail Telescopium telescopium, collected from the coastal regions of West Bengal India. On extensive pharmacological screening, it was found that the biological extract of T. telescopium (TTE) produced significant central nervous system (CNS)-depressant activity as observed from the reduced spontaneous motility, potentiation of pentobarbitone induced sleeping time, hypothermia and respiratory depression with transient apnoea. The extract significantly decreased both residual curiosity and also muscle coordination. The fraction, obtained following saturation with 60-80% ammonium sulphate (80S), was also found to demonstrate predominant CNS-depressant activity. It was observed that both TTE and the 80S fraction significantly altered the brain noradrenaline and homovanillic acid levels without affecting the brain gamma amino butyric acid (GABA) concentration. Based on the present observations, it can be suggested that the CNS-depressant effects produced by TTE and 80S could be attributable to modified catecholamine metabolism in the brain.

An unusual case of anisocoria in a child with bleeding aneurysm of posterior communicating artery and idiopathic thrombocytopenic purpura (ITP)

Background: It can give rise to bleeding episodes in different parts of the body including the central nervous system with various systemic manifestations. Case: An eight-year old female child, diagnosed as a case of chronic ITP for last two years, developed intense headache and vomiting for a few days before admission. This was associated with right sided mid dilated pupil with brisk reaction to light. MRI-angiography showed a bleeding aneurysm of posterior communicating artery. The features of raised intra cranial tension subsided with conservative management but the anisocoria persisted. Conclusion: A bleeding aneurysm can manifest with anisocoria as a sign of partial third cranial nerve palsy. Key words: ITP, children, leaking aneurysm, anisocoria DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5276 Nepal J Ophthalmol 2011; 3(2): 191-192  

Hooch blindness: a community study report on a few indoor patients of toxic optic neuropathy following consumption of adulterated alcohol in West Bengal

INTRODUCTION

Hooch blindness following consumption of adulterated alcohol has been known for centuries.

OBJECTIVE

To study cases of mass alcohol intoxication followed by Hooch blindness in eastern India.

MATERIALS AND METHODS

Ten patients of toxic amblyopia collected from a community mass intoxication following consumption of adulterated alcohol were studied. The parameters studied were the findings of ocular examination, applanation tonometry, automated perimetry and visual-evoked potential (VEP). As a part of the special investigations fundus photography and OCT were done. Routine blood examination, fasting lipid profile, postprandial blood sugar estimation were done . All patients were treated with injections of methyl prednisolone and Hydroxy cobalamine, antioxidants and local neuro-protective agents.

RESULTS

Along with diminished vision (from NPL to 3/60), marked pallor of the disc without any other retinal change were noted. The amplitude on VEP was significantly reduced. However, visual improvement (up to 6/18) in 7 patients was observed within 6 weeks of treatment.

CONCLUSION

Hooch blindness in India can be prevented by creating awareness among the target population and reducing the cost of country liquor.

A process report on physical and psychological determiners of social functioning in leprosy patients

Management and rehabilitation of leprosy patients needs information aoout the social acceptance and its association with physical and psychological problems of the affected person. Ninety three leprosy patients (72 male and 21 female) were selected from outpatient department of the hospitals/clinics and their demographic and clinical informations were recorded. The patients were screened for common menta diseases using GHQ-60 (Bengali version). The social functioning was assessed using SSFI. Mean age was 35.19 +/- 12.5 years, 69.9% of the subjects were from urban areas. Multibacillary cases accounted for 60.2% of the cases, 21.5% of the patients had deformity, 53.8% of the patients screened positive for common psychiatric diseases. Social functioning impairment of mild, moderate and severe level was 9.7%, 82.8, and 7.5% respectively. On Univariate analysis, presence of deformity was the only variable showing significant association with moderate to severe degree of social impairment. Using decision tree (Exhaustive CHAID) analysis, presence of deformity along with urban residence was strongly predicted severe social functioning impairment. The results of the study show the need to formulate suitable psychosocial intervention strategy especially in the context of high psychiatric morbidity.

An efficient route towards quinazolinone derivatives via I2-DMSO promoted oxidative decarboxylation of α-amino acid and subsequent oxidative annulation reaction

An efficient and straightforward strategy was revealed to synthesize a wide range of quinazolinone derivatives from commercially inexpensive 2-aminobenzamide and various amino acids via molecular iodine-promoted oxidative decarboxylation of α-amino acid followed by oxidative cyclization reaction. Operational simplicity, consistent yield, functional group tolerance and sustainability are the other noteworthy features of the reaction. A large number of quinazolinone derivatives were conveniently prepared employing the current strategy. The synthesis of other related heteroarenes such as benzoxazole and benzothiazole derivatives following the same reaction condition broadens the scope of the method.

A practical route to arylated dihydroacridine derivatives via nickel boride mediated intramolecular reductive cyclization-concomitant dehydration

A facile and highly efficient route towards 3-aryl-1,2-dihydroacridine derivatives from an aldol adduct of o-nitrobenzaldehyde and cyclohexenone derivatives has been described.

Recent advances in ocular leprosy

Proper MDT soon after detection of leprosy and anti-reaction measures with newer steroids, regular supervision and monitoring of those released from treatment (RFT) reduce the incidence of ocular leprosy to a remarkable extent. Today, most eye complications are because of normal ageing process or of other phenomena in normal healthy population. Cataract and lagophthalmos are the main causes of blindness. However, in India, though the rate of cataract surgical coverage is up to the mark, the same for lagophthalmos is lagging far behind. Integration of management of ocular leprosy into community eye health care service is the talk of the day along with other health care facilities delivered to people affected with leprosy (PAL). Routine eye examinations are necessary for all PB and MB patients, as well as for the RFT persons in order to detect and treat eyes that are at high risk. All eye surgeries can be performed when needed, irrespective of deformities and bacteriological status, by latest microsurgical techniques with good outcome, and better rehabilitation measures. Reorientation training in ocular leprosy is the immediate special need for ophthalmologists, paramedical ophthalmic assistants and eye health care managers working in general hospitals in those areas that were previously "leprosy endemic zones".