Heterotrophic nitrification and aerobic denitrification by the bacterium Pseudomonas stutzeri YZN-001

A strain YZN-001 was isolated from swine manure effluent and was identified as Pseudomonas stutzeri. It can utilise not only nitrate and nitrite, but also ammonium. The strain had the capability to fully remove as much as 275.08 mg L⁻¹ NO₃⁻–N and 171.40 mg L⁻¹ NO₂⁻–N under aerobic conditions. Furthermore, At 30 °C, the utilization of ammonium is approximately 95% by 18 h with a similar level removed by 72 h and 2 weeks at 10 and 4 °C, respectively. Triplicate sets of tightly sealed serum bottles were used to test the heterotrophic nitrifying ability of P. stutzeri YZN-001. The results showing that 39% of removed NH₄⁺–N was completely oxidised to nitrogen gas by 18 h. Indicating that the strain has heterotrophic nitrification and aerobic denitrification abilities, with the notable ability to remove ammonium at low temperatures, demonstrating a potential using the strain for future application in waste water treatment.     

Characterization of alginate lyase (ALYII) from Pseudomonas sp. OS-ALG-9 expressed in recombinant Escherichia coli

An alginate lyase named ALYII was purified to homogeneity from Escherichia coli JM109 carrying a recombinant plasmid, pJK26 harbouring the alyII gene from Pseudomonas sp. OS-ALG-9 by column chromatography with DEAE-cellulose, CM-Sephadex C-50, butyl-Toyopearl 650 M and isoelectric focusing. The molecular size of the purified ALYII was estimated to be 79 kDa by SDS-PAGE and its pI was 8.3. The enzyme was most active at pH 7.0 and 30 °C. Its activity was completely inhibited by Hg²⁺. The enzyme was poly -D-1, 4-mannuronate-specific rather than -D-1, 4-guluronate-specific and it showed a promotion effect in alginate degradation by combination with ALY, an another poly -D-1, 4-mannuronate-specific alginate lyase from the same strain.     

Lipids in the classification of Nocardioides: Reclassification of Arthrobacter simplex (Jensen) lochhead in the genus Nocardioides (Prauser) emend. O'Donnell et al. as Nocardioides simplex comb. nov.

The tubulin proteins of Blastocladiella emersonii have been characterized, and the pool sizes of soluble tubulins measured to evaluate turnover during early development. The axonemal tubulins and soluble tubulin dimers were typical of tubulin proteins from other eukaryotes.[³H]cholchicine binding assays were used to estimate the soluble tubulin pools of zoospores and during early development. The free colchicine-binding pool of tubulin in zoospores represents 1% of the soluble protein. It increases by 49% after encystment (at 30 min), decreases to 21% below the spore level by 50 min, and then increases slowly with growth. Neither deflagellation of zoospores prior to encystment, nor inhibition of axonemal disassembly, alter the postencystment pool increases. Disassembly of cytoskeletal microtubules occurs in either circumstance, but can account for only 54% of the pool increase. It was concluded that (1) the retracted axonemal tubulins are not returned to the soluble pool detected by cholchicine binding and are probably degraded; (2) new microtubules are supplied by the preexisting cytoplasmic pool that expands from disassembly of cytoplasmic microtubules; and (3) that the tubulins of the axonemes and soluble pools may be distinct.     

Rhodopseudomonas sphaeroides forma sp. denitrificans,a denitrifying strain as a subspecies of Rhodopseudomonas sphaeroides

From polluted water of a lagoon pond a new type of denitrifying photosynthetic purple bacteria was isolated. With respect to morphology, fine structure, photopigments, requirement for growth factors, the range of utilization of organic substrates for phototrophic growth and DNA base ratio, the denitrifying strains show the closest resemblance to Rhodopseudomonas sphaeroides and were therefore described as a subspecies named R. sphaeroides forma sp. denitrificans. The new isolates grow well with nitrate anaerobically in the dark accompanying the evolution of nitrogen gas. They cannot assimilate nitrate as the nitrogen source for growth.     

Infection of Glaucocystis nostochinearum (Glaucophyta) by Lagenidium sp. (Oomycota) and its hyperparasite Pythiella sp. (Oomycota)

The glaucophyte Glaucocystis nostochinearum has to our knowledge been observed to be infected by a parasite for the first time. It was found in samples taken from the northernmost freshwater pond in Germany (on the island of Sylt). The fungal parasite was identified as the oomycete Lagenidium sp. which itself was parasitised by another oomycete, Pythiella sp.     

海藻酸裂解酶高产菌株Microbulbifer sp.SH-1的分离、鉴定及其产酶条件优化

【目的】筛选一株海藻酸裂解酶高产菌株,并通过优化产酶条件提高海藻酸裂解酶活性。【方法】以海藻酸钠为唯一碳源的培养基,对福建漳州滨海土壤中的微生物进行筛选和分离,获得海藻酸裂解酶高产菌株;依据形态、生理生化特征及16S rDNA序列分析对目的菌株进行鉴定;然后通过单因素和正交试验对其产酶条件进行优化。【结果】十六烷基吡啶(CPC)染色得到4株透明圈与菌落直径比值(D/d)3的菌株;DNS法测定4菌株发酵液中海藻酸裂解酶活力,其中菌株SH-1的海藻酸裂解酶活性最高,达到315.52 U/mL;经形态、生理生化和16S rDNA测序鉴定,将其命名为Microbulbifer sp. SH-1;通过单因素和正交试验优化,确定该菌株最适产酶培养基为:海藻酸钠10 g/L,NaCl 5 g/L,(NH_4)_2SO_45g/L,MgSO_40.2g/L,K_2HPO_41g/L,FeSO_40.02g/L。对培养条件的进一步优化结果发现,在初始pH 7.5、温度32°C条件下,以1%的接种量将SH-1菌株接入50 mL优化培养基中,240 r/min转速下振荡培养24 h,SH-1菌株产酶最大活性可达757.90 U/mL,比优化前提高了2.4倍。【结论】SH-1最佳产酶条件的建立,为海藻酸裂解酶的大规模制备以及更深层次研究提供了试验基础和理论依据。     

Reduction of Cr(VI) by Desulfovibrio vulgaris and Microbacterium sp.

Many industrial wastes contain Cr(VI), a carcinogen and mutagen, the toxicity of which can be ameliorated by reduction to Cr(III). Microbacterium sp. NCIMB 13776 andDesulfovibrio vulgaris NCIMB 8303 reduced Cr(VI) to Cr(III) anoxically using 25 mM sodium citrate buffer (pH 7), with 25 mM sodium acetate and 25 mM sodium formate as electron donors at 30 °C, under which conditions the rates of reduction of 500 M sodium chromate were 77 and 6 nmol h^–1 mg dry cell wt for D. vulgaris and Microbacterium sp., respectively, these being increased to 127 and 17 nmol h^–1 mg dry cell wt in the presence of 20 mM MOPS/NaOH buffer.     

Fermentation of triacetin and glycerol by Acetobacterium sp. No energy is conserved by acetate excretion

Two strains of homoacetogenic bacteria similar to Acetobacterium carbinolicum were enriched and isolated from freshwater and marine sediment samples with triacetin (glycerol triacetylester) as sole carbon and energy source. Also the type strains of A. carbinolicum and A. woodii were found to be able to grow with triacetin, and to convert it nearly exclusively to acetate. The triacetin-hydrolyzing enzyme was inducible, and was localized in the cytoplasmic fraction of both species at an activity of 0.21–0.26 U mg protein^-1. During fermentation of glycerol, varying amounts of 1,3-propranediol were produced which could be kept at a minimum in a glycerol-limited chemostat. Growth yields in batch and continuous culture experiments varied between 9.2 and 10.9 g mol glycerol^-1 and 6.5 and 7.6 g mol triacetin^-1 with five strains of homoacetogenic bacteria tested. These results indicate that excretion of acetate across the cytoplasmic membrane does not contribute to the energy conservation budget of these homoacetogenic bacteria.Dedicated to Prof. Dr. Holger W. Jannasch on occasion of his 60th birthday     

Heme content of recombinant catalase from Psychrobacter sp. T-3 altered by host Escherichia coli cell growth conditions

The catalase gene of Psychrobacter sp. T-3 was cloned, and the gene product (PktA) was overexpressed in Escherichia coli. The specific activity of the purified PktA was slightly lower than that of the native purified enzyme obtained from Psychrobacter sp. T-3. Spectrophotometric measurements of the purified enzymes suggested that the recombinant PktA contains a mixture of heme b and d, although the native enzyme contains the sole heme b. An addition of the heme precursor 5-aminolevulinic acid (ALA) to the medium increased the heme b content of the recombinant PktA, and the resulting enzyme showed higher specific activity than the native enzyme. This is the first report that shows the heme content of overproduced catalase altered by the host cell growth conditions.     

Lecane segersi n.sp. (Rotifera, Lecanidae) from Thailand

Lecane segersi n.sp. collected from a swamp in Udornthani province, northeastern part of Thailand, is described and figured. It is closely related to the common, warm-stenotherm Lecane papuana (Murray), but distinguished by the presence of inwardly directed antero-lateral spines.     

Two closely related pathways of nicotine catabolism in <Emphasis Type="Italic">Arthrobacter nicotinovorans</Emphasis> and <Emphasis Type="Italic">Nocardioides</Emphasis> sp. strain JS614

A virtually identical nicotine catabolic pathway including the heterotrimeric molybdenum enzyme nicotine and 6-hydroxy-pseudo-oxynicotine dehydrogenase, 6-hydroxy-l-nicotine oxidase, 2,6-dihydroxy-pseudo-oxynicotine hydrolase, and 2,6-dihydroxypyridine hydroxylase have been identified in A. nicotinovorans and Nocardioides sp. JS614. Enzymes catalyzing the same reactions and similar protein antigens were detected in the extracts of the two microorganisms. Nicotine blue and methylamine, two end products of nicotine catabolism were detected in the growth medium of both bacterial species. Nicotine catabolic genes are clustered on pAO1 in A. nicotinovorans, but located chromosomally in Nocardioides sp. JS614.     

Phyllodiaptomus praedictus n. sp. (Copepoda,Calanoida) from Thailand

Phyllodiaptomus praedictus n. sp. is described from the Bangkok area. It might be endemic to Thailand. It belongs to the blanci-group of species, and is most closely related to P. annae and P. wellekensae.     

Purification, characterization, and cloning of trimethylamine dehydrogenase fromMethylophaga sp. strain SK1

Trimethylamine dehydrogenase (TMADH, EC 1.5.99.7), an iron-sulfur flavoprotein that catalyzes the oxidative demethylation of trimethylamine to form dimethylamine and formaldehyde, was purified fromMethylophaga sp. strain SK1. The active TMADH was purified 12.3-fold through three purification steps. The optimal pH and temperature for enzyme activity was determined to be 8.5 and 55°C, respectively. TheV _max andK _m values were 7.9 nmol/min/mg protein and 1.5 mM. A genomic DNA of 2,983 bp fromMethylophaga sp. strain SK1 was cloned, and DNA sequencing revealed the open reading frame (ORF) of the gene coding for TMADH. The ORF contained 728 amino acids with extensive identity (82%) to that ofMethylophilus methylotrophus W₃A₁.     

Eodiaptomus shihi n. sp. (Copepoda,Calanoida) from central India

Eodiaptomus shihi n. sp. is described from the material collected from Gandhisagar reservoir, River Narmada and a hillpool in the Madhya Pradesh State of central India. The salient features of this new species include: in female, the left metasomal wing is strongly developed, and the endopodite in leg 5 is 2-segmented and longer than first exopodite-segment; in male, the right caudal ramus is armed with a tooth-like chitinous structure near ventro-distal region, and in right leg 5, the basis is devoid of any hyaline lobe on inner margin and the first exopodite-segment is produced into a large spinous process at disto-outer corner.     

Arctodiaptomus (Rhabdodiaptomus) michaeli n.sp. (Copepoda,Calanoida) from Kashmir,India

Arctodiaptomus (Rhabdodiaptomus) michaeli n.sp. is described from the material collected in Alapathar Lake and Marsar Lake of Kashmir, India.     

Mineralization of phenol and its derivatives by Pseudomonas sp. strain CP4

A Pseudomonas sp. strain, CP4, was isolated that used phenol up to 1.5 g/l as sole source of carbon and energy. Optimal growth on 1.5 g phenol/l was at pH 6.5 to 7.0 and 30°C. Unadapted cells needed 72 h to decrease the chemical oxygen demand (COD) of about 2000 mg/l (from 1 g phenol/l) to about 200 mg/l. Adapted cells, pregrown on phenol, required only 65 h to decrease the COD level to below 100 mg/l. Adaptation of cells to phenol also improved the degradation of cresols. Cell-free extracts of strain CP4 grown on phenol or o-, m- or p-cresol had sp. act. of 0.82, 0.35, 0.54 and 0.32 units of catechol 2,3-dioxygenase and 0.06, 0.05, 0.05 and 0.03 units of catechol 1,2-dioxygenase, respectively. Cells grown on glucose or succinate had neither activity. Benzoate and all isomers of cresol, creosote, hydroxybenzoates, catechol and methyl catechol were utilized by strain CP4. No chloroaromatic was degraded, either as sole substrate or as co-substrate.The authors are with the Department of Microbiology and Bioengineering, Central Food Technological Research Institute, Mysore-570 013, India     

Xylanase production by Burkholderia sp. DMAX strain under solid state fermentation using distillery spent wash

Xylanase production by a newly isolated strain of Burkholderia sp. was studied under solid state fermentation using anaerobically treated distillery spent wash. Response surface methodology (RSM) involving Box-Behnken design was employed for optimizing xylanase production. The interactions between distillery effluent concentration, initial pH, moisture ratio and inoculum size were investigated and modeled. Under optimized conditions, xylanase production was found to be in the range of 5200-5600 U/g. The partially purified enzyme recovered after ammonium sulphate fractionation showed maximum activity at 50 degrees C and pH 8.6. Kinetic parameters like Km and Vmax for xylan were found to be 12.75 mg/ml and 165 micromol/mg/min. In the presence of metal ions such as Ca2+, Co2+, Mn2+, Ba2+, Mg2+ and protein disulphide reducing agents such as beta-mercaptoethanol and dithiotheritol (DTT) the activity of enzyme increased, where as strong inhibition of enzyme activity was observed in the presence of Cu2+, Ag+, Fe2+ and SDS. The crude enzyme hydrolysed lignocellulosic substrate, wheat bran as well as industrial pulp.     

The cloned 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene from Sinorhizobium sp. strain BL3 in Rhizobium sp. strain TAL1145 promotes nodulation and growth of Leucaena leucocephala

The objective of this study was to determine the role of 1-aminocyclopropane-1-carboxylate (ACC) deaminase of symbionts in nodulation and growth of Leucaena leucocephala. The acdS genes encoding ACC deaminase were cloned from Rhizobium sp. strain TAL1145 and Sinorhizobium sp. BL3 in multicopy plasmids, and transferred to TAL1145. The BL3-acdS gene greatly enhanced ACC deaminase activity in TAL1145 compared to the native acdS gene. The transconjugants of TAL1145 containing the native or BL3 acdS gene could grow in minimal media containing 1.5mM ACC, whereas BL3 could tolerate up to 3mM ACC. The TAL1145 acdS gene was inducible by mimosine and not by ACC, while the BL3 acdS gene was highly inducible by ACC and not by mimosine. The transconjugants of TAL1145 containing the native- and BL3-acdS genes formed nodules with greater number and sizes, and produced higher root mass on L. leucocephala than by TAL1145. This study shows that the introduction of multiple copies of the acdS gene increased ACC deaminase activities of TAL1145 and enhanced its symbiotic efficiency on L. leucocephala.