Biomedical subjects

B K Patel

Publications and source records attributed to B K Patel.

At least 91 records · Page 5Linked to original sources

PubMed1996

Stat6 and Jak1 are common elements in platelet-derived growth factor and interleukin-4 signal transduction pathways in NIH 3T3 fibroblasts.

Both platelet-derived growth factor (PDGF) and interleukin-4 (IL-4) play major roles in cell proliferation, differentiation, chemotaxis, and other functional responses. Here, we demonstrate that Stat6, previously shown to be activated by only IL-4 and IL-3, becomes activated after PDGF stimulation of NIH 3T3 fibroblasts. PDGF BB, and to a lesser extent PDGF AA, rapidly induced DNA binding activity from NIH 3T3 cell lysates utilizing the immunoglobulin heavy chain germ line epsilon promoter (Iepsilon) that specifically binds to Stat6 in an electrophoretic mobility shift assay. DNA binding activity could be detected within 5 min and reached maximum levels at approximately 20 min in parental NIH 3T3 cells. An identical mobility shift and time course of PDGF-mediated Iepsilon binding activity was more pronounced in lysates of NIH 3T3 transfectants overexpressing human Stat6 (NIH 3T3-Stat6). The observed radiolabeled Iepsilon mobility shift was competed by unlabeled Iepsilon as well as by the beta-casein gene promoter but not by the interferon-alpha-stimulated response element or the interferon-gamma response region of the guanylate-binding protein gene. A Stat6-specific polyclonal antisera also supershifted the PDGF-induced Iepsilon mobility shift. After PDGF BB treatment, a 100-kDa tyrosine phosphorylated species was detected in anti-Stat6 immunoprecipitates. Cycloheximide had little effect on Stat6 tyrosine phosphorylation. In addition to Stat6, Stat5a, and Stat5b, PDGF BB also induced Jak1 tyrosine phosphorylation suggesting a potential pathway for Stat activation. Strikingly, the concurrent addition of IL-4 enhanced PDGF BB-induced Iepsilon binding activity, Jak1 tyrosine phosphorylation, and [3H]thymidine incorporation. These results provide evidence that Stat6 and Jak1 are common elements in PDGF and IL-4 signaling pathways and suggest that IL-4 could play a role in potentiating certain known PDGF-induced biological responses.

3T3 Cells↗

PubMed1996

Rapid distinction between Leptonema and Leptospira by PCR amplification of 16S-23S ribosomal DNA spacer.

The PCR amplification of the genomic DNA of Leptonema illini strain 3055 using primers directed against conserved regions of the rRNA operon provided evidence that the 16S and 23S rRNA genes were linked via an intergenic spacer region. The sequencing of the intergenic spacer region indicated that it was 435 nucleotides in length and sequence similarity searches revealed that it bore no homology to any known sequences including tRNA available in databases. Further investigations using Southern blot hybridization revealed that there were two copies of these linked genes in the genome. However, similar PCR studies on a representative strain from each of the 23 serogroups of Leptospira interrogans, which are pathogenic, and eight strains from the 6 serogroups of Leptospira biflexa, which are non-pathogenic, revealed that the 16S and 23S rRNA genes were not linked.

Base Sequence↗

PubMed1996

A novel thermostable dextranase from a Thermoanaerobacter species cultured from the geothermal waters of the Great Artesian Basin of Australia.

A Gram-negative sporulating thermophilic anaerobe, designated AB11Ad, was isolated from the heated waters of the Great Artesian Basin of Australia. It grew on a variety of carbohydrates including glucose, starch, and dextran and produced a thermostable and thermoactive extracellular endo-dextranase. The enzyme was produced more actively under pH controlled continuous culture conditions than under batch conditions. Ammonium sulfate precipitated crude dextranase exhibited a temperature optimum of 70 degrees C and a pH optimum between 5 and 6. The half life was approximately 6.5 h at 75 degrees C and 2 h at 80 degrees C at pH 5.0 and in the absence of added dextran. 16S rRNA sequence analysis indicated that isolate AB11Ad was a member of the genus Thermoanaerobacter.

Australia↗

PubMed1996

Characterization of a new obligately anaerobic thermophile, Thermoanaerobacter wiegelii sp. nov.

An obligately anaerobic, extremely thermophilic Thermoanaerobacter species was isolated from a freshwater pool formed from a geothermally heated (56 to 69 degrees C) water outlet in Government Gardens, Rotorua, New Zealand. This organism was a spore-forming, gram-negative, rod-shaped bacterium. Strain Rt8.B1T (= DSM 10319T) (T = type strain) fermented a wide variety of mono-, di-, and polysaccharides and produced ethanol, acetate, lactate, propionate, and hydrogen. Sugar alcohols were also fermented, but organic acids and amino acids were not utilized. On the basis of its morphological characteristics, DNA G + C content, obligately anaerobic, thermophilic, polysaccharolytic nature, and levels of 16S rRNA sequence homology, we propose that strain Rt8.B1T should be classified in the genus Thermoanaerobacter as a new species, Thermoanaerobacter wiegelii.

Bacteria, Anaerobic↗

PubMed1996

Fervidobacterium gondwanense sp. nov., a new thermophilic anaerobic bacterium isolated from nonvolcanically heated geothermal waters of the Great Artesian Basin of Australia.

A new thermophilic, carbohydrate-fermenting, obligately anaerobic bacterial species was isolated from a runoff channel formed from flowing bore water from the geothermally heated aquifer of the Great Artesian Basin of Australia. The cells of this organism were nonsporulating, motile, gram negative, and rod shaped and generally occurred singly or in pairs. The optimum temperature for growth was 65 to 68 degrees C, and no growth occurred at temperatures below 44 degrees C or above 80 degrees C. Growth was inhibited by 10 micrograms of lysozyme per ml, 10 micrograms of penicillin per ml, 10 micrograms of tetracycline per ml, 10 micrograms of phosphomycin per ml, 10 micrograms of vancomycin per ml, 10 micrograms of vancomycin per ml, and NaCl concentrations greater than 0.2%. The optimum pH for growth was 7.0, and no growth occurred at pH 5.5 or 8.5. The DNA base composition was 35 mol% guanine plus cytosine, as determined by thermal denaturation. The end products of glucose fermentation were lactate, acetate, ethanol, CO2, and H2. Sulfur, but not thiosulfate, sulfite, or sulfate, was reduced to sulfide. Phase-contrast microscopy of whole cells and an electron microscopic examination of thin sections of cells revealed the presence of single terminal spheroids, a trait common in members of the genus Fervidobacterium. However, a phylogenetic analysis of the 16S rRNA sequence revealed that the new organism could not be assigned to either of the two previously described Fervidobacterium species. On the basis of these observations, we propose that the new organism should be designated a new Fervido-bacterium species, Fervidobacterium gondwanense. The type strain of this species is strain AB39 (= Australian Collection of Microorganisms strain ACM 5017.

Australia↗

PubMed1996

Desulfovibrio gabonensis sp. nov., a new moderately halophilic sulfate-reducing bacterium isolated from an oil pipeline.

Two moderately halophilic sulfate-reducing bacteria were isolated from an African oil pipeline and designated strains SEBR 3640 and SEBR 2840T (T = type strain). Both of these strains possess traits that define the genus Desulfovibrio. The cells of both isolates were motile curved rods that had a single polar flagellum and contained desulfoviridin, and both isolates utilized lactate, pyruvate, malate, fumarate, succinate, and ethanol in the presence of sulfate. Sulfite, thiosulfate, and elemental sulfur were also used as an electron acceptors in the presence of lactate. However, both strains tolerated higher concentrations of NaCl (up to 17%) than all other Desulfovibrio species except Desulfovibrio halophilus, which tolerated a similar level of NaCl. The results of a 16S rRNA gene sequence analysis also placed the designated type strain, strain SEBR 2840, in the genus Desulfovibrio but revealed that this organism was significantly different from D. halophilus and all other validly described Desulfovibrio species. On the basis of our results, we propose that strain SEBR 2840T is a member of a new species of the genus Desulfovibrio, Desulfovibrio gabonensis. The type strain of D. gabonensis is strain SEBR 2840 (= DSM 10636).

Base Sequence↗

PubMed1996

Clostridium proteoclasticum sp. nov., a novel proteolytic bacterium from the bovine rumen.

A novel proteolytic bacterium was isolated from rumen contents of New Zealand cattle grazing fresh forage and was designated strain B316(T) (T = type strain). Strain B316(T) cells were straight to slightly curved rods (width, 0.4 to 0.6 microns; length, 1.3 to 3.0 microns) that were gram-positive and possessed a single subterminal flagellum. This isolate did not produce catalase, indole, ammonia, lipase, or lecithinase, or reduce nitrate, but it did produce a curd reaction with milk. Strain B316(T) was proteolytic, hydrolyzing casein and fraction I leaf protein. The crude proteinase was predominantly the serine type, but some cysteine proteinase and metallo-proteinase activities were also detected. The DNA base composition of strain B316(T) was 28 mol% G+C. A 16S ribosomal DNA sequence analysis of strain B316(T) indicated that it was most closely related to a member of clostridial cluster XIVa, viz., Clostridium aminophilum, an amino acid-fermenting organism isolated from the rumen; the similarity value was 92.2%. The results of the phenotypic characterization analysis, G+C content analysis, and phylogenetic analysis of the 16S ribosomal DNA sequence set strain B316(T) apart from all of the members of cluster XIVa. We propose that strain B316(T) should be designated a new species of the genus Clostridium, Clostridium proteoclasticum. Strain B316 is the type strain and has been deposited in the American Type Culture Collection as strain ATCC 51982.

Animals↗

PubMed1996

L-alanine production from glucose fermentation by hyperthermophilic members of the domains bacteria and Archaea: a remnant of an ancestral metabolism?

New members of the order Thermotogales were isolated from nonvolcanically heated geothermal environments, including oil fields and waters of the Great Artesian Basin of Australia, thereby extending their known habitats, previously recognized primarily as volcanic. The hyperthermophilic and thermophilic members of Thermotogales of volcanic origin, together with the recently described nonvolcanic species of this order and three new isolates described in this paper, were all found to produce L-alanine from glucose fermentation, in addition to acetate, lactate, CO2 and H2. L-alanine production from glucose is a trait in common with Pyrococcus furiosus and Thermococcus profundus. We propose that L-alanine production from sugar fermentation be regarded as an ancestral metabolic characteristic.

Alanine↗

PubMed1996

Pancreaticocystostomy revision for obstructive pancreatitis and pancreatic fistula after segmental pancreatic transplantation.

Combined kidney-pancreas transplantation is an effective surgical therapy for end-stage renal failure secondary to type I diabetes mellitus. However, obstructive pancreatitis and pancreaticocutaneous fistula remain significant postoperative complications unique to extraperitoneal segmental pancreatic transplantation. We present our experience with 13 patients (7 with obstructive pancreatitis and 6 with pancreaticocutaneous fistulae) after segmental extraperitoneal pancreatic transplantation, who subsequently underwent intraperitoneal reconstruction of the pancreaticocystostomy. This reconstruction was successful in 11 of 13 (85%) patients with minimal morbidity and no mortality. This intraperitoneal approach to reconstruction of the pancreaticocystostomy after segmental extraperitoneal pancreatic transplantation is a safe and effective means of graft salvage and this technique has not been described in the literature.

Adult↗

PubMed1995

Reevaluating the classification of Halobacteroides and Haloanaerobacter species based on sequence comparisons of the 16S ribosomal RNA gene.

The 16S rRNA gene (rDNA) sequence analysis of four halophilic anaerobes: Halobacteroides halobius, H. lacunaris. Haloanaerobacter (Hb.) chitinovorans and H. acetoethylicus confirmed that they were all members of the family Haloanaerobiaceae. H. lacunaris and H. halobius were found to be more closely related to each other and were distantly related to Sporohalobacter lortetti and the members of the genera Haloanaerobium and Halothermothrix. These data are in agreement with their assignment to the genus Halobacteroides. Further analysis indicated that Hb. chitinovorans was closely affiliated to members of the genus Halobacteroides, and therefore we propose to transfer it to the genus Halobacteroides as H. chitinovorans comb. nov. This transfer would invalidate the genus Haloanaerobacter, as Hb. chitinovorans is the only member of this genus. The 16S rDNA sequence analysis of H. acetoethylicum indicated that it was very closely related to members of the genus Haloanaerobium, viz. Haloanaerobium (Ha.) praevalens, Ha. salsugo, and Ha. alcaliphilum, and hence we propose to transfer it to the genus Haloanaerobium as Ha. acetoethylicus comb. nov.

Base Composition↗

PubMed1995

Bacillus thermoamylovorans sp. nov., a moderately thermophilic and amylolytic bacterium.

A moderately thermophilic, facultatively anaerobic, amylolytic bacterium was isolated from palm wine, a tropical alcoholic beverage that was sampled in Senegal. The cells were gram positive, catalase positive, non-spore forming, rod shaped, and slightly motile with peritrichous flagella. The strain which we examined did not possess cytochrome and produced L-(+)-lactate, acetate, ethanol, and formate but not hydrogen during carbohydrate fermentation. Growth occurred at pH values ranging from 5.4 to 8.5, and optimum growth occurred at around pH 7.0. The optimum temperature for growth was around 50 degrees C, and the upper temperature limit for growth was 58 degrees C. The guanine-plus-cytosine content of the DNA was 38.8 +/- 0.2 mol%. A sequence analysis of the 16S rRNA gene revealed that the new organism is closely related phylogenetically to members of genus Bacillus. Despite the lack of spores, we propose that on the basis of phylogenetic characteristics, the new isolate should be classified as a new Bacillus species, Bacillus thermoamylovorans. The type strain is strain DKP (= Collection of Institut Pasteur CNCM I-1378).

Bacillus↗

PubMed1995

Isolation and characterization of a thermophilic sulfate-reducing bacterium, Desulfotomaculum thermosapovorans sp. nov.

Strain MLFT (T = type strain), a new thermophilic, spore-forming sulfate-reducing bacterium, was characterized and was found to be phenotypically, genotypically, and phylogenetically related to the genus Desulfotomaculum. This organism was isolated from a butyrate enrichment culture that had been inoculated with a mixed compost containing rice hulls and peanut shells. The optimum temperature for growth was 50 degrees C. The G+C content of the DNA was 51.2 mol%. Strain MLFT incompletely oxidized pyruvate, butyrate, and butanol to acetate and presumably CO2. It used long-chain fatty acids and propanediols. We observed phenotypic and phylogenetic differences between strain MLFT and other thermophilic Desulfotomaculum species that also oxidize long-chain fatty acids. On the basis of our results, we propose that strain MLFT is a member of a new species, Desulfotomaculum thermosapovorans.

DNA, Bacterial↗

PubMed1995

Haloanaerobium alcaliphilum sp. nov., an anaerobic moderate halophile from the sediments of Great Salt Lake, Utah.

A strictly anaerobic, moderately halophilic, gram-negative, rod-shaped bacterium was isolated from Great Salt Lake, Utah, sediments and designated GSLST (T = type strain). Strain GSLST grew optimally at pH 6.7 to 7.0 but had a very broad pH range for growth (pH 5.8 to 10.0). The optimum temperature for growth was 37 degrees C, and no growth occurred at 15 or 55 degrees C. The optimum salt concentration for growth was 10%. Strain GSLST required yeast extract and Trypticase peptone to ferment carbohydrates, pyruvate, and glycine betaine. Strain GSLST was resistant to penicillin, D-cycloserine, tetracycline, and streptomycin. The G + C content of this isolate was 31 mol%. The fermentation products from glucose utilization were acetate, butyrate, lactate, CO2, and H2, and in addition strain GSLST fermented glycine betaine to acetate and trimethylamine. All of these traits distinguish this organism from all previously described halophilic anaerobes. The 16S rRNA gene sequence of strain GSLST was found to be similar to, but also significantly different from, the 16S rRNA sequences of Haloanaerobium salsugo and Haloanaerobium praevalens. Therefore, strain GSLST (= DSM 8275T) is described as a new species, Haloanaerobium alcaliphilum.

DNA, Bacterial↗

PubMed1995

Thermotoga elfii sp. nov., a novel thermophilic bacterium from an African oil-producing well.

A thermophilic, glucose-fermenting, strictly anaerobic, rod-shaped bacterium, strain SEBR 6459T (T = type strain), was isolated from an African oil-producing well. This organism was identified as a member of the genus Thermotoga on the basis of the presence of the typical outer sheath-like structure (toga) and 16S rRNA signature sequences and its ability to grow on carbohydrates (glucose, arabinose, fructose, lactose, maltose, and xylose). Major differences in its 16S rRNA gene sequence, its lower optimum temperature for growth (66 degrees C), its sodium chloride range for growth (0 to 2.8%), its lack of lactate as an end product from glucose fermentation, and its peritrichous flagella indicate that strain SEBR 6459T is not similar to the three previously described Thermotoga species. Furthermore, this organism does not belong to any of the other genera related to the order Thermotogales that have been described. On the basis of these findings, we propose that this strain should be described as a new species, Thermotoga elfii. The type strain of T. elfii is SEBR 6459 (= DSM 9442).

Africa↗

PubMed1995

Description of Thermoanaerobacter brockii subsp. lactiethylicus subsp. nov., isolated from a deep subsurface French oil well, a proposal to reclassify Thermoanaerobacter finnii as Thermoanaerobacter brockii subsp. finnii comb. nov., and an emended description of Thermoanaerobacter brockii.

A strictly anaerobic, thermophilic, gram-positive, spore-forming cubacterium designated strain SERB 5268T (T = type strain) was isolated from an oil field at a depth of 2,100 m, where the temperature was 92 degrees C. The cells of this organism were gram-positive, straight, motile rods (0.5 by 2 to 3 microns) with peritrichous flagella. The cells occurred singly or in pairs during the logarithmic growth phase, but were pleomporphic and filamentous (length, 15 microns) in old cultures. Growth occurred at temperatures of 40 to 75 degrees C, and optimum growth occurred at temperatures between 55 and 60 degrees C. The fermentable substrates included glucose, fructose, galactose, mannose, cellobiose, maltose, sucrose, lactose, D-xylose, D-ribose, mannitol, pyruvate, and starch. The products of fermentation of glucose were lactate, acetate, ethanol, H2, and CO2. The DNA base composition was 35 mol% G+C. The results of 16S rRNA sequence comparisons indicated that strain SEBR 5268T was closely related to Thermoanaerobacter brockii and Thermoanaerobacter finnii, and these three organisms exhibited levels of ribosomal DNA sequence homology of 98 to 99%. The results of DNA-DNA hybridization studies performed with the three organisms confirmed this close affiliation, and as base pairing values of > 70% were obtained, these organisms belong to the same species. Therefore, we propose that T. finnii should be reclassified as a subspecies of T. brockii, Thermoanaerobacter brockii subsp. finnii comb. nov. This automatically creates Thermoanaerobacter brockii subsp. brockii. We also propose that strain SEBR 5268T should be classified as a member of a new subspecies of T. brockii, Thermoanaerobacter brockii subsp. lactiehylicus.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria, Anaerobic↗

PubMed1995

Haloanaerobium lacusroseus sp. nov., an extremely halophilic fermentative bacterium from the sediments of a hypersaline lake.

A new extremely halophilic chemoorganotrophic bacterium (strain H200T [T = type strain]) was isolated from the hypersaline sediments of Retba Lake in Senegal. This organism was a sluggishly motile, rod-shaped, non-spore-forming, gram-negative, obligate anaerobe that grew optimally at 40 degrees C in the presence of 180 to 200 g of NaCl per liter. The DNA base composition was 32 mol% guanine plus cytosine. The fermentation products from glucose were ethanol, acetate, H2, and CO2. Yeast extract was required for growth. The fermentable substrates included D-fructose, galactose, D-xylose, cellobiose, lactose, maltose, sucrose, starch, D-mannitol, glycerol, and Casamino Acids. On the basis of the results of a 16S rRNA sequence analysis, strain H200T was found to be related to Haloanaerobium species. The 16S rRNA sequence of strain H200T differed from the sequences of the three previously described Haloanaerobium species, and strain H200T also differed from these organisms in its NaCl range for growth (60 to 340 g/liter); strain H200T grew in the presence of the highest NaCl concentration recorded for any halophilic anaerobic organism, including the three previously described Haloanaerobium species. We propose that strain H200T (= DSM 10165) belongs to a new Haloanaerobium species, Haloanaerobium lacusroseus.

Base Sequence↗

PubMed1994

Phylogeny and lipid composition of Thermonema lapsum, a thermophilic gliding bacterium.

1,490 nucleotides of the 16S rRNA gene of a Gram-negative, thermophilic and gliding bacterium, Thermonema lapsum, have been sequenced. Phylogenetic analysis indicates that T. lapsum is related to cytophaga-flavobacteria-bacteroides (CFB) and is confirmed by the identification signature nucleotides that define this group. Further phylogenetic analysis indicates that T. lapsum forms the deepest branch in the CFB group; this observation was confirmed by the identification of unique nucleotide and nucleotide pairs which separate T. lapsum from all other members of this group. The phospholipid fatty acid (PLFA) profile also confirmed that T. lapsum is related to the cytophaga-flavobacteria-bacteroides group and also to selected members of the genus Flexibacter; the PLFA profile is unique to T. lapsum.

Bacteria, Aerobic↗

PubMed1994

Desulfovibrio longreachii sp. nov., a sulfate-reducing bacterium isolated from the Great Artesian Basin of Australia.

A new mesophilic, thermotolerant sulfate-reducing bacterium, was isolated from the flowing bore waters of a deep aquifer, the Great Artesian Basin, Australia. The strain, designated isolate AB16910a, is a curved rod and resembled members of the genus Desulfovibrio. However, the isolate can be differentiated from other members of the Desulfovibrio species because of the high G+C content of 69 +/- 0.25% the 16S rRNA sequence data and other physiological characteristics. The name Desulfovibrio longreachii is proposed for the new isolate.

Australia↗