Isolation and molecular identification of planctomycete bacteria from postlarvae of the giant tiger prawn, Penaeus monodon

Bacteria phenotypically resembling members of the phylogenetically distinct planctomycete group of the domain Bacteria were isolated from postlarvae of the giant tiger prawn, Penaeus monodon. A selective medium designed in the light of planctomycete antibiotic resistance characteristics was used for this isolation. Planctomycetes were isolated from both healthy and monodon baculovirus-infected prawn postlarvae. The predominant colony type recovered from postlarvae regardless of viral infection status was nonpigmented. Other, less commonly observed types were pink or orange pigmented. A planctomycete-specific 16S rRNA-directed probe was designed and used to screen the isolates for their identity as planctomycetes prior to molecular phylogenetic characterization. 16S rRNA genes from nine prawn isolates together with two planctomycete reference strains (Planctomyces brasiliensis and Gemmata obscuriglobus) were sequenced and compared with reference sequences from the planctomycetes and other members of the domain Bacteria. Phylogenetic analyses and sequence signatures of the 16S rRNA genes demonstrated that the prawn isolates were members of the planctomycete group. Five representatives of the predominant nonpigmented colony type were members of the Pirellula group within the planctomycetes, as were three pink-pigmented colony type representatives. Homology values and tree topology indicated that representatives of the nonpigmented and pink-pigmented colony types formed two discrete clusters within the Pirellula group, not identical to any known Pirellula species. A sole representative of the orange colony type was a member of the Planctomyces group, virtually identical in 16S rDNA sequence to P. brasiliensis, and exhibited distinctive morphology.     

Discontinuous occurrence of the hsp70 (dnaK) gene among Archaea and sequence features of HSP70 suggest a novel outlook on phylogenies inferred from this protein

Occurrence of the hsp70 (dnaK) gene was investigated in various members of the domain Archaea comprising both euryarchaeotes and crenarchaeotes and in the hyperthermophilic bacteria Aquifex pyrophilus and Thermotoga maritima representing the deepest offshoots in phylogenetic trees of bacterial 16S rRNA sequences. The gene was not detected in 8 of 10 archaea examined but was found in A. pyrophilus and T. maritima, from which it was cloned and sequenced. Comparative analyses of the HSP70 amino acid sequences encoded in these genes, and others in the databases, showed that (i) in accordance with the vicinities seen in rRNA-based trees, the proteins from A. pyrophilus and T. maritima form a thermophilic cluster with that from the green nonsulfur bacterium Thermomicrobium roseum and are unrelated to their counterparts from gram-positive bacteria, proteobacteria/mitochondria, chlamydiae/spirochetes, deinococci, and cyanobacteria/chloroplasts; (ii) the T. maritima HSP70 clusters with the homologues from the archaea Methanobacterium thermoautotrophicum and Thermoplasma acidophilum, in contrast to the postulated unique kinship between archaea and gram-positive bacteria; and (iii) there are exceptions to the reported association between an insert in HSP70 and gram negativity, or vice versa, absence of insert and gram positivity. Notably, the HSP70 from T. maritima lacks the insert, although T. maritima is phylogenetically unrelated to the gram-positive bacteria. These results, along with the absence of hsp70 (dnaK) in various archaea and its presence in others, suggest that (i) different taxa retained either one or the other of two hsp70 (dnaK) versions (with or without insert), regardless of phylogenetic position; and (ii) archaea are aboriginally devoid of hsp70 (dnaK), and those that have it must have received it from phylogenetically diverse bacteria via lateral gene transfer events that did not involve replacement of an endogenous hsp70 (dnaK) gene.     

Conversion of pBR322-based plasmids into broad-host-range vectors by using the Tn3 transposition mechanism

We constructed a series of transposon vectors which allow efficient in vitro gene manipulation and subsequent introduction of cloned DNA into a variety of gram-negative bacteria. Transfer of the cloned fragment from these multicopy plasmids into self-transmissible broad-host-range vectors is achieved in vivo, using the Tn3 transposition mechanism. Transposition into a variety of broad-host-range plasmids proceeds efficiently, and the resulting recombinant plasmids can be readily transferred and maintained in a variety of gram-negative bacteria. The utility of the transposable vectors was demonstrated by the introduction and expression of the lacIPOZY sequences of Escherichia coli into Pseudomonas putida strains, allowing them to utilize lactose as a sole source of carbon and energy.     

The effects of incremental submaximal exercise on circulating leukocytes in physically active and sedentary males and females

The presence of HIV-1 DNA sequence variants of pediatric AIDS patients was investigated in a two-stage polymerase chain reaction (PCR) using nested primers for the first and second (V1-V2) hypervariable regions of the proviral envelope (gp 120) gene (env1). Gel electrophoresis analysis yielded amplified DNA bands which exhibited length variations which were characteristic for each child. The PCR products were cloned and the resulting clones demonstrated inserts of different lengths in a patient and between patients. Analysis of five clones from two different patients at the level of DNA sequencing indicates an extreme heterogeneity in the V1-V2 region. DNA maximum similarity between all of the isolated clones ranged between 69 to 96%. Comparison between DNA sequences of the isolated clones and HIV-1 strains of other parts of the world was also performed. The highest percentage of similarity that was found with known HIV variants included the following strains: HIVADA, HIVJFL, HIVSW42, HIVSWB83, HIVTRA2, HIVWMJ22. The sequences also showed a high degree of similarity to the clade B virus HIVSF162. The analyzed HIV-1 sequences demonstrated the expected high degree of variation in the V1-V2 region of the envelope gene and in some cases that the variation between isolates from the same patient may exceed the variation between the individual clones and the reference HIV-1 strains.     

Evolutionary genetics of the isocitrate dehydrogenase gene (icd) in Escherichia coli and Salmonella enterica

Sequences of the icd gene, encoding isocitrate dehydrogenase (IDH), were obtained for 33 strains representing the major phylogenetic lineages of Escherichia coli and Salmonella enterica. Evolutionary relationships of the strains based on variation in icd are generally similar to those previously obtained for several other housekeeping and for invasion genes, but the sequences of S. enterica subspecies V strains are unusual in being almost intermediate between those of the other S. enterica subspecies and E. coli. For S. enterica, the ratio of synonymous (silent) to nonsynonymous (replacement) nucleotide substitutions between pairs of strains was larger than comparable values for 12 other housekeeping and invasion genes, reflecting unusually strong purifying selection against amino acid replacement in the IDH enzyme. All amino acids involved in the catalytic activity and conformational changes of IDH are strictly conserved within and between species. In E. coli, the level of variation at the 3' end of the gene is elevated by the presence in some strains of a 165-bp replacement sequence supplied by the integration of either lambdoid phage 21 or defective prophage element e14. The 72 members of the E. coli Reference Collection (ECOR) and five additional E. coli strains were surveyed for the presence of phage 21 (as prophage) by PCR amplification of a phage 21-specific fragment in and adjacent to the host icd, and the sequence of the phage 21 segment extending from the 3' end of icd through the integrase gene (int) was determined in nine strains of E. coli. Phage 21 was found in 39% of E. coli strains, and its distribution among the ECOR strains is nonrandom. In two ECOR strains, the phage 21 int gene is interrupted by a 1,313-bp insertion element that has 99.3% nucleotide sequence identity with IS3411 of E. coli. The phylogenetic relationships of phage 21 strains derived from sequences of two different genomic regions were strongly incongruent, providing evidence of frequent recombination.     

Sequencing of Escherichia coli O111 O-antigen gene cluster and identification of O111-specific genes

Shiga toxin (Stx)-producing Escherichia coli strains of serogroup O111 are the most frequently isolated non-O157 strains causing outbreaks of gastroenteritis with hemolytic-uremic syndrome. The O111 O-antigen gene cluster had been cloned and about half of it has been sequenced; we have now sequenced the remainder of the gene cluster, which is 12.5 kb in length and which comprises 11 genes. On the basis of sequence similarity, we have identified all the O-antigen genes expected, including five sugar biosynthetic pathway genes, three transferase genes, the O-unit flippase gene, and the O-antigen polymerase gene. By PCR testing with E. coli strains representing all 166 O-antigen forms, some randomly selected gram-negative bacteria, and Salmonella enterica serovar Adelaide, we showed that four O-antigen genes are highly specific to O111. This work provides the basis for a sensitive test for the rapid detection of E. coli O111. This is important both for decisions related to patient care, because early treatment may reduce the risk of life-threatening complications, and for the detection of sources of contamination.     

The changing face of work in the United States: implications for individual, institutional, and societal survival

To study the identification and phylogeny of pathogenic isolates of Aspergillus, we designed primers from known cytochrome b amino acid sequences. Using these primers, 426 bp fragments of a mitochondrial (mt) cytochrome b gene were amplified by polymerase chain reaction (PCR), directly sequenced, and compared among Aspergillus fumigatus, A. flavus, A. niger, A. terreus and Emericella nidulans. Except for E. nidulans, all strains produced the 426 bp fragment by PCR. The E. nidulans strains demonstrated both an intron-presence fragment ( approximately 1500 bp) and intron-absence fragment (426 bp). Species-specific nucleotides were found in each of the five species. Based on sequence analysis, the strains were further divided into several groups within each species. When a 142-amino-acid sequence was estimated from the 426 bp nucleotide sequence using the yeast mt genetic code, the amino acid sequences showed no difference among strains of the individual species. DNA-based phylogenetic and amino acid-based trees were constructed. In conclusion, the DNA sequences of the cytochrome b gene may be of use in identification of pathogenic Aspergillus species and the amino acid-based tree suitable for discussing their phylogenetic relationships.     

Presence of a mitochondrial-type 70-kDa heat shock protein in Trichomonas vaginalis suggests a very early mitochondrial endosymbiosis in eukaryotes

Molecular phylogenetic analyses, based mainly on ribosomal RNA, show that three amitochondriate protist lineages, diplomonads, microsporidia, and trichomonads, emerge consistently at the base of the eukaryotic tree before groups having mitochondria. This suggests that these groups could have diverged before the mitochondrial endosymbiosis. Nevertheless, since all these organisms live in anaerobic environments, the absence of mitochondria might be due to secondary loss, as demonstrated for the later emerging eukaryote Entamoeba histolytica. We have now isolated from Trichomonas vaginalis a gene encoding a chaperone protein (HSP70) that in other lineages is addressed to the mitochondrial compartment. The phylogenetic reconstruction unambiguously located this HSP70 within a large set of mitochondrial sequences, itself a sister-group of alpha-purple bacteria. In addition, the T. vaginalis protein exhibits the GDAWV sequence signature, so far exclusively found in mitochondrial HSP70 and in proteobacterial dnaK. Thus mitochondrial endosymbiosis could have occurred earlier than previously assumed. The trichomonad double membrane-bounded organelles, the hydrogenosomes, could have evolved from mitochondria.     

Isolation of marine polycyclic aromatic hydrocarbon (PAH)-degrading Cycloclasticus strains from the Gulf of Mexico and comparison of their PAH degradation ability with that of puget sound Cycloclasticus strains

Phenanthrene- and naphthalene-degrading bacteria were isolated from four offshore and nearshore locations in the Gulf of Mexico by using a modified most-probable-number technique. The concentrations of these bacteria ranged from 10(2) to 10(6) cells per ml of wet surficial sediment in mildly contaminated and noncontaminated sediments. A total of 23 strains of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were obtained. Based on partial 16S ribosomal DNA sequences and phenotypic characteristics, these 23 strains are members of the genus Cycloclasticus. Three representatives were chosen for a complete phylogenetic analysis, which confirmed the close relationship of these isolates to type strain Cycloclasticus pugetii PS-1, which was isolated from Puget Sound. PAH substrate utilization tests which included high-molecular-weight PAHs revealed that these isolates had similar, broad substrate ranges which included naphthalene, substituted naphthalenes, phenanthrene, biphenyl, anthracene, acenaphthene, and fluorene. Degradation of pyrene and fluoranthene occurred only when the strains were incubated with phenanthrene. Two distinct partial PAH dioxygenase iron sulfur protein (ISP) gene sequences were PCR amplified from Puget Sound and Gulf of Mexico Cycloclasticus strains. Phylogenetic analyses of these sequences revealed that one ISP type is related to the bph type of ISP sequences, while the other ISP type is related to the nah type of ISP sequences. The predicted ISP amino acid sequences for the Gulf of Mexico and Puget Sound strains are identical, which supports the hypothesis that these geographically separated isolates are closely related phylogentically. Cycloclasticus species appear to be numerically important and widespread PAH-degrading bacteria in both Puget Sound and the Gulf of Mexico.     

Activation of an adenosine 3'',5''-cyclic monophosphate-dependent Cl- conductance in response to neurohormonal stimuli in mouse endometrial epithelial cells: the role of cystic fibrosis transmembrane conductance regulator

Nitrogen-fixing microbial populations in a Douglas fir forest on the western slope of the Oregon Cascade Mountain Range were analyzed. The complexity of the nifH gene pool (nifH is the marker gene which encodes nitrogenase reductase) was assessed by performing nested PCR with bulk DNA extracted from plant litter and soil. The restriction fragment length polymorphisms (RFLPs) of PCR products obtained from litter were reproducibly different than the RFLPs of PCR products obtained from the underlying soil. The characteristic differences were found during the entire sampling period between May and September. RFLP analyses of cloned nifH PCR products also revealed characteristic patterns for each sample type. Among 42 nifH clones obtained from a forest litter library nine different RFLP patterns were found, and among 64 nifH clones obtained from forest soil libraries 13 different patterns were found. Only two of the patterns were found in both the litter and the soil, indicating that there were major differences between the nitrogen-fixing microbial populations. A sequence analysis of clones representing the 20 distinct patterns revealed that 19 of the patterns had a proteobacterial origin. All of the nifH sequences obtained from the Douglas fir forest litter localized in a distinct phylogenetic cluster characterized by the nifH sequences of members of the genera Rhizobium, Sinorhizobium, and Azospirillum. The nifH sequences obtained from soil were found in two additional clusters, one characterized by sequences of members of the genera Bradyrhizobium, Azorhizobium, Herbaspirillum, and Thiobacillus and the other, represented by a single nifH clone, located between the gram-positive bacteria and the cyanobacteria. Our results revealed the distinctness of the nitrogen-fixing microbial populations in litter and soil in a Douglas fir forest; the differences may be related to special requirements for degradation and mineralization processes in the plant litter.     

Phylogeny and PCR-based classification of Wolbachia strains using wsp gene sequences

Wolbachia are a group of intracellular inherited bacteria that infect a wide range of arthropods. They are associated with a number of different reproductive phenotypes in their hosts, such as cytoplasmic incompatibility, parthenogenesis and feminization. While it is known that the bacterial strains responsible for these different host phenotypes form a single clade within the alpha-Proteobacteria, until now it has not been possible to resolve the evolutionary relationships between different Wolbachia strains. To address this issue we have cloned and sequenced a gene encoding a surface protein of Wolbachia (wsp) from a representative sample of 28 Wolbachia strains. The sequences from this gene were highly variable and could be used to resolve the phylogenetic relationships of different Wolbachia strains. Based on the sequence of the wsp gene from different Wolbachia isolates we propose that the Wolbachia pipientis clade be initially divided into 12 groups. As more sequence information becomes available we expect the number of such groups to increase. In addition, we present a method of Wolbachia classification based on the use of group-specific wsp polymerase chain reaction (PGR) primers which will allow Wolbachia isolates to be typed without the need to clone and sequence individual Wolbachia genes. This system should facilitate future studies investigating the distribution and biology of Wolbachia strains from large samples of different host species.     

PCR amplification of the fimA gene sequence of Salmonella typhimurium, a specific method for detection of Salmonella spp

The goal of this study was to evaluate the suitability of the fimA gene amplification by PCR as a specific method for detection of Salmonella strains. Salmonella typhimurium and other pathogenic members of the family Enterobacteriaceae produce morphologically and antigenically related, thin, aggregative, type 1 fimbriae. A single gene, fimA, encodes the major fimbrial unit. In order to obtain higher specificity, we have selected a series of primers internal to the fimA gene sequence and have developed a PCR method for detecting Salmonella strains. A collection of 376 strains of Salmonella comprising over 80 serovars, isolated from animals and humans in Canada, have been used to evaluate this PCR method. Forty non-Salmonella strains were also tested by the same procedure. Cultures were screened by inoculating a single colony of bacteria directly into a PCR mixture containing a pair of primers specific for the fimA gene. The specific PCR product is an 85-bp fragment which was visualized by polyacrylamide gel electrophoresis and ethidium bromide staining. All Salmonella strains gave positive results by the PCR. Feed and milk samples contaminated by Salmonella strains were also detected by this procedure. The detection of all Salmonella strains tested and the failure to amplify the fragment from non-Salmonella strains confirm that the fimA gene contains sequences unique to Salmonella strains and demonstrate that this gene is a suitable PCR target for detection of Salmonella strains in food samples.     

Molecular identification of Gemella species from three patients with endocarditis

Gemella morbillorum and Gemella haemolysans are opportunistic pathogens which cause endocarditis and other severe infections. We report on three patients with endocarditis, one with endocarditis caused by G. haemolysans and two with endocarditis caused by G. morbillorum. The paucity of reports concerning these bacteria is probably related to the difficulties associated with their identification. For example, one of the strains reported in this study was originally sent to our laboratory with a preliminary characterization as a short "gram-negative" coccobacillus, highlighting the specific problem associated with Gram staining of these bacteria. The usefulness of 16S rRNA gene amplification, partial sequencing, and comparison of the nucleotide sequence to those in databases when standard phenotypic identification schemes are not helpful is emphasized. We also suggest that the use of simple tests, such as testing susceptibility to vancomycin for gram-negative bacteria and colistin for gram-positive bacteria, could prevent misinterpretation of Gram staining in gram-variable bacteria such as Gemella spp.     

Gamma interferon augments macrophage activation by lipopolysaccharide by two distinct mechanisms, at the signal transduction level and via an autocrine mechanism involving tumor necrosis factor alpha and interleukin-1

Acanthamoebae are ubiquitous soil and water bactivores which may serve as amplification vehicles for a variety of pathogenic facultative bacteria and as hosts to other, presently uncultured bacterial endosymbionts. The spectrum of uncultured endosymbionts includes gram-negative rods and gram-variable cocci, the latter recently shown to be members of the Chlamydiales. We report here the isolation from corneal scrapings of two Acanthamoeba strains that harbor gram-negative rod endosymbionts that could not be cultured by standard techniques. These bacteria were phylogenetically characterized following amplification and sequencing of the near-full-length 16S rRNA gene. We used two fluorescently labelled oligonucleotide probes targeting signature regions within the retrieved sequences to detect these organisms in situ. Phylogenetic analyses demonstrated that they displayed 99.6% sequence similarity and formed an independent and well-separated lineage within the Rickettsiales branch of the alpha subdivision of the Proteobacteria. Nearest relatives included members of the genus Rickettsia, with sequence similarities of approximately 85 to 86%, suggesting that these symbionts are representatives of a new genus and, perhaps, family. Distance matrix, parsimony, and maximum-likelihood tree-generating methods all consistently supported deep branching of the 16S rDNA sequences within the Rickettsiales. The oligonucleotide probes displayed at least three mismatches to all other available 16S rDNA sequences, and they both readily permitted the unambiguous detection of rod-shaped bacteria within intact acanthamoebae by confocal laser-scanning microscopy. Considering the long-standing relationship of most Rickettsiales with arthropods, the finding of a related lineage of endosymbionts in protozoan hosts was unexpected and may have implications for the preadaptation and/or recruitment of rickettsia-like bacteria to metazoan hosts.     

Molecular evolutionary analysis of the thiamine-diphosphate-dependent enzyme, transketolase

Members of the transketolase group of thiamine-diphosphate-dependent enzymes from 17 different organisms including mammals, yeast, bacteria, and plants have been used for phylogenetic reconstruction. Alignment of the amino acid and DNA sequences for 21 transketolase enzymes and one putative transketolase reveals a number of highly conserved regions and invariant residues that are of predicted importance for enzyme activity, based on the crystal structure of yeast transketolase. One particular sequence of 36 residues has some similarities to the nucleotide-binding motif and we designate it as the transketolase motif. We report further evidence that the recP protein from Streptococcus pneumoniae might be a transketolase and we list a number of invariant residues which might be involved in substrate binding. Phylogenies derived from the nucleotide and the amino acid sequences by various methods show a conventional clustering for mammalian, plant, and gram-negative bacterial transketolases. The branching order of the gram-positive bacteria could not be inferred reliably. The formaldehyde transketolase (sometimes known as dihydroxyacetone synthase) of the yeast Hansenula polymorpha appears to be orthologous to the mammalian enzymes but paralogous to the other yeast transketolases. The occurrence of more than one transketolase gene in some organisms is consistent with several gene duplications. The high degree of similarity in functionally important residues and the fact that the same kinetic mechanism is applicable to all characterized transketolase enzymes is consistent with the proposition that they are all derived from one common ancestral gene. Transketolase appears to be an ancient enzyme that has evolved slowly and might serve as a model for a molecular clock, at least within the mammalian clade.     

Protein phylogenies and signature sequences: A reappraisal of evolutionary relationships among archaebacteria, eubacteria, and eukaryotes

The presence of shared conserved insertion or deletions (indels) in protein sequences is a special type of signature sequence that shows considerable promise for phylogenetic inference. An alternative model of microbial evolution based on the use of indels of conserved proteins and the morphological features of prokaryotic organisms is proposed. In this model, extant archaebacteria and gram-positive bacteria, which have a simple, single-layered cell wall structure, are termed monoderm prokaryotes. They are believed to be descended from the most primitive organisms. Evidence from indels supports the view that the archaebacteria probably evolved from gram-positive bacteria, and I suggest that this evolution occurred in response to antibiotic selection pressures. Evidence is presented that diderm prokaryotes (i.e., gram-negative bacteria), which have a bilayered cell wall, are derived from monoderm prokaryotes. Signature sequences in different proteins provide a means to define a number of different taxa within prokaryotes (namely, low G+C and high G+C gram-positive, Deinococcus-Thermus, cyanobacteria, chlamydia-cytophaga related, and two different groups of Proteobacteria) and to indicate how they evolved from a common ancestor. Based on phylogenetic information from indels in different protein sequences, it is hypothesized that all eukaryotes, including amitochondriate and aplastidic organisms, received major gene contributions from both an archaebacterium and a gram-negative eubacterium. In this model, the ancestral eukaryotic cell is a chimera that resulted from a unique fusion event between the two separate groups of prokaryotes followed by integration of their genomes.     

16S rRNA gene sequence of Rubrobacter radiotolerans and its phylogenetic alignment with members of the genus Arthrobacter, gram-positive bacteria, and members of the family Deinococcaceae

The nearly complete sequence of the 16S rRNA gene of an extremely highly radiotolerant bacterium, Rubrobacter radiotolerans (reclassified from Arthrobacter radiotolerans based on chemical characteristics), was determined by PCR amplification of the genomic DNA followed by cloning of the amplified gene and sequencing by the dideoxynucleotide method. The sequence was aligned with the sequences of members of the genus Arthrobacter and also with the sequences of representatives of the gram-positive bacteria having high G + C contents and the family Deinococcaceae (radioresistant micrococci and their relatives). The results of our phylogenetic analysis confirmed that R. radiotolerans is not a member of the Arthrobacter group and thus supported the previous reclassification. Moreover, although it is radioresistant and has a high G+C content, R. radiotolerans is more closely related to the gram-positive bacteria with high G+C contents than to the radioresistant members of the Deinococcaceae.     

The flagellin gene of Borrelia miyamotoi sp. nov. and its phylogenetic relationship among Borrelia species

We have cloned and sequenced the flagellin gene from Borrelia miyamotoi strain HT31 and compared it with previously published flagellin sequences. Sequence similarity analysis demonstrated that strain HT31 is phylogenetically distant from the three species of Lyme disease borreliae is deeply branched into the relapsing fever borrelia cluster. The result was in full agreement with the classification of Borrelia strains using 16S tRNA sequences. This finding indicates that a phylogenetic analysis using flagellin gene sequences might be useful for classification of Borrelia strains.     

Follicular vascularity--the predictive value of transvaginal power Doppler ultrasonography in an in-vitro fertilization programme: a preliminary study

The glnA gene from the human pathogen Streptococcus agalactiae was cloned from a genomic library prepared with the lambda phage vector lambdaDASHII. A 4.6-kb DNA fragment of one of the recombinant phages was subcloned in pUC18. This Escherichia coli clone expressed a 52-kDa protein encoded by a 1,341-bp open reading frame. The nucleotide sequence of the open reading frame and the deduced amino acid sequence shared a significant degree of homology with the sequences of other glutamine synthetases (GS). The highest homology was between our deduced protein and GS of gram-positive bacteria such as Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus. Plasmids with the cloned streptococcal glnA were able to complement E. coli glnA mutants grown on minimal media. Rabbit antisera to streptococcal GS recombinant protein recognized not only the recombinant protein but also a similar-sized band in mutanolysin extracts of all group B streptococcal strains tested, regardless of polysaccharide type or surface protein profile. The amino acid sequence of the deduced protein had similarities to other streptococcal cell-surface-bound proteins. The possible functional role of the immunological features of streptococcal GS is discussed.