Importance of the galE gene on the virulence of Pasteurella multocida

The galE gene of Pasteurella multocida has been isolated by complementing galE-defective mutants of Salmonella typhimurium with a plasmid library of this organism. The complete nucleotide sequence of the P. multocida galE gene consists of 1017 nucleotides, encoding a predicted polypeptide of 339 amino acids. The deduced amino acid sequence displayed the highest identity (85%) to the GalE protein of Haemophilus influenzae. However, the gene organization surrounding the galE locus was different from that of H. influenzae. A galE-defective mutant of P. multocida was obtained by replacement of the active galE gene by a copy inactivated in vitro. The resulting galE mutant was highly attenuated as seen in a biological test carried out in a mouse model.     

Regulation of the regulatory gene for the arabinose pathway,araC

The promoter of the araC gene was fused to the structural genes of the lac operon using the techniques described in the preceding paper. The resulting fusion strains were used to study the regulation of the araC gene by assaying the fused lac gene products. It was found that the expression of the fused lac genes was repressed by the product of the araC gene and was regulated by the cyclic AMP catabolite control system. This implies that the araC gene itself is repressed by its own product and is catabolite regulated. These findings introduce a new level of complexity in the regulation of the arabinose pathway of Escherichia coli.     

Studies on the substrate specificity of the T 4 excision repair endonuclease

Previous studies have shown that the v gene of bacteriophage T4 codes for an endonuclease that specifically attacks pyrimidine dimer sites in UV-irradiated DNA. The present studies have examined the role of this endonuclease in the repair of DNA damaged by nitrogen mustard, N-methyl-N′-nitro-N-nitrosoguanidine (NTG), mitomycin C and 4-nitroquinoline-N-oxide. The observation by Harm that the v gene product of phage T4 facilitates repair of UV damage to the host DNA of excision-repair defective strains enabled us to test whether it does the same with other cellular DNA lesions. It was shown that infection of UV-irradiated E. coliB_s−1 with UV-inactivated phage T4v+ resulted in rescue of a certain fraction of the host cells. However no v gene mediated repair E. coli B_s−1 was observed following treatment with the chemical agents mentioned. Furthermore, though phage T4v₁ is more sensitive to UV-irradiation than phage T4, there was no observed difference in the sensitivity of these phages to nitrogen mustard or NTG. On the basis of these observations it was concluded that the v gene coded endonuclease of T4 is specific for the excision repair of pyrimidine dimers and does not participate in the repair of chemically damaged DNA. In vitro enzymatic degradation of DNA alkylated with nitrogen mustard was observed, but it is probable that this degradation is not part of a repair reaction in vivo.     

Genotypes of the vitamin D-binding protein gene in patients with chronic obstructive pulmonary disease and in the healthy population of the Republic Bashkortostan

Allele and genotype frequency distributions of the vitamin D-binding protein gene (DBP) were studied in patients with chronic obstructive pulmonary disease (COPD, N = 298) and healthy individuals (N = 237) from two ethnic groups (Tatars and Russians) resident in the Republic Bashkortostan. The DBP genotype frequency distribution significantly differed between Tatars and Russians (X ² = 8.854, df = 5, P = 0.04). The DBP allele frequency distribution was similar in healthy subjects of both ethnic groups, with allele frequency decreasing as GC*1S > GC*1F > GC*2. The most common DBP genotype was GC*1F/1S in Tatars (36.79%) and GC*1S/2 in Russians (34.62%). It was demonstrated that, in Tatars, the genotype GC*1F/1S is protective against COPD, its frequency being significantly lower in COPD patients than in healthy subjects (19.85% vs. 36.79%; X ² = 7.622, P = 0.0067, P _cor = 0.0335; OR = 0.42, 95%CI 0.42–0.95). On the other hand, the genotype GC*1F/2 was more common among COPD patients than among healthy individuals (19.08% vs. 8.49%; X ² = 4.52, P = 0.033, P _cor = 0.165; OR = 2.54, 95%CI 1.067–6.20). No differences in DBP genotype and allele frequency distributions was found between COPD patients and healthy individuals in the Russian population.     

Comparative analysis of the karyotype of the sculpin Myoxocephalus ochotensis (Pisces: Cottidae) from the Odyan Bay of the Sea of Okhotsk

The karyotype of the endemic Okhotsk Sea sculpin Myoxocephalus ochotensis Schmidt (Cottidae) from Odyan Bay was studied. The number and morphology of chromosomes were determined, 2n = 42 (2 metacentric, 20 subtelocentric, and 20 acrocentric chromosomes), NF = 44. Variability of chromosome number was not revealed; no difference between male and female karyotypes was found. The karyotype of the Okhotsk sculpin M. ochotensis was compared with karyotypes of the Far East Steller’s M. stelleri (Tilesius), snow M. brandti (Steindachner), and plain M. jaok (Cuvier) sculpins, and to the European shorthorn sculpin M. scorpius (Linnaeus) from White Sea. Their similarities and distinctions were shown.     

Studies of the transmissibility of the agent of bovine spongiform encephalopathy to the domestic chicken

Background

Escherichia coli O157:H7 is the most common serovar of enterohemorrhagic E. coli associated with serious human disease outbreaks. Cattle are the main reservoir with E. coli O157:H7 inducing hemorrhagic enteritis in persistent shedding beef cattle, however little is known about how this pathogen affects cattle health. Jejunal Hemorrhage Syndrome (JHS) has unclear etiology but the pathology is similar to that described for E. coli O157:H7 challenged beef cattle suggestive that E. coli O157:H7 could be involved. There are no effective treatments for JHS however new approaches to managing pathogen issues in livestock using prebiotics and probiotics are gaining support. The first objective of the current study was to characterize pathogen colonization in hemorrhaged jejunum of dairy cattle during natural JHS outbreaks. The second objective was to confirm the association of mycotoxigenic fungi in feeds with the development of JHS and also to identify the presence of potential mycotoxins. The third objective was to determine the impact of a prebiotic, Celmanax?, or probiotic, Dairyman's Choice? paste, on the cytotoxicity associated with feed extracts in vitro. The fourth objective was to determine the impact of a prebiotic or a probiotic on E. coli O157:H7 colonization of mucosal explants and a bovine colonic cell line in vitro. The final objective was to determine if prebiotic and probiotic feed additives could modify the symptoms that preceded JHS losses and the development of new JHS cases.

Findings

Dairy cattle developed JHS after consuming feed containing several types of mycotoxigenic fungi including Fusarium culmorum, F. poae, F. verticillioides, F. sporotrichioides, Aspergillus flavus, Penicillium roqueforti, P. crustosum, P. paneum and P. citrinum. Mixtures of Shiga toxin - producing Escherichia coli (STEC) colonized the mucosa in the hemorrhaged tissues of the cattle and no other pathogen was identified. The STECs expressed Stx1 and Stx2, but more significantly, Stxs were also present in the blood clot blocking the jejunum. Mycotoxin analysis of the corn crop confirmed the presence of fumonisin, NIV, ZEAR, DON, 15-ADON, 3-ADON, NEO, DAS, HT-2 and T-2. Feed extracts were toxic to enterocytes and 0.1% Celmanax? removed the cytotoxicity in vitro. There was no effect of Dairyman's Choice? paste on feed-extract activity in vitro. Fumonisin, T-2, ZEAR and DON were toxic to bovine cells and 0.1% Celmanax? removed the cytotoxicity in vitro. Celmanax? also directly decreased E. coli O157:H7 colonization of mucosal explants and a colonic cell line in a dose-dependent manner. There was no effect of Dairyman's Choice? paste on E. coli O157:H7 colonization in vitro. The inclusion of the prebiotic and probiotic in the feed was associated with a decline in disease.

Conclusion

The current study confirmed an association between mycotoxigenic fungi in the feed and the development of JHS in cattle. This association was further expanded to include mycotoxins in the feed and mixtures of STECs colonizing the severely hemorrhaged tissues. Future studies should examine the extent of involvement of the different STEC in the infection process. The prebiotic, Celmanax?, acted as an anti-adhesive for STEC colonization and a mycotoxin binder in vitro. Future studies should determine the extent of involvement of the prebiotic in altering disease.     

Cloning and characteristics of the antibacterial peptide gene abaecin in the bumblebee Bombus lantschouensis (Hymenoptera: Apidae)

Among the antimicrobial peptides, abaecin is rich in proline content and plays a vital role in insect innate immune defense. Here, the full-length gene of abaecin from the bumblebee Bombus lantschouensis was cloned, and its expression profiles for different tissues, developmental stages and reproductive statuses were analyzed by RT-qPCR. Meanwhile, the responses of abaecin to a bacterium (Escherichia coli) and a fungus (Beauveria bassiana) were tested. The full length of abaecin cDNA was 470 bp, and the open reading frame (ORF) was 258 bp, encoding a polypeptide of 85 amino acids. The abaecin gene consists of three exons and two introns. Phylogenetic analysis showed that Bombus ignitus was the closest species to B. lantschouensis base on putative Abaecin protein sequence. Expression analysis showed that abaecin was expressed broadly in different tissues, with the highest expression in fat bodies and extremely low expression in antennae. Regarding developmental stage, low expression of abacein was detected in eggs and larvae, and high expression was detected in pupal stages. The highest expression was observed at the Pw pupal stage (pupae with an unpigmented body cuticle and white eyes), and the expression then decreased from the Pp (pupae with pink eyes) to the Pdd (dark-eye pupae with a dark-pigmented cuticle) stages. In addition, the expression of abaecin was higher in egg-laying than in non-egg-laying female bumblebees. Both E. coli and B. bassiana infections induced the expression of abaecin. Our results indicated that the abaecin gene plays important roles in the development, reproduction and immune responses of bumblebees. During the artificial rearing of bumblebees, a good environment should be created to avoid infection with bacteria or fungi.     

Characterization of the transacylase activity of rat liver 60-kDa lysophospholipase-transacylase. Acyl transfer from the sn-2 to the sn-1 position

Rat liver 60-kDa lysophospholipase-transacylase catalyzes not only the hydrolysis of 1-acyl-sn-glycero-3-phosphocholine, but also the transfer of its acyl chain to a second molecule of 1-acyl-sn-glycero-3-phosphocholine to form phosphatidylcholine (H. Sugimoto, S. Yamashita, J. Biol. Chem. 269 (1994) 6252–6258). Here we report the detailed characterization of the transacylase activity of the enzyme. The enzyme mediated three types of acyl transfer between donor and acceptor lipids, transferring acyl residues from: (1) the sn-1 to -1(3); (2) sn-1 to -2; and (3) sn-2 to -1 positions. In the sn-1 to -1(3) transfer, the sn-1 acyl residue of 1-acyl-sn-glycero-3-phosphocholine was transferred to the sn-1(3) positions of glycerol and 2-acyl-sn-glycerol, producing 1(3)-acyl-sn-glycerol and 1,2-diacyl-sn-glycerol, respectively. In the sn-1 to -2 transfer, the sn-1 acyl residue of 1-acyl-sn-glycero-3-phosphocholine was transferred to not only the sn-2 positions of 1-acyl-sn-glycero-3-phosphocholine, but also 1-acyl-sn-glycero-3-phosphoethanolamine, producing phosphatidylcholine and phosphatidylethanolamine, respectively. 1-Acyl-sn-glycero-3-phospho-myo-inositol and 1-acyl-sn-glycero-3-phosphoserine were much less effectively transacylated by the enzyme. In the sn-2 to -1 transfer, the sn-2 acyl residue of 2-acyl-sn-glycero-3-phosphocholine was transferred to the sn-1 position of 2-acyl-sn-glycero-3-phosphocholine and 2-acyl-sn-glycero-3-phosphoethanolamine, producing phosphatidylcholine and phosphatidylethanolamine, respectively. Consistently, the enzyme hydrolyzed the sn-2 acyl residue from 2-acyl-sn-glycero-3-phosphocholine. By the sn-2 to -1 transfer activity, arachidonic acid was transferred from the sn-2 position of donor lipids to the sn-1 position of acceptor lipids, thus producing 1-arachidonoyl phosphatidylcholine. When 2-arachidonoyl-sn-glycero-3-phosphocholine was used as the sole substrate, diarachidonoyl phosphatidylcholine was synthesized at a rate of 0.23 μmol/min/mg protein. Thus, 60-kDa lysophospholipase-transacylase may play a role in the synthesis of 1-arachidonoyl phosphatidylcholine needed for important cell functions, such as anandamide synthesis.     

Allelopathic effects of the dinophyte Prorocentrum minimum on the growth of the bacillariophyte Skeletonema costatum

We investigated growth interactions between the dinophyte Prorocentrum minimum and the bacillariophyte Skeletonema costatum using bi-algal cultures under axenic conditions. When low cell densities of P. minimum and high cell densities of S. costatum were inoculated into the same medium, growth of P. minimum was suppressed. Other inoculum combinations resulted in reduced S. costatum maximum cell densities. A mathematical model was used to simulate growth and interactions of P. minimum and S. costatum in bi-algal cultures. The model indicated that P. minimum always outcompeted S. costatum over time. Enriched filtrate from low-density P. minimum cultures significantly stimulated S. costatum growth, but enriched filtrate from high-density P. minimum cultures notably inhibited the growth of S. costatum. Growth of P. minimum was not affected by enriched filtrate from cultures of P. minimum at any density. Filtrates of P. minimum cultures were fractionated by ultrafiltration (molecular weight cutoff >3000 Da), and retentate that included polysaccharide(s) significantly inhibited the growth of S. costatum.     

Stress and salicylic acid induce the expression of PnFT2 in the regulation of the stress-induced flowering of Pharbitis nil

Poor nutrition and low temperature stress treatments induced flowering in the Japanese morning glory Pharbitis nil (synonym Ipomoea nil) cv. Violet. The expression of PnFT2, one of two homologs of the floral pathway integrator gene FLOWERING LOCUS T (FT), was induced by stress, whereas the expression of both PnFT1 and PnFT2 was induced by a short-day treatment. There was no positive correlation between the flowering response and the homolog expression of another floral pathway integrator gene SUPPRESSOR OF OVEREXPRESSION OF CO1 and genes upstream of PnFT, such as CONSTANS. In another cultivar, Tendan, flowering and PnFT2 expression were not induced by poor nutrition stress. Aminooxyacetic acid (AOA), a phenylalanine ammonia-lyase inhibitor, inhibited the flowering and PnFT2 expression induced by poor nutrition stress in Violet. Salicylic acid (SA) eliminated the inhibitory effects of AOA. SA enhanced PnFT2 expression under the poor nutrition stress but not under non-stress conditions. These results suggest that SA induces PnFT2 expression, which in turn induces flowering; SA on its own, however, may not be sufficient for induction.     

Tylenchulus semipenetrans Alters the Microbial Community in the Citrus Rhizosphere

Infection of citrus seedlings by Tylenchulus semipenetrans was shown to reduce subsequent infection of roots by Phytophthora nicotianae and to increase plant growth compared to plants infected by only the fungus. Hypothetical mechanisms by which the nematode suppresses fungal development include nutrient competition, direct antibiosis, or alteration of the microbial community in the rhizosphere to favor microorganisms antagonistic to P. nicotianae. A test of the last hypothesis was conducted via surveys of five sites in each of three citrus orchards infested with both organisms. A total of 180 2-cm-long fibrous root segments, half with a female T. semipenetrans egg mass on the root surface and half without, were obtained from each orchard site. The samples were macerated in water, and fungi and bacteria in the suspensions were isolated, quantified, and identified. No differences were detected in the numbers of microorganism species isolated from nematode-infected and uninfected root segments. However, nematode-infected root segments had significantly more propagules of bacteria at all orchard sites. Bacillus megaterium and Burkholderia cepacia were the dominant bacterial species recovered. Bacteria belonging to the genera Arthrobacter and Stenotrophomonas were encountered less frequently. The fungus community was dominated by Fusarium solani, but Trichoderma, Verticillum, Phythophthora, and Penicillium spp. also were recovered. All isolated bacteria equally inhibited the growth of P. nicotianae in vitro. Experiments using selected bacteria, T. semipenetrans, and P. nicotianae, alone or in combination, were conducted in both the laboratory and greenhouse. Root and stem fresh weights of P. nicotianae-infected plants treated with T. semipenetrans, B. cepacia, or B. megaterium were greater than for plants treated only with the fungus. Phytophthora nicotianae protein in roots of fungus-infected plants was reduced by nematodes (P ≤ 0.001), either alone or in combination with either bacterium. However, treatment with bacteria did not affect P. nicotianae development in roots. The results suggest different mechanisms by which T. semipenetrans, B. cepacia, and B. megaterium may mitigate virulence of P. nicotianae.     

Role of the parCBA Operon of the Broad-Host-Range Plasmid RK2 in Stable Plasmid Maintenance

The par region of the stably maintained broad-host-range plasmid RK2 is organized as two divergent operons, parCBA and parDE, and a cis-acting site. parDE encodes a postsegregational killing system, and parCBA encodes a resolvase (ParA), a nuclease (ParB), and a protein of unknown function (ParC). The present study was undertaken to further delineate the role of the parCBA region in the stable maintenance of RK2 by first introducing precise deletions in the three genes and then assessing the abilities of the different constructs to stabilize RK2 in three strains of Escherichia coli and two strains of Pseudomonas aeruginosa. The intact parCBA operon was effective in stabilizing a conjugation-defective RK2 derivative in E. coli MC1061K and RR1 but was relatively ineffective in E. coli MV10Δlac. In the two strains in which the parCBA operon was effective, deletions in parB, parC, or both parB and parC caused an approximately twofold reduction in the stabilizing ability of the operon, while a deletion in the parA gene resulted in a much greater loss of parCBA activity. For P. aeruginosa PAO1161Rif^r, the parCBA operon provided little if any plasmid stability, but for P. aeruginosa PAC452Rif^r, the RK2 plasmid was stabilized to a substantial extent by parCBA. With this latter strain, parA and res alone were sufficient for stabilization. The cer resolvase system of plasmid ColE1 and the loxP/Cre system of plasmid P1 were tested in comparison with the parCBA operon. We found that, not unlike what was previously observed with MC1061K, cer failed to stabilize the RK2 plasmid with par deletions in strain MV10Δlac, but this multimer resolution system was effective in stabilizing the plasmid in strain RR1. The loxP/Cre system, on the other hand, was very effective in stabilizing the plasmid in all three E. coli strains. These observations indicate that the parA gene, along with its res site, exhibits a significant level of plasmid stabilization in the absence of the parC and parB genes but that in at least one E. coli strain, all three genes are required for maximum stabilization. It cannot be determined from these results whether or not the stabilization effects seen with parCBA or the cer and loxP/Cre systems are strictly due to a reduction in the level of RK2 dimers and an increase in the number of plasmid monomer units or if these systems play a role in a more complex process of plasmid stabilization that requires as an essential step the resolution of plasmid dimers.     

Anatomical description of the renal arteries and veins in the European rabbit

The aim of this study was to describe origin, localisation and variations of renal arteries and veins in the rabbit. The study was carried out on 40 adult European rabbits. We prepared corrosion casts of the rabbit arterial and venous system. Spofacryl was used as the casting medium. In 75% of cases the origin of arteriae renales was located at the level of the third lumbar vertebra and in remaining 25% of cases arteria renalis dextra branched off at the level of the second lumbar vertebra. In 10% of cases we observed that the number of arteria renalis sinistra was doubled. We recorded also in one case the presence of arteria renalis accessoria for ren dexter. In 10% of cases we observed that the number of vena renalis sinistra was doubled. In 5% of cases two venae renales sinistrae arose from the kidney and subsequently, about 1 cm from opening to vena cava caudalis, they united to form a single vein. In 5% of cases two venae renales sinistrae arose from the kidney and subsequently, approximately 1 cm away from hilus renalis, they united. The obtained variations of the number of renal arteries were partially homologous to the human, but variations of renal veins were localized on the other side as in human.     

Characterization of the trnL-trnF spacer sequence of the chloroplast tRNA genes in Spirodela species

The trnL-trnF spacer region of the chloroplast tRNA genes was sequenced and characterized in 14 accessions of the genus Spirodela (Lemnaceae). Only a low intraspecific variation of the spacer was observed in geographically isolated and morphologically different accessions of S. polyrrhiza, the most widespread Spirodela species. Five haplotypes of the spacer were identified, differing in mono-and oligonucleotide repeats and extended indels, specific to S. polyrrhiza, Landoltia punctata, and Lemna sp. The result supported the isolation of Landoltia from Spirodela.     

Molecular analysis of the chromosomal region encoding the nifA and nifB genes of Acetobacter diazotrophicus

The Acetobacter diazotrophicus nifA gene was isolated by its ability to restore a Nif⁺ phenotype to a nifA mutant of Azotobacter vinelandii. Sequencing revealed that the nifA gene was upstream and adjacent to the nifB gene and both are transcribed in the same direction but independently from different promoters. The 3′ end of the nifB gene was located approximately 2.5 kb upstream of the nitrogenase structural gene cluster, nifHDK. The deduced amino acid sequences of the A. diazotrophicus nifA and nifB gene products were most similar to the NifA and NifB proteins of Azorhizobium caulinodans and Rhodobacter capsulatus, respectively. A. diazotrophicus nifA expression was repressed in cultures exposed to high levels of ammonium while oxygen apparently had no influence. Both oxygen and ammonium prevented expression of a nifB-reporter strain, consistent with the observation that ammonium repressed nifA expression, and indicating that A. diazotrophicus NifA activity is inhibited by oxygen as in other Proteobacterial α group diazotrophs.     

Studies on the developmental pattern of the enzymes converting glucose 6-phosphate to myo-inositol in the rat

The myo-inositol level of plasma was determined during pre- and postnatal development of the rat. Fetal concentrations exceeded those of maternal rats by nearly 10-fold. Immediately after birth, the myo-inositol level decreased but was maintained at values 3–4 times that of the lactating dams. The cyclitol content of rat milk was high and rose during lactation to a maximum of 1.6 mM.The biosynthesis of myo-inositol from glucose 6-phosphate is catalyzed by glucose 6-phosphate:l-myo-inositol-1-phosphate cyclase and l-myo-inositol-1-phosphate phosphatase. The activity of both enzymes was monitored in fetal and neonatal liver, maternal liver, placenta, and mammary gland. Results indicated that the fetal liver accounted for over 48% of the total carcass cyclase and 26% of the total carcass phosphatase activity. Developmental changes correlated well with the pattern of myo-inositol in fetal rat plasma. Similarly, the enzymes of the myo-inositol biosynthetic pathway increased in rat mammary gland in close agreement with the myo-inositol content of milk and diminished to prelactation activities within 24 hr after the onset of involution.The myo-inositol level of colostrum and milk of five human subjects was highest (2.8 mM) before birth and decreased to 40% of that level 5 days postpartum, where it remained for at least 3 weeks. Even after 7 months of lactation, the milk of one subject contained 3–4-fold more myo-inositol than all commercial infant formulas analyzed.     

Expanding the Cyanuric Acid Hydrolase Protein Family to the Fungal Kingdom

The known enzymes that open the s-triazine ring, the cyanuric acid hydrolases, have been confined almost exclusively to the kingdom Bacteria and are all homologous members of the rare cyanuric acid hydrolase/barbiturase protein family. In the present study, a filamentous fungus, Sarocladium sp. strain CA, was isolated from soil by enrichment culturing using cyanuric acid as the sole source of nitrogen. A reverse-genetic approach identified a fungal cyanuric acid hydrolase gene composed of two exons and one intron. The translated spliced sequence was 39 to 53% identical to previously characterized bacterial cyanuric acid hydrolases. The sequence was used to generate a gene optimized for expression in Escherichia coli and encoding an N-terminally histidine-tagged protein. The protein was purified by nickel affinity and anion-exchange chromatography. The purified protein was shown by ¹³C nuclear magnetic resonance (¹³C-NMR) to produce carboxybiuret as the product, which spontaneously decarboxylated to yield biuret and carbon dioxide. The protein was very narrow in substrate specificity, showing activity only with cyanuric acid and N-methyl cyanuric acid. Barbituric acid was an inhibitor of enzyme activity. Sequence analysis identified genes with introns in other fungi from the Ascomycota that, if spliced, are predicted to encode proteins with cyanuric acid hydrolase activity. The Ascomycota cyanuric acid hydrolase homologs are most closely related to cyanuric acid hydrolases from Actinobacteria.     

Effect of the aeration mode and yeast extract on the oxidation of high-pyrrhotite sulfide ore flotation concentrate and on the composition of the acidophilic chemolithotrophic microbial community

Optimal aeration conditions were determined and the effect of yeast extract on biooxidation of high-pyrrhotite sulfide ore flotation concentrate in the course of continuous cultivation of an acidophilic chemolithotrophic microbial community was studied in a line of four sequential laboratory reactors; the aeration rate was 3 L/(L min), yeast extract concentration was 0.02%. The gold recovery level was 96.45% at 2.23% elemental sulfur content in the solid residue. The dominant strains identified in the community responsible for biooxidation were Acidithiobacillus caldus OL13-1, At. caldus OL13-3 = At. caldus OL12-3, and an ‘Acidiferrobacter’ strain. Strains Sulfobacillus thermosulfidooxidans OL13-2 = S. thermosulfidooxidans OL12-1 and Ferroplasma acidiphilum OL13-4 = F. acidiphilum OL12-4 were isolated in pure culture and identified.