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PBP1 Is a Component of the Bacillus subtilis Cell Division Machinery. Dirk-Jan Scheffers, 2004.Bacillus subtilis penicillin-binding protein PBP1 has been implicated in cell division . We show here that a PBP1 knockout strain is affected in the formation of the asymmetric sporulation septum and that green fluorescent protein-PBP1 localizes to the sporulation septum . Localization of PBP1 to the vegetative septum is dependent on various cell division proteins . This study proves that PBP1 forms part of the B . subtilis cell division machinery . Phylogeny and Functional Expression of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from the Autotrophic Ammonia-Oxidizing Bacterium Nitrosospira sp.Isolate 40KI. Janne B. Utåker, 2002.The autotrophic ammonia-oxidizing bacteria (AOB), which play an important role in the global nitrogen cycle, assimilate CO2 by using ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) . Here we describe the first detailed study of RubisCO (cbb) genes and proteins from the AOB . The cbbLS genes from Nitrosospira sp . isolate 40KI were cloned and sequenced . Partial sequences of the RubisCO large subunit (CbbL) from 13 other AOB belonging to the ß and  subgroups of the class Proteobacteria are also presented . All except one of the ß-subgroup AOB possessed a red-like type I RubisCO with high sequence similarity to the Ralstonia eutropha enzyme . All of these new red-like RubisCOs had a unique six-amino-acid insert in CbbL . Two of the AOB, Nitrosococcus halophilus Nc4 and Nitrosomonas europaea Nm50, had a green-like RubisCO . With one exception, the phylogeny of the AOB CbbL was very similar to that of the 16S rRNA gene . The presence of a green-like RubisCO in N . europaea was surprising, as all of the other ß-subgroup AOB had red-like RubisCOs . The green-like enzyme of N . europaea Nm50 was probably acquired by horizontal gene transfer . Functional expression of Nitrosospira sp . isolate 40KI RubisCO in the chemoautotrophic host R . eutropha was demonstrated . Use of an expression vector harboring the R . eutropha cbb control region allowed regulated expression of Nitrosospira sp . isolate 40KI RubisCO in an R . eutropha cbb deletion strain . The Nitrosospira RubisCO supported autotrophic growth of R . eutropha with a doubling time of 4.6 h . This expression system may allow further functional analysis of AOB cbb genes .
CheZ Phosphatase Localizes to Chemoreceptor Patches via CheA-Short. Brian J. Cantwell, 2003.We have investigated the conditions required for polar localization of the CheZ phosphatase by using a CheZ-green fluorescent protein fusion protein that, when expressed from a single gene in the chromosome, restored chemotaxis to a  cheZ strain . Localization was observed in wild-type,
cheZ,
cheYZ, and
cheRB cells but not in cells with cheA, cheW, or all chemoreceptor genes except aer deleted . Cells making only CheA-short (CheAS) or CheA lacking the P2 domain also retained normal localization, whereas cells producing only CheA-long or CheA missing the P1 and P2 domains did not . We conclude that CheZ localization requires the truncated C-terminal portion of the P1 domain present in CheAS . Missense mutations targeting residues 83 through 120 of CheZ also abolished localization . Two of these mutations do not disrupt chemotaxis, indicating that they specifically prevent interaction with CheAS while leaving other activities of CheZ intact .
Alternative Splicing of Transcripts from crtI and crtYB Genes of Xanthophyllomyces dendrorhous. P. Lodato, 2003.Xanthophyllomyces dendrorhous is one of the relevant sources of the carotenoid astaxanthin . In this paper, we describe for the first time cloning of unexpected cDNAs obtained from the crtI and crtYB genes of X . dendrorhous strain UCD 67-385 . The cDNA of the crtI gene conserves 80 bp of the first intron, while the cDNA of the crtYB gene conserves 55 bp of the first intron and lacks 111 bp of the second exon . The crtI and crtYB RNAs could be spliced in alternative splice sites, which produced alternative transcripts which could not be translated to active CRTI and CRTYB proteins since they had numerous stop codons in their sequences . The ratio of mature mRNA to alternative mRNA for the crtI gene decreased as a function of the age of the culture, while the cellular content of carotenoids increased . It is possible that splicing to mature or alternative transcripts could regulate the cellular concentrations of phytoene desaturase and phytoene synthase-lycopene cyclase proteins, depending on the physiological or environmental conditions .
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