Evidence for an ancient chromosomal duplication in Arabidopsis thaliana by sequencing and analyzing a 400-kb contig at the APETALA2 locus on chromosome 4

As part of the European Scientists Sequencing Arabidopsis program, a contiguous region (396607 bp) located on chromosome 4 around the APETALA2 gene was sequenced. Analysis of the sequence and comparison to public databases predicts 103 genes in this area, which represents a gene density of one gene per 3.85 kb. Almost half of the genes show no significant homology to known database entries. In addition, the first 45 kb of the contig, which covers 11 genes, is similar to a region on chromosome 2, as far as coding sequences are concerned. This observation indicates that ancient duplications of large pieces of DNA have occurred in Arabidopsis.     

Response of Three Arbuscular Mycorrhizal Fungi to Simulated Acid Rain and Aluminium Stress

Simulated acid rain (SAR) combined with higher concentration of aluminium (SAR+Al) influenced the ecophysiology of three arbuscular mycorrhizal fungi (AMF) in both the germination and symbiotic phases of their life cycle. Acaulospora tuberculata, an isolate from the soil with low pH, exhibited a higher tolerance to environmental stress as compared to Glomus mosseae and G. fistulosum. This higher tolerance may be related to the edaphic conditions of soil of the isolate origin. The histochemical staining of the alkaline phosphatase and NADH-diaphorase activities in the extraradical mycelium (ERM) of the AMF proved to be more sensitive indication of negative effects of the SAR or SAR+Al stress compared to commonly measured parameters of the AMF such as mycorrhizal colonisation or growth of the ERM. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spectroscopic resolution of the picosecond reduction kinetics of the secondary electron acceptor A1 in photosystem I

Forward electron transfer in photosystem I from Synechocystis sp. PCC 6803 has been studied in the picosecond time range with transient absorption spectroscopy in the blue and near-UV spectral regions. From the direct measurement, at 380-390 nm, of the reduction kinetics of the phylloquinone secondary acceptor A1 and from the absence of spectral evolution between 100 ps and 2 ns, we conclude that electron transfer, from the chlorophyll a primary acceptor A0, to A1 occurs directly and completely with a time constant of about 30 ps.     

Sulfate transport in Penicillium chrysogenum: cloning and characterization of the sutA and sutB genes

In industrial fermentations, Penicillium chrysogenum uses sulfate as the source of sulfur for the biosynthesis of penicillin. By a PCR-based approach, two genes, sutA and sutB, whose encoded products belong to the SulP superfamily of sulfate permeases were isolated. Transformation of a sulfate uptake-negative sB3 mutant of Aspergillus nidulans with the sutB gene completely restored sulfate uptake activity. The sutA gene did not complement the A. nidulans sB3 mutation, even when expressed under control of the sutB promoter. Expression of both sutA and sutB in P. chrysogenum is induced by growth under sulfur starvation conditions. However, sutA is expressed to a much lower level than is sutB. Disruption of sutB resulted in a loss of sulfate uptake ability. Overall, the results show that SutB is the major sulfate permease involved in sulfate uptake by P. chrysogenum.     

Improved in vitro embryo development using in vivo matured oocytes from heifers superovulated with a controlled preovulatory LH surge

In bovine in vitro embryo production, the IVM step is rather successful with 80% of the oocytes reaching the MII stage. However, the extent to which the process limits the yield of viable embryos is still largely unknown. Therefore, we compared embryonic developmental capacity during IVC of IVF oocytes which had been matured in vitro with those matured in vivo. In vitro maturation was carried out for 22 h using oocytes (n = 417) obtained from 2- to 8-mm follicles of ovaries collected from a slaughterhouse in M199 with 10% fetal calf serum (FCS), 0.01 IU/mL LH, and 0.01 IU/mL FSH. In vivo matured oocytes (n = 219) were aspirated from preovulatory follicles in eCG/PG/anti-eCG-superovulated heifers 22 h after a fixed time GnRH-induced LH surge; endogenous release of the LH surge was suppressed by a Norgestomet ear implant. This system allowed for the synchronization of the in vitro and in vivo maturation processes and thus for simultaneous IVF of both groups of oocytes. The in vitro developmental potential of in vivo matured oocytes was twice as high (P < 0.01) as that of in vitro matured oocytes, with blastocyst formation and hatching rates 11 d after IVC of 49.3 +/- 6.1 (SEM; n = 10 heifers) vs 26.4 +/- 1.0% (n = 2 replicates), and 39.1 +/- 5.1% vs 20.6 +/- 1.4%, respectively. It is concluded that IVM is a major factor limiting in the in vitro production of viable embryos, although factors such as the lack of normal preovulatory development of IVM oocytes contributed to the observed differences.     

Design of a 5' exonuclease-based real-time PCR assay for simultaneous detection of Bacillus licheniformis, members of the 'B. cereus group' and B. fumarioli in gelatine

AIMS: The design of a fast, sensitive and specific detection method for Bacillus licheniformis, members of the 'B. cereus group' and B. fumarioli in gelatine. METHODS AND RESULTS: Specific Taqman probes were designed and tested in a real-time PCR setting. A specific fluorescent signal could be obtained for all gelatine isolates attributed to these species in one single real-time PCR reaction. After sample preparation, a gelatine sample spiked with 1 CFU provided enough template DNA for a significant signal. CONCLUSION: The potential of a real-time PCR assay for simultaneous detection of B. licheniformis, members of the 'B. cereus group' and B. fumarioli in gelatine is demonstrated. SIGNIFICANCE AND IMPACT OF THE STUDY: Implementation of the assay in gelatine producing plants may shorten delivery terms and inform on hazards to public health and suitable remediation procedures.     

Microtubules become more dynamic but not shorter during preprophase band formation: a possible "search-and-capture" mechanism for microtubule translocation

The dynamic behavior of the microtubule cytoskeleton plays a crucial role in cellular organization, but the physical mechanisms underlying microtubule (re)organization in plant cells are poorly understood. We investigated microtubule dynamics in tobacco BY-2 suspension cells during interphase and during the formation of the preprophase band (PPB), the cytoskeletal structure that defines the site of cytokinesis. Here we show that after 2 h of microtubule accumulation in the PPB and concurrent disappearance elsewhere in the cortex, the PPB is completed and starts to breakdown exponentially already 20 min before the onset of prometaphase. During formation of the PPB, the dynamic instability, i.e., the stochastic alternating between growing and shrinking phases, of the cortical microtubules outside the PPB increases significantly, but the microtubules do not become shorter. Based on this, as well as on the cross-linking of microtubules in the PPB and the lack of evidence for motor involvement, we propose a "search-and-capture" mechanism for PPB formation, in which the regulation of dynamic instability causes the cortical microtubules to become more dynamic and possibly longer, while the microtubule cross-linking activity of the developing PPB preferentially stabilizes these "searching" microtubules. Thus, microtubules gradually disappear from the cortex outside the PPB and aggregate to the forming PPB.     

Post-genomics of lactic acid bacteria and other food-grade bacteria to discover gut functionality

Recent years have seen an explosion in the number of complete or almost complete genomic sequences of lactic acid bacteria and other food-grade bacteria that are used in functional foods to increase the health of the consumer. These have been instrumental in the development of functional, comparative and other post-genomics approaches that provide the possibility to detect, unravel and understand their functionality in the human intestinal tract. In conjunction with other high-throughput approaches, these advances can be exploited in the functional food innovation cycle for developing new or designed probiotic and other bacterial products that impact gut health.     

Fetometry and fetal heart rates between Day 35 and 108 in bovine pregnancies resulting from transfer of either MOET, IVP-co-culture or IVP-SOF embryos

The Large Offspring Syndrome has frequently been reported for in vitro produced calves. The objective of this study was to determine whether any differences in body dimensions (biparietal diameter of the cranium (BPD), cross-section of the abdomen at the insertion of the umbilical cord (CAU)) and heart rate (FHR) can be detected during the first 108 days of gestation between bovine foetuses derived from different methods of embryo production. Three groups of pregnancies with calvings at term resulted from non-surgical transfers of three types of embryos: recipients carrying an embryo obtained by standard MOET procedures (n = 25); recipients carrying an embryo produced in vitro from OPU-derived oocytes, using co-culture-medium (n = 14) or SOF-medium (n = 22). Transrectal ultrasonographic examinations were performed weekly. Ultrasound images were recorded and during off-line analysis FHR, BPD and CAU were determined. For each foetus a curve was fitted and the estimates on fixed time intervals were used as dependent variables in an analysis of variance to detect differences between the three pregnancy groups. Neither gestation length nor birth weight differed significantly between the three pregnancy groups, nor could any differences with respect to BPD, CAU or FHR be detected between Days 35 and 108 of gestation. It is concluded that no differences exist between the early development of bovine foetuses, derived from MOET, IVP-co-culture or IVP-SOF embryos, and resulting in calves with normal birth weights.     

X-linked hydrocephalus: another two families with an L1 mutation

X-linked hydrocephalus is a variable condition caused by mutations in the gene encoding for L1CAM. This gene is located at Xq28. Clinically the spectrum ranges from males with lethal congenital hydrocephalus to mild/moderate mental retardation and spastic paraplegia. Few carrier females show minimal signs of the syndrome. Although most cases are familial, de novo situations have been reported. We report two new families with the syndrome and a L1 mutation. Family 1 has two patients and family 2 a single patient. Clinical diagnosis in all three affected boys was beyond doubt. Prenatal testing through chorionic villus biopsy is possible only with a demonstrated L1 mutation. In lethal sporadic cases neuropathology is very important in order to evaluate for features of the syndrome. We stress the importance of further clinical reports including data on neuropathology and DNA analysis in order to further understand the mechanisms involved in this disorder.