Experimental infection of red dwarf honeybee,Apis florea,with Nosema ceranae

This research is the first record of the infection of Apis florea by Nosema ceranae, a newly identified pathogen of honeybee in Thailand which was initially isolated from A. florea workers. Each Nosema free-bee was fed 2 μl of 50% (w/v) sucrose solution containing 0, 10,000 20,000 or 40,000 Nosema spores/bee. The survival rates of treated bees were significantly lower compared to control bees. Infectivity was not statistically different among the three spore concentrations, whereas no infection was found in control bees. Protein content of control bee hypopharyngeal glands 14 days post inoculation (p.i) was significantly higher (21.47 ± 0.17 mg/bee) compared to all treatments. The infection ratio of bees treated with 40,000 spores/bee increased with time after inoculation. These results suggest that N. ceranae has a significant negative effect on honeybee hypopharyngeal gland protein production and contributes to their shortened life span.     

Sequence and functional analysis of the cloned Neisseria meningitidis CMP-NeuNAc synthetase

The CMP-N-acetylneuraminic acid (CMP-NeuNAc) synthetase gene of Neisseria meningitidis group B is located on a 2.3-kb EcoRI fragment within the cps gene cluster. Nucleotide sequence determination of the gene encoding the CMP-NeuNAc synthetase revealed a 515-bp open reading frame that can encode a 18.9-kDA protein. A computer data base scan revealed a 59.4% identity to the CMP-NeuNAc synthetase gene of E. coli K1. Enzymatic activity was confirmed in vitro and in vivo. Transformation of the CMP-NeuNAc defective E. coli K1 strain EV5 with the meningococcal CMP-NeuNAc synthetase could complement the defect in E. coli.     

The Effect of Traffic Density on Lead Contents in Roadside Soils: An Analysis of Published Data

Data from eight published studies were combined to show that the influence of traffic density on Pb contents in roadside soils increases with proximity to the road.     

Retardation of cell cycle progression in yeast cells recovering from DNA damage: A study at the single cell level

Summary Pedigree analyses of individual yeast cells recovering from DNA damage were performed and time intervals between morphological landmark events during the cell cycle (bud emergence and cell separation), were recorded for three generations. The associated nuclear behavior was monitored with the aid of DAPI staining. The following observations were made: (1) All agents tested (X-rays, MMS, EMS, MNNG, nitrous acid) delayed the first bud emergence after treatment, which indicates inhibition of the initiation of DNA replication. (2) Cells that survived X-irradiation progressed further through the cell cycle in a similar way to control cells. (3) Progress of chemically treated cells became extremely asynchronous because surviving cells stayed undivided for periods of varying length. (4) Prolongation of the time between bud emergence and cell separation was most pronounced for cells treated with the alkylating agents MMS and EMS. This is interpreted as retardation of ongoing DNA synthesis by persisting DNA adducts. (5) Cell cycle prolongation in the second and third generation after treatment was observed only with MMS treated cells. (6) In all experiments, individual cells of uniformly treated populations exhibited highly variable responses.Abbreviations DAPI 4,6-diamidino-2-phenyl-indole - EMS ethyl methanesulfonate - MMS methyl methanesulfonate - MNNG N-methyl-N-nitro-N-nitrosoguanidine     

Characterization of a stable, major DNA polymerase alpha species devoid of DNA primase activity.

We have purified from Xenopus laevis ovaries a major DNA polymerase alpha species that lacked DNA primase activity. This primase-devoid DNA polymerase alpha species exhibited the same sensitivity as the DNA polymerase DNA primase alpha to BuAdATP and BuPdGTP, nucleotide analogs capable of distinguishing between DNA polymerase delta and DNA polymerase DNA primase alpha. The primase-devoid DNA polymerase alpha species also lacked significant nuclease activity indicative of the alpha-like (rather than delta-like) nature of the DNA polymerase. Using a poly(dT) template, the primase-devoid DNA polymerase alpha species elongated an oligo(rA10) primer up to 51-fold more effectively than an oligo(dA10) primer. In direct contrast, the DNA polymerase DNA primase alpha complex showed only a 4.6-fold preference for oligoribonucleotide primers at the same template/primer ratio. The catalytic differences between the two DNA polymerase alpha species were most dramatic at a template/primer ratio of 300. The primase-devoid DNA polymerase alpha species was found at high levels throughout oocyte and embryonic development. This suggests that the primase-devoid DNA polymerase alpha species could play a physiological role during DNA chain elongation in vivo, even if it is chemically related to DNA polymerase DNA primase alpha.     

A major single-stranded DNA binding protein from ovaries of the frog, Xenopus laevis, is lactate dehydrogenase

The most abundant single-stranded DNA binding protein (SSB) found in ovaries of the frog, Xenopus laevis, was purified to electrophoretic homogeneity. Under physiological conditions, the purified SSB lowered the Tm of poly[d(A-T)] and stimulated DNA synthesis by the homologous DNA polymerase DNA primase alpha complex on single-stranded DNA templates. These properties are characteristic of a bona fide single-stranded DNA binding protein. The Stokes radius of native SSB was calculated to be 45 A, corresponding to a molecular mass of about 140 kDa. On SDS polyacrylamide gels, the SSB migrated as a single band with a molecular mass of 36 kDa. We assumed, therefore, that the SSB was a tetramer of 36 kDa subunits. We subsequently discovered that the SSB was LDH, D-lactate dehydrogenase, EC 1.1.1.28. Purified SSB has high LDH specific activity. Following electrophoresis on SDS polyacrylamide gels, the 36 kDa subunits were renatured and exhibited LDH activity. The amino-acid composition of X. laevis SSB/LDH was similar to that of LDH from other species and to other reported single-stranded DNA binding proteins. Mammalian SSB/LDH also preferentially bound single-stranded DNA. Mammalian SSB/LDH bound to RNA as demonstrated by affinity chromatography on poly(A)-agarose and by its effect on translation of mRNA in vitro.     

A “new” genetic polymorphism of a human serum protein: inter-alpha-trypsin-inhibitor

Summary A new genetic polymorphism of a human serum glycoprotein, the inter--trypsin-inhibitor (ITI), has been demonstrated by population and family studies. Sera were examined after neuraminidase treatment by isoelectric focusing on agarose gels followed by immunoblotting or by immunfixation with specific ITI-antiserum. Using this method, three common ITI phenotypes 1, 1–2 and 2, as well as two further rare ITI types 1–3 and 2–3 were disclosed. Genetically, these phenotypes are controlled by three allelic genes that determine a total of six phenotypes. These alleles are designated ITI^*1, ITI^*2 and ITI^*3. The homozygous form of the third allele ITI^*3 has not been found, as yet. The frequencies of ITI were examined in two population samples from Southern Germany (n=248) and from Tyrol, Austria (n=124). The gene frequencies of the common alleles ITI^*1 and ITI^*2 were 0.575 and 0.417, respectively, in Southern Germany, and 0.577 and 0.423, respectively, in Tyrol, Austria. The third allele ITI^*3 was found only in the sample from Southern Germany, thus far, and was calculated to be 0.008.     

Multisegmental cobalt filling of the dorsal giant fibers in the nervous system of the earthworm,Lumbricus terrestris

Summary The anatomical organization of the two dorsal giant fiber systems of the earthworm Lumbricus terrestris is demonstrated in whole mounts and serial-section reconstructions based on backfillings of the ventral nerve cord with cobalt chloride. Both the medial and lateral fiber systems can be labeled selectively over more than ten body segments. They show a characteristic segmental pattern of collaterals with some modification in tail segments and of dorsal plasma protrusions in the unpaired medial giant fiber presumably representing openings in the myelin sheath. We found no multisegmental cobalt transport in other large neurons of the nerve cord. Cobalt passes through the segmentai septa between consecutive axonal elements of the metameric giant fibers and presumably also through commissural contacts between specific collaterals of the lateral giant fibers. Since these sites of contact are known to represent electrical synapses, cobalt coupling may, in L. terrestris, correlate with functional electrotonic coupling.Abbreviations CL collateral of lateral giant fiber - CM collateral of medial giant fiber - GIN giant interneuron - LGF lateral giant fiber - MGF medial giant fiber - SN segmental nerve     

The stimulating effect of a cold, dark pretreatment on the etioplast/chloroplast transformation of angiosperms. I. The stimulating effect of cold predarkening on different stages of greening under white light

Schönbohm, E., Stute, U., Thienhaus, P. and Werner, U. 1988. The stimulating effect of a cold, dark pretreatment on the etioplast/chloroplast transformation of angiosperms I. The stimulating effect of cold predarkening on different stages of greening under white light. - Physiol. Plant. 72: 541–546.
The etioplast/chloroplast transformation in angiosperms is controlled by light; most of the processes are mediated by phytochrome. We have shown that in the primary leaves of etiolated seedlings of wheat ( Triticum aestivum L. cv. Kolibri), fire-bean ( Phaseolus multiflorus L. cv. Preisgewinner) and in the cotyledons of etiolated sun flower seedlings ( Helianthus annuus L. cv. macrocarpa) the chlorophyll accumulation in the phase after the end of the lag phase can be greatly stimulated by a cold predarkening period. This effect is not necessarily coupled with a red preirradiation. Furthermore the lag phase can be dramatically shortened by the cold, dark pretreatment, whereas the amount of photoconvertible protochlorophyll(ide) in the darkness remains unaffected by the cold, dark pretreatment. The stimulating effect of a cold, predarkening period on greening is fully reversible by a warm, dark phase that is placed between the cold period and the onset of the continuous white light phase. These findings cannot be generalized: We could demonstrate that in the tropical plant Momordica charantia greening under white light was not affected by different temperature pretreatments during predarkening. The stimulating effect of a cold, predarkening period on greening is assumed to have ecological relevance.