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81.
Barbara Hickel 《Hydrobiologia》1988,161(1):41-48
The life cycle of Ceratium furcoides (Levander) Langhans which features sexual reproduction is described for the first time in situ from the lake Plußsee (northern West Germany). Anisogamic copulation occurs during the bloom period in July–August by incorporation of the male gamete by the female gamete, resulting in an overwintering planozygote. The planozygote develops into a benthic hypnozygote which germinates in spring to establish a planomeiocyte. The morphology and structure of the stages of the life cycle are described using light and scanning electron microscopy. 相似文献
82.
Integration and mapping of Bacillus megaterium genes which code for small, acid-soluble spore proteins and their protease. 总被引:4,自引:4,他引:0
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Four genes (ssp genes) coding for small, acid-soluble spore proteins of Bacillus megaterium and the gene for the protease that cleaves them during germination were cloned in the integratable plasmid pJH101. Each plasmid was integrated into the B. megaterium chromosome by a Campbell-type mechanism, allowing mapping of all five genes. The gene for the small, acid-soluble spore protein-specific protease (gpr) mapped near rib, and the sspA gene mapped between argA and hisA. The three other genes of the spp gene family (sspB, -D, and -F) all mapped near metC/D, with the order: sspF-sspD-metC/D-hemA-argO-sspB. While neither gpr nor sspF has been mapped in B. subtilis, the positions of the sspA, -B, and -D loci are similar in B. megaterium and B. subtilis, suggesting that the members of this multigene family have not recently undergone significant movement on the chromosome. It appears that more gene rearrangement has occurred in the flanking genes than has occurred in the ssp family of genes producing the small, acid-soluble spore proteins. 相似文献
83.
Absence of Transient Elevated UV Resistance during Germination of Bacillus subtilis Spores Lacking Small, Acid-Soluble Spore Proteins α and β
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Germinating spores of Bacillus subtilis mutants which lack small, acid-soluble spore proteins α and β did not exhibit the transient elevated UV resistance seen during germination of wild-type spores. 相似文献
84.
Seasonal variations in levels of serum testosterone, dihydrotestosterone (DHT), reproductive behavior, and social behavior were investigated in 12 adult males (5 to 20 + years of age) of the Oregon troop of Japanese macaques (Macaca fuscata). Blood samples were collected at 2- to 4-month intervals, and behaviors were monitored twice weekly over a 15-month period. Significant seasonal variations in levels of testosterone and DHT, and in frequencies of mount series, ejaculations, number of female partners, displays, courtship, and aggression were observed. Seasonal variations in reproductive and social behaviors did not correlate with seasonal variations in androgen levels because seasonal increases in these behaviors followed seasonal increases in the androgens with a 1- to 2-month delay. However, significant correlations between increased androgen levels and the onset of mating activity occur when mean monthly frequencies of mount series are shifted 1 to 2 months earlier to coincide with the rise in serum androgen levels. The frequency of adult male play and male-male mounting increased significantly when androgen levels were low. We suggest that photoperiod changes may function as a proximate cue in male Japanese macaques which induces a state of biological readiness for mating, and the behavioral consequences (i.e., mating) are then dependent upon the presence of receptive females. 相似文献
85.
The binding of germanium to Pseudomonas putida ATCC 33015 was investigated by using whole intact cells grown in a medium supplemented with GeO2 and catechol or acetate. Electron-microscopic examination of the control and metal-loaded samples revealed that germanium was bound within the cell envelope. A certain number of small electron-dense deposits of the bound element were found in the cytoplasm when the cells were grown in the presence of GeO2 and catechol. The study of germanium distribution in cellular fractions revealed that catechol facilitated the intracellular accumulation of this element. 相似文献
86.
Barbara Kluve-Beckerman George L. Long Merrill D. Benson 《Biochemical genetics》1986,24(11-12):795-803
Serum amyloid A (SAA) is an acute-phase reactant and precursor to amyloid A protein, the major constituent of the fibril deposits of reactive amyloidosis. The factors determining whether the 104-amino acid SAA molecule is converted into the 76-amino acid amyloid A protein and deposited as fibrils are not known. As an initial step toward investigating the possibility that a particular primary structure of SAA is involved in amyloid formation, we have cloned and determined the nucleotide sequence of human SAA-specific cDNAs. The first clone, selected using an oligonucleotide probe, was shown to encode the signal peptide and amino-terminal region of SAA. The cDNA of this clone served as probe in the selection of two distinct, full-length SAA cDNAs, initially differentiated by the presence (pSAA21) or absence (pSAA82) of a PstI site in the coding sequence. The complete nucleotide sequence of pSAA82 cDNA was determined. Since there appear to be multiple human SAA alleles, it is conceivable that their differential expression is important to amyloid formation. 相似文献
87.
James V. Moroney N. E. Tolbert Barbara B. Sears 《Molecular & general genetics : MGG》1986,204(2):199-203
Summary Six independently isolated mutants of Chlamydomonas reinhardtii that require elevated CO2 for photoautotrophic growth were tested by complementation analysis. These mutants are likely to be defective in some aspect of the algal concentrating mechanism for inorganic carbon as they exhibit CO2 fixation and inorganic carbon accumulation properties different from the wild-type. Four of the six mutants defined a single complementation group and appear to be defective in an intracellular carbonic anhydrase. The other two mutations represent two additional complementation groups.Abbreviations HS
high salt medium which has 13 mM phosphate at pH 6.8
- HSA
high salt plus 36 mM acetate medium
- YA
high salt medium with 4 g yeast extract per L and 36mM acetate
- Arg
arginine
- cia-
CO2 accumulation mutants that cannot grow on low CO2
- Ci
inorganic carbon (CO2+HCO
-
3
)
- CA
carbonic anhydrase
- mt
mating type
Supported in part by the McKnight Foundation and by NSF grant PCM 8005917 and published as journal article 11924 from the Michigan State Agriculatural Experiment Station 相似文献
88.
Enhancement of Oxygen-Evolution in Photosystem II-Phycobilisome Particles from Porphyridium cruentum
Oxygen-evolving photosystem II-phycobilisome particles froma red alga were inhibited 5080% by aging, dilution, lowpH and salt-washing. Bovine serum albumin, and dithiothreitolwere found to stimulate activity in all but salt-washed particles.CaCl2 and MnCl2 partially restored activity lost after agingor dilution.
1Current address: Waksman Institute of Microbiology, RutgersUniversity, Piscataway, New Jersey 08854-0759, U.S.A. (Received October 5, 1985; Accepted March 31, 1986) 相似文献
89.
Cloning and nucleotide sequence of the Bacillus megaterium gene coding for small, acid-soluble spore protein B. 总被引:5,自引:5,他引:0
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The Bacillus megaterium gene coding for small, acid-soluble spore protein (SASP) B was cloned and its nucleotide sequence was determined. The amino acid sequence predicted from the DNA sequence was identical to that determined previously for SASP B, with the exception of the amino-terminal methionine predicted from the gene sequence which is presumably removed posttranslationally and an asparagine residue predicted at position 21 which was originally identified as an aspartate residue. The mRNA encoded by the SASP B gene is synthesized for only a discrete period midway in sporulation, in parallel with mRNAs coding for other SASPs. The small size of the SASP B mRNA (365 nucleotides) indicated that the mRNA is monocistronic. The SASP B gene itself hybridized strongly to only one band in Southern blots of restriction enzyme digests of B. megaterium DNA, suggesting that the SASP B gene is not a member of a highly conserved multigene family, as is the case for other SASP genes. 相似文献
90.
Three related centromere proteins are absent from the inactive centromere of a stable isodicentric chromosome 总被引:13,自引:0,他引:13
We developed an aqueous spreading procedure that permits simultaneous analysis of human chromosomes by Q-banding and indirect immunofluorescence. Using this methodology and anticentromere antibodies from an autoimmune patient we compared the active and inactive centromeres of an isodicentric X chromosome. We show that a family of structurally related human centromere proteins (CENP-A, CENP-B, and CENP-C) is detectable only at the active centromere. These antigens therefore may be regarded both as morphological and functional markers for active centromeres. 相似文献