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1.
Microbial growth on carbon monoxide 总被引:14,自引:0,他引:14
The utilization of carbon monoxide as energy and/or carbon source by different physiological groups of bacteria is described and compared. Utilitarian CO oxidation which is coupled to the generation of energy for growth is achieved by aerobic and anaerobic eu- and archaebacteria. They belong to the physiological groups of aerobic carboxidotrophic, facultatively anaerobic phototrophic, and anaerobic acetogenic, methanogenic or sulfate-reducing bacteria. The key enzyme in CO oxidation is CO dehydrogenase which is a molybdo iron-sulfur flavoprotein in aerobic CO-oxidizing bacteria and a nickel-containing iron-sulfur protein in anaerobic ones. In carboxidotrophic and phototrophic bacteria, the CO-born CO2 is fixed by ribulose bisphosphate carboxylase in the reductive pentose phosphate cycle. In acetogenic, methanogenic, and probably in sulfate-reducing bacteria, CODH/acetyl-CoA synthase directly incorporates CO into acetyl-CoA.In plasmid-harbouring carboxidotrophic bacteria, CO dehydrogenase as well as enzymes involved in CO2 fixation or hydrogen utilization are plasmid-encoded. Structural genes encoding CO dehydrogenase were cloned from carboxidotrophic, acetogenic and methanogenic bacteria. Although they are clustered in each case, they are genetically distinct.Soil is a most important biological sink for CO in nature. While the physiological microbial groups capable of CO oxidation are well known, the type and nature of the microorganisms actually representing this sink are still enigmatic. We also tried to summarize the little information available on the nutritional and physicochemical requirements determining the sink strength. Because CO is highly toxic to respiring organisms even in low concentrations, the function of microbial activities in the global CO cycle is critical. 相似文献
2.
Sujata Misra Kshudiram Naskar Dwijen Sarkar Dilip Kumar Ghosh 《Molecular and cellular biochemistry》1991,102(1):13-18
Summary
Leishmania donovani, the etiological agent for the disease visceral leishmaniasis, attach themselves to the macrophages for initiation of the disease. The attachment process has been found to be regulated by Ca2+ ions. Verapamil, a Ca2+-channel blocker inhibits Leishmania-macrophage attachment. The inhibitory effect is increased with time. Nifedipine, another Ca2+-channel blocker exhibits the same effect. The attachment process is stimulated by Ca2+-ionophore alone. The inhibitory effects of the calcium channel blockers are reversed by the ionophore. 相似文献
3.
Dilip M. Shah Cathy M. Hironaka Roger C. Wiegand Elizabeth I. Harding Gwen G. Krivi David C. Tiemeier 《Plant molecular biology》1986,6(4):203-211
Summary We have used the cDNA clone encoding maize glutathione-S-transferase (GST I) to isolate a genomic DNA clone containing the complete GST I gene. Nucleotide sequence analysis of the cDNA and genomic clones has yielded a complete amino acid sequence for maize GST I and provided the exon-intron map of its gene. The mRNA homologous sequences in the maize GST I gene consist of a 107 bp 5 untranslated region, a 642 bp coding region and 340 bp of the 3 untranslated region. They are divided into three exons by two introns which interrupt the coding region. The 5 untranslated spacer contains an unusual sequence of pentamer AGAGG repeated seven times. The inbred maize line (Missouri 17) contains a single gene for GST I, whereas the hybrid line (3780A) contains two genes. Nucleotide sequence analysis of the primer extended cDNA products reveals that the 5 untranslated regions of the two genes in the hybrid 3780A are identical except for a 6 bp internal deletion (or insertion). The amino acid sequence of maize GST I shares no apparent sequence homology with the published sequences of animal GST's and represents the first published sequence of a plant GST. re]19850813 ac]19851126 相似文献
4.
In SDS-PAGE the immune complexes (IC) of kala-azar patient sera showed intense bands at 55 kDa and 20 kDa corresponding to heavy and light chains of immunoglobulins. In immunoblot experiment, kala-azar and normal IC after treatment with patient sera showed multiple bands of which the band at 55 kDa was most prominent in kala-azar IC. It is known that in kala-azar sera antihuman IgG is present, so the heavy band at 55 kDa region may be due to higher amount of IgG and/or other antigen(s) present at that region. Immunoblot experiments of kala-azar IC with anti gp63 also developed a major band at 55 kDa. It suggests that the antigen (55 kDa) and gp63 have common antigenic epitope (s). Normal IC did not react with anti gp63 indicating absence of this antigen in normal IC. Antigenic similarity between the IC antigen (55 kDa) and gp63 indicated that the former antigen may have been processed from gp63. In summary, identification of a parasite antigen (55 kDa) in IC of kala-azar patients sera may be useful in developing a serodiagnostic assay for visceral leishmaniasis. (Mol Cell Biochem130: 11–17, 1994)Abbreviations IC
Immune Complexes
- PEG
Polyethylene Glycol (Mol wt 8000)
- PBS
Phosphate Buffer Saline
- VL
Visceral Leishmaniasis
- AVL
American Visceral Leishmaniasis
- IgG
Immunoglobulin G
- TBS
Tris Buffer Saline
- SDS-PAGE
Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis
- gp63
A leishmanial surface glycoprotein of molecular mass 63,000
- TEMED
N,N,N,N-Tetramethylethylenediamine 相似文献
5.
Jeffrey R. Laduca Dilip K. Sinha 《In vitro cellular & developmental biology. Animal》1993,29(10):789-794
Summary Carcinogenesis is a lengthy process which eventually culminates in the transformed phenotype, cancer. However, much remains
to be defined about the process of transformation. In vivo models for the study of the carcinogenic process present limitations
because it is not possible to detect the premalignant stages in the animals. An in vitro model, on the other hand, facilitates
the study of the carcinogenic process because it enables one to dissect out the crucial events required for carcinogenesis
to occur. As carcinogenesis is believed to be a multistep process; initiation, promotion, and progression, a multistep, in
vitro system has been devised in our laboratory to mimic each of these stages. We have previously shown the formation of “microtumors”
in collagen gels, induced by 7,12-dimethylbenz(a)anthracene. In the present study the direct acting water soluble, mammary
carcinogen,N-nitroso-N-methylurea (NMU) was used for tumorigenesis of mammary epithelial cells in culture. Mammary epithelial cells from virgin
Sprague-Dawley rats were propagated and exposed to single or multiple doses of NMU while growing as a monolayer in glass petri
dishes (initiation). Initiated cells were then plated into a collagen gel matrix culture. Prolonged growth in the collagen
gels afforded for the progression of the transformed cells into discernable microtumors in the three-dimensional matrix of
the collagen. The morphology of these “tumors” was determined by histologic sections of the gels. Fewer, if any, such structures
existed in the untreated gels. 相似文献
6.
Stem explants obtained from a mature tree of Ziziphus mauritiana Lamk were grown on modified Murashige and Skoog medium containing 3800 mg l-1 potassium nitrate, 2475 mg l-1 ammonium nitrate, 11 M benzyladenine and 0.5 M indole-3-acetic acid. During successive subcultures 15–20 shoots per inoculum were produced. Rooting was induced by pretreatment with 50 M indolebutyric acid or 1-naphthaleneacetic acid for 24 h followed by transfer to auxin-free White's medium. Plantlets grew well in a soil and vermiculite mixture.Abbreviations IAA
Indole-3-acetic acid
- NAA
1-naphthaleneacetic acid
- BA
benzyladenine
- MS
Murashige and Skoog 相似文献
7.
Dilip Ghosh Sumit Bhose R. Manimekalai S. Gowda 《Journal of plant biochemistry and biotechnology.》2013,22(3):343-347
Phytoplasma infected acid lime plants in India develop characteristic symptoms like small chlorotic leaves, multiple sprouting and shortened internodes. Leaves drop prematurely and infected branches have distorted twigs resembling witches’ broom appearance which eventually show die-back symptoms. During its first report in 1999, witches’ broom disease identification was made on the basis of symptomatology and electron microscopy. However, molecular techniques have proved to be more accurate and reliable for phytoplasma detection than the conventional methods. During survey in the year 2010 six samples were collected from infected acid lime plants showing typical field symptoms from Vidarbha region of Maharastra. Initially, phytoplasma bodies were observed in phloem tissues of all six symptomatic samples under JEM 100S transmission electron microscope and all these six samples were subsequently screened using different set of phytoplasma specific universal primers by nested PCR, a widely recommended molecular technique for phytoplasma detection. In the present study P1/P7 “universal” phytoplasma-primer set was used for first round of PCR and amplified products were processed separately for nested PCR with three different nested primer pairs viz. R16F2n/R16R2, R16mF2/R16mR1 and fU5/rU3. The presence of phytoplasma was confirmed in all six suspected samples and one representative ~1.2 kb size amplicon was sequenced and deposited in GenBank as Candidatus Phytoplasma species AL-M (JQ808143). This is the first report of PCR based molecular detection of phytoplasma-induced witches’ broom disease of acid lime (WBDL) in India. Further molecular evaluation to determine the identity to the species level is in progress. 相似文献
8.
Effect of storage, photoperiod and mechanical scarification on seed germination in Ocimum americanum
Dilip Amritphale Y. K. Mukhiya J. C. Gupta Shamanta Iyengar 《Physiologia plantarum》1984,61(4):649-652
Seeds of Ocimum americanum L. display an absolute light requirement for germination. The minimal length of the daily photoperiod required to induce a high germination decreased with increasing seed age, but the length of the photoperiod under potential control of terminal far-red light inhibition remained unchanged. There was a gradual escape from the far-red inhibition with increase in the length of the photoperiod. Seeds developed flash photosensitivity after the first 13 h photoperiod. Scarification treatment did not allow the seeds to bypass the light requirement, but it enhanced the germination considerably. Under conditions of natural day length in the field, weakening of the testa by sand may abolish the need for a second exposure to light for most of the seed population, thus rendering them non-photoperiodic. 相似文献
9.
10.