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11.
12.
Variation in heat-shock proteins among species of desert fishes (Poeciliidae, Poeciliopsis) 总被引:4,自引:0,他引:4
Analysis of the heat-shock proteins (hsps) of six closely related species
of Poeciliopsis demonstrated the existence of biochemical diversity in the
hsp100, hsp70, hsp60, and hsp30 protein families among species. Each
species expressed five to seven hsp70-related isoforms. Constitutive 70-kD
isoforms were identical among species, but four different patterns of
heat-inducible isoforms were seen in these six species. Members of the
hsp70 family of molecular chaperones are included among the most highly
conserved proteins known, and the possibility of variation in hsp70 among
closely related species has rarely been addressed. The hsp30 family is
known to be less conserved than the hsp70 family, and, as expected, the
Poeciliopsis hsp30 patterns showed more variation. Most of the hsp30
isoforms characteristic of a particular species were unique to that
species. Hsp100 and hsp60 were identical in five of the species, but
alternate isoforms were found in P. monacha. The small size and limited
geographical distribution of the P. monacha population have probably
contributed to the uniqueness of the monacha pattern. Two of the species
were shown to acquire thermotolerance, the ability to withstand normally
lethal temperatures when subjected to a gradual temperature increase.
Rapid-heating protocols commonly used to establish critical thermal maxima
of organisms do not include this inducible component of thermoresistance
and therefore do not adequately assess an organism's capacity to withstand
thermal stress.
相似文献
13.
Study of the dynamics of neutralization escape mutants in a chimpanzee naturally infected with the simian immunodeficiency virus SIVcpz-ant. 总被引:2,自引:1,他引:1 下载免费PDF全文
P N Nyambi P Lewi M Peeters W Janssens L Heyndrickx K Fransen K Andries M Vanden Haesevelde J Heeney P Piot G van der Groen 《Journal of virology》1997,71(3):2320-2330
Here we report on the use of spectral map analysis of time-paired sequential neutralization data of 11 serum samples of a chimpanzee naturally infected with a simian immunodeficiency virus (SIVcpz-ant) and 8 primary consecutive SIVcpz-ant isolates, taken at about 4-month intervals. The analysis reveals the existence of three SIVcpz-ant isolate and serum neutralization clusters. Each cluster groups virus isolates and/or sera based on similarities of their neutralization spectra. On average, neutralization escape mutants emerged after 15 months and mounted a neutralization response approximately 8 months later. The entire gp160 regions of eight consecutive isolates were sequenced and analyzed by a new statistical method called polygram, which allowed the deduction of amino acid sequence motifs of gp160 which were specific for SIVcpz-ant isolates belonging to the same isolate neutralization clusters. Changes in specific amino acid quadruplets in V1, V2, C3, V4, V5, and CD4 domains of gp120 and gp40 were seen to correlate with the neutralization clusters with most of the specific changes occurring in the V4 region. This method of analysis may facilitate an understanding of the study of the dynamic interplay between human immunodeficiency virus (HIV) and host neutralization responses as well as providing possible insights into mechanisms of persistence of HIV-1-related lentiviruses in their natural hosts. 相似文献
14.
Variation in heat shock proteins within tropical and desert species of poeciliid fishes 总被引:8,自引:0,他引:8
Norris CE; diIorio PJ; Schultz RJ; Hightower LE 《Molecular biology and evolution》1995,12(6):1048-1062
The 70-kilodalton heat shock protein (hsp70) family of molecular
chaperones, which contains both stress-inducible and normally abundant
constitutive members, is highly conserved across distantly related taxa.
Analysis of this protein family in individuals from an outbred population
of tropical topminnows, Poeciliopsis gracilis, showed that while
constitutive hsp70 family members showed no variation in protein isoforms,
inducibly synthesized hsp70 was polymorphic. Several species of
Poeciliopsis adapted to desert environments exhibited lower levels of
inducible hsp70 polymorphism than the tropical species, but constitutive
forms were identical to those in P. gracilis, as they were in the
confamilial species Gambusia affinis. These differences suggest that
inducible and constitutive members of this family are under different
evolutionary constraints and may indicate differences in their function
within the cell. Also, northern desert species of Poeciliopsis synthesize a
subset of the inducible hsp70 isoforms seen in tropical species. This
distribution supports the theory that ancestral tropical fish migrated
northward and colonized desert streams; the subsequent decrease in
variation of inducible hsp70 may have been due to genetic drift or a
consequence of adaptation to the desert environment. Higher levels of
variability were found when the 30- kilodalton heat shock protein (hsp30)
family was analyzed within different strains of two desert species of
Poeciliopsis and also in wild-caught individuals of Gambusia affinis. In
both cases the distribution of hsp30 isoform diversity was similar to that
seen previously with allozyme polymorphisms.
相似文献
15.
16.
M. Couturier J. Janssens F. Bex A. Desmyter I. Bonnevalle 《Molecular & general genetics : MGG》1979,169(1):113-116
Summary In this paper, we report the construction in vitro of chimerae between lambdoid replacement vectors (Murray et al., 1977) and the miniF Apr plasmid: pSC138 (Timmis et al., 1975). F recombinants were shown to be chimerae between the and the F replicons. By genetical tests, we have demonstrated that both and F replication mechanisms are functional: the F recombinant behaves as a non defective plaque forming phage on sensitive bacteria and establishes itself as a stable plasmid on recA F- homoimmune bacteria. In the extra-chromosomal state, the F recombinant apparently retains the controlled autonomous replication and the FI incompatibility characteristics of the F plasmid. The potential experimental uses of these phages are discussed. 相似文献
17.
C A Hales S W Musto S Janssens W Jung D A Quinn M Witten 《Journal of applied physiology》1992,72(2):555-561
The pulmonary edema of smoke inhalation is caused by the toxins of smoke and not the heat. We investigated the potential of smoke consisting of carbon in combination with either acrolein or formaldehyde (both common components of smoke) to cause pulmonary edema in anesthetized sheep. Seven animals received acrolein smoke, seven animals received a low-dose formaldehyde smoke, and five animals received a high-dose formaldehyde smoke. Pulmonary arterial pressure, pulmonary capillary wedge pressure, and cardiac output were not affected by smoke in any group. Peak airway pressure increased after acrolein (14 +/- 1 to 21 +/- 2 mmHg; P less than 0.05) and after low- and high-dose formaldehyde (14 +/- 1 to 21 +/- 1 and 20 +/- 1 mmHg, respectively; both P less than 0.05). The partial pressure of O2 in arterial blood fell sharply after acrolein [219 +/- 29 to 86 +/- 9 (SE) Torr; P less than 0.05] but not after formaldehyde. Only acrolein resulted in a rise in lung lymph flow (6.5 +/- 2.2 to 17.9 +/- 2.6 ml/h; P less than 0.05). Lung lymph-to-plasma protein ratio was unchanged for all three groups, but clearance of lymph protein was increased after acrolein. After acrolein, the blood-free extravascular lung water-to-lung dry weight ratio was elevated (P less than 0.05) compared with both low- and high-dose formaldehyde groups (4.8 +/- 0.4 to 3.3 +/- 0.2 and 3.6 +/- 0.2, respectively). Lymph clearance (ng/h) of thromboxane B2, leukotriene B4, and the sulfidopeptide leukotrienes was elevated after acrolein but not formaldehyde.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
18.
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20.
Lihua Zhang Fenghui Yuan Junhong Bai Hongtao Duan Xueying Gu Longyu Hou Yao Huang Mingan Yang Jin‐Sheng He Zhenhua Zhang Lijun Yu Changchun Song David A. Lipson Donatella Zona Walter Oechel Ivan A. Janssens Xiaofeng Xu 《Ecology letters》2020,23(5):821-830
Grassland ecosystems account for more than 10% of the global CH4 sink in soils. A 4‐year field experiment found that addition of P alone did not affect CH4 uptake and experimental addition of N alone significantly suppressed CH4 uptake, whereas concurrent N and P additions suppressed CH4 uptake to a lesser degree. A meta‐analysis including 382 data points in global grasslands corroborated these findings. Global extrapolation with an empirical modelling approach estimated that contemporary N addition suppresses CH4 sink in global grassland by 11.4% and concurrent N and P deposition alleviates this suppression to 5.8%. The P alleviation of N‐suppressed CH4 sink is primarily attributed to substrate competition, defined as the competition between ammonium and CH4 for the methane mono‐oxygenase enzyme. The N and P impacts on CH4 uptake indicate that projected increases in N and P depositions might substantially affect CH4 uptake and alter the global CH4 cycle. 相似文献