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91.
Roger Huerlimann Eike J. Steinig Heather Loxton Kyall R. Zenger Dean R. Jerry Kirsten Heimann 《Gene》2014
Lipids from microalgae have become a valuable product with applications ranging from biofuels to human nutrition. While changes in fatty acid (FA) content and composition under nitrogen limitation are well documented, the involved molecular mechanisms are poorly understood. Acetyl-CoA carboxylase (ACCase) is a key enzyme in the FA synthesis and elongation pathway. Plastidial and cytosolic ACCases provide malonyl-CoA for de novo FA synthesis in the plastid and FA elongation in the endoplasmic reticulum, respectively. The present study aimed at investigating the expression of plastidial and cytosolic ACCase in Chromera velia and Isochrysis aff. galbana (TISO) and their impact on FA content and elongation level when grown under nitrogen-deplete conditions. In C. velia, plastidial ACCase was significantly upregulated during nitrogen starvation and with culture age, strongly correlating with increased FA content. Conversely, plastidial ACCase of I. aff. galbana was not differentially expressed in nitrogen-deplete cultures, but upregulated during the logarithmic phase of nitrogen-replete cultures. In contrast to plastidial ACCase, the cytosolic ACCase of C. velia was downregulated with culture age and nitrogen-starvation, strongly correlating with an increase in medium-chain FAs. In conclusion, the expression of plastidial and cytosolic ACCase changed with growth phase and nutrient status in a species-specific manner and nitrogen limitation did not always result in FA accumulation. 相似文献
92.
93.
Regulation of cellular adhesion molecule expression in murine oocytes, peri-implant ation and post-implantation embryos 总被引:2,自引:0,他引:2
DAVID P LU LINA TIAN CHRIS O'''' NEILL NICHOLAS JC KING Department of Pathology University of Sydney NSW AustraliaHuman Reproduction Unit Department of Physiology University of Sydney Royal North Shore Hospital NSW Australia 《Cell research》2002,(Z2)
Expression of the adhesion molecules, ICAM-1, VCAM-1, NCAM, CD44, CD49d (VLA-4, a chain), and CDlla (LFA-1, a chain) on mouse oocytes, and pre- and peri-implantation stage embryos was examined by quantitative indirect immunofluorescence microscopy. ICAM-1 was most strongly expressed at the oocyte stage, gradually declining almost to undetectable levels by the expanded blastocyst stage. NCAM, also expressed maximally on the oocyte, declined to undetectable levels beyond the morula stage. On the other hand, CD44 declined from highest expression at the oocyte stage to show a second maximum at the compacted 8-cell/morula. This molecule exhibited high expression around contact areas between trophecto-derm and zona pellucida during blastocyst hatching. CD49d was highly expressed in the oocyte, remained significantly expressed throughout and after blastocyst hatching was expressed on the polar trophecto-derm. Like CD44, CD49d declined to undetectable levels at the blastocyst outgrowth stage. Expression of both 相似文献
94.
95.
Paul REL Lafond T Müller-Graf CDM Nithiuthai S Brey PT Koella JC 《BMC evolutionary biology》2004,4(1):1-13
Background
Theoretical studies suggest that direct and indirect selection have the potential to cause substantial evolutionary change in female mate choice. Similarly, sexual selection is considered a strong force in the evolution of male attractiveness and the exaggeration of secondary sexual traits. Few studies have, however, directly tested how female mate choice and male attractiveness respond to selection. Here we report the results of a selection experiment in which we selected directly on female mating preference for attractive males and, independently, on male attractiveness in the guppy, Poecilia reticulata. We measured the direct and correlated responses of female mate choice and male attractiveness to selection and the correlated responses of male ornamental traits, female fecundity and adult male and female survival.Results
Surprisingly, neither female mate choice nor male attractiveness responded significantly to direct or to indirect selection. Fecundity did differ significantly among lines in a way that suggests a possible sexually-antagonistic cost to male attractiveness.Conclusions
The opportunity for evolutionary change in female mate choice and male attractiveness may be much smaller than predicted by current theory, and may thus have important consequences for how we understand the evolution of female mate choice and male attractiveness. We discuss a number of factors that may have constrained the response of female choice and male attractiveness to selection, including low heritabilities, low levels of genetic (co)variation in the multivariate direction of selection, sexually-antagonistic constraint on sexual selection and the "environmental covariance hypothesis".96.
97.
Y Deng J Zhao D Sakurai KM Kaufman JC Edberg RP Kimberly DL Kamen GS Gilkeson CO Jacob RH Scofield CD Langefeld JA Kelly ME Alarcón-Riquelme BIOLUPUS GENLES Networks JB Harley TJ Vyse BI Freedman PM Gaffney KM Sivils JA James TB Niewold RM Cantor W Chen BH Hahn EE Brown PROFILE BP Tsao 《Arthritis research & therapy》2012,14(Z3):A5
98.
Christiane Riedel Benjamin Lamp Manuela Heimann Matthias K?nig Sandra Blome Volker Moennig Christian Schüttler Heinz-Jürgen Thiel Tillmann Rümenapf 《PLoS pathogens》2012,8(3)
Core protein of Flaviviridae is regarded as essential factor for nucleocapsid formation. Yet, core protein is not encoded by all isolates (GBV- A and GBV- C). Pestiviruses are a genus within the family Flaviviridae that affect cloven-hoofed animals, causing economically important diseases like classical swine fever (CSF) and bovine viral diarrhea (BVD). Recent findings describe the ability of NS3 of classical swine fever virus (CSFV) to compensate for disabling size increase of core protein (Riedel et al., 2010). NS3 is a nonstructural protein possessing protease, helicase and NTPase activity and a key player in virus replication. A role of NS3 in particle morphogenesis has also been described for other members of the Flaviviridae (Patkar et al., 2008; Ma et al., 2008). These findings raise questions about the necessity and function of core protein and the role of NS3 in particle assembly. A reverse genetic system for CSFV was employed to generate poorly growing CSFVs by modification of the core gene. After passaging, rescued viruses had acquired single amino acid substitutions (SAAS) within NS3 helicase subdomain 3. Upon introduction of these SAAS in a nonviable CSFV with deletion of almost the entire core gene (Vp447Δc), virus could be rescued. Further characterization of this virus with regard to its physical properties, morphology and behavior in cell culture did not reveal major differences between wildtype (Vp447) and Vp447Δc. Upon infection of the natural host, Vp447Δc was attenuated. Hence we conclude that core protein is not essential for particle assembly of a core-encoding member of the Flaviviridae, but important for its virulence. This raises questions about capsid structure and necessity, the role of NS3 in particle assembly and the function of core protein in general. 相似文献
99.
In spite of the increasing application of DNA fingerprinting to natural
populations and to the genetic identification of humans, explicit methods
for estimation of basic population genetic parameters from DNA
fingerprinting data have not been developed. Contributing to this omission
is the inability to determine, for multilocus fingerprinting probes,
relatively important genetic information, such as the number of loci, the
number of alleles, and the distribution of these alleles into specific
loci. One of the most useful genetic parameters that could be derived from
such data would be the average heterozygosity, which has traditionally been
employed to measure the level of genetic variation within populations and
to compare genetic variation among different loci. We derive here explicit
formulas for both the estimation of average heterozygosity at multiple
hypervariable loci and a maximum value for this estimate. These estimates
are based upon the DNA restriction-pattern matrices that are typical for
fingerprinting studies of humans and natural populations. For several
empirical data sets from our laboratory, estimates of average and maximal
heterozygosity are shown to be relatively close to each other. Furthermore,
variances of these statistics based on simulation studies are relatively
small. These observations, as well as consideration of the effect of
missing alleles and alternate numbers of loci, suggest that the average
heterozygosity can be accurately estimated using phenotypic DNA fingerprint
patterns, because this parameter is relatively insensitive to the lack of
certain genetic information.
相似文献
100.
Differential sympathetic and angiotensinergic responses in rats submitted to low- or high-salt diet 总被引:2,自引:0,他引:2
Carillo BA Beutel A Mirandola DA Vidonho AF Furukawa LN Casarini D Campos RR Dolnikoff MS Heimann JC Bergamaschi CT 《Regulatory peptides》2007,140(1-2):5-11
The present study was designed to evaluate, in Wistar rats, the effect of high- or low-salt diet on the hemodynamic parameters and on the renal and lumbar sympathetic nerve activity. The renal gene expression of the renin angiotensin system components was also evaluated, aiming to find some correlation between salt intake, sodium homeostasis and blood pressure increase. Male Wistar rats received low (0.06% Na, TD 92141-Harlan Teklad), a normal (0.5% Na, TD 92140), or a high-salt diet (3.12% Na, TD 92142) from weaning to adulthood. Hemodynamic parameters such as cardiac output and total peripheral resistance, and the renal and lumbar sympathetic nerve activity were determined (n=45). Plasma renin activity, plasma and renal content of angiotensin (ANG) I and II, and the renal mRNA expression of angiotensinogen, renin, AT1 and AT2 receptors were also measured (n=24). Compared to normal- and low-salt diet-, high-salt-treated rats were hypertensive and developed an increase (P<0.05) in total peripheral resistance and lumbar sympathetic nerve activity. A decrease in renal renin and angiotensinogen-mRNAs and in plasma ANG II and plasma renin activity was also found in salt overloaded animals. The renal sympathetic nerve activity was higher (P<0.05) in low- compared to high-salt-treated rats, and was associated with an increase (P<0.05) in renal ANG I and II and with a decrease (P<0.05) in AT2 renal mRNA. Plasma ANG I and II and plasma renin activity were higher in low- than in normal-salt rats. Our results show that increased blood pressure is associated with increases in lumbar sympathetic nerve activity and total peripheral resistance in high-salt-treated rats. However, in low-salt-treated rats an increase in the renal sympathetic nerve was correlated with an increase in the renal content of ANG I and II and with a decrease in AT2 renal mRNA. These changes are probably in favor of the antinatriuretic response and the sodium homeostasis in the low-salt group. 相似文献