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161.
Carbamoylphosphate synthetase (CPS) catalyzes the first committed step in
pyrimidine biosynthesis, arginine biosynthesis, or the urea cycle.
Organisms may contain either one generalized or two specific CPS enzymes,
and these enzymes may be heterodimeric (encoded by linked or unlinked
genes), monomeric, or part of a multifunctional protein. In order to help
elucidate the evolution of CPS, we have performed a comprehensive
phylogenetic analysis using the 21 available complete CPS sequences,
including a sequence from Sulfolobus solfataricus P2 which we report in
this paper. This is the first report of a complete CPS gene sequence from
an archaeon, and sequence analysis suggests that it encodes an enzyme
similar to heterodimeric CPSII. We confirm that internal similarity within
the synthetase domain of CPS is the result of an ancient gene duplication
that preceded the divergence of the Bacteria, Archaea, and Eukarya, and use
this internal duplication in phylogenetic tree construction to root the
tree of life. Our analysis indicates with high confidence that this
archaeal sequence is more closely related to those of Eukarya than to those
of Bacteria. In addition to this ancient duplication which created the
synthetase domain, our phylogenetic analysis reveals a complex history of
further gene duplications, fusions, and other events which have played an
integral part in the evolution of CPS.
相似文献
162.
López-Valenzuela BE Armenta-Bojórquez AD Hernández-Verdugo S Apodaca- Sánchez MA Samaniego-Gaxiola JA Valdez-Ortiz A 《Phyton》2019,88(1):37-46
Microbes that are beneficial to plants are used to
enhance the crop growth, yield and are alternatives to chemical
fertilizers. Trichoderma and Bacillus are the predominant plant
growth-promoting fungi and bacteria. The objective of this study
was select, characterize, and evaluate isolates of Trichoderma
spp. and Bacillus spp. native from the northern region of Sinaloa,
Mexico, and assess their effect on growth promotion in maize (Zea
mays L.). In greenhouse conditions, four Trichoderma isolates and
twenty Bacillus isolates, as well as two controls, were tested in a
completely randomized design with three replicates. We selected
the two best strains of Trichoderma and Bacillus: TB = Trichoderma
asperellum, TF = Trichoderma virens, B14 = Bacillus cereus sensu
lato and B17 = Bacillus cereus, which were evaluated in the field in
a completely randomized blocks in factorial arrangement design
with three replicates applying different rates of nitrogen fertilizer
(0, 150 kg N/ha, and 300 kg N/ha). Treatments 5 (B17 = B. cereus)
and 11 (TF = T. virens) both fertilized with 150 kg N/ha showed
similar yields and they did not reveal significant differences from
the treatments fertilized with 300 kg N/ha. This indicated that
treatment 5 (B17= B. cereus with 150 kg N/ha) and treatment
11 (TF= T. virens with 150 kg N/ha) were efficient as growth
promoters, by not showing significant differences in root volume
and dry weight of foliage. The results indicated a reduction of 50%
in the rate of nitrogen to fertilizer required for maize (Zea mays
L.) crops. These microorganisms Trichoderma and Bacillus could
be an alternative to reduce the use of chemical fertilizers in maize. 相似文献
163.
HE Gruber E Marrero JA Ingram GL Hoelscher EN Hanley Jr 《Biotechnic & histochemistry》2017,92(3):222-229
The importance of cytokines in disc degeneration is well recognized. Little is known about IL-22 expression in the human intervertebral disc. We investigated IL-22 immuno-localization in disc tissue, and molecular expression and production of IL-22 by annulus cells cultured in three-dimensional (3D) culture. We examined human disc tissue using immunohistochemistry and we cultured isolated annulus cells in 3D to analyze IL-22 expression and production, and its receptor, IL-22R, in conditioned media. Ingenuity pathway analysis (IPA) also was used to identify significant gene expression networks within the molecular data. IL-22 and IL-22R were immunolocalized in many cells in the human outer and inner annulus; fewer cells exhibited localization in the nucleus. Three-dimensional culture of annulus cells demonstrated production of IL-22 in conditioned media; exposure to IL-1ß or TNF-α significantly reduced IL-22 levels. Significant decreases also were identified in conditioned media assayed for IL-22R in TNF-α treated cells. IPA analysis showed that IL-22 ranked among the top canonical pathways. We found constitutive expression and production of IL-22 and IL-22R in the disc, which expands our understanding of the effect of pro-inflammatory cytokines on IL-22 expression and production. Three-dimensional cultured annulus cells exposed to IL-1ß or TNF produced significantly lower levels of IL-22 into their conditioned media compared to levels produced by control cells. Our findings have clinical relevance because of the elevated pro-inflammatory milieu within the degenerating human disc. 相似文献
164.
The segregation of laboratory maintained male and larval Myrmecia gulosa from workers resulted in increased levels of culturable microbiota. After 29 days, microbial levels recovered from segregated males and larvae were 27 and 126 times greater than from males and larvae not segregated from workers. These findings are consistent with the hypothesis that metapleural gland secretions, absent in larvae and males, are transferred from workers to larvae, and males contribute to the inhibition of cuticular microbiota. 相似文献
165.
Synthetic sheep urine additions (59 g N m−2) were made to pastures on two soils, at Fasset, a semi-natural grassland, and Strathfinella, an improved pasture. Urine was
applied to microplots in May and the soil, grass and soil solution analyzed 1, 2, 4, 5, 12 and 23 weeks after the addition.
At Fasset, the grass was scorched by urine and the standing biomass decreased compared to the control, increasing only after
5 weeks. The absence of scorching at the Strathfinella site was attributed to a greater biomass of root mat to buffer the
roots from exposure to NH3and a greater rainfall immediately following treatment. Scorching reduced the uptake of N and it was not clear if the greater
contents of NH4
+ and the increases in soil pH at Fasset compared with Strathfinella were the causes or symptoms of the scorch effect. Amounts
of extractable organic N (DON) were similar in both soils and increased during the first 4 weeks and then decreased. Urine
addition both increased and decreased DON at different times, but the overall mean values were unchanged. Urine application
changed the distribution of P in the two soils, increasing the soil solution P at Fasset by 80 mg P m−2 and raising the P content of herbage at Strathfinella by 600 mg P m−2. In the soil solution, dissolved forms of molybdate reactive P, organic P and condensed P fractions were all increased by
the urine addition. After 23 weeks, condensed P made the greatest contribution to soil solution P in both soils indicating
that this fraction was the least available for plant uptake.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
166.
Yescas CP MA Segura C L Martínez C VP Álvarez R JA Montemayor T JA Orozco V JE Frías R 《Phyton》2015,84(2):272-279
The scarcity of water in arid and semiarid regions of the world is a problem that every day increases by climate change. The subsurface drip irrigation (SDI) and changes in population density of plants are alternatives that can be used to make a sustainable use of water. Therefore, the objectives of this study were to determine the combination that allows for an increased corn performance and efficient use of water without losing the quality of forage. Three different irrigation levels were applied through a system of a SDI at three different densities of forage maize plants in an arid region. The results demonstrated that by applying different levels of water, either enough or lack of soil moisture is created, which is directly reflected in crop yield, and its determining variables such as green forage and dry matter yield, and nutritional quality. The irrigation level to a 100% of potential evapotranspiration (PET), at a density of 80000 plants/ha, increased yield of green forage to 57664 kg/ha; crude protein was 8.59%, while the rest of the quality parameters decreased. This study allowed to conclude that the irrigation level was the major factor in the response of the crop. 相似文献
167.
Proteins are one of the major metabolites in biomass from microalgae that constitute the diet of marine organisms grown in aquaculture, and are essential for their growth. The quantity of this component is influenced by nutrients, temperature and light intensity, among others. We examined the growth, biomass production and protein of Chaetoceros muelleri with two sources of nitrogen (nitrate and urea) at three concentrations, using the medium f/2 (0.88 mol/L) (nitrates) as control. The treatments were the medium 2f (3.53 mol/L) and 4f (7.05 mol/L) with NO3-, and the medium f/2 (0.88 mol/L), 2f (3.53mol/L) and 4f (7.05 mol/L) with urea. In general, the productive parameters were greater using urea than nitrate in the media. Higher cell concentrations (2.83 x 106 cell/mL), average and cumulative growth rates (1.50 div/day and 6.01 divisions), dry weight (0.0044 g/L), and proportion of proteins (23.74%) were found when urea was used as the N source. However, most of the bands on the electrophoretic profile were present in the mediums with NO3- (~6.5 to 90 kDa). 相似文献
168.
Opportunities for mobilizing recalcitrant phosphorus from agricultural soils: a review 总被引:3,自引:0,他引:3
Daniel Menezes-Blackburn Courtney Giles Tegan Darch Timothy S. George Martin Blackwell Marc Stutter Charles Shand David Lumsdon Patricia Cooper Renate Wendler Lawrie Brown Danilo S. Almeida Catherine Wearing Hao Zhang Philip M. Haygarth 《Plant and Soil》2018,427(1-2):5-16
Background
Phosphorus (P) fertilizer is usually applied in excess of plant requirement and accumulates in soils due to its strong adsorption, rapid precipitation and immobilisation into unavailable forms including organic moieties. As soils are complex and diverse chemical, biochemical and biological systems, strategies to access recalcitrant soil P are often inefficient, case specific and inconsistently applicable in different soils. Finding a near-universal or at least widely applicable solution to the inefficiency in agricultural P use by plants is an important unsolved problem that has been under investigation for more than half a century.Scope
In this paper we critically review the strategies proposed for the remobilization of recalcitrant soil phosphorus for crops and pastures worldwide. We have additionally performed a meta-analysis of available soil 31P–NMR data to establish the potential agronomic value of different stored P forms in agricultural soils.Conclusions
Soil inorganic P stocks accounted on average for 1006 ± 115 kg ha?1 (57 ± 7%), while the monoester P pool accounted for 587 ± 32 kg ha?1 (33 ± 2%), indicating the huge potential for the future agronomic use of the soil legacy P. New impact driven research is needed in order to create solutions for the sustainable management of soil P stocks.169.
The plasma propranolol levels associated with the abolition of chronic, stable ventricular ectopic beats have been studied. Racemic propranolol (DL) suppressed the ectopic foci at plasma levels of 40-85 ng/ml in eight patients, but levels of 70-200 ng/ml were unsuccessful in four patients. Dextro-(D) propranolol levels of 180-310 ng/ml were ineffective in four patients who had previously responded at levels of 60-75 ng/ml of racemic propranolol. The significance of the sympathetic nervous system in the genesis of ectopic beats is discussed. It is concluded that propranolol is clinically effective by virtue of its beta-adrenergic blocking activity. 相似文献
170.