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1.
Life (Basel) ; 14(4)2024 Apr 13.
Article in English | MEDLINE | ID: mdl-38672771

ABSTRACT

Harris Lines (HLs) are transverse, sclerotic lines that can be visualized by X-ray imaging and that occur in long bones, most commonly in the tibia and femur. HLs are associated with disrupted bone mineralization during endochondral ossification, affecting the normal growth process. The etiology of HLs is debated, with some claims linking their presence to detrimental factors such as inflammation, malnutrition, alcohol abuse, and diseases. The age at which HLs form can be estimated based on their location, which allows for a retrospective assessment of the individual's health status during childhood or youth. The current study is concerned with providing new equations to estimate the age of Harris Line occurrences using a simple calculating tool. Bone growth curves were derived based on a dataset provided by Byers in 1991 using non-linear estimation. The best model was chosen with the Akaike Information Criterion. New and old methods were compared through Bland-Altman plots. As a result, we managed to produce reliable, well-fitted growth curves, concordant with previous methods.

2.
Sci Total Environ ; 924: 171595, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38492585

ABSTRACT

Understanding the dynamics of tree recovery after drought is critical for predicting the state of tree growth in the context of future climate change. While there has been a great deal of researches showing that drought events can cause numerous significant negative effects on tree growth, the positive effects of post-drought wetting events on tree growth remain unclear. Therefore, we analyzed the effect of wet and dry events on the radial growth of trees in Central Asia using data on the width of tree rings. The results showed that 1) Drought is the main limiting factor for radial growth of trees in Central Asia, and that as the intensity and sensitivity of drought increases, tree resistance decreases and recovery rises, and more frequent droughts reduce tree resistance. 2) Tree radial growth varied significantly with wet and dry conditions, with wet events before and after drought events significantly enhancing tree radial growth. 3) When drought is followed by a wetting event, the relationship between tree resistance and recovery is closer to the "line of full resilience", with a significant increase in recovery, and compensatory growth is more likely to occur. Thus, wetting events have a significant positive effect on tree radial growth and are a key factor in rapid tree growth recovery after drought.


Subject(s)
Climate Change , Droughts , Forests
3.
Environ Pollut ; 348: 123850, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38548148

ABSTRACT

As emerging pollutants in the aquatic environments, micro- and nano-plastics (MNPs) aroused widespread environmental concerns for their potential threats to the ecological health. Previous research has proved that microalgae growth could recover from the MNPs toxicities, in which the extracellular polymeric substances (EPS) might play the key role. In order to comprehensively investigate the recovery process of microalgae from MNPs stress and the effecting mechanisms of EPS therein, this study conducted a series of experiments by employing two sizes (0.1 and 1 µm) of polystyrene (PS) MNPs and the marine model diatom Thalassiosira pseudonana during 14 days. The results indicated: the pigments accumulations and photosynthetic recovery of T. pseudonana under MPs exposure showed in the early stage (4-5 days), while the elevation of reactive oxygen species (ROS) and EPS contents lasted longer time period (7-8 days). EPS was aggregated with MNPs particles and microalgal cells, corresponding to the increased settlement rates. More increase of soluble (SL)-EPS contents was found than bound (B)-EPS under MNPs exposure, in which the increase of the protein proportion and humic acid-like substances in SL-EPS was found, thus facilitating aggregates formation. ROS was the signaling molecule mediating the overproduction of EPS. The transcriptional results further proved the enhanced EPS biosynthesis on the molecular level. Therefore, this study elucidated the recovery pattern of microalgae from MNPs stress and linked "ROS-EPS production changes-aggregation formation" together during the growth recovery process, with important scientific and environmental significance.


Subject(s)
Diatoms , Microalgae , Water Pollutants, Chemical , Polystyrenes/toxicity , Reactive Oxygen Species , Microplastics/toxicity , Extracellular Polymeric Substance Matrix , Water Pollutants, Chemical/toxicity , Plastics
4.
Int J Mol Sci ; 24(24)2023 Dec 11.
Article in English | MEDLINE | ID: mdl-38139187

ABSTRACT

Late spring cold is a disastrous weather condition that often affects early rice seedlings in southern China, limiting the promotion of direct seeding cultivation. However, there are few reports on the effect of these events and on the growth recovery mechanism of rice root systems after rice seedlings are exposed to this stress. This study selected the strong-growth-recovery variety B116 (R310/R974, F17) and the slow-recovery variety B811 (Zhonghui 286) for direct seeding cultivation and exposed them to low temperature and low-light stress to simulate a late spring cold event in an artificial climate chamber. The treatment consisted of 4 days of exposure to a day/night temperature of 14/10 °C and a light intensity of 266 µmol m-2s-1 while the control group was kept at a day/night temperature of 27/25 °C and light intensity of 533 µmol m-2s-1. The results showed that 6 days after stress, the total length, surface area, and volume of B116 roots increased by 335.5%, 290.1%, and 298.5%, respectively, while those of B811 increased by 228.8%, 262.0%, and 289.1%, respectively. In B116, the increase in root fresh weight was 223.1%, and that in B811 was 165.6%, demonstrating rapid root recovery after stress and significant differences among genotypes. The content of H2O2 and MDA in the B116 roots decreased faster than that in the B811 roots after normal light intensity and temperature conditions were restored, and the activity of ROS metabolism enzymes was stronger in B116 roots than in B811 roots. The correlation analysis between the transcriptome and metabolome showed that endogenous signal transduction and starch and sucrose metabolism were the main metabolic pathways affecting the rapid growth of rice seedling roots after exposure to combined stress from low temperature and low light intensities. The levels of auxin and sucrose in the roots of the strong-recovery variety B116 were higher, and this variety's metabolism was downregulated significantly faster than that of B811. The auxin response factor and sucrose synthesis-related genes SPS1 and SUS4 were significantly upregulated. This study contributes to an understanding of the rapid growth recovery mechanism in rice after exposure to combined stress from low-temperature and low-light conditions.


Subject(s)
Oryza , Seedlings , Seedlings/metabolism , Transcriptome , Oryza/metabolism , Temperature , Hydrogen Peroxide/metabolism , Indoleacetic Acids/metabolism , Metabolome , Sucrose/metabolism , Plant Roots/metabolism
5.
Dev Cell ; 58(18): 1657-1669.e5, 2023 09 25.
Article in English | MEDLINE | ID: mdl-37480843

ABSTRACT

Salt stress is one of the unfavorable environmental factors to affect plants. Salinity represses root growth, resulting in reduced biomass of agricultural plants. Little is known about how plants maintain root growth to counteract salt stress. The AP2-domain transcription factors PLETHORA1/2 (PLT1/2) act as master regulators in root meristem maintenance in Arabidopsis. In this study, we report that the salt overly sensitive (SOS) pathway component SOS2 regulates PLT1/2 at the post-transcriptional level. Salt-activated SOS2 interacts and phosphorylates PLT1/2 through their conserved C-terminal motifs to stabilize PLT1/2, critical for root apical meristem maintenance under salt stress. The phospho-mimetic version of PLT1/2 restored meristem and primary root length reduction of sos2-2 and plt1-4 plt2-2 mutants on salt treatment. Moreover, SOS2-mediated PLT1/2 phosphorylation improves root growth recovery after salt stress alleviation. We identify a SOS2-PLT1/2 core protein module that is required for protecting primary root growth and meristem maintenance from salt stress.


Subject(s)
Arabidopsis , Meristem , Signal Transduction , Arabidopsis/genetics , Phosphorylation , Salt Stress
6.
Front Plant Sci ; 14: 1133592, 2023.
Article in English | MEDLINE | ID: mdl-36875613

ABSTRACT

Low temperature and overcast rain are harmful to directly seeding early rice, it can hinder rice growth and lower rice biomass during the seedling stage, which in turn lowers rice yield. Farmers usually use N to help rice recuperate after stress and minimize losses. However, the effect of N application on the growth recovery for rice seedlings after such low temperature stress and its associated physiological changes remain unclearly. Two temperature settings and four post-stress N application levels were used in a bucket experiment to compare B116 (strong growth recovery after stress) with B144 (weak growth recovery). The results showed that the stress (average daily temperature at 12°C for 4 days) inhibited the growth of rice seedlings. Compared to the zero N group, the N application group's seedling height, fresh weight and dry weight significantly increased after 12 days. In particular, the increases in all three growth indicators were relatively higher than that of N application at normal temperature, indicating the importance of N application to rice seedlings after low temperature stress. The antioxidant enzyme activity of rice seedlings increased significantly after N application, which reduced the damaging effect of ROS (reactive oxygen species) to rice seedlings. At the same time, the soluble protein content of seedlings showed a slow decrease, while the H2O2 and MDA (malondialdehyde) content decreased significantly. Nitrogen could also promote nitrogen uptake and utilization by increasing the expression of genes related to NH 4 + and NO 3 - uptake and transport, as well as improving the activity of NR (nitrate reductase) and GS (glutamine synthetase) in rice. N could affect GA3 (gibberellin A3) and ABA (abscisic acid) levels by regulating the anabolism of GA3 and ABA. The N application group maintained high ABA levels as well as low GA3 levels from day 0 to day 6, and high GA3 levels as well as low ABA levels from day 6 to day 12. The two rice varieties showed obvious characteristics of accelerated growth recovery and positive physiological changes by nitrogen application after stress, while B116 generally showed more obvious growth recovery and stronger growth-related physiological reaction than that of B144. The N application of 40 kg hm-2 was more conducive to the rapid recovery of rice growth after stress. The above results indicated that appropriate N application promoted rice seedling growth recovery after low temperature stress mainly by increasing the activities of antioxidant enzymes and nitrogen metabolizing enzymes as well as regulating the levels of GA3 and ABA. The results of this study will provide a reference for the regulation of N on the recovery of rice seedling growth after low temperature and weak light stress.

7.
Sci Total Environ ; 878: 163132, 2023 Jun 20.
Article in English | MEDLINE | ID: mdl-37001651

ABSTRACT

The extensive radioactive fallout resulting from the 1986 Chornobyl accident caused tree death near the nuclear power plant and perturbed trees communities throughout the whole Chornobyl exclusion zone. Thirty years into the post-accident period, the radiation continues to exert its fatal effects on the surviving trees. However, to what extent the continuous multi-decadal radiation exposure has affected the radial tree growth and its sensitivity to climate variation remains unascertained. In this comparative study, we measure the Scots pine radial growth and quantify its response to climate at two sites along the western track of the nuclear fallout that received significantly different doses of radiation in 1986. The common features of the two sites allow us to disentangle and intercompare the effects of sub-lethal and moderate radiation doses on the pine's growth and climatic sensitivity. We extend the response function analysis by making the first use of the Full-Duration at Half-Maximum FDHM method in dendrochronology and apply the double-moving window approach to detect the main patterns of the growth-to-climate relationships and their temporal evolution. The stand exposed to sub-lethal radiation shows a significant radial growth reduction in 1986 with a deflection period of one year. The stand exposed to moderate radiation, in contrast, demonstrates no significant decrease in growth either in 1986 or in the following years. Beyond the radiation effects, the moving response function and FDHM enabled us to detect several mutual patterns in the growth-to-climate relationships, which are seemingly unrelated to the nuclear accident. To advance our predictive understanding of the response of forest ecosystems to a massive radioactive contamination, future studies should include quantitative wood anatomy techniques.


Subject(s)
Chernobyl Nuclear Accident , Pinus sylvestris , Ecosystem , Wood , Forests
8.
J Integr Plant Biol ; 65(1): 64-81, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36282494

ABSTRACT

Plants must adapt to the constantly changing environment. Adverse environmental conditions trigger various defensive responses, including growth inhibition mediated by phytohormone abscisic acid (ABA). When the stress recedes, plants must transit rapidly from stress defense to growth recovery, but the underlying mechanisms by which plants switch promptly and accurately between stress resistance and growth are poorly understood. Here, using quantitative phosphoproteomics strategy, we discovered that early ABA signaling activates upstream components of brassinosteroid (BR) signaling through CASEIN KINASE 1-LIKE PROTEIN 2 (CKL2). Further investigations showed that CKL2 interacts with and phosphorylates BRASSINOSTEROID INSENSITIVE1 (BRI1), the main BR receptor, to maintain the basal activity of the upstream of BR pathway in plants exposed to continuous stress conditions. When stress recedes, the elevated phosphorylation of BRI1 by CKL2 contributes to the swift reactivation of BR signaling, which results in quick growth recovery. These results suggest that CKL2 plays a critical regulatory role in the rapid switch between growth and stress resistance. Our evidence expands the understanding of how plants modulate stress defense and growth by integrating ABA and BR signaling cascades.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Abscisic Acid/metabolism , Brassinosteroids/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Signal Transduction
9.
Plant Cell Environ ; 45(10): 2923-2942, 2022 10.
Article in English | MEDLINE | ID: mdl-35906186

ABSTRACT

Signalling roles of hydrogen sulphide (H2 S) in stress biology are widely reported but not sufficiently established to urge its use in agronomic practice. Our lack of quantitative understanding of the metabolic rewiring in H2 S signalling makes it difficult to elucidate its functions in stress tolerance on the biochemical level. Here, Malus hupehensis Rehd. var. pingyiensis seedlings were first treated with salt stress for 2 weeks and then treated with four different concentrations of NaHS. Through vigorous investigations, including phenotypic analysis, 13 C transient labelling and targeted metabolic and transcriptomic analysis, for the first time in the seedlings of a woody fruit crop, we found out that H2 S recycles fixed carbons through glycolysis and tricarboxylic acid cycle to inhibit the futile accumulation of carbohydrates, to maintain an efficient CO2 assimilation, to keep a balanced starch metabolism, to produce sufficient H2 O2 , to maintain malate/γ-aminobutyric acid homeostasis via an H2 O2 -induced anion channel (aluminium-activated malate transporter) and eventually to improve salt-stress recovery. Our results systematically demonstrate the vital roles of central carbon metabolism in H2 S signalling and clarify the mode of action of H2 S in apple seedlings. We conclude that H2 S signalling interacts with central carbon metabolism in a bottom-up manner to recover plant growth after salt stress.


Subject(s)
Malus , Carbon/metabolism , Malates/metabolism , Malus/genetics , Malus/metabolism , Salt Stress , Seedlings/metabolism
10.
Appl Biochem Biotechnol ; 194(12): 5748-5766, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35819692

ABSTRACT

To overcome the limited resistance to alcohol stress, genetically engineered Synechocystis sp. PCC 6803 strains with overexpressions of genes related with the ROS detoxification system (sodB and gpx2, which encode superoxide dismutase and glutathione peroxidase, respectively) were developed. Three engineered strains including a sodB-overexpressing strain (OE + S), a gpx2-overexpressing strain (OE + G), and a sodB/gpx2-overexpressing strain (OE + SG) grew similarly as wild-type control under normal condition. When compared to wild-type control, OE + S and OE + SG strains grew faster for 4 days under 2.0% (v/v) ethanol and 0.3% (v/v) n-butanol conditions, as well as having higher chlorophyll a levels. On the other hand, the prominent growth recovery of OE + G and OE + SG was noted within 4 days in normal BG11 medium after treating cells with high alcohol stresses for 1 h, in particular 15% ethanol and 2.5% n-butanol. Under 4 days of recovery from butanol stress, specific levels of intracellular pigments including chlorophyll a and carotenoids were dramatically increased in all modified strains. The overexpression of antioxidant genes then revealed a significant improvement of alcohol tolerance in Synechocystis sp. PCC 6803.


Subject(s)
Synechocystis , Synechocystis/genetics , Chlorophyll A , 1-Butanol , Bacterial Proteins/genetics , Ethanol
11.
Child Abuse Negl ; 123: 105388, 2022 01.
Article in English | MEDLINE | ID: mdl-34801849

ABSTRACT

BACKGROUND: Psychosocial short stature (PSS) is a rare disorder associated with emotional deprivation. Growth recovery lines (GRLs), the radiodense bands in metaphyseal bones, are indicators of stress. OBJECTIVE: To evaluate the efficacy of using GRLs in the distal radius to identify PSS. PARTICIPANTS AND SETTING: This retrospective cohort study included children 15-138 months of age with short stature whose hands and wrists were radiographed between 2011 and 2020 at Matsuyama Red Cross Hospital in Japan. METHODS: PSS was determined if a child with short stature had been reported to be abused or neglected. Other pathological short statures were diagnosed per the established criteria. GRLs, height velocity before and after specific treatment, insulin-like growth factor 1, and the difference between chronological and skeletal age were assessed. RESULTS: The PSS and other short stature groups comprised of 7 and 11 children, respectively. The body mass index of the PSS group was smaller than that of other short stature group (-1.15 standard deviation [SD] vs. 0.57 SD, P = 0.003). The PSS group had significantly more GRLs than the other group (5.3 vs. 0.5, P = 0.011). Height velocity before treatment in the PSS group was significantly lower (-5.46 SD vs. -1.86 SD, P = 0.005), with no significant differences in other variables. The specificity for PSS was >90% when children with short stature had at least three GRLs in both distal radii. CONCLUSIONS: Abuse or neglect should be considered in children with short stature having multiple GRLs in the distal radius.


Subject(s)
Child Abuse , Child Behavior Disorders , Dwarfism , Body Height , Child , Humans , Retrospective Studies
12.
Cell Cycle ; 19(23): 3375-3385, 2020 12.
Article in English | MEDLINE | ID: mdl-33225802

ABSTRACT

We recently made an important discovery that radiation induces myofibroblasts, which play a role in radiation-related carcinogenesis via tumor microenvironment formation. Here, we investigated the threshold dose and the mechanisms of myofibroblast induction to assess adverse radiation effects on normal cells. Single-dose of healthy human fibroblasts in vitro promotes myofibroblast induction at high doses (≥ 5 Gy). In contrast, repeated low dose of fractionated radiation is at least equivalent to high-dose single radiation regarding myofibroblast induction. ROS play a pivotal role in the process of myofibroblast induction in normal tissue injury. Antioxidants, such as epicatechin and ascorbic acid can prevent myofibroblast induction by scavenging ROS. We further investigated the role of DNA damage responses (DDR) on myofibroblast induction. Blocking the DDR using DNA-PK or AKT inhibitors enhanced cellular sensitivity to radiation and facilitated myofibroblast induction, whereas an ATM inhibitor also enhanced radiation sensitivity but abrogated ROS accumulation and myofibroblast induction. In contrast to standard culture conditions, myofibroblasts remained after low or moderate doses of radiation (below 2.5 Gy) under growth-restricted conditions. In conclusion, the recovery of damaged cells from radiation is essential for myofibroblast clearance, which restores stromal cell dormancy and prevents tumor microenvironment formation. However, residual ROS, by way of sustaining myofibroblast presence, can facilitate tumor microenvironment formation. Targeting ROS using antioxidants is effective in the mitigation of radiation-related adverse effects, such as growth retardation and myofibroblast induction, and helps protect normal tissues.


Subject(s)
Myofibroblasts/metabolism , Myofibroblasts/radiation effects , Radiation Dosage , Antioxidants/pharmacology , Cell Line , DNA Damage/drug effects , DNA Damage/physiology , DNA Damage/radiation effects , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/radiation effects , Humans , Myofibroblasts/drug effects , Reactive Oxygen Species/metabolism
13.
Dev Cell ; 55(3): 367-380.e6, 2020 11 09.
Article in English | MEDLINE | ID: mdl-32891194

ABSTRACT

Plant stress responses involve dynamic growth regulation. Growth is restricted in harsh environmental conditions and is rapidly restored when conditions improve. Here, we identified BIN2, a glycogen synthase kinase 3 (GSK3)-like kinase, as a molecular switch in the transition to robust growth after salt stress in Arabidopsis thaliana. In the rapid recovery phase after salt stress, the calcium sensors SOS3 and SCaBP8 perceive a calcium signal and promote BIN2 localization to the plasma membrane to repress the salt stress response, and BIN2 inhibits SOS2 activity and enhances growth by releasing BZR1/BES1 transcriptional activity. The expression of stress- and brassinosteroid-responsive genes is coordinately regulated during this process. bin2-3bil1 and bin2-3bil2 mutants defective in BIN2 and its homologs BIL1 and BIL2, respectively, are hyposensitive to salt stress. Our study suggests that salt signaling modulates the subcellular localization and interactions of BIN2. By phosphorylating different substrates, BIN2 regulates the salt stress response and growth recovery.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/enzymology , Arabidopsis/growth & development , Glycogen Synthase Kinase 3/metabolism , Protein Kinases/metabolism , Salt Stress , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Gene Expression Regulation, Plant , Homeostasis , Models, Biological , Phosphorylation , Phosphothreonine/metabolism , Protein Binding , Protein Kinases/genetics
14.
Pediatr Radiol ; 50(2): 207-215, 2020 02.
Article in English | MEDLINE | ID: mdl-31522259

ABSTRACT

BACKGROUND: Growth recovery lines are radiodense lines in long bones reported to be indicators of stress. OBJECTIVE: The purpose of this study was to understand the distribution, quantity and associations of growth recovery lines in children ages 0-24 months with high and low risk for child maltreatment. MATERIALS AND METHODS: We conducted a retrospective cohort study of children ages 0-24 months who had skeletal surveys and an assessment for maltreatment. Growth recovery lines, fractures and osteopenia were assessed independently by two pediatric radiologists blinded to the abuse likelihood. RESULTS: Of the 135 children in this study, 58 were in the low-risk group, 26 were in the neglect group, and 51 were in the physical abuse group. Children in the neglected and physically abused groups had 1.73 times (95% confidence interval [CI] of 1.16, 2.59), P=0.007) and 1.84 times (95% CI 1.28, 2.63, P<0.001) more growth recovery lines than the low-risk group, respectively. Growth recovery lines occurred at an earlier age in the neglect group (age interaction P=0.03) and abuse group (age interaction P=0.01) compared to the low-risk group. The specificity for maltreatment in children with at least 10 growth recovery lines in the long bones was greater than 84%, while sensitivity was less than 35%. The most common locations for growth recovery lines were distal radius, proximal tibia and distal tibia. CONCLUSION: In the absence of a known major stressor, physical abuse and neglect should be considered in children younger than 24 months with at least 10 growth recovery lines.


Subject(s)
Bone Development , Bone and Bones/diagnostic imaging , Child Abuse/diagnosis , Radiography/methods , Age Factors , Child, Preschool , Cohort Studies , Female , Humans , Infant , Infant, Newborn , Male , Retrospective Studies , Risk Assessment , Sensitivity and Specificity
15.
Mech Dev ; 156: 32-40, 2019 04.
Article in English | MEDLINE | ID: mdl-30936002

ABSTRACT

Whether the growth of embryos after a period of stunt becomes accelerated (Catch-Up Growth, CUGr), as it occurs postnatally, has rarely been examined experimentally in any class of animals. Here, hypoxia or cold of different degrees and durations caused growth retardation in chicken embryos during the first or second week of incubation. On average, on the day of removal of the growth-inhibition, the weight of the experimental groups was 73% (wet) and 61% (dry) of control embryos, while near end-incubation (embryonic day E18) their weight averaged significantly more, respectively, 80% and 84% of controls (P < 0.001). When compared as function of developmental time, the post-intervention growth of experimental embryos was faster than that of controls. The faster growth was fully accounted for by their smaller weight at end-intervention, because embryonic growth is higher the smaller the weight. Hence, their growth was appropriate for their weight, rather than for their age. In fact, out of eight different models of growth based on age and weight (wet or dry) in various combination, the model based on embryonic wet weight at end-intervention, and weight alone, was the best predictor of the embryo's post-intervention growth. The oxygen consumption of the experimental embryos during CUGr was appropriate for their weight. In conclusion, in this experimental model of CUGr, the embryo's weight at the end of a stunt could fully predict and explain the rate of growth during the post-intervention recovery period.


Subject(s)
Chickens/growth & development , Embryonic Development/genetics , Oxygen Consumption/genetics , Animals , Chick Embryo , Chickens/genetics , Cold Temperature/adverse effects , Hypoxia/genetics
16.
Genes Cells ; 23(5): 357-369, 2018 May.
Article in English | MEDLINE | ID: mdl-29542212

ABSTRACT

ppGpp, an alarmone for stringent response, plays an important role in the reprogramming of the transcription complex at the time of stress. In Escherichia coli, ppGpp mediates its action by binding to at least two different sites on RNA polymerase (RNAP). One of the sites to which ppGpp binds to RNAP is at the ß'-ω interface; however, the underlying molecular mechanism and the physiological relevance of ppGpp binding to this site remain unclear. In this study, we have performed UV cross-linking experiments using 32 P azido-labeled ppGpp to probe its association with RNAP in the absence and presence of ω, and observed weaker binding of ppGpp to the RNAP without ω. Furthermore, we followed the binding kinetics of ppGpp to RNAP with and without ω by isothermal titration calorimetry and found it to be concurrent with the cross-linking results. Native ω is intrinsically disordered, and we have used a previously characterized structured mutant of ω, which affects the plasticity of the active site of RNAP. Results show that the flexibility conferred by the unstructured ω is a prerequisite for ppGpp binding to RNAP. We have analyzed the stress-associated phenotypes in an E. coli strain devoid of ω (∆rpoZ). ppGpp levels in ∆rpoZ strain were found to be similar to that of the wild-type strain. Interestingly, when the ∆rpoZ strain of E. coli was transferred after nutritional stress to an enriched media, the recovery of growth was compromised. We have identified a new phenotype of ∆rpoZ strain corresponding to defect in biofilm formation in minimal media.


Subject(s)
Biofilms/growth & development , DNA-Directed RNA Polymerases/metabolism , Escherichia coli Proteins/metabolism , Escherichia coli/growth & development , Gene Expression Regulation, Bacterial , Guanosine Tetraphosphate/metabolism , Binding Sites , Catalytic Domain , Culture Media , DNA-Directed RNA Polymerases/genetics , Escherichia coli/enzymology , Escherichia coli/genetics , Kinetics , Lipids/analysis , Protein Binding , Protein Subunits , Stress, Physiological , Transcription, Genetic
17.
Soc Sci Med ; 179: 81-90, 2017 04.
Article in English | MEDLINE | ID: mdl-28260638

ABSTRACT

Child chronic undernutrition, as measured by stunting, is prevalent in low- and middle-income countries and is among the major threats to child development. While stunting and its implications for cognitive development have been considered irreversible beyond early childhood there is a lack of consensus in the literature on this, as there is some evidence of recovery from stunting and that this recovery may be associated with improvements in cognition. Less is known however, about the drivers of growth recovery and the aspects of recovery linked to cognitive development. In this paper we investigate the factors associated with growth recovery and faltering through age 12 years and the implications of the incidence, timing, and persistence of post-infancy recovery from stunting for cognitive development using longitudinal data from Ethiopia, India, Peru, and Vietnam. We find that the factors most systematically associated with accelerated growth both before and after early childhood and across countries include mother's height, household living standards and shocks, community wages, food prices, and garbage collection. Our results suggest that post-infancy recovery from stunting is more likely to be systematically associated with higher achievement scores across countries when it is persistent and that associations between growth trajectories and cognitive achievement in middle childhood do not persist through early adolescence across countries. Overall, our findings indicate that growth after early childhood is responsive to changes in the household and community environments and that growth promotion after early childhood may yield improvements in child cognitive development.


Subject(s)
Aptitude Tests , Body Height , Child Development , Child Nutrition Disorders/epidemiology , Child Nutrition Disorders/physiopathology , Developing Countries/statistics & numerical data , Adolescent , Age Factors , Birth Order , Child , Child, Preschool , Environment , Food Supply/statistics & numerical data , Humans , Income/statistics & numerical data , Infant , Sanitation/statistics & numerical data , Sex Factors , Socioeconomic Factors
18.
J Nutr ; 146(7): 1387-93, 2016 07.
Article in English | MEDLINE | ID: mdl-27306894

ABSTRACT

BACKGROUND: Recent research has highlighted the need for additional studies on the nutrition input required to stabilize growth. OBJECTIVE: Our objective was to examine the association between dietary diversity and conditional growth in children aged 0-89 mo. METHODS: We analyzed cohort data from 529 mothers and children living in a remote and food-insecure region in the mountains of Nepal. Children were aged 0-59 mo at baseline and were followed up after 9 and 29 mo. Conditional growth was calculated as the deviation from the expected height-for-age difference (HAD) trajectory based on previous measures of HAD and the pattern of growth in the population. Dietary diversity was assessed with the use of a count of the foods consumed from 7 food groups in the previous 7 d. The association between dietary diversity and conditional growth during the 2 follow-up periods (of 9 and 20 mo, respectively) was estimated with the use of ordinary least-squares regressions. RESULTS: Prevalence of stunting and absolute height deficits was very high and increased over the course of the study. At the last measurement (age range 29-89 mo), 76.5% were stunted and the mean ± SD HAD was -11.7 ± 4.6 cm. Dietary diversity was associated positively with conditional growth in the later (May 2012-December 2013) but not the earlier (July 2011-May 2012) growth period. Children's ages ranged from 0 to 59 mo in July 2011, 9 to 69 mo in May 2012, and 29 to 89 mo in December 2013. After adjustment, increasing the dietary diversity by one food group was associated with a 0.09 cm (95% CI: 0.00, 0.17 cm) increase in conditional growth in the second growth period. CONCLUSIONS: Increasing dietary diversity for children reduces the risk of stunting and improves growth after growth faltering. Future efforts should be directed at enabling families in food-insecure areas to feed their children a more diverse diet.


Subject(s)
Body Height , Growth Disorders/epidemiology , Child , Child Nutrition Disorders/epidemiology , Child Nutritional Physiological Phenomena , Child, Preschool , Diet , Diet Surveys , Female , Humans , Infant , Infant Nutrition Disorders/epidemiology , Infant, Newborn , Male , Nepal/epidemiology
19.
Pediatr Radiol ; 46(9): 1275-81, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27147078

ABSTRACT

BACKGROUND: Growth recovery lines, also known as growth arrest lines, are transverse radiodense metaphyseal bands that develop due to a temporary arrest of endochondral ossification caused by local or systemic insults. OBJECTIVE: To determine if growth recovery lines are more common in infants at high risk versus low risk for abuse. MATERIALS AND METHODS: Reports of American College of Radiology compliant skeletal surveys (1999-2013) were reviewed with clinical records. Infants at low risk for abuse had a skull fracture without significant intracranial injury, history of a fall and clinical determination of low risk (child protection team/social work assessment). Infants at high risk had significant intracranial injury, retinal hemorrhages, other skeletal injuries and clinical determination of high risk. There were 52 low-risk infants (mean: 4.7 months, range: 0.4-12 months) and 21 high-risk infants (mean: 4.2 months, range: 0.8-9.1 months). Two blinded radiologists independently evaluated the skeletal survey radiographs of the knees/lower legs for the presence of at least one growth recovery line. RESULTS: When growth recovery lines are scored as probably present or definitely present, their prevalence in the low-risk group was 38% (standard deviation [SD] = 8%; reader 1 = 17/52, reader 2 = 23/52) vs. 71% (SD = 7%; reader 1 = 16/21, reader 2 = 14/21) in the high-risk group (P < 0.001; odds ratio 4.0, 95% CI: 1.7-9.5). CONCLUSION: Growth recovery lines are encountered at a significantly higher rate in infants at high risk vs. low risk for abuse. This suggests that abused infants are prone to a temporary disturbance in endochondral ossification as a result of episodic physiological stresses.


Subject(s)
Bone and Bones/diagnostic imaging , Bone and Bones/injuries , Child Abuse/diagnosis , Leg Injuries/diagnostic imaging , Diagnosis, Differential , Female , Humans , Infant , Male
20.
Food Microbiol ; 46: 515-520, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25475323

ABSTRACT

In this work, the development of resistance and the recovery of growth after several consecutive cycles of high hydrostatic pressure (HPP) were for the first time evaluated in different strains of Staphylococcus aureus. Three strains of this important and highly resilient to HPP foodborne pathogen were used: a non-enterotoxigenic ATCC 6538 strain, treated with 600 MPa for 30 min at 20 °C, and the toxigenic strains 2153 MA (with enterotoxin A) and 2065 MA (with the enterotoxins A, G and I), treated with 600 MPa for 15 min at 20 °C. After the first treatment, surviving colonies were used to produce new bacterial cultures. This procedure was repeated nine times more for each bacterium or until total inactivation occurred. The inactivation profile of non-enterotoxic strain and the two enterotoxic strains did not change after consecutive cycles, but the toxic strain with three enterotoxins was completely inactivated after the fourth cycle. The three strains did not recover their viability after 14 days. The results indicate that HPP effectively inactivates non-toxigenic and toxigenic strains of S. aureus after a single treatment. The surviving bacteria did not develop resistance after 10 cycles of pressurization and did not recover their viability after 14 days of incubation.


Subject(s)
Hydrostatic Pressure , Staphylococcus aureus/chemistry , Staphylococcus aureus/growth & development , Enterotoxins/metabolism , Food Microbiology , Microbial Viability , Staphylococcus aureus/classification , Staphylococcus aureus/metabolism
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