The remarkable regeneration capability of plant tissues or organs under culture conditions has underlain an extensive practice for decades. The initial step in plant in vitro regeneration often involves the induction of a pluripotent cell mass termed callus, which is driven by the phytohormone auxin and occurs via a root development pathway. However, the key molecules governing callus formation remain unknown. Here we demonstrate that Arabidopsis LATERAL ORGAN BOUNDARIES DOMAIN (LBD)/ASYMMETRIC LEAVES2-LIKE (ASL) transcription factors are involved in the control of callus formation program. The four LBD genes downstream of AUXIN RESPONSE FACTORs (ARFs), LBD16, LBD17, LBD18 and LBD29, are rapidly and dramatically induced by callus-inducing medium (CIM) in multiple organs. Ectopic expression of each of the four LBD genes in Arabidopsis is sufficient to trigger spontaneous callus formation without exogenous phytohormones, whereas suppression of LBD function inhibits the callus formation induced by CIM. Moreover, the callus triggered by LBD resembles that induced by CIM by characteristics of ectopically activated root meristem genes and efficient regeneration capacity. These findings define LBD transcription factors as key regulators in the callus induction process, thereby establishing a molecular link between auxin signaling and the plant regeneration program.
The plant hormone auxin plays a critical role in regulating various aspects of plant growth and development, and the spatial accumulation of auxin within organs, which is primarily attributable to local auxin biosynthesis and polar transport, is largely responsible for lateral organ morphogenesis and the establishment of plant architecture. Here, we show that three Arabidopsis INDETERMINATE DOMAIN (IDD) transcription factors, IDD14, IDD15, and IDD16, cooperatively regulate auxin biosynthesis and transport and thus aerial organ morphogenesis and gravitropic responses. Gain-of-function of each IDD gene in Arabidopsis results in small and transversally down-curled leaves, whereas loss-of-function of these IDD genes causes pleiotropic phenotypes in aerial organs and defects in gravitropic responses, including altered leaf shape, flower development, fertility, and plant architecture. Further analyses indicate that these IDD genes regulate spatial auxin accumulation by directly targeting YUCCA5 (YUC5), TRYPTOPHAN AMINOTRANSFERASE of ARABIDOPSIS1 (TAA1), and PIN-FORMED1 (PIN1) to promote auxin biosynthesis and transport. Moreover, mutation or ectopic expression of YUC suppresses the organ morphogenic phenotype and partially restores the gravitropic responses in gain- or loss-of-function idd mutants, respectively. Taken together, our results reveal that a subfamily of IDD transcription factors plays a critical role in the regulation of spatial auxin accumulation, thereby controlling organ morphogenesis and gravitropic responses in plants.
An experiment was conducted to estimate by simple linear regression the levels of endogenous amino acids in digesta collected from the distal ileum in pigs. Six barrows, average initial BW 35 kg, were fitted with a simple T-cannula at the distal ileum and fed six diets according to a 6 x 6 Latin square design. Six cornstarch-based diets containing six levels of CP from soybean meal (4, 8, 12, 16, 20, and 24% CP, respectively) were formulated. Chromic oxide (.4%) was included as the digestibility marker. Each experimental period consisted of 8 d. Ileal digesta were collected, at 2-h intervals, for a total of 24 h during d 7 and 8. There were linear relationships (P < .001) between dietary contents of apparent ileal digestible and total amino acids, irrespective of the ranges in graded dietary levels of amino acids. Determined with the regression technique, the endogenous levels of the indispensable amino acids (grams/kilogram of DMI) were as follows: arginine, .64; histidine, .23; isoleucine, .46; leucine, .69; lysine, .47; methionine, .13; phenylalanine, .31; threonine, .69; and valine, .54. Differences in the ranges of graded dietary levels of amino acids resulted in large differences in the estimated amounts of endogenous amino acids in ileal digesta. Furthermore, it seems that the levels of endogenous amino acids, as grams/kilogram of DMI, were constant at different dietary levels of amino acids, whereas the contributions of endogenous amino acids, as percentages of their dietary contents, decreased curvilinearly with increasing dietary contents. Therefore, apparent ileal digestibilities of amino acids were quadratically related to their dietary contents until plateau digestibilities were reached, whereas the true ileal digestibilities of amino acids were independent of their respective dietary contents. Furthermore, true ileal amino acid digestibilities should be determined from their corresponding plateau apparent ileal digestibilities. In conclusion, the levels of endogenous amino acids in ileal digesta can be determined reliably from the linear relationships between dietary contents of apparent ileal digestible and total amino acids. An important methodological consideration in the determination of endogenous amino acids by regression analysis is to design an appropriate range of graded dietary levels of amino acids.
Nautilus is the sole surviving externally shelled cephalopod from the Palaeozoic. It is unique within cephalopod genealogy and critical to understanding the evolutionary novelties of cephalopods. Here, we present a complete Nautilus pompilius genome as a fundamental genomic reference on cephalopod innovations, such as the pinhole eye and biomineralization. Nautilus shows a compact, minimalist genome with few encoding genes and slow evolutionary rates in both non-coding and coding regions among known cephalopods. Importantly, multiple genomic innovations including gene losses, independent contraction and expansion of specific gene families and their associated regulatory networks likely moulded the evolution of the nautilus pinhole eye. The conserved molluscan biomineralization toolkit and lineage-specific repetitive low-complexity domains are essential to the construction of the nautilus shell. The nautilus genome constitutes a valuable resource for reconstructing the evolutionary scenarios and genomic innovations that shape the extant cephalopods.
Objectives: Three hundred million people living with rare diseases worldwide are disproportionately deprived of in-time diagnosis and treatment compared with other patients. This review provides an overview of global policies that optimize development, licensing, pricing, and reimbursement of orphan drugs.Methods: Pharmaceutical legislation and policies related to access and regulation of orphan drugs were examined from 194 World Health Organization member countries and 6 areas. Orphan drug policies (ODPs) were identified through internet search, emails to national pharmacovigilance centers, and systematic academic literature search. Texts from selected publications were extracted for content analysis.Results: One hundred seventy-two drug regulation documents and 77 academic publications from 162 countries/areas were included. Ninety-two of 200 countries/areas (46.0%) had documentation on ODPs. Thirty-four subthemes from content analysis were categorized into 6 policy themes, namely, orphan drug designation, marketing authorization, safety and efficacy requirements, price regulation, incentives that encourage market availability, and incentives that encourage research and development. Countries/areas with ODPs were statistically wealthier (gross national income per capita = $10 875 vs $3950, P , .001). Country/area income was also positively correlated with the scope of the respective ODP (correlation coefficient = 0.57, P , .001).Conclusions: Globally, the number of countries with an ODP has grown rapidly since 2013. Nevertheless, disparities in geographical distribution and income levels affect the establishment of ODPs. Furthermore, identified policy gaps in price regulation, incentives that encourage market availability, and incentives that encourage research and development should be addressed to improve access to available and affordable orphan drugs.
Induction of a pluripotent cell mass termed callus is the first step in an in vitro plant regeneration system, which is required for subsequent regeneration of new organs or whole plants. However, the early molecular mechanism underlying callus initiation is largely elusive. Here, we analyzed the dynamic transcriptome profiling of callus initiation in Arabidopsis aerial and root explants and identified 1342 differentially expressed genes in both explants after incubation on callus-inducing medium. Detailed categorization revealed that the differentially expressed genes were mainly related to hormone homeostasis and signaling, transcriptional and post transcriptional regulations, protein phosphorelay cascades and DNA- or chromatin-modification. Further characterization showed that overexpression of two transcription factors, HB52 or CRF3, resulted in the callus formation in transgenic plants without exogenous auxin. Therefore, our comprehensive analyses provide some insight into the early molecular regulations during callus initiation and are useful for further identification of the regulators governing callus formation.
Mixed-linkage glucan (MLG) is a polysaccharide that is highly abundant in grass endosperm cell walls and present at lower amounts in other tissues. () and genes synthesize MLG, but it is unknown if other genes participate in the production and restructuring of MLG. Using transcriptional profiling data, we identified a trihelix family transcription factor () that is highly coexpressed with the gene (), which suggests that BdTHX1 is involved in the regulation of MLG biosynthesis. To determine the genes regulated by this transcription factor, we conducted chromatin immunoprecipitation sequencing (ChIP-seq) experiments using immature seeds and an anti-BdTHX1 polyclonal antibody. The ChIP-seq experiment identified the second intron of as one of the most enriched sequences. The binding of BdTHX1 to the intron sequence was confirmed using electrophoretic mobility shift assays (EMSA). ChIP-seq also showed that a gene encoding a grass-specific glycoside hydrolase family 16 endotransglucosylase/hydrolase () is bound by BdTHX1, and the binding was confirmed by EMSA. Radiochemical transglucanase assays showed that BdXTH8 exhibits predominantly MLG:xyloglucan endotransglucosylase activity, a hetero-transglycosylation reaction, and can thus produce MLG-xyloglucan covalent bonds; it also has a lower xyloglucan:xyloglucan endotransglucosylase activity. shoots regenerated from transformed calli overexpressing showed an abnormal arrangement of vascular tissue and seedling-lethal phenotypes. These results indicate that the transcription factor BdTHX1 likely plays an important role in MLG biosynthesis and restructuring by regulating the expression of and.
Enterovirus A71 (EV-A71) inactivated vaccines have been widely inoculated among children in Kunming City after it was approved. However, there was a large-scale outbreak of Enteroviruses (EVs) infection in Kunming, 2018.The epidemiological characteristics of HFMD and EVs were analyzed during 2008 to 2018, which are before and three years after EV-A71 vaccine starting to use. The changes of infection spectrum were also investigated, especially for severe HFMD in 2018.The incidence of EV-A71 decreased dramatically after EV-A71 vaccine starting use. The proportion of non CV-A16/EV-A71 EVs positive patients raised up to 77.17% to 85.82%, while, EV-A71 and CV-A16 only accounted for 3.41% to 7.24% and 6.94% to 19.42% in 2017 and 2018. CV-A6 was the most important causative agent in all clinical symptoms (Severe HFMD, HFMD, Herpangina and fever), accounting from 42.13% to 62.33%. EV-A71 only account for 0.36% to 2.05%. In sever HFMD, CV-A6 (62.33%), CV-A10 (11.64%), CV-A16 (10.96%) were the major causative agent in 2018. EV-A71 inactivated vaccine has a good protective effect against EV-A71 and induced EVs infection spectrum changefully. EV-A71 vaccine has no or insignificant cross-protection effect on CV-A6, CV-A10 and CV-A16. Herein, developing 4-valent combined vaccines is urgently needed.
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