Karyotyping of aneuploid and polyploid plants from low coverage whole-genome resequencing.

BACKGROUND: Karyotype, as a basic characteristic of species, provides valuable information for fundamental theoretical research and germplasm resource innovation. However, traditional karyotyping techniques, including fluorescence in situ hybridization (FISH), are challenging and low in efficiency, especially when karyotyping aneuploid and polyploid plants. The use of low coverage whole-genome resequencing (lcWGR) data for karyotyping was explored, but existing methods are complicated and require control samples. RESULTS: In this study, a new protocol for molecular karyotype analysis was provided, which proved to be a simpler, faster, and more accurate method, requiring no control. Notably, our method not only provided the copy number of each chromosome of an individual but also an accurate evaluation of the genomic contribution from its parents. Moreover, we verified the method through FISH and published resequencing data. CONCLUSIONS: This method is of great significance for species evolution analysis, chromosome engineering, crop improvement, and breeding.

Downregulation of the expression of subgenomic chromosome A7 genes promotes plant height in resynthesized allopolyploid Brassica napus.

KEY MESSAGE: Homoeolog expression bias and the gene dosage effect induce downregulation of genes on chromosome A7, causing a significant increase in the plant height of resynthesized allopolyploid Brassica napus. Gene expression levels in allopolyploid plants are not equivalent to the simple average of the expression levels in the parents and are associated with several non-additive expression phenomena, including homoeolog expression bias. However, hardly any information is available on the effect of homoeolog expression bias on traits. Here, we studied the effects of gene expression-related characteristics on agronomic traits using six isogenic resynthesized Brassica napus lines across the first ten generations. We found a group of genes located on chromosome A7 whose expression levels were significantly negatively correlated with plant height. They were expressed at significantly lower levels than their homoeologous genes, owing to allopolyploidy rather than inheritance from parents. Homoeolog expression bias resulted in resynthesized allopolyploids with a plant height similar to their female Brassica oleracea parent, but significantly higher than that of the male Brassica rapa parent. Notably, aneuploid lines carrying monosomic and trisomic chromosome A7 had the highest and lowest plant heights, respectively, due to changes in the expression bias of homoeologous genes because of alterations in the gene dosage. These findings suggest that the downregulation of the expression of homoeologous genes on a single chromosome can result in the partial improvement of traits to a significant extent in the nascent allopolyploid B. napus.

The ethylene glycol-mediated sol-gel synthesis of nano AlF3: structural and acidic properties after different post treatments.

In this work, the structure and surface acidity of nano AlF3 prepared by the ethylene glycol-mediated sol-gel process, followed by different post treatments including post-fluorination and calcination, were systematically investigated. FT-IR, elemental analysis, XPS and TG-DTA-MS results indicate the ethylene glycol strongly interacts with the as-prepared AlF3 precursor, thus stabilizing the formed nano particles. MAS NMR spectroscopy combined with in situ FT-IR and HRTEM techniques reveal that AlF6, AlO6-xFx and AlO6 species are present in the resulting X-ray amorphous nano AlF3. The fraction of AlF6 species formed after post-fluorination significantly increases, whereas more AlO6-xFx species are formed just after calcination. After a comparable post-fluorination treatment, the CHClF2 dismutation activity at room temperature indicates that nano AlF3 prepared according the ethylene glycol-mediated route does not possess the same super-strong acidity as HS-AlF3 prepared by the fluorolytic sol-gel method, although NH3-TPD and N2-sorption results indicate larger BET surface areas and high concentration of acid sites for the former as compared to the latter. This might be rationalized based on the absence of terminal fluorine species and the presence of a significant number of AlO6-xFx and AlO6 species in the resulting nano AlF3 as revealed by 27Al, 19F MAS NMR and HRTEM. An interesting consequence is that these oxygen-containing species stabilize the microstructure of AlF3 formed, resulting in improved thermal stability of these phases as compared to "classically" prepared HS-AlF3.

Variation of iodine concentration in breast milk and urine in exclusively breastfeeding women and their infants during the first 24 wk after childbirth.

OBJECTIVE: The aim of this study was to observe the variation of iodine concentration in breast milk and urine in exclusively breastfeeding women and their infants during the first 24 wk after childbirth. METHODS: In all, 634 exclusively breastfeeding mother-infant pairs were enrolled at hospital and followed at the 1, 4, 8, 12, 16, and 24 wk postpartum. Spot infant urinary iodine concentration (I-UIC), maternal urinary iodine concentration UIC (M-UIC), and breast milk iodine concentration (BMIC) in bilateral breasts were measured. RESULTS: During the first 24 wk, the median I-UIC was 216 (139-362) and 122 (68-217) µg/L in lactating mothers, both indicating iodine sufficiency. A strong correlation and no difference were found between BMIC in bilateral breasts. The mean BMIC (M-BMIC) of the two breasts was 165 (112-257) µg/L with a Bland-Altman index of 2.1%. Positive correlations were found between M-BMIC and I-UIC (r = 0.353, P < 0.001), between M-BMIC and M-UIC (r = 0.339, P < 0.001), and between I-UIC and M-UIC (r = 0.222, P < 0.001). M-BMIC was significantly higher than M-UIC (P < 0.001) and lower than I-UIC (P < 0.001). M-BMIC declined from week 1 to week 8 postpartum, both I-UIC and M-UIC dropped from week 1 to week 4 postpartum and stabilized thereafter. CONCLUSION: The iodine nutrition in lactating women and infants were adequate during the first 24 wk after childbirth. M-BMIC declined from week 1 to week 8 postpartum. Both I-UIC and M-UIC dropped from week 1 to week 4 postpartum. Further studies are needed to explore a more definitive BMIC and UIC range for an optimal iodine status in lactating women and breastfed infants.

[Investigation and analysis of salt sales and public consumption in supermarkets in Tianjin after salt reform].

OBJECTIVE: To investigate the consumption status of iodized and iodine-free salt and the attitude and reasons for Tianjin residents to choose salt after the reformation of the salt industry systems, and to provide a scientific basis for iodine supplementation and protect the public iodine adequate. METHODS: Stratified sampling method was used to investigate supermarkets of different sizes in 16 districts of Tianjin from December 2017 to May 2018. And 4-8 different sizes supermarkets were selected in the east, south, west, north, and middle directions of each district, and 25 consumers were selected in each district to conduct a questionnaire survey by Population Proportionate Sampling(PPS). Questionnaire survey was used by investigators to ask and record the respondents age, gender, salt type, time to eat a bag of salt, number of people dining, frequency of seafood consumption, special populations in the family(children, pregnant women or lactating women), reasons for choosing iodized salt or iodine-free salt. And the supermarket sales staff were questioned on the type and proportion of salt sold, the monthly sales of iodized salt and non-iodized salt, and the trend of sales volume. RESULTS: The sales volume of iodized salt was significantly greater than that of noniodized salt in the 94 different supermarkets(P<0. 05). Supermarkets with a rise in sales volume of non-iodized salt and iodized salt accounted for 40. 0% and 32. 9%, respectively. Significance difference was found in the prevalence of thyroid disease among people with different salt selection types(χ~2= 15. 052, P<0. 05). The prevalence of thyroid disease is higher in the non-iodized salt group. No significant difference was found in the prevalence of thyroid disease between different genders and age groups(χ~2= 0. 937, P > 0. 05; χ~2=2. 442, P > 0. 05). From the reasons why consumers choose different types of salt, the choice of iodized salt in the population, habits(45. 0%) accounted for a larger proportion, the prevention of thyroid disease accounted for 49. 6%. Among the people who chose to have no iodized salt, it is considered that Tianjin is a seaside city that does not need iodine supplementation, accounting for 55. 9%, and those who prevent thyroid disease account for 35. 6%. Prevention of thyroid disease account for 46. 9% and those who do not need iodine supplementation account for 40. 0% in a mixed population. CONCLUSION: There are blindness and misunderstanding when consumers select the type of salt.