The different outcomes in the elderly with subclinical hypothyroidism diagnosed by age-specific and non-age-specific TSH reference intervals: a prospectively observational study protocol.

Introduction: Subclinical hypothyroidism (SCH) is a common endocrine disorder characterized by elevated thyroid-stimulating hormone (TSH) levels and normal free thyroxine (FT4) levels. The overdiagnosis and overtreatment of SCH in elderly patients have become concerns as TSH levels naturally increase with age. Studies have shown that many elderly patients with SCH can recover without treatment, and the administration of levothyroxine (L-T4) does not improve their prognosis. Therefore, It is necessary to establish age-specific reference ranges for TSH in elderly individuals to aid in clinical decision-making and prevent overdiagnosis. Methods: This is a multicenter prospective study that focuses on Chinese elderly patients with SCH who have TSH levels below 10 mU/L. After obtaining the informed consent of the patients, their initial diagnosis information will be registered, and they will be asked to fill out questionnaires such as the Montreal Cognitive Assessment-Basic (MoCA-B), Hamilton Depression Scale (HAMD), Hypothyroidism Symptom Questionnaire (SRQ), frail scale(FRAIL), fatigue scale, and EQ-5D. In addition, thyroid function tests, blood lipid analysis, carotid artery ultrasound, and thyroid ultrasound examinations will be conducted. Patients will also be grouped according to FT4 levels, the changes in FT4 and its relationship with TSH can also be described. For patients over 80 years old, a decrease in FT4 will be used as an endpoint event, while for patients between 60-80 years old, TSH levels greater than or equal to 10mIU/L or a decline in FT4 will be used as the endpoint event. The TSH reference intervals of the general and elderly populations will be used to calculate medical costs associated with multiple follow-ups of patients, and a social-economic analysis will also be conducted. Discussion: This study will prospectively observe elderly patients with SCH who are screened using both age-specific and non-age-specific TSH reference ranges for the elderly population. We will compare the results of elderly patients diagnosed with SCH using different reference ranges and analyze their association with FT4 to identify meaningful SCH patients and reduce over diagnosis and over treatment of elderly SCH. Ethics: The Medical Science Research Ethics Committee of the First Affiliated Hospital of China Medical University approved this study (ID: AF-SOP-07-1.1-01). The results will be published in an open-access journal. Clinical trial registration: https://www.chictr.org.cn/, identifier ChiCTR2300070831.

Genome assembly of Nannochloropsis oceanica provides evidence of host nucleus overthrow by the symbiont nucleus during speciation.

The species of the genus Nannochloropsis are unique in their maintenance of a nucleus-plastid continuum throughout their cell cycle, non-motility and asexual reproduction. These characteristics should have been endorsed in their gene assemblages (genomes). Here we show that N. oceanica has a genome of 29.3 Mb consisting of 32 pseudochromosomes and containing 7,330 protein-coding genes; and the host nucleus may have been overthrown by an ancient red alga symbiont nucleus during speciation through secondary endosymbiosis. In addition, N. oceanica has lost its flagella and abilities to undergo meiosis and sexual reproduction, and adopted a genome reduction strategy during speciation. We propose that N. oceanica emerged through the active fusion of a host protist and a photosynthesizing ancient red alga and the symbiont nucleus became dominant over the host nucleus while the chloroplast was wrapped by two layers of endoplasmic reticulum. Our findings evidenced an alternative speciation pathway of eukaryotes.

Genetic analysis and mapping of a thermosensitive genic male sterility gene, tms6(t), in rice (Oryza sativa L.).

Thermosensitive genic male-sterile (TGMS) rice is widely used in hybrid rice production. Because of its specific temperature requirement, it can be used only in a narrow rice-growing zone in Asia. A newly discovered TGMS line, G20S, has an opposite phenotype compared with normal TGMS lines. G20S is completely sterile when the temperature is lower than 29.5 degrees C. Thus, it can be widely used in a larger area. Genetic analysis indicated that the sterility of G20S was controlled by a single recessive gene that was named tms6(t). An F2 population from the cross between G20S and Jing226 was developed and used for molecular mapping of the tms6(t) gene. The simple sequence repeat technique, combined with bulked segregant analysis, was used to screen markers linked to the target gene, and linkage markers such as RM216, RM2504, RM3152, and RM4455 were identified. These markers are all located on chromosome 10; therefore, tms6(t) was subsequently mapped on chromosome 10. Co-segregation analysis using the F2 population showed that two of these markers, RM3152 and RM4455, were closely linked to tms6(t) at distances of 3.00 cM and 1.10 cM, respectively. Additionally, integration of the genetic and physical maps showed that there were 15 BAC/PAC clones overlapping between RM3152 and RM4455, and tms6(t) was mapped to an interval of 1455 kb.

Genetic analysis and molecular mapping of a nuclear recessive male sterility gene, ms91(t), in rice.

Mutations that result in plant male sterility provide means not only to probe reproductive development but also to facilitate commercial heterosis application and hybrid seed production. In this study, we report a novel male sterility gene, ms91(t), in a spontaneous mutant line (SH38) from a Chinese rice cultivar (Oryza sativa subsp. japonica 'Jijing14'). The sterility of SH38 was studied by examining its progenies derived from crosses with 6 japonica cultivars. Corresponding F2 populations were obtained by selfing each of the 6 F1s and a backcross population was produced by crossing SH38 to the F1 of SH38 x C18. Our results revealed that SH38 has normal agronomic traits but produces no pollen grains. Segregations of male-sterile and male-fertile progenies in the F2 and backcross populations fit well with ratios of 3:1 and 1:1, respectively, indicating that ms91(t) is a single recessive gene. Amplified fragment length polymorphism (AFLP) analysis of SH38 and Jijing14 plants showed the presence of a unique band in SH38. Simple sequence repeat (SSR) analysis of the bulked and individual progenies of the F2 population of SH38 x C18 showed linkage of ms91(t) with the SSR marker RM5853 on chromosome 1. Subsequently, ms91(t) was fine-mapped to the interval between markers RM7075 (3.75 cM) and RM5638 (3.57 cM). Our results would facilitate the isolation of ms91(t) and male sterility in heterosis application.