[Clinical and genetics characteristics of adult-onset cerebrotendinous xanthomatosis: analysis of a Chinese pedigree].

Objective: Clinical manifestations, imaging findings, pathologic features, and genetic mutations of Chinese adult patients with cerebrotendinous xanthomatosis (CTX) were analyzed in order to achieve a greater understanding of CTX that can improve early detection, diagnosis, and treatment. Methods: Clinical data including medical history, neurologic and auxiliary examinations, imaging findings, and genetic profile were collected for an adult patient with CTX admitted to the Sixth Medical Center of Chinese People's Liberation Army General Hospital in August 2020. Additionally, a systematic review of genetically diagnosed Chinese adult CTX cases reported in major databases in China and other countries was performed and age of onset, first symptoms, common signs and symptoms, pathologic findings, imaging changes, and gene mutations were analyzed. Results: The proband was a 39-year-old female with extensive, early-onset nervous system manifestations including cognitive dysfunction and ataxia. Systemic lesions included juvenile cataract and a tendon mass. Cranial magnetic resonance imaging revealed cerebral atrophy, symmetric white matter changes predominantly in the pyramidal tract, and lesions in the cerebellar dentate nucleus. A novel homozygous mutation in the sterol-27-hydroxylase (CYP27A1) gene (c.1477-2A>C) was identified. There were no family members with similar clinical presentation although some were carriers of the c.1477-2A>C mutation. The patient showed a good response to deoxycholic acid treatment. Totally there were 56 cases of adult CTX patients in China, mostly in East China (31/56, 55.4%), at a male-to-female ratio of 1.8 to 1. Multiple organs and tissues including nervous system, tendon, lens, lung, and skeletal muscle were affected in these cases. The most common neurologic manifestations were cognitive dysfunction (44/52, 84.6%) and ataxia (44/51, 86.3%). The cases were characterized by early onset, chronic progressive damage of multiple systems, long disease course, and delayed diagnosis, making the disease difficult to manage clinically and resulting in poor prognosis. The 2 most common genetic mutations in Chinese adult CTX patients were c.1263+1G>A and c.379C>T. Exon 2 of the CYP27A1 gene was identified as a mutation hot spot. Conclusions: Chinese adult patients with CTX have complex clinical characteristics, a long diagnostic cycle, and various CYP27A1 gene mutations. Early diagnosis and intervention can improve the prognosis of these patients.

[Morvan syndrome with positive anti LGI1/CASPR2 antibodies in serum/cerebrospinal fluid:a case report and literature review].

To report a typical case of Morvan syndrome with positive anti-leucine rich glioma-inactivated 1(LGI1) and contactin-associated protein 2 (CASPR2) antibodies in serum and cerebrospinal fluid. A 39-years-old female initially presented weakness of extremeties. The main symptoms included paroxysmal limb pain, wheezing, itching, muscle twitching, epilepsy, hypomnesia, dysphoria, apathy, intractable insomnia, salivation and sweating. Tests of electrolytes found hypokalemia (2.7-3.1 mmol/L) and hyponatremia (130-136 mmol/L). Arterial blood gas analysis showed hypoxemia (oxygen saturation 50%-70%). Total thyroxine (TT4) was elevated to 207 nmol/L with positive thyroid peroxidase antibody (TPO-Ab) and thyroglobulin antibody (TG-Ab). LGI1and CASPR2 antibodies (CBA method) were positive in both serum and cerebrospinal fluid, and the remaining antibodies related to autoimmune encephalitis and paraneoplastic syndrome were negative. Head MRI was almost normal, while mild abnormalities were found in electroencephalogram. Electromyography showed slightly increased voltage of left quadriceps motor unit potential. After treated with corticosteroids, IVIG and mycophenolate mofetil, the patient completely improved. Cognitive function scores recovered from MoCA/MMSE (16/24) to MoCA/MMSE (26/29). Positivity of LGI1/CASPR2 antibodies both in serum/cerebrospinal fluid are rarely seen in patients with Morvan syndrome. Steroids and immunosuppressants are suggested for treatment as early as possible.

[Adherence to adjuvant with therapy imatinib in patients with gastrointestinal stromal tumor: a national multi-center cross-sectional study].

Objective: To analyze the current adherence to imatinib in patients with gastrointestinal stromal tumors (GIST) in China and its influencing factors. Methods: A cross-sectional survey was conducted. Study period: from October 1, 2020 to November 31, 2020. Study subjects: GIST patients taking imatinib who were diagnosed and treated in public tertiary level A general hospitals or oncology hospitals; those who had not been pathologically diagnosed, those who never received imatinib, or those who had taken imatinib in the past but stopped afterwards were excluded. The Questionnaire Star online surgery platform was used to design a questionnaire about the adherence to adjuvant imatinib therapy of Chinese GIST patients. The link of questionnaire was sent through WeChat. The questionnaire contained basic information of patients, medication status and Morisky Medication Adherence Scale. Results: A total of 2162 questionnaires from 31 provinces, autonomous regions, and municipalities were collected, of which 2005 were valid questionnaires, with an effective rate of 92.7%. The survey subjects included 1104 males and 901 females, with a median age of 56 (22-91) years old. Working status: 609 cases (30.4%) in the work unit, 729 cases (36.4%) of retirement, 667 cases of flexible employment or unemployment (33.3%). Education level: 477 cases (23.8%) with bachelor degree or above, 658 cases (32.8%) of high school, 782 cases (39.0%) of elementary or junior high school, 88 cases (4.4%) without education. Marital status: 1789 cases (89.2%) were married, 179 cases (8.9%) divorced or widowed, 37 cases (1.8%) unmarried. Two hundred and ninety-four patients (14.7%) had metastasis when they were first diagnosed, including 203 liver metastases, 52 peritoneal metastases, and 39 other metastases. One thousand eight hundred and sixty-nine patients underwent surgical treatment, of whom 1642 (81.9%) achieved complete resection. The median time of taking imatinib was 25 (1-200) months. Common adverse reactions of imatinib included 1701 cases (84.8%) of periorbital edema, 1031 cases (51.4%) of leukopenia, 948 cases (47.3%) of fatigue, 781 cases (39.0%) of nausea and vomiting, 709 cases (35.4%) of rash, and 670 cases (33.4%) of lower extremity edema. The score of the Morisky Medication Adherence Scale showed that 392 cases (19.6%) had poor adherence, 1023 cases (51.0%) had moderate adherence, and 590 cases (29.4%) had good adherence. Univariate analysis showed that gender, age, work status, economic income, residence, education level, marriage, the duration of taking medication and adverse reactions were associated with adherence to adjuvant imatinib therapy (all P<0.05). Multivariate analysis showed that female (OR=1.264, P=0.009), non-retirement (OR=1.454, P=0.001), monthly income ≤4000 yuan (OR=1.280, P=0.036), township residents (OR=1.332, P=0.005), unmarried or divorced or widowed (OR=1.362, P=0.026), the duration of imatinib medication >36 months (OR=1.478, P<0.001) and adverse reactions (OR=1.719, P=0.048) were independent risk factors for poor adherence to adjuvant imatinib. Among patients undergoing complete resection, 324 (19.7%) had poor adherence, 836 (50.9%) had moderate adherence, and 482 (29.4%) had good adherence. Meanwhile, 55 patients with good adherence (11.4%) developed recurrence after surgery, 121 patients with moderate adherence (14.5%) developed recurrence, 61 patients with poor adherence (18.8%) developed recurrence, and the difference was statistically significant (P=0.017). Conclusions: The adherence to adjuvant therapy with imatinib in Chinese GIST patients is relatively poor. Females, non-retirement, monthly income ≤4000 yuan, township residents, unmarried or divorced or widowed, the duration of imatinib medication >36 months, and adverse reactions are independently associated with poor adherence of GIST patients. Those with poor adherence have a higher risk of recurrence after surgery. Positive interventions based on the above risk factors are advocated to improve the prognosis of patients with GIST.

[Tough choice of surgical treatment for duodenal gastrointestinal stromal tumor: pancreaticoduodenectomy or local resection?]

The therapeutic choice of duodenal gastrointestinal stromal tumor (GIST) has always been the focus of surgeons because of its special anatomy location. So far, surgery is the preferable treatment for primary duodenal GIST, including pancreaticoduodenectomy (PD) and local resection (LR). Researches reveal that the prognosis of duodenal GIST is determined by the pathologic factors of the tumor itself, and is not significantly associated with the surgical procedure. The intervention with targeted drugs such as imatinib has given the duodenal GIST more opportunities for LR. Meanwhile, the technique development of the laparoscopy combined with endoscopic surgery and robotic surgery ensures the steps of minimally invasive treatment for duodenal GIST into a new era.

[Clinical presentations of neuromyelitis optica spectrum disorders with ultra-longitudinally extensive transverse myelitis].

Objective: To analyze the clinical presentations of neuromyelitis optica spectrum disorders (NMOSD) with ultra-longitudinally extensive transverse myelitis (uLETM), in order to improve the diagnostic accuracy of this disorder. Methods: Twenty-two uLETM patients was recruited and retrospectively analyzed for general clinical characteristics, laboratory tests and MRI characteristics, as well as therapeutic. Results: (1)The Male-to-female ratio was 1∶6. The median onset age was 31 years old. The duration from the first relapse to the onset was 5.5 months. (2)The positive rate of serum water channel aquaporin-4 antibody (AQP4-Ab) in the acute phase was 86.4%. The positive rate of cerebrospinal fluid (CSF) AQP4-Ab in the acute phase was 69.2%. The positive rate of autoimmune antibodies was 72.7%. There was a remarkable difference (Z=-12.632, P=0.000) in serum AQP4-Ab titer levels between with the acute and remission period (median titer of 1∶244.78 to 1∶139.63). There was a remarkable difference (Z=-20.161, P=0.000) in geometric mean of serum AQP4-Ab titer levels between with CSF AQP4-Ab positive (1∶289.8) and negative (1∶36.2). (3)63.6% of the uLETM patients had 10-15 contiguous segments, 31.8% had 16-19 contiguous segments and 4.5% had whole spinal cord affected. 72.7% of the lesions of uLETM were sliver. The detection rate of optic nerve lesion by MRI was 63.6% and brain sliver lesions was seen in 63.6% of the patients.(4) All patients improved after treatment with high-dose glucocorticoids (GCs) in the acute phase. 15 cases treated with long-term oral administration of low-dose GCs in remission stage of NMOSD. 6 cases treated with mycophenolate mofetil. 1 case treated with intravenous immunoglobulins. Conclusions: NMOSD with uLETM is predominantly seen in young woman. The high risk period of relapse is 5.5 months after the onset. A high portion of NMOSD patients with uLETM have serum and CSF AQP4-Ab in acute phase. The therapy of GCs is recommended in acute phase. Combination of GCs with immunosuppressant can achieve stable and satisfactory effect in remission period of NMOSD.

[A clinical analysis of 5 patients with infratentorial primary angiitis of central nervous system].

Objective: To explore the clinical characteristics of infratentorial primary angiitis in central nervous system(PACNS). Methods: A total of 5 cases diagnosed as infratentorial PACNS in the neurology department of Navy General Hospital of PLA in 2015 were enrolled in the study. The clinical, imaging and pathological data were collected and analyzed. Results: All the 5 cases were male with the median onset age of thirty-four. Five cases presented with dizziness, two with headache, three with walking unstable, two with facial numbness and one with dysarthria. Rising pressure of cerebrospinal fluid (CSF) (190-245 cmH(2)O, 1 cmH(2)O=0.098 kPa) was found in 4 cases by the lumbar puncture, mildly increased number of leukocyte in 2 cases [(12-28)×10(6)/L], increased CSF protein in 3 cases(540-979 mg/L) and increased IgG index in 3 cases(0.84-1.45). Pons lesions were revealed by magnetic resonance imaging(MRI)in 4 cases, brachium pontis lesions in 2 cases, cerebellum lesions in 2 cases, one with midbrain lesion in 1 case, unilateral lesions in 4 cases and bilateral lesion in 1 case. Different degree of edema and mass effect were shown in all lesions by MRI. Patch like enhancement was found by contrast MRI in 5 cases and meningeal enhancement in 2 cases. Elevation of choline(Cho)peak was found by magnetic resonance spectroscopy(MRS)in 4 cases, reduction of N-acetyl aspartate(NAA) peak in 3 cases, appearance of lactate peak in 1 case and lipid peak in another case. Arterial spin labeling(ASL) was performed in 4 cases and no hyperperfusion was found. Susceptibility weighted imaging(SWI) was performed in 3 cases and microhemorrhage in the lesions was found in 2 cases and normal in 1 case. Magnetic resonance arteriography(MRA) was performed in 1 case and no stenosis was found. Digital subtraction arteriography(DSA) was performed in 1 case and multiple stenosis of the intracranial arteries was showed. Two cases had taken the stereotactic brain biopsy and the histopathologic diagnosis was angiitis. Five cases were treated with methylprednisolone and cyclophosphamide was added on in 1 case. Good prognosis was found in all cases. Conclusions: Infratentorial PACNS mostly attacks middle-aged males. The lesions tend to locate in unilateral pons, brachium pontis, cerebellum and midbrain. Hemorrhage or microhemorrhage in lesions is often found by SWI and no hyperperfusion is shown by ASL, which would be useful to distinguish PACNS from malignant tumors. Given the limitations of brain biopsy in clinical practice, clinical and imaging features would be helpful to diagnose PACNS.

[Characteristics of sympathetic skin response in patients with multiple system atrophy].

Objective: To provide evidence for early clinical diagnosis of multiple system atrophy(MSA)by studying the characteristics of sympathetic skin responses(SSR) in the patients with MSA. Methods: A total of 47 MSA patients and 32 healthy individuals were enrolled as case group and normal control(NC) group, from in and out patients of Neurology Department of Navy General Hospital from July 2013 to August 2015. SSR was tested by Nicolet electromyography, the latency and abnormal and disappeared rate of SSR were compared. Results: The SSR latency of upper limbs and lower limbs in MSA group had statistical significance compared respectively with the NCgroup (upper limbs: SSR latency was(1 485±187)ms in MSA group, and(1 375±108)ms in NC group, P<0.05; lower limbs: SSR latency was(2 200±386)ms in MSA group, and(1 994±240)ms in NC group, P<0.05). Sex and age had no significant effect on the latency and the abnormal and disappeared rate of SSR in two groups (P>0.05). The upper and lower limb SSR latency in MSA patients with disease duration more than 2 years(SSR latency was (1 592±160)ms in upper limb and (2 268±254)ms in lower limb) were longer than those within 2 years(SSR latency was (1 453±184)ms in upper limb and (2 190±442)ms in lower limb), but only the upper limbs had significantly statistical differences (P<0.05). Both SSR abnormal rate and SSR disappeared rate in MSA patients whose disease duration were more than 2 years(SSR abnormal rate: 85.00%, SSR disappeared rate: 75.00%) were higher than those with shorter disease duration(SSR abnormal rate: 55.56%, SSR disappeared rate: 22.22%), and both were statistically significant (SSR abnormal rate: P<0.05, SSR disappeared rate: P<0.001). The upper and lower limb SSR latency of MSA-C subgroup had no statistical difference compared with MSA-P subgroup(P>0.05). The SSR abnormal rate in MSA-C subgroup(78.13%) was higher than that of MSA-P subgroup(46.76%), and were statistically significant (P<0.05). The SSR disappeared rate in MSA-C subgroup has no statistical difference compared with the MSA-P subgroup(P>0.05). Conclusions: SSR is helpful to diagnose MSA. The latency and the abnormal and disappeared rate of SSR are significantly increased with the extension of MSA duration. The SSR abnormal rate in MSA-C patients is higher than that in MSA-P patients, and symmetrically abnormal SSR is more supporting the diagnosis of MSA.

[The correlation factor analysis for conversion of clinically isolated syndrome to multiple sclerosis and neuromyelitis optica].

OBJECTIVE: To analyze the features of patients who converted from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and neuromyelitis optica (NMO) and explore the correlated factors. METHODS: A total of 151 patients admitted in our unit as CIS from January 2009 to December 2014 were enrolled in the study. All patients were divided into the following four groups by locations of the initial lesion, which were the spinal cord, the optic nerve, the brain stem and the multifocal lesions. Data were collected at the baseline including demographics, expanded disability status scale (EDSS) score, site of CIS, presence or absence of cerebrospinal fluid (CSF) oligoclonal bands (OB) and serum aquaporin-4 antibody (AQP4-Ab), evoked potential (EP) and MRI lesions. The conversion rates from CIS to clinically definite MS or NMO were calculated and the correlated factors were explored. RESULTS: With a mean follow-up period of (44.11±17.62)months, 46/151(30.5%) patients converted to MS, 28/151 (18.5%) to definite NMO and 66/151 patients(43.7%)remained as CIS. Other patients were converted to optic neuritis(4/151), one-time transverse myelitis(3/151), acute disseminated encephalomyelitis (1/151) and Balo concentric sclerosis(3/151) . The EDSS score was significantly higher in patients converted to NMO than those converted to MS (P=0.003). The initial manifestation of optic neuritis significantly correlated with the conversion to NMO (P=0.000), while the initial manifestation of CIS with multifocal lesions significantly correlated with the conversion to MS (P=0.000). Neither the isolated BAEP (P=0.703), VEP (P=0.076), SEP (P=0.915) nor the combination of two (P=0.546)or three (P=1.000) of the above parameters could help to distinguish the conversion to MS or NMO. More patients with positive CSF-OB converted to MS (P=0.001), while more patients with positive serum AQP4-Ab converted to NMO (P=0.001). More patients were serum AQP4-Ab positive in those converted to NMO than those converted to MS (P=0.000). Lesions longer than three vertebral segments were dominant in patients converted to NMO (P=0.000). The logistic regression analysis revealed that factors correlated with conversion from CIS to MS were the initial CIS manifestation of multifocal lesions (OR=4.775, P=0.002), positive CSF-OB (OR=7.794, P=0.002) and VEP abnormality (OR=7.251, P=0.001). Factors correlated with conversion from CIS to NMO were female in gender (OR=12.536, P=0.019), positive serum AQP4-Ab (OR=36.410, P=0.002), lesions longer than three vertebral segments (OR=93.602, P=0.001), abnormal VEP and SEP (OR=18.448, P=0.002; OR=12.731, P=0.016). CONCLUSIONS: Factors correlated with the conversion from CIS to MS are initial CIS manifestation of multifocal lesions, positive CSF-OB and abnormal VEP, while those correlated with the conversion from CIS to NMO are female in gender, positive serum AQP4-Ab, initial CIS manifestation with optic nerve, lesions involved more than three vertebral segments and abnormal VEP and SEP.

Ischemia preconditioning is neuroprotective in a rat cerebral ischemic injury model through autophagy activation and apoptosis inhibition.

Sublethal ischemic preconditioning (IPC) is a powerful inducer of ischemic brain tolerance. However, its underlying mechanisms are still not well understood. In this study, we chose four different IPC paradigms, namely 5 min (5 min duration), 5×5 min (5 min duration, 2 episodes, 15-min interval), 5×5×5 min (5 min duration, 3 episodes, 15-min intervals), and 15 min (15 min duration), and demonstrated that three episodes of 5 min IPC activated autophagy to the greatest extent 24 h after IPC, as evidenced by Beclin expression and LC3-I/II conversion. Autophagic activation was mediated by the tuberous sclerosis type 1 (TSC1)-mTor signal pathway as IPC increased TSC1 but decreased mTor phosphorylation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and hematoxylin and eosin staining confirmed that IPC protected against cerebral ischemic/reperfusion (I/R) injury. Critically, 3-methyladenine, an inhibitor of autophagy, abolished the neuroprotection of IPC and, by contrast, rapamycin, an autophagy inducer, potentiated it. Cleaved caspase-3 expression, neurological scores, and infarct volume in different groups further confirmed the protection of IPC against I/R injury. Taken together, our data indicate that autophagy activation might underlie the protection of IPC against ischemic injury by inhibiting apoptosis.

Ischemia preconditioning is neuroprotective in a rat cerebral ischemic injury model through autophagy activation and apoptosis inhibition

Sublethal ischemic preconditioning (IPC) is a powerful inducer of ischemic brain tolerance. However, its underlying mechanisms are still not well understood. In this study, we chose four different IPC paradigms, namely 5 min (5 min duration), 5×5 min (5 min duration, 2 episodes, 15-min interval), 5×5×5 min (5 min duration, 3 episodes, 15-min intervals), and 15 min (15 min duration), and demonstrated that three episodes of 5 min IPC activated autophagy to the greatest extent 24 h after IPC, as evidenced by Beclin expression and LC3-I/II conversion. Autophagic activation was mediated by the tuberous sclerosis type 1 (TSC1)-mTor signal pathway as IPC increased TSC1 but decreased mTor phosphorylation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and hematoxylin and eosin staining confirmed that IPC protected against cerebral ischemic/reperfusion (I/R) injury. Critically, 3-methyladenine, an inhibitor of autophagy, abolished the neuroprotection of IPC and, by contrast, rapamycin, an autophagy inducer, potentiated it. Cleaved caspase-3 expression, neurological scores, and infarct volume in different groups further confirmed the protection of IPC against I/R injury. Taken together, our data indicate that autophagy activation might underlie the protection of IPC against ischemic injury by inhibiting apoptosis.

Multi-step magnetization of the Ising model on a Shastry-Sutherland lattice: a Monte Carlo simulation.

The magnetization behaviors and spin configurations of the classical Ising model on a Shastry-Sutherland lattice are investigated using Monte Carlo simulations, in order to understand the fascinating magnetization plateaus observed in TmB(4) and other rare-earth tetraborides. The simulations reproduce the 1/2 magnetization plateau by taking into account the dipole-dipole interaction. In addition, a narrow 2/3 magnetization step at low temperature is predicted in our simulation. The multi-step magnetization can be understood as the consequence of the competitions among the spin-exchange interaction, the dipole-dipole interaction, and the static magnetic energy.

Optimized blood cell profiling method for genomic biomarker discovery using high-density microarray.

High-quality biomarkers for disease progression, drug efficacy and toxicity liability are essential for improving the efficiency of drug discovery and development. The identification of drug-activity biomarkers is often limited by access to and the quantity of target tissue. Peripheral blood has increasingly become an attractive alternative to tissue samples from organs as source for biomarker discovery, especially during early clinical studies. However, given the heterogeneous blood cell population, possible artifacts from ex vivo activations, and technical difficulties associated with overall performance of the assay, it is challenging to profile peripheral blood cells directly for biomarker discovery. In the present study, Applied BioSystems' blood collection system was evaluated for its ability to isolate RNA suitable for use on the Affymetrix microarray platform. Blood was collected in a TEMPUS tube and RNA extracted using an ABI-6100 semi-automated workstation. Using human and rat whole blood samples, it was demonstrated that the RNA isolated using this approach was stable, of high quality and was suitable for Affymetrix microarray applications. The microarray data were statistically analysed and compared with other blood protocols. Minimal haemoglobin interference with RNA labelling efficiency and chip hybridization was found using the TEMPUS tube and extraction method. The RNA quality, stability and ease of handling requirement make the TEMPUS tube protocol an attractive approach for expression profiling of whole blood to support target and biomarker discovery.

Genetic differentiation of wild relatives of rice as assessed by RFLP analysis.

To study genetic diversity and relationships of wild relatives of rice, 58 accessions of Oryza rufipogon, Oryza nivara, Oryza sativa f. spontanea and the cultivated Oryza sativa, representing a wide range of their distribution, were analyzed using the restriction fragment length polymorphism (RFLP) technique. All 30-used RFLP probes detected polymorphisms among the Oryza accessions, with an average of 3.8 polymorphic fragments per probe. Considerable genetic diversity was scored among the Oryza accessions with a similarity coefficient ranging from 0.28 to 0.93; but the cluster analysis of the accessions did not show an apparent grouping based on the species classification, instead they were scattered randomly in different groups. Noticeably, the Oryza accessions from the same geographic region, or near-by geographic regions, tended to be clustered in the same groups. The indica rice varieties showed relatively high genetic diversity and were scattered in different groups of their wild relatives, but the japonica varieties showed a relatively low variation and formed an independent group. It is concluded from the molecular analytical result that: (1) the four Oryza taxa have a remarkably close relationship and their independent species status need to be carefully reviewed; (2) geographic isolation has played a significant role in the differentiation of the Oryza accessions; therefore, a wide geographic range needs to be covered in collecting wild rice germplasm for ex situ conservation; and (3) the conventional conclusion of indica rice being directly domesticated from its ancestral wild species, and japonica rice being derived from indica, gains support from our data.

Identifying different types of de-differentiated microspores from indica-japonica F(1) hybrids with subspecies-differentiating RFLP probes in rice.

The indica, japonica and intermediary types of de-differentiated microspores from indica-japonica F(1) hybrids were identified with 11 subspecies-differentiating RELP probes in rice (Oryza sativa L.). The results showed that the distribution of indica, japonica and intermediary types of de-differentiated microspores could be easily detected in a simple and quick way using the RFLP method. Moreover, the microspores from the same F(1) hybrid but inoculated onto different media, or microspores from different F(1) hybrids when inoculated onto the same medium, often displayed distinctive distribution curves of de-differentiated microspores types, indicating that the media employed in this experiment had high selectivity for the de-differentiation of certain types of microspores. The application of the RELP method to de-differentiated microspore identification is of great theoretical and practical significance in rice doubled-haploid breeding.

RFLP mapping of QTLs for yield and related characters in rice (Oryza sativa L.).

Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F2 populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143-RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7-11.5 g. QTL mapping in two populations with a common male parent is compared and discussed.

Identification of a set of RFLP probes for subspecies differentiation in Oryza sativa L.

Sixty-eight indica-japonica tester-differentiating RFLP probes were tested in seven indica and seven japonica varieties of rice (Oryza sativa L.) with four enzyme digestions (EcoRI, EcoRV, HindIII and DraI). Twenty-one DNA clones were isolated as indica-japonica subspecies-differentiating probes. A set of 13 probes was established as core probes for subspecies differentiation and a pooled blotting analysis was carried out to facilitate the application of RFLP in rice genetics and breeding practice. A dendrogram of 12 wide-compatibility varieties was constructed based on RFLPs detected by 13 core probes with single enzyme digestions. It was speculated that most RFLPs of indica-japonica differentiating probes were generated by insertions/deletions, which may be of great significance for the origin and differentiation of subspecies in Oryza sativa L.