Full-length transcriptome analysis of maize root tips reveals the molecular mechanism of cold stress during the seedling stage.

BACKGROUND: As maize originated in tropical or subtropical zones, most maize germplasm is extremely sensitive to low temperatures during the seedling stage. Clarifying the molecular mechanism of cold acclimation would facilitate the breeding of cold tolerant maize varieties, which is one of the major sustainability factors for crop production. To meet this goal, we investigated two maize inbred lines with contrasting levels of cold tolerance at the seedling stage (IL85, a cold tolerant line; B73, a cold sensitive line), and performed full-length transcriptome sequencing on the root tips of seedlings before and after 24 h of cold treatment. RESULTS: We identified 152,263 transcripts, including 20,993 novel transcripts, and determined per-transcript expression levels. A total of 1,475 transcripts were specifically up-regulated in the cold tolerant line IL85 under cold stress. GO enrichment analysis revealed that 25 transcripts were involved in reactive oxygen species (ROS) metabolic processes and 15 transcripts were related to the response to heat. Eight genes showed specific differential alternative splicing (DAS) in IL85 under cold stress, and were mainly involved in amine metabolism. A total of 1,111 lncRNAs were further identified, 62 of which were up-regulated in IL85 or B73 under cold stress, and their corresponding target genes were enriched in protein phosphorylation. CONCLUSIONS: These results provide new insights into the molecular mechanism of cold acclimation during the seedling stage in maize, and will facilitate the development of cultivars with improved cold stress tolerance.

Association of clinicians' perceived social support and development of anxiety and depression / 中国职业医学

OBJECTIVE: To explore the relationship of clinicians' perceived social support and development of anxiety and depression. METHODS: A total of 434 clinicians from 3 comprehensive grade A hospitals in Guangdong Province were selected as study subjects by cluster random sampling method. The questionnaires of Perceived Social Support Scale,Selfrating Anxiety Scale and Self-rating Depression Scale were used to investigate their perceived social support,anxiety and depression respectively. RESULTS: The total scores of perceived social support,anxiety and depression in clinicians were(60. 6 ± 9. 9),(40. 9 ± 8. 3),and(45. 0 ± 10. 2),respectively. The detection rates of high perceived social support status,anxiety and depression were 56. 7%(246/434),15. 9%(69/434),and 23. 5%(102/434),respectively. The scores of perceived social support of clinicians with anxiety or depression were significantly lower than the scores of those without anxiety or depression( P < 0. 01). There was a negative correlation between anxiety,depression and perceived social support( P < 0. 01). CONCLUSION: The clinicians' perceived social support is closely related to the occurrence of anxiety and depression. Effective perceived social support can alleviate some of the clinicians' anxiety,depression and other adverse psychological reactions,and improve their mental health.

The significance of 8-hydroxy-deoxyguanosine acid in the diagnosis of nonalcoholic steatohepatitis / 中华内科杂志

Objective To evaluate the significance of serum 8-hydroxy-deoxyguanosine acid ( 8-OHdG) in the diagnosis of nonalcoholic steatohepatitis ( NASH).Methods Patients or healthy subjects were enrolled at the Second Hospital of Tianjin Medical University and the Second People ′s Hospital of Tianjin from May 2013 to December 2015.A total of 41 patients with nonalcoholic fatty liver disease were enrolled in the study , including 20 nonalcoholic simple fatty liver ( NAFL) patients and 21 NASH patients whose diagnosis were proven by liver biopsy.The other 32 healthy subjects were studied as controls.Serum 8-OHdG, ALT, AST and GGT were tested.Nonalcoholic fatty liver disease activity score ( NAS ) and expression of 8-OHdG in liver was investigated between NAFL patients and NASH patients.The correlations between serum 8-OHdG and serum ALT , AST, GGT, and 8-OHdG in liver tissue in NASH group were investigated.In addition , the receiver operating characteristic ( ROC) curve analyses for ALT and 8-OHdG levels were performed in NAFL patients and NASH patients , and the cut-off value was determined.Results Serum 8-OHdG values in healthy controls , NAFL and NASH patients were (0.19 ±0.16) μg/L, (0.22 ±0.16) μg/L, (0.42 ±0.21) μg/L respectively.The serum 8-OHdG and serum ALT, GGT and 8-OHdG in liver tissue were all positively correlated in NASH group with respective correlation coefficient r values as 0.454 7, 0.382 9, and 0.497 6.AUC of 8-OHdG was 0.901 with cut-off value 0.39 μg/L.Its sensitivity was 88.3%and specificity was 81.5%, which were higher than those of ALT.Conclusion The value of serum 8-OHdG would be used as a marker for the diagnosis of NASH.

DNA sequence analysis of the triose phosphate isomerase gene from isolates of Giardia lamblia / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To confirm the genetic relation between Giardia lamblia (G. lamblia) isolates from different geographic regions of China and other countries.</p><p><b>METHODS</b>Genomic DNA were extracted from the trophozoites or cysts of Giardia lamblia. The triose phosphate isomerase (tim) gene was amplified using polymerase chain reaction (PCR) technique. PCR products were digested with endonuclease and sequenced. The data of sequencing were analyzed with the DNAstar software and compared with that of the isolates acquired from GenBank.</p><p><b>RESULTS</b>Of nine isolates of Giardia lamblia from China (C1, C2, CH2 and CH3), Cambodia (CAM), Australia (A1 and A2) and America (BP and CDC), respectively, 3 (A1, A2 and CAM) fit into Group 1 (WB), 2 (CH2 and CH3)) into Group 2, and 4 (C1, C2, BP and CDC) into Group 3 (GS). The results confirmed the genetic relatedness of G. lamblia isolates from all over the world.</p><p><b>CONCLUSION</b>Genotyping isolates of G. Lamblia provides important information for establishing the phylogenetic relationship or for the epidemiological evaluation of the spreading of this organism.</p>

Establishment of a C57BL/6N mouse model of giardiasis / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To establish a C57BL/6N mouse model infected with Giardia lamblia (G. lamblia) isolates from human origin.</p><p><b>METHOD</b>Two groups of C57BL/6N mouse were inoculated with purified cysts of two G. lamblia isolates (CD and XZ) by gavage separately. Patterns and curves of cyst excretion of the infected mice were observed and summarized. Histopathological changes of the small intestines of the infected mice were observed.</p><p><b>RESULTS</b>Thirty-six mice receiving 1 x 10(4) cysts each were all infected. The C57BL/6N mouse showed high susceptibility to G. lamblia infection. There was no notable distinction between the two groups of the mice infected by the cysts of CD and XZ isolates. Cyst excretion occurred with intermittence. Of 36 infected mice, 32 (89%) passed cysts intermittently and 4 (11%) others persistently. The latent period of cyst excretion was 0 - 3 days p.i. (post-inoculation). The interruption of cyst excretion ranged from 12 to 20 days p.i. The fastigium of the cyst excretion was on day 6 p.i. The peak count of the cysts passed during a 2 h collection period was 2.3 x 10(7)/g fecal specimen. Edema, inflammation, cell infiltration, small blood vessels congestion, mitotic figures and mucosa necrosis appeared in sections of intestines.</p><p><b>CONCLUSION</b>C57Bl/6N mouse is a suitable animal model of G. lamblia.</p>

The intraspecific difference of the triose phosphate isomerase (tim) gene from Giardia lamblia / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the intraspecific difference of the triose phosphate isomerase (tim) gene from Giardia lamblia (G. lamblia).</p><p><b>METHODS</b>Total genomic DNA of G. lamblia was extracted and partial fragments of the triose phosphate isomerase (tim) gene were amplified by polymerase chain reaction (PCR). All nucleotide sequences were analyzed by using a phylogenetic analysis, which was constructed with parsimony and Neighbor-joining (N-J) methods.</p><p><b>RESULTS</b>A total of 124 variable sites (23% of all sequences detected) was defined, most of which were found at the silent sites of codons. Two similar phylogenetic trees were constructed, subdividing 16 Giardia isolates into two groups.</p><p><b>CONCLUSION</b>The genetic diversity of G. lamblia appeared to be little affected by factors of both host and geography, while natural-selection played an important role in DNA molecular evolution level of the tim gene. The tim gene may be considered a very useful genetic marker of the population genetic structure of G. lamblia.</p>

The Injury of Metronidazole on Morphology of Giardia lamblia in Vitro / 中国寄生虫学与寄生虫病杂志

Trophozoites of Giardia lamblia were axenically cultivated with modified TYI-S-33 medium contained 500 ?g/ml metronidazole(12h LC50).The morphology of drug-treated trophozoites was observed with light and electron micro-scopes at 2,4,8,12 h respectively.The light microscopy revealed that the trophozoites treated with MTZ showed swollen,detached from the wall of the culture tube,and were with vacuoles in the cytoplasm.Movement of the flagella become slowly or stopped.Electronic microscopy showed that the trophozoites were swollen and deformed;lots of vacuoles were seen in the cytoplasm;the contents of cytoplasm were depleted and the nuclei deformed.This study indicated that MTZ has injured the morphology of G.lamblia.

DIAGNOSING GIARDIASIS BY DETECTING GIARDIA LAMBLIA ANTIGEN IN FECAL MATTER WITH COUNTERIMMUNOELECTROPHOKESIS / 中国寄生虫学与寄生虫病杂志

Fecal specimens of 35 parasitologically confirmed cases of giardiasis, 41 acute, gastroenteritis, 23 acute baciUary dysentery, 40 normal persons and 15 jirds experimentally infected with G. lamblia were tested with conterimmunoelectrophoresis (CIE). It was found that 33(94%) out of the 35 giardiasis patients and 14(93%) out of 15 infected jirds showed positive reaction, while fecal specimens of other cases, normal persons, or normal jirds all showed negative reaction. Besides, CIE was performed in 4 giardiasis patients before and after metronidazole treatment. Prior to metronidazole, they were all CIE positive, one day post metronidazole, 3 of them were still CIE positive, and Giardia cysts or trophozoites were also present in their stools. However, from the second day onwards, all of them became CIE negative, while cysts or trophozoites also disappeared from their stools. Apparently, detecting Giardia antigen in fecal specimens with CIE of feces is not only a sensitive tool for detecting current infection, but also a, useful tool for evaluating therapeutic effects in giardiasis.

Continuous Axenic Cultivation of Pneumocystis carinii Isolated from the Bronchoalveolar Lavage Fluid of Infected Rat / 中国寄生虫学与寄生虫病杂志

Objective To establish axenic cultivation of Pneumocystis carinii (P.c). Methods The organisms of P.c were isolated from the bronchoalveolar lavage fluid (BALF) of the rats with Pneumocystis carinii pneumonia (PCP) and cultured in a medium which was based on IMDM (GIBCO) supplemented with S-adenosyl-L-methionine, putrescine, N-acetyl glucosamine, putrescine, L-cysteine and L-glutamine, and newborn calf serum. The organisms cultured in the system were identified by observing the morphology of cysts in smears stained with Gomori's methenamine silver nitrate stain (GMS). Ultrastructure of the cysts/trophozoites was examined by transmission electron microscopy. The sequences of mitochondria] large ribosomal DNA subunit of the cutured organisms were compared with the Pneumocysti carinii f.sp. ratti variant isolate (GenBank No U20173) and Pneumocystis carinii f.sp.hominis (GenBank No M58605). Results Five isolates of P.carinii received from BALF of 8 rats with PCP were cultured axenically and continuously in the system. The cultured organisms could be stored in frozen condition and used to reinitiate culture, and were amplified by 19-22 times within 72 h. The morphology, ultrastructure and gene sequencing of the cultured organisms confirmed that the isolated organisms were P.carinii. Conclusion Five continuously and axenicly cultured isolates of P.carinii have been received.