Transcriptomic Analysis of Large Yellow Croaker (Larimichthys crocea) during Early Development under Hypoxia and Acidification Stress.

Fishes live in aquatic environments and several aquatic environmental factors have undergone recent alterations. The molecular mechanisms underlying fish responses to hypoxia and acidification stress have become a serious concern in recent years. This study revealed that hypoxia and acidification stress suppressed the growth of body length and height of the large yellow croaker (Larimichthys crocea). Subsequent transcriptome analyses of L. crocea juveniles under hypoxia, acidification, and hypoxia-acidification stress led to the identification of 5897 differentially expressed genes (DEGs) in the five groups. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that several DEGs were enriched in the 'protein digestion and absorption' pathway. Enrichment analysis revealed that this pathway was closely related to hypoxia and acidification stress in the five groups, and we found that genes of the collagen family may play a key role in this pathway. The zf-C2H2 transcription factor may play an important role in the hypoxia and acidification stress response, and novel genes were additionally identified. The results provide new clues for further research on the molecular mechanisms underlying hypoxia-acidification tolerance in L. crocea and provides a basic understanding of the potential combined effects of reduced pH and dissolved oxygen on Sciaenidae fishes.

Schizophrenia Spectrum Disorders Show Reduced Specificity and Less Positive Events in Mental Time Travel.

Mental time travel refers to the ability to recall past events and to imagine possible future events. Schizophrenia (SCZ) patients have problems in remembering specific personal experiences in the past and imagining what will happen in the future. This study aimed to examine episodic past and future thinking in SCZ spectrum disorders including SCZ patients and individuals with schizotypal personality disorder (SPD) proneness who are at risk for developing SCZ. Thirty-two SCZ patients, 30 SPD proneness individuals, and 33 healthy controls participated in the study. The Sentence Completion for Events from the Past Test (SCEPT) and the Sentence Completion for Events in the Future Test were used to measure past and future thinking abilities. Results showed that SCZ patients showed significantly reduced specificity in recalling past and imagining future events, they generated less proportion of specific and extended events compared to healthy controls. SPD proneness individuals only generated less extended events compared to healthy controls. The reduced specificity was mainly manifested in imagining future events. Both SCZ patients and SPD proneness individuals generated less positive events than controls. These results suggest that mental time travel impairments in SCZ spectrum disorders and have implications for understanding their cognitive and emotional deficits.

Neural correlates of prospective memory impairments in schizophrenia.

OBJECTIVE: Prospective memory (PM) refers to the ability to remember to carry out intended actions after a delay. PM impairments are common in schizophrenia patients and are thought to be related to their prefrontal cortex dysfunction; however, this has not yet been examined directly in the research literature. The current study aimed to examine abnormalities in brain activation during PM task performance in schizophrenia patients. METHOD: Twenty-two schizophrenia patients and 25 matched healthy controls were scanned in a 3-T MRI machine while performing a PM task. RESULTS: The results showed that compared to the healthy controls, schizophrenia patients performed significantly worse on the PM task. Furthermore, they exhibited decreased brain activation in frontal cortex including the right superior frontal gyri (Brodmann area 10), and other related brain areas like the anterior cingulate gyrus, parietal and temporal cortex, including precuneus, and some subcortext, including parahippocampal gyrus and putamen. CONCLUSIONS: These findings confirm the involvement and importance of the prefrontal cortex in PM and show evidence of hypofrontality in schizophrenia patients while performing a PM task.

Breakdown of the striatal-default mode network loop in schizophrenia.

The striatum has been shown to be a core region in schizophrenia with functional and structural deficits. Previous studies have confirmed the schizophrenia-related functional connectivity between the striatal and cortical regions. However, among these, few studies have attempted to determine the directional flow of the influence. In the present study, we used resting-state fMRI to explore the directed connectivity between the striatum and the cortical regions in schizophrenia. Employing a Granger causality analysis, we observed a significant failure of the directed inhibitory influence of the striatum on the default mode network (DMN) in schizophrenia. Furthermore, the reciprocal influence of the DMN on the striatum was also significantly reduced. These findings provide compelling evidence for a breakdown of the striatum-DMN loop in schizophrenia. This abnormal connectivity could be related to clinical variables. In conclusion, our study suggests that abnormally directed influences between the striatum and the DMN might be a biomarker of schizophrenia and also reveals a potential target for treatment.

Comparative analysis of the transcriptome in tissues secreting purple and white nacre in the pearl mussel Hyriopsis cumingii.

The triangle sail mussel Hyriopsis cumingii (Lea) is the most important mussel species used for commercial freshwater pearl production in China. Mussel color is an important indicator of pearl quality. To identify genes involved in the nacre coloring, we conducted RNA-seq and obtained 541,268 sequences (298 bp average size) and 440,034 sequences (293 bp average size) in secreting purple and white nacre libraries (P- and W-libraries), respectively. The 981,302 Expressed Sequence Tags (ESTs) were assembled into 47,812 contigs and 289,386 singletons. In BLASTP searches of the deduced protein, 22,495 were proteins with functional annotations. Thirty-three genes involved in pearl or shell formation were identified. Digital expression analysis identified a total of 358 differentially expressed genes, and 137 genes in the P-library and 221 genes in the W-library showed significantly higher expression. Furthermore, a set of SSR motifs and SNPs between the two samples was identified from the ESTs, which provided the markers for genetic linkage, QTL analysis and future breeding. These EST sequences provided valuable information to further understand the molecular mechanisms involved in the formation, color determination and evolution of the pearl or shell.