Objective To establish a pure planarian Dugesiaasexual strain in China.Methods The planarian worms were collected from a wild stream,and then made the worm grow after amputation in the lab.To establish an asexual strain through cutting and culturing for the single worms.Results After ten years and more than ten thousand experiments,an asexual pure planarian strain Dugesia ZB-1 originated from Shandong Zibo area was established.It grows stably under laboratory controlled conditions.Conclusions The establishment of DugesiaZB-1 Priovides a solid foundation for further experiments and promoting planarian research in our country and participation in the field of the international planarian research.

Objective To investigate the expressions of guanylyl cyclase-c(GC-C) and caudal-type homeobox transcription factor 2 (CDX2) in human gastric tissues and precursor lesions and its significance. Methods The cancerous and paracancerous (5 cm from cancer lesion )samples from 30 cases of gastric cancer and 32 samples including 23 intestinal metaplasia and 9 dysplasia were collected. The mRNA expressions of GC-C and CDX-2 were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and proteins of GC-C and CDX-2 were measured by using Western blot and immunofluorescence methods. Results The mRNA expressions of GC-C and CDX-2 were absent in paracancerous tissues, but were 66.7% and 63.3% in cancerous tissues, respectively(P=0. 000). The Western blot indicated that expressions of GC-C and CDX-2 were 19/30 and 17/30 in cancerous tissues, but absent in paracancerous tissues(P=0. 000). The immunofluorescence examination revealed that GC-C and CDX-2 expressions were 39.1% and 39.1% in intestinal metaplasia, 55.6% and 55.6% in dysplasia, and 56.7% and 60.0% in cancerous tissues, respectively, but absent in paracancerous tissues. Moreover, expressions of GC-C and CDX-2 showed a statistical difference between intestinal-type and diffuse-type of gastric cancer (P＜ 0.05) ,but had no correlation with age, sex, size of the lesion, clinical stage and lymphnode metastasis. The positive correlation was found in expressions of GC-C and CDX2 between intestinal metaplasia and cancerous tissues(r=0. 4524 and 0. 3845, P= 0. 037 and 0. 0408, respectively). Conclusions The over expressions of GC-C and CDX2 in human gastric cancer is associated with precursor lesions and may play an important role in the carcinogenesis of gastric cancer. The examination of GC-C and CDX2 expressions will be helpful in diagnosing gastric cancer and precursor lesions.

Coronaviruses (CoVs), a family of enveloped positive-sense RNA viruses, are characterized by club-like spikes that project from their surface, unusually large RNA genome, and unique replication capability. CoVs are known to cause various potentially lethal human respiratory infectious diseases, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the very recent coronavirus disease 2019 (COVID-19) outbreak. Unfortunately, neither drug nor vaccine has yet been approved to date to prevent and treat these diseases caused by CoVs. Therefore, effective prevention and treatment medications against human coronavirus are in urgent need. In the past decades, many natural compounds have been reported to possess multiple biological activities, including antiviral properties. In this article, we provided a comprehensive review on the natural compounds that interfere with the life cycles of SARS and MERS, and discussed their potential use for the treatment of COVID-19.