Germ cells make two major decisions when they move from an indeterminate state to their final stage of gamete production. One decision is sexual commitment for sperm or egg production, and the other is to maintain mitotic division or entry into meiosis. It is unclear whether the two decisions are made as a single event or separate events, because there has been no evidence for the presence of germ cell sex prior to meiosis. Here we report direct evidence in the fish rainbow trout that gonia have distinct sexuality. We show that dazl expression occurs in both male and female gonia but exhibits differential intracellular distribution. More strikingly, we show that boule is highly expressed in male gonia but absent in female gonia. Therefore, mitotic gonia possess sex, sperm/egg decision and mitosis/meiosis decision are two independent events, and sperm/egg decision precedes mitosis/meiosis decision in rainbow trout, making this organism a unique vertebrate model for mechanistic understanding of germ cell sex differentiation and relationship between the two decisions.
Animals ; Female ; Fish Proteins ; genetics ; Gene Expression Regulation ; Male ; Meiosis ; Oncorhynchus mykiss ; genetics ; physiology ; Ovary ; cytology ; metabolism ; Ovum ; cytology ; metabolism ; RNA, Messenger ; genetics ; metabolism ; RNA-Binding Proteins ; genetics ; Sex Determination Processes ; Spermatozoa ; cytology ; metabolism ; Testis ; cytology ; metabolism

Objective:To establish an epidemiological cut-off value (ECV) for antifungal drugs against Cryptococcus neoformans in East China through a multicenter in vitro drug susceptibility test. Methods:A retrospective collection of 479 clinical isolates of Cryptococcus neoformans was conducted by the East China Invasive Fungal Infection Group (ECIFIG) from January 1, 2017 to December 31, 2022. Mass spectrometry and gene sequencing were used for identification. A unified drug susceptibility testing system was established in the fungal laboratories across three sub centers in Shanghai, Jiangxi, and Jiangsu provinces. Drug susceptibility testings of Cryptococcus neoformans were independently completed in each center after passing consistency evaluation. Epidemiological breakpoints were established against fluconazole, voriconazole, amphotericin B, 5-fluorocytosine, isaconazole, posaconazole and itraconazole following the principles and procedures of the Clinical and Laboratory Standards Institute (CLSI) M57. Results:External consistency evaluation revealed that the minimum inhibitory concentration values ??for all drugs in each center did not differ by more than one dilution gradient. A new ECV type of Cryptococcus neoformans in East China was established, including fluconazole 16 mg/L, voriconazole 0.12 mg/L, amphotericin B 1 mg/L, 5-fluorocytosine 8 mg/L, isavuconazole 0.12 mg/L, posaconazole 0.5 mg/L, and itraconazole 0.5 mg/L. Conclusion:This study preliminarily revealed the drug susceptibility characteristics of clinical Cryptococcus neoformans in East China and established the ECVs for antifungal drugs against Cryptococcus neoformans in the region.

Objective To monitor the antifungal resistance of clinical isolates of Candida spp.in the East China region.Methods MALDI-TOF MS or molecular methods were used to re-identify the strains collected from January 2018 to December 2022.Antifungal susceptibility testing was performed using the broth microdilution method.The susceptibility test results were interpreted according to the breakpoints of 2022 Clinical and Laboratory Standards Institute(CLSI)documents M27 M44s-Ed3 and M57s-Ed4.Results A total of 3 026 strains of Candida were collected,65.33％of which were isolated from sterile body sites,mainly from blood(38.86％)and pleural effusion/ascites(10.21％).The predominant species of Candida were Candida albicans(44.51％),followed by Candida parapsilosis complex(19.46％),Candida tropicalis(13.98％),Candida glabrata(10.34％),and other Candida species(0.79％).Candida albicans showed overall high susceptibility rates to the 10 antifungal drugs tested(the lowest rate being 93.62％).Only 2.97％of the strains showed dose-dependent susceptibility(SDD)to fluconazole.Candida parapsilosis complex had a SDD rate of 2.61％and a resistance rate of 9.42％to fluconazole,and susceptibility rates above 90％to other drugs.Candida glabrata had a SDD rate of 92.01％and a resistance rate of 7.99％to fluconazole,resistance rates of 32.27％and 48.24％to posaconazole and voriconazole non-wild-type strains(NWT),respectively,and susceptibility rates above 90％to other drugs.Candida tropicalis had resistance rates of 29.55％and 26.24％to fluconazole and voriconazole,respectively,resistance rates of 76.60％and 21.99％to posaconazole and echinocandins non-wild-type strains(NWT),and a resistance rate of 2.36％to echinocandins.Conclusions The prevalence and species distribution of Candida spp.in the East China region are consistent with previous domestic and international reports.Candida glabrata exhibits certain degree of resistance to fluconazole,while Candida tropicalis demonstrates higher resistance to triazole drugs.Additionally,echinocandins resistance has emerged in Candida albicans,Candida glabrata,Candida tropicalis,and Candida parapsilosis.