Precise regulation of stem cell activity is crucial for tissue homeostasis. In Drosophila, intestinal stem cells (ISCs) maintain the midgut epithelium and respond to oxidative challenges. However, the connection between intestinal homeostasis and redox signaling remains obscure. Here we find that Caliban (Clbn) functions as a regulator of mitochondrial dynamics in enterocytes (ECs) and is required for intestinal homeostasis. The clbn knock-out flies have a shortened lifespan and lose the intestinal homeostasis. Clbn is highly expressed and localizes to the outer membrane of mitochondria in ECs. Mechanically, Clbn mediates mitochondrial dynamics in ECs and removal of clbn leads to mitochondrial fragmentation, accumulation of reactive oxygen species, ECs damage, activation of JNK and JAK-STAT signaling pathways. Moreover, multiple mitochondria-related genes are differentially expressed between wild-type and clbn mutated flies by a whole-genome transcriptional profiling. Furthermore, loss of clbn promotes tumor growth in gut generated by activated Ras in intestinal progenitor cells. Our findings reveal an EC-specific function of Clbn in regulating mitochondrial dynamics, and provide new insight into the functional link among mitochondrial redox modulation, tissue homeostasis and longevity.

We investigated Pneumocystis jirovecii dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) genes for mutations in 25 Chinese HIV-infected patients with P. jirovecii pneumonia. We identified DHPS mutations in 3 (12%) patients and DHFR mutations in 1 (4%) patient. The prevalence of DHPS and DHFR mutations in China remains low, as it does in other developing countries.

Indosasa lipoensis, an ornamental garden plant, belongs to the Indosasa genus of the subfamily Bambooaceae within Poaceae. Indosasa lipoensis is endangered and requires protection owing to its relatively narrow distribution area. Chloroplast (cp) genome offers a novel awareness of the evolutionary and genetic variation of higher plants. Herein, we assembled and elucidated the complete cp genome of I. lipoensis, and compared it with four previously published cp genomes from this genus. The I. lipoensis cp genome was 139,655 bp in size, with a typical quadripartite structure, encompassing a large single-copy region (LSC, 83,256 bp), a small single-copy region (SSC, 12,809 bp), and a pair of inverted repeat regions (IR, 21,795 bp). The cp genome consisted of 130 genes with 84 protein-coding genes (CDS), 38 tRNA genes, and 8 rRNA genes. The plastomes were highly conservative, compared to other bamboo species, and exhibited similar patterns of codon usage, number of repeat sequences, and expansion and contraction of the IR boundary. Five hypervariable hotspots were identified as potential DNA barcodes, namely rbcL, petA, petB, trnL-UAG, and ndhE-ndhI, respectively. Phylogenetic analysis based on the complete cp genomes revealed, with high resolution, that I. lipoensis and I. gigantea were most closely related. Overall, these results provided valuable characterization for the future conservation, genetic evaluation, and the breeding of I. lipoensis.

No abstract

Chimonobambusa hirtinoda, a threatened species, is only naturally distributed in Doupeng Mountain, Duyun, Guizhou, China. Next-generation sequencing (NGS) is used to obtain the complete chloroplast (cp) genome sequence of C. hirtinoda. The sequence was assembled and analyzed for phylogenetic and evolutionary studies. Additionally, we compared the cp genome of C. hirtinoda with previously published Chimonobambusa species. The cp genome of C. hirtinoda has a total length of 139, 561 bp and 38.90% GC content. This genome included a large single -copy (LSC) region of 83, 166 bp, a small single-copy (SSC) region of 20, 811 bp and a pair of inverted repeats of 21,792 bp each. We discovered 130 genes in the cp genome, including 85 protein-coding genes, 37 tRNA, and 8 rRNA genes. A total of 48 simple sequence repeats (SSRs) were detected. The A/U preference of the third nucleotide in the cp genome of C. hirtinoda was obtained by measuring the codon usage frequency of amino acids. Furthermore, phylogenetic analysis using complete cp sequences and matK gene revealed a genetic relationship within the Chimonobambusa genus. This study reported the chloroplast genome of the C. hirtinoda.