Deepening our understanding of mammalian gut microbiota has been greatly hampered by the lack of a facile, real‐time, and in vivo bacterial imaging method. To address this unmet need in microbial visualization, we herein report the development of a second near‐infrared (NIR‐II)‐based method for in vivo imaging of gut bacteria. Using d‐propargylglycine in gavage and then click reaction with an azide‐containing NIR‐II dye, gut microbiota of a donor mouse was strongly labeled with NIR‐II fluorescence on their peptidoglycan. The bacteria could be readily visualized in recipient mouse gut with high spatial resolution and deep tissue penetration under NIR irradiation. The NIR‐II‐based metabolic labeling strategy reported herein, provides, to the best of our knowledge, the first protocol for facile in vivo visualization of gut microbiota within deep tissues, and offers an instrumental tool for deciphering the complex biology of these gut “dark matters”.

ObjectiveMutations in the type II collagen gene are associated with certain human disorders, collectively termed type II collagenopathies. They include Legg–Calvé–Perthes disease (LCPD) and avascular necrosis of the femoral head (ANFH). These two diseases are skeletal dysplasias, inherited in an autosomal dominant fashion, characterized by groin pain, dislocation of the hip and diminished joint mobility. Coxa vara and elevation of the greater trochanter of the femur comprise the typical phenotype of LCPD, but do not occur in ANFH. Lack of synthesis of type II collagen and structural defects are responsible for the major clinical outcomes, because collagen is the essential matrix protein of all connective tissues. Type II collagen, encoded by the COL2A1 gene, contains N- and C- terminal regions that are cleaved after secretion into the extracellular matrix, and the core area is composed of a triple helical (Gly–X–Y) domain. If the Gly in this specific region is replaced by other amino acids, the structure of type II collagen will be destroyed.MethodForty-five members of a four-generation family were recruited and investigated. Diagnosis was made by independent orthopedic surgeons and radiologists. A mutation of the COL2A1 gene was detected.ResultIn our research, we identify a heterozygous mutation (c.1888 G>A, p. Gly630Ser) in exon 29 of COL2A1 in the Gly–X–Y domain, in a Chinese family affected by LCPD and ANFH. Our findings provide significant clues to the phenotype–genotype relationships in these syndromes and may be helpful in clinical diagnosis. Furthermore, these results should assist further studies of the mechanisms underlying collagen diseases.ConclusionOur data add new variants to the repertoire of COL2A1 mutation resulting in related collagenopathies.

BackgroundTo review the possible mechanisms proposed to explain the etiology of 46, XX sex reversal by investigating the clinical characteristics and their relationships with chromosomal karyotype and the SRY(sex-determining region Y)gene.MethodsFive untreated 46, XX patients with SRY-positive were referred for infertility. Clinical data were collected, and Karyotype analysis of G-banding in lymphocytes and Fluorescence in situ hybridization (FISH) were performed. Genomic DNA from peripheral blood of the patients using QIAamp DNA Blood Kits was extracted. The three discrete regions, AZFa, AZFb and AZFc, located on the long arm of the Y chromosome, were performed by multiplex PCRs(Polymerase Chain Reaction) amplification. The set of PCR primers for the diagnosis of microdeletion of the AZFa, AZFb and AZFc region included: sY84, sY86, sY127, sY134, sY254, sY255, SRY and ZFX/ZFY.ResultsOur five patients had a lower body height. Physical examination revealed that their testes were small in volume, soft in texture and normal penis. Semen analyses showed azoospermia. All patients had a higher follicle-stimulating hormone(FSH), Luteinizing Hormone(LH) level, lower free testosterone, testosterone level and normal Estradiol, Prolactin level. Karyotype analysis of all patients confirmed 46, XX karyotype, and FISH analysis showed that SRY gene were positive and translocated to Xp. Molecular analysis revealed that the SRY gene were present, and the AZFa, AZFb and AZFc region were absent.ConclusionsThis study adds cases on the five new 46, XX male individuals with SRY-positive and further verifies the view that the presence of SRY gene and the absence of major regions in Y chromosome should lead to the expectance of a completely masculinised phenotype, abnormal hormone levels and infertility.