Gut Microbiota-Mediated Immunomodulatory Effects of Lactobacillus rhamnosus HDB1258 Cultured in the Lava Seawater in the Colitis Mouse Model.

The immunomodulatory effects of Lactobacillus rhamnosus HDB1258 were evaluated in mice with colitis induced by Klebsiella oxytoca (KO). L. rhamnosus HDB1258 was cultured in the lava seawater (LS) to improve its probiotic properties. It increased adhesive ability to mucin with mRNA expression levels of chaperone proteins (such as GroEL/ES, DnaKJ, and HtrA). In the in vivo experiments, administration of KO caused an inflammation on the colon with gut dysbiosis. LH group (oral gavage of HDB1258 1.0 × 109 colony forming units/day) showed that inflammatory biomarkers, including IL-1ß, TNF-α, IL-6, and PGE2, were significantly decreased to less than half of the KO group, and Th1 cells were decreased in the spleen, but Treg cells were not affected. In contrast, the expression levels of secretory IgA and IL-10 were significantly increased, and the composition of gut microbiota in the LH group tended to recover similar to normal mice without any effect on the α-diversity. In conclusion, L. rhamnosus HDB1258 cultured in the LS could regulate competitively pathogenic bacteria in imbalanced flora with its improved mucin adhesive ability and was an effective immunomodulatory adjuvant for treating colitis by its regulatory function on intestinal inflammation.

The rice gene DEFECTIVE TAPETUM AND MEIOCYTES 1 (DTM1) is required for early tapetum development and meiosis.

Tapetum development and meiosis play crucial roles in anther development. Here we identified a rice gene, DEFECTIVE TAPETUM AND MEIOCYTES 1 (DTM1), which controls the early stages of that development. This gene encodes for an endoplasmic reticulum (ER) membrane protein that is present only in cereals. Our T-DNA insertion mutations gave rise to abnormal tapetal formation. Cellular organelles, especially the ER, were underdeveloped, which led to hampered differentiation and degeneration of the tapetum. In addition, the development of pollen mother cells was arrested at the early stages of meiotic prophase I. RNA in-situ hybridization analyses showed that DTM1 transcripts were most abundant in tapetal cells at stages 6 and 7, and moderately in the pollen mother cells and meiocytes. Transcripts of UDT1, which functions in tapetum development during early meiosis, were reduced in dtm1 anthers, as were those of PAIR1, which is involved in chromosome pairing and synapsis during meiosis. However, expression of MSP1 and MEL1, which function in anther wall specification and germ cell division, respectively, was not altered in the dtm1 mutant. Moreover, transcripts of DTM1 were reduced in msp1 mutant anthers, but not in udt1 and pair1 mutants. These results, together with their mutant phenotypes, suggest that DTM1 plays important roles in the ER membrane during early tapetum development, functioning after MSP1 and before UDT1, and also in meiocyte development, after MEL1 and before PAIR1.

Rice Immature Pollen 1 (RIP1) is a regulator of late pollen development.

We isolated a pollen-preferential gene, RICE IMMATURE POLLEN 1 (RIP1), from a T-DNA insertional population of japonica rice that was trapped by a promoterless beta-glucuronidase (GUS) gene. Semi-quantitative reverse transcription-PCR (RT-PCR) analyses confirmed that the RIP1 transcript was abundant at the late stages of pollen development. Transgenic plants carrying a T-DNA insertion in the RIP1 gene displayed the phenotype of segregation distortion of the mutated rip1 gene. Moreover, rip1/rip1 homozygous progeny were not present. Reciprocal crosses between Rip1/rip1 heterozygous plants and the wild type showed that the rip1 allele could not be transmitted through the male. Microscopic analysis demonstrated that development in the rip1 pollen was delayed, starting at the early vacuolated stage. Close examination of that pollen by transmission electron microscopy also showed delayed formation of starch granules and the intine layer. In addition, development of the mitochondria, Golgi apparatus, lipid bodies, plastids and endoplasmic reticulum was deferred in the mutant pollen. Under in vitro conditions, germination of this mutant pollen did not occur, whereas the rate for wild-type pollen was >90%. These results indicate that RIP1 is necessary for pollen maturation and germination. This gene encodes a protein that shares significant homology with a group of proteins containing five WD40 repeat sequences. The green fluorescent protein (GFP)-RIP1 fusion protein is localized to the nucleus. Therefore, RIP1 is probably a nuclear protein that may form a functional complex with other proteins and carry out essential cellular and developmental roles during the late stage of pollen formation.