Rumi is a CAP10 domain glycosyltransferase that modifies Notch and is required for Notch signaling

Notch signaling is broadly used to regulate cell-fate decisions. We have identified a gene, rumi, with a temperature-sensitive Notch phenotype. At 28 degrees C-30 degrees C, rumi clones exhibit a full-blown loss of Notch signaling in all tissues tested. However, at 18 degrees C only a mild Notch phenotype is evident. In vivo analyses reveal that the target of Rumi is the extracellular domain of Notch. Notch accumulates intracellularly and at the cell membrane of rumi cells but fails to be properly cleaved, despite normal binding to Delta. Rumi is an endoplasmic reticulum-retained protein with a highly conserved CAP10 domain. Our studies show that Rumi is a protein O-glucosyltransferase, capable of adding glucose to serine residues in Notch EGF repeats with the consensus C1-X-S-X-P-C2 sequence. These data indicate that by O-glucosylating Notch in the ER, Rumi regulates its folding and/or trafficking and allows signaling at the cell membrane.     

Studies on the biosynthesis of the carane skeleton

Measurements of isotope ratios in car-3-ene biosynthesized in Pinus sylvestris from (3RS)-mevalonate-[2-¹⁴C,2R-³H₁], and [2-¹⁴C,4R-³H₁] and the corresponding S-epimers and also from geraniol- [¹⁴C,1-³H₂] and nerol-[¹⁴ C,1-³H₂] have shown that the carane skeleton is constructed from its presumed monocyclic precursor with migration of an olefinic bond, together with an unexpected 1,2-shift of a proton to the site of the original double bond. The detailed stereochemistry of the processes allows a two-step mechanism to be inferred for the cyclization in which a bonded intermediate is involved. The conversion of geraniol into nerol (en route to car-3-ene) probably is a redox process with the intermediacy of the corresponding aldehydes. The present results eliminate a possible mechanism for this isomerization wherein cyclopropane derivatives occur as intermediates.     

Biosynthesis of carvone in Mentha spicata

Degradation of, and measurement of isotope ratios in, (?)-carvone that had been biosynthesized in Mentha spicata from ³H- and ¹⁴C-labelled geraniol and mevalonate indicate that (a) oxidation of limonene or its biogenetic equivalent to form carvone involves shift of the endocyclic double bond; (b) (+)-limonene and (?)-carvone are biogenetically related and are probably formed on divergent pathways from a common intermediate; and (c) the exocyclic double bond of carvone is not formed regiospecifically. These results enable the mechanisms for the introduction of the carbonyl group and for the formation of the isopropenyl side-chain to be delimited.     

UV-B Priming of Oryza sativa Seeds Augments the Innate Tolerance Potential in a Tolerant Variety more Effectively Toward NaCl and PEG Stressors

Journal of Plant Growth Regulation - NaCl and polyethylene glycol-6000 (PEG) stressors are the major limitation factors for successful seedling establishment in rice. The present study was carried...     

Incidence of Subclinical Mastitis and Prevalence of Major Mastitis Pathogens in Organized Farms and Unorganized Sectors

Subclinical mastitis (SCM) represents a major proportion of the burden of mastitis. Determining somatic cell count (SCC) and electrical conductivity (EC) of milk are useful approaches to detect SCM. In order to correlate grades of SCM with the load of five major mastitis pathogens, 246 milk samples from a handful of organized and unorganized sectors were screened. SCC (>5 × 10⁵/mL) and EC (>6.5 mS/cm) identified 110 (45 %) and 153 (62 %) samples, respectively, to be from SCM cases. Randomly selected SCM-negative samples as well as 186 samples positive by either SCC or EC were then evaluated for isolation of five major mastitis-associated bacteria. Of the 323 isolates obtained, 95 each were S. aureus and coagulase-negative staphylococci (CoNS), 48 were E. coli and 85 were streptococci. There was no association between the distribution of organisms and (a) the different groups of SCC, or (b) organised farms and unorganised sectors. By contrast, there was a significant difference in the distribution of CoNS, and not other species, between organized farms and unorganized sectors. In summary, bacteria were isolated irrespective of the density of somatic cells or the type of farm setting, and the frequency of isolation of CoNS was higher with organized farms. These results suggest the requirement for fine tuning SCC and EC limits and the higher probability for CoNS to be associated with SCM in organized diary sectors, and have implications for the identification, management and control of mastitis in India.     

Rich regulates target specificity of photoreceptor cells and N-cadherin trafficking in the Drosophila visual system via Rab6

Neurons establish specific synaptic connections with their targets, a process that is highly regulated. Numerous cell adhesion molecules have been implicated in target recognition, but how these proteins are precisely trafficked and targeted is poorly understood. To identify components that affect synaptic specificity, we carried out a forward genetic screen in the Drosophila eye. We identified a gene, named ric1 homologue (rich), whose loss leads to synaptic specificity defects. Loss of rich leads to reduction of N-Cadherin in the photoreceptor cell synapses but not of other proteins implicated in target recognition, including Sec15, DLAR, Jelly belly, and PTP69D. The Rich protein binds to Rab6, and Rab6 mutants display very similar phenotypes as the rich mutants. The active form of Rab6 strongly suppresses the rich synaptic specificity defect, indicating that Rab6 is regulated by Rich. We propose that Rich activates Rab6 to regulate N-Cadherin trafficking and affects synaptic specificity.     

Deciphering the genetic architecture and ethnographic distribution of IRD in three ethnic populations by whole genome sequence analysis

Patients with inherited retinal dystrophies (IRDs) were recruited from two understudied populations: Mexico and Pakistan as well as a third well-studied population of European Americans to define the genetic architecture of IRD by performing whole-genome sequencing (WGS). Whole-genome analysis was performed on 409 individuals from 108 unrelated pedigrees with IRDs. All patients underwent an ophthalmic evaluation to establish the retinal phenotype. Although the 108 pedigrees in this study had previously been examined for mutations in known IRD genes using a wide range of methodologies including targeted gene(s) or mutation(s) screening, linkage analysis and exome sequencing, the gene mutations responsible for IRD in these 108 pedigrees were not determined. WGS was performed on these pedigrees using Illumina X10 at a minimum of 30X depth. The sequence reads were mapped against hg19 followed by variant calling using GATK. The genome variants were annotated using SnpEff, PolyPhen2, and CADD score; the structural variants (SVs) were called using GenomeSTRiP and LUMPY. We identified potential causative sequence alterations in 61 pedigrees (57%), including 39 novel and 54 reported variants in IRD genes. For 57 of these pedigrees the observed genotype was consistent with the initial clinical diagnosis, the remaining 4 had the clinical diagnosis reclassified based on our findings. In seven pedigrees (12%) we observed atypical causal variants, i.e. unexpected genotype(s), including 4 pedigrees with causal variants in more than one IRD gene within all affected family members, one pedigree with intrafamilial genetic heterogeneity (different affected family members carrying causal variants in different IRD genes), one pedigree carrying a dominant causative variant present in pseudo-recessive form due to consanguinity and one pedigree with a de-novo variant in the affected family member. Combined atypical and large structural variants contributed to about 20% of cases. Among the novel mutations, 75% were detected in Mexican and 50% found in European American pedigrees and have not been reported in any other population while only 20% were detected in Pakistani pedigrees and were not previously reported. The remaining novel IRD causative variants were listed in gnomAD but were found to be very rare and population specific. Mutations in known IRD associated genes contributed to pathology in 63% Mexican, 60% Pakistani and 45% European American pedigrees analyzed. Overall, contribution of known IRD gene variants to disease pathology in these three populations was similar to that observed in other populations worldwide. This study revealed a spectrum of mutations contributing to IRD in three populations, identified a large proportion of novel potentially causative variants that are specific to the corresponding population or not reported in gnomAD and shed light on the genetic architecture of IRD in these diverse global populations.