Prathap N et al. (2023) Sci Rep "Prosopis juliflora hydrothermal synthesis of high fluorescent carbon dots and its antibacterial and bioimaging applications."

Karuppiah P, Prathap N, Venkatesan S, Shivakumar MS, Balla P, Ramasamy K, Periyasami G

[Sci Rep, 2023]

Carbon dots have stimulated the curiosity of biomedical researchers due to their unique properties, such as less toxicity and high biocompatibility. The synthesis of carbon dots for biomedical application is a core area in research. In the current research, an eco-friendly hydrothermal technique was employed to synthesize high fluorescent, plant-derived carbon dots from Prosopis juliflora leaves extract (PJ-CDs). The synthesized PJ-CDs were investigated by physicochemical evaluation instruments such as fluorescence spectroscopy, SEM, HR-TEM, EDX, XRD, FTIR, and UV-Vis. The UV-Vis absorption peaks obtained at 270 nm due to carbonyl functional groups shifts of n→π*. In addition, a quantum yield of 7.88 % is achieved. The synthesized PJ-CDs showing the presence of carious functional groups O-H, C-H, C=O, O-H, C-N and the obtained particles in spherical shape with an average size of 8 nm. The fluorescence PJ-CDs showed stability against various environmental factors such as a broad range of ionic strength and pH gradient. The antimicrobial activity of PJ-CDs was tested against a Staphylococcus aureus, and a Escherichia coli. The results suggest that the PJ-CDs could substantially inhibit the growth of Staphylococcus aureus. The findings also indicate that PJ-CDs are effective materials for bio-imaging in Caenorhabditis elegans and they can be also used for pharmaceutical applications.

Hodgkin J (2002) Genes Dev "The remarkable ubiquity of DM domain factors as regulators of sexual phenotype: ancestry or aptitude?"

Hodgkin J

[Genes Dev, 2002]

The CM domain is a cysteine-rich DNA-binding motif first recognized in proteins encoded by the Drosophila set determination gene doublesex (Erdman and Burtis 1993; Zhu et al. 2000). As the name doublesex (dsx) suggests, this gene has functions in both sexes: Its transcripts undergo sex-specific alternative splicing, so that it can encode either a male-specific isoform, DSX(M), or a female-specific isoform, DSX(F) (Baker and Wolfner 1988; Burtis and Baker 1989). These proteins have the same N-terminal DNA-binding domain, but different C termini that confer different regulatory properties on the two forms. The expression of DSX(M) directs male development, and the expression of DSX(F) directs female development, throughout most of the somatic tissues of the fruit fly.

Bailey S et al. (2002) Structure "The crystal structure of diadenosine tetraphosphate hydrolase from Caenorhabditis elegans in free and binary complex forms."

Bailey S, Baker PJ, Abdelghany HM, Blackburn GM, Rafferty JB, Sedelnikova SE, McLennan AG

[Structure, 2002]

The crystal structure of C. elegans Ap(4)A hydrolase has been determined for the free enzyme and a binary complex at 2.0 Angstrom. and 1.8 Angstrom, respectively. Ap(4)A hydrolase has a key role in regulating the intracellular Ap(4)A levels and hence potentially the cellular response to metabolic stress and/or differentiation and apoptosis via the Ap(3)A/Ap(4)A ratio. The structures reveal that the enzyme has the mixed alpha/beta fold of the Nudix family and also show how the enzyme binds and locates its substrate with respect to the catalytic machinery of the Nudix motif. These results suggest how the enzyme can catalyze the hydrolysis of a range of related dinucleoside tetraphosphate, but not triphosphate, compounds through precise orientation of key elements of the substrate.

Boule JB et al. (2005) Nature "The yeast Pif1p helicase removes telomerase from telomeric DNA."

Boule JB, Zakian VA, Vega LR

[Nature, 2005]

Telomeres are the physical ends of eukaryotic chromosomes. Genetic studies have established that the baker''s yeast Pif1p DNA helicase is a negative regulator of telomerase, the specialized reverse transcriptase that maintains telomeric DNA, but the biochemical basis for this inhibition was unknown. Here we show that in vitro, Pif1p reduces the processivity of telomerase and releases telomerase from telomeric oligonucleotides. The released telomerase is enzymatically active because it is able to lengthen a challenger oligonucleotide. In vivo, overexpression of Pif1p reduces telomerase association with telomeres, whereas depleting cells of Pif1p increases the levels of telomere-bound Est1p, a telomerase subunit that is present on the telomere when telomerase is active. We propose that Pif1p helicase activity limits telomerase action both in vivo and in vitro by displacing active telomerase from DNA ends.

Calhoun, Adam et al. (2011) International Worm Meeting "Spatial memory in C. Elegans."

Chalasani, Sreekanth, Sharpee, Tatyana, Calhoun, Adam

[International Worm Meeting, 2011]

Worms are known to increase the frequency of turning and reversal events in response to removal of a food stimulus. This keeps the animal in a small area near the last observation of food. The increase in turning frequency is known to be regulated by dopamine and glutamate (Hills et al 2004). We have found that the search strategy is modified by the spatial pattern of food that is experienced. Worms adapt quickly to new food environments, learning spatial patterns on short timescales. The dopamine deficient cat-2 mutant is unable to learn different spatial patterns, suggesting that dopamine is required for spatial memory. References Hills T, Brockie PJ, Maricq AV (2004). Dopamine and glutamate control area-restricted search behavior in Caenorhabditis elegans. J Neurosci 24(5): 1217-1225.

Jantsch V et al. (2004) Mol Cell Biol "Targeted gene knockout reveals a role in meiotic recombination for ZHP-3, a Zip3-related protein in Caenorhabditis elegans."

Schweizer D, Mueller MM, Pasierbek P, Jantsch M, Loidl J, Jantsch V

[Mol Cell Biol, 2004]

The meiotically expressed Zip3 protein is found conserved from Saccharomyces cerevisiae to humans. In baker''s yeast, Zip3p has been implicated in synaptonemal complex (SC) formation, while little is known about the protein''s function in multicellular organisms. We report here the successful targeted gene disruption of zhp-3 (K02B12.8), the ZIP3 homolog in the nematode Caenorhabditis elegans. Homozygous zhp-3 knockout worms show normal homologue pairing and SC formation. Also, the timing of appearance and the nuclear localization of the recombination protein Rad-51 seem normal in these animals, suggesting proper initiation of meiotic recombination by DNA double-strand breaks. However, the occurrence of univalents during diplotene indicates that C. elegans ZHP-3 protein is essential for reciprocal recombination between homologous chromosomes and thus chiasma formation. In the absence of ZHP-3, reciprocal recombination is abolished and double-strand breaks seem to be repaired via alternative pathways, leading to achiasmatic chromosomes and the occurrence of univalents during meiosis I. Green fluorescent protein-tagged C. elegans ZHP-3 forms lines between synapsed chromosomes and requires the SC for its proper localization.

Kathleen Estes et al. (2007) International Worm Meeting "C. elegans vulva development as a model for determining the role of UNC-6 Netrin in tissue morphogenesis."

Kathleen Estes, Wendy Hanna-Rose

[International Worm Meeting, 2007]

UNC-6 Netrin is a well-studied axon guidance molecule. Recently, this protein has been observed acting in morphogenesis of different tissues1. C. elegans unc-6 mutants have a well documented egg-laying defect2. Interestingly, a vulva morphology defect has also been reported but not well-characterized2. We are currently conducting an in-depth phenotypic analysis of the vulva morphology defect in various unc-6 alleles. We are also examining unc-40, the only one of the two well-characterized unc-6 receptors to exhibit an egg-laying defect2. In our initial analysis using an apical junction marker, we have found that the dorsal vulva toroid of unc-6 mutants is severely misshapen and does not seem to display this marker. We also have preliminary data suggesting the anchor cell may not invade the basement membrane, which may contribute to the vulva morphology defect. By studying the phenotype of unc-6 and unc-40 mutants in C. elegans vulva morphogenesis, we can examine this new role of netrin in tissue morphogenesis. 1. reviewed in Baker, et. al. 2006. Curr Opin Neurobiol 16: 529-534 2. Hedgecock, et. al. 1990. Neuron 2: 61-85.

Au C et al. (2008) Neurotoxicology "Manganese transport in eukaryotes: the role of DMT1."

Au C, Benedetto A, Aschner M

[Neurotoxicology, 2008]

Manganese (Mn) is a transition metal that is essential for normal cell growth and development, but is toxic at high concentrations. While Mn deficiency is uncommon in humans, Mn toxicity is known to be readily prevalent due to occupational overexposure in miners, smelters and possibly welders. Excessive exposure to Mn can cause Parkinson''s disease-like syndrome; patients typically exhibit extrapyramidal symptoms that include tremor, rigidity and hypokinesia [Calne DB, Chu NS, Huang CC, Lu CS, Olanow W. Manganism and idiopathic parkinsonism: similarities and differences. Neurology 1994;44(9):1583-6; Dobson AW, Erikson KM, Aschner M. Manganese neurotoxicity. Ann NY Acad Sci 2004;1012:115-28]. Mn-induced motor neuron diseases have been the subjects of numerous studies; however, this review is not intended to discuss its neurotoxic potential or its role in the etiology of motor neuron disorders. Rather, it will focus on Mn uptake and transport via the orthologues of the divalent metal transporter (DMT1) and its possible implications to Mn toxicity in various categories of eukaryotic systems, such as in vitro cell lines, in vivo rodents, the fruitfly, Drosophila melanogaster, the honeybee, Apis mellifera L., the nematode, Caenorhabditis elegans and the baker''s yeast, Saccharomyces cerevisiae.

Kao AW et al. (2011) Proc Natl Acad Sci U S A "A neurodegenerative disease mutation that accelerates the clearance of apoptotic cells."

Cabello J, Kao AW, Neukomm LJ, Farese RV, Eisenhut RJ, Huang A, Bagley JA, Martens LH, Nakamura A, Zhou P, de Luis A, Kenyon C

[Proc Natl Acad Sci U S A, 2011]

Frontotemporal lobar degeneration is a progressive neurodegenerative syndrome that is the second most common cause of early-onset dementia. Mutations in the progranulin gene are a major cause of familial frontotemporal lobar degeneration [Baker M, et al. (2006) Nature 442:916-919 and Cruts M, et al. (2006) Nature 442:920-924]. Although progranulin is involved in wound healing, inflammation, and tumor growth, its role in the nervous system and the mechanism by which insufficient levels result in neurodegeneration are poorly understood [Eriksen and Mackenzie (2008) J Neurochem 104:287-297]. We have characterized the normal function of progranulin in the nematode Caenorhabditis elegans. We found that mutants lacking pgrn-1 appear grossly normal, but exhibit fewer apoptotic cell corpses during development. This reduction in corpse number is not caused by reduced apoptosis, but instead by more rapid clearance of dying cells. Likewise, we found that macrophages cultured from progranulin KO mice displayed enhanced rates of apoptotic-cell phagocytosis. Although most neurodegenerative diseases are thought to be caused by the toxic effects of aggregated proteins, our findings suggest that susceptibility to neurodegeneration may be increased by a change in the kinetics of programmed cell death. We propose that cells that might otherwise recover from damage or injury are destroyed in progranulin mutants, which in turn facilitates disease progression.

Hartman PS et al. (1981) Worm Breeder's Gazette "a mutant with decreased X chromosome meiotic non-disjunction."

Hartman PS, Herman RK

[Worm Breeder's Gazette, 1981]

The mutation mn158 was originally identified on the basis of its conferring hypersensitivity to UV irradiation. Tentatively assigned the gene name rad-4, it has been backcrossed twice to wild type and was positioned about 11 map units to the left of dpy-11 V. rad-4 mutants exhibit a significant decrease in spontaneous meiotic nondisjunction of the X chromosome: 90 broods reared at 25 C yielded 3 males out of 9,689 total self-progeny (0.03%). This compares with 0. 32% obtained at 25 C for N2 (18/5,542). X nondisjunction in him-1( e879); utants was less than 20% of that obtained for him-1; 3.7% (37/1000) for him-1; 1.7% (462/1,457) for him-1. This reduction is not due to a selection against males per se, since rad-4 does not substantially influence X nondisjunction in him-5(e1467) or him-8( e1489) mutants. Moreover, rad-4 male stocks are easily maintained, once established by heat shock. rad-4 appears to be cold sensitive, with high egg inviability at 15 C. Possible allelism with him-7(e1480) and interactions with other him mutants are under investigation. While there are numerous examples of mutations which confer elevated levels of meiotic nondisjunction in C. elegans (Hodgkin et al., 1979, Genetics 91, 67), as well as in many other organisms (Baker et al., 1976, Ann. Rev. Genet. 10, 53), we are unaware of any other mutations that act to reduce nondisjunction.