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Quasiparticle poisoning, expected to arise during the measurement of the Majorana zero-mode state, poses a fundamental problem for the realization of Majorana-based quantum computation. Parafermions, a natural generalization of Majorana fermions, can encode topological qudits immune to quasiparticle poisoning. While parafermions are expected to emerge in superconducting fractional quantum Hall systems, they are not yet attainable with current technology. To bypass this problem, we employ a photonic quantum simulator to experimentally demonstrate the key components of parafermion-based universal quantum computation. Our contributions in this paper are twofold. First, by manipulating the photonic states, we realize Clifford-operator Berry phases that correspond to braiding statistics of parafermions. Second, we investigate the quantum contextuality in a topological system for the first time by demonstrating the contextuality of parafermion-encoded qudit states. Importantly, we find that the topologically encoded contextuality opens the way to magic state distillation, while both the contextuality and the braiding-induced Clifford gates are resilient against local noise. By introducing contextuality, our photonic quantum simulation provides the first step toward a physically robust methodology for realizing topological quantum computation.

Setosabatieria major sp. nov. (Figures 3, 4 and Table 2) Type material Five males, one female and one juvenile from station CC4. Holotype: ♂ 1 on slide number Chukchi20100720 CC42401. Paratypes: ♂ 2 on slide number Chukchi20100720 CC42401, ♂ 3 on Chukchi20100720 CC42403, ♂ 4 on Chukchi20100720 CC42404, ♂ 5 on Chukchi20100720 CC42405, ♀ 1 on Chukchi20100720 CC42406, juvenile on Chukchi20100720 CC42407. Type locality and habitat Sublittoral zone in the Chukchi Sea (the Arctic Ocean). Latitude: 68.1336°N, longitude: 167.8633°W. Environmental parameters: water depth 52 m, surface water temperature 2.2°C, salinity at 52 m depth 32.13 ‰. Etymology This species is named for the large body. Measurements Measurements are given in Table 2. – 366 W 2806 Holotype ♂ 1: 3130 µm; a = 18.6, b = 8.6, c = 9.7, Spic = 69 µm 21 117 168 82 – 332 V 2828 Paratype ♀ 1: 3145 µm; a = 17.9, b = 9.5, c = 8.0, V % = 44.1% 23 104 176 80 Description Body rather large cylindrical, tapering towards both extremities. Cuticle not punctated but with transverse striation most obvious at anterior and posterior extremities. Buccal cavity small cup-shaped, surrounded by six short outer labial, 1.5 – 2 μm long and four cephalic setae, 9 – 13 μm long. Amphidial fovea spiral, with 3.25 – 3.75 turns and occupying 47 – 57% of corresponding body diameter. Four sublateral rows of 10 – 11 cervical setae 8 – 10 μm long. Pharynx gradually swollen posteriorly, not forming a true bulb. Cardia small, muscular, surrounded by intestinal tissue. Ventral gland situated posterior to pharynx and excretory pore about level nerve ring. Nerve ring at 55 – 61% of pharynx length from anterior end. Tail slender, with rather broad, conical anterior portion and rather narrow cylindrical posterior portion. Tail 3.7 – 4.5 times of the anal body diameter with numerous short setae. Tail tip not enlarged, with 15 µm long three terminal setae. Caudal glands not always visible and spinneret well developed. Males. Reproductive system with two opposite outstretched testes. Spicules paired, equal, slight arcuate, 0.9 – 1.3 times as long as cloacal body diameter, with central septum appearing in both proximal and distal portions. Gubernaculum with a pair of short dorsocaudal apophyses. There are 26 – 28 small pre-cloacal papillae supplements, although they are very small and difficult to observe. Females. Similar to male in general characteristics, but tail with fewer short setae and narrow cylindrical posterior portion longer than anterior conical portion. Reproductive system with two outstretched equally developed ovaries. Vulva at 44% of total body length. Differential diagnosis Setosabatieria major sp. nov. is characterized by its rather large body (length 2700 – 3145 µm; maximum body diameter 106 – 176 µm), the number (10 – 11) of cervical setae per file, 26 – 28 small papillate precloacal supplements and central septum appearing in both proximal and distal portions of spicules. These characters are obviously different from those of other species in this genus.

Setosabatieria longiapophysis sp. nov. (Figures 1, 2 and Table 1) Type material Five males and two females were collected from station XMGLY L2. Holotype: ♂ 1 on slide number XMGLY 20111016 L206. Paratypes: ♂ 2 and ♀ 2 on slide number XMGLY 20111016 L205, ♂ 3 on XMGLY 20111016 L210, ♂ 4 on XMGLY 20111016 L218, ♂ 5 and ♀ 1 on XMGLY 20111016 L213. Type locality and habitat Intertidal sandy sediment at Gulang Island, Xiamen, the East China Sea. Latitude: 118.0666°E, longitude: 24.4333°N. Characteristics of surface sediment: Silt + clay 0.07%, salinity 20 – 22 ‰, total organic matter 0.0192%. Etymology This species is named for the long straight apophyses of gubernaculum. Measurements Measurements are given in Table 1. – 252 W 2273 Holotype ♂ 1: 16 41 49 39 2480 µm; a = 50.6, b = 9.8, c = 12.0, Spic = 66.0 µm – 270 V 2312 Paratype ♀ 1: 2540 µm; a = 49.8, b = 9.4, c = 11.2, V % = 50.0% 16 41 51 38 Description Body cylindrical, tapering towards both extremities, maximum body diameter 42 – 58 µm. Cuticle not punctate but with faint transverse striations visible throughout body. Head narrower than rest of body due to constriction at level of amphidial fovea. Buccal cavity cup-shaped. Inner labial sensilla not visible, outer labial sensilla setiform, 2 μm long. Four cephalic setae 16 – 19 µm long (100 – 120% of head diameter). Cervical setae, similar to cephalic setae length, arranged in four longitudinal files of seven to nine setae. Amphidial fovea spiral, with 2.75 – 3 turns, 15 – 17 µm in diameter, occupying 49 – 69% of corresponding body diameter. Pharynx gradually enlarging posteriorly but without true terminal bulb. Nerve ring at 61 – 65% of pharynx length from anterior end. Cardia small, muscular, surrounded by intestinal tissue. Excretory pore posterior to nerve ring. Tail conico-cylindrical, 5.3 – 6.0 times anal body diameter, with numerous caudal setae. Tail tip enlarged with three terminal setae 12 µm long. Caudal glands and spinneret well developed. Males. Testes opposite and outstretched. Anterior testis situated to left of intestine, posterior testis to right. Spicules paired, equal, arcuate, with slightly marked capitulum and a central cuticularized septum at the proximal end. Gubernaculum with 31 – 37 µm long straight dorsocaudal directed apophyses. Fifteen or 16 poorly developed small precloacal papillate supplements, posterior supplements with closer spacing. Females. Similar to male in general characteristics, but amphid diameter smaller; vulva at 49 – 50% of total body length but developed reproductive system not found. Differential diagnosis Setosabatieria longiapophysis sp. nov. is similar to Setosabatieria triangularis Riera et al. 2006 in that they both have longer cephalic setae than in the other species, and a similar number of cervical setae in each sublateral row and precloacal supplements (Table 3). However, Setosabatieria longiapophysis sp. nov. has spicules with straight apophyses 31 – 37 µm long in contrast to the triangular apophyses of S. triangularis.

Infection of host cells with human cytomegalovirus (HCMV) induces cell cycle dysregulation. Two HCMV immediate-early (IE) proteins, IE1-72 and IE2-86, are promiscuous transactivators that have been implicated in the dysregulatory events. Cellular p53 protein is accumulated to high levels in HCMV-infected cells, but the indicative marker of p53 transcriptional activity, p21, is markedly decreased. Both IE1-72 and IE2-86 were able to transactivate the p53 promoter and interact with p53 protein in DNA-transfected or HCMV-infected cells. HCMV UL84, a multiregulatory protein expressed in early periods of HCMV infection, also interacted with p53. HCMV IE1-72 prevented or disrupted p53 binding to p53-specific DNA sequences, while IE2-86 and/or UL84 enhanced p53 binding and induced supershift of this DNA-protein complex. Both HCMV IE1-72 and IE2-86 were able to inhibit p53-dependent transcriptional activation in plasmid-transfected cells. IE1-72, rather than IE2-86, was found to be responsible for p21 downregulation in HCMV-infected HEL cells. DNA transfection analysis using IE1-72 mutants revealed that exon 2/3 and the zinc finger region of IE1-72 are essential for IE1-72's effect on the repression of p53-dependent transcriptional activation. These data suggest that HCMV IE1-72 and/or IE2-86 transactivates the p53 promoter and induces p53 accumulation, but HCMV IE1-72 represses the p53 transactivation activity by a unique binding hindrance mechanism different from that of IE2-86. Thus, various modes of viral IE proteins and p53 interactions might result in multiple outcomes, such as stimulation of cellular DNA synthesis, cell cycle progression and cell cycle arrest, and prevention of program cell death.

Previous work has demonstrated that the human cytomegalovirus IE1-72 protein is able to bind to the N terminus of p107, and IE1-72 alone is sufficient for alleviation of p107-mediated cell growth suppression. However, the mechanism of this alleviation is unclear. Here, we show that IE1-72 can alleviate p107 inhibition of cyclin E/cdk2 kinase activity. We cotransfected various IE1-72 and p107 constructs into C33A cells and demonstrated that IE1-72 could activate the kinase activity of cyclin E/cdk2. Conversely, IE2-86 did not activate this activity, suggesting that the interaction between p107 and IE1-72 and the subsequent kinase activation are specific. By the use of a series of deletion and point mutants of IE1-72 and p107, we observed that a mutation of the loop region of helix-loop-helix-turn-helix in exon 3 of IE1-72 as well as a mutation of the leucine zipper-2 region in exon 4 of IE1-72 abolished binding to p107. In addition, these two IE1-72 mutants did not alleviate p107 inhibition of cyclin E/cdk2 kinase activity and also failed to alleviate p107 inhibition of the E2F-responsive promoter. Meanwhile, deletion of the N-terminal aa 1 to 175 of p107 abolished both p107 binding with IE1-72 and p107 inhibition of cyclin E/cdk2 kinase activity. This result confirms that the N-terminus aa 1 to 175 region of p107 is a common region where both IE1-72 protein and cyclin E/cdk2 bind. We propose a mechanism in which binding of IE1-72 to p107 displaces cyclin E/cdk2 from p107. Once released from p107, cyclin E/cdk2 is able to function as an active kinase.