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Myrmecotypus jasmineae Leister & Miller, 2014, sp. n.
No full textMyrmecotypus jasmineae sp. n. Figs 1 A–G, 2 A–F Type material. Holotype ♂ (MSBA 30574) and 1 ♂ paratype (MSBA 30575) from Nicaragua: Granada Dpto: Las Plazuelas (11.77082 °N – 85.96146 °W), 62m, 17 May 2012 (leg. K. B. Miller, M. P. Leister and R. Mallis). Other material examined. 1 immature ♀ (MSBA 30576) from Nicaragua: Granada Dpto: Las Plazuelas (11.77082 °N – 85.96146 °W), 62m, 17 May 2012 (leg. K. B. Miller, M. P. Leister and R. Mallis). Etymology. The name is a noun of the genitive case. The species name is for the daughter of Matthew Leister, Jasmine E. Leister. She has taught Matthew Leister to stay young at heart and to always follow his dreams. Diagnosis. Males of Myrmecotypus jasmineae can be distinguished from those of other species by the following combination of characters: (1) coxae coloration (coxae II and III translucent white, coxae I and IV black), (2) the presence of a terminal denticle on the promargin of the chelicerae, (3) the ventral spination of 3 – 2 on tibia I, and (4) the male embolus with a distinctly twisted tip (Fig. 1 B, E, G; 2 D–F). Description. Male (Holotype): Body length 3.75. Carapace length 1.95; width 1.10; carapace index 56. Cephalic width 0.75; cephalic index 68. Sternum length 0.90; width 0.60; sternum index 0.67. Abdomen length 1.70; width 1.20; abdominal index 71. Dorsal sclerite length 1.65; width 1.20. Epigastric sclerite length 0.50; width 0.75. Ventral sclerite length 0.70; width 0.50. Inframammilliary sclerite length 0.25; width 0.30. Eyes: AME 0.125; ALE 0.050; PME 0.075; PLE 0.075; AME–AME 0.075; AME–ALE 0.025; ALE–PLE 0.075; PME–PME 0.175; PME–PLE 0.075. Carapace black, granulose, elongate, oval slightly constricted at cephalic region, anterior margin truncate, sparse white setae throughout; eight eyes formed in two rows; PER very slightly recurved, posterior eyes sub-equal, small; AER slightly recurved, AME largest, nearly three times diameter of ALE, ALE small; PER wider than AER; thoracic groove absent, slight depression seen (Fig, 1 A; 2 A). Abdomen with dorsum black, round, longer than wide, widened posteriorly; dorsal sclerite nearly complete, black, granulose, covered in sparse white setae intermixed with faint feathery setae; anterior pair of abdominal setae long, thin, posterior pair of abdominal setae long, slightly thicker than anterior pair (Fig. 1 A, C; 2 A); venter brown-black, covered in white setae, faint white feathery setae seen on lateral sides below epigastric sclerite; epigastric sclerite round, brownblack; ventral sclerite rectangular, longer than wide brown-black; inframamillary sclerite round, brown-black ending posteriorly with small tubercle bearing a row of short stout black setae (Fig. 1 B; 2 D). Sternum brown-black, longer than wide, shield-shaped, covered in sparse long white setae, contiguous with intercoxal sclerites and precoxal triangles; labium brown-black, square, rounded anteriorly; endites brown-black, rectangular, longer than wide (Fig. 1 B; 2 D); chelicerae black, two retromarginal teeth and two promarginal teeth more proximally placed, distal promarginal tooth largest, prominent denticle just beyond distal tooth on promarginal side (Fig. 1 B). Coxa I black, coxae II, III translucent white with slightly darkened laterally, coxa IV black with faint lightening ventrally on distal margin (Fig 1 A–C; 2 A, D); trochanters following pattern of coxae; trochanter IV very slightly notched; proximal margin of femur I black, remainder white with two black ventro-lateral longitudinal lines, dorsal surface yellow with medial black line tapering distally, patella, tibia, and metatarsus I yellow with black pro- and retrolateral lines, tarsus I yellow; femur II white ventrally, black on prolateral surface, retrolateral surface proximally brown-black fading to white distally, black line on distal half of dorsal surface, patella, tibia, and metatarsus II yellow with black pro- and retrolateral lines, tarsi II yellow; femur III black, patella III brown black, dorsally lightened, tibia III black fading distally on dorsal surface to yellow-brown, metatarsus III ventrally black fading to yellow-brown distally, dorsally yellow-brown fading to yellow, pro- and retrolaterally brown black, tarsi III white; femur IV black, patella IV brown black, dorsally lightened, tibia IV black, metatarsus IV black fading distally to yellow-brown, tarsi IV yellowbrown (Figs 2 A, D); tibia I ventral spination 3 – 2 with long, thin spines. Pedipalp with very small pointed RTA at distal end of tibia, continuing proximally as thin sclerotized ridge; genital bulb globose, extending into thick neck, ending in distinctive, twisted embolus (Figs 1 D–G). Leg formula: assumed, IV, I, II, III, (leg II incomplete). Variation. Male paratype: Body length 3.85. Carapace length 1.95; width 1.10; carapace index 56. Cephalic width 0.85; cephalic index 77. Sternum length 0.85; width 0.55; sternum index 65. Abdomen length 1.75; width 1.15; abdominal index 66. Dorsal sclerite length 1.60; width 1.15. Epigastric sclerite length 0.55; width 0.80. Ventral sclerite length 0.75; width 0.50. Inframamillary sclerite length 0.20; width 0.35. Coloration: red-orange carapace, chelicerae and legs (Figs 2 B, E). Leg formula: IV, I, II, III. Distribution. Known only from the type locality. Remarks. A penultimate female specimen examined. Body length 4.20. Carapace length 2.05; carapace width 0.95; carapace index 46. Cephalic width 0.80; cephalic index 84. Sternum length 0.90; sternum width 0.60; sternum index 67. Abdomen length 2.00; abdomen width 1.25; abdominal index 63. Similar to male holotype in coloration (Figs 2 C, F), spination, eye arrangement, cheliceral teeth. Dorsal, epigastric, ventral and inframamillary sclerites not evident; epigynum with some sclerotization of spermathecae evident, indicating a penultimate specimen.Published as part of Leister, Matthew & Miller, Kelly, 2014, A new species of ant mimicking spider, Myrmecotypus jasmineae (Araneae: Corinnidae: Castianeirinae), from Nicaragua, pp. 495-500 in Zootaxa 3838 (4) on pages 496-498, DOI: 10.11646/zootaxa.3838.4.8, http://zenodo.org/record/23049
Role of Plastid Protein Phosphatase TAP38 in LHCII Dephosphorylation and Thylakoid Electron Flow
No full textShort-term changes in illumination elicit alterations in thylakoid protein phosphorylation and reorganization of the photosynthetic machinery. Phosphorylation of LHCII, the light-harvesting complex of photosystem II, facilitates its relocation to photosystem I and permits excitation energy redistribution between the photosystems (state transitions). The protein kinase STN7 is required for LHCII phosphorylation and state transitions in the flowering plant Arabidopsis thaliana. LHCII phosphorylation is reversible, but extensive efforts to identify the protein phosphatase(s) that dephosphorylate LHCII have been unsuccessful. Here, we show that the thylakoid-associated phosphatase TAP38 is required for LHCII dephosphorylation and for the transition from state 2 to state 1 in A. thaliana. In tap38 mutants, thylakoid electron flow is enhanced, resulting in more rapid growth under constant low-light regimes. TAP38 gene overexpression markedly decreases LHCII phosphorylation and inhibits state 1-->2 transition, thus mimicking the stn7 phenotype. Furthermore, the recombinant TAP38 protein is able, in an in vitro assay, to directly dephosphorylate LHCII. The dependence of LHCII dephosphorylation upon TAP38 dosage, together with the in vitro TAP38-mediated dephosphorylation of LHCII, suggests that TAP38 directly acts on LHCII. Although reversible phosphorylation of LHCII and state transitions are crucial for plant fitness under natural light conditions, LHCII hyperphosphorylation associated with an arrest of photosynthesis in state 2 due to inactivation of TAP38 improves photosynthetic performance and plant growth under state 2-favoring light conditions
Cytoplasmic N-Terminal Protein Acetylation Is Required for Efficient Photosynthesis in Arabidopsis
No full textThe Arabidopsis atmak3-1 mutant was identified on the basis of a decreased effective quantum yield of photosystem II. In atmak3-1, the synthesis of the plastome-encoded photosystem II core proteins D1 and CP47 is affected, resulting in a decrease in the abundance of thylakoid multiprotein complexes. DNA array-based mRNA analysis indicated that extraplastid functions also are altered. The mutation responsible was localized to AtMAK3, which encodes a homolog of the yeast protein Mak3p. In yeast, Mak3p, together with Mak10p and Mak31p, forms the N-terminal acetyltransferase complex C (NatC). The cytoplasmic AtMAK3 protein can functionally replace Mak3p, Mak10p, and Mak31p in acetylating N termini of endogenous proteins and the L-A virus Gag protein. This result, together with the finding that knockout of the Arabidopsis MAK10 homolog does not result in obvious physiological effects, indicates that AtMAK3 function does not require NatC complex formation, as it does in yeast. We suggest that N-acetylation of certain chloroplast precursor protein(s) is necessary for the efficient accumulation of the mature protein(s) in chloroplasts
Nuclear Photosynthetic Gene Expression Is Synergistically Modulated by Rates of Protein Synthesis in Chloroplasts and Mitochondria
No full textArabidopsis thaliana mutants prors1-1 and -2 were identified on the basis of a decrease in effective photosystem II quantum yield. Mutations were localized to the 5'-untranslated region of the nuclear gene PROLYL-tRNA SYNTHETASE1 (PRORS1), which acts in both plastids and mitochondria. In prors1-1 and -2, PRORS1 expression is reduced, along with protein synthesis in both organelles. PRORS1 null alleles (prors1-3 and -4) result in embryo sac and embryo development arrest. In mutants with the leaky prors1-1 and -2 alleles, transcription of nuclear genes for proteins involved in photosynthetic light reactions is downregulated, whereas genes for other chloroplast proteins are upregulated. Downregulation of nuclear photosynthetic genes is not associated with a marked increase in the level of reactive oxygen species in leaves and persists in the dark, suggesting that the transcriptional response is light and photooxidative stress independent. The mrpl11 and prpl11 mutants are impaired in the mitochondrial and plastid ribosomal L11 proteins, respectively. The prpl11 mrpl11 double mutant, but neither of the single mutants, resulted in strong downregulation of nuclear photosynthetic genes, like that seen in leaky mutants for PRORS1, implying that, when organellar translation is perturbed, signals derived from both types of organelles cooperate in the regulation of nuclear photosynthetic gene expression
The E subunit of photosystem I is not essential for linear electron flow and photoautotrophic growth in Arabidopsis thaliana
No full textPSI-E is part of the stromal side of photosystem
I (PSI). In Arabidopsis thaliana, the two nuclear genes
PsaE1 and PsaE2 code for PSI-E, and transcripts of PsaE1
are markedly more abundant than PsaE2 transcripts. Stable
null alleles of the two PsaE genes, psae1-3 and psae2-1,
were identiWed and characterised. The psae2-1 mutant
exhibited wild-type like PSI-E abundance and photosynthetic
performance, whereas in the psae1-3 mutant PSI-E
accumulation was decreased by 85%, together with an
impaired thylakoid electron Xow and plant growth rate. The
psae1-3 psae2-1 double mutant totally lacked PSI-E but
was still able to grow photoautotrophically, implying that
PSI-E is not essential for PSI accumulation and thylakoid
electron flo
SPL8, an SBP-box gene that affects pollen sac development in Arabidopsis
No full textSQUAMOSA PROMOTER BINDING PROTEIN-box genes (SBP-box genes) encode plant-specific proteins that share a highly conserved DNA binding domain, the SBP domain. Although likely to represent transcription factors, little is known about their role in development. In Arabidopsis, SBP-box genes constitute a structurally heterogeneous family of 16 members known as SPL genes. For one of these genes, SPL8, we isolated three independent transposon-tagged mutants, all of which exhibited a strong reduction in fertility. Microscopic analysis revealed that this reduced fertility is attributable primarily to abnormally developed microsporangia, which exhibit premeiotic abortion of the sporocytes. In addition to its role in microsporogenesis, the SPL8 knockout also seems to affect megasporogenesis, trichome formation on sepals, and stamen filament elongation. The SPL8 mutants described help to uncover the roles of SBP-box genes in plant development
Tracking the function of the cytochrome c6-like protein in higher plants
No full textThe contention that plastocyanin is the only mobile electron donor to photosystem I in higher plants was recently shaken by the discovery of a cytochrome c6-like protein in Arabidopsis and other flowering plants. However, the genetic and biochemical data presented in support of the idea that the cytochrome c6 homologue can replace plastocyanin have now been challenged by two complementary studies. This re-opens the debate on the real function(s) of cytochrome c in the chloroplasts of higher plants.
During the past few years, the genetic analysis of photosynthesis has identified novel photosynthetic polypeptides, as well as unexpected protein–function relationships [1] and [2]. In 2002, a major surprise was reported by two groups – the identification of a cytochrome c6 (cyt c6)-like protein in higher plants [3] and [4]. Before this, it was generally accepted that this protein had been lost during the evolution of angiosperms, and only algae and cyanobacteria were thought to use either plastocyanin or cyt c6 as electron donors to photosystem I (PSI) [5]. Using database analyses, Christopher Howe's group identified cyt c6-like sequences in the genomes and transcriptomes of several higher-plant species [4]. In parallel, Sheng Luan's group discovered the Arabidopsis cyt c6 homologue in a screen for proteins that interacted with chloroplast immunophilins [3]. From biochemical and genetic analyses, Sheng Luan and co-workers concluded that the cyt c6-like protein is targeted to the thylakoid lumen where it can replace plastocyanin in reducing PSI [3].
Two more-recent studies [6] and [7] now challenge the contention that the higher-plant cyt c6 homologue donates electrons to PSI and is capable of functionally replacing plastocyanin. In turn, the new analyses raise the question of what function(s) the cyt c6-like protein serves in higher plants
FIGURES 2A–F in A new species of ant mimicking spider, Myrmecotypus jasmineae (Araneae: Corinnidae: Castianeirinae), from Nicaragua
No full textFIGURES 2A–F. Myrmecotypus jasmineae sp. n. A, D. Holotype male, B, E. Paratype male, C, F. Female, juvenile; A–C. Dorsal view; D–F. Ventral view.Published as part of Leister, Matthew & Miller, Kelly, 2014, A new species of ant mimicking spider, Myrmecotypus jasmineae (Araneae: Corinnidae: Castianeirinae), from Nicaragua, pp. 495-500 in Zootaxa 3838 (4) on page 497, DOI: 10.11646/zootaxa.3838.4.8, http://zenodo.org/record/23049
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