Sequences of the 3′ Halves of the Genomes of Barley Yellow Dwarf Virus-PAV cpA Isolates that Vary in Symptom Severity

Barley yellow dwarf virus (BYDV)-PAV isolates from USA have been separated into two distinct clusters (Chay et al. (1996) Virology 219: 57–65; Chay et al. (1996) Phytopathology 86: 370–377). Following this finding we have shown that BYDV-PAV is divided into two groups cpA and cpB based on their coat protein gene sequence, and distinct host preferences (Mastari et al. (1998) Phytopathology 88: 818–821). We have sequenced the complete 3 half of the genomes of two lethal and two mild cpA isolates and compared them with those of several known PAV cpA isolates to assess variability and locate potential determinants of severity. Open reading frames (ORFs) 3, 4, 5, 6 and the 3 untranslated regions had different percent homologies between isolates: ORF5 (92–97%), ORF3 (88–98%) 3-translational enhancer (87–100%) ORF4 (85–99%), 3 untranslated region (72–97%) and ORF6 (61–99%). In contrast to the mild isolates, the field-lethal isolates (FHv1 and FHv2) fell into the same cluster, regardless of the genomic region analysed. The isolates FHv1 and FHv2 differed from mild isolates by eight amino acid substitutions in ORFs 3 and 4, and insertions in ORF5. Four amino acid substitutions in the 17-kDa protein encoded by ORF4 caused a change in local net charge in the field-lethal isolates. Two insertions of four amino acids were identified in the C-terminal half of ORF5 of the field-lethal isolates, but were not present systematically in all lethal isolates analysed. The potential relationships of these differences in predicted amino acid sequences to disease severity are discussed.     

The tardigrade fauna of Tunisia,with an integrative description of Bryodelphax maculatus sp. nov. (Heterotardigrada: Echiniscidae)

The current knowledge of the diversity and distribution of tardigrade species in northern Africa is scarce and far from satisfactory. In this paper we review old and provide new faunistic records for various regions of Tunisia. Among the newly recorded taxa, we found a new heterotardigrade Bryodelphax maculatus sp. nov. The new species belongs to the weglarskae group, characterised by the presence of ventral plates, but differs from its congeners by a different arrangement of ventral plates and by conspicuous groups of cuticular tubercles on the ventral cuticle. The analysis of larval, juvenile and mature instars of the new species revealed, for the first time in heterotardigrades, ontogenetic variability in the development of ventral armature.

http://zoobank.org/urn:lsid:zoobank.org:pub:7EA21201-8C74-4BFD-8EAF-A131A78805F0     

Effect of 2,4-d, glutamine and BAP on embryogenic suspension culture of date palm (Phoenix dactylifera L.)

The proliferation of embryogenic suspension culture in two cultivars (Jihel and Bousthami Noir) of Phoenix dactylifera L. was tested on liquid media with or without 2,4-d and with different glutamine concentrations (3.35 × 10⁻⁴, 6.7 × 10⁻⁴ and 13.4 × 10⁻⁴ M). The liquid medium with 0.1 mg l⁻¹ 2,4-d and 6.7 × 10⁻⁴ M glutamine has clearly improved the proliferation of somatic embryos. In fact, when glutamine concentration increased from 3.35 × 10⁻⁴ to 6.7 × 10⁻⁴ M, the yield of somatic embryos increased from 14 to 56 embryos per 100 ml of culture medium for “Jihel” cultivar and 25–71 embryos per 100 ml of culture medium for “Bousthami Noir” cultivar. In contrast, increasing glutamine concentration from 6.7 × 10⁻⁴ to 13.4 × 10⁻⁴ M, the embryos yield was negligible. Based on biochemical analysis, the highest accumulation of proteins and sugars was obtained in liquid medium with 0.1 mg l⁻¹ 2,4-d and 6.7 × 10⁻⁴ M glutamine (118 and 91 mg of proteins g⁻¹ DW, respectively, for “Jihel” and “Bousthami Noir” cultivars; 194 mg of sugars g⁻¹ DW for “Jihel” cultivar and 182 mg of sugars g⁻¹ DW for “Bousthami Noir” cultivar). In addition, the supply of 0.05 mg l⁻¹ BAP on the germination medium could be useful in terms of germination percentage of somatic embryos. When BAP concentration increased from 0.05 to 0.2 mg l⁻¹, the germination percentage of somatic embryos decreased from 14.2 to 4.9%, while secondary embryogenesis increased from 26.4 to 45.2%.     

Effect of aeration on generation and emission of hydrogen sulfide in wet wells of lifting stations

The aeration of waste water in wet wells of lifting stations was studied to control the generation and emission of hydrogen suulfide in waste water. The aeration unit comprises of a compressor, aeration pipe and a ceramic fine air bubble type diffuser. The capacity of compressor was to introduce 140 m³ h^?1 air at 147 kPa pressure in waste water. The operation of aeration system was interlocked with the operation of the screws/pumps, when the screws/pumps were shut off the compressor started working. During the project the interlock between compressor and screw/pump was removed and the operation of compressor was controlled manually. Five lifting stations were selected for the study. Three were Screw Conveyor type lifting stations while the other two were equipped with centrifugal pumps. The average daily flow of waste water in the selected lifting stations varied from 371 m³ to 18 436 m³. It was experienced that the operation of the aeration system does not dissolve sufficient oxygen to control generation of H₂S, on the other hand it increases the emission of malodorous hydrogen sulfide which reduces the concentrations of sulfides in dissolved form in the waste water. Thus it increases the nuisance of malodour emission in the wet wells and affects the areas in the vicinity of lifting stations. A theoretical assessment to evaluate the efficiency of aeration system for controlling generation of Fresh H₂S and in oxidizing the H₂S already generated in the waste water in the wet wells of lifting stations is also presented.     

Bovine neonate natural killer cells are fully functional and highly responsive to interleukin-15 and to NKp46 receptor stimulation

Natural killer (NK) cells are key components of the innate immune system with their killing and cytokine producing abilities. Bovine NK cells have been characterized as NKp46⁺/CD3⁻ lymphocytes, but little is known about these cells in neonatal calves. As the newborn calf, with an insufficiently developed acquired immunity, has to employ the innate immune system, we wanted to investigate whether neonate NK cells had the same characteristics as cells from older calves. Freshly isolated neonate and calf NK cells presented the same resting CD2⁺/CD25^low/CD8^−/low phenotype. Neonates less than 8 days old had one third of the circulating NKp46⁺ cells of older calves, but the NK cells proliferated more actively in vitro in the presence of interleukin (IL)-2 or IL-15. Moreover, neonate NK cells were more cytotoxic both in an NKp46 mediated redirected lysis assay and in direct killing of a bovine cell line MDBK when cultured in the presence of IL-15. Neonate and calf NK cells cultured in the presence of IL-2 and then stimulated with IL-12 produced similar dose-dependent interferon (IFN)-γ amounts, while IL-15 cultured NK cells did not give such a response whatever the age. However, neonatal NK cells cultured in IL-15 and stimulated by IL-12 concomitantly with cross-linking of NKp46, produced 4 to 5 times more IFN-γ than calf NK cells. These data suggest that although present in lower number at birth, neonate NK cells are fully functional and are more responsive to IL-15 and activation through the NKp46 receptor than NK cells from older calves.     

Low concentrations of BAP and high rate of subcultures improve the establishment and multiplication of somatic embryos in date palm suspension cultures by limiting oxidative browning associated with high levels of total phenols and peroxidase activities

Taking into account the recalcitrance of date palm (Phoenix dactylifera L.) to tissue culture, establishment and proliferation of embryogenic suspension cultures in two date palm cultivars, namely Boufeggouss (BFG) and Bouskri (BSK) was implemented using liquid medium with different concentrations of the 6-benzylaminopurine (BAP) (0.3, 0.4, 0.5 mg/l) and various subculturing times (7 days, 15 days and 20 days). Total phenols and peroxidase activities have been determined and oxidative browning process checked in different cultures. The liquid medium with 0.3 mg/l BAP allowed cell suspension cultures to produce the greater globular embryos and the highest number of somatic embryos in comparison with the other treatment for BFG and BSK date palm cultivars. The low rate of culture transfers (every 15 or 20 days) tended to increase the phenolic contents and peroxidase activities in plant tissue leading to an enhancement of tissues/cells browning and then a decrease in the proliferation of embryogenic cells. The transfer of cultures on fresh medium every 7 days allowed a substantial reduction of tissue/cell oxidative browning, which is related to reduction of phenolic compounds and decrease in peroxidase activities with a resultant increase in the proliferation of embryogenic cells. This result suggests that oxidative browning is mainly peroxidase-based in date palm suspension cultures. Relationships between low concentrations of BAP as cytokinin, high growth of embryogenic cells, low contents of phenolics, decrease of peroxidase activities and oxidative browning process, are discussed, in order to optimize date palm multiplication through somatic embryogenesis and solve recalcitrance of many date palm cultivars to tissue culture.     

Chronic mucocutaneous candidiasis in humans with inborn errors of interleukin-17 immunity

Chronic mucocutaneous candidiasis disease (CMCD) is characterized by recurrent or persistent infections of the skin, nails, and oral and genital mucosae caused by Candida albicans and, to a lesser extent, Staphylococcus aureus, in patients with no other infectious or autoimmune manifestations. We report two genetic etiologies of CMCD: autosomal recessive deficiency in the cytokine receptor, interleukin-17 receptor A (IL-17RA), and autosomal dominant deficiency of the cytokine interleukin-17F (IL-17F). IL-17RA deficiency is complete, abolishing cellular responses to IL-17A and IL-17F homo- and heterodimers. By contrast, IL-17F deficiency is partial, with mutant IL-17F-containing homo- and heterodimers displaying impaired, but not abolished, activity. These experiments of nature indicate that human IL-17A and IL-17F are essential for mucocutaneous immunity against C. albicans, but otherwise largely redundant.