Linkage of Bacterial Protein Synthesis and Presentation of MHC Class I-Restricted Listeria monocytogenes-Derived Antigenic Peptides

The processing and MHC class I-restricted presentation of antigenic peptides derived from the p60 protein of the facultative intracellular bacterium Listeria monocytogenes is tightly linked to bacterial protein synthesis. We used non-linear regression analysis to fit a mathematical model of bacterial antigen processing to a published experimental data set showing the accumulation and decay of p60-derived antigenic peptides in L. monocytogenes-infected cells. Two alternative models equally describe the experimental data. The simulation accounting for a stable and a hypothetical rapidly degraded form of antigen predicts that the antigenic peptides p60 217–225 and p60 449–457 are derived from a putative instable form of p60 with an average intracellular half-life of approximately 3 minutes accounting for approximately 31% of all p60 molecules synthesized. The alternative model predicts that both antigenic peptides are processed from p60 degraded intracellularly with a half-life of 109 min and that antigen processing only occurs as long as bacterial protein synthesis is not inhibited. In order to decide between both models the intracellular accumulation of p60 in infected cells was studied experimentally and compared with model predictions. Inhibition of p60 degradation by the proteasome inhibitor epoxomicin revealed that during the first 3 h post infection approximately 30% of synthesized p60 molecules were degraded. This value is significantly lower than the approximately 50% degradation of p60 that would be expected in the presence of the predicted putative short-lived state of p60 and also fits precisely with the predictions of the alternative model, indicating that the tight connection of bacterial protein biosynthesis and antigen processing and presentation of L. monocyctogenes-derived antigenic peptides is not caused by the presence of a highly instable antigenic substrate

Candidiasis caused by Candida kefyr in a neonate: Case report

<p>Abstract</p> <p>Background</p> <p>Systemic <it>Candidia </it>infections are of major concern in neonates, especially in those with risk factors such as longer use of broad spectrum antibiotics. Recent studies showed that also term babies with underlying gastrointestinal or urinary tract abnormalities are much more prone to systemic <it>Candida </it>infection. We report a very rare case of candidiasis caused by <it>Candida kefyr </it>in a term neonate.</p> <p>Case Presentation</p> <p>Renal agenesis on the left side was diagnosed antenatally and anal atresia postnatally. Moreover, a vesico-ureteral-reflux (VUR) grade V was detected by cystography. The first surgical procedure, creating a protective colostoma, was uneventful. Afterwards our patient developed urosepsis caused by <it>Enterococcus faecalis </it>and was treated with piperacillin. The child improved initially, but deteriorated again. A further urine analysis revealed <it>Candida kefyr </it>in a significant number. As antibiotic resistance data about this non-<it>albicans Candida </it>species are limited, we started liposomal amphotericin B (AMB), but later changed to fluconazole after receiving the antibiogram. Candiduria persisted and abdominal imaging showed a <it>Candida </it>pyelonephritis. Since high grade reflux was prevalent we instilled AMB into the child's bladder as a therapeutic approach. While undergoing surgery (creating a neo-rectum) a recto-vesical fistula could be shown and subsequently was resected. The child recovered completely under systemic fluconazole therapy over 3 months.</p> <p>Conclusions</p> <p>Candidiasis is still of major concern in neonates with accompanying risk factors. As clinicians are confronted with an increasing number of non-<it>albicans Candida </it>species, knowledge about these pathogens and their sensitivities is of major importance.</p

Deciphering the intracellular metabolism of Listeria monocytogenes by mutant screening and modelling

Background: The human pathogen Listeria monocytogenes resides and proliferates within the cytoplasm of epithelial cells. While the virulence factors essentially contributing to this step of the infection cycle are well characterized, the set of listerial genes contributing to intracellular replication remains to be defined on a genome-wide level. Results: A comprehensive library of L. monocytogenes strain EGD knockout mutants was constructed upon insertion-duplication mutagenesis, and 1491 mutants were tested for their phenotypes in rich medium and in a Caco-2 cell culture assay. Following sequencing of the plasmid insertion site, 141 different genes required for invasion of and replication in Caco-2 cells were identified. Ten in-frame deletion mutants were constructed that confirmed the data. The genes with known functions are mainly involved in cellular processes including transport, in the intermediary metabolism of sugars, nucleotides and lipids, and in information pathways such as regulatory functions. No function could be ascribed to 18 genes, and a counterpart of eight genes is missing in the apathogenic species L. innocua. Mice infection studies revealed the in vivo requirement of IspE (Lmo0190) involved in mevalonate synthesis, and of the novel ABC transporter Lmo0135-0137 associated with cysteine transport. Based on the data of this genome-scale screening, an extreme pathway and elementary mode analysis was applied that demonstrates the critical role of glycerol and purine metabolism, of fucose utilization, and of the synthesis of glutathione, aspartate semialdehyde, serine and branched chain amino acids during intracellular replication of L. monocytogenes. Conclusion: The combination of a genetic screening and a modelling approach revealed that a series of transporters help L. monocytogenes to overcome a putative lack of nutrients within cells, and that a high metabolic flexibility contributes to the intracellular replication of this pathogen

Scaurotrechodes capensis Geginat, 2006, sp. nov.

Scaurotrechodes capensis sp. nov. Description Length 3.9 mm, body ovoid, whole body dark brown to black, appendages lighter brown to rufescent. Dorsal surfaces of head, pronotum and elytra glabrous, shiny. Head short, frontal furrows deep but not canaliculated, diverging posteriad; eyes well developed, moderately convex, not protruding; genae and temples short, tumid, length of temples approximately 1 / 3 rd of diameter of eyes. Anterior part of clypeus formed by bilobed protrusion, medial part with oval swelling followed towards base of labrum by two small laterally positioned knobs bearing each one large seta. Labrum modestly dilating distad with distal edge concave. Two supraorbital punctures with seta present, anterior one situated at the level of the centre of eyes, posterior one near posterior edge of orbital tumescence. Antennae moderately long reaching anterior seta on elytral disc; all antennomeres longer than broad. Pronotum transverse (length 0.90, width 1.19 mm, length/width ratio 0.76). Posterior angles of pronotum marked by seta but obtuse and rounded. Posterior edge of the pronotum only slightly sinuate towards base. Lateral borders of pronotum with rim between anterior corners and posterior seta that effaces thereafter. Elytra ovoid (length 2.1 mm, width 1.5 mm), shoulders rounded; scutellar stria clearly marked, no sutural stria discernable, striae 2­5 effaced; the two setiferous foveate punctures in the 3 rd interval moved towards the vestigial 3 rd stria. Setiferous punctures of series umbilicata regular with last 2 punctures moved towards apex. Anterior seta of apical group at the end of vestigial 2 nd stria, posterior setae of apical group smaller at the apical border of elytra. Microsculpture on elytra very inconspicuous, strongly transverse, length/ width ratio approximately 7: 1 (Fig. 1 E). Apterous, no vestiges of wings present. Legs short, sturdy, protibia length 0.74 mm and breadth 0.14 mm, cleaning organ well developed (Fig. 1 D). Apical spur of protarsus as long as 1 st tarsomere. Aedeagus moderately elongated, length (dorsal view) 0.82 mm, breadth 0.16 mm (Fig 1 B, C). Apical tip of median lobe slightly thickened. Internal sack without sclerotized copulatory pieces but a scale­like structure visible at 100 x magnification. Styles elongated, slender, each with 5 long apical setae. Etymology From “ capensis ”, inhabitant of the South African cape region. Remarks The loco typico of S. capensis, the Dwarsberg is part of the Hottentots Hollands Nature reserve and reaches 1523 m above see level with an annual rainfall on the Dwarsberg plateau as high as 3300 mm. The predominating vegetation type of the range is mountain finbosh with a few relics of indigenous forest which is mostly restricted to ravines. In his collection diary Dr. Endrödy­Younga further specified the habitat: 'sifting', 'in deepest S (South) valley, fern tree forest litter'. A precise altitude is not mentioned. The notes probably refer to the dense vegetation found in some of the ravines of the southeastern slope of the Dwarsberg that drain into the upper Boegoekloof valley. When the author visited the Dwarsberg range in November 2002 sifting of leaf litter in ravines of the upper Boegoekloof valley revealed the presence of a mesophilous Pachydesus species but S. capensis was not recovered. Probably recovering this interesting but elusive species might require methods that allow more effective sampling of leaf litter and superficial soil layers.Published as part of Geginat, Gernot, 2006, A new flightless trechodine genus and species from the South African Cape region (Coleoptera: Carabidae: Trechitae), pp. 63-68 in Zootaxa 1252 on pages 65-66, DOI: 10.5281/zenodo.27347

Trechosia

Key to species groups of the genus &lt;i&gt;Trechosia&lt;/i&gt; &lt;p&gt; 1 Internal sack armed with multiple spines, penultimate and antepenultimate spines enlarged, elytral microsculpture isodiametric or slightly transverse, elytral striae 1&ndash;3 not deeply impressed........................ &lt;i&gt;........................................................................................................................................ T. intermedia&lt;/i&gt; group&lt;/p&gt; &lt;p&gt;- Internal sack with single copulatory piece or copulatory piece absent, elytral microsculpture strongly transverse, elytral striae 1&ndash;3 deeply impressed........................................................................................... 2&lt;/p&gt; &lt;p&gt; 2 Posterior discal setiferous puncture on elytra in the 3rd stria........................................... &lt;i&gt;T. monticola&lt;/i&gt; group&lt;/p&gt; &lt;p&gt; - Posterior discal setiferous puncture on elytra in the 3rd interstria &lt;i&gt;....................................... T. solutilis&lt;/i&gt; group&lt;/p&gt;Published as part of &lt;i&gt;Geginat, Gernot, 2007, A new species group of the genus Trechosia from the Cape region of South Africa (Coleoptera, Carabidae, Trechinae), pp. 43-50 in Zootaxa 1469&lt;/i&gt; on page 49, DOI: &lt;a href="http://zenodo.org/record/176661"&gt;10.5281/zenodo.176661&lt;/a&gt

Taxonomic revision of the African genus Trechosiella Jeannel (Coleoptera: Carabidae: Trechinae)

Geginat, Gernot (2013): Taxonomic revision of the African genus Trechosiella Jeannel (Coleoptera: Carabidae: Trechinae). Zootaxa 3716 (3): 441-459, DOI: 10.11646/zootaxa.3716.3.

Trechosia humeralis Geginat, 2007, comb.nov.

Trechosia humeralis comb.nov. (= Plocamotrechus humeralis Jeannel, 1930, = Cothresia humeralis (Jeannel, 1930)) This species was originally described as Plocamotrechus humeralis (Jeannel 1930) but was later transferred by Jeannel (1964) into the genus Cothresia. I here repeat the characteristics of this species which fit well into the definition of the T. intermedia species group designated above. It shows much more similarity to T. intermedia than to C. curta the type species of the genus Cothresia and therefore is transferred to the genus Trechosia. The species is only known in the single female type specimen from the vicinity of Cape Town. Differential diagnosis. Size intermediate between T. intermedia and T. kogelbergensis. In contrast to T. intermedia and T. kogelbergensis apical end of the scutellar stria converging towards the elytral suture and striae 5 and 6 as well marked as the 4 th stria. Elytral microsculpture of the sutural interval slightly more transverse than in T. intermedia but much less transverse than in T. kogelbergensis. Description. Similar to T. intermedia from which it differs as follows: Length (measured from apex of elytra to anterior edge of labrum) 3.8 mm. Colour of body and appendages similar to T. intermedia but antennomeres brown, scape and bases of antennomeres 2–11 lighter reddish brown (Fig. 3 A). Pronotum: length 0.8 mm, width 1.0 mm, length/width ratio 0.8. Elytra: length 2.2 mm, width 1.6 mm, length/width ratio 1.4. Scutellar stria shorter, converging towards suture, ending well before level of anterior discal setiferous puncture. Striae 1–6 neatly impressed, well marked towards apex. Striae 1–3 effacing between base and anterior setiferous puncture, striae 4–6 not effacing towards base of elytra. Stria 7 partly effaced. Microsculpture of elytra in sutural interval slightly more transverse than in T. intermedia, slightly more transverse in 1 st (sutural) than in 2 nd interval, length/width ratio of mesh in sutural interval approximately 2: 1 (Fig. 3 B). Macropterous. Aedeagus unknown. Material examined. Holotype female: “Cape Town, Dr. Purcell” [the unique type specimen preserved in the Muséum National d'Histoire Naturelle, Paris, France (MNHN) was examined] Remarks. The precise type locality of T. humeralis is not known. Without citing a specified source Jeannel suggests that the type locality of T. humeralis is probably the forest area around Stellenbosch, 20 km east of Cape Town (Jeannel 1964). In its morphological characteristics (e.g. size, microsculpture) T. humeralis lies between T. kogelbergensis and T. intermedia. This intermediary position of T. humeralis correlates well with the type locality “Cape Town” of T. humeralis which is situated geographically between the Cedarberg 160 km north of Cape Town and the Kogelberg 40 km east of Cape Town.Published as part of Geginat, Gernot, 2007, A new species group of the genus Trechosia from the Cape region of South Africa (Coleoptera, Carabidae, Trechinae), pp. 43-50 in Zootaxa 1469 on page 48, DOI: 10.5281/zenodo.17666

Trechosia intermedia Geginat, 2007, n.sp.

Trechosia intermedia species group The T. intermedia species group is erected for three species (T. intermedia n.sp, T. kogelbergensis n.sp., and T. humeralis) which in their general external morphology are most similar to T. monticola (Péringuey). In the T. intermedia species group as well as in the T. monticola species group the posterior discal setiferous puncture is positioned in the 3 rd elytral stria. The general shape of the aedeagus is similar to other species of the genus Trechosia but the internal sack bears a series of prominent spines instead of the single large copulatory piece present in most other species of the genus. Further the elytral striae 1–3 are less impressed, the outer striae are less effaced, and also the elytral microsculpture is less transverse than among other known species of the genus. The sum of these characteristic clearly separates the T. intermedia species group from all other species of the genus Trechosia as well as from all other genera of the tribus Plocamotrechini. As all these characteristics (elytral striation, copulatory pieces of internal sack, elytral microsculpture) are known to vary largely among some members of the subfamily Trechinae I currently refrain from erecting a new genus or subgenus for these species. Instead, all three species are put into a new species group in order to indicate their suspected close relationship. All three species of the T. intermedia group are geographically restricted to the Cape region of South Africa within the limits of the Cape Floral Kingdom. They are currently only known from their type localities. However, their distribution probably is not strictly localized as all three species are macropterous and show no sign of adaptation to an endogeic life style. The type locations of T. intermedia and T. kogelbergensis suggest that these species require a high degree of humidity. Thus in their ecological requirements they probably resemble the other known species of the genus Trechosia, which all are macropterous and frequently found near open water.Published as part of Geginat, Gernot, 2007, A new species group of the genus Trechosia from the Cape region of South Africa (Coleoptera, Carabidae, Trechinae), pp. 43-50 in Zootaxa 1469 on page 44, DOI: 10.5281/zenodo.17666

Trechosia intermedia Geginat, 2007, sp. nov.

Trechosia intermedia sp. nov. Diagnosis. Small Trechosia species, well differentiated from all other species of the genus by the elytral striation pattern, the elytral microsculpture, and the internal armature of the aedeagus. Elytral striae 1–3 not deepened, striae 5–7 still well discernible, only outer striae slightly effaced towards elytral borders. Internal sack of the aedeagus armed with a series of prominent spines. Penultimate and antepenultimate spines enlarged enormously. Antepenultimate spine longer than parameres without setae. Description. Length (measured from apex of elytra to anterior edge of labrum) 4.3 mm, whole body shiny, elytra reddish brown, pronotum and head darker brown, legs yellow, antennae rufescent (Fig. 1 A). Head with large, glabrous, moderately protruding eyes, short temples (less than 1 / 3 rd of diameter of eyes); temporal tumescence weakly developed, moderately convex and only slightly protruding. Two supraorbital punctures with seta present, anterior one situated at level of centre of eyes, posterior one near posterior edge of orbital tumescence. Frons with moderately deep, not canaliculated frontal furrows which converge inwards in basal half, diverge thereafter towards anterior edge of clypeus where frontal furrows become obsolete before each ending in a large terminal bisetous fovea. Labrum oblong, much wider than long, anterior edge concave, bearing two long lateral and two short medial setae. Antennae reaching anterior seta on elytral disc; all antennomeres longer than broad, scape with 2 medially, 2 laterally and 1 dorsally projecting setae, antennomeres 2–4 with numerous setae, antennomeres 5–11 densely pubescent. Mentum transverse, mentum tooth bifid. Suture between mentum and submentum distinct and entire. Mentum posterior central recessus with two long anteriad projecting setae. Tip of ligula broadly rounded, each side with 1 long and 1 short central and 2 short lateral setae (Fig. 1 C). Penultimate palpomere of palps club-shaped, distally dilated, terminal palpomere cone-shaped in maxillary palps, spindle-shaped in labial palps, as long as penultimate palpomere in maxillary and labial palps. Penultimate palpomere of labial palps with 4 setae, two of them projecting from medial surface of palpomere. Pronotum transverse (length 0.8 mm, width 1.1 mm, length/width ratio 0.8). Lateral convexity of borders towards base without sinuosity, ending well before posterior angles. Hind angles sharply rectangular, protruding. Short carina reaching lateral border of pronotum shortly before hind angle. Posterior edge of pronotum slightly convex. Pronotum on each side with large basal impressions, small central basal impression at beginning of mid line. Elytra moderately elongated (length 2.5 mm, width 1.6 mm, length/width ratio 1.5), shoulders well developed. Scutellar stria well marked, parallel to suture, ending at level of anterior discal setiferous puncture. Elytral striae 1–4 well marked on disc, striae 1–3 effacing between anterior setiferous puncture and elytral base, striae 5–7 more effaced but still clearly discernible. Recurrent sutural stria more impressed at the apex, effacing thereafter, merging with the 5 th elytral stria. Third stria with two setiferous foveate punctures. Setiferous punctures of series umbilicata regular with last 2 punctures moved towards apex. Anterior seta of apical group at end of vestigial 2 nd stria, posterior setae of apical group smaller at apical border of elytra. Microsculpture of elytra isodiametric to moderately transverse, identical in 1 st (sutural) and 2 nd intervals, length/width ratio of mesh approximately 1: 1 to 2: 1 (Fig. 1 B). Macropterous. Legs slender, cleaning organ well developed. Apical spur of protarsus as long as 1 st tarsomere. Proximal two tarsomeres of protarsi of male medially enlarged with an anteriad projecting dent. Aedeagus length (dorsal view) 1.0 mm (Fig. 1 D). Apex of median lobe elongated, tip of median lobe thickened. Internal sack with series of well sclerotized dents, antepenultimate and penultimate dents enormously enlarged, protruding from apical orifice. Antepenultimate spine longer than styles (without apical setae). Styles broadly rounded apically, each bearing five long setae at apex. Etymology. From the Latin adjective “ intermedia ”, intermediate. Material examined. Holotype male: S.Africa, Cape-Cedarbg., jeep track, 1130 m [a.s.l.], sifted marsh shore, 32 ° 28 ’S / 19 ° 14 ’E, 7.11. 1983, E-Y: 2055, leg. Endrödy-Younga [deposited in Transvaal Museum, Pretoria, South Africa (TMSA)]. Paratypes: S.Africa, Cape-Cedarbg., jeep track, 1130 m [a.s.l.], sifted marsh shore, 32 ° 28 ’S / 19 ° 14 ’E, 7.11. 1983, E-Y: 2055, leg. Endrödy-Younga, [5 specimens in TMSA, 2 specimens in coll. Geginat]; Cape Prov.: Clanwilliam distr., Sederberg, 1500m [a.s.l.], VII 1958, leg. J.Smith [6 specimens in Musée Royal de l'Afrique Centrale, Tervuren, Belgium (MRAC), 2 specimens in coll. Geginat]. Remarks. Trechosia intermedia is only known from the Cedarberg range south-east of Clanwilliam, Western Cape Province. Despite the fact that during most of the year the climate of the Cedarberg is generally quite arid there is a permanent bog at an altitude of around 1000 m which is crossed by the road connecting the Algeria and Sanddrif campsites. This place probably is the type location of T. intermedia. My visit to this place in 2002 did not reveal any Plocamotrechini.Published as part of Geginat, Gernot, 2007, A new species group of the genus Trechosia from the Cape region of South Africa (Coleoptera, Carabidae, Trechinae), pp. 43-50 in Zootaxa 1469 on pages 44-45, DOI: 10.5281/zenodo.17666