IAPs regulate the plasticity of cell migration by directly targeting Rac1 for degradation

Inhibitors of apoptosis proteins (IAPs) are a highly conserved class of multifunctional proteins. Rac1 is a well-studied Rho GTPase that controls numerous basic cellular processes. While the regulation of nucleotide binding to Rac1 is well understood, the molecular mechanisms controlling Rac1 degradation are not known. Here, we demonstrate X-linked IAP (XIAP) and cellular IAP1 (c-IAP1) directly bind to Rac1 in a nucleotide-independent manner to promote its polyubiquitination at Lys147 and proteasomal degradation. These IAPs are also required for degradation of Rac1 upon CNF1 toxin treatment or RhoGDI depletion. Consistently, downregulation of XIAP or c-IAP1 by various strategies led to an increase in Rac1 protein levels in primary and tumour cells, leading to an elongated morphology and enhanced cell migration. Further, XIAP counteracts Rac1-dependent cellular polarization in the developing zebrafish hindbrain and promotes the delamination of neurons from the normal tissue architecture. These observations unveil an evolutionarily conserved role of IAPs in controlling Rac1 stability thereby regulating the plasticity of cell migration and morphogenesis.     

Cross-Subtype Neutralization Sensitivity despite Monoclonal Antibody Resistance among Early Subtype A,C, and D Envelope Variants of Human Immunodeficiency Virus Type 1

The human immunodeficiency virus type 1 (HIV-1) variants that are transmitted to newly infected individuals are the primary targets of interventions, such as vaccines and microbicides, aimed at preventing new infections. Newly acquired subtype A, B, and C variants have been the focus of neutralization studies, although many of these viruses, particularly of subtypes A and B, represent viruses circulating more than a decade ago. In order to better represent the global diversity of transmitted HIV-1 variants, an additional 31 sexually transmitted Kenyan HIV-1 env genes, representing several recent infections with subtype A, as well as subtypes A/D, C, and D, were cloned, and their neutralization profiles were characterized. Most env variants were resistant to neutralization by the monoclonal antibodies (MAbs) b12, 4E10, 2F5, and 2G12, suggesting that targeting the epitopes of these MAbs may not be effective against variants that are spreading in areas of endemicity. However, significant cross-subtype neutralization by plasma was observed, indicating that there may be other epitopes, not yet defined by the limited available MAbs, which could be recognized more broadly.Most effective viral vaccines are thought to provide protection primarily by stimulating neutralizing antibodies (NAbs) to clear cell-free virus (25, 27). Because protection by NAbs requires recognition of common viral epitopes, the extreme genetic diversity of human immunodeficiency virus type 1 (HIV-1) presents a particular challenge to NAb-based vaccine approaches. Therefore, a critical starting point for studies of immune-mediated protection against HIV-1 is a collection of newly transmitted HIV-1 variants, particularly from areas of endemicity, such as sub-Saharan Africa, in order to determine whether vaccines are appropriately targeted to common epitopes from these relevant transmitted strains.During HIV-1 transmission, a bottleneck allows only one or a few variants to be transmitted to a newly infected individual (6, 9, 16, 29, 34, 37, 39), and the sensitivity of these early transmitted strains to antibody-mediated neutralization is therefore of particular interest. Newly transmitted HIV-1 variants have demonstrated significant heterogeneity in their neutralization phenotypes both within and between subtypes (2, 3, 6-8, 11, 13-15, 22, 30, 32, 36). Panels of sexually transmitted HIV-1 envelope variants (based on the envelope gene, env) have been characterized, including subtype B variants from North America, Trinidad, and Europe, subtype C variants from South Africa and Zambia, and subtype A variants from Kenya collected between 1994 and 1996 (2, 14, 15). Here, we characterize an additional 31 envelope variants from 14 subjects with sexually transmitted HIV-1 who were infected in Kenya, where subtypes A, C, and D circulate, between 1993 and 2005 (24, 31).The env genes were cloned from samples drawn 14 to 391 (median, 65) days postinfection from individuals enrolled in a prospective cohort of high-risk women in Mombasa, Kenya (19-21). Demographic characteristics of the subjects are summarized in Table ​Table1;1; the timing of first infection was determined by both HIV-1 serology and HIV RNA testing as described previously (12). All of the subjects were presumably infected by male-to-female transmission and displayed a range of plasma viral loads at the time of env gene cloning (Table ​(Table1).1). For most individuals, full-length env genes were cloned from uncultured peripheral blood mononuclear cell (PBMC) DNA, though for two individuals, clones were obtained from DNA following short-term coculture with donor PBMCs (Table ​(Table1).1). env genes were cloned by single-copy nested PCR with primers and PCR conditions as described previously (4, 17). We tested env genes for their ability to mediate infection by transfecting env plasmid DNA into 293T cells along with an env-deficient HIV-1 subtype A proviral plasmid, Q23Δenv, to make pseudoviral particles (17). More than 80 env clones were obtained from 16 subjects; less than one-half were functional on the basis of the infectivity of pseudoviral particles in a single-round infection of TZM-bl cells (AIDS Research and Reference Reagent Program, National Institutes of Health), as observed previously for env genes cloned from proviral sequences (17); a lower fraction of functional env genes have been reported from plasma (18). We focused on the proviral sequences here because they presumably best represent the sequence closest to that of the transmitted strains. The 31 functional env variants are described in Table ​Table11.

TABLE 1.

Demographic characteristics, diversities, gp120 variable-region lengths, numbers of PNGS, and accession numbers of cloned env variants

Thermophilic biohydrogen production by an anaerobic heat treated-hot spring culture

Batch experiments were conducted to investigate the thermophilic biohydrogen production using an enrichment culture from a Turkish hot spring. Following the enrichment, the culture was heat treated at 100 °C for 10 min to select for spore-forming bacteria. H₂ production was accompanied by production of acetate, butyrate, lactate and ethanol. H₂ production was associated by acetate–butyrate type fermentation while accumulation of lactate and ethanol negatively affected the H₂ yield. H₂ production was highest in the temperature range from 49.6 to 54.8 °C and optimum values for initial pH and concentrations of iron, yeast extract and glucose were 6.5, 40 mg/l, 4–13.5 g/l, respectively. PCR–DGGE profiling showed that the heat treated culture consisted of species closely affiliated to genus Thermoanaerobacterium.     

Anatomy,trichome morphology and palynology of Salvia chrysophylla Stapf (Lamiaceae)

The anatomy, palynology, morphology and distribution of the trichomes on the aerial parts of Salvia chrysophylla Stapf, an endemic species in Turkey, were studied in order to understand the usefulness of these characteristics for systematic purposes. Some anatomical characters such as (1–)2–24-rowed pith rays in roots, dorsiventral leaves, obviously larger upper epidermal cells, and two to three large vascular bundles in the center and two to four small subsidiary bundles in the wings of petiole provide information of taxonomical significance. Three main types of trichomes were observed on the stem, inflorescence axis, leaf and calyx surfaces of S. chrysophylla. They are peltate, capitate glandular and non-glandular. Capitate glandular and non-glandular trichomes were further subdivided into several kinds. Glandular trichomes are present in abundance on the inflorescence axis and calyx, but non-glandular ones were mainly situated on the leaf and stem. Scanning Electron Microscopy (SEM) studies on the pollen grains have revealed that they are oblate-spheroidal and their exine ornamentation is bireticulate-perforate.     

Central angiotensin II increases biosynthesis of tyrosine hydroxylase in the rat adrenal medulla

Angiotensin II acting centrally contributes to the regulation of blood pressure and water intake and stimulates the release of catecholamines from the adrenal medulla. We hypothesized that the central angiotensin II is one mediator of biosynthesis of catecholamines in the adrenal medulla. Rats were administered i.c.v. angiotensin II or saline, and TH mRNA and protein levels in adrenal medulla were measured 1 or 3 h later. Angiotensin II did not change TH mRNA or protein 1 h later. However, by 3 h, angiotensin II increased TH mRNA and protein levels. Centrally administered angiotensin II elevates TH mRNA expression and protein levels in the adrenal medulla. In conclusion, one component of central angiotensin II elevation of blood pressure may be the result of increased catecholamine synthesis in the adrenal gland and elevated TH synthesis represents one underlying mechanism.     

The effects of ketorolac and morphine on articular cartilage and synovium in the rabbit knee joint

Analgesics are commonly injected intra-articularly for analgesia after arthroscopic surgery, especially of knee joints. The aim of this study was to research the effects of ketorolac and morphine on articular cartilage and synovial membrane. This study used rabbit right and left hind knee joints. The treatments, saline, morphine, or ketorolac, were administered intra-articularly 24 h after injection, and 5 joints from animals in each drug group were chosen randomly to form Group I and subgroups of Group I. The same procedures were applied after 48 h and 10 days of injection to form Groups II and III, respectively, and subgroups of these groups. Knee joints were excised and a blinded observer evaluated the histopathology according to inflammation of the articular cartilage, inflammatory cell infiltration, hypertrophy, and hyperplasia of the synovial membrane. No histopathological changes were found in the control groups. In the ketorolac and morphine groups, there were varying degrees of synovial membrane inflammatory cell infiltration and minimal, mild, or moderate synovial membrane cell hyperplasia or hypertrophy. Except for the ketorolac group at 24 h, both ketorolac and morphine groups showed more histopathological changes than controls (p < 0.05). Morphine and ketorolac both cause mild histopathological changes in rabbit knee joints, morphine causing more than ketorolac, but both of the drugs can be used intra-articularly with safety.     

Strongyloidiasis associated with amebiasis and giardiaisis in an immunocompetent boy presented with acute abdomen

Strongyloides stercoralis (SS) is an intestinal nematode that is mainly endemic in tropical and subtropical regions and sporadic in temperate zones. SS infection frequently occurs in people who have hematologic malignancies, HIV infection and in individuals undergoing immunosuppressive therapy. In this study, we report a 12- year-old immunocompetent boy who was admitted to our hospital with acute abdomen. Laboratory evaluation showed strongyloidiasis, amebiasis and giardiasis. Clinical and laboratory findings immediately improved with albendazole therapy. Therefore, when diarrhea with signs of acute abdomen is observed, stool examinations should be done for enteroparasitosis. This approach will prevent misdiagnosis as acute abdomen. Complete clinical improvement is possible by medical therapy without surgical intervention.     

Genetic diversity and spoilage potentials among Pseudomonas spp. isolated from fluid milk products and dairy processing plants

Degradation of milk components through various enzymatic activities associated with the contamination of dairy products by Pseudomonas spp. can reduce the shelf life of processed milk. Reliable methods for differentiating among Pseudomonas spp. strains are necessary to identify and eliminate specific sources of bacterial contamination from dairy processing systems. To that end, we assessed the genetic diversity and dairy product spoilage potentials among a total of 338 Pseudomonas spp. isolates from raw and pasteurized milk and from environmental samples collected from four dairy processing plants. The majority of isolates were identified as P. fluorescens and P. putida by API 20 NE. A total of 42 different ribotype patterns were identified among a subset of 81 isolates. The presence of many different ribotypes within this collection indicates high genetic diversity among the isolates and suggests multiple origins of contamination within the processing plant and in dairy products. The extracellular enzyme activity patterns among Pseudomonas isolates appeared to be associated with ribotypes. Isolates with the same ribotype frequently had the same extracellular protease, lecithinase, and lipase activities. For example, isolates grouped in ribotype 55-S-6 had the highest extracellular protease activity, while those in ribotypes 50-S-8 and 72-S-3 had the highest extracellular lipase activities. We conclude that ribotyping provides a reliable method for differentiating Pseudomonas strains with dairy food spoilage potential.