A numerical taxonomic study of Actinobacillus, Pasteurella and Yersinia

A numerical taxonomic study of strains of Actinobacillus, Pasteurella and Yersinia, with some allied bacteria, showed 23 reasonably distinct groups. These fell into three major areas. Area A contained species of Actinobacillus and Pasteurella: A. suis, A. equuli, A. lignieresii, P. haemolytica biovar A, P. haemolytica biovar T, P. multocida, A. actinomycetemcomitans, 'P. bettii', 'A. seminis', P. ureae and P. aerogenes. Also included in A was a composite group of Pasteurella pneumotropica and P. gallinarum, together with unnamed groups referred to as 'BLG', 'Mair', 'Ross' and 'aer-2'. Area B contained species of Yersinia: Y. enterocolitica, Y. pseudotuberculosis, Y. pestis and a group 'ent-b' similar to Y. enterocolitica. Area C contained non-fermenting strains: Y. philomiragia, Moraxella anatipestifer and a miscellaneous group 'past-b'. There were also a small number of unnamed single strains.     

Use of autonomous audio recordings for the rapid inventory of birds in the white‐sand forests of the Peruvian Amazon

White‐sand forests are patchily distributed ecosystems covering just 5% of Amazonia that host many specialist species of birds not found elsewhere, and these forests are threatened due to their small size and human exploitation of sand for construction projects. As a result, many species of birds that are white‐sand specialists are at risk of extinction, and immediate conservation action is paramount for their survival. Our objective was to evaluate current survey methods and determine the relative effect of the size of patches of these forests on the presence or absence of white‐sand specialists. Using point counts and autonomous recorders, we surveyed avian assemblages occupying patches of white‐sand forest in the Peruvian Amazon in April 2018. Overall, we detected 126 species, including 21 white‐sand forest specialists. We detected significantly more species of birds per survey point with autonomous recorders than point counts. We also found a negative relationship between avian species richness and distance from the edge of patches of white‐sand forest, but a significant, positive relationship when only counting white‐sand specialists. Although we detected more species with autonomous recorders, point counts were more effective for detecting canopy‐dwelling passerines. Therefore, we recommend that investigators conducting surveys for rare and patchily distributed species in the tropics use a mixed‐method approach that incorporates both autonomous recorders and visual observation. Finally, our results suggest that conserving large, continuous patches of white‐sand forest may increase the likelihood of survival of species of birds that are white‐sand specialists.     

Sequence Determinants of GLUT1 Oligomerization: ANALYSIS BY HOMOLOGY-SCANNING MUTAGENESIS*

The human blood-brain barrier glucose transport protein (GLUT1) forms homodimers and homotetramers in detergent micelles and in cell membranes, where the GLUT1 oligomeric state determines GLUT1 transport behavior. GLUT1 and the neuronal glucose transporter GLUT3 do not form heterocomplexes in human embryonic kidney 293 (HEK293) cells as judged by co-immunoprecipitation assays. Using homology-scanning mutagenesis in which GLUT1 domains are substituted with equivalent GLUT3 domains and vice versa, we show that GLUT1 transmembrane helix 9 (TM9) is necessary for optimal association of GLUT1-GLUT3 chimeras with parental GLUT1 in HEK cells. GLUT1 TMs 2, 5, 8, and 11 also contribute to a less abundant heterocomplex. Cell surface GLUT1 and GLUT3 containing GLUT1 TM9 are 4-fold more catalytically active than GLUT3 and GLUT1 containing GLUT3 TM9. GLUT1 and GLUT3 display allosteric transport behavior. Size exclusion chromatography of detergent solubilized, purified GLUT1 resolves GLUT1/lipid/detergent micelles as 6- and 10-nm Stokes radius particles, which correspond to GLUT1 dimers and tetramers, respectively. Studies with GLUTs expressed in and solubilized from HEK cells show that HEK cell GLUT1 resolves as 6- and 10-nm Stokes radius particles, whereas GLUT3 resolves as a 6-nm particle. Substitution of GLUT3 TM9 with GLUT1 TM9 causes chimeric GLUT3 to resolve as 6- and 10-nm Stokes radius particles. Substitution of GLUT1 TM9 with GLUT3 TM9 causes chimeric GLUT1 to resolve as a mixture of 6- and 4-nm particles. We discuss these findings in the context of determinants of GLUT oligomeric structure and transport function.     

Plasticity of monkey triceps muscle fibers in microgravity conditions.

We examined the changes in functional properties of triceps brachii skinned fibers from monkeys flown aboard the BION 11 satellite for 14 days and after ground-based arm immobilization. The composition of myosin heavy chain (MHC) isoforms allowed the identification of pure fibers containing type I (slow) or type IIa (fast) MHC isoforms or hybrid fibers coexpressing predominantly slow (hybrid slow; HS) or fast (hybrid fast) MHC isoforms. The ratio of HS fibers to the whole slow population was higher after flight (28%) than in the control population (7%), and the number of fast fibers was increased (up to 86% in flight vs. 12% in control). Diameters and maximal tensions of slow fibers were decreased after flight. The tension-pCa curves of slow and fast fibers were modified, with a decrease in pCa threshold and an increase in steepness. The proper effect of microgravity was distinguishable from that of immobilization, which induced less marked slow-to-fast transitions (only 59% of fast fibers) and changed the tension-pCa relationships.     

Social behavior in a captive chimpanzee (Pan troglodytes) group

A group of captive chimpanzees, consisting of one adult male and three mother/infant pairs, was systematically observed over a 15-month period. Over 200 hr of data were collected, using both sequential and time sampling techniques, and compared to the available data on wild chimps. Unlike many captive groups, most behavior patterns were remarkably similar, both qualitatively and quantitatively, to that of wild chimpanzees including: play, grooming, infant sexual development, tool use, food sharing, prosocial partner preferences, and aggressive displays.     

Novel inhibition of proteoglycan synthesis and exocytosis by diethylcarbamazine in the Swarm rat chondrocyte

Pretreatment of cultured chondrosarcoma chondrocytes at 37 degrees C for 15 min with 15 mM diethylcarbamazine (DEC) followed by a 60-min pulse with [35S] sulfate in the presence of DEC resulted in an approximate 40% inhibition of synthesis and a 75% inhibition of secretion of 35S-proteoglycan. The inhibition was dose-related and was not due to a decrease in protein synthesis. Chondrocytes exposed for 75 min to 15 mM DEC, washed, incubated for 17 h in DEC-free medium, and then pulsed with [35S]sulfate showed no inhibition in the rate of synthesis of proteoglycan or in the per cent of radiolabeled proteoglycans exocytosed into the culture medium, indicating full reversibility of the inhibitory effect. When chondrocytes were incubated for 75 min with both 1 mM beta-D-xyloside and 15 mM DEC, secretion of beta-D-xyloside-bound 35S-glycosaminoglycan was inhibited by more than 70% despite an approximate 3-fold increase in intracellular 35S-macromolecules, as compared to cells exposed to beta-D-xyloside alone. Upon removal of DEC, the block in the secretion of beta-D-xyloside-bound 35S-glycosaminoglycans was reversed, although there was a 15-30-min lag in the initiation of exocytosis. Light and electron microscopic examination of chondrocytes after 75 min of incubation with 15 mM DEC revealed large vacuoles, a distended Golgi apparatus, and a distended endoplasmic reticulum which contained electron dense material. Upon removal of DEC, the vacuoles disappeared and distended organelles returned to their normal appearance between 15 and 30 min, coincident with the start of exocytosis of 35S-proteoglycan and beta-D-xyloside-bound 35S-glycosaminoglycan. These biochemical and morphological studies indicate that DEC treatment of chondrosarcoma chondrocytes alters the transport of molecules from the endoplasmic reticulum to the Golgi and the transport of molecules from the Golgi to the cell surface.     

Retrograde Traffic Out of the Yeast Vacuole to the TGN Occurs via the Prevacuolar/Endosomal Compartment

A large number of trafficking steps occur between the last compartment of the Golgi apparatus (TGN) and the vacuole of the yeast Saccharomyces cerevisiae. To date, two intracellular routes from the TGN to the vacuole have been identified. Carboxypeptidase Y (CPY) travels through a prevacuolar/endosomal compartment (PVC), and subsequently on to the vacuole, while alkaline phosphatase (ALP) bypasses this compartment to reach the same organelle. Proteins resident to the TGN achieve their localization despite a continuous flux of traffic by continually being retrieved from the distal PVC by virtue of an aromatic amino acid–containing sorting motif. In this study we report that a hybrid protein based on ALP and containing this retrieval motif reaches the PVC not by following the CPY sorting pathway, but instead by signal-dependent retrograde transport from the vacuole, an organelle previously thought of as a terminal compartment. In addition, we show that a mutation in VAC7, a gene previously identified as being required for vacuolar inheritance, blocks this trafficking step. Finally we show that Vti1p, a v-SNARE required for the delivery of both CPY and ALP to the vacuole, uses retrograde transport out of the vacuole as part of its normal cellular itinerary.