Silencing of Mammalian Sar1 Isoforms Reveals COPII‐Independent Protein Sorting and Transport

The Sar1 GTPase coordinates the assembly of coat protein complex‐II (COPII) at specific sites of the endoplasmic reticulum (ER). COPII is required for ER‐to‐Golgi transport, as it provides a structural and functional framework to ship out protein cargoes produced in the ER. To investigate the requirement of COPII‐mediated transport in mammalian cells, we used small interfering RNA (siRNA)‐mediated depletion of Sar1A and Sar1B. We report that depletion of these two mammalian forms of Sar1 disrupts COPII assembly and the cells fail to organize transitional elements that coordinate classical ER‐to‐Golgi protein transfer. Under these conditions, minimal Golgi stacks are seen in proximity to juxtanuclear ER membranes that contain elements of the intermediate compartment, and from which these stacks coordinate biosynthetic transport of protein cargo, such as the vesicular stomatitis virus G protein and albumin. Here, transport of procollagen‐I is inhibited. These data provide proof‐of‐principle for the contribution of alternative mechanisms that support biosynthetic trafficking in mammalian cells, providing evidence of a functional boundary associated with a bypass of COPII .     

Secretory traffic triggers the formation of tubular continuities across Golgi sub-compartments

The organization of secretory traffic remains unclear, mainly because of the complex structure and dynamics of the secretory pathway. We have thus studied a simplified system, a single synchronized traffic wave crossing an individual Golgi stack, using electron tomography. Endoplasmic-reticulum-to-Golgi carriers join the stack by fusing with cis cisternae and induce the formation of intercisternal tubules, through which they redistribute their contents throughout the stack. These tubules seem to be pervious to Golgi enzymes, whereas Golgi vesicles are depleted of both enzymes and cargo. Cargo then traverses the stack without leaving the cisternal lumen. When cargo exits the stack, intercisternal connections disappear. These findings provide a new view of secretory traffic that includes dynamic intercompartment continuities as key players.     

Antigenic analysis of canine parvovirus strains isolated in Italy

Eighty-two canine parvovirus type 2 strains isolated in Italy from pups with severe enteritis were characterizated using four monoclonal antibodies. Sixty-eight isolates resulted CPV-2a, whereas the other fourteen were a CPV-2b variant. The diffusion of CPV-2 variants in the Italian dog population is quite similar to that reported in the United Kingdom and Australia (CPV-2a more prevalent) and different from the epidemiological conditions of the USA and other countries where CPV-2b is more widespread.     

Detection of Brucella canis in a dog in Italy

Brucella spp. is a worldwide zoonotic pathogen. Infection by Brucella canis in dogs is endemic in the Southern USA and in Central and South America, but it appears sporadically in other parts of the world, including Europe. Tissue samples from a dog with chronic prostatitis, discospondylitis and locomotor problems were subjected to clinical and laboratory examinations. B. canis was detected by PCR in biological fluids and tissues of the animal, while antibodies to B. canis were found in the serum, providing additional strong evidence for the circulation of B. canis in Italy.     

Morphological, histochemical and immunohistochemical study of the gill epithelium in the abyssal teleost fish Coelorhynchus coelorhynchus

Histochemical and immunohistochemical study was carried out on nitrinergic innervation and neuroendocrine system in the gill epithelium of the abyssal fish Coelorhynchus coelorhynchus. The results showed that nNOS-positive nerve fibers, originating from the branchial arch were present in the subepithelial tissue of branchial primary filament. nNOS-positive neuroendocrine cells were also present in the primary filaments and secondary lamellae. Numerous mucous cells in the gill epithelium were AB/PAS-positive, while sialic acid was absent as confirmed by neuraminidase reaction and WGA lectin histochemistry. The mucus compounds in abyssal teleost fish are different from those found in pelagic species, being related to their living conditions. In abyssal species, greater numbers of chloride and neuroendocrine cells are involved in the movement of water and electrolytes. Neuroendocrine cells possess oxygen receptors which mediate the cardiovascular and ventilatory response to oxygen deficiency, as reported in teleost species. Besides, NO contributes through nervous stimulation to the regulation of vascular tone and blood circulation in the gill.     

Nigrostriatal dopaminergic deficits and hypokinesia caused by inactivation of the familial Parkinsonism-linked gene DJ-1

The manifestations of Parkinson's disease are caused by reduced dopaminergic innervation of the striatum. Loss-of-function mutations in the DJ-1 gene cause early-onset familial parkinsonism. To investigate a possible role for DJ-1 in the dopaminergic system, we generated a mouse model bearing a germline disruption of DJ-1. Although DJ-1(-/-) mice had normal numbers of dopaminergic neurons in the substantia nigra, evoked dopamine overflow in the striatum was markedly reduced, primarily as a result of increased reuptake. Nigral neurons lacking DJ-1 were less sensitive to the inhibitory effects of D2 autoreceptor stimulation. Corticostriatal long-term potentiation was normal in medium spiny neurons of DJ-1(-/-) mice, but long-term depression (LTD) was absent. The LTD deficit was reversed by treatment with D2 but not D1 receptor agonists. Furthermore, DJ-1(-/-) mice displayed hypoactivity in the open field. Collectively, our findings suggest an essential role for DJ-1 in dopaminergic physiology and D2 receptor-mediated functions.     

Epizootic abortion related to infections by Chlamydophila abortus and Chlamydophila pecorum in water buffalo (Bubalus bubalis)

Water buffalo (Bubalus bubalis) are affected by high rates of embryonic mortality and abortion related to infectious diseases and non-infectious factors. A number of viral and bacterial infections have been associated with reproductive failure, but there is limited information on the role of chlamydial infections.

In order to investigate the presence and the role of Chlamydiaceae in water buffalo a retrospective study was performed in a herd with a history of reproductive failure. During an 11-month period, the pregnant heifers suffered an abortion rate of 36.8% between the 3rd and 7th month of pregnancy. Antibodies to Chlamydiaceae were detected in 57% of the aborted cows, and in 0% of the overtly healthy cows used as control. By a nested-PCR assay, three of 14 vaginal swabs from aborted animals tested positive for Chlamydophila agents and, additionally, three out of seven aborted fetuses tested positive for Chlamydophila spp., with two being co-infections by Cp. abortus and Cp. pecorum and one being characterised as Cp. abortus. Sequence analysis of the amplicons confirmed the results of the nested-PCR. The presence of anti-Chlamydiaceae antibodies in more than half of the aborting animals (P < 0.002) and the detection of Chlamydophila agents in several fetal organs and in the vaginal swabs are consistent with the history of abortions observed in the herd and suggest an abortifacient role by Chlamydophila spp. in water buffalo (B. Bubalis) herds.     

Home range of greater and lesser rhea in Argentina : relevance to conservation

In this work we report results of radiotracking studies on the movements and home range sizes of two near-threatened species, the greater rhea (Rhea americana) and the lesser rhea (Pterocnemia pennata pennata) in relation to different land use regimes. We radiomonitored greater and lesser rheas for 3 years in their respective habitats: the Pampas and the Patagonia regions. We chose two study areas in each habitat with similar agricultural activities and different hunting control. We did not find significant differences in movements and home range size between study areas of each species. This suggests that disturbance caused by human presence in the areas did not affect rhea spacing behaviors. Moreover, lesser rheas showed larger home range and movements than greater rheas, showing that the home range size is not an immutable property of body mass, and that abundance and distribution of food appears to be the main factor that influences the movements and home range size of these birds.     

Winning and losing: causes for variability in outcome of fights in male Magellanic penguins (Spheniscus magellanicus)

Game theory models predict that fighting ability should be moreimportant in contest outcome when the payoffs of winning arehigh for both contestants, and ownership should be more importantwhen payoffs are low. Male Magellanic penguins (Spheniscusmagellanicus) provide an opportunity to test these predictionsin a natural setting because payoffs of winning are higher for penguins fighting before egg laying and lower for penguinsfighting after egg laying, allowing the prediction of differencesin who should win and lose. We watched an area of approximately2000 Magellanic penguin nests from 1992 to 1996 at Punta Tombobreeding colony, Argentina; we quantified fighting behavior,banded contestants, measured their body size (here used as anindex of fighting ability), determined ownership status whenpossible, and monitored their reproductive success. We determinedthat male Magellanic penguins fought for nests and mates. Astheory predicts, before egg laying, body size difference wasmore important than ownership as a predictor of contest outcome and fight duration. After egg laying, owners won fights, andsize did not predict who won or how long they fought. Our comparisonsof nest ownership, nest quality, and chicks fledged by winnersand losers suggested that our predictions on the change inbenefits of winning before and after egg laying were correct.We conclude that game theory models are useful in predictingwho won or lost fights in male Magellanic penguins and thatultimate benefits of winning fights are related to fitness.