Histopathology findings in common marmosets (Callithrix jacchus Linnaeus, 1758) with chronic weight loss associated with bile tract obstruction by infestation with Platynosomum (Loos, 1907)

Chronic weight loss in marmosets is often associated with wasting marmoset syndrome (WMS), an important disease that occurs in callitrichid colonies around the world. Even though its etiology is very difficult to determine, particular variables, such as weight loss, diarrhea and alopecia, associated or not with infestation in the pancreatic ducts with Trichospirura leptossoma (Nematoda: Thelazioidea), seem to be linked with the syndrome. This study investigated the histopathology of the lungs, duodenum, liver, gallbladder, extrahepatic bile ducts and pancreatic ducts of six common marmosets (Callithrix jacchus) suffering from severe non-diarrheic weight loss. Three individuals died naturally and the other three were euthanized. Microscopic findings showed the presence of adult flukes (Platynosomum) in the liver. These flukes, which provoke common infection in cats, were also observed inside the gallbladder as well as in the intra and extrahepatic bile ducts in common marmosets. Portal fibrosis was observed in two animals, which developed chronic fibrosing hepatopathy (biliary pattern, grade 3). The disease progresses without diarrhea and without pancreatic lesions or infestation. With the rogression, the animals presented with ascending cholangitis, cholestasis and portal fibrosis, sometimes culminating in secondary biliary cirrhosis. Therefore, this nfirmity, associated with chronic weight loss in common marmosets, could be another tiological factor linked with WMS

The role of cellular prion protein in Alzheimer’s disease

Alzheimer’s disease (AD) is the most prevalent age-related neurodegenerative disease that leads to cognitive impairment and dementia. The major defined pathological hallmark of AD is the accumulation of amyloid beta (Aβ), a neurotoxic peptide, derived from beta and gamma-secretase cleavage of the amyloid precursor protein (APP). It has been described that cellular prion protein (PrPC) plays a role in the pathogenesis of Alzheimer disease. Although, the role of PrPC is still unclear, previous studies showed contradictious results. To elucidate this issue, the main objective of the present study is to investigate the influence of a knockout of the PRNP gene in 5XFAD mice, 5xFAD mice exhibited 5 mutations related to familial Alzheimer disease. These mice show an Aβ1-42 accumulation and an increased neuronal loss during aging. To create a bi-transgenic 5xFAD mice were crossed with Prnp0/0 Zurich 1 mice (prion protein knockout mice). We subjected two transgenic mice (5xFAD and Prnp0/05xFAD) at different ages (3, 9 and 12 months of age) to a battery of task to evaluate cognitive and motoric deficits and a biochemical analysis (ELISA, western blot and immunohistochemistry) to investigate the regulation and potential involvement of downstream signaling proteins in the Aβ induced toxicity process dependent of the PrPC concentration. The study revealed that the deficits induced by Aβ mediated toxicity appeared earlier in 5xFAD mice (9 months of age) than in Prnp0/05xFAD (12 months of age). Investigating the amount of amyloid beta in 5xFAD mice we observed a PrPC dependent regulation in 9 month-old animals of Aβ1−40 but not of the toxic form Aβ1−42. We did not found in Prnp0/05xFAD mice the up-regulation of P-Fyn, Fyn or Cav-1 as we found in 5xFAD mice. This suggests an important role of PrPC in Alzheimer’s disease as a promoter of toxic effect of Aβ oligomers. Our results may suggest the loss of PrPC delays the toxicity of amyloid beta. In conclusion, our data support a role of PrPC as a mediator of Aβ toxicity in AD by promoting early onset of disease.

Whipple’s disease infection surgical treatment: presentation of a rare case and literature review

The Whipple’ Disease (W.D.) is a very rare disease with an incidence of 1 per 1.000.000 inhabitants; it is a systemic infection that may mimic a wide spectrum of clinical disorders, which may have a fatal outcome and affects mainly male 40-50 years old. The infective agent is an actinomycete, Tropheryma Whipplei (T.W.) that was isolated 100 years after first description by Wipple, and identified in macrophages of mucosa of the small intestine by biopsy which is characterized by periodic acid-Schiff-positive, products of the inner membrane of his polysaccharide bacterial cell wall. The multisystemic clinical manifestations evolve rapidly towards an organic decay characterized by weight loss, malabsorption, diarrhea, polyathralgia, opthalmoplegia, neuro-psychiatric disorders and sometimes associated to endocarditis. Early antibiotic treatment with trimethoprim and sulfometathaxazole reduces the fatal evolution of the disease. The authors present a rare experience about a female subject in which the clinical gastrointestinal signs were preceded by neuro-psychiatric disorders, and evolved into obstruction and intestinal perforation which required an emergency surgery with temporary ileostomy, recanalized only after adequate medical treatment with a full dose of antibiotic and resolution of clinical disease for the high risks of fistulae for the edema and lymphadenopathy of mucosa. The diagnosis was histologically examined by intestinal biopsy performed during surgery, which showed PAS-positive histiocytes, while PRC polymerase RNA was negative, which confirms the high sensibility of PAS positive and low specificity of RNA polymerase for T.W.

Markers for seedling and adult plant crown rot resistance in four partially resistant bread wheat sources

QTL identified for seedling and adult plant crown rot resistance in four partially resistant hexaploid wheat sources. PCR-based markers identified for use in marker-assisted selection. Crown rot, caused by Fusarium pseudograminearum, is an important disease of wheat in many wheat-growing regions globally. Complete resistance to infection by F. pseudograminearum has not been observed in a wheat host, but germplasm with partial resistance to this pathogen has been identified. The partially resistant wheat hexaploid germplasm sources 2-49, Sunco, IRN497 and CPI133817 were investigated in both seedling and adult plant field trials to identify markers associated with the resistance which could be used in marker-assisted selection programs. Thirteen different quantitative trait loci (QTL) conditioning crown rot resistance were identified in the four different sources. Some QTL were only observed in seedling trials whereas others appeared to be adult plant specific. For example while the QTL on chromosomes 1AS, 1BS, and 4BS contributed by 2-49 and on 2BS contributed by Sunco were detected in both seedling and field trials, the QTL on 1DL present in 2-49 and the QTL on 3BL in IRN497 were only detected in seedling trials. Genetic correlations between field trials of the same population were strong, as were correlations between seedling trials of the same population. Low to moderate correlations were observed between seedling and field trials. Flanking markers, most of which are less than 10 cM apart, have now been identified for each of the regions associated with crown rot resistance.

Dynamics of a large submersed plant bed in upper Chesapeake Bay

A large SAV bed in upper Chesapeake Bay has experienced several abrupt shifts over the past half-century, beginning with near-complete loss after a record-breaking flood in 1972, followed by an unexpected, rapid resurgence in the early 2000’s, then partial decline in 2011 following another major flood event. Together, these trends and events provide a unique opportunity to study a recovering SAV ecosystem from several different perspectives. First, I analyzed and synthesized existing time series datasets to make inferences about what factors prompted the recovery. Next, I analyzed existing datasets, together with field samples and a simple hydrodynamic model to investigate mechanisms of SAV bed loss and resilience to storm events. Finally, I conducted field deployments and experiments to explore how the bed affects internal physical and biogeochemical processes and what implications those effects have for the dynamics of the system. I found that modest reductions in nutrient loading, coupled with several consecutive dry years likely facilitated the SAV resurgence. Furthermore, positive feedback processes may have played a role in the sudden nature of the recovery because they could have reinforced the state of the bed before and after the abrupt shift. I also found that scour and poor water clarity associated with sediment deposition during the 2011 flood event were mechanisms of plant loss. However, interactions between the bed, water flow, and waves served as mechanisms of resilience because these processes created favorable growing conditions (i.e., clear water, low flow velocities) in the inner core of the bed. Finally, I found that that interactions between physical and biogeochemical processes led to low nutrient concentrations inside the bed relative to outside the bed, which created conditions that precluded algal growth and reinforced vascular plant dominance. This work demonstrates that positive feedbacks play a central role in SAV resilience to both chronic eutrophication as well as acute storm events. Furthermore, I show that analysis of long-term ecological monitoring data, together with field measurements and experiments, can be an effective approach for understanding the mechanisms underlying ecosystem dynamics.

Optimising plant bed performance through adaptive research with the Australian sweetpotato industry

A key driver of Australian sweetpotato productivity improvements and consumer demand has been industry adoption of disease-free planting material systems. On a farm isolated from main Australian sweetpotato areas, virus-free germplasm is annually multiplied, with subsequent 'pathogen-tested' (PT) sweetpotato roots shipped to commercial Australian sweetpotato growers. They in turn plant their PT roots into specially designated plant beds, commencing in late winter. From these beds, they cut sprouts as the basis for their commercial fields. Along with other intense agronomic practices, this system enables Australian producers to achieve worldRSQUOs highest commercial yields (per hectare) of premium sweetpotatoes. Their industry organisation, ASPG (Australian Sweetpotato Growers Inc.), has identified productivity of mother plant beds as a key driver of crop performance. Growers and scientists are currently collaborating to investigate issues such as catastrophic plant beds losses; optimisation of irrigation and nutrient addition; rapidity and uniformity of initial plant bed harvests; optimal plant bed harvest techniques; virus re-infection of plant beds; and practical longevity of plant beds. A survey of 50 sweetpotato growers in Queensland and New South Wales identified a substantial diversity in current plant bed systems, apparently influenced by growing district, scale of operation, time of planting, and machinery/labour availability. Growers identified key areas for plant bed research as: optimising the size and grading specifications of PT roots supplied for the plant beds; change in sprout density, vigour and performance through sequential cuttings of the plant bed; optimal height above ground level to cut sprouts to maximise commercial crop and plant bed performance; and use of structures and soil amendments in plant bed systems. Our ongoing multi-disciplinary research program integrates detailed agronomic experiments, grower adaptive learning sites, product quality and consumer research, to enhance industry capacity for inspired innovation and commercial, sustainable practice change.

Uterine artery Doppler in the management of early pregnancy loss: a prospective, longitudinal study

The pharmacological management of early pregnancy loss reduced substantially the need for dilation and curettage. However, prognostic markers of successful outcome were not established. Thus the major purpose of this study was to determine the sensitivity and specificity of the uterine artery pulsatility (PI) and resistance (RI) indices to detect early pregnancy loss patients requiring dilation and curettage after unsuccessful management.

A Case of Chronic Mesenteric Ischemia imitating Crohn's disease

Objectives: We present an atypical case of chronic mesenteric ischemia with weight loss as only clinical manifestation and endoscopic findings imitating Crohn´s disease. Materials and Methods: A CT Angiography of abdomen confirmed the diagnosis of mesenteric ischemia after total occlusion of celiac trunk and superior mesenteric artery. Results: The patient died due to severe sepsis, as a result of extended bowel infarction. Conclusions: The diagnosis of chronic mesenteric ischemia requires a high degree of clinical suspicion and can be life-saving if early conducted.

An assessment of Pythium spp. associated with soft rot disease of ginger (Zingiber officinale) in Queensland, Australia

In Australia, Pythium soft rot (PSR) outbreaks caused by P. myriotylum were reported in 2009 and since then this disease has remained as a major concern for the ginger industry. From 2012 to 2015, a number of Pythium spp. were isolated from ginger rhizomes and soil from farms affected by PSR disease and assessed for their pathogenicity on ginger. In this study, 11 distinct Pythium spp. were recovered from ginger farms in Queensland, Australia and species identification and confirmation were based on morphology, growth rate and ITS sequences. These Pythium spp. when tested showed different levels of aggressiveness on excised ginger rhizome. P. aphanidemartum, P. deliense, P. myriotylum, P. splendens, P. spinosum and P. ultimum were the most pathogenic when assessed in vitro on an array of plant species. However, P. myriotylum was the only pathogen, which was capable of inducing PSR symptoms on ginger at a temperature range from 20 to 35 °C. Whereas, P. aphanidermatum only attacked and induced PSR on ginger at 30 to 35 °C in pot trials. This is the first report of P. aphanidermatum inducing PSR of ginger in Australia at high temperatures. Only P. oligandrum and P. perplexum, which had been recovered only from soils and not plant tissue, appeared non-pathogenic in all assays.

Accumulation, persistence and effects of indospicine residues in camels fed Indigofera plant

Indospicine (L-2-amino-6-amidinohexanoic acid) is a natural hepatotoxin found in all parts of some Indigofera plants such as I. linnaei and I. spicata. Several studies have documented a susceptibility to this hepatotoxin in different species of animals, including cattle, sheep, dogs and rats, which are associated with mild to severe liver disease after prolonged ingestion. However, there is little published data on the effects of this hepatotoxin in camels, even though Indigofera plants are known to be palatable to camels in central Australia. The secondary poisoning of dogs after prolonged dietary exposure to residual indospicine in camel muscle has raised additional food safety concerns. In this study, a feeding experiment was conducted to investigate the in vivo accumulation, excretion, distribution and histopathological effects of dietary indospicine on camels. Six young camels (2 – 4 year old), weighing 270 − 390 kg were fed daily a roughage diet consisting of Rhodes grass hay and lucerne chaff, supplemented with Indigofera and steam flaked barley. Indigofera (I. spicata) was offered at 597 mg DM/kg body weight (bw)/day designed to deliver 337 µg indospicine/kg bw/day, and fed for a period of 32 days. Blood and muscle biopsies were collected over the period of the study. Concentrations of indospicine in the plasma and muscle biopsy samples were quantitated by validated ultra-performance liquid chromatography−tandem mass spectrometry (UPLC−MS/MS). The highest concentrations in plasma (1.01 mg/L) and muscle (2.63 mg/kg fresh weight (fw)) were found at necropsy (day 33). Other tissues were also collected at necropsy and analysis showed ubiquitous distribution of indospicine, with the highest indospicine accumulation detected in the pancreas (4.86 ± 0.56 mg/kg fw) and liver (3.60 ± 1.34 mg/kg fw); followed by the muscle, heart and kidney. Histopathological examination of liver tissue showed multiple small foci of predominantly mononuclear inflammatory cells. After cessation of Indigofera intake, indospicine present in plasma in the remaining 3 camels had a longer terminal elimination half-life (18.6 days) than muscle (15.9 days), and both demonstrated mono-exponential decreases.

Chemokines impact in Alzheimer’s disease

Alzheimer’s Disease (AD) is a neurodegenerative disorder neuropathologically characterized by the presence of extracellular senile plaques, intracellular neurofibrillary tangles and synaptic loss. Neuroinflammation has been associated with some neurodegenerative diseases, such as AD. In AD, increased Aβ production and aggregation, have a fundamental role in the activation of the inflammatory process. In turn, this could be fundamental in the early stages of this pathology, regarding the Aβ clearance and brain protection. However, chronic inflammation leads to an increase of the inflammatory mediators, such as cytokines, released by activated microglia, astrocytes, and neurons. The excessive production of these inflammatory components promotes alterations in both amyloid precursor protein (APP) expression and processing, stimulating the increase of Aβ accumulation and abnormal tau phosphorylation. This results in neurotoxic effects, irreversible damage and neuronal loss. Chronic inflammation is a feature of AD however, little is known about the effects of some chemokines on its pathogenesis. Thus, the main aim of this thesis was to study the impact of the interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) on apoptosis, APP and tau. The both studied chemokines resulted in small alterations regarding the cytotoxicity on SH-SY5Y differentiated cells, being a significant increase in apoptosis observed only for the MCP-1 at the highest concentration. For the APP processing no significant differences were obtained, although a tendency to increase at different concentrations and periods was registered for both IL-8 and MCP-1. With respect to tau and other cytoskeleton-associated proteins, it was possible to observe a tendency to increase in the phosphorylated residue (Ser396) at the higher concentrations, as well as alterations on actin and tubulin with an increase on acetylated-α tubulin. This effect can be translated by neuronal architectural and survival alterations. Therefore additional studies could contribute to a better understanding of the way that these chemokines act on AD pathogenesis.

Research into crown rot and wilt diseases of strawberries in Queensland

Plant losses due to fungal diseases in strawberry (Fragaria × ananassa Duch.) can potentially cause total loss of production. Three fungal pathogens, Fusarium oxysporum f. sp. fragariae, Colletotrichum gloeosporioides and Macrophomina phaseolina, cause similar crown rot and wilt symptoms in strawberries in Queensland. Since the withdrawal of methyl bromide in 2005, no effective chemical control of any of the three pathogens has been available. This study aims at identifying sources of plant genetic resistance that can be used in the breeding program to develop resistant cultivars for use as part of an integrated disease management plan in commercial strawberry production. Results from glasshouse pathogenicity and screening trials on the three pathogens showed that when breeding for resistance against a pathogen, resistance to other pathogens also needs to be considered, e.g., cultivar 'Festival' is resistant to F. oxysporum f. sp. fragariae, but is highly susceptible to C. gloeosporioides. The cultivars 'Earlisweet', 'Kabarla' and 'Phenomenal', two seedling clones and four DAFF breeding lines were resistant to C. gloeosporioides. Cultivar 'Suncoast Delight' showed the most promising level of resistance to M. phaseolina. These cultivars, breeding lines and seedling selections have been made available for incorporation into the crossing program to support the Queensland strawberry breeding program.

Mealybug wilt disease

Mealybug wilt disease (MWD) is a serious field disease of pineapples worldwide that was first described in Hawaii in 1910. MWD is thought to be caused by a complex involving viruses, mealybugs and ants. The viruses are transmitted by mealybugs, which in turn are tended by ants. Although a number of distinct viruses have been associated with the disease, the identity of the causal agent(s) has not been determined unequivocally. This chapter describes the disease symptopms, aetiology and management of MWD. In the last 20 years, significant advances have been achieved in identifying the causal viral agents, and gaining a better understanding of MWD. However, the interactions between the viruses, mealybugs and environmental factors are complicated, and the conditions required for the expression of MWD have only been partially elucidated at this time. The possible role of gene silencing, the identity of the additional ampelovirus(es) and badnavirus(es) that have been detected but not characterized, and the interaction between these disease-inducing factors are fertile areas for future research.

Rootstock selection, nitrogen and calcium influence postharvest disease in avocado

Field trials evaluating several parameters of growth, fruit yield and quality of 'Hass' avocado grafted to different rootstocks were established in 2004-2005 in four different growing regions of Australia. Fruit were harvested in three seasons from 2008, ripened and assessed for severity and incidence of anthracnose and stem end rot diseases. Peel samples were collected at harvest and analysed for concentrations of the cations (N, K, Ca, Mg). Rootstock significantly affected marketability of fruit (no stem end rot and less than 5% anthracnose) in 58% of the total number of trials evaluated, with better quality fruit harvested from 'Hass' grafted to Guatemalan or West Indian rootstocks such as 'A10' or 'Velvick'. Fruit quality was frequently poor from trees grafted to Mexican race rootstocks, regardless of growing location. Correlation analyses showed that fruit from rootstocks with superior fruit quality was often associated with lower skin N and higher Ca concentrations. There were significant positive correlations between anthracnose and skin N or N:Ca ratio in 75% of trials evaluated. There was a significant negative correlation between anthracnose and Ca in 42% of trials. The correlations between stem end rot and skin N (positive) or Ca (negative) were each significant in 42% of trials. Based on the results in this project, N:Ca ratios in the skin of unripe avocado fruit at harvest may provide one of the best indicators of potential postharvest disease in ripe fruit, and may have implications for fertiliser regimes.

HERITABILITY FOR RESISTANCE TO ROSETTE DISEASE IN EXOTIC VALENCIA GROUNDNUTS

Groundnut rosette disease (GRD) is the most destructive virus disease of Valencia groundnuts ( Arachis hypogaea L.) in sub-Saharan Africa. Cultural, biological and chemical control measures have received limited success due to small scale farmers’ inability to use them. Use of host plant resistance provides the most effective and economically viable management option for the resource poor farmers. This study was conducted to determine heritability for resistance to GRD in Valencia groundnuts. Six crosses; Valencia C (P1) × ICGV-SM 90704 (P2), Valencia C (P1) × ICGV-SM 96801(P2), Valencia C (P1) × ICGV-SM 99566 (P2), NuMex-M3 (P1) × ICGV-SM 90704 (P2), NuMex-M3 × ICGV-SM 96801 (P2), and NuMex-M3 (P1) × ICGV-SM 99566 (P2), were made to generate F1, F2, BC1P1 and BC1P2 populations. Data on GRD severity were collected on a 1-9 score scale. Genetic Advance as a percentage of the mean (GAM) and heritability were estimated using variance components. Phenotypic Coefficient of Variation (PCV) and Genotypic Coefficient of Variation (GCV) estimates were high (20.04-70.1%) in the six crosses, except for Valencia C × ICGV-SM 96801(18.1%) and NuMex-M3 × ICGV-SM 96801(17.1%), which exhibited moderate GCV values. Broad and narrow sense heritability estimates for GRD disease score ranged from 64.1 to 73.7% and 31 to 41.9%, respectively, in all the crosses. GAM was high in all the crosses (21-50.7%), except for Valencia C x ICGV-SM 96801 (14.67), M3 x ICGV-SM 99566 (18%) and NuMex-M3 x ICGV-SM 96801 (13.5%) crosses that exhibited moderate GAM. The study revealed the presence of variability of GRD resistance, implying that genetic improvement of these exotic materials is possible.