Effect of Arginine-deficient Media on the Herpes-Type Virus Associated with Cultured Burkitt Tumor Cells

After incubation at 37 C for 2 or more days, Basal Medium Eagle (BME) supplemented with 25% fetal calf serum (FCS) was not able to support adequate growth of EB3 and other lines of Burkitt tumor cells. The medium did, however, increase, by a factor of about 10, the number of cells synthesizing herpes-type virus with which the cultures were persistently infected. Not every lot of FCS produced these effects, nor were these effects seen when BME and FCS were incubated separately for 7 days before the medium was completed. At 37 C, appropriate lots of FCS interacted with several of the amino acids present in BME; this interaction resulted in an inhibition of cellular growth, whereas interaction with arginine yielded the virus-enhancing effect. Arginine-free BME, supplemented with 25% FCS and used without prior incubation, prevented cellular replication and promoted viral infection to a similar extent as did preincubated complete medium. Replenishment of arginine reduced, but did not regularly abolish, the virus-enhancing activity of preincubated media. RPMI-1629 medium was less affected by preincubation with FCS because it contained twice the amount of arginine that BME contained. The FCS factors which act upon arginine and other amino acids are not dialyzable and are partially resistant to heating at 56 or 60 C for 30 to 60 min. Calf and horse sera appear to be devoid of these activities. The nature of these interactions, as well as the mechanism by which arginine deficiency enhanced the viral infection, remains to be ascertained.     

Cosmopolites sordidus (Germar) susceptibility to indigenous Cameroonian Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) isolates

Management of the banana root borer (BRB), Cosmopolites sordidus (Germar; Coleoptera: Curculionidae), remains a challenge in banana and plantain production worldwide. Synthetic pesticides remain the most widely used solution while mycoinsecticides are increasingly being recommended. In this study, we selected indigenous isolates of Beauveria bassiana and Metarhizium anisopliae collected from plantain fields in Cameroon, and tested them in the laboratory for their viability, pathogenicity and virulence against all C. sordidus life stages. Of 13 isolates initially screened for spore germination and pathogenicity to adult weevils in conidial suspension of 3.2 × 10⁸ conidia/ml, eight isolates with high to moderate germination and highest weevil mortality were selected for dose–response bioassays with four concentrations per isolate: 3.2 × 10², 3.2 × 10⁴, 3.2 × 10⁶ and 3.2 × 10⁸ conidia/ml. The virulent isolates from adult bioassays were tested with eggs, larva and pupae in conidial suspension of 3.2 × 10⁸ conidia/ml. Isolates performance depended on insect life stage with significantly high pathogenicity and virulence against larval, pupa and adult stages. The Beauveria isolate BIITAC6.2.2 caused the highest mortality rates followed by MIITAC1.1.5. Lethal times and lethal concentrations were relatively low for the three M. anisopliae isolates and three B. bassiana isolates which were the best isolates in almost all insect life stages. Apart from being effective in multiple life stages, these isolates were transmitted horizontally from one stage to another when eggs and pupae were treated. The implication of these findings for integrated management of the BRB, and potential biopesticides development and commercialization are discussed.     

Risk Denial and Socio-Economic Factors Related to High HIV Transmission in a Fishing Community in Rakai,Uganda: A Qualitative Study

Background

In Kasensero fishing community, home of the first recorded case of HIV in Uganda, HIV transmission is still very high with an incidence of 4.3 and 3.1 per 100 person-years in women and men, respectively, and an HIV prevalence of 44%, reaching up to 74% among female sex workers. We explored drivers for the high HIV transmission at Kasensero from the perspective of fishermen and other community members to inform future policy and preventive interventions.

Methods

20 in-depth interviews including both HIV positive and HIV negative respondents, and 12 focus-group discussions involving a total of 92 respondents from the Kasensero fishing community were conducted during April-September 2014. Content analysis was performed to identify recurrent themes.

Results

The socio-economic risk factors for high HIV transmission in Kasensero fishing community cited were multiple and cross-cutting and categorized into the following themes: power of money, risk denial, environmental triggers and a predisposing lifestyle and alcoholism and drug abuse. Others were: peer pressure, poor housing and the search for financial support for both the men and women which made them vulnerable to HIV exposure and or risk behavior.

Conclusions

There is a need for context specific combination prevention interventions in Kasensero that includes the fisher folk and other influential community leaders. Such groups could be empowered with the knowledge and social mobilization skills to fight the negative and risky behaviors, perceptions, beliefs, misconceptions and submission attitudes to fate that exposes the community to high HIV transmission. There is also need for government/partners to ensure effective policy implementation, life jackets for all fishermen, improve the poor housing at the community so as to reduce overcrowding and other housing related predispositions to high HIV rates at the community. Work place AIDS-competence teams have been successfully used to address high HIV transmission in similar settings.     

Domestic dog origin of canine distemper virus in free-ranging wolves in Portugal as revealed by hemagglutinin gene characterization

Serologic evidence for canine distemper virus (CDV) has been described in grey wolves but, to our knowledge, virus strains circulating in wolves have not been characterized genetically. The emergence of CDV in several non-dog hosts has been associated with amino acid substitutions at sites 530 and 549 of the hemagglutinin (H) protein. We sequenced the H gene of wild-type canine distemper virus obtained from two free-ranging Iberian wolves (Canis lupus signatus) and from one domestic dog (Canis familiaris). More differences were found between the two wolf sequences than between one of the wolves (wolf 75) and the dog. The latter two had a very high nucleotide similarity resulting in identical H gene amino acid sequences. Possible explanations include geographic and especially temporal proximity of the CDV obtained from wolf 75 and the domestic dog, taken in 2007-2008, as opposed to that from wolf 3 taken more distantly in 1998. Analysis of the deduced amino acids of the viral hemagglutinin revealed a glycine (G) and a tyrosine (Y) at amino acid positions 530 and 549, respectively, of the partial signaling lymphocytic activation molecule (SLAM)-receptor binding region which is typically found in viral strains obtained from domestic dogs. This suggests that the CDV found in these wolves resulted from transmission events from local domestic dogs rather than from wildlife species.     

Endogenous Hepatitis C Virus Homolog Fragments in European Rabbit and Hare Genomes Replicate in Cell Culture

Endogenous retroviruses, non-retroviral RNA viruses and DNA viruses have been found in the mammalian genomes. The origin of Hepatitis C virus (HCV), the major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma in humans, remains unclear since its discovery. Here we show that fragments homologous to HCV structural and non-structural (NS) proteins present in the European rabbit (Oryctolagus cuniculus) and hare (Lepus europaeus) genomes replicate in bovine cell cultures. The HCV genomic homolog fragments were demonstrated by RT-PCR, PCR, mass spectrometry, and replication in bovine cell cultures by immunofluorescence assay (IFA) and immunogold electron microscopy (IEM) using specific MAbs for HCV NS3, NS4A, and NS5 proteins. These findings may lead to novel research approaches on the HCV origin, genesis, evolution and diversity.     

The Melanosome: An Ideal Model to Study Cellular Differentiation

Melanosomes provide an intriguing model for study at many levels. In part this is due to their unique structure and function, but also in part to their involvement in pigmentary diseases and as a model to study basic cellular mechanisms of organelle biogenesis. Recent studies have elucidated the full proteome of the melanosome and the metabolic and molecular lesions involved in a number of pigmentary diseases have been resolved. This paper summarizes recent advances in the field in these areas.     

Anx7 is required for nutritional control of gene expression in mouse pancreatic islets of Langerhans

BACKGROUND: Gene expression in islets of Langerhans is profoundly sensitive to glucose and other nutrients. Islets of Langerhans in the Anx7(+/-) knockout mouse exhibit a profound reduction in ITPR3 protein expression, defective intracellular calcium signaling, and defective insulin secretion. Additional data presented here also show that mRNA for ITPR3 is virtually undetectable in isolated Anx7(+/-) islets. IP3Receptor type 3 (ITPR3) expression in islets of Langerhans is closely regulated by secretory stimuli, and it has been suggested that the level of the ITPR3 expression controls the ability of the islets to respond to nutritional signals. We report that although control islets respond to glucose in vitro by a transient increment in ITPR3 mRNA, the islets from the Anx7(+/-) mouse remain low. We therefore hypothesized that the Anx7/IP3 Receptor(3)/Ca(2+) signaling pathway plays a role in beta cell responses to glucose, and that in the absence of the Anx7/ITPR3 signaling system, the islets would be unable to discriminate between fed or fasted states in vivo. MATERIALS AND METHODS: To test this hypothesis, we subjected Anx7(+/-) and control mice to either food and water ad libidum or to an overnight fast with access to water only. We then isolated the respective islets and compared nutrient-dependent changes in global gene expression under the four conditions using genome-based microarray technology. RESULTS: Anx7 protein expression in these islets is only about 50% of control levels in normal littermate controls, and IPTR3 message and protein are virtually zero. cDNA microarray analyses show that in control animals gene expression is significantly affected by the fasting state. Many of the affected genes have historical relevance to development and differentiation of islets. These include preproglucagon, APOJ, cadherin2, phosphoglucoisomerase, oncostatin M, PAX6, HGF, and cytokeratin 18. However, there are also many other nutritionally sensitive genes in control islets that are principally associated with cell division and DNA repair. The latter genes have not specifically been associated with islet physiology in the past. By contrast, Anx7(+/-) mouse islets exhibit a greatly reduced ability to discriminate genomically between fed and fasted states for all classes of identified genes. Many of the validated genes are specific to islets in comparison to liver tissue examined. Real-time quantitative RT-PCR analysis of islets from Anx7 heterozygous mice and littermate controls revealed remarkable down-regulation in PTEN, Glut-2, PDX-1, IGF-1, and Neuro D1 expression, but not in liver. CONCLUSIONS: We conclude that reduced gene dosage in the Anx7(+/-) islet, with concomitant loss of ITPR3 expression and consequent defects in Ca(2+) signaling, may substantially contribute to the mechanism of the loss of genomic discrimination, in vivo, between the fed and fasted states. We believe that the requirement for complete Anx7 gene dosage and IPTR3 expression in islets of Langerhans will prove to be of fundamental importance for understanding the mechanism of nutritional sensing in health and disease.