Emerging therapeutic agents for transmissible spongiform encephalopathies: a review

Transmissible spongiform encephalopathies (TSEs) are a group of fatal neurodegenerative disorders associated with misfolding of prion protein, from PrPC to PrPSc. Different types of experimental studies have resulted in a better understanding of the pathogenesis of the prion diseases. Genetic and molecular properties of PrP isoforms have been explained but the conformational conversion of the PrPC isoform to the PrPSc isoform has not yet been entirely elucidated. However, a number of possible therapeutic agents have been tried and some have proven to be effective against TSEs but most have limitations in terms of toxicity and pharmacokinetics. Congo red (CR), anthracyclines, and polyanionic dextran sulfate have limited ability to cross the blood-brain barrier and may be toxic. The efficacy of polyene antibiotics seems to be restricted to certain scrapie strains. Tetrapyrroles and tetracyclines with low toxicities and favorable pharmacokinetics could be useful in preventing PrPSc accumulation. Compounds like branched polyamines, Cp-60, analogs of CR, quinacrine and chlorpromazine, beta-sheet breaker peptides and inhibitory peptides, active immunization using recombinant PrP and passive immunization with anti-PrP antibodies, have potential use as therapeutic agents but would need further research and clinical trials.     

Identification of host plant resistance to pepper leaf curl virus in chilli (Capsicum species)

Three hundred and seven genotypes belonging to four cultivated and one wild species of Capsicum were screened against pepper leaf curl virus (PepLCV) causing devastating leaf curl disease of chilli (Capsicum annuum). Initial screening was done under field conditions based on coefficient of infection (CI), disease reaction to each genotype was assigned. Subsequently, selfed progenies of eight symptom-less and highly resistant lines were challenged by viruliferous white fly under glasshouse conditions, out of which only three genotypes, viz. GKC-29, BS-35 and EC-497636 showed no symptom. Using scion and root stalk of susceptible genotype (Pusa Jwala), these three putative symptom-less genotypes were further challenged by grafting and alternate grafting. The resistant reactions of GKC-29, BS-35, EC-497636 were confirmed because even after 50 days of successful grafting/alternate grafting, no viral symptom appeared on all the grafted plants of these genotypes. When subjected to PCR amplification with degenerate primers deigned to detect gemnivirus like PepLCV, the three symptom-less genotypes did not show any amplification, suggesting that the resistant reaction in three identified symptom-less resistant sources was because of the absence of viral genome and they are not symptom-less carrier.     

Characteristics of citrus fruits in relation to granulation

A study was conducted in different citrus cultivars to observe the incidence and degree of granulation, and to measure polyphenol oxidase (PPO) activity and phenolic content pattern in relation to granulation. Standard procedures were followed to observe the incidence and degree of granulation, phenolic content pattern, PPO activity and pheno-physicochemical fruit characteristics of citrus fruits. Across all citrus cultivars studied, 25% of the fruit were affected by granulation to the degree of about 10%. In general, granulated fruit were larger in size than normal fruit, and were inferior in quality characteristics. Among different citrus cultivars, ‘Kaula’ mandarin had highest incidence of granulation (62.5%), followed by ‘Mosambi’ sweet orange (43.6%) and the least in ‘Kagzi’ lime (12.2%). Phenolic content and polyphenol oxidase activity also varied widely among different citrus types, and were significantly higher in normal fruit than granulated fruit. Thus, it appears from the study that PPO plays some role in the occurrence of granulation in citrus.     

Haematological and biochemical studies in broiler chicks fed ochratoxin and inoculated with inclusion body hepatitis virus,singly and in concurrence

Day-old broiler chicks, which had been shown to be negative for maternal antibodies against inclusion body hepatitis (IBH) virus and for viral antigen in cloacal swabs, were divided into four groups of 20 chicks each. One group was fed ochratoxin-A at 0.5 ppm from 3 to 38 days of age, another group was inoculated with 1 ml of IBH virus containing 10^6.5 EID₅₀ per 0.2 ml. A third group was given both ochratoxin-A and infected with IBH virus. The fourth group served as the control. Anaemia was observed in all three treated groups but the changes were more pronounced in the combined group. The biochemical changes also suggested a cumulative damaging effect by ochratoxin-A and IBH virus.     

Preliminary observations on the pharmacokinetics of CDRI compound 81/470 in calves

Veterinary Research Communications -     

Evidence from nucleic acid hybridization tests for geminivirus infection of ornamental crotons in India

Reduced growth of plants and excessive generalised and spotty yellowing of leaves occurred in ornamental crotons that were infected with a geminivirus, which was detected by spot hybridization tests using a cloned probe derived from DNA-A of acalypha yellow mosaic geminivirus. The croton virus was transmitted by the whitefly,Bemisia tabaci, toNicotiana tabacum andAcalypha indica, in which it caused leaf curl and yellow mosaic, respectively, but it was not transmitted to five other species. Infected crotons may therefore serve as reservoirs of a geminivirus that is able to infect a crop species.