Influence of medium, pH and temperature on L-asparaginase production by Thielavia terrestris, Malbranchea cinnamomea and Scytalidium thermophilum in submerged fermentation process was investigated. Maximum L-asparaginase production was... more
Influence of medium, pH and temperature on L-asparaginase production by Thielavia terrestris, Malbranchea cinnamomea and Scytalidium thermophilum in submerged fermentation process was investigated. Maximum L-asparaginase production was recorded in the glucose medium supplemented with 0.5% L-asparagine monohydrate on 8th day of incubation. Czapek-dox medium was the next proffered medium for both biomass and L-asparaginase production by the fungi under investigation. Among different pH tried, pH 7.0 was optimum for L-asparaginase production, while enzyme production was marginal in medium with 6.0-8.0. Temperature of 45°C and 50°C were optimum for T. terrestris for growth of M. cinnamomea and S. thermophilum respectively. Maximum L-asparaginase activity of all three fungi was recorded at 45°C with varying extent was recorded. Analysis of variance of the data revealed significant differences (p-0.05) among the different culture media, pH and temperature on the production of L-asparaginase. A significant and positive correlation coefficient (R) was also observed between the growth and L-asparaginase activity of T. terrestris (0.570), M. cinnamomea (0.947) and S. thermophilum (0.948). Conclusion the culture medium and factors like pH, incubation temperature and incubation period play an important role in the L-asparaginase production by all the three thermophilic caprophilous fungi.
The objective of this work was to characterize molecularly rabies viruses from Mexican skunks, by comparison of a portion of the viral P gene sequence with corresponding regions from other skunkadapted rabies virus variants and with... more
The objective of this work was to characterize molecularly rabies viruses from Mexican skunks, by comparison of a portion of the viral P gene sequence with corresponding regions from other skunkadapted rabies virus variants and with other genotype 1 rabies viruses that circulate in the Americas. Furthermore, incubation period and histopathologic lesions after virus inoculation by the intracerebral route in mice was characterized. According to the results of phylogenetic studies the Mexican skunk strains (Antigenic Variant (AV) 8 and AV10) are evolutionarily quite distinct. The AV10 isolate from South Baja California is quite closely related to the viruses that circulate in Californian skunks; while the AV8 isolate from San Luis Potosí was most closely related to the South central skunk strain that circulates in southern states such as Texas. These variations were reflected in some biological properties of both strains in mice.
RESUMEN El objetivo de este estudio fue la caracterización molecular y biológica del virus de la rabia en zorrillos de México, comparando una porción de la secuencia viral del gen P, con regiones correspondientes de variantes de virus... more
RESUMEN El objetivo de este estudio fue la caracterización molecular y biológica del virus de la rabia en zorrillos de México, comparando una porción de la secuencia viral del gen P, con regiones correspondientes de variantes de virus rábico adaptadas en zorrillos y ...
Alternative hosts and Incubation period of Botryodiplodia theobromae the causal of diplodia bark diseases on citrus. Citrus is one of the important horticulture commodities in South Kalimantan. Citrus growers in the region encounter... more
Alternative hosts and Incubation period of Botryodiplodia theobromae the causal of diplodia bark diseases on citrus. Citrus is one of the important horticulture commodities in South Kalimantan. Citrus growers in the region encounter diplodia disease caused by a ...
SUMMARYInfections with the malaria parasite Plasmodium vivax are noteworthy for potentially very long incubation periods (6–9 months), which present a major barrier to disease elimination. Increased sporozoite challenge has been reported... more
SUMMARYInfections with the malaria parasite Plasmodium vivax are noteworthy for potentially very long incubation periods (6–9 months), which present a major barrier to disease elimination. Increased sporozoite challenge has been reported to be associated with both shorter incubation and pre-patent periods in a range of human challenge studies. However, this evidence base has scant empirical foundation, as these historical analyses were limited by available analytic methods, and provides no quantitative estimates of effect size. Following a comprehensive literature search, we re-analysed all identified studies using survival and/or logistic models plus contingency tables. We have found very weak evidence for dose-dependence at entomologically plausible inocula levels. These results strongly suggest that sporozoite dosage is not an important driver of long-latency. Evidence presented suggests that parasite strain and vector species have quantitatively greater impacts, and the potentia...
A discrete dynamic model for human epidemics was developed in present study. The model included major parameters as transmission strength and its dynamic changes, mean incubation period, hospitalization time (i.e., the time from illness... more
A discrete dynamic model for human epidemics was developed in present study. The model included major parameters as transmission strength and its dynamic changes, mean incubation period, hospitalization time (i.e., the time from illness to hospitalization), non-hospitalization (i.e., outside hospitals) daily mortality,
non-hospitalization daily recovery rate, and hospitalization proportion (proportion of cases for hospitalization), etc. Sensitivity analysis of the model indicated the total cumulative cases significantly increased with the increase of initial transmission strength and hospitalization time. The total cumulative cases significantly decreased with the increase of transmission strength’s dynamic decline and hospitalization proportion, and decreased with the increase of non-hospitalization daily mortality and non-hospitalization daily recovery rate. The total cumulative cases significantly increased with the decrease of mean incubation period. Sensitivity analysis demonstrated that dynamic change of transmission strength is one of the most important and controllable factors. In addition, reducing the delay for hospitalization (i.e., hospitalization time) is much effective in weakening disease epidemic. Enhancing immunity to recover from the disease is of importance for increasing non-hospitalization recovery rate.
"""A delayed vector-bias model for malaria transmission with incubation period in mosquitoes is studied. The delay τ corresponds to the time necessary for a latently infected vector to become an infectious vector. We prove that the global... more
"""A delayed vector-bias model for malaria transmission with incubation period in mosquitoes is studied. The delay τ corresponds to the time necessary for a latently infected vector to become an infectious vector. We prove that the global stability is completely determined by the threshold parameter, R_0(tau). If R_0(tau)≤1, the disease-free equilibrium is globally asymptotically stable. If R_0(tau)>1 a unique endemic equilibrium exists and is globally asymptotically stable. We apply our results to Ross-MacDonald malaria models with an incubation period (extrinsic or intrinsic).
Keywords: Malaria transmission, time delay, global stability, Lyapunov functional.
