Optimization of an acoustic cell filter with a novel air-backflush system

Increasing worldwide demand for mammalian cell production capacity will likely be partially satisfied by a greater use of higher volumetric productivity perfusion processes. An important additional component of any perfusion system is the cell retention device that can be based on filtration, sedimentation, and/or acoustic technologies. A common concern with these systems is that pumping and transient exposure to suboptimal medium conditions may damage the cells or influence the product quality. A novel air-backflush mode of operating an acoustic cell separator was developed in which an injection of bioreactor air downstream of the separator periodically returned the captured cells to the reactor, allowing separation to resume within 20 s. This mode of operation eliminated the need to pump the cells and allows the selection of a residence time in the separator depending on the sensitivity of the cell line. The air-backflush mode of operating a 10L acoustic separator was systematically tested at 10(7) cells/mL to define reliable ranges of operation. Consistent separation performance was obtained for wide ranges of cooling airflow rates from 0 to 15 L/min and for backflush frequencies between 10 and 40 h(-1). The separator performance was optimized at a perfusion rate of 10 L/day to obtain a maximum separation efficiency of 92 +/- 0.3%. This was achieved by increasing the power setting to 8 W and using duty cycle stop and run times of 4.5 and 45 s, respectively. Acoustic cell separation with air backflush was successfully applied over a 110 day CHO cell perfusion culture at 10(7) cells/mL and 95% viability.     

A high-density genome-wide association screen of sporadic ALS in US veterans

Following reports of an increased incidence of amyotrophic lateral sclerosis (ALS) in U.S. veterans, we have conducted a high-density genome-wide association study (GWAS) of ALS outcome and survival time in a sample of U.S. veterans. We tested ∼1.3 million single nucleotide polymorphisms (SNPs) for association with ALS outcome in 442 incident Caucasian veteran cases diagnosed with definite or probable ALS and 348 Caucasian veteran controls. To increase power, we also included genotypes from 5909 publicly-available non-veteran controls in the analysis. In the survival analysis, we tested for association between SNPs and post-diagnosis survival time in 639 Caucasian veteran cases with definite or probable ALS. After this discovery phase, we performed follow-up genotyping of 299 SNPs in an independent replication sample of Caucasian veterans and non-veterans (ALS outcome: 183 cases and 961 controls; survival: 118 cases). Although no SNPs reached genome-wide significance in the discovery phase for either phenotype, three SNPs were statistically significant in the replication analysis of ALS outcome: rs6080539 (177 kb from PCSK2), rs7000234 (4 kb from ZNF704), and rs3113494 (13 kb from LOC100506746). Two SNPs located in genes that were implicated by previous GWA studies of ALS were marginally significant in the pooled analysis of discovery and replication samples: rs17174381 in DPP6 (p = 4.4×10⁻⁴) and rs6985069 near ELP3 (p = 4.8×10⁻⁴). Our results underscore the difficulty of identifying and convincingly replicating genetic associations with a rare and genetically heterogeneous disorder such as ALS, and suggest that common SNPs are unlikely to account for a substantial proportion of patients affected by this devastating disorder.     

Bufadienolides in different chromosomal races of Indian squill

Scilliphaeoside and anhydroscilliphaeosidin have been isolated from tetraploid Indian squill. The absence of scilliphaeoside in all populations of diploids and hexaploids and anhydrophaeosidin in diploids, triploids and hexaploids might be one of the reasons why they were not detected in previous studies.     

Genetic heterogeneity among the Hindus and their relationships with the other “Caucasoid” populations: New data on Punjab-Haryana and Rajasthan Indian States

The genetic structure of Rajasthan Hindus and Punjab-Haryana Hindus and Sikhs has been studied for ABO, RH, APOC2, C6, C7, F13A, F13B, HP, ORM1, ACP1, ADA, AK1, ESD, GLO1, PGD, PGM1 subtyping, and PGP. This is the first genetic survey on Hindus of Rajasthan. Furthermore, many of these markers have never been studied on Hindus before (APOC2, C6, 07, F13A, F13B, ORMl, PGP). These data, together with those previously available for Hindus, have been utilized to analyze the within-Hindus genetic heterogeneity by R_ST statistic and correspondence analysis. The genetic relationships of Hindus to other Causcasoid populations were also investigated. In the first analysis, two eastern states (Orissa and Andhra Pradesh) were found to be quite separate from each other and clearly distinct from the northwestern and western states. Out of the markers which could not be utilized in this analysis, PGM1 subtyping turned out to discriminate between the Dravidian—speaking and the Indo-Aryan-speaking Hindus. The second analysis shows a clear-cut separation of Hindus from Europeans, with Near Eastern and Middle Eastern populations genetically in an intermediate position. © 1995 Wiley-Liss, Inc.     

Seasonal variation in primary productivity in three tropical ponds

Summary Primary productivity values ranged from 1.5 to 15.8 gc/M²/day in Othakadai pond; 2.0 to 8.0 gc/M²/day in Teppakulam tank and 1.05 to 5.4 gc/M²/day in Yanamalai pond. Among the three ponds, highest annual yield was recorded in Othakadai pond (2000.2 gc/M²/yr) next in order comes Teppakulam tank (1211.8 gc/M²/yr) and lastly Yanamalai pond (810.7 gc/M²/yr). In all three ponds temperature and chlorophyll-a showed a more or less direct correlation to productivity values. Alkalinity values and productivity values showed a positive correlation in Othakadai and Yanamalai ponds, while no relationship between alkalinity and productivity could be established in Teppakulam tank.Formed part of a Ph. D. Thesis submitted to Madurai University.     

Plant regeneration through somatic embryogenesis from spear callus culture of Asparagus cooperi Baker

Somatic embryogenesis and plantlet formation were obtained from callus derived from the subapical region of spears of Asparagus cooperi Baker. Callus was obtained in Murashige and Skoog's medium supplemented with 1-naphthaleneacetic acid and kinetin. Increase in the concentration of potassium nitrate in subsequent subcultures resulted in the formation of embryos. Rapid multiplication of embryos was secured on transfer to a medium containing a different source of nitrogen and a low level (0.01 mg/1) of gibberellic acid. Media containing zeatin or gibberellic acid led to the formation of complete plantlets from embryos. Regenerated plants were cytologically and phenotypically stable.Abbreviations IBA Indole-3-butyric acid - NAA 1-Naphthaleneacetic acid - 2ip (2-Isopentenyl) adenine - BAP 6-Benzylaminopurine, GA,, Gibberellin - ABA Abscisic acid - MS Murashige and Skoog (1962) medium