Growth, nitrogen utilization and biodiesel potential for two chlorophytes grown on ammonium, nitrate or urea

Nitrogen removal from wastewater by algae provides the potential benefit of producing lipids for biodiesel and biomass for anaerobic digestion. Further, ammonium is the renewable form of nitrogen produced during anaerobic digestion and one of the main nitrogen sources associated with wastewater. The wastewater isolates Scenedesmus sp. 131 and Monoraphidium sp. 92 were grown with ammonium, nitrate, or urea in the presence of 5 % CO₂, and ammonium and nitrate in the presence of air to optimize the growth and biofuel production of these chlorophytes. Results showed that growth on ammonium, in both 5 % CO₂ and air, caused a significant decrease in pH during the exponential phase causing growth inhibition due to the low buffering capacity of the medium. Therefore, biological buffers and pH controllers were utilized to prevent a decrease in pH. Growth on ammonium with pH control (synthetic buffers or KOH dosing) demonstrated that growth (rate and yield), biodiesel production, and ammonium utilization, similar to nitrate- and urea-amended treatments, can be achieved if sufficient CO₂ is available. Since the use of buffers is economically limited to laboratory-scale experiments, chemical pH control could bridge the gap encountered in the scale-up to industrial processes.     

A Meta-Analysis of Retinoblastoma Copy Numbers Refines the List of Possible Driver Genes Involved in Tumor Progression

BackgroundWhile RB1 loss initiates retinoblastoma development, additional somatic copy number alterations (SCNAs) can drive tumor progression. Although SCNAs have been identified with good concordance between studies at a cytoband resolution, accurate identification of single genes for all recurrent SCNAs is still challenging. This study presents a comprehensive meta-analysis of genome-wide SCNAs integrated with gene expression profiling data, narrowing down the list of plausible retinoblastoma driver genes.MethodsWe performed SCNA profiling of 45 primary retinoblastoma samples and eight retinoblastoma cell lines by high-resolution microarrays. We combined our data with genomic, clinical and histopathological data of ten published genome-wide SCNA studies, which strongly enhanced the power of our analyses (N = 310).ResultsComprehensive recurrence analysis of SCNAs in all studies integrated with gene expression data allowed us to reduce candidate gene lists for 1q, 2p, 6p, 7q and 13q to a limited gene set. Besides the well-established driver genes RB1 (13q-loss) and MYCN (2p-gain) we identified CRB1 and NEK7 (1q-gain), SOX4 (6p-gain) and NUP205 (7q-gain) as novel retinoblastoma driver candidates. Depending on the sample subset and algorithms used, alternative candidates were identified including MIR181 (1q-gain) and DEK (6p gain). Remarkably, our study showed that copy number gains rarely exceeded change of one copy, even in pure tumor samples with 100% homozygosity at the RB1 locus (N = 34), which is indicative for intra-tumor heterogeneity. In addition, profound between-tumor variability was observed that was associated with age at diagnosis and differentiation grades.InterpretationSince focal alterations at commonly altered chromosome regions were rare except for 2p24.3 (MYCN), further functional validation of the oncogenic potential of the described candidate genes is now required. For further investigations, our study provides a refined and revised set of candidate retinoblastoma driver genes.     

Twelve polymorphic microsatellite loci from the Asian citrus psyllid,Diaphorina citri Kuwayama,the vector for citrus greening disease,huanglongbing

Twelve polymorphic microsatellite markers were developed from microsatellite‐enriched DNA libraries and mined from an expressed sequence tags library of Diaphorina citri, the vector of the citrus greening disease (huanglongbing). Analysis of 288 individuals from Florida, Texas, and Brazil showed that allelic diversity ranged from three to eight alleles per locus and observed and expected heterozygosities ranged from 0.014 to 0.569 and from 0.052 to 0.653, respectively. These variable microsatellite loci can provide means for assessing overall genetic variation and migration patterns for this agriculturally important pest species. This information can be used to aid in developing successful management strategies.     

Survival of boll weevil （Coleoptera： Curculionidae） adults after feeding on pollens from various sources

The survival of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, adults on non-cotton hosts in the Lower Rio Grande Valley （LRGV） of Texas was examined from 2001 to 2006. The success of the Boll Weevil Eradication Program, which was reintroduced into the LRGV in 2005, depends on controlling overwintering boll weevil populations. Laboratory studies were conducted using boll weevil adults that were captured in pheromone traps from September through March. The number of adults captured per trap declined significantly in the field from fall to the beginning of spring （3.5-7.0-fold）. The proportion of trapped males and females did not differ significantly. The mean weight of boll weevil adults captured in September was 13.3 mg, while those of captured adults from November to February were significantly lower and ranged from 6.7 to 7.8 mg. Our results show that boll weevil adults can feed on different plant pollens. The highest longevity occurred when adults were fed almond pollen or mixed pollens （72.6 days and 69.2 days, respectively） and the lowest when they fed on citrus pollen or a non-food source （9.7 days or 7.4 days, respectively）. The highest adult survival occurred on almond and mixed pollens [88.0%-97. 6% after 1st feeding period （10 days）, 78.0%-90.8% after 3rd feeding period （10 days）, 55. 0%-83.6% after 5th feeding period （10 days）, and 15.2%-32.4% after lOth feeding period （10 days）]. The lowest adult survival occurred on citrus pollen [52.0%-56.0% after 1st feeding period （10 days）, 13.3% after 3rd and 5th feeding periods （10 days）, and 0 after 6th feeding period （10 days）]. Pollen feeding is not a behavior restricted to adult boll weevils of a specific sex or physiological state. Understanding how boll weevil adults survive in the absence of cotton is important to ensure ultimate success of eradicating this pest in the subtropics.     

A new workerless inquiline in the Lower Attini (Hymenoptera: Formicidae), with a discussion of social parasitism in fungus‐growing ants

Ant inquilines are obligate social parasites, usually lacking a sterile worker caste, which are dependent on their hosts for survival and reproduction. Social parasites are rare among the fungus‐gardening ants (Myrmicinae: tribe Attini) and only four species are known until now, all being inquilines from the Higher Attini. We describe Mycocepurus castrator sp.n. , the first inquiline social parasite to be discovered in the Lower Attini. Our study of the parasite's behaviour and life history supports the conclusion drawn from external morphology: Mycocepurus castrator is an evolutionarily derived inquiline parasite of Mycocepurus goeldii. Inquilines are of great interest to evolutionary biology because it is debated if they originated via sympatric or allopatric speciation. We discuss the life history evolution, behaviour and morphology of socially parasitic, fungus‐growing ants.     

Species-specific and conserved epitopes on mouse and human E-selectin important for leukocyte adhesion

The cdk5 and its activator p35 constitute one of the main tau-phosphorylating systems in neuronal cells. Under normal conditions for neurons, its activity is required for modulating tau involvement in neuronal polarity and in development of the mammalian central nervous system. Recently, we reported that the treatment of rat hippocampal cells in culture with fibrillary beta-amyloid (Abeta) results in deregulation of the protein kinase cdk5. The neurotoxic effects of Abeta fibrils were prevented by inhibition of cdk5 activity by butyrolactone I or by using antisense oligonucleotides that control the expression of this kinase. Here, we show that the Abeta-promoted increase of cdk5 activity is associated with changes in tau phosphorylation patterns and in the intraneuronal distribution of tau. In addition to hippocampal cells, deregulation of cdk5 was observed in other cell types. However, butyrolactone I prevented Abeta-induced cell death only in neuronal cells in which cdk5 activation was sensitive to Abeta fibrils. This lost of cdk5 regulation in hippocampal cells exposed to Abeta fibrils appears to be associated with an increase in the cdk5-p35 complex stability. Complex stabilization was sensitive to phosphorylation of cdk5. However, no changes in cdk5 and p35 mRNAs were observed, suggesting that the main effects on cdk5 occur at the posttranslational level. These studies indicate that cdk5 phosphorylation and the formation of an abnormally active cdk5-p35 complex are directly involved in the molecular paths leading to the neurodegenerative process of rat hippocampal neurons triggered by Abeta fibrils.     

Carbohydrate moieties can induce mediator release: a detailed characterization of two major timothy grass pollen allergens

Specific IgE binding to carbohydrate moieties of glycosylated allergens has been known for years, but the importance of these structures for the elicitation of allergic reactions is still a matter of debate. Because of their conserved carbohydrate structures, especially N-glycans have always been prime candidates for IgE cross-reactivity between allergens from unrelated species. The aim of our study was to determine whether carbohydrate structures on glycoproteins can by themselves elucidate allergic reactions. We characterized in detail the carbohydrate moieties of the major allergens Phl p 1 and Phl p 13 of timothy grass pollen (Phleum pratense L.) by performing tryptic digests followed by HPLC, N-terminal sequencing, sugar analysis, MALDI-TOF- and ESI-ICRFT-MS. Phl p 1 contains one N-glycan with one of the two glycoforms MMXF3 and M0XF3 and a single furanosidic arabinose, which is bound to a hydroxyproline residue in direct vicinity to the N-glycan. This O-glycosylation is probably due to an arabinosylation consensus sequence found in the N-terminal part of Phl p 1 and other group 1 allergens, but displayed no IgE-reactivity. Thus, Phl p 1 is monovalent with respect to its IgE-binding carbohydrate epitopes and showed no mediator release. In contrast, the carbohydrate moiety of Phl p 13, which carries four of the same N-glycans (like Phl p 1), can cross-link IgE-receptors via carbohydrate chains and elicits IL-4 release from basophils.     

Designed heterodimerizing leucine zippers with a ranger of pIs and stabilities up to 10(-15) M

We have designed a heterodimerizing leucine zipper system to target a radionuclide to prelocalized noninternalizing tumor-specific antibodies. The modular nature of the leucine zipper allows us to iteratively use design rules to achieve specific homodimer and heterodimer affinities. We present circular-dichroism thermal denaturation measurements on four pairs of heterodimerizing leucine zippers. These peptides are 47 amino acids long and contain four or five pairs of electrostatically attractive g <--> e' (i, i' +5) interhelical heterodimeric interactions. The most stable heterodimer consists of an acidic leucine zipper and a basic leucine zipper that melt as homodimers in the micro (T(m) = 28 degrees C) or nanomolar (T(m) = 40 degrees C) range, respectively, but heterodimerize with a T(m) >90 degrees C, calculated to represent femtamolar affinities. Modifications to this pair of acidic and basic zippers, designed to destabilize homodimerization, resulted in peptides that are unstructured monomers at 4 microM and 6 degrees C but that heterodimerize with a T(m) = 74 degrees C or K(d(37)) = 1.1 x 10(-11) M. A third heterodimerizing pair was designed to have a more neutral isoelectric focusing point (pI) and formed a heterodimer with T(m) = 73 degrees C. We can tailor this heterodimerizing system to achieve pharmacokinetics aimed at optimizing targeted killing of cancer cells.