Developmental failure after experimental activation of insect eggs

Summary

Eggs taken from the genital tracts of Venturia (Nemeritis) canescens (Hym., Ichneum.) and Psychoda cinerea (Dipt., Psychod.) can be activated by brief exposure to distilled water. However, embryogenesis fails soon unless some other conditions are met. These are mechanical deformation of the egg in Venturia, and mating in Psychoda. Development ceases at or soon after meiosis in Psychoda and in most Venturia eggs; the remaining Venturia eggs fail to form an orderly blastoderm although they contain hundreds of nuclei. In Venturia the anomalies are probably due to insufficient activation of some cytoplasmic component(s) while Psychoda eggs fail in the absence of some paternal contribution, possibly the sperm which in this case must enter the oocyte within the follicle.     

Consistency across Repeated Eyewitness Interviews: Contrasting Police Detectives’ Beliefs with Actual Eyewitness Performance

In the legal system, inconsistencies in eyewitness accounts are often used to discredit witnesses’ credibility. This is at odds with research findings showing that witnesses frequently report reminiscent details (details previously unrecalled) at an accuracy rate that is nearly as high as for consistently recalled information. The present study sought to put the validity of beliefs about recall consistency to a test by directly comparing them with actual memory performance in two recall attempts. All participants watched a film of a staged theft. Subsequently, the memory group (N = 84) provided one statement immediately after the film (either with the Self-Administered Interview or free recall) and one after a one-week delay. The estimation group (N = 81) consisting of experienced police detectives estimated the recall performance of the memory group. The results showed that actual recall performance was consistently underestimated. Also, a sharp decline of memory performance between recall attempts was assumed by the estimation group whereas actual accuracy remained stable. While reminiscent details were almost as accurate as consistent details, they were estimated to be much less accurate than consistent information and as inaccurate as direct contradictions. The police detectives expressed a great concern that reminiscence was the result of suggestive external influences. In conclusion, it seems that experienced police detectives hold many implicit beliefs about recall consistency that do not correspond with actual recall performance. Recommendations for police trainings are provided. These aim at fostering a differentiated view on eyewitness performance and the inclusion of more comprehensive classes on human memory structure.     

Breastfeeding and subsequent maternal visceral adiposity

Women gain visceral fat during pregnancy. Studies examining the impact of breastfeeding on maternal body composition are inconclusive. We examined the extent to which breastfeeding was associated with visceral adiposity in a sample of US women. This was a cross-sectional analysis of 351 women aged 45-58 years, who were free of clinical cardiovascular disease and had not used oral contraceptives or hormone replacement therapy in the 3 months prior to enrollment in the Study of Women's Health Across the Nation (SWAN)-Heart Study (2001-2003). History of breastfeeding was self-reported. Computed tomography was used to assess abdominal adiposity. Among premenopausal/early-peri-menopausal mothers, those who never breastfed had 28% greater visceral adiposity (95% confidence interval (CI): 11-49, P = 0.001), 4.7% greater waist-hip ratio (95% CI: 1.9-7.4, P < 0.001), and 6.49 cm greater waist circumference (95% CI: 3.71-9.26, P < 0.001) than mothers who breastfed all of their children for ≥3 months in models adjusting for study site; age; parity; years since last birth; socioeconomic, lifestyle, and family history variables; early adult BMI; and current BMI. In comparison to women who were nulliparous, mothers who breastfed all of their children for ≥3 months had similar amounts of visceral fat (P > 0.05). In contrast, premenopausal/early-peri-menopausal mothers who had never breastfed had significantly greater visceral adiposity (42% (95% CI: 17-70), P < 0.001), waist circumference (6.15 cm (95% CI: 2.75-9.56), P < 0.001), and waist-hip ratio (3.7% (95% CI: 0.69-6.8), P = 0.02) than nulliparous women. No significant relationships were observed among late peri-menopausal/postmenopausal women. In conclusion, until menopause, mothers who did not breastfeed all of their children for ≥3 months exhibit significantly greater amounts of metabolically active visceral fat than mothers who had breastfed all of their children for ≥3 months.     

Ectopic expression of human mTOR increases viability, robustness, cell size, proliferation, and antibody production of chinese hamster ovary cells

Engineering of mammalian production cell lines to improve titer and quality of biopharmaceuticals is a top priority of the biopharmaceutical manufacturing industry providing protein therapeutics to patients worldwide. While many engineering strategies have been successful in the past decade they were often based on the over‐expression of a single transgene and therefore limited to addressing a single bottleneck in the cell's production capacity. We provide evidence that ectopic expression of the global metabolic sensor and processing protein mammalian target of rapamycin (mTOR), simultaneously improves key bioprocess‐relevant characteristics of Chinese hamster ovary (CHO) cell‐derived production cell lines such as cell growth (increased cell size and protein content), proliferation (increased cell‐cycle progression), viability (decreased apoptosis), robustness (decreased sensitivity to sub‐optimal growth factor and oxygen supplies) and specific productivity of secreted human glycoproteins. Cultivation of mTOR‐transgenic CHO‐derived cell lines engineered for secretion of a therapeutic IgG resulted in antibody titers of up to 50 pg/cell/day, which represents a four‐fold increase compared to the parental production cell line. mTOR‐based engineering of mammalian production cell lines may therefore have a promising future in biopharmaceutical manufacturing of human therapeutic proteins. Biotechnol. Bioeng. 2011; 108:853–866. © 2010 Wiley Periodicals, Inc.     

Snapshots during the catalytic cycle of a histidine acid phytase reveal an induced-fit structural mechanism

Highly engineered phytases, which sequentially hydrolyze the hexakisphosphate ester of inositol known as phytic acid, are routinely added to the feeds of monogastric animals to improve phosphate bioavailability. New phytases are sought as starting points to further optimize the rate and extent of dephosphorylation of phytate in the animal digestive tract. Multiple inositol polyphosphate phosphatases (MINPPs) are clade 2 histidine phosphatases (HP2P) able to carry out the stepwise hydrolysis of phytate. MINPPs are not restricted by a strong positional specificity making them attractive targets for development as feed enzymes. Here, we describe the characterization of a MINPP from the Gram-positive bacterium Bifidobacterium longum (BlMINPP). BlMINPP has a typical HP2P-fold but, unusually, possesses a large α-domain polypeptide insertion relative to other MINPPs. This insertion, termed the U-loop, spans the active site and contributes to substrate specificity pockets underpopulated in other HP2Ps. Mutagenesis of U-loop residues reveals its contribution to enzyme kinetics and thermostability. Moreover, four crystal structures of the protein along the catalytic cycle capture, for the first time in an HP2P, a large ligand-driven α-domain motion essential to allow substrate access to the active site. This motion recruits residues both downstream of a molecular hinge and on the U-loop to participate in specificity subsites, and mutagenesis identified a mobile lysine residue as a key determinant of positional specificity of the enzyme. Taken together, these data provide important new insights to the factors determining stability, substrate recognition, and the structural mechanism of hydrolysis in this industrially important group of enzymes.     

The sister-group relationships of the largest family of lichenized fungi,Parmeliaceae (Lecanorales, Ascomycota)

Parmeliaceae is the largest family of lichen-forming fungi. In spite of its importance for fungal diversity, its relationships with other families in Lecanorales remain poorly known. To better understand the evolutionary history of the diversification of lineages and species richness in Parmeliaceae it is important to know the phylogenetic relationships of the closest relatives of the family. A recent study based on two molecular loci suggested that either Protoparmelia s. str. or a group consisting of Gypsoplaca and Protoparmelia s. str. were the possible sister-group candidates of Parmeliaceae, but that study could not distinguish between these two alternatives. Here, we used a four-locus phylogeny (nuLSU, ITS, RPB1, MCM7) to reveal relationships of Parmeliaceae with other potential relatives in Lecanorales. Maximum likelihood and Bayesian analyses showed that Protoparmelia is polyphyletic, with Protoparmelia s. str. (including Protoparmelia badia and Protoparmelia picea) being most closely related to Parmeliaceae s. str., while the Protoparmelia atriseda-group formed the sister-group to Miriquidica. Gypsoplaca formed the sister-group to the Parmeliaceae s. str. + Protoparmelia s. str. clade. Monophyly of Protoparmelia as currently circumscribed, and Gypsoplaca as sister-group to Parmeliaceae s. str. were both significantly rejected by alternative hypothesis testing.