Kristine Bonnevie,Tine Tammes and Elisabeth Schiemann in Early Genetics: Emerging Chances for a University Career for Women

The beginning of the twentieth century saw the emergence of the discipline of genetics. It is striking how many female scientists were contributing to this new field at the time. At least three female pioneers succeeded in becoming professors: Kristine Bonnevie (Norway), Elisabeth Schiemann (Germany) and the Tine Tammes (The Netherlands). The question is which factors contributed to the success of these women’s careers? At the time women were gaining access to university education it had become quite the norm for universities to be sites for teaching and research. They were still expanding: new laboratories were being built and new disciplines were being established. All three women benefited from the fact that genetics was considered a new field promising in terms of its utility to society; in the case of Tammes and Schiemann in agriculture and in the case of Bonnevie in eugenics. On the other hand, the field of genetics also benefited from the fact that these first female researchers were eager for the chance to work in science and wanted to make active contributions. They all worked and studied in environments which, although different from one another, were positive towards them, at least at the start. Having a patron was generally a prerequisite. Tammes profited from her teacher’s contacts and status. Bonnevie made herself indispensable through her success as a teacher and eventually made her position so strong that she was no longer dependent on a single patron. The case of Schiemann adds something new; it shows the vulnerability of such dependency. Initially, Schiemann’s teacher had to rely on the first generation of university women simply because he was unable to attract ambitious young men to his institute. In those early, uncertain years of the new discipline, male scientists tended to choose other, better established, and more prestigious disciplines. However, when genetics itself had become an established field, it also became more attractive to men. Our case studies also demonstrate that a new field at first relatively open to women closes its doors to them once it becomes established.     

Bystander suppression of collagen-induced arthritis in mice fed ovalbumin

We wanted to assess whether B-cell and/or T-cell responses to collagen and thereby the course of collagen-induced arthritis could be suppressed by regulatory mechanisms associated with oral tolerance to an unrelated protein. DBA/1 mice were fed ovalbumin (OVA)-containing pellets ad libitum for 1 week and subsequently coimmunized twice, with a mixture of bovine collagen type II (BCII) and OVA in Freund's complete adjuvant. Mice fed OVA before coimmunization with BCII and OVA had significantly lower arthritic scores than mice immunized with BCII only. Their body weight increased during the study period and their anti-BCII antibody activity was significantly IgG_2a lower. The frequency of spleen cells producing IgG anti-BCII antibody was also reduced. Coimmunization per se slightly ameliorated the development of arthritis, resulting in an early, transient reduction. It resulted in significantly higher IgG₁ anti-BCII antibody activity and increased splenocyte secretion of IFN-γ and IL-10 in response to BCII. Our findings demonstrate that OVA-specific regulatory events induced by feeding OVA, i.e. bystander suppression, reduced the severity of arthritis in animals immunized with BCII and OVA. Anti-BCII specific antibody responses and cytokine secretion by types 1 and 2 T helper cells were also decreased.     

B30.2-like domain proteins: update and new insights into a rapidly expanding family of proteins

The B30.2 domain is a conserved region of around 170 amino acids associated with several different protein domains, including the immunoglobulin folds of butyrophilin and the RING finger domain of ret finger protein. We recently reported several novel members of this family as well as previously undescribed protein families possessing the B30.2 domain. Many proteins have subsequently been found to possess this domain, including pyrin/marenostrin and the midline 1 (MID1) protein. Mutations in the B30.2 domain of pyrin/marenostrin are implicated in familial Mediterranean fever, and partial loss of the B30.2 domain of MID1 is responsible for Opitz G/BBB syndrome, characterized by developmental midline defects. In this study, we scrutinized the available sequence data bases for the identification of novel B30.2 domain proteins using highly sensitive database-searching tools. In addition, we discuss the chromosomal localization of genes in the B30.2 family, since the encoded proteins are likely to be involved in other forms of periodic fever, autoimmune, and genetic diseases.      

Mechanism of Formation of Novel Covalent Drug·DNA Interstrand Cross-Links and Monoadducts by Enediyne Antitumor Antibiotics

The potent enediyne antitumor antibiotic C1027 has been previously reported to induce novel DNA interstrand cross-links and drug monoadducts under anaerobic conditions [Xu et al. (1997) J. Am. Chem. Soc. 119, 1133-1134]. In the present study, we explored the mechanism of formation of these anaerobic DNA lesions. We found that, similar to the aerobic reaction, the diradical species of the activated drug initiates anaerobic DNA damage by abstracting hydrogen atoms from the C4', C1', and C5' positions of the A1, A2, and A3 nucleotides, respectively, in the most preferred 5'GTTA1T/5'ATA2A3C binding sequence. It is proposed that the newly generated deoxyribosyl radicals, which cannot undergo oxidation, likely add back onto the nearby unsaturated ring system of the postactivated enediyne core, inducing the formation of interstrand cross-links, connecting either A1 to A2 or A1 to A3, or drug monoadducts mainly on A2 or A3. Comparative studies with other enediynes, such as neocarzinostatin and calicheamicin gamma1I under similar reaction conditions indicate that the anaerobic reaction process is a kinetically competitive one, depending on the proximity of the drug unsaturated ring system or dioxygen to the sugar radicals and their quenching by other hydrogen sources such as solvent or thiols. It was found that C1027 mainly generates interstrand cross-links, whereas most of the anaerobic lesions produced by neocarzinostatin are drug monoadducts. Calicheamicin gamma1I was found to be less efficient in producing both lesions. The anaerobic DNA lesions induced by enediyne antitumor antibiotics may have important implications for their potent cytotoxicity in the central regions of large tumors, where relative anaerobic conditions prevail.     

The scaling and structure of aquatic animal wakes

Animal generated water movements are visualized and quantifiedusing two-dimensional particle image velocimetry (PIV). Theresulting vector flow fields allow for the study of the distributionof velocity, vorticity and vortices. Structural and temporalaspects of animal-induced flows covering a range of Reynolds(Re) numbers between less than 1 to more than 10⁴ are presented. Maps of flow induced by continuous foraging and intermittentescape responses of tethered nauplius and copepodid stages ofthe marine copepod Temora longicornis offer insight in viscosity-dominatedflow regimes. Fast escape responses of the equally sized largestnauplius stage and the smallest copepodid stage are compared.The nauplius moves by generating a viscous flow pattern withhigh velocities and vorticity; the copepodid moves by usinginertial effects to produce a vortex ring with a rearward jetthrough the center. Larvae and small adult fish (zebra danio) use a burst-and-coast-swimmingmode at Re numbers up to 6,000, shedding a vortex ring withthe associated jet at the tail during the burst phase. Flowpatterns during the coasting phase differ between the smalllarvae and larger adults due to the changes in importance ofviscosity. A 12 cm long mullet swimming in a continuous mode generatesa chain of vortex rings with a backward undulating jet throughthe centers of the rings at Re numbers of 4 x 10⁴ in inertia-dominatedregimes. Our empirical results provide realistic insight in the scaleeffects determining the morphology of the interactions betweenanimals and water.     

Mechanistic aspects of biosynthesis of silver nanoparticles by several <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> strains

Extracellular production of metal nanoparticles by several strains of the fungus Fusarium oxysporum was carried out. It was found that aqueous silver ions when exposed to several Fusarium oxysporum strains are reduced in solution, thereby leading to the formation of silver hydrosol. The silver nanoparticles were in the range of 20–50 nm in dimensions. The reduction of the metal ions occurs by a nitrate-dependent reductase and a shuttle quinone extracellular process. The potentialities of this nanotechnological design based in fugal biosynthesis of nanoparticles for several technical applications are important, including their high potential as antibacterial material.     

Riding the waves: the role of the body wave in undulatory fish swimming

A continuously swimming mullet modulates its thrust productionby changing slip-the ratio between its swimming speed U andthe speed V with which the body wave travels down its body.This variation in thrust is reflected in the wake of the fish.We obtained 2-dimensional impressions of the wake behind a mulletswimming at a slip of 0.7 equivalent to active swimming, ata slip of 0.9 close to free-wheeling, and at a slip of 1.1 whenthe fish is braking. Independent of the slip, vortices are shedat the tail when the tail tip reaches its maximum lateral excursion.The manner in which the wake changes as it decays depends onthe degree of slip: At a slip well below unity, the wake decayswithout any qualitative changes in shape, the medio-frontalcross section of the mature wake consists of a double row ofalternating vortices separated by an undulating jet, and theangle between the jet flow and the mean path of motion is closeto 45°; at a slip above unity, the vortices stretch outlaterally and the mature wake resembles a single row of ovalvortices with two vortex cores, and the jet between the vorticesis almost perpendicular to the mean path of motion; the wakeat slip of 0.9 exhibits a pattern intermediate between the wakesat slips 0.7 and 0.9 with slightly elongate vortices and a jetangle of 61°.     

On the reaction of potato starch with isocyanates

The reactions of potato starch in aqueous suspension with some isocyanates were investigated. In contrast to previously reported results we found that no starch carbamates were formed but only the corresponding urea compounds. These urea compounds were physically bound to the potato starch and could be washed from the starch by several organic solvents.