John Evans announces the question to which all three of these books respond in his title: What is a human? And in the subtitle, he indicates the reason many people today are concerned about the answers offered to that question: what the different answers mean for human rights. As the debates about the fate of a fetus or comatose patient show, definitions of what is human can determine who lives or dies.

The demonstrated willingness of ten knowledgeable scholars to read and comment on parts of my work is, indeed, a great honor. As Mary Keys's introductory remarks show, the contributors are friends. However, although their comments are generally appreciative, they are by no means uncritical. I thus welcome the opportunity to respond to them.

Red vent syndrome (RVS) has previously been reported in returning wild Atlantic salmon, Salmo salar from Canada, Iceland, Ireland, Norway and the UK. Affected fish show reddening and swelling in the perianal/vent area, with scale loss, ulceration and bleeding in severe cases. Studies in the UK and elsewhere report the condition to be induced by Anisakis simplex sensu stricto (s.s.) larvae. This parasite, commonly reported in several marine fish species, is typically found in the body cavity and the skeletal muscle, but has recently been reported within the vent tissues of salmon. This latter finding may reflect greater efforts in examining this body portion due to current awareness of the parasite presence in this atypical location. Based on clinical observations, affected fish are classified into three categories according to the severity of the external lesions, but quantification of the vent parasite numbers in relation to the categories, and assessment of the relative importance of this area as a site of infestation, are missing to date. This investigation aimed to provide data on parasite number and distribution in the viscera, skeletal muscle, peduncle and vent area and to confirm the identity of the larvae found in the vent and the viscera. The study showed the perianal/vent region harbours the highest total number of A. simplex larvae per fish and, proportionally to fish biomass, is the most heavily infested body location irrespective of external severity levels of RVS.

Silicon nanoparticles (Si NPs) were synthesized by plasma enhanced chemical vapor deposition (PECVD) using silane as a silicon source. Allylamine was used as passivation ligands to form water-soluble Si NPs. Finally, aqueous asymmetric flow field-flow fractionation was used to successfully separate the polydisperse Si NPs into monodisperse Si NP fractions.

The YAG/ consensus sequence at the 3′ end of introns (the slash indicates the location of the 3′ splice site) is essential for catalysis of the second step of pre-mRNA splicing. Little is known about the interactions formed by these three nucleotides in the spliceosome. Although previous observations have suggested that the G of the YAG/ interacts with the first nucleotide of the /GUA consensus sequence at the 5′ end of the intron, additional interactions have not been identified. Here we report several striking genetic interactions between A+3 of the 5′ /GUA with Y−3 of the 3′ YAG/ and G50 of the highly conserved ACAGAG motif in U6 snRNA. Two mutations in U6 G50 of the ACAGAG can weakly suppress two mutations in A+3 of the 5′ /GUA. This suppression is significantly enhanced upon the inclusion of a specific mutation Y−3 in the 3′ YAG/. RNA analysis confirmed that the severe splicing defect observed in A+3 and Y−3 double mutants can be rescued to near wild-type levels by the mutations in U6 G50. The contributions of each mutation to the genetic interaction and the strong position specificity of suppression, combined with previous findings, support a model in which the 5′ /GUA and the GAG of U6 function in binding the 3′ YAG/ during the second catalytic step.

Semiconductor quantum dots of cadmium sulfide, CdS, are approximately the size of proteins and are photoluminescent in the red, yellow, or green, depending on surface preparation. This photoluminescence is very sensitive to the Nature and amount of adsorbates. We have found that DNAs with intrinsic curvature adsorb more strongly to the surface of 47 Å CdS quantum dots, as judged by concentration-dependent changes in photoluminescence. The binding constants we obtain are similar to those found for nonspecific protein-DNA interactions. The surface groups of the CdS substrate also influence DNA adsorption. Thus these protein-sized colloidal particles can be used in chemical sensing applications for curved or kinked DNA; DNA with unusual structures is thought to influence biological function such as transcription.

An inhibition ELISA (enzyme-linked immunosorbent assay) was developed for the determination of caseinomacropeptide (CMP) in order to estimate the proteolysis of κ-casein due to the enzymes of psychrotrophic bacteria in bulk raw milk. The CMP present in milk was quantified specifically by an antibody. The limit of detection was ∽ 0·1 μg/ml and the CV was < 10%. This method was used to study the proteolytic activity of three strains of psychrotrophic Pseudomonas fluorescens in raw milk and to analyse different raw milk samples supplied by four dairy plants. The proteolytic activity for different strains of psychrotrophs and for different milk samples varied considerably, but no correlation was established between the level of microbial flora and κ-casein proteolysis. It is thus not possible to determine the extent of proteolysis from the bacterial count alone. However, by CMP determination in bulk raw milk samples after 6 d storage at 4°C, the mean κ-casein proteolysis was ∽ 4%. Among the milk samples analysed that contained < 107 cfu psychrotrophs/ml, 30% exhibited a proteolysis of κ-casein < 0·5%, i.e. < 5μg CMP/ml.