The Evolution of Feeding Mechanics in the Danioninae, or Why Giant Danios Don't Suck Like Zebrafish.

By linking anatomical structure to mechanical performance we can improve our understanding of how selection shapes morphology. Here we examined the functional morphology of feeding in fishes of the subfamily Danioninae (order Cypriniformes) to determine aspects of cranial evolution connected with their trophic diversification. The Danioninae comprise three major lineages and each employs a different feeding strategy. We gathered data on skull form and function from species in each clade, then assessed their evolutionary dynamics using phylogenetic-comparative methods. Differences between clades are strongly associated with differences in jaw protrusion. The paedomorphic Danionella clade does not use jaw protrusion at all, members of the Danio clade use jaw protrusion for suction production and prey capture, and members of the sister clade to Danio (e.g., Devario and Microdevario) use jaw protrusion to retain prey after capture. The shape of the premaxillary bone is a major determinant of protrusion ability, and premaxilla morphology in each of these lineages is consistent with their protrusion strategies. Premaxilla shapes have evolved rapidly, which indicates that they have been subjected to strong selection. We compared premaxilla development in giant danio (Devario aequipinnatus) and zebrafish (Danio rerio) and discuss a developmental mechanism that could shift danionine fishes between the feeding strategies employed by these species and their respective clades. We also identified a highly integrated evolutionary module that has been an important factor in the evolution of trophic mechanics within the Danioninae.

Association between regional brain volumes and clozapine response in schizophrenia.

BACKGROUND: Clozapine has shown considerable therapeutic promise in the treatment of schizophrenia; however, the clinical risks and initial high treatment costs associated with its administration motivate the search to identify patients who will best respond. Neuroimaging studies have suggested that prefrontal sulcal prominence may be a predictor of nonresponsiveness. METHODS: We used magnetic resonance imaging (MRI) to test whether volumes in any cortical regions of the brain were associated with symptom improvement with clozapine treatment. The 21 schizophrenic men studied were clinically evaluated during treatment with typical neuroleptics (baseline) and after a mean of 6.2 months treatment with clozapine (final dose 300-900, median = 562 mg/day). At least a 20% improvement on total Brief Psychiatric Rating Scale (BPRS) was seen in 47.6% of the schizophrenics. Clinical improvement was regressed on baseline differences in clinical severity, and the residual scores were related to MRI values. RESULTS: Patients with larger anterior superior temporal lobe cerebrospinal fluid volumes (primarily sylvian fissure) showed greater improvement on total BPRS and withdrawal/retardation symptoms. CONCLUSIONS: Even schizophrenics with significant brain dysmorphology can have a positive clinical response to clozapine.

An association between low levels of 5-HIAA and HVA in cerebrospinal fluid and early mortality in a diagnostically mixed psychiatric sample.

We followed up a sample of psychiatric patients (diagnoses predominantly schizophrenia and depression) who had participated in in-patient studies of their CSF over the past 15 years. The status of 73 former patients was confirmed, of whom 12 had died. Seven of these patients died at age < or = 40, largely of suicide, homicide, or accidental causes. These seven patients had significantly lower CSF 5-HIAA and HVA than living control patients. There were significant direct correlations between age at death and both CSF 5-HIAA and HVA in the deceased patients. The results offer support for CSF monoamine metabolites relating to early death in a diagnostically diverse sample of psychiatric patients.

Left-handedness in male schizophrenic patients is associated with increased impairment on the Luria-Nebraska Neuropsychological Battery.

Several studies suggest increased mixed and left-handedness in schizophrenia. This is of interest as early cerebral injury can result in increased left-handedness and some investigations have suggested a role for early developmental insult (e.g., birth complications) in schizophrenia. We administered the Luria-Nebraska Neuropsychological Battery (LNNB) to 24 left-handed male schizophrenic patients and a separate group of 24 right-handed schizophrenic patients who were age and education matched to the left-handed patients. The test protocol also was administered to 15 left-handed non-psychiatric control subjects and 15 right-handed controls. Direct comparisons (t-test) of the left- to right-handed schizophrenics revealed that the left-handed patients showed significantly greater impairment on several LNNB measures sensitive to cognitive deficits in schizophrenia. There were no differences between left- and right-handed control subjects. A further 2 X 2 ANOVA pooling all subjects noted several significant interactions between handedness and diagnostic group. The findings suggest a unique interaction between left-handedness and neuropsychological impairment in schizophrenia and could support a relationship between left-handedness, early cerebral insult, and cognitive deficits.

A quinoline fluorescence method for visualizing and assaying the histochemically reactive zinc (bouton zinc) in the brain.

A histochemical method for staining CNS zinc by the stoichiometric formation of zinc: quinoline fluorescent chelates is described. Four congeners of quinoline have been tested, and two found to be useful for histochemistry. The procedure is a one-step method, suitable for fresh-frozen and fixed tissue sections alike. The quinoline fluorescence selectively labels the CNS regions (such as hippocampus, amygdala) shown by prior histochemical procedures to be rich in histochemically reactive zinc in axon boutons and therefore appears to be a specific marker for the bouton zinc. Microfluorometric data indicate that the fluorochrome can be used for quantitative estimates of CNS zinc pools as well as qualitative studies of localization.

Casein production during differentiation of mammary epithelial cells in collagen gel culture.

Mouse mammary epithelial cells cultivated on floating collagen gels secrete, as judged by immunoblotting, the full array of caseins found in mouse milk. The secreted caseins are all phosphorylated and have estimated minimum molecular weights (MWs) of 45, 40, 27, and 23 kD in SDS-PAGE. Intracellular caseins of epithelia from collagen gel cultivation or from lactating mammary glands are a combination of mature caseins identical with the secreted molecules and novel caseins whose apparent size in SDS-PAGE is different from the secreted molecules. The novel caseins were shown to be non-phosphorylated species apparently insufficiently mature for secretion. Our data indicate that, with regard to casein expression, cultivation of mouse mammary epithelia on collagen gels essentially duplicates their behavior in the lactating mouse mammary glands.

Synthesis of novel calcium-dependent proteins associated with mammary epithelial cell migration and differentiation.

A class of proteins from mouse mammary epithelial cells has been isolated which, like the calcium-binding protein calmodulin (CaM), binds to phenothiazine in a calcium-dependent manner. These proteins do not bind to phenothiazine through binding to CaM; we infer that they are calcium-binding proteins, and that they may be related to the similarly isolated 'calcimedins' of Moore, P D & Dedman, J, J biol chem 257 (1982) 9663 [8]. In primary cultures of mouse mammary cells on collagen gels, synthesis of certain of these proteins is associated with the spreading of cells to form monolayers; failure of cells to spread and differentiate, through omission of serum from culture medium, results in the inhibition of calcium-binding protein synthesis, with the exception of CaM and a 15 kD species. The CaM/15 kD pair are prominent during all phases of culture, and are secreted during the secretory differentiation phase of culture (floating gels). We propose that these calcium-binding proteins play a specific role in the motility of mammary epithelial cells and that they may also be involved in mammary secretory differentiation.

Xanthine oxidase, an indicator of secretory differentiation in mammary cells.

Elevated levels of xanthine oxidase were found in (1) lactating mouse mammary glands, compared with virgin and midpregnant glands; and (2) primary mouse mammary cells cultured on floating collagen gels, compared with non-secretory cells on attached gels. In primary culture, increase in xanthine oxidase activity above a basal level coincided with secretory activity as measured by casein production; intracellular levels of casein and xanthine oxidase showed a high degree of correspondence. It is suggested that xanthine oxidase levels can be used as an indicator of in vivo and in vitro secretory differentiation in mammary epithelial cells.

Flagellar elongation and shortening in Chlamydomonas. The use of cycloheximide and colchicine to study the synthesis and assembly of flagellar proteins.

Flagella can be removed from the biflagellate Chlamydomonas and the cells begin to regenerate flagella almost immediately by deceleratory kinetics. Under usual conditions of deflagellation, more than 98% of all flagella are removed. Under less drastic conditions, cells can be selected in which one flagellum is removed and the other left intact. When only one of the two flagella is amputated, the intact flagellum shortens by linear kinetics while the amputated one regenerates. The two flagella attain an equal intermediate length and then approach their initial length at the same rate. A concentration of cycloheximide which inhibits protein synthesis permits less than one-third of each flagellum to form when both flagella are amputated. When only one is amputated in cycloheximide, shortening proceeds normally and the degree of elongation in the amputated flagellum is greater than if both were amputated in the presence of cycloheximide. The shortening process is therefore independent of protein synthesis, and the protein from the shortening flagellum probably enters the pool of precursors available for flagellar formation. Partial regeneration of flagella occurs in concentrations of cycloheximide inhibitory to protein synthesis suggesting that some flagellar precursors are present. Cycloheximide and flagellar pulse-labeling studies indicate that precursor is used during the first part of elongation, is resynthesized at mid-elongation, and approaches its original level as the flagella reach their initial length. Colchicine completely blocks regeneration without affecting protein synthesis, and extended exposure of deflagellated cells to colchicine increases the amount of flagellar growth upon transfer to cycloheximide. When colchicine is applied to cells with only one flagellum removed, shortening continues normally but regeneration is blocked. Therefore, colchicine can be used to separate the processes of shortening and elongation. Radioautographic studies of the growth zone of Chlamydomonas flagella corroborate previous findings that assembly is occurring at the distal end (tip growth) of the organelle.

Flagellar motion and fine structure of the flagellar apparatus in Chlamydomonas.

The biflagellate alga Chlamydomonas reinhardi was studied with the light and electron microscopes to determine the behavior of flagella in the living cell and the structure of the basal apparatus of the flagella. During normal forward swimming the flagella beat synchronously in the same plane, as in the human swimmer's breast stroke. The form of beat is like that of cilia. Occasionally cells swim backward with the flagella undulating and trailing the cell. Thus the same flagellar apparatus produces two types of motion. The central pair of fibers of both flagella appear to lie in the same plane, which coincides with the plane of beat. The two basal bodies lie in a V configuration and are joined at the top by a striated fiber and at the bottom by two smaller fibers. From the area between the basal bodies four bands of microtubules, each containing four tubules, radiate in an X-shaped pattern, diverge, and pass under the cell membrane. Details of the complex arrangement of tubules near the basal bodies are described. It seems probable that the connecting fibers and the microtubules play structural roles and thereby maintain the alignment of the flagellar apparatus. The relation of striated fibers and microtubules to cilia and flagella is reviewed, particularly in phytoflagellates and protozoa. Structures observed in the transitional region between the basal body and flagellar shaft are described and their occurrence is reviewed. Details of structure of the flagellar shaft and flagellar tip are described, and the latter is reviewed in detail.