Book Reviews

ASPECTS AND PROSPECTS OF PLANT GROWTH REGULATORS . Edited by B. J effcoat .
ADVANCES IN BOTANICAL RESEARCH, VOLUME 8 . Edited by H. W oolhouse
PLANTS AND THEIR ATMOSPHERIC ENVIRONMENT . 21st Symposium of The British Ecological Society. Edited by J. G race , E.D. F ord & P.G. J arvis
PLANT TISSUE CULTURE . Proceedings of the Beijing (Peking) Symposium
NITROGEN FIXATION . Edited by W.D.P. S tewart
THE BLUE LIGHT SYNDROME . Edited by H. S enghr
COMMENTARIES IN PLANT SCIENCE , Volume 2. Edited by H. S mith
NEW TRENDS IN THE CHEMISTRY OF NITROGEN FIXATION . Edited by J. C hatt , G eneral L.M. da C amara P ina & R.L. R ichards
ENVIRONMENTAL PHYSIOLOGY OF PLANTS . By A.H. F itter & R.K.M. H ay     

Alpha Sarcin, a New Antitumor Agent: II. Fermentation and Antitumor Spectrum

Aspergillus giganteus MDH 18894 was found to produce alpha sarcin, a new antitumor agent inhibitory to a number of different animal tumors. This culture produced culture filtrates that inhibited mouse sarcoma 180 at dilutions up to 1:32. Optimal fermentation conditions were established for shake flasks and 30-liter and 100-gal (378.5-liter) fermentors. Results from a variety of media were reported; however, the medium which yielded the most reproducible filtrates consisted of 2% corn starch, 1.5% beef extract (Difco), 2% peptone (Difco), and 0.5% sodium chloride. Purified preparations of 800 sarcoma 180 dilution units per mg were inactive against bacteria, yeasts, molds, actinomycetes, and protozoa, but were cytotoxic to several strains of mammalian cells. Alpha sarcin inhibited sarcoma 180 in mice at a dose of 62.5 μg per kg per day. A variety of other animal tumors were also inhibited by this compound.     

Phlorotannins versus other factors affecting epiphyte abundance on the kelp Ecklonia radiata

We examined factors affecting the abundance and distribution of epiphytes (fouling) on the sublittoral kelp Ecklonia radiata. We first assessed the importance of phlorotannins as chemical defences against epiphytes by (a) correlating epiphyte loads on different parts of the thallus with the phlorotannin content of those tissues, and (b) experimentally testing the effects of variation in phlorotannin concentration against the settlement and growth of gametes of Ulva lactuca, a common epiphyte in the system. Tissue phlorotannin content was, at best, only weakly related to epiphyte loads, with r ² values typically <0.10. Inhibition of Ulva gametes only occurred at concentrations >10 mg l⁻¹, which is 5 orders of magnitude greater than levels of phlorotannins in the water column around beds of E. radiata, and 1–3 orders of magnitude greater than estimated levels in the boundary layer at the surface of the plant. We concluded that phlorotannins have a negligible impact on patterns of epiphytism on E. radiata, and proceeded to investigate other factors influencing the distribution and abundance of epiphytes. In our samples the relative age of different parts of the thallus was strongly correlated with epiphyte abundance, with epiphyte densities greatest on the oldest tissue and least on the youngest. Distal parts of the thalli also had greater epiphyte loads than basal parts. Field experiments in which kelp tissue was suspended at two heights in an E. radiata forest for varying lengths of time confirmed the importance of the length of time that the tissue was in the water, and its height in the water column, to the development of an epiphyte community. Comparison of epiphyte loads on tissue from primary (smooth) and secondary (rough) laminae in these experiments indicated that surface rugosity also affected fouling. Macroherbivores were rare on E. radiata, and abundances of mesofauna and epiphytes were positively related, suggesting that grazers were not important determinants of patterns of epiphyte abundance. Although phlorotannins have been previously suggested to play an important role as defences against epiphytes, we suggest that water-soluble compounds such as phlorotannins are less likely to be effective defences against epiphytes than non-polar metabolites, which can adhere to the surface of the producing organism.     

Comparative nuclear and mitochondrial genome diversity in humans and chimpanzees

Restriction mapping and sequencing have shown that humans have substantially lower levels of mitochondrial genome diversity (d) than chimpanzees. In contrast, humans have substantially higher levels of heterozygosity (H) at protein-coding loci, suggesting a higher level of diversity in the nuclear genome. To investigate the discrepancy further, we sequenced a segment of the mitochondrial genome control region (CR) from 49 chimpanzees. The majority of these were from the Pan troglodytes versus subspecies, which was underrepresented in previous studies. We also estimated the average heterozygosity at 60 short tandem repeat (STR) loci in both species. For a total sample of 115 chimpanzees, d = 0.075 +/0 0.037, compared to 0.020 +/- 0.011 for a sample of 1,554 humans. The heterozygosity of human STR loci is significantly higher than that of chimpanzees. Thus, the higher level of nuclear genome diversity relative to mitochondrial genome diversity in humans is not restricted to protein-coding loci. It seems that humans, not chimpanzees, have an unusual d/H ratio, since the ratio in chimpanzees is similar to that in other catarrhines. This discrepancy in the relative levels of nuclear and mitochondrial genome diversity in the two species cannot be explained by differences in mutation rate. However, it may result from a combination of factors such as a difference in the extent of sex ratio disparity, the greater effect of population subdivision on mitochondrial than on nuclear genome diversity, a difference in the relative levels of male and female migration among subpopulations, diversifying selection acting to increase variation in the nuclear genome, and/or directional selection acting to reduce variation in the mitochondrial genome.      

Gene delivery into neuronal and glial cells by using a replication-deficient adenovirus vector: prospects for neurological gene therapy

We have used a recombinant adenovirus vector (E1−) expressing β-galactosidase to explore a novel mechanism with which to transfer genes into cells of the central nervous system (CNS). The replication-deficient adenovirus vector expressing β-galactosidase (RAd35) was propagated on a permissive helper cell line (293 cells). High level protein expression from the human cytomegalovirus immediate early promoter (hCMV IE) was obtained in a target cell population of RAd35 infected cultured neuronal and glial cell lines. Light microscopy showed that over 50% of the glial cells studied expressed β-galactosidase. Following retinoic acid treatment, RAd35 infected cell lines ND7/23, NG108 and NTera2, showed β-galactosidase expression in up to 90% of the cells. In addition, these cells showed morphological evidence of differentiation into neurons. This pattern of β-galactosidase expression was also observed in primary rat cerebella granule neuron cultures. In vivo studies were performed in Balb/c mice following direct intracranial injections of RAd35 into the brain. Cell sections showed a localised staining in the brain at the site of injection of the virus. Non-replicating adenovirus vectors are therefore highly efficient systems for delivering a transgene into brain cells. However, their broad cell tropism may limit their applications for genetic disorders in which a specific cell type is to be targeted for gene therapy. To address this problem, we have constructed adenovirus vectors which contain specific neuronal promoters and are currently assessing in vitro expression. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparative size and composition of yield from six Fijian reef fisheries

The size and composition of finfish yield from six Fijian reef fisheries was determined using catch records from a voluntary logbook scheme. A total of 172 logbooks were issued for 30-day periods in October 1992 and February and June 1993 and they provided information on 1369 fishing trips. Catch records were weighted, using the results of contemporaneous fishing activity and fleet size surveys, to provide yield estimates for each fishing ground ( qoliqoli ). Yield from all qoliqoli was dominated by Serranidae and Lethrinidae which were favoured for consumption and sale. Yields were expressed on the basis of reef area for fish from different trophic groups. Macroinvertebrate-feeders and piscivores accounted for more than half the yield in all qoliqoli and there were significant differences in area specific yield between qoliqoli. There was no evidence of fishers adopting more powerful fishing techniques or catching fish from lower trophic levels in order to maintain yield from any qoliqoli. This suggested that the fisheries examined were all capable of sustaining the reported yields of up to 3.4 tonne km⁻² qoliqoli year ⁻¹ or 10.2 tonne km⁻² coral reef year ⁻¹ and that in sites where yields were less they might be increased sustainably.