Comparative anatomy and systematics of woody Saxifragaceae. Aphanopetalum Endl.

The floral and vegetative anatomy of the small Australian genus Aphanopetalum were studied. Wood is described for the first time and is characterized by predominantly solitary pores, scalariform vessel element perforation plates with low bar numbers, imperforate tracheary elements with distinctly bordered pits, sparse axial parenchyma, and a combination of homocellular and heterocellular rayS. Starch occurs in both axial and ray parenchyma of the wood. Stems possess unilacunar, one-trace nodes and the uncommon feature of an endodermis with well-defined Casparian stripS. Leaves have anomocytic stomata, a bifacial mesophyll and semicraspedodromous venation or a combination of semicraspedodromous and brochidodromous venation. The tetramerous flowers are apetalous or have minute petals. The compound, half-inferior gynoecium consists of essentially totally united carpels. The pattern of floral vascularization resembles different Saxifragaceae sensu lalo in that the compound sepal-plane and petal-plane traces give rise to staman bundles as well as sepal, petal, and carpel wall venation in their respective planes. The ventral ovarian bundles are fused into a single ventral complex that subdivides at the top of the ovary to form ventral bundles and to supply the one ovule in each locule. Vegetative and floral features provide compelling evidence to suggest that Aphanopetalum has its nearest relatives among the Saxifragaceae sensu lato rather than Cunoniaceae. The genus is probably best treated as forming its own subfamily (or family) among the saxifragaean alliance.     

Mitochondrial DNA control region polymorphisms: genetic markers for ecological studies of marine turtles

We describe a rapid and sensitive method for the detection of population-specific genetic markers in mitochondrial DNA (mtDNA) and the use of such markers to analyse population structure of marine turtles. A series of oligonucleotide primers specific for the amplification of the mtDNA control region in Cheloniid turtles were designed from preliminary sequence data. Using two of these primers, a 384–385-bp sequence was amplified from the 5′ portion of the mtDNA control region of 15 green turtles Chelonia mydas from 12 different Indo-Pacific rookeries. Fourteen of the 15 individuals, including some with identical whole-genome restriction fragment patterns, had sequences that differed by one or more base substitutions. Analysis of sequence variation among individuals identified a total of 41 nucleotide substitutions and a 1-bp insertion/deletion. Comparison with evidence from whole-genome restriction enzyme analysis of the same individuals indicated that this portion of the control region is evolving approximately eight times faster than the average rate and that the sequence analysis detected approximately one fifth of the total variation present in the genome. Restriction enzyme analysis of amplified products from an additional 256 individuals revealed significant geographic structuring in the distribution of mtDNA genotypes among five of the 10 rookeries surveyed extensively. Additional geographic structuring of genotypes was identified through denaturing gradient gel electrophoresis (DGGE) of amplified products. Only two of the 10 rookeries surveyed could not be differentiated, indicating that the Indo-Pacific C. mydas include a number of genetically differentiated populations, with minimal female-mediated gene flow among them. Important applications for genetic markers in the conservation and management of marine turtles include the identification of appropriate demographic units for research and management (i.e. genetically discrete populations) and assessment of the composition of feeding and harvested populations.     

Alternative Reproductive Tactics in Spiders

The comparative study of reproduction at the level of populationand individual is a relatively recent development in spiderresearch. Such study is necessary to describe and examine alternativereproductive tactics. Female spider tactics are related to adaptationsfor a carnivorous mode of feeding. Being the larger of the sexes,the female has the alternative of mating with or preying uponattending males. In web building spiders, which are generallysolitary, other female alternatives are related to characteristicsof a web used in prey capture. These alternatives include differentresponses when defending the web, and individually buildingthe web so that it does or does not contact another. Tacticsmay vary in communal species which build a sheet-like structure,as females may remain in the colony or emigrate and establisha small web. Male spiders usually search for females, and matingoccurs on or near a female retreat or web. A male may show differentalternatives in mate searching, demonstrate various courtshipand copulatory tactics, copulate or feed on the female's preywhile she feeds, and guard the female after mating or departand search for another female. Certain characteristics of femalesare related to these male alternatives, these characteristicsbeing: larger size and longer life expectancy as compared withthe male, carnivorous feeding, and sexual receptivity. Maleweb spiders may also use alternatives while defending positionon the female web. These alternatives are related to the designand placement of the web, and occasional web abandonment bythe female. Relevant literature is reviewed and research suggested.     

Eimeria beldingii n. sp. and Other Coccidia (Apicomplexa) of the Ground Squirrel Spermophilus beldingi1

Fecal samples of 36 ground squirrels, Spermophilus beldingi, from Tioga Pass (elev. ca. 3315 m) in the Sierra Nevada, California, yielded oocysts of Eimeria beckeri in nine squirrels, E. citelli in four squirrels, E. beldingii n. sp. in two squirrels, and degenerated, unidentifiable oocysts in ten squirrels. Eimeria beldingii n. sp. oocysts are ellipsoidal, 30–34 × 24–30 (mean 32 × 26) μm with a two-layered, rough, striated wall, without a micropyle or residuum, with polar granules; they contain ellipsoidal or ovoid sporocysts 11–15 × 9–12 (mean 13 × 10) μm with a Stieda body and residuum.     

AN ANTIGEN OF CHONDROITIN SULFATE PROTEOGLYCAN; A MARKER FOR CARTILAGE DIFFERENTIATION

Antisera to the chondroitin sulfate proteoglycan complex (CPG) of cartilage were used to study the specificity of the CPG-associated antigen as a biochemical marker for cartilage differentiation and to study the expression of differentiation by cultured chondrocytes. Of 7 tissues tested, antigen giving an identity reaction with this protein could be detected by the Ouchterlony double diffusion test in extracts of sternum and brain of 14-day chick embryos. Extracts of 2 non-cartilage tissues gave a reaction indicating that they contain a related, but not identical antigen.
Ouchterlony double diffusion tests showed that extracts of morphologically differentiated chondrocytes cultured in vitro contain the CPG-associated antigen. The radio-precipitin test, used to quantitate the rate of synthesis of this antigen, provided a measure of cartilage phenotype expression in culture. The cultured chondrocytes synthesized antigenic protein at a rate similar to that of 14-day sternum. In contrast to intact cartilage, however, the cultured chondrocytes released much of the newly synthesized antigen into the medium.
The possibility was explored that synthesis of the CPG-associated antigen might be characteristic of all cells in culture, and not a specific expression of the cartilage phenotype. However, skin fibroblast cultures only contained detectable antigen of the "partially identical" type.     

On the role of ß-carotene in the reaction center chlorophyll a antennae of photosystem I

Absorption and low temperature fluorescence emission spectra were measured on chloroplast thylakoids and on purified reaction center chlorophyll a-protein complexes of photosystem I, CP-a₁. A clear association between the presence of ß-carotene and the occurrence of far red absorbing and emitting chlorophyll a components of the reaction center antennae of photosystem I was demonstrated. For this study chloroplasts and CP-a₁ were obtained from normal and carotenoid deficient plant material of various sources. The experimental material included 1) lyophilized pea chloroplasts extracted with petroleum ether, 2) the carotenoid deficient mutant C-6E of Scenedesmus obliquus and 3) wheat chloroplasts derived from normal and SAN-9789 treated plants. Removal of carotenoids, most likely principally ß-carotene, caused a loss of long wavelength absorbing chlorophylls in chloroplasts and purified CP-a₁, and the loss or diminution of the long wavelength peak seen in the low temperature fluorescence emission spectrum. This association between ß-carotene and special chlorophyll a forms may explain both the photoprotective and antenna functions ascribed to ß-carotene. In the absence of carotenoids in wheat and in the Scenedesmus mutant, the chlorophyll a antenna of photosystem I was extremely photosensitive. A triplet-triplet resonance energy transfer from chlorophyll a to ß-carotene and a singlet-singlet energy transfer from excited ß-carotene to chlorophyll would explain the photoprotective and antenna functions, respectively. The role of this association in determining some of the fluorescence properties of photosystem I is also discussed.