Endosymbiotic algae in rudists?

The supposition that rudists may have lived in association with endosymbiotic zooxanthellae has been tested by comparing the shell wall structure of the radiolitid genus Osculigera with the recent bivalve Corculum. It is concluded that the wall structure of the upper valve could have been able to provide endosymbiotic algae in the mantle with light.     

Monitoring of algae in Dutch rivers: does it meet its goals?

Observations on phytoplankton in the lower reaches of the rivers Rhine and Meuse were carried out in the framework of the national monitoring programme of the main water systems in The Netherlands. Seasonal changes in density and species composition were analysed to detect the major variables and to discuss whether this monitoring meets its goals. Phytoplankton reached peak densities of 140 and 65 μg L^-1 Chl a in the Rhine and Meuse, respectively. Overall density was correlated with seasonal variation in water discharge rather than with nutrient concentrations, that are high in both rivers. The position of sampling sites in relation to the downstream development of the plankton was very important, especially in the regulated Meuse. Despite hydrographic and chemical differences between the two rivers, many species, predominantly diatoms and green algae, were shared. The occurrence of the diatom Skeletonema subsalsum in the Rhine and the green algae Neodesmus danubialis, Micractinium pusillum and Pseudotetrastrum punctatum in the Meuse (1992, but not 1996) was interpreted as a feature related, respectively, to the high salinity of the Rhine and specific riverine conditions of the Meuse. In general the potamoplankton was characterised as an opportunistic assemblage exploiting the high nutrient contents and disturbed hydrography of both rivers. Nevertheless, the phytoplankton contributed to the characterisation of the present river communities, ones that differ rather strongly in historic records. Although year to year variation in phytoplankton density is mainly related to variation in water discharge, phytoplankton biomass did increase as a result of eutrophication over a period of decades. The widespread nature of many of today's potamoplankton species in the two rivers render these organisms less useful for indicating short-term changes in water quality. However the importance of phytoplankton in trophic relationships merits its inclusion in the monitoring of riverine ecosystems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Are red algae plants?

For 200 years prior to the 1938 publication of H. F. Copeland, all authorities (with one exception) classified red algae (Rhodophyta) within Kingdom Plantae or its equivalent. Copeland's reclassification of red algae within Kingdom Protista or Protoctista drew from an alternative tradition, dating to Cohn in 1867, in which red algae were viewed as the earliest or simplest eukaryotes. Analyses of ribosomal RNA (rRNA) sequence data initially favoured Copeland's reclassification. Many more rRNA gene (rDNA) sequences are now available from the eukaryote lineages most closely related to red algae, and based on these data, the hypothesis that red algae and green plants are sister groups cannot be rejected. An increasing body of sequence, intron-location and functional data from nuclear- and mitochondrially encoded proteins likewise supports a sister-group relationship between red algae and green plants. Submerging Kingdoms Plantae, Animalia and Fungi into Eukarya would provide a more natural framework for the eventual resolution of whether red algae are plants or prorists.     

Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied by combining a glasshouse experiment in which plants were exposed to various levels of UV-B radiation and field measurements in two freshwater systems dominated by charophytes in the Netherlands. The glasshouse experiment showed that charophytes were sensitive to UV-B radiation. UV-B radiation negatively affected growth, while it increased levels of DNA damage in Chara aspera. Moreover, the charophytes did not seem to develop UV-B screens to protect against UV-B radiation since no increase in UV-B absorbing compounds was found. At field conditions, both spectroradiometrical measurements and DNA dosimeters showed that UV-B radiation was attenuated quickly in both freshwater systems, indicating that UV-B does not reach the submerged charophyte vegetation. However, specific conditions, like fluctuating water tables, may result in UV-B exposure to charophytes for certain periods annually.     

Can telomerase be put in its place?

The Cajal body is an intriguing nuclear structure present in a great variety of plant, animal, and some fungal cells. Recent work on the ribonucleoprotein enzyme telomerase has indicated an unanticipated degree of intranuclear dynamics of both its RNA and protein subunits. In this issue, Jady et al. place the Cajal body on the intranuclear traffic route of telomerase RNA (Jady et al., 2004).     

Was globin evolution very rapid in its early stages?: A dubious case against the rate-constancy hypothesis

Summary Goodman et al's (1975) claim of accelerated evolution in the early stages of globin evolution is based on an erroneous assignment of the time of divergence of vertebrate myoglobin and hemoglobin. When this is corrected, there is no basis for their claim. The data are much more consistent with the nearly constant rate expected on the neutral mutation-random drift hypothesis than with the uneven rates expected if most amino acid changes were caused by substitution of favorable mutants through Darwinian selection. In addition, the majority of the codons determined by their maximum parsimony method have turned out to be wrong when compared to the actual nucleotide sequences of rabbit and human hemoglobins determined by direct sequencing.Contribution No. 1314 from the National Institute of Genetics, Mishima, 411 Japan.     

Can cell morphology in monolayer reveal its behaviour in aggregates?

The morphology of HeLa cells was altered to stellate shape by 0.2 – 1.0 mM butyric acid. At similar concentrations butyric acid did not alter the ability of HeLa cells to aggregate, but did inhibit the remodelling of the aggregates. Papaverine at 10 μM, on the other hand, had no effect on cells in monolayer, but severely inhibited the ability of cells to aggregate and the remodelling of the aggregates. Our results show that the effect of a drug on the morphology of HeLa cells in monolayer does not predict its effect in aggregates of cells which more faithfully approximate the behaviour of cells in tissue than the monolayer.     

Costs Of Using “Tiny Targets” to Control Glossina fuscipes fuscipes,a Vector of Gambiense Sleeping Sickness in Arua District of Uganda

IntroductionTo evaluate the relative effectiveness of tsetse control methods, their costs need to be analysed alongside their impact on tsetse populations. Very little has been published on the costs of methods specifically targeting human African trypanosomiasisDiscussionComparison with the updated cost of historical HAT vector control projects and recent estimates indicates that this work represents a major reduction in cost levels. This is attributed not just to the low unit cost of tiny targets but also to the organisation of delivery, using local labour with bicycles or motorcycles. Sensitivity analyses were undertaken, investigating key prices and assumptions. It is believed that these costs are generalizable to other HAT foci, although in more remote areas, with denser vegetation and fewer people, costs would increase, as would be the case for other tsetse control techniques.     

What's in a name? The case of cyanobacteria

A redefinition of the cyanobacterial lineage has been proposed based on phylogenomic analysis of distantly related nonphototrophic lineages. We define Cyanobacteria here as “Organisms in the domain bacteria able to carry out oxygenic photosynthesis with water as an electron donor and to reduce carbon dioxide as a source of carbon, or those secondarily evolved from such organisms.”     

The subspecies concept in butterflies: has its application in taxonomy and conservation biology outlived its usefulness?

Subspecies lie at the interface between systematics and population genetics, and represent a unit of biological organization in zoology that is widely used in the disciplines of taxonomy and conservation biology. In this review, we explore the utility of subspecies in relation to their application in systematics and biodiversity conservation, and briefly summarize species concepts and criteria for their diagnosis, particularly from an invertebrate perspective. The subspecies concept was originally conceived as a formal means of documenting geographical variation within species based on morphological characters; however, the utility of subspecies is hampered by inconsistencies by which they are defined conceptually, a lack of objective criteria or properties that serve to delimit their boundaries, and their frequent failure to reflect distinct evolutionary units according to population genetic structure. Moreover, the concept has been applied to populations largely comprising different components of genetic diversity reflecting contrasting evolutionary processes. We recommend that, under the general lineage (unified) species concept, the definition of subspecies be restricted to extant animal groups that comprise evolving populations representing partially isolated lineages of a species that are allopatric, phenotypically distinct, and have at least one fixed diagnosable character state, and that these character differences are (or are assumed to be) correlated with evolutionary independence according to population genetic structure. Phenotypic character types include colour pattern, morphology, and behaviour or ecology. Under these criteria, allopatric subspecies are a type of evolutionarily significant unit within species in that they show both neutral divergence through the effects of genetic drift and adaptive divergence under natural selection, and provide an historical context for identifying biodiversity units for conservation. Conservation of the adaptedness and adaptability of gene pools, however, may require additional approaches. Recent studies of Australian butterflies exemplify these points. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

The diurnal activity, movement and trypanosome infection rates of Glossina fuscipes fuscipes （Diptera： Glossinidae） in Buvuma Island, Lake Victoria, Uganda

The diurnal activity patterns, trypanosome infection rates and movement of Glossinafuscipesfuscipes （Diptera： Glossinidae） were investigated in Buvuma Island, Lake Victoria, Uganda. Hourly trapping of tsetse flies was undertaken to determine their activity rhythm while a capture-mark-release-recapture method was conducted to assess the movement and dispersal of tsetse flies between lakeshore, hinterland and further inland sites along a transected area. Dissection of tsetse flies was also undertaken to determine the trypanosome infection rates in salivary glands, proboscis and mid-gut. Results indicated a bimodal diurnal activity profile for G. f fuscipes on the Island, both on the lakeshore and in the hinterland. Movement and dispersal of G. f fuscipes tsetse flies occurred between lakeshore, hinterland and further inland sites with a greater tendency of flies to move to the lakeshore. Trypanosome infection rates of 4.32% for Trypasoma vivax and 1.15% for 7. congolense were found in G. f. fuscipes.     

Concerning “long wave length” pigments in algae

Summary Chlorophyll complexes with absorption maxima at 710 m have been observed in certain mutant strains of Chlorella pyrenoidosa. Certain properties of these complexes are described, and some biological activities of far red light are discussed.Dedicated to Professor Dr. E. G. Pringsheim on the occasion of his 80th birthday.     

Green algae in Lake Tanganyika: is morphological variation a response to seasonal changes?

In the framework of a planktological and ecological study in Lake Tanganyika, East Africa (CLIMLAKE, 2001–2005), variations of cell abundance and size were observed in a green alga, Eremosphaera tanganyikae, at two study sites, one in the north basin of the lake (off Kigoma, Tanzania) and the other in the south basin (off Mpulungu, Zambia). Whereas most green algae developed better in the rainy season and in the northern part of the lake, Eremosphaera developed better in the southern basin, in the dry season. It also exhibited large variations in cell abundance and cell size, with maxima in the middle of the dry season, which may be related to increased phosphorus availability. Moreover, increase in cell size (up to 80 μm in length), without notable change in S/V ratio, may provide the alga with resistance to grazing by copepods, which reach maximal abundance during the dry season.     

WHO in retreat: is it losing its influence?

WHO says it has three main functions: to set normative standards; to provide technical advice and assistance on medical matters; and to advocate changes in health policy. During its 46 year history the first two functions have been a constant and uncontroversial backbone through which WHO has earned its reputation for scientific excellence. The third function, advocacy, came to the fore with the launch of Health for All in 1977, after which WHO took a key role in influencing international health policy. WHO''s friends and critics alike now say that the organisation is losing its influence and retreating into its technical and biomedical shell. This article maps the changes in WHO''s approach over the past 46 years and considers whether fears about its loss of influence are justified.     

Can thallus color of red algae be used as an environmental indicator in shallow waters?

Red algae sometimes turn yellow, but few studies have been conducted on the yellowing of subtidal bed-forming species and on the relationship between the color and environmental factors. We examined the seasonal changes in thallus color of macroscopic subtidal red algae and nutrient levels as in shallow waters at two sites: Hirasawa (0 to 3 m in depth) and Okinoshima Island (0 to 6 m in depth), central Pacific coast of Japan from April 2011 to March 2012. Yellowed red algae were found at all depths of the two sites. At Hirasawa, the ratio of yellowed species among the red algae (yellowing ratio, YR) calculated with data on a total of 23 species (3 to 14 species month^?1) was high in months in which nitrate nitrogen (NO₃-N) was low (1.73 to 2.19 μmol L^?1); in months with higher NO₃-N (5.91 to 6.01 μmol L^?1), YR was 0 but exceptionally high in April probably because of the duration of fine days. At Okinoshima Island, YR calculated with data on a total of 40 species (3 to 22 species month^?1) was high from March to July (except May), in which NO₃-N was low (0.93 to 2.16 μmol L^?1), but low from October to February among the months with higher NO₃-N (4.56 to 5.62 μmol L^?1). Totally, YR was negatively correlated with nitrate concentrations and NO₃-N, which supports the possibility to use the value of YR as an indicator of nitrogen level although attention should also be paid to light conditions.     

14. Are the impacts of events in the earth's history discernable in the current distributions of freshwater algae?

Freshwater microalgae, lacking a fossil record, have contributed little to the study of historical biogeography. Some of the innate difficulties are discussed, as well as some of the more hopeful possibilities, if distribution records, morphology and DNA sequence analysis are combined with knowledge of the earth's history. Examples of species within the same family showing quite different distributions are given, along with suggested explanations. These include possible examples of the role played by waterfowl in dissemination of freshwater algae.     

Do volvocal algae form their cultures as autonomous systems?

A low reproducibility of some characteristics in the life cycle of the volvocal algaChlamydomonas geitleri was observed in repeated experiments. The sets of the cultures were very similar in the number of the studied characteristics, but some of them differed significantly in one or several characteristics whereas the others agreed in a whole set. This is documented by the growth in a nitrogenless medium, the formation of zygotes, and their maturation and germination. The results of a small representative set of experiments were treated by an analysis of variance. Some possible explanations are discussed.