Observations on the genus Bosmina in New Zealand

Summary The consideration of specimens from many localities in New Zealand shows that the genus Bosmina is represented by but a single species. This species is maintained to be B. meridionalis by the author. Dorsal incisures are shown to occur on the mucro in juvenile females which suggests the possible identity of this species with B. hagmanni Stingelin. Should the above species prove to be identical the specific name meridionalis is shown to take precedence.

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Résumé L'examen de nombreux specimens pris dans plusieurs endroits de la Nouvelle Zéelande démontre que le genre Bosmina n'est représenté que par l'espèce B. meridionalis. Des incisions dorsales sont visibles sur le mucro chez les jeunes femelles, ce qui suggère l'idée que cette espèce est identique à B. hagmanni Stingelin. Si ces espèces sont vraiment identiques, le nom spécifique B. meridionalis doit avoir la préséance.

     

Observations on normal body temperatures in Vietnamese and Japanese in Vietnam

The observations described in this paper were made during a study of the effects of tropical climate upon Vietnamese and Japanese. We measured rectal and skin temperatures every 10 min for 26 hrs in 6 Vietnamese and 6 Japanese. The experiments have been conducted for 2 hot months, June and July 1999 and 2000 in Hanoi, Vietnam. The ambient temperatures ranged from 33 to 36 degrees C. The results obtained are summarized as follows: 1) Skin temperatures at thigh, forearm and hand during the daytime were significantly higher in the Vietnamese subjects than in the Japanese ones. It would be physiological reactions to warm ambient temperatures, which is advantageous for dissipation of body heat. 2) The average rectal temperature during the daytime is significantly higher in the Vietnamese than in the Japanese, while significantly lower at night. 3) Average range of oscillation of rectal temperature was 1.26 degrees C in the Vietnamese, which was clearly greater than in the Japanese. The higher core temperature, which was actively regulated under warm temperature, seemed of adaptive significance, resulting in the reduction of water consumption like camels in the desert. A greater range of oscillation in tropical Vietnamese people might have ecological significance for efficient acclimatization in the warm environment, suggesting that the setpoint of core temperature could show a greater range of oscillation.     

Correlations between genomic GC levels and optimal growth temperatures: some comments

Regarding the existence of any specific correlation between optimal growth temperature and genomic GC levels, Musto et al. [FEBS Lett. 573 (2004) 73] have recently performed analysis on 20 prokaryotic families and showed that in most of the families there exists a positive correlation between these two parameters. On the basis of these results they claimed that optimal growth temperature is one of the factors that influence genomic GC composition in prokaryotes. In a subsequent article, Marashi and Ghalanbor [Biochem. Biophys. Res. Commun. 325 (2004) 381] have demonstrated that the correlation values change substantially when very few points in some of the families were excluded from the data set of Musto et al. [FEBS Lett. 573 (2004) 73]. But Marashi and Ghalanbor have not provided any reason behind this. The points excluded by Marashi and Ghalanbor are actually the outliers in the data set, which strongly affect the correlation coefficients. But the presence of outliers in large data set hardly had any effect on the correlation values. Marashi and Ghalanbor have excluded points from only those families that have small sample sizes and observed a substantial change in correlation coefficient values. Therefore, we argue that any conclusion drawn for a small sample size having outliers is always questionable. Although Musto's approach is a novel one, but to make any generalization one needs to be careful about the flawlessness in the data set.     

Observations on the superficial sediment temperatures of some lakes in the southeastern United States*

Temperatures of the water column and upper 5 cm of sediment were monitored over a yearly cycle in two South Carolina lakes. Occasional supportive data were also obtained for several lakes in north central Florida. Plans are given for a new type of sediment-interface sampler that is useful in obtaining detailed temperature or chemical profiles extending from the sediment surface upward. The sampler was used in the investigation to demonstrate the thermal microstratigraphy near the mud surface. The deep-water (16 m) temperature for the larger of the two South Carolina lakes changes seasonally from 10·5°C in February to 18·0°C in July. The smaller, shallower (11 m) lake follows an almost identical seasonal cycle but is always 4·0°C cooler because the larger lake receives a heated effluent that has a long-term effect on hypolimnetic temperatures. In both lakes the uppermost sediments are warmer than the overlying water by an average of 0·1 to 1·0°C during the warming period. Heat accretion near the bottom continues but is slower after stratification, probably due to the relatively low temperature (density) differential between water layers in these warm lakes. Cooling in deep water begins long before breakdown of stratification and is apparently caused by cold density currents from the shallows. The coldest water is located in a thin layer just over the sediment. There is evidence from one of the South Carolina lakes and from the Florida lakes that when the density flows begin they at first flow over a warmer water layer that is more dense due to a high electrolyte content derived from the sediment. There is a slight deep water warming in all of the lakes when stratification breaks down. After destratification, the deep water is cooled by turbulence rather than density flows. The surface sediments at this time are consistently warmer than the hypolimnion and remain so through the cooling period. There is strong evidence from one Florida lake that turbulence mixes the upper 3 cm of sediment during the isothermal period. It is concluded that the sediment-water interface of a warm lake will in general experience greater heat flux than that of a comparable cold lake during the periods of temperature maximum and minimum. Conversely, there is likely to be less heat flux during the warming and cooling periods of warm lakes than of cold lakes. Several expected differences in seasonal patterns of temperature and water movement in the deep water of warm and cold lakes are discussed.     

Seed fats of some New Zealand cyperaceae

Seed fats and the constituent fatty acids of Cyperus ustulatus, Desmoschoenus spiralis, Morelotia affinis, 6 species of Gahnia, 2 species of Carex and 25 species of Uncinia, all New Zealand members of the Cyperaceae, are described. Fat content ranges from 2–20%, linoleic acid from 34–78%, oleic acid from 11–48 % and palmitic acid from 5–32%.     

Terpenoids and bibenzyls from some New Zealand liverworts

Four liverworts, Marchantia berteroana, M. foliacea, Plagiochila stephensoniana and Porella elegantula collected in New Zealand were chemically investigated. M. berteroana contains cuparene and (?)-2-hydroxycuparene as the major components. γ-Cadinene is the major component of M. foliacea. 4-Hydroxy-3′-methoxybibenzyl is a chemical marker for P. stephensoniana which belongs to the non-pungent type of Plagiochila species. P. elegantula synthesizes perrottetianal and belongs to the non-pungent type of Porella species.     

Observations on the haematology and oxygen transport of the New Zealand fur seal,Arctocephalus forsteri

Abstract

Red cell count, haemoglobin concentration, haematocrit, mean cell volume, and mean cell haemoglobin concentration were recorded for the fur seal Arctocephalus forsteri (Lesson). The data did not indicate haematological adaptations for deep diving nor for extended periods of submergence. Two distinct haemoglobin types were isolated from the red cells by electrophoresis. The oxygen affinity of the blood was low as measured by half-saturation values (p50) of 42.3 mm Hg at pH 7.1 and 26.2 mm Hg at pH 7.4 and 37°c. The low oxygen affinity was mediated by erythrocytic 2,3-diphosphoglycerate, and on this basis a high turnover of oxygen to the tissues is postulated. The role of the blood in oxygen transport appears to be suited for feeding near the surface rather than by deep diving.     

Observations on granulocyte peroxidase in New Zealand freshwater eels, Anguilla species

Peroxidase activity in the granulocytes of eels was investigated using o-tolidine, paraphenylene-diamine-pyrocatechol, and 4-chloro-l-naphthol as substrates, and cyanide, azide and aminotriazole as inhibitors. Most circulating neutrophils of Anguilla australis Richardson, 1848 and A. dieffenbachii Gray. 1842 showed no peroxidase activity at pH 7.6 and pH 9.0, but a few neutrophils, thought to be mature, were positive. Another granulocyte in the anterior kidney, spleen, parasitized gill tissue and, rarely, the blood contained a cyanide-resistant, azide-inhibited, peroxidase and was tentatively identified as the eosinophil. Neutrophils of A. anguilla (L.) showed granular peroxidase activity which was inhibited by cyanide. The eosinophil was not observed.
Absence of peroxidase from most circulating neutrophils in A. anguilla and A. dieffenbachii , and its pattern in the neutrophil precursors and mature neutrophils of A. anguilla , may be due to two morphologically indistinguishable granule types. Primary peroxidase-negative granules occur in precursors and immature neutrophils and secondary peroxidase-positive granules in mature neutrophils of all three eels. Circulating neutrophils in New Zealand eels seldom mature and are theretore peroxidase-negative, whereas A. anguilla neutrophils are mature and are usually peroxidase-positive.
Impairment of microbicidal activity in neutrophils lacking peroxidase is discussed.     

Nitrogen concentration and mimicry in some New Zealand mistletoes

Summary The nitrogen concentration in photosynthetic organs of 41 pairs of mistletoes and their respective hosts was compared and found to be higher (in relation to that of their hosts) in cryptic mistletoes and lower in non-cryptic mistletoes. This supports the hypothesis that crypsis may have evolved as a mechanism for avoiding predation by vertebrate herbivores. There were no consistent differences between the nitrogen concentrations of hosts and mistletoes in trees and larger-leaved shrubs (whether native or introduced). The largest differences between mistletoes and their hosts were found on small-leaved divaricate shrubs (Coprosma ssp., Melicope simplex) where the nitrogen concentrations in cryptic mistletoes (Korthalsella spp.) were significantly higher than in their hosts, but significantly lower in prominent mistletoes (Loranthus micranthus, Tupeia antarctica) which apparently advertise their unpalatability. If crypsis in New Zealand mistletoes evolved as a protection against herbivory, then it must have evolved in the absence of mammalian herbivores, and the appropriate selection pressures could have been provided only by moas, extinct ratite birds. Otherwise, alternative explanations, such as differing relationships between water use and nitrogen uptake, must be sought for the observed associations of nitrogen concentration and cryptic mimicry in New Zealand mistletoes.