The ecology of marine exploitation in prehistoric Hawaii

Archaeological evidence for prehistoric strategies of marine exploitation in Oceania may be profitably analyzed from an ecological perspective, in which individual sites and assemblages are viewed in the context of adaptation to local environmental constraints. This perspective is illustrated through the contrastive analysis of environment, technology, and faunal remains at three prehistoric Hawaiian sites. Differing strategies of marine exploitation evidenced for each site are shown to reflect local marine environmental conditions. An ecological approach shows greater promise for an understanding of prehistoric adaptation to marine environment than the typological analyses current in much archaeological work on fishing.     

Biochemical characterization ofSerratia liquefaciens sensu stricto,Serratia proteamaculans,andSerratia grimesii sp. nov.

Seven biochemical groups were found among strains previously labeledSerratia liquefaciens (groups C1ab, C1c, C1d, EB, RB, RQ, and Adc). Comparison of biochemical data with DNA relatedness data allowed the definition (or redefinition) of threeSerratia species:Serratia liquefaciens sensu stricto (group C1ab),Serratia proteamaculans (groups C1c, EB, RB, and RQ), andSerratia grimesii sp. nov. (groups C1d and Adc). Biochemical group RQ, which is genomically related toS. proteamaculans at the borderline of species level, is proposed as a new subspecies ofS. proteamaculans (Serratia proteamaculans subsp.quinovora). Group Adc (3 strains) is also ambiguously related toS. grimesii, but no other proposal is made pending additional studies. The type strains of the newly named taxa,S. grimesii andS. proteamaculans subsp.quinovora, are respectively ATCC 14460 and strain 4364 (= CIP 8195 = ATCC 33765).     

Patch-clamp study of isolated taste receptor cells of the frog

Summary Taste discs were dissected from the tongue ofR. ridibunda and their cells dissociated by a collagenase/low Ca/mechanical agitation protocol. The resulting cell suspension contained globular epithelial cells and, in smaller number, taste receptor cells. These were identified by staining properties and by their preserved apical process, the tip of which often remained attached to an epithelial (associated) cell. When the patch pipette contained 110mm KCl and the cells were superfused with NaCl Ringer's during whole-cell recording, the mean zero-current potential of 22 taste receptor cells was –65.2 mV and the slope resistance 150 to 750 M. Pulse-depolarization from a holding voltage of –80 mV activated a transient TTX-blockable inward Na current. Activation became noticeable at –25 mV and was half-maximal at –8 mV. Steady-state inactivation was half-maximal at –67 mV and complete at –50 mV. Peak Na current averaged –0.5 nA/cell. The Ca-ionophore A23187 shifted the activation and inactivation curve to more negative voltages. Similar shifts occurred when the pipette Ca was raised. External Ni (5mm) shifted the activation curve towards positive voltages by 10 mV. Pulse depolarization also activated outward K currents. Activation was slower than that of Na current and inactivation slower still. External TEA (7.5mm) and 4-aminopyridine (1mm) did not block, but 5mm Ba blocked the K currents. K-tail currents were seen on termination of depolarizing voltage pulses. A23187 shifted theI _K(V)-curve to more negative voltages. Action potentials were recorded when passing pulses of depolarizing outward current. Of the frog gustatory stimulants, 10mm Ca caused a reversible 5-to 10-mV depolarization in the current-clamp mode. Quinine (0.1mm, bitter) produced a reversible depolarization accompanied by a full block of Na current and, with slower time-course, a partial block of K currents. Cyclic AMP (5mm in the external solution or 0.5 m in the pipette) caused reversible depolarization (to –40 to –20 mV) due to partial blockage of K currents, but only if ATP was added to the pipette solution. Similar responses were elicited by stimulating the adenylate cyclase with forskolin. Blockage of cAMP-phosphodiesterase enhanced the response to cAMP. These results suggest that cAMP may be one of the cytosolic messengers in taste receptor cells. Replacement of ATP by AMP-PNP in the pipette abolished the depolarizing response to cAMP. Inclusion of ATP--S in the pipette caused slow depolarization to –40 to –20 mV, due to partial blockage of K currents. Subsequently, cAMP was without effect. The remaining K currents were blockable by Ba. These results suggest that cAMP initiates phosphorylation of one set of K channels to a nonconducting conformation.     

Seasonal and size-related changes in the food of the short-finned eel,Anguilla australis in Lake Ellesmere,Canterbury, New Zealand

Synopsis An approximately monthly sampling programme in Lake Ellesmere, Canterbury, New Zealand, from January 1974 to April 1976 yielded 487 eels. The stomachs were fixed in 10% neutralised formalin and the contents examined. Preliminary analysis indicated that the mollusc Potamopyrgus antipodarum, the isopod Austridotea annectens, the mysid Tenagomysis chiltoni, the amphipod Paracalliope fluviatilis, the midge larva Chironomus zealandicus and the teleosts Retropinna retropinna, Galaxias maculatus and Gobiomorphus cotidianus together made up the bulk of the diet. The pre-ingested dry weight (i.e. the reconstructed weight) of the most important of these prey species was obtained by relating the length of a digestion resistant part to actual dry weight in field collected specimens. Regression equations for this relationship in each season enabled the reconstructed dry weight of each stomach item to be calculated. In some instances reconstructed weight was less than the actual digested dry weight of the prey specimen. In every case the larger value was used. This method is referred to as Combination Dry Weight (CDW) and is believed to be new. These data, used in conjunction with the energy content of the species concerned, enabled the caloric dietary contribution of each prey species to be determined. Comparison of relative contribution to eel diet between CDW and energy values calculated from CDW and bomb calorimetry revealed large differences. Marked variations in diet between ⩽40 cm, 40.1–50 cm, and>50.1 cm size classes were also shown. Eels ≤40 cm feed primarily on invertebrates and become progressively more piscivorous as they grow. Eels >50.1 cm are almost entirely piscivorous. Seasonal differences in diet also exist within each size class examined.     

Enhancement of Butanol Formation by Clostridium acetobutylicum in the Presence of Decanol-Oleyl Alcohol Mixed Extractants

Extractive fermentation has been proposed to enhance the productivity of fermentations that are end product inhibited. Unfortunately, good extractants for butanol, such as decanol, are toxic to Clostridium acetobutylicum. The use of mixed extractants, namely, mixtures of toxic and nontoxic coextractants, was proposed to circumvent this toxicity. Decanol appeared to inhibit butanol formation by C. acetobutylicum when present in a mixed extractant that also contained oleyl alcohol. However, maintenance of the pH at 4.5 alleviated the inhibition of butanol production and the consumption of butyrate during solventogenesis. A mixed extractant that contained 20% decanol in oleyl alcohol enhanced butanol formation by 72% under pH-controlled conditions. The production of acetone and acetoin was also increased, even though these two products were not extractable. The enhancement of butanol formation was not limited by the toxicity of decanol. Supplementation of glucose and butyrate in the extractive fermentation yielded a 47% increase in butanol. The enhancement of butanol formation appeared to be dependent on the presence of dissolved decanol in the broth but was not observed unless an organic phase was present to extract butanol. A mechanism for the effects of decanol on product formation is proposed.