THE TAPETUM FIBROSUM IN THE EYES OF TWO SMALL WHALES

The pygmy sperm whale ( Kogia breviceps ) and the bottlenose dolphin ( Tursiops truncatus ) are equipped with a tapetum fibrosum and, with other Cetacea, are the only carnivores known to possess this typically ungulate tapetal type. Tapeta from two regions of a retina, each with a different spectral reflectance (blue and green), were found to have significantly different fibrillar diameters and inter-fibrillar spacing. When the measured values are applied to a dielectric reflector model, the predicted wavelengths agree with the observed reflectance of the flat-mounted tapeta. The spatial properties of the fibrils change progressively from the tapetal origin in the fibroblast layer to the pigment epithelium, suggesting that different wavelengths may be reflected systematically with tapetal depth. The very large number of reflecting layers characterizing these tapeta, relative to those of other carnivores, may provide for increased spectral purity and efficiency.     

APPARENT BOTTOM FEEDING BY HUMPBACK WHALES ON STELLWAGEN BANK

Humpback whales, Megaptera novaeangliae , on Stellwagen Bank off eastern Massachusetts, U.S.A., apparently bottom feed on northern sand lance, Ammodytes dubius . The feeding behavior is characterized by the whales brushing the bottom in depths of less than 40 m, causing sand lance burrowed in the bottom to be flushed up into the water column. The greatest densities of sand lance were in beds of shells and shell debris, termed "shell hash." The brushing against or along the bottom, particularly in these shell hash areas, caused the humpbacks to acquire abrasions and wounding, sometimes rather extensive, of the lateral lower jaw, and lateral and dorso-lateral upper jaw, here termed "jaw scuffing." Scuffing of the dorsal fin and fluke edges was also common and may be at least partially related to this feeding behavior. Both mature and immature, and male and female, humpbacks exhibited jaw scuffing. The bottom-feeding behavior was not exclusive, as jaw-scuffed individuals were also observed to use other feeding behaviors. In recent years (1991-1993), however, bottom feeding appears to have become relatively more common, particularly among young animals. Overall, in the Stellwagen Bank area between 1979 and 1993, a majority of the population engaged in, or had engaged in, bottom feeding and the associated prey flushing.     

SPERM WHALES TAGGED WITH TRANSPONDERS AND TRACKED UNDERWATER BY SONAR

Abstract: Two sperm whales tagged with acoustic transponder tags were tracked by sonar during a cruise from 16 to 30 October 1991 in the southeast Caribbean west of Dominica Island. The whales dove to depths of 400–600 m and more, including a dive to 1,185 m and one possibly to 2,000 m. They were tracked for periods of 3–14 h, over distances of 8.5–40 km. The tagged whales were found together four and eight days after tagging, and were tracked simultaneously for 13 h, over 31 km. Whale movements on different days at the surface averaged from 0.68 to 0.82 m/set, with dive descent rates from 0.82 to 1.13 m/set, ascent rates from 0.74 to 1.16 m/set, and horizontal movement during dives from 0.76 to 1.29 m/set. Dives lasted from 18 min to 1 h and 13 min, averaging 33 and 41 min on different days. Every track ended when tag signals became obscured at night by dense biological scatterers concentrated in offshore areas where the whales were diving. Both tagged whales appear to have been males of 15 and 11m, each dominant in different groups; but when together the larger whale was dominant, as evidenced by chases and agonistic vocalizations. The whales did not appear to react to the tags or to the sounds associated with tracking (30, 32, and 36 kHz).     

CYTOCHEMICAL LOCALIZATION OF TWO GLYCOLYTIC DEHYDROGENASES IN WHITE SKELETAL MUSCLE

The cytochemical localization, by conventional methods, of lactate and glyceraldehyde-3-phosphate dehydrogenases is limited, firstly, by the solubility of these enzymes in aqueous media and, secondly, by the dependence of the final electron flow from reduced nicotinamide-adenine dinucleotide (NADH) to the tetrazolium on tissue diaphorase activity: localization is therefore that of the diaphorase, which in rabbit adductor magnus is mitochondrial. NADH has been found to have great affinity to bind in the sarcoplasmic reticulum, and, therefore, if it is generated freely in the incubation media containing 2,2',5,5'-tetra-p-nitrophenyl-3,3'-(3,3'-dimethoxy-4,4'-phenylene)-ditetrazolium chloride (TNBT) and N-methyl phenazonium methyl sulfate (PMS), it can bind there and cause a false staining. Since such a production of NADH can readily occur in the incubation media for glycolytic dehydrogenases due to diffusion of these soluble enzymes from tissue sections, the prevention of enzyme solubilization is extremely important. Fixation in formaldehyde prevented such enzyme diffusion, while at the same time sufficient activity persisted to allow for adequate staining. The incubation media contained PMS, so that the staining system was largely independent of tissue diaphorase activity. Application of these methods to adductor magnus of rabbit revealed by light microscopy, for both enzymes, a fine network which was shown by electron microscopy to represent staining of the sarcoplasmic reticulum. Mitochondria also reacted. These findings add further support for the notion that the sarcoplasmic reticulum is probably involved in glycolytic activity.     

ESTIMATION OF PREY DENSITIES REQUIRED BY WESTERN NORTH ATLANTIC RIGHT WHALES

The apparent lack of significant recovery of western North Atlantic right whale populations may be related to the availability of prey in exploitable densities. We have attempted to estimate the concentration of zooplankton required by right whales to obtain a net energetic benefit over the long term, using estimated values for body weight, metabolic rate, assimilation efficiency, time spent feeding, mouth size and swimming speed. The estimated range of required energy densities is 7.57 to 2,394 kcal m⁻³ (3.17 × 10⁴ to 1.00 × 10⁷ joule m⁻³). These values are from one to more than three orders of magnitude greater than the densest concentration sampled in the vicinity of right whale aggregations in the Great South Channel. Right whales must seek out and exploit extremely dense patches of prey organisms in order to feed efficiently. The presence of such dense patches of zooplankton is likely to be a primary characteristic of spring, summer and fall right whale habitats.     

蛋清破花粉壁的研究

花粉含有人类所需的各种营养成分,具有较高的营养和保健价值,因为花粉外壁含有油胡萝卜素和类胡萝卜素酯组成的物理,化学及酶稳定的花粉素,故影响对花粉的深加工,本文报道经长期研究的蛋清破花粉壁的方法,以微球菌（Ｍ．ｌｙ８ｓｏｄｅｉｋｔｉｃｕｓ）为对照,发现花粉外壁含有肽聚糖,不但为研究花粉破壁进行了提供了依据,而且能用于多种花粉产品的生产。     

HIGH PERFORMANCE TURNING CAPABILITIES DURING FORAGING BY BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)

Large predators should have difficulty catching small prey because small animals demonstrate greater maneuverability and agility compared to large animals. The ability of a predator to capture small prey indicates locomotor strategies to compensate for inequities in maneuverability. Bottlenose dolphins ( Tursiops truncatus ) in Sarasota Bay, Florida feed on fish at least one order of magnitude smaller than themselves. To examine the locomotor strategies involved in prey capture, the foraging movements of these dolphins were videotaped from overhead using a remotely-controlled camera suspended from a helium-filled aerostat, which was tethered to an observation vessel. Dolphins were observed to rapidly maneuver during chases of fish in open water or around patches of rooted vegetation. Video analysis of the chase sequences indicated that the dolphins could move the rostrum through small radius turns with a mean value of 0.20 body lengths and with a minimum value of 0.08 body lengths. Mean rate of turn was 561.6°/sec with a maximum rate measured at 1,372.0°/sec. High turning rates with small turning radii were primarily the result of maneuvers in which the dolphin rolled 90° and rapidly flexed its body ventrally. The ability of dolphins to change body orientation in multiple rotational axes provides a mechanism to reduce turning radius and increase turning rate to catch small, elusive prey.     

辐照白酒对其理化指标影响的研究

利用（６０）Ｃｏ─γ射线辐照市售散装白洒（６０°）,处理剂量为０．８ｋＧｙ、２．０ｋＧｙ、４．０ｋＧｙ,剂量率为３．３３Ｇｙ／ｍｉｎ,在贮存不同时间后,检验其理化及感官指标。结果表明,经γ射线辐照的白洒,总酸、总酯等有益成分均有不同程度增加,其感官指标也比对照组好,尤其以辐照剂量２．０ｋＧｙ的处理组最佳,且辐照后贮存一定时间,其陈化效果更好。