EXPERIMENTAL PRODUCTION OF GIGANTISM BY FEEDING THE ANTERIOR LOBE OF THE HYPOPHYSIS

1. Metamorphosed salamanders of the species Ambystoma opacum and Ambystoma tigrinum were fed on a pure diet of the anterior lobe of the hypophysis of cattle; the controls were fed on an abundant diet of earthworms. 2. The rate of growth of the animals fed on the anterior lobe of the hypophysis was greatly increased over the rate of growth of normal animals. 3. Growth of the animals fed on anterior lobe did not cease after they had reached the normal "maximum" size of the species, and experimental giants were produced. 4. The largest animal of the species Ambystoma opacum fed on anterior lobe of the hypophysis was 19 mm. larger than the largest normal animal of this species known to the writer; the largest animal of the species Ambystoma tigrinum fed on anterior lobe is at present about 28 mm. larger than the largest normal animal of the eastern race of this species known to the writer.     

Effect of group size and maize silage dietary levels on behaviour,health, carcass and meat quality of Mediterranean buffaloes

The effects of different dietary levels of maize silage (10% v. 36% DM) and group size (7 v. 14 animals) were assessed on growth performance and in vivo digestibility of 28 male fattening buffaloes. In addition, the effects of diet on meat quality and group size on behaviour and immune response were separately evaluated. Animals were weighed and assigned to three groups. The high silage – low size group (HL) was fed a total mixed ration (TMR) containing 36% DM of maize silage and consisted of seven animals (age 12.7±2.6 months; BW 382.2±67.7 kg at the start of the study). The low silage – low size group (LL) was fed a TMR containing 10% DM of maize silage and consisted of seven animals (age 13.0±2.7 months; BW 389.4±72.3 kg). The high silage – high size group (HH) was fed the 36% maize silage DM diet and consisted of 14 animals (age 13.9±3.25 months; BW 416.5±73.9 kg). Total space allowance (3.2 indoor+3.2 outdoor m²/animal) was kept constant in the three groups, as well as the ratio of animals to drinkers (seven animals per water bowl) and the manger space (70 cm per animal). Growth performance, carcass characteristics and digestibility were influenced neither by dietary treatment nor by group size, even if the group fed 36% maize silage diet showed a higher fibre digestibility. No effect of diet was found on meat quality. Group size did not affect the behavioural activities with the exception of drinking (1.04±0.35% v. 2.60±0.35%; P<0.01 for groups HL and HH, respectively) and vigilance (2.58±0.46% v. 1.20±0.46%; P<0.05 for groups HL and HH, respectively). Immune responses were not affected by group size.     

Eisenia arborea J.E. Areschoug as abalone diet on an IMTA farm in Baja California,México

Recent progress in the domestication of Eisenia arborea lead us to test this species as an alternative to feed red abalone (Haliotis rufescens) instead of Macrocystis pyrifera, which is the main seaweed used to feed farmed abalone in Baja California, Mexico. E. arborea is the kelp with the largest and most southerly latitudinal distribution on the North Pacific East Coast capable of growing at higher temperatures and in relatively low nutrient conditions. The availability of M. pyrifera is frequently uncertain because it is strongly affected by El Niño events. In order to test E. arborea as a diet for farmed abalone, animals of two different sizes (6 and 2 cm) were fed separately for 12 months with these two seaweed species. The abalones were cultured in cages in an integrated multi-trophic aquaculture farm within San Quintín Bay, Baja California, Mexico. Seaweed was collected for chemical analysis, and every 3 months, animals were measured and weighed to estimate growth. Small size abalone doubled their size on both diets, with an average increase in length of 2.2 mm month^?1. No significant differences were observed between both treatments. Large abalone fed with M. pyrifera had slighter higher growth rates compared to those fed with E. arborea (0.57 and 0.50 % day^?1, respectively). Although M. pyrifera appeared to be a better diet for large animals, the growth rates obtained with E. arborea and the fact that this species could be cultivated in warmer conditions makes this seaweed species a good candidate to feed farmed abalone.     

THE SECRETION OF DIGESTIVE ENZYMES AND CAECAL SIZE ARE DETERMINED BY DIETARY PROTEIN IN THE CRICKET Gryllus bimaculatus

In Gryllus bimaculatus, the size of the caecum decreases in the latter half of each instar to a stable minimal size with a steady minimal rate of digestive enzyme secretion until feeding resumes after ecdysis. The higher the percent protein in the newly ingested food, the faster and larger the caecum grows, and as a consequent the higher the secretion rate of trypsin and amylase. When hard boiled eggs (40% protein) are eaten the caecum is 2× larger, the trypsin secretion is almost 3× greater, and amylase 2.5× greater then when fed the same amount of apples (1.5% protein). Only dietary protein increases amylase secretion, whereas dietary carbohydrates have no effect on amylase secretion. The minimal caecal size and secretion rate must be supported by utilization of hemolymph amino acids, but the growth of the caecum and increasing enzymes secretions after the molt depend upon an amino acid source in the lumen. This simple regulation of digestive enzyme secretion is ideal for animals that must stop feeding in order to molt. This basic control system does not preclude additional regulation mechanisms, such as prandal, which is also indicated for G. bimaculatus, or even paramonal regulation.     

THE ISSUE OF ANTIBIOTIC USE IN THE LIVESTOCK INDUSTRY: WHAT HAVE WE LEARNED?

It is generally believed that it is better to use medicinal products as therapeutics to treat disease situations, using high doses for short periods of time, rather than as prophylactics, when low doses are fed continuously. It is therefore the continuous use of low levels of medicinal products as growth promoters in farm animals that has been brought into question, as it is thought that this may increase the risk of development of bacterial resistance to antibiotics used as therapeutic drugs to treat disease in humans.     

Cranial growth in Saimiri sciureus (Cebidae) and its alteration by nutritional factors: A longitudinal study

Ten male Saimiri sciureus boliviensis (Cebidae), born at the Centro Argentino de Primates (CAPRIM), were grown in captivity. At weaning (6 months old), five individuals were fed ad libitum on a 20% protein diet (controls). The other five animals were fed ad libitum on a 5% protein diet (malnourished). Animals were radiographed monthly. The length, width, and height of the anterior, middle, and posterior components of the neurocranium, and those of the masticatory, respiratory, and optic components of the face were measured. A pattern of high growth rate was observed in both the three facial and the middle neural components. The anterior and posterior neural components showed a pattern of low rate of growth. The growth behavior of each variable was also different. Lengths grew more than widths and heights in the facial components, whereas widths grew more than heights and lengths in the neurocranium. Malnutrition delayed growth in size and altered the normal shape changes. High-patterned variables, such as masticatory and respiratory lengths, and the anterior and middle neural widths were particularly affected. The masticatory and the middle neural components underwent the greatest growth arrest. The optic and the respiratory components suffered a mild effect. The anterior and the posterior neural components were affected to a lesser degree. Am J Phys Anthropol 102:545–554, 1997. © 1997 Wiley-Liss, Inc.     

Prey-induced changes to a predator's behaviour and morphology: Implications for shell-claw covariance in the northwest Atlantic

Whereas many plasticity studies demonstrate the importance of inducible defences among prey, far fewer investigate the potential role of inducible offences among predators. Here we ask if natural differences in a snail's shell hardness can induce developmental changes to a predatory crab's claw size. To do this, we fed Littorina obtusata snails from either thick- or thin-shelled populations to captive European green crabs Carcinus maenas. The crabs' shell-breaking behaviour dominated among those fed thin-shelled snails, whereas crabs fed thick-shelled snails mostly winkled flesh through the shell opening without damaging the shell itself (a.k.a. aperture-probing behaviour). Significantly, the size of crab crusher claws grew in proportion to the frequency of shell-crushing behaviour and, for a same shell-crushing frequency, crabs fed thick-shelled snails grew larger crusher claws than those fed thin-shelled snails after two experimental moults. Diet and behaviour had no effect on the growth of the smaller cutter claws of same individuals, providing good evidence that allometric changes to crusher claws were indeed a result of differential use while feeding. Findings indicate that both predation habits and claw sizes are affected by green crabs' diet, supporting the hypothesis that prey-induced phenotypic plasticity contributes to earlier accounts of shell-claw covariance between this predator and its Littorina prey in the wild.     

白地霉长期饲喂大鼠对食管和前胃影响的组织形态观察

在肿瘤病因研究中,霉菌与肿瘤发生的关系,近十多年来愈来愈受到人们的重视,目前已知约有10种真菌的毒素有致癌作用,能诱发出大、小鼠不同器官的肿瘤,如黄曲霉毒素与肝癌的关系为人们所共知(徐达道1973;孟昭赫,1973;严瑞琪,1978;Lancaster,1961;Schoental,1961)。自国内有关白地霉(Geotrichum candidum Link)致瘤与促癌作用实验研究等文章发表以来(杨简、高进,1980),引起了工、农、医有关部门极大的关注。早在1958年上海即利用废泔脚水做原料,发酵培养白地霉制咸蛋白质的补充食料“人造肉精”,初步试用饲养猪、鸡作为蛋白质饲料,更进而利用白地霉菌体提取核酸及     

LYSOSOME FUNCTION IN THE REGULATION OF THE SECRETORY PROCESS IN CELLS OF THE ANTERIOR PITUITARY GLAND

The nature and content of lytic bodies and the localization of acid phosphatase (AcPase) activity were investigated in mammotrophic hormone-producing cells (MT) from rat anterior pituitary glands. MT were examined from lactating rats in which secretion of MTH¹ was high and from postlactating rats in which MTH secretion was suppressed by removing the suckling young. MT from lactating animals contained abundant stacks of rough-surfaced ER, a large Golgi complex with many forming secretory granules, and a few lytic bodies, primarily multivesicular bodies and dense bodies. MT from postlactating animals, sacrificed at selected intervals up to 96 hr after separation from their suckling young, showed (a) progressive involution of the protein synthetic apparatus with sequestration of ER and ribosomes in autophagic vacuoles, and (b) incorporation of secretory granules into multivesicular and dense bodies. The content of mature granules typically was incorporated into dense bodies whereas that of immature granules found its way preferentially into multivesicular bodies. The secretory granules and cytoplasmic constituents segregated within lytic bodies were progressively degraded over a period of 24 to 72 hr to yield a common residual body, the vacuolated dense body. In MT from lactating animals, AcPase reaction product was found in lytic bodies, and in several other sites not usually considered to be lysosomal in nature, i.e., inner Golgi cisterna and associated vesicles, and around most of the immature, and some of the mature secretory granules. In MT from postlactating animals, AcPase was concentrated in lytic bodies; reaction product and incorporated secretory granules were frequently recognizable within the same multivesicular or dense body which could therefore be identified as "autolysosomes" connected with the digestion of endogenous materials. Several possible explanations for the occurrence of AcPase in nonlysosomal sites are discussed. From the findings it is concluded that, in secretory cells, lysosomes function in the regulation of the secretory process by providing a mechanism which takes care of overproduction of secretory products.     

Catch-up growth in Japanese quail (Coturnix Japonica): relationships with food intake, metabolic rate and sex

The effects of early environmental conditions can profoundly affect individual development and adult phenotype. In birds, limiting resources can affect growth as nestlings, but also fitness and survival as adults. Following periods of food restriction, individuals may accelerate development, undergoing a period of rapid “catch-up” growth, in an attempt to reach the appropriate size at adulthood. Previous studies of altricial birds have shown that catch-up growth can have negative consequences in adulthood, although this has not been explored in species with different developmental strategies. Here, we investigated the effects of resource limitation and the subsequent period of catch-up growth, on the morphological and metabolic phenotype of adult Japanese quail (Coturnix japonica), a species with a precocial developmental strategy. Because males and females differ in adult body size, we also test whether food restriction had sex-specific effects. Birds that underwent food restriction early in development had muscles of similar size and functional maturity, but lower adult body mass than controls. There was no evidence of sex-specific sensitivity of food restriction on adult body mass; however, there was evidence for body size. Females fed ad lib were larger than males fed ad lib, while females subjected to food restriction were of similar size to males. Adults that had previously experienced food restriction did not have an elevated metabolic rate, suggesting that in contrast to altricial nestlings, there was no metabolic carry-over effect of catch-up growth into adulthood. While Japanese quail can undergo accelerated growth after re-feeding, timing of food restriction may be important to adult size, particularly in females. However, greater developmental flexibility compared to altricial birds may contribute to the lack of metabolic carryover effects at adulthood.     

ELECTRON MICROSCOPY OF THE PACINIAN CORPUSCLE

The Pacinian corpuscle has a framework of cytoplasmic lamellae arranged concentrically in the outer zone, and bilaterally in the core. Between these is an intermediate growth zone. The inner core shows an unexpected complexity in that its component lamellae are arranged in two symmetrical groups of nested cytoplasmic sheets. Longitudinal tissue spaces form clefts separating the two groups. The perikarya of the core lamellae lie in or near the intermediate growth zone, and send arms into the clefts. The arms then branch and terminate as lamellae which interdigitate with those of neighboring cells. The single nerve fiber loses its myelin sheath just before it reaches the inner core but retains its Schwann cell cytoplasmic covering for a short additional distance. The Schwann sheath is not continuous with the lamellae of the inner core. Inside the core the fiber contains a striking circumferential palisade of radially disposed mitochondria. The fiber does not arborize. Vascular capillaries penetrate the hilar region of the corpuscle only as far as the myelinated sheath of the nerve, and they have not been seen elsewhere in the corpuscle. There is direct continuity between the clefts of the core and tissue spaces in the vicinity of the capillaries. It is likely that this provides a route whereby metabolites reach the active nerve ending, as well as the cells of the growth zone. The outer zone consists of at least 30 flattened concentric cytoplasmic lamellae separated from one another by relatively wide fluid-filled spaces. Collagenous fibrils are present, particularly on the outer surface of lamellae, and tend to be oriented circularly. The girdle of proliferating cells constituting the growth zone, which is prominent in corpuscles from young animals, is the layer from which the outer lamellae are derived. Osmotic forces probably elevate the lamellae, and maintain turgor pressure.     

THE NATURE OF THE FACTORS WHICH DETERMINE THE SEQUENCE OF GROWTH-CYCLES AND ITS RELATIONSHIP TO THE DIFFERENTIATION OF TISSUES

1. It has previously been shown by the author and many others that growth, in animals and plants, is an autocatalysed process. In animals it is usual to find that growth occurs in several superimposed autocatalytic cycles. In many cases, in plants and animals, especially if the cycle is one which occupies a large proportion of the growing period, it is found that the velocity-constant of the autocatalysed monomolecular formula falls off as growth proceeds, at first rapidly and later more slowly. 2. It has previously been shown by the author that the fall of the velocity-constant of growth, in the white mouse, is directly proportional to the fall of the nucleo-cytoplasmic ratio, determined by the chemical method of Le Breton and Schaeffer. If we assume this relationship to be generally applicable to the growth of animals and plants, then the following additional conclusions may be deduced, without calling in the aid of any other assumption:— 3. The increase of cytoplasm in any given cycle of growth is proportional to the concurrent increase of nuclear material. 4. The growth of cytoplasm takes place in accordance with a monomolecular formula in which the velocity-constant varies directly as the mass of the nucleus. If we superadd to these facts and deductions the hypothesis that each growth-cycle represents the growth of a separate group of cells within the animal, then the additional conclusions follow:— 5. That the cells which participate in the growth composing any cycle have initially lower nucleo-cytoplasmic ratios than the cells which participated in the preceding cycles. 6. That cells of large nucleo-cytoplasmic ratios in a multicellular animal inhibit the growth of cells which possess smaller ratios. 7. These conclusions collectively imply that the nucleus plays a predominant role in determining the development of the cell in which it resides.     

THE INFLUENCE OF THE MODE OF NUTRITION ON THE DIGESTIVE SYSTEM OF OCHROMONAS MALHAMENSIS

The intracellular distribution and level of acid hydrolases in Ochromonas malhamensis were studied in cells grown osmotrophically in a defined medium, in a carbon-free starvation medium, and during phagotrophy in each of these media. By cytochemical techniques, little enzymic reaction product was observed in the vacuoles of osmotrophic cells grown in the defined medium. Starved cells, however, contained autophagic vacuoles and cannibalized other Ochromonas cells. Dense enzymic reaction product was observed in the digestive vacuoles and in the Golgi cisternae of these starved cells. Moreover, starved cells and cells grown in a nutritionally complete medium ingested Escherichia coli which appeared in digestive vacuoles containing enzymic reaction product. Biochemical assays for lysosomal acid phosphatase (E.C. 3.1.3.2 orthophosphoric monoester phosphohydrolase) and acid ribonuclease (E.C. 2.7.7.16 ribonucleate nucleotido-2'-transferase) were done on Ochromonas cultures in the same experimental treatments and under identical assay conditions as the cytochemical study. During starvation, the acid hydrolase specific activities were consistently twice those found in cells grown in an osmotrophic complete medium. Ochromonas fed E. coli showed no increase in acid hydrolase specific activity as compared to controls not fed E. coli. The latency of lysosomal acid hydrolases in cells fixed with glutaraldehyde was reduced, suggesting that this fixative increases lysosomal membrane permeability and may release enzymes or their reaction products into the cytoplasmic matrix during cytochemical analysis. This could explain the cytoplasmic staining artifact sometimes observed with glutaraldehyde-fixed cells when studied by the Gomori technique. This study confirms that Ochromonas malhamensis, a phytoflagellate, does produce digestive vacuoles and can ingest bacteria, thereby fulfilling its role as a heterotroph in an aquatic food chain. When Ochromonas is grown in a nutritionally complete osmotrophic medium, phagocytosis causes appearance of acid hydrolases in the digestive vacuoles, whereas the total activity of the enzymes remains unchanged. An organic carbon-free medium strongly stimulates acid hydrolaes activity and causes these enzymes to appear in the digestive vacuoles whether phagocytosis occurs or not.     

ASPECTS OF THE GROWTH AND REPRODUCTION OF LABEO CAPENSIS IN THE CALEDON RIVER

SUMMARY

The scale studies indicate that the annulus is a reliable year mark. A linear relationship exists between anterior scale radius and body length so that back-calculations of length were possible. Males and females had a similar growth rate. The growth rate is similar to that found by Mulder (1973) for L. capensis in the Vaal River. Fish under 35 centimetres in length had a sex ratio of 1:1, but in larger fish, only 16 per cent were males. Males reach sexual maturity at a length of 15 to 25 centimetres and females at a length of 20 to 25 centimetres. The spawning season extends from September to March with a peak in November. Fecundity increased with an increase in length from 12 664 for a fish of 22.8 centimetres to 106 286 for a fish of 34.8 centimetres.

The results are basically similar to those found by Mulder (1973) in the Vaal River except for fecundity and length at sexual maturity.     

Dietary influence on the biology and metabolism of Isotoma viridis (Collembola)

(1) Two groups of individually cultured Isotoma viridis were studied. They were given a diet of Tetramin fishfood and Pleurococcus algae respectively, in order to monitor individual changes in oxygen uptake during culture. (2) Growth rate, moulting frequency and the maximal live weight reached were higher when fed on Tetramin. (3) Egg production in the culture fed Pleurococcus was twice that fed on Tetramin, due to the more fertile intermoult periods without oviposition in animals fed Tetramin. The egg quality seemed to be lowered in the algae-fed animals rather less than in those fed with fishfood. (4) In both cultures, an increase of 35–40% of the metabolic rate at the start of the experiment was observed. This increase was maintained with a Tetramin diet, whilst it disappeared in cultures fed Pleurococcus. The F₁ generation of both groups showed an increased metabolic rate, that from Tetramin-fed being significantly higher than that from Pleurococcus-fed animals. (5) It is suggested that the initial increase in metabolism is a result of excess food, and the increased level of oxygen uptake in animals on a Tetramin diet the result of inadequacy of the composition of the fishfood for egg production, thus channelling the energy uptake mainly into growth and metabolism. (6) Neither Tetramin nor Pleurococcus are considered to provide an adequate diet for I. viridis, as reproductive success differed considerably from field conditions.     

Bone growth marks reveal protracted growth in New Zealand kiwi (Aves,Apterygidae)

The presence of bone growth marks reflecting annual rhythms in the cortical bone of non-avian tetrapods is now established as a general phenomenon. In contrast, ornithurines (the theropod group including modern birds and their closest relatives) usually grow rapidly in less than a year, such that no annual rhythms are expressed in bone cortices, except scarce growth marks restricted to the outer cortical layer. So far, cyclical growth in modern birds has been restricted to the Eocene Diatryma, the extant parrot Amazona amazonica and the extinct New Zealand (NZ) moa (Dinornithidae). Here we show the presence of lines of arrested growth in the long bones of the living NZ kiwi (Apteryx spp., Apterygidae). Kiwis take 5–6 years to reach full adult body size, which indicates a delayed maturity and a slow reproductive cycle. Protracted growth probably evolved convergently in moa and kiwi sometime since the Middle Miocene, owing to the severe climatic cooling in the southwest Pacific and the absence of mammalian predators.     

CONCERNING THE INFLUENCE OF POLARIZED LIGHT ON THE GROWTH OF SEEDLINGS

While these experiments are not exhaustive, a sufficient number have been made to warrant the statement that the effect of polarized light of the visible spectrum on the growth of various seedlings and See PDF for Structure more particularly on the growth of Lupinus albus is somewhat different from that of non-polarized light. This is especially convincing in view of the results obtained with double sets of plants which were alternately exposed to polarized and non-polarized lights of the same intensities and at the same temperature. In every experiment thus performed the set which was placed in a polarizing chamber grew better. It is, furthermore, interesting to note that the phenomenon above observed did not take place when the seed portion of the plants was protected from light by wrapping with tinfoil. This agrees well with previous findings concerning the action of diastase on starch in polarized light. The above researches will be continued on a more elaborate scale but the results so far obtained are deemed worthy of publication in the form of a preliminary communication at the present time.     

Regulation of glial size by eicosapentaenoic acid through a novel Golgi apparatus mechanism

Coordination of cell growth is essential for the development of the brain, but the molecular mechanisms underlying the regulation of glial and neuronal size are poorly understood. To investigate the mechanisms involved in glial size regulation, we used Caenorhabditis elegans amphid sheath (AMsh) glia as a model and show that a conserved cis-Golgi membrane protein eas-1/GOLT1B negatively regulates glial growth. We found that eas-1 inhibits a conserved E3 ubiquitin ligase rnf-145/RNF145, which, in turn, promotes nuclear activation of sbp-1/ SREBP, a key regulator of sterol and fatty acid synthesis, to restrict cell growth. At early developmental stages, rnf-145 in the cis-Golgi network inhibits sbp-1 activation to promote the growth of glia, and when animals reach the adult stage, this inhibition is released through an eas-1-dependent shuttling of rnf-145 from the cis-Golgi to the trans-Golgi network to stop glial growth. Furthermore, we identified long-chain polyunsaturated fatty acids (LC-PUFAs), especially eicosapentaenoic acid (EPA), as downstream products of the eas-1-rnf-145-sbp-1 pathway that functions to prevent the overgrowth of glia. Together, our findings reveal a novel and potentially conserved mechanism underlying glial size control.

The molecular mechanisms underlying the regulation of glial and neuronal size are poorly understood. This study in nematodes reveals eicosapentaenoic acid as the downstream product of a pathway that functions to prevent the overgrowth of glia, suggesting a novel and potentially conserved mechanism underlying glial size control.     

不同饵料对稀有鲫生长和繁殖的影响

饵料对鱼类生长发育和繁殖具有重要影响。为了筛选稀有鲫(Gobiocypris rarus)幼鱼和成鱼阶段最适投喂方式, 实验将出膜5周末(日龄为35 day after hatching)的幼鱼随机分为5个组: A组投喂丰年虫; B组每周前6d (days)投喂丰年虫, 后1d投喂商业化微颗粒S3饲料; C组每周前3.5d投喂丰年虫, 后3.5d投喂饲料; D组每周前1d投喂丰年虫, 后6d投喂饲料; E组一直投喂饲料; 各组均采用饱食投喂策略。每2周统计生长、存活指标, 直至第21周(147 dah), 在17周(119 dah)取材用于观察性腺发育程度。在产卵后统计各组产卵量、孵化率和子代畸形率。结果显示: (1)E组存活率和特定生长率显著低于其他组(P<0.05); (2)从产卵量、孵化率和子代畸形率上看, B组产卵量显著高于其他组(P<0.05); (3)从性腺组织学上看, 不同投喂方法对精巢的成熟度无显著影响, 但投喂过丰年虫的稀有鲫卵巢发育成熟度显著优于E组。研究结果提示:适量加入丰年虫比单一投喂活饵或饲料更有利于稀有鲫的生长和繁殖。建议在标准化养殖过程中, 幼鱼和成鱼期的稀有鲫采取丰年虫与饲料投喂频次比值为6﹕1的方式最佳。