The endocrine cells of the rectum of adult ox.

In order to identify the endocrine cell types in various parts of the Ruminant gut, we have applied ultrastructural, both morphological and cytochemical, techniques, in parallel to the histochemical ones, to study the rectal mucosa of the adult Ox. In these studies we show that: "EC" cells, of the intestinal type, contain predominantly pleiomorphic granules, which are very electron dense and heavily reactive to "Masson" and "Grimelius" methods; "L" cells are recognizable by their numerous granules, which are fairly homogeneous in shape and osmiophilia. They do not react with "Masson" and are weak or negative to Grimelius s reaction. These granules occur near to others that are less dense, unreactive to "Masson", and that contain an argyrophilic matrix, with an eccentric electron dense core, which does not react with silver; "F-like" cells contain granules which are variable in shape, size and osmiophilia. They are unreactive to "Masson" and weak or unreactive to Grimelius silver; "H" cells contain few, small and uniformly osmiophilic granules. These are unreactive to "Masson" and uniformly reactive to "Grimelius". Our data suggest that the morphology, frequency and distribution of the cell types we have identified in the mucosa of the bovine rectum correspond with those reported in large intestine and rectum of Monogastrics, as by other authors described.     

"Red" fibres of pigeon pectoralis major muscle are "type II red".

On the basis of the histochemical activity of succinic dehydrogenase, only two fibre-types are distinguished in pigeon pectoralis major muscle. These are narrow "Red" and broad "White". The histochemical activity of myofibrillar ATPase was studied in these two distinct fibre-types. Both fibre-types showed high activity for the ATPase. "Red" fibres of pigeon pectoralis were not alkali-labile, at incubation pH 9.4, as were the "Type I" fibres of both avian and mammalian muscles. Again unlike "Type I" fibres, the "Red" fibres of pigeon pectoralis lacked the characteristic activation of acid-preincubated ATPase reaction. Pigeon pectoralis "Red" fibres are known to possess some characteristics of fast-twitch fibres (e.g. high fat, considerable phosphorylase, fibrillenstruktur myofibrillar arrangement, focal "en plaque" pattern of nerve endings). It is emphasized, therefore, that the pigeon pectoralis "Red" fibres are not equivalent to "Type I or slow-twitch", muscle fibres, but they are possibly "fast-twitch fatigue resistent or Type II Red" muscle fibres.     

Difference in the ability of neonatal and adult denervated muscle to accumulate acetylcholinesterase at the old sites of innervation

In adult rat sternocleidomastoid muscle, AChE is concentrated in the region rich in motor end-plates (MEP). All major AChE forms, "16 S," "10 S," and "4 S," are accumulated at high levels, and not only "16 S" AChE. After denervation, muscle AChE decreases; 2 weeks after denervation, low levels (20-40% of control) are reached for all forms. During the following weeks, a slow but steady increase in "10 S" and "16 S" AChE occurs in the denervated muscle. At this stage, all forms are again observed to be highly concentrated in the region containing the old sites of innervation. Thus, in adult rat muscle the structures able to accumulate "16 S," "10 S," and "4 S" AChE in the MEP-rich regions remain several months after denervation. In normal young rat sternocleidomastoid muscle at birth, all AChE forms are already accumulated in the MEP-rich region. After denervation at birth, the denervated muscle loses its ability to keep a high concentration of "4 S," "10 S," and "16 S" AChE in the old MEP-rich region. All AChE forms are still present 1 month after denervation, but they are decreased and diffusedly distributed over the whole length of the muscle. In particular, "16 S" AChE is detected in the same proportion (10-15%) all along the denervated muscle. Thus, the diffuse distribution of AChE, and especially "16 S" AChE, after neonatal denervation, contrasts with the maintained accumulation observed in adult denervated muscle. It seems that denervation of young muscle results in a specific loss of the muscle ability to concentrate high levels of all AChE forms at the old sites of innervation.     

Involvement of dopamine in amplification of cortical signals activating NMDA-receptors in the striatum (hypothetic mechanism)

Possible mechanisms of amplification/attenuation of cortical signals opening or not opening NMDA-channels in striatal spine cells while passing through basal ganglio-thalamocortical network and relegated to either "strong" or "weak" signals, are considered. In absence of dopamine, a relative increase in intensity of the "strong" or "weak" cortical signals should result in the LTP/LTD on both striatonigral and striatopallidal cells, the thalamic cells being affected in the opposite way. Activation of the dopamine receptors on the striatonigral (striatopallidal) cells prompts the LTP/LTD expression. Thereof, the "strong" cortical signals are synergistically amplified whereas the "weak" signals are synergistically attenuated at the thalamic output.     

The endocrine cells of the pyloric glands of adult ox

As part of a project to identify the endocrine cells ("EC" and "APUD" series) of the gastroenteric apparatus of ruminants, the ultrastructure of the mucosa of the pyloric glands of adult ox was studied morphologically and cytochemically, in parallel with a light microscope histochemical analysis. The results show that: the "EC" cells (producing 5-HT) are recognizable by their secretory granules which are heavily osmiophilic, argentaffin ("Masson") and argyrophilic ("Grimelius"). A further distinction is possible on the basis of their morphological features: the "EC" cells of the gastric type (which belong to the "ECn" group) contain granules fairly homogeneous in shape and size, while the "EC" cells of the intestinal type (or "EC1") show granules which are more pleiomorphic and variable in size. Of particular interest is the presence in some cells of granules typical of the "EC" cells of the intestinal type, in the vicinity of a few others, which appear quite similar to those of the adjoining exocrine cells; the "G" cells (gastrin producing) contain medium sized granules, which are unreactive to "Masson" and poorly argyrophilic. Their morphology is rather diverse; some of them (these are the "typical" cells) have a granular and weakly electron dense content, others (which we consider "atypical") show a homogeneous and heavily osmiophilic core, with an eccentrical empty area. Also present are granules whose appearance is intermediate and empty vesicles; the "D cells" (somatostatin producting) show round, medium sized granules which have a granular, moderately osmiophilic core, tightly encircled by the membrane. These granules are unreactive to "Masson" and to "Grimelius"; the "D1" cells (whose function is yet unclear) contain small, round granules whose core is variously but discretely electron dense and not always homogeneous; they are unreactive to "Masson" and fairly argyrophilic. These granules may be numerous and packed, or scarce; in this latter instance the few granules are intermingled with variously running tufts of parallel filaments, thus resembling the "P" cells, whose function is still undefined. These data show therefore that the types of endocrine cells we have identified in the pyloric glands of adult ox correspond to those described in other mammals; "X" and "F" or "PP" cell appear to be lacking.     

Histology of the reproductive tract of hybrids between gonochoristic males and parthenogenetic females of Lepidodactylus lugubris in French Polynesia (Reptilia, Gekkonidae).

Parthenogenetic populations of the gecko Lepidodactylus lugubris are widespread throughout Polynesia. They often occur parapatrically, and occasionally syntopically, with the increasingly rare bisexual populations. In these instances, a small number of hybrid individuals occur and include both "female" and "male" external phenotypes, both with greatly reduced gonads. Histological examination demonstrates that these hybrids possess small ovotestes. The differentiation of the cortical tissue is identical in both "male" and "female" hybrids, but the medullary tissue is more developed in "males." The remainder of the genital tract in "females" resembles that of fertile females in the parthenogenetic and bisexual populations. By contrast, the "male" hybrids are markedly intersexual. In one of the two specimens autopsied, the hemipenes are more or less the same size as those of bisexual males, and the sexual segment of the kidney is hypertrophied and serous. In the other hybrid "male," the hemipenes have a structure similar to that seen in females, and the sexual segment of the kidney is poorly differentiated. In both hybrid "males," the ductus deferens is extremely narrow and further reduced in its middle portion; oviducts are present and resemble those of normal or hybrid females. Thus, embryonic-like gonads are associated with complete and normal female reproductive ducts in hybrid "females." Hybrid "males" also have embryonic-like gonads and feminized genital ducts but associated with secondary sexual characters that match those of sexually active or quiescent normal males.     

蕲州地区的蕲艾、青蒿、黄花蒿与茵陈的考订

<正> 蕲州是我国中药材主要产地之一,是湖北省蕲春县的一个集镇,,是我国中医药大师李时珍的家乡。该地区生长的菊科蒿属植物Artemisia Linn。颇多,其中入药的有十余种,并在李时珍《本草纲目》中曾有记载。这里仅对该地区常见入药的蕲艾、青蒿、黄花蒿与茵陈结合《本草纲目》记载的材料作初步的考订。     

Novel chloroplasts and unusual cellular ultrastructure in the "resurrection" plant Myrothamnus flabellifolia Welw. (Myrothamnaceae)

The vacuoles of three "resurrection" plants, Myrothamnus flabellifolia, Anastatica hierochuntica and Selaginella dregei were found to contain large quantities of osmiophilic material which may be part of the "resurrection" mechanism. Myrothamnus differed from the others by having mitochondria, and possibly plastids, which are separated from the remainder of the cytoplasm by sheaths or membranes during desiccation. Upon "resurrection" these barriers appear to be perforated and explain in part the faster rate of "resurrection" in Myrothamnus than in other "resurrection" plants. The chloroplasts of Myrothamnus are remarkable in that they possess "staircase" granum stacks of a type not previously described in any other plant tissue.     

The Dream as Text, The Dream as Narrative

The concepts of text and narrative are reviewed in terms of their appropriate application to the study of dreams. It is proposed that, once experienced, all dreams are texts, but that not all of these texts are narratives. Blending Jung's proposal for the form of the average dream with basic terms from narratology, dream data are employed in order to examine the narrativity of dreams, and by way of inquiring into cognitive aspects of narrative structure. Questions about the relation between language and narrative structure on the one hand, and between dreaming and language on the other are also briefly taken up.     

Immunolocalization of β-(1→4) and β-(1→6)-D-galactan epitopes in the cell wall and Golgi stacks of developing flax root tissues

Summary Most cell wall components are carbohydrate including the major matrix polysaccharides, pectins and hemicelluloses, and the arabinogalactan-protein proteoglycans. Both types of molecules are assembled in the Golgi apparatus and transported in secretory vesicles to the cell surface. We have employed antibodies specific to -(16) and -(14)-D-galactans, present in plant cell wall polysaccharides, in conjunction with immunofluorescence and electron microscopy to determine the location of the galactan-containing components in the cell wall and Golgi stacks of flax root tip tissues. Immunofluorescence data show that -(14)-D-galactan epitopes are restricted to peripheral cells of the root cap. These epitopes are not expressed in meristematic and columella cells. In contrast, -(16)-D-galactan epitopes are found in all cell types of flax roots. Immunogold labeling experiments show that both epitopes are specifically located within the wall immediately adjacent to the plasma membrane. They are also detected in Golgi cisternae and secretory vesicles, which indicates the involvement of the Golgi apparatus in their synthesis and transport. These findings demonstrate that the synthesis and localization of -(14)-D-galactan epitopes are highly regulated in developing flax roots and that different -linked D-galactans associated with cell wall polysaccharides are expressed in a cell type-specific manner.     

不同立地类型和土壤类型对"裕丹参"生长和有效成分含量的影响

采用大田种植和盆栽方法,分别研究了不同的立地类型(平地、阳坡、阴坡和坡地)和土壤类型(砂土、壤土和黏土)对产自河南省方城县的"裕丹参"(Salvia miltiorrhiza Bunge)生长和有效成分含量的影响效应.结果表明:在不同立地条件下,"裕丹参"的各项生长和根系产量指标以及根系中丹参酮ⅡA和丹酚酸B含量均有明显差异.随种植时间的延长,平地、阳坡和坡地种植的"裕丹参"单株地上部干质量均逐渐降低,而阴坡种植的单株地上部干质量先升高后逐渐降低;但在不同立地类型下,单株根系干质量和丹酚酸B含量均随种植时间的延长逐渐升高,而丹参酮ⅡA含量则先降低后升高.采收期,平地种植的"裕丹参"的单株地上部干质量、单株根系干质量和鲜质量以及根系鲜产量均最高,平地和坡地种植的"裕丹参"根直径较大,阳坡种植的"裕丹参"根长最长,阳坡和坡地种植的"裕丹参"单株根数、根系中丹参酮ⅡA和丹酚酸B含量也较高,而阴坡种植的"裕丹参"的各项生长和根系产量指标以及丹参酮ⅡA和丹酚酸B含量均最低.在不同类型土壤中,"裕丹参"的根系性状和根系中丹参酮ⅡA和丹酚酸B含量总体上差异显著,其中,用砂土种植的"裕丹参"的根直径、根长、单株根系鲜质量和干质量以及根系中丹参酮ⅡA和丹酚酸B含量均最高,但单株根数最少;用黏土种植的"裕丹参"根系生长总体最差,但单株根数最多;用壤土种植的"裕丹参"根系中丹参酮ⅡA和丹酚酸B含量则最低.综合研究结果显示:"裕丹参"适宜种植于砂土的坡地或阳坡.     

Human Races: A Genetic and Evolutionary Perspective

Race is generally used as a synonym for subspecies , which traditionally is a geographically circumscribed, genetically differentiated population. Sometimes traits show independent patterns of geographical variation such that some combination will distinguish most populations from all others. To avoid making "race" the equivalent of a local population, minimal thresholds of differentiation are imposed. Human "races" are below the thresholds used in other species, so valid traditional subspecies do not exist in humans. A "subspecies" can also be defined as a distinct evolutionary lineage within a species. Genetic surveys and the analyses of DNA haplotype trees show that human "races" are not distinct lineages, and that this is not due to recent admixture; human "races" are not and never were "pure." Instead, human evolution has been and is characterized by many locally differentiated populations coexisting at any given time, but with sufficient genetic contact to make all of humanity a single lineage sharing a common evolutionary fate.     

Synchronous (synphaseous) additive models for mitochondrial ATP synthetase complex and for other energy transducing systems of cells (a hypothesis)

There exist some energy transducing enzymes containing immobile molecules of substrates which are not exchangeable during protein functioning. According to the proposed models the immobile substrates are localized at the "idle" (or "partial" or "imitational") catalytic sites, which differ from normal ("working") active sites of enzymes. Only some steps of a complete reaction sequence which take place at the "working" sites are carried out at the "idle" sites. On the other hand, cyclic conversion of the immobile substrate at an "idle" catalytic site may include some steps which are absent in the "working" site cycle. The occurrence of identical steps on the "idle" and "working" catalytic sites allows to synchronize their action through conformational interconversions of tightly packed and structurally related "idle" and "working" subunits of the enzyme. The presence of covaletly bound substrates or substrates localized in closed cavities of the "idle" sites allows to synchronize the action of many monomers containing such sites due to the absence of the rate-limiting step of simultaneous saturation of many catalytic sites by substrate molecules from solution, and due to the lack of substrate inhibition on the "idle" sites. The functions of the "idle" sites are miscellaneous e.g. in ion-transporting systems these sites are directly involved in ion translocation. In the actomyosin complex the "idle" sites imitate conformational alterations of "working" sites, thus allowing synchronous functioning of the polymeric structure. Variations in the number of the "idle" sites operating simultaneously with one "working" site allow to regulate some parameters of enzymatic processes, e.g. the stoichiometry (number of transported ions per ATP hydrolysed (or synthesised) or electron-transported, or hv-absorbed ones) for ion transported systems or the ratio (velocity of contraction to developed efforts) for the actomyosin complex.     

Opossum (Didelphis virginiana) "little" and "big" gastrins

1. "Little" gastrins from most mammalian species are 17 amino acid peptides and the precursor "big" gastrins are 34 amino acid peptides. 2. "Little" gastrins of the New World hystricomorphs, guinea-pig and chinchilla, are 16 amino acid peptides due to deletion of a glutamic acid in the region 6-9 from their NH2-terminus and the corresponding "big" gastrins are 33 amino acid peptides. 3. Antral gastrins from the opossum, a New World marsupial, have a glutamic acid deletion in the same region as the hystricomorph gastrins. 4. Opossum "big" gastrin is a 33 amino acid peptide with the following sequence: less than ELGPQDLPYLTADLSKKQGPWLEEEEAYGWMDF#.     

Chapter V: The Active and Passive, "Receptive" and "Productive" in Learning a Second Language

Although in contemporary methods and (insofar as we are justified in using the term at all) in the contemporary psychology of foreign-language learning, the concepts of "active" and "passive" are widely used with reference to aspects of learning, to methods, habits, and models, these concepts are actually quite vague. This raises the necessity of systematically examining the main problems associated with maintaining a distinction between "active" and "passive" in language acquisition.     

What's in a Cause?: The Pragmatic Dimensions of Genetic Explanations

The paper argues for a pragmatic account of genetic explanation. This is to say that when a disease or other trait is termed genetic, the reasons for singling out genes as causes over other, also necessary, genetic and nongenetic conditions are not wholly theoretical but include pragmatic dimensions. Whether the explanation is the presence of a trait in an individual or differences in a trait among individuals, genetic explanations are context-dependent in three ways: they are relative to a causal background of genetic and nongenetic factors; they are relative to a population; and they are relative to the present state of knowledge. Criteria like causal priority, nonstandardness, and causal efficacy that purport to distinguish objectively between genetic causes and nongenetic conditions either incorporate pragmatic elements or fail for other reasons. When the pragmatic dimensions of genetic explanations are recognized, we come to understand the current phenomenon of geneticization to be a reflection of increased technological capacities to manipulate genes in the laboratory, and potentially the clinic, rather than theoretical progress in understanding how diseases and other traits arise. This calls into question the value of the search for theoretical definitions of designations like genetic disease or genetic susceptibility as directives for action.     

Distinct roles of specific fatty acids in cellular processes: implications for interpreting and reporting experiments

Plasma contains a variety of long-chain fatty acids (FAs), such that about 35% are saturated and 65% are unsaturated. There are countless examples that show how different FAs impart specific and unique effects, or even opposing actions, on cellular function. Despite these differing effects, palmitate (C16:0) is regularly used to represent "FAs" in cell based experiments. Although palmitate can be useful to induce and study stress effects in cultured cells, these effects in isolation are not physiologically relevant to dietary manipulations, obesity, or the consequences of physiological concentrations of FAs. Hence, authors should avoid conclusions that generalize about "FAs" or "saturated FAs" or "high-fat diet" effects if only a single FA was used in the reported experiments.     

Microfilaments and microtubules in isolated fiber cells of Trichoplax adhaerens (Placozoa)

Summary Fiber cells isolated by mechanical disruption of the tissue in Ca²⁺-free sea water attach firmly to the substrate by discrete adhesion plaques. They are capable of forming a lamellipodium and long, slender extensions while the cell bodies remain stationary. The extensions are slowly elongated but can suddenly be withdrawn by contraction. Bundles of F-actin are attached with their plus ends close to the tips of the extensions. Within the cell body, microfilaments form a loose cortical layer and criss-crossing patches. Microtubules are not present in newly formed extensions but seem to stabilize older extensions. In these, they are bundled by crossbridges and oriented lengthwise. In the cell body, 37 nm macrotubules are found as well as the prevailing microtubules 24 nm in thickness. They radiate from an organizing center close to the mitochondrial complex, which can, however, also give rise to normal microtubules. Since this organizing center seems to nucleate either macrotubules or microtubules, but never both at the same time, it is speculated that it may exist in two alternative states.