Sexual ambiguities: definition, management, classification

The authors define the field of the sexual ambiguities including not only the cases of ambiguousness in the external genitals, but also those cases which present anomalies in the external or internal genitals or in the gonads, with more or less evident characteristics of the other sex, even if there is no doubt as to the sex attribution. On the contrary the cases with only the lack of gonads are excluded. After a brief recall to some aspects of the sexual differentiation, the authors point up the importance of genetic counselling not only to let a precocious sex registration at the General Register Office, but also with the purpose of a genetic prevention and of a quick corrective intervention. At last the authors propose a personal classification of these defects.     

Responses to a simple barter task in chimpanzees, Pan troglodytes

Chimpanzees (Pan troglodytes) frequently participate in social exchange involving multiple goods and services of variable value, yet they have not been tested in a formalized situation to see whether they can barter using multiple tokens and rewards. We set up a simple barter economy with two tokens and two associated rewards and tested chimpanzees on their ability to obtain rewards by returning the matching token in situations in which their access to tokens was unlimited or limited. Chimpanzees easily learned to associate value with the tokens, as expected, and did barter, but followed a simple strategy of favoring the higher-value token, regardless of the reward proffered, instead of a more complex but more effective strategy of returning the token that matched the reward. This response is similar to that shown by capuchin monkeys in our previous study. We speculate that this response, while not ideal, may be sufficient to allow for stability of the social exchange system in these primates, and that the importance of social barter to both species may have led to this convergence of strategies.     

Responses of intertidal nematodes to short-term anoxic events

We investigated tolerance to, and activity of, nematodes in hypoxic and anoxic/partially sulphidic conditions and their ability for recovery after reoxygenation of anoxic sediment. To this end, sediments from an intertidal flat were incubated under oxic, suboxic and anoxic/partially sulphidic conditions for a 14-day period and the final density of nematodes, as a group, and of the most abundant species were assessed. In one treatment, oxygen was restored after anoxic incubation. The incorporation of ¹³C, originating from labeled algae added on top of the sediment, was taken as an indication of nematode activity.Short-term suboxic and anoxic/partially sulphidic conditions had similar structuring impact on the nematode community, reducing total densities by about one third. Survival in suboxic and anoxic/partially sulphidic conditions was species-specific. Daptonema setosum, D. tenuispiculum and Chromadora macrolaima, dominant in the oxic incubation, disappeared when the oxygen level was reduced. The density of the other dominant species was slightly reduced (Sabatieria pulchra), similar (Terschellingia communis) or even increased in the suboxic and anoxic conditions (Metachromadora vivipara). The activity level of these three species was, however, reduced under oxygen limitation. Our results are discussed in terms of the life-history strategies of these species.     

Sequence data: Magnitude and implications of some ambiguities

Summary Glx and Asx ambiguities introduce errors into evolutionary conclusions drawn from the sequences of incompletely analyzed proteins. These errors are of sufficient magnitude to invalidate some of these conclusions.     

Vectors permitting visual monitoring of simple transposition events

The construction and use of two novel transposon(Tn)-delivery vectors is described. These vectors carry Inc.W or Inc.N broad-host-range transfer functions cloned next to the narrow-host-range replicon of pBR329. The host specificities of pSLX10 and pSLX23 both complement and extend the host specificities of existing Tn delivery vectors. Plasmids pSLX10 and pSLX23 were shown to transfer at high frequency in intergeneric matings. The lux genes which are present on each vector permit the visual monitoring of transconjugants which have retained a Tn element, but are devoid of plasmid molecules. pSLX10 and pLSX23 were efficiently used to generate a range of auxotrophic mutants in various strains of Pseudomonas as well as to clone genes from Serratia liquefaciens. These vectors may have general applicability to identify and clone genes in a wide range of Gram-negative bacteria.     

中国西南部地区植被对极端气候事件的响应

在全球气候变化背景下, 极端气候事件频发。中国西南部地区植被对于气候变化及极端气候事件的响应较为敏感。为探究西南部地区植被对极端气候事件的响应程度, 该文采用Pettitt检验、趋势分析法对数据进行分析, 并对数据进行去趋势处理, 分析去趋势前后极端气候指数与归一化植被指数(NDVI)的相关关系。结果表明: (1) 1982-2015年西南部地区植被NDVI呈现显著上升的趋势, NDVI在1994年发生突变, 突变前上升不显著, 突变后呈现显著上升的趋势; (2)去趋势前, 1982-2015年间, 极端降水指数与NDVI显著相关的仅有1日最大降水量, 其与NDVI显著正相关; 除气温日较差外, 其他极端温度指数均与NDVI显著相关。1994-2015年间, 1日最大降水量与NDVI显著正相关, 降水日数与NDVI显著负相关; 在极端温度指数中, 日最低气温最大值、暖昼日数、夏季日数、生长季长度和气温日较差与NDVI显著正相关, 冷昼日数、冰冻日数、冷夜日数和霜冻日数与NDVI显著负相关。1982-2015年间NDVI对年平均气温的响应最强, 而在1994-2015年间NDVI对夏季日数和气温日较差的响应强于对年平均气温的响应。(3)去趋势后, 极端降水指数与NDVI的相关性在两个时段都不显著; 而日最高气温最大值、暖昼日数、夏季日数和气温日较差在这两个时段与NDVI显著正相关, 但其与NDVI的相关系数都在1994-2015年间更高。气温日较差在两个时段与NDVI的相关系数都最高。只在1982-2015年冷昼日数与NDVI显著负相关。     

Responses of simple and non-oriented cells to stimuli of variable duration in areas 17 and 18 of cat visual cortex.

Single unitresponses to photic stimuli of variable duration were studied in the cat visual areas 17 and 18. The closed-chamber technique was used to record extracellularly impulsive electrical activity in locally anaesthetized, Flaxedil-paralyzed and artificially ventilated cats. Stimulus duration ranges between 0.020 and 10 sec, the background luminance and the intensity of stimuli being constant. We found a first group of cells which fire independently of the stimulus duration; a second group which fire in close relation to the stimulus duration in a rather wide range of values, and a third group which fire monotonously as long as the stimulus goes on. The three groups of cells are supposed to be three functionally different types of cortical cells.     

A simple method for determination of gait events.

Simple and effective methods for determining the timing of gait events are necessary for the proper normalization and statistical analysis of gait data when a variety of gait measurements are available. The approach presented was developed for cases in which overall center of pressure under the body and marker trajectories are being measured over multiple steps. The new method presented uses the relative positioning of the overall center of pressure and an ankle marker in the direction of forward progression for the determination of "heel-contact" and "toe-off" events. The difference between the locations of the overall center of pressure and the ankle in the direction of progression readily delineates the timing of these events. The new method was tested against force records from individual force platforms and was found to detect "heel-contact" events an average of 1 sample (at a sampling frequency of 120Hz, 0.00833s) before the event found using the individual force platforms. "Toe-off" events were found an average of 2 samples (0.0167s) prior to the events found using individual force plates. The method appears new and is attractive because of its simplicity in determining gait events when the appropriate gait measurements are available.     

Elimination of matrix-based interferences to a fluorescent nitrite/nitrate assay by a simple filtration procedure

Pathophysiological levels of oxygen radical metabolites have been studied as indicators of trauma caused by burn insult. The 2, 3-diaminonaphthalene assay is routinely used in the determination of nitrite/nitrate levels in biological fluids and cellular extracts as one indicator of nitric oxide activity. Several laboratories, including ours, have noted matrix-based interferences resulting in decreased assay sensitivity during nitrite/nitrate analysis. We evaluated filtration using Millipore Ultrafree-MC 10,000 NMWL filters for the ability to eliminate matrix-based interferences from human serum and tissue culture medium, thereby restoring assay sensitivity.     

Gene amplification in multidrug-resistant cells: molecular and karyotypic events

The two theories of pancreatic enzyme secretion, those of exocytosis and transmembrane flow, are described. Data thought to support the theory of transmembrane flow of single molecules from pancreatic acinar cells are first reviewed, and the conditions which could allow these data to be explained by the theory of exocytosis of enzyme quanta, i.e. secretory granules, are then discussed. The evidence suggesting short-term modulation of the composition of pancreatic juice is also considered, and its possible explanations at the organ and cellular level are discussed, in the light of suggested theories on enzyme secretion pathways.     

Responses of crayfish neurons and glial cells to photodynamic impact: Intracellular signaling,ultrastructural changes,and neuroglial interactions

Photodynamic therapy (PDT), an inducer of oxidative stress, is used for treatment of cancer, including brain tumors. To study the mechanisms of photodynamic injury of neurons and glial cells (GC), we used a simple model object — isolated crayfish mechanoreceptor consisting of a single sensory neuron surrounded by a multilayered glial envelope. PDT caused inhibition and elimination of neuronal activity, impairment of intracellular organelles involved in the biosynthetic, bioenergetic, and transport processes and neuroglial interactions, necrosis of neurons and glial cells, and in glial apoptosis. PDT-induced death of a neuron and GC was mediated by intercellular molecular messengers and intracellular signaling cascades. PDT-induced inhibition and elimination of neuronal activity was associated with opening of mitochondrial permeability transition pores, Ca²⁺ release into cytosol, protein kinase C and NO synthase activities. Necrosis of neurons was mediated by protein kinases B/Akt, GSK-3β and mTOR, opening of mitochondrial permeability transition pores and Ca²⁺/calmodulin/CaMKII pathway. NO and GDNF reduced neuronal necrosis. Multiple signal pathways, such as phospholipase C/Ca²⁺, Ca²⁺/calmodulin/CaMKII, Ca²⁺/PKC, Akt/mTOR, MEK/p38, and protein kinase G mediated PDT-induced necrosis both in glial cells and in neurons. NOS/NO and neurotrophic factors NGF and GDNF protected glial cells and demonstrated antinecrotic activity. Glial apoptosis was reduced by neurotrophic factors NGF and GDNF, protein kinase C, and MAP kinase JNK. In contrast, mitochondrial permeability transition pores and phospholipase C, which mobilize intracellular Ca²⁺, NOS/NO/protein kinase G, proteins GSK-3β and mTOR, stimulated apoptosis of glial cells. The schemes of involvement of various inter- and intracellular signaling processes in the responses of neurons and GC to PDT are developed.     

Regulatory T cells in CNS injury: the simple, the complex and the confused

Regulatory CD4(+)CD25(+)Foxp3(+) T cells (Tregs) have been the focus of significant attention for their role in controlling immune responses. Although knowledge of Treg biology has burgeoned, wide gaps remain in our understanding of Treg function under both normal and pathological conditions. Pioneering studies demonstrated roles for Tregs in cancer and autoimmune diseases, including experimental autoimmune encephalitis, and this knowledge is often applied to other pathologies including neurodegenerative conditions. However, differences between immunity in neurodegeneration and in malignancy or autoimmunity are often neglected. Thus, Treg manipulations in central nervous system (CNS) neurodegenerative conditions often yield unexpected outcomes. In this piece, we explore how the immunology of neurodegeneration differs from that of cancer and autoimmunity and how these differences create confusion about the role of Tregs in neurodegenerative conditions.     

A simple, selective method for freeze-fracturing spherical cells

A simple and selective method for freeze-fracturing spherical cells is described. The cells are loaded into the holes of a thin nickel screen. A metal hat is applied to the cell monolayer and the whole assembly, hat-cells-screen, is frozen and then fractured by ripping the hat off. The fractured face on the screen is replicated. By varying the size of the screen holes and by applying the hat to either side of the screen, this method can selectively expose the E face (or the outer half of plasma membrane), the P face (or the inner half of the plasma membrane), or the cytoplasm of the cells. It also provides a means to produce fractures at a preselected area on the cell, if the cells can be loaded onto the screen in an oriented fashion.     

Genetic variation in Malaysian oysters: taxonomic ambiguities and evidence of biological invasion

Genetic diversities in two cultured oyster species, Crassostrea iredalei (Faustino 1932) and Crassostrea belcheri (Sowerby 1871) were assessed using a 581-nucleotide fragment of the mtDNA cytochrome oxidase subunit 1 (CO1) gene. A total of 103 C. iredalei individuals and 120 C. belcheri from 12 populations were sampled along the coast of Malaysia. Trees of unique haplotype samples generated based on Neighbor-Joining (NJ) algorithm revealed that many individuals had been misidentified and did not cluster with their presumed species based on morphological identification. BLAST results of DNA sequences showed presence of previously unreported C. madrasensis in Peninsular Malaysian waters (98% maximum identity). The true identity of the Muar (Crassostrea sp.) and Semporna (Saccostrea sp.) populations were unresolved by two BLAST search and showed less than 88% identity with other species in GenBank. Repeated analysis of these two populations using 487 bp of the mitochondrial 16S gene data showed only a maximum identity less than 97%. Hence, the identity of these specimens remains unclear. Evolutionary divergences within presumed species were 0.001–0.011 and 0.034–0.313 between species. Findings from this study have important implications for aquaculture, management and monitoring of cultured populations as well as conservation of wild oyster species in Malaysia.