The reproductive biology of female Père David's deer (Elaphurus davidianus)

Data for this study came from breeding records of 27 Père David's (Elaphurus davidianus) hinds maintained in large pastures and from estrous records of four hand-reared nulliparous hinds. The mean estrous cycle length ranged from 17.5 to 19.6 days. Standing estrus resembled that of other cervids, except that a low, moaning vocalization was given in response to contact, and activity (as measured by pedometers) did not increase. Mean gestation length was 183.38 ± SD 6.11 days (n = 21), and nearly all females conceived in the second and third years. The median interbirth interval was 362 days. The median birth date was April 8, and 80% of the births occurred over a 9.5-week period. Multiparous hinds gave birth an average of 20.5 days earlier in the season than primiparous hinds. There was no dimorphism in birth weight. The results are discussed in light of comparative data for other species.     

The effect of size on the optimal shapes of gliding insects and seeds

Conventional aerodynamic arguments suggest that possession of high aspect ratio wings will always improve the flight performance of glides. Drag and power will be minimized at intermediate flight speeds. It is shown, however, that as the aspect ratio increases, these minimum drag speeds are reduced, and will fall below the stall speed of the glider. This will happen at lower aspect ratios in small gliders, which operate at higher profile drag coefficients. Increasing the aspect ratio further will improve performance less than this analysis suggests.
A detailed analysis is developed to calculate the optimum shape of small gliders. Profile drag increases with aspect ratio, owing to the fall in the Reynolds number, while induced drag falls with increasing aspect ratio. Minimum drag will be encountered and hence the glide angle will be minimized at intermediate values of aspect ratio. Best glide angles are achieved at low speeds (high lift coefficients) and the optimum aspect ratio increases with the mass of the glider.
Small natural gliders possess large, low aspect ratio wings. The aspect ratios are generally somewhat below those which would produce the best glide angle at stall speed, but should give a reasonable performance over a range of speeds.     

Growth-associated modifications of low-molecular-weight thiols and protein sulfhydryls in human bronchial fibroblasts

The thiol redox status of cultured human bronchial fibroblasts has been characterized at various growth conditions using thiol-reactive monobromobimane, with or without the combination of dithiotreitol, a strong reducing agent. This procedure has enabled measurement of the cellular content of reduced glutathione (GSH), total glutathione equivalents, cysteine, total cysteine equivalents, protein sulfhydryls, protein disulfides, and mixed disulfides. Passage of cells with trypsin perturbs the cellular thiol homeostasis and causes a 50% decrease in the GSH content, whereas the total cysteine content is subsequently increased severalfold during cell attachment. During subsequent culture, transient severalfold increased levels of GSH, protein-bound thiols, and protein disulfides are reached, whereas the total cysteine content gradually declines. These changes in the redox balance of both low-molecular-weight thiols and protein-bound thiols correlate with cell proliferation and mostly precede the major growth phase. When the onset of proliferation is inhibited by maintenance of cells in medium containing decreased amounts of serum, the GSH content remains significantly increased. Subsequent stimulation of growth by addition of serum results in decreased GSH levels at the onset of proliferation. In thiol-depleted medium, proliferation is also inhibited, whereas GSH levels are increased to a lesser extent than in complete medium. Exposure to buthionine sulfoximine inhibits growth, prevents GSH synthesis, and results in accumulation of total cysteine, protein-bound cysteine, and protein disulfides. For extracellular cystine, variable rates of cellular uptake correlate with the initial increase in the total cysteine content observed following subculture and with the GSH peak that precedes active proliferation. The results strongly suggest that specific fluctuations in the cellular redox balance of both free low-molecular-weight thiols and protein sulfhydryls are involved in growth regulation of normal human fibroblasts.     

Brain and Plasma Quinolinic Acid in Profound Insulin-Induced Hypoglycemia

Profound insulin-induced hypoglycemia is associated with early-onset neuronal damage that resembles excitotoxic lesions and is attenuated in severity by antagonists of N-methyl-D-aspartate receptors. Hypoglycemia increases L-tryptophan concentrations in brain and could increase the concentration of the L-tryptophan metabolite quinolinic acid (QUIN), an agonist of N-methyl-D-aspartate receptors and an excitotoxin in brain. Therefore, we investigated the effects of 40 min of profound hypoglycemia (isoelectric EEG) and 1-2 h of normoglycemic recovery on the concentrations of QUIN in brain tissue, brain extracellular fluid, and plasma in male Wistar rats. Plasma QUIN increased 6.5-fold by the time of isoelectricity (2 h after insulin administration). Regional brain QUIN concentrations increased two- to threefold during hypoglycemia and increased a further two- to threefold during recovery. However, no change in extracellular fluid QUIN concentrations in hippocampus occurred during hypoglycemia or recovery as measured using in vivo microdialysis. Therefore, the increases in brain tissue QUIN concentrations may reflect elevations of QUIN in the intracellular space or be secondary to the increases in QUIN in the vascular compartment in brain per se. L-Tryptophan concentrations increased more than twofold during recovery only. Serotonin decreased greater than 50% throughout the brain during hypoglycemia, while 5-hydroxyindoleacetic acid concentrations increased more than twofold during hypoglycemia and recovery. In striatum, dopamine was decreased 75% during hypoglycemia but returned to control values during recovery, while striatal 3,4-dihydroxyphenylacetic acid and homovanillic acid were increased more than twofold during both hypoglycemia and recovery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Linkage of PGK1 to X-linked severe combined immunodeficiency (IMD4) allows predictive testing in families with no surviving male

Summary We present a linkage map of DNA probes around the X-linked severe combined immunodeficiency (IMD4) locus at Xq11-13. DXS159 and PGK1 show no cross-overs with the disease locus (Lod 3.01 at = 0.00). The order of loci is DXS1-DXS106-(DXS159-PGK1-IMD4)-DXS72-DXYS1. Members of families whose carrier status has been established by X-inactivation patterns were included in the analysis. As the probe (pSPT/PGK), which is used for investigation of X-inactivation patterns, has been shown to be linked to the disease itself, it is possible to assign phase in mothers of sporadic cases who have been shown to be carriers, even when they have no surviving male offspring.     

Structural gene isolation and prepeptide sequence of gallidermin, a new lanthionine containing antibiotic

Peptide antibiotics containing lanthionine and 3-methyllanthionine bridges, named lantibiotics are of increasing interest. A new lantibiotic, gallidermin, has been isolated from Staphyloccus gallinarum. Here we report the isolation of its structural gene which we name gdmA. In all lantibiotics so far studied genetically, three peptides can be formally distinguished: (i) the primary translation product, which we call the prepeptide; (ii) the propeptide lacking the leader sequence and (iii) the mature lantibiotic. Unlike the plasmid-coded epidermin, gdmA is located on the chromosome. The gdmA locus codes for a 52 amino acid residue prepeptide, consisting of an alpha-helical leader sequence of hydrophilic character, which is separated from the C-terminus (propeptide) by a characteristic proteolytic processing site (Pro-2 Arg-1 Ile1). Although pro-gallidermin differs from pro-epidermin (a recently isolated lantibiotic) only by a single amino acid residue exchange. Leu instead of Ile, the N-terminus of the prepeptide differs by an additional two exchanges.     

Carbon metabolism in Bradyrhizobium japonicum bacteroids

Abstract Carbon metabolism in Bradyrhizobium japonicum bacteroids is reviewed. Additionally, the bacteroid tricarboxylic acid (TCA) cycle and its regulation under oxygen-limited conditions is considered, with emphasis on possible sites of TCA cycle rate-limiting reactions. Furthermore, we consider other adaptive pathways that may be employed by these organisms while in symbiosis. These pathways include: (1) a poly-β-hydroxy-butyrate shunt, (2) a malate-aspartate shuttle, (3) an α-ketoglutarate-glutamate shunt, (4) a modified dicarboxylic acid cycle, and (5) fermentation pathways leading to lactate, acetaldehyde and ethanol. The effects of oxygen limitation on host carbon metabolism are also considered briefly.     

Sexual differentiation,gonad development,and spawning seasonality of the Hawaiian butterflyfish,Chaetodon multicinctus

Synopsis The reproductive biology of the coral reef butterflyfish,Chaetodon multicinctus, was investigated by histological examination of gonads sampled over an 18 month period from a shallow inshore population on Oahu, Hawaii. Most gonads developed directly from previously undifferentiated tissue. Ovarian development (the structural formation of lamellae and primary oocytes) was observed in fish ≥44 mm and testicular development (the formation of spermatogenic crypts) in fish ≥62 mm standard length (SL). In addition, testis formation was identified within the ovarian lamellae of several differentiated but immature fish. It is hypothesized that prematurational sex change may facilitate monogamy within the highly competitive social structure of this site attached species. Oocyte development in mature females was marked by distinct phases of primary growth, the formation of yolk vesicles, and vitellogenesis. Spawning activity was histologically identified by the maturation and hydration of fully yolked oocytes, and presence of postovulatory follicles. Recently spawned females from field collections and experimental gonadotropin-treatments exhibited postovulatory follicles that were estimated to persist at least 24 h after ovulation. Atresia of yolked oocytes was classified into four stages of cell degeneration and resorption. Monthly analyses of oocyte development and atresia within the sample population show thatC. multicinctus has a protracted annual spawning season with a major peak during the early spring and evidence of spawning activity among some individuals in the fall. Histological analyses of spawning activity provide more accurate and unambiguous information than do traditional gonadosomatic assays in this and probably other coral reef fishes.     

The brain organization of butterflyfishes

Synopsis The encephalization indices of angelfishes (Pomacanthidae) and butterflyfishes (Chaetodontidae) are typical of advanced perciform fishes: both families lie in the upper part of the polygon of teleost indices. The chaetodontids seem to be a little more encephalized than pomacanthids. The general morphology of the brains in both families is very similar: small olfactory bulbs, large optic tectum and a cerebellum which covers the brain structures in front of it like a cap. This morphology is shared by another family of the coral reef biotope, the Acanthuridae. The histological architecture is also typical of advanced teleosts, with a cortex-like pallium, a laminated nucleus geniculatus (= pretectalis superficialis), a complex valvula cerebelli and a corpus glomerulosum with a clear neuropile centre. The quantitative analysis of the main subdivisions of the brain, either from relative volumes or from indices, shows small olfactory bulbs (microsmy) but important telencephalic and diencephalic centres, large tectal centres (vision) and large cerebellum (precise locomotion). Many of these peculiarities are shared by other fishes inhabiting coral reefs. The differences between the two families seem to be primarily correlated with food habits: the angelfishes, which are sponge-feeders and may have an overweight due to the ballast of the sponge-skeleton in their digestive tract, and which do not need either such good vision or such precise locomotion to pick up their prey, could be a little less encephalized than the butterflyfishes.