Mating in Heliothis virescens: transfer of juvenile hormone during copulation by male to female and stimulation of biosynthesis of endogenous juvenile hormone

Studies were undertaken to determine whether adult males of Heliothis virescens transfer juvenile hormone (JH) to females during copulation, and an in vitro radiochemical assay was used to determine whether mating causes an allatotropic effect, i.e., stimulation of JH biosynthesis by corpora allata (CA). In vitro, CA from 3-day-old mated females synthesized and released approximately 2.5 times total JH as that of CA from comparably aged virgin females. Of the homologues, JH II exhibited significant increase in mated females; JH I also increased but not significantly. JH III remained similar to that of virgin females. This is the first demonstration of an allatotropic effect of mating in moths. In contrast to the female, CA of virgin males did not produce any JH, but accessory sex glands (ASG) in 3-day-old males synthesized small amounts of JH. Immediately after adult emergence, male ASG contained approximately 1.5 ng JH I and II, which increased by 12 h after emergence and remained at this high level up to 54 h after emergence. JH III was barely detected in ASG. JH in ASG of mated male immediately after uncoupling was depleted almost completely, and 24 h later recovered to levels comparable to that of 54-h-old virgin male. Virgin female bursa copulatrix did not contain any JH, but mated female bursa, immediately after uncoupling, had JH at levels comparable to that observed in virgin male ASG. By 6 h after uncoupling, JH levels decreased dramatically in mated female bursa. These data suggest the transfer of JH to females by the male.

Cloning and expression of apolipophorin-III from the common cutworm, Spodoptera litura

We have cloned apolipophorin-III (apoLp-III) cDNA from adult fat body of Spodoptera litura. The sequence encodes a 188 amino acid polypeptide including a 22 amino acid leader peptide. The circular dichroism spectrum from the purified apoLp-III indicated a considerable content of alpha-helix. Sequence alignment showed that S. litura apoLp-III has a relatively high degree of sequence identity with the apoLps-III of lepidopteran, Manduca sexta (72%), Galleria mellonella (67%), Bombyx mori (60%). These alignments with four lepidopteran apoLps-III showed highly identical residues and conservative replacements at a degree of 86%. Levels of mRNA from last instar larval fat body and adult fat body were compared through Northern blot analysis using 32-P-labeled 704 bp apoLp-III cDNA probe. A 850 bp mRNA was detected in both stages and mRNA level of day 1 adult fat body was much higher than that of last instar larval fat body. The tissue-distribution of apoLp-III mRNA in adult ovary and testis was also examined and we confirmed the presence of apoLp-III mRNA in ovary and testis although apoLp-III was expressed in these tissues at very low levels compared with the adult fat body.

Choline Derivatives Involved in Osmotolerance of Penicillium fellutanum

Penicillium fellutanum is osmotolerant and xerotolerant when cultured in a low-phosphate medium containing 3 M NaCl. Glycerol and erythritol accumulated in cultures with NaCl concentrations up to 2 M; glycerol was the only detectable polyol in cultures containing 3 M NaCl. In cultures with 3 M NaCl, the intracellular levels of glycine betaine and choline-O-sulfate were 22- and 2.6-fold greater (70 and 46 mM), respectively, than those of cultures without added NaCl. The levels of glycine betaine and glycerol decreased in mycelia transferred from a medium containing 3 M NaCl into a fresh medium without added NaCl. NaCl at 3 M inhibited mycelial mass accumulation; this inhibition was partially corrected by supplementation of cultures with glycine betaine (2 mM) or choline-O-sulfate (10 mM). The presence of exogenous choline chloride (2 mM) in plate cultures protected the cells from stress from 3 M NaCl. The data suggest that glycine betaine and choline-O-sulfate are secondary osmoprotectants which are effective at the point that the cell is incapable of synthesizing more glycerol.

A case of adrenal cavernous hemangioma

Adrenal hemangiomas are rare tumor. Only 29 surgical cases have been reported. Although rare, adrenal hemangiomas should be included in the differential diagnosis of adrenal neoplasms. We report an additional case of adrenal hemangioma that was removed surgically, and the pertinent literature is reviewed.

Prevention of ultraviolet radiation-induced suppression of accessory cell function of Langerhans cells by Aloe vera gel components

The active components of Aloe vera gel that can prevent ultraviolet B (UVB)-induced suppression of accessory cell function of Langerhans cells (LC) were purified by activity-guided sequential fractionation followed by in vitro functional assay. The functional assay was based on the fact that exposure of freshly isolated murine epidermal cells (EC) to UVB radiation resulted in impairment of accessory cell function of LC, as measured by their ability to support anti-CD3 monoclonal antibody (mAb)-primed T-cell mitogenesis. This UVB-suppressed LC accessory cell function was prevented by addition of partially purified Aloe gel components to cultures of UVB-irradiated EC. The Aloe gel components appeared to prevent events occurring within the first 24 h after UVB irradiation that lead to the impairment of accessory cell function. The Aloe gel components did not cause proliferation of anti-CD3 mAb-primed T-cells, nor did induce proliferation of normal EC. The activity-guided final purification of Aloe gel components resulted in the isolation of two components. Both of the components were small molecular weight (MW) substances with an apparent MW of less than 1,000 Da but different from each other in net charge characteristics at pH 7.4. These results suggest that Aloe vera gel contains at least two small molecular weight immunomodulators that may prevent UVB-induced immune suppression in the skin.

Aloesin up-regulates cyclin E/CDK2 kinase activity via inducing the protein levels of cyclin E, CDK2, and CDC25A in SK-HEP-1 cells

In the present study, we show that aloesin, which is a low molecular weight ingredients present in Aloe vera, stimulates the proliferation of cultured human hepatoma SK-HEP-1 cells. The incorporation of [3H] thymidine into DNA in the cell cultures was significantly increased at a dose of 10 microM aloesin. The aloesin-induced DNA synthesis appears to require newly synthesized proteins because cycloheximide treatment blocked the DNA synthesis evoked by this compound. We then examined whether this compound increases the intracellular levels of cell cycle regulators by immunoblotting. The data showed that aloesin increased the levels of cyclin E, CDK2, and CDC25A in SK-HEP-1 cells. In addition, immuno-complex kinase assays showed that aloesin up-regulated the enzyme activity of cyclin E/CDK2 kinase in a dose-dependent manner. Collectively, these results suggest that aloesin stimulates the proliferation of SK-HEP-1 cells by inducing the intracellular levels of cyclin E/CDK2 kinase complex and CDC25A, which, together, result in the up-regulation of cyclin E-dependent kinase activity.

Utilization of phosphocholine from extracellular complex polysaccharide as a source of cytoplasmic choline derivatives in Penicillium fellutanum

Penicillium fellutanum produces a phosphorylated, choline-containing extracellular polysaccharide, peptidophosphogalactomannan (pP(x)GM) [where x is the number of phosphodiester residues]). The 13C-methyl-labeled pP(x)GM ([methyl-13C]pP(x)GM) was prepared from the cultures supplemented with L-[methyl-13C]methionine and was used as a probe to monitor the fate of phosphocholine in this polymer. The addition of [methyl-13C]pP(x)GM to growing cultures in low-phosphate medium resulted in the disappearance within 5 days of [methyl-13C]phosphocholine and N,N'-dimethylphosphoethanolamine from the added [methyl-13C]pP(x)GM. Two 13C-methyl-enriched cytoplasmic solutes, choline-O-sulfate and glycine betaine, were found in mycelial extracts, suggesting that phosphocholine-containing extracellular pP(x)GM of P. fellutanum is a precursor of intracellular choline-O-sulfate and glycine betaine. The mycelia cultured in low-phosphate (2 mM) medium contained glycine betaine and 1.5-fold more choline-O-sulfate than those grown in high-phosphate (20 mM) medium. The high levels of extracellular nonspecific phosphocholine:phosphocholine hydrolase and acid phosphomonoesterase observed in the low-phosphate culture medium are likely related to the release of phosphocholine from pP(x)GM and hydrolysis of phosphocholine, respectively. These results suggest that extracellular pP(x)GM of P. fellutanum provides phosphate needed as the environment becomes depleted of this nutrient. Choline, in excess of that needed immediately, is stored in the cytoplasm in forms that can be reutilized.

Target theory and the photoinactivation of Photosystem II

Application of target theory to the photoinactivation of Photosystem II in pea leaf discs (Park et al. 1995, 1996a,b) reveals that there is a critical light dosage below which there is complete photoprotection and above which there is photoinactivation (i.e a light-induced loss of oxygen flash yield). The critical dosage is about 3 mol photons m(-2) for medium and high light-grown leaves and 0.36 mol photons m(-2) for low light-grown leaves. Photoinactivation is a one-hit process with an effective cross-section of 0.045 m(2) mol(-1) photons which does not vary with growth irradiance, unlike the cross-section for oxygen evolution which increases with decreasing growth irradiance. The cross-section for oxygen evolution increased by about 20% following exposure to 6.8 mol photons m(-2) which may be due to energy transfer from photoinactivated units to functional Photosystem II units. We propose that the photoinactivation of PS II begins when a small group of PS II pigment molecules whose structure is uninfluenced by growth irradiance, becomes uncoupled energetically from the rest of the photosynthetic unit and thus no longer transfers excitions to P680. De-excitation of this group of pigment molecules provides the energy which leads to the damage of Photosystem II. Treatment of pea leaves with dithiothreitol, an inhibitor of the xanthophyll cycle, decreases the critical dosage i.e. decreases photoprotection but has no effect on the PS II photoinactivation cross-section. Treatment with 1 μM nigericin increased the photoinactivation cross-section of PS II as did exposure to lincomycin which inhibits D1 protein synthesis and thus the repair of PS II reaction centres.

Electron transport to oxygen mitigates against the photoinactivation of Photosystem II in vivo

The role of electron transport to O2 in mitigating against photoinactivation of Photosystem (PS) II was investigated in leaves of pea (Pisum sativum L.) grown in moderate light (250 μmol m(-2) s(-1)). During short-term illumination, the electron flux at PS II and non-radiative dissipation of absorbed quanta, calculated from chlorophyll fluorescence quenching, increased with increasing O2 concentration at each light regime tested. The photoinactivation of PS II in pea leaves was monitored by the oxygen yield per repetitive flash as a function of photon exposure (mol photons m(-2)). The number of functional PS II complexes decreased nonlinearly with increasing photon exposure, with greater photoinactivation of PS II at a lower O2 concentration. The results suggest that electron transport to O2, via the twin processes of oxygenase photorespiration and the Mehler reaction, mitigates against the photoinactivation of PS II in vivo, through both utilization of photons in electron transport and increased nonradiative dissipation of excitation. Photoprotection via electron transport to O2 in vivo is a useful addition to the large extent of photoprotection mediated by carbon-assimilatory electron transport in 1.1% CO2 alone.

Photoinactivation of photosystem II by cumulative exposure to short light pulses during the induction period of photosynthesis

Photoinactivation of Photosystem (PS) II in vivo was investigated by cumulative exposure of pea, rice and spinach leaves to light pulses of variable duration from 2 to 100 s, separated by dark intervals of 30 min. During each light pulse, photosynthetic induction occurred to an extent depending on the time of illumination, but steady-state photosynthesis had not been achieved. During photosynthetic induction, it is clearly demonstrated that reciprocity of irradiance and duration of illumination did not hold: hence the same cumulative photon exposure (mol m(-2)) does not necessarily give the same extent of photoinactivation of PS II. This contrasts with the situation of steady-state photosynthesis where the photoinactivation of PS II exhibited reciprocity of irradiance and duration of illumination (Park et al. (1995) Planta 196: 401-411). We suggest that, for reciprocity to hold between irradiance and duration of illumination, there must be a balance between photochemical (qP) and non-photochemical (NPQ) quenching at all irradiances. The index of susceptibility to light stress, which represents an intrinsic ability of PS II to balance photochemical and non-photochemical quenching, is defined by the quotient (1-qP)/NPQ. Although constant in steady-state photosynthesis under a wide range of irradiance (Park et al. (1995). Plant Cell Physiol 36: 1163-1169), this index of susceptibility for spinach leaves declined extremely rapidly during photosynthetic induction at a given irradiance, and, at a given cumulative photon exposure, was dependent on irradiance. During photosynthetic induction, only limited photoprotective strategies are developed: while the transthylakoid pH gradient conferred some degree of photoprotection, neither D1 protein turnover nor the xanthophyll cycle was operative. Thus, PS II is more easily photoinactivated during photosynthetic induction, a phenomenon that may have relevance for understorey leaves experiencing infrequent, short sunflecks.

The grand design of photosynthesis: Acclimation of the photosynthetic apparatus to environmental cues

Dynamic acclimation of the photosynthetic apparatus in response to environmental cues, particularly light quantity and quality, is a widely-observed and important phenomenon which contributes to the tolerance of plants against stress and helps to maintain, as far as possible, optimal photosynthetic efficiency and resource utilization. This mini-review represents a scrutiny of a number of possible photoreceptors (including the two photosystems acting as light sensors) and signal transducers that may be involved in producing acclimation responses. We suggest that regulation by signal transduction may be effected at each of several possible points, and that there are multiple regulatory mechanisms for photosynthetic acclimation.

Respiratory distress syndrome and tracheoesophageal fistula: management with high-frequency ventilation

An 1180-g infant with esophageal atresia and tracheoesophageal fistula developed life-threatening respiratory distress syndrome. Conventional mechanical ventilation resulted in gastric perforation and pneumoperitoneum. High-frequency ventilation stabilized the infant, permitting distal occlusion of the esophagus with a Silastic band. Fistula ligation was subsequently performed under more optimal physiologic conditions.

Early and late surfactant treatment in preterm triplets

Preterm triplets were treated with calf lung surfactant extract (CLSE). Two were treated at birth without development of respiratory distress syndrome (RDS); one was treated after development of RDS, with rapid improvement. These cases demonstrated the efficacy of exogenous surfactant and the potential benefit of prophylaxis (early treatment) over late treatment. Although various exogenous surfactants have been used successfully to treat or prevent RDS in preterm infants, the optimal time of surfactant treatment has not been established. Surfactant therapy at birth results in a reduction in the incidence and severity of RDS, but it could lead to unnecessary treatment in a significant portion of patients. On the other hand, delaying treatment is likely to lessen the benefits of exogenous surfactant by various factors, including barotrauma and oxygen toxicity. The triplets in this report were treated with Infasurf CLSE. Two were treated at birth without development of RDS, but one was treated after development of RDS, with rapid improvement of respiratory status.