Ultrastructure of type-I salivary-gland acini in four species of ticks and the influence of hydration states on the type-I acini ofAmblyomma americanum

We describe the ultrastructure of type-I salivary-gland acini in two argasid and two ixodid species. The basic cell types in the agranular or type-I acini, and their associations, are very similar in argasids and ixodids; therefore, we propose an anatomical nomenclature for cells in the type-I acinus based on the adult ixodidsAmblyomma americanum andDermacentor variabilis, and the argasid adultArgas (Persicargas) arboreus and on nymphalOrnithodoros moubata. Four cell types were present in all specimens: one central lamellate cell, a variable number of peripheral lamellate cells, a variable number of peritubular cells depending on the species, and one circumlumenal cell. The lamellate cells had infolded basal plasma membranes that presented an amplified surface area to the hemolymph. These cells most likely secreted the fluid involved in water vapor uptake by ticks. ForAmblyomma americanum females, abundant K⁺-dependent, ouabain-sensitive Na⁺, K⁺-ATPase complexes were located on the infolded basal plasma membranes of the lamellate cells. Apical membranes of the lamellate cells, and plasma membranes of other cell types in the acinus had little or no evidence of Na⁺, K⁺-ATPase activity. Only the central lamellate cell extended from the hemolymph of the acinus to its lumen; peripheral cells did not contact the lumen. Except when the ticks were rehydrating, lipid inclusions were common features in the lamellate cells of the ixodids. Lipid inclusions were not seen in argasid type I acini; however, glycogen deposits were common. To determine if acinar cells respond to the changing hydration state of the tick, unfed femaleA. americanum were subjected to dehydration/rehydrating conditions. During rehydration, mitochondria in the lamellate cells changed from a matrix of medium electron-density and intermembrane space (orthodox configuration) to a matrix of greater density and larger intermembrane space (condensed configuration). The orthodox configuration was consistently observed in control and dehydrating ticks. The condensed configuration was the norm for mitochondria in lamellate cells of rehydrating ticks. Lipid inclusions were depleted in the rehydrating ticks compared to control or dehydrating ticks. Acini appeared to be reverting to the control or desiccated state when ticks were returned to low humidity, suggesting that these changes were cyclical. Nymphs ofO. moubata subjected to the same dehydration/rehydrating conditions showed no obvious ultrastructural changes.     

Enhancement of α-lactalbumin-like activity in mammary explants from pregnant rats in the absence of exogenous prolactin

Mammary explants from pregnant rats showed a progressive increase in α-lactalbumin activity during culture with insulin, hydrocortisone and prolactin. Unexpectedly, culture with only insulin and hydrocortisone produced a similar rate of increase of α-lactalbumin-like activity, but this increase commenced about 24 hr later. The delay suggests that the enhanced activity effected by insulin and hydrocortisone is not a reflection of carry-over of endogenous mammotrophic hormones. Insulin plus hydrocortisone did not stimulate casein or fatty acid synthesis by pregnancy tissue, and did not enhance α-lactalbumin-like activity in virgin rat mammary explants. Enhancement of this activity by insulin plus hydrocortisone in pregnant tissue was constant over a wide range of glucocorticoid concentrations, but was inhibited by progesterone. Available evidence indicates that the active factor in extracts from insulin-hydrocortisone-explants is a heat-stable protein which is either α-lactalbumin itself, or another molecule with similar specifier properties.     

Identification of Medically Actionable Secondary Findings in the 1000 Genomes

The American College of Medical Genetics and Genomics (ACMG) recommends that clinical sequencing laboratories return secondary findings in 56 genes associated with medically actionable conditions. Our goal was to apply a systematic, stringent approach consistent with clinical standards to estimate the prevalence of pathogenic variants associated with such conditions using a diverse sequencing reference sample. Candidate variants in the 56 ACMG genes were selected from Phase 1 of the 1000 Genomes dataset, which contains sequencing information on 1,092 unrelated individuals from across the world. These variants were filtered using the Human Gene Mutation Database (HGMD) Professional version and defined parameters, appraised through literature review, and examined by a clinical laboratory specialist and expert physician. Over 70,000 genetic variants were extracted from the 56 genes, and filtering identified 237 variants annotated as disease causing by HGMD Professional. Literature review and expert evaluation determined that 7 of these variants were pathogenic or likely pathogenic. Furthermore, 5 additional truncating variants not listed as disease causing in HGMD Professional were identified as likely pathogenic. These 12 secondary findings are associated with diseases that could inform medical follow-up, including cancer predisposition syndromes, cardiac conditions, and familial hypercholesterolemia. The majority of the identified medically actionable findings were in individuals from the European (5/379) and Americas (4/181) ancestry groups, with fewer findings in Asian (2/286) and African (1/246) ancestry groups. Our results suggest that medically relevant secondary findings can be identified in approximately 1% (12/1092) of individuals in a diverse reference sample. As clinical sequencing laboratories continue to implement the ACMG recommendations, our results highlight that at least a small number of potentially important secondary findings can be selected for return. Our results also confirm that understudied populations will not reap proportionate benefits of genomic medicine, highlighting the need for continued research efforts on genetic diseases in these populations.     

Skeletal muscle creatine kinase MB alterations in women marathon runners

Total creatine kinase (CK) and CK MB activities were determined in gastrocnemius muscle and serum obtained from 14 female marathon runners. The level of CK MB in muscle increased significantly (p less than 0.05) after chronic exercise training from 5.3% to 10.5% of the total CK activity, but not after acute exercise (post-marathon 8.9%). No significant differences in total CK activities were detected. However, the total CK activity in the muscles were significantly (p less than 0.05) less than those previously reported from the muscle of men runners (1800 U/g, 3000 U/g respectively). No significant correlation existed between fiber type and muscle CK MB activity. Additionally, trace amounts of mitochondrial CK and CK BB were present in muscle homogenates. A significant correlation was observed in the increase in mean serum total CK (597 UL-1) and CK MB (23 UL-1) activities 24 h after the race (r = 0.97, p less than 0.05). These results suggest that gastrocnemius muscle in women adapts to training with increased CK MB activities and imply that skeletal muscle is the major source of elevated serum CK MB activities in women marathon runners.     

Potential of Agrotis ipsilon nucleopolyhedrovirus for suppression of the black cutworm (Lepidoptera: Noctuidae) and effect of an optical brightener on virus efficacy.

Studies were performed in the laboratory, greenhouse and field to assess the potential of Agrotis ipsilon multicapsid nucleopolyhedrovirus (AgipMNPV) and a viral enhancing agent, M2R, for suppression of Agrotis ipsilon (Hufnagel). In laboratory droplet feeding bioassays, AgipMNPV was shown to be highly active against third-instar A. ipsilon. The optical brightener M2R significantly reduced LD50 estimates by approximately 160-fold, but had no direct effect on survival time estimates. In greenhouse trials, spray and bait formulations of AgipMNPV significantly reduced feeding damage to corn seedlings caused by third-instar A. ipsilon. In two sets of replicated field trials, bait formulations of AgipMNPV significantly reduced feeding damage to corn seedlings by third-instar A. ipsilon. However, there were no beneficial effects attributable to the inclusion of M2R in AgipMNPV formulations under greenhouse or field conditions. It seems likely that in an appropriately designed pest management program AgipMNPV could be used to suppress field populations of early and mid-instar A. ipsilon.     

Acanthocephaloides cyrusi n. sp. (Acanthocephala: Arhythmacanthidae) from southeast African teleost fishes

A new species,Acanthocephaloides cyrusi, is described from the fishesSolea bleekeri andPomadasys commersoni from Lake St. Lucia, Natal, South Africa. It is distinguished from the other species in the genus by the more marked sexual dimorphism in length, the arrangement of hooks, the proboscis with the longest hooks at the anterior-most extremity and the greater size of the proboscis hooks and body spines. An acanthella, which may represent this species, was found in the tanaidApseudes digitalis.     

Bacterial oxidation of polythionates: determination of tetrathionate with an ion-selective electrode.

A commercially available ion-selective electrode for nitrate was used to continuously monitor tetrathionate oxidation by Thiobacillus dentrificans. The electrode was much more sensitive to tetrathionate than to nitrate. The same electrode could also be used for the determination of trithionate.