Autoimmune islet destruction in spontaneous type 1 diabetes is not beta-cell exclusive

Pancreatic islets of Langerhans are enveloped by peri-islet Schwann cells (pSC), which express glial fibrillary acidic protein (GFAP) and S100beta. pSC-autoreactive T- and B-cell responses arise in 3- to 4-week-old diabetes-prone non-obese diabetic (NOD) mice, followed by progressive pSC destruction before detectable beta-cell death. Humans with probable prediabetes generate similar autoreactivities, and autoantibodies in islet-cell autoantibody (lCA) -positive sera co-localize to pSC. Moreover, GFAP-specific NOD T-cell lines transferred pathogenic peri-insulitis to NOD/severe combined immunodeficient (NOD/SCID) mice, and immunotherapy with GFAP or S100beta prevented diabetes. pSC survived in rat insulin promoter Iymphocytic choriomeningitis virus (rip-LCMV) glycoprotein/CD8+ T-cell receptor(gp) double-transgenic mice with virus-induced diabetes, suggesting that pSC death is not an obligate consequence of local inflammation and beta-cell destruction. However, pSC were deleted in spontaneously diabetic NOD mice carrying the CD8+/8.3 T-cell receptor transgene, a T cell receptor commonly expressed in earliest islet infiltrates. Autoimmune targeting of pancreatic nervous system tissue elements seems to be an integral, early part of natural type 1 diabetes.     

Species traits dictate seasonal-dependent responses of octocoral–algal symbioses to elevated temperature and ultraviolet radiation

Coral Reefs - Ultraviolet radiation (UVR) can exacerbate the effects of elevated seawater temperatures concomitant with climate change. Such stressors can collapse the mutualism of scleractinian...     

Rhesus macaque KIR bind human MHC class I with broad specificity and recognize HLA-C more effectively than HLA-A and HLA-B

Human killer cell immunoglobulin-like receptors (KIR) recognize A3/11, Bw4, C1, and C2 epitopes carried by mutually exclusive subsets of human leukocyte antigen (HLA)-A, -B, and -C allotypes. Chimpanzee and orangutan have counterparts to HLA-A, -B, and -C, and KIR that recognize the A3/11, Bw4, C1, and C2 epitopes, either individually or in combination. Because rhesus macaque has counterparts of HLA-A and -B, but not HLA-C, we expected that rhesus KIR would better recognize HLA-A and -B, than HLA-C. Comparison of the interactions of nine rhesus KIR3D with 95 HLA isoforms, showed the KIR have broad specificity for HLA-A, -B, and -C, but vary in avidity. Considering both the strength and breadth of reaction, HLA-C was the major target for rhesus KIR, followed by HLA-B, then HLA-A. Strong reactions with HLA-A were restricted to the minority of allotypes carrying the Bw4 epitope, whereas strong reactions with HLA-B partitioned between allotypes having and lacking Bw4. Contrasting to HLA-A and -B, every HLA-C allotype bound to the nine rhesus KIR. Sequence comparison of high- and low-binding HLA allotypes revealed the importance of polymorphism in the helix of the α₁ domain and the peptide-binding pockets. At peptide position 9, nonpolar residues favor binding to rhesus KIR, whereas charged residues do not. Contrary to expectation, rhesus KIR bind more effectively to HLA-C, than to HLA-A and -B. This property is consistent with major histocompatibility complex (MHC)-C having evolved in hominids to be a generally superior ligand for KIR than MHC-A and MHC-B.     

Response of Millepora alcicornis (Milleporina: Milleporidae) to two bleaching events at Puerto Morelos reef, Mexican Caribbean

Two naturally occurring colonies of Millepora alcicornis were monitored during 1997 and 1998, both years in which this species bleached in the Mexican Caribbean. One colony (HL) was naturally exposed to a high light environment and another nearby colony (LL) was exposed to 5.9 times lower light levels due to shadowing by a pier. For 10 days in August 1997, seawater temperatures in the surrounding reef lagoon rose up to 1.5 degrees C above the 6-year August average. The HL colony bleached to white during this period, whereas, the LL colony remained dark-brown colored. The HL colony recovered its normal dark-brown coloration (reversible bleaching) within several weeks, during which time the seawater temperatures returned to average. The following year, for 10 days, seawater temperatures rose up to 3 degrees C above the 7-year August average and both colonies bleached to white and neither colony recovered (irreversible bleaching). Both colonies were rapidly overgrown by algae and hydroids and, as of June 2003, no recovery has taken place. Prior to the 1997 bleaching, experiments using solar radiation showed that the quantum yield of photosystem II charge separation of branches from HL and LL colonies were affected for several hours by exposure to ultraviolet radiation (UVR, 280 to 400 nm), but recovered by the same evening, suggesting that UVR does not have long-term effects on photochemistry in M. alcicornis. In situ effective quantum yield of photosystem II charge separation (deltaF/Fm') measurements before the 1998 bleaching event indicate that both colonies were healthy in terms of the physiological status of their endosymbionts. During and after the 1998 bleaching event, both colonies showed a reduction in deltaF/Fm' and consequently an increase in excitation pressure on photosystem II. The data suggest that temperature is not the only factor that causes bleaching and that solar radiation may play an important role in coral bleaching.     

Serum copper and zinc in industrial centers in Slovakia

The association between serum copper and zinc concentrations and age, sex, and other risk factors of cardiovascular disease in randomly selected adult volunteers aged 19–59 were investigated. There was a positive relationship between copper and age in both sexes, but zinc was negatively correlated with age in males only. Serum zinc was positively related to HDL-cholesterol in males. Serum copper was positively related to total cholesterol and LDL-cholesterol but negatively correlated to HDL-cholesterol in males. A positive relationship to body mass index was observed in females only. Subjects have been divided into a control group and a group with marked risk factors of cardiovascular disease. The levels of zinc were not different, whereas the levels of copper in both males and females were significantly higher in the risk group. Our results suggested a positive relationship between serum copper and cumulation of more factors of cardiovascular disease, however, their causal effect in humans has to be investigated further.     

Assessment of Acropora palmata in the Mesoamerican Reef System

The once-dominant shallow reef-building coral Acropora palmata has suffered drastic geographical declines in the wider Caribbean from a disease epidemic that began in the late 1970s. At present there is a lack of quantitative data to determine whether this species is recovering over large spatial scales. Here, we use quantitative surveys conducted in 107 shallow-water reef sites between 2010 and 2012 to investigate the current distribution and abundance of A. palmata along the Mesoamerican Reef System (MRS). Using historical data we also explored how the distribution and abundance of this species has changed in the northern portion of the MRS between 1985 and 2010–2012. A. palmata was recorded in only a fifth of the surveyed reef sites in 2010–2012. In the majority of these reef sites the presence of A. palmata was patchy and rare. Only one site (Limones reef), in the northernmost portion of the MRS, presented considerably high A. palmata cover (mean: 34.7%, SD: 24.5%). At this site, the size-frequency distribution of A. palmata colonies was skewed towards small colony sizes; 84% of the colonies were healthy, however disease prevalence increased with colony size. A comparison with historical data showed that in the northern portion of the MRS, in 1985, A. palmata occurred in 74% of the 31 surveyed sites and had a mean cover of 7.7% (SD = 9.0), whereas in 2010–2012 this species was recorded in 48% of the sites with a mean cover of 2.9% (SD = 7.5). A. palmata populations along the MRS are failing to recover the distribution and abundance they had prior to the 1980s. Investigating the biological (e.g., population genetics) and environmental conditions (e.g., sources of stress) of the few standing reefs with relatively high A. palmata cover is crucial for the development of informed restoration models for this species.     

Genetic relationships of the hydrocoral Millepora alcicornis and its symbionts within and between locations across the Atlantic

Although the hydrocoral Millepora alcicornis is a prominent and ecologically relevant amphi-Atlantic reef builder, little attention has been given to its endosymbionts which are also involved in the survival and adaptation success of the species in different environments. In this study, we resolve the genetic relationships between M. alcicornis and its symbionts (Symbiodiniaceae) within both sides and across the Atlantic. The COI and 16S-rDNA regions were selected for the host tissues, and the 23S-rDNA and ITS regions were chosen for the symbionts. Phylogenetic networks consistently showed that host populations from the eastern Atlantic archipelagos (Canary and Cape Verde Islands) were more related to western Atlantic populations than they were between them. However, results for Symbiodiniaceae species varied according to the molecular marker used. Samples from Mexico were grouped as Symbiodinium sp. (formerly Symbiodinium clade A) by both markers. Specimens from Puerto Rico were grouped as either Symbiodinium sp. or Breviolum sp. (formerly Symbiodinium clade B), according to the molecular marker used. Most samples from the eastern Atlantic were identified as Breviolum sp. by both markers, except for one sample from the Canary Islands and two samples from the Cape Verde Islands, which were identified as Cladocopium sp. (formerly Symbiodinium clade C) using ITS-rDNA. These results suggest that these two genera of Symbiodiniaceae may cohabit the same M. alcicornis colony. Because hydrocorals from the Canary Islands were phylogenetically related to the western Atlantic, but symbionts were more related to those of the Cape Verde Islands, the origin of the coral and its symbionts is probably different. This may be explained either by “horizontal” transmission, i.e. acquisition from the environment, or by a change in the dominant symbiont composition within the host. The flexibility of this hydrocoral to select symbionts, depending on environmental conditions, can provide new insight to understand how this coral may face ongoing climate change.

     

Symbiotic Association Between Symbiodinium and the Gastropod Strombus gigas: Larval Acquisition of Symbionts

The importance of the dinoflagellate Symbiodinium sp. was studied in the early life stages of the gastropod Strombus gigas. This dinoflagellate was not found in the eggs or the gelatinous mass surrounding the eggs of the mollusk; therefore, Symbiodinium is not inherited directly. To determine whether the planktonic veligers can acquire these algae from the environment, they were exposed to freshly isolated Symbiodinium from adult S. gigas (homologous). The optimal stage for Symbiodinium inoculation was found at 48 h post-hatching. Survival and growth rates of veligers and juveniles were higher when inoculated with freshly isolated Symbiodinium in conjunction with daily feeding of Isochrysis spp. Veligers inoculated with Symbiodinium freshly isolated from three host species elicited distinct responses: (1) veligers did not take up Symbiodinium isolated from the hydrozoan Millepora alcicornis suggesting that there is discrimination on contact prior to ingestion, (2) veligers did take up Symbiodinium isolated from the anemone Bartholomea annulata, but the algae did not persist in the host tissue suggesting that selection against this type took place after ingestion or that the algae did not divide in the host, and (3) veligers did take up Symbiodinium isolated from Pterogorgia anceps where it persisted and was associated with metamorphosis of the larvae. In contrast, the Symbiodinium freshly isolated from S. gigas were not associated with metamorphosis and required an inducer such as the red alga Laurencia poitei. These data present a significant advancement for the establishment of a new approach in the aquaculture of this important but declining Caribbean species.